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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Dave Chinner <david@fromorbit.com>
Cc: Ira Weiny <ira.weiny@intel.com>, Jan Kara <jack@suse.cz>,
	Andrew Morton <akpm@linux-foundation.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Matthew Wilcox <willy@infradead.org>,
	Theodore Ts'o <tytso@mit.edu>, John Hubbard <jhubbard@nvidia.com>,
	Michal Hocko <mhocko@suse.com>,
	linux-xfs@vger.kernel.org, linux-rdma@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-nvdimm@lists.01.org, linux-ext4@vger.kernel.org,
	linux-mm@kvack.org
Subject: Re: [RFC PATCH v2 00/19] RDMA/FS DAX truncate proposal V1,000,002 ;-)
Date: Fri, 23 Aug 2019 09:04:29 -0300	[thread overview]
Message-ID: <20190823120428.GA12968@ziepe.ca> (raw)
In-Reply-To: <20190823032345.GG1119@dread.disaster.area>

On Fri, Aug 23, 2019 at 01:23:45PM +1000, Dave Chinner wrote:

> > But the fact that RDMA, and potentially others, can "pass the
> > pins" to other processes is something I spent a lot of time trying to work out.
> 
> There's nothing in file layout lease architecture that says you
> can't "pass the pins" to another process.  All the file layout lease
> requirements say is that if you are going to pass a resource for
> which the layout lease guarantees access for to another process,
> then the destination process already have a valid, active layout
> lease that covers the range of the pins being passed to it via the
> RDMA handle.

How would the kernel detect and enforce this? There are many ways to
pass a FD.

IMHO it is wrong to try and create a model where the file lease exists
independently from the kernel object relying on it. In other words the
IB MR object itself should hold a reference to the lease it relies
upon to function properly.

Then we don't have to wreck the unix FD model to fit this in.

Jason


  reply	other threads:[~2019-08-23 12:04 UTC|newest]

