diff mbox

[v2,3/3] xfs: Add alignment check for DAX mount

Message ID 1462214578-27122-4-git-send-email-toshi.kani@hpe.com (mailing list archive)
State New, archived
Headers show

Commit Message

Kani, Toshi May 2, 2016, 6:42 p.m. UTC 
When a partition is not aligned by 4KB, mount -o dax succeeds,
but any read/write access to the filesystem fails, except for
metadata update.

Call bdev_direct_access to check the alignment when -o dax is
specified.

Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Boaz Harrosh <boaz@plexistor.com>
---
 fs/xfs/xfs_super.c |   23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

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Comments

Ross Zwisler May 2, 2016, 7:50 p.m. UTC | #1 
On Mon, May 02, 2016 at 12:42:58PM -0600, Toshi Kani wrote:
> When a partition is not aligned by 4KB, mount -o dax succeeds,
> but any read/write access to the filesystem fails, except for
> metadata update.
> 
> Call bdev_direct_access to check the alignment when -o dax is
> specified.
> 
> Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
> Cc: Dave Chinner <david@fromorbit.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
> Cc: Christoph Hellwig <hch@infradead.org>
> Cc: Boaz Harrosh <boaz@plexistor.com>
> ---
>  fs/xfs/xfs_super.c |   23 +++++++++++++++++++----
>  1 file changed, 19 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 187e14b..b7ee323 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -1557,15 +1557,30 @@ xfs_fs_fill_super(
>  		sb->s_flags |= MS_I_VERSION;
>  
>  	if (mp->m_flags & XFS_MOUNT_DAX) {
> +		struct blk_dax_ctl dax = {
> +			.sector = 0,
> +			.size = PAGE_SIZE,
> +		};
>  		xfs_warn(mp,
> -	"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
> +		"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
>  		if (sb->s_blocksize != PAGE_SIZE) {
>  			xfs_alert(mp,
>  		"Filesystem block size invalid for DAX Turning DAX off.");
>  			mp->m_flags &= ~XFS_MOUNT_DAX;
> -		} else if (!sb->s_bdev->bd_disk->fops->direct_access) {
> -			xfs_alert(mp,
> -		"Block device does not support DAX Turning DAX off.");
> +		} else if ((error = bdev_direct_access(sb->s_bdev, &dax)) < 0) {
> +			switch (error) {
> +			case -EOPNOTSUPP:
> +				xfs_alert(mp,
> +			"Block device does not support DAX Turning DAX off.");

Since you're already in here editing all the strings, can you add a period to
make it more readable?   Applies to all strings.

> +			"Block device does not support DAX. Turning DAX off.");
							  ^

> +				break;
> +			case -EINVAL:
> +				xfs_alert(mp,
> +			"Partition alignment invalid for DAX Turning DAX off.");
> +				break;
> +			default:
> +				xfs_alert(mp,
> +			"DAX access failed (%d) DAX Turning DAX off.", error);

I DAX think you might DAX have too many DAXes in here. :)

> +			}
>  			mp->m_flags &= ~XFS_MOUNT_DAX;
>  		}
>  	}

Other than the nit-picking about the strings, this seems fine.

You can add this for the series:
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
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Kani, Toshi May 2, 2016, 7:54 p.m. UTC | #2 
On Mon, 2016-05-02 at 13:50 -0600, Ross Zwisler wrote:
> On Mon, May 02, 2016 at 12:42:58PM -0600, Toshi Kani wrote:
 :
> >  		xfs_warn(mp,
> > -	"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
> > +		"DAX enabled. Warning: EXPERIMENTAL, use at your own
> > risk");
> >  		if (sb->s_blocksize != PAGE_SIZE) {
> >  			xfs_alert(mp,
> >  		"Filesystem block size invalid for DAX Turning DAX
> > off.");
> >  			mp->m_flags &= ~XFS_MOUNT_DAX;
> > -		} else if (!sb->s_bdev->bd_disk->fops->direct_access)
> > {
> > -			xfs_alert(mp,
> > -		"Block device does not support DAX Turning DAX off.");
> > +		} else if ((error = bdev_direct_access(sb->s_bdev,
> > &dax)) < 0) {
> > +			switch (error) {
> > +			case -EOPNOTSUPP:
> > +				xfs_alert(mp,
> > +			"Block device does not support DAX Turning DAX
> > off.");
>
> Since you're already in here editing all the strings, can you add a
> period to make it more readable?   Applies to all strings.

