diff options
| author | Dmitry Monakhov <dmtrmonakhov@yandex-team.ru> | 2019-10-31 10:39:20 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-12-17 20:39:43 +0100 |
| commit | f780a35182bf0c37668f734d2bbf8e5dd63d8713 (patch) | |
| tree | 0722de9b84231465e0c32f94cf27bfd606cb017c /include | |
| parent | 772098e8b6999656b9b28d78f52f80b224556c06 (diff) | |
quota: Check that quota is not dirty before release
commit df4bb5d128e2c44848aeb36b7ceceba3ac85080d upstream.
There is a race window where quota was redirted once we drop dq_list_lock inside dqput(),
but before we grab dquot->dq_lock inside dquot_release()
TASK1 TASK2 (chowner)
->dqput()
we_slept:
spin_lock(&dq_list_lock)
if (dquot_dirty(dquot)) {
spin_unlock(&dq_list_lock);
dquot->dq_sb->dq_op->write_dquot(dquot);
goto we_slept
if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
spin_unlock(&dq_list_lock);
dquot->dq_sb->dq_op->release_dquot(dquot);
dqget()
mark_dquot_dirty()
dqput()
goto we_slept;
}
So dquot dirty quota will be released by TASK1, but on next we_sleept loop
we detect this and call ->write_dquot() for it.
XFSTEST: https://github.com/dmonakhov/xfstests/commit/440a80d4cbb39e9234df4d7240aee1d551c36107
Link: https://lore.kernel.org/r/20191031103920.3919-2-dmonakhov@openvz.org
CC: stable@vger.kernel.org
Signed-off-by: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/quotaops.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h index a109e6107c06..50ab5d6ccc4e 100644 --- a/include/linux/quotaops.h +++ b/include/linux/quotaops.h @@ -51,6 +51,16 @@ static inline struct dquot *dqgrab(struct dquot *dquot) atomic_inc(&dquot->dq_count); return dquot; } + +static inline bool dquot_is_busy(struct dquot *dquot) +{ + if (test_bit(DQ_MOD_B, &dquot->dq_flags)) + return true; + if (atomic_read(&dquot->dq_count) > 1) + return true; + return false; +} + void dqput(struct dquot *dquot); int dquot_scan_active(struct super_block *sb, int (*fn)(struct dquot *dquot, unsigned long priv), |