Btrfs: Fix .. lookup corner case

Inode ref item can be in the next leaf when we find "path->slots[0] ==
btrfs_header_nritems(...)".

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

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 8bc981c4f5efd0b5cca955756494559d81f2636b..cf9534b79aba13774a975f27d2e519d5f692f568 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1752,21 +1752,18 @@ static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
        if (namelen == 2 && strcmp(name, "..") == 0) {
                struct btrfs_key key;
                struct extent_buffer *leaf;
-               u32 nritems;
                int slot;
 
                key.objectid = dir->i_ino;
+               key.offset = (u64)-1;
                btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
-               key.offset = 0;
+               if (ret < 0 || path->slots[0] == 0)
+                       goto out_err;
                ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
                BUG_ON(ret == 0);
                ret = 0;
-
                leaf = path->nodes[0];
-               slot = path->slots[0];
-               nritems = btrfs_header_nritems(leaf);
-               if (slot >= nritems)
-                       goto out_err;
+               slot = path->slots[0] - 1;
 
                btrfs_item_key_to_cpu(leaf, &key, slot);
                if (key.objectid != dir->i_ino ||
@@ -1980,16 +1977,15 @@ static int btrfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
        /* special case for .., just use the back ref */
        if (filp->f_pos == 1) {
                btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
-               key.offset = 0;
+               key.offset = (u64)-1;
                ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
-               BUG_ON(ret == 0);
-               leaf = path->nodes[0];
-               slot = path->slots[0];
-               nritems = btrfs_header_nritems(leaf);
-               if (slot >= nritems) {
+               if (ret < 0 || path->slots[0] == 0) {
                        btrfs_release_path(root, path);
                        goto read_dir_items;
                }
+               BUG_ON(ret == 0);
+               leaf = path->nodes[0];
+               slot = path->slots[0] - 1;
                btrfs_item_key_to_cpu(leaf, &found_key, slot);
                btrfs_release_path(root, path);
                if (found_key.objectid != key.objectid ||