fsck: bch2_parse_mount_opts() Bad mount option read_only

fsck: bch2_parse_mount_opts() Bad mount option read_only

[Alec Moskvin]

On Linux 6.7.0 with the latest bcachefs-tools 1.4.0, I get an error when 
trying to run fsck:

    bcachefs fsck -v /dev/sda3
    bch2_parse_mount_opts() Bad mount option read_only

If I try a newer git revision of bcachefs-tools, it works but does an 
upgrade of the fs version:

    bcachefs fsck /dev/sda3
    mounting version 1.3: rebalance_work opts=ro,compression=zstd:15,degraded,verbose,fsck,fix_errors=ask,read_only
    recovering from clean shutdown, journal seq 116268
    Doing compatible version upgrade from 1.3: rebalance_work to 1.4: member_seq 

and then when I mount it, it downgrades:

    [Jan14 11:06] bcachefs (sda3): mounting version 1.4: (unknown version) opts=compression=zstd:15
    [  +0.000016] bcachefs (sda3): recovering from clean shutdown, journal seq 116272
    [  +0.000003] bcachefs (sda3): Version downgrade required:
    
    [  +0.200171] bcachefs (sda3): alloc_read... done

Is there a correspondence between the kernel and bcachefs-tools 
versions? I.e., should bcachefs-tools 1.3.6 be used until a kernel with 
bcachefs 1.4 is released?

Thanks,
Alec

Re: fsck: bch2_parse_mount_opts() Bad mount option read_only

[Kent Overstreet]

On Sun, Jan 14, 2024 at 06:55:03PM -0500, Alec Moskvin wrote:
> On Linux 6.7.0 with the latest bcachefs-tools 1.4.0, I get an error when 
> trying to run fsck:
> 
>     bcachefs fsck -v /dev/sda3
>     bch2_parse_mount_opts() Bad mount option read_only
> 
> If I try a newer git revision of bcachefs-tools, it works but does an 
> upgrade of the fs version:
> 
>     bcachefs fsck /dev/sda3
>     mounting version 1.3: rebalance_work opts=ro,compression=zstd:15,degraded,verbose,fsck,fix_errors=ask,read_only
>     recovering from clean shutdown, journal seq 116268
>     Doing compatible version upgrade from 1.3: rebalance_work to 1.4: member_seq 
> 
> and then when I mount it, it downgrades:
> 
>     [Jan14 11:06] bcachefs (sda3): mounting version 1.4: (unknown version) opts=compression=zstd:15
>     [  +0.000016] bcachefs (sda3): recovering from clean shutdown, journal seq 116272
>     [  +0.000003] bcachefs (sda3): Version downgrade required:
>     
>     [  +0.200171] bcachefs (sda3): alloc_read... done
> 
> Is there a correspondence between the kernel and bcachefs-tools 
> versions? I.e., should bcachefs-tools 1.3.6 be used until a kernel with 
> bcachefs 1.4 is released?

No, for now I've been focusing on making the upgrade/downgrade process
work smoothly and reliably; and in this case 1.4 just introduced the
bch_member->seq field so there's no work to do on upgrade/downgrade -
the new version just indicates that the bch_member->seq field can be
trusted for split brain detection.

So - using mismatched kernel/tools is completely fine.