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-rw-r--r--fs/btrfs/lzo.c604
1 files changed, 604 insertions, 0 deletions
diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
new file mode 100644
index 000000000..2f0996692
--- /dev/null
+++ b/fs/btrfs/lzo.c
@@ -0,0 +1,604 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2008 Oracle. All rights reserved.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/sched.h>
+#include <linux/pagemap.h>
+#include <linux/bio.h>
+#include <linux/lzo.h>
+#include <linux/refcount.h>
+#include "messages.h"
+#include "compression.h"
+#include "ctree.h"
+#include "super.h"
+#include "btrfs_inode.h"
+
+#define LZO_LEN 4
+
+/*
+ * Btrfs LZO compression format
+ *
+ * Regular and inlined LZO compressed data extents consist of:
+ *
+ * 1. Header
+ * Fixed size. LZO_LEN (4) bytes long, LE32.
+ * Records the total size (including the header) of compressed data.
+ *
+ * 2. Segment(s)
+ * Variable size. Each segment includes one segment header, followed by data
+ * payload.
+ * One regular LZO compressed extent can have one or more segments.
+ * For inlined LZO compressed extent, only one segment is allowed.
+ * One segment represents at most one sector of uncompressed data.
+ *
+ * 2.1 Segment header
+ * Fixed size. LZO_LEN (4) bytes long, LE32.
+ * Records the total size of the segment (not including the header).
+ * Segment header never crosses sector boundary, thus it's possible to
+ * have at most 3 padding zeros at the end of the sector.
+ *
+ * 2.2 Data Payload
+ * Variable size. Size up limit should be lzo1x_worst_compress(sectorsize)
+ * which is 4419 for a 4KiB sectorsize.
+ *
+ * Example with 4K sectorsize:
+ * Page 1:
+ * 0 0x2 0x4 0x6 0x8 0xa 0xc 0xe 0x10
+ * 0x0000 | Header | SegHdr 01 | Data payload 01 ... |
+ * ...
+ * 0x0ff0 | SegHdr N | Data payload N ... |00|
+ * ^^ padding zeros
+ * Page 2:
+ * 0x1000 | SegHdr N+1| Data payload N+1 ... |
+ */
+
+struct workspace {
+ void *mem;
+ void *buf; /* where decompressed data goes */
+ void *cbuf; /* where compressed data goes */
+ struct list_head list;
+};
+
+static u32 workspace_buf_length(const struct btrfs_fs_info *fs_info)
+{
+ return lzo1x_worst_compress(fs_info->sectorsize);
+}
+static u32 workspace_cbuf_length(const struct btrfs_fs_info *fs_info)
+{
+ return lzo1x_worst_compress(fs_info->sectorsize);
+}
+
+void lzo_free_workspace(struct list_head *ws)
+{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+
+ kvfree(workspace->buf);
+ kvfree(workspace->cbuf);
+ kvfree(workspace->mem);
+ kfree(workspace);
+}
+
+struct list_head *lzo_alloc_workspace(struct btrfs_fs_info *fs_info)
+{
+ struct workspace *workspace;
+
+ workspace = kzalloc_obj(*workspace);
+ if (!workspace)
+ return ERR_PTR(-ENOMEM);
+
+ workspace->mem = kvmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL | __GFP_NOWARN);
+ workspace->buf = kvmalloc(workspace_buf_length(fs_info), GFP_KERNEL | __GFP_NOWARN);
+ workspace->cbuf = kvmalloc(workspace_cbuf_length(fs_info), GFP_KERNEL | __GFP_NOWARN);
+ if (!workspace->mem || !workspace->buf || !workspace->cbuf)
+ goto fail;
+
+ INIT_LIST_HEAD(&workspace->list);
+
+ return &workspace->list;
+fail:
+ lzo_free_workspace(&workspace->list);
+ return ERR_PTR(-ENOMEM);
+}
+
+/*
+ * Write data into @out_folio and queue it into @out_bio.
+ *
+ * Return 0 if everything is fine and @total_out will be increased.
+ * Return <0 for error.
+ *
+ * The @out_folio can be NULL after a full folio is queued.
+ * Thus the caller should check and allocate a new folio when needed.
+ */
+static int write_and_queue_folio(struct bio *out_bio, struct folio **out_folio,
+ u32 *total_out, u32 write_len)
+{
+ const u32 fsize = folio_size(*out_folio);
+ const u32 foffset = offset_in_folio(*out_folio, *total_out);
+
+ ASSERT(out_folio && *out_folio);
+ /* Should not cross folio boundary. */
+ ASSERT(foffset + write_len <= fsize);
+
+ /* We can not use bio_add_folio_nofail() which doesn't do any merge. */
+ if (!bio_add_folio(out_bio, *out_folio, write_len, foffset)) {
+ /*
+ * We have allocated a bio that havs BTRFS_MAX_COMPRESSED_PAGES
+ * vecs, and all ranges inside the same folio should have been
+ * merged. If bio_add_folio() still failed, that means we have
+ * reached the bvec limits.
