Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 726 insertions, 0 deletions

diff --git a/fs/ntfs/wof.c b/fs/ntfs/wof.c
new file mode 100644
index 000000000..8f84c2212
--- /dev/null
+++ b/fs/ntfs/wof.c
@@ -0,0 +1,726 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Windows System Compression (WOF) decompression glue.
+ *
+ * Copyright (c) 2026 LG Electronics Co., Ltd.
+ */
+
+#include <linux/fs.h>
+#include <linux/blkdev.h>
+#include <linux/overflow.h>
+#include <linux/pagemap.h>
+#include <linux/sched/mm.h>
+#include <linux/slab.h>
+#include <linux/unaligned.h>
+#include <linux/vmalloc.h>
+
+#include "ntfs.h"
+#include "inode.h"
+#include "debug.h"
+#include "ntfs_codec.h"
+#include "attrib.h"
+
+static const __le16 WOF_NAME[] = {
+	cpu_to_le16('W'), cpu_to_le16('o'), cpu_to_le16('f'),
+	cpu_to_le16('C'), cpu_to_le16('o'), cpu_to_le16('m'),
+	cpu_to_le16('p'), cpu_to_le16('r'), cpu_to_le16('e'),
+	cpu_to_le16('s'), cpu_to_le16('s'), cpu_to_le16('e'),
+	cpu_to_le16('d'), cpu_to_le16('D'), cpu_to_le16('a'),
+	cpu_to_le16('t'), cpu_to_le16('a'),
+};
+
+#define WOF_NAME_LEN 17
+
+#define NTFS_WOF_MAX_COMP_UNIT (1U << 15)
+#define NTFS_WOF_MAX_PAGES \
+	DIV_ROUND_UP(NTFS_WOF_MAX_COMP_UNIT + PAGE_SIZE - 1, PAGE_SIZE)
+
+struct ntfs_wof_workspace {
+	struct mutex *lock;
+	const struct ntfs_codec_ops *codec;
+	u32 comp_unit;
+	void *input;
+	size_t input_size;
+	void *output;
+	void *scratch;
+};
+
+static DEFINE_MUTEX(ntfs_wof_xpress4k_lock);
+static DEFINE_MUTEX(ntfs_wof_xpress8k_lock);
+static DEFINE_MUTEX(ntfs_wof_xpress16k_lock);
+static DEFINE_MUTEX(ntfs_wof_lzx32k_lock);
+
+static struct ntfs_wof_workspace ntfs_wof_xpress4k_workspace = {
+	.lock = &ntfs_wof_xpress4k_lock,
+	.codec = &ntfs_xpress4k_codec_ops,
+	.comp_unit = 1U << 12,
+};
+
+static struct ntfs_wof_workspace ntfs_wof_xpress8k_workspace = {
+	.lock = &ntfs_wof_xpress8k_lock,
+	.codec = &ntfs_xpress8k_codec_ops,
+	.comp_unit = 1U << 13,
+};
+
+static struct ntfs_wof_workspace ntfs_wof_xpress16k_workspace = {
+	.lock = &ntfs_wof_xpress16k_lock,
+	.codec = &ntfs_xpress16k_codec_ops,
+	.comp_unit = 1U << 14,
+};
+
+static struct ntfs_wof_workspace ntfs_wof_lzx32k_workspace = {
+	.lock = &ntfs_wof_lzx32k_lock,
+	.codec = &ntfs_lzx32k_codec_ops,
+	.comp_unit = 1U << 15,
+};
+
+static struct ntfs_wof_workspace *const ntfs_wof_workspaces[] = {
+	&ntfs_wof_xpress4k_workspace,
+	&ntfs_wof_xpress8k_workspace,
