Hi Vladimir,
Thank you again for replies.
--- "Vladimir V. Saveliev" <[EMAIL PROTECTED]> wrote:
> reiserfs has to replay journal before it can access
> any data. Even if it is
> mounting readonly. Journal replay code does not
> distinguish whether filesystem
> is being mounted read-only or not. So, it just
> replays journal and updates few
> counters. If filesystem was umounted clean - no
> transactions are replayed, but
> counters still get updated.
Thank you for informational reply here. This makes
sense, and we will note the reply, but in some
industry mounting read-only means truly read only with
nothing changed. Computer forensics, one example. If
we want to preview the file system before we acquire
we must mount read-only. But journal increment
changes data, minimal as it is, the authentication no
longer matches and opposing counsel swoop in like
vultures.
> > and ultimately C) is there something
> > else besides changing source code to stop this?
> >
> Please send your patch so that we could see first
> what you have done already.
>
What we have done is change two lines in kernel
source, fs/reiserfs/journal.c from;
SB_JOURNAL(p_s_sb)->j_mount_id =
le32_to_cpu(jh->j_mount_id) + 1;
} else {
SB_JOURNAL(p_s_sb)->j_mount_id = newest_mount_id + 1
;
to;
SB_JOURNAL(p_s_sb)->j_mount_id =
le32_to_cpu(jh->j_mount_id) + 0;
} else {
SB_JOURNAL(p_s_sb)->j_mount_id = newest_mount_id + 0
;
This has work for us - when we mount using this kernel
ReiserFS file systems do not change - the
authentication pre and post are equivalent.
We would never mount a ReiserFS file system we wish to
write to with this kernel, only those we preview.
It would be nice to have a mount option that would not
increment journal count instead of going this kernel
route.
kind regards,
-lt
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