Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1428 insertions, 0 deletions

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
new file mode 100644
index 000000000..05ae23657
--- /dev/null
+++ b/fs/nfs/super.c
@@ -0,0 +1,1428 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/fs/nfs/super.c
+ *
+ *  Copyright (C) 1992  Rick Sladkey
+ *
+ *  nfs superblock handling functions
+ *
+ *  Modularised by Alan Cox <alan@lxorguk.ukuu.org.uk>, while hacking some
+ *  experimental NFS changes. Modularisation taken straight from SYS5 fs.
+ *
+ *  Change to nfs_read_super() to permit NFS mounts to multi-homed hosts.
+ *  J.S.Peatfield@damtp.cam.ac.uk
+ *
+ *  Split from inode.c by David Howells <dhowells@redhat.com>
+ *
+ * - superblocks are indexed on server only - all inodes, dentries, etc. associated with a
+ *   particular server are held in the same superblock
+ * - NFS superblocks can have several effective roots to the dentry tree
+ * - directory type roots are spliced into the tree when a path from one root reaches the root
+ *   of another (see nfs_lookup())
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+
+#include <linux/time.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/stat.h>
+#include <linux/errno.h>
+#include <linux/unistd.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/addr.h>
+#include <linux/sunrpc/stats.h>
+#include <linux/sunrpc/metrics.h>
+#include <linux/sunrpc/xprtsock.h>
+#include <linux/sunrpc/xprtrdma.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_mount.h>
+#include <linux/nfs4_mount.h>
+#include <linux/lockd/bind.h>
+#include <linux/seq_file.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/vfs.h>
+#include <linux/inet.h>
+#include <linux/in6.h>
+#include <linux/slab.h>
+#include <net/ipv6.h>
+#include <linux/netdevice.h>
+#include <linux/nfs_xdr.h>
+#include <linux/magic.h>
+#include <linux/parser.h>
+#include <linux/nsproxy.h>
+#include <linux/rcupdate.h>
+
+#include <linux/uaccess.h>
+#include <linux/nfs_ssc.h>
+
+#include "nfs4_fs.h"
+#include "callback.h"
+#include "delegation.h"
+#include "iostat.h"
+#include "internal.h"
+#include "fscache.h"
+#include "nfs4session.h"
+#include "pnfs.h"
+#include "nfs.h"
+
+#define NFSDBG_FACILITY		NFSDBG_VFS
+
+const struct super_operations nfs_sops = {
+	.alloc_inode	= nfs_alloc_inode,
+	.free_inode	= nfs_free_inode,
+	.write_inode	= nfs_write_inode,
+	.drop_inode	= nfs_drop_inode,
+	.statfs		= nfs_statfs,
+	.evict_inode	= nfs_evict_inode,
+	.umount_begin	= nfs_umount_begin,
+	.show_options	= nfs_show_options,
+	.show_devname	= nfs_show_devname,
+	.show_path	= nfs_show_path,
+	.show_stats	= nfs_show_stats,
+};
+EXPORT_SYMBOL_GPL(nfs_sops);
+
+#ifdef CONFIG_NFS_V4_2
+static const struct nfs_ssc_client_ops nfs_ssc_clnt_ops_tbl = {
+	.sco_sb_deactive = nfs_sb_deactive,
+};
+#endif
+
+#if IS_ENABLED(CONFIG_NFS_V4)
+static int __init register_nfs4_fs(void)
+{
+	return register_filesystem(&nfs4_fs_type);
+}
+
+static void unregister_nfs4_fs(void)
+{
+	unregister_filesystem(&nfs4_fs_type);
+}
+#else
+static int __init register_nfs4_fs(void)
+{
+	return 0;
+}
+
+static void unregister_nfs4_fs(void)
+{
+}
+#endif
+
+#ifdef CONFIG_NFS_V4_2
+static void nfs_ssc_register_ops(void)
+{
+	nfs_ssc_register(&nfs_ssc_clnt_ops_tbl);
+}
+
+static void nfs_ssc_unregister_ops(void)
+{
+	nfs_ssc_unregister(&nfs_ssc_clnt_ops_tbl);
+}
+#endif /* CONFIG_NFS_V4_2 */
+
+static struct shrinker acl_shrinker = {
+	.count_objects	= nfs_access_cache_count,
+	.scan_objects	= nfs_access_cache_scan,
+	.seeks		= DEFAULT_SEEKS,
+};
+
+/*
+ * Register the NFS filesystems
+ */
+int __init register_nfs_fs(void)
+{
+	int ret;
+
+        ret = register_filesystem(&nfs_fs_type);
+	if (ret < 0)
+		goto error_0;
+
+	ret = register_nfs4_fs();
+	if (ret < 0)
+		goto error_1;
+
+	ret = nfs_register_sysctl();
+	if (ret < 0)
+		goto error_2;
+	ret = register_shrinker(&acl_shrinker, "nfs-acl");
+	if (ret < 0)
+		goto error_3;
+#ifdef CONFIG_NFS_V4_2
+	nfs_ssc_register_ops();
+#endif
+	return 0;
+error_3:
+	nfs_unregister_sysctl();
+error_2:
+	unregister_nfs4_fs();
+error_1:
+	unregister_filesystem(&nfs_fs_type);
+error_0:
+	return ret;
+}
+
+/*
+ * Unregister the NFS filesystems
+ */
+void __exit unregister_nfs_fs(void)
+{
+	unregister_shrinker(&acl_shrinker);
+	nfs_unregister_sysctl();
+	unregister_nfs4_fs();
+#ifdef CONFIG_NFS_V4_2
+	nfs_ssc_unregister_ops();
+#endif
+	unregister_filesystem(&nfs_fs_type);
+}
+
+bool nfs_sb_active(struct super_block *sb)
+{
+	struct nfs_server *server = NFS_SB(sb);
+
+	if (!atomic_inc_not_zero(&sb->s_active))
+		return false;
+	if (atomic_inc_return(&server->active) != 1)
+		atomic_dec(&sb->s_active);
+	return true;
+}
+EXPORT_SYMBOL_GPL(nfs_sb_active);
+
+void nfs_sb_deactive(struct super_block *sb)
+{
+	struct nfs_server *server = NFS_SB(sb);
+
+	if (atomic_dec_and_test(&server->active))
+		deactivate_super(sb);
+}
+EXPORT_SYMBOL_GPL(nfs_sb_deactive);
+
+static int __nfs_list_for_each_server(struct list_head *head,
+		int (*fn)(struct nfs_server *, void *),