+	&ntfs_wof_xpress16k_workspace,
+	&ntfs_wof_lzx32k_workspace,
+};
+
+static struct ntfs_wof_workspace *ntfs_wof_workspace(u8 block_size_bits)
+{
+	switch (block_size_bits) {
+	case 12:
+		return &ntfs_wof_xpress4k_workspace;
+	case 13:
+		return &ntfs_wof_xpress8k_workspace;
+	case 14:
+		return &ntfs_wof_xpress16k_workspace;
+	case 15:
+		return &ntfs_wof_lzx32k_workspace;
+	default:
+		return NULL;
+	}
+}
+
+static int ntfs_wof_workspace_prepare(struct ntfs_wof_workspace *ws)
+{
+	void *input, *output, *scratch;
+	size_t scratch_size;
+
+	if (ws->input)
+		return 0;
+
+	ws->input_size = round_up((size_t)ws->comp_unit + 511, 512);
+	scratch_size = ws->codec->scratch_size(ws->comp_unit);
+	if (!scratch_size)
+		return -EINVAL;
+
+	input = kvmalloc(ws->input_size, GFP_NOFS);
+	output = kvmalloc(ws->comp_unit, GFP_NOFS);
+	scratch = kvzalloc(scratch_size, GFP_NOFS);
+	if (!input || !output || !scratch) {
+		kvfree(input);
+		kvfree(output);
+		kvfree(scratch);
+		return -ENOMEM;
+	}
+
+	ws->input = input;
+	ws->output = output;
+	ws->scratch = scratch;
+	return 0;
+}
+
+void ntfs_wof_free_workspaces(void)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(ntfs_wof_workspaces); i++) {
+		struct ntfs_wof_workspace *ws = ntfs_wof_workspaces[i];
+
+		mutex_lock(ws->lock);
+		kvfree(ws->input);
+		kvfree(ws->output);
+		kvfree(ws->scratch);
+		ws->input = NULL;
+		ws->output = NULL;
+		ws->scratch = NULL;
+		mutex_unlock(ws->lock);
+	}
+}
+
+static int ntfs_bdev_read_from_rl(struct ntfs_volume *vol,
+				  struct runlist *runlist,
+				  sector_t start_sector, u64 sector_count,
+				  void *buf)
+{
+	struct runlist_element *rl;
+	u32 sec_per_clu_bits;
+	s64 vcn;
+	u64 sec_off;
+	size_t buf_off = 0;
+	unsigned int nofs_flags;
+	int err;
+
+	if (vol->cluster_size_bits < 9)
+		return -EINVAL;
+	sec_per_clu_bits = vol->cluster_size_bits - 9;
+	vcn = start_sector >> sec_per_clu_bits;
+	sec_off = start_sector & ((1ULL << sec_per_clu_bits) - 1);
+
+	nofs_flags = memalloc_nofs_save();
+	down_read(&runlist->lock);
+	if (!runlist->rl) {
+		err = -EINVAL;
+		goto out_unlock;
+	}
+
+	rl = __ntfs_attr_find_vcn_nolock(runlist, vcn);
+	if (IS_ERR(rl)) {
+		err = PTR_ERR(rl);
+		goto out_unlock;
+	}
+
+	while (sector_count > 0) {
+		s64 lcn;
+		s64 rl_end;
+		u64 byte_off, byte_len, sectors, available;
+
+		if (rl->length <= 0 || vcn < rl->vcn) {
+			err = -EINVAL;
