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Create unique partition labels

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When partitioning a device a name may be specified for each partition.
Internally zfs doesn't use this partition name for anything so it
has always just been set to "zfs".

However this isn't optimal because udev will create symlinks using
this name in /dev/disk/by-partlabel/.  If the name isn't unique
then all the links cannot be created.

Therefore a random 64-bit value has been added to the partition
label, i.e "zfs-1234567890abcdef".  Additional information could
be encoded here but since partitions may be reused that might
result in confusion and it was decided against.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes #4517
This commit is contained in:
Brian Behlendorf 2016-04-13 14:50:16 -07:00
parent a5a370227e
commit 5b4136bd49
2 changed files with 28 additions and 1 deletions
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1
cmd/zpool/zpool_main.c
View File

@ -6055,6 +6055,7 @@ main(int argc, char **argv)
(void) setlocale(LC_ALL, "");
(void) textdomain(TEXT_DOMAIN);
srand(time(NULL));
dprintf_setup(&argc, argv);

28
lib/libzfs/libzfs_pool.c
View File

@ -4170,6 +4170,32 @@ zpool_label_disk_check(char *path)
return (0);
}
/*
* Generate a unique partition name for the ZFS member. Partitions must
* have unique names to ensure udev will be able to create symlinks under
* /dev/disk/by-partlabel/ for all pool members. The partition names are
* of the form <pool>-<unique-id>.
*/
static void
zpool_label_name(char *label_name, int label_size)
{
uint64_t id = 0;
int fd;
fd = open("/dev/urandom", O_RDONLY);
if (fd > 0) {
if (read(fd, &id, sizeof (id)) != sizeof (id))
id = 0;
close(fd);
}
if (id == 0)
id = (((uint64_t)rand()) << 32) | (uint64_t)rand();
snprintf(label_name, label_size, "zfs-%016llx", (u_longlong_t) id);
}
/*
* Label an individual disk. The name provided is the short name,
* stripped of any leading /dev path.
@ -4260,7 +4286,7 @@ zpool_label_disk(libzfs_handle_t *hdl, zpool_handle_t *zhp, char *name)
* can get, in the absence of V_OTHER.
*/
vtoc->efi_parts[0].p_tag = V_USR;
(void) strcpy(vtoc->efi_parts[0].p_name, "zfs");
zpool_label_name(vtoc->efi_parts[0].p_name, EFI_PART_NAME_LEN);
vtoc->efi_parts[8].p_start = slice_size + start_block;
vtoc->efi_parts[8].p_size = resv;