lkml.org 
[lkml]   [2001]   [May]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: Why side-effects on open(2) are evil. (was Re: [RFD w/info-PATCH]device arguments from lookup)
Date
On Tuesday 22 May 2001 22:10, Andreas Dilger wrote:
> Peter Braam writes:
> > File system journal recovery can corrupt a snapshot, because it
> > copies data that needs to be preserved in a snapshot. During
> > journal replay such data may be copied again, but the source can
> > have new data already.
>
> The way it is implemented in reiserfs is to wait for existing
> transactions to complete, entirely flush the journal and block all
> new transactions from starting. Stephen implemented a journal flush
> API to do this for ext3, but the hooks to call it from LVM are not in
> place yet. This way the journal is totally empty at the time the
> snapshot is done, so the read-only copy does not need to do journal
> recovery, so no problems can arise.

I suppose I'm just reiterating the obvious, but we should eventually
have a generic filesystem transaction API at the VFS level, once we
have enough data points to know what the One True API should be.

--
Daniel
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 12:53    [W:0.139 / U:4.400 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site