+		void *data)
+{
+	struct nfs_server *server, *last = NULL;
+	int ret = 0;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(server, head, client_link) {
+		if (!(server->super && nfs_sb_active(server->super)))
+			continue;
+		rcu_read_unlock();
+		if (last)
+			nfs_sb_deactive(last->super);
+		last = server;
+		ret = fn(server, data);
+		if (ret)
+			goto out;
+		rcu_read_lock();
+	}
+	rcu_read_unlock();
+out:
+	if (last)
+		nfs_sb_deactive(last->super);
+	return ret;
+}
+
+int nfs_client_for_each_server(struct nfs_client *clp,
+		int (*fn)(struct nfs_server *, void *),
+		void *data)
+{
+	return __nfs_list_for_each_server(&clp->cl_superblocks, fn, data);
+}
+EXPORT_SYMBOL_GPL(nfs_client_for_each_server);
+
+/*
+ * Deliver file system statistics to userspace
+ */
+int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct nfs_server *server = NFS_SB(dentry->d_sb);
+	unsigned char blockbits;
+	unsigned long blockres;
+	struct nfs_fh *fh = NFS_FH(d_inode(dentry));
+	struct nfs_fsstat res;
+	int error = -ENOMEM;
+
+	res.fattr = nfs_alloc_fattr();
+	if (res.fattr == NULL)
+		goto out_err;
+
+	error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
+	if (unlikely(error == -ESTALE)) {
+		struct dentry *pd_dentry;
+
+		pd_dentry = dget_parent(dentry);
+		nfs_zap_caches(d_inode(pd_dentry));
+		dput(pd_dentry);
+	}
+	nfs_free_fattr(res.fattr);
+	if (error < 0)
+		goto out_err;
+
+	buf->f_type = NFS_SUPER_MAGIC;
+
+	/*
+	 * Current versions of glibc do not correctly handle the
+	 * case where f_frsize != f_bsize.  Eventually we want to
+	 * report the value of wtmult in this field.
+	 */
+	buf->f_frsize = dentry->d_sb->s_blocksize;
+
+	/*
+	 * On most *nix systems, f_blocks, f_bfree, and f_bavail
+	 * are reported in units of f_frsize.  Linux hasn't had
+	 * an f_frsize field in its statfs struct until recently,
+	 * thus historically Linux's sys_statfs reports these
+	 * fields in units of f_bsize.
+	 */
+	buf->f_bsize = dentry->d_sb->s_blocksize;
+	blockbits = dentry->d_sb->s_blocksize_bits;
+	blockres = (1 << blockbits) - 1;
+	buf->f_blocks = (res.tbytes + blockres) >> blockbits;
+	buf->f_bfree = (res.fbytes + blockres) >> blockbits;
+	buf->f_bavail = (res.abytes + blockres) >> blockbits;
+
+	buf->f_files = res.tfiles;
+	buf->f_ffree = res.afiles;
+
+	buf->f_namelen = server->namelen;
+
+	return 0;
+
+ out_err:
+	dprintk("%s: statfs error = %d\n", __func__, -error);
+	return error;
+}
+EXPORT_SYMBOL_GPL(nfs_statfs);
+
+/*
+ * Map the security flavour number to a name
+ */
+static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
+{
+	static const struct {
+		rpc_authflavor_t flavour;
+		const char *str;
+	} sec_flavours[NFS_AUTH_INFO_MAX_FLAVORS] = {
+		/* update NFS_AUTH_INFO_MAX_FLAVORS when this list changes! */
+		{ RPC_AUTH_NULL, "null" },
+		{ RPC_AUTH_UNIX, "sys" },
+		{ RPC_AUTH_GSS_KRB5, "krb5" },
+		{ RPC_AUTH_GSS_KRB5I, "krb5i" },
+		{ RPC_AUTH_GSS_KRB5P, "krb5p" },
+		{ RPC_AUTH_GSS_LKEY, "lkey" },
+		{ RPC_AUTH_GSS_LKEYI, "lkeyi" },
+		{ RPC_AUTH_GSS_LKEYP, "lkeyp" },
+		{ RPC_AUTH_GSS_SPKM, "spkm" },
+		{ RPC_AUTH_GSS_SPKMI, "spkmi" },
+		{ RPC_AUTH_GSS_SPKMP, "spkmp" },
+		{ UINT_MAX, "unknown" }
+	};
+	int i;
+
+	for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
+		if (sec_flavours[i].flavour == flavour)
+			break;
+	}
+	return sec_flavours[i].str;
+}
+
+static void nfs_show_mountd_netid(struct seq_file *m, struct nfs_server *nfss,
+				  int showdefaults)
+{
+	struct sockaddr *sap = (struct sockaddr *) &nfss->mountd_address;
+	char *proto = NULL;
+
+	switch (sap->sa_family) {
+	case AF_INET:
+		switch (nfss->mountd_protocol) {
+		case IPPROTO_UDP:
+			proto = RPCBIND_NETID_UDP;
+			break;
+		case IPPROTO_TCP:
+			proto = RPCBIND_NETID_TCP;
+			break;
+		}
+		break;
+	case AF_INET6:
+		switch (nfss->mountd_protocol) {
+		case IPPROTO_UDP:
+			proto = RPCBIND_NETID_UDP6;
+			break;
+		case IPPROTO_TCP:
+			proto = RPCBIND_NETID_TCP6;
+			break;
+		}
+		break;
+	}
+	if (proto || showdefaults)
+		seq_printf(m, ",mountproto=%s", proto ?: "auto");
+}
+
+static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
+				    int showdefaults)
+{
+	struct sockaddr *sap = (struct sockaddr *)&nfss->mountd_address;
+
+	if (nfss->flags & NFS_MOUNT_LEGACY_INTERFACE)
+		return;
+
+	switch (sap->sa_family) {
+	case AF_INET: {
+		struct sockaddr_in *sin = (struct sockaddr_in *)sap;
+		seq_printf(m, ",mountaddr=%pI4", &sin->sin_addr.s_addr);
+		break;
+	}
+	case AF_INET6: {
+		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
+		seq_printf(m, ",mountaddr=%pI6c", &sin6->sin6_addr);
+		break;
+	}
+	default:
+		if (showdefaults)
+			seq_puts(m, ",mountaddr=unspecified");
+	}
+
+	if (nfss->mountd_version || showdefaults)
+		seq_printf(m, ",mountvers=%u", nfss->mountd_version);
+	if ((nfss->mountd_port &&
+		nfss->mountd_port != (unsigned short)NFS_UNSPEC_PORT) ||
+		showdefaults)
+		seq_printf(m, ",mountport=%u", nfss->mountd_port);
+
+	nfs_show_mountd_netid(m, nfss, showdefaults);
+}
+
+#if IS_ENABLED(CONFIG_NFS_V4)
