xfs: add missing bmap cancel calls in error paths

If a failure occurs after the bmap free list is populated and before
xfs_bmap_finish() completes successfully (which returns a partial
list on failure), the bmap free list must be cancelled. Otherwise,
the extent items on the list are never freed and a memory leak
occurs.

Several random error paths throughout the code suffer this problem.
Fix these up such that xfs_bmap_cancel() is always called on error.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 3da9f4d..cee2f69 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1791,14 +1791,15 @@
 	xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_ICOUNT, -1);
 
 	/*
-	 * Just ignore errors at this point.  There is nothing we can
-	 * do except to try to keep going. Make sure it's not a silent
-	 * error.
+	 * Just ignore errors at this point.  There is nothing we can do except
+	 * to try to keep going. Make sure it's not a silent error.
 	 */
 	error = xfs_bmap_finish(&tp,  &free_list, &committed);
-	if (error)
+	if (error) {
 		xfs_notice(mp, "%s: xfs_bmap_finish returned error %d",
 			__func__, error);
+		xfs_bmap_cancel(&free_list);
+	}
 	error = xfs_trans_commit(tp);
 	if (error)
 		xfs_notice(mp, "%s: xfs_trans_commit returned error %d",