Re: [PATCH v7 3/4] xfs: xfs_seek_data() refinement with unwritten extents check up from page cache
From: Dave Chinner <david@fromorbit.com>
Date: 2012-08-20 23:16:10
On Mon, Aug 13, 2012 at 09:08:09PM +0800, Jeff Liu wrote:
Improve xfs_seek_data() to search data offset from page cache for unwritten extents. Signed-off-by: Jie Liu <redacted>
One minor addition, otherwise Reviewed-by: Dave Chinner <redacted> ....
+
+ /*
+ * map[0] is hole or its an unwritten extent but
+ * without data in page cache. Probably means that
+ * we are reading after EOF if nothing in map[1].
+ */
if (nmap == 1) {
error = ENXIO;
goto out_unlock;
}
- offset = max_t(loff_t, start,
- XFS_FSB_TO_B(mp, map[1].br_startoff));
+ /*
+ * Nothing was found, proceed to the next round of search
+ * if reading offset not beyond or hit EOF.
+ */ASSERT(i > 1);
+ fsbno = map[i - 1].br_startoff + map[i - 1].br_blockcount;
+ start = XFS_FSB_TO_B(mp, fsbno);
+ if (start >= isize) {
+ error = ENXIO;
+ goto out_unlock;
+ }
}
+out:
if (offset != file->f_pos)
file->f_pos = offset;Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs