ext4: Fix memory and buffer head leak in callers to ext4_ext_find_extent()

The path variable returned via ext4_ext_find_extent is a kmalloc
variable and needs to be freeded.  It also contains a reference to
buffer_head which needs to be dropped.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index e856f66..995ac16 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -349,7 +349,7 @@
 #define ext4_ext_show_leaf(inode,path)
 #endif
 
-static void ext4_ext_drop_refs(struct ext4_ext_path *path)
+void ext4_ext_drop_refs(struct ext4_ext_path *path)
 {
 	int depth = path->p_depth;
 	int i;
@@ -2200,10 +2200,10 @@
 		newdepth = ext_depth(inode);
 		if (newdepth != depth) {
 			depth = newdepth;
-			path = ext4_ext_find_extent(inode, iblock, NULL);
+			ext4_ext_drop_refs(path);
+			path = ext4_ext_find_extent(inode, iblock, path);
 			if (IS_ERR(path)) {
 				err = PTR_ERR(path);
-				path = NULL;
 				goto out;
 			}
 			eh = path[depth].p_hdr;