[PATCH 0/9 RFC v2] NFS sysfs scaffolding

[PATCH 0/9 RFC v2] NFS sysfs scaffolding

[Benjamin Coddington]

Here's another round of sysfs entries for each nfs_server, this time with a
single use-case: a "shutdown" toggle that causes the basic rpc_clnt(s) to
immediately fail tasks with -EIO.  It works well for the non pNFS cases to
allow an unmount of a filesystem when the NFS server has gone away.

I'm posting to gain potential NACKing, or to be redirected, or to serve as
fodder for discussion at LSF.

I'm thinking I'd like to toggle v4.2 things like READ_PLUS in here next, or
other module-level options that maybe would be useful per-mount.

Benjamin Coddington (9):
  NFS: rename nfs_client_kset to nfs_kset
  NFS: rename nfs_client_kobj to nfs_net_kobj
  NFS: add superblock sysfs entries
  NFS: Add sysfs links to sunrpc clients for nfs_clients
  NFS: add a sysfs link to the lockd rpc_client
  NFS: add a sysfs link to the acl rpc_client
  NFS: add sysfs shutdown knob
  NFS: Cleanup unused rpc_clnt variable
  NFSv4: Clean up some shutdown loops

 fs/lockd/clntlock.c         |   6 ++
 fs/nfs/client.c             |  21 +++++
 fs/nfs/nfs3client.c         |   4 +
 fs/nfs/nfs4client.c         |   2 +
 fs/nfs/nfs4proc.c           |   2 +-
 fs/nfs/nfs4state.c          |   5 +-
 fs/nfs/super.c              |   6 +-
 fs/nfs/sysfs.c              | 148 +++++++++++++++++++++++++++++++++---
 fs/nfs/sysfs.h              |   9 ++-
 include/linux/lockd/bind.h  |   2 +
 include/linux/nfs_fs_sb.h   |   3 +
 include/linux/sunrpc/clnt.h |  11 ++-
 net/sunrpc/clnt.c           |   5 ++
 net/sunrpc/sysfs.h          |   7 --
 14 files changed, 204 insertions(+), 27 deletions(-)

-- 
2.39.2

[PATCH 1/9] NFS: rename nfs_client_kset to nfs_kset

[Benjamin Coddington]

Be brief and match the subsystem name.  There's no need to distinguish this
kset variable from the server.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
---
 fs/nfs/sysfs.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/fs/nfs/sysfs.c b/fs/nfs/sysfs.c
index 0cbcd2dfa732..81d98727b79f 100644
--- a/fs/nfs/sysfs.c
+++ b/fs/nfs/sysfs.c
@@ -18,7 +18,7 @@
 #include "sysfs.h"
 
 struct kobject *nfs_client_kobj;
-static struct kset *nfs_client_kset;
+static struct kset *nfs_kset;
 
 static void nfs_netns_object_release(struct kobject *kobj)
 {
@@ -55,13 +55,13 @@ static struct kobject *nfs_netns_object_alloc(const char *name,
 
 int nfs_sysfs_init(void)
 {
-	nfs_client_kset = kset_create_and_add("nfs", NULL, fs_kobj);
-	if (!nfs_client_kset)
+	nfs_kset = kset_create_and_add("nfs", NULL, fs_kobj);
+	if (!nfs_kset)
 		return -ENOMEM;
-	nfs_client_kobj = nfs_netns_object_alloc("net", nfs_client_kset, NULL);
+	nfs_client_kobj = nfs_netns_object_alloc("net", nfs_kset, NULL);
 	if  (!nfs_client_kobj) {
-		kset_unregister(nfs_client_kset);
-		nfs_client_kset = NULL;
+		kset_unregister(nfs_kset);
+		nfs_kset = NULL;
 		return -ENOMEM;
 	}
 	return 0;
@@ -70,7 +70,7 @@ int nfs_sysfs_init(void)
 void nfs_sysfs_exit(void)
 {
 	kobject_put(nfs_client_kobj);
-	kset_unregister(nfs_client_kset);
+	kset_unregister(nfs_kset);
 }
 
 static ssize_t nfs_netns_identifier_show(struct kobject *kobj,
@@ -159,7 +159,7 @@ static struct nfs_netns_client *nfs_netns_client_alloc(struct kobject *parent,
 	p = kzalloc(sizeof(*p), GFP_KERNEL);
 	if (p) {
 		p->net = net;
-		p->kobject.kset = nfs_client_kset;
+		p->kobject.kset = nfs_kset;
 		if (kobject_init_and_add(&p->kobject, &nfs_netns_client_type,
 					parent, "nfs_client") == 0)
 			return p;
-- 
2.39.2

