On 2020/1/6 6:14 上午, Clodoaldo Neto wrote: > I'm struggling to mount an encrypted backing device. The backing > device is a RAID 1 array at /dev/md127 and the cache device is > /dev/sdb1. > > # lsblk > NAME MAJ:MIN RM SIZE RO > TYPE MOUNTPOINT > sda 8:0 0 223.6G 0 disk > ├─sda1 8:1 0 700M 0 part /boot > ├─sda2 8:2 0 700M 0 > part /boot/efi > ├─sda3 8:3 0 26G 0 part > │ └─luks-9793c78f-723c-4218-865f-83dbc4659192 253:1 0 26G 0 crypt [SWAP] > └─sda4 8:4 0 162G 0 part > └─luks-569b1153-2fab-4984-b1b6-c4a02ee206ef 253:0 0 162G 0 crypt / > sdb 8:16 0 111.8G 0 disk > ├─sdb1 8:17 0 40G 0 part > └─sdb2 8:18 0 71.8G 0 part > sdc 8:32 0 1.8T 0 disk > └─sdc1 8:33 0 1.8T 0 part > └─md127 9:127 0 1.8T 0 raid1 > sdd 8:48 0 1.8T 0 disk > └─sdd1 8:49 0 1.8T 0 part > └─md127 9:127 0 1.8T 0 raid1 > sde 8:64 1 58.9G 0 disk > ├─sde1 8:65 1 20G 0 part > └─sde2 8:66 1 38.9G 0 part > sr0 11:0 1 1024M 0 rom > > # blkid | grep -E "md127|sdb1" > /dev/sdb1: UUID="535bfa2d-4c6e-4c19-91b2-d292872a1877" TYPE="bcache" > PARTLABEL="Linux filesystem" > PARTUUID="505789f1-0523-4c62-bdb1-81bc0cc7bff1" > /dev/md127: UUID="b17ceaac-27ec-44d8-8bbb-235cfaa0c4a4" TYPE="bcache" > > It was working right when I installed Fedora 31 yesterday but then I > resized the caching partition and I can't make it work again. > > This is what I tried > > # wipefs -a /dev/sdb1 > /dev/sdb1: 16 bytes were erased at offset 0x00001018 (bcache): c6 85 > 73 f6 4e 1a 45 ca 82 65 f5 7f 48 ba 6d 81 > > # make-bcache -C --writeback /dev/sdb1 > UUID: eb7d8e72-f24c-48ee-bad0-771afccca876 > Set UUID: 50e33260-4623-4374-9a61-c78b7d75280e > version: 0 > nbuckets: 81920 > block_size: 1 > bucket_size: 1024 > nr_in_set: 1 > nr_this_dev: 0 > first_bucket: 1 > > # ll /sys/fs/bcache/ > total 0 > drwxr-xr-x. 7 root root 0 Jan 5 18:34 50e33260-4623-4374-9a61-c78b7d75280e > --w-------. 1 root root 4096 Jan 5 17:39 pendings_cleanup > --w-------. 1 root root 4096 Jan 5 18:03 register > --w-------. 1 root root 4096 Jan 5 17:39 register_quiet > > # bcache-super-show /dev/sdb1 > sb.magic ok > sb.first_sector 8 [match] > sb.csum C4CB62916B7825CE [match] > sb.version 3 [cache device] > > dev.label (empty) > dev.uuid eb7d8e72-f24c-48ee-bad0-771afccca876 > dev.sectors_per_block 1 > dev.sectors_per_bucket 1024 > dev.cache.first_sector 1024 > dev.cache.cache_sectors 83885056 > dev.cache.total_sectors 83886080 > dev.cache.ordered yes > dev.cache.discard no > dev.cache.pos 0 > dev.cache.replacement 0 [lru] > > cset.uuid 50e33260-4623-4374-9a61-c78b7d75280e > > # echo /dev/md127 > /sys/fs/bcache/register > # echo 50e33260-4623-4374-9a61-c78b7d75280e > /sys/block/md127/bcache/attach > # blkid | grep bcache0 > /dev/bcache0: UUID="7e2c0b40-8dec-4b13-8d00-b53b55160775" TYPE="crypto_LUKS" > > # bcache-status > --- bcache --- > UUID 50e33260-4623-4374-9a61-c78b7d75280e > Block Size 512 B > Bucket Size 512.00 KiB > Congested? False > Read Congestion 2.0ms > Write Congestion 20.0ms > Total Cache Size 40 GiB > Total Cache Used 409.6 MiB (1%) > Total Cache Unused 40 GiB (99%) > Evictable Cache 40 GiB (100%) > Replacement Policy [lru] fifo random > Cache Mode writethrough [writeback] writearound none > Total Hits 9 (64%) > Total Misses 5 > Total Bypass Hits 13 (16%) > Total Bypass Misses 64 > Total Bypassed 308.00 KiB > > # lsblk > NAME MAJ:MIN RM SIZE RO > TYPE MOUNTPOINT > sda 8:0 0 223.6G 0 disk > ├─sda1 8:1 0 700M 0 part /boot > ├─sda2 8:2 0 700M 0 > part /boot/efi > ├─sda3 8:3 0 26G 0 part > │ └─luks-9793c78f-723c-4218-865f-83dbc4659192 253:1 0 26G 0 crypt [SWAP] > └─sda4 8:4 0 162G 0 part > └─luks-569b1153-2fab-4984-b1b6-c4a02ee206ef 253:0 0 162G 0 crypt / > sdb 8:16 0 111.8G 0 disk > ├─sdb1 8:17 0 40G 0 part > │ └─bcache0 252:0 0 1.8T 0 disk > └─sdb2 8:18 0 71.8G 0 part > sdc 8:32 0 1.8T 0 disk > └─sdc1 8:33 0 1.8T 0 part > └─md127 9:127 0 1.8T 0 raid1 > └─bcache0 252:0 0 1.8T 0 disk > sdd 8:48 0 1.8T 0 disk > └─sdd1 8:49 0 1.8T 0 part > └─md127 9:127 0 1.8T 0 raid1 > └─bcache0 252:0 0 1.8T 0 disk > sde 8:64 1 58.9G 0 disk > ├─sde1 8:65 1 20G 0 part > └─sde2 8:66 1 38.9G 0 part > sr0 11:0 1 1024M 0 rom > > # mount /dev/bcache0 /r > mount: /r: unknown filesystem type 'crypto_LUKS'. > > # cryptsetup open /dev/bcache0 backing-device > Enter passphrase for /dev/bcache0: > > # mount /dev/mapper/backing-device /r > mount: /r: unknown filesystem type 'bcache'. > > What am I missing? The super block location of the backing disk is occupied by bcache. You cannot mount the file system directly from the backing disk which is formated as bcache backing device, because crypto_LUKS super block is 4K later (bcache offset all I/Os on bcache device 4KB behind the requesting LBA on backing disk). Therefore you have to mount the file system from bcache device, that is /dev/bcache0 in your case. If you want to mount from /dev/mapper/backing-device, it might work if you may specify the actual file system offset is 4KB behind its original offset. -- Coly Li
