From 068132bad1de70f85f5f6d12c36d64f8f7848d92 Mon Sep 17 00:00:00 2001
From: Daniel J Blueman <daniel.blueman@gmail.com>
Date: Thu, 23 Jun 2011 23:01:01 +0800
Subject: [PATCH] btrfs: fix oops on failure path
If lookup_extent_backref fails, path->nodes[0] reasonably could be
null along with other callers of btrfs_print_leaf, so ensure we have a
valid extent buffer before dereferencing.
Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com>
---
fs/btrfs/print-tree.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/print-tree.c b/fs/btrfs/print-tree.c
index fb2605d998e9..f38e452486b8 100644
--- a/fs/btrfs/print-tree.c
+++ b/fs/btrfs/print-tree.c
@@ -158,8 +158,7 @@ static void print_extent_ref_v0(struct extent_buffer *eb, int slot)
void btrfs_print_leaf(struct btrfs_root *root, struct extent_buffer *l)
{
int i;
- u32 type;
- u32 nr = btrfs_header_nritems(l);
+ u32 type, nr;
struct btrfs_item *item;
struct btrfs_root_item *ri;
struct btrfs_dir_item *di;
@@ -172,6 +171,11 @@ void btrfs_print_leaf(struct btrfs_root *root, struct extent_buffer *l)
struct btrfs_key key;
struct btrfs_key found_key;
+ if (!l)
+ return;
+
+ nr = btrfs_header_nritems(l);
+
printk(KERN_INFO "leaf %llu total ptrs %d free space %d\n",
(unsigned long long)btrfs_header_bytenr(l), nr,
btrfs_leaf_free_space(root, l));
--
2.30.2