fix-error-return-from-ext4_ext_handle_uninitialized_extents

   1 ext4: fix error return from ext4_ext_handle_uninitialized_extents()
   2
   3 From: Eric Whitney <enwlinux@gmail.com>
   4
   5 Commit 3779473246 breaks the return of error codes from
   6 ext4_ext_handle_uninitialized_extents() in ext4_ext_map_blocks().  A
   7 portion of the patch assigns that function's signed integer return
   8 value to an unsigned int.  Consequently, negatively valued error codes
   9 are lost and can be treated as a bogus allocated block count.
  10
  11 Signed-off-by: Eric Whitney <enwlinux@gmail.com>
  12 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
  13 Cc: stable@vger.kernel.org
  14 ---
  15  fs/ext4/extents.c | 8 ++++++--
  16  1 file changed, 6 insertions(+), 2 deletions(-)
  17
  18 diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
  19 index 74bc2d5..9875fd0 100644
  20 --- a/fs/ext4/extents.c
  21 +++ b/fs/ext4/extents.c
  22 @@ -4128,7 +4128,7 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
  23         struct ext4_extent newex, *ex, *ex2;
  24         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  25         ext4_fsblk_t newblock = 0;
  26 -       int free_on_err = 0, err = 0, depth;
  27 +       int free_on_err = 0, err = 0, depth, ret;
  28         unsigned int allocated = 0, offset = 0;
  29         unsigned int allocated_clusters = 0;
  30         struct ext4_allocation_request ar;
  31 @@ -4189,9 +4189,13 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
  32                         if (!ext4_ext_is_uninitialized(ex))
  33                                 goto out;
  34
  35 -                       allocated = ext4_ext_handle_uninitialized_extents(
  36 +                       ret = ext4_ext_handle_uninitialized_extents(
  37                                 handle, inode, map, path, flags,
  38                                 allocated, newblock);
  39 +                       if (ret < 0)
  40 +                               err = ret;
  41 +                       else
  42 +                               allocated = ret;
  43                         goto out3;
  44                 }
  45         }
  46 --
  47 1.8.3.2
  48
  49