1/*
2 * linux/fs/lockd/svcsubs.c
3 *
4 * Various support routines for the NLM server.
5 *
6 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
7 */
8
9#include <linux/types.h>
10#include <linux/string.h>
11#include <linux/time.h>
12#include <linux/in.h>
13#include <linux/mutex.h>
14#include <linux/sunrpc/svc.h>
15#include <linux/sunrpc/clnt.h>
16#include <linux/nfsd/nfsfh.h>
17#include <linux/nfsd/export.h>
18#include <linux/lockd/lockd.h>
19#include <linux/lockd/share.h>
20#include <linux/lockd/sm_inter.h>
21
22#define NLMDBG_FACILITY		NLMDBG_SVCSUBS
23
24
25/*
26 * Global file hash table
27 */
28#define FILE_HASH_BITS		7
29#define FILE_NRHASH		(1<<FILE_HASH_BITS)
30static struct hlist_head	nlm_files[FILE_NRHASH];
31static DEFINE_MUTEX(nlm_file_mutex);
32
33#ifdef NFSD_DEBUG
34static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
35{
36	u32 *fhp = (u32*)f->data;
37
38	/* print the first 32 bytes of the fh */
39	dprintk("lockd: %s (%08x %08x %08x %08x %08x %08x %08x %08x)\n",
40		msg, fhp[0], fhp[1], fhp[2], fhp[3],
41		fhp[4], fhp[5], fhp[6], fhp[7]);
42}
43
44static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
45{
46	struct inode *inode = file->f_file->f_path.dentry->d_inode;
47
48	dprintk("lockd: %s %s/%ld\n",
49		msg, inode->i_sb->s_id, inode->i_ino);
50}
51#else
52static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
53{
54	return;
55}
56
57static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
58{
59	return;
60}
61#endif
62
63static inline unsigned int file_hash(struct nfs_fh *f)
64{
65	unsigned int tmp=0;
66	int i;
67	for (i=0; i<NFS2_FHSIZE;i++)
68		tmp += f->data[i];
69	return tmp & (FILE_NRHASH - 1);
70}
71
72__be32
73nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
74					struct nfs_fh *f)
75{
76	struct hlist_node *pos;
77	struct nlm_file	*file;
78	unsigned int	hash;
79	__be32		nfserr;
80
81	nlm_debug_print_fh("nlm_file_lookup", f);
82
83	hash = file_hash(f);
84
85	/* Lock file table */
86	mutex_lock(&nlm_file_mutex);
87
88	hlist_for_each_entry(file, pos, &nlm_files[hash], f_list)
89		if (!nfs_compare_fh(&file->f_handle, f))
90			goto found;
91
92	nlm_debug_print_fh("creating file for", f);
93
94	nfserr = nlm_lck_denied_nolocks;
95	file = kzalloc(sizeof(*file), GFP_KERNEL);
96	if (!file)
97		goto out_unlock;
98
99	memcpy(&file->f_handle, f, sizeof(struct nfs_fh));
100	mutex_init(&file->f_mutex);
101	INIT_HLIST_NODE(&file->f_list);
102	INIT_LIST_HEAD(&file->f_blocks);
103
104	/* Open the file. Note that this must not sleep for too long, else
105	 * we would lock up lockd:-) So no NFS re-exports, folks.
106	 *
107	 * We have to make sure we have the right credential to open
108	 * the file.
109	 */
110	if ((nfserr = nlmsvc_ops->fopen(rqstp, f, &file->f_file)) != 0) {
111		dprintk("lockd: open failed (error %d)\n", nfserr);
112		goto out_free;
113	}
114
115	hlist_add_head(&file->f_list, &nlm_files[hash]);
116
117found:
118	dprintk("lockd: found file %p (count %d)\n", file, file->f_count);
119	*result = file;
120	file->f_count++;
121	nfserr = 0;
122
123out_unlock:
124	mutex_unlock(&nlm_file_mutex);
125	return nfserr;
126
127out_free:
128	kfree(file);
129	goto out_unlock;
130}
131
132/*
133 * Delete a file after having released all locks, blocks and shares
134 */
135static inline void
136nlm_delete_file(struct nlm_file *file)
137{
138	nlm_debug_print_file("closing file", file);
139	if (!hlist_unhashed(&file->f_list)) {
140		hlist_del(&file->f_list);
141		nlmsvc_ops->fclose(file->f_file);
142		kfree(file);
143	} else {
144		printk(KERN_WARNING "lockd: attempt to release unknown file!\n");
145	}
146}
147
148/*
149 * Loop over all locks on the given file and perform the specified
150 * action.
151 */
152static int
153nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file,
154			nlm_host_match_fn_t match)
155{
156	struct inode	 *inode = nlmsvc_file_inode(file);
157	struct file_lock *fl;
158	struct nlm_host	 *lockhost;
159
160again:
161	file->f_locks = 0;
162	for (fl = inode->i_flock; fl; fl = fl->fl_next) {
163		if (fl->fl_lmops != &nlmsvc_lock_operations)
164			continue;
165
166		/* update current lock count */
167		file->f_locks++;
168
169		lockhost = (struct nlm_host *) fl->fl_owner;
170		if (match(lockhost, host)) {
171			struct file_lock lock = *fl;
172
173			lock.fl_type  = F_UNLCK;
174			lock.fl_start = 0;
175			lock.fl_end   = OFFSET_MAX;
176			if (vfs_lock_file(file->f_file, F_SETLK, &lock, NULL) < 0) {
177				printk("lockd: unlock failure in %s:%d\n",
178						__FILE__, __LINE__);
179				return 1;
180			}
181			goto again;
182		}
183	}
184
185	return 0;
186}
187
188/*
189 * Inspect a single file
190 */
191static inline int
192nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, nlm_host_match_fn_t match)
193{
194	nlmsvc_traverse_blocks(host, file, match);
195	nlmsvc_traverse_shares(host, file, match);
196	return nlm_traverse_locks(host, file, match);
197}
198
199/*
200 * Quick check whether there are still any locks, blocks or
201 * shares on a given file.
