1 files changed, 8 insertions, 2 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 0381b6007ae4..0f74262911be 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3750,7 +3750,7 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
         }
         if (uptodate)
                 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
-
+again:
         ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
         if (ret)
                 goto free_eb;
@@ -3760,7 +3760,13 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
         if (ret == -EEXIST) {
                 exists = radix_tree_lookup(&tree->buffer,
                                                 start >> PAGE_CACHE_SHIFT);
-                atomic_inc(&exists->refs);
+                if (!atomic_inc_not_zero(&exists->refs)) {
+                        spin_unlock(&tree->buffer_lock);
+                        radix_tree_preload_end();
+                        synchronize_rcu();
+                        exists = NULL;
+                        goto again;
+                }
                 spin_unlock(&tree->buffer_lock);
                 radix_tree_preload_end();
                 goto free_eb;