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From:   Ilya Dryomov <idryomov@gmail.com>
Date:   Mon, 27 Jan 2020 18:47:02 +0100
Message-ID: <CAOi1vP9S3w13axR3FYxqFSZ1uF2V=0aMfnkcsMptMKL4W+-wEA@mail.gmail.com>
Subject: Re: [RFC PATCH 1/3] libceph: add non-blocking version of ceph_osdc_copy_from()
To:     Luis Henriques <lhenriques@suse.com>
Cc:     Jeff Layton <jlayton@kernel.org>, Sage Weil <sage@redhat.com>,
        "Yan, Zheng" <zyan@redhat.com>,
        Gregory Farnum <gfarnum@redhat.com>,
        Ceph Development <ceph-devel@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
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Sender: linux-kernel-owner@vger.kernel.org
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On Mon, Jan 27, 2020 at 5:43 PM Luis Henriques <lhenriques@suse.com> wrote:
>
> A non-blocking version of ceph_osdc_copy_from will allow for callers to
> send 'copy-from' requests in bulk and wait for all of them to complete in
> the end.
>
> Signed-off-by: Luis Henriques <lhenriques@suse.com>
> ---
>  include/linux/ceph/osd_client.h | 12 ++++++++
>  net/ceph/osd_client.c           | 54 +++++++++++++++++++++++++--------
>  2 files changed, 53 insertions(+), 13 deletions(-)
>
> diff --git a/include/linux/ceph/osd_client.h b/include/linux/ceph/osd_client.h
> index 5a62dbd3f4c2..7916a178d137 100644
> --- a/include/linux/ceph/osd_client.h
> +++ b/include/linux/ceph/osd_client.h
> @@ -537,6 +537,18 @@ int ceph_osdc_copy_from(struct ceph_osd_client *osdc,
>                         u32 truncate_seq, u64 truncate_size,
>                         u8 copy_from_flags);
>
> +struct ceph_osd_request *ceph_osdc_copy_from_nowait(
> +                       struct ceph_osd_client *osdc,
> +                       u64 src_snapid, u64 src_version,
> +                       struct ceph_object_id *src_oid,
> +                       struct ceph_object_locator *src_oloc,
> +                       u32 src_fadvise_flags,
> +                       struct ceph_object_id *dst_oid,
> +                       struct ceph_object_locator *dst_oloc,
> +                       u32 dst_fadvise_flags,
> +                       u32 truncate_seq, u64 truncate_size,
> +                       u8 copy_from_flags);
> +
>  /* watch/notify */
>  struct ceph_osd_linger_request *
>  ceph_osdc_watch(struct ceph_osd_client *osdc,
> diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
> index b68b376d8c2f..7f984532f37c 100644
> --- a/net/ceph/osd_client.c
> +++ b/net/ceph/osd_client.c
> @@ -5346,23 +5346,24 @@ static int osd_req_op_copy_from_init(struct ceph_osd_request *req,
>         return 0;
>  }
>
> -int ceph_osdc_copy_from(struct ceph_osd_client *osdc,
> -                       u64 src_snapid, u64 src_version,
> -                       struct ceph_object_id *src_oid,
> -                       struct ceph_object_locator *src_oloc,
> -                       u32 src_fadvise_flags,
> -                       struct ceph_object_id *dst_oid,
> -                       struct ceph_object_locator *dst_oloc,
> -                       u32 dst_fadvise_flags,
> -                       u32 truncate_seq, u64 truncate_size,
> -                       u8 copy_from_flags)
> +struct ceph_osd_request *ceph_osdc_copy_from_nowait(
> +               struct ceph_osd_client *osdc,
> +               u64 src_snapid, u64 src_version,
> +               struct ceph_object_id *src_oid,
> +               struct ceph_object_locator *src_oloc,
> +               u32 src_fadvise_flags,
> +               struct ceph_object_id *dst_oid,
> +               struct ceph_object_locator *dst_oloc,
> +               u32 dst_fadvise_flags,
> +               u32 truncate_seq, u64 truncate_size,
> +               u8 copy_from_flags)
>  {
>         struct ceph_osd_request *req;
>         int ret;
>
>         req = ceph_osdc_alloc_request(osdc, NULL, 1, false, GFP_KERNEL);
>         if (!req)
> -               return -ENOMEM;
> +               return ERR_PTR(-ENOMEM);
>
>         req->r_flags = CEPH_OSD_FLAG_WRITE;
>
> @@ -5381,11 +5382,38 @@ int ceph_osdc_copy_from(struct ceph_osd_client *osdc,
>                 goto out;
>
>         ceph_osdc_start_request(osdc, req, false);
> -       ret = ceph_osdc_wait_request(osdc, req);
> +       return req;
>
>  out:
>         ceph_osdc_put_request(req);
> -       return ret;
> +       return ERR_PTR(ret);
> +}
> +EXPORT_SYMBOL(ceph_osdc_copy_from_nowait);
> +
> +int ceph_osdc_copy_from(struct ceph_osd_client *osdc,
> +                       u64 src_snapid, u64 src_version,
> +                       struct ceph_object_id *src_oid,
> +                       struct ceph_object_locator *src_oloc,
> +                       u32 src_fadvise_flags,
> +                       struct ceph_object_id *dst_oid,
> +                       struct ceph_object_locator *dst_oloc,
> +                       u32 dst_fadvise_flags,
> +                       u32 truncate_seq, u64 truncate_size,
> +                       u8 copy_from_flags)
> +{
> +       struct ceph_osd_request *req;
> +
> +       req = ceph_osdc_copy_from_nowait(osdc,
> +                       src_snapid, src_version,
> +                       src_oid, src_oloc,
> +                       src_fadvise_flags,
> +                       dst_oid, dst_oloc,
> +                       dst_fadvise_flags,
> +                       truncate_seq, truncate_size,
> +                       copy_from_flags);
> +       if (IS_ERR(req))
> +               return PTR_ERR(req);
> +       return ceph_osdc_wait_request(osdc, req);

I don't think we need a blocking version.  Change ceph_osdc_copy_from()
and keep the name -- no need for async or nowait suffixes.

Thanks,

                Ilya