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From:   Ilya Dryomov <idryomov@gmail.com>
Date:   Mon, 10 Dec 2018 12:14:11 +0100
Message-ID: <CAOi1vP87vHcjmUXxzQAOuhrPrB==em9tXAocgfRsSWo5M3jtXw@mail.gmail.com>
Subject: Re: [PATCH] ceph: make 'nocopyfrom' a default mount option
To:     Luis Henriques <lhenriques@suse.com>
Cc:     "Yan, Zheng" <zyan@redhat.com>, Sage Weil <sage@redhat.com>,
        Gregory Farnum <gfarnum@redhat.com>,
        Ceph Development <ceph-devel@vger.kernel.org>,
        linux-kernel@vger.kernel.org
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On Mon, Dec 10, 2018 at 11:23 AM Luis Henriques <lhenriques@suse.com> wrote:
>
> Since we found a problem with the 'copy-from' operation after objects have
> been truncated, offloading object copies to OSDs should be discouraged
> until the issue is fixed.
>
> Thus, this patch adds the 'nocopyfrom' mount option to the default mount
> options which effectily means that remote copies won't be done in
> copy_file_range unless they are explicitly enabled at mount time.
>
> Link: https://tracker.ceph.com/issues/37378
> Signed-off-by: Luis Henriques <lhenriques@suse.com>
> ---
>  fs/ceph/super.h | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ceph/super.h b/fs/ceph/super.h
> index c005a5400f2e..79a265ba9200 100644
> --- a/fs/ceph/super.h
> +++ b/fs/ceph/super.h
> @@ -42,7 +42,9 @@
>  #define CEPH_MOUNT_OPT_NOQUOTADF       (1<<13) /* no root dir quota in statfs */
>  #define CEPH_MOUNT_OPT_NOCOPYFROM      (1<<14) /* don't use RADOS 'copy-from' op */
>
> -#define CEPH_MOUNT_OPT_DEFAULT    CEPH_MOUNT_OPT_DCACHE
> +#define CEPH_MOUNT_OPT_DEFAULT                 \
> +       (CEPH_MOUNT_OPT_DCACHE |                \
> +        CEPH_MOUNT_OPT_NOCOPYFROM)
>
>  #define ceph_set_mount_opt(fsc, opt) \
>         (fsc)->mount_options->flags |= CEPH_MOUNT_OPT_##opt;

Thanks Luis, I'll pick it up for 4.20.

                Ilya