scameron@xxxxxxxxxxxxxxxxxx wrote:
I'm seeing a problem which I think is a problem in the SCSI mid layer.
Check this out:
I can rmmod and insmod hpsa (a modified version from
what's currently in the mainline tree, but I don't think
that matters.)
I have one logical drive present
[root@slicer ~]# rmmod hpsa
[root@slicer ~]# insmod /usr/src/linux-2.6.27.42/drivers/scsi/hpsa.ko
[root@slicer ~]# cat /proc/scsi/scsi
Attached devices:
Host: scsi1 Channel: 00 Id: 00 Lun: 00
Vendor: HP Model: 1210m Rev: 0150
Type: RAID ANSI SCSI revision: 05
Host: scsi1 Channel: 00 Id: 00 Lun: 01
Vendor: HP Model: 1210m VOLUME Rev: 0150
Type: Direct-Access ANSI SCSI revision: 05
[root@slicer ~]# rmmod hpsa
[root@slicer ~]# insmod /usr/src/linux-2.6.27.42/drivers/scsi/hpsa.ko
[root@slicer ~]# cat /proc/scsi/scsi
Attached devices:
Host: scsi2 Channel: 00 Id: 00 Lun: 00
Vendor: HP Model: 1210m Rev: 0150
Type: RAID ANSI SCSI revision: 05
Host: scsi2 Channel: 00 Id: 00 Lun: 01
Vendor: HP Model: 1210m VOLUME Rev: 0150
Type: Direct-Access ANSI SCSI revision: 05
[root@slicer ~]# lsscsi -g
[2:0:0:0] storage HP 1210m 0150 - /dev/sg0
[2:0:0:1] disk HP 1210m VOLUME 0150 /dev/sda /dev/sg1
So far, so good.
Now, watch this. Remove the device while something has it open:
[root@slicer ~]# sleep 10 < /dev/sg1 & ( sleep 1 && echo scsi remove-single-device 2 0 0 1 > /proc/scsi/scsi )
[1] 6077
[root@slicer ~]#
[1]+ Done sleep 10 < /dev/sg1
[root@slicer ~]# lsof /dev/sg1
lsof: status error on /dev/sg1: No such file or directory
lsof 4.78
latest revision: ftp://lsof.itap.purdue.edu/pub/tools/unix/lsof/
latest FAQ: ftp://lsof.itap.purdue.edu/pub/tools/unix/lsof/FAQ
latest man page: ftp://lsof.itap.purdue.edu/pub/tools/unix/lsof/lsof_man
usage: [-?abhlnNoOPRstUvVX] [+|-c c] [+|-d s] [+D D] [+|-f]
[-F [f]] [-g [s]] [-i [i]] [+|-L [l]] [+m [m]] [+|-M] [-o [o]]
[-p s] [+|-r [t]] [-S [t]] [-T [t]] [-u s] [+|-w] [-x [fl]] [-Z [Z]] [--] [names]
Use the ``-h'' option to get more help information.
[root@slicer ~]# rmmod hpsa
ERROR: Module hpsa is in use
[root@slicer ~]#
Hmm, that's not cool.
Steve,
That 'sleep 10 < /dev/sg1' worries me. The purpose of a
read() on a sg device is to fetch the response of a SCSI
command sent by a preceding write(). So with nothing to
read and a blocking sg device file descriptor the read()
probably hangs. IMO the valid use of the sg driver should
not have a read() hanging for a SCSI command that was
never sent. While that is happening you remove the
device.
That may be a valid torture test for the sg driver but
isn't something that should be encouraged from the
user space.
On a Ubuntu kernel 2.6.31-17-generic using a virtual
device owned by the scsi_debug driver and the same
torture test, I don't have a problem with 'rmmod scsi_debug'
IMO the usb-storage driver is not a good yardstick.
Doug Gilbert
Maybe it's my driver. Let me try with USB.
[root@slicer ~]# cat /proc/scsi/scsi
Attached devices:
Host: scsi1 Channel: 00 Id: 00 Lun: 00
Vendor: USB Model: DISK 2.0 Rev: 0403
Type: Direct-Access ANSI SCSI revision: 00
[root@slicer ~]# lsmod | grep sd
sd_mod 59592 0
scsi_mod 189304 9 usb_storage,ib_iser,iscsi_tcp,libiscsi,scsi_transport_iscsi,scsi_dh,sg,cciss,sd_mod
[root@slicer ~]# rmmod usb_storage
[root@slicer ~]# cat /proc/scsi/scsi
Attached devices:
[root@slicer ~]# modprobe usb_storage
[root@slicer ~]# cat /proc/scsi/scsi
Attached devices:
[root@slicer ~]# echo scsi add-single-device 1 0 0 0 > /proc/scsi/scsi
-bash: echo: write error: No such device or address
Oh yeah, the host number increments, forgot about that...
[root@slicer ~]# echo scsi add-single-device 2 0 0 0 > /proc/scsi/scsi
[root@slicer ~]# cat /proc/scsi/scsi
Attached devices:
Host: scsi2 Channel: 00 Id: 00 Lun: 00
Vendor: USB Model: DISK 2.0 Rev: 0403
Type: Direct-Access ANSI SCSI revision: 00
[root@slicer ~]# lsscsi -g
[2:0:0:0] disk USB DISK 2.0 0403 /dev/sda /dev/sg0
[root@slicer ~]# sleep 10 < /dev/sg0 & ( sleep 1 && echo scsi remove-single-device 2 0 0 0 > /proc/scsi/scsi )
[1] 6073
[root@slicer ~]#
[root@slicer ~]#
[1]+ Done sleep 10 < /dev/sg0
[root@slicer ~]# rmmod usb_storage
ERROR: Module usb_storage is in use
[root@slicer ~]#
Hmm, same thing.
Any thoughts? (other than "don't do that." Our array configuration
utility for smart arrays is causing similar trouble, as it rapidly creates
and deletes logical drives, etc. so it would be nice if this didn't happen.)
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
