Re: [PATCH 4/6] xfs: Set BH_New for allocated DAX blocks in __xfs_get_blocks()

2016-10-03 Thread Christoph Hellwig 
On Mon, Oct 03, 2016 at 04:42:46PM +0200, Jan Kara wrote:
> Ah, you are right. After reading the code again this patch is not needed
> anymore because xfs_file_iomap_begin() returns IOMAP_F_NEW whenever we
> allocated block regardless whether it was zeroed-out or not. But if I get it
> right, all the IS_DAX checks in __xfs_get_blocks() can be dropped now, cannot
> they?

Right now the code is required to keep the pmd_fault handler (which
is always disabled though) compiling.  Once that one is gone the
DAX code in __xfs_get_blocks can be removed.  In fact Ross sent a
patch to do just that as part of his PMD fault rework.
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Re: [PATCH 4/6] xfs: Set BH_New for allocated DAX blocks in __xfs_get_blocks()

2016-10-03 Thread Jan Kara 
On Tue 27-09-16 19:13:50, Christoph Hellwig wrote:
> On Tue, Sep 27, 2016 at 07:17:07PM +0200, Jan Kara wrote:
> > OK, the changelog is stale but I actually took care to integrate this with
> > your iomap patches and for the new invalidation code in iomap_dax_actor()
> > to work we need this additional information...
> 
> It's not just the changelogs (which will need updates on more than this
> patch), but also the content.  We're not using get_blocks for DAX
> anymore, so this patch should not be needed anymore.

Ah, you are right. After reading the code again this patch is not needed
anymore because xfs_file_iomap_begin() returns IOMAP_F_NEW whenever we
allocated block regardless whether it was zeroed-out or not. But if I get it
right, all the IS_DAX checks in __xfs_get_blocks() can be dropped now, cannot
they?

Honza
-- 
Jan Kara 
SUSE Labs, CR
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Re: [PATCH 4/6] xfs: Set BH_New for allocated DAX blocks in __xfs_get_blocks()

2016-09-27 Thread Christoph Hellwig 
On Tue, Sep 27, 2016 at 07:17:07PM +0200, Jan Kara wrote:
> OK, the changelog is stale but I actually took care to integrate this with
> your iomap patches and for the new invalidation code in iomap_dax_actor()
> to work we need this additional information...

It's not just the changelogs (which will need updates on more than this
patch), but also the content.  We're not using get_blocks for DAX
anymore, so this patch should not be needed anymore.
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Re: [PATCH 4/6] xfs: Set BH_New for allocated DAX blocks in __xfs_get_blocks()

2016-09-27 Thread Jan Kara 
On Tue 27-09-16 10:01:18, Christoph Hellwig wrote:
> On Tue, Sep 27, 2016 at 06:43:33PM +0200, Jan Kara wrote:
> > So far we did not set BH_New for newly allocated blocks for DAX inodes
> > in __xfs_get_blocks() because we wanted to avoid zeroing done in generic
> > DAX code which was racy. Now the zeroing is gone so we can remove this
> > workaround and return BH_New for newly allocated blocks. DAX will use this
> > information to properly update mappings of the file.
> 
> __xfs_get_blocks isn't used by the DAX code any more.
> xfs_file_iomap_begin should already be doing the right thing for now.

OK, the changelog is stale but I actually took care to integrate this with
your iomap patches and for the new invalidation code in iomap_dax_actor()
to work we need this additional information...

Honza
-- 
Jan Kara 
SUSE Labs, CR
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Re: [PATCH 4/6] xfs: Set BH_New for allocated DAX blocks in __xfs_get_blocks()

2016-09-27 Thread Christoph Hellwig 
On Tue, Sep 27, 2016 at 06:43:33PM +0200, Jan Kara wrote:
> So far we did not set BH_New for newly allocated blocks for DAX inodes
> in __xfs_get_blocks() because we wanted to avoid zeroing done in generic
> DAX code which was racy. Now the zeroing is gone so we can remove this
> workaround and return BH_New for newly allocated blocks. DAX will use this
> information to properly update mappings of the file.

__xfs_get_blocks isn't used by the DAX code any more.
xfs_file_iomap_begin should already be doing the right thing for now.
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