+			goto out_unlock;
+		}
+
+		lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
+		if (lcn < 0 && lcn != LCN_HOLE) {
+			err = -EINVAL;
+			goto out_unlock;
+		}
+
+		if (check_add_overflow(rl->vcn, rl->length, &rl_end) ||
+		    rl_end <= vcn ||
+		    (u64)(rl_end - vcn) > (U64_MAX >> sec_per_clu_bits)) {
+			err = -EOVERFLOW;
+			goto out_unlock;
+		}
+		available = (u64)(rl_end - vcn) << sec_per_clu_bits;
+		if (available <= sec_off) {
+			err = -EINVAL;
+			goto out_unlock;
+		}
+		available -= sec_off;
+		sectors = min_t(u64, sector_count, available);
+		if (check_mul_overflow(sectors, (u64)SECTOR_SIZE, &byte_len) ||
+		    byte_len > SIZE_MAX - buf_off) {
+			err = -EOVERFLOW;
+			goto out_unlock;
+		}
+
+		if (lcn == LCN_HOLE) {
+			memset((u8 *)buf + buf_off, 0, byte_len);
+		} else {
+			byte_off = ntfs_cluster_to_bytes(vol, lcn);
+			if (check_add_overflow(byte_off, sec_off << 9,
+					       &byte_off) ||
+			    byte_off > S64_MAX) {
+				err = -EOVERFLOW;
+				goto out_unlock;
+			}
+			err = ntfs_bdev_read(vol->sb->s_bdev,
+					     (char *)buf + buf_off,
+					     (loff_t)byte_off, byte_len);
+			if (err)
+				goto out_unlock;
+		}
+
+		buf_off += byte_len;
+		sector_count -= sectors;
+		rl++;
+		vcn = rl->vcn;
+		sec_off = 0;
+	}
+
+	err = 0;
+out_unlock:
+	up_read(&runlist->lock);
+	memalloc_nofs_restore(nofs_flags);
+	return err;
+}
+
+static int parse_wof_chunk_table(struct ntfs_inode *base_ni,
+				 struct ntfs_inode *ni, u64 chunk_idx,
+				 u64 chunk_count, u32 decomp_size,
+				 u64 *chunk_offset, u32 *chunk_size,
+				 void *table_buf, size_t table_buf_size)
+{
+	u8 bytes_per_off;
+	u8 *buf;
+	u64 off[2];
+	u64 byte_off, chunk_data_size, table_size;
+	u32 bytes_to_read;
+	int ret = 0;
+
+	if (i_size_read(VFS_I(base_ni)) < (1ULL << 32))
+		bytes_per_off = sizeof(__le32);
+	else
+		bytes_per_off = sizeof(__le64);
+
+	if (!chunk_count || chunk_idx >= chunk_count)
+		return -EINVAL;
+
+	table_size = (chunk_count - 1) * bytes_per_off;
+	if (ni->data_size < 0 || (u64)ni->data_size < table_size)
+		return -EINVAL;
+	chunk_data_size = (u64)ni->data_size - table_size;
+
+	if (chunk_count == 1) {
+		if (chunk_data_size > decomp_size)
+			return -EINVAL;
+		*chunk_offset = 0;
+		*chunk_size = chunk_data_size;
+		goto out;
+	}
+
+	byte_off = chunk_idx ? (chunk_idx - 1) * bytes_per_off : 0;
+	bytes_to_read = chunk_idx + 1 == chunk_count ?