[PATCH 2/9] NFS: rename nfs_client_kobj to nfs_net_kobj

[Benjamin Coddington]

Match the variable names to the sysfs structure.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
---
 fs/nfs/sysfs.c | 10 +++++-----
 fs/nfs/sysfs.h |  2 +-
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/nfs/sysfs.c b/fs/nfs/sysfs.c
index 81d98727b79f..a496e26fcfb7 100644
--- a/fs/nfs/sysfs.c
+++ b/fs/nfs/sysfs.c
@@ -17,7 +17,7 @@
 #include "netns.h"
 #include "sysfs.h"
 
-struct kobject *nfs_client_kobj;
+struct kobject *nfs_net_kobj;
 static struct kset *nfs_kset;
 
 static void nfs_netns_object_release(struct kobject *kobj)
@@ -58,8 +58,8 @@ int nfs_sysfs_init(void)
 	nfs_kset = kset_create_and_add("nfs", NULL, fs_kobj);
 	if (!nfs_kset)
 		return -ENOMEM;
-	nfs_client_kobj = nfs_netns_object_alloc("net", nfs_kset, NULL);
-	if  (!nfs_client_kobj) {
+	nfs_net_kobj = nfs_netns_object_alloc("net", nfs_kset, NULL);
+	if  (!nfs_net_kobj) {
 		kset_unregister(nfs_kset);
 		nfs_kset = NULL;
 		return -ENOMEM;
@@ -69,7 +69,7 @@ int nfs_sysfs_init(void)
 
 void nfs_sysfs_exit(void)
 {
-	kobject_put(nfs_client_kobj);
+	kobject_put(nfs_net_kobj);
 	kset_unregister(nfs_kset);
 }
 
@@ -172,7 +172,7 @@ void nfs_netns_sysfs_setup(struct nfs_net *netns, struct net *net)
 {
 	struct nfs_netns_client *clp;
 
-	clp = nfs_netns_client_alloc(nfs_client_kobj, net);
+	clp = nfs_netns_client_alloc(nfs_net_kobj, net);
 	if (clp) {
 		netns->nfs_client = clp;
 		kobject_uevent(&clp->kobject, KOBJ_ADD);
diff --git a/fs/nfs/sysfs.h b/fs/nfs/sysfs.h
index 5501ef573c32..0423aaf388c9 100644
--- a/fs/nfs/sysfs.h
+++ b/fs/nfs/sysfs.h
@@ -14,7 +14,7 @@ struct nfs_netns_client {
 	const char __rcu *identifier;
 };
 
-extern struct kobject *nfs_client_kobj;
+extern struct kobject *nfs_net_kobj;
 
 extern int nfs_sysfs_init(void);
 extern void nfs_sysfs_exit(void);
-- 
2.39.2

[PATCH 3/9] NFS: add superblock sysfs entries

[Benjamin Coddington]

Create a sysfs directory for each mount that corresponds to the mount's
nfs_server struct.  As the mount is being constructed, use the name
"server-n", but rename it to the "MAJOR:MINOR" of the mount after assigning
a device_id. The rename approach allows us to populate the mount's directory
with links to the various rpc_client objects during the mount's
construction.  The naming convention (MAJOR:MINOR) can be used to reference
a particular NFS mount's sysfs tree.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
---
 fs/nfs/client.c           | 15 ++++++++++
 fs/nfs/super.c            |  6 +++-
 fs/nfs/sysfs.c            | 58 +++++++++++++++++++++++++++++++++++++++
 fs/nfs/sysfs.h            |  5 ++++
 include/linux/nfs_fs_sb.h |  2 ++
 5 files changed, 85 insertions(+), 1 deletion(-)

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index f50e025ae406..72da715fc617 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -944,6 +944,8 @@ void nfs_server_remove_lists(struct nfs_server *server)
 }
 EXPORT_SYMBOL_GPL(nfs_server_remove_lists);
 
+static DEFINE_IDA(s_sysfs_ids);
+
 /*
  * Allocate and initialise a server record
  */
@@ -955,6 +957,13 @@ struct nfs_server *nfs_alloc_server(void)
 	if (!server)
 		return NULL;
 
+	server->s_sysfs_id = ida_simple_get(
+		&s_sysfs_ids, 0, 0, GFP_KERNEL);
+	if (server->s_sysfs_id < 0) {
+		kfree(server);
+		return NULL;
+	}
+
 	server->client = server->client_acl = ERR_PTR(-EINVAL);
 