+static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
+				    int showdefaults)
+{
+	struct nfs_client *clp = nfss->nfs_client;
+
+	seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
+}
+#else
+static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
+				    int showdefaults)
+{
+}
+#endif
+
+static void nfs_show_nfs_version(struct seq_file *m,
+		unsigned int version,
+		unsigned int minorversion)
+{
+	seq_printf(m, ",vers=%u", version);
+	if (version == 4)
+		seq_printf(m, ".%u", minorversion);
+}
+
+/*
+ * Describe the mount options in force on this server representation
+ */
+static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
+				   int showdefaults)
+{
+	static const struct proc_nfs_info {
+		int flag;
+		const char *str;
+		const char *nostr;
+	} nfs_info[] = {
+		{ NFS_MOUNT_SOFT, ",soft", "" },
+		{ NFS_MOUNT_SOFTERR, ",softerr", "" },
+		{ NFS_MOUNT_SOFTREVAL, ",softreval", "" },
+		{ NFS_MOUNT_POSIX, ",posix", "" },
+		{ NFS_MOUNT_NOCTO, ",nocto", "" },
+		{ NFS_MOUNT_NOAC, ",noac", "" },
+		{ NFS_MOUNT_NONLM, ",nolock", "" },
+		{ NFS_MOUNT_NOACL, ",noacl", "" },
+		{ NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
+		{ NFS_MOUNT_UNSHARED, ",nosharecache", "" },
+		{ NFS_MOUNT_NORESVPORT, ",noresvport", "" },
+		{ 0, NULL, NULL }
+	};
+	const struct proc_nfs_info *nfs_infop;
+	struct nfs_client *clp = nfss->nfs_client;
+	u32 version = clp->rpc_ops->version;
+	int local_flock, local_fcntl;
+
+	nfs_show_nfs_version(m, version, clp->cl_minorversion);
+	seq_printf(m, ",rsize=%u", nfss->rsize);
+	seq_printf(m, ",wsize=%u", nfss->wsize);
+	if (nfss->bsize != 0)
+		seq_printf(m, ",bsize=%u", nfss->bsize);
+	seq_printf(m, ",namlen=%u", nfss->namelen);
+	if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
+		seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
+	if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
+		seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
+	if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
+		seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
+	if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
+		seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
+	if (!(nfss->flags & (NFS_MOUNT_SOFT|NFS_MOUNT_SOFTERR)))
+			seq_puts(m, ",hard");
+	for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
+		if (nfss->flags & nfs_infop->flag)
+			seq_puts(m, nfs_infop->str);
+		else
+			seq_puts(m, nfs_infop->nostr);
+	}
+	rcu_read_lock();
+	seq_printf(m, ",proto=%s",
+		   rpc_peeraddr2str(nfss->client, RPC_DISPLAY_NETID));
+	rcu_read_unlock();
+	if (clp->cl_nconnect > 0)
+		seq_printf(m, ",nconnect=%u", clp->cl_nconnect);
+	if (version == 4) {
+		if (clp->cl_max_connect > 1)
+			seq_printf(m, ",max_connect=%u", clp->cl_max_connect);
+		if (nfss->port != NFS_PORT)
+			seq_printf(m, ",port=%u", nfss->port);
+	} else
+		if (nfss->port)
+			seq_printf(m, ",port=%u", nfss->port);
+
+	seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
+	seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
+	seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
+
+	if (version != 4)
+		nfs_show_mountd_options(m, nfss, showdefaults);
+	else
+		nfs_show_nfsv4_options(m, nfss, showdefaults);
+
+	if (nfss->options & NFS_OPTION_FSCACHE)
+		seq_puts(m, ",fsc");
+
+	if (nfss->options & NFS_OPTION_MIGRATION)
+		seq_puts(m, ",migration");
+
+	if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) {
+		if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
+			seq_puts(m, ",lookupcache=none");
+		else
+			seq_puts(m, ",lookupcache=pos");
+	}
+
+	local_flock = nfss->flags & NFS_MOUNT_LOCAL_FLOCK;
+	local_fcntl = nfss->flags & NFS_MOUNT_LOCAL_FCNTL;
+
+	if (!local_flock && !local_fcntl)
+		seq_puts(m, ",local_lock=none");
+	else if (local_flock && local_fcntl)
+		seq_puts(m, ",local_lock=all");
+	else if (local_flock)
+		seq_puts(m, ",local_lock=flock");
+	else
+		seq_puts(m, ",local_lock=posix");
+
+	if (nfss->flags & NFS_MOUNT_WRITE_EAGER) {
+		if (nfss->flags & NFS_MOUNT_WRITE_WAIT)
+			seq_puts(m, ",write=wait");
+		else
+			seq_puts(m, ",write=eager");
+	}
+}
+
+/*
+ * Describe the mount options on this VFS mountpoint
+ */
+int nfs_show_options(struct seq_file *m, struct dentry *root)
+{
+	struct nfs_server *nfss = NFS_SB(root->d_sb);
+
+	nfs_show_mount_options(m, nfss, 0);
+
+	rcu_read_lock();
+	seq_printf(m, ",addr=%s",
+			rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
+							RPC_DISPLAY_ADDR));
+	rcu_read_unlock();
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nfs_show_options);
+
+#if IS_ENABLED(CONFIG_NFS_V4)
+static void show_lease(struct seq_file *m, struct nfs_server *server)
+{
+	struct nfs_client *clp = server->nfs_client;
+	unsigned long expire;
+
+	seq_printf(m, ",lease_time=%ld", clp->cl_lease_time / HZ);
+	expire = clp->cl_last_renewal + clp->cl_lease_time;
+	seq_printf(m, ",lease_expired=%ld",
+		   time_after(expire, jiffies) ?  0 : (jiffies - expire) / HZ);
+}
+#ifdef CONFIG_NFS_V4_1
+static void show_sessions(struct seq_file *m, struct nfs_server *server)
