From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id q6Q8v5CJ003410 for ; Thu, 26 Jul 2012 03:57:05 -0500 Received: from acsinet15.oracle.com (acsinet15.oracle.com [141.146.126.227]) by cuda.sgi.com with ESMTP id ZtQuY9bQzp6vl4km (version=TLSv1 cipher=AES256-SHA bits=256 verify=NO) for ; Thu, 26 Jul 2012 01:57:04 -0700 (PDT) Received: from acsinet21.oracle.com (acsinet21.oracle.com [141.146.126.237]) by acsinet15.oracle.com (Sentrion-MTA-4.2.2/Sentrion-MTA-4.2.2) with ESMTP id q6Q8v2uH016763 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 26 Jul 2012 08:57:02 GMT Received: from acsmt358.oracle.com (acsmt358.oracle.com [141.146.40.158]) by acsinet21.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id q6Q8v1Yn012665 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 26 Jul 2012 08:57:02 GMT Received: from abhmt106.oracle.com (abhmt106.oracle.com [141.146.116.58]) by acsmt358.oracle.com (8.12.11.20060308/8.12.11) with ESMTP id q6Q8v1oT022254 for ; Thu, 26 Jul 2012 03:57:01 -0500 Message-ID: <50110636.2010602@oracle.com> Date: Thu, 26 Jul 2012 16:56:22 +0800 From: Jeff Liu MIME-Version: 1.0 Subject: [PATCH v5 4/4]xfs: xfs_seek_hole() refinements with lookup hole offset from page cache. Reply-To: jeff.liu@oracle.com List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: xfs@oss.sgi.com 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. + */ + 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; + } + + /* + * map[0] is unwritten and there is no hole past + * offset, probably means that we are reading after + * EOF. Hence, we should fix offset to point to the + * end of the file(i.e., there is an implicit hole at + * the end of any file). + */ + if (nmap == 1) { + offset = isize; + break; + } + + /* We have two mappings, proceed to check map[1] */ + offset = XFS_FSB_TO_B(mp, map[1].br_startoff); + if (map[1].br_startblock == HOLESTARTBLOCK) + break; + else { + /* + * map[1] is also an unwritten extent, try + * to lookup hole from the page cache again. + */ + if (map[1].br_state == XFS_EXT_UNWRITTEN || + isnullstartblock(map[1].br_startblock)) { + if (xfs_find_get_desired_pgoff(inode, + &map[1], HOLE_OFF, &offset)) + break; + } + } + } + /* - * 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; + } } + + /* + * Come to here, we must have found a hole. However, the returned + * offset might be greater than the file size as it might be fixed + * to block buffer unit boundary at page cache lookup procedure for + * unwritten and delayed-allocation extents, we need to deal with + * this situation in particular. + */ + offset = min_t(loff_t, offset, isize); if (offset != file->f_pos) file->f_pos = offset; -- 1.7.4.1 _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs