From: Brian Foster <bfoster@redhat.com>
To: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com
Subject: Re: [RFC PATCH 2/2] xfs: sysfs attributes for the current log state
Date: Tue, 20 May 2014 07:17:06 -0400 [thread overview]
Message-ID: <20140520111706.GA3124@laptop.bfoster> (raw)
In-Reply-To: <20140519215658.GD8554@dastard>
On Tue, May 20, 2014 at 07:56:58AM +1000, Dave Chinner wrote:
> On Fri, May 16, 2014 at 02:12:46PM -0400, Brian Foster wrote:
> > Create sysfs attributes to export the current runtime state of the log
> > to userspace. Note that the filesystem should be frozen for best
> > accuracy/consistency when reading these values, but is not required.
> > This is for testing and debug purposes only.
> >
> > Create the following per-mount attributes: log_head_lsn, log_tail_lsn,
> > reserve_head_lsn and write_head_lsn. These represent the physical log
>
> Reserve and write heads are not log sequence numbers (LSNs). A LSN
> is a cycle:block count tuple, while a grant head is a cycle:byte
> count tuple....
>
Yeah, I suppose that's some terminology abuse... ;)
> Calling the reserve_grant_head/write_grant_head would make more
> sense, I think, as would splitting them into cycle/byte output
> pairs. Splitting them make sense because if we increase the log size
> beyond 2GB we're going to need a different in-memory representation
> for the grant heads (i.e. need more than 32 bits for byte count), so
> we should probably handle that up front in the sysfs API...
>
Ok. reserve_grant_head and write_grant_head in the decimal format of
"cycle:bytes" it is. I'll leave the names of the others and convert them
to a similar "cycle:blocks" format. Thanks!
Brian
> Cheers,
>
> Dave.
> --
> Dave Chinner
> david@fromorbit.com
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next prev parent reply other threads:[~2014-05-20 11:22 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-16 18:12 [RFC PATCH 0/2] xfs: sysfs attribute support Brian Foster
2014-05-16 18:12 ` [RFC PATCH 1/2] xfs: add basic per-mount " Brian Foster
2014-05-20 12:16 ` Dave Chinner
2014-05-16 18:12 ` [RFC PATCH 2/2] xfs: sysfs attributes for the current log state Brian Foster
2014-05-19 21:56 ` Dave Chinner
2014-05-20 11:17 ` Brian Foster [this message]
2014-05-20 11:52 ` Dave Chinner
2014-05-21 14:48 ` [RFC PATCH 0/2] xfs: sysfs attribute support Christoph Hellwig
2014-05-22 13:16 ` Brian Foster
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