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From:   David Wysochanski <dwysocha@redhat.com>
Date:   Thu, 30 Jul 2020 15:23:12 -0400
Message-ID: <CALF+zOnYLbibbYxvbyUJFJQ+NtcreuAvFkZYr9h3_qQswbMxRw@mail.gmail.com>
Subject: Re: [Linux-cachefs] [RFC PATCH v2 13/14] NFS: Call
 fscache_resize_cookie() when inode size changes due to setattr
To:     Jeff Layton <jlayton@redhat.com>
Cc:     Trond Myklebust <trondmy@hammerspace.com>,
        Anna Schumaker <anna.schumaker@netapp.com>,
        linux-nfs <linux-nfs@vger.kernel.org>, linux-cachefs@redhat.com
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On Thu, Jul 30, 2020 at 2:39 PM Jeff Layton <jlayton@redhat.com> wrote:
>
> On Wed, 2020-07-29 at 10:12 -0400, Dave Wysochanski wrote:
> > Handle truncate / setattr when fscache is enabled by calling
> > fscache_resize_cookie().
> >
> > Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
> > ---
> >  fs/nfs/inode.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
> > index 45067303348c..6b814246d07d 100644
> > --- a/fs/nfs/inode.c
> > +++ b/fs/nfs/inode.c
> > @@ -667,6 +667,7 @@ static int nfs_vmtruncate(struct inode * inode, loff_t offset)
> >       spin_unlock(&inode->i_lock);
> >       truncate_pagecache(inode, offset);
> >       spin_lock(&inode->i_lock);
> > +     fscache_resize_cookie(nfs_i_fscache(inode), i_size_read(inode));
> >  out:
> >       return err;
> >  }
>
> truncate can happen even when you have no open file descriptors on the
> file and therefore w/o the cookie being "used". In the ceph vmtruncate
> handling code, I do an explicit use/unuse around this call. Do you need
> to do the same here?
> --
> Jeff Layton <jlayton@redhat.com>
>

Actually I think the case you mention is covered by a patch that I've just
added today on top of my v2 posting.
This was the result of looking deeper into a few xfstest failures with
NFSv4.2.  I think this covers the truncate without a file open:

commit 91d6922df9390ca1c090911be6e5c5ab1a79ea83
Author: Dave Wysochanski <dwysocha@redhat.com>
Date:   Thu Jul 30 12:33:40 2020 -0400

    NFS: Call fscache_invalidate() from nfs_invalidate_mapping()

    Be sure to invalidate fscache cookie for any call to
    nfs_invalidate_mapping().

    This patch fixes the following xfstests on NFS4.x:
      generic/240
    as well as fixes the following xfstests on NFSv4.2:
      generic/029 generic/030

    Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 6b814246d07d..62243ec05917 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1233,6 +1233,7 @@ static int nfs_invalidate_mapping(struct inode
*inode, struct address_space *map
        struct nfs_inode *nfsi = NFS_I(inode);
        int ret;

+       nfs_fscache_invalidate(inode, 0);
        if (mapping->nrpages != 0) {
                if (S_ISREG(inode->i_mode)) {
                        ret = nfs_sync_mapping(mapping);