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/*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include "kerncompat.h"
#include <stdbool.h>
#include <string.h>
#include <uuid/uuid.h>
#include "kernel-shared/ctree.h"
#include "kernel-shared/transaction.h"
#include "common/messages.h"
#include "tune/tune.h"
#include "ioctl.h"
int set_metadata_uuid(struct btrfs_root *root, const char *uuid_string)
{
struct btrfs_super_block *disk_super;
uuid_t new_fsid, unused1, unused2;
struct btrfs_trans_handle *trans;
bool new_uuid = true;
u64 incompat_flags;
bool uuid_changed;
u64 super_flags;
int ret;
disk_super = root->fs_info->super_copy;
super_flags = btrfs_super_flags(disk_super);
incompat_flags = btrfs_super_incompat_flags(disk_super);
uuid_changed = incompat_flags & BTRFS_FEATURE_INCOMPAT_METADATA_UUID;
if (super_flags & BTRFS_SUPER_FLAG_SEEDING) {
error("cannot set metadata UUID on a seed device");
return 1;
}
if (check_unfinished_fsid_change(root->fs_info, unused1, unused2)) {
error("UUID rewrite in progress, cannot change metadata_uuid");
return 1;
}
if (uuid_string)
uuid_parse(uuid_string, new_fsid);
else
uuid_generate(new_fsid);
new_uuid = (memcmp(new_fsid, disk_super->fsid, BTRFS_FSID_SIZE) != 0);
/* Step 1 sets the in progress flag */
trans = btrfs_start_transaction(root, 1);
super_flags |= BTRFS_SUPER_FLAG_CHANGING_FSID_V2;
btrfs_set_super_flags(disk_super, super_flags);
ret = btrfs_commit_transaction(trans, root);
if (ret < 0)
return ret;
if (new_uuid && uuid_changed && memcmp(disk_super->metadata_uuid,
new_fsid, BTRFS_FSID_SIZE) == 0) {
/*
* Changing fsid to be the same as metadata uuid, so just
* disable the flag
*/
memcpy(disk_super->fsid, &new_fsid, BTRFS_FSID_SIZE);
incompat_flags &= ~BTRFS_FEATURE_INCOMPAT_METADATA_UUID;
btrfs_set_super_incompat_flags(disk_super, incompat_flags);
memset(disk_super->metadata_uuid, 0, BTRFS_FSID_SIZE);
} else if (new_uuid && uuid_changed && memcmp(disk_super->metadata_uuid,
new_fsid, BTRFS_FSID_SIZE)) {
/*
* Changing fsid on an already changed FS, in this case we
* only change the fsid and don't touch metadata uuid as it
* has already the correct value
*/
memcpy(disk_super->fsid, &new_fsid, BTRFS_FSID_SIZE);
} else if (new_uuid && !uuid_changed) {
/*
* First time changing the fsid, copy the fsid to metadata_uuid
*/
incompat_flags |= BTRFS_FEATURE_INCOMPAT_METADATA_UUID;
btrfs_set_super_incompat_flags(disk_super, incompat_flags);
memcpy(disk_super->metadata_uuid, disk_super->fsid,
BTRFS_FSID_SIZE);
memcpy(disk_super->fsid, &new_fsid, BTRFS_FSID_SIZE);
} else {
/* Setting the same fsid as current, do nothing */
return 0;
}
trans = btrfs_start_transaction(root, 1);
/*
* Step 2 is to write the metadata_uuid, set the incompat flag and
* clear the in progress flag
*/
super_flags &= ~BTRFS_SUPER_FLAG_CHANGING_FSID_V2;
btrfs_set_super_flags(disk_super, super_flags);
/* Then actually copy the metadata uuid and set the incompat bit */
return btrfs_commit_transaction(trans, root);
}
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