Adding upstream version 5.10.209.upstream/5.10.209

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

1 files changed, 2169 insertions, 0 deletions

diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
new file mode 100644
index 000000000..83c4e6883
--- /dev/null
+++ b/fs/nfsd/nfs4recover.c
@@ -0,0 +1,2169 @@
+/*
+*  Copyright (c) 2004 The Regents of the University of Michigan.
+*  Copyright (c) 2012 Jeff Layton <jlayton@redhat.com>
+*  All rights reserved.
+*
+*  Andy Adamson <andros@citi.umich.edu>
+*
+*  Redistribution and use in source and binary forms, with or without
+*  modification, are permitted provided that the following conditions
+*  are met:
+*
+*  1. Redistributions of source code must retain the above copyright
+*     notice, this list of conditions and the following disclaimer.
+*  2. Redistributions in binary form must reproduce the above copyright
+*     notice, this list of conditions and the following disclaimer in the
+*     documentation and/or other materials provided with the distribution.
+*  3. Neither the name of the University nor the names of its
+*     contributors may be used to endorse or promote products derived
+*     from this software without specific prior written permission.
+*
+*  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+*  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+*  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+*  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+*  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+*  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+*  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+*  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+*  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+*  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+*  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+*/
+
+#include <crypto/hash.h>
+#include <linux/file.h>
+#include <linux/slab.h>
+#include <linux/namei.h>
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <net/net_namespace.h>
+#include <linux/sunrpc/rpc_pipe_fs.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/nfsd/cld.h>
+
+#include "nfsd.h"
+#include "state.h"
+#include "vfs.h"
+#include "netns.h"
+
+#define NFSDDBG_FACILITY                NFSDDBG_PROC
+
+/* Declarations */
+struct nfsd4_client_tracking_ops {
+	int (*init)(struct net *);
+	void (*exit)(struct net *);
+	void (*create)(struct nfs4_client *);
+	void (*remove)(struct nfs4_client *);
+	int (*check)(struct nfs4_client *);
+	void (*grace_done)(struct nfsd_net *);
+	uint8_t version;
+	size_t msglen;
+};
+
+static const struct nfsd4_client_tracking_ops nfsd4_cld_tracking_ops;
+static const struct nfsd4_client_tracking_ops nfsd4_cld_tracking_ops_v2;
+
+/* Globals */
+static char user_recovery_dirname[PATH_MAX] = "/var/lib/nfs/v4recovery";
+
+static int
+nfs4_save_creds(const struct cred **original_creds)
+{
+	struct cred *new;
+
+	new = prepare_creds();
+	if (!new)
+		return -ENOMEM;
+
+	new->fsuid = GLOBAL_ROOT_UID;
+	new->fsgid = GLOBAL_ROOT_GID;
+	*original_creds = override_creds(new);
+	put_cred(new);
+	return 0;
+}
+
+static void
+nfs4_reset_creds(const struct cred *original)
+{
+	revert_creds(original);
+}
+
+static void
+md5_to_hex(char *out, char *md5)
+{
+	int i;
+
+	for (i=0; i<16; i++) {
+		unsigned char c = md5[i];
+
+		*out++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
+		*out++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
+	}
+	*out = '\0';
+}
+
+static int
+nfs4_make_rec_clidname(char *dname, const struct xdr_netobj *clname)
+{
+	struct xdr_netobj cksum;
+	struct crypto_shash *tfm;
+	int status;
+
+	dprintk("NFSD: nfs4_make_rec_clidname for %.*s\n",
+			clname->len, clname->data);
+	tfm = crypto_alloc_shash("md5", 0, 0);
+	if (IS_ERR(tfm)) {
+		status = PTR_ERR(tfm);
+		goto out_no_tfm;
+	}
+
+	cksum.len = crypto_shash_digestsize(tfm);
+	cksum.data = kmalloc(cksum.len, GFP_KERNEL);
+	if (cksum.data == NULL) {
+		status = -ENOMEM;
+ 		goto out;
+	}
+
+	status = crypto_shash_tfm_digest(tfm, clname->data, clname->len,
+					 cksum.data);
+	if (status)
+		goto out;
+
+	md5_to_hex(dname, cksum.data);
+
+	status = 0;
+out:
+	kfree(cksum.data);
+	crypto_free_shash(tfm);
+out_no_tfm:
+	return status;
+}
+
+/*
+ * If we had an error generating the recdir name for the legacy tracker
+ * then warn the admin. If the error doesn't appear to be transient,
+ * then disable recovery tracking.
+ */
+static void
+legacy_recdir_name_error(struct nfs4_client *clp, int error)
+{
+	printk(KERN_ERR "NFSD: unable to generate recoverydir "
+			"name (%d).\n", error);
+
+	/*
+	 * if the algorithm just doesn't exist, then disable the recovery
+	 * tracker altogether. The crypto libs will generally return this if
+	 * FIPS is enabled as well.
+	 */
+	if (error == -ENOENT) {
+		printk(KERN_ERR "NFSD: disabling legacy clientid tracking. "
+			"Reboot recovery will not function correctly!\n");
+		nfsd4_client_tracking_exit(clp->net);
+	}
+}
+
+static void
+__nfsd4_create_reclaim_record_grace(struct nfs4_client *clp,
+		const char *dname, int len, struct nfsd_net *nn)
+{
+	struct xdr_netobj name;
+	struct xdr_netobj princhash = { .len = 0, .data = NULL };
+	struct nfs4_client_reclaim *crp;
+
+	name.data = kmemdup(dname, len, GFP_KERNEL);
+	if (!name.data) {
+		dprintk("%s: failed to allocate memory for name.data!\n",
+			__func__);
+		return;
+	}
+	name.len = len;
+	crp = nfs4_client_to_reclaim(name, princhash, nn);
+	if (!crp) {
+		kfree(name.data);
+		return;
+	}
+	crp->cr_clp = clp;
+}
+
+static void
+nfsd4_create_clid_dir(struct nfs4_client *clp)
+{
+	const struct cred *original_cred;
+	char dname[HEXDIR_LEN];
+	struct dentry *dir, *dentry;
+	int status;
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+
+	if (test_and_set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
+		return;
+	if (!nn->rec_file)
+		return;
+
+	status = nfs4_make_rec_clidname(dname, &clp->cl_name);
+	if (status)
+		return legacy_recdir_name_error(clp, status);
+
+	status = nfs4_save_creds(&original_cred);
+	if (status < 0)
+		return;
+
+	status = mnt_want_write_file(nn->rec_file);
+	if (status)
+		goto out_creds;
+
+	dir = nn->rec_file->f_path.dentry;
+	/* lock the parent */
+	inode_lock(d_inode(dir));
+
+	dentry = lookup_one_len(dname, dir, HEXDIR_LEN-1);
+	if (IS_ERR(dentry)) {
+		status = PTR_ERR(dentry);
+		goto out_unlock;
+	}
+	if (d_really_is_positive(dentry))
+		/*
+		 * In the 4.1 case, where we're called from
+		 * reclaim_complete(), records from the previous reboot
+		 * may still be left, so this is OK.
+		 *
+		 * In the 4.0 case, we should never get here; but we may
+		 * as well be forgiving and just succeed silently.
