ocfs2: Protect periodic quota syncing with s_umount semaphore

New quota locking rules will require s_umount semaphore for all quota
scanning functions. Add is for periodic quota syncing.

Tested-by: Eric Ren <zren@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/ocfs2/quota_global.c b/fs/ocfs2/quota_global.c
index 87e577a..cec495a 100644 (file)
--- a/fs/ocfs2/quota_global.c
+++ b/fs/ocfs2/quota_global.c
@@ -634,7 +634,15 @@ static void qsync_work_fn(struct work_struct *work)
                                                      dqi_sync_work.work);
        struct super_block *sb = oinfo->dqi_gqinode->i_sb;
 
-       dquot_scan_active(sb, ocfs2_sync_dquot_helper, oinfo->dqi_type);
+       /*
+        * We have to be careful here not to deadlock on s_umount as umount
+        * disabling quotas may be in progress and it waits for this work to
+        * complete. If trylock fails, we'll do the sync next time...
+        */
+       if (down_read_trylock(&sb->s_umount)) {
+               dquot_scan_active(sb, ocfs2_sync_dquot_helper, oinfo->dqi_type);
+               up_read(&sb->s_umount);
+       }
        schedule_delayed_work(&oinfo->dqi_sync_work,
                              msecs_to_jiffies(oinfo->dqi_syncms));
 }

diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index f56fe39..5b9c0df 100644 (file)
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -985,7 +985,6 @@ static void ocfs2_disable_quotas(struct ocfs2_super *osb)
        for (type = 0; type < OCFS2_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]);