linux-kernel - Re: [PATCH] ceph: add destination file data sync before doing any remote copy

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Message-ID: <CAAM7YA=k5h-PdqACkmWGtiu+5cpRki0FWyMW4ukyzSgdMKGa6w@mail.gmail.com>
Date:   Tue, 23 Oct 2018 19:38:24 +0800
From:   "Yan, Zheng" <ukernel@...il.com>
To:     Luis Henriques <lhenriques@...e.com>
Cc:     Zheng Yan <zyan@...hat.com>, Sage Weil <sage@...hat.com>,
        Ilya Dryomov <idryomov@...il.com>,
        ceph-devel <ceph-devel@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ceph: add destination file data sync before doing any
 remote copy

On Tue, Oct 23, 2018 at 5:08 PM Luis Henriques <lhenriques@...e.com> wrote:
>
> If we try to copy into a file that was just written, any data that is remote
> copied will be overwritten by our buffered writes once they are flushed.  When
> this happens, the call to invalidate_inode_pages2_range will also return a
> -EBUSY error.
>
> This patch fixes this by also sync'ing the destination file before starting any
> copy.
>
> Signed-off-by: Luis Henriques <lhenriques@...e.com>
> ---
>  fs/ceph/file.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index f788496fafcc..b4607baa8969 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -1932,10 +1932,17 @@ static ssize_t ceph_copy_file_range(struct file *src_file, loff_t src_off,
>         if (!prealloc_cf)
>                 return -ENOMEM;
>
> -       /* Start by sync'ing the source file */
> +       /* Start by sync'ing the source and destination files */
>         ret = file_write_and_wait_range(src_file, src_off, (src_off + len));
> -       if (ret < 0)
> +       if (ret < 0) {
> +               dout("failed to write src file (%zd)\n", ret);
> +               goto out;
> +       }
> +       ret = file_write_and_wait_range(dst_file, dst_off, (dst_off + len));
> +       if (ret < 0) {
> +               dout("failed to write dst file (%zd)\n", ret);
>                 goto out;
> +       }
>
>         /*
>          * We need FILE_WR caps for dst_ci and FILE_RD for src_ci as other

Applied, thanks

Yan, Zheng