+		 */
+		goto out_put;
+	status = vfs_mkdir(d_inode(dir), dentry, S_IRWXU);
+out_put:
+	dput(dentry);
+out_unlock:
+	inode_unlock(d_inode(dir));
+	if (status == 0) {
+		if (nn->in_grace)
+			__nfsd4_create_reclaim_record_grace(clp, dname,
+					HEXDIR_LEN, nn);
+		vfs_fsync(nn->rec_file, 0);
+	} else {
+		printk(KERN_ERR "NFSD: failed to write recovery record"
+				" (err %d); please check that %s exists"
+				" and is writeable", status,
+				user_recovery_dirname);
+	}
+	mnt_drop_write_file(nn->rec_file);
+out_creds:
+	nfs4_reset_creds(original_cred);
+}
+
+typedef int (recdir_func)(struct dentry *, struct dentry *, struct nfsd_net *);
+
+struct name_list {
+	char name[HEXDIR_LEN];
+	struct list_head list;
+};
+
+struct nfs4_dir_ctx {
+	struct dir_context ctx;
+	struct list_head names;
+};
+
+static int
+nfsd4_build_namelist(struct dir_context *__ctx, const char *name, int namlen,
+		loff_t offset, u64 ino, unsigned int d_type)
+{
+	struct nfs4_dir_ctx *ctx =
+		container_of(__ctx, struct nfs4_dir_ctx, ctx);
+	struct name_list *entry;
+
+	if (namlen != HEXDIR_LEN - 1)
+		return 0;
+	entry = kmalloc(sizeof(struct name_list), GFP_KERNEL);
+	if (entry == NULL)
+		return -ENOMEM;
+	memcpy(entry->name, name, HEXDIR_LEN - 1);
+	entry->name[HEXDIR_LEN - 1] = '\0';
+	list_add(&entry->list, &ctx->names);
+	return 0;
+}
+
+static int
+nfsd4_list_rec_dir(recdir_func *f, struct nfsd_net *nn)
+{
+	const struct cred *original_cred;
+	struct dentry *dir = nn->rec_file->f_path.dentry;
+	struct nfs4_dir_ctx ctx = {
+		.ctx.actor = nfsd4_build_namelist,
+		.names = LIST_HEAD_INIT(ctx.names)
+	};
+	struct name_list *entry, *tmp;
+	int status;
+
+	status = nfs4_save_creds(&original_cred);
+	if (status < 0)
+		return status;
+
+	status = vfs_llseek(nn->rec_file, 0, SEEK_SET);
+	if (status < 0) {
+		nfs4_reset_creds(original_cred);
+		return status;
+	}
+
+	status = iterate_dir(nn->rec_file, &ctx.ctx);
+	inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
+
+	list_for_each_entry_safe(entry, tmp, &ctx.names, list) {
+		if (!status) {
+			struct dentry *dentry;
+			dentry = lookup_one_len(entry->name, dir, HEXDIR_LEN-1);
+			if (IS_ERR(dentry)) {
+				status = PTR_ERR(dentry);
+				break;
+			}
+			status = f(dir, dentry, nn);
+			dput(dentry);
+		}
+		list_del(&entry->list);
+		kfree(entry);
+	}
+	inode_unlock(d_inode(dir));
+	nfs4_reset_creds(original_cred);
+
+	list_for_each_entry_safe(entry, tmp, &ctx.names, list) {
+		dprintk("NFSD: %s. Left entry %s\n", __func__, entry->name);
+		list_del(&entry->list);
+		kfree(entry);
+	}
+	return status;
+}
+
+static int
+nfsd4_unlink_clid_dir(char *name, int namlen, struct nfsd_net *nn)
+{
+	struct dentry *dir, *dentry;
+	int status;
+
+	dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
+
+	dir = nn->rec_file->f_path.dentry;
+	inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
+	dentry = lookup_one_len(name, dir, namlen);
+	if (IS_ERR(dentry)) {
+		status = PTR_ERR(dentry);
+		goto out_unlock;
+	}
+	status = -ENOENT;
+	if (d_really_is_negative(dentry))
+		goto out;
+	status = vfs_rmdir(d_inode(dir), dentry);
+out:
+	dput(dentry);
+out_unlock:
+	inode_unlock(d_inode(dir));
+	return status;
+}
+
+static void
+__nfsd4_remove_reclaim_record_grace(const char *dname, int len,
+		struct nfsd_net *nn)
+{
+	struct xdr_netobj name;
+	struct nfs4_client_reclaim *crp;
+
+	name.data = kmemdup(dname, len, GFP_KERNEL);
+	if (!name.data) {
+		dprintk("%s: failed to allocate memory for name.data!\n",
+			__func__);
+		return;
+	}
+	name.len = len;
+	crp = nfsd4_find_reclaim_client(name, nn);
+	kfree(name.data);
+	if (crp)
+		nfs4_remove_reclaim_record(crp, nn);
+}
+
+static void
+nfsd4_remove_clid_dir(struct nfs4_client *clp)
+{
+	const struct cred *original_cred;
+	char dname[HEXDIR_LEN];
+	int status;
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+
+	if (!nn->rec_file || !test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
+		return;
+
+	status = nfs4_make_rec_clidname(dname, &clp->cl_name);
+	if (status)
+		return legacy_recdir_name_error(clp, status);
+
+	status = mnt_want_write_file(nn->rec_file);
+	if (status)
+		goto out;
+	clear_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
+
+	status = nfs4_save_creds(&original_cred);
+	if (status < 0)
+		goto out_drop_write;
+
+	status = nfsd4_unlink_clid_dir(dname, HEXDIR_LEN-1, nn);
+	nfs4_reset_creds(original_cred);
+	if (status == 0) {
+		vfs_fsync(nn->rec_file, 0);
+		if (nn->in_grace)
+			__nfsd4_remove_reclaim_record_grace(dname,
+					HEXDIR_LEN, nn);
+	}
+out_drop_write:
+	mnt_drop_write_file(nn->rec_file);
+out:
+	if (status)
+		printk("NFSD: Failed to remove expired client state directory"
+				" %.*s\n", HEXDIR_LEN, dname);
+}
+
+static int
+purge_old(struct dentry *parent, struct dentry *child, struct nfsd_net *nn)
+{
+	int status;
+	struct xdr_netobj name;
+
+	if (child->d_name.len != HEXDIR_LEN - 1) {
+		printk("%s: illegal name %pd in recovery directory\n",
+				__func__, child);
+		/* Keep trying; maybe the others are OK: */
+		return 0;
+	}
+	name.data = kmemdup_nul(child->d_name.name, child->d_name.len, GFP_KERNEL);
+	if (!name.data) {
+		dprintk("%s: failed to allocate memory for name.data!\n",
+			__func__);
+		goto out;
+	}
+	name.len = HEXDIR_LEN;
+	if (nfs4_has_reclaimed_state(name, nn))
+		goto out_free;
+
+	status = vfs_rmdir(d_inode(parent), child);
+	if (status)
+		printk("failed to remove client recovery directory %pd\n",
+				child);
+out_free:
+	kfree(name.data);
+out:
+	/* Keep trying, success or failure: */
+	return 0;
+}
+
+static void
+nfsd4_recdir_purge_old(struct nfsd_net *nn)
+{
+	int status;
+
+	nn->in_grace = false;
+	if (!nn->rec_file)
+		return;
+	status = mnt_want_write_file(nn->rec_file);
+	if (status)
+		goto out;
+	status = nfsd4_list_rec_dir(purge_old, nn);
+	if (status == 0)
+		vfs_fsync(nn->rec_file, 0);
+	mnt_drop_write_file(nn->rec_file);
+out:
+	nfs4_release_reclaim(nn);
+	if (status)
+		printk("nfsd4: failed to purge old clients from recovery"
+			" directory %pD\n", nn->rec_file);
+}
+
+static int
+load_recdir(struct dentry *parent, struct dentry *child, struct nfsd_net *nn)
+{
+	struct xdr_netobj name;
+	struct xdr_netobj princhash = { .len = 0, .data = NULL };
+
+	if (child->d_name.len != HEXDIR_LEN - 1) {
+		printk("%s: illegal name %pd in recovery directory\n",
+				__func__, child);
+		/* Keep trying; maybe the others are OK: */
+		return 0;
+	}
+	name.data = kmemdup_nul(child->d_name.name, child->d_name.len, GFP_KERNEL);
+	if (!name.data) {
+		dprintk("%s: failed to allocate memory for name.data!\n",
+			__func__);
+		goto out;
+	}
+	name.len = HEXDIR_LEN;
+	if (!nfs4_client_to_reclaim(name, princhash, nn))
+		kfree(name.data);
+out:
+	return 0;
+}
+
+static int
+nfsd4_recdir_load(struct net *net) {
+	int status;
+	struct nfsd_net *nn =  net_generic(net, nfsd_net_id);
+
+	if (!nn->rec_file)
+		return 0;
+
+	status = nfsd4_list_rec_dir(load_recdir, nn);
+	if (status)
+		printk("nfsd4: failed loading clients from recovery"
+			" directory %pD\n", nn->rec_file);
+	return status;
+}
+
+/*
+ * Hold reference to the recovery directory.
