From: Jeff Layton Date: Wed, 25 Mar 2026 14:40:34 +0000 (-0400) Subject: nfsd: add NFSD_CMD_CACHE_FLUSH netlink command X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=70b7e3526c53d9dd7caccdbeff5b0485640d8cf1;p=thirdparty%2Fkernel%2Flinux.git nfsd: add NFSD_CMD_CACHE_FLUSH netlink command Add a new NFSD_CMD_CACHE_FLUSH generic netlink command that allows userspace to flush the nfsd export caches (svc_export and expkey) without writing to /proc/net/rpc/*/flush. An optional NFSD_A_CACHE_FLUSH_MASK u32 attribute selects which caches to flush (bit 1 = svc_export, bit 2 = expkey). If the attribute is omitted, all nfsd caches are flushed. This is used by exportfs to replace its /proc-based cache_flush() with a netlink equivalent, with /proc fallback for older kernels. Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever --- diff --git a/Documentation/netlink/specs/nfsd.yaml b/Documentation/netlink/specs/nfsd.yaml index 7030b40273fd4..40eca7c156803 100644 --- a/Documentation/netlink/specs/nfsd.yaml +++ b/Documentation/netlink/specs/nfsd.yaml @@ -293,6 +293,14 @@ attribute-sets: type: nest nested-attributes: expkey multi-attr: true + - + name: cache-flush + attributes: + - + name: mask + type: u32 + enum: cache-type + enum-as-flags: true operations: list: @@ -438,6 +446,15 @@ operations: request: attributes: - requests + - + name: cache-flush + doc: Flush nfsd caches (svc_export and/or expkey) + attribute-set: cache-flush + flags: [admin-perm] + do: + request: + attributes: + - mask mcast-groups: list: diff --git a/fs/nfsd/netlink.c b/fs/nfsd/netlink.c index 394230e250a5b..30c4f8be3df98 100644 --- a/fs/nfsd/netlink.c +++ b/fs/nfsd/netlink.c @@ -108,6 +108,11 @@ static const struct nla_policy nfsd_expkey_set_reqs_nl_policy[NFSD_A_EXPKEY_REQS [NFSD_A_EXPKEY_REQS_REQUESTS] = NLA_POLICY_NESTED(nfsd_expkey_nl_policy), }; +/* NFSD_CMD_CACHE_FLUSH - do */ +static const struct nla_policy nfsd_cache_flush_nl_policy[NFSD_A_CACHE_FLUSH_MASK + 1] = { + [NFSD_A_CACHE_FLUSH_MASK] = NLA_POLICY_MASK(NLA_U32, 0x3), +}; + /* Ops table for nfsd */ static const struct genl_split_ops nfsd_nl_ops[] = { { @@ -191,6 +196,13 @@ static const struct genl_split_ops nfsd_nl_ops[] = { .maxattr = NFSD_A_EXPKEY_REQS_REQUESTS, .flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO, }, + { + .cmd = NFSD_CMD_CACHE_FLUSH, + .doit = nfsd_nl_cache_flush_doit, + .policy = nfsd_cache_flush_nl_policy, + .maxattr = NFSD_A_CACHE_FLUSH_MASK, + .flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO, + }, }; static const struct genl_multicast_group nfsd_nl_mcgrps[] = { diff --git a/fs/nfsd/netlink.h b/fs/nfsd/netlink.h index f5b3387772850..cc89732ed71bd 100644 --- a/fs/nfsd/netlink.h +++ b/fs/nfsd/netlink.h @@ -38,6 +38,7 @@ int nfsd_nl_svc_export_set_reqs_doit(struct sk_buff *skb, int nfsd_nl_expkey_get_reqs_dumpit(struct sk_buff *skb, struct netlink_callback *cb); int nfsd_nl_expkey_set_reqs_doit(struct sk_buff *skb, struct genl_info *info); +int nfsd_nl_cache_flush_doit(struct sk_buff *skb, struct genl_info *info); enum { NFSD_NLGRP_NONE, diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c index c93cf82e36475..bfb937e8ad7ca 100644 --- a/fs/nfsd/nfsctl.c +++ b/fs/nfsd/nfsctl.c @@ -10,6 +10,7 @@ #include #include +#include #include #include #include @@ -2212,6 +2213,41 @@ err_free_msg: return err; } +/** + * nfsd_nl_cache_flush_doit - flush nfsd caches via netlink + * @skb: reply buffer + * @info: netlink metadata and command arguments + * + * Flush the svc_export and/or expkey caches. If NFSD_A_CACHE_FLUSH_MASK + * is provided, only flush the caches indicated by the bitmask (bit 0 = + * svc_export, bit 1 = expkey). If omitted, flush both. + * + * Return 0 on success or a negative errno. + */ +int nfsd_nl_cache_flush_doit(struct sk_buff *skb, struct genl_info *info) +{ + struct net *net = genl_info_net(info); + struct nfsd_net *nn = net_generic(net, nfsd_net_id); + u32 mask = ~0U; + + if (info->attrs[NFSD_A_CACHE_FLUSH_MASK]) + mask = nla_get_u32(info->attrs[NFSD_A_CACHE_FLUSH_MASK]); + + mutex_lock(&nfsd_mutex); + + if ((mask & NFSD_CACHE_TYPE_SVC_EXPORT) && + nn->svc_export_cache) + cache_purge(nn->svc_export_cache); + + if ((mask & NFSD_CACHE_TYPE_EXPKEY) && + nn->svc_expkey_cache) + cache_purge(nn->svc_expkey_cache); + + mutex_unlock(&nfsd_mutex); + + return 0; +} + int nfsd_cache_notify(struct cache_detail *cd, struct cache_head *h, u32 cache_type) { struct genlmsghdr *hdr; diff --git a/include/uapi/linux/nfsd_netlink.h b/include/uapi/linux/nfsd_netlink.h index fed7533c15333..060c43675599f 100644 --- a/include/uapi/linux/nfsd_netlink.h +++ b/include/uapi/linux/nfsd_netlink.h @@ -197,6 +197,13 @@ enum { NFSD_A_EXPKEY_REQS_MAX = (__NFSD_A_EXPKEY_REQS_MAX - 1) }; +enum { + NFSD_A_CACHE_FLUSH_MASK = 1, + + __NFSD_A_CACHE_FLUSH_MAX, + NFSD_A_CACHE_FLUSH_MAX = (__NFSD_A_CACHE_FLUSH_MAX - 1) +}; + enum { NFSD_CMD_RPC_STATUS_GET = 1, NFSD_CMD_THREADS_SET, @@ -212,6 +219,7 @@ enum { NFSD_CMD_SVC_EXPORT_SET_REQS, NFSD_CMD_EXPKEY_GET_REQS, NFSD_CMD_EXPKEY_SET_REQS, + NFSD_CMD_CACHE_FLUSH, __NFSD_CMD_MAX, NFSD_CMD_MAX = (__NFSD_CMD_MAX - 1)