btrfs-progs: mkfs: add uuid and otime to ROOT_ITEM of, FS_TREE

Currently, the top-level subvolume lacks the UUID. As a result, both
non-snapshot subvolume and snapshot of top-level subvolume do not have
Parent UUID and cannot be distinguisued. Therefore "fi show" of
top-level lists all the subvolumes which lacks the UUID in
"Snapshot(s)" filed.  Also, it lacks the otime information.

Fix this by adding the UUID and otime at the mkfs time.  As a
consequence, snapshots of top-level subvolume now have a Parent UUID and
UUID tree will create an entry for top-level subvolume at mount time.
This should not cause the problem for current kernel, but user program
which relies on the empty Parent UUID may be affected by this change.

Signed-off-by: Tomohiro Misono <misono.tomohiro@jp.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Misono Tomohiro 2018-03-23 17:16:49 +09:00 committed by David Sterba
parent 30b852cd7e
commit 0a0a03554a
2 changed files with 19 additions and 0 deletions

View File

@ -44,6 +44,7 @@ static int btrfs_create_tree_root(int fd, struct btrfs_mkfs_config *cfg,
u32 itemoff;
int ret = 0;
int blk;
u8 uuid[BTRFS_UUID_SIZE];
memset(buf->data + sizeof(struct btrfs_header), 0,
cfg->nodesize - sizeof(struct btrfs_header));
@ -77,6 +78,19 @@ static int btrfs_create_tree_root(int fd, struct btrfs_mkfs_config *cfg,
btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
btrfs_set_item_size(buf, btrfs_item_nr(nritems),
sizeof(root_item));
if (blk == MKFS_FS_TREE) {
time_t now = time(NULL);
uuid_generate(uuid);
memcpy(root_item.uuid, uuid, BTRFS_UUID_SIZE);
btrfs_set_stack_timespec_sec(&root_item.otime, now);
btrfs_set_stack_timespec_sec(&root_item.ctime, now);
} else {
memset(uuid, 0, BTRFS_UUID_SIZE);
memcpy(root_item.uuid, uuid, BTRFS_UUID_SIZE);
btrfs_set_stack_timespec_sec(&root_item.otime, 0);
btrfs_set_stack_timespec_sec(&root_item.ctime, 0);
}
write_extent_buffer(buf, &root_item,
btrfs_item_ptr_offset(buf, nritems),
sizeof(root_item));

View File

@ -315,6 +315,7 @@ static int create_tree(struct btrfs_trans_handle *trans,
struct btrfs_key location;
struct btrfs_root_item root_item;
struct extent_buffer *tmp;
u8 uuid[BTRFS_UUID_SIZE] = {0};
int ret;
ret = btrfs_copy_root(trans, root, root->node, &tmp, objectid);
@ -325,6 +326,10 @@ static int create_tree(struct btrfs_trans_handle *trans,
btrfs_set_root_bytenr(&root_item, tmp->start);
btrfs_set_root_level(&root_item, btrfs_header_level(tmp));
btrfs_set_root_generation(&root_item, trans->transid);
/* clear uuid and o/ctime of source tree */
memcpy(root_item.uuid, uuid, BTRFS_UUID_SIZE);
btrfs_set_stack_timespec_sec(&root_item.otime, 0);
btrfs_set_stack_timespec_sec(&root_item.ctime, 0);
free_extent_buffer(tmp);
location.objectid = objectid;