+ */
+
+static int
+nfsd4_init_recdir(struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	const struct cred *original_cred;
+	int status;
+
+	printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
+			user_recovery_dirname);
+
+	BUG_ON(nn->rec_file);
+
+	status = nfs4_save_creds(&original_cred);
+	if (status < 0) {
+		printk("NFSD: Unable to change credentials to find recovery"
+		       " directory: error %d\n",
+		       status);
+		return status;
+	}
+
+	nn->rec_file = filp_open(user_recovery_dirname, O_RDONLY | O_DIRECTORY, 0);
+	if (IS_ERR(nn->rec_file)) {
+		printk("NFSD: unable to find recovery directory %s\n",
+				user_recovery_dirname);
+		status = PTR_ERR(nn->rec_file);
+		nn->rec_file = NULL;
+	}
+
+	nfs4_reset_creds(original_cred);
+	if (!status)
+		nn->in_grace = true;
+	return status;
+}
+
+static void
+nfsd4_shutdown_recdir(struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	if (!nn->rec_file)
+		return;
+	fput(nn->rec_file);
+	nn->rec_file = NULL;
+}
+
+static int
+nfs4_legacy_state_init(struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	int i;
+
+	nn->reclaim_str_hashtbl = kmalloc_array(CLIENT_HASH_SIZE,
+						sizeof(struct list_head),
+						GFP_KERNEL);
+	if (!nn->reclaim_str_hashtbl)
+		return -ENOMEM;
+
+	for (i = 0; i < CLIENT_HASH_SIZE; i++)
+		INIT_LIST_HEAD(&nn->reclaim_str_hashtbl[i]);
+	nn->reclaim_str_hashtbl_size = 0;
+
+	return 0;
+}
+
+static void
+nfs4_legacy_state_shutdown(struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	kfree(nn->reclaim_str_hashtbl);
+}
+
+static int
+nfsd4_load_reboot_recovery_data(struct net *net)
+{
+	int status;
+
+	status = nfsd4_init_recdir(net);
+	if (status)
+		return status;
+
+	status = nfsd4_recdir_load(net);
+	if (status)
+		nfsd4_shutdown_recdir(net);
+
+	return status;
+}
+
+static int
+nfsd4_legacy_tracking_init(struct net *net)
+{
+	int status;
+
+	/* XXX: The legacy code won't work in a container */
+	if (net != &init_net) {
+		pr_warn("NFSD: attempt to initialize legacy client tracking in a container ignored.\n");
+		return -EINVAL;
+	}
+
+	status = nfs4_legacy_state_init(net);
+	if (status)
+		return status;
+
+	status = nfsd4_load_reboot_recovery_data(net);
+	if (status)
+		goto err;
+	printk("NFSD: Using legacy client tracking operations.\n");
+	return 0;
+
+err:
+	nfs4_legacy_state_shutdown(net);
+	return status;
+}
+
+static void
+nfsd4_legacy_tracking_exit(struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	nfs4_release_reclaim(nn);
+	nfsd4_shutdown_recdir(net);
+	nfs4_legacy_state_shutdown(net);
+}
+
+/*
+ * Change the NFSv4 recovery directory to recdir.
+ */
+int
+nfs4_reset_recoverydir(char *recdir)
+{
+	int status;
+	struct path path;
+
+	status = kern_path(recdir, LOOKUP_FOLLOW, &path);
+	if (status)
+		return status;
+	status = -ENOTDIR;
+	if (d_is_dir(path.dentry)) {
+		strcpy(user_recovery_dirname, recdir);
+		status = 0;
+	}
+	path_put(&path);
+	return status;
+}
+
+char *
+nfs4_recoverydir(void)
+{
+	return user_recovery_dirname;
+}
+
+static int
+nfsd4_check_legacy_client(struct nfs4_client *clp)
+{
+	int status;
+	char dname[HEXDIR_LEN];
+	struct nfs4_client_reclaim *crp;
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+	struct xdr_netobj name;
+
+	/* did we already find that this client is stable? */
+	if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
+		return 0;
+
+	status = nfs4_make_rec_clidname(dname, &clp->cl_name);
+	if (status) {
+		legacy_recdir_name_error(clp, status);
+		return status;
+	}
+
+	/* look for it in the reclaim hashtable otherwise */
+	name.data = kmemdup(dname, HEXDIR_LEN, GFP_KERNEL);
+	if (!name.data) {
+		dprintk("%s: failed to allocate memory for name.data!\n",
+			__func__);
+		goto out_enoent;
+	}
+	name.len = HEXDIR_LEN;
+	crp = nfsd4_find_reclaim_client(name, nn);
+	kfree(name.data);
+	if (crp) {
+		set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
+		crp->cr_clp = clp;
+		return 0;
+	}
+
+out_enoent:
+	return -ENOENT;
+}
+
+static const struct nfsd4_client_tracking_ops nfsd4_legacy_tracking_ops = {
+	.init		= nfsd4_legacy_tracking_init,
+	.exit		= nfsd4_legacy_tracking_exit,
+	.create		= nfsd4_create_clid_dir,
+	.remove		= nfsd4_remove_clid_dir,
+	.check		= nfsd4_check_legacy_client,
+	.grace_done	= nfsd4_recdir_purge_old,
+	.version	= 1,
+	.msglen		= 0,
+};
+
+/* Globals */
+#define NFSD_PIPE_DIR		"nfsd"
+#define NFSD_CLD_PIPE		"cld"
+
+/* per-net-ns structure for holding cld upcall info */
+struct cld_net {
+	struct rpc_pipe		*cn_pipe;
+	spinlock_t		 cn_lock;
+	struct list_head	 cn_list;
+	unsigned int		 cn_xid;
+	bool			 cn_has_legacy;
+	struct crypto_shash	*cn_tfm;
+};
+
+struct cld_upcall {
+	struct list_head	 cu_list;
+	struct cld_net		*cu_net;
+	struct completion	 cu_done;
+	union {
+		struct cld_msg_hdr	 cu_hdr;
+		struct cld_msg		 cu_msg;
+		struct cld_msg_v2	 cu_msg_v2;
+	} cu_u;
+};
+
+static int
+__cld_pipe_upcall(struct rpc_pipe *pipe, void *cmsg, struct nfsd_net *nn)
+{
+	int ret;
+	struct rpc_pipe_msg msg;
+	struct cld_upcall *cup = container_of(cmsg, struct cld_upcall, cu_u);
+
+	memset(&msg, 0, sizeof(msg));
+	msg.data = cmsg;
+	msg.len = nn->client_tracking_ops->msglen;
+
+	ret = rpc_queue_upcall(pipe, &msg);
+	if (ret < 0) {
+		goto out;
+	}
+
+	wait_for_completion(&cup->cu_done);
+
+	if (msg.errno < 0)
+		ret = msg.errno;
+out:
+	return ret;
+}
+
+static int
+cld_pipe_upcall(struct rpc_pipe *pipe, void *cmsg, struct nfsd_net *nn)
+{
+	int ret;
+
+	/*
+	 * -EAGAIN occurs when pipe is closed and reopened while there are
+	 *  upcalls queued.
