6.6-stable review patch. If anyone has any objections, please let me know.
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From: Long Li leo.lilong@huawei.com
[ Upstream commit 2f3d93e210b9c2866c8b3662adae427d5bf511ec ]
When I enabled ext4 debug for fault injection testing, I encountered the following warning:
EXT4-fs error (device sda): ext4_read_inode_bitmap:201: comm fsstress: Cannot read inode bitmap - block_group = 8, inode_bitmap = 1051 WARNING: CPU: 0 PID: 511 at fs/buffer.c:1181 mark_buffer_dirty+0x1b3/0x1d0
The root cause of the issue lies in the improper implementation of ext4's buffer_head read fault injection. The actual completion of buffer_head read and the buffer_head fault injection are not atomic, which can lead to the uptodate flag being cleared on normally used buffer_heads in race conditions.
[CPU0] [CPU1] [CPU2] ext4_read_inode_bitmap ext4_read_bh() <bh read complete> ext4_read_inode_bitmap if (buffer_uptodate(bh)) return bh jbd2_journal_commit_transaction __jbd2_journal_refile_buffer __jbd2_journal_unfile_buffer __jbd2_journal_temp_unlink_buffer ext4_simulate_fail_bh() clear_buffer_uptodate mark_buffer_dirty <report warning> WARN_ON_ONCE(!buffer_uptodate(bh))
The best approach would be to perform fault injection in the IO completion callback function, rather than after IO completion. However, the IO completion callback function cannot get the fault injection code in sb.
Fix it by passing the result of fault injection into the bh read function, we simulate faults within the bh read function itself. This requires adding an extra parameter to the bh read functions that need fault injection.
Fixes: 46f870d690fe ("ext4: simulate various I/O and checksum errors when reading metadata") Signed-off-by: Long Li leo.lilong@huawei.com Link: https://patch.msgid.link/20240906091746.510163-1-leo.lilong@huawei.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ext4/balloc.c | 4 ++-- fs/ext4/ext4.h | 12 ++---------- fs/ext4/extents.c | 2 +- fs/ext4/ialloc.c | 5 +++-- fs/ext4/indirect.c | 2 +- fs/ext4/inode.c | 4 ++-- fs/ext4/mmp.c | 2 +- fs/ext4/move_extent.c | 2 +- fs/ext4/resize.c | 2 +- fs/ext4/super.c | 23 +++++++++++++++-------- 10 files changed, 29 insertions(+), 29 deletions(-)
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c index 79b20d6ae39ec..396474e9e2bff 100644 --- a/fs/ext4/balloc.c +++ b/fs/ext4/balloc.c @@ -545,7 +545,8 @@ ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group, trace_ext4_read_block_bitmap_load(sb, block_group, ignore_locked); ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO | (ignore_locked ? REQ_RAHEAD : 0), - ext4_end_bitmap_read); + ext4_end_bitmap_read, + ext4_simulate_fail(sb, EXT4_SIM_BBITMAP_EIO)); return bh; verify: err = ext4_validate_block_bitmap(sb, desc, block_group, bh); @@ -569,7 +570,6 @@ int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group, if (!desc) return -EFSCORRUPTED; wait_on_buffer(bh); - ext4_simulate_fail_bh(sb, bh, EXT4_SIM_BBITMAP_EIO); if (!buffer_uptodate(bh)) { ext4_error_err(sb, EIO, "Cannot read block bitmap - " "block_group = %u, block_bitmap = %llu", diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 7bbf0b9bdff23..3db01b933c3e8 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1849,14 +1849,6 @@ static inline bool ext4_simulate_fail(struct super_block *sb, return false; }
-static inline void ext4_simulate_fail_bh(struct super_block *sb, - struct buffer_head *bh, - unsigned long code) -{ - if (!IS_ERR(bh) && ext4_simulate_fail(sb, code)) - clear_buffer_uptodate(bh); -} - /* * Error number codes for s_{first,last}_error_errno * @@ -3072,9 +3064,9 @@ extern struct buffer_head *ext4_sb_bread(struct super_block *sb, extern struct buffer_head *ext4_sb_bread_unmovable(struct super_block *sb, sector_t block); extern void ext4_read_bh_nowait(struct buffer_head *bh, blk_opf_t op_flags, - bh_end_io_t *end_io); + bh_end_io_t *end_io, bool simu_fail); extern int ext4_read_bh(struct buffer_head *bh, blk_opf_t op_flags, - bh_end_io_t *end_io); + bh_end_io_t *end_io, bool simu_fail); extern int ext4_read_bh_lock(struct buffer_head *bh, blk_opf_t op_flags, bool wait); extern void ext4_sb_breadahead_unmovable(struct super_block *sb, sector_t block); extern int ext4_seq_options_show(struct seq_file *seq, void *offset); diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 1c059ac1c1ef2..5ea75af6ca223 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -564,7 +564,7 @@ __read_extent_tree_block(const char *function, unsigned int line,
