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Re: [Qemu-devel] [PATCH v3 5/5] xfs: disable map_sync for virtio pmem
From: |
Darrick J. Wong |
Subject: |
Re: [Qemu-devel] [PATCH v3 5/5] xfs: disable map_sync for virtio pmem |
Date: |
Wed, 9 Jan 2019 08:26:54 -0800 |
User-agent: |
Mutt/1.9.4 (2018-02-28) |
On Wed, Jan 09, 2019 at 08:17:36PM +0530, Pankaj Gupta wrote:
> Virtio pmem provides asynchronous host page cache flush
> mechanism. we don't support 'MAP_SYNC' with virtio pmem
> and xfs.
>
> Signed-off-by: Pankaj Gupta <address@hidden>
> ---
> fs/xfs/xfs_file.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index e474250..eae4aa4 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -1190,6 +1190,14 @@ xfs_file_mmap(
> if (!IS_DAX(file_inode(filp)) && (vma->vm_flags & VM_SYNC))
> return -EOPNOTSUPP;
>
> + /* We don't support synchronous mappings with guest direct access
> + * and virtio based host page cache mechanism.
> + */
> + if (IS_DAX(file_inode(filp)) && virtio_pmem_host_cache_enabled(
Echoing what Jan said, this ought to be some sort of generic function
that tells us whether or not memory mapped from the dax device will
always still be accessible even after a crash (i.e. supports MAP_SYNC).
What if the underlying file on the host is itself on pmem and can be
MAP_SYNC'd? Shouldn't the guest be able to use MAP_SYNC as well?
--D
> + xfs_find_daxdev_for_inode(file_inode(filp))) &&
> + (vma->vm_flags & VM_SYNC))
> + return -EOPNOTSUPP;
> +
> file_accessed(filp);
> vma->vm_ops = &xfs_file_vm_ops;
> if (IS_DAX(file_inode(filp)))
> --
> 2.9.3
>
- [Qemu-devel] [PATCH v3 2/5] virtio-pmem: Add virtio pmem driver, (continued)
- [Qemu-devel] [PATCH v3 2/5] virtio-pmem: Add virtio pmem driver, Pankaj Gupta, 2019/01/09
- Re: [Qemu-devel] [PATCH v3 0/5] kvm "virtio pmem" device, Pankaj Gupta, 2019/01/09
- [Qemu-devel] [PATCH v3 0/5] kvm "virtio pmem" device, Pankaj Gupta, 2019/01/09
- [Qemu-devel] [PATCH v3 3/5] libnvdimm: add nd_region buffered dax_dev flag, Pankaj Gupta, 2019/01/09
- [Qemu-devel] [PATCH v3 4/5] ext4: disable map_sync for virtio pmem, Pankaj Gupta, 2019/01/09
- [Qemu-devel] [PATCH v3 5/5] xfs: disable map_sync for virtio pmem, Pankaj Gupta, 2019/01/09
- Re: [Qemu-devel] [PATCH v3 0/5] kvm "virtio pmem" device, Dave Chinner, 2019/01/09
- Re: [Qemu-devel] [PATCH v3 0/5] kvm "virtio pmem" device, Rik van Riel, 2019/01/10
- Re: [Qemu-devel] [PATCH v3 0/5] kvm "virtio pmem" device, Jan Kara, 2019/01/10
- Re: [Qemu-devel] [PATCH v3 0/5] kvm "virtio pmem" device, Pankaj Gupta, 2019/01/12
- Re: [Qemu-devel] [PATCH v3 0/5] kvm "virtio pmem" device, Dan Williams, 2019/01/12
- Re: [Qemu-devel] [PATCH v3 0/5] kvm "virtio pmem" device, Pankaj Gupta, 2019/01/12
- Re: [Qemu-devel] [PATCH v3 0/5] kvm "virtio pmem" device, Jan Kara, 2019/01/14
- Re: [Qemu-devel] [PATCH v3 0/5] kvm "virtio pmem" device, Pankaj Gupta, 2019/01/14
- Re: [Qemu-devel] [PATCH v3 0/5] kvm "virtio pmem" device, Pankaj Gupta, 2019/01/11