+{
+	if (nfs4_has_session(server->nfs_client))
+		seq_puts(m, ",sessions");
+}
+#else
+static void show_sessions(struct seq_file *m, struct nfs_server *server) {}
+#endif
+#endif
+
+#ifdef CONFIG_NFS_V4_1
+static void show_pnfs(struct seq_file *m, struct nfs_server *server)
+{
+	seq_printf(m, ",pnfs=");
+	if (server->pnfs_curr_ld)
+		seq_printf(m, "%s", server->pnfs_curr_ld->name);
+	else
+		seq_printf(m, "not configured");
+}
+
+static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
+{
+	if (nfss->nfs_client && nfss->nfs_client->cl_implid) {
+		struct nfs41_impl_id *impl_id = nfss->nfs_client->cl_implid;
+		seq_printf(m, "\n\timpl_id:\tname='%s',domain='%s',"
+			   "date='%llu,%u'",
+			   impl_id->name, impl_id->domain,
+			   impl_id->date.seconds, impl_id->date.nseconds);
+	}
+}
+#else
+#if IS_ENABLED(CONFIG_NFS_V4)
+static void show_pnfs(struct seq_file *m, struct nfs_server *server)
+{
+}
+#endif
+static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
+{
+}
+#endif
+
+int nfs_show_devname(struct seq_file *m, struct dentry *root)
+{
+	char *page = (char *) __get_free_page(GFP_KERNEL);
+	char *devname, *dummy;
+	int err = 0;
+	if (!page)
+		return -ENOMEM;
+	devname = nfs_path(&dummy, root, page, PAGE_SIZE, 0);
+	if (IS_ERR(devname))
+		err = PTR_ERR(devname);
+	else
+		seq_escape(m, devname, " \t\n\\");
+	free_page((unsigned long)page);
+	return err;
+}
+EXPORT_SYMBOL_GPL(nfs_show_devname);
+
+int nfs_show_path(struct seq_file *m, struct dentry *dentry)
+{
+	seq_puts(m, "/");
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nfs_show_path);
+
+/*
+ * Present statistical information for this VFS mountpoint
+ */
+int nfs_show_stats(struct seq_file *m, struct dentry *root)
+{
+	int i, cpu;
+	struct nfs_server *nfss = NFS_SB(root->d_sb);
+	struct rpc_auth *auth = nfss->client->cl_auth;
+	struct nfs_iostats totals = { };
+
+	seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
+
+	/*
+	 * Display all mount option settings
+	 */
+	seq_puts(m, "\n\topts:\t");
+	seq_puts(m, sb_rdonly(root->d_sb) ? "ro" : "rw");
+	seq_puts(m, root->d_sb->s_flags & SB_SYNCHRONOUS ? ",sync" : "");
+	seq_puts(m, root->d_sb->s_flags & SB_NOATIME ? ",noatime" : "");
+	seq_puts(m, root->d_sb->s_flags & SB_NODIRATIME ? ",nodiratime" : "");
+	nfs_show_mount_options(m, nfss, 1);
+
+	seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
+
+	show_implementation_id(m, nfss);
+
+	seq_puts(m, "\n\tcaps:\t");
+	seq_printf(m, "caps=0x%x", nfss->caps);
+	seq_printf(m, ",wtmult=%u", nfss->wtmult);
+	seq_printf(m, ",dtsize=%u", nfss->dtsize);
+	seq_printf(m, ",bsize=%u", nfss->bsize);
+	seq_printf(m, ",namlen=%u", nfss->namelen);
+
+#if IS_ENABLED(CONFIG_NFS_V4)
+	if (nfss->nfs_client->rpc_ops->version == 4) {
+		seq_puts(m, "\n\tnfsv4:\t");
+		seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
+		seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
+		seq_printf(m, ",bm2=0x%x", nfss->attr_bitmask[2]);
+		seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
+		show_sessions(m, nfss);
+		show_pnfs(m, nfss);
+		show_lease(m, nfss);
+	}
+#endif
+
+	/*
+	 * Display security flavor in effect for this mount
+	 */
+	seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
+	if (auth->au_flavor)
+		seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
+
+	/*
+	 * Display superblock I/O counters
+	 */
+	for_each_possible_cpu(cpu) {
+		struct nfs_iostats *stats;
+
+		preempt_disable();
+		stats = per_cpu_ptr(nfss->io_stats, cpu);
+
+		for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
+			totals.events[i] += stats->events[i];
+		for (i = 0; i < __NFSIOS_BYTESMAX; i++)
+			totals.bytes[i] += stats->bytes[i];
+#ifdef CONFIG_NFS_FSCACHE
+		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
+			totals.fscache[i] += stats->fscache[i];
+#endif
+
+		preempt_enable();
+	}
+
+	seq_puts(m, "\n\tevents:\t");
+	for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
+		seq_printf(m, "%lu ", totals.events[i]);
+	seq_puts(m, "\n\tbytes:\t");
+	for (i = 0; i < __NFSIOS_BYTESMAX; i++)
+		seq_printf(m, "%Lu ", totals.bytes[i]);
+#ifdef CONFIG_NFS_FSCACHE
+	if (nfss->options & NFS_OPTION_FSCACHE) {
+		seq_puts(m, "\n\tfsc:\t");
+		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
+			seq_printf(m, "%Lu ", totals.fscache[i]);
+	}
+#endif
+	seq_putc(m, '\n');
+
+	rpc_clnt_show_stats(m, nfss->client);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nfs_show_stats);
+
+/*
+ * Begin unmount by attempting to remove all automounted mountpoints we added
+ * in response to xdev traversals and referrals
+ */
+void nfs_umount_begin(struct super_block *sb)
+{
+	struct nfs_server *server;
+	struct rpc_clnt *rpc;
+
+	server = NFS_SB(sb);
+	/* -EIO all pending I/O */
+	rpc = server->client_acl;
+	if (!IS_ERR(rpc))
+		rpc_killall_tasks(rpc);
+	rpc = server->client;
+	if (!IS_ERR(rpc))
+		rpc_killall_tasks(rpc);
+}
+EXPORT_SYMBOL_GPL(nfs_umount_begin);
+
+/*
+ * Return true if 'match' is in auth_info or auth_info is empty.
+ * Return false otherwise.
