It is possible to write a UDEV rule/script in userspace to active the
same result, if desired,
but there are several cases where this is undesirable so I do not
think the kernel should do it.
Having userspace handle policy decisions allows for more flexibility.
-Ewan
On Fri, Jan 14, 2022 at 5:03 PM Brian Bunker <brian@xxxxxxxxxxxxxxx> wrote:
>
> When a new volume is added to an ACL list for a host and a unit
> attention is posted for that host ASC=0x3f ASCQ=0x0e, REPORTED LUNS
> DATA HAS CHANGED, devices are created if the udev rule is active:
>
> ACTION=="change", SUBSYSTEM=="scsi",
> ENV{SDEV_UA}=="REPORTED_LUNS_DATA_HAS_CHANGED",
> RUN+="scan-scsi-target $env{DEVPATH}"
>
> However when a volume is deleted from the ACL list for a host, those
> devices are not deleted. They are orphaned. I am showing multpath
> output to show the connected devices pre-removal from the ACL list and
> post:
>
> Before:
> [root@init501-9 rules.d]# multipath -ll
> 3624a9370d5779477e526433100011019 dm-2 PURE ,FlashArray
> size=2.0T features='0' hwhandler='1 alua' wp=rw
> `-+- policy='service-time 0' prio=50 status=active
> |- 0:0:1:1 sdb 8:16 active ready running
> |- 7:0:1:1 sdc 8:32 active ready running
> |- 8:0:1:1 sdd 8:48 active ready running
> `- 9:0:1:1 sde 8:64 active ready running
>
> [root@init501-9 rules.d]# sg_inq -p 0x80 /dev/sdb
> VPD INQUIRY: Unit serial number page
> Unit serial number: D5779477E526433100011019
> [root@init501-9 rules.d]# sg_inq -p 0x80 /dev/sdc
> VPD INQUIRY: Unit serial number page
> Unit serial number: D5779477E526433100011019
> [root@init501-9 rules.d]# sg_inq -p 0x80 /dev/sdd
> VPD INQUIRY: Unit serial number page
> Unit serial number: D5779477E526433100011019
> [root@init501-9 rules.d]# sg_inq -p 0x80 /dev/sde
> VPD INQUIRY: Unit serial number page
> Unit serial number: D5779477E526433100011019
>
> After:
> [root@init501-9 rules.d]# multipath -ll
> 3624a9370d5779477e526433100011019 dm-2 PURE ,FlashArray
> size=2.0T features='0' hwhandler='1 alua' wp=rw
> `-+- policy='service-time 0' prio=0 status=enabled
> |- 0:0:1:1 sdb 8:16 failed faulty running
> |- 7:0:1:1 sdc 8:32 failed faulty running
> |- 8:0:1:1 sdd 8:48 failed faulty running
> `- 9:0:1:1 sde 8:64 failed faulty running
> [root@init501-9 rules.d]# sg_map -i -x
> /dev/sg0 1 0 0 0 0 /dev/sda ATA TOSHIBA THNSNH25 N101
> /dev/sg1 0 0 1 1 0 /dev/sdb
> /dev/sg2 7 0 1 1 0 /dev/sdc
> /dev/sg3 8 0 1 1 0 /dev/sdd
> /dev/sg4 9 0 1 1 0 /dev/sde
>
> Now if a new volume is connected, different serial number same LUN, it
> will use those orphaned devices:
>
> [root@init501-9 rules.d]# multipath -ll
> 3624a9370d5779477e526433100011019 dm-2 PURE ,FlashArray
> size=2.0T features='0' hwhandler='1 alua' wp=rw
> `-+- policy='service-time 0' prio=50 status=active
> |- 0:0:1:1 sdb 8:16 active ready running
> |- 7:0:1:1 sdc 8:32 active ready running
> |- 8:0:1:1 sdd 8:48 active ready running
> `- 9:0:1:1 sde 8:64 active ready running
>
> [root@init501-9 rules.d]# sg_inq -p 0x80 /dev/sdb
> VPD INQUIRY: Unit serial number page
> Unit serial number: D5779477E52643310001101A
> [root@init501-9 rules.d]# sg_inq -p 0x80 /dev/sdc
> VPD INQUIRY: Unit serial number page
> Unit serial number: D5779477E52643310001101A
> [root@init501-9 rules.d]# sg_inq -p 0x80 /dev/sdd
> VPD INQUIRY: Unit serial number page
> Unit serial number: D5779477E52643310001101A
> [root@init501-9 rules.d]# sg_inq -p 0x80 /dev/sde
> VPD INQUIRY: Unit serial number page
> Unit serial number: D5779477E52643310001101A
>
> This situation becomes more problematic if multiple target devices are
> presenting the same volume and each target device has its own ACL
> management, we can end up in situations where some paths have one
> serial number and some have another.
