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ext4: protect ext4_release_dquot against freezing

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[ 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

  46e294efc3 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>
This commit is contained in:
Ojaswin Mujoo
2024-11-21 18:08:55 +05:30
committed by Greg Kroah-Hartman
parent 1263713795
commit 1dbece9c2f
1 changed files with 17 additions and 0 deletions
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17
fs/ext4/super.c
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@@ -6933,12 +6933,25 @@ static int ext4_release_dquot(struct dquot *dquot)
{ {
int ret, err; int ret, err;
handle_t *handle; 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, handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA,
EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb)); EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb));
if (IS_ERR(handle)) { if (IS_ERR(handle)) {
/* Release dquot anyway to avoid endless cycle in dqput() */ /* Release dquot anyway to avoid endless cycle in dqput() */
dquot_release(dquot); dquot_release(dquot);
if (freeze_protected)
sb_end_intwrite(dquot->dq_sb);
return PTR_ERR(handle); return PTR_ERR(handle);
} }
ret = dquot_release(dquot); ret = dquot_release(dquot);
@@ -6949,6 +6962,10 @@ static int ext4_release_dquot(struct dquot *dquot)
err = ext4_journal_stop(handle); err = ext4_journal_stop(handle);
if (!ret) if (!ret)
ret = err; ret = err;
if (freeze_protected)
sb_end_intwrite(dquot->dq_sb);
return ret; return ret;
} }