The patch titled
Subject: ocfs2: fix a deadlock when commit trans
has been added to the -mm tree. Its filename is
ocfs2-fix-a-deadlock-when-commit-trans.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/ocfs2-fix-a-deadlock-when-commit-trans.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/ocfs2-fix-a-deadlock-when-commit-trans.patch
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------------------------------------------------------
From: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
Subject: ocfs2: fix a deadlock when commit trans
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@xxxxxxxxxxxxxxxxx
Fixes: 6f1b228529ae ("ocfs2: fix race between searching chunks and release journal_head from buffer_head")
Signed-off-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
Reported-by: Gautham Ananthakrishna <gautham.ananthakrishna@xxxxxxxxxx>
Reported-by: Saeed Mirzamohammadi <saeed.mirzamohammadi@xxxxxxxxxx>
Cc: "Theodore Ts'o" <tytso@xxxxxxx>
Cc: Andreas Dilger <adilger.kernel@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Cc: Changwei Ge <gechangwei@xxxxxxx>
Cc: Gang He <ghe@xxxxxxxx>
Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
Cc: Jun Piao <piaojun@xxxxxxxxxx>
Cc: Junxiao Bi <junxiao.bi@xxxxxxxxxx>
Cc: Mark Fasheh <mark@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ocfs2/suballoc.c | 25 +++++++++++--------------
1 file changed, 11 insertions(+), 14 deletions(-)
--- a/fs/ocfs2/suballoc.c~ocfs2-fix-a-deadlock-when-commit-trans
+++ a/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;
}
_
Patches currently in -mm which might be from joseph.qi@xxxxxxxxxxxxxxxxx are
jbd2-export-jbd2_journal__journal_head.patch
ocfs2-fix-a-deadlock-when-commit-trans.patch
