From mboxrd@z Thu Jan 1 00:00:00 1970 From: "T. Horsnell" Date: Wed, 13 Dec 2006 15:36:30 +0000 Subject: Re: disk/by-label + label-change Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: linux-hotplug@vger.kernel.org Sorry - forgot to CC: the list. >On Tue, 2006-12-12 at 17:51 +0000, T. Horsnell wrote: >> >On 12/12/06, T. Horsnell wrote: >> >> If a disk with a persistence-entry in /dev/disk/by-label >> >> is re-labelled with tune2fs, the by-label entry isnt >> >> updated to match the new label and when the disk is mounted >> >> with a 'mount -L ', >> > >> >You are writing to a raw sector of the disk, no part of the system >> >will notice that you did this and have changed something. You need to >> >tell the kernel to emit an event by doing: >> > echo "add" > /sys/block/sda/uevent >> >and the link will get updated. >>=20 >> OK, thanks. But shouldnt tune2fs do this when it updates the label? >> I guess I should make my own tune2fs script and do it there. > >Right, that shouldn't be part of the tool that writes to the disk, it >can't know if it's safe to update the links. > >> >> the mounted-device shows up as something >> >> like: >> >> >> >> [root@dev1 ~]# mount >> >> /dev/hdb2 on / type ext3 (rw) >> >> proc on /proc type proc (rw) >> >> sysfs on /sys type sysfs (rw) >> >> devpts on /dev/pts type devpts (rw,gid=3D5,modeb0) >> >> tmpfs on /dev/shm type tmpfs (rw) >> >> none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) >> >> sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw) >> >> >>>> /dev/.tmp-8-17 on /test type ext3 (rw) >> >> >> >> Is this as it should be? >> > >> >Looks like you mounted the device with a PROGRAM rule, right? This is >> >definitely not what it "should be". :) >>=20 >> I do no mounting in udev, its all in fstab. I never thought to >> do it in a udev PROGRAM rule... > >But who is using udev's temporary device node for mount then? > /dev/.tmp-8-17 on /test type ext3 (rw) > >That usually only exists during the udev event processing. Hmm. Of course, I cant reproduce this. But would you mind a related question? The reason I'm doing all this stuff is because of an NFS problem associated with moving disks around on the SCSI bus. I have a fileserver which NFS-exports a bunch of filesystems to a compute farm. The compute farm clients mount these with the 'hard' option so that they stall if they try and make NFS requests while the server is offline. >From time-to-time I make changes in the SCSI configuration of the server (like moving a SCSI shelf to a different SCSI adapter). Without udev persistence rules, the /dev/sdN device for the SCSI disks may change as a result of the shuffle, and my farm clients then sometimes mistakenly access the filesystem on the *old* /dev/sdN. There are no NFS errors, just wrong filesystem contents. I cant use the /dev/disk/by-whatever symlinks because they resolve to the changing /dev/sdN So I make persistence rules such that my disks *always* mount on the same /dev/dskN regardless of where they are on the bus, but then NFS complains of a 'stale filehandle' if server filesystems are moved around. This is a bit better than continuing with the wrong data, but it would be best if NFS knew that the disk was the same=20 disk, even tho it was on a different SCSi bus/slot in the server. Should this be possible with persistent device names? Thanks, Terry > >Kay > > ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=3Djoin.php&p=3Dsourceforge&CID=DEVD= EV _______________________________________________ Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net Linux-hotplug-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel