1 files changed, 19 insertions, 3 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 18ea90c8943b..0b044e509e9f 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4063,23 +4063,30 @@ int btrfs_snap_reserve_metadata(struct btrfs_trans_handle *trans,
  */
 static unsigned drop_outstanding_extent(struct inode *inode)
 {
+        unsigned drop_inode_space = 0;
         unsigned dropped_extents = 0;
 
         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
         BTRFS_I(inode)->outstanding_extents--;
 
+        if (BTRFS_I(inode)->outstanding_extents == 0 &&
+            BTRFS_I(inode)->delalloc_meta_reserved) {
+                drop_inode_space = 1;
+                BTRFS_I(inode)->delalloc_meta_reserved = 0;
+        }
+
         /*
          * If we have more or the same amount of outsanding extents than we have
          * reserved then we need to leave the reserved extents count alone.
          */
         if (BTRFS_I(inode)->outstanding_extents >=
             BTRFS_I(inode)->reserved_extents)
-                return 0;
+                return drop_inode_space;
 
         dropped_extents = BTRFS_I(inode)->reserved_extents -
                 BTRFS_I(inode)->outstanding_extents;
         BTRFS_I(inode)->reserved_extents -= dropped_extents;
-        return dropped_extents;
+        return dropped_extents + drop_inode_space;
 }
 
 /**
@@ -4165,9 +4172,18 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
                 nr_extents = BTRFS_I(inode)->outstanding_extents -
                         BTRFS_I(inode)->reserved_extents;
                 BTRFS_I(inode)->reserved_extents += nr_extents;
+        }
 
-                to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
+        /*
+         * Add an item to reserve for updating the inode when we complete the
+         * delalloc io.
+         */
+        if (!BTRFS_I(inode)->delalloc_meta_reserved) {
+                nr_extents++;
+                BTRFS_I(inode)->delalloc_meta_reserved = 1;
         }
+
+        to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
         spin_unlock(&BTRFS_I(inode)->lock);