+	 */
+	do {
+		ret = __cld_pipe_upcall(pipe, cmsg, nn);
+	} while (ret == -EAGAIN);
+
+	return ret;
+}
+
+static ssize_t
+__cld_pipe_inprogress_downcall(const struct cld_msg_v2 __user *cmsg,
+		struct nfsd_net *nn)
+{
+	uint8_t cmd, princhashlen;
+	struct xdr_netobj name, princhash = { .len = 0, .data = NULL };
+	uint16_t namelen;
+	struct cld_net *cn = nn->cld_net;
+
+	if (get_user(cmd, &cmsg->cm_cmd)) {
+		dprintk("%s: error when copying cmd from userspace", __func__);
+		return -EFAULT;
+	}
+	if (cmd == Cld_GraceStart) {
+		if (nn->client_tracking_ops->version >= 2) {
+			const struct cld_clntinfo __user *ci;
+
+			ci = &cmsg->cm_u.cm_clntinfo;
+			if (get_user(namelen, &ci->cc_name.cn_len))
+				return -EFAULT;
+			name.data = memdup_user(&ci->cc_name.cn_id, namelen);
+			if (IS_ERR_OR_NULL(name.data))
+				return -EFAULT;
+			name.len = namelen;
+			get_user(princhashlen, &ci->cc_princhash.cp_len);
+			if (princhashlen > 0) {
+				princhash.data = memdup_user(
+						&ci->cc_princhash.cp_data,
+						princhashlen);
+				if (IS_ERR_OR_NULL(princhash.data)) {
+					kfree(name.data);
+					return -EFAULT;
+				}
+				princhash.len = princhashlen;
+			} else
+				princhash.len = 0;
+		} else {
+			const struct cld_name __user *cnm;
+
+			cnm = &cmsg->cm_u.cm_name;
+			if (get_user(namelen, &cnm->cn_len))
+				return -EFAULT;
+			name.data = memdup_user(&cnm->cn_id, namelen);
+			if (IS_ERR_OR_NULL(name.data))
+				return -EFAULT;
+			name.len = namelen;
+		}
+		if (name.len > 5 && memcmp(name.data, "hash:", 5) == 0) {
+			name.len = name.len - 5;
+			memmove(name.data, name.data + 5, name.len);
+			cn->cn_has_legacy = true;
+		}
+		if (!nfs4_client_to_reclaim(name, princhash, nn)) {
+			kfree(name.data);
+			kfree(princhash.data);
+			return -EFAULT;
+		}
+		return nn->client_tracking_ops->msglen;
+	}
+	return -EFAULT;
+}
+
+static ssize_t
+cld_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
+{
+	struct cld_upcall *tmp, *cup;
+	struct cld_msg_hdr __user *hdr = (struct cld_msg_hdr __user *)src;
+	struct cld_msg_v2 __user *cmsg = (struct cld_msg_v2 __user *)src;
+	uint32_t xid;
+	struct nfsd_net *nn = net_generic(file_inode(filp)->i_sb->s_fs_info,
+						nfsd_net_id);
+	struct cld_net *cn = nn->cld_net;
+	int16_t status;
+
+	if (mlen != nn->client_tracking_ops->msglen) {
+		dprintk("%s: got %zu bytes, expected %zu\n", __func__, mlen,
+			nn->client_tracking_ops->msglen);
+		return -EINVAL;
+	}
+
+	/* copy just the xid so we can try to find that */
+	if (copy_from_user(&xid, &hdr->cm_xid, sizeof(xid)) != 0) {
+		dprintk("%s: error when copying xid from userspace", __func__);
+		return -EFAULT;
+	}
+
+	/*
+	 * copy the status so we know whether to remove the upcall from the
+	 * list (for -EINPROGRESS, we just want to make sure the xid is
+	 * valid, not remove the upcall from the list)
+	 */
+	if (get_user(status, &hdr->cm_status)) {
+		dprintk("%s: error when copying status from userspace", __func__);
+		return -EFAULT;
+	}
+
+	/* walk the list and find corresponding xid */
+	cup = NULL;
+	spin_lock(&cn->cn_lock);
+	list_for_each_entry(tmp, &cn->cn_list, cu_list) {
+		if (get_unaligned(&tmp->cu_u.cu_hdr.cm_xid) == xid) {
+			cup = tmp;
+			if (status != -EINPROGRESS)
+				list_del_init(&cup->cu_list);
+			break;
+		}
+	}
+	spin_unlock(&cn->cn_lock);
+
+	/* couldn't find upcall? */
+	if (!cup) {
+		dprintk("%s: couldn't find upcall -- xid=%u\n", __func__, xid);
+		return -EINVAL;
+	}
+
+	if (status == -EINPROGRESS)
+		return __cld_pipe_inprogress_downcall(cmsg, nn);
+
+	if (copy_from_user(&cup->cu_u.cu_msg_v2, src, mlen) != 0)
+		return -EFAULT;
+
+	complete(&cup->cu_done);
+	return mlen;
+}
+
+static void
+cld_pipe_destroy_msg(struct rpc_pipe_msg *msg)
+{
+	struct cld_msg *cmsg = msg->data;
+	struct cld_upcall *cup = container_of(cmsg, struct cld_upcall,
+						 cu_u.cu_msg);
+
+	/* errno >= 0 means we got a downcall */
+	if (msg->errno >= 0)
+		return;
+
+	complete(&cup->cu_done);
+}
+
+static const struct rpc_pipe_ops cld_upcall_ops = {
+	.upcall		= rpc_pipe_generic_upcall,
+	.downcall	= cld_pipe_downcall,
+	.destroy_msg	= cld_pipe_destroy_msg,
+};
+
+static struct dentry *
+nfsd4_cld_register_sb(struct super_block *sb, struct rpc_pipe *pipe)
+{
+	struct dentry *dir, *dentry;
+
+	dir = rpc_d_lookup_sb(sb, NFSD_PIPE_DIR);
+	if (dir == NULL)
+		return ERR_PTR(-ENOENT);
+	dentry = rpc_mkpipe_dentry(dir, NFSD_CLD_PIPE, NULL, pipe);
+	dput(dir);
+	return dentry;
+}
+
+static void
+nfsd4_cld_unregister_sb(struct rpc_pipe *pipe)
+{
+	if (pipe->dentry)
+		rpc_unlink(pipe->dentry);
+}
+
+static struct dentry *
+nfsd4_cld_register_net(struct net *net, struct rpc_pipe *pipe)
+{
+	struct super_block *sb;
+	struct dentry *dentry;
+
+	sb = rpc_get_sb_net(net);
+	if (!sb)
+		return NULL;
+	dentry = nfsd4_cld_register_sb(sb, pipe);
+	rpc_put_sb_net(net);
+	return dentry;
+}
+
+static void
+nfsd4_cld_unregister_net(struct net *net, struct rpc_pipe *pipe)
+{
+	struct super_block *sb;
+
+	sb = rpc_get_sb_net(net);
+	if (sb) {
+		nfsd4_cld_unregister_sb(pipe);
+		rpc_put_sb_net(net);
+	}
+}
+
+/* Initialize rpc_pipefs pipe for communication with client tracking daemon */
+static int
+__nfsd4_init_cld_pipe(struct net *net)
+{
+	int ret;
+	struct dentry *dentry;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	struct cld_net *cn;
+
+	if (nn->cld_net)
+		return 0;
+
+	cn = kzalloc(sizeof(*cn), GFP_KERNEL);
+	if (!cn) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	cn->cn_pipe = rpc_mkpipe_data(&cld_upcall_ops, RPC_PIPE_WAIT_FOR_OPEN);
+	if (IS_ERR(cn->cn_pipe)) {
+		ret = PTR_ERR(cn->cn_pipe);
+		goto err;
+	}
+	spin_lock_init(&cn->cn_lock);
+	INIT_LIST_HEAD(&cn->cn_list);
+
+	dentry = nfsd4_cld_register_net(net, cn->cn_pipe);
+	if (IS_ERR(dentry)) {
+		ret = PTR_ERR(dentry);
+		goto err_destroy_data;
+	}
+
+	cn->cn_pipe->dentry = dentry;
+	cn->cn_has_legacy = false;
+	nn->cld_net = cn;
+	return 0;
+
+err_destroy_data:
+	rpc_destroy_pipe_data(cn->cn_pipe);
+err:
+	kfree(cn);
+	printk(KERN_ERR "NFSD: unable to create nfsdcld upcall pipe (%d)\n",
+			ret);
+	return ret;
+}
+
+static int
+nfsd4_init_cld_pipe(struct net *net)
+{
+	int status;
+
+	status = __nfsd4_init_cld_pipe(net);
+	if (!status)
+		printk("NFSD: Using old nfsdcld client tracking operations.\n");
+	return status;
+}
+
+static void
+nfsd4_remove_cld_pipe(struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	struct cld_net *cn = nn->cld_net;
+
+	nfsd4_cld_unregister_net(net, cn->cn_pipe);
+	rpc_destroy_pipe_data(cn->cn_pipe);
+	if (cn->cn_tfm)
+		crypto_free_shash(cn->cn_tfm);
+	kfree(nn->cld_net);
+	nn->cld_net = NULL;
+}
