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-rw-r--r--fs/erofs/Kconfig212
-rw-r--r--fs/erofs/Makefile12
-rw-r--r--fs/erofs/compress.h89
-rw-r--r--fs/erofs/data.c534
-rw-r--r--fs/erofs/decompressor.c517
-rw-r--r--fs/erofs/decompressor_crypto.c182
-rw-r--r--fs/erofs/decompressor_deflate.c203
-rw-r--r--fs/erofs/decompressor_lzma.c236
-rw-r--r--fs/erofs/decompressor_zstd.c220
-rw-r--r--fs/erofs/dir.c134
-rw-r--r--fs/erofs/erofs_fs.h469
-rw-r--r--fs/erofs/fileio.c217
-rw-r--r--fs/erofs/inode.c399
-rw-r--r--fs/erofs/internal.h539
-rw-r--r--fs/erofs/ishare.c214
-rw-r--r--fs/erofs/namei.c224
-rw-r--r--fs/erofs/super.c1146
-rw-r--r--fs/erofs/sysfs.c302
-rw-r--r--fs/erofs/xattr.c649
-rw-r--r--fs/erofs/xattr.h36
-rw-r--r--fs/erofs/zdata.c1935
-rw-r--r--fs/erofs/zmap.c838
-rw-r--r--fs/erofs/zutil.c316
23 files changed, 9623 insertions, 0 deletions
diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
new file mode 100644
index 000000000..2dfc31358
--- /dev/null
+++ b/fs/erofs/Kconfig
@@ -0,0 +1,212 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+config EROFS_FS
+ tristate "EROFS filesystem support"
+ depends on BLOCK
+ select CRC32
+ select CRYPTO if EROFS_FS_ZIP_ACCEL
+ select CRYPTO_DEFLATE if EROFS_FS_ZIP_ACCEL
+ select FS_IOMAP
+ select LZ4_DECOMPRESS if EROFS_FS_ZIP
+ select XXHASH if EROFS_FS_XATTR
+ select XZ_DEC if EROFS_FS_ZIP_LZMA
+ select XZ_DEC_MICROLZMA if EROFS_FS_ZIP_LZMA
+ select ZLIB_INFLATE if EROFS_FS_ZIP_DEFLATE
+ select ZSTD_DECOMPRESS if EROFS_FS_ZIP_ZSTD
+ help
+ EROFS (Enhanced Read-Only File System) is a modern, lightweight,
+ secure read-only filesystem for various use cases, such as immutable
+ system images, container images, application sandboxes, and datasets.
+
+ EROFS uses a flexible, hierarchical on-disk design so that features
+ can be enabled on demand: the core on-disk format is block-aligned in
+ order to perform optimally on all kinds of devices, including block
+ and memory-backed devices; the format is easy to parse and has zero
+ metadata redundancy, unlike generic filesystems, making it ideal for
+ filesystem auditing and remote access; inline data, random-access
+ friendly directory data, inline/shared extended attributes and
+ chunk-based deduplication ensure space efficiency while maintaining
+ high performance.
+
+ Optionally, it supports multiple devices to reference external data,
+ enabling data sharing for container images.
+
+ It also has advanced encoded on-disk layouts, particularly for data
+ compression and fine-grained deduplication. It utilizes fixed-size
+ output compression to improve storage density while keeping relatively
+ high compression ratios. Furthermore, it implements in-place
+ decompression to reuse file pages to keep compressed data temporarily
+ with proper strategies, which ensures guaranteed end-to-end runtime
+ performance under extreme memory pressure without extra cost.
+
+ For more details, see the web pages at <https://erofs.docs.kernel.org>
+ and the documentation at <file:Documentation/filesystems/erofs.rst>.
+
+ To compile EROFS filesystem support as a module, choose M here. The
+ module will be called erofs.
+
+ If unsure, say N.
+
+config EROFS_FS_DEBUG
+ bool "EROFS debugging feature"
+ depends on EROFS_FS
+ help
+ Print debugging messages and enable more BUG_ONs which check
+ filesystem consistency and find potential issues aggressively,
+ which can be used for Android eng build, for example.
+
+ For daily use, say N.
+
+config EROFS_FS_XATTR
+ bool "EROFS extended attributes"
+ depends on EROFS_FS
+ default y
+ help
+ Extended attributes are name:value pairs associated with inodes by
+ the kernel or by users (see the attr(5) manual page, or visit
+ <http://acl.bestbits.at/> for details).
+
+ If unsure, say N.
+
+config EROFS_FS_POSIX_ACL
+ bool "EROFS Access Control Lists"
+ depends on EROFS_FS_XATTR
+ select FS_POSIX_ACL
+ default y
+ help
+ Posix Access Control Lists (ACLs) support permissions for users and
+ groups beyond the owner/group/world scheme.
+
+ To learn more about Access Control Lists, visit the POSIX ACLs for
+ Linux website <http://acl.bestbits.at/>.
+
+ If you don't know what Access Control Lists are, say N.
+
+config EROFS_FS_SECURITY
+ bool "EROFS Security Labels"
+ depends on EROFS_FS_XATTR
+ default y
+ help
+ Security labels provide an access control facility to support Linux
+ Security Models (LSMs) accepted by AppArmor, SELinux, Smack and TOMOYO
+ Linux. This option enables an extended attribute handler for file
+ security labels in the erofs filesystem, so that it requires enabling
+ the extended attribute support in advance.
+
+ If you are not using a security module, say N.
+
+config EROFS_FS_BACKED_BY_FILE
+ bool "File-backed EROFS filesystem support"
+ depends on EROFS_FS
+ default y
+ help
+ This allows EROFS to use filesystem image files directly, without
+ the intercession of loopback block devices or likewise. It is
+ particularly useful for container images with numerous blobs and
+ other sandboxes, where loop devices behave intricately. It can also
+ be used to simplify error-prone lifetime management of unnecessary
+ virtual block devices.
+
+ If you don't want to enable this feature, say N.
+
+config EROFS_FS_ZIP
+ bool "EROFS Data Compression Support"
+ depends on EROFS_FS
+ default y
+ help
+ Enable EROFS compression layouts so that filesystems containing
+ compressed files can be parsed by the kernel.
+
+ If you don't want to enable compression feature, say N.
+
+config EROFS_FS_ZIP_LZMA
+ bool "EROFS LZMA compressed data support"
+ depends on EROFS_FS_ZIP
+ default y
+ help
+ Saying Y here includes support for reading EROFS file systems
+ containing LZMA compressed data, specifically called microLZMA. It
+ gives better compression ratios than the default LZ4 format, at the
+ expense of more CPU overhead.
+
+ Say N if you want to disable LZMA compression support.
+
+config EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS
+ int "EROFS LZMA default maximum decompression streams"
+ depends on EROFS_FS_ZIP_LZMA
+ range 1 NR_CPUS if SMP
+ range 1 1 if !SMP
+ default 16
+ help
+ By default EROFS allocates one LZMA decompression stream per CPU.
+ Each stream can hold a dictionary of up to 8 MiB taken from the
+ mounted image, so on systems with many CPUs this can reserve a lot
+ of memory. This caps the default; the lzma_streams module parameter
+ still overrides it.
+
+ If unsure, keep the default of 16.
+
+config EROFS_FS_ZIP_DEFLATE
+ bool "EROFS DEFLATE compressed data support"
+ depends on EROFS_FS_ZIP
+ help
+ Saying Y here includes support for reading EROFS file systems
+ containing DEFLATE compressed data. It gives better compression
+ ratios than the default LZ4 format, while it costs more CPU
+ overhead.
+
+ If unsure, say N.
+
+config EROFS_FS_ZIP_ZSTD
+ bool "EROFS Zstandard compressed data support"
+ depends on EROFS_FS_ZIP
+ help
+ Saying Y here includes support for reading EROFS file systems
+ containing Zstandard compressed data. It gives better compression
+ ratios than the default LZ4 format, while it costs more CPU
+ overhead and memory footprint.
+
+ If unsure, say N.
+
+config EROFS_FS_ZIP_ACCEL
+ bool "EROFS hardware decompression support"
+ depends on EROFS_FS_ZIP
+ help
+ Saying Y here includes hardware accelerator support for reading
+ EROFS file systems containing compressed data. It gives better
+ decompression speed than the software-implemented decompression, and
+ it costs lower CPU overhead.
+
+ Hardware accelerator support is an experimental feature for now and
+ file systems are still readable without selecting this option.
+
+ If unsure, say N.
+
+config EROFS_FS_PCPU_KTHREAD
+ bool "EROFS per-cpu decompression kthread workers"
+ depends on EROFS_FS_ZIP
+ help
+ Saying Y here enables per-CPU kthread workers pool to carry out
+ async decompression for low latencies on some architectures.
+
+ If unsure, say N.
+
+config EROFS_FS_PCPU_KTHREAD_HIPRI
+ bool "EROFS high priority per-CPU kthread workers"
+ depends on EROFS_FS_ZIP && EROFS_FS_PCPU_KTHREAD
+ default y
+ help
+ This permits EROFS to configure per-CPU kthread workers to run
+ at higher priority.
+
+ If unsure, say N.
+
+config EROFS_FS_PAGE_CACHE_SHARE
+ bool "EROFS page cache share support (experimental)"
+ depends on EROFS_FS && EROFS_FS_XATTR
+ select FS_STACK
+ help
+ This enables page cache sharing among inodes with identical
+ content fingerprints on the same machine.
+
+ If unsure, say N.
diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
new file mode 100644
index 000000000..304234967
--- /dev/null
+++ b/fs/erofs/Makefile
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-$(CONFIG_EROFS_FS) += erofs.o
+erofs-objs := super.o inode.o data.o namei.o dir.o sysfs.o
+erofs-$(CONFIG_EROFS_FS_XATTR) += xattr.o
+erofs-$(CONFIG_EROFS_FS_ZIP) += decompressor.o zmap.o zdata.o zutil.o
+erofs-$(CONFIG_EROFS_FS_ZIP_LZMA) += decompressor_lzma.o
+erofs-$(CONFIG_EROFS_FS_ZIP_DEFLATE) += decompressor_deflate.o
+erofs-$(CONFIG_EROFS_FS_ZIP_ZSTD) += decompressor_zstd.o
+erofs-$(CONFIG_EROFS_FS_ZIP_ACCEL) += decompressor_crypto.o
+erofs-$(CONFIG_EROFS_FS_BACKED_BY_FILE) += fileio.o
+erofs-$(CONFIG_EROFS_FS_PAGE_CACHE_SHARE) += ishare.o
diff --git a/fs/erofs/compress.h b/fs/erofs/compress.h
new file mode 100644
index 000000000..84c8e5258
--- /dev/null
+++ b/fs/erofs/compress.h
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2019 HUAWEI, Inc.
+ * https://www.huawei.com/
+ */
+#ifndef __EROFS_FS_COMPRESS_H
+#define __EROFS_FS_COMPRESS_H
+
+#include "internal.h"
+
+struct z_erofs_decompress_req {
+ struct super_block *sb;
+ struct page **in, **out;
+ unsigned int inpages, outpages;
+ unsigned short pageofs_in, pageofs_out;
+ unsigned int inputsize, outputsize;
+
+ unsigned int alg; /* the algorithm for decompression */
+ bool inplace_io, partial_decoding, fillgaps;
+ gfp_t gfp; /* allocation flags for extra temporary buffers */
+};
+
+struct z_erofs_decompressor {
+ int (*config)(struct super_block *sb, struct erofs_super_block *dsb,
+ void *data, int size);
+ const char *(*decompress)(struct z_erofs_decompress_req *rq,
+ struct page **pagepool);
+ int (*init)(void);
+ void (*exit)(void);
+ char *name;
+};
+
+#define Z_EROFS_SHORTLIVED_PAGE (-1UL << 2)
+#define Z_EROFS_PREALLOCATED_FOLIO ((void *)(-2UL << 2))
+
+/*
+ * Currently, short-lived pages are pages directly from buddy system
+ * with specific page->private (Z_EROFS_SHORTLIVED_PAGE).
+ * In the future world of Memdescs, it should be type 0 (Misc) memory
+ * which type can be checked with a new helper.
+ */
+static inline bool z_erofs_is_shortlived_page(struct page *page)
+{
+ return page->private == Z_EROFS_SHORTLIVED_PAGE;
+}
+
+static inline bool z_erofs_put_shortlivedpage(struct page **pagepool,
+ struct page *page)
+{
+ if (!z_erofs_is_shortlived_page(page))
+ return false;
+ erofs_pagepool_add(pagepool, page);
+ return true;
+}
+
+extern const struct z_erofs_decompressor z_erofs_lzma_decomp;
+extern const struct z_erofs_decompressor z_erofs_deflate_decomp;
+extern const struct z_erofs_decompressor z_erofs_zstd_decomp;
+extern const struct z_erofs_decompressor *z_erofs_decomp[];
+
+struct z_erofs_stream_dctx {
+ struct z_erofs_decompress_req *rq;
+ int no, ni; /* the current {en,de}coded page # */
+
+ unsigned int avail_out; /* remaining bytes in the decoded buffer */
+ unsigned int inbuf_pos, inbuf_sz;
+ /* current status of the encoded buffer */
+ u8 *kin, *kout; /* buffer mapped pointers */
+ void *bounce; /* bounce buffer for inplace I/Os */
+ bool bounced; /* is the bounce buffer used now? */
+};
+
+const char *z_erofs_stream_switch_bufs(struct z_erofs_stream_dctx *dctx,
+ void **dst, void **src, struct page **pgpl);
+const char *z_erofs_fixup_insize(struct z_erofs_decompress_req *rq,
+ const char *padbuf, unsigned int padbufsize);
+int __init z_erofs_init_decompressor(void);
+void z_erofs_exit_decompressor(void);
+int z_erofs_crypto_decompress(struct z_erofs_decompress_req *rq,
+ struct page **pgpl);
+int z_erofs_crypto_enable_engine(const char *name, int len);
+#ifdef CONFIG_EROFS_FS_ZIP_ACCEL
+void z_erofs_crypto_disable_all_engines(void);
+int z_erofs_crypto_show_engines(char *buf, int size, char sep);
+#else
+static inline void z_erofs_crypto_disable_all_engines(void) {}
+static inline int z_erofs_crypto_show_engines(char *buf, int size, char sep) { return 0; }
+#endif
+#endif
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
new file mode 100644
index 000000000..20962f8b6
--- /dev/null
+++ b/fs/erofs/data.c
@@ -0,0 +1,534 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ * https://www.huawei.com/
+ * Copyright (C) 2021, Alibaba Cloud
+ */
+#include "internal.h"
+#include <linux/filelock.h>
+#include <linux/sched/mm.h>
+#include <trace/events/erofs.h>
+
+void erofs_unmap_metabuf(struct erofs_buf *buf)
+{
+ if (!buf->base)
+ return;
+ kunmap_local(buf->base);
+ buf->base = NULL;
+}
+
+void erofs_put_metabuf(struct erofs_buf *buf)
+{
+ if (!buf->page)
+ return;
+ erofs_unmap_metabuf(buf);
+ folio_put(page_folio(buf->page));
+ buf->page = NULL;
+}
+
+void *erofs_bread(struct erofs_buf *buf, erofs_off_t offset, bool need_kmap)
+{
+ pgoff_t index = (buf->off + offset) >> PAGE_SHIFT;
+ struct folio *folio = NULL;
+
+ if (buf->page) {
+ folio = page_folio(buf->page);
+ if (folio_file_page(folio, index) != buf->page)
+ erofs_unmap_metabuf(buf);
+ }
+ if (!folio || !folio_contains(folio, index)) {
+ erofs_put_metabuf(buf);
+ folio = read_cache_folio(buf->mapping, index,
+ buf->mc ? erofs_read_meta_folio : NULL, NULL);
+ if (IS_ERR(folio))
+ return folio;
+ }
+ buf->page = folio_file_page(folio, index);
+ if (!need_kmap)
+ return NULL;
+ if (!buf->base)
+ buf->base = kmap_local_page(buf->page);
+ return buf->base + (offset & ~PAGE_MASK);
+}
+
+int erofs_init_metabuf(struct erofs_buf *buf, struct super_block *sb,
+ bool in_metabox)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+
+ buf->mc = false;
+ if (in_metabox) {
+ if (unlikely(!sbi->metabox_inode))
+ return -EFSCORRUPTED;
+ buf->mapping = sbi->metabox_inode->i_mapping;
+ return 0;
+ }
+ if (erofs_is_fileio_mode(sbi)) {
+ buf->mapping = sbi->managed_cache->i_mapping;
+ buf->mc = true;
+ } else {
+ buf->off = sbi->dif0.fsoff;
+ buf->mapping = sb->s_bdev->bd_mapping;
+ }
+ return 0;
+}
+
+void *erofs_read_metabuf(struct erofs_buf *buf, struct super_block *sb,
+ erofs_off_t offset, bool in_metabox)
+{
+ int err;
+
+ err = erofs_init_metabuf(buf, sb, in_metabox);
+ if (err)
+ return ERR_PTR(err);
+ return erofs_bread(buf, offset, true);
+}
+
+static int erofs_map_chunks(struct inode *inode, struct erofs_map_blocks *map)
+{
+ struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+ struct super_block *sb = inode->i_sb;
+ struct erofs_inode *vi = EROFS_I(inode);
+ struct erofs_inode_chunk_index *idx;
+ unsigned int unit = vi->chunkformat & EROFS_CHUNK_FORMAT_INDEXES ?
+ sizeof(*idx) : EROFS_BLOCK_MAP_ENTRY_SIZE;
+ erofs_blk_t addrmask = (vi->chunkformat & EROFS_CHUNK_FORMAT_48BIT) ?
+ BIT_ULL(48) - 1 : BIT_ULL(32) - 1;
+ u64 nr = map->m_la >> vi->chunkbits, chunksize = 1ULL << vi->chunkbits;
+ erofs_off_t pos = ALIGN(erofs_iloc(inode) + vi->inode_isize +
+ vi->xattr_isize, unit) + unit * nr;
+ /* m_llen will be clamped to EOF in the end */
+ erofs_off_t endpos = round_up(pos + 1, sb->s_blocksize);
+ u64 last, addr;
+
+ idx = erofs_read_metabuf(&buf, sb, pos, erofs_inode_in_metabox(inode));
+ if (IS_ERR(idx))
+ return PTR_ERR(idx);
+
+ map->m_la = nr << vi->chunkbits;
+ map->m_llen = 0;
+ nr = 0;
+ do {
+ if (unit == EROFS_BLOCK_MAP_ENTRY_SIZE) {
+ addr = le32_to_cpu(((__le32 *)idx)[nr]);
+ if (addr == (u32)EROFS_NULL_ADDR)
+ addr = EROFS_NULL_ADDR;
+ } else {
+ addr = (((u64)le16_to_cpu(idx[nr].startblk_hi) << 32) |
+ le32_to_cpu(idx[nr].startblk_lo)) & addrmask;
+ if (addr ^ (EROFS_NULL_ADDR & addrmask))
+ addr |= (u64)(le16_to_cpu(idx[nr].device_id) &
+ EROFS_SB(sb)->device_id_mask) << 48;
+ else
+ addr = EROFS_NULL_ADDR;
+ }
+ if (!nr) {
+ last = addr;
+ continue;
+ }
+ /* expand and account the prior chunk here */
+ map->m_llen += chunksize;
+ if (last != EROFS_NULL_ADDR)
+ last += erofs_blknr(sb, chunksize);
+ } while (addr == last && pos + (++nr) * unit < endpos);
+
+ if (last != EROFS_NULL_ADDR) {
+ map->m_pa = erofs_pos(sb, last & addrmask) - map->m_llen;
+ map->m_deviceid = last >> 48;
+ map->m_flags = EROFS_MAP_MAPPED;
+ }
+ if (addr == last)
+ map->m_llen += chunksize;
+ map->m_llen = min_t(erofs_off_t, map->m_llen,
+ round_up(inode->i_size - map->m_la, sb->s_blocksize));
+ erofs_put_metabuf(&buf);
+ return 0;
+}
+
+int erofs_map_blocks(struct inode *inode, struct erofs_map_blocks *map)
+{
+ struct super_block *sb = inode->i_sb;
+ struct erofs_inode *vi = EROFS_I(inode);
+ bool tailinline = (vi->datalayout == EROFS_INODE_FLAT_INLINE);
+ erofs_off_t pos;
+ int err = 0;
+
+ trace_erofs_map_blocks_enter(inode, map, 0);
+ map->m_deviceid = 0;
+ map->m_flags = 0;
+ if (map->m_la >= inode->i_size)
+ goto out;
+ if (vi->datalayout == EROFS_INODE_CHUNK_BASED) {
+ err = erofs_map_chunks(inode, map);
+ } else if (tailinline || vi->startblk != EROFS_NULL_ADDR) {
+ pos = erofs_pos(sb, erofs_iblks(inode) - tailinline);
+ map->m_flags = EROFS_MAP_MAPPED;
+ if (map->m_la < pos) {
+ map->m_pa = erofs_pos(sb, vi->startblk) + map->m_la;
+ map->m_llen = pos - map->m_la;
+ } else {
+ map->m_pa = erofs_iloc(inode) + vi->inode_isize +
+ vi->xattr_isize + erofs_blkoff(sb, map->m_la);
+ map->m_llen = inode->i_size - map->m_la;
+ map->m_flags |= EROFS_MAP_META;
+ if (erofs_blkoff(sb, map->m_pa) + map->m_llen >
+ sb->s_blocksize) {
+ erofs_err(sb, "inline data across blocks @ nid %llu", vi->nid);
+ return -EFSCORRUPTED;
+ }
+ }
+ }
+out:
+ map->m_plen = err ? 0 : map->m_llen;
+ trace_erofs_map_blocks_exit(inode, map, 0, err);
+ return err;
+}
+
+static void erofs_fill_from_devinfo(struct erofs_map_dev *map,
+ struct super_block *sb, struct erofs_device_info *dif)
+{
+ map->m_sb = sb;
+ map->m_dif = dif;
+ map->m_bdev = NULL;
+ if (dif->file && S_ISBLK(file_inode(dif->file)->i_mode))
+ map->m_bdev = file_bdev(dif->file);
+}
+
+int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
+{
+ struct erofs_dev_context *devs = EROFS_SB(sb)->devs;
+ struct erofs_device_info *dif;
+ erofs_off_t startoff;
+ int id;
+
+ erofs_fill_from_devinfo(map, sb, &EROFS_SB(sb)->dif0);
+ map->m_bdev = sb->s_bdev; /* use s_bdev for the primary device */
+ if (map->m_deviceid) {
+ down_read(&devs->rwsem);
+ dif = idr_find(&devs->tree, map->m_deviceid - 1);
+ if (!dif) {
+ up_read(&devs->rwsem);
+ return -ENODEV;
+ }
+ if (devs->flatdev) {
+ map->m_pa += erofs_pos(sb, dif->uniaddr);
+ up_read(&devs->rwsem);
+ return 0;
+ }
+ erofs_fill_from_devinfo(map, sb, dif);
+ up_read(&devs->rwsem);
+ } else if (devs->extra_devices && !devs->flatdev) {
+ down_read(&devs->rwsem);
+ idr_for_each_entry(&devs->tree, dif, id) {
+ if (!dif->uniaddr)
+ continue;
+
+ startoff = erofs_pos(sb, dif->uniaddr);
+ if (map->m_pa >= startoff &&
+ map->m_pa < startoff + erofs_pos(sb, dif->blocks)) {
+ map->m_pa -= startoff;
+ erofs_fill_from_devinfo(map, sb, dif);
+ break;
+ }
+ }
+ up_read(&devs->rwsem);
+ }
+ return 0;
+}
+
+/*
+ * bit 30: I/O error occurred on this folio
+ * bit 29: CPU has dirty data in D-cache (needs aliasing handling);
+ * bit 0 - 29: remaining parts to complete this folio
+ */
+#define EROFS_ONLINEFOLIO_EIO 30
+#define EROFS_ONLINEFOLIO_DIRTY 29
+
+void erofs_onlinefolio_init(struct folio *folio)
+{
+ union {
+ atomic_t o;
+ void *v;
+ } u = { .o = ATOMIC_INIT(1) };
+
+ folio->private = u.v; /* valid only if file-backed folio is locked */
+}
+
+void erofs_onlinefolio_split(struct folio *folio)
+{
+ atomic_inc((atomic_t *)&folio->private);
+}
+
+void erofs_onlinefolio_end(struct folio *folio, int err, bool dirty)
+{
+ int orig, v;
+
+ do {
+ orig = atomic_read((atomic_t *)&folio->private);
+ DBG_BUGON(orig <= 0);
+ v = dirty << EROFS_ONLINEFOLIO_DIRTY;
+ v |= (orig - 1) | (!!err << EROFS_ONLINEFOLIO_EIO);
+ } while (atomic_cmpxchg((atomic_t *)&folio->private, orig, v) != orig);
+
+ if (v & (BIT(EROFS_ONLINEFOLIO_DIRTY) - 1))
+ return;
+ folio->private = 0;
+ if (v & BIT(EROFS_ONLINEFOLIO_DIRTY))
+ flush_dcache_folio(folio);
+ folio_end_read(folio, !(v & BIT(EROFS_ONLINEFOLIO_EIO)));
+}
+
+struct erofs_iomap_iter_ctx {
+ struct page *page;
+ void *base;
+ struct inode *realinode;
+};
+
+static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
+ unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
+{
+ struct iomap_iter *iter = container_of(iomap, struct iomap_iter, iomap);
+ struct erofs_iomap_iter_ctx *ctx = iter->private;
+ struct inode *realinode = ctx ? ctx->realinode : inode;
+ struct super_block *sb = realinode->i_sb;
+ struct erofs_map_blocks map;
+ struct erofs_map_dev mdev;
+ int ret;
+
+ map.m_la = offset;
+ map.m_llen = length;
+ ret = erofs_map_blocks(realinode, &map);
+ if (ret < 0)
+ return ret;
+
+ iomap->offset = map.m_la;
+ iomap->length = map.m_llen;
+ iomap->flags = 0;
+ iomap->addr = IOMAP_NULL_ADDR;
+ if (!(map.m_flags & EROFS_MAP_MAPPED)) {
+ iomap->type = IOMAP_HOLE;
+ return 0;
+ }
+
+ if (!(map.m_flags & EROFS_MAP_META) || !erofs_inode_in_metabox(realinode)) {
+ mdev = (struct erofs_map_dev) {
+ .m_deviceid = map.m_deviceid,
+ .m_pa = map.m_pa,
+ };
+ ret = erofs_map_dev(sb, &mdev);
+ if (ret)
+ return ret;
+
+ if (flags & IOMAP_DAX)
+ iomap->dax_dev = mdev.m_dif->dax_dev;
+ else
+ iomap->bdev = mdev.m_bdev;
+ iomap->addr = mdev.m_dif->fsoff + mdev.m_pa;
+ if (flags & IOMAP_DAX)
+ iomap->addr += mdev.m_dif->dax_part_off;
+ }
+
+ if (map.m_flags & EROFS_MAP_META) {
+ iomap->type = IOMAP_INLINE;
+ /* read context should read the inlined data */
+ if (ctx) {
+ struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+ void *ptr;
+
+ ptr = erofs_read_metabuf(&buf, sb, map.m_pa,
+ erofs_inode_in_metabox(realinode));
+ if (IS_ERR(ptr))
+ return PTR_ERR(ptr);
+ iomap->inline_data = ptr;
+ ctx->page = buf.page;
+ ctx->base = buf.base;
+ }
+ } else {
+ iomap->type = IOMAP_MAPPED;
+ }
+ return 0;
+}
+
+static int erofs_iomap_end(struct inode *inode, loff_t pos, loff_t length,
+ ssize_t written, unsigned int flags, struct iomap *iomap)
+{
+ struct iomap_iter *iter = container_of(iomap, struct iomap_iter, iomap);
+ struct erofs_iomap_iter_ctx *ctx = iter->private;
+
+ if (ctx && ctx->base) {
+ struct erofs_buf buf = {
+ .page = ctx->page,
+ .base = ctx->base,
+ };
+
+ DBG_BUGON(iomap->type != IOMAP_INLINE);
+ erofs_put_metabuf(&buf);
+ ctx->base = NULL;
+ }
+ return written;
+}
+
+static DEFINE_IOMAP_ITER_NEXT_END(erofs_iomap_next, erofs_iomap_begin,
+ erofs_iomap_end);
+
+static const struct iomap_ops erofs_iomap_ops = {
+ .iomap_next = erofs_iomap_next,
+};
+
+int erofs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
+ u64 start, u64 len)
+{
+ if (erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout)) {
+ if (!IS_ENABLED(CONFIG_EROFS_FS_ZIP))
+ return -EOPNOTSUPP;
+ return iomap_fiemap(inode, fieinfo, start, len,
+ &z_erofs_iomap_report_ops);
+ }
+ return iomap_fiemap(inode, fieinfo, start, len, &erofs_iomap_ops);
+}
+
+/*
+ * since we dont have write or truncate flows, so no inode
+ * locking needs to be held at the moment.
+ */
+static int erofs_read_folio(struct file *file, struct folio *folio)
+{
+ struct iomap_read_folio_ctx read_ctx = {
+ .ops = &iomap_bio_read_ops,
+ .cur_folio = folio,
+ };
+ bool need_iput;
+ struct erofs_iomap_iter_ctx iter_ctx = {
+ .realinode = erofs_real_inode(folio_inode(folio), &need_iput),
+ };
+
+ trace_erofs_read_folio(iter_ctx.realinode, folio, true);
+ iomap_read_folio(&erofs_iomap_ops, &read_ctx, &iter_ctx);
+ if (need_iput)
+ iput(iter_ctx.realinode);
+ return 0;
+}
+
+static void erofs_readahead(struct readahead_control *rac)
+{
+ struct iomap_read_folio_ctx read_ctx = {
+ .ops = &iomap_bio_read_ops,
+ .rac = rac,
+ };
+ bool need_iput;
+ struct erofs_iomap_iter_ctx iter_ctx = {
+ .realinode = erofs_real_inode(rac->mapping->host, &need_iput),
+ };
+
+ trace_erofs_readahead(iter_ctx.realinode, readahead_index(rac),
+ readahead_count(rac), true);
+ iomap_readahead(&erofs_iomap_ops, &read_ctx, &iter_ctx);
+ if (need_iput)
+ iput(iter_ctx.realinode);
+}
+
+static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
+{
+ return iomap_bmap(mapping, block, &erofs_iomap_ops);
+}
+
+static ssize_t erofs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+ struct inode *inode = file_inode(iocb->ki_filp);
+
+ /* no need taking (shared) inode lock since it's a ro filesystem */
+ if (!iov_iter_count(to))
+ return 0;
+
+ if (IS_ENABLED(CONFIG_FS_DAX) && IS_DAX(inode))
+ return dax_iomap_rw(iocb, to, &erofs_iomap_ops);
+
+ if ((iocb->ki_flags & IOCB_DIRECT) && inode->i_sb->s_bdev) {
+ struct erofs_iomap_iter_ctx iter_ctx = {
+ .realinode = inode,
+ };
+
+ return iomap_dio_rw(iocb, to, &erofs_iomap_ops,
+ NULL, 0, &iter_ctx, 0);
+ }
+ return filemap_read(iocb, to, 0);
+}
+
+/* for uncompressed (aligned) files and raw access for other files */
+const struct address_space_operations erofs_aops = {
+ .read_folio = erofs_read_folio,
+ .readahead = erofs_readahead,
+ .bmap = erofs_bmap,
+ .direct_IO = noop_direct_IO,
+ .release_folio = iomap_release_folio,
+ .invalidate_folio = iomap_invalidate_folio,
+};
+
+#ifdef CONFIG_FS_DAX
+static vm_fault_t erofs_dax_huge_fault(struct vm_fault *vmf,
+ unsigned int order)
+{
+ return dax_iomap_fault(vmf, order, NULL, NULL, &erofs_iomap_ops);
+}
+
+static vm_fault_t erofs_dax_fault(struct vm_fault *vmf)
+{
+ return erofs_dax_huge_fault(vmf, 0);
+}
+
+static const struct vm_operations_struct erofs_dax_vm_ops = {
+ .fault = erofs_dax_fault,
+ .huge_fault = erofs_dax_huge_fault,
+};
+
+static int erofs_file_mmap_prepare(struct vm_area_desc *desc)
+{
+ if (!IS_DAX(file_inode(desc->file)))
+ return generic_file_readonly_mmap_prepare(desc);
+
+ if (vma_desc_test_all(desc, VMA_SHARED_BIT, VMA_MAYWRITE_BIT))
+ return -EINVAL;
+
+ desc->vm_ops = &erofs_dax_vm_ops;
+ vma_desc_set_flags(desc, VMA_HUGEPAGE_BIT);
+ return 0;
+}
+#else
+#define erofs_file_mmap_prepare generic_file_readonly_mmap_prepare
+#endif
+
+static loff_t erofs_file_llseek(struct file *file, loff_t offset, int whence)
+{
+ struct inode *inode = file->f_mapping->host;
+ const struct iomap_ops *ops = &erofs_iomap_ops;
+
+ if (erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout)) {
+ if (!IS_ENABLED(CONFIG_EROFS_FS_ZIP))
+ return generic_file_llseek(file, offset, whence);
+ ops = &z_erofs_iomap_report_ops;
+ }
+
+ if (whence == SEEK_HOLE)
+ offset = iomap_seek_hole(inode, offset, ops);
+ else if (whence == SEEK_DATA)
+ offset = iomap_seek_data(inode, offset, ops);
+ else
+ return generic_file_llseek(file, offset, whence);
+
+ if (offset < 0)
+ return offset;
+ return vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
+}
+
+const struct file_operations erofs_file_fops = {
+ .llseek = erofs_file_llseek,
+ .read_iter = erofs_file_read_iter,
+ .unlocked_ioctl = erofs_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = erofs_compat_ioctl,
+#endif
+ .mmap_prepare = erofs_file_mmap_prepare,
+ .get_unmapped_area = thp_get_unmapped_area,
+ .splice_read = filemap_splice_read,
+ .setlease = generic_setlease,
+};
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
new file mode 100644
index 000000000..27caf4beb
--- /dev/null
+++ b/fs/erofs/decompressor.c
@@ -0,0 +1,517 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2019 HUAWEI, Inc.
+ * https://www.huawei.com/
+ * Copyright (C) 2024 Alibaba Cloud
+ */
+#include "compress.h"
+#include <linux/lz4.h>
+
+#define LZ4_MAX_DISTANCE_PAGES (DIV_ROUND_UP(LZ4_DISTANCE_MAX, PAGE_SIZE) + 1)
+
+static int z_erofs_load_lz4_config(struct super_block *sb,
+ struct erofs_super_block *dsb, void *data, int size)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ struct z_erofs_lz4_cfgs *lz4 = data;
+ u16 distance;
+
+ if (lz4) {
+ if (size < sizeof(struct z_erofs_lz4_cfgs)) {
+ erofs_err(sb, "invalid lz4 cfgs, size=%u", size);
+ return -EINVAL;
+ }
+ distance = le16_to_cpu(lz4->max_distance);
+
+ sbi->lz4.max_pclusterblks = le16_to_cpu(lz4->max_pclusterblks);
+ if (!sbi->lz4.max_pclusterblks) {
+ sbi->lz4.max_pclusterblks = 1; /* reserved case */
+ } else if (sbi->lz4.max_pclusterblks >
+ erofs_blknr(sb, Z_EROFS_PCLUSTER_MAX_SIZE)) {
+ erofs_err(sb, "too large lz4 pclusterblks %u",
+ sbi->lz4.max_pclusterblks);
+ return -EINVAL;
+ }
+ } else {
+ distance = le16_to_cpu(dsb->u1.lz4_max_distance);
+ if (!distance && !erofs_sb_has_lz4_0padding(sbi))
+ return 0;
+ sbi->lz4.max_pclusterblks = 1;
+ sbi->available_compr_algs = 1 << Z_EROFS_COMPRESSION_LZ4;
+ }
+
+ sbi->lz4.max_distance_pages = distance ?
+ DIV_ROUND_UP(distance, PAGE_SIZE) + 1 :
+ LZ4_MAX_DISTANCE_PAGES;
+ return z_erofs_gbuf_growsize(sbi->lz4.max_pclusterblks);
+}
+
+/*
+ * Fill all gaps with bounce pages if it's a sparse page list. Also check if
+ * all physical pages are consecutive, which can be seen for moderate CR.
+ */
+static int z_erofs_lz4_prepare_dstpages(struct z_erofs_decompress_req *rq,
+ struct page **pagepool)
+{
+ struct page *availables[LZ4_MAX_DISTANCE_PAGES] = { NULL };
+ unsigned long bounced[DIV_ROUND_UP(LZ4_MAX_DISTANCE_PAGES,
+ BITS_PER_LONG)] = { 0 };
+ unsigned int lz4_max_distance_pages =
+ EROFS_SB(rq->sb)->lz4.max_distance_pages;
+ void *kaddr = NULL;
+ unsigned int i, j, top;
+
+ top = 0;
+ for (i = j = 0; i < rq->outpages; ++i, ++j) {
+ struct page *const page = rq->out[i];
+ struct page *victim;
+
+ if (j >= lz4_max_distance_pages)
+ j = 0;
+
+ /* 'valid' bounced can only be tested after a complete round */
+ if (!rq->fillgaps && test_bit(j, bounced)) {
+ DBG_BUGON(i < lz4_max_distance_pages);
+ DBG_BUGON(top >= lz4_max_distance_pages);
+ availables[top++] = rq->out[i - lz4_max_distance_pages];
+ }
+
+ if (page) {
+ __clear_bit(j, bounced);
+ if (!PageHighMem(page)) {
+ if (!i) {
+ kaddr = page_address(page);
+ continue;
+ }
+ if (kaddr &&
+ kaddr + PAGE_SIZE == page_address(page)) {
+ kaddr += PAGE_SIZE;
+ continue;
+ }
+ }
+ kaddr = NULL;
+ continue;
+ }
+ kaddr = NULL;
+ __set_bit(j, bounced);
+
+ if (top) {
+ victim = availables[--top];
+ } else {
+ victim = __erofs_allocpage(pagepool, rq->gfp, true);
+ if (!victim)
+ return -ENOMEM;
+ set_page_private(victim, Z_EROFS_SHORTLIVED_PAGE);
+ }
+ rq->out[i] = victim;
+ }
+ return kaddr ? 1 : 0;
+}
+
+static void *z_erofs_lz4_handle_overlap(const struct z_erofs_decompress_req *rq,
+ void *inpage, void *out, unsigned int *inputmargin,
+ int *maptype, bool may_inplace)
+{
+ unsigned int oend, omargin, cnt, i;
+ struct page **in;
+ void *src;
+
+ /*
+ * If in-place I/O isn't used, for example, the bounce compressed cache
+ * can hold data for incomplete read requests. Just map the compressed
+ * buffer as well and decompress directly.
+ */
+ if (!rq->inplace_io) {
+ if (rq->inpages <= 1) {
+ *maptype = 0;
+ return inpage;
+ }
+ kunmap_local(inpage);
+ src = erofs_vm_map_ram(rq->in, rq->inpages);
+ if (!src)
+ return ERR_PTR(-ENOMEM);
+ *maptype = 1;
+ return src;
+ }
+ /*
+ * Then, deal with in-place I/Os. The reasons why in-place I/O is useful
+ * are: (1) It minimizes memory footprint during the I/O submission,
+ * which is useful for slow storage (including network devices and
+ * low-end HDDs/eMMCs) but with a lot inflight I/Os; (2) If in-place
+ * decompression can also be applied, it will reuse the unique buffer so
+ * that no extra CPU D-cache is polluted with temporary compressed data
+ * for extreme performance.
+ */
+ oend = rq->pageofs_out + rq->outputsize;
+ omargin = PAGE_ALIGN(oend) - oend;
+ if (!rq->partial_decoding && may_inplace &&
+ omargin >= LZ4_DECOMPRESS_INPLACE_MARGIN(rq->inputsize)) {
+ for (i = 0; i < rq->inpages; ++i)
+ if (rq->out[rq->outpages - rq->inpages + i] !=
+ rq->in[i])
+ break;
+ if (i >= rq->inpages) {
+ kunmap_local(inpage);
+ *maptype = 3;
+ return out + ((rq->outpages - rq->inpages) << PAGE_SHIFT);
+ }
+ }
+ /*
+ * If in-place decompression can't be applied, copy compressed data that
+ * may potentially overlap during decompression to a per-CPU buffer.
+ */
+ src = z_erofs_get_gbuf(rq->inpages);
+ if (!src) {
+ DBG_BUGON(1);
+ kunmap_local(inpage);
+ return ERR_PTR(-EFAULT);
+ }
+
+ for (i = 0, in = rq->in; i < rq->inputsize; i += cnt, ++in) {
+ cnt = min_t(u32, rq->inputsize - i, PAGE_SIZE - *inputmargin);
+ if (!inpage)
+ inpage = kmap_local_page(*in);
+ memcpy(src + i, inpage + *inputmargin, cnt);
+ kunmap_local(inpage);
+ inpage = NULL;
+ *inputmargin = 0;
+ }
+ *maptype = 2;
+ return src;
+}
+
+/*
+ * Get the exact on-disk size of the compressed data:
+ * - For LZ4, it should apply if the zero_padding feature is on (5.3+);
+ * - For others, zero_padding is enabled all the time.
+ */
+const char *z_erofs_fixup_insize(struct z_erofs_decompress_req *rq,
+ const char *padbuf, unsigned int padbufsize)
+{
+ const char *padend;
+
+ padend = memchr_inv(padbuf, 0, padbufsize);
+ if (!padend)
+ return "compressed data start not found";
+ rq->inputsize -= padend - padbuf;
+ rq->pageofs_in += padend - padbuf;
+ return NULL;
+}
+
+static const char *__z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq,
+ u8 *dst)
+{
+ bool may_inplace = false;
+ unsigned int inputmargin;
+ u8 *out, *headpage, *src;
+ const char *reason;
+ int ret, maptype;
+
+ headpage = kmap_local_page(*rq->in);
+ reason = z_erofs_fixup_insize(rq, headpage + rq->pageofs_in,
+ min_t(unsigned int, rq->inputsize,
+ rq->sb->s_blocksize - rq->pageofs_in));
+ if (reason) {
+ kunmap_local(headpage);
+ return reason;
+ }
+ may_inplace = !((rq->pageofs_in + rq->inputsize) &
+ (rq->sb->s_blocksize - 1));
+
+ inputmargin = rq->pageofs_in;
+ src = z_erofs_lz4_handle_overlap(rq, headpage, dst, &inputmargin,
+ &maptype, may_inplace);
+ if (IS_ERR(src))
+ return ERR_CAST(src);
+
+ out = dst + rq->pageofs_out;
+ if (rq->partial_decoding)
+ ret = LZ4_decompress_safe_partial(src + inputmargin, out,
+ rq->inputsize, rq->outputsize, rq->outputsize);
+ else
+ ret = LZ4_decompress_safe(src + inputmargin, out,
+ rq->inputsize, rq->outputsize);
+ if (ret == rq->outputsize)
+ reason = NULL;
+ else if (ret < 0)
+ reason = "corrupted compressed data";
+ else
+ reason = "unexpected end of stream";
+
+ if (!maptype) {
+ kunmap_local(headpage);
+ } else if (maptype == 1) {
+ vm_unmap_ram(src, rq->inpages);
+ } else if (maptype == 2) {
+ z_erofs_put_gbuf(src);
+ } else if (maptype != 3) {
+ DBG_BUGON(1);
+ return ERR_PTR(-EFAULT);
+ }
+ return reason;
+}
+
+static const char *z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq,
+ struct page **pagepool)
+{
+ unsigned int dst_maptype;
+ const char *reason;
+ void *dst;
+ int ret;
+
+ /* one optimized fast path only for non bigpcluster cases yet */
+ if (rq->inpages == 1 && rq->outpages == 1 && !rq->inplace_io) {
+ DBG_BUGON(!*rq->out);
+ dst = kmap_local_page(*rq->out);
+ dst_maptype = 0;
+ } else {
+ /* general decoding path which can be used for all cases */
+ ret = z_erofs_lz4_prepare_dstpages(rq, pagepool);
+ if (ret < 0)
+ return ERR_PTR(ret);
+ if (ret > 0) {
+ dst = page_address(*rq->out);
+ dst_maptype = 1;
+ } else {
+ dst = erofs_vm_map_ram(rq->out, rq->outpages);
+ if (!dst)
+ return ERR_PTR(-ENOMEM);
+ dst_maptype = 2;
+ }
+ }
+ reason = __z_erofs_lz4_decompress(rq, dst);
+ if (!dst_maptype)
+ kunmap_local(dst);
+ else if (dst_maptype == 2)
+ vm_unmap_ram(dst, rq->outpages);
+ return reason;
+}
+
+static const char *z_erofs_transform_plain(struct z_erofs_decompress_req *rq,
+ struct page **pagepool)
+{
+ const unsigned int nrpages_in = rq->inpages, nrpages_out = rq->outpages;
+ const unsigned int bs = rq->sb->s_blocksize;
+ unsigned int cur = 0, ni = 0, no, pi, po, insz, cnt;
+ u8 *kin;
+
+ if (rq->outputsize > rq->inputsize)
+ return ERR_PTR(-EOPNOTSUPP);
+ if (rq->alg == Z_EROFS_COMPRESSION_INTERLACED) {
+ cur = bs - (rq->pageofs_out & (bs - 1));
+ DBG_BUGON(rq->pageofs_in & (bs - 1));
+ pi = (rq->pageofs_in + rq->inputsize - cur) & ~PAGE_MASK;
+ cur = min(cur, rq->outputsize);
+ if (cur && rq->out[0]) {
+ kin = kmap_local_page(rq->in[nrpages_in - 1]);
+ if (rq->out[0] == rq->in[nrpages_in - 1])
+ memmove(kin + rq->pageofs_out, kin + pi, cur);
+ else
+ memcpy_to_page(rq->out[0], rq->pageofs_out,
+ kin + pi, cur);
+ kunmap_local(kin);
+ }
+ rq->outputsize -= cur;
+ }
+
+ for (; rq->outputsize; rq->pageofs_in = 0, cur += insz, ni++) {
+ insz = min(PAGE_SIZE - rq->pageofs_in, rq->outputsize);
+ rq->outputsize -= insz;
+ if (!rq->in[ni])
+ continue;
+ kin = kmap_local_page(rq->in[ni]);
+ pi = 0;
+ do {
+ no = (rq->pageofs_out + cur + pi) >> PAGE_SHIFT;
+ po = (rq->pageofs_out + cur + pi) & ~PAGE_MASK;
+ DBG_BUGON(no >= nrpages_out);
+ cnt = min(insz - pi, PAGE_SIZE - po);
+ if (rq->out[no] == rq->in[ni])
+ memmove(kin + po,
+ kin + rq->pageofs_in + pi, cnt);
+ else if (rq->out[no])
+ memcpy_to_page(rq->out[no], po,
+ kin + rq->pageofs_in + pi, cnt);
+ pi += cnt;
+ } while (pi < insz);
+ kunmap_local(kin);
+ }
+ DBG_BUGON(ni > nrpages_in);
+ return NULL;
+}
+
+const char *z_erofs_stream_switch_bufs(struct z_erofs_stream_dctx *dctx,
+ void **dst, void **src, struct page **pgpl)
+{
+ struct z_erofs_decompress_req *rq = dctx->rq;
+ struct page **pgo, *tmppage;
+ unsigned int j;
+
+ if (!dctx->avail_out) {
+ if (++dctx->no >= rq->outpages || !rq->outputsize)
+ return "insufficient space for decompressed data";
+
+ if (dctx->kout)
+ kunmap_local(dctx->kout);
+ dctx->avail_out = min(rq->outputsize, PAGE_SIZE - rq->pageofs_out);
+ rq->outputsize -= dctx->avail_out;
+ pgo = &rq->out[dctx->no];
+ if (!*pgo && rq->fillgaps) { /* deduped */
+ *pgo = erofs_allocpage(pgpl, rq->gfp);
+ if (!*pgo) {
+ dctx->kout = NULL;
+ return ERR_PTR(-ENOMEM);
+ }
+ set_page_private(*pgo, Z_EROFS_SHORTLIVED_PAGE);
+ }
+ if (*pgo) {
+ dctx->kout = kmap_local_page(*pgo);
+ *dst = dctx->kout + rq->pageofs_out;
+ } else {
+ *dst = dctx->kout = NULL;
+ }
+ rq->pageofs_out = 0;
+ }
+
+ if (dctx->inbuf_pos == dctx->inbuf_sz && rq->inputsize) {
+ if (++dctx->ni >= rq->inpages)
+ return "invalid compressed data";
+ if (dctx->kout) /* unlike kmap(), take care of the orders */
+ kunmap_local(dctx->kout);
+ kunmap_local(dctx->kin);
+
+ dctx->inbuf_sz = min_t(u32, rq->inputsize, PAGE_SIZE);
+ rq->inputsize -= dctx->inbuf_sz;
+ dctx->kin = kmap_local_page(rq->in[dctx->ni]);
+ *src = dctx->kin;
+ dctx->bounced = false;
+ if (dctx->kout) {
+ j = (u8 *)*dst - dctx->kout;
+ dctx->kout = kmap_local_page(rq->out[dctx->no]);
+ *dst = dctx->kout + j;
+ }
+ dctx->inbuf_pos = 0;
+ }
+
+ /*
+ * Handle overlapping: Use the given bounce buffer if the input data is
+ * under processing; Or utilize short-lived pages from the on-stack page
+ * pool, where pages are shared among the same request. Note that only
+ * a few inplace I/O pages need to be doubled.
