From e8a8522080eb5014f6228a8cd75e21853f3ad927 Mon Sep 17 00:00:00 2001 From: Ojaswin Mujoo Date: Thu, 21 Nov 2024 18:08:55 +0530 Subject: [PATCH] ext4: protect ext4_release_dquot against freezing [ Upstream commit 530fea29ef82e169cd7fe048c2b7baaeb85a0028 ] Protect ext4_release_dquot against freezing so that we don't try to start a transaction when FS is frozen, leading to warnings. Further, avoid taking the freeze protection if a transaction is already running so that we don't need end up in a deadlock as described in 46e294efc355 ext4: fix deadlock with fs freezing and EA inodes Suggested-by: Jan Kara Signed-off-by: Ojaswin Mujoo Reviewed-by: Baokun Li Reviewed-by: Jan Kara Link: https://patch.msgid.link/20241121123855.645335-3-ojaswin@linux.ibm.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin --- fs/ext4/super.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 20e89ffe9a06..1e60d957b7c1 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -6251,12 +6251,25 @@ static int ext4_release_dquot(struct dquot *dquot) { int ret, err; handle_t *handle; + bool freeze_protected = false; + + /* + * Trying to sb_start_intwrite() in a running transaction + * can result in a deadlock. Further, running transactions + * are already protected from freezing. + */ + if (!ext4_journal_current_handle()) { + sb_start_intwrite(dquot->dq_sb); + freeze_protected = true; + } handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA, EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb)); if (IS_ERR(handle)) { /* Release dquot anyway to avoid endless cycle in dqput() */ dquot_release(dquot); + if (freeze_protected) + sb_end_intwrite(dquot->dq_sb); return PTR_ERR(handle); } ret = dquot_release(dquot); @@ -6267,6 +6280,10 @@ static int ext4_release_dquot(struct dquot *dquot) err = ext4_journal_stop(handle); if (!ret) ret = err; + + if (freeze_protected) + sb_end_intwrite(dquot->dq_sb); + return ret; }