ext4: fix error return from ext4_ext_handle_uninitialized_extents()

commit ce37c42919608e96ade3748fe23c3062a0a966c5 upstream.

Commit 3779473246 breaks the return of error codes from
ext4_ext_handle_uninitialized_extents() in ext4_ext_map_blocks().  A
portion of the patch assigns that function's signed integer return
value to an unsigned int.  Consequently, negatively valued error codes
are lost and can be treated as a bogus allocated block count.

Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 6 insertions, 2 deletions

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index a2b625e279db..141d0fce318d 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4032,7 +4032,7 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
         struct ext4_extent newex, *ex, *ex2;
         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
         ext4_fsblk_t newblock = 0;
-        int free_on_err = 0, err = 0, depth;
+        int free_on_err = 0, err = 0, depth, ret;
         unsigned int allocated = 0, offset = 0;
         unsigned int allocated_clusters = 0;
         struct ext4_allocation_request ar;
@@ -4093,9 +4093,13 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
                         if (!ext4_ext_is_uninitialized(ex))
                                 goto out;
 
-                        allocated = ext4_ext_handle_uninitialized_extents(
+                        ret = ext4_ext_handle_uninitialized_extents(
                                 handle, inode, map, path, flags,
                                 allocated, newblock);
+                        if (ret < 0)
+                                err = ret;
+                        else
+                                allocated = ret;
                         goto out3;
                 }
         }