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Date:   Thu, 4 Apr 2019 11:56:49 +0200
From:   Adam Borowski <kilobyte@angband.pl>
To:     Pankaj Gupta <pagupta@redhat.com>
Cc:     Dave Chinner <david@fromorbit.com>,
        darrick wong <darrick.wong@oracle.com>,
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        qemu-devel@nongnu.org, linux-ext4@vger.kernel.org,
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        dan j williams <dan.j.williams@intel.com>,
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        xiaoguangrong eric <xiaoguangrong.eric@gmail.com>
Subject: Re: [PATCH v4 5/5] xfs: disable map_sync for async flush
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On Thu, Apr 04, 2019 at 02:12:30AM -0400, Pankaj Gupta wrote:
> > All this ad hoc IS_DAX conditional logic is getting pretty nasty.
> > 
> > xfs_file_mmap(
> > ....
> > {
> > 	struct inode	*inode = file_inode(filp);
> > 
> > 	if (vma->vm_flags & VM_SYNC) {
> > 		if (!IS_DAX(inode))
> > 			return -EOPNOTSUPP;
> > 		if (!dax_synchronous(xfs_find_daxdev_for_inode(inode))
> > 			return -EOPNOTSUPP;
> > 	}
> > 
> > 	file_accessed(filp);
> > 	vma->vm_ops = &xfs_file_vm_ops;
> > 	if (IS_DAX(inode))
> > 		vma->vm_flags |= VM_HUGEPAGE;
> > 	return 0;
> > }
> 
> Sure, this is better.

> > Even better, factor out all the "MAP_SYNC supported" checks into a
> > helper so that the filesystem code just doesn't have to care about
> > the details of checking for DAX+MAP_SYNC support....
> 
> o.k. Will add one common helper function for both ext4 & xfs filesystems.

Note this pending patch for Goldwyn Rodrigues' patchset for btrfs:

https://lore.kernel.org/linux-btrfs/20190328102418.5466-1-kilobyte@angband.pl/

We might want to coordinate.


Meow!
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