From: Joseph Qi via Ocfs2-devel <ocfs2-devel@oss.oracle.com>
To: akpm@linux-foundation.org, tytso@mit.edu, adilger.kernel@dilger.ca
Cc: linux-ext4@vger.kernel.org, gautham.ananthakrishna@oracle.com,
ocfs2-devel@oss.oracle.com
Subject: [Ocfs2-devel] [PATCH 2/2] ocfs2: fix a deadlock when commit trans
Date: Fri, 21 Jan 2022 15:12:05 +0800 [thread overview]
Message-ID: <20220121071205.100648-3-joseph.qi@linux.alibaba.com> (raw)
In-Reply-To: <20220121071205.100648-1-joseph.qi@linux.alibaba.com>
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.
Reported-by: Gautham Ananthakrishna <gautham.ananthakrishna@oracle.com>
Fixes: 6f1b228529ae ("ocfs2: fix race between searching chunks and release journal_head from buffer_head")
Cc: <stable@vger.kernel.org>
Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
---
fs/ocfs2/suballoc.c | 25 +++++++++++--------------
1 file changed, 11 insertions(+), 14 deletions(-)
diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index 481017e1dac5..166c8918c825 100644
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -1251,26 +1251,23 @@ static int ocfs2_test_bg_bit_allocatable(struct buffer_head *bg_bh,
{
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;
}
--
2.19.1.6.gb485710b
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next prev parent reply other threads:[~2022-01-21 7:12 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-21 7:12 [Ocfs2-devel] [PATCH 0/2] ocfs2: fix a deadlock case Joseph Qi via Ocfs2-devel
2022-01-21 7:12 ` [Ocfs2-devel] [PATCH 1/2] jbd2: export jbd2_journal_[grab|put]_journal_head Joseph Qi via Ocfs2-devel
2022-01-21 7:12 ` Joseph Qi via Ocfs2-devel [this message]
2022-01-23 5:31 ` [Ocfs2-devel] [PATCH 2/2] ocfs2: fix a deadlock when commit trans Gautham Ananthakrishna via Ocfs2-devel
2022-01-24 2:37 ` Joseph Qi via Ocfs2-devel
2022-01-27 12:46 ` Gautham Ananthakrishna via Ocfs2-devel
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