+
+static struct cld_upcall *
+alloc_cld_upcall(struct nfsd_net *nn)
+{
+	struct cld_upcall *new, *tmp;
+	struct cld_net *cn = nn->cld_net;
+
+	new = kzalloc(sizeof(*new), GFP_KERNEL);
+	if (!new)
+		return new;
+
+	/* FIXME: hard cap on number in flight? */
+restart_search:
+	spin_lock(&cn->cn_lock);
+	list_for_each_entry(tmp, &cn->cn_list, cu_list) {
+		if (tmp->cu_u.cu_msg.cm_xid == cn->cn_xid) {
+			cn->cn_xid++;
+			spin_unlock(&cn->cn_lock);
+			goto restart_search;
+		}
+	}
+	init_completion(&new->cu_done);
+	new->cu_u.cu_msg.cm_vers = nn->client_tracking_ops->version;
+	put_unaligned(cn->cn_xid++, &new->cu_u.cu_msg.cm_xid);
+	new->cu_net = cn;
+	list_add(&new->cu_list, &cn->cn_list);
+	spin_unlock(&cn->cn_lock);
+
+	dprintk("%s: allocated xid %u\n", __func__, new->cu_u.cu_msg.cm_xid);
+
+	return new;
+}
+
+static void
+free_cld_upcall(struct cld_upcall *victim)
+{
+	struct cld_net *cn = victim->cu_net;
+
+	spin_lock(&cn->cn_lock);
+	list_del(&victim->cu_list);
+	spin_unlock(&cn->cn_lock);
+	kfree(victim);
+}
+
+/* Ask daemon to create a new record */
+static void
+nfsd4_cld_create(struct nfs4_client *clp)
+{
+	int ret;
+	struct cld_upcall *cup;
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+	struct cld_net *cn = nn->cld_net;
+
+	/* Don't upcall if it's already stored */
+	if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
+		return;
+
+	cup = alloc_cld_upcall(nn);
+	if (!cup) {
+		ret = -ENOMEM;
+		goto out_err;
+	}
+
+	cup->cu_u.cu_msg.cm_cmd = Cld_Create;
+	cup->cu_u.cu_msg.cm_u.cm_name.cn_len = clp->cl_name.len;
+	memcpy(cup->cu_u.cu_msg.cm_u.cm_name.cn_id, clp->cl_name.data,
+			clp->cl_name.len);
+
+	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg, nn);
+	if (!ret) {
+		ret = cup->cu_u.cu_msg.cm_status;
+		set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
+	}
+
+	free_cld_upcall(cup);
+out_err:
+	if (ret)
+		printk(KERN_ERR "NFSD: Unable to create client "
+				"record on stable storage: %d\n", ret);
+}
+
+/* Ask daemon to create a new record */
+static void
+nfsd4_cld_create_v2(struct nfs4_client *clp)
+{
+	int ret;
+	struct cld_upcall *cup;
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+	struct cld_net *cn = nn->cld_net;
+	struct cld_msg_v2 *cmsg;
+	struct crypto_shash *tfm = cn->cn_tfm;
+	struct xdr_netobj cksum;
+	char *principal = NULL;
+
+	/* Don't upcall if it's already stored */
+	if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
+		return;
+
+	cup = alloc_cld_upcall(nn);
+	if (!cup) {
+		ret = -ENOMEM;
+		goto out_err;
+	}
+
+	cmsg = &cup->cu_u.cu_msg_v2;
+	cmsg->cm_cmd = Cld_Create;
+	cmsg->cm_u.cm_clntinfo.cc_name.cn_len = clp->cl_name.len;
+	memcpy(cmsg->cm_u.cm_clntinfo.cc_name.cn_id, clp->cl_name.data,
+			clp->cl_name.len);
+	if (clp->cl_cred.cr_raw_principal)
+		principal = clp->cl_cred.cr_raw_principal;
+	else if (clp->cl_cred.cr_principal)
+		principal = clp->cl_cred.cr_principal;
+	if (principal) {
+		cksum.len = crypto_shash_digestsize(tfm);
+		cksum.data = kmalloc(cksum.len, GFP_KERNEL);
+		if (cksum.data == NULL) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		ret = crypto_shash_tfm_digest(tfm, principal, strlen(principal),
+					      cksum.data);
+		if (ret) {
+			kfree(cksum.data);
+			goto out;
+		}
+		cmsg->cm_u.cm_clntinfo.cc_princhash.cp_len = cksum.len;
+		memcpy(cmsg->cm_u.cm_clntinfo.cc_princhash.cp_data,
+		       cksum.data, cksum.len);
+		kfree(cksum.data);
+	} else
+		cmsg->cm_u.cm_clntinfo.cc_princhash.cp_len = 0;
+
+	ret = cld_pipe_upcall(cn->cn_pipe, cmsg, nn);
+	if (!ret) {
+		ret = cmsg->cm_status;
+		set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
+	}
+
+out:
+	free_cld_upcall(cup);
+out_err:
+	if (ret)
+		pr_err("NFSD: Unable to create client record on stable storage: %d\n",
+				ret);
+}
+
+/* Ask daemon to create a new record */
+static void
+nfsd4_cld_remove(struct nfs4_client *clp)
+{
+	int ret;
+	struct cld_upcall *cup;
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+	struct cld_net *cn = nn->cld_net;
+
+	/* Don't upcall if it's already removed */
+	if (!test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
+		return;
+
+	cup = alloc_cld_upcall(nn);
+	if (!cup) {
+		ret = -ENOMEM;
+		goto out_err;
+	}
+
+	cup->cu_u.cu_msg.cm_cmd = Cld_Remove;
+	cup->cu_u.cu_msg.cm_u.cm_name.cn_len = clp->cl_name.len;
+	memcpy(cup->cu_u.cu_msg.cm_u.cm_name.cn_id, clp->cl_name.data,
+			clp->cl_name.len);
+
+	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg, nn);
+	if (!ret) {
+		ret = cup->cu_u.cu_msg.cm_status;
+		clear_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
+	}
+
+	free_cld_upcall(cup);
+out_err:
+	if (ret)
+		printk(KERN_ERR "NFSD: Unable to remove client "
+				"record from stable storage: %d\n", ret);
+}
+
+/*
+ * For older nfsdcld's that do not allow us to "slurp" the clients
+ * from the tracking database during startup.
+ *
+ * Check for presence of a record, and update its timestamp
+ */
+static int
+nfsd4_cld_check_v0(struct nfs4_client *clp)
+{
+	int ret;
+	struct cld_upcall *cup;
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+	struct cld_net *cn = nn->cld_net;
+
+	/* Don't upcall if one was already stored during this grace pd */
+	if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
+		return 0;
+
+	cup = alloc_cld_upcall(nn);
+	if (!cup) {
+		printk(KERN_ERR "NFSD: Unable to check client record on "
+				"stable storage: %d\n", -ENOMEM);
+		return -ENOMEM;
+	}
+
+	cup->cu_u.cu_msg.cm_cmd = Cld_Check;
+	cup->cu_u.cu_msg.cm_u.cm_name.cn_len = clp->cl_name.len;
+	memcpy(cup->cu_u.cu_msg.cm_u.cm_name.cn_id, clp->cl_name.data,
+			clp->cl_name.len);
+
+	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg, nn);
+	if (!ret) {
+		ret = cup->cu_u.cu_msg.cm_status;
+		set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
+	}
+
+	free_cld_upcall(cup);
+	return ret;
+}
+
+/*
+ * For newer nfsdcld's that allow us to "slurp" the clients
+ * from the tracking database during startup.
+ *
+ * Check for presence of a record in the reclaim_str_hashtbl
+ */
+static int
+nfsd4_cld_check(struct nfs4_client *clp)
+{
+	struct nfs4_client_reclaim *crp;
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+	struct cld_net *cn = nn->cld_net;
+	int status;
+	char dname[HEXDIR_LEN];
+	struct xdr_netobj name;
+
+	/* did we already find that this client is stable? */
+	if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
+		return 0;
+
+	/* look for it in the reclaim hashtable otherwise */
+	crp = nfsd4_find_reclaim_client(clp->cl_name, nn);
+	if (crp)
+		goto found;
+
+	if (cn->cn_has_legacy) {
+		status = nfs4_make_rec_clidname(dname, &clp->cl_name);
