1 files changed, 21 insertions, 2 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 0ec876657923..251db68148b2 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1271,6 +1271,15 @@ next_slot:
                         disk_bytenr += cur_offset - found_key.offset;
                         num_bytes = min(end + 1, extent_end) - cur_offset;
                         /*
+                         * if there are pending snapshots for this root,
+                         * we fall into common COW way.
+                         */
+                        if (!nolock) {
+                                err = btrfs_start_nocow_write(root);
+                                if (!err)
+                                        goto out_check;
+                        }
+                        /*
                          * force cow if csum exists in the range.
                          * this ensure that csum for a given extent are
                          * either valid or do not exist.
@@ -1289,6 +1298,8 @@ next_slot:
 out_check:
                 if (extent_end <= start) {
                         path->slots[0]++;
+                        if (!nolock && nocow)
+                                btrfs_end_nocow_write(root);
                         goto next_slot;
                 }
                 if (!nocow) {
@@ -1306,8 +1317,11 @@ out_check:
                         ret = cow_file_range(inode, locked_page,
                                              cow_start, found_key.offset - 1,
                                              page_started, nr_written, 1);
-                        if (ret)
+                        if (ret) {
+                                if (!nolock && nocow)
+                                        btrfs_end_nocow_write(root);
                                 goto error;
+                        }
                         cow_start = (u64)-1;
                 }
 
@@ -1354,8 +1368,11 @@ out_check:
                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
                                                       num_bytes);
-                        if (ret)
+                        if (ret) {
+                                if (!nolock && nocow)
+                                        btrfs_end_nocow_write(root);
                                 goto error;
+                        }
                 }
 
                 extent_clear_unlock_delalloc(inode, cur_offset,
@@ -1363,6 +1380,8 @@ out_check:
                                              locked_page, EXTENT_LOCKED |
                                              EXTENT_DELALLOC, PAGE_UNLOCK |
                                              PAGE_SET_PRIVATE2);
+                if (!nolock && nocow)
+                        btrfs_end_nocow_write(root);
                 cur_offset = extent_end;
                 if (cur_offset > end)
                         break;