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<div class="moz-cite-prefix">On 07/31/12 08:13, Dave Chinner wrote:<br>
</div>
<blockquote cite="mid:20120731001322.GN2877@dastard" type="cite">
<pre wrap="">On Thu, Jul 26, 2012 at 04:56:22PM +0800, Jeff Liu wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Search possbile hole offset for given range from page cache for unwritten and delayed-allocation extents.
Signed-off-by: Jie Liu <a class="moz-txt-link-rfc2396E" href="mailto:jeff.liu@oracle.com"><jeff.liu@oracle.com></a>
Reviewed-by: Mark Tinguely <a class="moz-txt-link-rfc2396E" href="mailto:tinguely@sgi.com"><tinguely@sgi.com></a>
Reviewed-by: Christoph Hellwig <a class="moz-txt-link-rfc2396E" href="mailto:hch@lst.de"><hch@lst.de></a>
Reviewed-by: Dave Chinner <a class="moz-txt-link-rfc2396E" href="mailto:dchinner@redhat.com"><dchinner@redhat.com></a>
---
fs/xfs/xfs_file.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++------
1 files changed, 80 insertions(+), 10 deletions(-)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 15acd4d..1b83549 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1296,9 +1296,9 @@ xfs_seek_hole(
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
loff_t uninitialized_var(offset);
- loff_t holeoff;
xfs_fsize_t isize;
xfs_fileoff_t fsbno;
+ xfs_filblks_t end;
uint lock;
int error;
@@ -1314,20 +1314,90 @@ xfs_seek_hole(
}
fsbno = XFS_B_TO_FSBT(mp, start);
- error = xfs_bmap_first_unused(NULL, ip, 1, &fsbno, XFS_DATA_FORK);
- if (error)
- goto out_unlock;
+ end = XFS_B_TO_FSB(mp, isize);
+
+ for (;;) {
+ struct xfs_bmbt_irec map[2];
+ int nmap = 2;
+
+ error = xfs_bmapi_read(ip, fsbno, end - fsbno, map, &nmap,
+ XFS_BMAPI_ENTIRE);
+ if (error)
+ goto out_unlock;
+
+ /* No extents at given offset, must be beyond EOF */
+ if (nmap == 0) {
+ error = ENXIO;
+ goto out_unlock;
+ }
- holeoff = XFS_FSB_TO_B(mp, fsbno);
- if (holeoff <= start)
offset = start;
- else {
+ /* Landed in a hole, return */
+ if (map[0].br_startblock == HOLESTARTBLOCK)
+ break;
+ else {
+ /*
+ * Landed in an unwritten extent, try to lookup page
+ * cache to find holes.
+ */
</pre>
</blockquote>
<pre wrap="">
Laned in a data extent is more correct here.
</pre>
<blockquote type="cite">
<pre wrap="">+ if (map[0].br_state == XFS_EXT_UNWRITTEN ||
+ isnullstartblock(map[0].br_startblock)) {
+ /* Probing page cache start from offset */
+ if (xfs_find_get_desired_pgoff(inode, &map[0],
+ HOLE_OFF, &offset))
+ break;
+ }
</pre>
</blockquote>
<pre wrap="">
Same logic changes as previous patch:
if (map[0].br_startblock == HOLESTARTBLOCK)
break;
else if (map[0].br_state == XFS_EXT_UNWRITTEN) {
ASSERT(!isnullstartblock(map[0].br_startblock));
/* Probing page cache start from offset */
if (xfs_find_get_desired_pgoff(inode, &map[0],
HOLE_OFF, &offset))
break;
} else {
.....
</pre>
<blockquote type="cite">
<pre wrap=""> /*
- * xfs_bmap_first_unused() could return a value bigger than
- * isize if there are no more holes past the supplied offset.
+ * Both mappings contains data, proceed to the next round of
+ * search if the current reading offset not beyond or hit EOF.
*/
- offset = min_t(loff_t, holeoff, isize);
+ fsbno = map[1].br_startoff + map[1].br_blockcount;
+ start = XFS_FSB_TO_B(mp, fsbno);
+ if (start >= isize) {
+ offset = isize;
+ break;
+ }
</pre>
</blockquote>
<pre wrap="">
And that check can move to the start of the loop, too.</pre>
</blockquote>
Thanks for a comprehensive review, I'll fix them according to your
comments.<br>
<br>
Thanks,<br>
-Jeff<br>
<span class="st"><em></em></span>
<blockquote cite="mid:20120731001322.GN2877@dastard" type="cite">
<pre wrap="">
Cheers,
Dave.
</pre>
</blockquote>
<br>
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