+ */
+ if (!dctx->bounced && rq->out[dctx->no] == rq->in[dctx->ni]) {
+ memcpy(dctx->bounce, *src, dctx->inbuf_sz);
+ *src = dctx->bounce;
+ dctx->bounced = true;
+ }
+
+ for (j = dctx->ni + 1; j < rq->inpages; ++j) {
+ if (rq->out[dctx->no] != rq->in[j])
+ continue;
+ tmppage = erofs_allocpage(pgpl, rq->gfp);
+ if (!tmppage)
+ return ERR_PTR(-ENOMEM);
+ set_page_private(tmppage, Z_EROFS_SHORTLIVED_PAGE);
+ copy_highpage(tmppage, rq->in[j]);
+ rq->in[j] = tmppage;
+ }
+ return NULL;
+}
+
+const struct z_erofs_decompressor *z_erofs_decomp[] = {
+ [Z_EROFS_COMPRESSION_SHIFTED] = &(const struct z_erofs_decompressor) {
+ .decompress = z_erofs_transform_plain,
+ .name = "shifted"
+ },
+ [Z_EROFS_COMPRESSION_INTERLACED] = &(const struct z_erofs_decompressor) {
+ .decompress = z_erofs_transform_plain,
+ .name = "interlaced"
+ },
+ [Z_EROFS_COMPRESSION_LZ4] = &(const struct z_erofs_decompressor) {
+ .config = z_erofs_load_lz4_config,
+ .decompress = z_erofs_lz4_decompress,
+ .init = z_erofs_gbuf_init,
+ .exit = z_erofs_gbuf_exit,
+ .name = "lz4"
+ },
+#ifdef CONFIG_EROFS_FS_ZIP_LZMA
+ [Z_EROFS_COMPRESSION_LZMA] = &z_erofs_lzma_decomp,
+#endif
+#ifdef CONFIG_EROFS_FS_ZIP_DEFLATE
+ [Z_EROFS_COMPRESSION_DEFLATE] = &z_erofs_deflate_decomp,
+#endif
+#ifdef CONFIG_EROFS_FS_ZIP_ZSTD
+ [Z_EROFS_COMPRESSION_ZSTD] = &z_erofs_zstd_decomp,
+#endif
+};
+
+int z_erofs_parse_cfgs(struct super_block *sb, struct erofs_super_block *dsb)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+ unsigned long algs, alg;
+ erofs_off_t offset;
+ int size, ret = 0;
+
+ if (!erofs_sb_has_compr_cfgs(sbi))
+ return z_erofs_load_lz4_config(sb, dsb, NULL, 0);
+
+ algs = le16_to_cpu(dsb->u1.available_compr_algs);
+ sbi->available_compr_algs = algs;
+ if (algs & ~Z_EROFS_ALL_COMPR_ALGS) {
+ erofs_err(sb, "unidentified algorithms %lx, please upgrade kernel",
+ algs & ~Z_EROFS_ALL_COMPR_ALGS);
+ return -EOPNOTSUPP;
+ }
+
+ (void)erofs_init_metabuf(&buf, sb, false);
+ offset = EROFS_SUPER_OFFSET + sbi->sb_size;
+ for_each_set_bit(alg, &algs, Z_EROFS_COMPRESSION_MAX) {
+ const struct z_erofs_decompressor *dec = z_erofs_decomp[alg];
+ void *data;
+
+ data = erofs_read_metadata(sb, &buf, &offset, &size);
+ if (IS_ERR(data)) {
+ ret = PTR_ERR(data);
+ break;
+ }
+
+ if (dec && dec->config) {
+ ret = dec->config(sb, dsb, data, size);
+ } else {
+ erofs_err(sb, "algorithm %ld isn't enabled on this kernel",
+ alg);
+ ret = -EOPNOTSUPP;
+ }
+ kfree(data);
+ if (ret)
+ break;
+ }
+ erofs_put_metabuf(&buf);
+ return ret;
+}
+
+int __init z_erofs_init_decompressor(void)
+{
+ int i, err;
+
+ for (i = 0; i < Z_EROFS_COMPRESSION_MAX; ++i) {
+ err = z_erofs_decomp[i] ? z_erofs_decomp[i]->init() : 0;
+ if (err) {
+ while (i--)
+ if (z_erofs_decomp[i])
+ z_erofs_decomp[i]->exit();
+ return err;
+ }
+ }
+ return 0;
+}
+
+void z_erofs_exit_decompressor(void)
+{
+ int i;
+
+ for (i = 0; i < Z_EROFS_COMPRESSION_MAX; ++i)
+ if (z_erofs_decomp[i])
+ z_erofs_decomp[i]->exit();
+}
diff --git a/fs/erofs/decompressor_crypto.c b/fs/erofs/decompressor_crypto.c
new file mode 100644
index 000000000..77c6bd535
--- /dev/null
+++ b/fs/erofs/decompressor_crypto.c
@@ -0,0 +1,182 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/scatterlist.h>
+#include <crypto/acompress.h>
+#include "compress.h"
+
+static int __z_erofs_crypto_decompress(struct z_erofs_decompress_req *rq,
+ struct crypto_acomp *tfm)
+{
+ struct sg_table st_src, st_dst;
+ struct acomp_req *req;
+ struct crypto_wait wait;
+ const char *reason;
+ u8 *headpage;
+ int ret;
+
+ headpage = kmap_local_page(*rq->in);
+ reason = z_erofs_fixup_insize(rq, headpage + rq->pageofs_in,
+ min_t(unsigned int, rq->inputsize,
+ rq->sb->s_blocksize - rq->pageofs_in));
+ kunmap_local(headpage);
+ if (reason)
+ return IS_ERR(reason) ? PTR_ERR(reason) : -EFSCORRUPTED;
+
+ req = acomp_request_alloc(tfm);
+ if (!req)
+ return -ENOMEM;
+
+ ret = sg_alloc_table_from_pages_segment(&st_src, rq->in, rq->inpages,
+ rq->pageofs_in, rq->inputsize, UINT_MAX, GFP_KERNEL);
+ if (ret < 0)
+ goto failed_src_alloc;
+
+ ret = sg_alloc_table_from_pages_segment(&st_dst, rq->out, rq->outpages,
+ rq->pageofs_out, rq->outputsize, UINT_MAX, GFP_KERNEL);
+ if (ret < 0)
+ goto failed_dst_alloc;
+
+ acomp_request_set_params(req, st_src.sgl,
+ st_dst.sgl, rq->inputsize, rq->outputsize);
+
+ crypto_init_wait(&wait);
+ acomp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+ crypto_req_done, &wait);
+
+ ret = crypto_wait_req(crypto_acomp_decompress(req), &wait);
+ if (ret) {
+ erofs_err(rq->sb, "failed to decompress %d in[%u, %u] out[%u]",
+ ret, rq->inputsize, rq->pageofs_in, rq->outputsize);
+ ret = -EIO;
+ }
+
+ sg_free_table(&st_dst);
+failed_dst_alloc:
+ sg_free_table(&st_src);
+failed_src_alloc:
+ acomp_request_free(req);
+ return ret;
+}
+
+struct z_erofs_crypto_engine {
+ char *crypto_name;
+ struct crypto_acomp *tfm;
+};
+
+static struct z_erofs_crypto_engine *z_erofs_crypto[Z_EROFS_COMPRESSION_MAX] = {
+ [Z_EROFS_COMPRESSION_LZ4] = (struct z_erofs_crypto_engine[]) {
+ {},
+ },
+ [Z_EROFS_COMPRESSION_LZMA] = (struct z_erofs_crypto_engine[]) {
+ {},
+ },
+ [Z_EROFS_COMPRESSION_DEFLATE] = (struct z_erofs_crypto_engine[]) {
+ { .crypto_name = "qat_deflate", },
+ {},
+ },
+ [Z_EROFS_COMPRESSION_ZSTD] = (struct z_erofs_crypto_engine[]) {
+ {},
+ },
+};
+static DECLARE_RWSEM(z_erofs_crypto_rwsem);
+
+static struct crypto_acomp *z_erofs_crypto_get_engine(int alg)
+{
+ struct z_erofs_crypto_engine *e;
+
+ for (e = z_erofs_crypto[alg]; e->crypto_name; ++e)
+ if (e->tfm)
+ return e->tfm;
+ return NULL;
+}
+
+int z_erofs_crypto_decompress(struct z_erofs_decompress_req *rq,
+ struct page **pgpl)
+{
+ struct crypto_acomp *tfm;
+ int i, err;
+
+ down_read(&z_erofs_crypto_rwsem);
+ tfm = z_erofs_crypto_get_engine(rq->alg);
+ if (!tfm) {
+ err = -EOPNOTSUPP;
+ goto out;
+ }
+
+ for (i = 0; i < rq->outpages; i++) {
+ struct page *const page = rq->out[i];
+ struct page *victim;
+
+ if (!page) {
+ victim = __erofs_allocpage(pgpl, rq->gfp, true);
+ if (!victim) {
+ err = -ENOMEM;
+ goto out;
+ }
+ set_page_private(victim, Z_EROFS_SHORTLIVED_PAGE);
+ rq->out[i] = victim;
+ }
+ }
+ err = __z_erofs_crypto_decompress(rq, tfm);
+out:
+ up_read(&z_erofs_crypto_rwsem);
+ return err;
+}
+
+int z_erofs_crypto_enable_engine(const char *name, int len)
+{
+ struct z_erofs_crypto_engine *e;
+ struct crypto_acomp *tfm;
+ int alg;
+
+ down_write(&z_erofs_crypto_rwsem);
+ for (alg = 0; alg < Z_EROFS_COMPRESSION_MAX; ++alg) {
+ for (e = z_erofs_crypto[alg]; e->crypto_name; ++e) {
+ if (!strncmp(name, e->crypto_name, len)) {
+ if (e->tfm)
+ break;
+ tfm = crypto_alloc_acomp(e->crypto_name, 0, 0);
+ if (IS_ERR(tfm)) {
+ up_write(&z_erofs_crypto_rwsem);
+ return -EOPNOTSUPP;
+ }
+ e->tfm = tfm;
+ break;
+ }
+ }
+ }
+ up_write(&z_erofs_crypto_rwsem);
+ return 0;
+}
+
+void z_erofs_crypto_disable_all_engines(void)
+{
+ struct z_erofs_crypto_engine *e;
+ int alg;
+
+ down_write(&z_erofs_crypto_rwsem);
+ for (alg = 0; alg < Z_EROFS_COMPRESSION_MAX; ++alg) {
+ for (e = z_erofs_crypto[alg]; e->crypto_name; ++e) {
+ if (!e->tfm)
+ continue;
+ crypto_free_acomp(e->tfm);
+ e->tfm = NULL;
+ }
+ }
+ up_write(&z_erofs_crypto_rwsem);
+}
+
+int z_erofs_crypto_show_engines(char *buf, int size, char sep)
+{
+ struct z_erofs_crypto_engine *e;
+ int alg, len = 0;
+
+ for (alg = 0; alg < Z_EROFS_COMPRESSION_MAX; ++alg) {
+ for (e = z_erofs_crypto[alg]; e->crypto_name; ++e) {
+ if (!e->tfm)
+ continue;
+ len += scnprintf(buf + len, size - len, "%s%c",
+ e->crypto_name, sep);
+ }
+ }
+ return len;
+}
diff --git a/fs/erofs/decompressor_deflate.c b/fs/erofs/decompressor_deflate.c
new file mode 100644
index 000000000..6167af1ff
--- /dev/null
+++ b/fs/erofs/decompressor_deflate.c
@@ -0,0 +1,203 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/zlib.h>
+#include "compress.h"
+
+struct z_erofs_deflate {
+ struct z_erofs_deflate *next;
+ struct z_stream_s z;
+ u8 bounce[PAGE_SIZE];
+};
+
+static DEFINE_SPINLOCK(z_erofs_deflate_lock);
+static unsigned int z_erofs_deflate_nstrms, z_erofs_deflate_avail_strms;
+static struct z_erofs_deflate *z_erofs_deflate_head;
+static DECLARE_WAIT_QUEUE_HEAD(z_erofs_deflate_wq);
+
+module_param_named(deflate_streams, z_erofs_deflate_nstrms, uint, 0444);
+
+static void z_erofs_deflate_exit(void)
+{
+ /* there should be no running fs instance */
+ while (z_erofs_deflate_avail_strms) {
+ struct z_erofs_deflate *strm;
+
+ spin_lock(&z_erofs_deflate_lock);
+ strm = z_erofs_deflate_head;
+ if (!strm) {
+ spin_unlock(&z_erofs_deflate_lock);
+ continue;
+ }
+ z_erofs_deflate_head = NULL;
+ spin_unlock(&z_erofs_deflate_lock);
+
+ while (strm) {
+ struct z_erofs_deflate *n = strm->next;
+
+ vfree(strm->z.workspace);
+ kfree(strm);
+ --z_erofs_deflate_avail_strms;
+ strm = n;
+ }
+ }
+}
+
+static int __init z_erofs_deflate_init(void)
+{
+ /* by default, use # of possible CPUs instead */
+ if (!z_erofs_deflate_nstrms)
+ z_erofs_deflate_nstrms = num_possible_cpus();
+ return 0;
+}
+
+static int z_erofs_load_deflate_config(struct super_block *sb,
+ struct erofs_super_block *dsb, void *data, int size)
+{
+ struct z_erofs_deflate_cfgs *dfl = data;
+ static DEFINE_MUTEX(deflate_resize_mutex);
+ static bool inited;
+
+ if (!dfl || size < sizeof(struct z_erofs_deflate_cfgs)) {
+ erofs_err(sb, "invalid deflate cfgs, size=%u", size);
+ return -EINVAL;
+ }
+
+ if (dfl->windowbits > MAX_WBITS) {
+ erofs_err(sb, "unsupported windowbits %u", dfl->windowbits);
+ return -EOPNOTSUPP;
+ }
+ mutex_lock(&deflate_resize_mutex);
+ if (!inited) {
+ for (; z_erofs_deflate_avail_strms < z_erofs_deflate_nstrms;
+ ++z_erofs_deflate_avail_strms) {
+ struct z_erofs_deflate *strm;
+
+ strm = kzalloc_obj(*strm);
+ if (!strm)
+ goto failed;
+ /* XXX: in-kernel zlib cannot customize windowbits */
+ strm->z.workspace = vmalloc(zlib_inflate_workspacesize());
+ if (!strm->z.workspace) {
+ kfree(strm);
+ goto failed;
+ }
+
+ spin_lock(&z_erofs_deflate_lock);
+ strm->next = z_erofs_deflate_head;
+ z_erofs_deflate_head = strm;
+ spin_unlock(&z_erofs_deflate_lock);
+ }
+ inited = true;
+ }
+ mutex_unlock(&deflate_resize_mutex);
+ return 0;
+failed:
+ mutex_unlock(&deflate_resize_mutex);
+ z_erofs_deflate_exit();
+ return -ENOMEM;
+}
+
+static const char *__z_erofs_deflate_decompress(struct z_erofs_decompress_req *rq,
+ struct page **pgpl)
+{
+ struct super_block *sb = rq->sb;
+ struct z_erofs_stream_dctx dctx = { .rq = rq, .no = -1, .ni = 0 };
+ struct z_erofs_deflate *strm;
+ const char *reason;
+ int zerr;
+
+ /* 1. get the exact DEFLATE compressed size */
+ dctx.kin = kmap_local_page(*rq->in);
+ reason = z_erofs_fixup_insize(rq, dctx.kin + rq->pageofs_in,
+ min(rq->inputsize, sb->s_blocksize - rq->pageofs_in));
+ if (reason) {
+ kunmap_local(dctx.kin);
+ return reason;
+ }
+
+ /* 2. get an available DEFLATE context */
+again:
+ spin_lock(&z_erofs_deflate_lock);
+ strm = z_erofs_deflate_head;
+ if (!strm) {
+ spin_unlock(&z_erofs_deflate_lock);
+ wait_event(z_erofs_deflate_wq, READ_ONCE(z_erofs_deflate_head));
+ goto again;
+ }
+ z_erofs_deflate_head = strm->next;
+ spin_unlock(&z_erofs_deflate_lock);
+
+ /* 3. multi-call decompress */
+ zerr = zlib_inflateInit2(&strm->z, -MAX_WBITS);
+ if (zerr != Z_OK) {
+ reason = ERR_PTR(-EINVAL);
+ goto failed_zinit;
+ }
+
+ rq->fillgaps = true; /* DEFLATE doesn't support NULL output buffer */
+ strm->z.avail_in = min(rq->inputsize, PAGE_SIZE - rq->pageofs_in);
+ rq->inputsize -= strm->z.avail_in;
+ strm->z.next_in = dctx.kin + rq->pageofs_in;
+ strm->z.avail_out = 0;
+ dctx.bounce = strm->bounce;
+
+ while (1) {
+ dctx.avail_out = strm->z.avail_out;
+ dctx.inbuf_sz = strm->z.avail_in;
+ reason = z_erofs_stream_switch_bufs(&dctx,
+ (void **)&strm->z.next_out,
+ (void **)&strm->z.next_in, pgpl);
+ if (reason)
+ break;
+ strm->z.avail_out = dctx.avail_out;
+ strm->z.avail_in = dctx.inbuf_sz;
+
+ zerr = zlib_inflate(&strm->z, Z_SYNC_FLUSH);
+ if (zerr != Z_OK || !(rq->outputsize + strm->z.avail_out)) {
+ if (zerr == Z_OK && rq->partial_decoding)
+ break;
+ if (zerr == Z_STREAM_END && !rq->outputsize)
+ break;
+ reason = (zerr == Z_DATA_ERROR ?
+ "corrupted compressed data" :
+ "unexpected end of stream");
+ break;
+ }
+ }
+ if (zlib_inflateEnd(&strm->z) != Z_OK && !reason)
+ reason = ERR_PTR(-EIO);
+ if (dctx.kout)
+ kunmap_local(dctx.kout);
+failed_zinit:
+ kunmap_local(dctx.kin);
+ /* 4. push back DEFLATE stream context to the global list */
+ spin_lock(&z_erofs_deflate_lock);
+ strm->next = z_erofs_deflate_head;
+ z_erofs_deflate_head = strm;
+ spin_unlock(&z_erofs_deflate_lock);
+ wake_up(&z_erofs_deflate_wq);
+ return reason;
+}
+
+static const char *z_erofs_deflate_decompress(struct z_erofs_decompress_req *rq,
+ struct page **pgpl)
+{
+#ifdef CONFIG_EROFS_FS_ZIP_ACCEL
+ int err;
+
+ if (!rq->partial_decoding) {
+ err = z_erofs_crypto_decompress(rq, pgpl);
+ if (err != -EOPNOTSUPP)
+ return ERR_PTR(err);
+
+ }
+#endif
+ return __z_erofs_deflate_decompress(rq, pgpl);
+}
+
+const struct z_erofs_decompressor z_erofs_deflate_decomp = {
+ .config = z_erofs_load_deflate_config,
+ .decompress = z_erofs_deflate_decompress,
+ .init = z_erofs_deflate_init,
+ .exit = z_erofs_deflate_exit,
+ .name = "deflate",
+};
diff --git a/fs/erofs/decompressor_lzma.c b/fs/erofs/decompressor_lzma.c
new file mode 100644
index 000000000..6b0cdb446
--- /dev/null
+++ b/fs/erofs/decompressor_lzma.c
@@ -0,0 +1,236 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/xz.h>
+#include "compress.h"
+
+struct z_erofs_lzma {
+ struct z_erofs_lzma *next;
+ struct xz_dec_microlzma *state;
+ u8 bounce[PAGE_SIZE];
+};
+
+/* considering the LZMA performance, no need to use a lockless list for now */
+static DEFINE_SPINLOCK(z_erofs_lzma_lock);
+static unsigned int z_erofs_lzma_max_dictsize;
+static unsigned int z_erofs_lzma_nstrms, z_erofs_lzma_avail_strms;
+static struct z_erofs_lzma *z_erofs_lzma_head;
+static DECLARE_WAIT_QUEUE_HEAD(z_erofs_lzma_wq);
+
+module_param_named(lzma_streams, z_erofs_lzma_nstrms, uint, 0444);
+
+static void z_erofs_lzma_exit(void)
+{
+ /* there should be no running fs instance */
+ while (z_erofs_lzma_avail_strms) {
+ struct z_erofs_lzma *strm;
+
+ spin_lock(&z_erofs_lzma_lock);
+ strm = z_erofs_lzma_head;
+ if (!strm) {
+ spin_unlock(&z_erofs_lzma_lock);
+ DBG_BUGON(1);
+ return;
+ }
+ z_erofs_lzma_head = NULL;
+ spin_unlock(&z_erofs_lzma_lock);
+
+ while (strm) {
+ struct z_erofs_lzma *n = strm->next;
+
+ if (strm->state)
+ xz_dec_microlzma_end(strm->state);
+ kfree(strm);
+ --z_erofs_lzma_avail_strms;
+ strm = n;
+ }
+ }
+}
+
+static int __init z_erofs_lzma_init(void)
+{
+ unsigned int i;
+
+ /* by default, use # of possible CPUs instead */
+ if (!z_erofs_lzma_nstrms)
+ z_erofs_lzma_nstrms = min_t(unsigned int, num_possible_cpus(),
+ CONFIG_EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS);
+
+ for (i = 0; i < z_erofs_lzma_nstrms; ++i) {
+ struct z_erofs_lzma *strm = kzalloc_obj(*strm);
+
+ if (!strm) {
+ z_erofs_lzma_exit();
+ return -ENOMEM;
+ }
+ spin_lock(&z_erofs_lzma_lock);
+ strm->next = z_erofs_lzma_head;
+ z_erofs_lzma_head = strm;
+ spin_unlock(&z_erofs_lzma_lock);
+ ++z_erofs_lzma_avail_strms;
+ }
+ return 0;
+}
+
+static int z_erofs_load_lzma_config(struct super_block *sb,
+ struct erofs_super_block *dsb, void *data, int size)
+{
+ static DEFINE_MUTEX(lzma_resize_mutex);
+ struct z_erofs_lzma_cfgs *lzma = data;
+ unsigned int dict_size, i;
+ struct z_erofs_lzma *strm, *head = NULL;
+ int err;
+
+ if (!lzma || size < sizeof(struct z_erofs_lzma_cfgs)) {
+ erofs_err(sb, "invalid lzma cfgs, size=%u", size);
+ return -EINVAL;
+ }
+ if (lzma->format) {
+ erofs_err(sb, "unidentified lzma format %x, please check kernel version",
+ le16_to_cpu(lzma->format));
+ return -EINVAL;
+ }
+ dict_size = le32_to_cpu(lzma->dict_size);
+ if (dict_size > Z_EROFS_LZMA_MAX_DICT_SIZE || dict_size < 4096) {
+ erofs_err(sb, "unsupported lzma dictionary size %u",
+ dict_size);
+ return -EINVAL;
+ }
+
+ /* in case 2 z_erofs_load_lzma_config() race to avoid deadlock */
+ mutex_lock(&lzma_resize_mutex);
+
+ if (z_erofs_lzma_max_dictsize >= dict_size) {
+ mutex_unlock(&lzma_resize_mutex);
+ return 0;
+ }
+
+ /* 1. collect/isolate all streams for the following check */
+ for (i = 0; i < z_erofs_lzma_avail_strms; ++i) {
+ struct z_erofs_lzma *last;
+
+again:
+ spin_lock(&z_erofs_lzma_lock);
+ strm = z_erofs_lzma_head;
+ if (!strm) {
+ spin_unlock(&z_erofs_lzma_lock);
+ wait_event(z_erofs_lzma_wq,
+ READ_ONCE(z_erofs_lzma_head));
+ goto again;
+ }
+ z_erofs_lzma_head = NULL;
+ spin_unlock(&z_erofs_lzma_lock);
+
+ for (last = strm; last->next; last = last->next)
+ ++i;
+ last->next = head;
+ head = strm;
+ }
+
+ err = 0;
+ /* 2. walk each isolated stream and grow max dict_size if needed */
+ for (strm = head; strm; strm = strm->next) {
+ if (strm->state)
+ xz_dec_microlzma_end(strm->state);
+ strm->state = xz_dec_microlzma_alloc(XZ_PREALLOC, dict_size);
+ if (!strm->state)
+ err = -ENOMEM;
+ }
+
+ /* 3. push back all to the global list and update max dict_size */
+ spin_lock(&z_erofs_lzma_lock);
+ DBG_BUGON(z_erofs_lzma_head);
+ z_erofs_lzma_head = head;
+ spin_unlock(&z_erofs_lzma_lock);
+ wake_up_all(&z_erofs_lzma_wq);
+
+ z_erofs_lzma_max_dictsize = dict_size;
+ mutex_unlock(&lzma_resize_mutex);
+ return err;
+}
+
+static const char *z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq,
+ struct page **pgpl)
+{
+ struct super_block *sb = rq->sb;
+ struct z_erofs_stream_dctx dctx = { .rq = rq, .no = -1, .ni = 0 };
+ struct xz_buf buf = {};
+ struct z_erofs_lzma *strm;
+ enum xz_ret xz_err;
+ const char *reason;
+
+ /* 1. get the exact LZMA compressed size */
+ dctx.kin = kmap_local_page(*rq->in);
+ reason = z_erofs_fixup_insize(rq, dctx.kin + rq->pageofs_in,
+ min(rq->inputsize, sb->s_blocksize - rq->pageofs_in));
+ if (reason) {
+ kunmap_local(dctx.kin);
+ return reason;
+ }
+
+ /* 2. get an available lzma context */
+again:
+ spin_lock(&z_erofs_lzma_lock);
+ strm = z_erofs_lzma_head;
+ if (!strm) {
+ spin_unlock(&z_erofs_lzma_lock);
+ wait_event(z_erofs_lzma_wq, READ_ONCE(z_erofs_lzma_head));
+ goto again;
+ }
+ z_erofs_lzma_head = strm->next;
+ spin_unlock(&z_erofs_lzma_lock);
+
+ /* 3. multi-call decompress */
+ xz_dec_microlzma_reset(strm->state, rq->inputsize, rq->outputsize,
+ !rq->partial_decoding);
+ buf.in_size = min(rq->inputsize, PAGE_SIZE - rq->pageofs_in);
+ rq->inputsize -= buf.in_size;
+ buf.in = dctx.kin + rq->pageofs_in;
+ dctx.bounce = strm->bounce;
+ do {
+ dctx.avail_out = buf.out_size - buf.out_pos;
+ dctx.inbuf_sz = buf.in_size;
+ dctx.inbuf_pos = buf.in_pos;
+ reason = z_erofs_stream_switch_bufs(&dctx, (void **)&buf.out,
+ (void **)&buf.in, pgpl);
+ if (reason)
+ break;
+
+ if (buf.out_size == buf.out_pos) {
+ buf.out_size = dctx.avail_out;
+ buf.out_pos = 0;
+ }
+ buf.in_size = dctx.inbuf_sz;
+ buf.in_pos = dctx.inbuf_pos;
+
+ xz_err = xz_dec_microlzma_run(strm->state, &buf);
+ DBG_BUGON(buf.out_pos > buf.out_size);
+ DBG_BUGON(buf.in_pos > buf.in_size);
+
+ if (xz_err != XZ_OK) {
+ if (xz_err == XZ_STREAM_END && !rq->outputsize)
+ break;
+ reason = (xz_err == XZ_DATA_ERROR ?
+ "corrupted compressed data" :
+ "unexpected end of stream");
+ break;
+ }
+ } while (1);
+
+ if (dctx.kout)
+ kunmap_local(dctx.kout);
+ kunmap_local(dctx.kin);
+ /* 4. push back LZMA stream context to the global list */
+ spin_lock(&z_erofs_lzma_lock);
+ strm->next = z_erofs_lzma_head;
+ z_erofs_lzma_head = strm;
+ spin_unlock(&z_erofs_lzma_lock);
+ wake_up(&z_erofs_lzma_wq);
+ return reason;
+}
+
+const struct z_erofs_decompressor z_erofs_lzma_decomp = {
+ .config = z_erofs_load_lzma_config,
+ .decompress = z_erofs_lzma_decompress,
+ .init = z_erofs_lzma_init,
+ .exit = z_erofs_lzma_exit,
+ .name = "lzma"
+};
diff --git a/fs/erofs/decompressor_zstd.c b/fs/erofs/decompressor_zstd.c
new file mode 100644
index 000000000..ab318a240
--- /dev/null
+++ b/fs/erofs/decompressor_zstd.c
@@ -0,0 +1,220 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/zstd.h>
+#include "compress.h"
+
+struct z_erofs_zstd {
+ struct z_erofs_zstd *next;
+ u8 bounce[PAGE_SIZE];
+ void *wksp;
+ unsigned int wkspsz;
+};
+
+static DEFINE_SPINLOCK(z_erofs_zstd_lock);
+static unsigned int z_erofs_zstd_max_dictsize;
+static unsigned int z_erofs_zstd_nstrms, z_erofs_zstd_avail_strms;
+static struct z_erofs_zstd *z_erofs_zstd_head;
+static DECLARE_WAIT_QUEUE_HEAD(z_erofs_zstd_wq);
+
+module_param_named(zstd_streams, z_erofs_zstd_nstrms, uint, 0444);
+
+static struct z_erofs_zstd *z_erofs_isolate_strms(bool all)
+{
+ struct z_erofs_zstd *strm;
+
+again:
+ spin_lock(&z_erofs_zstd_lock);
+ strm = z_erofs_zstd_head;
+ if (!strm) {
+ spin_unlock(&z_erofs_zstd_lock);
+ wait_event(z_erofs_zstd_wq, READ_ONCE(z_erofs_zstd_head));
+ goto again;
+ }
+ z_erofs_zstd_head = all ? NULL : strm->next;
+ spin_unlock(&z_erofs_zstd_lock);
+ return strm;
+}
+
+static void z_erofs_zstd_exit(void)
+{
+ while (z_erofs_zstd_avail_strms) {
+ struct z_erofs_zstd *strm, *n;
+
+ for (strm = z_erofs_isolate_strms(true); strm; strm = n) {
+ n = strm->next;
+
+ kvfree(strm->wksp);
+ kfree(strm);
+ --z_erofs_zstd_avail_strms;
+ }
+ }
+}
+
+static int __init z_erofs_zstd_init(void)
+{
+ /* by default, use # of possible CPUs instead */
+ if (!z_erofs_zstd_nstrms)
+ z_erofs_zstd_nstrms = num_possible_cpus();
+
+ for (; z_erofs_zstd_avail_strms < z_erofs_zstd_nstrms;
+ ++z_erofs_zstd_avail_strms) {
+ struct z_erofs_zstd *strm;
+
+ strm = kzalloc_obj(*strm);
+ if (!strm) {
+ z_erofs_zstd_exit();
+ return -ENOMEM;
+ }
+ spin_lock(&z_erofs_zstd_lock);
+ strm->next = z_erofs_zstd_head;
+ z_erofs_zstd_head = strm;
+ spin_unlock(&z_erofs_zstd_lock);
+ }
+ return 0;
+}
+
+static int z_erofs_load_zstd_config(struct super_block *sb,
+ struct erofs_super_block *dsb, void *data, int size)
+{
+ static DEFINE_MUTEX(zstd_resize_mutex);
+ struct z_erofs_zstd_cfgs *zstd = data;
+ unsigned int dict_size, wkspsz;
+ struct z_erofs_zstd *strm, *head = NULL;
+ void *wksp;
+
+ if (!zstd || size < sizeof(struct z_erofs_zstd_cfgs) || zstd->format) {
+ erofs_err(sb, "unsupported zstd format, size=%u", size);
+ return -EINVAL;
+ }
+
+ if (zstd->windowlog > ilog2(Z_EROFS_ZSTD_MAX_DICT_SIZE) - 10) {
+ erofs_err(sb, "unsupported zstd window log %u", zstd->windowlog);
+ return -EINVAL;
+ }
+ dict_size = 1U << (zstd->windowlog + 10);
+
+ /* in case 2 z_erofs_load_zstd_config() race to avoid deadlock */
+ mutex_lock(&zstd_resize_mutex);
+ if (z_erofs_zstd_max_dictsize >= dict_size) {
+ mutex_unlock(&zstd_resize_mutex);
+ return 0;
+ }
+
+ /* 1. collect/isolate all streams for the following check */
+ while (z_erofs_zstd_avail_strms) {
+ struct z_erofs_zstd *n;
+
+ for (strm = z_erofs_isolate_strms(true); strm; strm = n) {
+ n = strm->next;
+ strm->next = head;
+ head = strm;
+ --z_erofs_zstd_avail_strms;
+ }
+ }
+
+ /* 2. walk each isolated stream and grow max dict_size if needed */
+ wkspsz = zstd_dstream_workspace_bound(dict_size);
+ for (strm = head; strm; strm = strm->next) {
+ wksp = kvmalloc(wkspsz, GFP_KERNEL);
+ if (!wksp)
+ break;
+ kvfree(strm->wksp);
+ strm->wksp = wksp;
+ strm->wkspsz = wkspsz;
+ }
+
+ /* 3. push back all to the global list and update max dict_size */
+ spin_lock(&z_erofs_zstd_lock);
+ DBG_BUGON(z_erofs_zstd_head);
+ z_erofs_zstd_head = head;
+ spin_unlock(&z_erofs_zstd_lock);
+ z_erofs_zstd_avail_strms = z_erofs_zstd_nstrms;
+ wake_up_all(&z_erofs_zstd_wq);
+ if (!strm)
+ z_erofs_zstd_max_dictsize = dict_size;
+ mutex_unlock(&zstd_resize_mutex);
+ return strm ? -ENOMEM : 0;
+}
+
+static const char *z_erofs_zstd_decompress(struct z_erofs_decompress_req *rq,
+ struct page **pgpl)
+{
+ struct super_block *sb = rq->sb;
+ struct z_erofs_stream_dctx dctx = { .rq = rq, .no = -1, .ni = 0 };
+ zstd_in_buffer in_buf = { NULL, 0, 0 };
+ zstd_out_buffer out_buf = { NULL, 0, 0 };
+ struct z_erofs_zstd *strm;
+ zstd_dstream *stream;
+ const char *reason;
+ int zerr;
+
+ /* 1. get the exact compressed size */
+ dctx.kin = kmap_local_page(*rq->in);
+ reason = z_erofs_fixup_insize(rq, dctx.kin + rq->pageofs_in,
+ min(rq->inputsize, sb->s_blocksize - rq->pageofs_in));
+ if (reason) {
+ kunmap_local(dctx.kin);
+ return reason;
+ }
+
+ /* 2. get an available ZSTD context */
+ strm = z_erofs_isolate_strms(false);
+
+ /* 3. multi-call decompress */
+ stream = zstd_init_dstream(z_erofs_zstd_max_dictsize, strm->wksp, strm->wkspsz);
+ if (!stream) {
+ reason = ERR_PTR(-ENOMEM);
+ goto failed_zinit;
+ }
+
+ rq->fillgaps = true; /* ZSTD doesn't support NULL output buffer */
+ in_buf.size = min_t(u32, rq->inputsize, PAGE_SIZE - rq->pageofs_in);
+ rq->inputsize -= in_buf.size;
+ in_buf.src = dctx.kin + rq->pageofs_in;
+ dctx.bounce = strm->bounce;
+
+ do {
+ dctx.inbuf_sz = in_buf.size;
+ dctx.inbuf_pos = in_buf.pos;
+ reason = z_erofs_stream_switch_bufs(&dctx, &out_buf.dst,
+ (void **)&in_buf.src, pgpl);
+ if (reason)
+ break;
+
+ if (out_buf.size == out_buf.pos) {
+ out_buf.size = dctx.avail_out;
+ out_buf.pos = 0;
+ }
+ in_buf.size = dctx.inbuf_sz;
+ in_buf.pos = dctx.inbuf_pos;
+
+ zerr = zstd_decompress_stream(stream, &out_buf, &in_buf);
+ dctx.avail_out = out_buf.size - out_buf.pos;
+ if (zstd_is_error(zerr) ||
+ ((rq->outputsize + dctx.avail_out) && (!zerr || (zerr > 0 &&
+ !(rq->inputsize + in_buf.size - in_buf.pos))))) {
+ reason = zstd_is_error(zerr) ? zstd_get_error_name(zerr) :
+ "unexpected end of stream";
+ break;
+ }
+ } while (rq->outputsize + dctx.avail_out);
+
+ if (dctx.kout)
+ kunmap_local(dctx.kout);
+failed_zinit:
+ kunmap_local(dctx.kin);
+ /* 4. push back ZSTD stream context to the global list */
+ spin_lock(&z_erofs_zstd_lock);
+ strm->next = z_erofs_zstd_head;
+ z_erofs_zstd_head = strm;
+ spin_unlock(&z_erofs_zstd_lock);
+ wake_up(&z_erofs_zstd_wq);
+ return reason;
+}
+
+const struct z_erofs_decompressor z_erofs_zstd_decomp = {
+ .config = z_erofs_load_zstd_config,
+ .decompress = z_erofs_zstd_decompress,
+ .init = z_erofs_zstd_init,
+ .exit = z_erofs_zstd_exit,
+ .name = "zstd",
+};
diff --git a/fs/erofs/dir.c b/fs/erofs/dir.c
new file mode 100644
index 000000000..4aa52a5f2
--- /dev/null
+++ b/fs/erofs/dir.c
@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ * https://www.huawei.com/
+ * Copyright (C) 2022, Alibaba Cloud
+ */
+#include "internal.h"
+#include <linux/filelock.h>
+
+static int erofs_fill_dentries(struct inode *dir, struct dir_context *ctx,
+ void *dentry_blk, struct erofs_dirent *de,
+ unsigned int nameoff0, unsigned int maxsize)
+{
+ const struct erofs_dirent *end = dentry_blk + nameoff0;
+
+ while (de < end) {
+ unsigned char d_type = fs_ftype_to_dtype(de->file_type);
+ unsigned int nameoff = le16_to_cpu(de->nameoff);
+ const char *de_name = (char *)dentry_blk + nameoff;
+ unsigned int de_namelen;
+
+ /* non-trailing dirent in the directory block? */
+ if (de + 1 < end)
+ de_namelen = le16_to_cpu(de[1].nameoff) - nameoff;
+ else if (maxsize <= nameoff)
+ goto err_bogus;
+ else
+ de_namelen = strnlen(de_name, maxsize - nameoff);
+
+ /* a corrupted entry is found (including negative namelen) */
+ if (!in_range32(de_namelen, 1, EROFS_NAME_LEN) ||
+ nameoff + de_namelen > maxsize)
+ goto err_bogus;
+
+ if (!dir_emit(ctx, de_name, de_namelen,
+ erofs_nid_to_ino64(EROFS_SB(dir->i_sb),
+ le64_to_cpu(de->nid)), d_type))
+ return 1;
+ ++de;
+ ctx->pos += sizeof(struct erofs_dirent);
+ }
+ return 0;
+err_bogus:
+ erofs_err(dir->i_sb, "bogus dirent @ nid %llu", EROFS_I(dir)->nid);
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+}
+
+static int erofs_readdir(struct file *f, struct dir_context *ctx)
+{
+ struct inode *dir = file_inode(f);
+ struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+ struct super_block *sb = dir->i_sb;
+ struct file_ra_state *ra = &f->f_ra;
+ unsigned long bsz = sb->s_blocksize;
+ unsigned int ofs = erofs_blkoff(sb, ctx->pos);
+ pgoff_t ra_pages = DIV_ROUND_UP_POW2(
+ EROFS_I_SB(dir)->dir_ra_bytes, PAGE_SIZE);
+ pgoff_t nr_pages = DIV_ROUND_UP_POW2(dir->i_size, PAGE_SIZE);
+ int err = 0;
+ bool initial = true;
+
+ buf.mapping = dir->i_mapping;
+ while (ctx->pos < dir->i_size) {
+ erofs_off_t dbstart = ctx->pos - ofs;
+ struct erofs_dirent *de;
+ unsigned int nameoff, maxsize;
+
+ if (fatal_signal_pending(current)) {
+ err = -ERESTARTSYS;
+ break;
+ }
+
+ /* readahead blocks to enhance performance for large directories */
+ if (ra_pages) {
+ pgoff_t idx = DIV_ROUND_UP_POW2(ctx->pos, PAGE_SIZE);
+ pgoff_t pages = min(nr_pages - idx, ra_pages);
+
+ if (pages > 1 && !ra_has_index(ra, idx))
+ page_cache_sync_readahead(dir->i_mapping, ra,
+ f, idx, pages);
+ }
+
+ de = erofs_bread(&buf, dbstart, true);
+ if (IS_ERR(de)) {
+ erofs_err(sb, "failed to readdir of logical block %llu of nid %llu",
+ erofs_blknr(sb, dbstart), EROFS_I(dir)->nid);
+ err = PTR_ERR(de);
+ break;
+ }
+
+ nameoff = le16_to_cpu(de->nameoff);
+ if (!nameoff || nameoff >= bsz || (nameoff % sizeof(*de))) {
+ erofs_err(sb, "invalid de[0].nameoff %u @ nid %llu",
+ nameoff, EROFS_I(dir)->nid);
+ err = -EFSCORRUPTED;
+ break;
+ }
+
+ maxsize = min_t(unsigned int, dir->i_size - dbstart, bsz);
+ /* search dirents at the arbitrary position */
+ if (initial) {
+ initial = false;
+ ofs = roundup(ofs, sizeof(struct erofs_dirent));
+ ctx->pos = dbstart + ofs;
+ }
+
+ err = erofs_fill_dentries(dir, ctx, de, (void *)de + ofs,
+ nameoff, maxsize);
+ if (err)
+ break;
+ ctx->pos = dbstart + maxsize;
+ ofs = 0;
+ cond_resched();
+ }
+ erofs_put_metabuf(&buf);
+ if (EROFS_I(dir)->dot_omitted && ctx->pos == dir->i_size) {
+ if (!dir_emit_dot(f, ctx))
+ return 0;
+ ++ctx->pos;
+ }
+ return err < 0 ? err : 0;
+}
+
+const struct file_operations erofs_dir_fops = {
+ .llseek = generic_file_llseek,
+ .read = generic_read_dir,
+ .iterate_shared = erofs_readdir,
+ .unlocked_ioctl = erofs_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = erofs_compat_ioctl,
+#endif
+ .setlease = generic_setlease,
+};
diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
new file mode 100644
index 000000000..16ec4fd33
--- /dev/null
+++ b/fs/erofs/erofs_fs.h
@@ -0,0 +1,469 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * EROFS (Enhanced ROM File System) on-disk format definition
+ *
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ * https://www.huawei.com/
+ * Copyright (C) 2021, Alibaba Cloud
+ */
+#ifndef __EROFS_FS_H
+#define __EROFS_FS_H
+
+/* to allow for x86 boot sectors and other oddities. */
+#define EROFS_SUPER_OFFSET 1024
+
+#define EROFS_FEATURE_COMPAT_SB_CHKSUM 0x00000001
+#define EROFS_FEATURE_COMPAT_MTIME 0x00000002
+#define EROFS_FEATURE_COMPAT_XATTR_FILTER 0x00000004
+#define EROFS_FEATURE_COMPAT_SHARED_EA_IN_METABOX 0x00000008
+#define EROFS_FEATURE_COMPAT_PLAIN_XATTR_PFX 0x00000010
+#define EROFS_FEATURE_COMPAT_ISHARE_XATTRS 0x00000020
+
+/*
+ * Any bits that aren't in EROFS_ALL_FEATURE_INCOMPAT should
+ * be incompatible with this kernel version.