 	/* Zero out the NFS state stuff */
@@ -979,6 +988,7 @@ struct nfs_server *nfs_alloc_server(void)
 	ida_init(&server->lockowner_id);
 	pnfs_init_server(server);
 	rpc_init_wait_queue(&server->uoc_rpcwaitq, "NFS UOC");
+	nfs_sysfs_add_server(server);
 
 	return server;
 }
@@ -1001,6 +1011,10 @@ void nfs_free_server(struct nfs_server *server)
 
 	nfs_put_client(server->nfs_client);
 
+	nfs_sysfs_remove_server(server);
+	kobject_put(&server->kobj);
+	ida_simple_remove(&s_sysfs_ids, server->s_sysfs_id);
+
 	ida_destroy(&server->lockowner_id);
 	ida_destroy(&server->openowner_id);
 	nfs_free_iostats(server->io_stats);
@@ -1385,6 +1399,7 @@ int __init nfs_fs_proc_init(void)
 void nfs_fs_proc_exit(void)
 {
 	remove_proc_subtree("fs/nfsfs", NULL);
+	ida_destroy(&s_sysfs_ids);
 }
 
 #endif /* CONFIG_PROC_FS */
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 05ae23657527..40a866db7965 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -68,6 +68,8 @@
 #include "nfs4session.h"
 #include "pnfs.h"
 #include "nfs.h"
+#include "netns.h"
+#include "sysfs.h"
 
 #define NFSDBG_FACILITY		NFSDBG_VFS
 
@@ -1088,6 +1090,7 @@ static void nfs_fill_super(struct super_block *sb, struct nfs_fs_context *ctx)
 						 &sb->s_blocksize_bits);
 
 	nfs_super_set_maxbytes(sb, server->maxfilesize);
+	nfs_sysfs_move_server_to_sb(sb);
 	server->has_sec_mnt_opts = ctx->has_sec_mnt_opts;
 }
 
@@ -1333,13 +1336,14 @@ int nfs_get_tree_common(struct fs_context *fc)
 }
 
 /*
- * Destroy an NFS2/3 superblock
+ * Destroy an NFS superblock
  */
 void nfs_kill_super(struct super_block *s)
 {
 	struct nfs_server *server = NFS_SB(s);
 	dev_t dev = s->s_dev;
 
+	nfs_sysfs_move_sb_to_server(server);
 	generic_shutdown_super(s);
 
 	nfs_fscache_release_super_cookie(s);
diff --git a/fs/nfs/sysfs.c b/fs/nfs/sysfs.c
index a496e26fcfb7..534e2293a698 100644
--- a/fs/nfs/sysfs.c
+++ b/fs/nfs/sysfs.c
@@ -190,3 +190,61 @@ void nfs_netns_sysfs_destroy(struct nfs_net *netns)
 		netns->nfs_client = NULL;
 	}
 }
+
+static void nfs_sysfs_sb_release(struct kobject *kobj)
+{
+	/* no-op: why? see lib/kobject.c kobject_cleanup() */
+}
+
+static struct attribute *nfs_mp_attrs[] = {
+        NULL,
+};
+
+ATTRIBUTE_GROUPS(nfs_mp);
+
+static struct kobj_type nfs_sb_ktype = {
+	.release = nfs_sysfs_sb_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = nfs_mp_groups,
+};
+
+void nfs_sysfs_add_server(struct nfs_server *server)
+{
+	int ret;
+
+	ret = kobject_init_and_add(&server->kobj, &nfs_sb_ktype,
+				&nfs_kset->kobj, "server-%d", server->s_sysfs_id);
+	if (ret < 0)
+		pr_warn("NFS: nfs sysfs add server-%d failed (%d)\n",
+					server->s_sysfs_id, ret);
+}
+
+void nfs_sysfs_move_server_to_sb(struct super_block *s)
+{
+	struct nfs_server *server = s->s_fs_info;
+	int ret;
+
+	ret = kobject_rename(&server->kobj, s->s_id);
+	if (ret < 0)
+		pr_warn("NFS: rename sysfs %s failed (%d)\n",
+					server->kobj.name, ret);
+}
+
+void nfs_sysfs_move_sb_to_server(struct nfs_server *server)
+{
+	const char *s;
+	int ret = -ENOMEM;
+
+	s = kasprintf(GFP_KERNEL, "server-%d", server->s_sysfs_id);
+	if (s)
+		ret = kobject_rename(&server->kobj, s);
+	if (ret < 0)
+		pr_warn("NFS: rename sysfs %s failed (%d)\n",
+					server->kobj.name, ret);
+}
+
+/* unlink, not dec-ref */
+void nfs_sysfs_remove_server(struct nfs_server *server)
+{
+	kobject_del(&server->kobj);
+}
diff --git a/fs/nfs/sysfs.h b/fs/nfs/sysfs.h
index 0423aaf388c9..0fc80fb55b3e 100644
--- a/fs/nfs/sysfs.h
+++ b/fs/nfs/sysfs.h
@@ -22,4 +22,9 @@ extern void nfs_sysfs_exit(void);
 void nfs_netns_sysfs_setup(struct nfs_net *netns, struct net *net);
 void nfs_netns_sysfs_destroy(struct nfs_net *netns);
 
