Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932807Ab0FQI4U (ORCPT ); Thu, 17 Jun 2010 04:56:20 -0400 Received: from rcsinet10.oracle.com ([148.87.113.121]:33583 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932663Ab0FQI4S (ORCPT ); Thu, 17 Jun 2010 04:56:18 -0400 From: Tao Ma To: xfs@oss.sgi.com Cc: linux-kernel@vger.kernel.org, Tao Ma , Dave Chinner , Alex Elder , Christoph Hellwig , Eric Sandeen Subject: Re: [PATCH v2] xfs: Make fiemap works with sparse file. Date: Thu, 17 Jun 2010 16:53:19 +0800 Message-Id: <1276764799-4837-1-git-send-email-tao.ma@oracle.com> X-Mailer: git-send-email 1.7.0.4 In-Reply-To: <20100614122912.GD6590@dastard> References: <20100614122912.GD6590@dastard> X-Auth-Type: Internal IP X-Source-IP: acsinet15.oracle.com [141.146.126.227] X-CT-RefId: str=0001.0A090202.4C19E316.0040:SCFMA922111,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4324 Lines: 114 Hi Dave, On 06/14/2010 08:29 PM, Dave Chinner wrote: > I just had a thought - if you want to avoid holes being reported to > fiemap, then add a BMV_IF_NO_HOLES flag to xfs_getbmap() and skip > holes in the mappin gloop when this flag is set. That will make > fiemap fill in the full number of extents without hacking the > extent count... Here is the updated one. I have used BVM_IF_NO_HOLES in xfs_getbmap to skip increasing index 'cur_ext'. It is a bit ugly, see my commit log. I guess maybe we can add another flag in xfs_bmapi so that it don't even give us the holes? Regards, Tao >From cee1765ffd3e2b003b837666b4620b5107ed9ddd Mon Sep 17 00:00:00 2001 From: Tao Ma Date: Thu, 17 Jun 2010 16:14:22 +0800 Subject: [PATCH v3] xfs: Make fiemap works with sparse file. In xfs_vn_fiemap, we set bvm_count to fi_extent_max + 1 and want to return fi_extent_max extents, but actually it won't work for a sparse file. The reason is that in xfs_getbmap we will calculate holes and set it in 'out', while out is malloced by bmv_count(fi_extent_max+1) which didn't consider holes. So in the worst case, if 'out' vector looks like [hole, extent, hole, extent, hole, ... hole, extent, hole], we will only return half of fi_extent_max extents. This patch add a new parameter BMV_IF_NO_HOLES for bvm_iflags. So with this flags, we don't use our 'out' in xfs_getbmap for a hole. The solution is a bit ugly by just don't increasing index of 'out' vector. I felt that it is not easy to skip it at the very beginning since we have the complicated check and some function like xfs_getbmapx_fix_eof_hole to adjust 'out'. Cc: Dave Chinner Cc: Alex Elder Cc: Christoph Hellwig Cc: Eric Sandeen Signed-off-by: Tao Ma --- fs/xfs/linux-2.6/xfs_iops.c | 2 +- fs/xfs/xfs_bmap.c | 14 +++++++++++++- fs/xfs/xfs_fs.h | 4 +++- 3 files changed, 17 insertions(+), 3 deletions(-) diff --git a/fs/xfs/linux-2.6/xfs_iops.c b/fs/xfs/linux-2.6/xfs_iops.c index 9c8019c..505d5c0 100644 --- a/fs/xfs/linux-2.6/xfs_iops.c +++ b/fs/xfs/linux-2.6/xfs_iops.c @@ -677,7 +677,7 @@ xfs_vn_fiemap( fieinfo->fi_extents_max + 1; bm.bmv_count = min_t(__s32, bm.bmv_count, (PAGE_SIZE * 16 / sizeof(struct getbmapx))); - bm.bmv_iflags = BMV_IF_PREALLOC; + bm.bmv_iflags = BMV_IF_PREALLOC | BMV_IF_NO_HOLES; if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) bm.bmv_iflags |= BMV_IF_ATTRFORK; if (!(fieinfo->fi_flags & FIEMAP_FLAG_SYNC)) diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c index 99587de..d49107d 100644 --- a/fs/xfs/xfs_bmap.c +++ b/fs/xfs/xfs_bmap.c @@ -5744,12 +5744,24 @@ xfs_getbmap( map[i].br_startblock)) goto out_free_map; - nexleft--; bmv->bmv_offset = out[cur_ext].bmv_offset + out[cur_ext].bmv_length; bmv->bmv_length = max_t(__int64_t, 0, bmvend - bmv->bmv_offset); + + /* + * In case we don't want to return the hole, + * don't increase cur_ext so that we can reuse + * it in the next loop. + */ + if ((iflags & BMV_IF_NO_HOLES) && + out[cur_ext].bmv_block == -1LL) { + memset(&out[cur_ext], 0, sizeof(out[cur_ext])); + continue; + } + + nexleft--; bmv->bmv_entries++; cur_ext++; } diff --git a/fs/xfs/xfs_fs.h b/fs/xfs/xfs_fs.h index 7cf7220..87c2e9d 100644 --- a/fs/xfs/xfs_fs.h +++ b/fs/xfs/xfs_fs.h @@ -114,8 +114,10 @@ struct getbmapx { #define BMV_IF_NO_DMAPI_READ 0x2 /* Do not generate DMAPI read event */ #define BMV_IF_PREALLOC 0x4 /* rtn status BMV_OF_PREALLOC if req */ #define BMV_IF_DELALLOC 0x8 /* rtn status BMV_OF_DELALLOC if req */ +#define BMV_IF_NO_HOLES 0x10 /* Do not return holes */ #define BMV_IF_VALID \ - (BMV_IF_ATTRFORK|BMV_IF_NO_DMAPI_READ|BMV_IF_PREALLOC|BMV_IF_DELALLOC) + (BMV_IF_ATTRFORK|BMV_IF_NO_DMAPI_READ|BMV_IF_PREALLOC| \ + BMV_IF_DELALLOC|BMV_IF_NO_HOLES) /* bmv_oflags values - returned for each non-header segment */ #define BMV_OF_PREALLOC 0x1 /* segment = unwritten pre-allocation */ -- 1.5.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/