From 1b9845081633072c18f30d8cfd09c267adf0b109 Mon Sep 17 00:00:00 2001 From: Forrest Liu Date: Mon, 9 Feb 2015 17:30:47 +0800 Subject: 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 Reviewed-by: Liu Bo Signed-off-by: Chris Mason --- fs/btrfs/volumes.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) (limited to 'fs') 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; -- cgit v1.2.3-59-g8ed1b