+				bytes_per_off :
+				(chunk_idx ? 2 : 1) * bytes_per_off;
+
+	if (NInoNonResident(ni)) {
+		sector_t start_sector = byte_off >> 9;
+		u32 sector_off = byte_off & ((1 << 9) - 1);
+		u32 sectors = DIV_ROUND_UP(sector_off + bytes_to_read, 512);
+
+		if ((size_t)sectors << 9 > table_buf_size)
+			return -EINVAL;
+		buf = table_buf;
+		ret = ntfs_bdev_read_from_rl(ni->vol, &ni->runlist,
+					     start_sector, sectors, buf);
+		if (ret)
+			return -EIO;
+		buf += sector_off;
+	} else {
+		struct ntfs_attr_search_ctx *ctx;
+		u32 value_length;
+		u16 value_offset;
+
+		if (bytes_to_read > table_buf_size)
+			return -EINVAL;
+
+		mutex_lock(&base_ni->mrec_lock);
+		ctx = ntfs_attr_get_search_ctx(base_ni, NULL);
+		if (!ctx) {
+			ret = -ENOMEM;
+			goto out_unlock_mrec;
+		}
+		ret = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+				       CASE_SENSITIVE, 0, NULL, 0, ctx);
+		if (ret)
+			goto out_put_ctx;
+
+		value_length =
+			le32_to_cpu(ctx->attr->data.resident.value_length);
+		value_offset =
+			le16_to_cpu(ctx->attr->data.resident.value_offset);
+		if (byte_off + bytes_to_read > value_length) {
+			ret = -EINVAL;
+			goto out_put_ctx;
+		}
+		memcpy(table_buf, (u8 *)ctx->attr + value_offset + byte_off,
+		       bytes_to_read);
+		buf = table_buf;
+out_put_ctx:
+		ntfs_attr_put_search_ctx(ctx);
+out_unlock_mrec:
+		mutex_unlock(&base_ni->mrec_lock);
+		if (ret)
+			return ret;
+	}
+
+	if (bytes_per_off == sizeof(__le32)) {
+		off[0] = chunk_idx ? get_unaligned_le32(buf) : 0;
+		if (chunk_idx + 1 == chunk_count)
+			off[1] = chunk_data_size;
+		else if (chunk_idx)
+			off[1] = get_unaligned_le32(buf + bytes_per_off);
+		else
+			off[1] = get_unaligned_le32(buf);
+	} else {
+		off[0] = chunk_idx ? get_unaligned_le64(buf) : 0;
+		if (chunk_idx + 1 == chunk_count)
+			off[1] = chunk_data_size;
+		else if (chunk_idx)
+			off[1] = get_unaligned_le64(buf + bytes_per_off);
+		else
+			off[1] = get_unaligned_le64(buf);
+	}
+
+	if (off[1] <= off[0] || off[1] > chunk_data_size ||
+	    off[1] - off[0] > decomp_size)
+		return -EINVAL;
+
+	*chunk_offset = table_size + off[0];
+	*chunk_size = off[1] - off[0];
+out:
+	if (!*chunk_size)
+		return -EINVAL;
+	return 0;
+}
+
+static int ntfs_read_wof_chunk(struct ntfs_volume *vol,
+			       struct ntfs_inode *wof_ni, u64 chunk_offset,
+			       u32 chunk_size, void *input, size_t input_size,
+			       char **chunk_mem)
+{
+	struct ntfs_inode *base_ni = wof_ni->ext.base_ntfs_ino;
+	struct ntfs_attr_search_ctx *ctx;
+	u32 input_offset = chunk_offset & 511;
+	u32 input_size_aligned;
+	u32 value_length;
+	u16 value_offset;
+	int err;
+
+	input_size_aligned = round_up(chunk_size + input_offset, 512);
+	if (input_size_aligned > input_size)
+		return -EINVAL;
+
+	if (NInoNonResident(wof_ni)) {
+		err = ntfs_bdev_read_from_rl(vol, &wof_ni->runlist,
+					     chunk_offset >> 9,
+					     input_size_aligned >> 9, input);
+		if (err)
+			return err;
+		*chunk_mem = (u8 *)input + input_offset;
+		return 0;
+	}
+
