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_mbox.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.
James
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