From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id q6Q8uxc4003390 for ; Thu, 26 Jul 2012 03:56:59 -0500 Received: from acsinet15.oracle.com (acsinet15.oracle.com [141.146.126.227]) by cuda.sgi.com with ESMTP id KrMnHx8xk1MdrSRF (version=TLSv1 cipher=AES256-SHA bits=256 verify=NO) for ; Thu, 26 Jul 2012 01:56:58 -0700 (PDT) Received: from ucsinet21.oracle.com (ucsinet21.oracle.com [156.151.31.93]) by acsinet15.oracle.com (Sentrion-MTA-4.2.2/Sentrion-MTA-4.2.2) with ESMTP id q6Q8uuKG016543 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 26 Jul 2012 08:56:57 GMT Received: from acsmt356.oracle.com (acsmt356.oracle.com [141.146.40.156]) by ucsinet21.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id q6Q8utSc009902 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 26 Jul 2012 08:56:55 GMT Received: from abhmt115.oracle.com (abhmt115.oracle.com [141.146.116.67]) by acsmt356.oracle.com (8.12.11.20060308/8.12.11) with ESMTP id q6Q8utDU015888 for ; Thu, 26 Jul 2012 03:56:55 -0500 Message-ID: <50110630.7020902@oracle.com> Date: Thu, 26 Jul 2012 16:56:16 +0800 From: Jeff Liu MIME-Version: 1.0 Subject: [PATCH v5 3/4]xfs: xfs_seek_data() refinements 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 Search data buffer offset for given range from page cache for unwritten extents. Signed-off-by: Jie Liu Reviewed-by: Mark Tinguely Reviewed-by: Christoph Hellwig Reviewed-by: Dave Chinner --- fs/xfs/xfs_file.c | 88 ++++++++++++++++++++++++++++++++++++++++++----------- 1 files changed, 70 insertions(+), 18 deletions(-) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 43f5e61..15acd4d 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1177,8 +1177,6 @@ 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; @@ -1194,34 +1192,88 @@ 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 { - if (nmap == 1) { + /* No extents at given offset, must be beyond EOF */ + if (nmap == 0) { error = ENXIO; goto out_unlock; } offset = max_t(loff_t, start, - XFS_FSB_TO_B(mp, map[1].br_startoff)); + XFS_FSB_TO_B(mp, map[0].br_startoff)); + if (map[0].br_state == XFS_EXT_NORM && + !isnullstartblock(map[0].br_startblock)) + break; + else { + /* + * Landed in an unwritten extent, try to lookup data + * buffer from the page cache before proceeding to + * check the next extent map. It's a hole if nothing + * was found. + */ + if (map[0].br_startblock == DELAYSTARTBLOCK || + map[0].br_state == XFS_EXT_UNWRITTEN) { + /* Probing page cache start from offset */ + if (xfs_find_get_desired_pgoff(inode, &map[0], + DATA_OFF, &offset)) + break; + } + + /* + * Found a hole in map[0] and nothing in map[1]. + * Probably means that we are reading after EOF. + */ + if (nmap == 1) { + error = ENXIO; + goto out_unlock; + } + + /* + * We have two mappings, proceed to check map[1]. + */ + offset = max_t(loff_t, start, + XFS_FSB_TO_B(mp, map[1].br_startoff)); + if (map[1].br_state == XFS_EXT_NORM && + !isnullstartblock(map[1].br_startblock)) + break; + else { + /* + * map[1] is also an unwritten extent, lookup + * data buffer from page cache now. + */ + if (map[1].br_startblock == DELAYSTARTBLOCK || + 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