+ */
+#define EROFS_FEATURE_INCOMPAT_LZ4_0PADDING 0x00000001
+#define EROFS_FEATURE_INCOMPAT_COMPR_CFGS 0x00000002
+#define EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER 0x00000002
+#define EROFS_FEATURE_INCOMPAT_CHUNKED_FILE 0x00000004
+#define EROFS_FEATURE_INCOMPAT_DEVICE_TABLE 0x00000008
+#define EROFS_FEATURE_INCOMPAT_COMPR_HEAD2 0x00000008
+#define EROFS_FEATURE_INCOMPAT_ZTAILPACKING 0x00000010
+#define EROFS_FEATURE_INCOMPAT_FRAGMENTS 0x00000020
+#define EROFS_FEATURE_INCOMPAT_DEDUPE 0x00000020
+#define EROFS_FEATURE_INCOMPAT_XATTR_PREFIXES 0x00000040
+#define EROFS_FEATURE_INCOMPAT_48BIT 0x00000080
+#define EROFS_FEATURE_INCOMPAT_METABOX 0x00000100
+#define EROFS_ALL_FEATURE_INCOMPAT \
+ ((EROFS_FEATURE_INCOMPAT_METABOX << 1) - 1)
+
+#define EROFS_SB_EXTSLOT_SIZE 16
+
+struct erofs_deviceslot {
+ u8 tag[64]; /* digest(sha256), etc. */
+ __le32 blocks_lo; /* total blocks count of this device */
+ __le32 uniaddr_lo; /* unified starting block of this device */
+ __le16 blocks_hi; /* total blocks count MSB */
+ __le16 uniaddr_hi; /* unified starting block MSB */
+ u8 reserved[52];
+};
+#define EROFS_DEVT_SLOT_SIZE sizeof(struct erofs_deviceslot)
+
+/* erofs on-disk super block (currently 144 bytes at maximum) */
+struct erofs_super_block {
+ __le32 magic; /* file system magic number */
+ __le32 checksum; /* crc32c to avoid unexpected on-disk overlap */
+ __le32 feature_compat;
+ __u8 blkszbits; /* filesystem block size in bit shift */
+ __u8 sb_extslots; /* superblock size = 128 + sb_extslots * 16 */
+ union {
+ __le16 rootnid_2b; /* nid of root directory */
+ __le16 blocks_hi; /* (48BIT on) blocks count MSB */
+ } __packed rb;
+ __le64 inos; /* total valid ino # (== f_files - f_favail) */
+ __le64 epoch; /* base seconds used for compact inodes */
+ __le32 fixed_nsec; /* fixed nanoseconds for compact inodes */
+ __le32 blocks_lo; /* blocks count LSB */
+ __le32 meta_blkaddr; /* start block address of metadata area */
+ __le32 xattr_blkaddr; /* start block address of shared xattr area */
+ __u8 uuid[16]; /* 128-bit uuid for volume */
+ __u8 volume_name[16]; /* volume name */
+ __le32 feature_incompat;
+ union {
+ /* bitmap for available compression algorithms */
+ __le16 available_compr_algs;
+ /* customized sliding window size instead of 64k by default */
+ __le16 lz4_max_distance;
+ } __packed u1;
+ __le16 extra_devices; /* # of devices besides the primary device */
+ __le16 devt_slotoff; /* startoff = devt_slotoff * devt_slotsize */
+ __u8 dirblkbits; /* directory block size in bit shift */
+ __u8 xattr_prefix_count; /* # of long xattr name prefixes */
+ __le32 xattr_prefix_start; /* start of long xattr prefixes */
+ __le64 packed_nid; /* nid of the special packed inode */
+ __u8 xattr_filter_reserved; /* reserved for xattr name filter */
+ __u8 ishare_xattr_prefix_id;
+ __u8 reserved[2];
+ __le32 build_time; /* seconds added to epoch for mkfs time */
+ __le64 rootnid_8b; /* (48BIT on) nid of root directory */
+ __le64 reserved2;
+ __le64 metabox_nid; /* (METABOX on) nid of the metabox inode */
+ __le64 reserved3; /* [align to extslot 1] */
+};
+
+/*
+ * EROFS inode datalayout (i_format in on-disk inode):
+ * 0 - uncompressed flat inode without tail-packing inline data:
+ * 1 - compressed inode with non-compact indexes:
+ * 2 - uncompressed flat inode with tail-packing inline data:
+ * 3 - compressed inode with compact indexes:
+ * 4 - chunk-based inode with (optional) multi-device support:
+ * 5~7 - reserved
+ */
+enum {
+ EROFS_INODE_FLAT_PLAIN = 0,
+ EROFS_INODE_COMPRESSED_FULL = 1,
+ EROFS_INODE_FLAT_INLINE = 2,
+ EROFS_INODE_COMPRESSED_COMPACT = 3,
+ EROFS_INODE_CHUNK_BASED = 4,
+ EROFS_INODE_DATALAYOUT_MAX
+};
+
+static inline bool erofs_inode_is_data_compressed(unsigned int datamode)
+{
+ return datamode == EROFS_INODE_COMPRESSED_COMPACT ||
+ datamode == EROFS_INODE_COMPRESSED_FULL;
+}
+
+/* bit definitions of inode i_format */
+#define EROFS_I_VERSION_MASK 0x01
+#define EROFS_I_DATALAYOUT_MASK 0x07
+
+#define EROFS_I_VERSION_BIT 0
+#define EROFS_I_DATALAYOUT_BIT 1
+#define EROFS_I_NLINK_1_BIT 4 /* non-directory compact inodes only */
+#define EROFS_I_DOT_OMITTED_BIT 4 /* (directories) omit the `.` dirent */
+#define EROFS_I_ALL ((1 << (EROFS_I_NLINK_1_BIT + 1)) - 1)
+
+/* indicate chunk blkbits, thus 'chunksize = blocksize << chunk blkbits' */
+#define EROFS_CHUNK_FORMAT_BLKBITS_MASK 0x001F
+/* with chunk indexes or just a 4-byte block array */
+#define EROFS_CHUNK_FORMAT_INDEXES 0x0020
+#define EROFS_CHUNK_FORMAT_48BIT 0x0040
+
+#define EROFS_CHUNK_FORMAT_ALL ((EROFS_CHUNK_FORMAT_48BIT << 1) - 1)
+
+/* 32-byte on-disk inode */
+#define EROFS_INODE_LAYOUT_COMPACT 0
+/* 64-byte on-disk inode */
+#define EROFS_INODE_LAYOUT_EXTENDED 1
+
+struct erofs_inode_chunk_info {
+ __le16 format; /* chunk blkbits, etc. */
+ __le16 reserved;
+};
+
+union erofs_inode_i_u {
+ __le32 blocks_lo; /* total blocks count (if compressed inodes) */
+ __le32 startblk_lo; /* starting block number (if flat inodes) */
+ __le32 rdev; /* device ID (if special inodes) */
+ struct erofs_inode_chunk_info c;
+};
+
+union erofs_inode_i_nb {
+ __le16 nlink; /* if EROFS_I_NLINK_1_BIT is unset */
+ __le16 blocks_hi; /* total blocks count MSB */
+ __le16 startblk_hi; /* starting block number MSB */
+} __packed;
+
+/* 32-byte reduced form of an ondisk inode */
+struct erofs_inode_compact {
+ __le16 i_format; /* inode format hints */
+ __le16 i_xattr_icount;
+ __le16 i_mode;
+ union erofs_inode_i_nb i_nb;
+ __le32 i_size;
+ __le32 i_mtime;
+ union erofs_inode_i_u i_u;
+
+ __le32 i_ino; /* only used for 32-bit stat compatibility */
+ __le16 i_uid;
+ __le16 i_gid;
+ __le32 i_reserved;
+};
+
+/* 64-byte complete form of an ondisk inode */
+struct erofs_inode_extended {
+ __le16 i_format; /* inode format hints */
+ __le16 i_xattr_icount;
+ __le16 i_mode;
+ union erofs_inode_i_nb i_nb;
+ __le64 i_size;
+ union erofs_inode_i_u i_u;
+
+ __le32 i_ino; /* only used for 32-bit stat compatibility */
+ __le32 i_uid;
+ __le32 i_gid;
+ __le64 i_mtime;
+ __le32 i_mtime_nsec;
+ __le32 i_nlink;
+ __u8 i_reserved2[16];
+};
+
+/*
+ * inline xattrs (n == i_xattr_icount):
+ * erofs_xattr_ibody_header(1) + (n - 1) * 4 bytes
+ * 12 bytes / \
+ * / \
+ * /-----------------------\
+ * | erofs_xattr_entries+ |
+ * +-----------------------+
+ * inline xattrs must starts in erofs_xattr_ibody_header,
+ * for read-only fs, no need to introduce h_refcount
+ */
+struct erofs_xattr_ibody_header {
+ __le32 h_name_filter; /* bit value 1 indicates not-present */
+ __u8 h_shared_count;
+ __u8 h_reserved2[7];
+ __le32 h_shared_xattrs[]; /* shared xattr id array */
+};
+
+/* Name indexes */
+#define EROFS_XATTR_INDEX_USER 1
+#define EROFS_XATTR_INDEX_POSIX_ACL_ACCESS 2
+#define EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT 3
+#define EROFS_XATTR_INDEX_TRUSTED 4
+#define EROFS_XATTR_INDEX_LUSTRE 5
+#define EROFS_XATTR_INDEX_SECURITY 6
+
+/*
+ * bit 7 of e_name_index is set when it refers to a long xattr name prefix,
+ * while the remained lower bits represent the index of the prefix.
+ */
+#define EROFS_XATTR_LONG_PREFIX 0x80
+#define EROFS_XATTR_LONG_PREFIX_MASK 0x7f
+
+#define EROFS_XATTR_FILTER_BITS 32
+#define EROFS_XATTR_FILTER_DEFAULT UINT32_MAX
+#define EROFS_XATTR_FILTER_SEED 0x25BBE08F
+
+/* xattr entry (for both inline & shared xattrs) */
+struct erofs_xattr_entry {
+ __u8 e_name_len; /* length of name */
+ __u8 e_name_index; /* attribute name index */
+ __le16 e_value_size; /* size of attribute value */
+ /* followed by e_name and e_value */
+ char e_name[]; /* attribute name */
+};
+
+/* long xattr name prefix */
+struct erofs_xattr_long_prefix {
+ __u8 base_index; /* short xattr name prefix index */
+ char infix[]; /* infix apart from short prefix */
+};
+
+static inline unsigned int erofs_xattr_ibody_size(__le16 i_xattr_icount)
+{
+ if (!i_xattr_icount)
+ return 0;
+
+ /* 1 header + n-1 * 4 bytes inline xattr to keep continuity */
+ return sizeof(struct erofs_xattr_ibody_header) +
+ sizeof(__u32) * (le16_to_cpu(i_xattr_icount) - 1);
+}
+
+#define EROFS_XATTR_ALIGN(size) round_up(size, sizeof(struct erofs_xattr_entry))
+
+static inline unsigned int erofs_xattr_entry_size(struct erofs_xattr_entry *e)
+{
+ return EROFS_XATTR_ALIGN(sizeof(struct erofs_xattr_entry) +
+ e->e_name_len + le16_to_cpu(e->e_value_size));
+}
+
+/* represent a zeroed chunk (hole) */
+#define EROFS_NULL_ADDR -1
+
+/* 4-byte block address array */
+#define EROFS_BLOCK_MAP_ENTRY_SIZE sizeof(__le32)
+
+/* 8-byte inode chunk index */
+struct erofs_inode_chunk_index {
+ __le16 startblk_hi; /* starting block number MSB */
+ __le16 device_id; /* back-end storage id (with bits masked) */
+ __le32 startblk_lo; /* starting block number of this chunk */
+};
+
+#define EROFS_DIRENT_NID_METABOX_BIT 63
+#define EROFS_DIRENT_NID_MASK (BIT_ULL(EROFS_DIRENT_NID_METABOX_BIT) - 1)
+
+/* dirent sorts in alphabet order, thus we can do binary search */
+struct erofs_dirent {
+ __le64 nid; /* node number */
+ __le16 nameoff; /* start offset of file name */
+ __u8 file_type; /* file type */
+ __u8 reserved; /* reserved */
+} __packed;
+
+/*
+ * EROFS file types should match generic FT_* types and
+ * it seems no need to add BUILD_BUG_ONs since potential
+ * unmatchness will break other fses as well...
+ */
+
+#define EROFS_NAME_LEN 255
+
+/* maximum supported encoded size of a physical compressed cluster */
+#define Z_EROFS_PCLUSTER_MAX_SIZE (1024 * 1024)
+
+/* maximum supported decoded size of a physical compressed cluster */
+#define Z_EROFS_PCLUSTER_MAX_DSIZE (12 * 1024 * 1024)
+
+/* available compression algorithm types (for h_algorithmtype) */
+enum {
+ Z_EROFS_COMPRESSION_LZ4 = 0,
+ Z_EROFS_COMPRESSION_LZMA = 1,
+ Z_EROFS_COMPRESSION_DEFLATE = 2,
+ Z_EROFS_COMPRESSION_ZSTD = 3,
+ Z_EROFS_COMPRESSION_MAX
+};
+#define Z_EROFS_ALL_COMPR_ALGS ((1 << Z_EROFS_COMPRESSION_MAX) - 1)
+
+/* 14 bytes (+ length field = 16 bytes) */
+struct z_erofs_lz4_cfgs {
+ __le16 max_distance;
+ __le16 max_pclusterblks;
+ u8 reserved[10];
+} __packed;
+
+/* 14 bytes (+ length field = 16 bytes) */
+struct z_erofs_lzma_cfgs {
+ __le32 dict_size;
+ __le16 format;
+ u8 reserved[8];
+} __packed;
+
+#define Z_EROFS_LZMA_MAX_DICT_SIZE (8 * Z_EROFS_PCLUSTER_MAX_SIZE)
+
+/* 6 bytes (+ length field = 8 bytes) */
+struct z_erofs_deflate_cfgs {
+ u8 windowbits; /* 8..15 for DEFLATE */
+ u8 reserved[5];
+} __packed;
+
+/* 6 bytes (+ length field = 8 bytes) */
+struct z_erofs_zstd_cfgs {
+ u8 format;
+ u8 windowlog; /* windowLog - ZSTD_WINDOWLOG_ABSOLUTEMIN(10) */
+ u8 reserved[4];
+} __packed;
+
+#define Z_EROFS_ZSTD_MAX_DICT_SIZE Z_EROFS_PCLUSTER_MAX_SIZE
+
+/*
+ * Enable COMPACTED_2B for EROFS_INODE_COMPRESSED_COMPACT inodes:
+ * 4B (disabled) vs 4B+2B+4B (enabled)
+ */
+#define Z_EROFS_ADVISE_COMPACTED_2B 0x0001
+/* Enable extent metadata for EROFS_INODE_COMPRESSED_FULL inodes */
+#define Z_EROFS_ADVISE_EXTENTS 0x0001
+#define Z_EROFS_ADVISE_BIG_PCLUSTER_1 0x0002
+#define Z_EROFS_ADVISE_BIG_PCLUSTER_2 0x0004
+#define Z_EROFS_ADVISE_INLINE_PCLUSTER 0x0008
+#define Z_EROFS_ADVISE_INTERLACED_PCLUSTER 0x0010
+#define Z_EROFS_ADVISE_FRAGMENT_PCLUSTER 0x0020
+/* Indicate the record size for each extent if extent metadata is used */
+#define Z_EROFS_ADVISE_EXTRECSZ_BIT 1
+#define Z_EROFS_ADVISE_EXTRECSZ_MASK 0x3
+
+#define Z_EROFS_FRAGMENT_INODE_BIT 7
+struct z_erofs_map_header {
+ union {
+ /* fragment data offset in the packed inode */
+ __le32 h_fragmentoff;
+ struct {
+ __le16 h_reserved1;
+ /* indicates the encoded size of tailpacking data */
+ __le16 h_idata_size;
+ };
+ __le32 h_extents_lo; /* extent count LSB */
+ };
+ __le16 h_advise;
+ union {
+ struct {
+ /* algorithm type (bit 0-3: HEAD1; bit 4-7: HEAD2) */
+ __u8 h_algorithmtype;
+ /*
+ * bit 0-3 : logical cluster bits - blkszbits
+ * bit 4-6 : reserved
+ * bit 7 : pack the whole file into packed inode
+ */
+ __u8 h_clusterbits;
+ } __packed;
+ __le16 h_extents_hi; /* extent count MSB */
+ } __packed;
+};
+
+enum {
+ Z_EROFS_LCLUSTER_TYPE_PLAIN = 0,
+ Z_EROFS_LCLUSTER_TYPE_HEAD1 = 1,
+ Z_EROFS_LCLUSTER_TYPE_NONHEAD = 2,
+ Z_EROFS_LCLUSTER_TYPE_HEAD2 = 3,
+ Z_EROFS_LCLUSTER_TYPE_MAX
+};
+
+#define Z_EROFS_LI_LCLUSTER_TYPE_MASK (Z_EROFS_LCLUSTER_TYPE_MAX - 1)
+
+/* (noncompact only, HEAD) This pcluster refers to partial decompressed data */
+#define Z_EROFS_LI_PARTIAL_REF (1 << 15)
+/* (noncompact only, HEAD) This pcluster can also be regarded as a HOLE */
+#define Z_EROFS_LI_HOLE (1 << 14)
+
+/* Set on 1st non-head lcluster to store compressed block counti (in blocks) */
+#define Z_EROFS_LI_D0_CBLKCNT (1 << 11)
+
+struct z_erofs_lcluster_index {
+ __le16 di_advise;
+ /* where to decompress in the head lcluster */
+ __le16 di_clusterofs;
+
+ union {
+ __le32 blkaddr; /* for the HEAD lclusters */
+ /*
+ * [0] - distance to its HEAD lcluster
+ * [1] - distance to the next HEAD lcluster
+ */
+ __le16 delta[2]; /* for the NONHEAD lclusters */
+ } di_u;
+};
+
+#define Z_EROFS_MAP_HEADER_END(end) \
+ (ALIGN(end, 8) + sizeof(struct z_erofs_map_header))
+#define Z_EROFS_FULL_INDEX_START(end) (Z_EROFS_MAP_HEADER_END(end) + 8)
+
+#define Z_EROFS_EXTENT_PLEN_PARTIAL BIT(27)
+#define Z_EROFS_EXTENT_PLEN_FMT_BIT 28
+#define Z_EROFS_EXTENT_PLEN_MASK ((Z_EROFS_PCLUSTER_MAX_SIZE << 1) - 1)
+struct z_erofs_extent {
+ __le32 plen; /* encoded length */
+ __le32 pstart_lo; /* physical offset */
+ __le32 pstart_hi; /* physical offset MSB */
+ __le32 lstart_lo; /* logical offset */
+ __le32 lstart_hi; /* logical offset MSB (>= 4GiB inodes) */
+ __u8 reserved[12]; /* for future use */
+};
+
+static inline int z_erofs_extent_recsize(unsigned int advise)
+{
+ return 4 << ((advise >> Z_EROFS_ADVISE_EXTRECSZ_BIT) &
+ Z_EROFS_ADVISE_EXTRECSZ_MASK);
+}
+
+/* check the EROFS on-disk layout strictly at compile time */
+static inline void erofs_check_ondisk_layout_definitions(void)
+{
+ const __le64 fmh = *(__le64 *)&(struct z_erofs_map_header) {
+ .h_clusterbits = 1 << Z_EROFS_FRAGMENT_INODE_BIT
+ };
+
+ BUILD_BUG_ON(sizeof(struct erofs_super_block) != 144);
+ BUILD_BUG_ON(sizeof(struct erofs_inode_compact) != 32);
+ BUILD_BUG_ON(sizeof(struct erofs_inode_extended) != 64);
+ BUILD_BUG_ON(sizeof(struct erofs_xattr_ibody_header) != 12);
+ BUILD_BUG_ON(sizeof(struct erofs_xattr_entry) != 4);
+ BUILD_BUG_ON(sizeof(struct erofs_inode_chunk_info) != 4);
+ BUILD_BUG_ON(sizeof(struct erofs_inode_chunk_index) != 8);
+ BUILD_BUG_ON(sizeof(struct z_erofs_map_header) != 8);
+ BUILD_BUG_ON(sizeof(struct z_erofs_lcluster_index) != 8);
+ BUILD_BUG_ON(sizeof(struct erofs_dirent) != 12);
+ /* keep in sync between 2 index structures for better extendibility */
+ BUILD_BUG_ON(sizeof(struct erofs_inode_chunk_index) !=
+ sizeof(struct z_erofs_lcluster_index));
+ BUILD_BUG_ON(sizeof(struct erofs_deviceslot) != 128);
+
+ /* exclude old compiler versions like gcc 7.5.0 */
+ BUILD_BUG_ON(__builtin_constant_p(fmh) ?
+ fmh != cpu_to_le64(1ULL << 63) : 0);
+}
+
+#endif
diff --git a/fs/erofs/fileio.c b/fs/erofs/fileio.c
new file mode 100644
index 000000000..ebb81a7ff
--- /dev/null
+++ b/fs/erofs/fileio.c
@@ -0,0 +1,217 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2024, Alibaba Cloud
+ */
+#include "internal.h"
+#include <trace/events/erofs.h>
+
+struct erofs_fileio_rq {
+ struct bio_vec bvecs[16];
+ struct bio bio;
+ struct kiocb iocb;
+ struct super_block *sb;
+ refcount_t ref;
+};
+
+struct erofs_fileio {
+ struct erofs_map_blocks map;
+ struct erofs_map_dev dev;
+ struct erofs_fileio_rq *rq;
+};
+
+static void erofs_fileio_ki_complete(struct kiocb *iocb, long ret)
+{
+ struct erofs_fileio_rq *rq =
+ container_of(iocb, struct erofs_fileio_rq, iocb);
+ struct folio_iter fi;
+
+ if (ret >= 0 && ret != rq->bio.bi_iter.bi_size)
+ ret = -EIO;
+ if (!rq->bio.bi_end_io) {
+ bio_for_each_folio_all(fi, &rq->bio) {
+ DBG_BUGON(folio_test_uptodate(fi.folio));
+ erofs_onlinefolio_end(fi.folio, ret < 0, false);
+ }
+ } else if (ret < 0 && !rq->bio.bi_status) {
+ rq->bio.bi_status = errno_to_blk_status(ret);
+ }
+ bio_endio(&rq->bio);
+ bio_uninit(&rq->bio);
+ if (refcount_dec_and_test(&rq->ref))
+ kfree(rq);
+}
+
+static void erofs_fileio_rq_submit(struct erofs_fileio_rq *rq)
+{
+ struct iov_iter iter;
+ ssize_t ret;
+
+ if (!rq)
+ return;
+ rq->iocb.ki_pos = rq->bio.bi_iter.bi_sector << SECTOR_SHIFT;
+ rq->iocb.ki_ioprio = get_current_ioprio();
+ rq->iocb.ki_complete = erofs_fileio_ki_complete;
+ if (test_opt(&EROFS_SB(rq->sb)->opt, DIRECT_IO) &&
+ rq->iocb.ki_filp->f_mode & FMODE_CAN_ODIRECT)
+ rq->iocb.ki_flags = IOCB_DIRECT;
+ iov_iter_bvec(&iter, ITER_DEST, rq->bvecs, rq->bio.bi_vcnt,
+ rq->bio.bi_iter.bi_size);
+ scoped_with_creds(rq->iocb.ki_filp->f_cred)
+ ret = vfs_iocb_iter_read(rq->iocb.ki_filp, &rq->iocb, &iter);
+ if (ret != -EIOCBQUEUED)
+ erofs_fileio_ki_complete(&rq->iocb, ret);
+ if (refcount_dec_and_test(&rq->ref))
+ kfree(rq);
+}
+
+static struct erofs_fileio_rq *erofs_fileio_rq_alloc(struct erofs_map_dev *mdev)
+{
+ struct erofs_fileio_rq *rq = kzalloc_obj(*rq, GFP_KERNEL | __GFP_NOFAIL);
+
+ bio_init(&rq->bio, NULL, rq->bvecs, ARRAY_SIZE(rq->bvecs), REQ_OP_READ);
+ rq->iocb.ki_filp = mdev->m_dif->file;
+ rq->sb = mdev->m_sb;
+ refcount_set(&rq->ref, 2);
+ return rq;
+}
+
+struct bio *erofs_fileio_bio_alloc(struct erofs_map_dev *mdev)
+{
+ return &erofs_fileio_rq_alloc(mdev)->bio;
+}
+
+void erofs_fileio_submit_bio(struct bio *bio)
+{
+ return erofs_fileio_rq_submit(container_of(bio, struct erofs_fileio_rq,
+ bio));
+}
+
+static int erofs_fileio_scan_folio(struct erofs_fileio *io,
+ struct inode *inode, struct folio *folio)
+{
+ struct erofs_map_blocks *map = &io->map;
+ unsigned int cur = 0, end = folio_size(folio), len, attached = 0;
+ loff_t pos = folio_pos(folio), ofs;
+ int err = 0;
+
+ erofs_onlinefolio_init(folio);
+ while (cur < end) {
+ if (!in_range(pos + cur, map->m_la, map->m_llen)) {
+ map->m_la = pos + cur;
+ map->m_llen = end - cur;
+ err = erofs_map_blocks(inode, map);
+ if (err)
+ break;
+ }
+
+ ofs = folio_pos(folio) + cur - map->m_la;
+ len = min_t(loff_t, map->m_llen - ofs, end - cur);
+ if (map->m_flags & EROFS_MAP_META) {
+ struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+ void *src;
+
+ src = erofs_read_metabuf(&buf, inode->i_sb,
+ map->m_pa + ofs, erofs_inode_in_metabox(inode));
+ if (IS_ERR(src)) {
+ err = PTR_ERR(src);
+ break;
+ }
+ memcpy_to_folio(folio, cur, src, len);
+ erofs_put_metabuf(&buf);
+ } else if (!(map->m_flags & EROFS_MAP_MAPPED)) {
+ folio_zero_segment(folio, cur, cur + len);
+ attached = 0;
+ } else {
+ if (io->rq && (map->m_pa + ofs != io->dev.m_pa ||
+ map->m_deviceid != io->dev.m_deviceid)) {
+io_retry:
+ erofs_fileio_rq_submit(io->rq);
+ io->rq = NULL;
+ }
+
+ if (!io->rq) {
+ io->dev = (struct erofs_map_dev) {
+ .m_pa = io->map.m_pa + ofs,
+ .m_deviceid = io->map.m_deviceid,
+ };
+ err = erofs_map_dev(inode->i_sb, &io->dev);
+ if (err)
+ break;
+ io->rq = erofs_fileio_rq_alloc(&io->dev);
+ io->rq->bio.bi_iter.bi_sector =
+ (io->dev.m_dif->fsoff + io->dev.m_pa) >> 9;
+ attached = 0;
+ }
+ if (!bio_add_folio(&io->rq->bio, folio, len, cur))
+ goto io_retry;
+ if (!attached++)
+ erofs_onlinefolio_split(folio);
+ io->dev.m_pa += len;
+ }
+ cur += len;
+ }
+ erofs_onlinefolio_end(folio, err, false);
+ return err;
+}
+
+static int erofs_fileio_read_folio(struct file *file, struct folio *folio)
+{
+ bool need_iput;
+ struct inode *realinode = erofs_real_inode(folio_inode(folio), &need_iput);
+ struct erofs_fileio io = {};
+ int err;
+
+ trace_erofs_read_folio(realinode, folio, true);
+ err = erofs_fileio_scan_folio(&io, realinode, folio);
+ erofs_fileio_rq_submit(io.rq);
+ if (need_iput)
+ iput(realinode);
+ return err;
+}
+
+static void erofs_fileio_readahead(struct readahead_control *rac)
+{
+ bool need_iput;
+ struct inode *realinode = erofs_real_inode(rac->mapping->host, &need_iput);
+ struct erofs_fileio io = {};
+ struct folio *folio;
+ int err;
+
+ trace_erofs_readahead(realinode, readahead_index(rac),
+ readahead_count(rac), true);
+ while ((folio = readahead_folio(rac))) {
+ err = erofs_fileio_scan_folio(&io, realinode, folio);
+ if (err && err != -EINTR)
+ erofs_err(realinode->i_sb, "readahead error at folio %lu @ nid %llu",
+ folio->index, EROFS_I(realinode)->nid);
+ }
+ erofs_fileio_rq_submit(io.rq);
+ if (need_iput)
+ iput(realinode);
+}
+
+const struct address_space_operations erofs_fileio_aops = {
+ .read_folio = erofs_fileio_read_folio,
+ .readahead = erofs_fileio_readahead,
+};
+
+int erofs_read_meta_folio(struct file *file, struct folio *folio)
+{
+ struct erofs_fileio io = {
+ .dev = { .m_pa = folio_pos(folio), },
+ };
+ struct inode *inode = folio_inode(folio);
+ int err;
+
+ err = erofs_map_dev(inode->i_sb, &io.dev);
+ if (err)
+ return err;
+
+ io.rq = erofs_fileio_rq_alloc(&io.dev);
+ io.rq->bio.bi_iter.bi_sector =
+ (io.dev.m_dif->fsoff + io.dev.m_pa) >> 9;
+ erofs_onlinefolio_init(folio);
+ bio_add_folio_nofail(&io.rq->bio, folio, folio_size(folio), 0);
+ erofs_fileio_rq_submit(io.rq);
+ return 0;
+}
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
new file mode 100644
index 000000000..45afe5c50
--- /dev/null
+++ b/fs/erofs/inode.c
@@ -0,0 +1,399 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ * https://www.huawei.com/
+ * Copyright (C) 2021, Alibaba Cloud
+ */
+#include "xattr.h"
+#include <linux/compat.h>
+#include <trace/events/erofs.h>
+
+static int erofs_fill_symlink(struct inode *inode, void *bptr, unsigned int ofs)
+{
+ struct erofs_inode *vi = EROFS_I(inode);
+ char *link;
+ loff_t end;
+
+ ofs += vi->xattr_isize;
+ /* check whether the symlink data is small enough to be inlined */
+ if (vi->datalayout == EROFS_INODE_FLAT_INLINE &&
+ !check_add_overflow(ofs, inode->i_size, &end) &&
+ end <= i_blocksize(inode)) {
+ link = kmemdup_nul(bptr + ofs, inode->i_size, GFP_KERNEL);
+ if (!link)
+ return -ENOMEM;
+ if (unlikely(!inode->i_size || strlen(link) != inode->i_size)) {
+ erofs_err(inode->i_sb, "invalid fast symlink size %llu @ nid %llu",
+ inode->i_size | 0ULL, vi->nid);
+ kfree(link);
+ return -EFSCORRUPTED;
+ }
+ inode_set_cached_link(inode, link, inode->i_size);
+ }
+ return 0;
+}
+
+static int erofs_read_inode(struct inode *inode)
+{
+ struct super_block *sb = inode->i_sb;
+ erofs_blk_t blkaddr = erofs_blknr(sb, erofs_iloc(inode));
+ unsigned int ofs = erofs_blkoff(sb, erofs_iloc(inode));
+ bool in_mbox = erofs_inode_in_metabox(inode);
+ struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ erofs_blk_t addrmask = BIT_ULL(48) - 1;
+ struct erofs_inode *vi = EROFS_I(inode);
+ struct erofs_inode_extended *die, copied;
+ struct erofs_inode_compact *dic;
+ unsigned int ifmt;
+ void *ptr;
+ int err = 0;
+
+ ptr = erofs_read_metabuf(&buf, sb, erofs_pos(sb, blkaddr), in_mbox);
+ if (IS_ERR(ptr)) {
+ err = PTR_ERR(ptr);
+ erofs_err(sb, "failed to read inode meta block (nid: %llu): %d",
+ vi->nid, err);
+ goto err_out;
+ }
+
+ dic = ptr + ofs;
+ ifmt = le16_to_cpu(dic->i_format);
+ if (ifmt & ~EROFS_I_ALL) {
+ erofs_err(sb, "unsupported i_format %u of nid %llu",
+ ifmt, vi->nid);
+ err = -EOPNOTSUPP;
+ goto err_out;
+ }
+
+ vi->datalayout = erofs_inode_datalayout(ifmt);
+ if (vi->datalayout >= EROFS_INODE_DATALAYOUT_MAX) {
+ erofs_err(sb, "unsupported datalayout %u of nid %llu",
+ vi->datalayout, vi->nid);
+ err = -EOPNOTSUPP;
+ goto err_out;
+ }
+
+ switch (erofs_inode_version(ifmt)) {
+ case EROFS_INODE_LAYOUT_EXTENDED:
+ vi->inode_isize = sizeof(struct erofs_inode_extended);
+ /* check if the extended inode acrosses block boundary */
+ if (ofs + vi->inode_isize <= sb->s_blocksize) {
+ ofs += vi->inode_isize;
+ die = (struct erofs_inode_extended *)dic;
+ copied.i_u = die->i_u;
+ copied.i_nb = die->i_nb;
+ } else {
+ const unsigned int gotten = sb->s_blocksize - ofs;
+
+ memcpy(&copied, dic, gotten);
+ ptr = erofs_read_metabuf(&buf, sb,
+ erofs_pos(sb, blkaddr + 1), in_mbox);
+ if (IS_ERR(ptr)) {
+ err = PTR_ERR(ptr);
+ erofs_err(sb, "failed to read inode payload block (nid: %llu): %d",
+ vi->nid, err);
+ goto err_out;
+ }
+ ofs = vi->inode_isize - gotten;
+ memcpy((u8 *)&copied + gotten, ptr, ofs);
+ die = &copied;
+ }
+ vi->xattr_isize = erofs_xattr_ibody_size(die->i_xattr_icount);
+
+ inode->i_mode = le16_to_cpu(die->i_mode);
+ i_uid_write(inode, le32_to_cpu(die->i_uid));
+ i_gid_write(inode, le32_to_cpu(die->i_gid));
+ set_nlink(inode, le32_to_cpu(die->i_nlink));
+ inode_set_mtime(inode, le64_to_cpu(die->i_mtime),
+ le32_to_cpu(die->i_mtime_nsec));
+
+ inode->i_size = le64_to_cpu(die->i_size);
+ break;
+ case EROFS_INODE_LAYOUT_COMPACT:
+ vi->inode_isize = sizeof(struct erofs_inode_compact);
+ ofs += vi->inode_isize;
+ vi->xattr_isize = erofs_xattr_ibody_size(dic->i_xattr_icount);
+
+ inode->i_mode = le16_to_cpu(dic->i_mode);
+ copied.i_u = dic->i_u;
+ i_uid_write(inode, le16_to_cpu(dic->i_uid));
+ i_gid_write(inode, le16_to_cpu(dic->i_gid));
+ if (!S_ISDIR(inode->i_mode) &&
+ ((ifmt >> EROFS_I_NLINK_1_BIT) & 1)) {
+ set_nlink(inode, 1);
+ copied.i_nb = dic->i_nb;
+ } else {
+ set_nlink(inode, le16_to_cpu(dic->i_nb.nlink));
+ copied.i_nb.startblk_hi = 0;
+ addrmask = BIT_ULL(32) - 1;
+ }
+ inode_set_mtime(inode, sbi->epoch + le32_to_cpu(dic->i_mtime),
+ sbi->fixed_nsec);
+
+ inode->i_size = le32_to_cpu(dic->i_size);
+ break;
+ default:
+ erofs_err(sb, "unsupported on-disk inode version %u of nid %llu",
+ erofs_inode_version(ifmt), vi->nid);
+ err = -EOPNOTSUPP;
+ goto err_out;
+ }
+
+ if (unlikely(inode->i_size < 0)) {
+ erofs_err(sb, "negative i_size @ nid %llu", vi->nid);
+ err = -EFSCORRUPTED;
+ goto err_out;
+ }
+
+ if (IS_ENABLED(CONFIG_EROFS_FS_POSIX_ACL) &&
+ erofs_inode_has_noacl(inode, ptr, ofs))
+ cache_no_acl(inode);
+
+ switch (inode->i_mode & S_IFMT) {
+ case S_IFDIR:
+ vi->dot_omitted = (ifmt >> EROFS_I_DOT_OMITTED_BIT) & 1;
+ fallthrough;
+ case S_IFREG:
+ case S_IFLNK:
+ vi->startblk = le32_to_cpu(copied.i_u.startblk_lo) |
+ ((u64)le16_to_cpu(copied.i_nb.startblk_hi) << 32);
+ if (vi->datalayout == EROFS_INODE_FLAT_PLAIN &&
+ !((vi->startblk ^ EROFS_NULL_ADDR) & addrmask))
+ vi->startblk = EROFS_NULL_ADDR;
+
+ if(S_ISLNK(inode->i_mode)) {
+ err = erofs_fill_symlink(inode, ptr, ofs);
+ if (err)
+ goto err_out;
+ }
+ break;
+ case S_IFCHR:
+ case S_IFBLK:
+ inode->i_rdev = new_decode_dev(le32_to_cpu(copied.i_u.rdev));
+ break;
+ case S_IFIFO:
+ case S_IFSOCK:
+ inode->i_rdev = 0;
+ break;
+ default:
+ erofs_err(sb, "bogus i_mode (%o) @ nid %llu", inode->i_mode,
+ vi->nid);
+ err = -EFSCORRUPTED;
+ goto err_out;
+ }
+
+ if (!erofs_inode_is_data_compressed(vi->datalayout)) {
+ inode->i_blocks = round_up(inode->i_size, sb->s_blocksize) >> 9;
+ } else if (!IS_ENABLED(CONFIG_EROFS_FS_ZIP) || !sbi->available_compr_algs) {
+ erofs_err(sb, "compressed inode (nid %llu) is invalid in a plain filesystem",
+ vi->nid);
+ err = -EFSCORRUPTED;
+ goto err_out;
+ } else {
+ inode->i_blocks = (le32_to_cpu(copied.i_u.blocks_lo) |
+ ((u64)le16_to_cpu(copied.i_nb.blocks_hi) << 32)) <<
+ (sb->s_blocksize_bits - 9);
+ }
+
+ if (vi->datalayout == EROFS_INODE_CHUNK_BASED) {
+ /* fill chunked inode summary info */
+ vi->chunkformat = le16_to_cpu(copied.i_u.c.format);
+ if (vi->chunkformat & ~EROFS_CHUNK_FORMAT_ALL) {
+ erofs_err(sb, "unsupported chunk format %x of nid %llu",
+ vi->chunkformat, vi->nid);
+ err = -EOPNOTSUPP;
+ goto err_out;
+ }
+ vi->chunkbits = sb->s_blocksize_bits +
+ (vi->chunkformat & EROFS_CHUNK_FORMAT_BLKBITS_MASK);
+ }
+ inode_set_atime_to_ts(inode,
+ inode_set_ctime_to_ts(inode, inode_get_mtime(inode)));
+
+ inode->i_flags &= ~S_DAX;
+ if (test_opt(&sbi->opt, DAX_ALWAYS) && S_ISREG(inode->i_mode) &&
+ (vi->datalayout == EROFS_INODE_FLAT_PLAIN ||
+ vi->datalayout == EROFS_INODE_CHUNK_BASED))
+ inode->i_flags |= S_DAX;
+err_out:
+ erofs_put_metabuf(&buf);
+ return err;
+}
+
+static int erofs_fill_inode(struct inode *inode)
+{
+ const struct address_space_operations *aops;
+ int err;
+
+ trace_erofs_fill_inode(inode);
+ err = erofs_read_inode(inode);
+ if (err)
+ return err;
+
+ switch (inode->i_mode & S_IFMT) {
+ case S_IFREG:
+ inode->i_op = &erofs_generic_iops;
+ inode->i_fop = erofs_ishare_fill_inode(inode) ?
+ &erofs_ishare_fops : &erofs_file_fops;
+ break;
+ case S_IFDIR:
+ inode->i_op = &erofs_dir_iops;
+ inode->i_fop = &erofs_dir_fops;
+ inode_nohighmem(inode);
+ break;
+ case S_IFLNK:
+ if (inode->i_link)
+ inode->i_op = &erofs_fast_symlink_iops;
+ else
+ inode->i_op = &erofs_symlink_iops;
+ inode_nohighmem(inode);
+ break;
+ default:
+ inode->i_op = &erofs_generic_iops;
+ init_special_inode(inode, inode->i_mode, inode->i_rdev);
+ return 0;
+ }
+
+ mapping_set_large_folios(inode->i_mapping);
+ aops = erofs_get_aops(inode);
+ if (IS_ERR(aops))
+ return PTR_ERR(aops);
+ inode->i_mapping->a_ops = aops;
+ return 0;
+}
+
+/*
+ * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
+ * so that it will fit.
+ */
+static ino_t erofs_squash_ino(struct super_block *sb, erofs_nid_t nid)
+{
+ u64 ino64 = erofs_nid_to_ino64(EROFS_SB(sb), nid);
+
+ if (sizeof(ino_t) < sizeof(erofs_nid_t))
+ ino64 ^= ino64 >> (sizeof(erofs_nid_t) - sizeof(ino_t)) * 8;
+ return (ino_t)ino64;
+}
+
+static int erofs_iget5_eq(struct inode *inode, void *opaque)
+{
+ return EROFS_I(inode)->nid == *(erofs_nid_t *)opaque;
+}
+
+static int erofs_iget5_set(struct inode *inode, void *opaque)
+{
+ const erofs_nid_t nid = *(erofs_nid_t *)opaque;
+
+ inode->i_ino = erofs_squash_ino(inode->i_sb, nid);
+ EROFS_I(inode)->nid = nid;
+ return 0;
+}
+
+struct inode *erofs_iget(struct super_block *sb, erofs_nid_t nid)
+{
+ struct inode *inode;
+
+ inode = iget5_locked(sb, erofs_squash_ino(sb, nid), erofs_iget5_eq,
+ erofs_iget5_set, &nid);
+ if (!inode)
+ return ERR_PTR(-ENOMEM);
+
+ if (inode_state_read_once(inode) & I_NEW) {
+ int err = erofs_fill_inode(inode);
+
+ if (err) {
+ iget_failed(inode);
+ return ERR_PTR(err);
+ }
+ unlock_new_inode(inode);
+ }
+ return inode;
+}
+
+int erofs_getattr(struct mnt_idmap *idmap, const struct path *path,
+ struct kstat *stat, u32 request_mask,
+ unsigned int query_flags)
+{
+ struct inode *const inode = d_inode(path->dentry);
+ struct block_device *bdev = inode->i_sb->s_bdev;
+ bool compressed =
+ erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout);
+
+ if (compressed)
+ stat->attributes |= STATX_ATTR_COMPRESSED;
+ stat->attributes |= STATX_ATTR_IMMUTABLE;
+ stat->attributes_mask |= (STATX_ATTR_COMPRESSED |
+ STATX_ATTR_IMMUTABLE);
+
+ /*
+ * Return the DIO alignment restrictions if requested.
+ *
+ * In EROFS, STATX_DIOALIGN is only supported in bdev-based mode
+ * and uncompressed inodes, otherwise we report no DIO support.
