On 27/8/19 4:12 PM, Qu Wenruo wrote:
On 2019/8/27 下午3:40, Anand Jain wrote:
In a corrupted tree if search for next devid finds the device with
devid = -1, then report the error -EUCLEAN back to the parent
function to fail gracefully.
Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
---
fs/btrfs/volumes.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 4db4a100c05b..36aa5f79fb6c 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1849,7 +1849,12 @@ static noinline int find_next_devid(struct btrfs_fs_info *fs_info,
if (ret < 0)
goto error;
- BUG_ON(ret == 0); /* Corruption */
+ if (ret == 0) {
+ /* Corruption */
+ btrfs_err(fs_info, "corrupted chunk tree devid -1 matched");
It will never hit this branch.
As in tree checker, we have checked if the devid is so large that a
chunk item or system chunk array can't contain one.
That check is buggy. It assumes devid represents the num_devices,
it does not account for the possible devid hole as created in the
below script.
$ cat t
umount /btrfs
dev1=/dev/sdb
dev2=/dev/sdc
mkfs.btrfs -fq -dsingle -msingle $dev1
mount $dev1 /btrfs
_fail()
{
echo $1
exit 1
}
while true; do
btrfs dev add -f $dev2 /btrfs || _fail "add failed"
btrfs dev del $dev1 /btrfs || _fail "del failed"
dev_tmp=$dev1
dev1=$dev2
dev2=$dev_tmp
done
-----------------------
[ 185.446441] BTRFS critical (device sdb): corrupt leaf: root=3
block=313739198464 slot=1 devid=1 invalid devid: has=507 expect=[0, 506]
[ 185.446446] BTRFS error (device sdb): block=313739198464 write time
tree block corruption detected
[ 185.446556] BTRFS: error (device sdb) in
btrfs_commit_transaction:2268: errno=-5 IO failure (Error while writing
out transaction)
[ 185.446559] BTRFS warning (device sdb): Skipping commit of aborted
transaction.
[ 185.446561] BTRFS: error (device sdb) in cleanup_transaction:1827:
errno=-5 IO failure
-----------------------
Thanks, Anand
That limit is way smaller than (u64)-1.
Thus if we really have a key (DEV_ITEMS DEV_ITEM -1), it will be
rejected by tree-checker in the first place, thus you will get a ret ==
-EUCLEAN from previous btrfs_search_slot() call.
Thanks,
Qu
+ ret = -EUCLEAN;
+ goto error;
+ }
ret = btrfs_previous_item(fs_info->chunk_root, path,
BTRFS_DEV_ITEMS_OBJECTID,