+void nfs_sysfs_add_server(struct nfs_server *s);
+void nfs_sysfs_move_server_to_sb(struct super_block *s);
+void nfs_sysfs_move_sb_to_server(struct nfs_server *s);
+void nfs_sysfs_remove_server(struct nfs_server *s);
+
 #endif
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index ea2f7e6b1b0b..dee1664abca8 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -183,6 +183,7 @@ struct nfs_server {
 				change_attr_type;/* Description of change attribute */
 
 	struct nfs_fsid		fsid;
+	int			s_sysfs_id;	/* sysfs dentry index */
 	__u64			maxfilesize;	/* maximum file size */
 	struct timespec64	time_delta;	/* smallest time granularity */
 	unsigned long		mount_time;	/* when this fs was mounted */
@@ -259,6 +260,7 @@ struct nfs_server {
 	/* User namespace info */
 	const struct cred	*cred;
 	bool			has_sec_mnt_opts;
+	struct kobject	kobj;
 };
 
 /* Server capabilities */
-- 
2.39.2

[PATCH 4/9] NFS: Add sysfs links to sunrpc clients for nfs_clients

[Benjamin Coddington]

For the general and state management nfs_client under each mount, create
symlinks to their respective rpc_client sysfs entries.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
---
 fs/nfs/client.c             |  5 +++++
 fs/nfs/nfs4client.c         |  2 ++
 fs/nfs/sysfs.c              | 20 ++++++++++++++++++++
 fs/nfs/sysfs.h              |  2 ++
 include/linux/sunrpc/clnt.h |  8 +++++++-
 net/sunrpc/sysfs.h          |  7 -------
 6 files changed, 36 insertions(+), 8 deletions(-)

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 72da715fc617..de275f1fde92 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -621,6 +621,7 @@ int nfs_init_server_rpcclient(struct nfs_server *server,
 	if (server->flags & NFS_MOUNT_SOFT)
 		server->client->cl_softrtry = 1;
 
+	nfs_sysfs_link_rpc_client(server, server->client, NULL);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(nfs_init_server_rpcclient);
@@ -690,6 +691,7 @@ static int nfs_init_server(struct nfs_server *server,
 		return PTR_ERR(clp);
 
 	server->nfs_client = clp;
+	nfs_sysfs_link_rpc_client(server, clp->cl_rpcclient, "_state");
 
 	/* Initialise the client representation from the mount data */
 	server->flags = ctx->flags;
@@ -1116,6 +1118,9 @@ struct nfs_server *nfs_clone_server(struct nfs_server *source,
 
 	server->fsid = fattr->fsid;
 
+	nfs_sysfs_link_rpc_client(server,
+		server->nfs_client->cl_rpcclient, "_state");
+
 	error = nfs_init_server_rpcclient(server,
 			source->client->cl_timeout,
 			flavor);
diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index d3051b051a56..c7012f22a009 100644
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -18,6 +18,7 @@
 #include "nfs4idmap.h"
 #include "pnfs.h"
 #include "netns.h"
+#include "sysfs.h"
 
 #define NFSDBG_FACILITY		NFSDBG_CLIENT
 
@@ -947,6 +948,7 @@ static int nfs4_set_client(struct nfs_server *server,
 	set_bit(NFS_CS_CHECK_LEASE_TIME, &clp->cl_res_state);
 
 	server->nfs_client = clp;
+	nfs_sysfs_link_rpc_client(server, clp->cl_rpcclient, "_state");
 	return 0;
 }
 
diff --git a/fs/nfs/sysfs.c b/fs/nfs/sysfs.c
index 534e2293a698..e1b5df7a3df5 100644
--- a/fs/nfs/sysfs.c
+++ b/fs/nfs/sysfs.c
@@ -191,6 +191,26 @@ void nfs_netns_sysfs_destroy(struct nfs_net *netns)
 	}
 }
 