+	mutex_lock(&base_ni->mrec_lock);
+	ctx = ntfs_attr_get_search_ctx(base_ni, NULL);
+	if (!ctx) {
+		err = -ENOMEM;
+		goto out_unlock_mrec;
+	}
+
+	err = ntfs_attr_lookup(wof_ni->type, wof_ni->name, wof_ni->name_len,
+			       CASE_SENSITIVE, 0, NULL, 0, ctx);
+	if (err)
+		goto out_put_ctx;
+
+	value_length = le32_to_cpu(ctx->attr->data.resident.value_length);
+	value_offset = le16_to_cpu(ctx->attr->data.resident.value_offset);
+	if (chunk_offset + chunk_size > value_length) {
+		err = -EINVAL;
+		goto out_put_ctx;
+	}
+	memcpy(input, (u8 *)ctx->attr + value_offset + chunk_offset,
+	       chunk_size);
+	*chunk_mem = input;
+out_put_ctx:
+	ntfs_attr_put_search_ctx(ctx);
+out_unlock_mrec:
+	mutex_unlock(&base_ni->mrec_lock);
+	return err;
+}
+
+struct ntfs_wof_dest {
+	struct folio *folios[NTFS_WOF_MAX_PAGES];
+	struct page *pages[NTFS_WOF_MAX_PAGES];
+	unsigned int nr_folios;
+	unsigned int nr_pages;
+};
+
+static void ntfs_wof_release_dest(struct ntfs_wof_dest *dest,
+				  struct folio *target, bool success)
+{
+	unsigned int i;
+
+	for (i = 0; i < dest->nr_folios; i++) {
+		struct folio *folio = dest->folios[i];
+
+		if (folio == target)
+			continue;
+		if (success) {
+			flush_dcache_folio(folio);
+			folio_mark_uptodate(folio);
+		} else {
+			folio_clear_uptodate(folio);
+		}
+		folio_unlock(folio);
+		folio_put(folio);
+	}
+}
+
+static int ntfs_wof_collect_dest(struct address_space *mapping,
+				 struct folio *target, loff_t chunk_start,
+				 loff_t chunk_end, struct ntfs_wof_dest *dest)
+{
+	pgoff_t index, last, page_index;
+	unsigned int i;
+
+	memset(dest, 0, sizeof(*dest));
+	index = chunk_start >> PAGE_SHIFT;
+	last = (chunk_end - 1) >> PAGE_SHIFT;
+	while (index <= last) {
+		struct folio *folio;
+		pgoff_t next;
+		bool is_target;
+
+		if (folio_contains(target, index)) {
+			folio = target;
+			is_target = true;
+		} else {
+			folio = __filemap_get_folio(
+				mapping, index,
+				FGP_LOCK | FGP_CREAT | FGP_NOFS | FGP_NOWAIT,
+				GFP_NOFS);
+			if (IS_ERR(folio))
+				return PTR_ERR(folio);
+			is_target = false;
+			if (folio_pos(folio) < chunk_start ||
+			    folio_next_pos(folio) > chunk_end) {
+				folio_unlock(folio);
+				folio_put(folio);
+				return -EAGAIN;
+			}
+		}
+
+		if (dest->nr_folios == ARRAY_SIZE(dest->folios)) {
+			if (!is_target) {
+				folio_unlock(folio);
+				folio_put(folio);
+			}
+			return -EINVAL;
+		}
+		dest->folios[dest->nr_folios++] = folio;
+		next = folio->index + folio_nr_pages(folio);
+		if (next <= index)
+			return -EAGAIN;
+		index = next;
+	}
+
+	for (page_index = chunk_start >> PAGE_SHIFT; page_index <= last;
+	     page_index++) {
+		struct folio *folio = NULL;
+
+		for (i = 0; i < dest->nr_folios; i++) {
+			if (folio_contains(dest->folios[i], page_index)) {
+				folio = dest->folios[i];
+				break;
+			}
+		}
+		if (!folio || dest->nr_pages == ARRAY_SIZE(dest->pages))
+			return -EAGAIN;
+		dest->pages[dest->nr_pages++] =
+			folio_page(folio, page_index - folio->index);
+	}
+	return 0;
+}
+
