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From: Ira Weiny <ira.weiny@intel.com>
To: Dave Chinner <david@fromorbit.com>
Cc: linux-kernel@vger.kernel.org,
	"Darrick J. Wong" <darrick.wong@oracle.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Christoph Hellwig <hch@lst.de>,
	"Theodore Y. Ts'o" <tytso@mit.edu>, Jan Kara <jack@suse.cz>,
	Jeff Moyer <jmoyer@redhat.com>,
	linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org,
	linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH V6 4/8] fs/xfs: Make DAX mount option a tri-state
Date: Tue, 7 Apr 2020 17:09:04 -0700	[thread overview]
Message-ID: <20200408000903.GA569068@iweiny-DESK2.sc.intel.com> (raw)
In-Reply-To: <20200407235909.GF24067@dread.disaster.area>

On Wed, Apr 08, 2020 at 09:59:09AM +1000, Dave Chinner wrote:
> On Tue, Apr 07, 2020 at 11:29:54AM -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 'iflag'
> > (default).
> > 
> > [1] https://lore.kernel.org/lkml/20200405061945.GA94792@iweiny-DESK2.sc.intel.com/
> > 
> > Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> > 
> > ---
> > Changes from v5:
> > 	New Patch
> > ---
> >  fs/xfs/xfs_iops.c  |  2 +-
> >  fs/xfs/xfs_mount.h | 26 +++++++++++++++++++++++++-
> >  fs/xfs/xfs_super.c | 34 +++++++++++++++++++++++++++++-----
> >  3 files changed, 55 insertions(+), 7 deletions(-)
> > 
> > diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> > index 81f2f93caec0..1ec4a36917bd 100644
> > --- a/fs/xfs/xfs_iops.c
> > +++ b/fs/xfs/xfs_iops.c
> > @@ -1248,7 +1248,7 @@ xfs_inode_supports_dax(
> >  		return false;
> >  
> >  	/* DAX mount option or DAX iflag must be set. */
> > -	if (!(mp->m_flags & XFS_MOUNT_DAX) &&
> > +	if (xfs_mount_dax_mode(mp) != XFS_DAX_ALWAYS &&
> >  	    !(ip->i_d.di_flags2 & XFS_DIFLAG2_DAX))
> >  		return false;
> >  
> > diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
> > index 88ab09ed29e7..ce027ee06692 100644
> > --- a/fs/xfs/xfs_mount.h
> > +++ b/fs/xfs/xfs_mount.h
> > @@ -233,7 +233,31 @@ typedef struct xfs_mount {
> >  						   allocator */
> >  #define XFS_MOUNT_NOATTR2	(1ULL << 25)	/* disable use of attr2 format */
> >  
> > -#define XFS_MOUNT_DAX		(1ULL << 62)	/* TEST ONLY! */
> > +/* DAX flag is a 2 bit field representing a tri-state for dax
> > + *      iflag, always, never
> > + * We reserve/document the 2 bits using dax field/field2
> > + */
> > +#define XFS_DAX_FIELD_MASK 0x3ULL
> > +#define XFS_DAX_FIELD_SHIFT 62
> > +#define XFS_MOUNT_DAX_FIELD	(1ULL << 62)
> > +#define XFS_MOUNT_DAX_FIELD2	(1ULL << 63)
> > +
> > +enum {
> > +	XFS_DAX_IFLAG = 0,
> > +	XFS_DAX_ALWAYS = 1,
> > +	XFS_DAX_NEVER = 2,
> > +};
> > +
> > +static inline void xfs_mount_set_dax(struct xfs_mount *mp, u32 val)
> > +{
> > +	mp->m_flags &= ~(XFS_DAX_FIELD_MASK << XFS_DAX_FIELD_SHIFT);
> > +	mp->m_flags |= ((val & XFS_DAX_FIELD_MASK) << XFS_DAX_FIELD_SHIFT);
> > +}
> > +
> > +static inline u32 xfs_mount_dax_mode(struct xfs_mount *mp)
> > +{
> > +	return (mp->m_flags >> XFS_DAX_FIELD_SHIFT) & XFS_DAX_FIELD_MASK;
> > +}
> 
> This is overly complex. Just use 2 flags:

LOL...  I was afraid someone would say that.  At first I used 2 flags with
fsparam_string, but then I realized Darrick suggested fsparam_enum:

	"It would be handy if we could have a single fsparam_enum for figuring
	out the dax mount options."