+#define RPC_CLIENT_NAME_SIZE 64
+
+void nfs_sysfs_link_rpc_client(struct nfs_server *server,
+			struct rpc_clnt *clnt, const char *uniq)
+{
+	char name[RPC_CLIENT_NAME_SIZE];
+	int ret;
+
+	strcpy(name, clnt->cl_program->name);
+	strcat(name, uniq ? uniq : "");
+	strcat(name, "_client");
+
+	ret = sysfs_create_link_nowarn(&server->kobj,
+						&clnt->cl_sysfs->kobject, name);
+	if (ret < 0)
+		pr_warn("NFS: can't create link to %s in sysfs (%d)\n",
+			name, ret);
+}
+EXPORT_SYMBOL_GPL(nfs_sysfs_link_rpc_client);
+
 static void nfs_sysfs_sb_release(struct kobject *kobj)
 {
 	/* no-op: why? see lib/kobject.c kobject_cleanup() */
diff --git a/fs/nfs/sysfs.h b/fs/nfs/sysfs.h
index 0fc80fb55b3e..51e0973f22d1 100644
--- a/fs/nfs/sysfs.h
+++ b/fs/nfs/sysfs.h
@@ -22,6 +22,8 @@ extern void nfs_sysfs_exit(void);
 void nfs_netns_sysfs_setup(struct nfs_net *netns, struct net *net);
 void nfs_netns_sysfs_destroy(struct nfs_net *netns);
 
+void nfs_sysfs_link_rpc_client(struct nfs_server *server,
+			struct rpc_clnt *clnt, const char *sysfs_prefix);
 void nfs_sysfs_add_server(struct nfs_server *s);
 void nfs_sysfs_move_server_to_sb(struct super_block *s);
 void nfs_sysfs_move_sb_to_server(struct nfs_server *s);
diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
index 770ef2cb5775..4ec718aa91f5 100644
--- a/include/linux/sunrpc/clnt.h
+++ b/include/linux/sunrpc/clnt.h
@@ -30,7 +30,13 @@
 #include <linux/sunrpc/xprtmultipath.h>
 
 struct rpc_inode;
-struct rpc_sysfs_client;
+struct rpc_sysfs_client {
+	struct kobject kobject;
+	struct net *net;
+	struct rpc_clnt *clnt;
+	struct rpc_xprt_switch *xprt_switch;
+};
+
 
 /*
  * The high-level client handle
diff --git a/net/sunrpc/sysfs.h b/net/sunrpc/sysfs.h
index 6620cebd1037..d2dd77a0a0e9 100644
--- a/net/sunrpc/sysfs.h
+++ b/net/sunrpc/sysfs.h
@@ -5,13 +5,6 @@
 #ifndef __SUNRPC_SYSFS_H
 #define __SUNRPC_SYSFS_H
 
-struct rpc_sysfs_client {
-	struct kobject kobject;
-	struct net *net;
-	struct rpc_clnt *clnt;
-	struct rpc_xprt_switch *xprt_switch;
-};
-
 struct rpc_sysfs_xprt_switch {
 	struct kobject kobject;
 	struct net *net;
-- 
2.39.2

[PATCH 5/9] NFS: add a sysfs link to the lockd rpc_client

[Benjamin Coddington]

After lockd is started, add a symlink for lockd's rpc_client under
NFS' superblock sysfs.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
---
 fs/lockd/clntlock.c        | 6 ++++++
 fs/nfs/client.c            | 1 +
 include/linux/lockd/bind.h | 2 ++
 3 files changed, 9 insertions(+)

diff --git a/fs/lockd/clntlock.c b/fs/lockd/clntlock.c
index a5bb3f721a9d..0340e10b5715 100644
--- a/fs/lockd/clntlock.c
+++ b/fs/lockd/clntlock.c
@@ -94,6 +94,12 @@ void nlmclnt_done(struct nlm_host *host)
 }
 EXPORT_SYMBOL_GPL(nlmclnt_done);
 
+struct rpc_clnt *nlmclnt_rpc_clnt(struct nlm_host *host)
+{
+	return host->h_rpcclnt;
+}
+EXPORT_SYMBOL_GPL(nlmclnt_rpc_clnt);
+
 /*
  * Queue up a lock for blocking so that the GRANTED request can see it
  */
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index de275f1fde92..eede8c28a56b 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -592,6 +592,7 @@ static int nfs_start_lockd(struct nfs_server *server)
 
 	server->nlm_host = host;
 	server->destroy = nfs_destroy_server;
+	nfs_sysfs_link_rpc_client(server, nlmclnt_rpc_clnt(host), NULL);
 	return 0;
 }
 
diff --git a/include/linux/lockd/bind.h b/include/linux/lockd/bind.h
index 3bc9f7410e21..c53c81242e72 100644
--- a/include/linux/lockd/bind.h
+++ b/include/linux/lockd/bind.h
@@ -20,6 +20,7 @@
 /* Dummy declarations */
 struct svc_rqst;
 struct rpc_task;
+struct rpc_clnt;
 