+ */
+ if ((request_mask & STATX_DIOALIGN) && S_ISREG(inode->i_mode)) {
+ stat->result_mask |= STATX_DIOALIGN;
+ if (bdev && !compressed) {
+ stat->dio_mem_align = bdev_dma_alignment(bdev) + 1;
+ stat->dio_offset_align = bdev_logical_block_size(bdev);
+ }
+ }
+ generic_fillattr(idmap, request_mask, inode, stat);
+ return 0;
+}
+
+static int erofs_ioctl_get_volume_label(struct inode *inode, void __user *arg)
+{
+ struct erofs_sb_info *sbi = EROFS_I_SB(inode);
+ int ret;
+
+ if (!sbi->volume_name)
+ ret = clear_user(arg, 1);
+ else
+ ret = copy_to_user(arg, sbi->volume_name,
+ strlen(sbi->volume_name) + 1);
+ return ret ? -EFAULT : 0;
+}
+
+long erofs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+ struct inode *inode = file_inode(filp);
+ void __user *argp = (void __user *)arg;
+
+ switch (cmd) {
+ case FS_IOC_GETFSLABEL:
+ return erofs_ioctl_get_volume_label(inode, argp);
+ default:
+ return -ENOTTY;
+ }
+}
+
+#ifdef CONFIG_COMPAT
+long erofs_compat_ioctl(struct file *filp, unsigned int cmd,
+ unsigned long arg)
+{
+ return erofs_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+const struct inode_operations erofs_generic_iops = {
+ .getattr = erofs_getattr,
+ .listxattr = erofs_listxattr,
+ .get_inode_acl = erofs_get_acl,
+ .fiemap = erofs_fiemap,
+};
+
+const struct inode_operations erofs_symlink_iops = {
+ .get_link = page_get_link,
+ .getattr = erofs_getattr,
+ .listxattr = erofs_listxattr,
+ .get_inode_acl = erofs_get_acl,
+};
+
+const struct inode_operations erofs_fast_symlink_iops = {
+ .get_link = simple_get_link,
+ .getattr = erofs_getattr,
+ .listxattr = erofs_listxattr,
+ .get_inode_acl = erofs_get_acl,
+};
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
new file mode 100644
index 000000000..9b7370f0f
--- /dev/null
+++ b/fs/erofs/internal.h
@@ -0,0 +1,539 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ * https://www.huawei.com/
+ * Copyright (C) 2021, Alibaba Cloud
+ */
+#ifndef __EROFS_INTERNAL_H
+#define __EROFS_INTERNAL_H
+
+#include <linux/fs.h>
+#include <linux/dax.h>
+#include <linux/dcache.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/pagemap.h>
+#include <linux/bio.h>
+#include <linux/magic.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/iomap.h>
+#include "erofs_fs.h"
+
+__printf(2, 3) void _erofs_printk(struct super_block *sb, const char *fmt, ...);
+#define erofs_err(sb, fmt, ...) \
+ _erofs_printk(sb, KERN_ERR fmt "\n", ##__VA_ARGS__)
+#define erofs_warn(sb, fmt, ...) \
+ _erofs_printk(sb, KERN_WARNING fmt "\n", ##__VA_ARGS__)
+#define erofs_info(sb, fmt, ...) \
+ _erofs_printk(sb, KERN_INFO fmt "\n", ##__VA_ARGS__)
+
+#ifdef CONFIG_EROFS_FS_DEBUG
+#define DBG_BUGON BUG_ON
+#else
+#define DBG_BUGON(x) ((void)(x))
+#endif /* !CONFIG_EROFS_FS_DEBUG */
+
+/* EROFS_SUPER_MAGIC_V1 to represent the whole file system */
+#define EROFS_SUPER_MAGIC EROFS_SUPER_MAGIC_V1
+
+typedef u64 erofs_nid_t;
+typedef u64 erofs_off_t;
+typedef u64 erofs_blk_t;
+
+struct erofs_device_info {
+ char *path;
+ struct file *file;
+ struct dax_device *dax_dev;
+ u64 fsoff, dax_part_off;
+
+ erofs_blk_t blocks;
+ erofs_blk_t uniaddr;
+};
+
+enum {
+ EROFS_SYNC_DECOMPRESS_AUTO,
+ EROFS_SYNC_DECOMPRESS_FORCE_ON,
+ EROFS_SYNC_DECOMPRESS_FORCE_OFF
+};
+
+struct erofs_mount_opts {
+ /* current strategy of how to use managed cache */
+ unsigned char cache_strategy;
+ unsigned int mount_opt;
+};
+
+struct erofs_dev_context {
+ struct idr tree;
+ struct rw_semaphore rwsem;
+
+ unsigned int extra_devices;
+ bool flatdev;
+};
+
+/* all filesystem-wide lz4 configurations */
+struct erofs_sb_lz4_info {
+ /* # of pages needed for EROFS lz4 rolling decompression */
+ u16 max_distance_pages;
+ /* maximum possible blocks for pclusters in the filesystem */
+ u16 max_pclusterblks;
+};
+
+struct erofs_xattr_prefix_item {
+ struct erofs_xattr_long_prefix *prefix;
+ u8 infix_len;
+};
+
+struct erofs_sb_info {
+ struct erofs_device_info dif0;
+ struct erofs_mount_opts opt; /* options */
+#ifdef CONFIG_EROFS_FS_ZIP
+ /* list for all registered superblocks, mainly for shrinker */
+ struct list_head list;
+ struct mutex umount_mutex;
+
+ /* managed XArray arranged in physical block number */
+ struct xarray managed_pslots;
+
+ unsigned int sync_decompress; /* strategy for sync decompression */
+ unsigned int shrinker_run_no;
+
+ struct erofs_sb_lz4_info lz4;
+#endif /* CONFIG_EROFS_FS_ZIP */
+ struct inode *managed_cache; /* pseudo inode to cache physical data */
+ struct inode *packed_inode;
+ struct inode *metabox_inode;
+ struct erofs_dev_context *devs;
+ u64 total_blocks;
+
+ u32 meta_blkaddr;
+#ifdef CONFIG_EROFS_FS_XATTR
+ u32 xattr_blkaddr;
+ u32 xattr_prefix_start;
+ u8 xattr_prefix_count;
+ u8 ishare_xattr_prefix_id;
+ struct erofs_xattr_prefix_item *xattr_prefixes;
+ unsigned int xattr_filter_reserved;
+#endif
+ u16 device_id_mask; /* valid bits of device id to be used */
+
+ unsigned char islotbits; /* inode slot unit size in bit shift */
+ unsigned char blkszbits; /* filesystem block size in bit shift */
+
+ u32 sb_size; /* total superblock size */
+ u32 fixed_nsec;
+ s64 epoch;
+
+ /* what we really care is nid, rather than ino.. */
+ erofs_nid_t root_nid;
+ erofs_nid_t packed_nid;
+ erofs_nid_t metabox_nid;
+ /* used for statfs, f_files - f_favail */
+ u64 inos;
+
+ char *volume_name;
+ u32 feature_compat;
+ u32 feature_incompat;
+ u16 available_compr_algs;
+
+ /* sysfs support */
+ struct kobject s_kobj; /* /sys/fs/erofs/<devname> */
+ struct completion s_kobj_unregister;
+ erofs_off_t dir_ra_bytes;
+
+ char *domain_id;
+};
+
+#define EROFS_SB(sb) ((struct erofs_sb_info *)(sb)->s_fs_info)
+#define EROFS_I_SB(inode) ((struct erofs_sb_info *)(inode)->i_sb->s_fs_info)
+
+/* Mount flags set via mount options or defaults */
+#define EROFS_MOUNT_XATTR_USER 0x00000010
+#define EROFS_MOUNT_POSIX_ACL 0x00000020
+#define EROFS_MOUNT_DAX_ALWAYS 0x00000040
+#define EROFS_MOUNT_DAX_NEVER 0x00000080
+#define EROFS_MOUNT_DIRECT_IO 0x00000100
+#define EROFS_MOUNT_INODE_SHARE 0x00000200
+
+#define clear_opt(opt, option) ((opt)->mount_opt &= ~EROFS_MOUNT_##option)
+#define set_opt(opt, option) ((opt)->mount_opt |= EROFS_MOUNT_##option)
+#define test_opt(opt, option) ((opt)->mount_opt & EROFS_MOUNT_##option)
+
+static inline bool erofs_is_fileio_mode(struct erofs_sb_info *sbi)
+{
+ return IS_ENABLED(CONFIG_EROFS_FS_BACKED_BY_FILE) && sbi->dif0.file;
+}
+
+extern struct file_system_type erofs_anon_fs_type;
+
+enum {
+ EROFS_ZIP_CACHE_DISABLED,
+ EROFS_ZIP_CACHE_READAHEAD,
+ EROFS_ZIP_CACHE_READAROUND
+};
+
+struct erofs_buf {
+ struct address_space *mapping;
+ u64 off;
+ struct page *page;
+ void *base;
+ bool mc;
+};
+#define __EROFS_BUF_INITIALIZER ((struct erofs_buf){ .page = NULL })
+
+#define erofs_blknr(sb, pos) ((erofs_blk_t)((pos) >> (sb)->s_blocksize_bits))
+#define erofs_blkoff(sb, pos) ((pos) & ((sb)->s_blocksize - 1))
+#define erofs_pos(sb, blk) ((erofs_off_t)(blk) << (sb)->s_blocksize_bits)
+#define erofs_iblks(i) (round_up((i)->i_size, i_blocksize(i)) >> (i)->i_blkbits)
+
+#define EROFS_FEATURE_FUNCS(name, compat, feature) \
+static inline bool erofs_sb_has_##name(struct erofs_sb_info *sbi) \
+{ \
+ return sbi->feature_##compat & EROFS_FEATURE_##feature; \
+}
+
+EROFS_FEATURE_FUNCS(lz4_0padding, incompat, INCOMPAT_LZ4_0PADDING)
+EROFS_FEATURE_FUNCS(compr_cfgs, incompat, INCOMPAT_COMPR_CFGS)
+EROFS_FEATURE_FUNCS(big_pcluster, incompat, INCOMPAT_BIG_PCLUSTER)
+EROFS_FEATURE_FUNCS(chunked_file, incompat, INCOMPAT_CHUNKED_FILE)
+EROFS_FEATURE_FUNCS(device_table, incompat, INCOMPAT_DEVICE_TABLE)
+EROFS_FEATURE_FUNCS(compr_head2, incompat, INCOMPAT_COMPR_HEAD2)
+EROFS_FEATURE_FUNCS(ztailpacking, incompat, INCOMPAT_ZTAILPACKING)
+EROFS_FEATURE_FUNCS(fragments, incompat, INCOMPAT_FRAGMENTS)
+EROFS_FEATURE_FUNCS(dedupe, incompat, INCOMPAT_DEDUPE)
+EROFS_FEATURE_FUNCS(xattr_prefixes, incompat, INCOMPAT_XATTR_PREFIXES)
+EROFS_FEATURE_FUNCS(48bit, incompat, INCOMPAT_48BIT)
+EROFS_FEATURE_FUNCS(metabox, incompat, INCOMPAT_METABOX)
+EROFS_FEATURE_FUNCS(sb_chksum, compat, COMPAT_SB_CHKSUM)
+EROFS_FEATURE_FUNCS(xattr_filter, compat, COMPAT_XATTR_FILTER)
+EROFS_FEATURE_FUNCS(shared_ea_in_metabox, compat, COMPAT_SHARED_EA_IN_METABOX)
+EROFS_FEATURE_FUNCS(plain_xattr_pfx, compat, COMPAT_PLAIN_XATTR_PFX)
+EROFS_FEATURE_FUNCS(ishare_xattrs, compat, COMPAT_ISHARE_XATTRS)
+
+static inline u64 erofs_nid_to_ino64(struct erofs_sb_info *sbi, erofs_nid_t nid)
+{
+ if (!erofs_sb_has_metabox(sbi))
+ return nid;
+
+ /*
+ * When metadata compression is enabled, avoid generating excessively
+ * large inode numbers for metadata-compressed inodes. Shift NIDs in
+ * the 31-62 bit range left by one and move the metabox flag to bit 31.
+ *
+ * Note: on-disk NIDs remain unchanged as they are primarily used for
+ * compatibility with non-LFS 32-bit applications.
+ */
+ return ((nid << 1) & GENMASK_ULL(63, 32)) | (nid & GENMASK(30, 0)) |
+ ((nid >> EROFS_DIRENT_NID_METABOX_BIT) << 31);
+}
+
+/* atomic flag definitions */
+#define EROFS_I_EA_INITED_BIT 0
+#define EROFS_I_Z_INITED_BIT 1
+
+/* bitlock definitions (arranged in reverse order) */
+#define EROFS_I_BL_XATTR_BIT (BITS_PER_LONG - 1)
+#define EROFS_I_BL_Z_BIT (BITS_PER_LONG - 2)
+
+/* default readahead size of directories */
+#define EROFS_DIR_RA_BYTES 16384
+
+struct erofs_inode_fingerprint {
+ u8 *opaque;
+ int size;
+};
+
+struct erofs_inode {
+ erofs_nid_t nid;
+
+ /* atomic flags (including bitlocks) */
+ unsigned long flags;
+
+ unsigned char datalayout;
+ unsigned char inode_isize;
+ bool dot_omitted;
+ unsigned int xattr_isize;
+
+ unsigned int xattr_name_filter;
+ unsigned int xattr_shared_count;
+ unsigned int *xattr_shared_xattrs;
+
+ union {
+ erofs_blk_t startblk;
+ struct {
+ unsigned short chunkformat;
+ unsigned char chunkbits;
+ };
+#ifdef CONFIG_EROFS_FS_ZIP
+ struct {
+ unsigned short z_advise;
+ unsigned char z_algofmt[2];
+ unsigned char z_lclusterbits;
+ union {
+ u64 z_tailextent_headlcn;
+ u64 z_extents;
+ };
+ erofs_off_t z_fragmentoff;
+ unsigned short z_idata_size;
+ };
+#endif /* CONFIG_EROFS_FS_ZIP */
+ };
+#ifdef CONFIG_EROFS_FS_PAGE_CACHE_SHARE
+ struct list_head ishare_list;
+ union {
+ /* for each anon shared inode */
+ struct {
+ struct erofs_inode_fingerprint fingerprint;
+ spinlock_t ishare_lock;
+ };
+ /* for each real filesystem inode */
+ struct dentry *sharedentry;
+ };
+#endif
+ /* the corresponding vfs inode */
+ struct inode vfs_inode;
+};
+
+#define EROFS_I(ptr) container_of(ptr, struct erofs_inode, vfs_inode)
+
+static inline bool erofs_inode_in_metabox(struct inode *inode)
+{
+ return EROFS_I(inode)->nid & BIT_ULL(EROFS_DIRENT_NID_METABOX_BIT);
+}
+
+static inline erofs_off_t erofs_iloc(struct inode *inode)
+{
+ struct erofs_sb_info *sbi = EROFS_I_SB(inode);
+ erofs_nid_t nid_lo = EROFS_I(inode)->nid & EROFS_DIRENT_NID_MASK;
+
+ if (erofs_inode_in_metabox(inode))
+ return nid_lo << sbi->islotbits;
+ return erofs_pos(inode->i_sb, sbi->meta_blkaddr) +
+ (nid_lo << sbi->islotbits);
+}
+
+static inline unsigned int erofs_inode_version(unsigned int ifmt)
+{
+ return (ifmt >> EROFS_I_VERSION_BIT) & EROFS_I_VERSION_MASK;
+}
+
+static inline unsigned int erofs_inode_datalayout(unsigned int ifmt)
+{
+ return (ifmt >> EROFS_I_DATALAYOUT_BIT) & EROFS_I_DATALAYOUT_MASK;
+}
+
+/* reclaiming is never triggered when allocating new folios. */
+static inline struct folio *erofs_grab_folio_nowait(struct address_space *as,
+ pgoff_t index)
+{
+ return __filemap_get_folio(as, index,
+ FGP_LOCK|FGP_CREAT|FGP_NOFS|FGP_NOWAIT,
+ readahead_gfp_mask(as) & ~__GFP_RECLAIM);
+}
+
+/* Allocated on disk at @m_pa (e.g. NOT a fragment extent) */
+#define EROFS_MAP_MAPPED 0x0001
+/* Located in metadata (could be copied from bd_inode) */
+#define EROFS_MAP_META 0x0002
+/* @m_llen may be truncated by the runtime compared to the on-disk record */
+#define EROFS_MAP_PARTIAL_MAPPED 0x0004
+/* The on-disk @m_llen may cover only part of the encoded data */
+#define EROFS_MAP_PARTIAL_REF 0x0008
+/* Located in the special packed inode */
+#define EROFS_MAP_FRAGMENT 0x0010
+/* The encoded on-disk data will be fully handled (decompressed) */
+#define EROFS_MAP_FULL(f) (!((f) & (EROFS_MAP_PARTIAL_MAPPED | \
+ EROFS_MAP_PARTIAL_REF)))
+
+struct erofs_map_blocks {
+ struct erofs_buf buf;
+
+ erofs_off_t m_pa, m_la;
+ u64 m_plen, m_llen;
+
+ unsigned short m_deviceid;
+ char m_algorithmformat;
+ unsigned int m_flags;
+};
+
+/*
+ * Used to get the exact decompressed length, e.g. fiemap (consider lookback
+ * approach instead if possible since it's more metadata lightweight.)
+ */
+#define EROFS_GET_BLOCKS_FIEMAP 0x0001
+/* Used to map the whole extent if non-negligible data is requested for LZMA */
+#define EROFS_GET_BLOCKS_READMORE 0x0002
+/* Used to map tail extent for tailpacking inline or fragment pcluster */
+#define EROFS_GET_BLOCKS_FINDTAIL 0x0004
+
+enum {
+ Z_EROFS_COMPRESSION_SHIFTED = Z_EROFS_COMPRESSION_MAX,
+ Z_EROFS_COMPRESSION_INTERLACED,
+ Z_EROFS_COMPRESSION_RUNTIME_MAX
+};
+
+struct erofs_map_dev {
+ struct super_block *m_sb;
+ struct erofs_device_info *m_dif;
+ struct block_device *m_bdev;
+
+ erofs_off_t m_pa;
+ unsigned int m_deviceid;
+};
+
+extern const struct super_operations erofs_sops;
+extern const struct address_space_operations erofs_aops;
+extern const struct address_space_operations erofs_fileio_aops;
+extern const struct address_space_operations z_erofs_aops;
+
+extern const struct inode_operations erofs_generic_iops;
+extern const struct inode_operations erofs_symlink_iops;
+extern const struct inode_operations erofs_fast_symlink_iops;
+extern const struct inode_operations erofs_dir_iops;
+
+extern const struct file_operations erofs_file_fops;
+extern const struct file_operations erofs_dir_fops;
+extern const struct file_operations erofs_ishare_fops;
+
+extern const struct iomap_ops z_erofs_iomap_report_ops;
+
+int erofs_setup_managed_cache(struct super_block *sb);
+#ifdef CONFIG_EROFS_FS_BACKED_BY_FILE
+int erofs_read_meta_folio(struct file *file, struct folio *folio);
+#else
+#define erofs_read_meta_folio NULL
+#endif
+void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf,
+ erofs_off_t *offset, int *lengthp);
+void erofs_unmap_metabuf(struct erofs_buf *buf);
+void erofs_put_metabuf(struct erofs_buf *buf);
+void *erofs_bread(struct erofs_buf *buf, erofs_off_t offset, bool need_kmap);
+int erofs_init_metabuf(struct erofs_buf *buf, struct super_block *sb,
+ bool in_metabox);
+void *erofs_read_metabuf(struct erofs_buf *buf, struct super_block *sb,
+ erofs_off_t offset, bool in_metabox);
+int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *dev);
+int erofs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
+ u64 start, u64 len);
+int erofs_map_blocks(struct inode *inode, struct erofs_map_blocks *map);
+void erofs_onlinefolio_init(struct folio *folio);
+void erofs_onlinefolio_split(struct folio *folio);
+void erofs_onlinefolio_end(struct folio *folio, int err, bool dirty);
+struct inode *erofs_iget(struct super_block *sb, erofs_nid_t nid);
+int erofs_getattr(struct mnt_idmap *idmap, const struct path *path,
+ struct kstat *stat, u32 request_mask,
+ unsigned int query_flags);
+int erofs_namei(struct inode *dir, const struct qstr *name,
+ erofs_nid_t *nid, unsigned int *d_type);
+
+static inline void *erofs_vm_map_ram(struct page **pages, unsigned int count)
+{
+ int retried = 0;
+
+ while (1) {
+ void *p = vm_map_ram(pages, count, -1);
+
+ /* retry two more times (totally 3 times) */
+ if (p || ++retried >= 3)
+ return p;
+ vm_unmap_aliases();
+ }
+ return NULL;
+}
+
+static inline const struct address_space_operations *
+erofs_get_aops(struct inode *realinode)
+{
+ if (erofs_inode_is_data_compressed(EROFS_I(realinode)->datalayout)) {
+ if (!IS_ENABLED(CONFIG_EROFS_FS_ZIP))
+ return ERR_PTR(-EOPNOTSUPP);
+ DO_ONCE_LITE_IF(realinode->i_blkbits != PAGE_SHIFT,
+ erofs_info, realinode->i_sb,
+ "EXPERIMENTAL EROFS subpage compressed block support in use. Use at your own risk!");
+ return &z_erofs_aops;
+ }
+ if (IS_ENABLED(CONFIG_EROFS_FS_BACKED_BY_FILE) &&
+ erofs_is_fileio_mode(EROFS_SB(realinode->i_sb)))
+ return &erofs_fileio_aops;
+ return &erofs_aops;
+}
+
+int erofs_register_sysfs(struct super_block *sb);
+void erofs_unregister_sysfs(struct super_block *sb);
+int __init erofs_init_sysfs(void);
+void erofs_exit_sysfs(void);
+
+struct page *__erofs_allocpage(struct page **pagepool, gfp_t gfp, bool tryrsv);
+static inline struct page *erofs_allocpage(struct page **pagepool, gfp_t gfp)
+{
+ return __erofs_allocpage(pagepool, gfp, false);
+}
+static inline void erofs_pagepool_add(struct page **pagepool, struct page *page)
+{
+ set_page_private(page, (unsigned long)*pagepool);
+ *pagepool = page;
+}
+void erofs_release_pages(struct page **pagepool);
+
+#ifdef CONFIG_EROFS_FS_ZIP
+#define MNGD_MAPPING(sbi) ((sbi)->managed_cache->i_mapping)
+
+extern atomic_long_t erofs_global_shrink_cnt;
+void erofs_shrinker_register(struct super_block *sb);
+void erofs_shrinker_unregister(struct super_block *sb);
+int __init erofs_init_shrinker(void);
+void erofs_exit_shrinker(void);
+int __init z_erofs_init_subsystem(void);
+void z_erofs_exit_subsystem(void);
+int z_erofs_init_super(struct super_block *sb);
+unsigned long z_erofs_shrink_scan(struct erofs_sb_info *sbi,
+ unsigned long nr_shrink);
+int z_erofs_map_blocks_iter(struct inode *inode, struct erofs_map_blocks *map,
+ int flags);
+void *z_erofs_get_gbuf(unsigned int requiredpages);
+void z_erofs_put_gbuf(void *ptr);
+int z_erofs_gbuf_growsize(unsigned int nrpages);
+int __init z_erofs_gbuf_init(void);
+void z_erofs_gbuf_exit(void);
+#else
+static inline void erofs_shrinker_register(struct super_block *sb) {}
+static inline void erofs_shrinker_unregister(struct super_block *sb) {}
+static inline int erofs_init_shrinker(void) { return 0; }
+static inline void erofs_exit_shrinker(void) {}
+static inline int z_erofs_init_subsystem(void) { return 0; }
+static inline void z_erofs_exit_subsystem(void) {}
+static inline int z_erofs_init_super(struct super_block *sb) { return 0; }
+#endif /* !CONFIG_EROFS_FS_ZIP */
+int z_erofs_parse_cfgs(struct super_block *sb, struct erofs_super_block *dsb);
+
+#ifdef CONFIG_EROFS_FS_BACKED_BY_FILE
+struct bio *erofs_fileio_bio_alloc(struct erofs_map_dev *mdev);
+void erofs_fileio_submit_bio(struct bio *bio);
+#else
+static inline struct bio *erofs_fileio_bio_alloc(struct erofs_map_dev *mdev) { return NULL; }
+static inline void erofs_fileio_submit_bio(struct bio *bio) {}
+#endif
+
+#ifdef CONFIG_EROFS_FS_PAGE_CACHE_SHARE
+int __init erofs_init_ishare(void);
+void erofs_exit_ishare(void);
+bool erofs_ishare_fill_inode(struct inode *inode);
+void erofs_ishare_free_inode(struct inode *inode);
+struct inode *erofs_real_inode(struct inode *inode, bool *need_iput);
+#else
+static inline int erofs_init_ishare(void) { return 0; }
+static inline void erofs_exit_ishare(void) {}
+static inline bool erofs_ishare_fill_inode(struct inode *inode) { return false; }
+static inline void erofs_ishare_free_inode(struct inode *inode) {}
+static inline struct inode *erofs_real_inode(struct inode *inode, bool *need_iput)
+{
+ *need_iput = false;
+ return inode;
+}
+#endif
+
+long erofs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
+long erofs_compat_ioctl(struct file *filp, unsigned int cmd,
+ unsigned long arg);
+
+#endif /* __EROFS_INTERNAL_H */
diff --git a/fs/erofs/ishare.c b/fs/erofs/ishare.c
new file mode 100644
index 000000000..fa7d4112d
--- /dev/null
+++ b/fs/erofs/ishare.c
@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2024, Alibaba Cloud
+ */
+#include <linux/backing-file.h>
+#include <linux/xxhash.h>
+#include <linux/mount.h>
+#include <linux/security.h>
+#include "internal.h"
+#include "xattr.h"
+
+static struct vfsmount *erofs_ishare_mnt;
+
+static int erofs_ishare_iget5_eq(struct inode *inode, void *data)
+{
+ struct erofs_inode_fingerprint *fp1 = &EROFS_I(inode)->fingerprint;
+ struct erofs_inode_fingerprint *fp2 = data;
+
+ return fp1->size == fp2->size &&
+ !memcmp(fp1->opaque, fp2->opaque, fp2->size);
+}
+
+static int erofs_ishare_iget5_set(struct inode *inode, void *data)
+{
+ struct erofs_inode *vi = EROFS_I(inode);
+
+ vi->fingerprint = *(struct erofs_inode_fingerprint *)data;
+ INIT_LIST_HEAD(&vi->ishare_list);
+ spin_lock_init(&vi->ishare_lock);
+ return 0;
+}
+
+bool erofs_ishare_fill_inode(struct inode *inode)
+{
+ static const struct file_operations empty_fops = {};
+ struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
+ const struct address_space_operations *aops;
+ struct erofs_inode *vi = EROFS_I(inode);
+ struct erofs_inode_fingerprint fp;
+ struct dentry *sd;
+ struct inode *si;
+
+ aops = erofs_get_aops(inode);
+ if (IS_ERR(aops))
+ return false;
+ if (erofs_xattr_fill_inode_fingerprint(&fp, inode, sbi->domain_id))
+ return false;
+
+ si = iget5_locked(erofs_ishare_mnt->mnt_sb,
+ xxh32(fp.opaque, fp.size, 0),
+ erofs_ishare_iget5_eq, erofs_ishare_iget5_set, &fp);
+ if (si && (inode_state_read_once(si) & I_NEW)) {
+ si->i_fop = &empty_fops;
+ si->i_mapping->a_ops = aops;
+ si->i_mode = 0444 | S_IFREG;
+ si->i_size = inode->i_size;
+ unlock_new_inode(si);
+ } else {
+ kfree(fp.opaque);
+ if (!si || aops != si->i_mapping->a_ops) {
+ iput(si);
+ return false;
+ }
+ if (si->i_size != inode->i_size) {
+ erofs_warn(inode->i_sb, "i_size mismatch (%lld != %lld) for the same fingerprint",
+ inode->i_size, si->i_size);
+ iput(si);
+ return false;
+ }
+ }
+ sd = d_obtain_alias(si); /* disconnected denties for sharedinodes */
+ if (IS_ERR(sd))
+ return false;
+ vi->sharedentry = sd;
+ INIT_LIST_HEAD(&vi->ishare_list);
+ spin_lock(&EROFS_I(si)->ishare_lock);
+ list_add(&vi->ishare_list, &EROFS_I(si)->ishare_list);
+ spin_unlock(&EROFS_I(si)->ishare_lock);
+ return true;
+}
+
+void erofs_ishare_free_inode(struct inode *inode)
+{
+ struct erofs_inode *vi = EROFS_I(inode), *svi;
+
+ if (!vi->sharedentry)
+ return;
+ svi = EROFS_I(d_inode(vi->sharedentry));
+ spin_lock(&svi->ishare_lock);
+ list_del(&vi->ishare_list);
+ spin_unlock(&svi->ishare_lock);
+ dput(vi->sharedentry);
+ vi->sharedentry = NULL;
+}
+
+static int erofs_ishare_file_open(struct inode *inode, struct file *file)
+{
+ struct path sharedpath = {
+ .mnt = erofs_ishare_mnt,
+ .dentry = EROFS_I(inode)->sharedentry,
+ };
+ struct file *rf;
+
+ if (file->f_flags & O_DIRECT)
+ return -EINVAL;
+
+ rf = backing_file_open(file, file->f_flags | O_NOATIME,
+ &sharedpath, current_cred());
+ if (IS_ERR(rf))
+ return PTR_ERR(rf);
+ file->private_data = rf;
+ return 0;
+}
+
+static int erofs_ishare_file_release(struct inode *inode, struct file *file)
+{
+ fput(file->private_data);
+ file->private_data = NULL;
+ return 0;
+}
+
+static ssize_t erofs_ishare_file_read_iter(struct kiocb *iocb,
+ struct iov_iter *to)
+{
+ struct file *realfile = iocb->ki_filp->private_data;
+ struct kiocb dedup_iocb;
+ ssize_t nread;
+
+ if (!iov_iter_count(to))
+ return 0;
+ kiocb_clone(&dedup_iocb, iocb, realfile);
+ nread = filemap_read(&dedup_iocb, to, 0);
+ iocb->ki_pos = dedup_iocb.ki_pos;
+ return nread;
+}
+
+static int erofs_ishare_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ struct file *realfile = file->private_data;
+ int err;
+
+ vma_set_file(vma, realfile);
+
+ err = security_mmap_backing_file(vma, realfile, file);
+ if (err)
+ return err;
+
+ return generic_file_readonly_mmap(file, vma);
+}
+
+static int erofs_ishare_fadvise(struct file *file, loff_t offset,
+ loff_t len, int advice)
+{
+ return vfs_fadvise(file->private_data, offset, len, advice);
+}
+
+const struct file_operations erofs_ishare_fops = {
+ .open = erofs_ishare_file_open,
+ .llseek = generic_file_llseek,
+ .read_iter = erofs_ishare_file_read_iter,
+ .mmap = erofs_ishare_mmap,
+ .release = erofs_ishare_file_release,
+ .get_unmapped_area = thp_get_unmapped_area,
+ .splice_read = filemap_splice_read,
+ .fadvise = erofs_ishare_fadvise,
+};
+
+struct inode *erofs_real_inode(struct inode *inode, bool *need_iput)
+{
+ struct erofs_inode *vi, *vi_share;
+ struct inode *realinode;
+
+ *need_iput = false;
+ if (inode->i_sb != erofs_ishare_mnt->mnt_sb)
+ return inode;
+
+ vi_share = EROFS_I(inode);
+ spin_lock(&vi_share->ishare_lock);
+ /* fetch any one as real inode */
+ DBG_BUGON(list_empty(&vi_share->ishare_list));
+ list_for_each_entry(vi, &vi_share->ishare_list, ishare_list) {
+ realinode = igrab(&vi->vfs_inode);
+ if (realinode) {
+ *need_iput = true;
+ break;
+ }
+ }
+ spin_unlock(&vi_share->ishare_lock);
+
+ DBG_BUGON(!realinode);
+ return realinode;
+}
+
+int __init erofs_init_ishare(void)
+{
+ struct vfsmount *mnt;
+ int ret;
+
+ mnt = kern_mount(&erofs_anon_fs_type);
+ if (IS_ERR(mnt))
+ return PTR_ERR(mnt);
+ /* generic_fadvise() doesn't work if s_bdi == &noop_backing_dev_info */
+ ret = super_setup_bdi(mnt->mnt_sb);
+ if (ret)
+ kern_unmount(mnt);
+ else
+ erofs_ishare_mnt = mnt;
+ return ret;
+}
+
+void erofs_exit_ishare(void)
+{
+ kern_unmount(erofs_ishare_mnt);
+}
diff --git a/fs/erofs/namei.c b/fs/erofs/namei.c
new file mode 100644
index 000000000..f7cf4f41a
--- /dev/null
+++ b/fs/erofs/namei.c
@@ -0,0 +1,224 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ * https://www.huawei.com/
+ * Copyright (C) 2022, Alibaba Cloud
+ */
+#include "xattr.h"
+#include <trace/events/erofs.h>
+
+struct erofs_qstr {
+ const unsigned char *name;
+ const unsigned char *end;
+};
+
+/* based on the end of qn is accurate and it must have the trailing '\0' */
+static inline int erofs_dirnamecmp(const struct erofs_qstr *qn,
+ const struct erofs_qstr *qd,
+ unsigned int *matched)
+{
+ unsigned int i = *matched;
+
+ /*
+ * on-disk error, let's only BUG_ON in the debugging mode.
+ * otherwise, it will return 1 to just skip the invalid name
+ * and go on (in consideration of the lookup performance).
+ */
+ DBG_BUGON(qd->name > qd->end);
+
+ /* qd could not have trailing '\0' */
+ /* However it is absolutely safe if < qd->end */
+ while (qd->name + i < qd->end && qd->name[i] != '\0') {
+ if (qn->name[i] != qd->name[i]) {
+ *matched = i;
+ return qn->name[i] > qd->name[i] ? 1 : -1;
+ }
+ ++i;
+ }
+ *matched = i;
+ /* See comments in __d_alloc on the terminating NUL character */
+ return qn->name[i] == '\0' ? 0 : 1;
+}
+
+#define nameoff_from_disk(off, sz) (le16_to_cpu(off) & ((sz) - 1))
+
+static struct erofs_dirent *find_target_dirent(struct erofs_qstr *name,
+ u8 *data,
+ unsigned int dirblksize,
+ const int ndirents)
+{
+ int head, back;
+ unsigned int startprfx, endprfx;
+ struct erofs_dirent *const de = (struct erofs_dirent *)data;
+
+ /* since the 1st dirent has been evaluated previously */
+ head = 1;
+ back = ndirents - 1;
+ startprfx = endprfx = 0;
+
+ while (head <= back) {
+ const int mid = head + (back - head) / 2;
+ const int nameoff = nameoff_from_disk(de[mid].nameoff,
+ dirblksize);
+ unsigned int matched = min(startprfx, endprfx);
+ struct erofs_qstr dname = {
+ .name = data + nameoff,
+ .end = mid >= ndirents - 1 ?
+ data + dirblksize :
+ data + nameoff_from_disk(de[mid + 1].nameoff,
+ dirblksize)
+ };
+
+ /* string comparison without already matched prefix */
+ int ret = erofs_dirnamecmp(name, &dname, &matched);
+
+ if (!ret) {
+ return de + mid;
+ } else if (ret > 0) {
+ head = mid + 1;
+ startprfx = matched;
+ } else {
+ back = mid - 1;
+ endprfx = matched;
+ }
+ }
+
+ return ERR_PTR(-ENOENT);
+}
+
+static void *erofs_find_target_block(struct erofs_buf *target,
+ struct inode *dir, struct erofs_qstr *name, int *_ndirents)
+{
+ unsigned int bsz = i_blocksize(dir);
+ int head = 0, back = erofs_iblks(dir) - 1;
+ unsigned int startprfx = 0, endprfx = 0;
+ void *candidate = ERR_PTR(-ENOENT);
+
+ while (head <= back) {
+ const int mid = head + (back - head) / 2;
+ struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+ struct erofs_dirent *de;
+
+ buf.mapping = dir->i_mapping;
+ de = erofs_bread(&buf, erofs_pos(dir->i_sb, mid), true);
+ if (!IS_ERR(de)) {
+ const int nameoff = nameoff_from_disk(de->nameoff, bsz);
+ const int ndirents = nameoff / sizeof(*de);
+ int diff;
+ unsigned int matched;
+ struct erofs_qstr dname;
+
+ if (!ndirents) {
+ erofs_put_metabuf(&buf);
+ erofs_err(dir->i_sb,
+ "corrupted dir block %d @ nid %llu",
+ mid, EROFS_I(dir)->nid);
+ DBG_BUGON(1);
+ de = ERR_PTR(-EFSCORRUPTED);
+ goto out;
+ }
+
+ matched = min(startprfx, endprfx);
+
+ dname.name = (u8 *)de + nameoff;
+ if (ndirents == 1)
+ dname.end = (u8 *)de + bsz;
+ else
+ dname.end = (u8 *)de +
+ nameoff_from_disk(de[1].nameoff, bsz);
+
+ /* string comparison without already matched prefix */
+ diff = erofs_dirnamecmp(name, &dname, &matched);
+
+ if (diff < 0) {
+ erofs_put_metabuf(&buf);
+ back = mid - 1;
+ endprfx = matched;
+ continue;
+ }
+
+ if (!IS_ERR(candidate))
+ erofs_put_metabuf(target);
+ *target = buf;
+ if (!diff) {
+ *_ndirents = 0;
+ return de;
+ }
+ head = mid + 1;
+ startprfx = matched;
+ candidate = de;
+ *_ndirents = ndirents;
+ continue;
+ }
+out: /* free if the candidate is valid */
+ if (!IS_ERR(candidate))
+ erofs_put_metabuf(target);
+ return de;
+ }
+ return candidate;
+}
+
+int erofs_namei(struct inode *dir, const struct qstr *name, erofs_nid_t *nid,
+ unsigned int *d_type)
+{
+ int ndirents;
+ struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+ struct erofs_dirent *de;
+ struct erofs_qstr qn;
+
+ if (!dir->i_size)
+ return -ENOENT;
+
+ qn.name = name->name;
+ qn.end = name->name + name->len;
+ buf.mapping = dir->i_mapping;
+
+ ndirents = 0;
+ de = erofs_find_target_block(&buf, dir, &qn, &ndirents);
+ if (IS_ERR(de))
+ return PTR_ERR(de);
+
+ if (ndirents)
+ de = find_target_dirent(&qn, (u8 *)de, i_blocksize(dir),
+ ndirents);
+
+ if (!IS_ERR(de)) {
+ *nid = le64_to_cpu(de->nid);
+ *d_type = de->file_type;
+ }
+ erofs_put_metabuf(&buf);
+ return PTR_ERR_OR_ZERO(de);
+}
+
+static struct dentry *erofs_lookup(struct inode *dir, struct dentry *dentry,
+ unsigned int flags)
+{
+ int err;
+ erofs_nid_t nid;
+ unsigned int d_type;
+ struct inode *inode;
+
+ trace_erofs_lookup(dir, dentry, flags);
+
+ if (dentry->d_name.len > EROFS_NAME_LEN)
+ return ERR_PTR(-ENAMETOOLONG);
+
+ err = erofs_namei(dir, &dentry->d_name, &nid, &d_type);
+
+ if (err == -ENOENT)
+ /* negative dentry */
+ inode = NULL;
+ else if (err)
+ inode = ERR_PTR(err);
+ else
+ inode = erofs_iget(dir->i_sb, nid);
+ return d_splice_alias(inode, dentry);
+}
+
+const struct inode_operations erofs_dir_iops = {
+ .lookup = erofs_lookup,
+ .getattr = erofs_getattr,
+ .listxattr = erofs_listxattr,
+ .get_inode_acl = erofs_get_acl,
+ .fiemap = erofs_fiemap,
+};
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
new file mode 100644
index 000000000..0967aace9
--- /dev/null
+++ b/fs/erofs/super.c
@@ -0,0 +1,1146 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ * https://www.huawei.com/
+ * Copyright (C) 2021, Alibaba Cloud
+ */
+#include <linux/statfs.h>
+#include <linux/seq_file.h>
+#include <linux/crc32c.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
+#include <linux/exportfs.h>
+#include <linux/backing-dev.h>
+#include <linux/pseudo_fs.h>
+#include "xattr.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/erofs.h>
+
+static struct kmem_cache *erofs_inode_cachep __read_mostly;
+
+void _erofs_printk(struct super_block *sb, const char *fmt, ...)
+{
+ struct va_format vaf;
+ va_list args;
+ int level;
+
+ va_start(args, fmt);
+
+ level = printk_get_level(fmt);
+ vaf.fmt = printk_skip_level(fmt);
+ vaf.va = &args;
+ if (sb)
+ printk("%c%cerofs (device %s): %pV",
+ KERN_SOH_ASCII, level, sb->s_id, &vaf);
+ else
+ printk("%c%cerofs: %pV", KERN_SOH_ASCII, level, &vaf);
+ va_end(args);
+}
+
+static int erofs_superblock_csum_verify(struct super_block *sb, void *sbdata)
+{
+ struct erofs_super_block *dsb = sbdata + EROFS_SUPER_OFFSET;
+ u32 len = 1 << EROFS_SB(sb)->blkszbits, crc;
+
+ if (len > EROFS_SUPER_OFFSET)
+ len -= EROFS_SUPER_OFFSET;
+ len -= offsetof(struct erofs_super_block, checksum) +
+ sizeof(dsb->checksum);
+
+ /* skip .magic(pre-verified) and .checksum(0) fields */
+ crc = crc32c(0x5045B54A, (&dsb->checksum) + 1, len);
+ if (crc == le32_to_cpu(dsb->checksum))
+ return 0;
+ erofs_err(sb, "invalid checksum 0x%08x, 0x%08x expected",
+ crc, le32_to_cpu(dsb->checksum));
+ return -EBADMSG;
+}
+
+static void erofs_inode_init_once(void *ptr)
+{
+ struct erofs_inode *vi = ptr;
+
+ inode_init_once(&vi->vfs_inode);
+}
+
+static struct inode *erofs_alloc_inode(struct super_block *sb)
+{
+ struct erofs_inode *vi =
+ alloc_inode_sb(sb, erofs_inode_cachep, GFP_KERNEL);
+
+ if (!vi)
+ return NULL;
+
+ /* zero out everything except vfs_inode */
+ memset(vi, 0, offsetof(struct erofs_inode, vfs_inode));
+ return &vi->vfs_inode;
+}
+
+static void erofs_free_inode(struct inode *inode)
+{
+ struct erofs_inode *vi = EROFS_I(inode);
+
+ if (inode->i_op == &erofs_fast_symlink_iops)
+ kfree(inode->i_link);
+ kfree(vi->xattr_shared_xattrs);
+ kmem_cache_free(erofs_inode_cachep, vi);
+}
+
+/* read variable-sized metadata, offset will be aligned by 4-byte */
+void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf,
+ erofs_off_t *offset, int *lengthp)
+{
+ u8 *buffer, *ptr;
+ int len, i, cnt;
+
+ *offset = round_up(*offset, 4);
+ ptr = erofs_bread(buf, *offset, true);
+ if (IS_ERR(ptr))
+ return ptr;
+
+ len = le16_to_cpu(*(__le16 *)ptr);
+ if (!len)
+ len = U16_MAX + 1;
+ buffer = kmalloc(len, GFP_KERNEL);
+ if (!buffer)
+ return ERR_PTR(-ENOMEM);
+ *offset += sizeof(__le16);
+ *lengthp = len;
+
+ for (i = 0; i < len; i += cnt) {
+ cnt = min_t(int, sb->s_blocksize - erofs_blkoff(sb, *offset),
+ len - i);
+ ptr = erofs_bread(buf, *offset, true);
+ if (IS_ERR(ptr)) {
+ kfree(buffer);
+ return ptr;
+ }
+ memcpy(buffer + i, ptr, cnt);
+ *offset += cnt;
+ }
+ return buffer;
+}
+
+static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
+ struct erofs_device_info *dif, erofs_off_t *pos)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ struct erofs_deviceslot *dis;
+ struct file *file;
+ bool _48bit;
+
+ dis = erofs_read_metabuf(buf, sb, *pos, false);
+ if (IS_ERR(dis))
+ return PTR_ERR(dis);
+
+ if (!sbi->devs->flatdev && !dif->path) {
+ if (!dis->tag[0]) {
+ erofs_err(sb, "empty device tag @ pos %llu", *pos);
+ return -EINVAL;
+ }
+ dif->path = kmemdup_nul(dis->tag, sizeof(dis->tag), GFP_KERNEL);
+ if (!dif->path)
+ return -ENOMEM;
+ }
+
+ if (!sbi->devs->flatdev) {
+ file = erofs_is_fileio_mode(sbi) ?
