From 661bec6ba884b86517ef5ea529aabb281a7198d9 Mon Sep 17 00:00:00 2001
From: Gabriel de Perthuis <g2p.code@gmail.com>
Date: Wed, 10 Oct 2012 08:50:47 -0600
Subject: [PATCH] Fix a sign bug causing invalid memory access in the ino_paths
 ioctl.

To see the problem, create many hardlinks to the same file (120 should do it),
then look up paths by inode with:

  ls -i
  btrfs inspect inode-resolve -v $ino /mnt/btrfs

I noticed the memory layout of the fspath->val data had some irregularities
(some unnecessary gaps that stop appearing about halfway),
so I'm not sure there aren't any bugs left in it.
---
 fs/btrfs/backref.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index f3187938e081c..2bcbea3f63082 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1186,7 +1186,7 @@ static char *ref_to_path(struct btrfs_root *fs_root,
 	int slot;
 	u64 next_inum;
 	int ret;
-	s64 bytes_left = size - 1;
+	s64 bytes_left = ((s64)size) - 1;
 	struct extent_buffer *eb = eb_in;
 	struct btrfs_key found_key;
 	int leave_spinning = path->leave_spinning;
-- 
2.30.2