+static int ntfs_wof_decode(struct ntfs_wof_workspace *ws, const void *src,
+			   u32 src_len, void *dst, u32 dst_len)
+{
+	if (src_len == dst_len) {
+		memcpy(dst, src, dst_len);
+		return 0;
+	}
+	return ws->codec->decompress_chunk(ws->scratch, src, src_len, dst,
+					   dst_len, ws->comp_unit);
+}
+
+static int ntfs_wof_decode_page_direct(struct ntfs_wof_workspace *ws,
+				       struct folio *target, loff_t chunk_start,
+				       const void *src, u32 src_len,
+				       u32 dst_len)
+{
+	unsigned int page_offset = offset_in_page(chunk_start);
+	struct page *page;
+	pgoff_t page_index;
+	void *addr;
+	int err;
+
+	page_index = chunk_start >> PAGE_SHIFT;
+	if (!folio_contains(target, page_index))
+		return -EAGAIN;
+
+	page = folio_page(target, page_index - target->index);
+	addr = kmap_local_page(page);
+	err = ntfs_wof_decode(ws, src, src_len, (u8 *)addr + page_offset,
+			      dst_len);
+	kunmap_local(addr);
+	if (err)
+		return -EINVAL;
+	return 0;
+}
+
+static int ntfs_wof_decode_folios_direct(struct ntfs_wof_workspace *ws,
+					 struct address_space *mapping,
+					 struct folio *target,
+					 loff_t chunk_start, loff_t chunk_end,
+					 const void *src, u32 src_len,
+					 u32 dst_len)
+{
+	unsigned int page_offset = offset_in_page(chunk_start);
+	struct ntfs_wof_dest dest;
+	void *addr;
+	unsigned int nofs_flags;
+	int err;
+
+	err = ntfs_wof_collect_dest(mapping, target, chunk_start, chunk_end,
+				    &dest);
+	if (err) {
+		ntfs_wof_release_dest(&dest, target, false);
+		return -EAGAIN;
+	}
+
+	nofs_flags = memalloc_nofs_save();
+	addr = vmap(dest.pages, dest.nr_pages, VM_MAP, PAGE_KERNEL);
+	memalloc_nofs_restore(nofs_flags);
+	if (!addr) {
+		ntfs_wof_release_dest(&dest, target, false);
+		return -EAGAIN;
+	}
+
+	err = ntfs_wof_decode(ws, src, src_len, (u8 *)addr + page_offset,
+			      dst_len);
+	vunmap(addr);
+	if (err) {
+		ntfs_wof_release_dest(&dest, target, false);
+		return -EINVAL;
+	}
+	ntfs_wof_release_dest(&dest, target, true);
+	return 0;
+}
+
+static int ntfs_wof_try_direct(struct ntfs_wof_workspace *ws,
+			       struct address_space *mapping,
+			       struct folio *target, loff_t chunk_start,
+			       loff_t chunk_end, const void *src, u32 src_len,
+			       u32 dst_len)
+{
+	unsigned int page_offset = offset_in_page(chunk_start);
+
+	if (dst_len <= PAGE_SIZE - page_offset)
+		return ntfs_wof_decode_page_direct(ws, target, chunk_start, src,
+						   src_len, dst_len);
+
+	return ntfs_wof_decode_folios_direct(ws, mapping, target, chunk_start,
+					     chunk_end, src, src_len, dst_len);
+}
+
+int ntfs_read_wof_compressed_block(struct folio *folio)
+{
+	struct address_space *mapping = folio->mapping;
+	struct ntfs_inode *ni = NTFS_I(mapping->host), *wof_ni;
+	struct inode *wof_inode;
+	struct ntfs_volume *vol = ni->vol;
+	struct ntfs_wof_workspace *ws;
+	loff_t i_size = i_size_read(VFS_I(ni));
+	loff_t folio_start = folio_pos(folio);
+	loff_t folio_end = folio_next_pos(folio);
+	char *chunk_mem;
+	u32 decomp_size;
