Re: [PATCH v22 14/16] xfs: Add delattr mount option

Darrick J. Wong
2021-07-28T00:47:59Z

On Mon, Jul 26, 2021 at 11:20:51PM -0700, Allison Henderson wrote:
> This patch adds a mount option to enable delayed attributes. Eventually
> this can be removed when delayed attrs becomes permanent.
>
> Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
> ---
> fs/xfs/libxfs/xfs_attr.h | 2 +-
> fs/xfs/xfs_mount.h | 1 +
> fs/xfs/xfs_super.c | 11 ++++++++++-
> fs/xfs/xfs_xattr.c | 2 ++
> 4 files changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
> index c0c92bd3..d4e7521 100644
> --- a/fs/xfs/libxfs/xfs_attr.h
> +++ b/fs/xfs/libxfs/xfs_attr.h
> @@ -30,7 +30,7 @@ struct xfs_attr_list_context;
>
> static inline bool xfs_hasdelattr(struct xfs_mount *mp)
> {
> - return false;
> + return mp->m_flags & XFS_MOUNT_DELATTR;
> }
>
> /*
> diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
> index 66a47f5..2945868 100644
> --- a/fs/xfs/xfs_mount.h
> +++ b/fs/xfs/xfs_mount.h
> @@ -257,6 +257,7 @@ typedef struct xfs_mount {
> #define XFS_MOUNT_NOATTR2 (1ULL << 25) /* disable use of attr2 format */
> #define XFS_MOUNT_DAX_ALWAYS (1ULL << 26)
> #define XFS_MOUNT_DAX_NEVER (1ULL << 27)
> +#define XFS_MOUNT_DELATTR (1ULL << 28) /* enable delayed attributes */

So uh while we're renaming things away from "delattr", maybe this ...

LOGGED ATTRIBUTE RE PLAY

... really should become the "larp" debug-only mount option.

XFS_MOUNT_LARP

Yeah. Do it!!!

> /*
> * Max and min values for mount-option defined I/O
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 2c9e26a..39d6645 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -94,7 +94,7 @@ enum {
> Opt_filestreams, Opt_quota, Opt_noquota, Opt_usrquota, Opt_grpquota,
> Opt_prjquota, Opt_uquota, Opt_gquota, Opt_pquota,
> Opt_uqnoenforce, Opt_gqnoenforce, Opt_pqnoenforce, Opt_qnoenforce,
> - Opt_discard, Opt_nodiscard, Opt_dax, Opt_dax_enum,
> + Opt_discard, Opt_nodiscard, Opt_dax, Opt_dax_enum, Opt_delattr
> };
>
> static const struct fs_parameter_spec xfs_fs_parameters[] = {
> @@ -139,6 +139,7 @@ static const struct fs_parameter_spec xfs_fs_parameters[] = {
> fsparam_flag("nodiscard", Opt_nodiscard),
> fsparam_flag("dax", Opt_dax),
> fsparam_enum("dax", Opt_dax_enum, dax_param_enums),
> + fsparam_flag("delattr", Opt_delattr),

I think you need this line to be guarded by #ifdefs so that the mount
options parsing code will reject -o larp on non-debug kernels.

--D

> {}
> };
>
> @@ -1273,6 +1274,14 @@ xfs_fs_parse_param(
> xfs_mount_set_dax_mode(parsing_mp, result.uint_32);
> return 0;
> #endif
> +#ifdef CONFIG_XFS_DEBUG
> + case Opt_delattr:
> + xfs_warn(parsing_mp,
> + "EXPERIMENTAL logged xattrs feature in use. "
> + "Use at your own risk");
> + parsing_mp->m_flags |= XFS_MOUNT_DELATTR;
> + return 0;
> +#endif
> /* Following mount options will be removed in September 2025 */
> case Opt_ikeep:
> xfs_fs_warn_deprecated(fc, param, XFS_MOUNT_IKEEP, true);
> diff --git a/fs/xfs/xfs_xattr.c b/fs/xfs/xfs_xattr.c
> index 0d050f8..a4f97e7 100644
> --- a/fs/xfs/xfs_xattr.c
> +++ b/fs/xfs/xfs_xattr.c
> @@ -8,6 +8,8 @@
> #include "xfs_shared.h"
> #include "xfs_format.h"
> #include "xfs_log_format.h"
> +#include "xfs_trans_resv.h"
> +#include "xfs_mount.h"
> #include "xfs_da_format.h"
> #include "xfs_trans_resv.h"
> #include "xfs_mount.h"
> --
> 2.7.4
>