ext4: fix memory leakage in mext_check_coverage

Regression was introduced by following commit 8c854473
TESTCASE (git://oss.sgi.com/xfs/cmds/xfstests.git):
#while true;do ./check 301 || break ;done

Also fix potential memory leakage in get_ext_path() once
ext4_ext_find_extent() have failed.

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

1 files changed, 19 insertions, 16 deletions

diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index c1f15b203e98..bbae4ed15c3d 100644
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -32,16 +32,18 @@
  */
 static inline int
 get_ext_path(struct inode *inode, ext4_lblk_t lblock,
-                struct ext4_ext_path **path)
+                struct ext4_ext_path **orig_path)
 {
         int ret = 0;
+        struct ext4_ext_path *path;
 
-        *path = ext4_ext_find_extent(inode, lblock, *path);
-        if (IS_ERR(*path)) {
-                ret = PTR_ERR(*path);
-                *path = NULL;
-        } else if ((*path)[ext_depth(inode)].p_ext == NULL)
+        path = ext4_ext_find_extent(inode, lblock, *orig_path);
+        if (IS_ERR(path))
+                ret = PTR_ERR(path);
+        else if (path[ext_depth(inode)].p_ext == NULL)
                 ret = -ENODATA;
+        else
+                *orig_path = path;
 
         return ret;
 }
@@ -611,24 +613,25 @@ mext_check_coverage(struct inode *inode, ext4_lblk_t from, ext4_lblk_t count,
 {
         struct ext4_ext_path *path = NULL;
         struct ext4_extent *ext;
+        int ret = 0;
         ext4_lblk_t last = from + count;
         while (from < last) {
                 *err = get_ext_path(inode, from, &path);
                 if (*err)
-                        return 0;
+                        goto out;
                 ext = path[ext_depth(inode)].p_ext;
-                if (!ext) {
-                        ext4_ext_drop_refs(path);
-                        return 0;
-                }
-                if (uninit != ext4_ext_is_uninitialized(ext)) {
-                        ext4_ext_drop_refs(path);
-                        return 0;
-                }
+                if (uninit != ext4_ext_is_uninitialized(ext))
+                        goto out;
                 from += ext4_ext_get_actual_len(ext);
                 ext4_ext_drop_refs(path);
         }
-        return 1;
+        ret = 1;
+out:
+        if (path) {
+                ext4_ext_drop_refs(path);
+                kfree(path);
+        }
+        return ret;
 }
 
 /**