+ filp_open(dif->path, O_RDONLY | O_LARGEFILE, 0) :
+ fs_bdev_file_open_by_path(dif->path,
+ BLK_OPEN_READ, sb->s_type, sb);
+ if (IS_ERR(file)) {
+ if (file == ERR_PTR(-ENOTBLK))
+ return -EINVAL;
+ return PTR_ERR(file);
+ }
+
+ if (!erofs_is_fileio_mode(sbi)) {
+ dif->dax_dev = fs_dax_get_by_bdev(file_bdev(file),
+ &dif->dax_part_off, NULL, NULL);
+ } else if (!S_ISREG(file_inode(file)->i_mode)) {
+ fput(file);
+ return -EINVAL;
+ }
+ if (!dif->dax_dev && test_opt(&sbi->opt, DAX_ALWAYS)) {
+ erofs_info(sb, "DAX unsupported by %s. Turning off DAX.",
+ dif->path);
+ clear_opt(&sbi->opt, DAX_ALWAYS);
+ }
+ dif->file = file;
+ }
+
+ _48bit = erofs_sb_has_48bit(sbi);
+ dif->blocks = le32_to_cpu(dis->blocks_lo) |
+ (_48bit ? (u64)le16_to_cpu(dis->blocks_hi) << 32 : 0);
+ dif->uniaddr = le32_to_cpu(dis->uniaddr_lo) |
+ (_48bit ? (u64)le16_to_cpu(dis->uniaddr_hi) << 32 : 0);
+ sbi->total_blocks += dif->blocks;
+ *pos += EROFS_DEVT_SLOT_SIZE;
+ return 0;
+}
+
+static int erofs_scan_devices(struct super_block *sb,
+ struct erofs_super_block *dsb)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ unsigned int ondisk_extradevs;
+ erofs_off_t pos;
+ struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+ struct erofs_device_info *dif;
+ int id, err = 0;
+
+ sbi->total_blocks = sbi->dif0.blocks;
+ if (!erofs_sb_has_device_table(sbi))
+ ondisk_extradevs = 0;
+ else
+ ondisk_extradevs = le16_to_cpu(dsb->extra_devices);
+
+ if (sbi->devs->extra_devices &&
+ ondisk_extradevs != sbi->devs->extra_devices) {
+ erofs_err(sb, "extra devices don't match (ondisk %u, given %u)",
+ ondisk_extradevs, sbi->devs->extra_devices);
+ return -EINVAL;
+ }
+
+ if (test_opt(&sbi->opt, DAX_ALWAYS) && !sbi->dif0.dax_dev) {
+ erofs_info(sb, "DAX unsupported by block device. Turning off DAX.");
+ clear_opt(&sbi->opt, DAX_ALWAYS);
+ }
+ if (!ondisk_extradevs)
+ return 0;
+
+ if (!sbi->devs->extra_devices)
+ sbi->devs->flatdev = true;
+
+ sbi->device_id_mask = roundup_pow_of_two(ondisk_extradevs + 1) - 1;
+ pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE;
+ down_read(&sbi->devs->rwsem);
+ if (sbi->devs->extra_devices) {
+ idr_for_each_entry(&sbi->devs->tree, dif, id) {
+ err = erofs_init_device(&buf, sb, dif, &pos);
+ if (err)
+ break;
+ }
+ } else {
+ for (id = 0; id < ondisk_extradevs; id++) {
+ dif = kzalloc_obj(*dif);
+ if (!dif) {
+ err = -ENOMEM;
+ break;
+ }
+
+ err = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL);
+ if (err < 0) {
+ kfree(dif);
+ break;
+ }
+ ++sbi->devs->extra_devices;
+
+ err = erofs_init_device(&buf, sb, dif, &pos);
+ if (err)
+ break;
+ }
+ }
+ up_read(&sbi->devs->rwsem);
+ erofs_put_metabuf(&buf);
+ return err;
+}
+
+static int erofs_read_superblock(struct super_block *sb)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+ struct erofs_super_block *dsb;
+ void *data;
+ int ret;
+
+ data = erofs_read_metabuf(&buf, sb, 0, false);
+ if (IS_ERR(data)) {
+ erofs_err(sb, "cannot read erofs superblock");
+ return PTR_ERR(data);
+ }
+
+ dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
+ ret = -EINVAL;
+ if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
+ erofs_err(sb, "cannot find valid erofs superblock");
+ goto out;
+ }
+
+ sbi->blkszbits = dsb->blkszbits;
+ if (sbi->blkszbits < 9 || sbi->blkszbits > PAGE_SHIFT) {
+ erofs_err(sb, "blkszbits %u isn't supported", sbi->blkszbits);
+ goto out;
+ }
+ if (dsb->dirblkbits) {
+ erofs_err(sb, "dirblkbits %u isn't supported", dsb->dirblkbits);
+ goto out;
+ }
+
+ sbi->feature_compat = le32_to_cpu(dsb->feature_compat);
+ if (erofs_sb_has_sb_chksum(sbi)) {
+ ret = erofs_superblock_csum_verify(sb, data);
+ if (ret)
+ goto out;
+ }
+
+ ret = -EINVAL;
+ sbi->feature_incompat = le32_to_cpu(dsb->feature_incompat);
+ if (sbi->feature_incompat & ~EROFS_ALL_FEATURE_INCOMPAT) {
+ erofs_err(sb, "unidentified incompatible feature %x, please upgrade kernel",
+ sbi->feature_incompat & ~EROFS_ALL_FEATURE_INCOMPAT);
+ goto out;
+ }
+
+ sbi->sb_size = 128 + dsb->sb_extslots * EROFS_SB_EXTSLOT_SIZE;
+ if (sbi->sb_size > PAGE_SIZE - EROFS_SUPER_OFFSET) {
+ erofs_err(sb, "invalid sb_extslots %u (more than a fs block)",
+ sbi->sb_size);
+ goto out;
+ }
+ sbi->dif0.blocks = le32_to_cpu(dsb->blocks_lo);
+ sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
+#ifdef CONFIG_EROFS_FS_XATTR
+ sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
+ sbi->xattr_prefix_start = le32_to_cpu(dsb->xattr_prefix_start);
+ sbi->xattr_prefix_count = dsb->xattr_prefix_count;
+ sbi->xattr_filter_reserved = dsb->xattr_filter_reserved;
+ if (erofs_sb_has_ishare_xattrs(sbi)) {
+ if (dsb->ishare_xattr_prefix_id >= sbi->xattr_prefix_count) {
+ erofs_err(sb, "invalid ishare xattr prefix id %u",
+ dsb->ishare_xattr_prefix_id);
+ ret = -EFSCORRUPTED;
+ goto out;
+ }
+ sbi->ishare_xattr_prefix_id = dsb->ishare_xattr_prefix_id;
+ }
+#endif
+ sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact));
+ if (erofs_sb_has_48bit(sbi) && dsb->rootnid_8b) {
+ sbi->root_nid = le64_to_cpu(dsb->rootnid_8b);
+ sbi->dif0.blocks = sbi->dif0.blocks |
+ ((u64)le16_to_cpu(dsb->rb.blocks_hi) << 32);
+ } else {
+ sbi->root_nid = le16_to_cpu(dsb->rb.rootnid_2b);
+ }
+ sbi->packed_nid = le64_to_cpu(dsb->packed_nid);
+ if (erofs_sb_has_metabox(sbi)) {
+ ret = -EFSCORRUPTED;
+ if (sbi->sb_size <= offsetof(struct erofs_super_block,
+ metabox_nid))
+ goto out;
+ sbi->metabox_nid = le64_to_cpu(dsb->metabox_nid);
+ if (sbi->metabox_nid & BIT_ULL(EROFS_DIRENT_NID_METABOX_BIT))
+ goto out; /* self-loop detection */
+ }
+ sbi->inos = le64_to_cpu(dsb->inos);
+
+ sbi->epoch = (s64)le64_to_cpu(dsb->epoch);
+ sbi->fixed_nsec = le32_to_cpu(dsb->fixed_nsec);
+ super_set_uuid(sb, (void *)dsb->uuid, sizeof(dsb->uuid));
+
+ if (dsb->volume_name[0]) {
+ sbi->volume_name = kstrndup(dsb->volume_name,
+ sizeof(dsb->volume_name), GFP_KERNEL);
+ if (!sbi->volume_name) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ }
+
+ if (IS_ENABLED(CONFIG_EROFS_FS_ZIP)) {
+ ret = z_erofs_parse_cfgs(sb, dsb);
+ if (ret < 0)
+ goto out;
+ } else if (dsb->u1.available_compr_algs ||
+ erofs_sb_has_lz4_0padding(sbi)) {
+ erofs_err(sb, "compression disabled, unable to mount compressed EROFS");
+ ret = -EOPNOTSUPP;
+ goto out;
+ }
+
+ ret = erofs_scan_devices(sb, dsb);
+
+ if (erofs_sb_has_48bit(sbi))
+ erofs_info(sb, "EXPERIMENTAL 48-bit layout support in use. Use at your own risk!");
+ if (erofs_sb_has_metabox(sbi))
+ erofs_info(sb, "EXPERIMENTAL metadata compression support in use. Use at your own risk!");
+out:
+ erofs_put_metabuf(&buf);
+ return ret;
+}
+
+static void erofs_default_options(struct erofs_sb_info *sbi)
+{
+#ifdef CONFIG_EROFS_FS_ZIP
+ sbi->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND;
+ sbi->sync_decompress = EROFS_SYNC_DECOMPRESS_AUTO;
+#endif
+ if (IS_ENABLED(CONFIG_EROFS_FS_XATTR))
+ set_opt(&sbi->opt, XATTR_USER);
+ if (IS_ENABLED(CONFIG_EROFS_FS_POSIX_ACL))
+ set_opt(&sbi->opt, POSIX_ACL);
+}
+
+enum {
+ Opt_user_xattr, Opt_acl, Opt_cache_strategy, Opt_dax, Opt_dax_enum,
+ Opt_device, Opt_domain_id, Opt_directio, Opt_fsoffset, Opt_inode_share,
+ Opt_source,
+};
+
+static const struct constant_table erofs_param_cache_strategy[] = {
+ {"disabled", EROFS_ZIP_CACHE_DISABLED},
+ {"readahead", EROFS_ZIP_CACHE_READAHEAD},
+ {"readaround", EROFS_ZIP_CACHE_READAROUND},
+ {}
+};
+
+static const struct constant_table erofs_dax_param_enums[] = {
+ {"always", EROFS_MOUNT_DAX_ALWAYS},
+ {"never", EROFS_MOUNT_DAX_NEVER},
+ {}
+};
+
+static const struct fs_parameter_spec erofs_fs_parameters[] = {
+ fsparam_flag_no("user_xattr", Opt_user_xattr),
+ fsparam_flag_no("acl", Opt_acl),
+ fsparam_enum("cache_strategy", Opt_cache_strategy,
+ erofs_param_cache_strategy),
+ fsparam_flag("dax", Opt_dax),
+ fsparam_enum("dax", Opt_dax_enum, erofs_dax_param_enums),
+ fsparam_string("device", Opt_device),
+ fsparam_string("domain_id", Opt_domain_id),
+ fsparam_flag_no("directio", Opt_directio),
+ fsparam_u64("fsoffset", Opt_fsoffset),
+ fsparam_flag("inode_share", Opt_inode_share),
+ fsparam_file_or_string("source", Opt_source),
+ {}
+};
+
+static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode)
+{
+ if (IS_ENABLED(CONFIG_FS_DAX)) {
+ struct erofs_sb_info *sbi = fc->s_fs_info;
+
+ if (mode == EROFS_MOUNT_DAX_ALWAYS) {
+ set_opt(&sbi->opt, DAX_ALWAYS);
+ clear_opt(&sbi->opt, DAX_NEVER);
+ return true;
+ } else if (mode == EROFS_MOUNT_DAX_NEVER) {
+ set_opt(&sbi->opt, DAX_NEVER);
+ clear_opt(&sbi->opt, DAX_ALWAYS);
+ return true;
+ }
+ DBG_BUGON(1);
+ return false;
+ }
+ errorfc(fc, "dax options not supported");
+ return false;
+}
+
+static int erofs_fc_parse_source(struct fs_context *fc,
+ struct fs_parameter *param)
+{
+ struct erofs_sb_info *sbi = fc->s_fs_info;
+
+ if (fc->source || sbi->dif0.file)
+ return invalf(fc, "Multiple sources");
+
+ switch (param->type) {
+ case fs_value_is_string:
+ fc->source = param->string;
+ param->string = NULL;
+ return 0;
+ case fs_value_is_file: {
+ char *buf __free(kfree) = kmalloc(PATH_MAX, GFP_KERNEL);
+ char *p;
+
+ if (!buf)
+ return -ENOMEM;
+ p = file_path(param->file, buf, PATH_MAX);
+ if (IS_ERR(p))
+ return PTR_ERR(p);
+ fc->source = kstrdup(p, GFP_KERNEL);
+ if (!fc->source)
+ return -ENOMEM;
+ sbi->dif0.file = no_free_ptr(param->file);
+ return 0;
+ }
+ default:
+ WARN_ON_ONCE(true);
+ return -EINVAL;
+ }
+}
+
+static int erofs_fc_parse_param(struct fs_context *fc,
+ struct fs_parameter *param)
+{
+ struct erofs_sb_info *sbi = fc->s_fs_info;
+ struct fs_parse_result result;
+ struct erofs_device_info *dif;
+ int opt, ret;
+
+ opt = fs_parse(fc, erofs_fs_parameters, param, &result);
+ if (opt < 0)
+ return opt;
+
+ switch (opt) {
+ case Opt_user_xattr:
+ if (!IS_ENABLED(CONFIG_EROFS_FS_XATTR))
+ errorfc(fc, "{,no}user_xattr options not supported");
+ else if (result.boolean)
+ set_opt(&sbi->opt, XATTR_USER);
+ else
+ clear_opt(&sbi->opt, XATTR_USER);
+ break;
+ case Opt_acl:
+ if (!IS_ENABLED(CONFIG_EROFS_FS_POSIX_ACL))
+ errorfc(fc, "{,no}acl options not supported");
+ else if (result.boolean)
+ set_opt(&sbi->opt, POSIX_ACL);
+ else
+ clear_opt(&sbi->opt, POSIX_ACL);
+ break;
+ case Opt_cache_strategy:
+ if (!IS_ENABLED(CONFIG_EROFS_FS_ZIP))
+ errorfc(fc, "compression not supported, cache_strategy ignored");
+ else
+ sbi->opt.cache_strategy = result.uint_32;
+ break;
+ case Opt_dax:
+ if (!erofs_fc_set_dax_mode(fc, EROFS_MOUNT_DAX_ALWAYS))
+ return -EINVAL;
+ break;
+ case Opt_dax_enum:
+ if (!erofs_fc_set_dax_mode(fc, result.uint_32))
+ return -EINVAL;
+ break;
+ case Opt_device:
+ dif = kzalloc_obj(*dif);
+ if (!dif)
+ return -ENOMEM;
+ dif->path = kstrdup(param->string, GFP_KERNEL);
+ if (!dif->path) {
+ kfree(dif);
+ return -ENOMEM;
+ }
+ down_write(&sbi->devs->rwsem);
+ ret = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL);
+ up_write(&sbi->devs->rwsem);
+ if (ret < 0) {
+ kfree(dif->path);
+ kfree(dif);
+ return ret;
+ }
+ ++sbi->devs->extra_devices;
+ break;
+ case Opt_domain_id:
+ if (!IS_ENABLED(CONFIG_EROFS_FS_PAGE_CACHE_SHARE)) {
+ errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name);
+ } else {
+ kfree_sensitive(sbi->domain_id);
+ sbi->domain_id = no_free_ptr(param->string);
+ }
+ break;
+ case Opt_directio:
+ if (!IS_ENABLED(CONFIG_EROFS_FS_BACKED_BY_FILE))
+ errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name);
+ else if (result.boolean)
+ set_opt(&sbi->opt, DIRECT_IO);
+ else
+ clear_opt(&sbi->opt, DIRECT_IO);
+ break;
+ case Opt_fsoffset:
+ sbi->dif0.fsoff = result.uint_64;
+ break;
+ case Opt_inode_share:
+ if (!IS_ENABLED(CONFIG_EROFS_FS_PAGE_CACHE_SHARE))
+ errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name);
+ else
+ set_opt(&sbi->opt, INODE_SHARE);
+ break;
+ case Opt_source:
+ return erofs_fc_parse_source(fc, param);
+ }
+ return 0;
+}
+
+static int erofs_encode_fh(struct inode *inode, u32 *fh, int *max_len,
+ struct inode *parent)
+{
+ erofs_nid_t nid = EROFS_I(inode)->nid;
+ int len = parent ? 6 : 3;
+
+ if (*max_len < len) {
+ *max_len = len;
+ return FILEID_INVALID;
+ }
+
+ fh[0] = (u32)(nid >> 32);
+ fh[1] = (u32)(nid & 0xffffffff);
+ fh[2] = inode->i_generation;
+
+ if (parent) {
+ nid = EROFS_I(parent)->nid;
+
+ fh[3] = (u32)(nid >> 32);
+ fh[4] = (u32)(nid & 0xffffffff);
+ fh[5] = parent->i_generation;
+ }
+
+ *max_len = len;
+ return parent ? FILEID_INO64_GEN_PARENT : FILEID_INO64_GEN;
+}
+
+static struct dentry *erofs_fh_to_dentry(struct super_block *sb,
+ struct fid *fid, int fh_len, int fh_type)
+{
+ if ((fh_type != FILEID_INO64_GEN &&
+ fh_type != FILEID_INO64_GEN_PARENT) || fh_len < 3)
+ return NULL;
+
+ return d_obtain_alias(erofs_iget(sb,
+ ((u64)fid->raw[0] << 32) | fid->raw[1]));
+}
+
+static struct dentry *erofs_fh_to_parent(struct super_block *sb,
+ struct fid *fid, int fh_len, int fh_type)
+{
+ if (fh_type != FILEID_INO64_GEN_PARENT || fh_len < 6)
+ return NULL;
+
+ return d_obtain_alias(erofs_iget(sb,
+ ((u64)fid->raw[3] << 32) | fid->raw[4]));
+}
+
+static struct dentry *erofs_get_parent(struct dentry *child)
+{
+ erofs_nid_t nid;
+ unsigned int d_type;
+ int err;
+
+ err = erofs_namei(d_inode(child), &dotdot_name, &nid, &d_type);
+ if (err)
+ return ERR_PTR(err);
+ return d_obtain_alias(erofs_iget(child->d_sb, nid));
+}
+
+static const struct export_operations erofs_export_ops = {
+ .encode_fh = erofs_encode_fh,
+ .fh_to_dentry = erofs_fh_to_dentry,
+ .fh_to_parent = erofs_fh_to_parent,
+ .get_parent = erofs_get_parent,
+};
+
+int erofs_setup_managed_cache(struct super_block *sb)
+{
+ if (!EROFS_SB(sb)->managed_cache) {
+ struct inode *inode = new_inode(sb);
+
+ if (!inode)
+ return -ENOMEM;
+ set_nlink(inode, 1);
+ inode->i_size = OFFSET_MAX;
+ mapping_set_gfp_mask(inode->i_mapping, GFP_KERNEL);
+ EROFS_SB(sb)->managed_cache = inode;
+ }
+ return 0;
+}
+
+static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
+{
+ struct inode *inode;
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ int err;
+
+ sb->s_magic = EROFS_SUPER_MAGIC;
+ sb->s_flags |= SB_RDONLY | SB_NOATIME;
+ sb->s_maxbytes = MAX_LFS_FILESIZE;
+ sb->s_op = &erofs_sops;
+
+ if (!sbi->domain_id && test_opt(&sbi->opt, INODE_SHARE)) {
+ errorfc(fc, "domain_id is needed when inode_share is on");
+ return -EINVAL;
+ }
+ if (test_opt(&sbi->opt, DAX_ALWAYS) && test_opt(&sbi->opt, INODE_SHARE)) {
+ errorfc(fc, "FSDAX is not allowed when inode_share is on");
+ return -EINVAL;
+ }
+
+ sbi->blkszbits = PAGE_SHIFT;
+ if (erofs_is_fileio_mode(sbi)) {
+ /*
+ * (File-backed mounts) EROFS claims it's safe to nest other
+ * fs contexts (including its own) due to self-controlled RO
+ * accesses/contexts and no side-effect changes that need to
+ * context save & restore so it can reuse the current thread
+ * context.
+ * However, we still need to prevent kernel stack overflow due
+ * to filesystem nesting: just ensure that s_stack_depth is 0
+ * to disallow mounting EROFS on stacked filesystems.
+ * Note: s_stack_depth is not incremented here for now, since
+ * EROFS is the only fs supporting file-backed mounts for now.
+ * It MUST change if another fs plans to support them, which
+ * may also require adjusting FILESYSTEM_MAX_STACK_DEPTH.
+ */
+ inode = file_inode(sbi->dif0.file);
+ if ((inode->i_sb->s_op == &erofs_sops &&
+ !inode->i_sb->s_bdev) || inode->i_sb->s_stack_depth) {
+ erofs_err(sb, "file-backed mounts cannot be applied to stacked fses");
+ return -ENOTBLK;
+ }
+ sb->s_blocksize = PAGE_SIZE;
+ sb->s_blocksize_bits = PAGE_SHIFT;
+
+ err = super_setup_bdi(sb);
+ if (err)
+ return err;
+ err = erofs_setup_managed_cache(sb);
+ if (err)
+ return err;
+
+ snprintf(sb->s_id, sizeof(sb->s_id),
+ "%u:%u", MAJOR(sb->s_dev), MINOR(sb->s_dev));
+ } else {
+ if (!sb_set_blocksize(sb, PAGE_SIZE)) {
+ errorfc(fc, "failed to set initial blksize");
+ return -EINVAL;
+ }
+ sbi->dif0.dax_dev = fs_dax_get_by_bdev(sb->s_bdev,
+ &sbi->dif0.dax_part_off, NULL, NULL);
+ }
+
+ err = erofs_read_superblock(sb);
+ if (err)
+ return err;
+
+ if (sb->s_blocksize_bits != sbi->blkszbits) {
+ if (erofs_is_fileio_mode(sbi)) {
+ sb->s_blocksize = 1 << sbi->blkszbits;
+ sb->s_blocksize_bits = sbi->blkszbits;
+ } else if (!sb_set_blocksize(sb, 1 << sbi->blkszbits)) {
+ errorfc(fc, "failed to set erofs blksize");
+ return -EINVAL;
+ }
+ }
+ if (sbi->dif0.fsoff & (sb->s_blocksize - 1))
+ return invalfc(fc, "fsoffset %llu is not aligned to block size %lu",
+ sbi->dif0.fsoff, sb->s_blocksize);
+
+ if (test_opt(&sbi->opt, DAX_ALWAYS) && sbi->blkszbits != PAGE_SHIFT) {
+ erofs_info(sb, "unsupported blocksize for DAX");
+ clear_opt(&sbi->opt, DAX_ALWAYS);
+ }
+ if (test_opt(&sbi->opt, INODE_SHARE) && !erofs_sb_has_ishare_xattrs(sbi)) {
+ erofs_info(sb, "on-disk ishare xattrs not found. Turning off inode_share.");
+ clear_opt(&sbi->opt, INODE_SHARE);
+ }
+ if (test_opt(&sbi->opt, INODE_SHARE))
+ erofs_info(sb, "EXPERIMENTAL EROFS page cache share support in use. Use at your own risk!");
+
+ sb->s_time_gran = 1;
+ sb->s_xattr = erofs_xattr_handlers;
+ sb->s_export_op = &erofs_export_ops;
+
+ if (test_opt(&sbi->opt, POSIX_ACL))
+ sb->s_flags |= SB_POSIXACL;
+ else
+ sb->s_flags &= ~SB_POSIXACL;
+
+ err = z_erofs_init_super(sb);
+ if (err)
+ return err;
+
+ if (erofs_sb_has_fragments(sbi) && sbi->packed_nid) {
+ inode = erofs_iget(sb, sbi->packed_nid);
+ if (IS_ERR(inode))
+ return PTR_ERR(inode);
+ sbi->packed_inode = inode;
+ }
+ if (erofs_sb_has_metabox(sbi)) {
+ inode = erofs_iget(sb, sbi->metabox_nid);
+ if (IS_ERR(inode))
+ return PTR_ERR(inode);
+ sbi->metabox_inode = inode;
+ }
+
+ inode = erofs_iget(sb, sbi->root_nid);
+ if (IS_ERR(inode))
+ return PTR_ERR(inode);
+
+ if (!S_ISDIR(inode->i_mode)) {
+ erofs_err(sb, "rootino(nid %llu) is not a directory(i_mode %o)",
+ sbi->root_nid, inode->i_mode);
+ iput(inode);
+ return -EINVAL;
+ }
+ sb->s_root = d_make_root(inode);
+ if (!sb->s_root)
+ return -ENOMEM;
+
+ erofs_shrinker_register(sb);
+ err = erofs_xattr_prefixes_init(sb);
+ if (err)
+ return err;
+
+ super_set_sysfs_name_id(sb);
+ err = erofs_register_sysfs(sb);
+ if (err)
+ return err;
+
+ sbi->dir_ra_bytes = EROFS_DIR_RA_BYTES;
+ erofs_info(sb, "mounted with root inode @ nid %llu.", sbi->root_nid);
+ return 0;
+}
+
+static int erofs_fc_get_tree(struct fs_context *fc)
+{
+ struct erofs_sb_info *sbi = fc->s_fs_info;
+ int ret;
+
+ if (sbi->dif0.file) {
+ if (!IS_ENABLED(CONFIG_EROFS_FS_BACKED_BY_FILE)) {
+ errorfc(fc, "source fd option not supported");
+ return -EINVAL;
+ }
+ if (!S_ISREG(file_inode(sbi->dif0.file)->i_mode) ||
+ !sbi->dif0.file->f_mapping->a_ops->read_folio) {
+ errorfc(fc, "source is unsupported");
+ return -EINVAL;
+ }
+ return get_tree_nodev(fc, erofs_fc_fill_super);
+ }
+
+ ret = get_tree_bdev_flags(fc, erofs_fc_fill_super,
+ IS_ENABLED(CONFIG_EROFS_FS_BACKED_BY_FILE) ?
+ GET_TREE_BDEV_QUIET_LOOKUP : 0);
+ if (IS_ENABLED(CONFIG_EROFS_FS_BACKED_BY_FILE) && ret == -ENOTBLK) {
+ struct file *file;
+
+ if (!fc->source)
+ return invalf(fc, "No source specified");
+ file = filp_open(fc->source, O_RDONLY | O_LARGEFILE, 0);
+ if (IS_ERR(file))
+ return PTR_ERR(file);
+ sbi->dif0.file = file;
+
+ if (S_ISREG(file_inode(sbi->dif0.file)->i_mode) &&
+ sbi->dif0.file->f_mapping->a_ops->read_folio)
+ return get_tree_nodev(fc, erofs_fc_fill_super);
+ }
+ return ret;
+}
+
+static int erofs_fc_reconfigure(struct fs_context *fc)
+{
+ struct super_block *sb = fc->root->d_sb;
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ struct erofs_sb_info *new_sbi = fc->s_fs_info;
+
+ DBG_BUGON(!sb_rdonly(sb));
+
+ if (new_sbi->domain_id)
+ erofs_info(sb, "ignoring reconfiguration for domain_id.");
+
+ if (test_opt(&new_sbi->opt, POSIX_ACL))
+ fc->sb_flags |= SB_POSIXACL;
+ else
+ fc->sb_flags &= ~SB_POSIXACL;
+
+ sbi->opt = new_sbi->opt;
+
+ fc->sb_flags |= SB_RDONLY;
+ return 0;
+}
+
+static int erofs_release_device_info(int id, void *ptr, void *data)
+{
+ struct super_block *sb = data;
+ struct erofs_device_info *dif = ptr;
+
+ fs_put_dax(dif->dax_dev, NULL);
+ if (dif->file) {
+ if (S_ISBLK(file_inode(dif->file)->i_mode))
+ fs_bdev_file_release(dif->file, sb);
+ else
+ fput(dif->file);
+ }
+ kfree(dif->path);
+ kfree(dif);
+ return 0;
+}
+
+static void erofs_free_dev_context(struct erofs_dev_context *devs,
+ struct super_block *sb)
+{
+ if (!devs)
+ return;
+ idr_for_each(&devs->tree, &erofs_release_device_info, sb);
+ idr_destroy(&devs->tree);
+ kfree(devs);
+}
+
+static void erofs_sb_free(struct erofs_sb_info *sbi, struct super_block *sb)
+{
+ erofs_free_dev_context(sbi->devs, sb);
+ kfree_sensitive(sbi->domain_id);
+ if (sbi->dif0.file)
+ fput(sbi->dif0.file);
+ kfree(sbi->volume_name);
+ kfree(sbi);
+}
+
+static void erofs_fc_free(struct fs_context *fc)
+{
+ struct erofs_sb_info *sbi = fc->s_fs_info;
+
+ /*
+ * Freed here only if an error occurs before the sb is set up; at that
+ * point no block-backed device has been claimed (that happens in
+ * fill_super), so the NULL sb never reaches fs_bdev_file_release().
+ */
+ if (sbi)
+ erofs_sb_free(sbi, NULL);
+}
+
+static const struct fs_context_operations erofs_context_ops = {
+ .parse_param = erofs_fc_parse_param,
+ .get_tree = erofs_fc_get_tree,
+ .reconfigure = erofs_fc_reconfigure,
+ .free = erofs_fc_free,
+};
+
+static int erofs_init_fs_context(struct fs_context *fc)
+{
+ struct erofs_sb_info *sbi;
+
+ sbi = kzalloc_obj(*sbi);
+ if (!sbi)
+ return -ENOMEM;
+
+ sbi->devs = kzalloc_obj(struct erofs_dev_context);
+ if (!sbi->devs) {
+ kfree(sbi);
+ return -ENOMEM;
+ }
+ fc->s_fs_info = sbi;
+
+ idr_init(&sbi->devs->tree);
+ init_rwsem(&sbi->devs->rwsem);
+ erofs_default_options(sbi);
+ fc->ops = &erofs_context_ops;
+ return 0;
+}
+
+static void erofs_drop_internal_inodes(struct erofs_sb_info *sbi)
+{
+ iput(sbi->packed_inode);
+ sbi->packed_inode = NULL;
+ iput(sbi->metabox_inode);
+ sbi->metabox_inode = NULL;
+ iput(sbi->managed_cache);
+ sbi->managed_cache = NULL;
+}
+
+static void erofs_kill_sb(struct super_block *sb)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+
+ if (sbi->dif0.file)
+ kill_anon_super(sb);
+ else
+ kill_block_super(sb);
+ erofs_drop_internal_inodes(sbi);
+ fs_put_dax(sbi->dif0.dax_dev, NULL);
+ erofs_sb_free(sbi, sb);
+ sb->s_fs_info = NULL;
+}
+
+static void erofs_put_super(struct super_block *sb)
+{
+ struct erofs_sb_info *const sbi = EROFS_SB(sb);
+
+ erofs_unregister_sysfs(sb);
+ erofs_shrinker_unregister(sb);
+ erofs_xattr_prefixes_cleanup(sb);
+ erofs_drop_internal_inodes(sbi);
+ erofs_free_dev_context(sbi->devs, sb);
+ sbi->devs = NULL;
+}
+
+static struct file_system_type erofs_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "erofs",
+ .init_fs_context = erofs_init_fs_context,
+ .kill_sb = erofs_kill_sb,
+ .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
+};
+MODULE_ALIAS_FS("erofs");
+
+#ifdef CONFIG_EROFS_FS_PAGE_CACHE_SHARE
+static void erofs_free_anon_inode(struct inode *inode)
+{
+ struct erofs_inode *vi = EROFS_I(inode);
+
+ kfree(vi->fingerprint.opaque);
+ kmem_cache_free(erofs_inode_cachep, vi);
+}
+
+static const struct super_operations erofs_anon_sops = {
+ .alloc_inode = erofs_alloc_inode,
+ .drop_inode = inode_just_drop,
+ .free_inode = erofs_free_anon_inode,
+};
+
+static int erofs_anon_init_fs_context(struct fs_context *fc)
+{
+ struct pseudo_fs_context *ctx;
+
+ ctx = init_pseudo(fc, EROFS_SUPER_MAGIC);
+ if (!ctx)
+ return -ENOMEM;
+ ctx->ops = &erofs_anon_sops;
+ return 0;
+}
+
+struct file_system_type erofs_anon_fs_type = {
+ .name = "pseudo_erofs",
+ .init_fs_context = erofs_anon_init_fs_context,
+ .kill_sb = kill_anon_super,
+};
+#endif
+
+static int __init erofs_module_init(void)
+{
+ int err;
+
+ erofs_check_ondisk_layout_definitions();
+
+ erofs_inode_cachep = kmem_cache_create("erofs_inode",
+ sizeof(struct erofs_inode), 0,
+ SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT,
+ erofs_inode_init_once);
+ if (!erofs_inode_cachep)
+ return -ENOMEM;
+
+ err = erofs_init_shrinker();
+ if (err)
+ goto shrinker_err;
+
+ err = z_erofs_init_subsystem();
+ if (err)
+ goto zip_err;
+
+ err = erofs_init_sysfs();
+ if (err)
+ goto sysfs_err;
+
+ err = erofs_init_ishare();
+ if (err)
+ goto ishare_err;
+
+ err = register_filesystem(&erofs_fs_type);
+ if (err)
+ goto fs_err;
+
+ return 0;
+
+fs_err:
+ erofs_exit_ishare();
+ishare_err:
+ erofs_exit_sysfs();
+sysfs_err:
+ z_erofs_exit_subsystem();
+zip_err:
+ erofs_exit_shrinker();
+shrinker_err:
+ kmem_cache_destroy(erofs_inode_cachep);
+ return err;
+}
+
+static void __exit erofs_module_exit(void)
+{
+ unregister_filesystem(&erofs_fs_type);
+ erofs_exit_ishare();
+
+ /* ensure all delayed rcu free inodes & pclusters are flushed */
+ rcu_barrier();
+
+ erofs_exit_sysfs();
+ z_erofs_exit_subsystem();
+ erofs_exit_shrinker();
+ kmem_cache_destroy(erofs_inode_cachep);
+}
+
+static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+ struct super_block *sb = dentry->d_sb;
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+
+ buf->f_type = sb->s_magic;
+ buf->f_bsize = sb->s_blocksize;
+ buf->f_blocks = sbi->total_blocks;
+ buf->f_bfree = buf->f_bavail = 0;
+ buf->f_files = ULLONG_MAX;
+ buf->f_ffree = ULLONG_MAX - sbi->inos;
+ buf->f_namelen = EROFS_NAME_LEN;
+
+ if (uuid_is_null(&sb->s_uuid))
+ buf->f_fsid = u64_to_fsid(!sb->s_bdev ? 0 :
+ huge_encode_dev(sb->s_bdev->bd_dev));
+ else
+ buf->f_fsid = uuid_to_fsid(sb->s_uuid.b);
+ return 0;
+}
+
+static int erofs_show_options(struct seq_file *seq, struct dentry *root)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(root->d_sb);
+ struct erofs_mount_opts *opt = &sbi->opt;
+
+ if (IS_ENABLED(CONFIG_EROFS_FS_XATTR))
+ seq_puts(seq, test_opt(opt, XATTR_USER) ?
+ ",user_xattr" : ",nouser_xattr");
+ if (IS_ENABLED(CONFIG_EROFS_FS_POSIX_ACL))
+ seq_puts(seq, test_opt(opt, POSIX_ACL) ? ",acl" : ",noacl");
+ if (IS_ENABLED(CONFIG_EROFS_FS_ZIP) && sbi->available_compr_algs)
+ seq_printf(seq, ",cache_strategy=%s",
+ erofs_param_cache_strategy[opt->cache_strategy].name);
+ if (test_opt(opt, DAX_ALWAYS))
+ seq_puts(seq, ",dax=always");
+ if (test_opt(opt, DAX_NEVER))
+ seq_puts(seq, ",dax=never");
+ if (erofs_is_fileio_mode(sbi) && test_opt(opt, DIRECT_IO))
+ seq_puts(seq, ",directio");
+ if (sbi->dif0.fsoff)
+ seq_printf(seq, ",fsoffset=%llu", sbi->dif0.fsoff);
+ if (test_opt(opt, INODE_SHARE))
+ seq_puts(seq, ",inode_share");
+ return 0;
+}
+
+static void erofs_evict_inode(struct inode *inode)
+{
+ if (IS_DAX(inode))
+ dax_break_layout_final(inode);
+ erofs_ishare_free_inode(inode);
+ truncate_inode_pages_final(&inode->i_data);
+ clear_inode(inode);
+}
+
+const struct super_operations erofs_sops = {
+ .put_super = erofs_put_super,
+ .alloc_inode = erofs_alloc_inode,
+ .free_inode = erofs_free_inode,
+ .evict_inode = erofs_evict_inode,
+ .statfs = erofs_statfs,
+ .show_options = erofs_show_options,
+};
+
+module_init(erofs_module_init);
+module_exit(erofs_module_exit);
+
+MODULE_DESCRIPTION("Enhanced ROM File System");
+MODULE_AUTHOR("Gao Xiang, Chao Yu, Miao Xie, CONSUMER BG, HUAWEI Inc.");
+MODULE_LICENSE("GPL");
diff --git a/fs/erofs/sysfs.c b/fs/erofs/sysfs.c
new file mode 100644
index 000000000..6734483a4
--- /dev/null
+++ b/fs/erofs/sysfs.c
@@ -0,0 +1,302 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C), 2008-2021, OPPO Mobile Comm Corp., Ltd.
+ * https://www.oppo.com/
+ */
+#include <linux/sysfs.h>
+#include <linux/kobject.h>
+
+#include "internal.h"
+#include "compress.h"
+
+enum {
+ attr_feature,
+ attr_drop_caches,
+ attr_pointer_ui,
+ attr_pointer_bool,
+ attr_accel,
+};
+
+enum {
+ struct_erofs_sb_info,
+ struct_erofs_mount_opts,
+};
+
+struct erofs_attr {
+ struct attribute attr;
+ short attr_id;
+ int struct_type, offset;
+};
+
+#define EROFS_ATTR(_name, _mode, _id) \
+static struct erofs_attr erofs_attr_##_name = { \
+ .attr = {.name = __stringify(_name), .mode = _mode }, \
+ .attr_id = attr_##_id, \
+}
+#define EROFS_ATTR_FUNC(_name, _mode) EROFS_ATTR(_name, _mode, _name)
+#define EROFS_ATTR_FEATURE(_name) EROFS_ATTR(_name, 0444, feature)
+
+#define EROFS_ATTR_OFFSET(_name, _mode, _id, _struct) \
+static struct erofs_attr erofs_attr_##_name = { \
+ .attr = {.name = __stringify(_name), .mode = _mode }, \
+ .attr_id = attr_##_id, \
+ .struct_type = struct_##_struct, \
+ .offset = offsetof(struct _struct, _name),\
+}
+
+#define EROFS_ATTR_RW(_name, _id, _struct) \
+ EROFS_ATTR_OFFSET(_name, 0644, _id, _struct)
+
+#define EROFS_RO_ATTR(_name, _id, _struct) \
+ EROFS_ATTR_OFFSET(_name, 0444, _id, _struct)
+
+#define EROFS_ATTR_RW_UI(_name, _struct) \
+ EROFS_ATTR_RW(_name, pointer_ui, _struct)
+
+#define EROFS_ATTR_RW_BOOL(_name, _struct) \
+ EROFS_ATTR_RW(_name, pointer_bool, _struct)
+
+#define ATTR_LIST(name) (&erofs_attr_##name.attr)
+
+#ifdef CONFIG_EROFS_FS_ZIP
+EROFS_ATTR_RW_UI(sync_decompress, erofs_sb_info);
+EROFS_ATTR_FUNC(drop_caches, 0200);
+#endif
+#ifdef CONFIG_EROFS_FS_ZIP_ACCEL
+EROFS_ATTR_FUNC(accel, 0644);
+#endif
+EROFS_ATTR_RW_UI(dir_ra_bytes, erofs_sb_info);
+
+static struct attribute *erofs_sb_attrs[] = {
+#ifdef CONFIG_EROFS_FS_ZIP
+ ATTR_LIST(sync_decompress),
+ ATTR_LIST(drop_caches),
+#endif
+ ATTR_LIST(dir_ra_bytes),
+ NULL,
+};
+ATTRIBUTE_GROUPS(erofs_sb);
+
+static struct attribute *erofs_attrs[] = {
+#ifdef CONFIG_EROFS_FS_ZIP_ACCEL
+ ATTR_LIST(accel),
+#endif
+ NULL,
+};
+ATTRIBUTE_GROUPS(erofs);
+
+/* Features this copy of erofs supports */
+EROFS_ATTR_FEATURE(compr_cfgs);
+EROFS_ATTR_FEATURE(big_pcluster);
+EROFS_ATTR_FEATURE(chunked_file);
+EROFS_ATTR_FEATURE(device_table);
+EROFS_ATTR_FEATURE(compr_head2);
+EROFS_ATTR_FEATURE(sb_chksum);
+EROFS_ATTR_FEATURE(ztailpacking);
+EROFS_ATTR_FEATURE(fragments);
+EROFS_ATTR_FEATURE(dedupe);
+EROFS_ATTR_FEATURE(48bit);
+EROFS_ATTR_FEATURE(metabox);
+
+static struct attribute *erofs_feat_attrs[] = {
+ ATTR_LIST(compr_cfgs),
+ ATTR_LIST(big_pcluster),
+ ATTR_LIST(chunked_file),
+ ATTR_LIST(device_table),
+ ATTR_LIST(compr_head2),
+ ATTR_LIST(sb_chksum),
+ ATTR_LIST(ztailpacking),
+ ATTR_LIST(fragments),
+ ATTR_LIST(dedupe),
+ ATTR_LIST(48bit),
+ ATTR_LIST(metabox),
+ NULL,
+};
+ATTRIBUTE_GROUPS(erofs_feat);
+
+static unsigned char *__struct_ptr(struct erofs_sb_info *sbi,
+ int struct_type, int offset)
+{
+ if (struct_type == struct_erofs_sb_info)
+ return (unsigned char *)sbi + offset;
+ if (struct_type == struct_erofs_mount_opts)
+ return (unsigned char *)&sbi->opt + offset;
+ return NULL;
+}
+
+static ssize_t erofs_attr_show(struct kobject *kobj,
+ struct attribute *attr, char *buf)
+{
+ struct erofs_sb_info *sbi = container_of(kobj, struct erofs_sb_info,
+ s_kobj);
+ struct erofs_attr *a = container_of(attr, struct erofs_attr, attr);
+ unsigned char *ptr = __struct_ptr(sbi, a->struct_type, a->offset);
+
+ switch (a->attr_id) {
+ case attr_feature:
+ return sysfs_emit(buf, "supported\n");
+ case attr_pointer_ui:
+ if (!ptr)
+ return 0;
+ return sysfs_emit(buf, "%u\n", *(unsigned int *)ptr);
+ case attr_pointer_bool:
+ if (!ptr)
+ return 0;
+ return sysfs_emit(buf, "%d\n", *(bool *)ptr);
+ case attr_accel:
+ return z_erofs_crypto_show_engines(buf, PAGE_SIZE, '\n');
+ }
+ return 0;
+}
+
+static ssize_t erofs_attr_store(struct kobject *kobj, struct attribute *attr,
+ const char *buf, size_t len)
+{
+ struct erofs_sb_info *sbi = container_of(kobj, struct erofs_sb_info,
+ s_kobj);
+ struct erofs_attr *a = container_of(attr, struct erofs_attr, attr);
+ unsigned char *ptr = __struct_ptr(sbi, a->struct_type, a->offset);
+ unsigned long t;
+ int ret;
+
+ switch (a->attr_id) {
+ case attr_pointer_ui:
+ if (!ptr)
+ return 0;
+ ret = kstrtoul(skip_spaces(buf), 0, &t);
+ if (ret)
+ return ret;
+ if (t != (unsigned int)t)
+ return -ERANGE;
+ if (IS_ENABLED(CONFIG_EROFS_FS_ZIP) &&
+ !strcmp(a->attr.name, "sync_decompress") &&
+ (t > EROFS_SYNC_DECOMPRESS_FORCE_OFF))
+ return -EINVAL;
+ *(unsigned int *)ptr = t;
+ return len;
+ case attr_pointer_bool:
+ if (!ptr)
+ return 0;
+ ret = kstrtoul(skip_spaces(buf), 0, &t);
+ if (ret)
+ return ret;
+ if (t != 0 && t != 1)
+ return -EINVAL;
+ *(bool *)ptr = !!t;
+ return len;
+#ifdef CONFIG_EROFS_FS_ZIP
+ case attr_drop_caches:
+ ret = kstrtoul(skip_spaces(buf), 0, &t);
+ if (ret)
+ return ret;
+ if (t < 1 || t > 3)
+ return -EINVAL;
+
+ if (t & 2)
+ z_erofs_shrink_scan(sbi, ~0UL);
+ if (t & 1)
+ invalidate_mapping_pages(MNGD_MAPPING(sbi), 0, -1);
+ return len;
+#endif
+#ifdef CONFIG_EROFS_FS_ZIP_ACCEL
+ case attr_accel:
+ buf = skip_spaces(buf);
+ z_erofs_crypto_disable_all_engines();
+ while (*buf) {
+ t = strcspn(buf, "\n");
+ ret = z_erofs_crypto_enable_engine(buf, t);
+ if (ret < 0)
+ return ret;
+ buf += buf[t] != '\0' ? t + 1 : t;
+ }
+ return len;
+#endif
+ }
+ return 0;
+}
+
+static void erofs_sb_release(struct kobject *kobj)
+{
+ struct erofs_sb_info *sbi = container_of(kobj, struct erofs_sb_info,
+ s_kobj);
+ complete(&sbi->s_kobj_unregister);
+}
+
+static const struct sysfs_ops erofs_attr_ops = {
+ .show = erofs_attr_show,
+ .store = erofs_attr_store,
+};
+
+static const struct kobj_type erofs_sb_ktype = {
+ .default_groups = erofs_sb_groups,
+ .sysfs_ops = &erofs_attr_ops,
+ .release = erofs_sb_release,
+};
+
+static const struct kobj_type erofs_ktype = {
+ .default_groups = erofs_groups,
+ .sysfs_ops = &erofs_attr_ops,
+};
+
+static struct kset erofs_root = {
+ .kobj = {.ktype = &erofs_ktype},
+};
+
+static const struct kobj_type erofs_feat_ktype = {
+ .default_groups = erofs_feat_groups,
+ .sysfs_ops = &erofs_attr_ops,
+};
+
+static struct kobject erofs_feat = {
+ .kset = &erofs_root,
+};
+
+int erofs_register_sysfs(struct super_block *sb)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ int err;
+
+ sbi->s_kobj.kset = &erofs_root;
+ init_completion(&sbi->s_kobj_unregister);
+ err = kobject_init_and_add(&sbi->s_kobj, &erofs_sb_ktype, NULL, "%s",
+ sb->s_sysfs_name);
+ if (err) {
+ kobject_put(&sbi->s_kobj);
+ wait_for_completion(&sbi->s_kobj_unregister);
+ }
+ return err;
+}
+
+void erofs_unregister_sysfs(struct super_block *sb)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+
+ if (sbi->s_kobj.state_in_sysfs) {
+ kobject_del(&sbi->s_kobj);
+ kobject_put(&sbi->s_kobj);
+ wait_for_completion(&sbi->s_kobj_unregister);
+ }
+}
+
+void erofs_exit_sysfs(void)
+{
+ kobject_put(&erofs_feat);
+ kset_unregister(&erofs_root);
+}
+
+int __init erofs_init_sysfs(void)
+{
+ int ret;
+
+ kobject_set_name(&erofs_root.kobj, "erofs");
+ erofs_root.kobj.parent = fs_kobj;
+ ret = kset_register(&erofs_root);
+ if (!ret) {
+ ret = kobject_init_and_add(&erofs_feat, &erofs_feat_ktype,
+ NULL, "features");
+ if (!ret)
+ return 0;
+ erofs_exit_sysfs();
+ }
+ return ret;
+}
diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
new file mode 100644
index 000000000..df7ea0195
--- /dev/null
+++ b/fs/erofs/xattr.c
@@ -0,0 +1,649 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ * https://www.huawei.com/
+ * Copyright (C) 2021-2022, Alibaba Cloud
+ */
+#include <linux/security.h>
+#include <linux/xxhash.h>
+#include "xattr.h"
+
+struct erofs_xattr_iter {
+ struct super_block *sb;
+ struct erofs_buf buf;
+ erofs_off_t pos;
+ void *kaddr;
+
+ char *buffer;
+ int buffer_size, buffer_ofs;
+
+ /* getxattr */
+ int index, infix_len;
+ struct qstr name;
+
+ /* listxattr */
+ struct dentry *dentry;
+};
+
+static const char *erofs_xattr_prefix(unsigned int idx, struct dentry *dentry);
+
+static int erofs_init_inode_xattrs(struct inode *inode)
+{
+ struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+ struct erofs_inode *vi = EROFS_I(inode);
+ struct super_block *sb = inode->i_sb;
+ const struct erofs_xattr_ibody_header *ih;
+ __le32 *xattr_id;
+ erofs_off_t pos;
+ unsigned int i;
+ int ret = 0;
+
+ if (!vi->xattr_isize)
+ return -ENODATA;
+
+ /* the most case is that xattrs of this inode are initialized. */
+ if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags)) {
+ /*
+ * paired with smp_mb() at the end of the function to ensure
+ * fields will only be observed after the bit is set.
+ */
+ smp_mb();
+ return 0;
+ }
+ if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_XATTR_BIT, TASK_KILLABLE))
+ return -ERESTARTSYS;
+
+ /* someone has initialized xattrs for us? */
+ if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags))
+ goto out_unlock;
+
+ /*
+ * bypass all xattr operations if ->xattr_isize is not greater than
+ * sizeof(struct erofs_xattr_ibody_header), in detail:
+ * 1) it is not enough to contain erofs_xattr_ibody_header then
+ * ->xattr_isize should be 0 (it means no xattr);
+ * 2) it is just to contain erofs_xattr_ibody_header, which is on-disk
+ * undefined right now (maybe use later with some new sb feature).
