From: Qu Wenruo wqu@suse.com
commit 8bb177d18f114358a57d8ae7e206861b48b8b4de upstream.
[BUG] The following script will cause false alert on devid check. #!/bin/bash
dev1=/dev/test/test dev2=/dev/test/scratch1 mnt=/mnt/btrfs
umount $dev1 &> /dev/null umount $dev2 &> /dev/null umount $mnt &> /dev/null
mkfs.btrfs -f $dev1
mount $dev1 $mnt
_fail() { echo "!!! FAILED !!!" exit 1 }
for ((i = 0; i < 4096; i++)); do btrfs dev add -f $dev2 $mnt || _fail btrfs dev del $dev1 $mnt || _fail dev_tmp=$dev1 dev1=$dev2 dev2=$dev_tmp done
[CAUSE] Tree-checker uses BTRFS_MAX_DEVS() and BTRFS_MAX_DEVS_SYS_CHUNK() as upper limit for devid. But we can have devid holes just like above script.
So the check for devid is incorrect and could cause false alert.
[FIX] Just remove the whole devid check. We don't have any hard requirement for devid assignment.
Furthermore, even devid could get corrupted by a bitflip, we still have dev extents verification at mount time, so corrupted data won't sneak in.
This fixes fstests btrfs/194.
Reported-by: Anand Jain anand.jain@oracle.com Fixes: ab4ba2e13346 ("btrfs: tree-checker: Verify dev item") CC: stable@vger.kernel.org # 5.2+ Signed-off-by: Qu Wenruo wqu@suse.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/btrfs/tree-checker.c | 8 -------- 1 file changed, 8 deletions(-)
--- a/fs/btrfs/tree-checker.c +++ b/fs/btrfs/tree-checker.c @@ -686,9 +686,7 @@ static void dev_item_err(const struct ex static int check_dev_item(struct extent_buffer *leaf, struct btrfs_key *key, int slot) { - struct btrfs_fs_info *fs_info = leaf->fs_info; struct btrfs_dev_item *ditem; - u64 max_devid = max(BTRFS_MAX_DEVS(fs_info), BTRFS_MAX_DEVS_SYS_CHUNK);
if (key->objectid != BTRFS_DEV_ITEMS_OBJECTID) { dev_item_err(leaf, slot, @@ -696,12 +694,6 @@ static int check_dev_item(struct extent_ key->objectid, BTRFS_DEV_ITEMS_OBJECTID); return -EUCLEAN; } - if (key->offset > max_devid) { - dev_item_err(leaf, slot, - "invalid devid: has=%llu expect=[0, %llu]", - key->offset, max_devid); - return -EUCLEAN; - } ditem = btrfs_item_ptr(leaf, slot, struct btrfs_dev_item); if (btrfs_device_id(leaf, ditem) != key->offset) { dev_item_err(leaf, slot,