Re: 64-btrfs.rules and degraded boot

[Goffredo Baroncelli <kreijack@inwind.it>]

On 2016-07-06 22:00, Chris Murphy wrote:
> On Wed, Jul 6, 2016 at 1:17 PM, Austin S. Hemmelgarn
> <ahferroin7@gmail.com> wrote:
> 
>> In bash or most other POSIX compliant shells, you can run this:
>> echo $?
>> to get the return code of the previous command.
>>
>> In your case though, it may be reporting the FS ready because it had already
>> seen all the devices, IIUC, the flag that checks is only set once, and never
>> unset, which is not a good design in this case.
> 
> Oh dear.
> 
> [root@f24s ~]# lvs
>   LV         VG Attr       LSize  Pool       Origin Data%  Meta%  Move
> Log Cpy%Sync Convert
>   1          VG Vwi---tz-- 50.00g thintastic
>   2          VG Vwi---tz-- 50.00g thintastic
>   3          VG Vwi-a-tz-- 50.00g thintastic        2.54
>   thintastic VG twi-aotz-- 90.00g                   5.05   2.92
> [root@f24s ~]# btrfs dev scan
> Scanning for Btrfs filesystems
> [root@f24s ~]# echo $?
> 0
> [root@f24s ~]# btrfs device ready /dev/mapper/VG-3
> [root@f24s ~]# echo $?
> 0
> [root@f24s ~]# btrfs fi show
> warning, device 2 is missing
> Label: none  uuid: 96240fd9-ea76-47e7-8cf4-05d3570ccfd7
>     Total devices 3 FS bytes used 2.26GiB
>     devid    3 size 50.00GiB used 3.01GiB path /dev/mapper/VG-3
>     *** Some devices missing
> 
> 
> Cute, device 1 is also missing but that's not mentioned. In any case,
> the device is still ready even after a dev scan. I guess this isn't
> exactly testable all that easily unless I reboot.

IIRC a device when "registered" by "btrfs dev scan", is never removed from the available devices. This means that if you remove a valid device after that it is already scanned, "btrfs dev ready" still return OK until a reboot happened.

>From your email, it is not clear if you rebooted (or rmmod-ded btrfs) after you removed the devices.

Only my 2¢...

BR
G.Baroncelli
> 
> 
> 


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