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 q736BsLc044875 for ; Fri, 3 Aug 2012 01:11:54 -0500 Received: from rcsinet15.oracle.com (rcsinet15.oracle.com [148.87.113.117]) by cuda.sgi.com with ESMTP id IkEXYYExZgX365OD (version=TLSv1 cipher=AES256-SHA bits=256 verify=NO) for ; Thu, 02 Aug 2012 23:11:53 -0700 (PDT) Received: from acsinet22.oracle.com (acsinet22.oracle.com [141.146.126.238]) by rcsinet15.oracle.com (Sentrion-MTA-4.2.2/Sentrion-MTA-4.2.2) with ESMTP id q736BpUo006473 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 3 Aug 2012 06:11:51 GMT Received: from acsmt358.oracle.com (acsmt358.oracle.com [141.146.40.158]) by acsinet22.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id q736BoXp012515 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Fri, 3 Aug 2012 06:11:51 GMT Received: from abhmt105.oracle.com (abhmt105.oracle.com [141.146.116.57]) by acsmt358.oracle.com (8.12.11.20060308/8.12.11) with ESMTP id q736BofX024256 for ; Fri, 3 Aug 2012 01:11:50 -0500 Message-ID: <501B6B7B.5040602@oracle.com> Date: Fri, 03 Aug 2012 14:11:07 +0800 From: Jeff Liu MIME-Version: 1.0 Subject: [PATCH v6 3/4] xfs: xfs_seek_data() refinement with lookup data buffer 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 Refine xfs_seek_data() to check up data buffer offset from page cache for unwritten extents. Signed-off-by: Jie Liu --- fs/xfs/xfs_file.c | 77 ++++++++++++++++++++++++++++++++++++++++------------ 1 files changed, 59 insertions(+), 18 deletions(-) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index aff0c30..e852e52 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1187,8 +1187,6 @@ xfs_seek_data( struct inode *inode = file->f_mapping->host; struct xfs_inode *ip = XFS_I(inode); struct xfs_mount *mp = ip->i_mount; - struct xfs_bmbt_irec map[2]; - int nmap = 2; loff_t uninitialized_var(offset); xfs_fsize_t isize; xfs_fileoff_t fsbno; @@ -1204,34 +1202,77 @@ xfs_seek_data( goto out_unlock; } - fsbno = XFS_B_TO_FSBT(mp, start); - /* * Try to read extents from the first block indicated * by fsbno to the end block of the file. */ + fsbno = XFS_B_TO_FSBT(mp, start); 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; + error = xfs_bmapi_read(ip, fsbno, end - fsbno, map, &nmap, + XFS_BMAPI_ENTIRE); + if (error) + goto out_unlock; - /* - * Treat unwritten extent as data extent since it might - * contains dirty data in page cache. - */ - if (map[0].br_startblock != HOLESTARTBLOCK) { - offset = max_t(loff_t, start, - XFS_FSB_TO_B(mp, map[0].br_startoff)); - } else { + /* No extents at given offset, must be beyond EOF */ + if (nmap == 0) { + error = ENXIO; + goto out_unlock; + } + + offset = start; + /* Landed in a data extent */ + if (map[0].br_startblock == DELAYSTARTBLOCK || + (map[0].br_state == XFS_EXT_NORM && + !isnullstartblock(map[0].br_startblock))) + break; + + /* + * Landed in an unwritten extent, try to search data + * from page cache. + */ + if (map[0].br_state == XFS_EXT_UNWRITTEN) { + if (xfs_find_get_desired_pgoff(inode, &map[0], + DATA_OFF, &offset)) + break; + } + + /* + * 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)); + /* We have two mappings, proceed to check map[1] */ + offset = XFS_FSB_TO_B(mp, map[1].br_startoff); + if (map[1].br_startblock == DELAYSTARTBLOCK || + (map[1].br_state == XFS_EXT_NORM && + !isnullstartblock(map[1].br_startblock))) + break; + + if (map[1].br_state == XFS_EXT_UNWRITTEN) { + if (xfs_find_get_desired_pgoff(inode, &map[1], + DATA_OFF, &offset)) + break; + } + + /* + * Nothing was found, proceed to the next round of search + * if reading offset not beyond or hit EOF. + */ + fsbno = map[1].br_startoff + map[1].br_blockcount; + start = XFS_FSB_TO_B(mp, fsbno); + if (start >= isize) { + error = ENXIO; + goto out_unlock; + } } if (offset != file->f_pos) -- 1.7.4.1 _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs