Re: [PATCH v3 04/12] fs/xfs: Clean up DAX support check

[Dave Chinner]

On Sat, Feb 08, 2020 at 11:34:37AM -0800, ira.weiny@xxxxxxxxx wrote:
> From: Ira Weiny <ira.weiny@xxxxxxxxx>
> 
> Rather than open coding xfs_inode_supports_dax() in
> xfs_ioctl_setattr_dax_invalidate() export xfs_inode_supports_dax() and
> call it in preparation for swapping dax flags.
> 
> This also means updating xfs_inode_supports_dax() to return true for a
> directory.

That's not correct. This now means S_DAX gets set on directory inodes
because both xfs_inode_supports_dax() and the on-disk inode flag
checks return true in xfs_diflags_to_iflags(). Hence when we
instantiate a directory inode with a DAX inherit hint set on it
we'll set S_DAX on the inode and so IS_DAX() will return true for
directory inodes...

Cheers,

Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx