Re: [PATCH v4 10/12] dax: add struct iomap based DAX PMD support

From	Christoph Hellwig <hch@lst.de>
Newsgroups	linux.kernel
Subject	Re: [PATCH v4 10/12] dax: add struct iomap based DAX PMD support
Date	2016-10-03 18:40 +0200
Message-ID	<soerv-7n1-21@gated-at.bofh.it> (permalink)
References	<smSjo-1SH-1@gated-at.bofh.it> <smSt4-1Wd-23@gated-at.bofh.it> <so9ia-48W-15@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Mon, Oct 03, 2016 at 12:59:49PM +0200, Jan Kara wrote:
> I'm not quite sure if it is OK to call ->iomap_begin() without ever calling
> ->iomap_end. Specifically the comment before iomap_apply() says:
> 
> "It is assumed that the filesystems will lock whatever resources they
> require in the iomap_begin call, and release them in the iomap_end call."
> 
> so what you do could result in unbalanced allocations / locks / whatever.
> Christoph?

Indeed.  For XFS we only rely on iomap_end for error handling at the
moment, but it is intended to be paired for locking, as cluster file
systems like gfs2 requested this.

Thread

[PATCH v4 00/12] re-enable DAX PMD support Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-09-30 00:50 +0200
  [PATCH v4 06/12] dax: consistent variable naming for DAX entries Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-09-30 01:00 +0200
    Re: [PATCH v4 06/12] dax: consistent variable naming for DAX entries Jan Kara <jack@suse.cz> - 2016-10-03 11:40 +0200
  [PATCH v4 02/12] ext4: tell DAX the size of allocation holes Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-09-30 01:00 +0200
  [PATCH v4 05/12] dax: make 'wait_table' global variable static Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-09-30 01:00 +0200
    Re: [PATCH v4 05/12] dax: make 'wait_table' global variable static Jan Kara <jack@suse.cz> - 2016-10-03 11:40 +0200
  [PATCH v4 12/12] dax: remove "depends on BROKEN" from FS_DAX_PMD Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-09-30 01:00 +0200
  [PATCH v4 09/12] dax: correct dax iomap code namespace Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-09-30 01:00 +0200
    Re: [PATCH v4 09/12] dax: correct dax iomap code namespace Christoph Hellwig <hch@lst.de> - 2016-09-30 11:00 +0200
    Re: [PATCH v4 09/12] dax: correct dax iomap code namespace Jan Kara <jack@suse.cz> - 2016-10-03 12:00 +0200
  [PATCH v4 07/12] dax: coordinate locking for offsets in PMD range Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-09-30 01:00 +0200
    Re: [PATCH v4 07/12] dax: coordinate locking for offsets in PMD range Christoph Hellwig <hch@infradead.org> - 2016-09-30 11:50 +0200
    Re: [PATCH v4 07/12] dax: coordinate locking for offsets in PMD range Jan Kara <jack@suse.cz> - 2016-10-03 12:00 +0200
      Re: [PATCH v4 07/12] dax: coordinate locking for offsets in PMD range Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-10-03 20:50 +0200
  [PATCH v4 01/12] ext4: allow DAX writeback for hole punch Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-09-30 01:00 +0200
  [PATCH v4 04/12] ext2: remove support for DAX PMD faults Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-09-30 01:00 +0200
    Re: [PATCH v4 04/12] ext2: remove support for DAX PMD faults Jan Kara <jack@suse.cz> - 2016-10-03 11:40 +0200
  [PATCH v4 03/12] dax: remove buffer_size_valid() Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-09-30 01:00 +0200
    Re: [PATCH v4 03/12] dax: remove buffer_size_valid() Christoph Hellwig <hch@lst.de> - 2016-09-30 10:50 +0200
  [PATCH v4 11/12] xfs: use struct iomap based DAX PMD fault path Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-09-30 01:00 +0200
  [PATCH v4 10/12] dax: add struct iomap based DAX PMD support Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-09-30 01:00 +0200
    Re: [PATCH v4 10/12] dax: add struct iomap based DAX PMD support Christoph Hellwig <hch@infradead.org> - 2016-09-30 12:00 +0200
      Re: [PATCH v4 10/12] dax: add struct iomap based DAX PMD support Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-10-03 23:20 +0200
    Re: [PATCH v4 10/12] dax: add struct iomap based DAX PMD support Jan Kara <jack@suse.cz> - 2016-10-03 13:10 +0200
      Re: [PATCH v4 10/12] dax: add struct iomap based DAX PMD support Christoph Hellwig <hch@lst.de> - 2016-10-03 18:40 +0200
      Re: [PATCH v4 10/12] dax: add struct iomap based DAX PMD support Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-10-03 23:10 +0200
        Re: [PATCH v4 10/12] dax: add struct iomap based DAX PMD support Jan Kara <jack@suse.cz> - 2016-10-04 08:00 +0200
          Re: [PATCH v4 10/12] dax: add struct iomap based DAX PMD support Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-10-04 17:40 +0200
            Re: [PATCH v4 10/12] dax: add struct iomap based DAX PMD support Jan Kara <jack@suse.cz> - 2016-10-05 08:00 +0200
        Re: [PATCH v4 10/12] dax: add struct iomap based DAX PMD support Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-10-06 23:40 +0200
          Re: [PATCH v4 10/12] dax: add struct iomap based DAX PMD support Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-10-07 05:00 +0200
            Re: [PATCH v4 10/12] dax: add struct iomap based DAX PMD support Jan Kara <jack@suse.cz> - 2016-10-07 09:50 +0200
  [PATCH v4 08/12] dax: remove dax_pmd_fault() Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-09-30 01:00 +0200
    Re: [PATCH v4 08/12] dax: remove dax_pmd_fault() Jan Kara <jack@suse.cz> - 2016-10-03 12:00 +0200
  Re: [PATCH v4 00/12] re-enable DAX PMD support Dave Chinner <david@fromorbit.com> - 2016-09-30 01:50 +0200
    Re: [PATCH v4 00/12] re-enable DAX PMD support Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-09-30 05:10 +0200
      Re: [PATCH v4 00/12] re-enable DAX PMD support "Darrick J. Wong" <darrick.wong@oracle.com> - 2016-09-30 06:10 +0200
        Re: [PATCH v4 00/12] re-enable DAX PMD support Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-10-03 21:00 +0200
      Re: [PATCH v4 00/12] re-enable DAX PMD support Dave Chinner <david@fromorbit.com> - 2016-09-30 08:50 +0200
        Re: [PATCH v4 00/12] re-enable DAX PMD support Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-10-03 23:20 +0200
    Re: [PATCH v4 00/12] re-enable DAX PMD support Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-10-04 01:10 +0200
  Re: [PATCH v4 00/12] re-enable DAX PMD support Christoph Hellwig <hch@infradead.org> - 2016-09-30 13:50 +0200

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