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Date: Mon, 25 Sep 2023 16:31:57 +0200
From: Lorenzo Bianconi <lorenzo@...nel.org>
To: Chuck Lever <chuck.lever@...cle.com>
Cc: linux-nfs@...r.kernel.org, lorenzo.bianconi@...hat.com,
jlayton@...nel.org, neilb@...e.de, netdev@...r.kernel.org
Subject: Re: [PATCH v2] NFSD: convert write_threads, write_maxblksize and
write_maxconn to netlink commands
On Sep 25, Chuck Lever wrote:
> On Sun, Sep 24, 2023 at 03:52:28PM +0200, Lorenzo Bianconi wrote:
> > Introduce write_threads, write_maxblksize and write_maxconn netlink
> > commands similar to the ones available through the procfs.
> >
> > Signed-off-by: Lorenzo Bianconi <lorenzo@...nel.org>
> > ---
> > Changes since v1:
> > - remove write_v4_end_grace command
> > - add write_maxblksize and write_maxconn netlink commands
> >
> > This patch can be tested with user-space tool reported below:
> > https://github.com/LorenzoBianconi/nfsd-netlink.git
> > ---
> > Documentation/netlink/specs/nfsd.yaml | 63 ++++++++++++
> > fs/nfsd/netlink.c | 51 ++++++++++
> > fs/nfsd/netlink.h | 9 ++
> > fs/nfsd/nfsctl.c | 139 ++++++++++++++++++++++++++
> > include/uapi/linux/nfsd_netlink.h | 15 +++
> > 5 files changed, 277 insertions(+)
>
> This looks pretty close to me. A couple of comments below.
>
>
> > diff --git a/Documentation/netlink/specs/nfsd.yaml b/Documentation/netlink/specs/nfsd.yaml
> > index 403d3e3a04f3..10214fcec8a5 100644
> > --- a/Documentation/netlink/specs/nfsd.yaml
> > +++ b/Documentation/netlink/specs/nfsd.yaml
> > @@ -62,6 +62,18 @@ attribute-sets:
> > name: compound-ops
> > type: u32
> > multi-attr: true
> > + -
> > + name: server-attr
>
> Or, say, "control-plane" ? "server-attr" doesn't seem very self-
> explanatory or specific.
ack, fine to me..naming is always hard :)
>
>
> > + attributes:
> > + -
> > + name: threads
> > + type: u32
> > + -
> > + name: max-blksize
> > + type: u32
> > + -
> > + name: max-conn
> > + type: u32
> >
> > operations:
> > list:
> > @@ -72,3 +84,54 @@ operations:
> > dump:
[...]
> >
> > +/**
> > + * nfsd_nl_threads_set_doit - set the number of running threads
> > + * @skb: reply buffer
> > + * @info: netlink metadata and command arguments
> > + *
> > + * Return 0 on success or a negative errno.
> > + */
> > +int nfsd_nl_threads_set_doit(struct sk_buff *skb, struct genl_info *info)
> > +{
> > + u16 nthreads;
> > + int ret;
> > +
> > + if (!info->attrs[NFSD_A_SERVER_ATTR_THREADS])
> > + return -EINVAL;
> > +
> > + nthreads = nla_get_u32(info->attrs[NFSD_A_SERVER_ATTR_THREADS]);
>
> I worry about what happens if someone sends down a value larger than
> 64K. While not a likely scenario, the behavior is not well defined,
> and I don't think the implicit type conversions are necessary.
>
> Can nthreads be u32?
actually this is a leftover of the previous patch. I will fix it in v3.
Regards,
Lorenzo
>
>
> > + ret = nfsd_svc(nthreads, genl_info_net(info), get_current_cred());
> > + return ret == nthreads ? 0 : ret;
> > +}
> > +
> > +static int nfsd_nl_get_dump(struct sk_buff *skb, struct netlink_callback *cb,
> > + int cmd, int attr, u32 val)
> > +{
> > + void *hdr;
> > +
> > + if (cb->args[0]) /* already consumed */
> > + return 0;
> > +
> > + hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
> > + &nfsd_nl_family, NLM_F_MULTI, cmd);
> > + if (!hdr)
> > + return -ENOBUFS;
> > +
> > + if (nla_put_u32(skb, attr, val))
> > + return -ENOBUFS;
> > +
> > + genlmsg_end(skb, hdr);
> > + cb->args[0] = 1;
> > +
> > + return skb->len;
> > +}
> > +
> > +/**
> > + * nfsd_nl_threads_get_dumpit - dump the number of running threads
> > + * @skb: reply buffer
> > + * @cb: netlink metadata and command arguments
> > + *
> > + * Returns the size of the reply or a negative errno.
> > + */
> > +int nfsd_nl_threads_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
> > +{
> > + return nfsd_nl_get_dump(skb, cb, NFSD_CMD_THREADS_GET,
> > + NFSD_A_SERVER_ATTR_THREADS,
> > + nfsd_nrthreads(sock_net(skb->sk)));
> > +}
> > +
> > +/**
> > + * nfsd_nl_max_blksize_set_doit - set the nfs block size
> > + * @skb: reply buffer
> > + * @info: netlink metadata and command arguments
> > + *
> > + * Return 0 on success or a negative errno.
