diff mbox series

[V6,5/8] fs/xfs: Create function xfs_inode_enable_dax()

Message ID 20200407182958.568475-6-ira.weiny@intel.com (mailing list archive)
State Superseded, archived
Headers show
Series Enable per-file/per-directory DAX operations V6 | expand

Commit Message

Ira Weiny April 7, 2020, 6:29 p.m. UTC 
From: Ira Weiny <ira.weiny@intel.com>

xfs_inode_supports_dax() should reflect if the inode can support DAX not
that it is enabled for DAX.

Change the use of xfs_inode_supports_dax() to reflect only if the inode
and underlying storage support dax.

Add a new function xfs_inode_enable_dax() which reflects if the inode
should be enabled for DAX.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>

---
Changes from v5:
	Update to reflect the new tri-state mount option

Changes from v3:
	Update functions and names to be more clear
	Update commit message
	Merge with
		'fs/xfs: Clean up DAX support check'
		don't allow IS_DAX() on a directory
		use STATIC macro for static
		make xfs_inode_supports_dax() static
---
 fs/xfs/xfs_iops.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

Comments

Dave Chinner April 8, 2020, 12:05 a.m. UTC | #1 
On Tue, Apr 07, 2020 at 11:29:55AM -0700, ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com>
> 
> xfs_inode_supports_dax() should reflect if the inode can support DAX not
> that it is enabled for DAX.
> 
> Change the use of xfs_inode_supports_dax() to reflect only if the inode
> and underlying storage support dax.
> 
> Add a new function xfs_inode_enable_dax() which reflects if the inode
> should be enabled for DAX.
> 
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
....
>  
> +STATIC bool
> +xfs_inode_enable_dax(
> +	struct xfs_inode *ip)
> +{
> +	u32 dax_mode = xfs_mount_dax_mode(ip->i_mount);
> +
> +	if (dax_mode == XFS_DAX_NEVER || !xfs_inode_supports_dax(ip))
> +		return false;
> +	if (dax_mode == XFS_DAX_ALWAYS || ip->i_d.di_flags2 & XFS_DIFLAG2_DAX)
> +		return true;

These compound || statements are better written as single conditions
as they are all sequential logic checks and we can't skip over
checks.

	if (mp->m_flags & XFS_MOUNT_DAX_NEVER)
		return false;
	if (!xfs_inode_supports_dax(ip))
		return false;
	if (mp->m_flags & XFS_MOUNT_DAX_ALWAYS)
		return true;
	if (ip->i_d.di_flags2 & XFS_DIFLAG2_DAX)
		return true;
	return false;

Cheers,

Dave.
Ira Weiny April 8, 2020, 12:13 a.m. UTC | #2 
On Wed, Apr 08, 2020 at 10:05:33AM +1000, Dave Chinner wrote:
> On Tue, Apr 07, 2020 at 11:29:55AM -0700, ira.weiny@intel.com wrote:
> > From: Ira Weiny <ira.weiny@intel.com>
> > 
> > xfs_inode_supports_dax() should reflect if the inode can support DAX not
> > that it is enabled for DAX.
> > 
> > Change the use of xfs_inode_supports_dax() to reflect only if the inode
> > and underlying storage support dax.
> > 
> > Add a new function xfs_inode_enable_dax() which reflects if the inode
> > should be enabled for DAX.
> > 
> > Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> ....
> >  
> > +STATIC bool
> > +xfs_inode_enable_dax(
> > +	struct xfs_inode *ip)
> > +{
> > +	u32 dax_mode = xfs_mount_dax_mode(ip->i_mount);
> > +
> > +	if (dax_mode == XFS_DAX_NEVER || !xfs_inode_supports_dax(ip))
> > +		return false;
> > +	if (dax_mode == XFS_DAX_ALWAYS || ip->i_d.di_flags2 & XFS_DIFLAG2_DAX)
> > +		return true;
> 
> These compound || statements are better written as single conditions
> as they are all sequential logic checks and we can't skip over
> checks.
> 
> 	if (mp->m_flags & XFS_MOUNT_DAX_NEVER)
> 		return false;
> 	if (!xfs_inode_supports_dax(ip))
> 		return false;
> 	if (mp->m_flags & XFS_MOUNT_DAX_ALWAYS)
> 		return true;
> 	if (ip->i_d.di_flags2 & XFS_DIFLAG2_DAX)
> 		return true;
> 	return false;

Updated for V7

Thanks,
Ira

> 
> Cheers,
> 
> Dave.
> -- 
> Dave Chinner
> david@fromorbit.com
diff mbox series

Patch

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 1ec4a36917bd..e07f7b641226 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -1237,19 +1237,18 @@  static const struct inode_operations xfs_inline_symlink_inode_operations = {
 };
 
 /* Figure out if this file actually supports DAX. */
-static bool
+STATIC bool
 xfs_inode_supports_dax(
 	struct xfs_inode	*ip)
 {
 	struct xfs_mount	*mp = ip->i_mount;
 
 	/* Only supported on non-reflinked files. */
-	if (!S_ISREG(VFS_I(ip)->i_mode) || xfs_is_reflink_inode(ip))
+	if (xfs_is_reflink_inode(ip))
 		return false;
 
-	/* DAX mount option or DAX iflag must be set. */
-	if (xfs_mount_dax_mode(mp) != XFS_DAX_ALWAYS &&
-	    !(ip->i_d.di_flags2 & XFS_DIFLAG2_DAX))
+	/* Only supported on regular files. */
+	if (!S_ISREG(VFS_I(ip)->i_mode))
 		return false;
 
 	/* Block size must match page size */
@@ -1260,6 +1259,19 @@  xfs_inode_supports_dax(
 	return xfs_inode_buftarg(ip)->bt_daxdev != NULL;
 }
 
+STATIC bool
+xfs_inode_enable_dax(
+	struct xfs_inode *ip)
+{
+	u32 dax_mode = xfs_mount_dax_mode(ip->i_mount);
+
+	if (dax_mode == XFS_DAX_NEVER || !xfs_inode_supports_dax(ip))
+		return false;
+	if (dax_mode == XFS_DAX_ALWAYS || ip->i_d.di_flags2 & XFS_DIFLAG2_DAX)
+		return true;
+	return false;
+}
+
 STATIC void
 xfs_diflags_to_iflags(
 	struct inode		*inode,
@@ -1278,7 +1290,7 @@  xfs_diflags_to_iflags(
 		inode->i_flags |= S_SYNC;
 	if (flags & XFS_DIFLAG_NOATIME)
 		inode->i_flags |= S_NOATIME;
-	if (xfs_inode_supports_dax(ip))
+	if (xfs_inode_enable_dax(ip))
 		inode->i_flags |= S_DAX;
 }