+ *
+ * This should only happen at the beginning of a folio, and
+ * caller is responsible for releasing the folio, since it's
+ * not yet queued into the bio.
+ */
+ ASSERT(IS_ALIGNED(*total_out, fsize));
+ return -E2BIG;
+ }
+
+ *total_out += write_len;
+ /*
+ * The full folio has been filled and queued, reset @out_folio to NULL,
+ * so that error handling is fully handled by the bio.
+ */
+ if (IS_ALIGNED(*total_out, fsize))
+ *out_folio = NULL;
+ return 0;
+}
+
+/*
+ * Copy compressed data to bio.
+ *
+ * @out_bio: The bio that will contain all the compressed data.
+ * @compressed_data: The compressed data of this segment.
+ * @compressed_size: The size of the compressed data.
+ * @out_folio: The current output folio, will be updated if a new
+ * folio is allocated.
+ * @total_out: The total bytes of current output.
+ * @max_out: The maximum size of the compressed data.
+ *
+ * Will do:
+ *
+ * - Write a segment header into the destination
+ * - Copy the compressed buffer into the destination
+ * - Make sure we have enough space in the last sector to fit a segment header
+ * If not, we will pad at most (LZO_LEN (4)) - 1 bytes of zeros.
+ * - If a full folio is filled, it will be queued into @out_bio, and @out_folio
+ * will be updated.
+ *
+ * Will allocate new pages when needed.
+ */
+static int copy_compressed_data_to_bio(struct btrfs_fs_info *fs_info,
+ struct bio *out_bio,
+ const char *compressed_data,
+ size_t compressed_size,
+ struct folio **out_folio,
+ u32 *total_out, u32 max_out)
+{
+ const u32 sectorsize = fs_info->sectorsize;
+ const u32 sectorsize_bits = fs_info->sectorsize_bits;
+ const u32 fsize = btrfs_min_folio_size(fs_info);
+ const u32 old_size = out_bio->bi_iter.bi_size;
+ u32 copy_start;
+ u32 sector_bytes_left;
+ char *kaddr;
+ int ret;
+
+ ASSERT(out_folio);
+
+ /* There should be at least a lzo header queued. */
+ ASSERT(old_size);
+ ASSERT(old_size == *total_out);
+
+ /*
+ * We never allow a segment header crossing sector boundary, previous
+ * run should ensure we have enough space left inside the sector.
+ */
+ ASSERT((old_size >> sectorsize_bits) == (old_size + LZO_LEN - 1) >> sectorsize_bits);
+
+ if (!*out_folio) {
+ *out_folio = btrfs_alloc_compr_folio(fs_info, GFP_NOFS);
+ if (!*out_folio)
+ return -ENOMEM;
+ }
+
+ /* Write the segment header first. */
+ kaddr = kmap_local_folio(*out_folio, offset_in_folio(*out_folio, *total_out));
+ put_unaligned_le32(compressed_size, kaddr);
+ kunmap_local(kaddr);
+ ret = write_and_queue_folio(out_bio, out_folio, total_out, LZO_LEN);
+ if (ret < 0)
+ return ret;
+
+ copy_start = *total_out;
+
+ /* Copy compressed data. */
+ while (*total_out - copy_start < compressed_size) {
+ u32 copy_len = min_t(u32, sectorsize - *total_out % sectorsize,
+ copy_start + compressed_size - *total_out);
+ u32 foffset = *total_out & (fsize - 1);
+
+ /* With the range copied, we're larger than the original range. */
+ if (((*total_out + copy_len) >> sectorsize_bits) >=
+ max_out >> sectorsize_bits)
+ return -E2BIG;
+
+ if (!*out_folio) {
+ *out_folio = btrfs_alloc_compr_folio(fs_info, GFP_NOFS);
+ if (!*out_folio)
+ return -ENOMEM;
+ }
+
+ kaddr = kmap_local_folio(*out_folio, foffset);
+ memcpy(kaddr, compressed_data + *total_out - copy_start, copy_len);
+ kunmap_local(kaddr);
+ ret = write_and_queue_folio(out_bio, out_folio, total_out, copy_len);
+ if (ret < 0)
+ return ret;
+ }
+
+ /*
+ * Check if we can fit the next segment header into the remaining space
+ * of the sector.
