1 files changed, 30 insertions, 5 deletions

diff --git a/fs/xfs/xfs_alloc.c b/fs/xfs/xfs_alloc.c
index acdced86413c..95862bbff56b 100644
--- a/fs/xfs/xfs_alloc.c
+++ b/fs/xfs/xfs_alloc.c
@@ -2469,7 +2469,7 @@ xfs_free_extent(
 
         error = xfs_free_ag_extent(tp, args.agbp, args.agno, args.agbno, len, 0);
         if (!error)
-                xfs_alloc_busy_insert(tp, args.agno, args.agbno, len);
+                xfs_alloc_busy_insert(tp, args.agno, args.agbno, len, 0);
 error0:
         xfs_perag_put(args.pag);
         return error;
@@ -2480,7 +2480,8 @@ xfs_alloc_busy_insert(
         struct xfs_trans        *tp,
         xfs_agnumber_t          agno,
         xfs_agblock_t           bno,
-        xfs_extlen_t            len)
+        xfs_extlen_t            len,
+        unsigned int            flags)
 {
         struct xfs_busy_extent  *new;
         struct xfs_busy_extent  *busyp;
@@ -2504,6 +2505,7 @@ xfs_alloc_busy_insert(
         new->bno = bno;
         new->length = len;
         INIT_LIST_HEAD(&new->list);
+        new->flags = flags;
 
         /* trace before insert to be able to see failed inserts */
         trace_xfs_alloc_busy(tp->t_mountp, agno, bno, len);
@@ -2609,6 +2611,18 @@ xfs_alloc_busy_update_extent(
         xfs_agblock_t           bend = bbno + busyp->length;
 
         /*
+         * This extent is currently being discarded.  Give the thread
+         * performing the discard a chance to mark the extent unbusy
+         * and retry.
+         */
+        if (busyp->flags & XFS_ALLOC_BUSY_DISCARDED) {
+                spin_unlock(&pag->pagb_lock);
+                delay(1);
+                spin_lock(&pag->pagb_lock);
+                return false;
+        }
+
+        /*
          * If there is a busy extent overlapping a user allocation, we have
          * no choice but to force the log and retry the search.
          *
@@ -2813,7 +2827,8 @@ restart:
                  * If this is a metadata allocation, try to reuse the busy
                  * extent instead of trimming the allocation.
                  */
-                if (!args->userdata) {
+                if (!args->userdata &&
+                    !(busyp->flags & XFS_ALLOC_BUSY_DISCARDED)) {
                         if (!xfs_alloc_busy_update_extent(args->mp, args->pag,
                                                           busyp, fbno, flen,
                                                           false))
@@ -2979,10 +2994,16 @@ xfs_alloc_busy_clear_one(
         kmem_free(busyp);
 }
 
+/*
+ * Remove all extents on the passed in list from the busy extents tree.
+ * If do_discard is set skip extents that need to be discarded, and mark
+ * these as undergoing a discard operation instead.
+ */
 void
 xfs_alloc_busy_clear(
         struct xfs_mount        *mp,
-        struct list_head        *list)
+        struct list_head        *list,
+        bool                    do_discard)
 {
         struct xfs_busy_extent  *busyp, *n;
         struct xfs_perag        *pag = NULL;
@@ -2999,7 +3020,11 @@ xfs_alloc_busy_clear(
                         agno = busyp->agno;
                 }
 
-                xfs_alloc_busy_clear_one(mp, pag, busyp);
+                if (do_discard && busyp->length &&
+                    !(busyp->flags & XFS_ALLOC_BUSY_SKIP_DISCARD))
+                        busyp->flags = XFS_ALLOC_BUSY_DISCARDED;
+                else
+                        xfs_alloc_busy_clear_one(mp, pag, busyp);
         }
 
         if (pag) {