diff options
| author | Dmitry Monakhov <dmtrmonakhov@yandex-team.ru> | 2019-10-31 13:39:20 +0300 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2020-02-11 23:03:23 +0300 |
| commit | 9c64da63c028a800020bc9f7e139b8ba2d8f11ed (patch) | |
| tree | bd17b5fb4a508c12f348fcb7306a8808603658dc /fs/ocfs2 | |
| parent | 7f8f231ca569b39265277c86297569634da2891d (diff) | |
| download | linux-9c64da63c028a800020bc9f7e139b8ba2d8f11ed.tar.xz | |
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
Signed-off-by: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'fs/ocfs2')
| -rw-r--r-- | fs/ocfs2/quota_global.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ocfs2/quota_global.c b/fs/ocfs2/quota_global.c index b990a62cff50..5524b5bad5ba 100644 --- a/fs/ocfs2/quota_global.c +++ b/fs/ocfs2/quota_global.c @@ -714,7 +714,7 @@ static int ocfs2_release_dquot(struct dquot *dquot) mutex_lock(&dquot->dq_lock); /* Check whether we are not racing with some other dqget() */ - if (atomic_read(&dquot->dq_count) > 1) + if (dquot_is_busy(dquot)) goto out; /* Running from downconvert thread? Postpone quota processing to wq */ if (current == osb->dc_task) { |