1/*
2*  Copyright (c) 2004 The Regents of the University of Michigan.
3*  Copyright (c) 2012 Jeff Layton <jlayton@redhat.com>
4*  All rights reserved.
5*
6*  Andy Adamson <andros@citi.umich.edu>
7*
8*  Redistribution and use in source and binary forms, with or without
9*  modification, are permitted provided that the following conditions
10*  are met:
11*
12*  1. Redistributions of source code must retain the above copyright
13*     notice, this list of conditions and the following disclaimer.
14*  2. Redistributions in binary form must reproduce the above copyright
15*     notice, this list of conditions and the following disclaimer in the
16*     documentation and/or other materials provided with the distribution.
17*  3. Neither the name of the University nor the names of its
18*     contributors may be used to endorse or promote products derived
19*     from this software without specific prior written permission.
20*
21*  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
22*  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
23*  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
24*  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25*  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26*  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27*  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
28*  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
29*  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
30*  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
31*  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32*
33*/
34
35#include <linux/file.h>
36#include <linux/slab.h>
37#include <linux/namei.h>
38#include <linux/crypto.h>
39#include <linux/sched.h>
40#include <linux/fs.h>
41#include <linux/module.h>
42#include <net/net_namespace.h>
43#include <linux/sunrpc/rpc_pipe_fs.h>
44#include <linux/sunrpc/clnt.h>
45#include <linux/nfsd/cld.h>
46
47#include "nfsd.h"
48#include "state.h"
49#include "vfs.h"
50#include "netns.h"
51
52#define NFSDDBG_FACILITY                NFSDDBG_PROC
53
54/* Declarations */
55struct nfsd4_client_tracking_ops {
56	int (*init)(struct net *);
57	void (*exit)(struct net *);
58	void (*create)(struct nfs4_client *);
59	void (*remove)(struct nfs4_client *);
60	int (*check)(struct nfs4_client *);
61	void (*grace_done)(struct nfsd_net *);
62};
63
64/* Globals */
65static char user_recovery_dirname[PATH_MAX] = "/var/lib/nfs/v4recovery";
66
67static int
68nfs4_save_creds(const struct cred **original_creds)
69{
70	struct cred *new;
71
72	new = prepare_creds();
73	if (!new)
74		return -ENOMEM;
75
76	new->fsuid = GLOBAL_ROOT_UID;
77	new->fsgid = GLOBAL_ROOT_GID;
78	*original_creds = override_creds(new);
79	put_cred(new);
80	return 0;
81}
82
83static void
84nfs4_reset_creds(const struct cred *original)
85{
86	revert_creds(original);
87}
88
89static void
90md5_to_hex(char *out, char *md5)
91{
92	int i;
93
94	for (i=0; i<16; i++) {
95		unsigned char c = md5[i];
96
97		*out++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
98		*out++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
99	}
100	*out = '\0';
101}
102
103static int
104nfs4_make_rec_clidname(char *dname, const struct xdr_netobj *clname)
105{
106	struct xdr_netobj cksum;
107	struct hash_desc desc;
108	struct scatterlist sg;
109	int status;
110
111	dprintk("NFSD: nfs4_make_rec_clidname for %.*s\n",
112			clname->len, clname->data);
113	desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
114	desc.tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
115	if (IS_ERR(desc.tfm)) {
116		status = PTR_ERR(desc.tfm);
117		goto out_no_tfm;
118	}
119
120	cksum.len = crypto_hash_digestsize(desc.tfm);
121	cksum.data = kmalloc(cksum.len, GFP_KERNEL);
122	if (cksum.data == NULL) {
123		status = -ENOMEM;
124 		goto out;
125	}
126
127	sg_init_one(&sg, clname->data, clname->len);
128
129	status = crypto_hash_digest(&desc, &sg, sg.length, cksum.data);
130	if (status)
131		goto out;
132
133	md5_to_hex(dname, cksum.data);
134
135	status = 0;
136out:
137	kfree(cksum.data);
138	crypto_free_hash(desc.tfm);
139out_no_tfm:
140	return status;
141}
142
143/*
144 * If we had an error generating the recdir name for the legacy tracker
145 * then warn the admin. If the error doesn't appear to be transient,
146 * then disable recovery tracking.
147 */
148static void
149legacy_recdir_name_error(struct nfs4_client *clp, int error)
150{
151	printk(KERN_ERR "NFSD: unable to generate recoverydir "
152			"name (%d).\n", error);
153
154	/*
155	 * if the algorithm just doesn't exist, then disable the recovery
156	 * tracker altogether. The crypto libs will generally return this if
157	 * FIPS is enabled as well.
158	 */
159	if (error == -ENOENT) {
160		printk(KERN_ERR "NFSD: disabling legacy clientid tracking. "
161			"Reboot recovery will not function correctly!\n");
162		nfsd4_client_tracking_exit(clp->net);
163	}
164}
165
166static void
167nfsd4_create_clid_dir(struct nfs4_client *clp)
168{
169	const struct cred *original_cred;
170	char dname[HEXDIR_LEN];
171	struct dentry *dir, *dentry;
172	struct nfs4_client_reclaim *crp;
173	int status;
174	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
175
176	if (test_and_set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
177		return;
178	if (!nn->rec_file)
179		return;
180
181	status = nfs4_make_rec_clidname(dname, &clp->cl_name);
182	if (status)
183		return legacy_recdir_name_error(clp, status);
184
185	status = nfs4_save_creds(&original_cred);
186	if (status < 0)
187		return;
188
189	status = mnt_want_write_file(nn->rec_file);
190	if (status)
191		goto out_creds;
192
193	dir = nn->rec_file->f_path.dentry;
194	/* lock the parent */
195	mutex_lock(&d_inode(dir)->i_mutex);
196
197	dentry = lookup_one_len(dname, dir, HEXDIR_LEN-1);
198	if (IS_ERR(dentry)) {
199		status = PTR_ERR(dentry);
200		goto out_unlock;
201	}
202	if (d_really_is_positive(dentry))
203		/*
204		 * In the 4.1 case, where we're called from
205		 * reclaim_complete(), records from the previous reboot
206		 * may still be left, so this is OK.
207		 *
208		 * In the 4.0 case, we should never get here; but we may
209		 * as well be forgiving and just succeed silently.