+ */
+ sector_bytes_left = round_up(*total_out, sectorsize) - *total_out;
+ if (sector_bytes_left >= LZO_LEN || sector_bytes_left == 0)
+ return 0;
+
+ ASSERT(*out_folio);
+
+ /* The remaining size is not enough, pad it with zeros */
+ folio_zero_range(*out_folio, offset_in_folio(*out_folio, *total_out), sector_bytes_left);
+ return write_and_queue_folio(out_bio, out_folio, total_out, sector_bytes_left);
+}
+
+int lzo_compress_bio(struct list_head *ws, struct compressed_bio *cb)
+{
+ struct btrfs_inode *inode = cb->bbio.inode;
+ struct btrfs_fs_info *fs_info = inode->root->fs_info;
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+ struct bio *bio = &cb->bbio.bio;
+ const u64 start = cb->start;
+ const u32 len = cb->len;
+ const u32 sectorsize = fs_info->sectorsize;
+ const u32 min_folio_size = btrfs_min_folio_size(fs_info);
+ struct address_space *mapping = inode->vfs_inode.i_mapping;
+ struct folio *folio_in = NULL;
+ struct folio *folio_out = NULL;
+ char *sizes_ptr;
+ int ret = 0;
+ /* Points to the file offset of input data. */
+ u64 cur_in = start;
+ /* Points to the current output byte. */
+ u32 total_out = 0;
+
+ ASSERT(bio->bi_iter.bi_size == 0);
+ ASSERT(len);
+
+ folio_out = btrfs_alloc_compr_folio(fs_info, GFP_NOFS);
+ if (!folio_out)
+ return -ENOMEM;
+
+ /* Queue a segment header first. */
+ ret = write_and_queue_folio(bio, &folio_out, &total_out, LZO_LEN);
+ /* The first header should not fail. */
+ ASSERT(ret == 0);
+
+ while (cur_in < start + len) {
+ char *data_in;
+ const u32 sectorsize_mask = sectorsize - 1;
+ u32 sector_off = (cur_in - start) & sectorsize_mask;
+ u32 in_len;
+ size_t out_len;
+
+ /* Get the input page first. */
+ if (!folio_in) {
+ ret = btrfs_compress_filemap_get_folio(mapping, cur_in, &folio_in);
+ if (ret < 0)
+ goto out;
+ }
+
+ /* Compress at most one sector of data each time. */
+ in_len = min_t(u32, start + len - cur_in, sectorsize - sector_off);
+ ASSERT(in_len);
+ data_in = kmap_local_folio(folio_in, offset_in_folio(folio_in, cur_in));
+ ret = lzo1x_1_compress(data_in, in_len, workspace->cbuf, &out_len,
+ workspace->mem);
+ kunmap_local(data_in);
+ if (unlikely(ret < 0)) {
+ /* lzo1x_1_compress never fails. */
+ ret = -EIO;
+ goto out;
+ }
+
+ ret = copy_compressed_data_to_bio(fs_info, bio, workspace->cbuf, out_len,
+ &folio_out, &total_out, len);
+ if (ret < 0)
+ goto out;
+
+ cur_in += in_len;
+
+ /*
+ * Check if we're making it bigger after two sectors. And if
+ * it is so, give up.
+ */
+ if (cur_in - start > sectorsize * 2 && cur_in - start < total_out) {
+ ret = -E2BIG;
+ goto out;
+ }
+
+ /* Check if we have reached input folio boundary. */
+ if (IS_ALIGNED(cur_in, min_folio_size)) {
+ folio_put(folio_in);
+ folio_in = NULL;
+ }
+ }
+ /*
+ * The last folio is already queued. Bio is responsible for freeing
+ * those folios now.
+ */
+ folio_out = NULL;
+
+ /* Store the size of all chunks of compressed data */
+ sizes_ptr = kmap_local_folio(bio_first_folio_all(bio), 0);
+ put_unaligned_le32(total_out, sizes_ptr);
+ kunmap_local(sizes_ptr);
+out:
+ /*
+ * We can only free the folio that has no part queued into the bio.
+ *
+ * As any folio that is already queued into bio will be released by
+ * the endio function of bio.
