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authorForrest Liu <forrestl@synology.com>2015-02-09 17:30:47 +0800
committerChris Mason <clm@fb.com>2015-04-26 06:26:59 -0700
commit1b9845081633072c18f30d8cfd09c267adf0b109 (patch)
tree7f323994cb18808d9f557ac4e932d21b8052a5f9 /fs
parente4c88f007be78d38eaef316c599a1ee2f0272c15 (diff)
downloadlinux-1b9845081633072c18f30d8cfd09c267adf0b109.tar.bz2
Btrfs: fix find_free_dev_extent() malfunction in case device tree has hole
If device tree has hole, find_free_dev_extent() cannot find available address properly. The problem can be reproduce by following script. mntpath=/btrfs loopdev=/dev/loop0 filepath=/home/forrest/image umount $mntpath losetup -d $loopdev truncate --size 100g $filepath losetup $loopdev $filepath mkfs.btrfs -f $loopdev mount $loopdev $mntpath # make device tree with one big hole for i in `seq 1 1 100`; do fallocate -l 1g $mntpath/$i done sync for i in `seq 1 1 95`; do rm $mntpath/$i done sync # wait cleaner thread remove unused block group sleep 300 fallocate -l 1g $mntpath/aaa # failed to allocate new chunk fallocate -l 1g $mntpath/bbb Above script will make device tree with one big hole, and can only allocate just one chunk in a transaction, so failed to allocate new chunk for $mntpath/bbb item 8 key (1 DEV_EXTENT 2185232384) itemoff 15859 itemsize 48 dev extent chunk_tree 3 chunk objectid 256 chunk offset 106292051968 length 1073741824 item 9 key (1 DEV_EXTENT 104190705664) itemoff 15811 itemsize 48 dev extent chunk_tree 3 chunk objectid 256 chunk offset 103108575232 length 1073741824 Signed-off-by: Forrest Liu <forrestl@synology.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/volumes.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 8bcd2a007517..96aebf3bcd5b 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1058,6 +1058,7 @@ static int contains_pending_extent(struct btrfs_trans_handle *trans,
struct extent_map *em;
struct list_head *search_list = &trans->transaction->pending_chunks;
int ret = 0;
+ u64 physical_start = *start;
again:
list_for_each_entry(em, search_list, list) {
@@ -1068,9 +1069,9 @@ again:
for (i = 0; i < map->num_stripes; i++) {
if (map->stripes[i].dev != device)
continue;
- if (map->stripes[i].physical >= *start + len ||
+ if (map->stripes[i].physical >= physical_start + len ||
map->stripes[i].physical + em->orig_block_len <=
- *start)
+ physical_start)
continue;
*start = map->stripes[i].physical +
em->orig_block_len;
@@ -1193,8 +1194,14 @@ again:
*/
if (contains_pending_extent(trans, device,
&search_start,
- hole_size))
- hole_size = 0;
+ hole_size)) {
+ if (key.offset >= search_start) {
+ hole_size = key.offset - search_start;
+ } else {
+ WARN_ON_ONCE(1);
+ hole_size = 0;
+ }
+ }
if (hole_size > max_hole_size) {
max_hole_start = search_start;