210		 */
211		goto out_put;
212	status = vfs_mkdir(d_inode(dir), dentry, S_IRWXU);
213out_put:
214	dput(dentry);
215out_unlock:
216	mutex_unlock(&d_inode(dir)->i_mutex);
217	if (status == 0) {
218		if (nn->in_grace) {
219			crp = nfs4_client_to_reclaim(dname, nn);
220			if (crp)
221				crp->cr_clp = clp;
222		}
223		vfs_fsync(nn->rec_file, 0);
224	} else {
225		printk(KERN_ERR "NFSD: failed to write recovery record"
226				" (err %d); please check that %s exists"
227				" and is writeable", status,
228				user_recovery_dirname);
229	}
230	mnt_drop_write_file(nn->rec_file);
231out_creds:
232	nfs4_reset_creds(original_cred);
233}
234
235typedef int (recdir_func)(struct dentry *, struct dentry *, struct nfsd_net *);
236
237struct name_list {
238	char name[HEXDIR_LEN];
239	struct list_head list;
240};
241
242struct nfs4_dir_ctx {
243	struct dir_context ctx;
244	struct list_head names;
245};
246
247static int
248nfsd4_build_namelist(struct dir_context *__ctx, const char *name, int namlen,
249		loff_t offset, u64 ino, unsigned int d_type)
250{
251	struct nfs4_dir_ctx *ctx =
252		container_of(__ctx, struct nfs4_dir_ctx, ctx);
253	struct name_list *entry;
254
255	if (namlen != HEXDIR_LEN - 1)
256		return 0;
257	entry = kmalloc(sizeof(struct name_list), GFP_KERNEL);
258	if (entry == NULL)
259		return -ENOMEM;
260	memcpy(entry->name, name, HEXDIR_LEN - 1);
261	entry->name[HEXDIR_LEN - 1] = '\0';
262	list_add(&entry->list, &ctx->names);
263	return 0;
264}
265
266static int
267nfsd4_list_rec_dir(recdir_func *f, struct nfsd_net *nn)
268{
269	const struct cred *original_cred;
270	struct dentry *dir = nn->rec_file->f_path.dentry;
271	struct nfs4_dir_ctx ctx = {
272		.ctx.actor = nfsd4_build_namelist,
273		.names = LIST_HEAD_INIT(ctx.names)
274	};
275	int status;
276
277	status = nfs4_save_creds(&original_cred);
278	if (status < 0)
279		return status;
280
281	status = vfs_llseek(nn->rec_file, 0, SEEK_SET);
282	if (status < 0) {
283		nfs4_reset_creds(original_cred);
284		return status;
285	}
286
287	status = iterate_dir(nn->rec_file, &ctx.ctx);
288	mutex_lock_nested(&d_inode(dir)->i_mutex, I_MUTEX_PARENT);
289	while (!list_empty(&ctx.names)) {
290		struct name_list *entry;
291		entry = list_entry(ctx.names.next, struct name_list, list);
292		if (!status) {
293			struct dentry *dentry;
294			dentry = lookup_one_len(entry->name, dir, HEXDIR_LEN-1);
295			if (IS_ERR(dentry)) {
296				status = PTR_ERR(dentry);
297				break;
298			}
299			status = f(dir, dentry, nn);
300			dput(dentry);
301		}
302		list_del(&entry->list);
303		kfree(entry);
304	}
305	mutex_unlock(&d_inode(dir)->i_mutex);
306	nfs4_reset_creds(original_cred);
307	return status;
308}
309
310static int
311nfsd4_unlink_clid_dir(char *name, int namlen, struct nfsd_net *nn)
312{
313	struct dentry *dir, *dentry;
314	int status;
315
316	dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
317
318	dir = nn->rec_file->f_path.dentry;
319	mutex_lock_nested(&d_inode(dir)->i_mutex, I_MUTEX_PARENT);
320	dentry = lookup_one_len(name, dir, namlen);
321	if (IS_ERR(dentry)) {
322		status = PTR_ERR(dentry);
323		goto out_unlock;
324	}
325	status = -ENOENT;
326	if (d_really_is_negative(dentry))
327		goto out;
328	status = vfs_rmdir(d_inode(dir), dentry);
329out:
330	dput(dentry);
331out_unlock:
332	mutex_unlock(&d_inode(dir)->i_mutex);
333	return status;
334}
335
336static void
337nfsd4_remove_clid_dir(struct nfs4_client *clp)
338{
339	const struct cred *original_cred;
340	struct nfs4_client_reclaim *crp;
341	char dname[HEXDIR_LEN];
342	int status;
343	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
344
345	if (!nn->rec_file || !test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
346		return;
347
348	status = nfs4_make_rec_clidname(dname, &clp->cl_name);
349	if (status)
350		return legacy_recdir_name_error(clp, status);
351
352	status = mnt_want_write_file(nn->rec_file);
353	if (status)
354		goto out;
355	clear_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
356
357	status = nfs4_save_creds(&original_cred);
358	if (status < 0)
359		goto out_drop_write;
360
361	status = nfsd4_unlink_clid_dir(dname, HEXDIR_LEN-1, nn);
362	nfs4_reset_creds(original_cred);
363	if (status == 0) {
364		vfs_fsync(nn->rec_file, 0);
365		if (nn->in_grace) {
366			/* remove reclaim record */
367			crp = nfsd4_find_reclaim_client(dname, nn);
368			if (crp)
369				nfs4_remove_reclaim_record(crp, nn);
370		}
371	}
372out_drop_write:
373	mnt_drop_write_file(nn->rec_file);
374out:
375	if (status)
376		printk("NFSD: Failed to remove expired client state directory"
377				" %.*s\n", HEXDIR_LEN, dname);
378}
379
380static int
381purge_old(struct dentry *parent, struct dentry *child, struct nfsd_net *nn)
382{
383	int status;
384
385	if (nfs4_has_reclaimed_state(child->d_name.name, nn))
386		return 0;
387
388	status = vfs_rmdir(d_inode(parent), child);
389	if (status)
390		printk("failed to remove client recovery directory %pd\n",
391				child);
392	/* Keep trying, success or failure: */
393	return 0;
394}
395
396static void
397nfsd4_recdir_purge_old(struct nfsd_net *nn)
398{
399	int status;
400
401	nn->in_grace = false;
402	if (!nn->rec_file)
403		return;
404	status = mnt_want_write_file(nn->rec_file);
405	if (status)
406		goto out;
407	status = nfsd4_list_rec_dir(purge_old, nn);
408	if (status == 0)
409		vfs_fsync(nn->rec_file, 0);
410	mnt_drop_write_file(nn->rec_file);
411out:
412	nfs4_release_reclaim(nn);
413	if (status)
414		printk("nfsd4: failed to purge old clients from recovery"
415			" directory %pD\n", nn->rec_file);
416}
417
418static int
419load_recdir(struct dentry *parent, struct dentry *child, struct nfsd_net *nn)
420{
421	if (child->d_name.len != HEXDIR_LEN - 1) {
422		printk("nfsd4: illegal name %pd in recovery directory\n",
423				child);
424		/* Keep trying; maybe the others are OK: */
425		return 0;
426	}
427	nfs4_client_to_reclaim(child->d_name.name, nn);
428	return 0;
429}
430
431static int
432nfsd4_recdir_load(struct net *net) {
433	int status;
434	struct nfsd_net *nn =  net_generic(net, nfsd_net_id);
435
436	if (!nn->rec_file)
437		return 0;
438
439	status = nfsd4_list_rec_dir(load_recdir, nn);
440	if (status)
441		printk("nfsd4: failed loading clients from recovery"
442			" directory %pD\n", nn->rec_file);
443	return status;
444}
445
446/*
447 * Hold reference to the recovery directory.