+		if (status)
+			return -ENOENT;
+
+		name.data = kmemdup(dname, HEXDIR_LEN, GFP_KERNEL);
+		if (!name.data) {
+			dprintk("%s: failed to allocate memory for name.data!\n",
+				__func__);
+			return -ENOENT;
+		}
+		name.len = HEXDIR_LEN;
+		crp = nfsd4_find_reclaim_client(name, nn);
+		kfree(name.data);
+		if (crp)
+			goto found;
+
+	}
+	return -ENOENT;
+found:
+	crp->cr_clp = clp;
+	return 0;
+}
+
+static int
+nfsd4_cld_check_v2(struct nfs4_client *clp)
+{
+	struct nfs4_client_reclaim *crp;
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+	struct cld_net *cn = nn->cld_net;
+	int status;
+	char dname[HEXDIR_LEN];
+	struct xdr_netobj name;
+	struct crypto_shash *tfm = cn->cn_tfm;
+	struct xdr_netobj cksum;
+	char *principal = NULL;
+
+	/* did we already find that this client is stable? */
+	if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
+		return 0;
+
+	/* look for it in the reclaim hashtable otherwise */
+	crp = nfsd4_find_reclaim_client(clp->cl_name, nn);
+	if (crp)
+		goto found;
+
+	if (cn->cn_has_legacy) {
+		status = nfs4_make_rec_clidname(dname, &clp->cl_name);
+		if (status)
+			return -ENOENT;
+
+		name.data = kmemdup(dname, HEXDIR_LEN, GFP_KERNEL);
+		if (!name.data) {
+			dprintk("%s: failed to allocate memory for name.data\n",
+					__func__);
+			return -ENOENT;
+		}
+		name.len = HEXDIR_LEN;
+		crp = nfsd4_find_reclaim_client(name, nn);
+		kfree(name.data);
+		if (crp)
+			goto found;
+
+	}
+	return -ENOENT;
+found:
+	if (crp->cr_princhash.len) {
+		if (clp->cl_cred.cr_raw_principal)
+			principal = clp->cl_cred.cr_raw_principal;
+		else if (clp->cl_cred.cr_principal)
+			principal = clp->cl_cred.cr_principal;
+		if (principal == NULL)
+			return -ENOENT;
+		cksum.len = crypto_shash_digestsize(tfm);
+		cksum.data = kmalloc(cksum.len, GFP_KERNEL);
+		if (cksum.data == NULL)
+			return -ENOENT;
+		status = crypto_shash_tfm_digest(tfm, principal,
+						 strlen(principal), cksum.data);
+		if (status) {
+			kfree(cksum.data);
+			return -ENOENT;
+		}
+		if (memcmp(crp->cr_princhash.data, cksum.data,
+				crp->cr_princhash.len)) {
+			kfree(cksum.data);
+			return -ENOENT;
+		}
+		kfree(cksum.data);
+	}
+	crp->cr_clp = clp;
+	return 0;
+}
+
+static int
+nfsd4_cld_grace_start(struct nfsd_net *nn)
+{
+	int ret;
+	struct cld_upcall *cup;
+	struct cld_net *cn = nn->cld_net;
+
+	cup = alloc_cld_upcall(nn);
+	if (!cup) {
+		ret = -ENOMEM;
+		goto out_err;
+	}
+
+	cup->cu_u.cu_msg.cm_cmd = Cld_GraceStart;
+	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg, nn);
+	if (!ret)
+		ret = cup->cu_u.cu_msg.cm_status;
+
+	free_cld_upcall(cup);
+out_err:
+	if (ret)
+		dprintk("%s: Unable to get clients from userspace: %d\n",
+			__func__, ret);
+	return ret;
+}
+
+/* For older nfsdcld's that need cm_gracetime */
+static void
+nfsd4_cld_grace_done_v0(struct nfsd_net *nn)
+{
+	int ret;
+	struct cld_upcall *cup;
+	struct cld_net *cn = nn->cld_net;
+
+	cup = alloc_cld_upcall(nn);
+	if (!cup) {
+		ret = -ENOMEM;
+		goto out_err;
+	}
+
+	cup->cu_u.cu_msg.cm_cmd = Cld_GraceDone;
+	cup->cu_u.cu_msg.cm_u.cm_gracetime = nn->boot_time;
+	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg, nn);
+	if (!ret)
+		ret = cup->cu_u.cu_msg.cm_status;
+
+	free_cld_upcall(cup);
+out_err:
+	if (ret)
+		printk(KERN_ERR "NFSD: Unable to end grace period: %d\n", ret);
+}
+
+/*
+ * For newer nfsdcld's that do not need cm_gracetime.  We also need to call
+ * nfs4_release_reclaim() to clear out the reclaim_str_hashtbl.
+ */
+static void
+nfsd4_cld_grace_done(struct nfsd_net *nn)
+{
+	int ret;
+	struct cld_upcall *cup;
+	struct cld_net *cn = nn->cld_net;
+
+	cup = alloc_cld_upcall(nn);
+	if (!cup) {
+		ret = -ENOMEM;
+		goto out_err;
+	}
+
+	cup->cu_u.cu_msg.cm_cmd = Cld_GraceDone;
+	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg, nn);
+	if (!ret)
+		ret = cup->cu_u.cu_msg.cm_status;
+
+	free_cld_upcall(cup);
+out_err:
+	nfs4_release_reclaim(nn);
+	if (ret)
+		printk(KERN_ERR "NFSD: Unable to end grace period: %d\n", ret);
+}
+
+static int
+nfs4_cld_state_init(struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	int i;
+
+	nn->reclaim_str_hashtbl = kmalloc_array(CLIENT_HASH_SIZE,
+						sizeof(struct list_head),
+						GFP_KERNEL);
+	if (!nn->reclaim_str_hashtbl)
+		return -ENOMEM;
+
+	for (i = 0; i < CLIENT_HASH_SIZE; i++)
+		INIT_LIST_HEAD(&nn->reclaim_str_hashtbl[i]);
+	nn->reclaim_str_hashtbl_size = 0;
+	nn->track_reclaim_completes = true;
+	atomic_set(&nn->nr_reclaim_complete, 0);
+
+	return 0;
+}
+
+static void
+nfs4_cld_state_shutdown(struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	nn->track_reclaim_completes = false;
+	kfree(nn->reclaim_str_hashtbl);
+}
+
+static bool
+cld_running(struct nfsd_net *nn)
+{
+	struct cld_net *cn = nn->cld_net;
+	struct rpc_pipe *pipe = cn->cn_pipe;
+
+	return pipe->nreaders || pipe->nwriters;
+}
+
+static int
+nfsd4_cld_get_version(struct nfsd_net *nn)
+{
+	int ret = 0;
+	struct cld_upcall *cup;
+	struct cld_net *cn = nn->cld_net;
+	uint8_t version;
+
+	cup = alloc_cld_upcall(nn);
+	if (!cup) {
+		ret = -ENOMEM;
+		goto out_err;
+	}
+	cup->cu_u.cu_msg.cm_cmd = Cld_GetVersion;
+	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg, nn);
+	if (!ret) {
+		ret = cup->cu_u.cu_msg.cm_status;
+		if (ret)
+			goto out_free;
+		version = cup->cu_u.cu_msg.cm_u.cm_version;
+		dprintk("%s: userspace returned version %u\n",
+				__func__, version);
+		if (version < 1)
+			version = 1;
+		else if (version > CLD_UPCALL_VERSION)
+			version = CLD_UPCALL_VERSION;
+
+		switch (version) {
+		case 1:
+			nn->client_tracking_ops = &nfsd4_cld_tracking_ops;
+			break;
+		case 2:
+			nn->client_tracking_ops = &nfsd4_cld_tracking_ops_v2;
+			break;
+		default:
+			break;
+		}
+	}
+out_free:
+	free_cld_upcall(cup);
+out_err:
+	if (ret)
+		dprintk("%s: Unable to get version from userspace: %d\n",
+			__func__, ret);
+	return ret;
+}
+
+static int
+nfsd4_cld_tracking_init(struct net *net)
+{
+	int status;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	bool running;
+	int retries = 10;
+	struct crypto_shash *tfm;
+
+	status = nfs4_cld_state_init(net);
+	if (status)
+		return status;
+
+	status = __nfsd4_init_cld_pipe(net);
+	if (status)
+		goto err_shutdown;
+
+	/*
+	 * rpc pipe upcalls take 30 seconds to time out, so we don't want to
+	 * queue an upcall unless we know that nfsdcld is running (because we
+	 * want this to fail fast so that nfsd4_client_tracking_init() can try
+	 * the next client tracking method).  nfsdcld should already be running
+	 * before nfsd is started, so the wait here is for nfsdcld to open the
+	 * pipefs file we just created.
