From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id q6V88jiI159295 for ; Tue, 31 Jul 2012 03:08:45 -0500 Received: from acsinet15.oracle.com (acsinet15.oracle.com [141.146.126.227]) by cuda.sgi.com with ESMTP id A87uSR5vGF6EPJBI (version=TLSv1 cipher=AES256-SHA bits=256 verify=NO) for ; Tue, 31 Jul 2012 01:08:44 -0700 (PDT) Message-ID: <50179282.9000300@oracle.com> Date: Tue, 31 Jul 2012 16:08:34 +0800 From: Jie Liu MIME-Version: 1.0 Subject: Re: [PATCH v5 4/4]xfs: xfs_seek_hole() refinements with lookup hole offset from page cache. References: <50110636.2010602@oracle.com> <20120731001322.GN2877@dastard> In-Reply-To: <20120731001322.GN2877@dastard> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============7782120384210952446==" Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Dave Chinner Cc: xfs@oss.sgi.com This is a multi-part message in MIME format. --===============7782120384210952446== Content-Type: multipart/alternative; boundary="------------060608010604070609050903" This is a multi-part message in MIME format. --------------060608010604070609050903 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit On 07/31/12 08:13, Dave Chinner wrote: > On Thu, Jul 26, 2012 at 04:56:22PM +0800, Jeff Liu wrote: >> Search possbile hole offset for given range from page cache for unwritten and delayed-allocation extents. >> >> Signed-off-by: Jie Liu >> Reviewed-by: Mark Tinguely >> Reviewed-by: Christoph Hellwig >> Reviewed-by: Dave Chinner >> >> --- >> 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. >> + */ > Laned in a data extent is more correct here. > >> + 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; >> + } > 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 { > ..... > >> /* >> - * 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; >> + } > And that check can move to the start of the loop, too. Thanks for a comprehensive review, I'll fix them according to your comments. Thanks, -Jeff // > > Cheers, > > Dave. --------------060608010604070609050903 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit
On 07/31/12 08:13, Dave Chinner wrote:
On Thu, Jul 26, 2012 at 04:56:22PM +0800, Jeff Liu wrote:

Search possbile hole offset for given range from page cache for unwritten and delayed-allocation extents.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

---
 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.
+			 */

Laned in a data extent is more correct here.


+			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;
+			}

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 {
			.....


 		/*
-		 * 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;
+		}

And that check can move to the start of the loop, too.
Thanks for a comprehensive review, I'll fix them according to your comments.

Thanks,
-Jeff

Cheers,

Dave.

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