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Date: Mon, 25 Sep 2023 09:54:37 -0400
From: Chuck Lever <chuck.lever@...cle.com>
To: Lorenzo Bianconi <lorenzo@...nel.org>
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 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.
> + attributes:
> + -
> + name: threads
> + type: u32
> + -
> + name: max-blksize
> + type: u32
> + -
> + name: max-conn
> + type: u32
>
> operations:
> list:
> @@ -72,3 +84,54 @@ operations:
> dump:
> pre: nfsd-nl-rpc-status-get-start
> post: nfsd-nl-rpc-status-get-done
> + -
> + name: threads-set
> + doc: set the number of running threads
> + attribute-set: server-attr
> + flags: [ admin-perm ]
> + do:
> + request:
> + attributes:
> + - threads
> + -
> + name: threads-get
> + doc: dump the number of running threads
> + attribute-set: server-attr
> + dump:
> + reply:
> + attributes:
> + - threads
> + -
> + name: max-blksize-set
> + doc: set the nfs block size
> + attribute-set: server-attr
> + flags: [ admin-perm ]
> + do:
> + request:
> + attributes:
> + - max-blksize
> + -
> + name: max-blksize-get
> + doc: dump the nfs block size
> + attribute-set: server-attr
> + dump:
> + reply:
> + attributes:
> + - max-blksize
> + -
> + name: max-conn-set
> + doc: set the max number of connections
> + attribute-set: server-attr
> + flags: [ admin-perm ]
> + do:
> + request:
> + attributes:
> + - max-conn
> + -
> + name: max-conn-get
> + doc: dump the max number of connections
> + attribute-set: server-attr
> + dump:
> + reply:
> + attributes:
> + - max-conn
> diff --git a/fs/nfsd/netlink.c b/fs/nfsd/netlink.c
> index 0e1d635ec5f9..f3dde1b1e162 100644
> --- a/fs/nfsd/netlink.c
> +++ b/fs/nfsd/netlink.c
> @@ -10,6 +10,21 @@
>
> #include <uapi/linux/nfsd_netlink.h>
>
> +/* NFSD_CMD_THREADS_SET - do */
> +static const struct nla_policy nfsd_threads_set_nl_policy[NFSD_A_SERVER_ATTR_THREADS + 1] = {
> + [NFSD_A_SERVER_ATTR_THREADS] = { .type = NLA_U32, },
> +};
> +
> +/* NFSD_CMD_MAX_BLKSIZE_SET - do */
> +static const struct nla_policy nfsd_max_blksize_set_nl_policy[NFSD_A_SERVER_ATTR_MAX_BLKSIZE + 1] = {
> + [NFSD_A_SERVER_ATTR_MAX_BLKSIZE] = { .type = NLA_U32, },
> +};
> +
> +/* NFSD_CMD_MAX_CONN_SET - do */
> +static const struct nla_policy nfsd_max_conn_set_nl_policy[NFSD_A_SERVER_ATTR_MAX_CONN + 1] = {
> + [NFSD_A_SERVER_ATTR_MAX_CONN] = { .type = NLA_U32, },
> +};
> +
> /* Ops table for nfsd */
> static const struct genl_split_ops nfsd_nl_ops[] = {
> {
> @@ -19,6 +34,42 @@ static const struct genl_split_ops nfsd_nl_ops[] = {
> .done = nfsd_nl_rpc_status_get_done,
> .flags = GENL_CMD_CAP_DUMP,
> },
> + {
> + .cmd = NFSD_CMD_THREADS_SET,
> + .doit = nfsd_nl_threads_set_doit,
> + .policy = nfsd_threads_set_nl_policy,
> + .maxattr = NFSD_A_SERVER_ATTR_THREADS,
> + .flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
> + },
> + {
> + .cmd = NFSD_CMD_THREADS_GET,
> + .dumpit = nfsd_nl_threads_get_dumpit,
> + .flags = GENL_CMD_CAP_DUMP,
> + },
> + {
> + .cmd = NFSD_CMD_MAX_BLKSIZE_SET,
> + .doit = nfsd_nl_max_blksize_set_doit,
> + .policy = nfsd_max_blksize_set_nl_policy,
> + .maxattr = NFSD_A_SERVER_ATTR_MAX_BLKSIZE,
> + .flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
> + },
> + {
> + .cmd = NFSD_CMD_MAX_BLKSIZE_GET,
> + .dumpit = nfsd_nl_max_blksize_get_dumpit,
> + .flags = GENL_CMD_CAP_DUMP,
> + },
> + {
> + .cmd = NFSD_CMD_MAX_CONN_SET,
> + .doit = nfsd_nl_max_conn_set_doit,
> + .policy = nfsd_max_conn_set_nl_policy,
> + .maxattr = NFSD_A_SERVER_ATTR_MAX_CONN,
> + .flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
> + },
> + {
> + .cmd = NFSD_CMD_MAX_CONN_GET,
> + .dumpit = nfsd_nl_max_conn_get_dumpit,
> + .flags = GENL_CMD_CAP_DUMP,
> + },
> };
>
> struct genl_family nfsd_nl_family __ro_after_init = {
> diff --git a/fs/nfsd/netlink.h b/fs/nfsd/netlink.h
> index d83dd6bdee92..41b95651c638 100644
> --- a/fs/nfsd/netlink.h
> +++ b/fs/nfsd/netlink.h
> @@ -16,6 +16,15 @@ int nfsd_nl_rpc_status_get_done(struct netlink_callback *cb);
>
> int nfsd_nl_rpc_status_get_dumpit(struct sk_buff *skb,
> struct netlink_callback *cb);
> +int nfsd_nl_threads_set_doit(struct sk_buff *skb, struct genl_info *info);
> +int nfsd_nl_threads_get_dumpit(struct sk_buff *skb,
> + struct netlink_callback *cb);
> +int nfsd_nl_max_blksize_set_doit(struct sk_buff *skb, struct genl_info *info);
> +int nfsd_nl_max_blksize_get_dumpit(struct sk_buff *skb,
> + struct netlink_callback *cb);
> +int nfsd_nl_max_conn_set_doit(struct sk_buff *skb, struct genl_info *info);
> +int nfsd_nl_max_conn_get_dumpit(struct sk_buff *skb,
> + struct netlink_callback *cb);
>
> extern struct genl_family nfsd_nl_family;
>
> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> index b71744e355a8..0167b7fd0d63 100644
> --- a/fs/nfsd/nfsctl.c
> +++ b/fs/nfsd/nfsctl.c
> @@ -1694,6 +1694,145 @@ int nfsd_nl_rpc_status_get_done(struct netlink_callback *cb)
> return 0;
> }
>
> +/**
> + * 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?
> + 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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