448 */
449
450static int
451nfsd4_init_recdir(struct net *net)
452{
453	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
454	const struct cred *original_cred;
455	int status;
456
457	printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
458			user_recovery_dirname);
459
460	BUG_ON(nn->rec_file);
461
462	status = nfs4_save_creds(&original_cred);
463	if (status < 0) {
464		printk("NFSD: Unable to change credentials to find recovery"
465		       " directory: error %d\n",
466		       status);
467		return status;
468	}
469
470	nn->rec_file = filp_open(user_recovery_dirname, O_RDONLY | O_DIRECTORY, 0);
471	if (IS_ERR(nn->rec_file)) {
472		printk("NFSD: unable to find recovery directory %s\n",
473				user_recovery_dirname);
474		status = PTR_ERR(nn->rec_file);
475		nn->rec_file = NULL;
476	}
477
478	nfs4_reset_creds(original_cred);
479	if (!status)
480		nn->in_grace = true;
481	return status;
482}
483
484static void
485nfsd4_shutdown_recdir(struct net *net)
486{
487	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
488
489	if (!nn->rec_file)
490		return;
491	fput(nn->rec_file);
492	nn->rec_file = NULL;
493}
494
495static int
496nfs4_legacy_state_init(struct net *net)
497{
498	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
499	int i;
500
501	nn->reclaim_str_hashtbl = kmalloc(sizeof(struct list_head) *
502					  CLIENT_HASH_SIZE, GFP_KERNEL);
503	if (!nn->reclaim_str_hashtbl)
504		return -ENOMEM;
505
506	for (i = 0; i < CLIENT_HASH_SIZE; i++)
507		INIT_LIST_HEAD(&nn->reclaim_str_hashtbl[i]);
508	nn->reclaim_str_hashtbl_size = 0;
509
510	return 0;
511}
512
513static void
514nfs4_legacy_state_shutdown(struct net *net)
515{
516	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
517
518	kfree(nn->reclaim_str_hashtbl);
519}
520
521static int
522nfsd4_load_reboot_recovery_data(struct net *net)
523{
524	int status;
525
526	status = nfsd4_init_recdir(net);
527	if (status)
528		return status;
529
530	status = nfsd4_recdir_load(net);
531	if (status)
532		nfsd4_shutdown_recdir(net);
533
534	return status;
535}
536
537static int
538nfsd4_legacy_tracking_init(struct net *net)
539{
540	int status;
541
542	/* XXX: The legacy code won't work in a container */
543	if (net != &init_net) {
544		WARN(1, KERN_ERR "NFSD: attempt to initialize legacy client "
545			"tracking in a container!\n");
546		return -EINVAL;
547	}
548
549	status = nfs4_legacy_state_init(net);
550	if (status)
551		return status;
552
553	status = nfsd4_load_reboot_recovery_data(net);
554	if (status)
555		goto err;
556	return 0;
557
558err:
559	nfs4_legacy_state_shutdown(net);
560	return status;
561}
562
563static void
564nfsd4_legacy_tracking_exit(struct net *net)
565{
566	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
567
568	nfs4_release_reclaim(nn);
569	nfsd4_shutdown_recdir(net);
570	nfs4_legacy_state_shutdown(net);
571}
572
573/*
574 * Change the NFSv4 recovery directory to recdir.
575 */
576int
577nfs4_reset_recoverydir(char *recdir)
578{
579	int status;
580	struct path path;
581
582	status = kern_path(recdir, LOOKUP_FOLLOW, &path);
583	if (status)
584		return status;
585	status = -ENOTDIR;
586	if (d_is_dir(path.dentry)) {
587		strcpy(user_recovery_dirname, recdir);
588		status = 0;
589	}
590	path_put(&path);
591	return status;
592}
593
594char *
595nfs4_recoverydir(void)
596{
597	return user_recovery_dirname;
598}
599
600static int
601nfsd4_check_legacy_client(struct nfs4_client *clp)
602{
603	int status;
604	char dname[HEXDIR_LEN];
605	struct nfs4_client_reclaim *crp;
606	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
607
608	/* did we already find that this client is stable? */
609	if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
610		return 0;
611
612	status = nfs4_make_rec_clidname(dname, &clp->cl_name);
613	if (status) {
614		legacy_recdir_name_error(clp, status);
615		return status;
616	}
617
618	/* look for it in the reclaim hashtable otherwise */
619	crp = nfsd4_find_reclaim_client(dname, nn);
620	if (crp) {
621		set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
622		crp->cr_clp = clp;
623		return 0;
624	}
625
626	return -ENOENT;
627}
628
629static struct nfsd4_client_tracking_ops nfsd4_legacy_tracking_ops = {
630	.init		= nfsd4_legacy_tracking_init,
631	.exit		= nfsd4_legacy_tracking_exit,
632	.create		= nfsd4_create_clid_dir,
633	.remove		= nfsd4_remove_clid_dir,
634	.check		= nfsd4_check_legacy_client,
635	.grace_done	= nfsd4_recdir_purge_old,
636};
637
638/* Globals */
639#define NFSD_PIPE_DIR		"nfsd"
640#define NFSD_CLD_PIPE		"cld"
641
642/* per-net-ns structure for holding cld upcall info */
643struct cld_net {
644	struct rpc_pipe		*cn_pipe;
645	spinlock_t		 cn_lock;
646	struct list_head	 cn_list;
647	unsigned int		 cn_xid;
648};
649
650struct cld_upcall {
651	struct list_head	 cu_list;
652	struct cld_net		*cu_net;
653	struct task_struct	*cu_task;
654	struct cld_msg		 cu_msg;
655};
656
657static int
658__cld_pipe_upcall(struct rpc_pipe *pipe, struct cld_msg *cmsg)
659{
660	int ret;
661	struct rpc_pipe_msg msg;
662
663	memset(&msg, 0, sizeof(msg));
664	msg.data = cmsg;
665	msg.len = sizeof(*cmsg);
666
667	/*
668	 * Set task state before we queue the upcall. That prevents
669	 * wake_up_process in the downcall from racing with schedule.
