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authorTao Ma <tao.ma@oracle.com>2010-08-30 04:44:03 +0200
committerAlex Elder <aelder@sgi.com>2010-09-03 16:02:11 +0200
commit9af25465081480a75824fd7a16a37a5cfebeede9 (patch)
tree475ea0ef9247b65b0ce8997ba581a87bd71c11b6 /fs/xfs/xfs_bmap.c
parentxfs: Disallow 32bit project quota id (diff)
downloadlinux-9af25465081480a75824fd7a16a37a5cfebeede9.tar.xz
linux-9af25465081480a75824fd7a16a37a5cfebeede9.zip
xfs: Make fiemap work with sparse files
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 <david@fromorbit.com> Signed-off-by: Tao Ma <tao.ma@oracle.com> Signed-off-by: Alex Elder <aelder@sgi.com>
Diffstat (limited to 'fs/xfs/xfs_bmap.c')
-rw-r--r--fs/xfs/xfs_bmap.c14
1 files changed, 13 insertions, 1 deletions
diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c
index 23f14e595c18..f90dadd5a968 100644
--- a/fs/xfs/xfs_bmap.c
+++ b/fs/xfs/xfs_bmap.c
@@ -5533,12 +5533,24 @@ 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) &&
+ map[i].br_startblock == HOLESTARTBLOCK) {
+ memset(&out[cur_ext], 0, sizeof(out[cur_ext]));
+ continue;
+ }
+
+ nexleft--;
bmv->bmv_entries++;
cur_ext++;
}