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Subject[PATCH 5.15 067/171] ocfs2: fix a deadlock when commit trans
Date
From: Joseph Qi <joseph.qi@linux.alibaba.com>

commit ddf4b773aa40790dfa936bd845c18e735a49c61c upstream.

commit 6f1b228529ae introduces a regression which can deadlock as
follows:

Task1: Task2:
jbd2_journal_commit_transaction ocfs2_test_bg_bit_allocatable
spin_lock(&jh->b_state_lock) jbd_lock_bh_journal_head
__jbd2_journal_remove_checkpoint spin_lock(&jh->b_state_lock)
jbd2_journal_put_journal_head
jbd_lock_bh_journal_head

Task1 and Task2 lock bh->b_state and jh->b_state_lock in different
order, which finally result in a deadlock.

So use jbd2_journal_[grab|put]_journal_head instead in
ocfs2_test_bg_bit_allocatable() to fix it.

Link: https://lkml.kernel.org/r/20220121071205.100648-3-joseph.qi@linux.alibaba.com
Fixes: 6f1b228529ae ("ocfs2: fix race between searching chunks and release journal_head from buffer_head")
Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reported-by: Gautham Ananthakrishna <gautham.ananthakrishna@oracle.com>
Tested-by: Gautham Ananthakrishna <gautham.ananthakrishna@oracle.com>
Reported-by: Saeed Mirzamohammadi <saeed.mirzamohammadi@oracle.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Jun Piao <piaojun@huawei.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/ocfs2/suballoc.c | 25 +++++++++++--------------
1 file changed, 11 insertions(+), 14 deletions(-)

--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -1251,26 +1251,23 @@ static int ocfs2_test_bg_bit_allocatable
{
struct ocfs2_group_desc *bg = (struct ocfs2_group_desc *) bg_bh->b_data;
struct journal_head *jh;
- int ret = 1;
+ int ret;

if (ocfs2_test_bit(nr, (unsigned long *)bg->bg_bitmap))
return 0;

- if (!buffer_jbd(bg_bh))
+ jh = jbd2_journal_grab_journal_head(bg_bh);
+ if (!jh)
return 1;

- jbd_lock_bh_journal_head(bg_bh);
- if (buffer_jbd(bg_bh)) {
- jh = bh2jh(bg_bh);
- spin_lock(&jh->b_state_lock);
- bg = (struct ocfs2_group_desc *) jh->b_committed_data;
- if (bg)
- ret = !ocfs2_test_bit(nr, (unsigned long *)bg->bg_bitmap);
- else
- ret = 1;
- spin_unlock(&jh->b_state_lock);
- }
- jbd_unlock_bh_journal_head(bg_bh);
+ spin_lock(&jh->b_state_lock);
+ bg = (struct ocfs2_group_desc *) jh->b_committed_data;
+ if (bg)
+ ret = !ocfs2_test_bit(nr, (unsigned long *)bg->bg_bitmap);
+ else
+ ret = 1;
+ spin_unlock(&jh->b_state_lock);
+ jbd2_journal_put_journal_head(jh);

return ret;
}

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