Btrfs: Add readahead to the online shrinker, and a mount -o alloc_start= for testing

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 2b3ffa707eae..8fa92a2d9819 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -2654,9 +2654,9 @@ int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
  */
 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
 {
+        u64 bytenr;
         int slot;
         int level = 1;
-        u64 bytenr;
         struct extent_buffer *c;
         struct extent_buffer *next = NULL;
 
@@ -2687,11 +2687,14 @@ int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
                 level--;
                 c = path->nodes[level];
                 free_extent_buffer(c);
+                slot = btrfs_header_nritems(next);
+                if (slot != 0)
+                        slot--;
                 path->nodes[level] = next;
-                path->slots[level] = 0;
+                path->slots[level] = slot;
                 if (!level)
                         break;
-                next = read_tree_block(root, btrfs_node_blockptr(next, 0),
+                next = read_tree_block(root, btrfs_node_blockptr(next, slot),
                                        btrfs_level_size(root, level - 1));
         }
         return 0;