mount: Add ->collect callback

This helps cleanup cr-time mounts a little bit.

travis-ci: success for mount: Add ->collect callback
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

criu/filesystems.c

@@ -39,7 +39,7 @@ struct binfmt_misc_info {
 
 LIST_HEAD(binfmt_misc_list);
 
-static int binfmt_misc_parse(struct mount_info *pm)
+static int binfmt_misc_parse_or_collect(struct mount_info *pm)
 {
 	opts.has_binfmt_misc = true;
 	return 0;
@@ -375,7 +375,7 @@ int collect_binfmt_misc(void)
 #else
 #define binfmt_misc_dump	NULL
 #define binfmt_misc_restore	NULL
-#define binfmt_misc_parse	NULL
+#define binfmt_misc_parse_or_collect NULL
 #endif
 
 static int tmpfs_dump(struct mount_info *pm)
@@ -684,7 +684,8 @@ static struct fstype fstypes[] = {
 		.restore = devtmpfs_restore,
 	}, {
 		.name = "binfmt_misc",
-		.parse = binfmt_misc_parse,
+		.parse = binfmt_misc_parse_or_collect,
+		.collect = binfmt_misc_parse_or_collect,
 		.code = FSTYPE__BINFMT_MISC,
 		.dump = binfmt_misc_dump,
 		.restore = binfmt_misc_restore,

criu/include/filesystems.h

@@ -14,6 +14,7 @@ struct fstype {
 	int (*dump)(struct mount_info *pm);
 	int (*restore)(struct mount_info *pm);
 	int (*parse)(struct mount_info *pm);
+	int (*collect)(struct mount_info *pm);
 	bool (*sb_equal)(struct mount_info *a, struct mount_info *b);
 	mount_fn_t mount;
 };

criu/mount.c

@@ -2580,13 +2580,11 @@ static int collect_mnt_from_image(struct mount_info **pms, struct ns_id *nsid)
 			goto err;
 		}
 
-#ifdef CONFIG_BINFMT_MISC_VIRTUALIZED
-		if (me->fstype == FSTYPE__BINFMT_MISC)
-			opts.has_binfmt_misc = true;
-#endif
-
 		/* FIXME: abort unsupported early */
 		pm->fstype = decode_fstype(me->fstype);
+		if (pm->fstype->collect && (pm->fstype->collect(pm) < 0))
+			goto err;
+
 
 		if (me->fsname) {
 			pm->fsname = xstrdup(me->fsname);