Thread overview: 110+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-09 22:58 [RFC PATCH v2 00/19] RDMA/FS DAX truncate proposal V1,000,002 ;-) ira.weiny
2019-08-09 22:58 ` [RFC PATCH v2 01/19] fs/locks: Export F_LAYOUT lease to user space ira.weiny
2019-08-09 23:52   ` Dave Chinner
2019-08-12 17:36     ` Ira Weiny
2019-08-14  8:05       ` Dave Chinner
2019-08-14 11:21         ` Jeff Layton
2019-08-14 11:38           ` Dave Chinner
2019-08-09 22:58 ` [RFC PATCH v2 02/19] fs/locks: Add Exclusive flag to user Layout lease ira.weiny
2019-08-14 14:15   ` Jeff Layton
2019-08-14 21:56     ` Dave Chinner
2019-08-26 10:41       ` Jeff Layton
2019-08-29 23:34         ` Ira Weiny
2019-09-04 12:52           ` Jeff Layton
2019-09-04 23:12   ` John Hubbard
2019-08-09 22:58 ` [RFC PATCH v2 03/19] mm/gup: Pass flags down to __gup_device_huge* calls ira.weiny
2019-08-09 22:58 ` [RFC PATCH v2 04/19] mm/gup: Ensure F_LAYOUT lease is held prior to GUP'ing pages ira.weiny
2019-08-09 22:58 ` [RFC PATCH v2 05/19] fs/ext4: Teach ext4 to break layout leases ira.weiny
2019-08-09 22:58 ` [RFC PATCH v2 06/19] fs/ext4: Teach dax_layout_busy_page() to operate on a sub-range ira.weiny
2019-08-23 15:18   ` Vivek Goyal
2019-08-29 18:52     ` Ira Weiny
2019-08-09 22:58 ` [RFC PATCH v2 07/19] fs/xfs: Teach xfs to use new dax_layout_busy_page() ira.weiny
2019-08-09 23:30   ` Dave Chinner
2019-08-12 18:05     ` Ira Weiny
2019-08-14  8:04       ` Dave Chinner
2019-08-09 22:58 ` [RFC PATCH v2 08/19] fs/xfs: Fail truncate if page lease can't be broken ira.weiny
2019-08-09 23:22   ` Dave Chinner
2019-08-12 18:08     ` Ira Weiny
2019-08-09 22:58 ` [RFC PATCH v2 09/19] mm/gup: Introduce vaddr_pin structure ira.weiny
2019-08-10  0:06   ` John Hubbard
2019-08-09 22:58 ` [RFC PATCH v2 10/19] mm/gup: Pass a NULL vaddr_pin through GUP fast ira.weiny
2019-08-10  0:06   ` John Hubbard
2019-08-09 22:58 ` [RFC PATCH v2 11/19] mm/gup: Pass follow_page_context further down the call stack ira.weiny
2019-08-10  0:18   ` John Hubbard
2019-08-12 19:01     ` Ira Weiny
2019-08-09 22:58 ` [RFC PATCH v2 12/19] mm/gup: Prep put_user_pages() to take an vaddr_pin struct ira.weiny
2019-08-10  0:30   ` John Hubbard
2019-08-12 20:46     ` Ira Weiny
2019-08-09 22:58 ` [RFC PATCH v2 13/19] {mm,file}: Add file_pins objects ira.weiny
2019-08-09 22:58 ` [RFC PATCH v2 14/19] fs/locks: Associate file pins while performing GUP ira.weiny
2019-08-09 22:58 ` [RFC PATCH v2 15/19] mm/gup: Introduce vaddr_pin_pages() ira.weiny
2019-08-10  0:09   ` John Hubbard
2019-08-12 21:00     ` Ira Weiny
2019-08-12 21:20       ` John Hubbard
2019-08-11 23:07   ` John Hubbard
2019-08-12 21:01     ` Ira Weiny
2019-08-12 12:28   ` Jason Gunthorpe
2019-08-12 21:48     ` Ira Weiny
2019-08-13 11:47       ` Jason Gunthorpe
2019-08-13 17:46         ` Ira Weiny
2019-08-13 17:56           ` John Hubbard
2019-08-09 22:58 ` [RFC PATCH v2 16/19] RDMA/uverbs: Add back pointer to system file object ira.weiny
2019-08-12 13:00   ` Jason Gunthorpe
2019-08-12 17:28     ` Ira Weiny
2019-08-12 17:56       ` Jason Gunthorpe
2019-08-12 21:15         ` Ira Weiny
2019-08-13 11:48           ` Jason Gunthorpe
2019-08-13 17:41             ` Ira Weiny
2019-08-13 18:00               ` Jason Gunthorpe
2019-08-13 20:38                 ` Ira Weiny
2019-08-14 12:23                   ` Jason Gunthorpe
2019-08-14 17:50                     ` Ira Weiny
2019-08-14 18:15                       ` Jason Gunthorpe
2019-09-04 22:25                     ` Ira Weiny
2019-09-11  8:19                       ` Jason Gunthorpe
2019-08-09 22:58 ` [RFC PATCH v2 17/19] RDMA/umem: Convert to vaddr_[pin|unpin]* operations ira.weiny
2019-08-09 22:58 ` [RFC PATCH v2 18/19] {mm,procfs}: Add display file_pins proc ira.weiny
2019-08-09 22:58 ` [RFC PATCH v2 19/19] mm/gup: Remove FOLL_LONGTERM DAX exclusion ira.weiny
2019-08-14 10:17 ` [RFC PATCH v2 00/19] RDMA/FS DAX truncate proposal V1,000,002 ;-) Jan Kara
2019-08-14 18:08   ` Ira Weiny
2019-08-15 13:05     ` Jan Kara
2019-08-16 19:05       ` Ira Weiny
2019-08-16 23:20         ` [RFC PATCH v2 00/19] RDMA/FS DAX truncate proposal V1,000,002 ; -) Ira Weiny
2019-08-19  6:36           ` Jan Kara
2019-08-17  2:26         ` [RFC PATCH v2 00/19] RDMA/FS DAX truncate proposal V1,000,002 ;-) Dave Chinner
2019-08-19  6:34           ` Jan Kara
2019-08-19  9:24             ` Dave Chinner
2019-08-19 12:38               ` Jason Gunthorpe
2019-08-19 21:53                 ` Ira Weiny
2019-08-20  1:12                 ` Dave Chinner
2019-08-20 11:55                   ` Jason Gunthorpe
2019-08-21 18:02                     ` Ira Weiny
2019-08-21 18:13                       ` Jason Gunthorpe
2019-08-21 18:22                         ` John Hubbard
2019-08-21 18:57                         ` Ira Weiny
2019-08-21 19:06                           ` Ira Weiny
2019-08-21 19:48                           ` Jason Gunthorpe
2019-08-21 20:44                             ` Ira Weiny
2019-08-21 23:49                               ` Jason Gunthorpe
2019-08-23  3:23                               ` Dave Chinner
2019-08-23 12:04                                 ` Jason Gunthorpe [this message]
2019-08-24  0:11                                   ` Dave Chinner
2019-08-24  5:08                                     ` Ira Weiny
2019-08-26  5:55                                       ` Dave Chinner
2019-08-29  2:02                                         ` Ira Weiny
2019-08-29  3:27                                           ` John Hubbard
2019-08-29 16:16                                             ` Ira Weiny
2019-09-02 22:26                                           ` Dave Chinner
2019-09-04 16:54                                             ` Ira Weiny
2019-08-25 19:39                                     ` Jason Gunthorpe
2019-08-24  4:49                                 ` Ira Weiny
2019-08-25 19:40                                   ` Jason Gunthorpe
2019-08-23  0:59                       ` Dave Chinner
2019-08-23 17:15                         ` Ira Weiny
2019-08-24  0:18                           ` Dave Chinner
2019-08-20  0:05               ` John Hubbard
2019-08-20  1:20                 ` Dave Chinner
2019-08-20  3:09                   ` John Hubbard
2019-08-20  3:36                     ` Dave Chinner
2019-08-21 18:43                       ` John Hubbard
2019-08-21 19:09                         ` Ira Weiny

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