+ */
+ if (vi->xattr_isize == sizeof(struct erofs_xattr_ibody_header)) {
+ erofs_err(sb, "xattr_isize %d of nid %llu is not supported yet",
+ vi->xattr_isize, vi->nid);
+ ret = -EOPNOTSUPP;
+ goto out_unlock;
+ } else if (vi->xattr_isize < sizeof(struct erofs_xattr_ibody_header)) {
+ erofs_err(sb, "bogus xattr ibody @ nid %llu", vi->nid);
+ DBG_BUGON(1);
+ ret = -EFSCORRUPTED;
+ goto out_unlock;
+ }
+
+ pos = erofs_iloc(inode) + vi->inode_isize;
+ ih = erofs_read_metabuf(&buf, sb, pos, erofs_inode_in_metabox(inode));
+ if (IS_ERR(ih)) {
+ ret = PTR_ERR(ih);
+ goto out_unlock;
+ }
+ vi->xattr_name_filter = le32_to_cpu(ih->h_name_filter);
+ vi->xattr_shared_count = ih->h_shared_count;
+ if ((u32)vi->xattr_shared_count * sizeof(__le32) >
+ vi->xattr_isize - sizeof(struct erofs_xattr_ibody_header)) {
+ erofs_err(sb, "invalid h_shared_count %u @ nid %llu",
+ vi->xattr_shared_count, vi->nid);
+ ret = -EFSCORRUPTED;
+ goto out_unlock;
+ }
+ vi->xattr_shared_xattrs = kmalloc_objs(uint, vi->xattr_shared_count);
+ if (!vi->xattr_shared_xattrs) {
+ ret = -ENOMEM;
+ goto out_unlock;
+ }
+
+ /* skip the ibody header and read the shared xattr array */
+ pos += sizeof(struct erofs_xattr_ibody_header);
+ for (i = 0; i < vi->xattr_shared_count; ++i) {
+ xattr_id = erofs_bread(&buf, pos + i * sizeof(__le32), true);
+ if (IS_ERR(xattr_id)) {
+ kfree(vi->xattr_shared_xattrs);
+ vi->xattr_shared_xattrs = NULL;
+ ret = PTR_ERR(xattr_id);
+ goto out_unlock;
+ }
+ vi->xattr_shared_xattrs[i] = le32_to_cpu(*xattr_id);
+ }
+
+ /* paired with smp_mb() at the beginning of the function. */
+ smp_mb();
+ set_bit(EROFS_I_EA_INITED_BIT, &vi->flags);
+out_unlock:
+ erofs_put_metabuf(&buf);
+ clear_and_wake_up_bit(EROFS_I_BL_XATTR_BIT, &vi->flags);
+ return ret;
+}
+
+static int erofs_xattr_copy_to_buffer(struct erofs_xattr_iter *it,
+ unsigned int len)
+{
+ unsigned int slice, processed;
+ struct super_block *sb = it->sb;
+
+ for (processed = 0; processed < len; processed += slice) {
+ it->kaddr = erofs_bread(&it->buf, it->pos, true);
+ if (IS_ERR(it->kaddr))
+ return PTR_ERR(it->kaddr);
+
+ slice = min_t(unsigned int, sb->s_blocksize -
+ erofs_blkoff(sb, it->pos), len - processed);
+ memcpy(it->buffer + it->buffer_ofs, it->kaddr, slice);
+ it->buffer_ofs += slice;
+ it->pos += slice;
+ }
+ return 0;
+}
+
+static int erofs_listxattr_foreach(struct erofs_xattr_iter *it)
+{
+ struct erofs_xattr_entry entry;
+ unsigned int base_index, name_total, prefix_len, infix_len = 0;
+ const char *prefix, *infix = NULL;
+ int err;
+
+ /* 1. handle xattr entry */
+ entry = *(struct erofs_xattr_entry *)it->kaddr;
+ it->pos += sizeof(struct erofs_xattr_entry);
+
+ base_index = entry.e_name_index;
+ if (entry.e_name_index & EROFS_XATTR_LONG_PREFIX) {
+ struct erofs_sb_info *sbi = EROFS_SB(it->sb);
+ struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes +
+ (entry.e_name_index & EROFS_XATTR_LONG_PREFIX_MASK);
+
+ if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count)
+ return 0;
+ infix = pf->prefix->infix;
+ infix_len = pf->infix_len;
+ base_index = pf->prefix->base_index;
+ }
+
+ prefix = erofs_xattr_prefix(base_index, it->dentry);
+ if (!prefix)
+ return 0;
+ prefix_len = strlen(prefix);
+ name_total = prefix_len + infix_len + entry.e_name_len + 1;
+
+ if (!it->buffer) {
+ it->buffer_ofs += name_total;
+ return 0;
+ }
+
+ if (it->buffer_ofs + name_total > it->buffer_size)
+ return -ERANGE;
+
+ memcpy(it->buffer + it->buffer_ofs, prefix, prefix_len);
+ memcpy(it->buffer + it->buffer_ofs + prefix_len, infix, infix_len);
+ it->buffer_ofs += prefix_len + infix_len;
+
+ /* 2. handle xattr name */
+ err = erofs_xattr_copy_to_buffer(it, entry.e_name_len);
+ if (err)
+ return err;
+
+ it->buffer[it->buffer_ofs++] = '\0';
+ return 0;
+}
+
+static int erofs_getxattr_foreach(struct erofs_xattr_iter *it)
+{
+ struct super_block *sb = it->sb;
+ struct erofs_xattr_entry entry;
+ unsigned int slice, processed, value_sz;
+
+ /* 1. handle xattr entry */
+ entry = *(struct erofs_xattr_entry *)it->kaddr;
+ it->pos += sizeof(struct erofs_xattr_entry);
+ value_sz = le16_to_cpu(entry.e_value_size);
+
+ /* should also match the infix for long name prefixes */
+ if (entry.e_name_index & EROFS_XATTR_LONG_PREFIX) {
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes +
+ (entry.e_name_index & EROFS_XATTR_LONG_PREFIX_MASK);
+
+ if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count)
+ return -ENODATA;
+
+ if (it->index != pf->prefix->base_index ||
+ it->name.len != entry.e_name_len + pf->infix_len)
+ return -ENODATA;
+
+ if (memcmp(it->name.name, pf->prefix->infix, pf->infix_len))
+ return -ENODATA;
+
+ it->infix_len = pf->infix_len;
+ } else {
+ if (it->index != entry.e_name_index ||
+ it->name.len != entry.e_name_len)
+ return -ENODATA;
+
+ it->infix_len = 0;
+ }
+
+ /* 2. handle xattr name */
+ for (processed = 0; processed < entry.e_name_len; processed += slice) {
+ it->kaddr = erofs_bread(&it->buf, it->pos, true);
+ if (IS_ERR(it->kaddr))
+ return PTR_ERR(it->kaddr);
+
+ slice = min_t(unsigned int,
+ sb->s_blocksize - erofs_blkoff(sb, it->pos),
+ entry.e_name_len - processed);
+ if (memcmp(it->name.name + it->infix_len + processed,
+ it->kaddr, slice))
+ return -ENODATA;
+ it->pos += slice;
+ }
+
+ /* 3. handle xattr value */
+ if (!it->buffer) {
+ it->buffer_ofs = value_sz;
+ return 0;
+ }
+
+ if (it->buffer_size < value_sz)
+ return -ERANGE;
+
+ return erofs_xattr_copy_to_buffer(it, value_sz);
+}
+
+static int erofs_xattr_iter_inline(struct erofs_xattr_iter *it,
+ struct inode *inode, bool getxattr)
+{
+ struct erofs_inode *const vi = EROFS_I(inode);
+ unsigned int xattr_header_sz, remaining, entry_sz;
+ erofs_off_t next_pos;
+ int ret;
+
+ xattr_header_sz = sizeof(struct erofs_xattr_ibody_header) +
+ sizeof(u32) * vi->xattr_shared_count;
+ if (xattr_header_sz >= vi->xattr_isize) {
+ DBG_BUGON(xattr_header_sz > vi->xattr_isize);
+ return -ENODATA;
+ }
+
+ ret = erofs_init_metabuf(&it->buf, it->sb, erofs_inode_in_metabox(inode));
+ if (ret)
+ return ret;
+ remaining = vi->xattr_isize - xattr_header_sz;
+ it->pos = erofs_iloc(inode) + vi->inode_isize + xattr_header_sz;
+
+ while (remaining) {
+ it->kaddr = erofs_bread(&it->buf, it->pos, true);
+ if (IS_ERR(it->kaddr))
+ return PTR_ERR(it->kaddr);
+
+ entry_sz = erofs_xattr_entry_size(it->kaddr);
+ /* xattr on-disk corruption: xattr entry beyond xattr_isize */
+ if (remaining < entry_sz) {
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
+ remaining -= entry_sz;
+ next_pos = it->pos + entry_sz;
+
+ if (getxattr)
+ ret = erofs_getxattr_foreach(it);
+ else
+ ret = erofs_listxattr_foreach(it);
+ if ((getxattr && ret != -ENODATA) || (!getxattr && ret))
+ break;
+
+ it->pos = next_pos;
+ }
+ return ret;
+}
+
+static int erofs_xattr_iter_shared(struct erofs_xattr_iter *it,
+ struct inode *inode, bool getxattr)
+{
+ struct erofs_inode *const vi = EROFS_I(inode);
+ struct super_block *const sb = it->sb;
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ unsigned int i = 0;
+ int ret;
+
+ ret = erofs_init_metabuf(&it->buf, sb,
+ erofs_sb_has_shared_ea_in_metabox(sbi));
+ if (ret)
+ return ret;
+
+ while (i < vi->xattr_shared_count) {
+ it->pos = erofs_pos(sb, sbi->xattr_blkaddr) +
+ vi->xattr_shared_xattrs[i++] * sizeof(__le32);
+ it->kaddr = erofs_bread(&it->buf, it->pos, true);
+ if (IS_ERR(it->kaddr))
+ return PTR_ERR(it->kaddr);
+
+ if (getxattr)
+ ret = erofs_getxattr_foreach(it);
+ else
+ ret = erofs_listxattr_foreach(it);
+ if ((getxattr && ret != -ENODATA) || (!getxattr && ret))
+ break;
+ }
+ return i ? ret : -ENODATA;
+}
+
+static int erofs_getxattr(struct inode *inode, int index, const char *name,
+ void *buffer, size_t buffer_size)
+{
+ int ret;
+ unsigned int hashbit;
+ struct erofs_xattr_iter it;
+ struct erofs_inode *vi = EROFS_I(inode);
+ struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
+
+ if (!name)
+ return -EINVAL;
+
+ ret = erofs_init_inode_xattrs(inode);
+ if (ret)
+ return ret;
+
+ /* reserved flag is non-zero if there's any change of on-disk format */
+ if (erofs_sb_has_xattr_filter(sbi) && !sbi->xattr_filter_reserved) {
+ hashbit = xxh32(name, strlen(name),
+ EROFS_XATTR_FILTER_SEED + index);
+ hashbit &= EROFS_XATTR_FILTER_BITS - 1;
+ if (vi->xattr_name_filter & (1U << hashbit))
+ return -ENODATA;
+ }
+
+ it.index = index;
+ it.name = QSTR(name);
+ if (it.name.len > EROFS_NAME_LEN)
+ return -ERANGE;
+
+ it.sb = inode->i_sb;
+ it.buf = __EROFS_BUF_INITIALIZER;
+ it.buffer = buffer;
+ it.buffer_size = buffer_size;
+ it.buffer_ofs = 0;
+
+ ret = erofs_xattr_iter_inline(&it, inode, true);
+ if (ret == -ENODATA)
+ ret = erofs_xattr_iter_shared(&it, inode, true);
+ erofs_put_metabuf(&it.buf);
+ return ret ? ret : it.buffer_ofs;
+}
+
+ssize_t erofs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
+{
+ int ret;
+ struct erofs_xattr_iter it;
+ struct inode *inode = d_inode(dentry);
+
+ ret = erofs_init_inode_xattrs(inode);
+ if (ret == -ENODATA)
+ return 0;
+ if (ret)
+ return ret;
+
+ it.sb = dentry->d_sb;
+ it.buf = __EROFS_BUF_INITIALIZER;
+ it.dentry = dentry;
+ it.buffer = buffer;
+ it.buffer_size = buffer_size;
+ it.buffer_ofs = 0;
+
+ ret = erofs_xattr_iter_inline(&it, inode, false);
+ if (!ret || ret == -ENODATA)
+ ret = erofs_xattr_iter_shared(&it, inode, false);
+ if (ret == -ENODATA)
+ ret = 0;
+ erofs_put_metabuf(&it.buf);
+ return ret ? ret : it.buffer_ofs;
+}
+
+static bool erofs_xattr_user_list(struct dentry *dentry)
+{
+ return test_opt(&EROFS_SB(dentry->d_sb)->opt, XATTR_USER);
+}
+
+static bool erofs_xattr_trusted_list(struct dentry *dentry)
+{
+ return capable(CAP_SYS_ADMIN);
+}
+
+static int erofs_xattr_generic_get(const struct xattr_handler *handler,
+ struct dentry *unused, struct inode *inode,
+ const char *name, void *buffer, size_t size)
+{
+ if (handler->flags == EROFS_XATTR_INDEX_USER &&
+ !test_opt(&EROFS_I_SB(inode)->opt, XATTR_USER))
+ return -EOPNOTSUPP;
+
+ return erofs_getxattr(inode, handler->flags, name, buffer, size);
+}
+
+static const struct xattr_handler erofs_xattr_user_handler = {
+ .prefix = XATTR_USER_PREFIX,
+ .flags = EROFS_XATTR_INDEX_USER,
+ .list = erofs_xattr_user_list,
+ .get = erofs_xattr_generic_get,
+};
+
+static const struct xattr_handler erofs_xattr_trusted_handler = {
+ .prefix = XATTR_TRUSTED_PREFIX,
+ .flags = EROFS_XATTR_INDEX_TRUSTED,
+ .list = erofs_xattr_trusted_list,
+ .get = erofs_xattr_generic_get,
+};
+
+#ifdef CONFIG_EROFS_FS_SECURITY
+static const struct xattr_handler erofs_xattr_security_handler = {
+ .prefix = XATTR_SECURITY_PREFIX,
+ .flags = EROFS_XATTR_INDEX_SECURITY,
+ .get = erofs_xattr_generic_get,
+};
+#endif
+
+const struct xattr_handler * const erofs_xattr_handlers[] = {
+ &erofs_xattr_user_handler,
+ &erofs_xattr_trusted_handler,
+#ifdef CONFIG_EROFS_FS_SECURITY
+ &erofs_xattr_security_handler,
+#endif
+ NULL,
+};
+
+static const char *erofs_xattr_prefix(unsigned int idx, struct dentry *dentry)
+{
+ static const struct xattr_handler * const xattr_handler_map[] = {
+ [EROFS_XATTR_INDEX_USER] = &erofs_xattr_user_handler,
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+ [EROFS_XATTR_INDEX_POSIX_ACL_ACCESS] = &nop_posix_acl_access,
+ [EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &nop_posix_acl_default,
+#endif
+ [EROFS_XATTR_INDEX_TRUSTED] = &erofs_xattr_trusted_handler,
+#ifdef CONFIG_EROFS_FS_SECURITY
+ [EROFS_XATTR_INDEX_SECURITY] = &erofs_xattr_security_handler,
+#endif
+ };
+ const struct xattr_handler *handler = NULL;
+
+ if (idx && idx < ARRAY_SIZE(xattr_handler_map)) {
+ handler = xattr_handler_map[idx];
+ if (xattr_handler_can_list(handler, dentry))
+ return xattr_prefix(handler);
+ }
+ return NULL;
+}
+
+void erofs_xattr_prefixes_cleanup(struct super_block *sb)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ int i;
+
+ if (sbi->xattr_prefixes) {
+ for (i = 0; i < sbi->xattr_prefix_count; i++)
+ kfree(sbi->xattr_prefixes[i].prefix);
+ kfree(sbi->xattr_prefixes);
+ sbi->xattr_prefixes = NULL;
+ }
+}
+
+int erofs_xattr_prefixes_init(struct super_block *sb)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+ erofs_off_t pos = (erofs_off_t)sbi->xattr_prefix_start << 2;
+ struct erofs_xattr_prefix_item *pfs;
+ int ret = 0, i, len;
+ bool plain = erofs_sb_has_plain_xattr_pfx(sbi);
+
+ if (!sbi->xattr_prefix_count)
+ return 0;
+
+ pfs = kzalloc_objs(*pfs, sbi->xattr_prefix_count);
+ if (!pfs)
+ return -ENOMEM;
+
+ if (!plain) {
+ if (erofs_sb_has_metabox(sbi))
+ (void)erofs_init_metabuf(&buf, sb, true);
+ else if (sbi->packed_inode)
+ buf.mapping = sbi->packed_inode->i_mapping;
+ else
+ plain = true;
+ }
+ if (plain)
+ (void)erofs_init_metabuf(&buf, sb, false);
+
+ for (i = 0; i < sbi->xattr_prefix_count; i++) {
+ void *ptr = erofs_read_metadata(sb, &buf, &pos, &len);
+
+ if (IS_ERR(ptr)) {
+ ret = PTR_ERR(ptr);
+ break;
+ } else if (len < sizeof(*pfs->prefix) ||
+ len > EROFS_NAME_LEN + sizeof(*pfs->prefix)) {
+ kfree(ptr);
+ ret = -EFSCORRUPTED;
+ break;
+ }
+ pfs[i].prefix = ptr;
+ pfs[i].infix_len = len - sizeof(struct erofs_xattr_long_prefix);
+ }
+
+ erofs_put_metabuf(&buf);
+ if (!ret && erofs_sb_has_ishare_xattrs(sbi)) {
+ struct erofs_xattr_prefix_item *pf = pfs + sbi->ishare_xattr_prefix_id;
+ struct erofs_xattr_long_prefix *newpfx;
+
+ newpfx = krealloc(pf->prefix,
+ sizeof(*newpfx) + pf->infix_len + 1, GFP_KERNEL);
+ if (newpfx) {
+ newpfx->infix[pf->infix_len] = '\0';
+ pf->prefix = newpfx;
+ } else {
+ ret = -ENOMEM;
+ }
+ }
+ sbi->xattr_prefixes = pfs;
+ if (ret)
+ erofs_xattr_prefixes_cleanup(sb);
+ return ret;
+}
+
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+struct posix_acl *erofs_get_acl(struct inode *inode, int type, bool rcu)
+{
+ struct posix_acl *acl;
+ int prefix, rc;
+ char *value = NULL;
+
+ if (rcu)
+ return ERR_PTR(-ECHILD);
+
+ switch (type) {
+ case ACL_TYPE_ACCESS:
+ prefix = EROFS_XATTR_INDEX_POSIX_ACL_ACCESS;
+ break;
+ case ACL_TYPE_DEFAULT:
+ prefix = EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT;
+ break;
+ default:
+ return ERR_PTR(-EINVAL);
+ }
+
+ rc = erofs_getxattr(inode, prefix, "", NULL, 0);
+ if (rc > 0) {
+ value = kmalloc(rc, GFP_KERNEL);
+ if (!value)
+ return ERR_PTR(-ENOMEM);
+ rc = erofs_getxattr(inode, prefix, "", value, rc);
+ }
+
+ if (rc == -ENODATA)
+ acl = NULL;
+ else if (rc < 0)
+ acl = ERR_PTR(rc);
+ else
+ acl = posix_acl_from_xattr(&init_user_ns, value, rc);
+ kfree(value);
+ return acl;
+}
+
+bool erofs_inode_has_noacl(struct inode *inode, void *kaddr, unsigned int ofs)
+{
+ static const unsigned int bitmask =
+ BIT(21) | /* system.posix_acl_default */
+ BIT(30); /* system.posix_acl_access */
+ struct erofs_sb_info *sbi = EROFS_I_SB(inode);
+ const struct erofs_xattr_ibody_header *ih = kaddr + ofs;
+
+ if (EROFS_I(inode)->xattr_isize < sizeof(*ih))
+ return true;
+
+ if (erofs_sb_has_xattr_filter(sbi) && !sbi->xattr_filter_reserved &&
+ !check_add_overflow(ofs, sizeof(*ih), &ofs) &&
+ ofs <= i_blocksize(inode)) {
+ if ((le32_to_cpu(ih->h_name_filter) & bitmask) == bitmask)
+ return true;
+ }
+ return false;
+}
+#endif
+
+#ifdef CONFIG_EROFS_FS_PAGE_CACHE_SHARE
+int erofs_xattr_fill_inode_fingerprint(struct erofs_inode_fingerprint *fp,
+ struct inode *inode, const char *domain_id)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
+ struct erofs_xattr_prefix_item *prefix;
+ const char *infix;
+ int valuelen, base_index;
+
+ if (!test_opt(&sbi->opt, INODE_SHARE))
+ return -EOPNOTSUPP;
+ if (!sbi->xattr_prefixes)
+ return -EINVAL;
+ prefix = sbi->xattr_prefixes + sbi->ishare_xattr_prefix_id;
+ infix = prefix->prefix->infix;
+ base_index = prefix->prefix->base_index;
+ valuelen = erofs_getxattr(inode, base_index, infix, NULL, 0);
+ if (valuelen <= 0 || valuelen > (1 << sbi->blkszbits))
+ return -EFSCORRUPTED;
+ fp->size = valuelen + (domain_id ? strlen(domain_id) : 0);
+ fp->opaque = kmalloc(fp->size, GFP_KERNEL);
+ if (!fp->opaque)
+ return -ENOMEM;
+ if (valuelen != erofs_getxattr(inode, base_index, infix,
+ fp->opaque, valuelen)) {
+ kfree(fp->opaque);
+ fp->opaque = NULL;
+ return -EFSCORRUPTED;
+ }
+ memcpy(fp->opaque + valuelen, domain_id, fp->size - valuelen);
+ return 0;
+}
+#endif
diff --git a/fs/erofs/xattr.h b/fs/erofs/xattr.h
new file mode 100644
index 000000000..4465f7018
--- /dev/null
+++ b/fs/erofs/xattr.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ * https://www.huawei.com/
+ */
+#ifndef __EROFS_XATTR_H
+#define __EROFS_XATTR_H
+
+#include "internal.h"
+#include <linux/posix_acl_xattr.h>
+#include <linux/xattr.h>
+
+#ifdef CONFIG_EROFS_FS_XATTR
+extern const struct xattr_handler * const erofs_xattr_handlers[];
+
+int erofs_xattr_prefixes_init(struct super_block *sb);
+void erofs_xattr_prefixes_cleanup(struct super_block *sb);
+ssize_t erofs_listxattr(struct dentry *, char *, size_t);
+#else
+static inline int erofs_xattr_prefixes_init(struct super_block *sb) { return 0; }
+static inline void erofs_xattr_prefixes_cleanup(struct super_block *sb) {}
+
+#define erofs_listxattr (NULL)
+#define erofs_xattr_handlers (NULL)
+#endif /* !CONFIG_EROFS_FS_XATTR */
+
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+struct posix_acl *erofs_get_acl(struct inode *inode, int type, bool rcu);
+#else
+#define erofs_get_acl (NULL)
+#endif
+
+int erofs_xattr_fill_inode_fingerprint(struct erofs_inode_fingerprint *fp,
+ struct inode *inode, const char *domain_id);
+bool erofs_inode_has_noacl(struct inode *inode, void *kaddr, unsigned int ofs);
+#endif
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
new file mode 100644
index 000000000..e1e25ca0d
--- /dev/null
+++ b/fs/erofs/zdata.c
@@ -0,0 +1,1935 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2018 HUAWEI, Inc.
+ * https://www.huawei.com/
+ * Copyright (C) 2022 Alibaba Cloud
+ */
+#include "compress.h"
+#include <linux/psi.h>
+#include <linux/cpuhotplug.h>
+#include <trace/events/erofs.h>
+
+#define Z_EROFS_MAX_SYNC_DECOMPRESS_BYTES 12288
+#define Z_EROFS_PCLUSTER_MAX_PAGES (Z_EROFS_PCLUSTER_MAX_SIZE / PAGE_SIZE)
+#define Z_EROFS_INLINE_BVECS 2
+
+struct z_erofs_bvec {
+ struct page *page;
+ int offset;
+ unsigned int end;
+};
+
+#define __Z_EROFS_BVSET(name, total) \
+struct name { \
+ /* point to the next page which contains the following bvecs */ \
+ struct page *nextpage; \
+ struct z_erofs_bvec bvec[total]; \
+}
+__Z_EROFS_BVSET(z_erofs_bvset,);
+__Z_EROFS_BVSET(z_erofs_bvset_inline, Z_EROFS_INLINE_BVECS);
+
+/*
+ * Structure fields follow one of the following exclusion rules.
+ *
+ * I: Modifiable by initialization/destruction paths and read-only
+ * for everyone else;
+ *
+ * L: Field should be protected by the pcluster lock;
+ *
+ * A: Field should be accessed / updated in atomic for parallelized code.
+ */
+struct z_erofs_pcluster {
+ struct mutex lock;
+ struct lockref lockref;
+
+ /* A: point to next chained pcluster or TAILs */
+ struct z_erofs_pcluster *next;
+
+ /* I: start physical position of this pcluster */
+ erofs_off_t pos;
+
+ /* L: the maximum decompression size of this round */
+ unsigned int length;
+
+ /* L: total number of bvecs */
+ unsigned int vcnt;
+
+ /* I: pcluster size (compressed size) in bytes */
+ unsigned int pclustersize;
+
+ /* I: page offset of start position of decompression */
+ unsigned short pageofs_out;
+
+ /* I: page offset of inline compressed data */
+ unsigned short pageofs_in;
+
+ union {
+ /* L: inline a certain number of bvec for bootstrap */
+ struct z_erofs_bvset_inline bvset;
+
+ /* I: can be used to free the pcluster by RCU. */
+ struct rcu_head rcu;
+ };
+
+ /* I: compression algorithm format */
+ unsigned char algorithmformat;
+
+ /* I: whether compressed data is in-lined or not */
+ bool from_meta;
+
+ /* L: whether partial decompression or not */
+ bool partial;
+
+ /* L: whether extra buffer allocations are best-effort */
+ bool besteffort;
+
+ /* A: compressed bvecs (can be cached or inplaced pages) */
+ struct z_erofs_bvec compressed_bvecs[];
+};
+
+/* the end of a chain of pclusters */
+#define Z_EROFS_PCLUSTER_TAIL ((void *) 0x700 + POISON_POINTER_DELTA)
+
+struct z_erofs_decompressqueue {
+ struct super_block *sb;
+ struct z_erofs_pcluster *head;
+ atomic_t pending_bios;
+
+ union {
+ struct completion done;
+ struct work_struct work;
+ struct kthread_work kthread_work;
+ } u;
+ bool eio, sync;
+};
+
+static inline unsigned int z_erofs_pclusterpages(struct z_erofs_pcluster *pcl)
+{
+ return PAGE_ALIGN(pcl->pageofs_in + pcl->pclustersize) >> PAGE_SHIFT;
+}
+
+static bool erofs_folio_is_managed(struct erofs_sb_info *sbi, struct folio *fo)
+{
+ return fo->mapping == MNGD_MAPPING(sbi);
+}
+
+#define Z_EROFS_ONSTACK_PAGES 32
+
+/*
+ * since pclustersize is variable for big pcluster feature, introduce slab
+ * pools implementation for different pcluster sizes.
+ */
+struct z_erofs_pcluster_slab {
+ struct kmem_cache *slab;
+ unsigned int maxpages;
+ char name[48];
+};
+
+#define _PCLP(n) { .maxpages = n }
+
+static struct z_erofs_pcluster_slab pcluster_pool[] __read_mostly = {
+ _PCLP(1),
+ _PCLP(4),
+#if Z_EROFS_PCLUSTER_MAX_PAGES > 16
+ _PCLP(16),
+#endif
+#if Z_EROFS_PCLUSTER_MAX_PAGES > 64
+ _PCLP(64),
+#endif
+#if Z_EROFS_PCLUSTER_MAX_PAGES > 128
+ _PCLP(128),
+#endif
+ _PCLP(Z_EROFS_PCLUSTER_MAX_PAGES + 1)
+};
+
+struct z_erofs_bvec_iter {
+ struct page *bvpage;
+ struct z_erofs_bvset *bvset;
+ unsigned int nr, cur;
+};
+
+static struct page *z_erofs_bvec_iter_end(struct z_erofs_bvec_iter *iter)
+{
+ if (iter->bvpage)
+ kunmap_local(iter->bvset);
+ return iter->bvpage;
+}
+
+static struct page *z_erofs_bvset_flip(struct z_erofs_bvec_iter *iter)
+{
+ unsigned long base = (unsigned long)((struct z_erofs_bvset *)0)->bvec;
+ /* have to access nextpage in advance, otherwise it will be unmapped */
+ struct page *nextpage = iter->bvset->nextpage;
+ struct page *oldpage;
+
+ DBG_BUGON(!nextpage);
+ oldpage = z_erofs_bvec_iter_end(iter);
+ iter->bvpage = nextpage;
+ iter->bvset = kmap_local_page(nextpage);
+ iter->nr = (PAGE_SIZE - base) / sizeof(struct z_erofs_bvec);
+ iter->cur = 0;
+ return oldpage;
+}
+
+static void z_erofs_bvec_iter_begin(struct z_erofs_bvec_iter *iter,
+ struct z_erofs_bvset_inline *bvset,
+ unsigned int bootstrap_nr,
+ unsigned int cur)
+{
+ *iter = (struct z_erofs_bvec_iter) {
+ .nr = bootstrap_nr,
+ .bvset = (struct z_erofs_bvset *)bvset,
+ };
+
+ while (cur > iter->nr) {
+ cur -= iter->nr;
+ z_erofs_bvset_flip(iter);
+ }
+ iter->cur = cur;
+}
+
+static int z_erofs_bvec_enqueue(struct z_erofs_bvec_iter *iter,
+ struct z_erofs_bvec *bvec,
+ struct page **candidate_bvpage,
+ struct page **pagepool)
+{
+ if (iter->cur >= iter->nr) {
+ struct page *nextpage = *candidate_bvpage;
+
+ if (!nextpage) {
+ nextpage = __erofs_allocpage(pagepool, GFP_KERNEL,
+ true);
+ if (!nextpage)
+ return -ENOMEM;
+ set_page_private(nextpage, Z_EROFS_SHORTLIVED_PAGE);
+ }
+ DBG_BUGON(iter->bvset->nextpage);
+ iter->bvset->nextpage = nextpage;
+ z_erofs_bvset_flip(iter);
+
+ iter->bvset->nextpage = NULL;
+ *candidate_bvpage = NULL;
+ }
+ iter->bvset->bvec[iter->cur++] = *bvec;
+ return 0;
+}
+
+static void z_erofs_bvec_dequeue(struct z_erofs_bvec_iter *iter,
+ struct z_erofs_bvec *bvec,
+ struct page **old_bvpage)
+{
+ if (iter->cur == iter->nr)
+ *old_bvpage = z_erofs_bvset_flip(iter);
+ else
+ *old_bvpage = NULL;
+ *bvec = iter->bvset->bvec[iter->cur++];
+}
+
+static void z_erofs_destroy_pcluster_pool(void)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(pcluster_pool); ++i) {
+ if (!pcluster_pool[i].slab)
+ continue;
+ kmem_cache_destroy(pcluster_pool[i].slab);
+ pcluster_pool[i].slab = NULL;
+ }
+}
+
+static int z_erofs_create_pcluster_pool(void)
+{
+ struct z_erofs_pcluster_slab *pcs;
+ struct z_erofs_pcluster *a;
+ unsigned int size;
+
+ for (pcs = pcluster_pool;
+ pcs < pcluster_pool + ARRAY_SIZE(pcluster_pool); ++pcs) {
+ size = struct_size(a, compressed_bvecs, pcs->maxpages);
+
+ sprintf(pcs->name, "erofs_pcluster-%u", pcs->maxpages);
+ pcs->slab = kmem_cache_create(pcs->name, size, 0,
+ SLAB_RECLAIM_ACCOUNT, NULL);
+ if (pcs->slab)
+ continue;
+
+ z_erofs_destroy_pcluster_pool();
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+static struct z_erofs_pcluster *z_erofs_alloc_pcluster(unsigned int size)
+{
+ unsigned int nrpages = PAGE_ALIGN(size) >> PAGE_SHIFT;
+ struct z_erofs_pcluster_slab *pcs = pcluster_pool;
+
+ for (; pcs < pcluster_pool + ARRAY_SIZE(pcluster_pool); ++pcs) {
+ struct z_erofs_pcluster *pcl;
+
+ if (nrpages > pcs->maxpages)
+ continue;
+
+ pcl = kmem_cache_zalloc(pcs->slab, GFP_KERNEL);
+ if (!pcl)
+ return ERR_PTR(-ENOMEM);
+ return pcl;
+ }
+ return ERR_PTR(-EINVAL);
+}
+
+static void z_erofs_free_pcluster(struct z_erofs_pcluster *pcl)
+{
+ unsigned int pclusterpages = z_erofs_pclusterpages(pcl);
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(pcluster_pool); ++i) {
+ struct z_erofs_pcluster_slab *pcs = pcluster_pool + i;
+
+ if (pclusterpages > pcs->maxpages)
+ continue;
+
+ kmem_cache_free(pcs->slab, pcl);
+ return;
+ }
+ DBG_BUGON(1);
+}
+
+static struct workqueue_struct *z_erofs_workqueue __read_mostly;
+
+#ifdef CONFIG_EROFS_FS_PCPU_KTHREAD
+static struct kthread_worker __rcu **z_erofs_pcpu_workers;
+static atomic_t erofs_percpu_workers_initialized = ATOMIC_INIT(0);
+
+static void erofs_destroy_percpu_workers(void)
+{
+ struct kthread_worker *worker;
+ unsigned int cpu;
+
+ for_each_possible_cpu(cpu) {
+ worker = rcu_dereference_protected(
+ z_erofs_pcpu_workers[cpu], 1);
+ rcu_assign_pointer(z_erofs_pcpu_workers[cpu], NULL);
+ if (worker)
+ kthread_destroy_worker(worker);
+ }
+ kfree(z_erofs_pcpu_workers);
+}
+
+static struct kthread_worker *erofs_init_percpu_worker(int cpu)
+{
+ struct kthread_worker *worker =
+ kthread_run_worker_on_cpu(cpu, 0, "erofs_worker/%u");
+
+ if (IS_ERR(worker))
+ return worker;
+ if (IS_ENABLED(CONFIG_EROFS_FS_PCPU_KTHREAD_HIPRI))
+ sched_set_fifo_low(worker->task);
+ return worker;
+}
+
+static int erofs_init_percpu_workers(void)
+{
+ struct kthread_worker *worker;
+ unsigned int cpu;
+
+ z_erofs_pcpu_workers = kzalloc_objs(struct kthread_worker *,
+ num_possible_cpus(), GFP_ATOMIC);
+ if (!z_erofs_pcpu_workers)
+ return -ENOMEM;
+
+ for_each_online_cpu(cpu) { /* could miss cpu{off,on}line? */
+ worker = erofs_init_percpu_worker(cpu);
+ if (!IS_ERR(worker))
+ rcu_assign_pointer(z_erofs_pcpu_workers[cpu], worker);
+ }
+ return 0;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static DEFINE_SPINLOCK(z_erofs_pcpu_worker_lock);
+static enum cpuhp_state erofs_cpuhp_state;
+
+static int erofs_cpu_online(unsigned int cpu)
+{
+ struct kthread_worker *worker, *old;
+
+ worker = erofs_init_percpu_worker(cpu);
+ if (IS_ERR(worker))
+ return PTR_ERR(worker);
+
+ spin_lock(&z_erofs_pcpu_worker_lock);
+ old = rcu_dereference_protected(z_erofs_pcpu_workers[cpu],
+ lockdep_is_held(&z_erofs_pcpu_worker_lock));
+ if (!old)
+ rcu_assign_pointer(z_erofs_pcpu_workers[cpu], worker);
+ spin_unlock(&z_erofs_pcpu_worker_lock);
+ if (old)
+ kthread_destroy_worker(worker);
+ return 0;
+}
+
+static int erofs_cpu_offline(unsigned int cpu)
+{
+ struct kthread_worker *worker;
+
+ spin_lock(&z_erofs_pcpu_worker_lock);
+ worker = rcu_dereference_protected(z_erofs_pcpu_workers[cpu],
+ lockdep_is_held(&z_erofs_pcpu_worker_lock));
+ rcu_assign_pointer(z_erofs_pcpu_workers[cpu], NULL);
+ spin_unlock(&z_erofs_pcpu_worker_lock);
+
+ synchronize_rcu();
+ if (worker)
+ kthread_destroy_worker(worker);
+ return 0;
+}
+
+static int erofs_cpu_hotplug_init(void)
+{
+ int state;
+
+ state = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
+ "fs/erofs:online", erofs_cpu_online, erofs_cpu_offline);
+ if (state < 0)
+ return state;
+
+ erofs_cpuhp_state = state;
+ return 0;
+}
+
+static void erofs_cpu_hotplug_destroy(void)
+{
+ if (erofs_cpuhp_state)
+ cpuhp_remove_state_nocalls(erofs_cpuhp_state);
+}
+#else /* !CONFIG_HOTPLUG_CPU */
+static inline int erofs_cpu_hotplug_init(void) { return 0; }
+static inline void erofs_cpu_hotplug_destroy(void) {}
+#endif/* CONFIG_HOTPLUG_CPU */
+static int z_erofs_init_pcpu_workers(struct super_block *sb)
+{
+ int err;
+
+ if (atomic_xchg(&erofs_percpu_workers_initialized, 1))
+ return 0;
+
+ err = erofs_init_percpu_workers();
+ if (err) {
+ erofs_err(sb, "per-cpu workers: failed to allocate.");
+ goto err_init_percpu_workers;
+ }
+
+ err = erofs_cpu_hotplug_init();
+ if (err < 0) {
+ erofs_err(sb, "per-cpu workers: failed CPU hotplug init.");
+ goto err_cpuhp_init;
+ }
+ erofs_info(sb, "initialized per-cpu workers successfully.");
+ return err;
+
+err_cpuhp_init:
+ erofs_destroy_percpu_workers();
+err_init_percpu_workers:
+ atomic_set(&erofs_percpu_workers_initialized, 0);
+ return err;
+}
+
+static void z_erofs_destroy_pcpu_workers(void)
+{
+ if (!atomic_xchg(&erofs_percpu_workers_initialized, 0))
+ return;
+ erofs_cpu_hotplug_destroy();
+ erofs_destroy_percpu_workers();
+}
+#else /* !CONFIG_EROFS_FS_PCPU_KTHREAD */
+static inline int z_erofs_init_pcpu_workers(struct super_block *sb) { return 0; }
+static inline void z_erofs_destroy_pcpu_workers(void) {}
+#endif/* CONFIG_EROFS_FS_PCPU_KTHREAD */
+
+void z_erofs_exit_subsystem(void)
+{
+ z_erofs_destroy_pcpu_workers();
+ destroy_workqueue(z_erofs_workqueue);
+ z_erofs_destroy_pcluster_pool();
+ z_erofs_crypto_disable_all_engines();
+ z_erofs_exit_decompressor();
+}
+
+int __init z_erofs_init_subsystem(void)
+{
+ int err = z_erofs_init_decompressor();
+
+ if (err)
+ goto err_decompressor;
+
+ err = z_erofs_create_pcluster_pool();
+ if (err)
+ goto err_pcluster_pool;
+
+ z_erofs_workqueue = alloc_workqueue("erofs_worker",
+ WQ_UNBOUND | WQ_HIGHPRI, num_possible_cpus());
+ if (!z_erofs_workqueue) {
+ err = -ENOMEM;
+ goto err_workqueue_init;
+ }
+
+ return err;
+
+err_workqueue_init:
+ z_erofs_destroy_pcluster_pool();
+err_pcluster_pool:
+ z_erofs_exit_decompressor();
+err_decompressor:
+ return err;
+}
+
+enum z_erofs_pclustermode {
+ /* It has previously been linked into another processing chain */
+ Z_EROFS_PCLUSTER_INFLIGHT,
+ /*
+ * A weaker form of Z_EROFS_PCLUSTER_FOLLOWED; the difference is that it
+ * may be dispatched to the bypass queue later due to uptodated managed
+ * folios. All file-backed folios related to this pcluster cannot be
+ * reused for in-place I/O (or bvpage) since the pcluster may be decoded
+ * in a separate queue (and thus out of order).
+ */
+ Z_EROFS_PCLUSTER_FOLLOWED_NOINPLACE,
+ /*
+ * The pcluster has just been linked to our processing chain.
+ * File-backed folios (except for the head page) related to it can be
+ * used for in-place I/O (or bvpage).
+ */
+ Z_EROFS_PCLUSTER_FOLLOWED,
+};
+
+struct z_erofs_frontend {
+ struct inode *inode, *sharedinode;
+ struct erofs_map_blocks map;
+ struct z_erofs_bvec_iter biter;
+
+ struct page *pagepool;
+ struct page *candidate_bvpage;
+ struct z_erofs_pcluster *pcl, *head;
+ enum z_erofs_pclustermode mode;
+
+ erofs_off_t headoffset;
+
+ /* a pointer used to pick up inplace I/O pages */
+ unsigned int icur;
+};
+
+#define Z_EROFS_DEFINE_FRONTEND(fe, i, si, ho) struct z_erofs_frontend fe = { \
+ .inode = i, .sharedinode = si, .head = Z_EROFS_PCLUSTER_TAIL, \
+ .mode = Z_EROFS_PCLUSTER_FOLLOWED, .headoffset = ho }
+
+static bool z_erofs_should_alloc_cache(struct z_erofs_frontend *fe)
+{
+ unsigned int cachestrategy = EROFS_I_SB(fe->inode)->opt.cache_strategy;
+
+ if (cachestrategy <= EROFS_ZIP_CACHE_DISABLED)
+ return false;
+
+ if (fe->map.m_flags & EROFS_MAP_PARTIAL_MAPPED)
+ return true;
+
+ if (cachestrategy >= EROFS_ZIP_CACHE_READAROUND &&
+ fe->map.m_la < fe->headoffset)
+ return true;
+
+ return false;
+}
+
+static void z_erofs_bind_cache(struct z_erofs_frontend *fe)
+{
+ struct address_space *mc = MNGD_MAPPING(EROFS_I_SB(fe->inode));
+ struct z_erofs_pcluster *pcl = fe->pcl;
+ unsigned int pclusterpages = z_erofs_pclusterpages(pcl);
+ bool shouldalloc = z_erofs_should_alloc_cache(fe);
+ pgoff_t poff = pcl->pos >> PAGE_SHIFT;
+ bool may_bypass = true;
+ /* Optimistic allocation, as in-place I/O can be used as a fallback */
+ gfp_t gfp = (mapping_gfp_mask(mc) & ~__GFP_DIRECT_RECLAIM) |
+ __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
+ struct folio *folio, *newfolio;
+ unsigned int i;
+
+ if (i_blocksize(fe->inode) != PAGE_SIZE ||
+ fe->mode < Z_EROFS_PCLUSTER_FOLLOWED)
+ return;
+
+ for (i = 0; i < pclusterpages; ++i) {
+ /* Inaccurate check w/o locking to avoid unneeded lookups */
+ if (READ_ONCE(pcl->compressed_bvecs[i].page))
+ continue;
+
+ folio = filemap_get_folio(mc, poff + i);
+ if (IS_ERR(folio)) {
+ may_bypass = false;
+ if (!shouldalloc)
+ continue;
+
+ /*
+ * Allocate a managed folio for cached I/O, or it may be
+ * then filled with a file-backed folio for in-place I/O
+ */
+ newfolio = filemap_alloc_folio(gfp, 0, NULL);
+ if (!newfolio)
+ continue;
+ newfolio->private = Z_EROFS_PREALLOCATED_FOLIO;
+ folio = NULL;
+ }
+ spin_lock(&pcl->lockref.lock);
+ if (!pcl->compressed_bvecs[i].page) {
+ pcl->compressed_bvecs[i].page =
+ folio_page(folio ?: newfolio, 0);
+ spin_unlock(&pcl->lockref.lock);
+ continue;
+ }
+ spin_unlock(&pcl->lockref.lock);
+ folio_put(folio ?: newfolio);
+ }
+
+ /*
+ * Don't perform in-place I/O if all compressed pages are available in
+ * the managed cache, as the pcluster can be moved to the bypass queue.
+ */
+ if (may_bypass)
+ fe->mode = Z_EROFS_PCLUSTER_FOLLOWED_NOINPLACE;
+}
+
+/* (erofs_shrinker) disconnect cached encoded data with pclusters */
+static int erofs_try_to_free_all_cached_folios(struct erofs_sb_info *sbi,
+ struct z_erofs_pcluster *pcl)
+{
+ unsigned int pclusterpages = z_erofs_pclusterpages(pcl);
+ struct folio *folio;
+ int i;
+
+ DBG_BUGON(pcl->from_meta);
+ /* Each cached folio contains one page unless bs > ps is supported */
+ for (i = 0; i < pclusterpages; ++i) {
+ if (pcl->compressed_bvecs[i].page) {
+ folio = page_folio(pcl->compressed_bvecs[i].page);
+ /* Avoid reclaiming or migrating this folio */
+ if (!folio_trylock(folio))
+ return -EBUSY;
+
+ DBG_BUGON(!erofs_folio_is_managed(sbi, folio));
+ pcl->compressed_bvecs[i].page = NULL;
+ folio_detach_private(folio);
+ folio_unlock(folio);
+ }
+ }
+ return 0;
+}
+
+static bool z_erofs_cache_release_folio(struct folio *folio, gfp_t gfp)
+{
+ struct z_erofs_pcluster *pcl = folio_get_private(folio);
+ struct z_erofs_bvec *bvec = pcl->compressed_bvecs;
+ struct z_erofs_bvec *end = bvec + z_erofs_pclusterpages(pcl);
+ bool ret;
+
+ if (!folio_test_private(folio))
+ return true;
+
+ ret = false;
+ spin_lock(&pcl->lockref.lock);
+ if (pcl->lockref.count <= 0) {
+ DBG_BUGON(pcl->from_meta);
+ for (; bvec < end; ++bvec) {
+ if (bvec->page && page_folio(bvec->page) == folio) {
+ bvec->page = NULL;
+ folio_detach_private(folio);
+ ret = true;
+ break;
+ }
+ }
+ }
+ spin_unlock(&pcl->lockref.lock);
+ return ret;
+}
+
+/*
+ * It will be called only on inode eviction. In case that there are still some
+ * decompression requests in progress, wait with rescheduling for a bit here.
+ * An extra lock could be introduced instead but it seems unnecessary.
+ */
+static void z_erofs_cache_invalidate_folio(struct folio *folio,
+ size_t offset, size_t length)
+{
+ const size_t stop = length + offset;
+
+ /* Check for potential overflow in debug mode */
+ DBG_BUGON(stop > folio_size(folio) || stop < length);
+
+ if (offset == 0 && stop == folio_size(folio))
+ while (!z_erofs_cache_release_folio(folio, 0))
+ cond_resched();
+}
+
+static const struct address_space_operations z_erofs_cache_aops = {
+ .release_folio = z_erofs_cache_release_folio,
+ .invalidate_folio = z_erofs_cache_invalidate_folio,
+};
+
+int z_erofs_init_super(struct super_block *sb)
+{
+ int err;
+
+ err = z_erofs_init_pcpu_workers(sb);
+ if (err)
+ return err;
+
+ err = erofs_setup_managed_cache(sb);
+ if (err)
+ return err;
+ EROFS_SB(sb)->managed_cache->i_mapping->a_ops = &z_erofs_cache_aops;
+ xa_init(&EROFS_SB(sb)->managed_pslots);
+ return 0;
+}
+
+/* callers must be with pcluster lock held */
+static int z_erofs_attach_page(struct z_erofs_frontend *fe,
+ struct z_erofs_bvec *bvec, bool exclusive)
+{
+ struct z_erofs_pcluster *pcl = fe->pcl;
+ int ret;
+
+ if (exclusive) {
+ /* Inplace I/O is limited to one page for uncompressed data */
+ if (pcl->algorithmformat < Z_EROFS_COMPRESSION_MAX ||
+ fe->icur <= 1) {
+ /* Try to prioritize inplace I/O here */
+ spin_lock(&pcl->lockref.lock);
+ while (fe->icur > 0) {
+ if (pcl->compressed_bvecs[--fe->icur].page)
+ continue;
+ pcl->compressed_bvecs[fe->icur] = *bvec;
+ spin_unlock(&pcl->lockref.lock);
+ return 0;
+ }
+ spin_unlock(&pcl->lockref.lock);
+ }
+
+ /* otherwise, check if it can be used as a bvpage */
+ if (fe->mode >= Z_EROFS_PCLUSTER_FOLLOWED &&
+ !fe->candidate_bvpage)
+ fe->candidate_bvpage = bvec->page;
+ }
+ ret = z_erofs_bvec_enqueue(&fe->biter, bvec, &fe->candidate_bvpage,
+ &fe->pagepool);
+ fe->pcl->vcnt += (ret >= 0);
+ return ret;
+}
+
+static bool z_erofs_get_pcluster(struct z_erofs_pcluster *pcl)
+{
+ if (lockref_get_not_zero(&pcl->lockref))
+ return true;
+
+ spin_lock(&pcl->lockref.lock);
+ if (lockref_is_dead(&pcl->lockref)) {
+ spin_unlock(&pcl->lockref.lock);
+ return false;
+ }
+
+ if (!pcl->lockref.count++)
+ atomic_long_dec(&erofs_global_shrink_cnt);
+ spin_unlock(&pcl->lockref.lock);
+ return true;
+}
+
+static int z_erofs_register_pcluster(struct z_erofs_frontend *fe)
+{
+ struct erofs_map_blocks *map = &fe->map;
+ struct super_block *sb = fe->inode->i_sb;
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ struct z_erofs_pcluster *pcl, *pre;
+ unsigned int pageofs_in;
+ int err;
+
+ pageofs_in = erofs_blkoff(sb, map->m_pa);
+ pcl = z_erofs_alloc_pcluster(pageofs_in + map->m_plen);
+ if (IS_ERR(pcl))
+ return PTR_ERR(pcl);
+
+ lockref_init(&pcl->lockref); /* one ref for this request */
+ pcl->algorithmformat = map->m_algorithmformat;
+ pcl->pclustersize = map->m_plen;
+ pcl->length = 0;
+ pcl->partial = true;
+ pcl->next = fe->head;
+ pcl->pos = map->m_pa;
+ pcl->pageofs_in = pageofs_in;
+ pcl->pageofs_out = map->m_la & ~PAGE_MASK;
+ pcl->from_meta = map->m_flags & EROFS_MAP_META;
+ fe->mode = Z_EROFS_PCLUSTER_FOLLOWED;
+
+ /*
+ * lock all primary followed works before visible to others
+ * and mutex_trylock *never* fails for a new pcluster.
