Re: [PATCH 10/17] :xfs: extent transaction reservations for parent attributes

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

On Wed, Oct 18, 2017 at 03:55:26PM -0700, Allison Henderson wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> 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 ++++++++++++++++++++++++++++++++---------
>  2 files changed, 85 insertions(+), 23 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
> index b9ea5bf..121862a 100644
> --- a/fs/xfs/libxfs/xfs_format.h
> +++ b/fs/xfs/libxfs/xfs_format.h
> @@ -556,6 +556,11 @@ static inline bool xfs_sb_version_hasreflink(struct xfs_sb *sbp)
>  		(sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_REFLINK);
>  }
>  
> +static inline bool xfs_sb_version_hasparent(struct xfs_sb *sbp)
> +{
> +	return false; /* We'll enable this at the end of the set */

I think this chunk should just add the proper testing code here.

You only add RO_COMPAT_PARENT to XFS_SB_FEAT_RO_COMPAT_ALL at the end of
the patch series, so anyone bisecting their way through the series won't
be able to mount such an fs.

> +}
> +
>  /*
>   * end of superblock version macros
>   */
> diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c
> index 6bd916b..54399e2 100644
> --- a/fs/xfs/libxfs/xfs_trans_resv.c
> +++ b/fs/xfs/libxfs/xfs_trans_resv.c
> @@ -802,29 +802,30 @@ xfs_calc_sb_reservation(
>  	return xfs_calc_buf_res(1, mp->m_sb.sb_sectsize);
>  }
>  
> +/*
> + * Namespace reservations.
> + *
> + * These get tricky when parent pointers are enabled as we have attribute
> + * modifications occurring from within these transactions. Rather than confuse
> + * each of these reservation calculations with the conditional attribute
> + * reservations, add them here in a clear and concise manner. This assumes that
> + * the attribute reservations have already been calculated.
> + *
> + * Note that we only include the static attribute reservation here; the runtime
> + * reservation will have to be modified by the size of the attributes being
> + * added/removed/modified. See the comments on the attribute reservation
> + * calculations for more details.

I don't know that we can properly use a different runtime reservations
than what we statically reserve here, since the static reservations are
used to ensure that the log is of sufficient size given the fs geometry.

<shrug> Maybe we can figure out how much extra space is allowable given
the actual size of the log?  Or perhaps in the end we'll just end up
restricting the maximum size of what we can log through intents?  Or
just set the reservation to 64k I guess.... :)

