Marc MERLIN
2014-Mar-23 18:09 UTC
Cannot add device "is mounted" for unmounted drive that used to be in raidset that is mounted
I found out that a drive that used to be part of a raid system that is mounted and running without it, btrfs apparently decides that the drive is part of the mounted raidset and in use. As a result, I had to eventually dd 0's over it, btrfs device scan, and finally I was able to use it again. btrfs should probably improve its check to see that the drive is not really used and let me format it. Longer details: On a running system, I re-added a drive, it showed up as /dev/sdm1 I decrypted it cryptsetup luksOpen /dev/sdm1 crypt_sdm1 But I can't add it: polgara:/mnt/btrfs_backupcopy# btrfs device add -f /dev/mapper/crypt_sdm1 . /dev/mapper/crypt_sdm1 is mounted however, I can format it as ext4, mount it, write to it, unmount it, and I still get the same error: polgara:/mnt/btrfs_backupcopy# mke2fs -t ext4 /dev/mapper/crypt_sdm1 polgara:/mnt/btrfs_backupcopy# mount /dev/mapper/crypt_sdm1 /mnt/mnt polgara:/mnt/btrfs_backupcopy# Mar 23 10:48:31 polgara kernel: [38645.955263] EXT4-fs (dm-10): mounted filesystem with ordered data mode. Opts: (null) polgara:/mnt/btrfs_backupcopy# umount /mnt/mnt polgara:/mnt/btrfs_backupcopy# btrfs device add -f /dev/mapper/crypt_sdm1 . /dev/mapper/crypt_sdm1 is mounted polgara:/mnt/btrfs_backupcopy# fuser -v /dev/mapper/crypt_sdm1 polgara:/mnt/btrfs_backupcopy# lsof -n | grep -E '(dm-10|sdm)' polgara:/mnt/btrfs_backupcopy# mkfs.btrfs -f /dev/mapper/crypt_sdm1 Error: /dev/mapper/crypt_sdm1 is mounted polgara:/mnt/btrfs_backupcopy# In the end, I had to run dd if=/dev/zero of=/dev/mapper/crypt_sdm1 bs=1M for btrfs to stop telling me the filesystem was mounted. Marc -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Microsoft is to operating systems .... .... what McDonalds is to gourmet cooking Home page: http://marc.merlins.org/ | PGP 1024R/763BE901 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html