btrfs-tools missing "btrfs device delete devid=x path" ?

[Marc MERLIN <marc@merlins.org>]

I'm still doing some testing so that I can write some howto.

I got that far after a rebalance (mmmh, that took 2 days with little
data, and unfortunately 5 deadlocks and reboots.

polgara:/mnt/btrfs_backupcopy# btrfs fi show
Label: backupcopy  uuid: eed9b55c-1d5a-40bf-a032-1be6980648e1
        Total devices 11 FS bytes used 114.35GiB
        devid    1 size 465.76GiB used 32.14GiB path /dev/dm-0
        devid    2 size 465.76GiB used 32.14GiB path /dev/mapper/crypt_sdd1
        devid    3 size 465.75GiB used 0.00 path  <----  drive is freed up now.
        devid    4 size 465.76GiB used 32.14GiB path /dev/dm-2
        devid    5 size 465.76GiB used 32.14GiB path /dev/dm-3
        devid    6 size 465.76GiB used 32.14GiB path /dev/dm-4
        devid    7 size 465.76GiB used 32.14GiB path /dev/mapper/crypt_sdi1
        devid    8 size 465.76GiB used 32.14GiB path /dev/dm-6
        devid    9 size 465.76GiB used 32.14GiB path /dev/mapper/crypt_sdk1
        devid    10 size 465.76GiB used 32.14GiB path /dev/mapper/crypt_sdl1
        devid    11 size 465.76GiB used 32.14GiB path /dev/mapper/crypt_sde1
Btrfs v3.12

What's the syntax for removing a drive that isn't there?

I'm looking for something like
polgara:/mnt/btrfs_backupcopy# btrfs device delete devid=3 .
ERROR: error removing the device 'devid=3' - No such file or directory

Until I can remove it, not surprisingly, even though device 3 is now
unused, I still need to mount degraded:

polgara:~# mount -v -t btrfs -o compress=zlib,space_cache,noatime LABEL=backupcopy /mnt/btrfs_backupcopy
mount: wrong fs type, bad option, bad superblock on /dev/mapper/crypt_sde1,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

[28865.527656] BTRFS: open devid=3 failed
[29777.507022] BTRFS: device label backupcopy devid 11 transid 5137 /dev/mapper/crypt_sde1
[29777.558874] BTRFS info (device dm-9): disk space caching is enabled
[29777.566997] BTRFS: failed to read chunk tree on dm-9
[29777.612041] BTRFS: open_ctree failed

polgara:~# mount -v -t btrfs -o compress=zlib,space_cache,noatime,degraded LABEL=backupcopy /mnt/btrfs_backupcopy
/dev/mapper/crypt_sde1 on /mnt/btrfs_backupcopy type btrfs (rw,noatime,compress=zlib,space_cache,degraded)
polgara:~# 

This works.

I think if I get that last step working, I will have succcessfully removed a raid5
drive, added a new drive, rebalanced existing data on it, and removed the old one.

Thanks,
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