linux-kernel - Re: [Qemu-devel] [PATCH v7 6/6] xfs: disable map

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Message-ID: <7976014.27184867.1557294544901.JavaMail.zimbra@redhat.com>
Date:   Wed, 8 May 2019 01:49:04 -0400 (EDT)
From:   Pankaj Gupta <pagupta@...hat.com>
To:     "Darrick J. Wong" <darrick.wong@...cle.com>
Cc:     Dan Williams <dan.j.williams@...el.com>, Jan Kara <jack@...e.cz>,
        KVM list <kvm@...r.kernel.org>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        Jason Wang <jasowang@...hat.com>, david <david@...morbit.com>,
        Qemu Developers <qemu-devel@...gnu.org>,
        virtualization@...ts.linux-foundation.org,
        Andreas Dilger <adilger.kernel@...ger.ca>,
        Ross Zwisler <zwisler@...nel.org>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Dave Jiang <dave.jiang@...el.com>,
        linux-nvdimm <linux-nvdimm@...ts.01.org>,
        Vishal L Verma <vishal.l.verma@...el.com>,
        David Hildenbrand <david@...hat.com>,
        Matthew Wilcox <willy@...radead.org>,
        Christoph Hellwig <hch@...radead.org>,
        Linux ACPI <linux-acpi@...r.kernel.org>,
        jmoyer <jmoyer@...hat.com>,
        linux-ext4 <linux-ext4@...r.kernel.org>,
        Len Brown <lenb@...nel.org>, kilobyte@...band.pl,
        Rik van Riel <riel@...riel.com>,
        yuval shaia <yuval.shaia@...cle.com>,
        Stefan Hajnoczi <stefanha@...hat.com>,
        Paolo Bonzini <pbonzini@...hat.com>, lcapitulino@...hat.com,
        Kevin Wolf <kwolf@...hat.com>,
        Nitesh Narayan Lal <nilal@...hat.com>,
        Theodore Ts'o <tytso@....edu>,
        Xiao Guangrong <xiaoguangrong.eric@...il.com>,
        cohuck@...hat.com, "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-xfs <linux-xfs@...r.kernel.org>,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        Igor Mammedov <imammedo@...hat.com>
Subject: Re: [Qemu-devel] [PATCH v7 6/6] xfs: disable map_sync for async
 flush


> 
> On Tue, May 07, 2019 at 08:37:01AM -0700, Dan Williams wrote:
> > On Thu, Apr 25, 2019 at 10:03 PM Pankaj Gupta <pagupta@...hat.com> wrote:
> > >
> > > Dont support 'MAP_SYNC' with non-DAX files and DAX files
> > > with asynchronous dax_device. 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 <pagupta@...hat.com>
> > > ---
> > >  fs/xfs/xfs_file.c | 9 ++++++---
> > >  1 file changed, 6 insertions(+), 3 deletions(-)
> > 
> > Darrick, does this look ok to take through the nvdimm tree?
> 
> <urk> forgot about this, sorry. :/
> 
> > >
> > > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> > > index a7ceae90110e..f17652cca5ff 100644
> > > --- a/fs/xfs/xfs_file.c
> > > +++ b/fs/xfs/xfs_file.c
> > > @@ -1203,11 +1203,14 @@ xfs_file_mmap(
> > >         struct file     *filp,
> > >         struct vm_area_struct *vma)
> > >  {
> > > +       struct dax_device       *dax_dev;
> > > +
> > > +       dax_dev = xfs_find_daxdev_for_inode(file_inode(filp));
> > >         /*
> > > -        * We don't support synchronous mappings for non-DAX files. At
> > > least
> > > -        * until someone comes with a sensible use case.
> > > +        * We don't support synchronous mappings for non-DAX files and
> > > +        * for DAX files if underneath dax_device is not synchronous.
> > >          */
> > > -       if (!IS_DAX(file_inode(filp)) && (vma->vm_flags & VM_SYNC))
> > > +       if (!daxdev_mapping_supported(vma, dax_dev))
> > >                 return -EOPNOTSUPP;
> 
> LGTM, and I'm fine with it going through nvdimm.  Nothing in
> xfs-5.2-merge touches that function so it should be clean.
> 
> Reviewed-by: Darrick J. Wong <darrick.wong@...cle.com>

Thank you for the review.

Pankaj

> 
> --D
> 
> > >
> > >         file_accessed(filp);
> > > --
> > > 2.20.1
> > >
> 
>