 /*
  * This is the set of functions for lockd->nfsd communication
@@ -56,6 +57,7 @@ struct nlmclnt_initdata {
 
 extern struct nlm_host *nlmclnt_init(const struct nlmclnt_initdata *nlm_init);
 extern void	nlmclnt_done(struct nlm_host *host);
+extern struct rpc_clnt *nlmclnt_rpc_clnt(struct nlm_host *host);
 
 /*
  * NLM client operations provide a means to modify RPC processing of NLM
-- 
2.39.2

[PATCH 6/9] NFS: add a sysfs link to the acl rpc_client

[Benjamin Coddington]

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
---
 fs/nfs/nfs3client.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/nfs/nfs3client.c b/fs/nfs/nfs3client.c
index 669cda757a5c..d6726b830c7c 100644
--- a/fs/nfs/nfs3client.c
+++ b/fs/nfs/nfs3client.c
@@ -4,6 +4,8 @@
 #include <linux/sunrpc/addr.h>
 #include "internal.h"
 #include "nfs3_fs.h"
+#include "netns.h"
+#include "sysfs.h"
 
 #ifdef CONFIG_NFS_V3_ACL
 static struct rpc_stat		nfsacl_rpcstat = { &nfsacl_program };
@@ -31,6 +33,8 @@ static void nfs_init_server_aclclient(struct nfs_server *server)
 	if (IS_ERR(server->client_acl))
 		goto out_noacl;
 
+	nfs_sysfs_link_rpc_client(server, server->client_acl, NULL);
+
 	/* No errors! Assume that Sun nfsacls are supported */
 	server->caps |= NFS_CAP_ACLS;
 	return;
-- 
2.39.2

[PATCH 7/9] NFS: add sysfs shutdown knob

[Benjamin Coddington]

Within each nfs_server sysfs tree, add an entry named "shutdown".  Writing
1 to this file will set the cl_shutdown bit on the rpc_clnt structs
associated with that mount.  If cl_shutdown is set, the task scheduler
immediately returns -EIO for new tasks.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
---
 fs/nfs/sysfs.c              | 46 +++++++++++++++++++++++++++++++++++++
 include/linux/nfs_fs_sb.h   |  1 +
 include/linux/sunrpc/clnt.h |  3 ++-
 net/sunrpc/clnt.c           |  5 ++++
 4 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/fs/nfs/sysfs.c b/fs/nfs/sysfs.c
index e1b5df7a3df5..09fde2719495 100644
--- a/fs/nfs/sysfs.c
+++ b/fs/nfs/sysfs.c
@@ -12,6 +12,7 @@
 #include <linux/string.h>
 #include <linux/nfs_fs.h>
 #include <linux/rcupdate.h>
+#include <linux/lockd/lockd.h>
 
 #include "nfs4_fs.h"
 #include "netns.h"
@@ -191,6 +192,50 @@ void nfs_netns_sysfs_destroy(struct nfs_net *netns)
 	}
 }
 
+static ssize_t
+shutdown_show(struct kobject *kobj, struct kobj_attribute *attr,
+				char *buf)
+{
+	struct nfs_server *server = container_of(kobj, struct nfs_server, kobj);
+	bool shutdown = server->flags & NFS_MOUNT_SHUTDOWN;
+	return sysfs_emit(buf, "%d\n", shutdown);
+}
+
+static ssize_t
+shutdown_store(struct kobject *kobj, struct kobj_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct nfs_server *server;
+	int ret, val;
+
+	server = container_of(kobj, struct nfs_server, kobj);
+
+	ret = kstrtoint(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	if (val != 1)
+		return -EINVAL;
+
+	/* already shut down? */
+	if (server->flags & NFS_MOUNT_SHUTDOWN)
+		goto out;
+
+	server->flags |= NFS_MOUNT_SHUTDOWN;
+	server->client->cl_shutdown = 1;
+	server->nfs_client->cl_rpcclient->cl_shutdown = 1;
+
+	if (!IS_ERR(server->client_acl))
+		server->client_acl->cl_shutdown = 1;
+
+	if (server->nlm_host)
+		server->nlm_host->h_rpcclnt->cl_shutdown = 1;
+out:
+	return count;
+}
+
+static struct kobj_attribute nfs_sysfs_attr_shutdown = __ATTR_RW(shutdown);
+
 #define RPC_CLIENT_NAME_SIZE 64
 
 void nfs_sysfs_link_rpc_client(struct nfs_server *server,
@@ -217,6 +262,7 @@ static void nfs_sysfs_sb_release(struct kobject *kobj)
 }
 
 static struct attribute *nfs_mp_attrs[] = {
+		&nfs_sysfs_attr_shutdown.attr,
         NULL,
 };
 
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index dee1664abca8..bc89496384ff 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -153,6 +153,7 @@ struct nfs_server {
 #define NFS_MOUNT_WRITE_EAGER		0x01000000
 #define NFS_MOUNT_WRITE_WAIT		0x02000000
 #define NFS_MOUNT_TRUNK_DISCOVERY	0x04000000
+#define NFS_MOUNT_SHUTDOWN			0x08000000
 
 	unsigned int		fattr_valid;	/* Valid attributes */
 	unsigned int		caps;		/* server capabilities */
diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
index 4ec718aa91f5..9f72c75a2056 100644
--- a/include/linux/sunrpc/clnt.h
+++ b/include/linux/sunrpc/clnt.h
@@ -63,7 +63,8 @@ struct rpc_clnt {
 				cl_discrtry : 1,/* disconnect before retry */
 				cl_noretranstimeo: 1,/* No retransmit timeouts */
 				cl_autobind : 1,/* use getport() */
-				cl_chatty   : 1;/* be verbose */
+				cl_chatty   : 1,/* be verbose */
+				cl_shutdown : 1;/* rpc immediate -EIO */
 
 	struct rpc_rtt *	cl_rtt;		/* RTO estimator data */
 	const struct rpc_timeout *cl_timeout;	/* Timeout strategy */
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 0b0b9f1eed46..3c5dca88a918 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1717,6 +1717,11 @@ call_start(struct rpc_task *task)
 
 	trace_rpc_request(task);
 
+	if (task->tk_client->cl_shutdown) {
+		rpc_call_rpcerror(task, -EIO);
+		return;
+	}
+
 	/* Increment call count (version might not be valid for ping) */
 	if (clnt->cl_program->version[clnt->cl_vers])
 		clnt->cl_program->version[clnt->cl_vers]->counts[idx]++;
-- 
2.39.2

[PATCH 8/9] NFS: Cleanup unused rpc_clnt variable

[Benjamin Coddington]

The root rpc_clnt is not used here, clean it up.

Fixes: 4dc73c679114 ("NFSv4: keep state manager thread active if swap is enabled")
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
---
 fs/nfs/nfs4state.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 2a0ca5c7f082..f8afd75e520d 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1205,10 +1205,6 @@ void nfs4_schedule_state_manager(struct nfs_client *clp)
 {
 	struct task_struct *task;
 	char buf[INET6_ADDRSTRLEN + sizeof("-manager") + 1];
-	struct rpc_clnt *cl = clp->cl_rpcclient;
-
-	while (cl != cl->cl_parent)
-		cl = cl->cl_parent;
 
 	set_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state);
 	if (test_and_set_bit(NFS4CLNT_MANAGER_AVAILABLE, &clp->cl_state) != 0) {
-- 
2.39.2

[PATCH 9/9] NFSv4: Clean up some shutdown loops

[Benjamin Coddington]

If a SEQUENCE call receives -EIO for a shutdown client, it will retry the
RPC call.  Instead of doing that for a shutdown client, just bail out.

Likewise, if the state manager decides to perform recovery for a shutdown
client, it will continuously retry.  As above, just bail out.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
---
 fs/nfs/nfs4proc.c  | 2 +-
 fs/nfs/nfs4state.c | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 40d749f29ed3..a36e35d885c3 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -9357,7 +9357,7 @@ static void nfs41_sequence_call_done(struct rpc_task *task, void *data)
 		return;
 
 	trace_nfs4_sequence(clp, task->tk_status);
-	if (task->tk_status < 0) {
+	if (task->tk_status < 0 && !task->tk_client->cl_shutdown) {
 		dprintk("%s ERROR %d\n", __func__, task->tk_status);
 		if (refcount_read(&clp->cl_count) == 1)
 			return;
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index f8afd75e520d..039a3b4ae565 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1206,6 +1206,9 @@ void nfs4_schedule_state_manager(struct nfs_client *clp)
 	struct task_struct *task;
 	char buf[INET6_ADDRSTRLEN + sizeof("-manager") + 1];
 
+	if (clp->cl_rpcclient->cl_shutdown)
+		return;
+
 	set_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state);
 	if (test_and_set_bit(NFS4CLNT_MANAGER_AVAILABLE, &clp->cl_state) != 0) {
 		wake_up_var(&clp->cl_state);
-- 
2.39.2

Re: [PATCH 0/9 RFC v2] NFS sysfs scaffolding

[Benjamin Coddington]

On 21 Apr 2023, at 13:08, Benjamin Coddington wrote:

