Allow the specification of the filesystem UUID at mkfs time.
Non-unique unique IDs are rejected. This includes attempting
to re-mkfs with the same UUID; if you really want to do that,
you can mkfs with a new UUID, then re-mkfs with the one you
wanted. ;)
(Implemented only for mkfs.btrfs, not btrfs-convert).
Signed-off-by: Eric Sandeen <sand...@redhat.com>
---
NB: the prior patch didn't work well if you re-mkfs'd with
the same UUID; to be honest I didn't get to the bottom of it,
but the fact that that old UUID was already in an internal
list of present devices seems to have confused things.
V2: reject non-unique unique IDs.
V3: test for non-unique unique IDs early in mkfs.
diff --git a/btrfs-convert.c b/btrfs-convert.c
index a8b2c51..d62d4f8 100644
--- a/btrfs-convert.c
+++ b/btrfs-convert.c
@@ -2240,7 +2240,7 @@ static int do_convert(const char *devname, int datacsum,
int packing,
goto fail;
}
ret = make_btrfs(fd, devname, ext2_fs->super->s_volume_name,
- blocks, total_bytes, blocksize, blocksize,
+ NULL, blocks, total_bytes, blocksize, blocksize,
blocksize, blocksize, 0);
if (ret) {
fprintf(stderr, "unable to create initial ctree: %s\n",
diff --git a/man/mkfs.btrfs.8.in b/man/mkfs.btrfs.8.in
index bef509d..4450d03 100644
--- a/man/mkfs.btrfs.8.in
+++ b/man/mkfs.btrfs.8.in
@@ -16,6 +16,7 @@ mkfs.btrfs \- create a btrfs filesystem
[ \fB\-r\fP\fI rootdir\fP ]
[ \fB\-K\fP ]
[ \fB\-O\fP\fI feature1,feature2,...\fP ]
+[ \fB\-U\fP\fI uuid\fP ]
[ \fB\-h\fP ]
[ \fB\-V\fP ]
\fI device\fP [ \fIdevice ...\fP ]
@@ -90,6 +91,9 @@ To see all run
\fBmkfs.btrfs -O list-all\fR
.TP
+\fB\-U\fR, \fB\-\-uuid \fR
+Create the filesystem with the specified UUID, which must not already exist on
the system.
+.TP
\fB\-V\fR, \fB\-\-version\fR
Print the \fBmkfs.btrfs\fP version and exit.
.SH UNIT
diff --git a/mkfs.c b/mkfs.c
index dbd83f5..d67a5ba 100644
--- a/mkfs.c
+++ b/mkfs.c
@@ -288,6 +288,7 @@ static void print_usage(void)
fprintf(stderr, "\t -r --rootdir the source directory\n");
fprintf(stderr, "\t -K --nodiscard do not perform whole device TRIM\n");
fprintf(stderr, "\t -O --features comma separated list of filesystem
features\n");
+ fprintf(stderr, "\t -U --uuid specify the filesystem UUID\n");
fprintf(stderr, "\t -V --version print the mkfs.btrfs version and
exit\n");
fprintf(stderr, "%s\n", BTRFS_BUILD_VERSION);
exit(1);
@@ -351,6 +352,7 @@ static struct option long_options[] = {
{ "rootdir", 1, NULL, 'r' },
{ "nodiscard", 0, NULL, 'K' },
{ "features", 0, NULL, 'O' },
+ { "uuid", 0, NULL, 'U' },
{ NULL, 0, NULL, 0}
};
@@ -1273,11 +1275,12 @@ int main(int ac, char **av)
int dev_cnt = 0;
int saved_optind;
char estr[100];
+ char *fs_uuid = NULL;
u64 features = DEFAULT_MKFS_FEATURES;
while(1) {
int c;
- c = getopt_long(ac, av, "A:b:fl:n:s:m:d:L:O:r:VMK",
+ c = getopt_long(ac, av, "A:b:fl:n:s:m:d:L:O:r:U:VMK",
long_options, &option_index);
if (c < 0)
break;
@@ -1346,6 +1349,9 @@ int main(int ac, char **av)
source_dir = optarg;
source_dir_set = 1;
break;
+ case 'U':
+ fs_uuid = optarg;
+ break;
case 'K':
discard = 0;
break;