> > + */
> > +int nfsd_nl_max_blksize_set_doit(struct sk_buff *skb, struct genl_info *info)
> > +{
> > + struct nfsd_net *nn = net_generic(genl_info_net(info), nfsd_net_id);
> > + int ret = 0;
> > +
> > + if (!info->attrs[NFSD_A_SERVER_ATTR_MAX_BLKSIZE])
> > + return -EINVAL;
> > +
> > + mutex_lock(&nfsd_mutex);
> > + if (nn->nfsd_serv) {
> > + ret = -EBUSY;
> > + goto out;
> > + }
> > +
> > + nfsd_max_blksize = nla_get_u32(info->attrs[NFSD_A_SERVER_ATTR_MAX_BLKSIZE]);
> > + nfsd_max_blksize = max_t(int, nfsd_max_blksize, 1024);
> > + nfsd_max_blksize = min_t(int, nfsd_max_blksize, NFSSVC_MAXBLKSIZE);
> > + nfsd_max_blksize &= ~1023;
> > +out:
> > + mutex_unlock(&nfsd_mutex);
> > +
> > + return ret;
> > +}
> > +
> > +/**
> > + * nfsd_nl_max_blksize_get_dumpit - dump the nfs block size
> > + * @skb: reply buffer
> > + * @cb: netlink metadata and command arguments
> > + *
> > + * Returns the size of the reply or a negative errno.
> > + */
> > +int nfsd_nl_max_blksize_get_dumpit(struct sk_buff *skb,
> > + struct netlink_callback *cb)
> > +{
> > + return nfsd_nl_get_dump(skb, cb, NFSD_CMD_MAX_BLKSIZE_GET,
> > + NFSD_A_SERVER_ATTR_MAX_BLKSIZE,
> > + nfsd_max_blksize);
> > +}
> > +
> > +/**
> > + * nfsd_nl_max_conn_set_doit - set the max number of connections
> > + * @skb: reply buffer
> > + * @info: netlink metadata and command arguments
> > + *
> > + * Return 0 on success or a negative errno.
> > + */
> > +int nfsd_nl_max_conn_set_doit(struct sk_buff *skb, struct genl_info *info)
> > +{
> > + struct nfsd_net *nn = net_generic(genl_info_net(info), nfsd_net_id);
> > +
> > + if (!info->attrs[NFSD_A_SERVER_ATTR_MAX_CONN])
> > + return -EINVAL;
> > +
> > + nn->max_connections = nla_get_u32(info->attrs[NFSD_A_SERVER_ATTR_MAX_CONN]);
> > +
> > + return 0;
> > +}
> > +
> > +/**
> > + * nfsd_nl_max_conn_get_dumpit - dump the max number of connections
> > + * @skb: reply buffer
> > + * @cb: netlink metadata and command arguments
> > + *
> > + * Returns the size of the reply or a negative errno.
> > + */
> > +int nfsd_nl_max_conn_get_dumpit(struct sk_buff *skb,
> > + struct netlink_callback *cb)
> > +{
> > + struct nfsd_net *nn = net_generic(sock_net(cb->skb->sk), nfsd_net_id);
> > +
> > + return nfsd_nl_get_dump(skb, cb, NFSD_CMD_MAX_CONN_GET,
> > + NFSD_A_SERVER_ATTR_MAX_CONN,
> > + nn->max_connections);
> > +}
> > +
> > /**
> > * nfsd_net_init - Prepare the nfsd_net portion of a new net namespace
> > * @net: a freshly-created network namespace
> > diff --git a/include/uapi/linux/nfsd_netlink.h b/include/uapi/linux/nfsd_netlink.h
> > index c8ae72466ee6..59d0aa22ba94 100644
> > --- a/include/uapi/linux/nfsd_netlink.h
> > +++ b/include/uapi/linux/nfsd_netlink.h
> > @@ -29,8 +29,23 @@ enum {
> > NFSD_A_RPC_STATUS_MAX = (__NFSD_A_RPC_STATUS_MAX - 1)
> > };
> >
> > +enum {
> > + NFSD_A_SERVER_ATTR_THREADS = 1,
> > + NFSD_A_SERVER_ATTR_MAX_BLKSIZE,
> > + NFSD_A_SERVER_ATTR_MAX_CONN,
> > +
> > + __NFSD_A_SERVER_ATTR_MAX,
> > + NFSD_A_SERVER_ATTR_MAX = (__NFSD_A_SERVER_ATTR_MAX - 1)
> > +};
> > +
> > enum {
> > NFSD_CMD_RPC_STATUS_GET = 1,
> > + NFSD_CMD_THREADS_SET,
> > + NFSD_CMD_THREADS_GET,
> > + NFSD_CMD_MAX_BLKSIZE_SET,
> > + NFSD_CMD_MAX_BLKSIZE_GET,
> > + NFSD_CMD_MAX_CONN_SET,
> > + NFSD_CMD_MAX_CONN_GET,
> >
> > __NFSD_CMD_MAX,
> > NFSD_CMD_MAX = (__NFSD_CMD_MAX - 1)
> > --
> > 2.41.0
> >
>
> --
> Chuck Lever
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