Re: [Libguestfs] [PATCH v3.1 1/9] uuid: add support to change uuid of btrfs partition

btrfs-progs v4.1 add support to change uuid of btrfs fs. Signed-off-by: Chen Hanxiao <chenhanxiao(a)cn.fujitsu.com&gt; --- v3.1: fix a typo v3: set errno as ENOTSUP when btrfstune -u is not available v2: put btrfs operation back to daemon/btrfs.c move tests to tests/btrfs daemon/btrfs.c | 60 ++++++++++++++++++++++++++++++++++++++++++ daemon/daemon.h | 1 + daemon/uuids.c | 6 ++--- tests/btrfs/test-btrfs-misc.pl | 17 ++++++++++++ 4 files changed, 80 insertions(+), 4 deletions(-) diff --git a/daemon/btrfs.c b/daemon/btrfs.c index 20e5e6b..a69c512 100644 --- a/daemon/btrfs.c +++ b/daemon/btrfs.c @@ -790,6 +790,44 @@ do_btrfs_device_delete (char *const *devices, const char *fs) return 0; } + +/* btrfstune command add two new options + * -U UUID change fsid to UUID + * -u change fsid, use a random one + * since v4.1 + * We could check wheter 'btrfstune' support + * '-u' and '-U UUID' option by checking the output of + * 'btrfstune' command. + */ +static int +test_btrfstune_uuid_opt (void) +{ + static int result = -1; + if (result != -1) + return result; + + CLEANUP_FREE char *err = NULL; + + int r = commandr (NULL, &err, str_btrfstune, NULL); + + if (r == -1) { + reply_with_error ("btrfstune: %s", err); + return -1; + } + + /* FIXME currently btrfstune do not support '--help'.

+ * If got an invalid options, it will print its usage + * in stderr. + * We had to check it there. + */ + if (strstr (err, "-U") == NULL || strstr (err, "-u") == NULL) + result = 0; + else + result = 1; + + return result; +} + int do_btrfs_set_seeding (const char *device, int svalue) { @@ -807,6 +845,28 @@ do_btrfs_set_seeding (const char *device, int svalue) return 0; } +int +btrfs_set_uuid (const char *device, const char *uuid) +{ + CLEANUP_FREE char *err = NULL; + int r; + int has_uuid_opts = test_btrfstune_uuid_opt (); + + if (has_uuid_opts <= 0) { + reply_with_error_errno (ENOTSUP, "btrfs filesystems' UUID cannot be changed"); + return -1; + } + + r = commandr (NULL, &err, str_btrfstune, "-f", "-U", uuid, device, NULL); + + if (r == -1) { + reply_with_error ("%s: %s", device, err); + return -1; + } + + return 0; +} + /* Takes optional arguments, consult optargs_bitmask. */ int do_btrfs_fsck (const char *device, int64_t superblock, int repair) diff --git a/daemon/daemon.h b/daemon/daemon.h index 136e9a9..b74ba3c 100644 --- a/daemon/daemon.h +++ b/daemon/daemon.h @@ -268,6 +268,7 @@ extern char *debug_bmap_device (const char *subcmd, size_t argc, char *const *co /*-- in btrfs.c --*/ extern char *btrfs_get_label (const char *device); +extern int btrfs_set_uuid (const char *device, const char *uuid); /*-- in ntfs.c --*/ extern char *ntfs_get_label (const char *device); diff --git a/daemon/uuids.c b/daemon/uuids.c index 06b33e9..f98d8e5 100644 --- a/daemon/uuids.c +++ b/daemon/uuids.c @@ -110,10 +110,8 @@ do_set_uuid (const char *device, const char *uuid) else if (STREQ (vfs_type, "swap")) r = swapuuid (device, uuid); - else if (STREQ (vfs_type, "btrfs")) { - reply_with_error ("btrfs filesystems' UUID cannot be changed"); - r = -1; - } + else if (STREQ (vfs_type, "btrfs")) + r = btrfs_set_uuid (device, uuid); else { reply_with_error ("don't know how to set the UUID for '%s' filesystems", diff --git a/tests/btrfs/test-btrfs-misc.pl b/tests/btrfs/test-btrfs-misc.pl index 2fe7c59..b47caab 100755 --- a/tests/btrfs/test-btrfs-misc.pl +++ b/tests/btrfs/test-btrfs-misc.pl @@ -20,6 +20,7 @@ use strict; use warnings; +use Errno; use Sys::Guestfs; @@ -47,5 +48,21 @@ my $label = $g->vfs_label ("/dev/sda1"); die "unexpected label: expecting 'newlabel' but got '$label'" unless $label eq "newlabel"; +# Setting btrfs UUID +eval { + $g->set_uuid ("/dev/sda1", "12345678-1234-1234-1234-123456789012"); +}; +# FIXME: ignore ESRCH

+my $err = $g->last_errno (); + +if ($err == 0) { + my $uuid = $g->vfs_uuid ("/dev/sda1"); + die "unexpected uuid expecting + '12345678-1234-1234-1234-123456789012' but got '$uuid'" + unless $uuid eq "12345678-1234-1234-1234-123456789012"; +} elsif ($err == Errno::ENOTSUP()) { + warn "$0: skipping test for btrfs UUID change feature is not available\n"; +}