From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-f179.google.com ([209.85.217.179]:35618 "EHLO mail-lb0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751149AbbBDMS2 (ORCPT ); Wed, 4 Feb 2015 07:18:28 -0500 Received: by mail-lb0-f179.google.com with SMTP id z11so231709lbi.10 for ; Wed, 04 Feb 2015 04:18:27 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <1423051853-25336-1-git-send-email-forrestl@synology.com> References: <1423051853-25336-1-git-send-email-forrestl@synology.com> Date: Wed, 4 Feb 2015 20:18:26 +0800 Message-ID: Subject: Re: [PATCH v2] Btrfs: fix find_free_dev_extent() malfunction in case device tree has hole From: Forrest Liu To: linux-btrfs@vger.kernel.org Cc: Forrest Liu Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: The problem can be reproduce by following steps on 3.19-rc7 , and the patch was tested on 3.19-rc7 mntpath=/btrfs loopdev=/dev/loop0 filepath=/volume2/100g_image umount $mntpath losetup -d $loopdev truncate --size 100g $filepath losetup $loopdev $filepath mkfs.btrfs -f $loopdev mount $loopdev $mntpath 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 fallocate -l 1g $mntpath/ccc fallocate -l 1g $mntpath/ddd fallocate -l 1g $mntpath/eee Thanks, -Forrest 2015-02-04 20:10 GMT+08:00 Forrest Liu : > If device tree has hole, find_free_dev_extent() cannot find available > address properly. > > The example below, has one BIG hole in device tree, and can only > allocate just one chunk in a transaction. > > item 9 key (1 DEV_EXTENT 273841913856) itemoff 15811 itemsize 48 > dev extent chunk_tree 3 > chunk objectid 256 chunk offset 272759783424 length 1073741824 > item 10 key (1 DEV_EXTENT 1071632089088) itemoff 15763 itemsize 48 > dev extent chunk_tree 3 > chunk objectid 256 chunk offset 1070549958656 length 1073741824 > item 11 key (1 DEV_EXTENT 1072705830912) itemoff 15715 itemsize 48 > dev extent chunk_tree 3 > chunk objectid 256 chunk offset 1071623700480 length > > Signed-off-by: Forrest Liu > Reviewed-by: Liu Bo > --- > changelog: > v2: fix typo key_offset > replace WARN_ON with WARN_ON_ONCE > > fs/btrfs/volumes.c | 15 +++++++++++---- > 1 file changed, 11 insertions(+), 4 deletions(-) > > diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c > index 50c5a87..da07eca 100644 > --- a/fs/btrfs/volumes.c > +++ b/fs/btrfs/volumes.c > @@ -1060,6 +1060,7 @@ 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) { > @@ -1070,9 +1071,9 @@ 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; > @@ -1195,8 +1196,14 @@ 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; > -- > 1.9.1 >