Re: [PATCH V11 06/11] fs/xfs: Make DAX mount option a tri-state

Darrick J. Wong
2020-04-28T20:09:11Z

On Mon, Apr 27, 2020 at 05:21:37PM -0700, ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com>
>
> As agreed upon[1]. We make the dax mount option a tri-state. '-o dax'
> continues to operate the same. We add 'always', 'never', and 'inode'
> (default).
>
> [1] https://lore.kernel.org/lkml/20200405061945.GA94792@iweiny-DESK2.sc.intel.com/
>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>

Looks good to me,
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

>
> ---
> Changes from V10:
> Move show options to xfs_info_set array
>
> Changes from V9:
> Fix indentation in xfs_mount_set_dax_mode()
> Do not report dax=inode
>
> Changes from v8:
> Move NEVER bit to 27
> Use xfs signature style
> use xfs_dax_mode enum
>
> Changes from v7:
> Change to XFS_MOUNT_DAX_NEVER
>
> Changes from v6:
> Use 2 flag bits rather than a field.
> change iflag to inode
>
> Changes from v5:
> New Patch
> ---
> fs/xfs/xfs_mount.h | 1 +
> fs/xfs/xfs_super.c | 46 ++++++++++++++++++++++++++++++++++++++++++----
> 2 files changed, 43 insertions(+), 4 deletions(-)
>
> diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
> index f6123fb0113c..37bfb50db809 100644
> --- a/fs/xfs/xfs_mount.h
> +++ b/fs/xfs/xfs_mount.h
> @@ -238,6 +238,7 @@ typedef struct xfs_mount {
> allocator */
> #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)
>
> /*
> * 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 ce169d1c7474..e80bd2c4c279 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -47,6 +47,39 @@ static struct kset *xfs_kset; /* top-level xfs sysfs dir */
> static struct xfs_kobj xfs_dbg_kobj; /* global debug sysfs attrs */
> #endif
>
> +enum xfs_dax_mode {
> + XFS_DAX_INODE = 0,
> + XFS_DAX_ALWAYS = 1,
> + XFS_DAX_NEVER = 2,
> +};
> +
> +static void
> +xfs_mount_set_dax_mode(
> + struct xfs_mount *mp,
> + enum xfs_dax_mode mode)
> +{
> + switch (mode) {
> + case XFS_DAX_INODE:
> + mp->m_flags &= ~(XFS_MOUNT_DAX_ALWAYS | XFS_MOUNT_DAX_NEVER);
> + break;
> + case XFS_DAX_ALWAYS:
> + mp->m_flags |= XFS_MOUNT_DAX_ALWAYS;
> + mp->m_flags &= ~XFS_MOUNT_DAX_NEVER;
> + break;
> + case XFS_DAX_NEVER:
> + mp->m_flags |= XFS_MOUNT_DAX_NEVER;
> + mp->m_flags &= ~XFS_MOUNT_DAX_ALWAYS;
> + break;
> + }
> +}
> +
> +static const struct constant_table dax_param_enums[] = {
> + {"inode", XFS_DAX_INODE },
> + {"always", XFS_DAX_ALWAYS },
> + {"never", XFS_DAX_NEVER },
> + {}
> +};
> +
> /*
> * Table driven mount option parser.
> */
> @@ -59,7 +92,7 @@ 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_discard, Opt_nodiscard, Opt_dax, Opt_dax_enum,
> };
>
> static const struct fs_parameter_spec xfs_fs_parameters[] = {
> @@ -103,6 +136,7 @@ static const struct fs_parameter_spec xfs_fs_parameters[] = {
> fsparam_flag("discard", Opt_discard),
> fsparam_flag("nodiscard", Opt_nodiscard),
> fsparam_flag("dax", Opt_dax),
> + fsparam_enum("dax", Opt_dax_enum, dax_param_enums),
> {}
> };
>
> @@ -129,7 +163,8 @@ xfs_fs_show_options(
> { XFS_MOUNT_GRPID, ",grpid" },
> { XFS_MOUNT_DISCARD, ",discard" },
> { XFS_MOUNT_LARGEIO, ",largeio" },
> - { XFS_MOUNT_DAX_ALWAYS, ",dax" },
> + { XFS_MOUNT_DAX_ALWAYS, ",dax=always" },
> + { XFS_MOUNT_DAX_NEVER, ",dax=never" },
> { 0, NULL }
> };
> struct xfs_mount *mp = XFS_M(root->d_sb);
> @@ -1261,7 +1296,10 @@ xfs_fc_parse_param(
> return 0;
> #ifdef CONFIG_FS_DAX
> case Opt_dax:
> - mp->m_flags |= XFS_MOUNT_DAX_ALWAYS;
> + xfs_mount_set_dax_mode(mp, XFS_DAX_ALWAYS);
> + return 0;
> + case Opt_dax_enum:
> + xfs_mount_set_dax_mode(mp, result.uint_32);
> return 0;
> #endif
> default:
> @@ -1468,7 +1506,7 @@ xfs_fc_fill_super(
> if (!rtdev_is_dax && !datadev_is_dax) {
> xfs_alert(mp,
> "DAX unsupported by block device. Turning off DAX.");
> - mp->m_flags &= ~XFS_MOUNT_DAX_ALWAYS;
> + xfs_mount_set_dax_mode(mp, XFS_DAX_NEVER);
> }
> if (xfs_sb_version_hasreflink(&mp->m_sb)) {
> xfs_alert(mp,
> --
> 2.25.1
>