From: Vivek Goyal <vgoyal@redhat.com>
To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-nvdimm@lists.01.org, virtio-fs@redhat.com
Cc: miklos@szeredi.hu, stefanha@redhat.com, dgilbert@redhat.com,
Jan Kara <jack@suse.cz>, Christoph Hellwig <hch@infradead.org>
Subject: [PATCH v3 01/18] dax: Modify bdev_dax_pgoff() to handle NULL bdev
Date: Wed, 19 Aug 2020 18:19:39 -0400 [thread overview]
Message-ID: <20200819221956.845195-2-vgoyal@redhat.com> (raw)
In-Reply-To: <20200819221956.845195-1-vgoyal@redhat.com>
virtiofs does not have a block device but it has dax device.
Modify bdev_dax_pgoff() to be able to handle that.
If there is no bdev, that means dax offset is 0. (It can't be a partition
block device starting at an offset in dax device).
This is little hackish. There have been discussions about getting rid
of dax not supporting partitions.
https://lore.kernel.org/linux-fsdevel/20200107125159.GA15745@infradead.org/
IMHO, this path can easily break exisitng users. For example
ioctl(BLKPG_ADD_PARTITION) will start breaking on block devices
supporting DAX. Also, I personally find it very useful to be able to
partition dax devices and still be able to use DAX.
Alternatively, I tried to store offset into dax device information in iomap
interface, but that got NACKed.
https://lore.kernel.org/linux-fsdevel/20200217133117.GB20444@infradead.org/
I can't think of a good path to solve this issue properly. So to make
progress, it seems this patch is least bad option for now and I hope
we can take it.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Vishal L Verma <vishal.l.verma@intel.com>
Cc: "Weiny, Ira" <ira.weiny@intel.com>
Cc: linux-nvdimm@lists.01.org
---
drivers/dax/super.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index c82cbcb64202..505165752d8f 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -46,7 +46,8 @@ EXPORT_SYMBOL_GPL(dax_read_unlock);
int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size,
pgoff_t *pgoff)
{
- phys_addr_t phys_off = (get_start_sect(bdev) + sector) * 512;
+ sector_t start_sect = bdev ? get_start_sect(bdev) : 0;
+ phys_addr_t phys_off = (start_sect + sector) * 512;
if (pgoff)
*pgoff = PHYS_PFN(phys_off);
--
2.25.4
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next prev parent reply other threads:[~2020-08-19 22:21 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-19 22:19 [PATCH v3 00/18] virtiofs: Add DAX support Vivek Goyal
2020-08-19 22:19 ` Vivek Goyal [this message]
2020-08-19 22:19 ` [PATCH v3 02/18] dax: Create a range version of dax_layout_busy_page() Vivek Goyal
2020-08-20 12:58 ` Jan Kara
2020-08-20 14:29 ` Vivek Goyal
2020-08-19 22:19 ` [PATCH v3 03/18] virtio: Add get_shm_region method Vivek Goyal
2020-08-19 22:19 ` [PATCH v3 04/18] virtio: Implement get_shm_region for PCI transport Vivek Goyal
2020-08-19 22:19 ` [PATCH v3 05/18] virtio: Implement get_shm_region for MMIO transport Vivek Goyal
2020-08-19 22:19 ` [PATCH v3 06/18] virtiofs: Provide a helper function for virtqueue initialization Vivek Goyal
2020-08-19 22:19 ` [PATCH v3 07/18] fuse: Get rid of no_mount_options Vivek Goyal
2020-08-19 22:19 ` [PATCH v3 08/18] virtio_fs, dax: Set up virtio_fs dax_device Vivek Goyal
2020-08-19 22:19 ` [PATCH v3 09/18] fuse,virtiofs: Add a mount option to enable dax Vivek Goyal
2020-08-19 22:19 ` [PATCH v3 10/18] fuse,virtiofs: Keep a list of free dax memory ranges Vivek Goyal
2020-08-19 22:19 ` [PATCH v3 11/18] fuse: implement FUSE_INIT map_alignment field Vivek Goyal
2020-08-26 14:06 ` Miklos Szeredi
2020-08-26 15:51 ` Vivek Goyal
2020-08-26 17:34 ` Stefan Hajnoczi
2020-08-26 19:17 ` Dr. David Alan Gilbert
2020-08-26 19:26 ` Miklos Szeredi
2020-08-26 19:53 ` Vivek Goyal
2020-08-19 22:19 ` [PATCH v3 12/18] fuse: Introduce setupmapping/removemapping commands Vivek Goyal
2020-08-19 22:19 ` [PATCH v3 13/18] fuse, dax: Implement dax read/write operations Vivek Goyal
2020-08-19 22:19 ` [PATCH v3 14/18] fuse,dax: add DAX mmap support Vivek Goyal
2020-08-19 22:19 ` [PATCH v3 15/18] fuse,virtiofs: Define dax address space operations Vivek Goyal
2020-08-19 22:19 ` [PATCH v3 16/18] fuse, dax: Serialize truncate/punch_hole and dax fault path Vivek Goyal
2020-08-19 22:19 ` [PATCH v3 17/18] fuse,virtiofs: Maintain a list of busy elements Vivek Goyal
2020-08-19 22:19 ` [PATCH v3 18/18] fuse,virtiofs: Add logic to free up a memory range Vivek Goyal
2020-08-28 14:26 ` [PATCH v3 00/18] virtiofs: Add DAX support Miklos Szeredi
2020-08-28 14:39 ` Vivek Goyal
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