if (!bh_uptodate_or_lock(bh)) { trace_ext4_ext_load_extent(inode, pblk, _RET_IP_); - err = ext4_read_bh(bh, 0, NULL); + err = ext4_read_bh(bh, 0, NULL, false); if (err < 0) goto errout; } diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index 1a1e2214c581f..d4d0ad689d3c1 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -194,8 +194,9 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group) * submit the buffer_head for reading */ trace_ext4_load_inode_bitmap(sb, block_group); - ext4_read_bh(bh, REQ_META | REQ_PRIO, ext4_end_bitmap_read); - ext4_simulate_fail_bh(sb, bh, EXT4_SIM_IBITMAP_EIO); + ext4_read_bh(bh, REQ_META | REQ_PRIO, + ext4_end_bitmap_read, + ext4_simulate_fail(sb, EXT4_SIM_IBITMAP_EIO)); if (!buffer_uptodate(bh)) { put_bh(bh); ext4_error_err(sb, EIO, "Cannot read inode bitmap - " diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c index a9f3716119d37..f2c495b745f1e 100644 --- a/fs/ext4/indirect.c +++ b/fs/ext4/indirect.c @@ -170,7 +170,7 @@ static Indirect *ext4_get_branch(struct inode *inode, int depth, }
if (!bh_uptodate_or_lock(bh)) { - if (ext4_read_bh(bh, 0, NULL) < 0) { + if (ext4_read_bh(bh, 0, NULL, false) < 0) { put_bh(bh); goto failure; } diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 14f7098bcefe1..18ec9106c5b09 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4508,10 +4508,10 @@ static int __ext4_get_inode_loc(struct super_block *sb, unsigned long ino, * Read the block from disk. */ trace_ext4_load_inode(sb, ino); - ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO, NULL); + ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO, NULL, + ext4_simulate_fail(sb, EXT4_SIM_INODE_EIO)); blk_finish_plug(&plug); wait_on_buffer(bh); - ext4_simulate_fail_bh(sb, bh, EXT4_SIM_INODE_EIO); if (!buffer_uptodate(bh)) { if (ret_block) *ret_block = block; diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c index bd946d0c71b70..d64c04ed061ae 100644 --- a/fs/ext4/mmp.c +++ b/fs/ext4/mmp.c @@ -94,7 +94,7 @@ static int read_mmp_block(struct super_block *sb, struct buffer_head **bh, }
lock_buffer(*bh); - ret = ext4_read_bh(*bh, REQ_META | REQ_PRIO, NULL); + ret = ext4_read_bh(*bh, REQ_META | REQ_PRIO, NULL, false); if (ret) goto warn_exit;
diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c index f082bccdb01ad..5e6b07b349600 100644 --- a/fs/ext4/move_extent.c +++ b/fs/ext4/move_extent.c @@ -214,7 +214,7 @@ static int mext_page_mkuptodate(struct folio *folio, size_t from, size_t to) unlock_buffer(bh); continue; } - ext4_read_bh_nowait(bh, 0, NULL); + ext4_read_bh_nowait(bh, 0, NULL, false); nr++; } /* No io required */ diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c index 5f105171df7b5..b34007541e08c 100644 --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -1301,7 +1301,7 @@ static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block) if (unlikely(!bh)) return NULL; if (!bh_uptodate_or_lock(bh)) { - if (ext4_read_bh(bh, 0, NULL) < 0) { + if (ext4_read_bh(bh, 0, NULL, false) < 0) { brelse(bh); return NULL; } diff --git a/fs/ext4/super.c b/fs/ext4/super.c index c7dc14af6438a..04b0ad21fad27 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -161,8 +161,14 @@ MODULE_ALIAS("ext3");
static inline void __ext4_read_bh(struct buffer_head *bh, blk_opf_t op_flags, - bh_end_io_t *end_io) + bh_end_io_t *end_io, bool simu_fail) { + if (simu_fail) { + clear_buffer_uptodate(bh); + unlock_buffer(bh); + return; + } + /* * buffer's verified bit is no longer valid after reading from * disk again due to write out error, clear it to make sure we @@ -176,7 +182,7 @@ static inline void __ext4_read_bh(struct buffer_head *bh, blk_opf_t op_flags, }
void ext4_read_bh_nowait(struct buffer_head *bh, blk_opf_t op_flags, - bh_end_io_t *end_io) + bh_end_io_t *end_io, bool simu_fail) { BUG_ON(!buffer_locked(bh));
@@ -184,10 +190,11 @@ void ext4_read_bh_nowait(struct buffer_head *bh, blk_opf_t op_flags, unlock_buffer(bh); return; } - __ext4_read_bh(bh, op_flags, end_io); + __ext4_read_bh(bh, op_flags, end_io, simu_fail); }
-int ext4_read_bh(struct buffer_head *bh, blk_opf_t op_flags, bh_end_io_t *end_io) +int ext4_read_bh(struct buffer_head *bh, blk_opf_t op_flags, + bh_end_io_t *end_io, bool simu_fail) { BUG_ON(!buffer_locked(bh));
@@ -196,7 +203,7 @@ int ext4_read_bh(struct buffer_head *bh, blk_opf_t op_flags, bh_end_io_t *end_io return 0; }
- __ext4_read_bh(bh, op_flags, end_io); + __ext4_read_bh(bh, op_flags, end_io, simu_fail);
wait_on_buffer(bh); if (buffer_uptodate(bh)) @@ -208,10 +215,10 @@ int ext4_read_bh_lock(struct buffer_head *bh, blk_opf_t op_flags, bool wait) { lock_buffer(bh); if (!wait) { - ext4_read_bh_nowait(bh, op_flags, NULL); + ext4_read_bh_nowait(bh, op_flags, NULL, false); return 0; } - return ext4_read_bh(bh, op_flags, NULL); + return ext4_read_bh(bh, op_flags, NULL, false); }
/* @@ -259,7 +266,7 @@ void ext4_sb_breadahead_unmovable(struct super_block *sb, sector_t block)
if (likely(bh)) { if (trylock_buffer(bh)) - ext4_read_bh_nowait(bh, REQ_RAHEAD, NULL); + ext4_read_bh_nowait(bh, REQ_RAHEAD, NULL, false); brelse(bh); } }