linux-stable.git/fs/jbd2, branch v6.17

jbd2: prevent softlockup in jbd2_log_do_checkpoint()

2025-08-13T18:24:14+00:00

Both jbd2_log_do_checkpoint() and jbd2_journal_shrink_checkpoint_list()
periodically release j_list_lock after processing a batch of buffers to
avoid long hold times on the j_list_lock. However, since both functions
contend for j_list_lock, the combined time spent waiting and processing
can be significant.

jbd2_journal_shrink_checkpoint_list() explicitly calls cond_resched() when
need_resched() is true to avoid softlockups during prolonged operations.
But jbd2_log_do_checkpoint() only exits its loop when need_resched() is
true, relying on potentially sleeping functions like __flush_batch() or
wait_on_buffer() to trigger rescheduling. If those functions do not sleep,
the kernel may hit a softlockup.

watchdog: BUG: soft lockup - CPU#3 stuck for 156s! [kworker/u129:2:373]
CPU: 3 PID: 373 Comm: kworker/u129:2 Kdump: loaded Not tainted 6.6.0+ #10
Hardware name: Huawei TaiShan 2280 /BC11SPCD, BIOS 1.27 06/13/2017
Workqueue: writeback wb_workfn (flush-7:2)
pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : native_queued_spin_lock_slowpath+0x358/0x418
lr : jbd2_log_do_checkpoint+0x31c/0x438 [jbd2]
Call trace:
 native_queued_spin_lock_slowpath+0x358/0x418
 jbd2_log_do_checkpoint+0x31c/0x438 [jbd2]
 __jbd2_log_wait_for_space+0xfc/0x2f8 [jbd2]
 add_transaction_credits+0x3bc/0x418 [jbd2]
 start_this_handle+0xf8/0x560 [jbd2]
 jbd2__journal_start+0x118/0x228 [jbd2]
 __ext4_journal_start_sb+0x110/0x188 [ext4]
 ext4_do_writepages+0x3dc/0x740 [ext4]
 ext4_writepages+0xa4/0x190 [ext4]
 do_writepages+0x94/0x228
 __writeback_single_inode+0x48/0x318
 writeback_sb_inodes+0x204/0x590
 __writeback_inodes_wb+0x54/0xf8
 wb_writeback+0x2cc/0x3d8
 wb_do_writeback+0x2e0/0x2f8
 wb_workfn+0x80/0x2a8
 process_one_work+0x178/0x3e8
 worker_thread+0x234/0x3b8
 kthread+0xf0/0x108
 ret_from_fork+0x10/0x20

So explicitly call cond_resched() in jbd2_log_do_checkpoint() to avoid
softlockup.

Cc: stable@kernel.org
Signed-off-by: Baokun Li 
Link: https://patch.msgid.link/20250812063752.912130-1-libaokun@huaweicloud.com
Signed-off-by: Theodore Ts'o

treewide, timers: Rename from_timer() to timer_container_of()

2025-06-08T07:07:37+00:00

Move this API to the canonical timer_*() namespace.

[ tglx: Redone against pre rc1 ]

Signed-off-by: Ingo Molnar 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/all/aB2X0jCKQO56WdMt@gmail.com

jbd2: remove journal_t argument from jbd2_superblock_csum()

2025-05-20T14:31:12+00:00

Since jbd2_superblock_csum() no longer uses its journal_t argument,
remove it.

Signed-off-by: Eric Biggers 
Reviewed-by: Baokun Li 
Link: https://patch.msgid.link/20250513053809.699974-5-ebiggers@kernel.org
Signed-off-by: Theodore Ts'o

jbd2: remove journal_t argument from jbd2_chksum()

2025-05-20T14:31:12+00:00

Since jbd2_chksum() no longer uses its journal_t argument, remove it.

Signed-off-by: Eric Biggers 
Reviewed-by: Baokun Li 
Link: https://patch.msgid.link/20250513053809.699974-4-ebiggers@kernel.org
Signed-off-by: Theodore Ts'o

ext4/jbd2: convert jbd2_journal_blocks_per_page() to support large folio

2025-05-20T14:31:12+00:00

jbd2_journal_blocks_per_page() returns the number of blocks in a single
page. Rename it to jbd2_journal_blocks_per_folio() and make it returns
the number of blocks in the largest folio, preparing for the calculation
of journal credits blocks when allocating blocks within a large folio in
the writeback path.

Signed-off-by: Zhang Yi 
Link: https://patch.msgid.link/20250512063319.3539411-5-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o

jbd2: fix data-race and null-ptr-deref in jbd2_journal_dirty_metadata()

2025-05-20T14:30:37+00:00

Since handle->h_transaction may be a NULL pointer, so we should change it
to call is_handle_aborted(handle) first before dereferencing it.