>
> [root@init501-9 rules.d]# multipath -ll
> 3624a9370d5779477e52643310001101b dm-2 PURE ,FlashArray
> size=2.0T features='0' hwhandler='1 alua' wp=rw
> `-+- policy='service-time 0' prio=50 status=active
> |- 0:0:0:1 sdf 8:80 active ready running
> |- 7:0:0:1 sdg 8:96 active ready running
> |- 8:0:0:1 sdh 8:112 active ready running
> |- 9:0:0:1 sdi 8:128 active ready running
> |- 0:0:1:1 sdb 8:16 active ready running
> |- 7:0:1:1 sdc 8:32 active ready running
> |- 8:0:1:1 sdd 8:48 active ready running
> `- 9:0:1:1 sde 8:64 active ready running
>
> [root@init501-9 rules.d]# sg_inq -p 0x80 /dev/sdb
> VPD INQUIRY: Unit serial number page
> Unit serial number: D5779477E52643310001101B
> [root@init501-9 rules.d]# sg_inq -p 0x80 /dev/sdc
> VPD INQUIRY: Unit serial number page
> Unit serial number: D5779477E52643310001101B
> [root@init501-9 rules.d]# sg_inq -p 0x80 /dev/sdd
> VPD INQUIRY: Unit serial number page
> Unit serial number: D5779477E52643310001101B
> [root@init501-9 rules.d]# sg_inq -p 0x80 /dev/sde
> VPD INQUIRY: Unit serial number page
> Unit serial number: D5779477E52643310001101B
> [root@init501-9 rules.d]# sg_inq -p 0x80 /dev/sdf
> VPD INQUIRY: Unit serial number page
> Unit serial number: D5779477E52643310001101C
> [root@init501-9 rules.d]# sg_inq -p 0x80 /dev/sdg
> VPD INQUIRY: Unit serial number page
> Unit serial number: D5779477E52643310001101C
> [root@init501-9 rules.d]# sg_inq -p 0x80 /dev/sdh
> VPD INQUIRY: Unit serial number page
> Unit serial number: D5779477E52643310001101C
> [root@init501-9 rules.d]# sg_inq -p 0x80 /dev/sdi
> VPD INQUIRY: Unit serial number page
> Unit serial number: D5779477E52643310001101C
>
> I understand that this situation can be avoided with a rescan that
> purges stale disks when an ACL is removed like rescan-scsi-bus.sh -r.
> But the ACL removal itself does initiate a rescan, it is just that
> rescan doesn't have the ability to purge devices whose LUNs are no
> longer returned in the reported LUN list.
>
> Signed-off-by: Seamus Conorr <jsconnor@xxxxxxxxxxxxxxx>
> Signed-off-by: Krishna Kant <krishna.kant@xxxxxxxxxxxxxxx>
> Signed-off-by: Krishna Kant <yokim@xxxxxxxxxxxxxxx>
> __
> diff --git a/drivers/scsi/scsi_devinfo.c b/drivers/scsi/scsi_devinfo.c
> index c7080454aea9..cfc6c3cc2996 100644
> --- a/drivers/scsi/scsi_devinfo.c
> +++ b/drivers/scsi/scsi_devinfo.c
> @@ -220,6 +220,7 @@ static struct {
> {"PIONEER", "CD-ROM DRM-624X", NULL, BLIST_FORCELUN | BLIST_SINGLELUN},
> {"Promise", "VTrak E610f", NULL, BLIST_SPARSELUN | BLIST_NO_RSOC},
> {"Promise", "", NULL, BLIST_SPARSELUN},
> + {"PURE", "FlashArray", "*", BLIST_REMOVE_STALE},
> {"QEMU", "QEMU CD-ROM", NULL, BLIST_SKIP_VPD_PAGES},
> {"QNAP", "iSCSI Storage", NULL, BLIST_MAX_1024},
> {"SYNOLOGY", "iSCSI Storage", NULL, BLIST_MAX_1024},
> diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
> index 3520b9384428..15f6d8a9b61b 100644
> --- a/drivers/scsi/scsi_scan.c
> +++ b/drivers/scsi/scsi_scan.c
> @@ -1102,6 +1102,7 @@ static int scsi_probe_and_add_lun(struct
> scsi_target *starget,
> */