+	 */
+	while (!(running = cld_running(nn)) && retries--)
+		msleep(100);
+
+	if (!running) {
+		status = -ETIMEDOUT;
+		goto err_remove;
+	}
+	tfm = crypto_alloc_shash("sha256", 0, 0);
+	if (IS_ERR(tfm)) {
+		status = PTR_ERR(tfm);
+		goto err_remove;
+	}
+	nn->cld_net->cn_tfm = tfm;
+
+	status = nfsd4_cld_get_version(nn);
+	if (status == -EOPNOTSUPP)
+		pr_warn("NFSD: nfsdcld GetVersion upcall failed. Please upgrade nfsdcld.\n");
+
+	status = nfsd4_cld_grace_start(nn);
+	if (status) {
+		if (status == -EOPNOTSUPP)
+			pr_warn("NFSD: nfsdcld GraceStart upcall failed. Please upgrade nfsdcld.\n");
+		nfs4_release_reclaim(nn);
+		goto err_remove;
+	} else
+		printk("NFSD: Using nfsdcld client tracking operations.\n");
+	return 0;
+
+err_remove:
+	nfsd4_remove_cld_pipe(net);
+err_shutdown:
+	nfs4_cld_state_shutdown(net);
+	return status;
+}
+
+static void
+nfsd4_cld_tracking_exit(struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	nfs4_release_reclaim(nn);
+	nfsd4_remove_cld_pipe(net);
+	nfs4_cld_state_shutdown(net);
+}
+
+/* For older nfsdcld's */
+static const struct nfsd4_client_tracking_ops nfsd4_cld_tracking_ops_v0 = {
+	.init		= nfsd4_init_cld_pipe,
+	.exit		= nfsd4_remove_cld_pipe,
+	.create		= nfsd4_cld_create,
+	.remove		= nfsd4_cld_remove,
+	.check		= nfsd4_cld_check_v0,
+	.grace_done	= nfsd4_cld_grace_done_v0,
+	.version	= 1,
+	.msglen		= sizeof(struct cld_msg),
+};
+
+/* For newer nfsdcld's */
+static const struct nfsd4_client_tracking_ops nfsd4_cld_tracking_ops = {
+	.init		= nfsd4_cld_tracking_init,
+	.exit		= nfsd4_cld_tracking_exit,
+	.create		= nfsd4_cld_create,
+	.remove		= nfsd4_cld_remove,
+	.check		= nfsd4_cld_check,
+	.grace_done	= nfsd4_cld_grace_done,
+	.version	= 1,
+	.msglen		= sizeof(struct cld_msg),
+};
+
+/* v2 create/check ops include the principal, if available */
+static const struct nfsd4_client_tracking_ops nfsd4_cld_tracking_ops_v2 = {
+	.init		= nfsd4_cld_tracking_init,
+	.exit		= nfsd4_cld_tracking_exit,
+	.create		= nfsd4_cld_create_v2,
+	.remove		= nfsd4_cld_remove,
+	.check		= nfsd4_cld_check_v2,
+	.grace_done	= nfsd4_cld_grace_done,
+	.version	= 2,
+	.msglen		= sizeof(struct cld_msg_v2),
+};
+
+/* upcall via usermodehelper */
+static char cltrack_prog[PATH_MAX] = "/sbin/nfsdcltrack";
+module_param_string(cltrack_prog, cltrack_prog, sizeof(cltrack_prog),
+			S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(cltrack_prog, "Path to the nfsdcltrack upcall program");
+
+static bool cltrack_legacy_disable;
+module_param(cltrack_legacy_disable, bool, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(cltrack_legacy_disable,
+		"Disable legacy recoverydir conversion. Default: false");
+
+#define LEGACY_TOPDIR_ENV_PREFIX "NFSDCLTRACK_LEGACY_TOPDIR="
+#define LEGACY_RECDIR_ENV_PREFIX "NFSDCLTRACK_LEGACY_RECDIR="
+#define HAS_SESSION_ENV_PREFIX "NFSDCLTRACK_CLIENT_HAS_SESSION="
+#define GRACE_START_ENV_PREFIX "NFSDCLTRACK_GRACE_START="
+
+static char *
+nfsd4_cltrack_legacy_topdir(void)
+{
+	int copied;
+	size_t len;
+	char *result;
+
+	if (cltrack_legacy_disable)
+		return NULL;
+
+	len = strlen(LEGACY_TOPDIR_ENV_PREFIX) +
+		strlen(nfs4_recoverydir()) + 1;
+
+	result = kmalloc(len, GFP_KERNEL);
+	if (!result)
+		return result;
+
+	copied = snprintf(result, len, LEGACY_TOPDIR_ENV_PREFIX "%s",
+				nfs4_recoverydir());
+	if (copied >= len) {
+		/* just return nothing if output was truncated */
+		kfree(result);
+		return NULL;
+	}
+
+	return result;
+}
+
+static char *
+nfsd4_cltrack_legacy_recdir(const struct xdr_netobj *name)
+{
+	int copied;
+	size_t len;
+	char *result;
+
+	if (cltrack_legacy_disable)
+		return NULL;
+
+	/* +1 is for '/' between "topdir" and "recdir" */
+	len = strlen(LEGACY_RECDIR_ENV_PREFIX) +
+		strlen(nfs4_recoverydir()) + 1 + HEXDIR_LEN;
+
+	result = kmalloc(len, GFP_KERNEL);
+	if (!result)
+		return result;
+
+	copied = snprintf(result, len, LEGACY_RECDIR_ENV_PREFIX "%s/",
+				nfs4_recoverydir());
+	if (copied > (len - HEXDIR_LEN)) {
+		/* just return nothing if output will be truncated */
+		kfree(result);
+		return NULL;
+	}
+
+	copied = nfs4_make_rec_clidname(result + copied, name);
+	if (copied) {
+		kfree(result);
+		return NULL;
+	}
+
+	return result;
+}
+
+static char *
+nfsd4_cltrack_client_has_session(struct nfs4_client *clp)
+{
+	int copied;
+	size_t len;
+	char *result;
+
+	/* prefix + Y/N character + terminating NULL */
+	len = strlen(HAS_SESSION_ENV_PREFIX) + 1 + 1;
+
+	result = kmalloc(len, GFP_KERNEL);
+	if (!result)
+		return result;
+
+	copied = snprintf(result, len, HAS_SESSION_ENV_PREFIX "%c",
+				clp->cl_minorversion ? 'Y' : 'N');
+	if (copied >= len) {
+		/* just return nothing if output was truncated */
+		kfree(result);
+		return NULL;
+	}
+
+	return result;
+}
+
+static char *
+nfsd4_cltrack_grace_start(time64_t grace_start)
+{
+	int copied;
+	size_t len;
+	char *result;
+
+	/* prefix + max width of int64_t string + terminating NULL */
+	len = strlen(GRACE_START_ENV_PREFIX) + 22 + 1;
+
+	result = kmalloc(len, GFP_KERNEL);
+	if (!result)
+		return result;
+
+	copied = snprintf(result, len, GRACE_START_ENV_PREFIX "%lld",
+				grace_start);
+	if (copied >= len) {
+		/* just return nothing if output was truncated */
+		kfree(result);
+		return NULL;
+	}
+
+	return result;
+}
+
+static int
+nfsd4_umh_cltrack_upcall(char *cmd, char *arg, char *env0, char *env1)
+{
+	char *envp[3];
+	char *argv[4];
+	int ret;
+
+	if (unlikely(!cltrack_prog[0])) {
+		dprintk("%s: cltrack_prog is disabled\n", __func__);
+		return -EACCES;
+	}
+
+	dprintk("%s: cmd: %s\n", __func__, cmd);
+	dprintk("%s: arg: %s\n", __func__, arg ? arg : "(null)");
+	dprintk("%s: env0: %s\n", __func__, env0 ? env0 : "(null)");
+	dprintk("%s: env1: %s\n", __func__, env1 ? env1 : "(null)");
+
+	envp[0] = env0;
+	envp[1] = env1;
+	envp[2] = NULL;
+
+	argv[0] = (char *)cltrack_prog;
+	argv[1] = cmd;
+	argv[2] = arg;
+	argv[3] = NULL;
+
+	ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
+	/*
+	 * Disable the upcall mechanism if we're getting an ENOENT or EACCES
+	 * error. The admin can re-enable it on the fly by using sysfs
+	 * once the problem has been fixed.
+	 */
+	if (ret == -ENOENT || ret == -EACCES) {
+		dprintk("NFSD: %s was not found or isn't executable (%d). "
+			"Setting cltrack_prog to blank string!",
+			cltrack_prog, ret);
+		cltrack_prog[0] = '\0';
+	}
+	dprintk("%s: %s return value: %d\n", __func__, cltrack_prog, ret);
+
+	return ret;
+}
+
+static char *
+bin_to_hex_dup(const unsigned char *src, int srclen)
+{
+	char *buf;
+
+	/* +1 for terminating NULL */
+	buf = kzalloc((srclen * 2) + 1, GFP_KERNEL);
+	if (!buf)
+		return buf;
+
+	bin2hex(buf, src, srclen);
+	return buf;
+}
+
+static int
+nfsd4_umh_cltrack_init(struct net *net)
+{
+	int ret;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	char *grace_start = nfsd4_cltrack_grace_start(nn->boot_time);
+
+	/* XXX: The usermode helper s not working in container yet. */
+	if (net != &init_net) {
+		pr_warn("NFSD: attempt to initialize umh client tracking in a container ignored.\n");
+		kfree(grace_start);
+		return -EINVAL;
+	}
+
+	ret = nfsd4_umh_cltrack_upcall("init", NULL, grace_start, NULL);
+	kfree(grace_start);
+	if (!ret)
+		printk("NFSD: Using UMH upcall client tracking operations.\n");
+	return ret;
+}
+
+static void
+nfsd4_cltrack_upcall_lock(struct nfs4_client *clp)
+{
+	wait_on_bit_lock(&clp->cl_flags, NFSD4_CLIENT_UPCALL_LOCK,
+			 TASK_UNINTERRUPTIBLE);
+}
+
+static void
+nfsd4_cltrack_upcall_unlock(struct nfs4_client *clp)
+{
+	smp_mb__before_atomic();
+	clear_bit(NFSD4_CLIENT_UPCALL_LOCK, &clp->cl_flags);
+	smp_mb__after_atomic();
+	wake_up_bit(&clp->cl_flags, NFSD4_CLIENT_UPCALL_LOCK);
+}
+
+static void
+nfsd4_umh_cltrack_create(struct nfs4_client *clp)
+{
+	char *hexid, *has_session, *grace_start;
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+
+	/*
+	 * With v4.0 clients, there's little difference in outcome between a
+	 * create and check operation, and we can end up calling into this
+	 * function multiple times per client (once for each openowner). So,
+	 * for v4.0 clients skip upcalling once the client has been recorded
+	 * on stable storage.