+ */
+ if (folio_out && IS_ALIGNED(total_out, min_folio_size)) {
+ btrfs_free_compr_folio(folio_out);
+ folio_out = NULL;
+ }
+ if (folio_in)
+ folio_put(folio_in);
+ return ret;
+}
+
+static struct folio *get_current_folio(struct compressed_bio *cb, struct folio_iter *fi,
+ u32 *cur_folio_index, u32 cur_in)
+{
+ struct btrfs_fs_info *fs_info = cb_to_fs_info(cb);
+ const u32 min_folio_shift = PAGE_SHIFT + fs_info->block_min_order;
+
+ ASSERT(cur_folio_index);
+
+ /* Need to switch to the next folio. */
+ if (cur_in >> min_folio_shift != *cur_folio_index) {
+ /* We can only do the switch one folio a time. */
+ ASSERT(cur_in >> min_folio_shift == *cur_folio_index + 1);
+
+ bio_next_folio(fi, &cb->bbio.bio);
+ (*cur_folio_index)++;
+ }
+ return fi->folio;
+}
+
+/*
+ * Copy the compressed segment payload into @dest.
+ *
+ * For the payload there will be no padding, just need to do page switching.
+ */
+static void copy_compressed_segment(struct compressed_bio *cb,
+ struct folio_iter *fi, u32 *cur_folio_index,
+ char *dest, u32 len, u32 *cur_in)
+{
+ u32 orig_in = *cur_in;
+
+ while (*cur_in < orig_in + len) {
+ struct folio *cur_folio = get_current_folio(cb, fi, cur_folio_index, *cur_in);
+ u32 copy_len;
+
+ ASSERT(cur_folio);
+ copy_len = min_t(u32, orig_in + len - *cur_in,
+ folio_size(cur_folio) - offset_in_folio(cur_folio, *cur_in));
+ ASSERT(copy_len);
+
+ memcpy_from_folio(dest + *cur_in - orig_in, cur_folio,
+ offset_in_folio(cur_folio, *cur_in), copy_len);
+
+ *cur_in += copy_len;
+ }
+}
+
+int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
+{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+ struct btrfs_fs_info *fs_info = cb->bbio.inode->root->fs_info;
+ const u32 sectorsize = fs_info->sectorsize;
+ const u32 compressed_len = bio_get_size(&cb->bbio.bio);
+ struct folio_iter fi;
+ char *kaddr;
+ int ret;
+ /* Compressed data length, can be unaligned */
+ u32 len_in;
+ /* Offset inside the compressed data */
+ u32 cur_in = 0;
+ /* Bytes decompressed so far */
+ u32 cur_out = 0;
+ /* The current folio index number inside the bio. */
+ u32 cur_folio_index = 0;
+
+ bio_first_folio(&fi, &cb->bbio.bio, 0);
+ /* There must be a compressed folio and matches the sectorsize. */
+ if (unlikely(!fi.folio))
+ return -EINVAL;
+ ASSERT(folio_size(fi.folio) == btrfs_min_folio_size(fs_info));
+ kaddr = kmap_local_folio(fi.folio, 0);
+ len_in = get_unaligned_le32(kaddr);
+ kunmap_local(kaddr);
+ cur_in += LZO_LEN;
+
+ /*
+ * LZO header length check
+ *
+ * The total length should not exceed the maximum extent length,
+ * and all sectors should be used.
+ * If this happens, it means the compressed extent is corrupted.
+ */
+ if (unlikely(len_in > min_t(size_t, BTRFS_MAX_COMPRESSED, compressed_len) ||
+ round_up(len_in, sectorsize) < compressed_len)) {
+ struct btrfs_inode *inode = cb->bbio.inode;
+
+ btrfs_err(fs_info,
+"lzo header invalid, root %llu inode %llu offset %llu lzo len %u compressed len %u",
+ btrfs_root_id(inode->root), btrfs_ino(inode),
+ cb->start, len_in, compressed_len);
+ return -EUCLEAN;
+ }
+
+ /* Go through each lzo segment */
+ while (cur_in < len_in) {
+ struct folio *cur_folio;
+ /* Length of the compressed segment */
+ u32 seg_len;
+ u32 sector_bytes_left;
+ size_t out_len = lzo1x_worst_compress(sectorsize);
+
+ /*
+ * We should always have enough space for one segment header
+ * inside current sector.