And the following data-race was reported in my fuzzer:

==================================================================
BUG: KCSAN: data-race in jbd2_journal_dirty_metadata / jbd2_journal_dirty_metadata

write to 0xffff888011024104 of 4 bytes by task 10881 on cpu 1:
 jbd2_journal_dirty_metadata+0x2a5/0x770 fs/jbd2/transaction.c:1556
 __ext4_handle_dirty_metadata+0xe7/0x4b0 fs/ext4/ext4_jbd2.c:358
 ext4_do_update_inode fs/ext4/inode.c:5220 [inline]
 ext4_mark_iloc_dirty+0x32c/0xd50 fs/ext4/inode.c:5869
 __ext4_mark_inode_dirty+0xe1/0x450 fs/ext4/inode.c:6074
 ext4_dirty_inode+0x98/0xc0 fs/ext4/inode.c:6103
....

read to 0xffff888011024104 of 4 bytes by task 10880 on cpu 0:
 jbd2_journal_dirty_metadata+0xf2/0x770 fs/jbd2/transaction.c:1512
 __ext4_handle_dirty_metadata+0xe7/0x4b0 fs/ext4/ext4_jbd2.c:358
 ext4_do_update_inode fs/ext4/inode.c:5220 [inline]
 ext4_mark_iloc_dirty+0x32c/0xd50 fs/ext4/inode.c:5869
 __ext4_mark_inode_dirty+0xe1/0x450 fs/ext4/inode.c:6074
 ext4_dirty_inode+0x98/0xc0 fs/ext4/inode.c:6103
....

value changed: 0x00000000 -> 0x00000001
==================================================================

This issue is caused by missing data-race annotation for jh->b_modified.
Therefore, the missing annotation needs to be added.

Reported-by: syzbot+de24c3fe3c4091051710@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=de24c3fe3c4091051710
Fixes: 6e06ae88edae ("jbd2: speedup jbd2_journal_dirty_metadata()")
Signed-off-by: Jeongjun Park 
Reviewed-by: Jan Kara 
Link: https://patch.msgid.link/20250514130855.99010-1-aha310510@gmail.com
Signed-off-by: Theodore Ts'o 
Cc: stable@kernel.org

ext4: rework fast commit commit path

2025-05-09T01:56:17+00:00

This patch reworks fast commit's commit path to remove locking the
journal for the entire duration of a fast commit. Instead, we only lock
the journal while marking all the eligible inodes as "committing". This
allows handles to make progress in parallel with the fast commit.

Signed-off-by: Harshad Shirwadkar 
Link: https://patch.msgid.link/20250508175908.1004880-5-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o

fs/jbd2: use sleeping version of __find_get_block()

2025-04-22T16:16:08+00:00

Convert to the new nonatomic flavor to benefit from potential
performance benefits and adapt in the future vs migration such
that semantics are kept.

- jbd2_journal_revoke(): can sleep (has might_sleep() in the beginning)

- jbd2_journal_cancel_revoke(): only used from do_get_write_access() and
    do_get_create_access() which do sleep. So can sleep.

- jbd2_clear_buffer_revoked_flags() - only called from journal commit code
    which sleeps. So can sleep.

Suggested-by: Jan Kara 
Reviewed-by: Jan Kara 
Signed-off-by: Davidlohr Bueso 
Link: https://kdevops.org/ext4/v6.15-rc2.html # [0]
Link: https://lore.kernel.org/all/aAAEvcrmREWa1SKF@bombadil.infradead.org/ # [1]
Link: https://lore.kernel.org/20250418015921.132400-6-dave@stgolabs.net
Tested-by: kdevops@lists.linux.dev
Reviewed-by: Luis Chamberlain 
Signed-off-by: Christian Brauner

treewide: Switch/rename to timer_delete[_sync]()

2025-04-05T08:30:12+00:00

timer_delete[_sync]() replaces del_timer[_sync](). Convert the whole tree
over and remove the historical wrapper inlines.

Conversion was done with coccinelle plus manual fixups where necessary.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Ingo Molnar

jbd2: add a missing data flush during file and fs synchronization

2025-03-21T04:59:28+00:00

When the filesystem performs file or filesystem synchronization (e.g.,
ext4_sync_file()), it queries the journal to determine whether to flush
the file device through jbd2_trans_will_send_data_barrier(). If the
target transaction has not started committing, it assumes that the
journal will submit the flush command, allowing the filesystem to bypass
a redundant flush command. However, this assumption is not always valid.
If the journal is not located on the filesystem device, the journal
commit thread will not submit the flush command unless the variable
->t_need_data_flush is set to 1. Consequently, the flush may be missed,
and data may be lost following a power failure or system crash, even if
the synchronization appears to succeed.

Unfortunately, we cannot determine with certainty whether the target
transaction will flush to the filesystem device before it commits.
However, if it has not started committing, it must be the running
transaction. Therefore, fix it by always set its t_need_data_flush to 1,
ensuring that the committing thread will flush the filesystem device.

Fixes: bbd2be369107 ("jbd2: Add function jbd2_trans_will_send_data_barrier()")
Signed-off-by: Zhang Yi 
Reviewed-by: Jan Kara 
Link: https://patch.msgid.link/20241206111327.4171337-1-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o