From: Joseph Qi joseph.qi@linux.alibaba.com 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@linux.alibaba.co... 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 ---
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; } _