Re: Corrupted/unreadable journal: reiser vs. ext3

[Oleg Drokin <green@namesys.com>]

Hello!

On Sat, Feb 15, 2003 at 02:04:54PM +0100, Anders Widman wrote:
> > Ok, so probably we should make the following changes. The kernel set IO_ERROR
> > and FS_ERROR flags. 
> > In the case of IO_ERROR reiserfsck prints the message about hardware problems
> > and returns error, so the fs does not get mounted at boot. On attempt mounting
> > the fs with IO_ERROR flag set it is mounted ro with some message about hardware
> > problems. When you are sure that problems disappeared you can mount it with a
> > spetial option cleaning this flag and probably reiserfstune will have some
> > option cleaning these flags also.
> > In the case of FS_ERROR - search_by_key failed or beyond end of device access
> > or similar - reiserfsck gets -a option at boot, replays the journal if needed
> > and checks for the flag. No flag - returns OK. Else - run fix-fixable. Errors
> > left - returns 'errors left uncorrected' and the fs does not get mounted at
> > boot. On attempt mounting the fs with the flag just print the message about
> > mounting the fs with errors and mount it. Not ro here as kernel will not do
> > deep analysis of errors and it could be just a small insignificant error.
>   What  happens if there are FS errors on boot device? Not mounting ro

It get's mounted readonly first, then fsck will exit with appropriate error code,
then system will refuse to continue booting process, I presume ;)

>   will  make  system  inaccessible unless users has some other boot or
>   rescue media.

Sure, just like with any other filesystem.
If you want to avoid that, don't run fsck on your root device during boot,
or ignore what it have said to you ;)

>   Of  course, this  is  where  admins  should  have  another  disk  or
>   partition to boot and make FS repairs. :)

Actually it is possible to reiserfsck (readonly) mounted filesystem. The only
prerequisite I found is reiserfsck binary (built statically it seems, or
with all the libs) should be located on another fs (tmpfs works just fine for me).
And of course little bit of reiserfsck patching is needed ;)
That's how I repair broken root filesystems on our test-boxes when rootfs is getting
corrupt, because some moron\bclear guy have not created rescue partition in there
and I hate booting from CDs (And CDs usually have outdated reiserfsck anyway). 

Bye,
    Oleg