--D

> + * Note for rename: rename will vastly overestimate requirements. This will be
> + * addressed later when modifications are made to ensure parent attribute
> + * modifications can be done atomically with the rename operation.
> + */
>  void
> -xfs_trans_resv_calc(
> +xfs_calc_namespace_reservations(
>  	struct xfs_mount	*mp,
>  	struct xfs_trans_resv	*resp)
>  {
> -	/*
> -	 * The following transactions are logged in physical format and
> -	 * require a permanent reservation on space.
> -	 */
> -	resp->tr_write.tr_logres = xfs_calc_write_reservation(mp);
> -	if (xfs_sb_version_hasreflink(&mp->m_sb))
> -		resp->tr_write.tr_logcount = XFS_WRITE_LOG_COUNT_REFLINK;
> -	else
> -		resp->tr_write.tr_logcount = XFS_WRITE_LOG_COUNT;
> -	resp->tr_write.tr_logflags |= XFS_TRANS_PERM_LOG_RES;
> -
> -	resp->tr_itruncate.tr_logres = xfs_calc_itruncate_reservation(mp);
> -	if (xfs_sb_version_hasreflink(&mp->m_sb))
> -		resp->tr_itruncate.tr_logcount =
> -				XFS_ITRUNCATE_LOG_COUNT_REFLINK;
> -	else
> -		resp->tr_itruncate.tr_logcount = XFS_ITRUNCATE_LOG_COUNT;
> -	resp->tr_itruncate.tr_logflags |= XFS_TRANS_PERM_LOG_RES;
> +	ASSERT(resp->tr_attrsetm.tr_logres > 0);
>  
>  	resp->tr_rename.tr_logres = xfs_calc_rename_reservation(mp);
>  	resp->tr_rename.tr_logcount = XFS_RENAME_LOG_COUNT;
> @@ -846,15 +847,69 @@ xfs_trans_resv_calc(
>  	resp->tr_create.tr_logcount = XFS_CREATE_LOG_COUNT;
>  	resp->tr_create.tr_logflags |= XFS_TRANS_PERM_LOG_RES;
>  
> +	resp->tr_mkdir.tr_logres = xfs_calc_mkdir_reservation(mp);
> +	resp->tr_mkdir.tr_logcount = XFS_MKDIR_LOG_COUNT;
> +	resp->tr_mkdir.tr_logflags |= XFS_TRANS_PERM_LOG_RES;
> +
> +	if (!xfs_sb_version_hasparent(&mp->m_sb))
> +		return;
> +
> +	/* rename can add/remove/modify 2 parent attributes */
> +	resp->tr_rename.tr_logres += 2 * max(resp->tr_attrsetm.tr_logres,
> +					     resp->tr_attrrm.tr_logres);
> +	resp->tr_rename.tr_logcount += 2 * max(resp->tr_attrsetm.tr_logcount,
> +					       resp->tr_attrrm.tr_logcount);
> +
> +	/* create will add 1 parent attribute */
> +	resp->tr_create.tr_logres += resp->tr_attrsetm.tr_logres;
> +	resp->tr_create.tr_logcount += resp->tr_attrsetm.tr_logcount;
> +
> +	/* mkdir will add 1 parent attribute */
> +	resp->tr_mkdir.tr_logres += resp->tr_attrsetm.tr_logres;
> +	resp->tr_mkdir.tr_logcount += resp->tr_attrsetm.tr_logcount;
> +
> +	/* link will add 1 parent attribute */
> +	resp->tr_link.tr_logres += resp->tr_attrsetm.tr_logres;
> +	resp->tr_link.tr_logcount += resp->tr_attrsetm.tr_logcount;
> +
> +	/* symlink will add 1 parent attribute */
> +	resp->tr_symlink.tr_logres += resp->tr_attrsetm.tr_logres;
> +	resp->tr_symlink.tr_logcount += resp->tr_attrsetm.tr_logcount;
> +
> +	/* remove will remove 1 parent attribute */
> +	resp->tr_remove.tr_logres += resp->tr_attrrm.tr_logres;
> +	resp->tr_remove.tr_logcount = resp->tr_attrrm.tr_logcount;
> +}
> +
> +void
> +xfs_trans_resv_calc(
> +	struct xfs_mount	*mp,
> +	struct xfs_trans_resv	*resp)
> +{
> +	/*
> +	 * The following transactions are logged in physical format and
> +	 * require a permanent reservation on space.
> +	 */
> +	resp->tr_write.tr_logres = xfs_calc_write_reservation(mp);
> +	if (xfs_sb_version_hasreflink(&mp->m_sb))
> +		resp->tr_write.tr_logcount = XFS_WRITE_LOG_COUNT_REFLINK;
> +	else
> +		resp->tr_write.tr_logcount = XFS_WRITE_LOG_COUNT;
> +	resp->tr_write.tr_logflags |= XFS_TRANS_PERM_LOG_RES;
> +
> +	resp->tr_itruncate.tr_logres = xfs_calc_itruncate_reservation(mp);
> +	if (xfs_sb_version_hasreflink(&mp->m_sb))
> +		resp->tr_itruncate.tr_logcount =
> +				XFS_ITRUNCATE_LOG_COUNT_REFLINK;
> +	else
> +		resp->tr_itruncate.tr_logcount = XFS_ITRUNCATE_LOG_COUNT;
> +	resp->tr_itruncate.tr_logflags |= XFS_TRANS_PERM_LOG_RES;
> +
>  	resp->tr_create_tmpfile.tr_logres =
>  			xfs_calc_create_tmpfile_reservation(mp);
>  	resp->tr_create_tmpfile.tr_logcount = XFS_CREATE_TMPFILE_LOG_COUNT;
>  	resp->tr_create_tmpfile.tr_logflags |= XFS_TRANS_PERM_LOG_RES;
>  
> -	resp->tr_mkdir.tr_logres = xfs_calc_mkdir_reservation(mp);
> -	resp->tr_mkdir.tr_logcount = XFS_MKDIR_LOG_COUNT;
> -	resp->tr_mkdir.tr_logflags |= XFS_TRANS_PERM_LOG_RES;
> -
>  	resp->tr_ifree.tr_logres = xfs_calc_ifree_reservation(mp);
>  	resp->tr_ifree.tr_logcount = XFS_INACTIVE_LOG_COUNT;
>  	resp->tr_ifree.tr_logflags |= XFS_TRANS_PERM_LOG_RES;
> @@ -886,6 +941,8 @@ xfs_trans_resv_calc(
>  		resp->tr_qm_dqalloc.tr_logcount = XFS_WRITE_LOG_COUNT;
>  	resp->tr_qm_dqalloc.tr_logflags |= XFS_TRANS_PERM_LOG_RES;
>  
> +	xfs_calc_namespace_reservations(mp, resp);
> +
>  	/*
>  	 * The following transactions are logged in logical format with
>  	 * a default log count.
> -- 
> 2.7.4
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html