670	 */
671	set_current_state(TASK_UNINTERRUPTIBLE);
672	ret = rpc_queue_upcall(pipe, &msg);
673	if (ret < 0) {
674		set_current_state(TASK_RUNNING);
675		goto out;
676	}
677
678	schedule();
679
680	if (msg.errno < 0)
681		ret = msg.errno;
682out:
683	return ret;
684}
685
686static int
687cld_pipe_upcall(struct rpc_pipe *pipe, struct cld_msg *cmsg)
688{
689	int ret;
690
691	/*
692	 * -EAGAIN occurs when pipe is closed and reopened while there are
693	 *  upcalls queued.
694	 */
695	do {
696		ret = __cld_pipe_upcall(pipe, cmsg);
697	} while (ret == -EAGAIN);
698
699	return ret;
700}
701
702static ssize_t
703cld_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
704{
705	struct cld_upcall *tmp, *cup;
706	struct cld_msg __user *cmsg = (struct cld_msg __user *)src;
707	uint32_t xid;
708	struct nfsd_net *nn = net_generic(file_inode(filp)->i_sb->s_fs_info,
709						nfsd_net_id);
710	struct cld_net *cn = nn->cld_net;
711
712	if (mlen != sizeof(*cmsg)) {
713		dprintk("%s: got %zu bytes, expected %zu\n", __func__, mlen,
714			sizeof(*cmsg));
715		return -EINVAL;
716	}
717
718	/* copy just the xid so we can try to find that */
719	if (copy_from_user(&xid, &cmsg->cm_xid, sizeof(xid)) != 0) {
720		dprintk("%s: error when copying xid from userspace", __func__);
721		return -EFAULT;
722	}
723
724	/* walk the list and find corresponding xid */
725	cup = NULL;
726	spin_lock(&cn->cn_lock);
727	list_for_each_entry(tmp, &cn->cn_list, cu_list) {
728		if (get_unaligned(&tmp->cu_msg.cm_xid) == xid) {
729			cup = tmp;
730			list_del_init(&cup->cu_list);
731			break;
732		}
733	}
734	spin_unlock(&cn->cn_lock);
735
736	/* couldn't find upcall? */
737	if (!cup) {
738		dprintk("%s: couldn't find upcall -- xid=%u\n", __func__, xid);
739		return -EINVAL;
740	}
741
742	if (copy_from_user(&cup->cu_msg, src, mlen) != 0)
743		return -EFAULT;
744
745	wake_up_process(cup->cu_task);
746	return mlen;
747}
748
749static void
750cld_pipe_destroy_msg(struct rpc_pipe_msg *msg)
751{
752	struct cld_msg *cmsg = msg->data;
753	struct cld_upcall *cup = container_of(cmsg, struct cld_upcall,
754						 cu_msg);
755
756	/* errno >= 0 means we got a downcall */
757	if (msg->errno >= 0)
758		return;
759
760	wake_up_process(cup->cu_task);
761}
762
763static const struct rpc_pipe_ops cld_upcall_ops = {
764	.upcall		= rpc_pipe_generic_upcall,
765	.downcall	= cld_pipe_downcall,
766	.destroy_msg	= cld_pipe_destroy_msg,
767};
768
769static struct dentry *
770nfsd4_cld_register_sb(struct super_block *sb, struct rpc_pipe *pipe)
771{
772	struct dentry *dir, *dentry;
773
774	dir = rpc_d_lookup_sb(sb, NFSD_PIPE_DIR);
775	if (dir == NULL)
776		return ERR_PTR(-ENOENT);
777	dentry = rpc_mkpipe_dentry(dir, NFSD_CLD_PIPE, NULL, pipe);
778	dput(dir);
779	return dentry;
780}
781
782static void
783nfsd4_cld_unregister_sb(struct rpc_pipe *pipe)
784{
785	if (pipe->dentry)
786		rpc_unlink(pipe->dentry);
787}
788
789static struct dentry *
790nfsd4_cld_register_net(struct net *net, struct rpc_pipe *pipe)
791{
792	struct super_block *sb;
793	struct dentry *dentry;
794
795	sb = rpc_get_sb_net(net);
796	if (!sb)
797		return NULL;
798	dentry = nfsd4_cld_register_sb(sb, pipe);
799	rpc_put_sb_net(net);
800	return dentry;
801}
802
803static void
804nfsd4_cld_unregister_net(struct net *net, struct rpc_pipe *pipe)
805{
806	struct super_block *sb;
807
808	sb = rpc_get_sb_net(net);
809	if (sb) {
810		nfsd4_cld_unregister_sb(pipe);
811		rpc_put_sb_net(net);
812	}
813}
814
815/* Initialize rpc_pipefs pipe for communication with client tracking daemon */
816static int
817nfsd4_init_cld_pipe(struct net *net)
818{
819	int ret;
820	struct dentry *dentry;
821	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
822	struct cld_net *cn;
823
824	if (nn->cld_net)
825		return 0;
826
827	cn = kzalloc(sizeof(*cn), GFP_KERNEL);
828	if (!cn) {
829		ret = -ENOMEM;
830		goto err;
831	}
832
833	cn->cn_pipe = rpc_mkpipe_data(&cld_upcall_ops, RPC_PIPE_WAIT_FOR_OPEN);
834	if (IS_ERR(cn->cn_pipe)) {
835		ret = PTR_ERR(cn->cn_pipe);
836		goto err;
837	}
838	spin_lock_init(&cn->cn_lock);
839	INIT_LIST_HEAD(&cn->cn_list);
840
841	dentry = nfsd4_cld_register_net(net, cn->cn_pipe);
842	if (IS_ERR(dentry)) {
843		ret = PTR_ERR(dentry);
844		goto err_destroy_data;
845	}
846
847	cn->cn_pipe->dentry = dentry;
848	nn->cld_net = cn;
849	return 0;
850
851err_destroy_data:
852	rpc_destroy_pipe_data(cn->cn_pipe);
853err:
854	kfree(cn);
855	printk(KERN_ERR "NFSD: unable to create nfsdcld upcall pipe (%d)\n",
856			ret);
857	return ret;
858}
859
860static void
861nfsd4_remove_cld_pipe(struct net *net)
862{
863	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
864	struct cld_net *cn = nn->cld_net;
865
866	nfsd4_cld_unregister_net(net, cn->cn_pipe);
