Messages in this thread | | | Date | Thu, 13 Dec 2001 09:01:56 -0600 (CST) | From | Jesse Pollard <> | Subject | Re: passing params to boot readonly |
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--------- Received message begins Here ---------
> > On December 12, 2001 21:50, Stewart Allen wrote: > > I'm in a bit of a pickle and need to find a way to pass boot params to a > > reiserfs rootfs to *prevent* it from replaying the journal on single-user > > boot. This may seem like a strange request, but I've got a degraded RAID > > array that I need to poke around in before deciding whether or not to send > > a disk off to a rehab lab. If the replay occurs, it will potentially > > destroy the fs since I'm using a degraded snapshot of the failed disk in > > hopes of reclaiming *some* of my data. The system is running 2.2.x (can't > > remember and can't find out w/out booting). > > > > Do I have a snowball's chance of pulling this off? > > Well, kinda. The only thing that can deter ReiserFS from replaying the > journal is convincing it that the physical media it's on is actually read > only. Some quick less/grep work revealed that there is no option that makes > the SCSI subsystem claim its devices are readonly (although it'd be extremely > useful for situations such as this). > > It'd probably be pretty easy to make a boot disk using a hacked version of > ReiserFS that refuses to replay the journal, by adding a "return 0;" near the > top of journal_read(struct super_block *) in journal.c. However, you might > feel more comfortable sending it off for data recovery than testing kernel > hacks on it ;)
Wouldn't it be better to make a backup (dd copy) of the disk volume to another drive? The raid would not be mounted, so the fs would not be updated.
I would recommend that be done even before sending the disk out.
ALTERNATIVE TO READ-ONLY and this might not be possible.
If the raid is SCSI based, then there is (should be) a read-only switch in the disk configuration. Most disks do not have a jumper there, and since they are usually internal only, the option is not used. Putting the jumper on (or removing one if it is there - depends on the drive) will make the disk read-only.
Even some IDE drives may have this option, though finding documentation on it may be difficult to locate. ------------------------------------------------------------------------- Jesse I Pollard, II Email: pollard@navo.hpc.mil
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