f2fs: avoid null dereference in f2fs_acl_from_disk

This patch resolves Coverity #751303:

>>> CID 753103: Explicit null dereferenced (FORWARD_NULL) Passing null
>>> pointer "value" to function "f2fs_acl_from_disk(char const *, size_t)",
	which dereferences it.

[Error path]
- value = NULL;
- retval = 0 by f2fs_getxattr();
- f2fs_acl_from_disk(value:NULL, ...);

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

1 files changed, 6 insertions, 7 deletions

diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c
index e95b94945d5f..137af4255da6 100644
--- a/fs/f2fs/acl.c
+++ b/fs/f2fs/acl.c
@@ -191,15 +191,14 @@ struct posix_acl *f2fs_get_acl(struct inode *inode, int type)
                 retval = f2fs_getxattr(inode, name_index, "", value, retval);
         }
 
-        if (retval < 0) {
-                if (retval == -ENODATA)
-                        acl = NULL;
-                else
-                        acl = ERR_PTR(retval);
-        } else {
+        if (retval > 0)
                 acl = f2fs_acl_from_disk(value, retval);
-        }
+        else if (retval == -ENODATA)
+                acl = NULL;
+        else
+                acl = ERR_PTR(retval);
         kfree(value);
+
         if (!IS_ERR(acl))
                 set_cached_acl(inode, type, acl);