867	rpc_destroy_pipe_data(cn->cn_pipe);
868	kfree(nn->cld_net);
869	nn->cld_net = NULL;
870}
871
872static struct cld_upcall *
873alloc_cld_upcall(struct cld_net *cn)
874{
875	struct cld_upcall *new, *tmp;
876
877	new = kzalloc(sizeof(*new), GFP_KERNEL);
878	if (!new)
879		return new;
880
881	/* FIXME: hard cap on number in flight? */
882restart_search:
883	spin_lock(&cn->cn_lock);
884	list_for_each_entry(tmp, &cn->cn_list, cu_list) {
885		if (tmp->cu_msg.cm_xid == cn->cn_xid) {
886			cn->cn_xid++;
887			spin_unlock(&cn->cn_lock);
888			goto restart_search;
889		}
890	}
891	new->cu_task = current;
892	new->cu_msg.cm_vers = CLD_UPCALL_VERSION;
893	put_unaligned(cn->cn_xid++, &new->cu_msg.cm_xid);
894	new->cu_net = cn;
895	list_add(&new->cu_list, &cn->cn_list);
896	spin_unlock(&cn->cn_lock);
897
898	dprintk("%s: allocated xid %u\n", __func__, new->cu_msg.cm_xid);
899
900	return new;
901}
902
903static void
904free_cld_upcall(struct cld_upcall *victim)
905{
906	struct cld_net *cn = victim->cu_net;
907
908	spin_lock(&cn->cn_lock);
909	list_del(&victim->cu_list);
910	spin_unlock(&cn->cn_lock);
911	kfree(victim);
912}
913
914/* Ask daemon to create a new record */
915static void
916nfsd4_cld_create(struct nfs4_client *clp)
917{
918	int ret;
919	struct cld_upcall *cup;
920	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
921	struct cld_net *cn = nn->cld_net;
922
923	/* Don't upcall if it's already stored */
924	if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
925		return;
926
927	cup = alloc_cld_upcall(cn);
928	if (!cup) {
929		ret = -ENOMEM;
930		goto out_err;
931	}
932
933	cup->cu_msg.cm_cmd = Cld_Create;
934	cup->cu_msg.cm_u.cm_name.cn_len = clp->cl_name.len;
935	memcpy(cup->cu_msg.cm_u.cm_name.cn_id, clp->cl_name.data,
936			clp->cl_name.len);
937
938	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_msg);
939	if (!ret) {
940		ret = cup->cu_msg.cm_status;
941		set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
942	}
943
944	free_cld_upcall(cup);
945out_err:
946	if (ret)
947		printk(KERN_ERR "NFSD: Unable to create client "
948				"record on stable storage: %d\n", ret);
949}
950
951/* Ask daemon to create a new record */
952static void
953nfsd4_cld_remove(struct nfs4_client *clp)
954{
955	int ret;
956	struct cld_upcall *cup;
957	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
958	struct cld_net *cn = nn->cld_net;
959
960	/* Don't upcall if it's already removed */
961	if (!test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
962		return;
963
964	cup = alloc_cld_upcall(cn);
965	if (!cup) {
966		ret = -ENOMEM;
967		goto out_err;
968	}
969
970	cup->cu_msg.cm_cmd = Cld_Remove;
971	cup->cu_msg.cm_u.cm_name.cn_len = clp->cl_name.len;
972	memcpy(cup->cu_msg.cm_u.cm_name.cn_id, clp->cl_name.data,
973			clp->cl_name.len);
974
975	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_msg);
976	if (!ret) {
977		ret = cup->cu_msg.cm_status;
978		clear_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
979	}
980
981	free_cld_upcall(cup);
982out_err:
983	if (ret)
984		printk(KERN_ERR "NFSD: Unable to remove client "
985				"record from stable storage: %d\n", ret);
986}
987
988/* Check for presence of a record, and update its timestamp */
989static int
990nfsd4_cld_check(struct nfs4_client *clp)
991{
992	int ret;
993	struct cld_upcall *cup;
994	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
995	struct cld_net *cn = nn->cld_net;
996
997	/* Don't upcall if one was already stored during this grace pd */
998	if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
999		return 0;
1000
1001	cup = alloc_cld_upcall(cn);
1002	if (!cup) {
1003		printk(KERN_ERR "NFSD: Unable to check client record on "
1004				"stable storage: %d\n", -ENOMEM);
1005		return -ENOMEM;
1006	}
1007
1008	cup->cu_msg.cm_cmd = Cld_Check;
1009	cup->cu_msg.cm_u.cm_name.cn_len = clp->cl_name.len;
1010	memcpy(cup->cu_msg.cm_u.cm_name.cn_id, clp->cl_name.data,
1011			clp->cl_name.len);
1012
1013	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_msg);
1014	if (!ret) {
1015		ret = cup->cu_msg.cm_status;
1016		set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
1017	}
1018
1019	free_cld_upcall(cup);
1020	return ret;
1021}
1022
1023static void
1024nfsd4_cld_grace_done(struct nfsd_net *nn)
1025{
1026	int ret;
1027	struct cld_upcall *cup;
1028	struct cld_net *cn = nn->cld_net;
1029
1030	cup = alloc_cld_upcall(cn);
1031	if (!cup) {
1032		ret = -ENOMEM;
1033		goto out_err;
1034	}
1035
1036	cup->cu_msg.cm_cmd = Cld_GraceDone;
1037	cup->cu_msg.cm_u.cm_gracetime = (int64_t)nn->boot_time;
1038	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_msg);
1039	if (!ret)
1040		ret = cup->cu_msg.cm_status;
1041
1042	free_cld_upcall(cup);
1043out_err:
1044	if (ret)
