On Fri, Nov 23, 2012 at 03:34:03AM -0500, Christoph Hellwig wrote:
> On Fri, Nov 23, 2012 at 02:24:25PM +1100, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@xxxxxxxxxx>
> >
> > XFS_IOC_ZERO_RANGE simply does not work properly for non page cache
> > aligned ranges. Neither test 242 or 290 exercise this correctly, so
> > the behaviour is completely busted even though the tests pass.
> >
> > Fix it to support full byte range granularity as was originally
> > intended for this ioctl.
>
> Looks good, but a couple cosmetic comments below:
>
> > + rounding = max_t(uint, 1 << mp->m_sb.sb_blocklog, PAGE_CACHE_SIZE);
>
> I'd call this granularity.
OK. I just copied that from the hole punch code. ;)
> > + /* round the range iof extents we are going to convert inwards */
> > + start = round_up(offset, rounding);
> > + end = round_down(offset + len, rounding);
>
> start_boundary, end_boundary?
OK.
> > + if (start < end - 1) {
> > + /* punch out the page cache over the conversion range */
> > + truncate_pagecache_range(VFS_I(ip), start, end - 1);
> > + /* convert the blocks */
> > + error = xfs_alloc_file_space(ip, start, end - start - 1,
> > + XFS_BMAPI_PREALLOC | XFS_BMAPI_CONVERT,
> > + attr_flags);
> > + if (error)
> > + goto out_unlock;
> > + } else {
> > + /* it's a sub-rounding range */
> > + ASSERT(offset + len <= start);
> > + error = xfs_iozero(ip, offset, len);
> > + goto out_unlock;
> > + }
> > +
> > + /* now we've handled the interior of the range, handle the edges */
> > + if (start != offset)
> > + error = xfs_iozero(ip, offset, start - offset);
> > + if (!error && end != offset + len)
> > + error = xfs_iozero(ip, end, offset + len - end);
>
> I'd move the edge iozero calls into the if branch, that gives a natural
> code flow and avoids the goto unlock in the sub-page case.
Sure. I added the sub-page case after the edge cases when I realised
the edge cases didn't handle that. I'll rework it.
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
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