+ */
+ ASSERT(cur_in / sectorsize ==
+ (cur_in + LZO_LEN - 1) / sectorsize);
+ cur_folio = get_current_folio(cb, &fi, &cur_folio_index, cur_in);
+ ASSERT(cur_folio);
+ kaddr = kmap_local_folio(cur_folio, 0);
+ seg_len = get_unaligned_le32(kaddr + offset_in_folio(cur_folio, cur_in));
+ kunmap_local(kaddr);
+ cur_in += LZO_LEN;
+
+ if (unlikely(seg_len > workspace_cbuf_length(fs_info))) {
+ struct btrfs_inode *inode = cb->bbio.inode;
+
+ /*
+ * seg_len shouldn't be larger than we have allocated
+ * for workspace->cbuf
+ */
+ btrfs_err(fs_info,
+ "lzo segment too big, root %llu inode %llu offset %llu len %u",
+ btrfs_root_id(inode->root), btrfs_ino(inode),
+ cb->start, seg_len);
+ return -EIO;
+ }
+
+ /* The segment must not extend beyond the compressed input. */
+ if (unlikely(cur_in + seg_len > compressed_len)) {
+ struct btrfs_inode *inode = cb->bbio.inode;
+
+ btrfs_err(fs_info,
+ "lzo segment overflows compressed input, root %llu inode %llu offset %llu cur_in %u len %u compressed len %u",
+ btrfs_root_id(inode->root), btrfs_ino(inode),
+ cb->start, cur_in, seg_len, compressed_len);
+ return -EUCLEAN;
+ }
+
+ /* Copy the compressed segment payload into workspace */
+ copy_compressed_segment(cb, &fi, &cur_folio_index, workspace->cbuf,
+ seg_len, &cur_in);
+
+ /* Decompress the data */
+ ret = lzo1x_decompress_safe(workspace->cbuf, seg_len,
+ workspace->buf, &out_len);
+ if (unlikely(ret != LZO_E_OK)) {
+ struct btrfs_inode *inode = cb->bbio.inode;
+
+ btrfs_err(fs_info,
+ "lzo decompression failed, error %d root %llu inode %llu offset %llu",
+ ret, btrfs_root_id(inode->root), btrfs_ino(inode),
+ cb->start);
+ return -EIO;
+ }
+
+ /* Copy the data into inode pages */
+ ret = btrfs_decompress_buf2page(workspace->buf, out_len, cb, cur_out);
+ cur_out += out_len;
+
+ /* All data read, exit */
+ if (ret == 0)
+ return 0;
+ ret = 0;
+
+ /* Check if the sector has enough space for a segment header */
+ sector_bytes_left = sectorsize - (cur_in % sectorsize);
+ if (sector_bytes_left >= LZO_LEN)
+ continue;
+
+ /* Skip the padding zeros */
+ cur_in += sector_bytes_left;
+ }
+
+ return 0;
+}
+
+int lzo_decompress(struct list_head *ws, const u8 *data_in,
+ struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
+ size_t destlen)
+{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+ struct btrfs_fs_info *fs_info = folio_to_fs_info(dest_folio);
+ const u32 sectorsize = fs_info->sectorsize;
+ size_t in_len;
+ size_t out_len;
+ size_t max_segment_len = workspace_buf_length(fs_info);
+ int ret;
+
+ if (unlikely(srclen <= LZO_LEN * 2 ||
+ srclen > max_segment_len + LZO_LEN * 2)) {
+ btrfs_err(fs_info, "invalid lzo header length, has %zu expect (%u, %zu)",
+ srclen, LZO_LEN * 2, max_segment_len + LZO_LEN * 2);
+ return -EUCLEAN;
+ }
+
+ in_len = get_unaligned_le32(data_in);
+ if (unlikely(in_len != srclen)) {
+ btrfs_err(fs_info, "invalid lzo header length, has %zu expect %zu",
+ in_len, srclen);
+ return -EUCLEAN;
+ }
+ data_in += LZO_LEN;
+
+ in_len = get_unaligned_le32(data_in);
+ if (unlikely(in_len != srclen - LZO_LEN * 2)) {
+ btrfs_err(fs_info, "invalid lzo segment length, has %zu expect %zu",
+ in_len, srclen - LZO_LEN * 2);
+ return -EUCLEAN;
+ }
+ data_in += LZO_LEN;
+
+ out_len = sectorsize;
+ ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len);
+ if (unlikely(ret != LZO_E_OK)) {
+ struct btrfs_inode *inode = folio_to_inode(dest_folio);
+
+ btrfs_err(fs_info,
+ "lzo decompression failed, error %d root %llu inode %llu offset %llu",
+ ret, btrfs_root_id(inode->root), btrfs_ino(inode),
+ folio_pos(dest_folio));
+ return -EIO;
+ }
+
+ ASSERT(out_len <= sectorsize);
+ memcpy_to_folio(dest_folio, dest_pgoff, workspace->buf, out_len);
+ /* Early end, considered as an error. */
+ if (unlikely(out_len < destlen)) {
+ folio_zero_range(dest_folio, dest_pgoff + out_len, destlen - out_len);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+const struct btrfs_compress_levels btrfs_lzo_compress = {
+ .max_level = 1,
+ .default_level = 1,
+};
generated by cgit v1.3.1 (git 2.54.0) at 2026-10-12 14:29:19 +0000