1045		printk(KERN_ERR "NFSD: Unable to end grace period: %d\n", ret);
1046}
1047
1048static struct nfsd4_client_tracking_ops nfsd4_cld_tracking_ops = {
1049	.init		= nfsd4_init_cld_pipe,
1050	.exit		= nfsd4_remove_cld_pipe,
1051	.create		= nfsd4_cld_create,
1052	.remove		= nfsd4_cld_remove,
1053	.check		= nfsd4_cld_check,
1054	.grace_done	= nfsd4_cld_grace_done,
1055};
1056
1057/* upcall via usermodehelper */
1058static char cltrack_prog[PATH_MAX] = "/sbin/nfsdcltrack";
1059module_param_string(cltrack_prog, cltrack_prog, sizeof(cltrack_prog),
1060			S_IRUGO|S_IWUSR);
1061MODULE_PARM_DESC(cltrack_prog, "Path to the nfsdcltrack upcall program");
1062
1063static bool cltrack_legacy_disable;
1064module_param(cltrack_legacy_disable, bool, S_IRUGO|S_IWUSR);
1065MODULE_PARM_DESC(cltrack_legacy_disable,
1066		"Disable legacy recoverydir conversion. Default: false");
1067
1068#define LEGACY_TOPDIR_ENV_PREFIX "NFSDCLTRACK_LEGACY_TOPDIR="
1069#define LEGACY_RECDIR_ENV_PREFIX "NFSDCLTRACK_LEGACY_RECDIR="
1070#define HAS_SESSION_ENV_PREFIX "NFSDCLTRACK_CLIENT_HAS_SESSION="
1071#define GRACE_START_ENV_PREFIX "NFSDCLTRACK_GRACE_START="
1072
1073static char *
1074nfsd4_cltrack_legacy_topdir(void)
1075{
1076	int copied;
1077	size_t len;
1078	char *result;
1079
1080	if (cltrack_legacy_disable)
1081		return NULL;
1082
1083	len = strlen(LEGACY_TOPDIR_ENV_PREFIX) +
1084		strlen(nfs4_recoverydir()) + 1;
1085
1086	result = kmalloc(len, GFP_KERNEL);
1087	if (!result)
1088		return result;
1089
1090	copied = snprintf(result, len, LEGACY_TOPDIR_ENV_PREFIX "%s",
1091				nfs4_recoverydir());
1092	if (copied >= len) {
1093		/* just return nothing if output was truncated */
1094		kfree(result);
1095		return NULL;
1096	}
1097
1098	return result;
1099}
1100
1101static char *
1102nfsd4_cltrack_legacy_recdir(const struct xdr_netobj *name)
1103{
1104	int copied;
1105	size_t len;
1106	char *result;
1107
1108	if (cltrack_legacy_disable)
1109		return NULL;
1110
1111	/* +1 is for '/' between "topdir" and "recdir" */
1112	len = strlen(LEGACY_RECDIR_ENV_PREFIX) +
1113		strlen(nfs4_recoverydir()) + 1 + HEXDIR_LEN;
1114
1115	result = kmalloc(len, GFP_KERNEL);
1116	if (!result)
1117		return result;
1118
1119	copied = snprintf(result, len, LEGACY_RECDIR_ENV_PREFIX "%s/",
1120				nfs4_recoverydir());
1121	if (copied > (len - HEXDIR_LEN)) {
1122		/* just return nothing if output will be truncated */
1123		kfree(result);
1124		return NULL;
1125	}
1126
1127	copied = nfs4_make_rec_clidname(result + copied, name);
1128	if (copied) {
1129		kfree(result);
1130		return NULL;
1131	}
1132
1133	return result;
1134}
1135
1136static char *
1137nfsd4_cltrack_client_has_session(struct nfs4_client *clp)
1138{
1139	int copied;
1140	size_t len;
1141	char *result;
1142
1143	/* prefix + Y/N character + terminating NULL */
1144	len = strlen(HAS_SESSION_ENV_PREFIX) + 1 + 1;
1145
1146	result = kmalloc(len, GFP_KERNEL);
1147	if (!result)
1148		return result;
1149
1150	copied = snprintf(result, len, HAS_SESSION_ENV_PREFIX "%c",
1151				clp->cl_minorversion ? 'Y' : 'N');
1152	if (copied >= len) {
1153		/* just return nothing if output was truncated */
1154		kfree(result);
1155		return NULL;
1156	}
1157
1158	return result;
1159}
1160
1161static char *
1162nfsd4_cltrack_grace_start(time_t grace_start)
1163{
1164	int copied;
1165	size_t len;
1166	char *result;
1167
1168	/* prefix + max width of int64_t string + terminating NULL */
1169	len = strlen(GRACE_START_ENV_PREFIX) + 22 + 1;
1170
1171	result = kmalloc(len, GFP_KERNEL);
1172	if (!result)
1173		return result;
1174
1175	copied = snprintf(result, len, GRACE_START_ENV_PREFIX "%ld",
1176				grace_start);
1177	if (copied >= len) {
1178		/* just return nothing if output was truncated */
1179		kfree(result);
1180		return NULL;
1181	}
1182
1183	return result;
1184}
1185
1186static int
1187nfsd4_umh_cltrack_upcall(char *cmd, char *arg, char *env0, char *env1)
1188{
1189	char *envp[3];
1190	char *argv[4];
1191	int ret;
1192
1193	if (unlikely(!cltrack_prog[0])) {
1194		dprintk("%s: cltrack_prog is disabled\n", __func__);
1195		return -EACCES;
1196	}
1197
1198	dprintk("%s: cmd: %s\n", __func__, cmd);
1199	dprintk("%s: arg: %s\n", __func__, arg ? arg : "(null)");
1200	dprintk("%s: env0: %s\n", __func__, env0 ? env0 : "(null)");
1201	dprintk("%s: env1: %s\n", __func__, env1 ? env1 : "(null)");
1202
1203	envp[0] = env0;
1204	envp[1] = env1;
1205	envp[2] = NULL;
1206
1207	argv[0] = (char *)cltrack_prog;
1208	argv[1] = cmd;
1209	argv[2] = arg;
1210	argv[3] = NULL;
1211
1212	ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
1213	/*
1214	 * Disable the upcall mechanism if we're getting an ENOENT or EACCES
1215	 * error. The admin can re-enable it on the fly by using sysfs
1216	 * once the problem has been fixed.
