2 files changed, 23 insertions, 5 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 30a5094fffa7..db996f0edf0b 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -731,6 +731,7 @@ u32 btrfs_count_snapshots_in_path(struct btrfs_root *root,
         u64 found_owner;
         u64 root_objectid = root->root_key.objectid;
         u32 total_count = 0;
+        u32 extent_refs;
         u32 cur_count;
         u32 nritems;
         int ret;
@@ -767,6 +768,7 @@ again:
         }
 
         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
+        extent_refs = btrfs_extent_refs(l, item);
         while (1) {
                 l = path->nodes[0];
                 nritems = btrfs_header_nritems(l);
@@ -800,10 +802,28 @@ again:
                                 total_count = 2;
                                 goto out;
                         }
+                        /*
+                         * nasty.  we don't count a reference held by
+                         * the running transaction.  This allows nodatacow
+                         * to avoid cow most of the time
+                         */
+                        if (found_owner >= BTRFS_FIRST_FREE_OBJECTID &&
+                            btrfs_ref_generation(l, ref_item) ==
+                            root->fs_info->generation) {
+                                extent_refs--;
+                        }
                 }
                 total_count = 1;
                 path->slots[0]++;
         }
+        /*
+         * if there is more than one reference against a data extent,
+         * we have to assume the other ref is another snapshot
+         */
+        if (level == -1 && extent_refs > 1) {
+                total_count = 2;
+                goto out;
+        }
         if (cur_count == 0) {
                 total_count = 0;
                 goto out;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 1bf37d15b174..a492fd238c88 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -207,9 +207,8 @@ again:
         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
         found_type = btrfs_key_type(&found_key);
         if (found_key.objectid != inode->i_ino ||
-            found_type != BTRFS_EXTENT_DATA_KEY) {
+            found_type != BTRFS_EXTENT_DATA_KEY)
                 goto not_found;
-        }
 
         found_type = btrfs_file_extent_type(leaf, item);
         extent_start = found_key.offset;
@@ -245,7 +244,6 @@ again:
                 if (!block_group || block_group->ro)
                         goto not_found;
 
-
                 start = extent_end;
         } else {
                 goto not_found;
@@ -260,8 +258,8 @@ loop:
         goto again;
 
 not_found:
-        cow_file_range(inode, start, cow_end);
-        start = cow_end + 1;
+        cow_file_range(inode, start, end);
+        start = end + 1;
         goto loop;
 }