+	 *
+	 * For v4.1+ clients, the outcome of the two operations is different,
+	 * so we must ensure that we upcall for the create operation. v4.1+
+	 * clients call this on RECLAIM_COMPLETE though, so we should only end
+	 * up doing a single create upcall per client.
+	 */
+	if (clp->cl_minorversion == 0 &&
+	    test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
+		return;
+
+	hexid = bin_to_hex_dup(clp->cl_name.data, clp->cl_name.len);
+	if (!hexid) {
+		dprintk("%s: can't allocate memory for upcall!\n", __func__);
+		return;
+	}
+
+	has_session = nfsd4_cltrack_client_has_session(clp);
+	grace_start = nfsd4_cltrack_grace_start(nn->boot_time);
+
+	nfsd4_cltrack_upcall_lock(clp);
+	if (!nfsd4_umh_cltrack_upcall("create", hexid, has_session, grace_start))
+		set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
+	nfsd4_cltrack_upcall_unlock(clp);
+
+	kfree(has_session);
+	kfree(grace_start);
+	kfree(hexid);
+}
+
+static void
+nfsd4_umh_cltrack_remove(struct nfs4_client *clp)
+{
+	char *hexid;
+
+	if (!test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
+		return;
+
+	hexid = bin_to_hex_dup(clp->cl_name.data, clp->cl_name.len);
+	if (!hexid) {
+		dprintk("%s: can't allocate memory for upcall!\n", __func__);
+		return;
+	}
+
+	nfsd4_cltrack_upcall_lock(clp);
+	if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags) &&
+	    nfsd4_umh_cltrack_upcall("remove", hexid, NULL, NULL) == 0)
+		clear_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
+	nfsd4_cltrack_upcall_unlock(clp);
+
+	kfree(hexid);
+}
+
+static int
+nfsd4_umh_cltrack_check(struct nfs4_client *clp)
+{
+	int ret;
+	char *hexid, *has_session, *legacy;
+
+	if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
+		return 0;
+
+	hexid = bin_to_hex_dup(clp->cl_name.data, clp->cl_name.len);
+	if (!hexid) {
+		dprintk("%s: can't allocate memory for upcall!\n", __func__);
+		return -ENOMEM;
+	}
+
+	has_session = nfsd4_cltrack_client_has_session(clp);
+	legacy = nfsd4_cltrack_legacy_recdir(&clp->cl_name);
+
+	nfsd4_cltrack_upcall_lock(clp);
+	if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags)) {
+		ret = 0;
+	} else {
+		ret = nfsd4_umh_cltrack_upcall("check", hexid, has_session, legacy);
+		if (ret == 0)
+			set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
+	}
+	nfsd4_cltrack_upcall_unlock(clp);
+	kfree(has_session);
+	kfree(legacy);
+	kfree(hexid);
+
+	return ret;
+}
+
+static void
+nfsd4_umh_cltrack_grace_done(struct nfsd_net *nn)
+{
+	char *legacy;
+	char timestr[22]; /* FIXME: better way to determine max size? */
+
+	sprintf(timestr, "%lld", nn->boot_time);
+	legacy = nfsd4_cltrack_legacy_topdir();
+	nfsd4_umh_cltrack_upcall("gracedone", timestr, legacy, NULL);
+	kfree(legacy);
+}
+
+static const struct nfsd4_client_tracking_ops nfsd4_umh_tracking_ops = {
+	.init		= nfsd4_umh_cltrack_init,
+	.exit		= NULL,
+	.create		= nfsd4_umh_cltrack_create,
+	.remove		= nfsd4_umh_cltrack_remove,
+	.check		= nfsd4_umh_cltrack_check,
+	.grace_done	= nfsd4_umh_cltrack_grace_done,
+	.version	= 1,
+	.msglen		= 0,
+};
+
+int
+nfsd4_client_tracking_init(struct net *net)
+{
+	int status;
+	struct path path;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	/* just run the init if it the method is already decided */
+	if (nn->client_tracking_ops)
+		goto do_init;
+
+	/* First, try to use nfsdcld */
+	nn->client_tracking_ops = &nfsd4_cld_tracking_ops;
+	status = nn->client_tracking_ops->init(net);
+	if (!status)
+		return status;
+	if (status != -ETIMEDOUT) {
+		nn->client_tracking_ops = &nfsd4_cld_tracking_ops_v0;
+		status = nn->client_tracking_ops->init(net);
+		if (!status)
+			return status;
+	}
+
+	/*
+	 * Next, try the UMH upcall.
+	 */
+	nn->client_tracking_ops = &nfsd4_umh_tracking_ops;
+	status = nn->client_tracking_ops->init(net);
+	if (!status)
+		return status;
+
+	/*
+	 * Finally, See if the recoverydir exists and is a directory.
+	 * If it is, then use the legacy ops.
+	 */
+	nn->client_tracking_ops = &nfsd4_legacy_tracking_ops;
+	status = kern_path(nfs4_recoverydir(), LOOKUP_FOLLOW, &path);
+	if (!status) {
+		status = d_is_dir(path.dentry);
+		path_put(&path);
+		if (!status) {
+			status = -EINVAL;
+			goto out;
+		}
+	}
+
+do_init:
+	status = nn->client_tracking_ops->init(net);
+out:
+	if (status) {
+		printk(KERN_WARNING "NFSD: Unable to initialize client "
+				    "recovery tracking! (%d)\n", status);
+		nn->client_tracking_ops = NULL;
+	}
+	return status;
+}
+
+void
+nfsd4_client_tracking_exit(struct net *net)
+{
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+
+	if (nn->client_tracking_ops) {
+		if (nn->client_tracking_ops->exit)
+			nn->client_tracking_ops->exit(net);
+		nn->client_tracking_ops = NULL;
+	}
+}
+
+void
+nfsd4_client_record_create(struct nfs4_client *clp)
+{
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+
+	if (nn->client_tracking_ops)
+		nn->client_tracking_ops->create(clp);
+}
+
+void
+nfsd4_client_record_remove(struct nfs4_client *clp)
+{
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+
+	if (nn->client_tracking_ops)
+		nn->client_tracking_ops->remove(clp);
+}
+
+int
+nfsd4_client_record_check(struct nfs4_client *clp)
+{
+	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+
+	if (nn->client_tracking_ops)
+		return nn->client_tracking_ops->check(clp);
+
+	return -EOPNOTSUPP;
+}
+
+void
+nfsd4_record_grace_done(struct nfsd_net *nn)
+{
+	if (nn->client_tracking_ops)
+		nn->client_tracking_ops->grace_done(nn);
+}
+
+static int
+rpc_pipefs_event(struct notifier_block *nb, unsigned long event, void *ptr)
+{
+	struct super_block *sb = ptr;
+	struct net *net = sb->s_fs_info;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	struct cld_net *cn = nn->cld_net;
+	struct dentry *dentry;
+	int ret = 0;
+
+	if (!try_module_get(THIS_MODULE))
+		return 0;
+
+	if (!cn) {
+		module_put(THIS_MODULE);
+		return 0;
+	}
+
+	switch (event) {
+	case RPC_PIPEFS_MOUNT:
+		dentry = nfsd4_cld_register_sb(sb, cn->cn_pipe);
+		if (IS_ERR(dentry)) {
+			ret = PTR_ERR(dentry);
+			break;
+		}
+		cn->cn_pipe->dentry = dentry;
+		break;
+	case RPC_PIPEFS_UMOUNT:
+		if (cn->cn_pipe->dentry)
+			nfsd4_cld_unregister_sb(cn->cn_pipe);
+		break;
+	default:
+		ret = -ENOTSUPP;
+		break;
+	}
+	module_put(THIS_MODULE);
+	return ret;
+}
+
+static struct notifier_block nfsd4_cld_block = {
+	.notifier_call = rpc_pipefs_event,
+};
+
+int
+register_cld_notifier(void)
+{
+	WARN_ON(!nfsd_net_id);
+	return rpc_pipefs_notifier_register(&nfsd4_cld_block);
+}
+
+void
+unregister_cld_notifier(void)
+{
+	rpc_pipefs_notifier_unregister(&nfsd4_cld_block);
+}