1217	 */
1218	if (ret == -ENOENT || ret == -EACCES) {
1219		dprintk("NFSD: %s was not found or isn't executable (%d). "
1220			"Setting cltrack_prog to blank string!",
1221			cltrack_prog, ret);
1222		cltrack_prog[0] = '\0';
1223	}
1224	dprintk("%s: %s return value: %d\n", __func__, cltrack_prog, ret);
1225
1226	return ret;
1227}
1228
1229static char *
1230bin_to_hex_dup(const unsigned char *src, int srclen)
1231{
1232	int i;
1233	char *buf, *hex;
1234
1235	/* +1 for terminating NULL */
1236	buf = kmalloc((srclen * 2) + 1, GFP_KERNEL);
1237	if (!buf)
1238		return buf;
1239
1240	hex = buf;
1241	for (i = 0; i < srclen; i++) {
1242		sprintf(hex, "%2.2x", *src++);
1243		hex += 2;
1244	}
1245	return buf;
1246}
1247
1248static int
1249nfsd4_umh_cltrack_init(struct net *net)
1250{
1251	int ret;
1252	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
1253	char *grace_start = nfsd4_cltrack_grace_start(nn->boot_time);
1254
1255	/* XXX: The usermode helper s not working in container yet. */
1256	if (net != &init_net) {
1257		WARN(1, KERN_ERR "NFSD: attempt to initialize umh client "
1258			"tracking in a container!\n");
1259		return -EINVAL;
1260	}
1261
1262	ret = nfsd4_umh_cltrack_upcall("init", NULL, grace_start, NULL);
1263	kfree(grace_start);
1264	return ret;
1265}
1266
1267static void
1268nfsd4_cltrack_upcall_lock(struct nfs4_client *clp)
1269{
1270	wait_on_bit_lock(&clp->cl_flags, NFSD4_CLIENT_UPCALL_LOCK,
1271			 TASK_UNINTERRUPTIBLE);
1272}
1273
1274static void
1275nfsd4_cltrack_upcall_unlock(struct nfs4_client *clp)
1276{
1277	smp_mb__before_atomic();
1278	clear_bit(NFSD4_CLIENT_UPCALL_LOCK, &clp->cl_flags);
1279	smp_mb__after_atomic();
1280	wake_up_bit(&clp->cl_flags, NFSD4_CLIENT_UPCALL_LOCK);
1281}
1282
1283static void
1284nfsd4_umh_cltrack_create(struct nfs4_client *clp)
1285{
1286	char *hexid, *has_session, *grace_start;
1287	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
1288
1289	/*
1290	 * With v4.0 clients, there's little difference in outcome between a
1291	 * create and check operation, and we can end up calling into this
1292	 * function multiple times per client (once for each openowner). So,
1293	 * for v4.0 clients skip upcalling once the client has been recorded
1294	 * on stable storage.
1295	 *
1296	 * For v4.1+ clients, the outcome of the two operations is different,
1297	 * so we must ensure that we upcall for the create operation. v4.1+
1298	 * clients call this on RECLAIM_COMPLETE though, so we should only end
1299	 * up doing a single create upcall per client.
1300	 */
1301	if (clp->cl_minorversion == 0 &&
1302	    test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
1303		return;
1304
1305	hexid = bin_to_hex_dup(clp->cl_name.data, clp->cl_name.len);
1306	if (!hexid) {
1307		dprintk("%s: can't allocate memory for upcall!\n", __func__);
1308		return;
1309	}
1310
1311	has_session = nfsd4_cltrack_client_has_session(clp);
1312	grace_start = nfsd4_cltrack_grace_start(nn->boot_time);
1313
1314	nfsd4_cltrack_upcall_lock(clp);
1315	if (!nfsd4_umh_cltrack_upcall("create", hexid, has_session, grace_start))
1316		set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
1317	nfsd4_cltrack_upcall_unlock(clp);
1318
1319	kfree(has_session);
1320	kfree(grace_start);
1321	kfree(hexid);
1322}
1323
1324static void
1325nfsd4_umh_cltrack_remove(struct nfs4_client *clp)
1326{
1327	char *hexid;
1328
1329	if (!test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
1330		return;
1331
1332	hexid = bin_to_hex_dup(clp->cl_name.data, clp->cl_name.len);
1333	if (!hexid) {
1334		dprintk("%s: can't allocate memory for upcall!\n", __func__);
1335		return;
1336	}
1337
1338	nfsd4_cltrack_upcall_lock(clp);
1339	if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags) &&
1340	    nfsd4_umh_cltrack_upcall("remove", hexid, NULL, NULL) == 0)
1341		clear_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
1342	nfsd4_cltrack_upcall_unlock(clp);
1343
1344	kfree(hexid);
1345}
1346
1347static int
1348nfsd4_umh_cltrack_check(struct nfs4_client *clp)
1349{
1350	int ret;
1351	char *hexid, *has_session, *legacy;
1352
1353	if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))
1354		return 0;
1355
1356	hexid = bin_to_hex_dup(clp->cl_name.data, clp->cl_name.len);
1357	if (!hexid) {
1358		dprintk("%s: can't allocate memory for upcall!\n", __func__);
1359		return -ENOMEM;
1360	}
1361
1362	has_session = nfsd4_cltrack_client_has_session(clp);
1363	legacy = nfsd4_cltrack_legacy_recdir(&clp->cl_name);
1364
1365	nfsd4_cltrack_upcall_lock(clp);
1366	if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags)) {
1367		ret = 0;
1368	} else {
1369		ret = nfsd4_umh_cltrack_upcall("check", hexid, has_session, legacy);
1370		if (ret == 0)
1371			set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
