+ n = scandir(sysfs_path, &namelist, notdotdir, versionsort); + if (n <= 0) { + /* we didn't find any reasonable entries; return failure */ + virStorageReportError(conn, VIR_ERR_INTERNAL_ERROR, + _("Failed to find any LUNs for session %s: %s"), + session, strerror(errno)); + + return -1; + } Who told you/anyone who wrote this code before that the 0th lun cannot be a real entry? This assumption is wrong.

>> Who told you/anyone who wrote this code before that the 0th lun cannot >> be a real entry? This assumption is wrong. > Well, that particular piece of code isn't looking at the 0'th LUN, but there is > code below that that is. However, the code here is generally looking for block > devices, and the 0'th LUN is definitely not a block device. Given that, I'm not > sure what else you would want to do with 0th LUN; can you give me some examples? The 0th LUN can be a perfect block device.

Chris Lalancette schreef: > Stefan de Konink wrote: >>>> Who told you/anyone who wrote this code before that the 0th lun >>>> cannot be a real entry? This assumption is wrong. >>> Well, that particular piece of code isn't looking at the 0'th LUN, >>> but there is >>> code below that that is. However, the code here is generally >>> looking for block >>> devices, and the 0'th LUN is definitely not a block device. Given >>> that, I'm not >>> sure what else you would want to do with 0th LUN; can you give me >>> some examples? >> The 0th LUN can be a perfect block device. > > OK, cool, I misunderstood. Given that, can you give me the output of: > > # ls -l /sys/bus/scsi/devices/3:0:0:0 > > Just to make sure I get the right thing?

# cat /sys/bus/scsi/devices/3:0:0:0/model

and # cat /sys/bus/scsi/devices/3:0:0:0/type

from both your netapp target and your sun target? Here, at least, for our "control" LUN, model returns "Controller" while for the real LUNs model returns "VIRTUAL-DISK", so I'm hoping I can distinguish somehow based on what is in model, and if not that, based on type.

Stefan de Konink wrote: > skinkie@xen01 ~ $ ls -l > /sys/devices/platform/host3/session3/target3:0:0/3:0:0:0 > total 0 > lrwxrwxrwx 1 root root 0 May 24 16:38 block:sdar -> > ../../../../../../block/sdar > --w------- 1 root root 4096 Jun 12 16:34 delete > -r--r--r-- 1 root root 4096 Jun 12 16:34 device_blocked > lrwxrwxrwx 1 root root 0 May 24 16:38 driver -> > ../../../../../../bus/scsi/drivers/sd > lrwxrwxrwx 1 root root 0 Jun 12 16:34 generic -> > ../../../../../../class/scsi_generic/sg44 > -r--r--r-- 1 root root 4096 Jun 12 16:34 iocounterbits > -r--r--r-- 1 root root 4096 Jun 12 16:34 iodone_cnt > -r--r--r-- 1 root root 4096 Jun 12 16:34 ioerr_cnt > -r--r--r-- 1 root root 4096 Jun 12 16:34 iorequest_cnt > -r--r--r-- 1 root root 4096 May 24 16:38 model > -rw-r--r-- 1 root root 4096 Jun 12 16:34 queue_depth > -r--r--r-- 1 root root 4096 Jun 12 16:34 queue_type > --w------- 1 root root 4096 Jun 12 16:34 rescan > -r--r--r-- 1 root root 4096 Jun 12 16:34 rev > -r--r--r-- 1 root root 4096 Jun 12 16:34 scsi_level > -rw-r--r-- 1 root root 4096 May 26 11:28 state > lrwxrwxrwx 1 root root 0 May 24 16:38 subsystem -> > ../../../../../../bus/scsi > -rw-r--r-- 1 root root 4096 Jun 12 16:34 timeout > -r--r--r-- 1 root root 4096 May 24 16:38 type > --w------- 1 root root 4096 Jun 12 16:34 uevent > -r--r--r-- 1 root root 4096 May 24 16:38 vendor OK, hopefully just one more request; I'm trying to figure out a way to distinguish a disk from a control LUN, since in my case (Linux iscsi target), 0 is a control LUN. Can you give me the output of: # cat /sys/bus/scsi/devices/3:0:0:0/model and # cat /sys/bus/scsi/devices/3:0:0:0/type from both your netapp target and your sun target? Here, at least, for our "control" LUN, model returns "Controller" while for the real LUNs model returns "VIRTUAL-DISK", so I'm hoping I can distinguish somehow based on what is in model, and if not that, based on type.

> # cat /sys/bus/scsi/devices/3:0:0:0/model > > and > > # cat /sys/bus/scsi/devices/3:0:0:0/type > > from both your netapp target and your sun target? Here, at least, for our > "control" LUN, model returns "Controller" while for the real LUNs model returns > "VIRTUAL-DISK", so I'm hoping I can distinguish somehow based on what is in > model, and if not that, based on type. Can't you distinguish based on the fact that there'll be no /dev/sdNN node for it ?

This rather large patch rewrites the virStorageBackendISCSIFindLUNs() function to only rely on sysfs for finding LUNs, given a session number. Along the way, it also fixes the bug where we wouldn't find LUNs for older kernels (with the block:sda format), and also (possibly) fixes a race condition where we could try to find the LUN before udev has finished connecting it. I say it "possibly" fixes it because I haven't been able to hit it so far, but I definitely need more testing to try and confirm.

+virStorageBackendISCSINewLun(virConnectPtr conn, virStoragePoolObjPtr pool, + unsigned int lun, char *dev)

+ if (strlen(block) == 5) { + /* OK, this is exactly "block"; must be new-style */ + snprintf(sysfs_path, PATH_MAX, + "/sys/bus/scsi/devices/%u:%u:%u:%u/block", + host, bus, target, lun); + sysdir = opendir(sysfs_path); + if (sysdir == NULL) { + virStorageReportError(conn, VIR_ERR_INTERNAL_ERROR, + _("Failed to opendir sysfs path %s: %s"), + sysfs_path, strerror(errno)); + retval = -1; + goto namelist_cleanup; + } + while ((sys_dirent = readdir(sysdir))) { + if (!notdotdir(sys_dirent)) + continue; + + scsidev = strdup(sys_dirent->d_name); + break; + } + closedir(sysdir); + } + else { + /* old-style; just parse out the sd */ + block2 = strrchr(block, ':'); + if (block2 == NULL) { + /* Hm, wasn't what we were expecting; have to give up */ + virStorageReportError(conn, VIR_ERR_INTERNAL_ERROR, + _("Failed to parse block path %s"), + block); + retval = -1; + goto namelist_cleanup; + } + block2++; + scsidev = strdup(block2); + }

+ if (asprintf(&devpath, "/dev/%s", dev) < 0) {

+ retval = virStorageBackendISCSINewLun(conn, pool, lun, scsidev); + if (retval < 0) + break;