[libvirt] [PATCH 2/2] storage: Polling the sysfs for pool with "fc_host" type adapter

The SCSI device corresponding to the vHBA might not show up in sysfs yet when we trying to scan the LUNs. As a result, we will end up with an empty volume set for the pool after pool-start, even if there are LUNs. Though the time of the device showing up is rather depended, better than doing nothing, this patch introduces the polling with 5 * 1 seconds in maximum (the time works fine on my testing machine at least). Note that for the pool which doesn't have any LUN, it will still take 5 seconds to poll, but it's not a bad trade, 5 seconds is not much, and in most cases, one won't use an empty pool in practice. --- src/storage/storage_backend_scsi.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/src/storage/storage_backend_scsi.c b/src/storage/storage_backend_scsi.c index 93039c1..2efcdb8 100644 --- a/src/storage/storage_backend_scsi.c +++ b/src/storage/storage_backend_scsi.c @@ -495,6 +495,8 @@ virStorageBackendSCSIFindLUs(virStoragePoolObjPtr pool, DIR *devicedir = NULL; struct dirent *lun_dirent = NULL; char devicepattern[64]; + bool found = false; + size_t i = 0; VIR_DEBUG("Discovering LUs on host %u", scanhost); @@ -510,6 +512,7 @@ virStorageBackendSCSIFindLUs(virStoragePoolObjPtr pool, snprintf(devicepattern, sizeof(devicepattern), "%u:%%u:%%u:%%u\n", scanhost); +retry: while ((lun_dirent = readdir(devicedir))) { if (sscanf(lun_dirent->d_name, devicepattern, &bus, &target, &lun) != 3) { @@ -518,9 +521,22 @@ virStorageBackendSCSIFindLUs(virStoragePoolObjPtr pool, VIR_DEBUG("Found LU '%s'", lun_dirent->d_name); + found = true; processLU(pool, scanhost, bus, target, lun); } + /* Sleep for 5 seconds in maximum if the pool's source + * adapter type is "fc_host", since the corresponding + * SCSI device might not show up in the sysfs yet. + */ + if (!found && i++ < 5 && + pool->def->source.adapter.type == + VIR_STORAGE_POOL_SOURCE_ADAPTER_TYPE_FC_HOST) { + sleep(1); + rewinddir(devicedir); + goto retry; + } + closedir(devicedir); return retval; -- 1.8.1.4