From: Ojaswin Mujoo ojaswin@linux.ibm.com
[ 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 jack@suse.cz Signed-off-by: Ojaswin Mujoo ojaswin@linux.ibm.com Reviewed-by: Baokun Li libaokun1@huawei.com Reviewed-by: Jan Kara jack@suse.cz Link: https://patch.msgid.link/20241121123855.645335-3-ojaswin@linux.ibm.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ext4/super.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 9d7800d66200e..be4d863da0ebc 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -6244,12 +6244,25 @@ 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); @@ -6260,6 +6273,10 @@ 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; }