From: Dave Chinner <david@fromorbit.com>
To: Phil White <pwhite@sgi.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 13/25] xfs: factor dir2 block read operations
Date: Wed, 31 Oct 2012 09:16:11 +1100 [thread overview]
Message-ID: <20121030221611.GC29378@dastard> (raw)
In-Reply-To: <20121030032309.GP30227@caliban.engr.sgi.com>
On Mon, Oct 29, 2012 at 08:23:09PM -0700, Phil White wrote:
> On Thu, Oct 25, 2012 at 05:34:02PM +1100, Dave Chinner wrote:
> > +static void
> > +xfs_dir2_block_need_space(
> > ...
> > + /*
> > + * If there are stale entries we'll use one for the leaf.
> > + */
> > + if (btp->stale) {
> > + if (be16_to_cpu(bf[0].length) >= len) {
> > + /*
> > + * The biggest entry enough to avoid compaction.
> > + */
> > + dup = (xfs_dir2_data_unused_t *)
> > + ((char *)hdr + be16_to_cpu(bf[0].offset));
> > + goto out;
> > + }
> > +
> > + /*
> > + * Will need to compact to make this work.
> > + * Tag just before the first leaf entry.
> > + */
> > + *compact = 1;
> > + tagp = (__be16 *)blp - 1;
> > +
> > + /* Data object just before the first leaf entry. */
> > + dup = (xfs_dir2_data_unused_t *)((char *)hdr + be16_to_cpu(*tagp));
> > +
> > + /*
> > + * If it's not free then the data will go where the
> > + * leaf data starts now, if it works at all.
> > + */
> > + if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
> > + if (be16_to_cpu(dup->length) + (be32_to_cpu(btp->stale) - 1) *
> > + (uint)sizeof(*blp) < len)
> > + dup = NULL;
> > + } else if ((be32_to_cpu(btp->stale) - 1) * (uint)sizeof(*blp) < len)
> > + dup = NULL;
> > + else
> > + dup = (xfs_dir2_data_unused_t *)blp;
> > + goto out;
> > + }
> > +
> > + /*
> > + * no stale entries, so just use free space.
> > + * Tag just before the first leaf entry.
> > + */
> > + tagp = (__be16 *)blp - 1;
>
> Shouldn't tagp just be set before this if statement rather than inside of it
> and outside of it?
No, because there is a case where it isn't set.
In general, when factoring code it's not a good idea to change logic
because that's where bugs most commonly creep in. At some point in
the future this could probably do with a more robust cleanup (rather
than just factoring), but right now that's out-of-scope for what I'm
doing...
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
next prev parent reply other threads:[~2012-10-30 22:14 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-25 6:33 [PATCH 00/25, V3] xfs: metadata buffer verifiers Dave Chinner
2012-10-25 6:33 ` [PATCH 01/25] xfs: growfs: don't read garbage for new secondary superblocks Dave Chinner
2012-10-30 0:17 ` Phil White
2012-10-25 6:33 ` [PATCH 02/25] xfs: invalidate allocbt blocks moved to the free list Dave Chinner
2012-10-26 8:47 ` Christoph Hellwig
2012-10-30 0:22 ` Phil White
2012-10-25 6:33 ` [PATCH 03/25] xfs: make buffer read verication an IO completion function Dave Chinner
2012-10-30 0:29 ` Phil White
2012-10-30 0:45 ` Dave Chinner
2012-10-30 0:55 ` Phil White
2012-10-25 6:33 ` [PATCH 04/25] xfs: uncached buffer reads need to return an error Dave Chinner