@@ -1368,6 +1374,20 @@ int main(int ac, char **av)
"The -r option is limited to a single device\n");
exit(1);
}
+
+ if (fs_uuid) {
+ uuid_t dummy_uuid;
+
+ if (uuid_parse(fs_uuid, dummy_uuid) != 0) {
+ fprintf(stderr, "could not parse UUID: %s\n", fs_uuid);
+ exit(1);
+ }
+ if (!test_uuid_unique(fs_uuid)) {
+ fprintf(stderr, "non-unique UUID: %s\n", fs_uuid);
+ exit(1);
+ }
+ }
+
while (dev_cnt-- > 0) {
file = av[optind++];
if (is_block_device(file))
@@ -1514,7 +1534,7 @@ int main(int ac, char **av)
process_fs_features(features);
- ret = make_btrfs(fd, file, label, blocks, dev_block_count,
+ ret = make_btrfs(fd, file, label, fs_uuid, blocks, dev_block_count,
nodesize, leafsize,
sectorsize, stripesize, features);
if (ret) {
diff --git a/utils.c b/utils.c
index 3e9c527..cfac0d4 100644
--- a/utils.c
+++ b/utils.c
@@ -93,12 +93,41 @@ static u64 reference_root_table[] = {
[6] = BTRFS_CSUM_TREE_OBJECTID,
};
-int make_btrfs(int fd, const char *device, const char *label,
+int test_uuid_unique(char *fs_uuid)
+{
+ int unique = 1;
+ blkid_dev_iterate iter = NULL;
+ blkid_dev dev = NULL;
+ blkid_cache cache = NULL;
+
+ if (blkid_get_cache(&cache, 0) < 0) {
+ printf("ERROR: lblkid cache get failed\n");
+ return 1;
+ }
+ blkid_probe_all(cache);
+ iter = blkid_dev_iterate_begin(cache);
+ blkid_dev_set_search(iter, "UUID", fs_uuid);
+
+ while (blkid_dev_next(iter, &dev) == 0) {
+ dev = blkid_verify(cache, dev);
+ if (dev) {
+ unique = 0;
+ break;
+ }
+ }
+
+ blkid_dev_iterate_end(iter);
+ blkid_put_cache(cache);
+
+ return unique;
+}
+
+int make_btrfs(int fd, const char *device, const char *label, char *fs_uuid,
u64 blocks[7], u64 num_bytes, u32 nodesize,
u32 leafsize, u32 sectorsize, u32 stripesize, u64 features)
{
struct btrfs_super_block super;
- struct extent_buffer *buf;
+ struct extent_buffer *buf = NULL;
struct btrfs_root_item root_item;
struct btrfs_disk_key disk_key;
struct btrfs_extent_item *extent_item;
@@ -125,7 +154,20 @@ int make_btrfs(int fd, const char *device, const char
*label,
memset(&super, 0, sizeof(super));
num_bytes = (num_bytes / sectorsize) * sectorsize;
- uuid_generate(super.fsid);
+ if (fs_uuid) {
+ if (uuid_parse(fs_uuid, super.fsid) != 0) {
+ fprintf(stderr, "could not parse UUID: %s\n", fs_uuid);
+ ret = -EINVAL;
+ goto out;
+ }
+ if (!test_uuid_unique(fs_uuid)) {
+ fprintf(stderr, "non-unique UUID: %s\n", fs_uuid);
+ ret = -EBUSY;
+ goto out;
+ }
+ } else {
+ uuid_generate(super.fsid);
+ }
uuid_generate(super.dev_item.uuid);
uuid_generate(chunk_tree_uuid);
diff --git a/utils.h b/utils.h
index 3c62066..4a404ae 100644
--- a/utils.h
+++ b/utils.h
@@ -39,8 +39,9 @@
#define BTRFS_UUID_UNPARSED_SIZE 37
+int test_uuid_unique(char *fs_uuid);
int make_btrfs(int fd, const char *device, const char *label,
- u64 blocks[6], u64 num_bytes, u32 nodesize,
+ char *fs_uuid, u64 blocks[6], u64 num_bytes, u32 nodesize,
u32 leafsize, u32 sectorsize, u32 stripesize, u64 features);
int btrfs_make_root_dir(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 objectid);
--
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