The multipath storage backend used the device path (e.g., /dev/mapper/mpathX) as the volume key. Device paths can change across reboots when devices are enumerated in a different order.
Use dm_task_get_uuid() to retrieve the device-mapper UUID, which is derived from the underlying hardware identifier and remains stable. Fall back to the device path when a UUID is not available. Signed-off-by: Lucas Amaral <[email protected]> --- Build-tested and passed full test suite on CentOS Stream 9 (226 OK, 0 failures). Verified dm_task_get_uuid() behavior using a standalone C program that mimics the patched vol->key logic, run against simulated device-mapper devices in a privileged container: $ dmsetup create testmpath0 \ -u "mpath-3600508b4000c4a5d0000300000490000" \ --table "0 1000 zero" $ dmsetup create testmpath1 --table "0 1000 zero" Results: Device: testmpath0 vol->key = mpath-3600508b4000c4a5d0000300000490000 (UUID) Device: testmpath1 (no UUID set) vol->key = /dev/mapper/testmpath1 (path fallback) Device: nonexistent vol->key = /dev/mapper/nonexistent (path fallback) All three cases (UUID present, UUID absent, device missing) behave correctly. Not tested with a running libvirtd and a real mpath pool. --- src/storage/storage_backend_mpath.c | 48 +++++++++++++++++++++++------ 1 file changed, 38 insertions(+), 10 deletions(-) diff --git a/src/storage/storage_backend_mpath.c b/src/storage/storage_backend_mpath.c index 9fc3983c52..a36400502f 100644 --- a/src/storage/storage_backend_mpath.c +++ b/src/storage/storage_backend_mpath.c @@ -40,13 +40,43 @@ VIR_LOG_INIT("storage.storage_backend_mpath"); +static int +virStorageBackendGetDeviceUUID(const char *dev_name, char **uuid) +{ + int ret = -1; + struct dm_task *dmt; + const char *dm_uuid; + + if (!(dmt = dm_task_create(DM_DEVICE_INFO))) + goto out; + + if (!dm_task_set_name(dmt, dev_name)) + goto out; + + if (!dm_task_run(dmt)) + goto out; + + if (!(dm_uuid = dm_task_get_uuid(dmt)) || !*dm_uuid) + goto out; + + *uuid = g_strdup(dm_uuid); + ret = 0; + + out: + if (dmt != NULL) + dm_task_destroy(dmt); + return ret; +} + + static int virStorageBackendMpathNewVol(virStoragePoolObj *pool, const int devnum, - const char *dev) + const char *dev_name) { virStoragePoolDef *def = virStoragePoolObjGetDef(pool); g_autoptr(virStorageVolDef) vol = NULL; + g_autofree char *dev_uuid = NULL; vol = g_new0(virStorageVolDef, 1); @@ -54,15 +84,18 @@ virStorageBackendMpathNewVol(virStoragePoolObj *pool, (vol->name) = g_strdup_printf("dm-%u", devnum); - vol->target.path = g_strdup_printf("/dev/%s", dev); + vol->target.path = g_strdup_printf("/dev/mapper/%s", dev_name); if (virStorageBackendUpdateVolInfo(vol, true, VIR_STORAGE_VOL_OPEN_DEFAULT, 0) < 0) { return -1; } - /* XXX should use logical unit's UUID instead */ - vol->key = g_strdup(vol->target.path); + virStorageBackendGetDeviceUUID(dev_name, &dev_uuid); + if (dev_uuid) + vol->key = g_steal_pointer(&dev_uuid); + else + vol->key = g_strdup(vol->target.path); if (virStoragePoolObjAddVol(pool, vol) < 0) return -1; @@ -151,7 +184,6 @@ virStorageBackendCreateVols(virStoragePoolObj *pool, { uint32_t minor = -1; uint32_t next; - g_autofree char *map_device = NULL; do { int is_mpath = virStorageBackendIsMultipath(names->name); @@ -161,8 +193,6 @@ virStorageBackendCreateVols(virStoragePoolObj *pool, if (is_mpath == 1) { - map_device = g_strdup_printf("mapper/%s", names->name); - if (virStorageBackendGetMinorNumber(names->name, &minor) < 0) { virReportError(VIR_ERR_INTERNAL_ERROR, _("Failed to get %1$s minor number"), @@ -170,10 +200,8 @@ virStorageBackendCreateVols(virStoragePoolObj *pool, return -1; } - if (virStorageBackendMpathNewVol(pool, minor, map_device) < 0) + if (virStorageBackendMpathNewVol(pool, minor, names->name) < 0) return -1; - - VIR_FREE(map_device); } /* Given the way libdevmapper returns its data, I don't see -- 2.52.0
