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 q736BxoL044888 for ; Fri, 3 Aug 2012 01:11:59 -0500 Received: from rcsinet15.oracle.com (rcsinet15.oracle.com [148.87.113.117]) by cuda.sgi.com with ESMTP id Pb4r7ZXuCZxQ7agP (version=TLSv1 cipher=AES256-SHA bits=256 verify=NO) for ; Thu, 02 Aug 2012 23:11:58 -0700 (PDT) Received: from ucsinet21.oracle.com (ucsinet21.oracle.com [156.151.31.93]) by rcsinet15.oracle.com (Sentrion-MTA-4.2.2/Sentrion-MTA-4.2.2) with ESMTP id q736BvDx006544 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 3 Aug 2012 06:11:58 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 q736Bv6g022424 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Fri, 3 Aug 2012 06:11:57 GMT Received: from abhmt117.oracle.com (abhmt117.oracle.com [141.146.116.69]) by acsmt356.oracle.com (8.12.11.20060308/8.12.11) with ESMTP id q736Bu4M019467 for ; Fri, 3 Aug 2012 01:11:56 -0500 Message-ID: <501B6B82.10405@oracle.com> Date: Fri, 03 Aug 2012 14:11:14 +0800 From: Jeff Liu MIME-Version: 1.0 Subject: [PATCH v6 4/4] xfs: xfs_seek_hole() refinement 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 xfs_seek_hole() refinement with hole searching from page cache for unwritten extent. Signed-off-by: Jie Liu --- fs/xfs/xfs_file.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++------- 1 files changed, 69 insertions(+), 10 deletions(-) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index e852e52..0ab27eb 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1295,9 +1295,9 @@ 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; @@ -1313,21 +1313,80 @@ 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 */ + if (map[0].br_startblock == HOLESTARTBLOCK) + break; + /* - * xfs_bmap_first_unused() could return a value bigger than - * isize if there are no more holes past the supplied offset. + * Landed in an unwritten extent, try to search hole from + * page cache. */ - offset = min_t(loff_t, holeoff, isize); + if (map[0].br_state == XFS_EXT_UNWRITTEN) { + if (xfs_find_get_desired_pgoff(inode, &map[0], + HOLE_OFF, &offset)) + break; + } + + /* + * map[0] contains data or its unwritten but contains + * data in page cache, probably means that we are + * reading after EOF. 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; + + if (map[1].br_state == XFS_EXT_UNWRITTEN) { + if (xfs_find_get_desired_pgoff(inode, &map[1], + HOLE_OFF, &offset)) + break; + } + + /* + * Both mappings contains data, proceed to the next round of + * search if the current 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) { + offset = isize; + break; + } } + /* + * At this point, we must have found a hole. However, the returned + * offset may be bigger than the file size as it may be aligned to + * page boundary for unwritten 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