On 04/10/2019 09:11, Nikolay Borisov wrote: > > > On 4.10.19 г. 10:50 ч., Anand Jain wrote: >> btrfs_free_extra_devids() reorgs fs_devices::latest_bdev >> to point to the bdev with greatest device::generation number. >> For a typical-missing device the generation number is zero so >> fs_devices::latest_bdev will never point to it. >> >> But if the missing device is due to alienating [1], then >> device::generation is not-zero and if it is >= to rest of >> device::generation in the list, then fs_devices::latest_bdev >> ends up pointing to the missing device and reports the error >> like this [2] >> >> [1] >> mkfs.btrfs -fq /dev/sdd && mount /dev/sdd /btrfs >> mkfs.btrfs -fq -draid1 -mraid1 /dev/sdb /dev/sdc >> sleep 3 # avoid racing with udev's useless scans if needed >> btrfs dev add -f /dev/sdb /btrfs > > Hm, here I think the correct way is to refuse adding /dev/sdb to an > existing fs if it's detected to be part of a different one. I.e it > should require wipefs to be done.
I disagree. -f means "force overwrite of existing filesystem on the given disk(s)". It shouldn't be any different whether the existing fs is btrfs or something else. Graham
