Re: [PATCH 1/2] xfs: remove deprecated mount options

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Thu, Sep 24, 2020 at 12:39:07PM -0500, Eric Sandeen wrote:
> On 9/24/20 12:26 PM, Darrick J. Wong wrote:
> > On Thu, Sep 24, 2020 at 07:07:46PM +0200, Pavel Reichl wrote:
> >> ikeep/noikeep was a workaround for old DMAPI code which is no longer
> >> relevant.
> >>
> >> attr2/noattr2 - is for controlling upgrade behaviour from fixed attribute
> >> fork sizes in the inode (attr1) and dynamic attribute fork sizes (attr2).
> >> mkfs has defaulted to setting attr2 since 2007, hence just about every
> >> XFS filesystem out there in production right now uses attr2.
> >>
> >> Signed-off-by: Pavel Reichl <preichl@redhat.com>
> >> ---
> >>  Documentation/admin-guide/xfs.rst |  2 ++
> >>  fs/xfs/xfs_super.c                | 30 +++++++++++++++++-------------
> >>  2 files changed, 19 insertions(+), 13 deletions(-)
> >>
> >> diff --git a/Documentation/admin-guide/xfs.rst b/Documentation/admin-guide/xfs.rst
> >> index f461d6c33534..413f68efccc0 100644
> >> --- a/Documentation/admin-guide/xfs.rst
> >> +++ b/Documentation/admin-guide/xfs.rst
> >> @@ -217,6 +217,8 @@ Deprecated Mount Options
> >>  ===========================     ================
> >>    Name				Removal Schedule
> >>  ===========================     ================
> >> +  ikeep/noikeep			TBD
> >> +  attr2/noattr2			TBD
> > 
> > Er... what date did you have in mind?

June 65th, 2089 it is, then. ;)

> >>  ===========================     ================
> >>  
> >>  
> >> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> >> index 71ac6c1cdc36..4c26b283b7d8 100644
> >> --- a/fs/xfs/xfs_super.c
> >> +++ b/fs/xfs/xfs_super.c
> >> @@ -1234,25 +1234,12 @@ xfs_fc_parse_param(
> >>  	case Opt_nouuid:
> >>  		mp->m_flags |= XFS_MOUNT_NOUUID;
> >>  		return 0;
> >> -	case Opt_ikeep:
> >> -		mp->m_flags |= XFS_MOUNT_IKEEP;
> >> -		return 0;
> >> -	case Opt_noikeep:
> >> -		mp->m_flags &= ~XFS_MOUNT_IKEEP;
> >> -		return 0;
> >>  	case Opt_largeio:
> >>  		mp->m_flags |= XFS_MOUNT_LARGEIO;
> >>  		return 0;
> >>  	case Opt_nolargeio:
> >>  		mp->m_flags &= ~XFS_MOUNT_LARGEIO;
> >>  		return 0;
> >> -	case Opt_attr2:
> >> -		mp->m_flags |= XFS_MOUNT_ATTR2;
> >> -		return 0;
> >> -	case Opt_noattr2:
> >> -		mp->m_flags &= ~XFS_MOUNT_ATTR2;
> >> -		mp->m_flags |= XFS_MOUNT_NOATTR2;
> >> -		return 0;
> >>  	case Opt_filestreams:
> >>  		mp->m_flags |= XFS_MOUNT_FILESTREAMS;
> >>  		return 0;
> >> @@ -1304,6 +1291,23 @@ xfs_fc_parse_param(
> >>  		xfs_mount_set_dax_mode(mp, result.uint_32);
> >>  		return 0;
> >>  #endif
> >> +	case Opt_ikeep:
> >> +		xfs_warn(mp, "%s mount option is deprecated.", param->key);
> >> +		mp->m_flags |= XFS_MOUNT_IKEEP;
> > 
> > It's a little odd that you didn't then remove these XFS_MOUNT_ flags.
> > It's strange to declare a mount option deprecated but still have it
> > change behavior.
> 
> but ... this doesn't change behavior, right?  The flag is still set.
> 
> I think it makes sense to announce deprecation, with a date set for future
> removal, but keep all other behavior the same.  That gives people who still
> need it (if any exist) time to complain, right?

Ok.  I'm fine with these knobs continuing to affect xfs behavior right
up to the deprecation date.

> > In this case, I guess we should keep ikeep/noikeep in the mount options
> > table so that scripts won't fail, but then we remove XFS_MOUNT_IKEEP and
> > change the codebase to always take the IKEEP behavior and delete the
> > code that handled the !IKEEP behavior.
> > 
> >> +		return 0;
> >> +	case Opt_noikeep:
> >> +		xfs_warn(mp, "%s mount option is deprecated.", param->key);
> >> +		mp->m_flags &= ~XFS_MOUNT_IKEEP;
> >> +		return 0;
> >> +	case Opt_attr2:
> >> +		xfs_warn(mp, "%s mount option is deprecated.", param->key);
> >> +		mp->m_flags |= XFS_MOUNT_ATTR2;

Side note: shouldn't this clause be clearing XFS_MOUNT_NOATTR2?

> > 
> > If the kernel /does/ encounter an attr1 filesystem, what will it do now?
> 
> The same as it did yesterday; the flag is still set for now.
> 
> > IIRC the default (if there is no attr2/noattr2 mount option) is to
> > auto-upgrade the fs, right?  So will we stop doing that, or are we
> > making the upgrade mandatory now?
> > 
> >> +		return 0;
> >> +	case Opt_noattr2:
> >> +		xfs_warn(mp, "%s mount option is deprecated.", param->key);
> >> +		mp->m_flags &= ~XFS_MOUNT_ATTR2;
> >> +		mp->m_flags |= XFS_MOUNT_NOATTR2;
> > 
> > Also, uh, why move these code hunks?
> 
> That's my fault, I had suggested moving all the deprecated options to the end.
> 
> Maybe with a comment, /* REMOVE ME 2089 */ or whatever we pick?

Ah.

--D

> -Eric