+ */
+bool nfs_auth_info_match(const struct nfs_auth_info *auth_info,
+			 rpc_authflavor_t match)
+{
+	int i;
+
+	if (!auth_info->flavor_len)
+		return true;
+
+	for (i = 0; i < auth_info->flavor_len; i++) {
+		if (auth_info->flavors[i] == match)
+			return true;
+	}
+	return false;
+}
+EXPORT_SYMBOL_GPL(nfs_auth_info_match);
+
+/*
+ * Ensure that a specified authtype in ctx->auth_info is supported by
+ * the server. Returns 0 and sets ctx->selected_flavor if it's ok, and
+ * -EACCES if not.
+ */
+static int nfs_verify_authflavors(struct nfs_fs_context *ctx,
+				  rpc_authflavor_t *server_authlist,
+				  unsigned int count)
+{
+	rpc_authflavor_t flavor = RPC_AUTH_MAXFLAVOR;
+	bool found_auth_null = false;
+	unsigned int i;
+
+	/*
+	 * If the sec= mount option is used, the specified flavor or AUTH_NULL
+	 * must be in the list returned by the server.
+	 *
+	 * AUTH_NULL has a special meaning when it's in the server list - it
+	 * means that the server will ignore the rpc creds, so any flavor
+	 * can be used but still use the sec= that was specified.
+	 *
+	 * Note also that the MNT procedure in MNTv1 does not return a list
+	 * of supported security flavors. In this case, nfs_mount() fabricates
+	 * a security flavor list containing just AUTH_NULL.
+	 */
+	for (i = 0; i < count; i++) {
+		flavor = server_authlist[i];
+
+		if (nfs_auth_info_match(&ctx->auth_info, flavor))
+			goto out;
+
+		if (flavor == RPC_AUTH_NULL)
+			found_auth_null = true;
+	}
+
+	if (found_auth_null) {
+		flavor = ctx->auth_info.flavors[0];
+		goto out;
+	}
+
+	dfprintk(MOUNT,
+		 "NFS: specified auth flavors not supported by server\n");
+	return -EACCES;
+
+out:
+	ctx->selected_flavor = flavor;
+	dfprintk(MOUNT, "NFS: using auth flavor %u\n", ctx->selected_flavor);
+	return 0;
+}
+
+/*
+ * Use the remote server's MOUNT service to request the NFS file handle
+ * corresponding to the provided path.
+ */
+static int nfs_request_mount(struct fs_context *fc,
+			     struct nfs_fh *root_fh,
+			     rpc_authflavor_t *server_authlist,
+			     unsigned int *server_authlist_len)
+{
+	struct nfs_fs_context *ctx = nfs_fc2context(fc);
+	struct nfs_mount_request request = {
+		.sap		= &ctx->mount_server._address,
+		.dirpath	= ctx->nfs_server.export_path,
+		.protocol	= ctx->mount_server.protocol,
+		.fh		= root_fh,
+		.noresvport	= ctx->flags & NFS_MOUNT_NORESVPORT,
+		.auth_flav_len	= server_authlist_len,
+		.auth_flavs	= server_authlist,
+		.net		= fc->net_ns,
+	};
+	int status;
+
+	if (ctx->mount_server.version == 0) {
+		switch (ctx->version) {
+			default:
+				ctx->mount_server.version = NFS_MNT3_VERSION;
+				break;
+			case 2:
+				ctx->mount_server.version = NFS_MNT_VERSION;
+		}
+	}
+	request.version = ctx->mount_server.version;
+
+	if (ctx->mount_server.hostname)
+		request.hostname = ctx->mount_server.hostname;
+	else
+		request.hostname = ctx->nfs_server.hostname;
+
+	/*
+	 * Construct the mount server's address.
+	 */
+	if (ctx->mount_server.address.sa_family == AF_UNSPEC) {
+		memcpy(request.sap, &ctx->nfs_server._address,
+		       ctx->nfs_server.addrlen);
+		ctx->mount_server.addrlen = ctx->nfs_server.addrlen;
+	}
+	request.salen = ctx->mount_server.addrlen;
+	nfs_set_port(request.sap, &ctx->mount_server.port, 0);
+
+	/*
+	 * Now ask the mount server to map our export path
+	 * to a file handle.
+	 */
+	status = nfs_mount(&request, ctx->timeo, ctx->retrans);
+	if (status != 0) {
+		dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
+				request.hostname, status);
+		return status;
+	}
+
+	return 0;
+}
+
+static struct nfs_server *nfs_try_mount_request(struct fs_context *fc)
+{
+	struct nfs_fs_context *ctx = nfs_fc2context(fc);
+	int status;
+	unsigned int i;
+	bool tried_auth_unix = false;
+	bool auth_null_in_list = false;
+	struct nfs_server *server = ERR_PTR(-EACCES);
+	rpc_authflavor_t authlist[NFS_MAX_SECFLAVORS];
+	unsigned int authlist_len = ARRAY_SIZE(authlist);
+
+	status = nfs_request_mount(fc, ctx->mntfh, authlist, &authlist_len);
+	if (status)
+		return ERR_PTR(status);
+
+	/*
+	 * Was a sec= authflavor specified in the options? First, verify
+	 * whether the server supports it, and then just try to use it if so.
+	 */
+	if (ctx->auth_info.flavor_len > 0) {
+		status = nfs_verify_authflavors(ctx, authlist, authlist_len);
+		dfprintk(MOUNT, "NFS: using auth flavor %u\n",
+			 ctx->selected_flavor);
+		if (status)
+			return ERR_PTR(status);
+		return ctx->nfs_mod->rpc_ops->create_server(fc);
+	}
+
+	/*
+	 * No sec= option was provided. RFC 2623, section 2.7 suggests we
+	 * SHOULD prefer the flavor listed first. However, some servers list
+	 * AUTH_NULL first. Avoid ever choosing AUTH_NULL.
