Re: scsi_wait_scan not working (2.6.30.5)

[Arkadiusz Miskiewicz <a.miskiewicz@gmail.com>]

On Tuesday 25 of August 2009, Arkadiusz Miskiewicz wrote:
> On Tuesday 25 of August 2009, you wrote:
> > On Tue, 2009-08-25 at 21:44 +0200, Arkadiusz Miskiewicz wrote:
> > > On Tuesday 25 of August 2009, James Bottomley wrote:
> > > > On Tue, 2009-08-25 at 21:24 +0200, Arkadiusz Miskiewicz wrote:
> > > > > What could be the reason for scsi_wait_scan not waiting untill all
> > > > > disks are found?
> > > > >
> > > > > I'm testing 2.6.30.5 on hardware with LSI Logic / Symbios Logic
> > > > > MegaRAID 530 SCSI 320-0X RAID controller and modprobe
> > > > > scsi_wait_scan finishes earlier than disks are found.
> > > > >
> > > > > My initrd (romfs) does:
> > > > > insmod /lib/modules/2.6.30.5-0.3/kernel/drivers/scsi/scsi_mod.ko
> > > > > insmod
> > > > > /lib/modules/2.6.30.5-0.3/kernel/drivers/scsi/megaraid/megaraid_mm.
> > > > >ko insmod
> > > > > /lib/modules/2.6.30.5-0.3/kernel/drivers/scsi/megaraid/megaraid_mbo
> > > > >x. ko insmod /lib/modules/2.6.30.5-0.3/kernel/lib/crc-t10dif.ko
> > > > > insmod /lib/modules/2.6.30.5-0.3/kernel/drivers/scsi/sd_mod.ko
> > > > > insmod
> > > > > /lib/modules/2.6.30.5-0.3/kernel/drivers/scsi/scsi_wait_scan.ko
> > > > > insmod /lib/modules/2.6.30.5-0.3/kernel/fs/exportfs/exportfs.ko
> > > > > insmod /lib/modules/2.6.30.5-0.3/kernel/fs/xfs/xfs.ko
> > > > > if [ "${ROOT##/dev/}" != "${ROOT}" ]; then
> > > > > rootnr="$(busybox awk -v rootnode="${ROOT##/dev/}" '$4 == rootnode
> > > > > { print 256 * $1 + $2 }' /proc/partitions)"
> > > > > if [ -n "$rootnr" ]; then
> > > > > echo "$rootnr" > /proc/sys/kernel/real-root-dev
> > > > > fi
> > > > >
> > > > >
> > > > > Now if I add sleep few seconds or /bin/sh at the end of this
> > > > > initrd, then boot and then disks are detected properly and rootfs
> > > > > is mounted properly (after I exit from sh in case when /bin/sh is
> > > > > used).
> > > > >
> > > > > The question remains - why scsi_wait_scan doesn't wait?
> > > >
> > > > It's caused by the sd async patches.  What's happening is wait_scan
> > > > is waiting until all the scans are complete, but now sd attachment
> > > > may not be completed by the time that happens.  So, although you have
> > > > a scanned disk, you can't mount it without and attached sd driver.
> > > >
> > > > Hopefully when
> > > > all initrds are configured to wait until root appears, this problem
> > > > will go away.
> > >
> > > Uh, ugly. I'll disable SCSI_SCAN_ASYNC here then.
> >
> > That won't actually help: the sd async scan is a separate mechanism not
> > tied to that variable
>
> I assume there is no configurable way to disable this?

I found this patch

http://marc.info/?l=linux-scsi&m=124388639906873&w=2

but it doesn't work on 30.5 (it's still not waiting untill everything is 
discovered)


-- 
Arkadiusz Miśkiewicz        PLD/Linux Team
arekm / maven.pl            http://ftp.pld-linux.org/
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