> sdev = scsi_device_lookup_by_target(starget, lun);
> if (sdev) {
> + sdev->in_lun_list = 1;
> if (rescan != SCSI_SCAN_INITIAL || !scsi_device_created(sdev)) {
> SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
> "scsi scan: device exists on %s\n",
> @@ -1198,6 +1199,7 @@ static int scsi_probe_and_add_lun(struct
> scsi_target *starget,
> }
>
> res = scsi_add_lun(sdev, result, &bflags, shost->async_scan);
> + sdev->in_lun_list = 1;
> if (res == SCSI_SCAN_LUN_PRESENT) {
> if (bflags & BLIST_KEY) {
> sdev->lockable = 0;
> @@ -1309,6 +1311,23 @@ static void scsi_sequential_lun_scan(struct
> scsi_target *starget,
> return;
> }
>
> +static void
> +_reset_lun_list(struct scsi_device *sdev, void *data)
> +{
> + if (sdev->is_visible) {
> + sdev->in_lun_list = 0;
> + }
> +}
> +
> +static void
> +_remove_stale_devices(struct scsi_device *sdev, void *data)
> +{
> + if (sdev->in_lun_list || sdev->is_visible == 0)
> + return;
> + __scsi_remove_device(sdev);
> + sdev_printk(KERN_INFO, sdev, "lun_scan: Stale\n");
> +}
> +
> /**
> * scsi_report_lun_scan - Scan using SCSI REPORT LUN results
> * @starget: which target
> @@ -1373,6 +1392,9 @@ static int scsi_report_lun_scan(struct
> scsi_target *starget, blist_flags_t bflag
> }
> }
>
> + if (bflags & BLIST_REMOVE_STALE)
> + starget_for_each_device(starget, NULL, _reset_lun_list);
> +
> /*
> * Allocate enough to hold the header (the same size as one scsi_lun)
> * plus the number of luns we are requesting. 511 was the default
> @@ -1487,6 +1509,9 @@ static int scsi_report_lun_scan(struct
> scsi_target *starget, blist_flags_t bflag
> }
> }
>
> + if (bflags & BLIST_REMOVE_STALE)
> + starget_for_each_device(starget, NULL, _remove_stale_devices);
> +
> out_err:
> kfree(lun_data);
> out:
> diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
> index ab7557d84f75..c5446ee73af6 100644
> --- a/include/scsi/scsi_device.h
> +++ b/include/scsi/scsi_device.h
> @@ -206,6 +206,7 @@ struct scsi_device {
> unsigned rpm_autosuspend:1; /* Enable runtime autosuspend at device
> * creation time */
> unsigned ignore_media_change:1; /* Ignore MEDIA CHANGE on resume */
> + unsigned in_lun_list:1; /* contained in report luns response */
>
> unsigned int queue_stopped; /* request queue is quiesced */
> bool offline_already; /* Device offline message logged */
> diff --git a/include/scsi/scsi_devinfo.h b/include/scsi/scsi_devinfo.h
> index 5d14adae21c7..2e620ca2b7bc 100644
> --- a/include/scsi/scsi_devinfo.h
> +++ b/include/scsi/scsi_devinfo.h
> @@ -68,8 +68,10 @@
> #define BLIST_RETRY_ITF ((__force blist_flags_t)(1ULL << 32))
> /* Always retry ABORTED_COMMAND with ASC 0xc1 */
> #define BLIST_RETRY_ASC_C1 ((__force blist_flags_t)(1ULL << 33))
> +/* Remove devices no longer in reported luns data */
> +#define BLIST_REMOVE_STALE ((__force blist_flags_t)(1ULL << 34))
>
> -#define __BLIST_LAST_USED BLIST_RETRY_ASC_C1
> +#define __BLIST_LAST_USED BLIST_REMOVE_STALE
>
> #define __BLIST_HIGH_UNUSED (~(__BLIST_LAST_USED | \
> (__force blist_flags_t) \
>
>
>
>
> --
> Brian Bunker
> PURE Storage, Inc.
> brian@xxxxxxxxxxxxxxx
>
