1 files changed, 22 insertions, 12 deletions

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 696bf695d8eb..1ce5dd154499 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -597,29 +597,37 @@ fail:
  * Each bit represents a sector. Thus caller should ensure @csum_buf passed
  * in is large enough to contain all csums.
  */
-int btrfs_lookup_csums_bitmap(struct btrfs_root *root, u64 start, u64 end,
-			      u8 *csum_buf, unsigned long *csum_bitmap,
-			      bool search_commit)
+int btrfs_lookup_csums_bitmap(struct btrfs_root *root, struct btrfs_path *path,
+			      u64 start, u64 end, u8 *csum_buf,
+			      unsigned long *csum_bitmap)
 {
 	struct btrfs_fs_info *fs_info = root->fs_info;
 	struct btrfs_key key;
-	struct btrfs_path *path;
 	struct extent_buffer *leaf;
 	struct btrfs_csum_item *item;
 	const u64 orig_start = start;
+	bool free_path = false;
 	int ret;
 
 	ASSERT(IS_ALIGNED(start, fs_info->sectorsize) &&
 	       IS_ALIGNED(end + 1, fs_info->sectorsize));
 
-	path = btrfs_alloc_path();
-	if (!path)
-		return -ENOMEM;
+	if (!path) {
+		path = btrfs_alloc_path();
+		if (!path)
+			return -ENOMEM;
+		free_path = true;
+	}
 
-	if (search_commit) {
-		path->skip_locking = 1;
-		path->reada = READA_FORWARD;
-		path->search_commit_root = 1;
+	/* Check if we can reuse the previous path. */
+	if (path->nodes[0]) {
+		btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
+
+		if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
+		    key.type == BTRFS_EXTENT_CSUM_KEY &&
+		    key.offset <= start)
+			goto search_forward;
+		btrfs_release_path(path);
 	}
 
 	key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
@@ -656,6 +664,7 @@ int btrfs_lookup_csums_bitmap(struct btrfs_root *root, u64 start, u64 end,
 		}
 	}
 
+search_forward:
 	while (start <= end) {
 		u64 csum_end;
 
@@ -712,7 +721,8 @@ int btrfs_lookup_csums_bitmap(struct btrfs_root *root, u64 start, u64 end,
 	}
 	ret = 0;
 fail:
-	btrfs_free_path(path);
+	if (free_path)
+		btrfs_free_path(path);
 	return ret;
 }