+ */
+ mutex_init(&pcl->lock);
+ DBG_BUGON(!mutex_trylock(&pcl->lock));
+
+ if (!pcl->from_meta) {
+ while (1) {
+ xa_lock(&sbi->managed_pslots);
+ pre = __xa_cmpxchg(&sbi->managed_pslots, pcl->pos,
+ NULL, pcl, GFP_KERNEL);
+ if (!pre || xa_is_err(pre) || z_erofs_get_pcluster(pre)) {
+ xa_unlock(&sbi->managed_pslots);
+ break;
+ }
+ /* try to legitimize the current in-tree one */
+ xa_unlock(&sbi->managed_pslots);
+ cond_resched();
+ }
+ if (xa_is_err(pre)) {
+ err = xa_err(pre);
+ goto err_out;
+ } else if (pre) {
+ fe->pcl = pre;
+ err = -EEXIST;
+ goto err_out;
+ }
+ }
+ fe->head = fe->pcl = pcl;
+ return 0;
+
+err_out:
+ mutex_unlock(&pcl->lock);
+ z_erofs_free_pcluster(pcl);
+ return err;
+}
+
+static int z_erofs_pcluster_begin(struct z_erofs_frontend *fe)
+{
+ struct erofs_map_blocks *map = &fe->map;
+ struct super_block *sb = fe->inode->i_sb;
+ struct z_erofs_pcluster *pcl = NULL;
+ void *ptr = NULL;
+ bool needretry;
+ int ret;
+
+ DBG_BUGON(fe->pcl);
+ /* must be Z_EROFS_PCLUSTER_TAIL or pointed to previous pcluster */
+ DBG_BUGON(!fe->head);
+
+ if (map->m_flags & EROFS_MAP_META) {
+ ret = erofs_init_metabuf(&map->buf, sb,
+ erofs_inode_in_metabox(fe->inode));
+ if (ret)
+ return ret;
+ ptr = erofs_bread(&map->buf, map->m_pa, false);
+ if (IS_ERR(ptr)) {
+ erofs_err(sb, "failed to read inline data %pe @ pa %llu of nid %llu",
+ ptr, map->m_pa, EROFS_I(fe->inode)->nid);
+ return PTR_ERR(ptr);
+ }
+ ptr = map->buf.page;
+ } else {
+ do {
+ rcu_read_lock();
+ pcl = xa_load(&EROFS_SB(sb)->managed_pslots, map->m_pa);
+ needretry = pcl && !z_erofs_get_pcluster(pcl);
+ rcu_read_unlock();
+ } while (needretry);
+ }
+
+ if (pcl) {
+ DBG_BUGON(map->m_pa != pcl->pos);
+ fe->pcl = pcl;
+ ret = -EEXIST;
+ } else {
+ ret = z_erofs_register_pcluster(fe);
+ }
+
+ if (ret == -EEXIST) {
+ mutex_lock(&fe->pcl->lock);
+ /* check if this pcluster hasn't been linked into any chain. */
+ if (!cmpxchg(&fe->pcl->next, NULL, fe->head)) {
+ /* .. so it can be attached to our submission chain */
+ fe->head = fe->pcl;
+ fe->mode = Z_EROFS_PCLUSTER_FOLLOWED;
+ } else { /* otherwise, it belongs to an inflight chain */
+ fe->mode = Z_EROFS_PCLUSTER_INFLIGHT;
+ }
+ } else if (ret) {
+ return ret;
+ }
+
+ z_erofs_bvec_iter_begin(&fe->biter, &fe->pcl->bvset,
+ Z_EROFS_INLINE_BVECS, fe->pcl->vcnt);
+ if (!fe->pcl->from_meta) {
+ /* bind cache first when cached decompression is preferred */
+ z_erofs_bind_cache(fe);
+ } else {
+ folio_get(page_folio((struct page *)ptr));
+ WRITE_ONCE(fe->pcl->compressed_bvecs[0].page, ptr);
+ fe->pcl->pageofs_in = map->m_pa & ~PAGE_MASK;
+ fe->mode = Z_EROFS_PCLUSTER_FOLLOWED_NOINPLACE;
+ }
+ /* file-backed inplace I/O pages are traversed in reverse order */
+ fe->icur = z_erofs_pclusterpages(fe->pcl);
+ return 0;
+}
+
+static void z_erofs_rcu_callback(struct rcu_head *head)
+{
+ z_erofs_free_pcluster(container_of(head, struct z_erofs_pcluster, rcu));
+}
+
+static bool __erofs_try_to_release_pcluster(struct erofs_sb_info *sbi,
+ struct z_erofs_pcluster *pcl)
+{
+ if (pcl->lockref.count)
+ return false;
+
+ /*
+ * Note that all cached folios should be detached before deleted from
+ * the XArray. Otherwise some folios could be still attached to the
+ * orphan old pcluster when the new one is available in the tree.
+ */
+ if (erofs_try_to_free_all_cached_folios(sbi, pcl))
+ return false;
+
+ /*
+ * It's impossible to fail after the pcluster is freezed, but in order
+ * to avoid some race conditions, add a DBG_BUGON to observe this.
+ */
+ DBG_BUGON(__xa_erase(&sbi->managed_pslots, pcl->pos) != pcl);
+
+ lockref_mark_dead(&pcl->lockref);
+ return true;
+}
+
+static bool erofs_try_to_release_pcluster(struct erofs_sb_info *sbi,
+ struct z_erofs_pcluster *pcl)
+{
+ bool free;
+
+ spin_lock(&pcl->lockref.lock);
+ free = __erofs_try_to_release_pcluster(sbi, pcl);
+ spin_unlock(&pcl->lockref.lock);
+ if (free) {
+ atomic_long_dec(&erofs_global_shrink_cnt);
+ call_rcu(&pcl->rcu, z_erofs_rcu_callback);
+ }
+ return free;
+}
+
+unsigned long z_erofs_shrink_scan(struct erofs_sb_info *sbi, unsigned long nr)
+{
+ struct z_erofs_pcluster *pcl;
+ unsigned long index, freed = 0;
+
+ xa_lock(&sbi->managed_pslots);
+ xa_for_each(&sbi->managed_pslots, index, pcl) {
+ /* try to shrink each valid pcluster */
+ if (!erofs_try_to_release_pcluster(sbi, pcl))
+ continue;
+ xa_unlock(&sbi->managed_pslots);
+
+ ++freed;
+ if (!--nr)
+ return freed;
+ xa_lock(&sbi->managed_pslots);
+ }
+ xa_unlock(&sbi->managed_pslots);
+ return freed;
+}
+
+static void z_erofs_put_pcluster(struct erofs_sb_info *sbi,
+ struct z_erofs_pcluster *pcl, bool try_free)
+{
+ bool free = false;
+
+ if (lockref_put_or_lock(&pcl->lockref))
+ return;
+
+ DBG_BUGON(lockref_is_dead(&pcl->lockref));
+ if (!--pcl->lockref.count) {
+ if (try_free && xa_trylock(&sbi->managed_pslots)) {
+ free = __erofs_try_to_release_pcluster(sbi, pcl);
+ xa_unlock(&sbi->managed_pslots);
+ }
+ atomic_long_add(!free, &erofs_global_shrink_cnt);
+ }
+ spin_unlock(&pcl->lockref.lock);
+ if (free)
+ call_rcu(&pcl->rcu, z_erofs_rcu_callback);
+}
+
+static void z_erofs_pcluster_end(struct z_erofs_frontend *fe)
+{
+ struct z_erofs_pcluster *pcl = fe->pcl;
+
+ if (!pcl)
+ return;
+
+ z_erofs_bvec_iter_end(&fe->biter);
+ mutex_unlock(&pcl->lock);
+
+ if (fe->candidate_bvpage)
+ fe->candidate_bvpage = NULL;
+
+ /* Drop refcount if it doesn't belong to our processing chain */
+ if (fe->mode < Z_EROFS_PCLUSTER_FOLLOWED_NOINPLACE)
+ z_erofs_put_pcluster(EROFS_I_SB(fe->inode), pcl, false);
+ fe->pcl = NULL;
+}
+
+static int z_erofs_read_fragment(struct super_block *sb, struct folio *folio,
+ unsigned int cur, unsigned int end, erofs_off_t pos)
+{
+ struct inode *packed_inode = EROFS_SB(sb)->packed_inode;
+ struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+ unsigned int cnt;
+ u8 *src;
+
+ if (!packed_inode)
+ return -EFSCORRUPTED;
+
+ buf.mapping = packed_inode->i_mapping;
+ for (; cur < end; cur += cnt, pos += cnt) {
+ cnt = min(end - cur, sb->s_blocksize - erofs_blkoff(sb, pos));
+ src = erofs_bread(&buf, pos, true);
+ if (IS_ERR(src)) {
+ erofs_put_metabuf(&buf);
+ return PTR_ERR(src);
+ }
+ memcpy_to_folio(folio, cur, src, cnt);
+ }
+ erofs_put_metabuf(&buf);
+ return 0;
+}
+
+static int z_erofs_scan_folio(struct z_erofs_frontend *f,
+ struct folio *folio, bool ra)
+{
+ struct inode *const inode = f->inode;
+ struct erofs_map_blocks *const map = &f->map;
+ const loff_t offset = folio_pos(folio);
+ const unsigned int bs = i_blocksize(inode);
+ unsigned int end = folio_size(folio), split = 0, cur, pgs;
+ bool tight, excl;
+ int err = 0;
+
+ tight = (bs == PAGE_SIZE);
+ erofs_onlinefolio_init(folio);
+ do {
+ if (offset + end - 1 < map->m_la ||
+ offset + end - 1 >= map->m_la + map->m_llen) {
+ z_erofs_pcluster_end(f);
+ map->m_la = offset + end - 1;
+ map->m_llen = 0;
+ err = z_erofs_map_blocks_iter(inode, map, 0);
+ if (err)
+ break;
+ }
+
+ cur = offset > map->m_la ? 0 : map->m_la - offset;
+ pgs = round_down(cur, PAGE_SIZE);
+ /* bump split parts first to avoid several separate cases */
+ ++split;
+
+ if (map->m_flags & EROFS_MAP_FRAGMENT) {
+ erofs_off_t fpos = offset + cur - map->m_la;
+
+ err = z_erofs_read_fragment(inode->i_sb, folio, cur,
+ cur + min(map->m_llen - fpos, end - cur),
+ EROFS_I(inode)->z_fragmentoff + fpos);
+ if (err)
+ break;
+ tight = false;
+ } else if (!(map->m_flags & EROFS_MAP_MAPPED)) {
+ folio_zero_segment(folio, cur, end);
+ tight = false;
+ } else {
+ if (!f->pcl) {
+ err = z_erofs_pcluster_begin(f);
+ if (err)
+ break;
+ f->pcl->besteffort |= !ra;
+ }
+
+ pgs = round_down(end - 1, PAGE_SIZE);
+ /*
+ * Ensure this partial page belongs to this submit chain
+ * rather than other concurrent submit chains or
+ * noio(bypass) chains since those chains are handled
+ * asynchronously thus it cannot be used for inplace I/O
+ * or bvpage (should be processed in the strict order.)
+ */
+ tight &= (f->mode >= Z_EROFS_PCLUSTER_FOLLOWED);
+ excl = false;
+ if (cur <= pgs) {
+ excl = (split <= 1) || tight;
+ cur = pgs;
+ }
+
+ err = z_erofs_attach_page(f, &((struct z_erofs_bvec) {
+ .page = folio_page(folio, pgs >> PAGE_SHIFT),
+ .offset = offset + pgs - map->m_la,
+ .end = end - pgs, }), excl);
+ if (err)
+ break;
+
+ erofs_onlinefolio_split(folio);
+ if (f->pcl->length < offset + end - map->m_la) {
+ f->pcl->length = offset + end - map->m_la;
+ f->pcl->pageofs_out = map->m_la & ~PAGE_MASK;
+ }
+ if (EROFS_MAP_FULL(map->m_flags) &&
+ f->pcl->length == map->m_llen)
+ f->pcl->partial = false;
+ }
+ /* shorten the remaining extent to update progress */
+ map->m_llen = offset + cur - map->m_la;
+ map->m_flags |= EROFS_MAP_PARTIAL_MAPPED;
+ if (cur <= pgs) {
+ split = cur < pgs;
+ tight = (bs == PAGE_SIZE);
+ }
+ } while ((end = cur) > 0);
+ erofs_onlinefolio_end(folio, err, false);
+ return err;
+}
+
+static bool z_erofs_page_is_invalidated(struct page *page)
+{
+ return !page_folio(page)->mapping && !z_erofs_is_shortlived_page(page);
+}
+
+struct z_erofs_backend {
+ struct page *onstack_pages[Z_EROFS_ONSTACK_PAGES];
+ struct super_block *sb;
+ struct z_erofs_pcluster *pcl;
+ /* pages with the longest decompressed length for deduplication */
+ struct page **decompressed_pages;
+ /* pages to keep the compressed data */
+ struct page **compressed_pages;
+
+ struct list_head decompressed_secondary_bvecs;
+ struct page **pagepool;
+ unsigned int onstack_used, nr_pages;
+ /* indicate if temporary copies should be preserved for later use */
+ bool keepxcpy;
+};
+
+struct z_erofs_bvec_item {
+ struct z_erofs_bvec bvec;
+ struct list_head list;
+};
+
+static void z_erofs_do_decompressed_bvec(struct z_erofs_backend *be,
+ struct z_erofs_bvec *bvec)
+{
+ int poff = bvec->offset + be->pcl->pageofs_out;
+ struct z_erofs_bvec_item *item;
+ struct page **page;
+
+ if (!(poff & ~PAGE_MASK) && (bvec->end == PAGE_SIZE ||
+ bvec->offset + bvec->end == be->pcl->length)) {
+ DBG_BUGON((poff >> PAGE_SHIFT) >= be->nr_pages);
+ page = be->decompressed_pages + (poff >> PAGE_SHIFT);
+ if (!*page) {
+ *page = bvec->page;
+ return;
+ }
+ } else {
+ be->keepxcpy = true;
+ }
+
+ /* (cold path) one pcluster is requested multiple times */
+ item = kmalloc_obj(*item, GFP_KERNEL | __GFP_NOFAIL);
+ item->bvec = *bvec;
+ list_add(&item->list, &be->decompressed_secondary_bvecs);
+}
+
+static void z_erofs_fill_other_copies(struct z_erofs_backend *be, int err)
+{
+ unsigned int off0 = be->pcl->pageofs_out;
+ struct list_head *p, *n;
+
+ list_for_each_safe(p, n, &be->decompressed_secondary_bvecs) {
+ struct z_erofs_bvec_item *bvi;
+ unsigned int end, cur;
+ void *dst, *src;
+
+ bvi = container_of(p, struct z_erofs_bvec_item, list);
+ cur = bvi->bvec.offset < 0 ? -bvi->bvec.offset : 0;
+ end = min_t(unsigned int, be->pcl->length - bvi->bvec.offset,
+ bvi->bvec.end);
+ dst = kmap_local_page(bvi->bvec.page);
+ while (cur < end) {
+ unsigned int pgnr, scur, len;
+
+ pgnr = (bvi->bvec.offset + cur + off0) >> PAGE_SHIFT;
+ DBG_BUGON(pgnr >= be->nr_pages);
+
+ scur = bvi->bvec.offset + cur -
+ ((pgnr << PAGE_SHIFT) - off0);
+ len = min_t(unsigned int, end - cur, PAGE_SIZE - scur);
+ if (!be->decompressed_pages[pgnr]) {
+ err = -EFSCORRUPTED;
+ cur += len;
+ continue;
+ }
+ src = kmap_local_page(be->decompressed_pages[pgnr]);
+ memcpy(dst + cur, src + scur, len);
+ kunmap_local(src);
+ cur += len;
+ }
+ kunmap_local(dst);
+ erofs_onlinefolio_end(page_folio(bvi->bvec.page), err, true);
+ list_del(p);
+ kfree(bvi);
+ }
+}
+
+static void z_erofs_parse_out_bvecs(struct z_erofs_backend *be)
+{
+ struct z_erofs_pcluster *pcl = be->pcl;
+ struct z_erofs_bvec_iter biter;
+ struct page *old_bvpage;
+ int i;
+
+ z_erofs_bvec_iter_begin(&biter, &pcl->bvset, Z_EROFS_INLINE_BVECS, 0);
+ for (i = 0; i < pcl->vcnt; ++i) {
+ struct z_erofs_bvec bvec;
+
+ z_erofs_bvec_dequeue(&biter, &bvec, &old_bvpage);
+
+ if (old_bvpage)
+ z_erofs_put_shortlivedpage(be->pagepool, old_bvpage);
+
+ DBG_BUGON(z_erofs_page_is_invalidated(bvec.page));
+ z_erofs_do_decompressed_bvec(be, &bvec);
+ }
+
+ old_bvpage = z_erofs_bvec_iter_end(&biter);
+ if (old_bvpage)
+ z_erofs_put_shortlivedpage(be->pagepool, old_bvpage);
+}
+
+static int z_erofs_parse_in_bvecs(struct z_erofs_backend *be, bool *overlapped)
+{
+ struct z_erofs_pcluster *pcl = be->pcl;
+ unsigned int pclusterpages = z_erofs_pclusterpages(pcl);
+ int i, err = 0;
+
+ *overlapped = false;
+ for (i = 0; i < pclusterpages; ++i) {
+ struct z_erofs_bvec *bvec = &pcl->compressed_bvecs[i];
+ struct page *page = bvec->page;
+
+ /* compressed data ought to be valid when decompressing */
+ if (IS_ERR(page) || !page) {
+ bvec->page = NULL; /* clear the failure reason */
+ err = page ? PTR_ERR(page) : -EIO;
+ continue;
+ }
+ be->compressed_pages[i] = page;
+
+ if (pcl->from_meta ||
+ erofs_folio_is_managed(EROFS_SB(be->sb), page_folio(page))) {
+ if (!PageUptodate(page))
+ err = -EIO;
+ continue;
+ }
+
+ DBG_BUGON(z_erofs_page_is_invalidated(page));
+ if (z_erofs_is_shortlived_page(page))
+ continue;
+ z_erofs_do_decompressed_bvec(be, bvec);
+ *overlapped = true;
+ }
+ return err;
+}
+
+static int z_erofs_decompress_pcluster(struct z_erofs_backend *be, bool eio)
+{
+ struct erofs_sb_info *const sbi = EROFS_SB(be->sb);
+ struct z_erofs_pcluster *pcl = be->pcl;
+ unsigned int pclusterpages = z_erofs_pclusterpages(pcl);
+ const struct z_erofs_decompressor *alg =
+ z_erofs_decomp[pcl->algorithmformat];
+ bool try_free = true;
+ int i, j, jtop, err2, err = eio ? -EIO : 0;
+ struct page *page;
+ bool overlapped;
+ const char *reason;
+
+ mutex_lock(&pcl->lock);
+ be->nr_pages = PAGE_ALIGN(pcl->length + pcl->pageofs_out) >> PAGE_SHIFT;
+
+ /* allocate (de)compressed page arrays if cannot be kept on stack */
+ be->decompressed_pages = NULL;
+ be->compressed_pages = NULL;
+ be->onstack_used = 0;
+ if (be->nr_pages <= Z_EROFS_ONSTACK_PAGES) {
+ be->decompressed_pages = be->onstack_pages;
+ be->onstack_used = be->nr_pages;
+ memset(be->decompressed_pages, 0,
+ sizeof(struct page *) * be->nr_pages);
+ }
+
+ if (pclusterpages + be->onstack_used <= Z_EROFS_ONSTACK_PAGES)
+ be->compressed_pages = be->onstack_pages + be->onstack_used;
+
+ if (!be->decompressed_pages)
+ be->decompressed_pages =
+ kvzalloc_objs(struct page *, be->nr_pages,
+ GFP_KERNEL | __GFP_NOFAIL);
+ if (!be->compressed_pages)
+ be->compressed_pages =
+ kvzalloc_objs(struct page *, pclusterpages,
+ GFP_KERNEL | __GFP_NOFAIL);
+
+ z_erofs_parse_out_bvecs(be);
+ err2 = z_erofs_parse_in_bvecs(be, &overlapped);
+ if (err2)
+ err = err2;
+ if (!err) {
+ reason = alg->decompress(&(struct z_erofs_decompress_req) {
+ .sb = be->sb,
+ .in = be->compressed_pages,
+ .out = be->decompressed_pages,
+ .inpages = pclusterpages,
+ .outpages = be->nr_pages,
+ .pageofs_in = pcl->pageofs_in,
+ .pageofs_out = pcl->pageofs_out,
+ .inputsize = pcl->pclustersize,
+ .outputsize = pcl->length,
+ .alg = pcl->algorithmformat,
+ .inplace_io = overlapped,
+ .partial_decoding = pcl->partial,
+ .fillgaps = be->keepxcpy,
+ .gfp = pcl->besteffort ? GFP_KERNEL :
+ GFP_NOWAIT | __GFP_NORETRY
+ }, be->pagepool);
+ if (IS_ERR(reason)) {
+ if (pcl->besteffort || reason != ERR_PTR(-ENOMEM))
+ erofs_err(be->sb, "failed to decompress (%s) %pe @ pa %llu size %u => %u",
+ alg->name, reason, pcl->pos,
+ pcl->pclustersize, pcl->length);
+ err = PTR_ERR(reason);
+ } else if (unlikely(reason)) {
+ erofs_err(be->sb, "failed to decompress (%s) %s @ pa %llu size %u => %u",
+ alg->name, reason, pcl->pos,
+ pcl->pclustersize, pcl->length);
+ err = -EFSCORRUPTED;
+ }
+ }
+
+ /* must handle all compressed pages before actual file pages */
+ if (pcl->from_meta) {
+ folio_put(page_folio(pcl->compressed_bvecs[0].page));
+ WRITE_ONCE(pcl->compressed_bvecs[0].page, NULL);
+ } else {
+ /* managed folios are still left in compressed_bvecs[] */
+ for (i = 0; i < pclusterpages; ++i) {
+ page = be->compressed_pages[i];
+ if (!page)
+ continue;
+ if (erofs_folio_is_managed(sbi, page_folio(page))) {
+ try_free = false;
+ continue;
+ }
+ (void)z_erofs_put_shortlivedpage(be->pagepool, page);
+ WRITE_ONCE(pcl->compressed_bvecs[i].page, NULL);
+ }
+ }
+ if (be->compressed_pages < be->onstack_pages ||
+ be->compressed_pages >= be->onstack_pages + Z_EROFS_ONSTACK_PAGES)
+ kvfree(be->compressed_pages);
+
+ jtop = 0;
+ z_erofs_fill_other_copies(be, err);
+ for (i = 0; i < be->nr_pages; ++i) {
+ page = be->decompressed_pages[i];
+ if (!page)
+ continue;
+
+ DBG_BUGON(z_erofs_page_is_invalidated(page));
+ if (!z_erofs_is_shortlived_page(page)) {
+ erofs_onlinefolio_end(page_folio(page), err, true);
+ continue;
+ }
+ if (pcl->algorithmformat != Z_EROFS_COMPRESSION_LZ4) {
+ erofs_pagepool_add(be->pagepool, page);
+ continue;
+ }
+ for (j = 0; j < jtop && be->decompressed_pages[j] != page; ++j)
+ ;
+ if (j >= jtop) /* this bounce page is newly detected */
+ be->decompressed_pages[jtop++] = page;
+ }
+ while (jtop)
+ erofs_pagepool_add(be->pagepool,
+ be->decompressed_pages[--jtop]);
+ if (be->decompressed_pages != be->onstack_pages)
+ kvfree(be->decompressed_pages);
+
+ pcl->length = 0;
+ pcl->partial = true;
+ pcl->besteffort = false;
+ pcl->bvset.nextpage = NULL;
+ pcl->vcnt = 0;
+
+ /* pcluster lock MUST be taken before the following line */
+ WRITE_ONCE(pcl->next, NULL);
+ mutex_unlock(&pcl->lock);
+
+ if (pcl->from_meta)
+ z_erofs_free_pcluster(pcl);
+ else
+ z_erofs_put_pcluster(sbi, pcl, try_free);
+ return err;
+}
+
+static int z_erofs_decompress_queue(const struct z_erofs_decompressqueue *io,
+ struct page **pagepool)
+{
+ struct z_erofs_backend be = {
+ .sb = io->sb,
+ .pagepool = pagepool,
+ .decompressed_secondary_bvecs =
+ LIST_HEAD_INIT(be.decompressed_secondary_bvecs),
+ .pcl = io->head,
+ };
+ struct z_erofs_pcluster *next;
+ int err = 0;
+
+ for (; be.pcl != Z_EROFS_PCLUSTER_TAIL; be.pcl = next) {
+ DBG_BUGON(!be.pcl);
+ next = READ_ONCE(be.pcl->next);
+ err = z_erofs_decompress_pcluster(&be, io->eio) ?: err;
+ }
+ return err;
+}
+
+static void z_erofs_decompressqueue_work(struct work_struct *work)
+{
+ struct z_erofs_decompressqueue *bgq =
+ container_of(work, struct z_erofs_decompressqueue, u.work);
+ struct page *pagepool = NULL;
+
+ DBG_BUGON(bgq->head == Z_EROFS_PCLUSTER_TAIL);
+ z_erofs_decompress_queue(bgq, &pagepool);
+ erofs_release_pages(&pagepool);
+ kvfree(bgq);
+}
+
+#ifdef CONFIG_EROFS_FS_PCPU_KTHREAD
+static void z_erofs_decompressqueue_kthread_work(struct kthread_work *work)
+{
+ z_erofs_decompressqueue_work((struct work_struct *)work);
+}
+#endif
+
+
+static void z_erofs_decompress_kickoff(struct z_erofs_decompressqueue *io,
+ int bios)
+{
+ struct erofs_sb_info *const sbi = EROFS_SB(io->sb);
+ int gfp_flag;
+
+ /* wake up the caller thread for sync decompression */
+ if (io->sync) {
+ if (!atomic_add_return(bios, &io->pending_bios))
+ complete(&io->u.done);
+ return;
+ }
+
+ if (atomic_add_return(bios, &io->pending_bios))
+ return;
+ if (bio_in_atomic()) {
+ /* See `sync_decompress` in sysfs-fs-erofs for more details */
+ if (sbi->sync_decompress == EROFS_SYNC_DECOMPRESS_AUTO)
+ sbi->sync_decompress = EROFS_SYNC_DECOMPRESS_FORCE_ON;
+#ifdef CONFIG_EROFS_FS_PCPU_KTHREAD
+ scoped_guard(rcu) {
+ struct kthread_worker *worker;
+
+ worker = rcu_dereference(
+ z_erofs_pcpu_workers[raw_smp_processor_id()]);
+ if (worker) {
+ kthread_queue_work(worker, &io->u.kthread_work);
+ return;
+ }
+ }
+ INIT_WORK(&io->u.work, z_erofs_decompressqueue_work);
+#endif
+ queue_work(z_erofs_workqueue, &io->u.work);
+ return;
+ }
+ gfp_flag = memalloc_noio_save();
+ z_erofs_decompressqueue_work(&io->u.work);
+ memalloc_noio_restore(gfp_flag);
+}
+
+static void z_erofs_fill_bio_vec(struct bio_vec *bvec,
+ struct z_erofs_frontend *f,
+ struct z_erofs_pcluster *pcl,
+ unsigned int nr,
+ struct address_space *mc)
+{
+ gfp_t gfp = mapping_gfp_mask(mc);
+ bool tocache = false;
+ struct z_erofs_bvec zbv;
+ struct address_space *mapping;
+ struct folio *folio;
+ struct page *page;
+ int bs = i_blocksize(f->inode);
+
+ /* Except for inplace folios, the entire folio can be used for I/Os */
+ bvec->bv_offset = 0;
+ bvec->bv_len = PAGE_SIZE;
+repeat:
+ spin_lock(&pcl->lockref.lock);
+ zbv = pcl->compressed_bvecs[nr];
+ spin_unlock(&pcl->lockref.lock);
+ if (!zbv.page)
+ goto out_allocfolio;
+
+ bvec->bv_page = zbv.page;
+ DBG_BUGON(z_erofs_is_shortlived_page(bvec->bv_page));
+
+ folio = page_folio(zbv.page);
+ /*
+ * Preallocated folios are added to the managed cache here rather than
+ * in z_erofs_bind_cache() in order to keep these folios locked in
+ * increasing (physical) address order.
+ * Clear folio->private before these folios become visible to others in
+ * the managed cache to avoid duplicate additions for unaligned extents.
+ */
+ if (folio->private == Z_EROFS_PREALLOCATED_FOLIO) {
+ folio->private = NULL;
+ tocache = true;
+ goto out_tocache;
+ }
+
+ mapping = READ_ONCE(folio->mapping);
+ /*
+ * File-backed folios for inplace I/Os are all locked steady,
+ * therefore it is impossible for `mapping` to be NULL.
+ */
+ if (mapping && mapping != mc) {
+ if (zbv.offset < 0)
+ bvec->bv_offset = round_up(-zbv.offset, bs);
+ bvec->bv_len = round_up(zbv.end, bs) - bvec->bv_offset;
+ return;
+ }
+
+ folio_lock(folio);
+ if (likely(folio->mapping == mc)) {
+ /*
+ * The cached folio is still in managed cache but without
+ * a valid `->private` pcluster hint. Let's reconnect them.
+ */
+ if (!folio_test_private(folio)) {
+ folio_attach_private(folio, pcl);
+ /* compressed_bvecs[] already takes a ref before */
+ folio_put(folio);
+ }
+ if (likely(folio->private == pcl)) {
+ /* don't submit cache I/Os again if already uptodate */
+ if (folio_test_uptodate(folio)) {
+ folio_unlock(folio);
+ bvec->bv_page = NULL;
+ }
+ return;
+ }
+ } else {
+ DBG_BUGON(1); /* referenced managed folios can't be truncated */
+ }
+ folio_unlock(folio);
+ folio_put(folio);
+out_allocfolio:
+ page = __erofs_allocpage(&f->pagepool, gfp, true);
+ spin_lock(&pcl->lockref.lock);
+ if (unlikely(pcl->compressed_bvecs[nr].page != zbv.page)) {
+ if (page)
+ erofs_pagepool_add(&f->pagepool, page);
+ spin_unlock(&pcl->lockref.lock);
+ cond_resched();
+ goto repeat;
+ }
+ pcl->compressed_bvecs[nr].page = page ? page : ERR_PTR(-ENOMEM);
+ spin_unlock(&pcl->lockref.lock);
+ bvec->bv_page = page;
+ if (!page)
+ return;
+ folio = page_folio(page);
+out_tocache:
+ if (!tocache || bs != PAGE_SIZE ||
+ filemap_add_folio(mc, folio, (pcl->pos >> PAGE_SHIFT) + nr, gfp)) {
+ /* turn into a temporary shortlived folio (1 ref) */
+ folio->private = (void *)Z_EROFS_SHORTLIVED_PAGE;
+ return;
+ }
+ folio_attach_private(folio, pcl);
+ /* drop a refcount added by allocpage (then 2 refs in total here) */
+ folio_put(folio);
+}
+
+static struct z_erofs_decompressqueue *jobqueue_init(struct super_block *sb,
+ struct z_erofs_decompressqueue *fgq, bool *fg)
+{
+ struct z_erofs_decompressqueue *q;
+
+ if (fg && !*fg) {
+ q = kvzalloc_obj(*q, GFP_KERNEL | __GFP_NOWARN);
+ if (!q) {
+ *fg = true;
+ goto fg_out;
+ }
+#ifdef CONFIG_EROFS_FS_PCPU_KTHREAD
+ kthread_init_work(&q->u.kthread_work,
+ z_erofs_decompressqueue_kthread_work);
+#else
+ INIT_WORK(&q->u.work, z_erofs_decompressqueue_work);
+#endif
+ } else {
+fg_out:
+ q = fgq;
+ init_completion(&fgq->u.done);
+ atomic_set(&fgq->pending_bios, 0);
+ q->eio = false;
+ q->sync = true;
+ }
+ q->sb = sb;
+ q->head = Z_EROFS_PCLUSTER_TAIL;
+ return q;
+}
+
+/* define decompression jobqueue types */
+enum {
+ JQ_BYPASS,
+ JQ_SUBMIT,
+ NR_JOBQUEUES,
+};
+
+static void z_erofs_move_to_bypass_queue(struct z_erofs_pcluster *pcl,
+ struct z_erofs_pcluster *next,
+ struct z_erofs_pcluster **qtail[])
+{
+ WRITE_ONCE(pcl->next, Z_EROFS_PCLUSTER_TAIL);
+ WRITE_ONCE(*qtail[JQ_SUBMIT], next);
+ WRITE_ONCE(*qtail[JQ_BYPASS], pcl);
+ qtail[JQ_BYPASS] = &pcl->next;
+}
+
+static void z_erofs_endio(struct bio *bio)
+{
+ struct z_erofs_decompressqueue *q = bio->bi_private;
+ blk_status_t err = bio->bi_status;
+ struct folio_iter fi;
+
+ bio_for_each_folio_all(fi, bio) {
+ struct folio *folio = fi.folio;
+
+ DBG_BUGON(folio_test_uptodate(folio));
+ DBG_BUGON(z_erofs_page_is_invalidated(&folio->page));
+ if (!erofs_folio_is_managed(EROFS_SB(q->sb), folio))
+ continue;
+
+ if (!err)
+ folio_mark_uptodate(folio);
+ folio_unlock(folio);
+ }
+ if (err)
+ q->eio = true;
+ z_erofs_decompress_kickoff(q, -1);
+ if (bio->bi_bdev)
+ bio_put(bio);
+}
+
+static void z_erofs_submit_queue(struct z_erofs_frontend *f,
+ struct z_erofs_decompressqueue *fgq,
+ bool *force_fg, bool readahead)
+{
+ struct super_block *sb = f->inode->i_sb;
+ struct address_space *mc = MNGD_MAPPING(EROFS_SB(sb));
+ struct z_erofs_pcluster **qtail[NR_JOBQUEUES];
+ struct z_erofs_decompressqueue *q[NR_JOBQUEUES];
+ struct z_erofs_pcluster *pcl, *next;
+ /* bio is NULL initially, so no need to initialize last_{index,bdev} */
+ erofs_off_t last_pa;
+ unsigned int nr_bios = 0;
+ struct bio *bio = NULL;
+ unsigned long pflags;
+ int memstall = 0;
+
+ /* No need to read from device for pclusters in the bypass queue. */
+ q[JQ_BYPASS] = jobqueue_init(sb, fgq + JQ_BYPASS, NULL);
+ q[JQ_SUBMIT] = jobqueue_init(sb, fgq + JQ_SUBMIT, force_fg);
+
+ qtail[JQ_BYPASS] = &q[JQ_BYPASS]->head;
+ qtail[JQ_SUBMIT] = &q[JQ_SUBMIT]->head;
+
+ /* by default, all need io submission */
+ q[JQ_SUBMIT]->head = next = f->head;
+
+ do {
+ struct erofs_map_dev mdev;
+ erofs_off_t cur, end;
+ struct bio_vec bvec;
+ unsigned int i = 0;
+ bool bypass = true;
+
+ pcl = next;
+ next = READ_ONCE(pcl->next);
+ if (pcl->from_meta) {
+ z_erofs_move_to_bypass_queue(pcl, next, qtail);
+ continue;
+ }
+
+ /* no device id here, thus it will always succeed */
+ mdev = (struct erofs_map_dev) {
+ .m_pa = round_down(pcl->pos, sb->s_blocksize),
+ };
+ (void)erofs_map_dev(sb, &mdev);
+
+ cur = mdev.m_pa;
+ end = round_up(cur + pcl->pageofs_in + pcl->pclustersize,
+ sb->s_blocksize);
+ do {
+ bvec.bv_page = NULL;
+ if (bio && (cur != last_pa ||
+ bio->bi_bdev != mdev.m_bdev)) {
+drain_io:
+ if (erofs_is_fileio_mode(EROFS_SB(sb)))
+ erofs_fileio_submit_bio(bio);
+ else
+ submit_bio(bio);
+
+ if (memstall) {
+ psi_memstall_leave(&pflags);
+ memstall = 0;
+ }
+ bio = NULL;
+ }
+
+ if (!bvec.bv_page) {
+ z_erofs_fill_bio_vec(&bvec, f, pcl, i++, mc);
+ if (!bvec.bv_page)
+ continue;
+ if (cur + bvec.bv_len > end)
+ bvec.bv_len = end - cur;
+ DBG_BUGON(bvec.bv_len < sb->s_blocksize);
+ }
+
+ if (unlikely(PageWorkingset(bvec.bv_page)) &&
+ !memstall) {
+ psi_memstall_enter(&pflags);
+ memstall = 1;
+ }
+
+ if (!bio) {
+ if (erofs_is_fileio_mode(EROFS_SB(sb)))
+ bio = erofs_fileio_bio_alloc(&mdev);
+ else
+ bio = bio_alloc(mdev.m_bdev, BIO_MAX_VECS,
+ REQ_OP_READ, GFP_NOIO);
+ bio->bi_end_io = z_erofs_endio;
+ bio->bi_iter.bi_sector =
+ (mdev.m_dif->fsoff + cur) >> 9;
+ bio->bi_private = q[JQ_SUBMIT];
+ if (readahead)
+ bio->bi_opf |= REQ_RAHEAD;
+ ++nr_bios;
+ }
+
+ if (!bio_add_page(bio, bvec.bv_page, bvec.bv_len,
+ bvec.bv_offset))
+ goto drain_io;
+ last_pa = cur + bvec.bv_len;
+ bypass = false;
+ } while ((cur += bvec.bv_len) < end);
+
+ if (!bypass)
+ qtail[JQ_SUBMIT] = &pcl->next;
+ else
+ z_erofs_move_to_bypass_queue(pcl, next, qtail);
+ } while (next != Z_EROFS_PCLUSTER_TAIL);
+
+ if (bio) {
+ if (erofs_is_fileio_mode(EROFS_SB(sb)))
+ erofs_fileio_submit_bio(bio);
+ else
+ submit_bio(bio);
+ }
+ if (memstall)
+ psi_memstall_leave(&pflags);
+
+ /*
+ * although background is preferred, no one is pending for submission.
+ * don't issue decompression but drop it directly instead.
+ */
+ if (!*force_fg && !nr_bios) {
+ kvfree(q[JQ_SUBMIT]);
+ return;
+ }
+ z_erofs_decompress_kickoff(q[JQ_SUBMIT], nr_bios);
+}
+
+static int z_erofs_runqueue(struct z_erofs_frontend *f, unsigned int rabytes)
+{
+ struct z_erofs_decompressqueue io[NR_JOBQUEUES];
+ struct erofs_sb_info *sbi = EROFS_I_SB(f->inode);
+ int syncmode = sbi->sync_decompress;
+ bool force_fg;
+ int err;
+
+ force_fg = (syncmode == EROFS_SYNC_DECOMPRESS_AUTO && !rabytes) ||
+ (syncmode == EROFS_SYNC_DECOMPRESS_FORCE_ON &&
+ (rabytes <= Z_EROFS_MAX_SYNC_DECOMPRESS_BYTES));
+
+ if (f->head == Z_EROFS_PCLUSTER_TAIL)
+ return 0;
+ z_erofs_submit_queue(f, io, &force_fg, !!rabytes);
+
+ /* handle bypass queue (no i/o pclusters) immediately */
+ err = z_erofs_decompress_queue(&io[JQ_BYPASS], &f->pagepool);
+ if (!force_fg)
+ return err;
+
+ /* wait until all bios are completed */
+ wait_for_completion_io(&io[JQ_SUBMIT].u.done);
+
+ /* handle synchronous decompress queue in the caller context */
+ return z_erofs_decompress_queue(&io[JQ_SUBMIT], &f->pagepool) ?: err;
+}
+
+/*
+ * Since partial uptodate is still unimplemented for now, we have to use
+ * approximate readmore strategies as a start.
+ */
+static void z_erofs_pcluster_readmore(struct z_erofs_frontend *f,
+ struct readahead_control *rac, bool backmost)
+{
+ struct inode *inode = f->inode;
+ struct erofs_map_blocks *map = &f->map;
+ erofs_off_t cur, end, headoffset = f->headoffset;
+ int err;
+
+ if (backmost) {
+ if (rac)
+ end = headoffset + readahead_length(rac) - 1;
+ else
+ end = headoffset + PAGE_SIZE - 1;
+ map->m_la = end;
+ err = z_erofs_map_blocks_iter(inode, map,
+ EROFS_GET_BLOCKS_READMORE);
+ if (err || !(map->m_flags & EROFS_MAP_MAPPED))
+ return;
+
+ /* expand ra for the trailing edge if readahead */
+ if (rac) {
+ cur = round_up(map->m_la + map->m_llen, PAGE_SIZE);
+ readahead_expand(rac, headoffset, cur - headoffset);
+ return;
+ }
+ end = round_up(end, PAGE_SIZE);
+ } else {
+ end = round_up(map->m_la, PAGE_SIZE);
+ if (!(map->m_flags & EROFS_MAP_MAPPED) || !map->m_llen)
+ return;
+ }
+
+ cur = map->m_la + map->m_llen - 1;
+ while ((cur >= end) && (cur < i_size_read(inode))) {
+ pgoff_t index = cur >> PAGE_SHIFT;
+ struct folio *folio;
+
+ folio = erofs_grab_folio_nowait(f->sharedinode->i_mapping, index);
+ if (!IS_ERR_OR_NULL(folio)) {
+ if (folio_test_uptodate(folio))
+ folio_unlock(folio);
+ else
+ z_erofs_scan_folio(f, folio, !!rac);
+ folio_put(folio);
+ }
+
+ if (cur < PAGE_SIZE)
+ break;
+ cur = ((loff_t)index << PAGE_SHIFT) - 1;
+ }
+}
+
+static int z_erofs_read_folio(struct file *file, struct folio *folio)
+{
+ struct inode *sharedinode = folio->mapping->host;
+ bool need_iput;
+ struct inode *realinode = erofs_real_inode(sharedinode, &need_iput);
+ Z_EROFS_DEFINE_FRONTEND(f, realinode, sharedinode, folio_pos(folio));
+ int err;
+
+ trace_erofs_read_folio(realinode, folio, false);
+ z_erofs_pcluster_readmore(&f, NULL, true);
+ err = z_erofs_scan_folio(&f, folio, false);
+ z_erofs_pcluster_readmore(&f, NULL, false);
+ z_erofs_pcluster_end(&f);
+
+ /* if some pclusters are ready, need submit them anyway */
+ err = z_erofs_runqueue(&f, 0) ?: err;
+ if (err && err != -EINTR)
+ erofs_err(realinode->i_sb, "read error %d @ %lu of nid %llu",
+ err, folio->index, EROFS_I(realinode)->nid);
+
+ erofs_put_metabuf(&f.map.buf);
+ erofs_release_pages(&f.pagepool);
+
+ if (need_iput)
+ iput(realinode);
+ return err;
+}
+
+static void z_erofs_readahead(struct readahead_control *rac)
+{
+ struct inode *sharedinode = rac->mapping->host;
+ bool need_iput;
+ struct inode *realinode = erofs_real_inode(sharedinode, &need_iput);
+ Z_EROFS_DEFINE_FRONTEND(f, realinode, sharedinode, readahead_pos(rac));
+ unsigned int nrpages = readahead_count(rac);
+ struct folio *head = NULL, *folio;
+ int err;
+
+ trace_erofs_readahead(realinode, readahead_index(rac), nrpages, false);
+ z_erofs_pcluster_readmore(&f, rac, true);
+ while ((folio = readahead_folio(rac))) {
+ folio->private = head;
+ head = folio;
+ }
+
+ /* traverse in reverse order for best metadata I/O performance */
+ while (head) {
+ folio = head;
+ head = folio_get_private(folio);
+
+ err = z_erofs_scan_folio(&f, folio, true);
+ if (err && err != -EINTR)
+ erofs_err(realinode->i_sb, "readahead error at folio %lu @ nid %llu",
+ folio->index, EROFS_I(realinode)->nid);
+ }
+ z_erofs_pcluster_readmore(&f, rac, false);
+ z_erofs_pcluster_end(&f);
+
+ (void)z_erofs_runqueue(&f, nrpages << PAGE_SHIFT);
+ erofs_put_metabuf(&f.map.buf);
+ erofs_release_pages(&f.pagepool);
+
+ if (need_iput)
+ iput(realinode);
+}
+
+const struct address_space_operations z_erofs_aops = {
+ .read_folio = z_erofs_read_folio,
+ .readahead = z_erofs_readahead,
+};
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
new file mode 100644
index 000000000..f8981fc74
--- /dev/null
+++ b/fs/erofs/zmap.c
@@ -0,0 +1,838 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2018-2019 HUAWEI, Inc.
