From: Vivek Goyal <vgoyal@redhat.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-nvdimm@lists.01.org, virtio-fs@redhat.com,
miklos@szeredi.hu, stefanha@redhat.com, dgilbert@redhat.com,
Dan Williams <dan.j.williams@intel.com>
Subject: Re: [PATCH 01/19] dax: remove block device dependencies
Date: Tue, 27 Aug 2019 12:38:28 -0400 [thread overview]
Message-ID: <20190827163828.GA6859@redhat.com> (raw)
In-Reply-To: <20190826115152.GA21051@infradead.org>
On Mon, Aug 26, 2019 at 04:51:52AM -0700, Christoph Hellwig wrote:
> On Wed, Aug 21, 2019 at 01:57:02PM -0400, Vivek Goyal wrote:
> > From: Stefan Hajnoczi <stefanha@redhat.com>
> >
> > Although struct dax_device itself is not tied to a block device, some
> > DAX code assumes there is a block device. Make block devices optional
> > by allowing bdev to be NULL in commonly used DAX APIs.
> >
> > When there is no block device:
> > * Skip the partition offset calculation in bdev_dax_pgoff()
> > * Skip the blkdev_issue_zeroout() optimization
> >
> > Note that more block device assumptions remain but I haven't reach those
> > code paths yet.
>
> I think this should be split into two patches.
Hi Christoph,
Ok, will split in two patches. In fact, I think will completley drop
the second change right now as I think we might not be hitting that
path yet.
> For bdev_dax_pgoff
> I'd much rather have the partition offset if there is on in the daxdev
> somehow so that we can get rid of the block device entirely.
IIUC, there is one block_device per partition while there is only one
dax_device for the whole disk. So we can't directly move bdev logical
offset into dax_device.
We probably could put this in "iomap" and leave it to filesystems to
report offset into dax_dev in iomap that way dax generic code does not
have to deal with it. But that probably will be a bigger change.
Did I misunderstand your suggestion.
>
> Similarly for dax_range_is_aligned I'd rather have a pure dax way
> to offload zeroing rather than this bdev hack.
Following commig introduced the change to write zeros through block
device path.
commit 4b0228fa1d753f77fe0e6cf4c41398ec77dfbd2a
Author: Vishal Verma <vishal.l.verma@intel.com>
Date: Thu Apr 21 15:13:46 2016 -0400
dax: for truncate/hole-punch, do zeroing through the driver if possible
IIUC, they are doing it so that they can clear gendisk->badblocks list.
So even if there is pure dax way to do it, there will have to some
involvment of block layer to clear gendisk->badblocks list.
I am not sure I fully understand your suggestion. But I am hoping its
not a must for these changes to make a progress. For now, I will drop
change to dax_range_is_aligned().
Thanks
Vivek
next prev parent reply other threads:[~2019-08-27 16:38 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-21 17:57 [PATCH v3 00/19][RFC] virtio-fs: Enable DAX support Vivek Goyal
2019-08-21 17:57 ` [PATCH 01/19] dax: remove block device dependencies Vivek Goyal
2019-08-26 11:51 ` Christoph Hellwig
2019-08-27 16:38 ` Vivek Goyal [this message]
2019-08-28 6:58 ` Christoph Hellwig
2019-08-28 17:58 ` Vivek Goyal
2019-08-28 22:53 ` Dave Chinner
2019-08-29 0:04 ` Dan Williams
2019-08-29 9:32 ` Christoph Hellwig
2019-12-16 18:10 ` Vivek Goyal
