On 05/14/2014 07:39 PM, Eric Sandeen wrote: > 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); > + }
My test showed that this detect a false positive when the user tries to mkfs two time on the same device with the same uuid. > + } > + > 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) { This function should skip the check for the devices involved in the mkfs. > + 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; > + } Why a second call to test_uuid_unique(fs_uuid) ? > + } 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); > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- gpg @keyserver.linux.it: Goffredo Baroncelli (kreijackATinwind.it> Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html