+ * https://www.huawei.com/
+ */
+#include "internal.h"
+#include <linux/unaligned.h>
+#include <trace/events/erofs.h>
+
+struct z_erofs_maprecorder {
+ struct inode *inode;
+ struct erofs_map_blocks *map;
+ u64 lcn;
+ /* compression extent information gathered */
+ u8 type, headtype;
+ u16 clusterofs;
+ u16 delta[2];
+ erofs_blk_t pblk;
+ erofs_off_t nextpackoff;
+ int compressedblks;
+ bool partialref, in_mbox;
+};
+
+static int z_erofs_load_full_lcluster(struct z_erofs_maprecorder *m, u64 lcn)
+{
+ struct inode *const inode = m->inode;
+ struct erofs_inode *const vi = EROFS_I(inode);
+ const erofs_off_t pos = Z_EROFS_FULL_INDEX_START(erofs_iloc(inode) +
+ vi->inode_isize + vi->xattr_isize) +
+ lcn * sizeof(struct z_erofs_lcluster_index);
+ struct z_erofs_lcluster_index *di;
+ unsigned int advise;
+
+ di = erofs_read_metabuf(&m->map->buf, inode->i_sb, pos, m->in_mbox);
+ if (IS_ERR(di))
+ return PTR_ERR(di);
+ m->lcn = lcn;
+ m->nextpackoff = pos + sizeof(struct z_erofs_lcluster_index);
+
+ advise = le16_to_cpu(di->di_advise);
+ m->type = advise & Z_EROFS_LI_LCLUSTER_TYPE_MASK;
+ if (m->type == Z_EROFS_LCLUSTER_TYPE_NONHEAD) {
+ m->clusterofs = 1 << vi->z_lclusterbits;
+ m->delta[0] = le16_to_cpu(di->di_u.delta[0]);
+ if (m->delta[0] & Z_EROFS_LI_D0_CBLKCNT) {
+ if (!(vi->z_advise & (Z_EROFS_ADVISE_BIG_PCLUSTER_1 |
+ Z_EROFS_ADVISE_BIG_PCLUSTER_2))) {
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
+ m->compressedblks = m->delta[0] & ~Z_EROFS_LI_D0_CBLKCNT;
+ m->delta[0] = 1;
+ }
+ m->delta[1] = le16_to_cpu(di->di_u.delta[1]);
+ } else {
+ m->partialref = !!(advise & Z_EROFS_LI_PARTIAL_REF);
+ m->clusterofs = le16_to_cpu(di->di_clusterofs);
+ if (advise & Z_EROFS_LI_HOLE) {
+ m->compressedblks = 0;
+ m->pblk = EROFS_NULL_ADDR;
+ } else {
+ m->pblk = le32_to_cpu(di->di_u.blkaddr);
+ }
+ }
+ return 0;
+}
+
+static unsigned int decode_compactedbits(unsigned int lobits,
+ u8 *in, unsigned int pos, u8 *type)
+{
+ const unsigned int v = get_unaligned_le32(in + pos / 8) >> (pos & 7);
+ const unsigned int lo = v & ((1 << lobits) - 1);
+
+ *type = (v >> lobits) & 3;
+ return lo;
+}
+
+static int get_compacted_la_distance(unsigned int lobits,
+ unsigned int encodebits,
+ unsigned int vcnt, u8 *in, int i)
+{
+ unsigned int lo, d1 = 0;
+ u8 type;
+
+ DBG_BUGON(i >= vcnt);
+
+ do {
+ lo = decode_compactedbits(lobits, in, encodebits * i, &type);
+
+ if (type != Z_EROFS_LCLUSTER_TYPE_NONHEAD)
+ return d1;
+ ++d1;
+ } while (++i < vcnt);
+
+ /* vcnt - 1 (Z_EROFS_LCLUSTER_TYPE_NONHEAD) item */
+ if (!(lo & Z_EROFS_LI_D0_CBLKCNT))
+ d1 += lo - 1;
+ return d1;
+}
+
+static int z_erofs_load_compact_lcluster(struct z_erofs_maprecorder *m,
+ u64 lcn, bool lookahead)
+{
+ struct inode *const inode = m->inode;
+ struct erofs_inode *const vi = EROFS_I(inode);
+ const erofs_off_t ebase = Z_EROFS_MAP_HEADER_END(erofs_iloc(inode) +
+ vi->inode_isize + vi->xattr_isize);
+ const unsigned int lclusterbits = vi->z_lclusterbits;
+ const unsigned int totalidx = erofs_iblks(inode);
+ unsigned int compacted_4b_initial, compacted_2b, amortizedshift;
+ unsigned int vcnt, lo, lobits, encodebits, nblk, bytes;
+ bool big_pcluster = vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1;
+ erofs_off_t pos;
+ u8 *in, type;
+ int i;
+
+ if (lcn >= totalidx || lclusterbits > 14)
+ return -EINVAL;
+
+ m->lcn = lcn;
+ /* used to align to 32-byte (compacted_2b) alignment */
+ compacted_4b_initial = ((32 - ebase % 32) / 4) & 7;
+ compacted_2b = 0;
+ if ((vi->z_advise & Z_EROFS_ADVISE_COMPACTED_2B) &&
+ compacted_4b_initial < totalidx)
+ compacted_2b = rounddown(totalidx - compacted_4b_initial, 16);
+
+ pos = ebase;
+ amortizedshift = 2; /* compact_4b */
+ if (lcn >= compacted_4b_initial) {
+ pos += compacted_4b_initial * 4;
+ lcn -= compacted_4b_initial;
+ if (lcn < compacted_2b) {
+ amortizedshift = 1;
+ } else {
+ pos += compacted_2b * 2;
+ lcn -= compacted_2b;
+ }
+ }
+ pos += lcn * (1 << amortizedshift);
+
+ /* figure out the lcluster count in this pack */
+ if (1 << amortizedshift == 4 && lclusterbits <= 14)
+ vcnt = 2;
+ else if (1 << amortizedshift == 2 && lclusterbits <= 12)
+ vcnt = 16;
+ else
+ return -EOPNOTSUPP;
+
+ in = erofs_read_metabuf(&m->map->buf, inode->i_sb, pos, m->in_mbox);
+ if (IS_ERR(in))
+ return PTR_ERR(in);
+
+ /* it doesn't equal to round_up(..) */
+ m->nextpackoff = round_down(pos, vcnt << amortizedshift) +
+ (vcnt << amortizedshift);
+ lobits = max(lclusterbits, ilog2(Z_EROFS_LI_D0_CBLKCNT) + 1U);
+ encodebits = ((vcnt << amortizedshift) - sizeof(__le32)) * 8 / vcnt;
+ bytes = pos & ((vcnt << amortizedshift) - 1);
+ in -= bytes;
+ i = bytes >> amortizedshift;
+
+ lo = decode_compactedbits(lobits, in, encodebits * i, &type);
+ m->type = type;
+ if (type == Z_EROFS_LCLUSTER_TYPE_NONHEAD) {
+ m->clusterofs = 1 << lclusterbits;
+
+ /* figure out lookahead_distance: delta[1] if needed */
+ if (lookahead)
+ m->delta[1] = get_compacted_la_distance(lobits,
+ encodebits, vcnt, in, i);
+ if (lo & Z_EROFS_LI_D0_CBLKCNT) {
+ if (!big_pcluster) {
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
+ m->compressedblks = lo & ~Z_EROFS_LI_D0_CBLKCNT;
+ m->delta[0] = 1;
+ return 0;
+ } else if (i + 1 != (int)vcnt) {
+ m->delta[0] = lo;
+ return 0;
+ }
+ /*
+ * since the last lcluster in the pack is special,
+ * of which lo saves delta[1] rather than delta[0].
+ * Hence, get delta[0] by the previous lcluster indirectly.
+ */
+ lo = decode_compactedbits(lobits, in,
+ encodebits * (i - 1), &type);
+ if (type != Z_EROFS_LCLUSTER_TYPE_NONHEAD)
+ lo = 0;
+ else if (lo & Z_EROFS_LI_D0_CBLKCNT)
+ lo = 1;
+ m->delta[0] = lo + 1;
+ return 0;
+ }
+ m->clusterofs = lo;
+ m->delta[0] = 0;
+ /* figout out blkaddr (pblk) for HEAD lclusters */
+ if (!big_pcluster) {
+ nblk = 1;
+ while (i > 0) {
+ --i;
+ lo = decode_compactedbits(lobits, in,
+ encodebits * i, &type);
+ if (type == Z_EROFS_LCLUSTER_TYPE_NONHEAD)
+ i -= lo;
+
+ if (i >= 0)
+ ++nblk;
+ }
+ } else {
+ nblk = 0;
+ while (i > 0) {
+ --i;
+ lo = decode_compactedbits(lobits, in,
+ encodebits * i, &type);
+ if (type == Z_EROFS_LCLUSTER_TYPE_NONHEAD) {
+ if (lo & Z_EROFS_LI_D0_CBLKCNT) {
+ --i;
+ nblk += lo & ~Z_EROFS_LI_D0_CBLKCNT;
+ continue;
+ }
+ /* bigpcluster shouldn't have plain d0 == 1 */
+ if (lo <= 1) {
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
+ i -= lo - 2;
+ continue;
+ }
+ ++nblk;
+ }
+ }
+ in += (vcnt << amortizedshift) - sizeof(__le32);
+ m->pblk = le32_to_cpu(*(__le32 *)in) + nblk;
+ return 0;
+}
+
+static int z_erofs_load_lcluster_from_disk(struct z_erofs_maprecorder *m,
+ u64 lcn, bool lookahead)
+{
+ struct erofs_inode *vi = EROFS_I(m->inode);
+ int err;
+
+ if (vi->datalayout == EROFS_INODE_COMPRESSED_COMPACT) {
+ err = z_erofs_load_compact_lcluster(m, lcn, lookahead);
+ } else {
+ DBG_BUGON(vi->datalayout != EROFS_INODE_COMPRESSED_FULL);
+ err = z_erofs_load_full_lcluster(m, lcn);
+ }
+ if (err)
+ return err;
+
+ if (m->type >= Z_EROFS_LCLUSTER_TYPE_MAX) {
+ erofs_err(m->inode->i_sb, "unknown type %u @ lcn %llu of nid %llu",
+ m->type, lcn, EROFS_I(m->inode)->nid);
+ DBG_BUGON(1);
+ return -EOPNOTSUPP;
+ } else if (m->type != Z_EROFS_LCLUSTER_TYPE_NONHEAD &&
+ m->clusterofs >= (1 << vi->z_lclusterbits)) {
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
+ return 0;
+}
+
+static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
+ unsigned int lookback_distance)
+{
+ struct super_block *sb = m->inode->i_sb;
+ struct erofs_inode *const vi = EROFS_I(m->inode);
+ const unsigned int lclusterbits = vi->z_lclusterbits;
+
+ while (m->lcn >= lookback_distance) {
+ u64 lcn = m->lcn - lookback_distance;
+ int err;
+
+ if (!lookback_distance)
+ break;
+
+ err = z_erofs_load_lcluster_from_disk(m, lcn, false);
+ if (err)
+ return err;
+ if (m->type == Z_EROFS_LCLUSTER_TYPE_NONHEAD) {
+ lookback_distance = m->delta[0];
+ continue;
+ }
+ m->headtype = m->type;
+ m->map->m_la = (lcn << lclusterbits) | m->clusterofs;
+ return 0;
+ }
+ erofs_err(sb, "bogus lookback distance %u @ lcn %llu of nid %llu",
+ lookback_distance, m->lcn, vi->nid);
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+}
+
+static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
+ unsigned int initial_lcn)
+{
+ struct inode *inode = m->inode;
+ struct super_block *sb = inode->i_sb;
+ struct erofs_inode *vi = EROFS_I(inode);
+ bool bigpcl1 = vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1;
+ bool bigpcl2 = vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_2;
+ u64 lcn = m->lcn + 1;
+ int err;
+
+ DBG_BUGON(m->type == Z_EROFS_LCLUSTER_TYPE_NONHEAD);
+ DBG_BUGON(m->type != m->headtype);
+
+ if ((m->headtype == Z_EROFS_LCLUSTER_TYPE_HEAD1 && !bigpcl1) ||
+ ((m->headtype == Z_EROFS_LCLUSTER_TYPE_PLAIN ||
+ m->headtype == Z_EROFS_LCLUSTER_TYPE_HEAD2) && !bigpcl2) ||
+ (lcn << vi->z_lclusterbits) >= inode->i_size)
+ if (m->compressedblks < 0)
+ m->compressedblks = 1;
+
+ if (m->compressedblks >= 0)
+ goto out;
+
+ err = z_erofs_load_lcluster_from_disk(m, lcn, false);
+ if (err)
+ return err;
+
+ /*
+ * If the 1st NONHEAD lcluster has already been handled initially w/o
+ * valid compressedblks, which means at least it mustn't be CBLKCNT, or
+ * an internal implemenatation error is detected.
+ *
+ * The following code can also handle it properly anyway, but let's
+ * BUG_ON in the debugging mode only for developers to notice that.
+ */
+ DBG_BUGON(lcn == initial_lcn &&
+ m->type == Z_EROFS_LCLUSTER_TYPE_NONHEAD);
+
+ if (m->type != Z_EROFS_LCLUSTER_TYPE_NONHEAD) {
+ /*
+ * if the 1st NONHEAD lcluster is actually PLAIN or HEAD type
+ * rather than CBLKCNT, it's a 1 block-sized pcluster.
+ */
+ if (m->compressedblks < 0)
+ m->compressedblks = 1;
+ } else if (m->delta[0] != 1 || m->compressedblks < 0) {
+ erofs_err(sb, "bogus CBLKCNT @ lcn %llu of nid %llu", lcn, vi->nid);
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
+
+out:
+ if (!m->compressedblks)
+ m->map->m_flags &= ~EROFS_MAP_MAPPED;
+ m->map->m_plen = erofs_pos(sb, m->compressedblks);
+ return 0;
+}
+
+static int z_erofs_get_extent_decompressedlen(struct z_erofs_maprecorder *m)
+{
+ struct inode *inode = m->inode;
+ struct erofs_inode *vi = EROFS_I(inode);
+ struct erofs_map_blocks *map = m->map;
+ unsigned int lclusterbits = vi->z_lclusterbits;
+ u64 lcn = m->lcn, headlcn = map->m_la >> lclusterbits;
+ int err;
+
+ while (1) {
+ /* handle the last EOF pcluster (no next HEAD lcluster) */
+ if ((lcn << lclusterbits) >= inode->i_size) {
+ map->m_llen = inode->i_size - map->m_la;
+ return 0;
+ }
+
+ err = z_erofs_load_lcluster_from_disk(m, lcn, true);
+ if (err)
+ return err;
+
+ if (m->type == Z_EROFS_LCLUSTER_TYPE_NONHEAD) {
+ /* work around invalid d1 generated by pre-1.0 mkfs */
+ if (unlikely(!m->delta[1])) {
+ m->delta[1] = 1;
+ DBG_BUGON(1);
+ }
+ } else if (m->type < Z_EROFS_LCLUSTER_TYPE_MAX) {
+ if (lcn != headlcn)
+ break; /* ends at the next HEAD lcluster */
+ m->delta[1] = 1;
+ }
+ lcn += m->delta[1];
+ }
+ map->m_llen = (lcn << lclusterbits) + m->clusterofs - map->m_la;
+ return 0;
+}
+
+static int z_erofs_map_blocks_fo(struct inode *inode,
+ struct erofs_map_blocks *map, int flags)
+{
+ struct erofs_inode *vi = EROFS_I(inode);
+ struct super_block *sb = inode->i_sb;
+ bool fragment = vi->z_advise & Z_EROFS_ADVISE_FRAGMENT_PCLUSTER;
+ bool ztailpacking = vi->z_idata_size;
+ unsigned int lclusterbits = vi->z_lclusterbits;
+ struct z_erofs_maprecorder m = {
+ .inode = inode,
+ .map = map,
+ .in_mbox = erofs_inode_in_metabox(inode),
+ .compressedblks = -1,
+ };
+ unsigned int endoff;
+ unsigned long initial_lcn;
+ unsigned long long ofs, end;
+ int err;
+
+ ofs = flags & EROFS_GET_BLOCKS_FINDTAIL ? inode->i_size - 1 : map->m_la;
+ if (fragment && !(flags & EROFS_GET_BLOCKS_FINDTAIL) &&
+ !vi->z_tailextent_headlcn) {
+ map->m_la = 0;
+ map->m_llen = inode->i_size;
+ map->m_flags = EROFS_MAP_FRAGMENT;
+ return 0;
+ }
+ initial_lcn = ofs >> lclusterbits;
+ endoff = ofs & ((1 << lclusterbits) - 1);
+
+ err = z_erofs_load_lcluster_from_disk(&m, initial_lcn, false);
+ if (err)
+ goto unmap_out;
+
+ if ((flags & EROFS_GET_BLOCKS_FINDTAIL) && ztailpacking)
+ vi->z_fragmentoff = m.nextpackoff;
+ map->m_flags = EROFS_MAP_MAPPED | EROFS_MAP_PARTIAL_MAPPED;
+ end = (m.lcn + 1ULL) << lclusterbits;
+
+ if (m.type != Z_EROFS_LCLUSTER_TYPE_NONHEAD && endoff >= m.clusterofs) {
+ m.headtype = m.type;
+ map->m_la = (m.lcn << lclusterbits) | m.clusterofs;
+ /*
+ * For ztailpacking files, in order to inline data more
+ * effectively, special EOF lclusters are now supported
+ * which can have three parts at most.
+ */
+ if (ztailpacking && end > inode->i_size)
+ end = inode->i_size;
+ } else {
+ if (m.type != Z_EROFS_LCLUSTER_TYPE_NONHEAD) {
+ end = (m.lcn << lclusterbits) | m.clusterofs;
+ map->m_flags &= ~EROFS_MAP_PARTIAL_MAPPED;
+ m.delta[0] = 1;
+ }
+ /* get the corresponding first chunk */
+ err = z_erofs_extent_lookback(&m, m.delta[0]);
+ if (err)
+ goto unmap_out;
+ }
+ if (m.partialref)
+ map->m_flags |= EROFS_MAP_PARTIAL_REF;
+ map->m_llen = end - map->m_la;
+
+ if (flags & EROFS_GET_BLOCKS_FINDTAIL) {
+ vi->z_tailextent_headlcn = m.lcn;
+ /* for non-compact indexes, fragmentoff is 64 bits */
+ if (fragment && vi->datalayout == EROFS_INODE_COMPRESSED_FULL)
+ vi->z_fragmentoff |= (u64)m.pblk << 32;
+ }
+ if (ztailpacking && m.lcn == vi->z_tailextent_headlcn) {
+ map->m_flags |= EROFS_MAP_META;
+ map->m_pa = vi->z_fragmentoff;
+ map->m_plen = vi->z_idata_size;
+ if (erofs_blkoff(sb, map->m_pa) + map->m_plen > sb->s_blocksize) {
+ erofs_err(sb, "ztailpacking inline data across blocks @ nid %llu",
+ vi->nid);
+ err = -EFSCORRUPTED;
+ goto unmap_out;
+ }
+ } else if (fragment && m.lcn == vi->z_tailextent_headlcn) {
+ map->m_flags = EROFS_MAP_FRAGMENT;
+ } else {
+ map->m_pa = erofs_pos(sb, m.pblk);
+ err = z_erofs_get_extent_compressedlen(&m, initial_lcn);
+ if (err)
+ goto unmap_out;
+ }
+
+ if (m.headtype == Z_EROFS_LCLUSTER_TYPE_PLAIN) {
+ if ((vi->z_advise & Z_EROFS_ADVISE_INTERLACED_PCLUSTER) &&
+ !(map->m_flags & EROFS_MAP_META))
+ map->m_algorithmformat = Z_EROFS_COMPRESSION_INTERLACED;
+ else
+ map->m_algorithmformat = Z_EROFS_COMPRESSION_SHIFTED;
+ } else {
+ map->m_algorithmformat =
+ vi->z_algofmt[m.headtype == Z_EROFS_LCLUSTER_TYPE_HEAD2];
+ }
+
+ if ((flags & EROFS_GET_BLOCKS_FIEMAP) ||
+ ((flags & EROFS_GET_BLOCKS_READMORE) &&
+ (map->m_algorithmformat == Z_EROFS_COMPRESSION_LZMA ||
+ map->m_algorithmformat == Z_EROFS_COMPRESSION_DEFLATE ||
+ map->m_algorithmformat == Z_EROFS_COMPRESSION_ZSTD) &&
+ map->m_llen >= i_blocksize(inode))) {
+ err = z_erofs_get_extent_decompressedlen(&m);
+ if (!err)
+ map->m_flags &= ~EROFS_MAP_PARTIAL_MAPPED;
+ }
+
+unmap_out:
+ erofs_unmap_metabuf(&m.map->buf);
+ return err;
+}
+
+static int z_erofs_map_blocks_ext(struct inode *inode,
+ struct erofs_map_blocks *map, int flags)
+{
+ struct erofs_inode *vi = EROFS_I(inode);
+ struct super_block *sb = inode->i_sb;
+ bool interlaced = vi->z_advise & Z_EROFS_ADVISE_INTERLACED_PCLUSTER;
+ unsigned int recsz = z_erofs_extent_recsize(vi->z_advise);
+ erofs_off_t pos = round_up(Z_EROFS_MAP_HEADER_END(erofs_iloc(inode) +
+ vi->inode_isize + vi->xattr_isize), recsz);
+ unsigned int bmask = sb->s_blocksize - 1;
+ bool in_mbox = erofs_inode_in_metabox(inode);
+ erofs_off_t lend = inode->i_size;
+ erofs_off_t l, r, mid, pa, la, lstart;
+ struct z_erofs_extent *ext;
+ unsigned int fmt;
+ bool last;
+
+ map->m_flags = 0;
+ if (recsz <= offsetof(struct z_erofs_extent, pstart_hi)) {
+ if (recsz <= offsetof(struct z_erofs_extent, pstart_lo)) {
+ ext = erofs_read_metabuf(&map->buf, sb, pos, in_mbox);
+ if (IS_ERR(ext))
+ return PTR_ERR(ext);
+ pa = le64_to_cpu(*(__le64 *)ext);
+ pos += sizeof(__le64);
+ lstart = 0;
+ } else {
+ lstart = round_down(map->m_la, 1 << vi->z_lclusterbits);
+ pos += (lstart >> vi->z_lclusterbits) * recsz;
+ pa = EROFS_NULL_ADDR;
+ }
+
+ for (; lstart <= map->m_la; lstart += 1 << vi->z_lclusterbits) {
+ ext = erofs_read_metabuf(&map->buf, sb, pos, in_mbox);
+ if (IS_ERR(ext))
+ return PTR_ERR(ext);
+ map->m_plen = le32_to_cpu(ext->plen);
+ if (pa != EROFS_NULL_ADDR) {
+ map->m_pa = pa;
+ pa += map->m_plen & Z_EROFS_EXTENT_PLEN_MASK;
+ } else {
+ map->m_pa = le32_to_cpu(ext->pstart_lo);
+ }
+ pos += recsz;
+ }
+ last = (lstart >= round_up(lend, 1 << vi->z_lclusterbits));
+ lend = min(lstart, lend);
+ lstart -= 1 << vi->z_lclusterbits;
+ } else {
+ lstart = lend;
+ for (l = 0, r = vi->z_extents; l < r; ) {
+ mid = l + (r - l) / 2;
+ ext = erofs_read_metabuf(&map->buf, sb,
+ pos + mid * recsz, in_mbox);
+ if (IS_ERR(ext))
+ return PTR_ERR(ext);
+
+ la = le32_to_cpu(ext->lstart_lo);
+ pa = le32_to_cpu(ext->pstart_lo) |
+ (u64)le32_to_cpu(ext->pstart_hi) << 32;
+ if (recsz > offsetof(struct z_erofs_extent, lstart_hi))
+ la |= (u64)le32_to_cpu(ext->lstart_hi) << 32;
+
+ if (la > map->m_la) {
+ r = mid;
+ if (la > lend) {
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
+ lend = la;
+ } else {
+ l = mid + 1;
+ if (map->m_la == la)
+ r = min(l + 1, r);
+ lstart = la;
+ map->m_plen = le32_to_cpu(ext->plen);
+ map->m_pa = pa;
+ }
+ }
+ last = (l >= vi->z_extents);
+ }
+
+ if (lstart < lend) {
+ map->m_la = lstart;
+ if (last && (vi->z_advise & Z_EROFS_ADVISE_FRAGMENT_PCLUSTER)) {
+ map->m_flags = EROFS_MAP_FRAGMENT;
+ vi->z_fragmentoff = map->m_plen;
+ if (recsz > offsetof(struct z_erofs_extent, pstart_lo))
+ vi->z_fragmentoff |= map->m_pa << 32;
+ } else if (map->m_plen & Z_EROFS_EXTENT_PLEN_MASK) {
+ map->m_flags |= EROFS_MAP_MAPPED;
+ fmt = map->m_plen >> Z_EROFS_EXTENT_PLEN_FMT_BIT;
+ if (map->m_plen & Z_EROFS_EXTENT_PLEN_PARTIAL)
+ map->m_flags |= EROFS_MAP_PARTIAL_REF;
+ map->m_plen &= Z_EROFS_EXTENT_PLEN_MASK;
+ if (fmt) {
+ map->m_algorithmformat = --fmt;
+ if (fmt >= Z_EROFS_COMPRESSION_MAX) {
+ erofs_err(sb, "unknown algorithm %d @ pos %llu for nid %llu, please upgrade kernel",
+ fmt, map->m_la, vi->nid);
+ return -EOPNOTSUPP;
+ }
+ } else if (interlaced && !((map->m_pa | map->m_plen) & bmask))
+ map->m_algorithmformat =
+ Z_EROFS_COMPRESSION_INTERLACED;
+ else
+ map->m_algorithmformat =
+ Z_EROFS_COMPRESSION_SHIFTED;
+ }
+ }
+ map->m_llen = lend - map->m_la;
+ return 0;
+}
+
+static int z_erofs_fill_inode(struct inode *inode, struct erofs_map_blocks *map)
+{
+ struct erofs_inode *const vi = EROFS_I(inode);
+ struct super_block *const sb = inode->i_sb;
+ struct z_erofs_map_header *h;
+ erofs_off_t pos;
+ int err = 0, nr;
+
+ if (test_bit(EROFS_I_Z_INITED_BIT, &vi->flags)) {
+ /*
+ * paired with smp_mb() at the end of the function to ensure
+ * fields will only be observed after the bit is set.
+ */
+ smp_mb();
+ return 0;
+ }
+
+ if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_Z_BIT, TASK_KILLABLE))
+ return -ERESTARTSYS;
+
+ if (test_bit(EROFS_I_Z_INITED_BIT, &vi->flags))
+ goto out_unlock;
+
+ pos = ALIGN(erofs_iloc(inode) + vi->inode_isize + vi->xattr_isize, 8);
+ h = erofs_read_metabuf(&map->buf, sb, pos, erofs_inode_in_metabox(inode));
+ if (IS_ERR(h)) {
+ err = PTR_ERR(h);
+ goto out_unlock;
+ }
+
+ /*
+ * if the highest bit of the 8-byte map header is set, the whole file
+ * is stored in the packed inode. The rest bits keeps z_fragmentoff.
+ */
+ if (h->h_clusterbits >> Z_EROFS_FRAGMENT_INODE_BIT) {
+ vi->z_advise = Z_EROFS_ADVISE_FRAGMENT_PCLUSTER;
+ vi->z_fragmentoff = le64_to_cpu(*(__le64 *)h) ^ (1ULL << 63);
+ vi->z_tailextent_headlcn = 0;
+ goto done;
+ }
+ vi->z_advise = le16_to_cpu(h->h_advise);
+ vi->z_lclusterbits = sb->s_blocksize_bits + (h->h_clusterbits & 15);
+ if (vi->datalayout == EROFS_INODE_COMPRESSED_FULL &&
+ (vi->z_advise & Z_EROFS_ADVISE_EXTENTS)) {
+ vi->z_extents = le32_to_cpu(h->h_extents_lo) |
+ ((u64)le16_to_cpu(h->h_extents_hi) << 32);
+ goto done;
+ }
+
+ if (vi->z_advise & Z_EROFS_ADVISE_FRAGMENT_PCLUSTER)
+ vi->z_fragmentoff = le32_to_cpu(h->h_fragmentoff);
+ else if (vi->z_advise & Z_EROFS_ADVISE_INLINE_PCLUSTER)
+ vi->z_idata_size = le16_to_cpu(h->h_idata_size);
+ for (nr = 0; nr < 2; ++nr) {
+ vi->z_algofmt[nr] = (h->h_algorithmtype >> (4 * nr)) & 15;
+ if (vi->z_algofmt[nr] >= Z_EROFS_COMPRESSION_MAX) {
+ erofs_err(sb, "unknown HEAD%u format %u for nid %llu, please upgrade kernel",
+ nr + 1, vi->z_algofmt[nr], vi->nid);
+ err = -EOPNOTSUPP;
+ goto out_unlock;
+ }
+ }
+
+ if (!erofs_sb_has_big_pcluster(EROFS_SB(sb)) &&
+ vi->z_advise & (Z_EROFS_ADVISE_BIG_PCLUSTER_1 |
+ Z_EROFS_ADVISE_BIG_PCLUSTER_2)) {
+ erofs_err(sb, "per-inode big pcluster without sb feature for nid %llu",
+ vi->nid);
+ err = -EFSCORRUPTED;
+ goto out_unlock;
+ }
+ if (vi->datalayout == EROFS_INODE_COMPRESSED_COMPACT &&
+ !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1) ^
+ !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_2)) {
+ erofs_err(sb, "big pcluster head1/2 of compact indexes should be consistent for nid %llu",
+ vi->nid);
+ err = -EFSCORRUPTED;
+ goto out_unlock;
+ }
+
+ if (vi->z_idata_size ||
+ (vi->z_advise & Z_EROFS_ADVISE_FRAGMENT_PCLUSTER)) {
+ struct erofs_map_blocks tm = {
+ .buf = __EROFS_BUF_INITIALIZER
+ };
+
+ err = z_erofs_map_blocks_fo(inode, &tm,
+ EROFS_GET_BLOCKS_FINDTAIL);
+ erofs_put_metabuf(&tm.buf);
+ if (err < 0)
+ goto out_unlock;
+ }
+done:
+ /* paired with smp_mb() at the beginning of the function */
+ smp_mb();
+ set_bit(EROFS_I_Z_INITED_BIT, &vi->flags);
+out_unlock:
+ clear_and_wake_up_bit(EROFS_I_BL_Z_BIT, &vi->flags);
+ return err;
+}
+
+static int z_erofs_map_sanity_check(struct inode *inode,
+ struct erofs_map_blocks *map)
+{
+ struct erofs_sb_info *sbi = EROFS_I_SB(inode);
+ u64 pend;
+
+ if (!(map->m_flags & EROFS_MAP_MAPPED))
+ return 0;
+
+ DBG_BUGON(map->m_algorithmformat >= Z_EROFS_COMPRESSION_RUNTIME_MAX);
+ if (map->m_algorithmformat < Z_EROFS_COMPRESSION_MAX) {
+ if (!(sbi->available_compr_algs & BIT(map->m_algorithmformat))) {
+ erofs_err(inode->i_sb, "inconsistent algorithmtype %u for nid %llu",
+ map->m_algorithmformat, EROFS_I(inode)->nid);
+ return -EFSCORRUPTED;
+ }
+ if (EROFS_MAP_FULL(map->m_flags) && map->m_llen < map->m_plen &&
+ map->m_la + map->m_llen < inode->i_size) {
+ erofs_err(inode->i_sb, "too much compressed data @ la %llu of nid %llu",
+ map->m_la, EROFS_I(inode)->nid);
+ return -EFSCORRUPTED;
+ }
+ } else if (map->m_llen > map->m_plen) {
+ erofs_err(inode->i_sb, "not enough plain data on disk @ la %llu of nid %llu",
+ map->m_la, EROFS_I(inode)->nid);
+ return -EFSCORRUPTED;
+ }
+ if (unlikely(map->m_plen > Z_EROFS_PCLUSTER_MAX_SIZE ||
+ map->m_llen > Z_EROFS_PCLUSTER_MAX_DSIZE))
+ return -EOPNOTSUPP;
+ /* Filesystems beyond 48-bit physical block addresses are invalid */
+ if (unlikely(check_add_overflow(map->m_pa, map->m_plen, &pend) ||
+ (pend >> sbi->blkszbits) >= BIT_ULL(48)))
+ return -EFSCORRUPTED;
+ return 0;
+}
+
+int z_erofs_map_blocks_iter(struct inode *inode, struct erofs_map_blocks *map,
+ int flags)
+{
+ struct erofs_inode *const vi = EROFS_I(inode);
+ int err = 0;
+
+ trace_erofs_map_blocks_enter(inode, map, flags);
+ if (map->m_la >= inode->i_size) { /* post-EOF unmapped extent */
+ map->m_llen = map->m_la + 1 - inode->i_size;
+ map->m_la = inode->i_size;
+ map->m_flags = 0;
+ } else {
+ err = z_erofs_fill_inode(inode, map);
+ if (!err) {
+ if (vi->datalayout == EROFS_INODE_COMPRESSED_FULL &&
+ (vi->z_advise & Z_EROFS_ADVISE_EXTENTS))
+ err = z_erofs_map_blocks_ext(inode, map, flags);
+ else
+ err = z_erofs_map_blocks_fo(inode, map, flags);
+ }
+ if (!err)
+ err = z_erofs_map_sanity_check(inode, map);
+ if (err)
+ map->m_llen = 0;
+ }
+ trace_erofs_map_blocks_exit(inode, map, flags, err);
+ return err;
+}
+
+static int z_erofs_iomap_begin_report(struct inode *inode, loff_t offset,
+ loff_t length, unsigned int flags,
+ struct iomap *iomap, struct iomap *srcmap)
+{
+ int ret;
+ struct erofs_map_blocks map = { .m_la = offset };
+
+ ret = z_erofs_map_blocks_iter(inode, &map, EROFS_GET_BLOCKS_FIEMAP);
+ erofs_put_metabuf(&map.buf);
+ if (ret < 0)
+ return ret;
+
+ iomap->bdev = inode->i_sb->s_bdev;
+ iomap->offset = map.m_la;
+ iomap->length = map.m_llen;
+ if (map.m_flags & EROFS_MAP_FRAGMENT) {
+ iomap->type = IOMAP_MAPPED;
+ iomap->addr = IOMAP_NULL_ADDR;
+ } else if (map.m_flags & EROFS_MAP_MAPPED) {
+ iomap->type = IOMAP_MAPPED;
+ iomap->addr = map.m_pa;
+ } else {
+ iomap->type = IOMAP_HOLE;
+ iomap->addr = IOMAP_NULL_ADDR;
+ /*
+ * No strict rule on how to describe extents for post EOF, yet
+ * we need to do like below. Otherwise, iomap itself will get
+ * into an endless loop on post EOF.
+ *
+ * Calculate the effective offset by subtracting extent start
+ * (map.m_la) from the requested offset, and add it to length.
+ * (NB: offset >= map.m_la always)
+ */
+ if (iomap->offset >= inode->i_size)
+ iomap->length = length + offset - map.m_la;
+ }
+ iomap->flags = 0;
+ return 0;
+}
+
+static DEFINE_IOMAP_ITER_NEXT(z_erofs_iomap_next_report,
+ z_erofs_iomap_begin_report);
+
+const struct iomap_ops z_erofs_iomap_report_ops = {
+ .iomap_next = z_erofs_iomap_next_report,
+};
diff --git a/fs/erofs/zutil.c b/fs/erofs/zutil.c
new file mode 100644
index 000000000..a0ce9226b
--- /dev/null
+++ b/fs/erofs/zutil.c
@@ -0,0 +1,316 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2018 HUAWEI, Inc.
+ * https://www.huawei.com/
+ * Copyright (C) 2024 Alibaba Cloud
+ */
+#include "internal.h"
+
+struct z_erofs_gbuf {
+ spinlock_t lock;
+ void *ptr;
+ struct page **pages;
+ unsigned int nrpages;
+};
+
+static struct z_erofs_gbuf *z_erofs_gbufpool, *z_erofs_rsvbuf;
+static unsigned int z_erofs_gbuf_count, z_erofs_gbuf_nrpages,
+ z_erofs_rsv_nrpages;
+
+module_param_named(global_buffers, z_erofs_gbuf_count, uint, 0444);
+module_param_named(reserved_pages, z_erofs_rsv_nrpages, uint, 0444);
+
+atomic_long_t erofs_global_shrink_cnt; /* for all mounted instances */
+
+/* protects `erofs_sb_list_lock` and the mounted `erofs_sb_list` */
+static DEFINE_SPINLOCK(erofs_sb_list_lock);
+static LIST_HEAD(erofs_sb_list);
+static unsigned int shrinker_run_no;
+static struct shrinker *erofs_shrinker_info;
+
+static unsigned int z_erofs_gbuf_id(void)
+{
+ return raw_smp_processor_id() % z_erofs_gbuf_count;
+}
+
+void *z_erofs_get_gbuf(unsigned int requiredpages)
+ __acquires(gbuf->lock)
+{
+ struct z_erofs_gbuf *gbuf;
+
+ migrate_disable();
+ gbuf = &z_erofs_gbufpool[z_erofs_gbuf_id()];
+ spin_lock(&gbuf->lock);
+ /* check if the buffer is too small */
+ if (requiredpages > gbuf->nrpages) {
+ spin_unlock(&gbuf->lock);
+ migrate_enable();
+ /* (for sparse checker) pretend gbuf->lock is still taken */
+ __acquire(gbuf->lock);
+ return NULL;
+ }
+ return gbuf->ptr;
+}
+
+void z_erofs_put_gbuf(void *ptr) __releases(gbuf->lock)
+{
+ struct z_erofs_gbuf *gbuf;
+
+ gbuf = &z_erofs_gbufpool[z_erofs_gbuf_id()];
+ DBG_BUGON(gbuf->ptr != ptr);
+ spin_unlock(&gbuf->lock);
+ migrate_enable();
+}
+
+int z_erofs_gbuf_growsize(unsigned int nrpages)
+{
+ static DEFINE_MUTEX(gbuf_resize_mutex);
+ struct page **tmp_pages = NULL;
+ struct z_erofs_gbuf *gbuf;
+ void *ptr, *old_ptr;
+ int last, i, j;
+
+ mutex_lock(&gbuf_resize_mutex);
+ /* avoid shrinking gbufs, since no idea how many fses rely on */
+ if (nrpages <= z_erofs_gbuf_nrpages) {
+ mutex_unlock(&gbuf_resize_mutex);
+ return 0;
+ }
+
+ for (i = 0; i < z_erofs_gbuf_count; ++i) {
+ gbuf = &z_erofs_gbufpool[i];
+ tmp_pages = kzalloc_objs(*tmp_pages, nrpages);
+ if (!tmp_pages)
+ goto out;
+
+ for (j = 0; j < gbuf->nrpages; ++j)
+ tmp_pages[j] = gbuf->pages[j];
+ do {
+ last = j;
+ j = alloc_pages_bulk(GFP_KERNEL, nrpages,
+ tmp_pages);
+ if (last == j)
+ goto out;
+ } while (j != nrpages);
+
+ ptr = vmap(tmp_pages, nrpages, VM_MAP, PAGE_KERNEL);
+ if (!ptr)
+ goto out;
+
+ spin_lock(&gbuf->lock);
+ kfree(gbuf->pages);
+ gbuf->pages = tmp_pages;
+ old_ptr = gbuf->ptr;
+ gbuf->ptr = ptr;
+ gbuf->nrpages = nrpages;
+ spin_unlock(&gbuf->lock);
+ if (old_ptr)
+ vunmap(old_ptr);
+ }
+ z_erofs_gbuf_nrpages = nrpages;
+out:
+ if (i < z_erofs_gbuf_count && tmp_pages) {
+ for (j = 0; j < nrpages; ++j)
+ if (tmp_pages[j] && (j >= gbuf->nrpages ||
+ tmp_pages[j] != gbuf->pages[j]))
+ __free_page(tmp_pages[j]);
+ kfree(tmp_pages);
+ }
+ mutex_unlock(&gbuf_resize_mutex);
+ return i < z_erofs_gbuf_count ? -ENOMEM : 0;
+}
+
+int __init z_erofs_gbuf_init(void)
+{
+ unsigned int i, total = num_possible_cpus();
+
+ if (z_erofs_gbuf_count)
+ total = min(z_erofs_gbuf_count, total);
+ z_erofs_gbuf_count = total;
+
+ /* The last (special) global buffer is the reserved buffer */
+ total += !!z_erofs_rsv_nrpages;
+
+ z_erofs_gbufpool = kzalloc_objs(*z_erofs_gbufpool, total);
+ if (!z_erofs_gbufpool)
+ return -ENOMEM;
+
+ if (z_erofs_rsv_nrpages) {
+ z_erofs_rsvbuf = &z_erofs_gbufpool[total - 1];
+ z_erofs_rsvbuf->pages = kzalloc_objs(*z_erofs_rsvbuf->pages,
+ z_erofs_rsv_nrpages);
+ if (!z_erofs_rsvbuf->pages) {
+ z_erofs_rsvbuf = NULL;
+ z_erofs_rsv_nrpages = 0;
+ }
+ }
+ for (i = 0; i < total; ++i)
+ spin_lock_init(&z_erofs_gbufpool[i].lock);
+ return 0;
+}
+
+void z_erofs_gbuf_exit(void)
+{
+ int i, j;
+
+ for (i = 0; i < z_erofs_gbuf_count + (!!z_erofs_rsvbuf); ++i) {
+ struct z_erofs_gbuf *gbuf = &z_erofs_gbufpool[i];
+
+ if (gbuf->ptr) {
+ vunmap(gbuf->ptr);
+ gbuf->ptr = NULL;
+ }
+
+ if (!gbuf->pages)
+ continue;
+
+ for (j = 0; j < gbuf->nrpages; ++j)
+ if (gbuf->pages[j])
+ put_page(gbuf->pages[j]);
+ kfree(gbuf->pages);
+ gbuf->pages = NULL;
+ }
+ kfree(z_erofs_gbufpool);
+}
+
+struct page *__erofs_allocpage(struct page **pagepool, gfp_t gfp, bool tryrsv)
+{
+ struct page *page = *pagepool;
+
+ if (page) {
+ *pagepool = (struct page *)page_private(page);
+ } else if (tryrsv && z_erofs_rsvbuf && z_erofs_rsvbuf->nrpages) {
+ spin_lock(&z_erofs_rsvbuf->lock);
+ if (z_erofs_rsvbuf->nrpages)
+ page = z_erofs_rsvbuf->pages[--z_erofs_rsvbuf->nrpages];
+ spin_unlock(&z_erofs_rsvbuf->lock);
+ }
+ if (!page)
+ page = alloc_page(gfp);
+ DBG_BUGON(page && page_ref_count(page) != 1);
+ return page;
+}
+
+void erofs_release_pages(struct page **pagepool)
+{
+ while (*pagepool) {
+ struct page *page = *pagepool;
+
+ *pagepool = (struct page *)page_private(page);
+ /* try to fill reserved global pool first */
+ if (z_erofs_rsvbuf && z_erofs_rsvbuf->nrpages <
+ z_erofs_rsv_nrpages) {
+ spin_lock(&z_erofs_rsvbuf->lock);
+ if (z_erofs_rsvbuf->nrpages < z_erofs_rsv_nrpages) {
+ z_erofs_rsvbuf->pages[z_erofs_rsvbuf->nrpages++]
+ = page;
+ spin_unlock(&z_erofs_rsvbuf->lock);
+ continue;
+ }
+ spin_unlock(&z_erofs_rsvbuf->lock);
+ }
+ put_page(page);
+ }
+}
+
+void erofs_shrinker_register(struct super_block *sb)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+
+ mutex_init(&sbi->umount_mutex);
+
+ spin_lock(&erofs_sb_list_lock);
+ list_add(&sbi->list, &erofs_sb_list);
+ spin_unlock(&erofs_sb_list_lock);
+}
+
+void erofs_shrinker_unregister(struct super_block *sb)
+{
+ struct erofs_sb_info *const sbi = EROFS_SB(sb);
+
+ mutex_lock(&sbi->umount_mutex);
+ while (!xa_empty(&sbi->managed_pslots)) {
+ z_erofs_shrink_scan(sbi, ~0UL);
+ cond_resched();
+ }
+ spin_lock(&erofs_sb_list_lock);
+ list_del(&sbi->list);
+ spin_unlock(&erofs_sb_list_lock);
+ mutex_unlock(&sbi->umount_mutex);
+}
+
+static unsigned long erofs_shrink_count(struct shrinker *shrink,
+ struct shrink_control *sc)
+{
+ return atomic_long_read(&erofs_global_shrink_cnt) ?: SHRINK_EMPTY;
+}
+
+static unsigned long erofs_shrink_scan(struct shrinker *shrink,
+ struct shrink_control *sc)
+{
+ struct erofs_sb_info *sbi;
+ struct list_head *p;
+
+ unsigned long nr = sc->nr_to_scan;
+ unsigned int run_no;
+ unsigned long freed = 0;
+
+ spin_lock(&erofs_sb_list_lock);
+ do {
+ run_no = ++shrinker_run_no;
+ } while (run_no == 0);
+
+ /* Iterate over all mounted superblocks and try to shrink them */
+ p = erofs_sb_list.next;
+ while (p != &erofs_sb_list) {
+ sbi = list_entry(p, struct erofs_sb_info, list);
+
+ /*
+ * We move the ones we do to the end of the list, so we stop
+ * when we see one we have already done.
+ */
+ if (sbi->shrinker_run_no == run_no)
+ break;
+
+ if (!mutex_trylock(&sbi->umount_mutex)) {
+ p = p->next;
+ continue;
+ }
+
+ spin_unlock(&erofs_sb_list_lock);
+ sbi->shrinker_run_no = run_no;
+ freed += z_erofs_shrink_scan(sbi, nr - freed);
+ spin_lock(&erofs_sb_list_lock);
+ /* Get the next list element before we move this one */
+ p = p->next;
+
+ /*
+ * Move this one to the end of the list to provide some
+ * fairness.
+ */
+ list_move_tail(&sbi->list, &erofs_sb_list);
+ mutex_unlock(&sbi->umount_mutex);
+
+ if (freed >= nr)
+ break;
+ }
+ spin_unlock(&erofs_sb_list_lock);
+ return freed;
+}
+
+int __init erofs_init_shrinker(void)
+{
+ erofs_shrinker_info = shrinker_alloc(0, "erofs-shrinker");
+ if (!erofs_shrinker_info)
+ return -ENOMEM;
+
+ erofs_shrinker_info->count_objects = erofs_shrink_count;
+ erofs_shrinker_info->scan_objects = erofs_shrink_scan;
+ shrinker_register(erofs_shrinker_info);
+ return 0;
+}
+
+void erofs_exit_shrinker(void)
+{
+ shrinker_free(erofs_shrinker_info);
+}
generated by cgit v1.3.1 (git 2.54.0) at 2026-10-11 17:08:05 +0000