	-- https://lore.kernel.org/lkml/20200403183746.GQ80283@magnolia/

So I changed it...

Darrick?

Ira

> 
> #define XFS_MOUNT_DAX_ALWAYS	(1ULL << 26)
> #define XFS_MOUNT_DAX_NEVER	(1ULL << 27)
> 
> and if no mount flag is set, we use the inode flag....
> 
> > @@ -59,7 +66,7 @@ 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 +110,7 @@ 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 +137,6 @@ xfs_fs_show_options(
> >  		{ XFS_MOUNT_GRPID,		",grpid" },
> >  		{ XFS_MOUNT_DISCARD,		",discard" },
> >  		{ XFS_MOUNT_LARGEIO,		",largeio" },
> > -		{ XFS_MOUNT_DAX,		",dax" },
> +		{ XFS_MOUNT_DAX_ALWAYS,		",dax=always" },
> +		{ XFS_MOUNT_DAX_NEVER,		",dax=never" },
> 
> >  		{ 0, NULL }
> >  	};
> >  	struct xfs_mount	*mp = XFS_M(root->d_sb);
> > @@ -185,6 +192,20 @@ xfs_fs_show_options(
> >  	if (!(mp->m_qflags & XFS_ALL_QUOTA_ACCT))
> >  		seq_puts(m, ",noquota");
> >  
> > +	switch (xfs_mount_dax_mode(mp)) {
> > +		case XFS_DAX_IFLAG:
> > +			seq_puts(m, ",dax=iflag");
> > +			break;
> > +		case XFS_DAX_ALWAYS:
> > +			seq_puts(m, ",dax=always");
> > +			break;
> > +		case XFS_DAX_NEVER:
> > +			seq_puts(m, ",dax=never");
> > +			break;
> > +		default:
> > +			break;
> > +	}
> 
> 	if (!(mp->m_flags & (XFS_MOUNT_DAX_ALWAYS | XFS_MOUNT_DAX_NEVER))
> 		seq_puts(m, ",dax=iflag");
> 
> > +
> >  	return 0;
> >  }
> >  
> > @@ -1244,7 +1265,10 @@ xfs_fc_parse_param(
> >  		return 0;
> >  #ifdef CONFIG_FS_DAX
> >  	case Opt_dax:
> > -		mp->m_flags |= XFS_MOUNT_DAX;
> > +		xfs_mount_set_dax(mp, XFS_DAX_ALWAYS);
> > +		return 0;
> > +	case Opt_dax_enum:
> > +		xfs_mount_set_dax(mp, result.uint_32);
> >  		return 0;
> >  #endif
> >  	default:
> > @@ -1437,7 +1461,7 @@ xfs_fc_fill_super(
> >  	if (XFS_SB_VERSION_NUM(&mp->m_sb) == XFS_SB_VERSION_5)
> >  		sb->s_flags |= SB_I_VERSION;
> >  
> > -	if (mp->m_flags & XFS_MOUNT_DAX) {
> > +	if (xfs_mount_dax_mode(mp) == XFS_DAX_ALWAYS) {
> 
> 	if (mp->m_flags & XFS_MOUNT_DAX_ALWAYS) {
> 
> >  		bool rtdev_is_dax = false, datadev_is_dax;
> >  
> >  		xfs_warn(mp,
> > @@ -1451,7 +1475,7 @@ 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;
> > +			xfs_mount_set_dax(mp, XFS_DAX_NEVER);
> >  		}
> >  		if (xfs_sb_version_hasreflink(&mp->m_sb)) {
> >  			xfs_alert(mp,
> > -- 
> > 2.25.1
> > 
> > 
> 
> -- 
> Dave Chinner
> david@fromorbit.com