+	 */
+	for (i = 0; i < authlist_len; ++i) {
+		rpc_authflavor_t flavor;
+		struct rpcsec_gss_info info;
+
+		flavor = authlist[i];
+		switch (flavor) {
+		case RPC_AUTH_UNIX:
+			tried_auth_unix = true;
+			break;
+		case RPC_AUTH_NULL:
+			auth_null_in_list = true;
+			continue;
+		default:
+			if (rpcauth_get_gssinfo(flavor, &info) != 0)
+				continue;
+			break;
+		}
+		dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
+		ctx->selected_flavor = flavor;
+		server = ctx->nfs_mod->rpc_ops->create_server(fc);
+		if (!IS_ERR(server))
+			return server;
+	}
+
+	/*
+	 * Nothing we tried so far worked. At this point, give up if we've
+	 * already tried AUTH_UNIX or if the server's list doesn't contain
+	 * AUTH_NULL
+	 */
+	if (tried_auth_unix || !auth_null_in_list)
+		return server;
+
+	/* Last chance! Try AUTH_UNIX */
+	dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", RPC_AUTH_UNIX);
+	ctx->selected_flavor = RPC_AUTH_UNIX;
+	return ctx->nfs_mod->rpc_ops->create_server(fc);
+}
+
+int nfs_try_get_tree(struct fs_context *fc)
+{
+	struct nfs_fs_context *ctx = nfs_fc2context(fc);
+
+	if (ctx->need_mount)
+		ctx->server = nfs_try_mount_request(fc);
+	else
+		ctx->server = ctx->nfs_mod->rpc_ops->create_server(fc);
+
+	return nfs_get_tree_common(fc);
+}
+EXPORT_SYMBOL_GPL(nfs_try_get_tree);
+
+
+#define NFS_REMOUNT_CMP_FLAGMASK ~(NFS_MOUNT_INTR \
+		| NFS_MOUNT_SECURE \
+		| NFS_MOUNT_TCP \
+		| NFS_MOUNT_VER3 \
+		| NFS_MOUNT_KERBEROS \
+		| NFS_MOUNT_NONLM \
+		| NFS_MOUNT_BROKEN_SUID \
+		| NFS_MOUNT_STRICTLOCK \
+		| NFS_MOUNT_LEGACY_INTERFACE)
+
+#define NFS_MOUNT_CMP_FLAGMASK (NFS_REMOUNT_CMP_FLAGMASK & \
+		~(NFS_MOUNT_UNSHARED | NFS_MOUNT_NORESVPORT))
+
+static int
+nfs_compare_remount_data(struct nfs_server *nfss,
+			 struct nfs_fs_context *ctx)
+{
+	if ((ctx->flags ^ nfss->flags) & NFS_REMOUNT_CMP_FLAGMASK ||
+	    ctx->rsize != nfss->rsize ||
+	    ctx->wsize != nfss->wsize ||
+	    ctx->version != nfss->nfs_client->rpc_ops->version ||
+	    ctx->minorversion != nfss->nfs_client->cl_minorversion ||
+	    ctx->retrans != nfss->client->cl_timeout->to_retries ||
+	    !nfs_auth_info_match(&ctx->auth_info, nfss->client->cl_auth->au_flavor) ||
+	    ctx->acregmin != nfss->acregmin / HZ ||
+	    ctx->acregmax != nfss->acregmax / HZ ||
+	    ctx->acdirmin != nfss->acdirmin / HZ ||
+	    ctx->acdirmax != nfss->acdirmax / HZ ||
+	    ctx->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
+	    (ctx->options & NFS_OPTION_FSCACHE) != (nfss->options & NFS_OPTION_FSCACHE) ||
+	    ctx->nfs_server.port != nfss->port ||
+	    ctx->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
+	    !rpc_cmp_addr((struct sockaddr *)&ctx->nfs_server.address,
+			  (struct sockaddr *)&nfss->nfs_client->cl_addr))
+		return -EINVAL;
+
+	return 0;
+}
+
+int nfs_reconfigure(struct fs_context *fc)
+{
+	struct nfs_fs_context *ctx = nfs_fc2context(fc);
+	struct super_block *sb = fc->root->d_sb;
+	struct nfs_server *nfss = sb->s_fs_info;
+	int ret;
+
+	sync_filesystem(sb);
+
+	/*
+	 * Userspace mount programs that send binary options generally send
+	 * them populated with default values. We have no way to know which
+	 * ones were explicitly specified. Fall back to legacy behavior and
+	 * just return success.
+	 */
+	if (ctx->skip_reconfig_option_check)
+		return 0;
+
+	/*
+	 * noac is a special case. It implies -o sync, but that's not
+	 * necessarily reflected in the mtab options. reconfigure_super
+	 * will clear SB_SYNCHRONOUS if -o sync wasn't specified in the
+	 * remount options, so we have to explicitly reset it.
+	 */
+	if (ctx->flags & NFS_MOUNT_NOAC) {
+		fc->sb_flags |= SB_SYNCHRONOUS;
+		fc->sb_flags_mask |= SB_SYNCHRONOUS;
+	}
+
+	/* compare new mount options with old ones */
+	ret = nfs_compare_remount_data(nfss, ctx);
+	if (ret)
+		return ret;
+
+	return nfs_probe_server(nfss, NFS_FH(d_inode(fc->root)));
+}
+EXPORT_SYMBOL_GPL(nfs_reconfigure);
+
+/*
+ * Finish setting up an NFS superblock
+ */
+static void nfs_fill_super(struct super_block *sb, struct nfs_fs_context *ctx)
+{
+	struct nfs_server *server = NFS_SB(sb);
+
+	sb->s_blocksize_bits = 0;
+	sb->s_blocksize = 0;
+	sb->s_xattr = server->nfs_client->cl_nfs_mod->xattr;
+	sb->s_op = server->nfs_client->cl_nfs_mod->sops;
+	if (ctx->bsize)
+		sb->s_blocksize = nfs_block_size(ctx->bsize, &sb->s_blocksize_bits);
+
+	switch (server->nfs_client->rpc_ops->version) {
+	case 2:
+		sb->s_time_gran = 1000;
+		sb->s_time_min = 0;
+		sb->s_time_max = U32_MAX;
+		break;
+	case 3:
+		/*
+		 * The VFS shouldn't apply the umask to mode bits.
+		 * We will do so ourselves when necessary.
