Linux-NVDIMM Archive on lore.kernel.org
 help / color / Atom feed
From: Vivek Goyal <vgoyal@redhat.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-nvdimm@lists.01.org, miklos@szeredi.hu,
	linux-kernel@vger.kernel.org, dgilbert@redhat.com,
	virtio-fs@redhat.com, stefanha@redhat.com,
	linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 01/19] dax: remove block device dependencies
Date: Wed, 28 Aug 2019 13:58:43 -0400
Message-ID: <20190828175843.GB912@redhat.com> (raw)
In-Reply-To: <20190828065809.GA27426@infradead.org>

On Tue, Aug 27, 2019 at 11:58:09PM -0700, Christoph Hellwig wrote:
> On Tue, Aug 27, 2019 at 12:38:28PM -0400, Vivek Goyal wrote:
> > > 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.
> 
> Well, then we need to find a way to get partitions for dax devices,
> as we really should not expect a block device hiding behind a dax
> dev.  That is just a weird legacy assumption - block device need to
> layer on top of the dax device optionally.
> 
> > 
> > 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.
> 
> And where would the file system get that information from?

File system knows about block device, can it just call get_start_sect()
while filling iomap->addr. And this means we don't have to have
parition information in dax device. Will something like following work?
(Just a proof of concept patch).


---
 drivers/dax/super.c |   11 +++++++++++
 fs/dax.c            |    6 +++---
 fs/ext4/inode.c     |    6 +++++-
 include/linux/dax.h |    1 +
 4 files changed, 20 insertions(+), 4 deletions(-)

Index: rhvgoyal-linux/fs/ext4/inode.c
===================================================================
--- rhvgoyal-linux.orig/fs/ext4/inode.c	2019-08-28 13:51:16.051937204 -0400
+++ rhvgoyal-linux/fs/ext4/inode.c	2019-08-28 13:51:44.453937204 -0400
@@ -3589,7 +3589,11 @@ retry:
 			WARN_ON_ONCE(1);
 			return -EIO;
 		}
-		iomap->addr = (u64)map.m_pblk << blkbits;
+		if (IS_DAX(inode))
+			iomap->addr = ((u64)map.m_pblk << blkbits) +
+				      (get_start_sect(iomap->bdev) * 512);
+		else
+			iomap->addr = (u64)map.m_pblk << blkbits;
 	}
 
 	if (map.m_flags & EXT4_MAP_NEW)
Index: rhvgoyal-linux/fs/dax.c
===================================================================
--- rhvgoyal-linux.orig/fs/dax.c	2019-08-28 13:51:16.051937204 -0400
+++ rhvgoyal-linux/fs/dax.c	2019-08-28 13:51:44.457937204 -0400
@@ -688,7 +688,7 @@ static int copy_user_dax(struct block_de
 	long rc;
 	int id;
 
-	rc = bdev_dax_pgoff(bdev, sector, size, &pgoff);
+	rc = dax_pgoff(sector, size, &pgoff);
 	if (rc)
 		return rc;
 
@@ -995,7 +995,7 @@ static int dax_iomap_pfn(struct iomap *i
 	int id, rc;
 	long length;
 
-	rc = bdev_dax_pgoff(iomap->bdev, sector, size, &pgoff);
+	rc = dax_pgoff(sector, size, &pgoff);
 	if (rc)
 		return rc;
 	id = dax_read_lock();
@@ -1137,7 +1137,7 @@ dax_iomap_actor(struct inode *inode, lof
 			break;
 		}
 
-		ret = bdev_dax_pgoff(bdev, sector, size, &pgoff);
+		ret = dax_pgoff(sector, size, &pgoff);
 		if (ret)
 			break;
 
Index: rhvgoyal-linux/drivers/dax/super.c
===================================================================
--- rhvgoyal-linux.orig/drivers/dax/super.c	2019-08-28 13:51:51.802937204 -0400
+++ rhvgoyal-linux/drivers/dax/super.c	2019-08-28 13:51:56.905937204 -0400
@@ -43,6 +43,17 @@ EXPORT_SYMBOL_GPL(dax_read_unlock);
 #ifdef CONFIG_BLOCK
 #include <linux/blkdev.h>
 
+int dax_pgoff(sector_t sector, size_t size, pgoff_t *pgoff)
+{
+	phys_addr_t phys_off = sector * 512;
+
+	if (pgoff)
+		*pgoff = PHYS_PFN(phys_off);
+	if (phys_off % PAGE_SIZE || size % PAGE_SIZE)
+		return -EINVAL;
+	return 0;
+}
+
 int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size,
 		pgoff_t *pgoff)
 {
Index: rhvgoyal-linux/include/linux/dax.h
===================================================================
--- rhvgoyal-linux.orig/include/linux/dax.h	2019-08-28 13:51:51.802937204 -0400
+++ rhvgoyal-linux/include/linux/dax.h	2019-08-28 13:51:56.908937204 -0400
@@ -111,6 +111,7 @@ static inline bool daxdev_mapping_suppor
 
 struct writeback_control;
 int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
+int dax_pgoff(sector_t, size_t, pgoff_t *pgoff);
 #if IS_ENABLED(CONFIG_FS_DAX)
 bool __bdev_dax_supported(struct block_device *bdev, int blocksize);
 static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize)
_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

  reply index

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
2019-08-28  6:58       ` Christoph Hellwig
2019-08-28 17:58         ` Vivek Goyal [this message]
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

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190828175843.GB912@redhat.com \
    --to=vgoyal@redhat.com \
    --cc=dgilbert@redhat.com \
    --cc=hch@infradead.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-nvdimm@lists.01.org \
    --cc=miklos@szeredi.hu \
    --cc=stefanha@redhat.com \
    --cc=virtio-fs@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-NVDIMM Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-nvdimm/0 linux-nvdimm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-nvdimm linux-nvdimm/ https://lore.kernel.org/linux-nvdimm \
		linux-nvdimm@lists.01.org
	public-inbox-index linux-nvdimm

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.01.lists.linux-nvdimm


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git