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 q7L9D1DQ060247 for ; Tue, 21 Aug 2012 04:13:01 -0500 Received: from rcsinet15.oracle.com (rcsinet15.oracle.com [148.87.113.117]) by cuda.sgi.com with ESMTP id 1SobmI1G7AA6NAKd (version=TLSv1 cipher=AES256-SHA bits=256 verify=NO) for ; Tue, 21 Aug 2012 02:13:00 -0700 (PDT) Received: from acsinet21.oracle.com (acsinet21.oracle.com [141.146.126.237]) by rcsinet15.oracle.com (Sentrion-MTA-4.2.2/Sentrion-MTA-4.2.2) with ESMTP id q7L9CwY2023031 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 21 Aug 2012 09:12:59 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 q7L9Cw9N002797 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Tue, 21 Aug 2012 09:12:58 GMT Received: from abhmt120.oracle.com (abhmt120.oracle.com [141.146.116.72]) by acsmt358.oracle.com (8.12.11.20060308/8.12.11) with ESMTP id q7L9CwdH018402 for ; Tue, 21 Aug 2012 04:12:58 -0500 Message-ID: <503350E7.2050109@oracle.com> Date: Tue, 21 Aug 2012 17:12:07 +0800 From: Jeff Liu MIME-Version: 1.0 Subject: [PATCH v8 3/4] xfs: xfs_seek_data() refinement with unwritten extents check up 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 xfs_seek_data() refinement with unwritten extents check up from page cache. Signed-off-by: Jie Liu Reviewed-by: Mark Tinguely Reviewed-by: Dave Chinner --- fs/xfs/xfs_file.c | 72 +++++++++++++++++++++++++++++++++++++++------------- 1 files changed, 54 insertions(+), 18 deletions(-) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index d78a746..3f91074 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1186,8 +1186,6 @@ 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; @@ -1203,36 +1201,74 @@ 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; + unsigned int i; - 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; + } + + for (i = 0; i < nmap; i++) { + offset = max_t(loff_t, start, + XFS_FSB_TO_B(mp, map[i].br_startoff)); + + /* Landed in a data extent */ + if (map[i].br_startblock == DELAYSTARTBLOCK || + (map[i].br_state == XFS_EXT_NORM && + !isnullstartblock(map[i].br_startblock))) + goto out; + + /* + * Landed in an unwritten extent, try to search data + * from page cache. + */ + if (map[i].br_state == XFS_EXT_UNWRITTEN) { + if (xfs_find_get_desired_pgoff(inode, &map[i], + DATA_OFF, &offset)) + goto out; + } + } + + /* + * 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)); + ASSERT(i > 1); + + /* + * Nothing was found, proceed to the next round of search + * if reading offset not beyond or hit EOF. + */ + 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; -- 1.7.4.1 _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs