David Sterba
2014-Jul-23 20:56 UTC
[PATCH] btrfs-progs: wait until all subvolumes are cleaned
Enhance the 'subvolume' subcommand to wait until a given list of
subvolumes or all currently scheduled for deletion are cleaned
completely from the filesystem.
Signed-off-by: David Sterba <dsterba@suse.cz>
---
'wait' seemed too generic, 'sync' is not completely accurate but
IMHO better,
I'm open to other suggestions
cmds-subvolume.c | 231 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 231 insertions(+)
diff --git a/cmds-subvolume.c b/cmds-subvolume.c
index 5e821c712e74..07485acbc1bd 100644
--- a/cmds-subvolume.c
+++ b/cmds-subvolume.c
@@ -1035,6 +1035,236 @@ out:
return !!ret;
}
+static const char * const cmd_subvol_sync_usage[] = {
+ "btrfs subvolume sync <path> [<subvol-id>...]",
+ "Wait until given subvolume(s) are completely cleaned",
+ "Wait until given subvolume(s) are completely cleaned after
deletion.",
+ "If no subvolume id is given, wait until there are no more
snapshots",
+ "to be cleaned. This may take long if new deleted subvolumes
appear",
+ "during the sleep interval.",
+ "",
+ "-s <N> sleep N seconds between checks (default: 1)",
+ NULL
+};
+
+static int is_subvolume_cleaned(int fd, u64 subvolid)
+{
+ int ret;
+ struct btrfs_ioctl_search_args args;
+ struct btrfs_ioctl_search_key *sk = &args.key;
+
+ sk->tree_id = BTRFS_ROOT_TREE_OBJECTID;
+ sk->min_objectid = subvolid;
+ sk->max_objectid = subvolid;
+ sk->min_type = BTRFS_ROOT_ITEM_KEY;
+ sk->max_type = BTRFS_ROOT_ITEM_KEY;
+ sk->min_offset = 0;
+ sk->max_offset = (u64)-1;
+ sk->min_transid = 0;
+ sk->max_transid = (u64)-1;
+ sk->nr_items = 1;
+
+ ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args);
+ if (ret < 0)
+ return -errno;
+
+ if (sk->nr_items == 0)
+ return 1;
+
+ return 0;
+}
+
+/*
+ * If we're looking for any dead subvolume, take a shortcut and look
+ * for any ORPHAN_ITEMs in the tree root
+ */
+static int fs_has_dead_subvolumes(int fd)
+{
+ int ret;
+ struct btrfs_ioctl_search_args args;
+ struct btrfs_ioctl_search_key *sk = &args.key;
+ struct btrfs_ioctl_search_header sh;
+ u64 min_subvolid = 0;
+
+again:
+ sk->tree_id = BTRFS_ROOT_TREE_OBJECTID;
+ sk->min_objectid = BTRFS_ORPHAN_OBJECTID;
+ sk->max_objectid = BTRFS_ORPHAN_OBJECTID;
+ sk->min_type = BTRFS_ORPHAN_ITEM_KEY;
+ sk->max_type = BTRFS_ORPHAN_ITEM_KEY;
+ sk->min_offset = min_subvolid;
+ sk->max_offset = (u64)-1;
+ sk->min_transid = 0;
+ sk->max_transid = (u64)-1;
+ sk->nr_items = 1;
+
+ ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args);
+ if (ret < 0)
+ return -errno;
+
+ if (!sk->nr_items)
+ return 0;
+
+ memcpy(&sh, args.buf, sizeof(sh));
+ min_subvolid = sh.offset;
+
+ /*
+ * Verify that the root item is really there and we haven't hit
+ * a stale orphan
+ */
+ sk->tree_id = BTRFS_ROOT_TREE_OBJECTID;
+ sk->min_objectid = min_subvolid;
+ sk->max_objectid = min_subvolid;
+ sk->min_type = BTRFS_ROOT_ITEM_KEY;
+ sk->max_type = BTRFS_ROOT_ITEM_KEY;
+ sk->min_offset = 0;
+ sk->max_offset = (u64)-1;
+ sk->min_transid = 0;
+ sk->max_transid = (u64)-1;
+ sk->nr_items = 1;
+
+ ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args);
+ if (ret < 0)
+ return -errno;
+
+ /*
+ * Stale orphan, try the next one
+ */
+ if (!sk->nr_items) {
+ min_subvolid++;
+ goto again;
+ }
+
+ return 1;
+}
+
+static int cmd_subvol_sync(int argc, char **argv)
+{
+ int fd = -1;
+ int i;
+ int ret = 1;
+ DIR *dirstream = NULL;
+ u64 *ids = NULL;
+ int id_count;
+ int remaining;
+ int sleep_interval = 1;
+
+ optind = 1;
+ while (1) {
+ int c = getopt(argc, argv, "s:");
+
+ if (c < 0)
+ break;
+
+ switch (c) {
+ case 's':
+ sleep_interval = atoi(argv[optind]);
+ if (sleep_interval < 1) {
+ fprintf(stderr,
+ "ERROR: invalid sleep interval %s\n",
+ argv[optind]);
+ ret = 1;
+ goto out;
+ }
+ break;
+ default:
+ usage(cmd_subvol_sync_usage);
+ }
+ }
+
+ if (check_argc_min(argc - optind, 1))
+ usage(cmd_subvol_sync_usage);
+
+ fd = open_file_or_dir(argv[optind], &dirstream);
+ if (fd < 0) {
+ fprintf(stderr, "ERROR: can't access '%s'\n",
argv[optind]);
+ ret = 1;
+ goto out;
+ }
+ optind++;
+
+ id_count = argc - optind;
+
+ /*
+ * Wait for all
+ */
+ if (!id_count) {
+ while (1) {
+ ret = fs_has_dead_subvolumes(fd);
+ if (ret < 0) {
+ fprintf(stderr, "ERROR: can't perform the search - %s\n",
+ strerror(-ret));
+ ret = 1;
+ goto out;
+ }
+ if (!ret)
+ goto out;
+ sleep(sleep_interval);
+ }
+ }
+
+ /*
+ * Wait only for the requested ones
+ */
+ ids = (u64*)malloc(sizeof(u64) * id_count);
+
+ if (!ids) {
+ fprintf(stderr, "ERROR: not enough memory\n");
+ ret = 1;
+ goto out;
+ }
+
+ for (i = 0; i < id_count; i++) {
+ u64 id;
+ const char *arg;
+
+ arg = argv[optind + i];
+ errno = 0;
+ id = strtoull(arg, NULL, 10);
+ if (errno < 0) {
+ fprintf(stderr, "ERROR: unrecognized subovlume id %s\n",
+ arg);
+ ret = 1;
+ goto out;
+ }
+ if (id < BTRFS_FIRST_FREE_OBJECTID || id > BTRFS_LAST_FREE_OBJECTID) {
+ fprintf(stderr, "ERROR: subovlume id %s out of range\n",
+ arg);
+ ret = 1;
+ goto out;
+ }
+ ids[i] = id;
+ }
+
+ remaining = id_count;
+ while (1) {
+ for (i = 0; i < id_count; i++) {
+ if (!ids[i])
+ continue;
+ ret = is_subvolume_cleaned(fd, ids[i]);
+ if (ret < 0) {
+ fprintf(stderr, "ERROR: can't perform the search - %s\n",
+ strerror(-ret));
+ goto out;
+ }
+ if (ret) {
+ printf("Subvolume id %llu is gone\n", ids[i]);
+ ids[i] = 0;
+ remaining--;
+ }
+ }
+ if (!remaining)
+ break;
+ sleep(sleep_interval);
+ }
+
+out:
+ free(ids);
+ close_file_or_dir(fd, dirstream);
+
+ return !!ret;
+}
+
const struct cmd_group subvolume_cmd_group = {
subvolume_cmd_group_usage, NULL, {
{ "create", cmd_subvol_create, cmd_subvol_create_usage, NULL, 0 },
@@ -1047,6 +1277,7 @@ const struct cmd_group subvolume_cmd_group = {
cmd_subvol_set_default_usage, NULL, 0 },
{ "find-new", cmd_find_new, cmd_find_new_usage, NULL, 0 },
{ "show", cmd_subvol_show, cmd_subvol_show_usage, NULL, 0 },
+ { "sync", cmd_subvol_sync, cmd_subvol_sync_usage, NULL, 0 },
NULL_CMD_STRUCT
}
};
--
1.8.4.5
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