Re: [PATCH v1 09/17] xfs: extent transaction reservations for parent attributes

[Dave Chinner <david@fromorbit.com>]

On Sat, Jun 11, 2022 at 02:41:52AM -0700, Allison Henderson wrote:
> We need to add, remove or modify parent pointer attributes during
> create/link/unlink/rename operations atomically with the dirents in the
> parent directories being modified. This means they need to be modified
> in the same transaction as the parent directories, and so we need to add
> the required space for the attribute modifications to the transaction
> reservations.
> 
> [achender: rebased, added xfs_sb_version_hasparent stub]
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
> ---
>  fs/xfs/libxfs/xfs_format.h     |   5 ++
>  fs/xfs/libxfs/xfs_trans_resv.c | 103 +++++++++++++++++++++++++++------
>  fs/xfs/libxfs/xfs_trans_resv.h |   1 +
>  3 files changed, 90 insertions(+), 19 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
> index afdfc8108c5f..96976497306c 100644
> --- a/fs/xfs/libxfs/xfs_format.h
> +++ b/fs/xfs/libxfs/xfs_format.h
> @@ -390,6 +390,11 @@ xfs_sb_has_incompat_feature(
>  	return (sbp->sb_features_incompat & feature) != 0;
>  }
>  
> +static inline bool xfs_sb_version_hasparent(struct xfs_sb *sbp)
> +{
> +	return false; /* We'll enable this at the end of the set */
> +}

Just noticed this in passing - I have not looked at the reservation
calculations at all yet. We don't use "xfs_sb_version" feature
checks anymore. This goes into xfs_mount.h as a feature flag and we
use xfs_has_parent_pointers(mp) to check for the feature rather that
superblock bits.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com