On Tue, Apr 14, 2020 at 08:27:18AM +0200, Christoph Hellwig wrote: > On Sun, Apr 12, 2020 at 10:40:42PM -0700, ira.weiny@xxxxxxxxx wrote: > > From: Ira Weiny <ira.weiny@xxxxxxxxx> > > [snip] > > index 81f2f93caec0..37bd15b55878 100644 > > --- a/fs/xfs/xfs_iops.c > > +++ b/fs/xfs/xfs_iops.c > > @@ -1244,12 +1244,11 @@ xfs_inode_supports_dax( > > 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 (!(mp->m_flags & XFS_MOUNT_DAX) && > > - !(ip->i_d.di_flags2 & XFS_DIFLAG2_DAX)) > > + /* Only supported on regular files. */ > > + if (!S_ISREG(VFS_I(ip)->i_mode)) > > return false; > > To me it would make sense to check S_ISREG before reflink, as it seems > more logical. Done. > > > +#ifdef CONFIG_FS_DAX > > +static bool > > +xfs_inode_enable_dax( > > + struct xfs_inode *ip) > > +{ > > + if (ip->i_mount->m_flags & XFS_MOUNT_NODAX) > > + return false; > > + if (!xfs_inode_supports_dax(ip)) > > + return false; > > + if (ip->i_mount->m_flags & XFS_MOUNT_DAX) > > + return true; > > + if (ip->i_d.di_flags2 & XFS_DIFLAG2_DAX) > > + return true; > > + return false; > > +} > > +#else /* !CONFIG_FS_DAX */ > > +static bool > > +xfs_inode_enable_dax( > > + struct xfs_inode *ip) > > +{ > > + return false; > > +} > > +#endif /* CONFIG_FS_DAX */ > > Just throw in a > > if (!IS_ENABLED(CONFIG_FS_DAX)) > return false; > > as the first statement of the full version and avoid the stub entirely? Sure, less code that way. Done. Ira