+		 */
+		sb->s_flags |= SB_POSIXACL;
+		sb->s_time_gran = 1;
+		sb->s_time_min = 0;
+		sb->s_time_max = U32_MAX;
+		sb->s_export_op = &nfs_export_ops;
+		break;
+	case 4:
+		sb->s_flags |= SB_POSIXACL;
+		sb->s_time_gran = 1;
+		sb->s_time_min = S64_MIN;
+		sb->s_time_max = S64_MAX;
+		if (server->caps & NFS_CAP_ATOMIC_OPEN_V1)
+			sb->s_export_op = &nfs_export_ops;
+		break;
+	}
+
+	sb->s_magic = NFS_SUPER_MAGIC;
+
+	/* We probably want something more informative here */
+	snprintf(sb->s_id, sizeof(sb->s_id),
+		 "%u:%u", MAJOR(sb->s_dev), MINOR(sb->s_dev));
+
+	if (sb->s_blocksize == 0)
+		sb->s_blocksize = nfs_block_bits(server->wsize,
+						 &sb->s_blocksize_bits);
+
+	nfs_super_set_maxbytes(sb, server->maxfilesize);
+	server->has_sec_mnt_opts = ctx->has_sec_mnt_opts;
+}
+
+static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b,
+				     const struct fs_context *fc)
+{
+	const struct nfs_server *a = s->s_fs_info;
+	const struct rpc_clnt *clnt_a = a->client;
+	const struct rpc_clnt *clnt_b = b->client;
+
+	if ((s->s_flags & NFS_SB_MASK) != (fc->sb_flags & NFS_SB_MASK))
+		goto Ebusy;
+	if (a->nfs_client != b->nfs_client)
+		goto Ebusy;
+	if ((a->flags ^ b->flags) & NFS_MOUNT_CMP_FLAGMASK)
+		goto Ebusy;
+	if (a->wsize != b->wsize)
+		goto Ebusy;
+	if (a->rsize != b->rsize)
+		goto Ebusy;
+	if (a->acregmin != b->acregmin)
+		goto Ebusy;
+	if (a->acregmax != b->acregmax)
+		goto Ebusy;
+	if (a->acdirmin != b->acdirmin)
+		goto Ebusy;
+	if (a->acdirmax != b->acdirmax)
+		goto Ebusy;
+	if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
+		goto Ebusy;
+	return 1;
+Ebusy:
+	return 0;
+}
+
+static int nfs_set_super(struct super_block *s, struct fs_context *fc)
+{
+	struct nfs_server *server = fc->s_fs_info;
+	int ret;
+
+	s->s_d_op = server->nfs_client->rpc_ops->dentry_ops;
+	ret = set_anon_super(s, server);
+	if (ret == 0)
+		server->s_dev = s->s_dev;
+	return ret;
+}
+
+static int nfs_compare_super_address(struct nfs_server *server1,
+				     struct nfs_server *server2)
+{
+	struct sockaddr *sap1, *sap2;
+	struct rpc_xprt *xprt1 = server1->client->cl_xprt;
+	struct rpc_xprt *xprt2 = server2->client->cl_xprt;
+
+	if (!net_eq(xprt1->xprt_net, xprt2->xprt_net))
+		return 0;
+
+	sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
+	sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
+
+	if (sap1->sa_family != sap2->sa_family)
+		return 0;
+
+	switch (sap1->sa_family) {
+	case AF_INET: {
+		struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
+		struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
+		if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
+			return 0;
+		if (sin1->sin_port != sin2->sin_port)
+			return 0;
+		break;
+	}
+	case AF_INET6: {
+		struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
+		struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
+		if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
+			return 0;
+		if (sin1->sin6_port != sin2->sin6_port)
+			return 0;
+		break;
+	}
+	default:
+		return 0;
+	}
+
+	return 1;
+}
+
+static int nfs_compare_userns(const struct nfs_server *old,
+		const struct nfs_server *new)
+{
+	const struct user_namespace *oldns = &init_user_ns;
+	const struct user_namespace *newns = &init_user_ns;
+
+	if (old->client && old->client->cl_cred)
+		oldns = old->client->cl_cred->user_ns;
+	if (new->client && new->client->cl_cred)
+		newns = new->client->cl_cred->user_ns;
+	if (oldns != newns)
+		return 0;
+	return 1;
+}
+
+static int nfs_compare_super(struct super_block *sb, struct fs_context *fc)
+{
+	struct nfs_server *server = fc->s_fs_info, *old = NFS_SB(sb);
+
+	if (!nfs_compare_super_address(old, server))
+		return 0;
+	/* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
+	if (old->flags & NFS_MOUNT_UNSHARED)
+		return 0;
+	if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
+		return 0;
+	if (!nfs_compare_userns(old, server))
+		return 0;
+	if ((old->has_sec_mnt_opts || fc->security) &&
+			security_sb_mnt_opts_compat(sb, fc->security))
+		return 0;
+	return nfs_compare_mount_options(sb, server, fc);
+}
+
+#ifdef CONFIG_NFS_FSCACHE
+static int nfs_get_cache_cookie(struct super_block *sb,
+				struct nfs_fs_context *ctx)
+{
+	struct nfs_server *nfss = NFS_SB(sb);
+	char *uniq = NULL;
+	int ulen = 0;
+
+	nfss->fscache = NULL;
+
+	if (!ctx)
+		return 0;
+
+	if (ctx->clone_data.sb) {
+		struct nfs_server *mnt_s = NFS_SB(ctx->clone_data.sb);
+		if (!(mnt_s->options & NFS_OPTION_FSCACHE))
+			return 0;
+		if (mnt_s->fscache_uniq) {
+			uniq = mnt_s->fscache_uniq;
+			ulen = strlen(uniq);
+		}
+	} else {
+		if (!(ctx->options & NFS_OPTION_FSCACHE))
+			return 0;
+		if (ctx->fscache_uniq) {
+			uniq = ctx->fscache_uniq;
+			ulen = strlen(ctx->fscache_uniq);
+		}
+	}
+
+	return nfs_fscache_get_super_cookie(sb, uniq, ulen);
+}
+#else
+static int nfs_get_cache_cookie(struct super_block *sb,
+				struct nfs_fs_context *ctx)
+{
+	return 0;
+}
+#endif
+
+int nfs_get_tree_common(struct fs_context *fc)
+{
+	struct nfs_fs_context *ctx = nfs_fc2context(fc);
+	struct super_block *s;
