1 files changed, 26 insertions, 12 deletions

diff --git a/fs/xfs/quota/xfs_dquot.c b/fs/xfs/quota/xfs_dquot.c
index 591ca6602bfb..6543c0b29753 100644
--- a/fs/xfs/quota/xfs_dquot.c
+++ b/fs/xfs/quota/xfs_dquot.c
@@ -73,6 +73,8 @@ int xfs_dqreq_num;
 int xfs_dqerror_mod = 33;
 #endif
 
+static struct lock_class_key xfs_dquot_other_class;
+
 /*
  * Allocate and initialize a dquot. We don't always allocate fresh memory;
  * we try to reclaim a free dquot if the number of incore dquots are above
@@ -139,7 +141,15 @@ xfs_qm_dqinit(
                  ASSERT(dqp->q_trace);
                  xfs_dqtrace_entry(dqp, "DQRECLAIMED_INIT");
 #endif
-         }
+        }
+
+        /*
+         * In either case we need to make sure group quotas have a different
+         * lock class than user quotas, to make sure lockdep knows we can
+         * locks of one of each at the same time.
+         */
+        if (!(type & XFS_DQ_USER))
+                lockdep_set_class(&dqp->q_qlock, &xfs_dquot_other_class);
 
         /*
          * log item gets initialized later
@@ -421,7 +431,7 @@ xfs_qm_dqalloc(
         /*
          * Initialize the bmap freelist prior to calling bmapi code.
          */
-        XFS_BMAP_INIT(&flist, &firstblock);
+        xfs_bmap_init(&flist, &firstblock);
         xfs_ilock(quotip, XFS_ILOCK_EXCL);
         /*
          * Return if this type of quotas is turned off while we didn't
@@ -1383,6 +1393,12 @@ xfs_dqunlock_nonotify(
         mutex_unlock(&(dqp->q_qlock));
 }
 
+/*
+ * Lock two xfs_dquot structures.
+ *
+ * To avoid deadlocks we always lock the quota structure with
+ * the lowerd id first.
+ */
 void
 xfs_dqlock2(
         xfs_dquot_t     *d1,
@@ -1392,18 +1408,16 @@ xfs_dqlock2(
                 ASSERT(d1 != d2);
                 if (be32_to_cpu(d1->q_core.d_id) >
                     be32_to_cpu(d2->q_core.d_id)) {
-                        xfs_dqlock(d2);
-                        xfs_dqlock(d1);
+                        mutex_lock(&d2->q_qlock);
+                        mutex_lock_nested(&d1->q_qlock, XFS_QLOCK_NESTED);
                 } else {
-                        xfs_dqlock(d1);
-                        xfs_dqlock(d2);
-                }
-        } else {
-                if (d1) {
-                        xfs_dqlock(d1);
-                } else if (d2) {
-                        xfs_dqlock(d2);
+                        mutex_lock(&d1->q_qlock);
+                        mutex_lock_nested(&d2->q_qlock, XFS_QLOCK_NESTED);
                 }
+        } else if (d1) {
+                mutex_lock(&d1->q_qlock);
+        } else if (d2) {
+                mutex_lock(&d2->q_qlock);
         }
 }