ocfs2: Fix lock inversion in quotas during umount

We cannot cancel delayed work from ocfs2_local_free_info because that is called
with dqonoff_mutex held and the work it cancels requires dqonoff_mutex to
finish. Cancel the work before acquiring dqonoff_mutex.

Acked-by: Joel Becker <Joel.Becker@oracle.com>
Signed-off-by: Jan Kara <jack@suse.cz>

2 files changed, 4 insertions, 4 deletions

diff --git a/fs/ocfs2/quota_local.c b/fs/ocfs2/quota_local.c
index 551a6bff9f2c..8bd70d4d184d 100644
--- a/fs/ocfs2/quota_local.c
+++ b/fs/ocfs2/quota_local.c
@@ -816,10 +816,6 @@ static int ocfs2_local_free_info(struct super_block *sb, int type)
         int mark_clean = 1, len;
         int status;
 
-        /* At this point we know there are no more dquots and thus
-         * even if there's some sync in the pdflush queue, it won't
-         * find any dquots and return without doing anything */
-        cancel_delayed_work_sync(&oinfo->dqi_sync_work);
         iput(oinfo->dqi_gqinode);
         ocfs2_simple_drop_lockres(OCFS2_SB(sb), &oinfo->dqi_gqlock);
         ocfs2_lock_res_free(&oinfo->dqi_gqlock);
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 1c2c39f6f0b6..2c26ce251cb3 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -938,12 +938,16 @@ static void ocfs2_disable_quotas(struct ocfs2_super *osb)
         int type;
         struct inode *inode;
         struct super_block *sb = osb->sb;
+        struct ocfs2_mem_dqinfo *oinfo;
 
         /* We mostly ignore errors in this function because there's not much
          * we can do when we see them */
         for (type = 0; type < MAXQUOTAS; type++) {
                 if (!sb_has_quota_loaded(sb, type))
                         continue;
+                /* Cancel periodic syncing before we grab dqonoff_mutex */
+                oinfo = sb_dqinfo(sb, type)->dqi_priv;
+                cancel_delayed_work_sync(&oinfo->dqi_sync_work);
                 inode = igrab(sb->s_dquot.files[type]);
                 /* Turn off quotas. This will remove all dquot structures from
                  * memory and so they will be automatically synced to global