202 */
203static inline int
204nlm_file_inuse(struct nlm_file *file)
205{
206	struct inode	 *inode = nlmsvc_file_inode(file);
207	struct file_lock *fl;
208
209	if (file->f_count || !list_empty(&file->f_blocks) || file->f_shares)
210		return 1;
211
212	for (fl = inode->i_flock; fl; fl = fl->fl_next) {
213		if (fl->fl_lmops == &nlmsvc_lock_operations)
214			return 1;
215	}
216	file->f_locks = 0;
217	return 0;
218}
219
220/*
221 * Loop over all files in the file table.
222 */
223static int
224nlm_traverse_files(struct nlm_host *host, nlm_host_match_fn_t match)
225{
226	struct hlist_node *pos, *next;
227	struct nlm_file	*file;
228	int i, ret = 0;
229
230	mutex_lock(&nlm_file_mutex);
231	for (i = 0; i < FILE_NRHASH; i++) {
232		hlist_for_each_entry_safe(file, pos, next, &nlm_files[i], f_list) {
233			file->f_count++;
234			mutex_unlock(&nlm_file_mutex);
235
236			/* Traverse locks, blocks and shares of this file
237			 * and update file->f_locks count */
238			if (nlm_inspect_file(host, file, match))
239				ret = 1;
240
241			mutex_lock(&nlm_file_mutex);
242			file->f_count--;
243			/* No more references to this file. Let go of it. */
244			if (list_empty(&file->f_blocks) && !file->f_locks
245			 && !file->f_shares && !file->f_count) {
246				hlist_del(&file->f_list);
247				nlmsvc_ops->fclose(file->f_file);
248				kfree(file);
249			}
250		}
251	}
252	mutex_unlock(&nlm_file_mutex);
253	return ret;
254}
255
256/*
257 * Release file. If there are no more remote locks on this file,
258 * close it and free the handle.
259 *
260 * Note that we can't do proper reference counting without major
261 * contortions because the code in fs/locks.c creates, deletes and
262 * splits locks without notification. Our only way is to walk the
263 * entire lock list each time we remove a lock.
264 */
265void
266nlm_release_file(struct nlm_file *file)
267{
268	dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
269				file, file->f_count);
270
271	/* Lock file table */
272	mutex_lock(&nlm_file_mutex);
273
274	/* If there are no more locks etc, delete the file */
275	if (--file->f_count == 0 && !nlm_file_inuse(file))
276		nlm_delete_file(file);
277
278	mutex_unlock(&nlm_file_mutex);
279}
280
281/*
282 * Helpers function for resource traversal
283 *
284 * nlmsvc_mark_host:
285 *	used by the garbage collector; simply sets h_inuse.
286 *	Always returns 0.
287 *
288 * nlmsvc_same_host:
289 *	returns 1 iff the two hosts match. Used to release
290 *	all resources bound to a specific host.
291 *
292 * nlmsvc_is_client:
293 *	returns 1 iff the host is a client.
294 *	Used by nlmsvc_invalidate_all
295 */
296static int
297nlmsvc_mark_host(struct nlm_host *host, struct nlm_host *dummy)
298{
299	host->h_inuse = 1;
300	return 0;
301}
302
303static int
304nlmsvc_same_host(struct nlm_host *host, struct nlm_host *other)
305{
306	return host == other;
307}
308
309static int
310nlmsvc_is_client(struct nlm_host *host, struct nlm_host *dummy)
311{
312	if (host->h_server) {
313		/* we are destroying locks even though the client
314		 * hasn't asked us too, so don't unmonitor the
315		 * client
316		 */
317		if (host->h_nsmhandle)
318			host->h_nsmhandle->sm_sticky = 1;
319		return 1;
320	} else
321		return 0;
322}
323
324/*
325 * Mark all hosts that still hold resources
326 */
327void
328nlmsvc_mark_resources(void)
329{
330	dprintk("lockd: nlmsvc_mark_resources\n");
331	nlm_traverse_files(NULL, nlmsvc_mark_host);
332}
333
334/*
335 * Release all resources held by the given client
336 */
337void
338nlmsvc_free_host_resources(struct nlm_host *host)
339{
340	dprintk("lockd: nlmsvc_free_host_resources\n");
341
342	if (nlm_traverse_files(host, nlmsvc_same_host)) {
343		printk(KERN_WARNING
344			"lockd: couldn't remove all locks held by %s\n",
345			host->h_name);
346		BUG();
347	}
348}
349
350/*
351 * Remove all locks held for clients
352 */
353void
354nlmsvc_invalidate_all(void)
355{
356	/* Release all locks held by NFS clients.
357	 * Previously, the code would call
358	 * nlmsvc_free_host_resources for each client in
359	 * turn, which is about as inefficient as it gets.
360	 * Now we just do it once in nlm_traverse_files.
361	 */
362	nlm_traverse_files(NULL, nlmsvc_is_client);
363}
364