btrfs-progs: btrfs-convert.c : check source file system state

index c10dc17..27da9ce 100644
@@ -2171,6 +2171,17 @@ static void ext2_copy_inode_item(struct btrfs_inode_item *dst,
 	}
 	memset(&dst->reserved, 0, sizeof(dst->reserved));
 }
+static int check_filesystem_state(struct btrfs_convert_context *cctx)
+{
+	ext2_filsys fs = cctx->fs_data;
+
+        if (!(fs->super->s_state & EXT2_VALID_FS))
+		return 1;
+	else if (fs->super->s_state & EXT2_ERROR_FS)
+		return 1;
+	else
+		return 0;
+}
 
 /*
  * copy a single inode. do all the required works, such as cloning

@@ -2340,6 +2351,10 @@ static int do_convert(const char *devname, int datacsum, int packing,
 	ret = convert_open_fs(devname, &cctx);
 	if (ret)
 		goto fail;
+	ret = check_filesystem_state(&cctx);
+	if (ret) 
+		warning("Source Filesystem is not clean, \
+			 running e2fsck is recommended.");
 	ret = convert_read_used_space(&cctx);
 	if (ret)
 		goto fail;