When I try to run any of the commands like init-csum-tree etc the
btrfs program core dumps. Here is an example

root@NAS:/root# btrfsck --init-csum-tree /dev/sdb1
Creating a new CRC tree
warning, device 2 is missing
parent transid verify failed on 8388608 wanted 136966 found 136967
parent transid verify failed on 8388608 wanted 136966 found 136967
Ignoring transid failure
Checking filesystem on /dev/sdb1
UUID: f89c12fb-2304-4dce-bed5-fda008b86bde
Reinitialize checksum tree
extent-tree.c:2703: btrfs_reserve_extent: BUG_ON `ret` triggered, value -28
btrfs check[0x44e371]
btrfs check(btrfs_reserve_extent+0xbc6)[0x4540e6]
btrfs check(btrfs_alloc_free_block+0x5a)[0x45415c]
btrfs check[0x41d788]
btrfs check(cmd_check+0x1270)[0x430633]
btrfs check(main+0x155)[0x40a813]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0)[0x7f4a89555830]
btrfs check(_start+0x29)[0x40a409]
Aborted (core dumped)




On Sun, Jan 29, 2017 at 8:12 AM, Subscription Account
[off-list ref] wrote:

Hi,

I had to remove one disk from raid 1 and I rebooted the system and was
able to mount in degraded mode. Then I powered off the system added a
new disk and when I am trying to mount the btrfs filesystem in
degraded mode it will no longer mount it read-write. I can mount
read-only though.

I tried running btrfs-zero-log as well and that gices a core dump.

My system details as follows:

rajeev@NAS:~$ uname -a
Linux NAS 4.4.0-59-generic #80-Ubuntu SMP Fri Jan 6 17:47:47 UTC 2017
x86_64 x86_64 x86_64 GNU/Linux

root@NAS:~# btrfs --version
Btrfs v3.12

root@NAS:~# btrfs fi show
Label: none  uuid: f89c12fb-2304-4dce-bed5-fda008b86bde
        Total devices 2 FS bytes used 2.49TiB
        devid    1 size 2.73TiB used 2.52TiB path /dev/sdb1
        *** Some devices missing

Btrfs v3.12

root@NAS:~# mount -o degraded /dev/sdb1 /local/nas
mount: wrong fs type, bad option, bad superblock on /dev/sdb1,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.

root@NAS:~# dmesg | tail
[ 2506.816795] BTRFS: missing devices(1) exceeds the limit(0),
writeable mount is not allowed
[ 2506.878031] BTRFS: open_ctree failed
[ 4590.339548] BTRFS info (device sdb1): allowing degraded mounts
[ 4590.505739] BTRFS info (device sdb1): bdev /dev/sdb1 errs: wr 0, rd
90, flush 0, corrupt 0, gen 0
[ 4609.481310] BTRFS: missing devices(1) exceeds the limit(0),
writeable mount is not allowed
[ 4609.536509] BTRFS: open_ctree failed
[ 4852.498305] BTRFS info (device sdb1): allowing degraded mounts
[ 4853.294311] BTRFS info (device sdb1): bdev /dev/sdb1 errs: wr 0, rd
90, flush 0, corrupt 0, gen 0
[ 4873.026855] BTRFS: missing devices(1) exceeds the limit(0),
writeable mount is not allowed
[ 4873.083840] BTRFS: open_ctree failed

root@NAS:~# mount -o degraded,ro /dev/sdb1 /local/nas

root@NAS:~# btrfs fi df /local/nas
Data, RAID1: total=2.51TiB, used=2.49TiB
Data, single: total=1.01GiB, used=88.27MiB
System, RAID1: total=8.00MiB, used=352.00KiB
System, single: total=4.00MiB, used=12.00KiB
Metadata, RAID1: total=6.00GiB, used=5.01GiB
Metadata, single: total=8.00MiB, used=3.31MiB
unknown, single: total=512.00MiB, used=0.00

In the read-only mode I am not able to add a new device or replace :(.
Please help.

Thanks,

--
raj