From: Kay Sievers <kay.sievers@vrfy.org>
To: linux-hotplug@vger.kernel.org
Subject: Re: udev/modprobe issue
Date: Fri, 30 Sep 2005 17:12:26 +0000 [thread overview]
Message-ID: <20050930171226.GB18039@vrfy.org> (raw)
In-Reply-To: <20050929074140.GD2886@schottelius.org>
On Thu, Sep 29, 2005 at 09:41:40AM +0200, Nico Schottelius wrote:
> Good morning everybody!
>
> I've a small problem with loading the sata_sil module, but it could be a
> general issue: We use this sata-kontroller with sata-harddisks to backup
> our systems. The harddisk is exchanged (while the system is running) every
> day. So we load/unload sata_sil in our backup scripts, so 'hotplugging' is possible.
>
> My problem is, that modprobe returns earlier than the attached device is usable:
>
> ----------------------------------------------------------------------
> srwali01:/# modprobe sata_sil; mount /dev/sda1 /mnt/hdbackup/
> mount: you must specify the filesystem type
> srwali01:/# rmmod sata_sil
> srwali01:/# modprobe sata_sil; ls -l /dev/sda1
> ls: /dev/sda1: No such file or directory
> ----------------------------------------------------------------------
>
> So I have to do
>
> ----------------------------------------------------------------------
> srwali01:/# modprobe sata_sil
> srwali01:/# sleep 2
> srwali01:/# mount /dev/sda1 /mnt/hdbackup
> ----------------------------------------------------------------------
>
> The problem is most likely that udev is too slow or that modprobe does not
> know/wait for udev:
>
> ----------------------------------------------------------------------
> srwali01:/# mount | grep tmpfs | grep -v /dev/shm
> tmpfs on /dev type tmpfs (rw,size\x10M,mode\a55)
> srwali01:/# cat /proc/sys/kernel/hotplug
> /sbin/udevsend
> ----------------------------------------------------------------------
>
> My questions:
>
> - Should modprobe wait for whatever current hotplug is so that
> the system can definitly use the device after modprobe?
No.
> - Or should there be a command-line switch to modprobe to tell it to wait
> for hotplug?
No.
> - Is the 'wait for hotplug'-idea possible to do or would it have to be a dirty
> hack in the kernel?
Not possible.
> - Is there clean solution to wait exactly as long as
> it needs to load sata_sil and create /dev/sda*?
> Using while+ls monitoring /dev/sda* is not a solution imho.
Wait for the node, or use the device event the kernel generates for the device
you're looking for. You can catch it with a udev rule.
Kay
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next prev parent reply other threads:[~2005-09-30 17:12 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-09-29 7:41 udev/modprobe issue Nico Schottelius
2005-09-30 17:12 ` Kay Sievers [this message]
2005-10-02 22:05 ` Nico -telmich- Schottelius
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