1372	}
1373	nfsd4_cltrack_upcall_unlock(clp);
1374	kfree(has_session);
1375	kfree(legacy);
1376	kfree(hexid);
1377
1378	return ret;
1379}
1380
1381static void
1382nfsd4_umh_cltrack_grace_done(struct nfsd_net *nn)
1383{
1384	char *legacy;
1385	char timestr[22]; /* FIXME: better way to determine max size? */
1386
1387	sprintf(timestr, "%ld", nn->boot_time);
1388	legacy = nfsd4_cltrack_legacy_topdir();
1389	nfsd4_umh_cltrack_upcall("gracedone", timestr, legacy, NULL);
1390	kfree(legacy);
1391}
1392
1393static struct nfsd4_client_tracking_ops nfsd4_umh_tracking_ops = {
1394	.init		= nfsd4_umh_cltrack_init,
1395	.exit		= NULL,
1396	.create		= nfsd4_umh_cltrack_create,
1397	.remove		= nfsd4_umh_cltrack_remove,
1398	.check		= nfsd4_umh_cltrack_check,
1399	.grace_done	= nfsd4_umh_cltrack_grace_done,
1400};
1401
1402int
1403nfsd4_client_tracking_init(struct net *net)
1404{
1405	int status;
1406	struct path path;
1407	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
1408
1409	/* just run the init if it the method is already decided */
1410	if (nn->client_tracking_ops)
1411		goto do_init;
1412
1413	/*
1414	 * First, try a UMH upcall. It should succeed or fail quickly, so
1415	 * there's little harm in trying that first.
1416	 */
1417	nn->client_tracking_ops = &nfsd4_umh_tracking_ops;
1418	status = nn->client_tracking_ops->init(net);
1419	if (!status)
1420		return status;
1421
1422	/*
1423	 * See if the recoverydir exists and is a directory. If it is,
1424	 * then use the legacy ops.
1425	 */
1426	nn->client_tracking_ops = &nfsd4_legacy_tracking_ops;
1427	status = kern_path(nfs4_recoverydir(), LOOKUP_FOLLOW, &path);
1428	if (!status) {
1429		status = d_is_dir(path.dentry);
1430		path_put(&path);
1431		if (status)
1432			goto do_init;
1433	}
1434
1435	/* Finally, try to use nfsdcld */
1436	nn->client_tracking_ops = &nfsd4_cld_tracking_ops;
1437	printk(KERN_WARNING "NFSD: the nfsdcld client tracking upcall will be "
1438			"removed in 3.10. Please transition to using "
1439			"nfsdcltrack.\n");
1440do_init:
1441	status = nn->client_tracking_ops->init(net);
1442	if (status) {
1443		printk(KERN_WARNING "NFSD: Unable to initialize client "
1444				    "recovery tracking! (%d)\n", status);
1445		nn->client_tracking_ops = NULL;
1446	}
1447	return status;
1448}
1449
1450void
1451nfsd4_client_tracking_exit(struct net *net)
1452{
1453	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
1454
1455	if (nn->client_tracking_ops) {
1456		if (nn->client_tracking_ops->exit)
1457			nn->client_tracking_ops->exit(net);
1458		nn->client_tracking_ops = NULL;
1459	}
1460}
1461
1462void
1463nfsd4_client_record_create(struct nfs4_client *clp)
1464{
1465	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
1466
1467	if (nn->client_tracking_ops)
1468		nn->client_tracking_ops->create(clp);
1469}
1470
1471void
1472nfsd4_client_record_remove(struct nfs4_client *clp)
1473{
1474	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
1475
1476	if (nn->client_tracking_ops)
1477		nn->client_tracking_ops->remove(clp);
1478}
1479
1480int
1481nfsd4_client_record_check(struct nfs4_client *clp)
1482{
1483	struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
1484
1485	if (nn->client_tracking_ops)
1486		return nn->client_tracking_ops->check(clp);
1487
1488	return -EOPNOTSUPP;
1489}
1490
1491void
1492nfsd4_record_grace_done(struct nfsd_net *nn)
1493{
1494	if (nn->client_tracking_ops)
1495		nn->client_tracking_ops->grace_done(nn);
1496}
1497
1498static int
1499rpc_pipefs_event(struct notifier_block *nb, unsigned long event, void *ptr)
1500{
1501	struct super_block *sb = ptr;
1502	struct net *net = sb->s_fs_info;
1503	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
1504	struct cld_net *cn = nn->cld_net;
1505	struct dentry *dentry;
1506	int ret = 0;
1507
1508	if (!try_module_get(THIS_MODULE))
1509		return 0;
1510
1511	if (!cn) {
1512		module_put(THIS_MODULE);
1513		return 0;
1514	}
1515
1516	switch (event) {
1517	case RPC_PIPEFS_MOUNT:
1518		dentry = nfsd4_cld_register_sb(sb, cn->cn_pipe);
1519		if (IS_ERR(dentry)) {
1520			ret = PTR_ERR(dentry);
1521			break;
1522		}
1523		cn->cn_pipe->dentry = dentry;
1524		break;
1525	case RPC_PIPEFS_UMOUNT:
1526		if (cn->cn_pipe->dentry)
1527			nfsd4_cld_unregister_sb(cn->cn_pipe);
1528		break;
1529	default:
1530		ret = -ENOTSUPP;
1531		break;
1532	}
1533	module_put(THIS_MODULE);
1534	return ret;
1535}
1536
1537static struct notifier_block nfsd4_cld_block = {
1538	.notifier_call = rpc_pipefs_event,
1539};
1540
1541int
1542register_cld_notifier(void)
1543{
1544	return rpc_pipefs_notifier_register(&nfsd4_cld_block);
1545}
1546
1547void
1548unregister_cld_notifier(void)
1549{
1550	rpc_pipefs_notifier_unregister(&nfsd4_cld_block);
1551}
1552