ext4: fix error handling in ext4_ext_shift_extents

Fix error handling by adding some.  :-)

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 9 insertions, 2 deletions

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 96e0a4bc8faa..38be06354b88 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -5314,11 +5314,18 @@ ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
          * enough to accomodate the shift.
          */
         path = ext4_ext_find_extent(inode, start - 1, NULL, 0);
+        if (IS_ERR(path))
+                return PTR_ERR(path);
         depth = path->p_depth;
         extent =  path[depth].p_ext;
-        ex_start = le32_to_cpu(extent->ee_block);
-        ex_end = le32_to_cpu(extent->ee_block) +
+        if (extent) {
+                ex_start = le32_to_cpu(extent->ee_block);
+                ex_end = le32_to_cpu(extent->ee_block) +
                         ext4_ext_get_actual_len(extent);
+        } else {
+                ex_start = 0;
+                ex_end = 0;
+        }
         ext4_ext_drop_refs(path);
         kfree(path);