+	u64 chunk_count, chunk_idx, last_chunk, chunk_offset;
+	int err = 0;
+
+	ws = ntfs_wof_workspace(ni->itype.compressed.block_size_bits);
+	if (!ws) {
+		err = -EOPNOTSUPP;
+		goto out;
+	}
+
+	if (folio_start >= i_size) {
+		folio_zero_segment(folio, 0, folio_size(folio));
+		goto out;
+	}
+
+	wof_inode = ntfs_attr_iget(VFS_I(ni), AT_DATA, (__le16 *)WOF_NAME,
+				   WOF_NAME_LEN);
+	if (IS_ERR(wof_inode)) {
+		err = PTR_ERR(wof_inode);
+		goto out;
+	}
+
+	wof_ni = NTFS_I(wof_inode);
+	if (wof_ni->initialized_size != wof_ni->data_size) {
+		ntfs_error(vol->sb,
+			   "WOF compressed stream is not fully initialized (init %lld, data %lld).",
+			   wof_ni->initialized_size, wof_ni->data_size);
+		err = -EIO;
+		goto out_iput;
+	}
+	if (NInoNonResident(wof_ni) && !NInoFullyMapped(wof_ni)) {
+		down_write(&wof_ni->runlist.lock);
+		if (!NInoFullyMapped(wof_ni))
+			err = ntfs_attr_map_whole_runlist(wof_ni);
+		up_write(&wof_ni->runlist.lock);
+		if (err)
+			goto out_iput;
+	}
+
+	mutex_lock(ws->lock);
+	err = ntfs_wof_workspace_prepare(ws);
+	if (err)
+		goto out_unlock_ws;
+
+	chunk_idx = div_u64(folio_start, ws->comp_unit);
+	last_chunk =
+		div_u64(min_t(loff_t, folio_end, i_size) - 1, ws->comp_unit);
+	chunk_count = DIV_ROUND_UP_ULL(i_size, ws->comp_unit);
+	for (; chunk_idx <= last_chunk; chunk_idx++) {
+		u32 chunk_size;
+		u64 chunk_file_offset;
+		loff_t chunk_end, copy_start, copy_end;
+
+		decomp_size = chunk_idx + 1 == chunk_count ?
+				      i_size - chunk_idx * ws->comp_unit :
+				      ws->comp_unit;
+		err = parse_wof_chunk_table(ni, wof_ni, chunk_idx, chunk_count,
+					    decomp_size, &chunk_offset,
+					    &chunk_size, ws->input,
+					    ws->input_size);
+		if (err)
+			goto out_unlock_ws;
+
+		err = ntfs_read_wof_chunk(vol, wof_ni, chunk_offset, chunk_size,
+					  ws->input, ws->input_size,
+					  &chunk_mem);
+		if (err)
+			goto out_unlock_ws;
+
+		chunk_file_offset = chunk_idx * ws->comp_unit;
+		chunk_end = chunk_file_offset + decomp_size;
+		err = ntfs_wof_try_direct(ws, mapping, folio, chunk_file_offset,
+					  chunk_end, chunk_mem, chunk_size,
+					  decomp_size);
+		if (!err)
+			continue;
+		if (err != -EAGAIN)
+			goto out_unlock_ws;
+
+		err = ntfs_wof_decode(ws, chunk_mem, chunk_size, ws->output,
+				      decomp_size);
+		if (err) {
+			ntfs_error(vol->sb, "Decompression failed: %d", err);
+			err = -EINVAL;
+			goto out_unlock_ws;
+		}
+		copy_start = max_t(loff_t, folio_start, chunk_file_offset);
+		copy_end = min_t(loff_t, folio_end,
+				 chunk_file_offset + decomp_size);
+		memcpy_to_folio(folio, copy_start - folio_start,
+				ws->output + copy_start - chunk_file_offset,
+				copy_end - copy_start);
+	}
+
+	if (folio_end > i_size)
+		folio_zero_segment(folio, i_size - folio_start,
+				   folio_size(folio));
+out_unlock_ws:
+	mutex_unlock(ws->lock);
+out_iput:
+	iput(wof_inode);
+out:
+	if (!err) {
+		flush_dcache_folio(folio);
+		folio_mark_uptodate(folio);
+	} else {
+		folio_clear_uptodate(folio);
+	}
+	folio_unlock(folio);
+	return err;
+}