Right. Will do.

> > 
> > +			"Block device does not support DAX. Turning
> > DAX off.");
> 							  ^
> 
> > 
> > +				break;
> > +			case -EINVAL:
> > +				xfs_alert(mp,
> > +			"Partition alignment invalid for DAX Turning
> > DAX off.");
> > +				break;
> > +			default:
> > +				xfs_alert(mp,
> > +			"DAX access failed (%d) DAX Turning DAX off.",
> > error);
>
> I DAX think you might DAX have too many DAXes in here. :)

Oops! :)

> > 
> > +			}
> >  			mp->m_flags &= ~XFS_MOUNT_DAX;
> >  		}
> >  	}
>
> Other than the nit-picking about the strings, this seems fine.
> 
> You can add this for the series:
> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>

Thanks!
-Toshi
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Dave Chinner May 4, 2016, 11:18 p.m. UTC | #3 
On Mon, May 02, 2016 at 12:42:58PM -0600, Toshi Kani wrote:
> When a partition is not aligned by 4KB, mount -o dax succeeds,
> but any read/write access to the filesystem fails, except for
> metadata update.
> 
> Call bdev_direct_access to check the alignment when -o dax is
> specified.
> 
> Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
> Cc: Dave Chinner <david@fromorbit.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
> Cc: Christoph Hellwig <hch@infradead.org>
> Cc: Boaz Harrosh <boaz@plexistor.com>
> ---
>  fs/xfs/xfs_super.c |   23 +++++++++++++++++++----
>  1 file changed, 19 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 187e14b..b7ee323 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -1557,15 +1557,30 @@ xfs_fs_fill_super(
>  		sb->s_flags |= MS_I_VERSION;
>  
>  	if (mp->m_flags & XFS_MOUNT_DAX) {
> +		struct blk_dax_ctl dax = {
> +			.sector = 0,
> +			.size = PAGE_SIZE,
> +		};
>  		xfs_warn(mp,
> -	"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
> +		"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
>  		if (sb->s_blocksize != PAGE_SIZE) {
>  			xfs_alert(mp,
>  		"Filesystem block size invalid for DAX Turning DAX off.");
>  			mp->m_flags &= ~XFS_MOUNT_DAX;
> -		} else if (!sb->s_bdev->bd_disk->fops->direct_access) {
> -			xfs_alert(mp,
> -		"Block device does not support DAX Turning DAX off.");
> +		} else if ((error = bdev_direct_access(sb->s_bdev, &dax)) < 0) {
> +			switch (error) {
> +			case -EOPNOTSUPP:
> +				xfs_alert(mp,
> +			"Block device does not support DAX Turning DAX off.");
> +				break;
> +			case -EINVAL:
> +				xfs_alert(mp,
> +			"Partition alignment invalid for DAX Turning DAX off.");
> +				break;
> +			default:
> +				xfs_alert(mp,
> +			"DAX access failed (%d) DAX Turning DAX off.", error);
> +			}

Please write a helper along the lines of:

	error = blkdev_supports_dax(sb->s_bdev, sb->s_blocksize);

and encapsulate all this, including the specific error messages in the
helper (i.e. "Block device %s does not support DAX."). Then the rest
of the filesystem code looks something like this:

	if (mp->m_flags & XFS_MOUNT_DAX) {
		error = blkdev_supports_dax(sb->s_bdev, sb->s_blocksize);
		if (error) {
			xfs_alert(mp,
		"DAX unsupported by block device. Turning off DAX.");
			mp->m_flags &= ~XFS_MOUNT_DAX;
		}
	}

And each filesystem can choose to do what it wants with the error
without having to care exactly why DAX is not supported.

