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 q7DD92HF004279 for ; Mon, 13 Aug 2012 08:09:02 -0500 Received: from rcsinet15.oracle.com (rcsinet15.oracle.com [148.87.113.117]) by cuda.sgi.com with ESMTP id tcpq78ByLRG9J94g (version=TLSv1 cipher=AES256-SHA bits=256 verify=NO) for ; Mon, 13 Aug 2012 06:09:01 -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 q7DD90a5016841 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 13 Aug 2012 13:09:01 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 q7DD90I5016075 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Mon, 13 Aug 2012 13:09:00 GMT Received: from abhmt107.oracle.com (abhmt107.oracle.com [141.146.116.59]) by acsmt358.oracle.com (8.12.11.20060308/8.12.11) with ESMTP id q7DD908d025220 for ; Mon, 13 Aug 2012 08:09:00 -0500 Message-ID: <5028FC3D.8000007@oracle.com> Date: Mon, 13 Aug 2012 21:08:13 +0800 From: Jeff Liu MIME-Version: 1.0 Subject: [PATCH v7 4/4] xfs: xfs_seek_hole() refinement with hole searching from page cache for unwritten extent 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 Improve xfs_seek_hole() to search hole offset from page cache for unwritten extents. Signed-off-by: Jie Liu --- fs/xfs/xfs_file.c | 76 +++++++++++++++++++++++++++++++++++++++++++++------- 1 files changed, 65 insertions(+), 11 deletions(-) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 43b3718..a537f61 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1288,9 +1288,9 @@ 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; @@ -1306,21 +1306,75 @@ 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; + unsigned int i; + + 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; + } + + for (i = 0; i < nmap; i++) { + offset = max_t(loff_t, start, + XFS_FSB_TO_B(mp, map[i].br_startoff)); + + /* Landed in a hole */ + if (map[i].br_startblock == HOLESTARTBLOCK) + goto out; + + /* + * Landed in an unwritten extent, try to search hole + * from page cache. + */ + if (map[i].br_state == XFS_EXT_UNWRITTEN) { + if (xfs_find_get_desired_pgoff(inode, &map[i], + HOLE_OFF, &offset)) + goto out; + } + } + + /* + * 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; + } - holeoff = XFS_FSB_TO_B(mp, fsbno); - if (holeoff <= start) - offset = start; - else { /* - * 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[i - 1].br_startoff + map[i - 1].br_blockcount; + start = XFS_FSB_TO_B(mp, fsbno); + if (start >= isize) { + offset = isize; + break; + } } +out: + /* + * 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