2020-01-07 12:51 ` Christoph Hellwig
2020-01-07 14:22 ` Dan Williams
2020-01-07 17:07 ` Darrick J. Wong
2020-01-07 17:29 ` Dan Williams
2020-01-07 18:01 ` Vivek Goyal
2020-01-07 18:07 ` Dan Williams
2020-01-07 18:33 ` Vivek Goyal
2020-01-07 18:49 ` Dan Williams
2020-01-07 19:02 ` Darrick J. Wong
2020-01-07 19:46 ` Dan Williams
2020-01-07 23:38 ` Dan Williams
2020-01-09 11:24 ` Jan Kara
2020-01-09 20:03 ` Dan Williams
2020-01-10 12:36 ` Christoph Hellwig
2020-01-14 20:31 ` Vivek Goyal
2020-01-14 20:39 ` Dan Williams
2020-01-14 21:28 ` Vivek Goyal
2020-01-14 22:23 ` Dan Williams
2020-01-15 19:56 ` Vivek Goyal
2020-01-15 20:17 ` Dan Williams
2020-01-15 21:08 ` Jeff Moyer
2020-01-16 18:09 ` Dan Williams
2020-01-16 18:39 ` Vivek Goyal
2020-01-16 19:09 ` Dan Williams
2020-01-16 19:23 ` Vivek Goyal
2020-02-11 17:33 ` Vivek Goyal
2020-01-15 9:03 ` Jan Kara
2019-08-21 17:57 ` [PATCH 02/19] dax: Pass dax_dev to dax_writeback_mapping_range() Vivek Goyal
2019-08-26 11:53 ` Christoph Hellwig
2019-08-26 20:33 ` Vivek Goyal
2019-08-26 20:58 ` Vivek Goyal
2019-08-26 21:33 ` Dan Williams
2019-08-28 6:58 ` Christoph Hellwig
2020-01-03 14:12 ` Vivek Goyal
2020-01-03 18:12 ` Dan Williams
2020-01-03 18:18 ` Dan Williams
2020-01-03 18:33 ` Vivek Goyal
2020-01-03 19:30 ` Dan Williams
2020-01-03 18:43 ` Vivek Goyal
2019-08-27 13:45 ` Jan Kara
2019-08-21 17:57 ` [PATCH 03/19] virtio: Add get_shm_region method Vivek Goyal
2019-08-21 17:57 ` [PATCH 04/19] virtio: Implement get_shm_region for PCI transport Vivek Goyal
2019-08-26 1:43 ` [Virtio-fs] " piaojun
2019-08-26 13:06 ` Vivek Goyal
2019-08-27 9:41 ` piaojun
2019-08-27 8:34 ` Cornelia Huck
2019-08-27 8:46 ` Cornelia Huck
2019-08-27 11:53 ` Vivek Goyal
2019-08-21 17:57 ` [PATCH 05/19] virtio: Implement get_shm_region for MMIO transport Vivek Goyal
2019-08-27 8:39 ` Cornelia Huck
2019-08-27 11:54 ` Vivek Goyal
2019-08-21 17:57 ` [PATCH 06/19] fuse, dax: add fuse_conn->dax_dev field Vivek Goyal
2019-08-21 17:57 ` [PATCH 07/19] virtio_fs, dax: Set up virtio_fs dax_device Vivek Goyal
2019-08-21 17:57 ` [PATCH 08/19] fuse: Keep a list of free dax memory ranges Vivek Goyal
2019-08-21 17:57 ` [PATCH 09/19] fuse: implement FUSE_INIT map_alignment field Vivek Goyal
2019-08-21 17:57 ` [PATCH 10/19] fuse: Introduce setupmapping/removemapping commands Vivek Goyal
2019-08-21 17:57 ` [PATCH 11/19] fuse, dax: Implement dax read/write operations Vivek Goyal
2019-08-21 19:49 ` Liu Bo
2019-08-22 12:59 ` Vivek Goyal
2019-08-21 17:57 ` [PATCH 12/19] fuse, dax: add DAX mmap support Vivek Goyal
2019-08-21 17:57 ` [PATCH 13/19] fuse: Define dax address space operations Vivek Goyal
2019-08-21 17:57 ` [PATCH 14/19] fuse, dax: Take ->i_mmap_sem lock during dax page fault Vivek Goyal
2019-08-21 17:57 ` [PATCH 15/19] fuse: Maintain a list of busy elements Vivek Goyal
2019-08-21 17:57 ` [PATCH 16/19] dax: Create a range version of dax_layout_busy_page() Vivek Goyal
2019-08-21 17:57 ` [PATCH 17/19] fuse: Add logic to free up a memory range Vivek Goyal
2019-08-21 17:57 ` [PATCH 18/19] fuse: Release file in process context Vivek Goyal
2019-08-21 17:57 ` [PATCH 19/19] fuse: Take inode lock for dax inode truncation Vivek Goyal
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