2012-10-26 8:48 ` Christoph Hellwig
2012-10-30 0:36 ` Phil White
2012-10-25 6:33 ` [PATCH 05/25] xfs: verify superblocks as they are read from disk Dave Chinner
2012-10-30 0:48 ` Phil White
2012-10-25 6:33 ` [PATCH 06/25] xfs: verify AGF blocks " Dave Chinner
2012-10-30 0:51 ` Phil White
2012-10-25 6:33 ` [PATCH 07/25] xfs: verify AGI " Dave Chinner
2012-10-30 0:53 ` Phil White
2012-10-30 22:13 ` Dave Chinner
2012-10-25 6:33 ` [PATCH 08/25] xfs: verify AGFL " Dave Chinner
2012-10-30 1:00 ` Phil White
2012-10-25 6:33 ` [PATCH 09/25] xfs: verify inode buffers " Dave Chinner
2012-10-30 1:06 ` Phil White
2012-10-25 6:33 ` [PATCH 10/25] xfs: verify btree blocks " Dave Chinner
2012-10-30 1:14 ` Phil White
2012-10-25 6:34 ` [PATCH 11/25] xfs: verify dquot " Dave Chinner
2012-10-30 1:36 ` Phil White
2012-10-25 6:34 ` [PATCH 12/25] xfs: add verifier callback to directory read code Dave Chinner
2012-10-30 3:15 ` Phil White
2012-10-25 6:34 ` [PATCH 13/25] xfs: factor dir2 block read operations Dave Chinner
2012-10-30 3:23 ` Phil White
2012-10-30 22:16 ` Dave Chinner [this message]
2012-10-25 6:34 ` [PATCH 14/25] xfs: verify dir2 block format buffers Dave Chinner
2012-10-30 3:26 ` Phil White
2012-10-25 6:34 ` [PATCH 15/25] xfs: factor dir2 free block reading Dave Chinner
2012-10-30 13:14 ` Phil White
2012-10-25 6:34 ` [PATCH 16/25] xfs: factor out dir2 data " Dave Chinner
2012-10-30 13:21 ` Phil White
2012-10-25 6:34 ` [PATCH 17/25] xfs: factor dir2 leaf read Dave Chinner
2012-10-30 13:22 ` Phil White
2012-10-25 6:34 ` [PATCH 18/25] xfs: factor and verify attr leaf reads Dave Chinner
2012-10-30 13:26 ` Phil White
2012-10-25 6:34 ` [PATCH 19/25] xfs: add xfs_da_node verification Dave Chinner
2012-10-30 13:30 ` Phil White
2012-10-30 22:23 ` Dave Chinner
2012-10-31 0:23 ` Phil White
2012-10-31 0:50 ` Dave Chinner
2012-10-25 6:34 ` [PATCH 20/25] xfs: Add verifiers to dir2 data readahead Dave Chinner
2012-10-30 13:31 ` Phil White
2012-10-25 6:34 ` [PATCH 21/25] xfs: add buffer pre-write callback Dave Chinner
2012-10-26 8:50 ` Christoph Hellwig
2012-10-30 22:30 ` Dave Chinner
2012-10-31 10:20 ` Christoph Hellwig
2012-10-30 13:32 ` Phil White
2012-10-25 6:34 ` [PATCH 22/25] xfs: add pre-write metadata buffer verifier callbacks Dave Chinner
2012-10-30 13:34 ` Phil White
2012-10-25 6:34 ` [PATCH 23/25] xfs: connect up write verifiers to new buffers Dave Chinner
2012-10-30 13:39 ` Phil White
2012-10-30 22:34 ` Dave Chinner
2012-10-25 6:34 ` [PATCH 24/25] xfs: convert buffer verifiers to an ops structure Dave Chinner
2012-10-30 13:41 ` Phil White
2012-10-25 6:34 ` [PATCH 25/25] xfs: add write verifiers to log recovery Dave Chinner
2012-10-26 8:54 ` Christoph Hellwig
2012-10-26 20:31 ` Dave Chinner
2012-10-30 12:23 ` Christoph Hellwig
2012-10-30 22:08 ` Dave Chinner
2012-10-31 10:19 ` Christoph Hellwig
2012-10-30 13:44 ` Phil White
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20121030221611.GC29378@dastard \
--to=david@fromorbit.com \
--cc=pwhite@sgi.com \
--cc=xfs@oss.sgi.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.