> Here's another round of sysfs entries for each nfs_server, this time with a
> single use-case: a "shutdown" toggle that causes the basic rpc_clnt(s) to
> immediately fail tasks with -EIO.  It works well for the non pNFS cases to
> allow an unmount of a filesystem when the NFS server has gone away.
>
> I'm posting to gain potential NACKing, or to be redirected, or to serve as
> fodder for discussion at LSF.
>
> I'm thinking I'd like to toggle v4.2 things like READ_PLUS in here next, or
> other module-level options that maybe would be useful per-mount.
>
> Benjamin Coddington (9):
>   NFS: rename nfs_client_kset to nfs_kset
>   NFS: rename nfs_client_kobj to nfs_net_kobj
>   NFS: add superblock sysfs entries
>   NFS: Add sysfs links to sunrpc clients for nfs_clients
>   NFS: add a sysfs link to the lockd rpc_client
>   NFS: add a sysfs link to the acl rpc_client
>   NFS: add sysfs shutdown knob
>   NFS: Cleanup unused rpc_clnt variable

^^ whoops.. had the wrong patch in here.  I'll send a v3.

Ben

Re: [PATCH 0/9 RFC v2] NFS sysfs scaffolding

[Anna Schumaker]

Hi Ben,

On Fri, Apr 21, 2023 at 1:10 PM Benjamin Coddington <bcodding@redhat.com> wrote:
>
> Here's another round of sysfs entries for each nfs_server, this time with a
> single use-case: a "shutdown" toggle that causes the basic rpc_clnt(s) to
> immediately fail tasks with -EIO.  It works well for the non pNFS cases to
> allow an unmount of a filesystem when the NFS server has gone away.
>
> I'm posting to gain potential NACKing, or to be redirected, or to serve as
> fodder for discussion at LSF.
>
> I'm thinking I'd like to toggle v4.2 things like READ_PLUS in here next, or
> other module-level options that maybe would be useful per-mount.

I have a patch built on your v1 posting that implements this. I can
rebase on v2 (well, I guess it'll be v3 now) if you want to see it!

Anna

>
> Benjamin Coddington (9):
>   NFS: rename nfs_client_kset to nfs_kset
>   NFS: rename nfs_client_kobj to nfs_net_kobj
>   NFS: add superblock sysfs entries
>   NFS: Add sysfs links to sunrpc clients for nfs_clients
>   NFS: add a sysfs link to the lockd rpc_client
>   NFS: add a sysfs link to the acl rpc_client
>   NFS: add sysfs shutdown knob
>   NFS: Cleanup unused rpc_clnt variable
>   NFSv4: Clean up some shutdown loops
>
>  fs/lockd/clntlock.c         |   6 ++
>  fs/nfs/client.c             |  21 +++++
>  fs/nfs/nfs3client.c         |   4 +
>  fs/nfs/nfs4client.c         |   2 +
>  fs/nfs/nfs4proc.c           |   2 +-
>  fs/nfs/nfs4state.c          |   5 +-
>  fs/nfs/super.c              |   6 +-
>  fs/nfs/sysfs.c              | 148 +++++++++++++++++++++++++++++++++---
>  fs/nfs/sysfs.h              |   9 ++-
>  include/linux/lockd/bind.h  |   2 +
>  include/linux/nfs_fs_sb.h   |   3 +
>  include/linux/sunrpc/clnt.h |  11 ++-
>  net/sunrpc/clnt.c           |   5 ++
>  net/sunrpc/sysfs.h          |   7 --
>  14 files changed, 204 insertions(+), 27 deletions(-)
>
> --
> 2.39.2
>

Re: [PATCH 0/9 RFC v2] NFS sysfs scaffolding

[Benjamin Coddington]

On 21 Apr 2023, at 13:37, Anna Schumaker wrote:

> Hi Ben,
>
> On Fri, Apr 21, 2023 at 1:10 PM Benjamin Coddington <bcodding@redhat.com> wrote:
>>
>> Here's another round of sysfs entries for each nfs_server, this time with a
>> single use-case: a "shutdown" toggle that causes the basic rpc_clnt(s) to
>> immediately fail tasks with -EIO.  It works well for the non pNFS cases to
>> allow an unmount of a filesystem when the NFS server has gone away.
>>
>> I'm posting to gain potential NACKing, or to be redirected, or to serve as
>> fodder for discussion at LSF.
>>
>> I'm thinking I'd like to toggle v4.2 things like READ_PLUS in here next, or
>> other module-level options that maybe would be useful per-mount.
>
> I have a patch built on your v1 posting that implements this. I can
> rebase on v2 (well, I guess it'll be v3 now) if you want to see it!

Oh yeah, would love to see it!  I don't think anything changed in the first 6 patches.

Ben