  reply	other threads:[~2020-04-08  0:09 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-07 18:29 [PATCH V6 0/8] Enable per-file/per-directory DAX operations V6 ira.weiny
2020-04-07 18:29 ` [PATCH V6 1/8] fs/xfs: Remove unnecessary initialization of i_rwsem ira.weiny
2020-04-07 23:46   ` Dave Chinner
2020-04-07 18:29 ` [PATCH V6 2/8] fs: Remove unneeded IS_DAX() check ira.weiny
2020-04-09  7:31   ` Christoph Hellwig
2020-04-09 14:57     ` Ira Weiny
2020-04-07 18:29 ` [PATCH V6 3/8] fs/stat: Define DAX statx attribute ira.weiny
2020-04-07 23:47   ` Dave Chinner
2020-04-07 18:29 ` [PATCH V6 4/8] fs/xfs: Make DAX mount option a tri-state ira.weiny
2020-04-07 23:59   ` Dave Chinner
2020-04-08  0:09     ` Ira Weiny [this message]
2020-04-08  0:48       ` Dave Chinner
2020-04-09 15:03         ` Ira Weiny
2020-04-07 18:29 ` [PATCH V6 5/8] fs/xfs: Create function xfs_inode_enable_dax() ira.weiny
2020-04-08  0:05   ` Dave Chinner
2020-04-08  0:13     ` Ira Weiny
2020-04-07 18:29 ` [PATCH V6 6/8] fs/xfs: Combine xfs_diflags_to_linux() and xfs_diflags_to_iflags() ira.weiny
2020-04-08  2:08   ` Dave Chinner
2020-04-08 17:09     ` Ira Weiny
2020-04-08 21:02       ` Dave Chinner
2020-04-08 21:28         ` Dan Williams
2020-04-08 22:10           ` Ira Weiny
2020-04-08 23:58           ` Dave Chinner
2020-04-09  0:22             ` Ira Weiny
2020-04-09 12:41               ` Christoph Hellwig
2020-04-09 20:49                 ` Ira Weiny
2020-04-08 22:07         ` Ira Weiny
2020-04-08 23:21           ` Dave Chinner
2020-04-09  0:12             ` Ira Weiny
2020-04-09  0:30               ` Darrick J. Wong
2020-04-09 15:29                 ` Ira Weiny
2020-04-09 16:59                   ` Darrick J. Wong
2020-04-09 17:17                     ` Jan Kara
2020-04-09 20:54                     ` Ira Weiny
2020-04-09  0:49               ` Dave Chinner
2020-04-09 12:40                 ` Christoph Hellwig
2020-04-10  0:27                   ` Dave Chinner
2020-04-07 18:29 ` [PATCH V6 7/8] fs/xfs: Change xfs_ioctl_setattr_dax_invalidate() to xfs_ioctl_dax_check() ira.weiny
2020-04-08  2:23   ` Dave Chinner
2020-04-08  9:58     ` Jan Kara
2020-04-08 21:09       ` Dave Chinner
2020-04-08 22:26         ` Ira Weiny
2020-04-08 23:48           ` Dave Chinner
2020-04-09 12:28             ` Christoph Hellwig
2020-04-08 15:37   ` Darrick J. Wong
2020-04-08 18:13     ` Ira Weiny
2020-04-16  5:39   ` [fs/xfs] 857c9841f8: xfstests.xfs.046.fail kernel test robot
2020-04-07 18:29 ` [PATCH V6 8/8] Documentation/dax: Update Usage section ira.weiny

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