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
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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
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