Cheers,

Dave.
Kani, Toshi May 4, 2016, 11:41 p.m. UTC | #4 
On Thu, 2016-05-05 at 09:18 +1000, Dave Chinner wrote:
> On Mon, May 02, 2016 at 12:42:58PM -0600, Toshi Kani wrote:
> > 
:
> Please write a helper along the lines of:
> 
> 	error = blkdev_supports_dax(sb->s_bdev, sb->s_blocksize);
> 
> and encapsulate all this, including the specific error messages in the
> helper (i.e. "Block device %s does not support DAX."). Then the rest
> of the filesystem code looks something like this:
> 
> 	if (mp->m_flags & XFS_MOUNT_DAX) {
> 		error = blkdev_supports_dax(sb->s_bdev, sb->s_blocksize);
> 		if (error) {
> 			xfs_alert(mp,
> 		"DAX unsupported by block device. Turning off DAX.");
> 			mp->m_flags &= ~XFS_MOUNT_DAX;
> 		}
> 	}
> 
> And each filesystem can choose to do what it wants with the error
> without having to care exactly why DAX is not supported.

Yes, I had this change in mind and was wondering if you are OK with it
since I am incline to keep the ext2/4 message style as majority rule. :)
https://lkml.org/lkml/2016/5/3/543

Assuming that's OK, I will make this change.

Thanks!
-Toshi

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Jan Kara May 5, 2016, 8:03 a.m. UTC | #5 
On Wed 04-05-16 17:41:26, Toshi Kani wrote:
> On Thu, 2016-05-05 at 09:18 +1000, Dave Chinner wrote:
> > On Mon, May 02, 2016 at 12:42:58PM -0600, Toshi Kani wrote:
> > > 
> :
> > Please write a helper along the lines of:
> > 
> > 	error = blkdev_supports_dax(sb->s_bdev, sb->s_blocksize);
> > 
> > and encapsulate all this, including the specific error messages in the
> > helper (i.e. "Block device %s does not support DAX."). Then the rest
> > of the filesystem code looks something like this:
> > 
> > 	if (mp->m_flags & XFS_MOUNT_DAX) {
> > 		error = blkdev_supports_dax(sb->s_bdev, sb->s_blocksize);
> > 		if (error) {
> > 			xfs_alert(mp,
> > 		"DAX unsupported by block device. Turning off DAX.");
> > 			mp->m_flags &= ~XFS_MOUNT_DAX;
> > 		}
> > 	}
> > 
> > And each filesystem can choose to do what it wants with the error
> > without having to care exactly why DAX is not supported.
> 
> Yes, I had this change in mind and was wondering if you are OK with it
> since I am incline to keep the ext2/4 message style as majority rule. :)
> https://lkml.org/lkml/2016/5/3/543
> 
> Assuming that's OK, I will make this change.

Yeah, just send me ext2 changes on top of your v2 and I can pull it to my
tree.


								Honza
diff mbox

Patch

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 187e14b..b7ee323 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1557,15 +1557,30 @@  xfs_fs_fill_super(
 		sb->s_flags |= MS_I_VERSION;
 
 	if (mp->m_flags & XFS_MOUNT_DAX) {
+		struct blk_dax_ctl dax = {
+			.sector = 0,
+			.size = PAGE_SIZE,
+		};
 		xfs_warn(mp,
-	"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
+		"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
 		if (sb->s_blocksize != PAGE_SIZE) {
 			xfs_alert(mp,
 		"Filesystem block size invalid for DAX Turning DAX off.");
 			mp->m_flags &= ~XFS_MOUNT_DAX;
-		} else if (!sb->s_bdev->bd_disk->fops->direct_access) {
-			xfs_alert(mp,
-		"Block device does not support DAX Turning DAX off.");
+		} else if ((error = bdev_direct_access(sb->s_bdev, &dax)) < 0) {
+			switch (error) {
+			case -EOPNOTSUPP:
+				xfs_alert(mp,
+			"Block device does not support DAX Turning DAX off.");
+				break;
+			case -EINVAL:
+				xfs_alert(mp,
+			"Partition alignment invalid for DAX Turning DAX off.");
+				break;
+			default:
+				xfs_alert(mp,
+			"DAX access failed (%d) DAX Turning DAX off.", error);
+			}
 			mp->m_flags &= ~XFS_MOUNT_DAX;
 		}
 	}