+	int (*compare_super)(struct super_block *, struct fs_context *) = nfs_compare_super;
+	struct nfs_server *server = ctx->server;
+	int error;
+
+	ctx->server = NULL;
+	if (IS_ERR(server))
+		return PTR_ERR(server);
+
+	if (server->flags & NFS_MOUNT_UNSHARED)
+		compare_super = NULL;
+
+	/* -o noac implies -o sync */
+	if (server->flags & NFS_MOUNT_NOAC)
+		fc->sb_flags |= SB_SYNCHRONOUS;
+
+	if (ctx->clone_data.sb)
+		if (ctx->clone_data.sb->s_flags & SB_SYNCHRONOUS)
+			fc->sb_flags |= SB_SYNCHRONOUS;
+
+	if (server->caps & NFS_CAP_SECURITY_LABEL)
+		fc->lsm_flags |= SECURITY_LSM_NATIVE_LABELS;
+
+	/* Get a superblock - note that we may end up sharing one that already exists */
+	fc->s_fs_info = server;
+	s = sget_fc(fc, compare_super, nfs_set_super);
+	fc->s_fs_info = NULL;
+	if (IS_ERR(s)) {
+		error = PTR_ERR(s);
+		nfs_errorf(fc, "NFS: Couldn't get superblock");
+		goto out_err_nosb;
+	}
+
+	if (s->s_fs_info != server) {
+		nfs_free_server(server);
+		server = NULL;
+	} else {
+		error = super_setup_bdi_name(s, "%u:%u", MAJOR(server->s_dev),
+					     MINOR(server->s_dev));
+		if (error)
+			goto error_splat_super;
+		s->s_bdi->io_pages = server->rpages;
+		server->super = s;
+	}
+
+	if (!s->s_root) {
+		unsigned bsize = ctx->clone_data.inherited_bsize;
+		/* initial superblock/root creation */
+		nfs_fill_super(s, ctx);
+		if (bsize) {
+			s->s_blocksize_bits = bsize;
+			s->s_blocksize = 1U << bsize;
+		}
+		error = nfs_get_cache_cookie(s, ctx);
+		if (error < 0)
+			goto error_splat_super;
+	}
+
+	error = nfs_get_root(s, fc);
+	if (error < 0) {
+		nfs_errorf(fc, "NFS: Couldn't get root dentry");
+		goto error_splat_super;
+	}
+
+	s->s_flags |= SB_ACTIVE;
+	error = 0;
+
+out:
+	return error;
+
+out_err_nosb:
+	nfs_free_server(server);
+	goto out;
+error_splat_super:
+	deactivate_locked_super(s);
+	goto out;
+}
+
+/*
+ * Destroy an NFS2/3 superblock
+ */
+void nfs_kill_super(struct super_block *s)
+{
+	struct nfs_server *server = NFS_SB(s);
+	dev_t dev = s->s_dev;
+
+	generic_shutdown_super(s);
+
+	nfs_fscache_release_super_cookie(s);
+
+	nfs_free_server(server);
+	free_anon_bdev(dev);
+}
+EXPORT_SYMBOL_GPL(nfs_kill_super);
+
+#if IS_ENABLED(CONFIG_NFS_V4)
+
+/*
+ * NFS v4 module parameters need to stay in the
+ * NFS client for backwards compatibility
+ */
+unsigned int nfs_callback_set_tcpport;
+unsigned short nfs_callback_nr_threads;
+/* Default cache timeout is 10 minutes */
+unsigned int nfs_idmap_cache_timeout = 600;
+/* Turn off NFSv4 uid/gid mapping when using AUTH_SYS */
+bool nfs4_disable_idmapping = true;
+unsigned short max_session_slots = NFS4_DEF_SLOT_TABLE_SIZE;
+unsigned short max_session_cb_slots = NFS4_DEF_CB_SLOT_TABLE_SIZE;
+unsigned short send_implementation_id = 1;
+char nfs4_client_id_uniquifier[NFS4_CLIENT_ID_UNIQ_LEN] = "";
+bool recover_lost_locks = false;
+
+EXPORT_SYMBOL_GPL(nfs_callback_nr_threads);
+EXPORT_SYMBOL_GPL(nfs_callback_set_tcpport);
+EXPORT_SYMBOL_GPL(nfs_idmap_cache_timeout);
+EXPORT_SYMBOL_GPL(nfs4_disable_idmapping);
+EXPORT_SYMBOL_GPL(max_session_slots);
+EXPORT_SYMBOL_GPL(max_session_cb_slots);
+EXPORT_SYMBOL_GPL(send_implementation_id);
+EXPORT_SYMBOL_GPL(nfs4_client_id_uniquifier);
+EXPORT_SYMBOL_GPL(recover_lost_locks);
+
+#define NFS_CALLBACK_MAXPORTNR (65535U)
+
+static int param_set_portnr(const char *val, const struct kernel_param *kp)
+{
+	unsigned long num;
+	int ret;
+
+	if (!val)
+		return -EINVAL;
+	ret = kstrtoul(val, 0, &num);
+	if (ret || num > NFS_CALLBACK_MAXPORTNR)
+		return -EINVAL;
+	*((unsigned int *)kp->arg) = num;
+	return 0;
+}
+static const struct kernel_param_ops param_ops_portnr = {
+	.set = param_set_portnr,
+	.get = param_get_uint,
+};
+#define param_check_portnr(name, p) __param_check(name, p, unsigned int)
+
+module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644);
+module_param_named(callback_nr_threads, nfs_callback_nr_threads, ushort, 0644);
+MODULE_PARM_DESC(callback_nr_threads, "Number of threads that will be "
+		"assigned to the NFSv4 callback channels.");
+module_param(nfs_idmap_cache_timeout, int, 0644);
+module_param(nfs4_disable_idmapping, bool, 0644);
+module_param_string(nfs4_unique_id, nfs4_client_id_uniquifier,
+			NFS4_CLIENT_ID_UNIQ_LEN, 0600);
+MODULE_PARM_DESC(nfs4_disable_idmapping,
+		"Turn off NFSv4 idmapping when using 'sec=sys'");
+module_param(max_session_slots, ushort, 0644);
+MODULE_PARM_DESC(max_session_slots, "Maximum number of outstanding NFSv4.1 "
+		"requests the client will negotiate");
+module_param(max_session_cb_slots, ushort, 0644);
+MODULE_PARM_DESC(max_session_cb_slots, "Maximum number of parallel NFSv4.1 "
+		"callbacks the client will process for a given server");
+module_param(send_implementation_id, ushort, 0644);
+MODULE_PARM_DESC(send_implementation_id,
+		"Send implementation ID with NFSv4.1 exchange_id");
+MODULE_PARM_DESC(nfs4_unique_id, "nfs_client_id4 uniquifier string");
+
+module_param(recover_lost_locks, bool, 0644);
+MODULE_PARM_DESC(recover_lost_locks,
+		 "If the server reports that a lock might be lost, "
+		 "try to recover it risking data corruption.");
+
+
+#endif /* CONFIG_NFS_V4 */