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/slab.h>
14#include <linux/mutex.h>
15#include <linux/sunrpc/svc.h>
16#include <linux/sunrpc/clnt.h>
17#include <linux/nfsd/nfsfh.h>
18#include <linux/nfsd/export.h>
19#include <linux/lockd/lockd.h>
20#include <linux/lockd/share.h>
21#include <linux/module.h>
22#include <linux/mount.h>
23
24#define NLMDBG_FACILITY		NLMDBG_SVCSUBS
25
26
27/*
28 * Global file hash table
29 */
30#define FILE_HASH_BITS		7
31#define FILE_NRHASH		(1<<FILE_HASH_BITS)
32static struct hlist_head	nlm_files[FILE_NRHASH];
33static DEFINE_MUTEX(nlm_file_mutex);
34
35#ifdef NFSD_DEBUG
36static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
37{
38	u32 *fhp = (u32*)f->data;
39
40	/* print the first 32 bytes of the fh */
41	dprintk("lockd: %s (%08x %08x %08x %08x %08x %08x %08x %08x)\n",
42		msg, fhp[0], fhp[1], fhp[2], fhp[3],
43		fhp[4], fhp[5], fhp[6], fhp[7]);
44}
45
46static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
47{
48	struct inode *inode = file->f_file->f_path.dentry->d_inode;
49
50	dprintk("lockd: %s %s/%ld\n",
51		msg, inode->i_sb->s_id, inode->i_ino);
52}
53#else
54static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
55{
56	return;
57}
58
59static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
60{
61	return;
62}
63#endif
64
65static inline unsigned int file_hash(struct nfs_fh *f)
66{
67	unsigned int tmp=0;
68	int i;
69	for (i=0; i<NFS2_FHSIZE;i++)
70		tmp += f->data[i];
71	return tmp & (FILE_NRHASH - 1);
72}
73
74__be32
75nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
76					struct nfs_fh *f)
77{
78	struct hlist_node *pos;
79	struct nlm_file	*file;
80	unsigned int	hash;
81	__be32		nfserr;
82
83	nlm_debug_print_fh("nlm_lookup_file", f);
84
85	hash = file_hash(f);
86
87	/* Lock file table */
88	mutex_lock(&nlm_file_mutex);
89
90	hlist_for_each_entry(file, pos, &nlm_files[hash], f_list)
91		if (!nfs_compare_fh(&file->f_handle, f))
92			goto found;
93
94	nlm_debug_print_fh("creating file for", f);
95
96	nfserr = nlm_lck_denied_nolocks;
97	file = kzalloc(sizeof(*file), GFP_KERNEL);
98	if (!file)
99		goto out_unlock;
100
101	memcpy(&file->f_handle, f, sizeof(struct nfs_fh));
102	mutex_init(&file->f_mutex);
103	INIT_HLIST_NODE(&file->f_list);
104	INIT_LIST_HEAD(&file->f_blocks);
105
106	/* Open the file. Note that this must not sleep for too long, else
107	 * we would lock up lockd:-) So no NFS re-exports, folks.
108	 *
109	 * We have to make sure we have the right credential to open
110	 * the file.
111	 */
112	if ((nfserr = nlmsvc_ops->fopen(rqstp, f, &file->f_file)) != 0) {
113		dprintk("lockd: open failed (error %d)\n", nfserr);
114		goto out_free;
115	}
116
117	hlist_add_head(&file->f_list, &nlm_files[hash]);
118
119found:
120	dprintk("lockd: found file %p (count %d)\n", file, file->f_count);
121	*result = file;
122	file->f_count++;
123	nfserr = 0;
124
125out_unlock:
126	mutex_unlock(&nlm_file_mutex);
127	return nfserr;
128
129out_free:
130	kfree(file);
131	goto out_unlock;
132}
133
134/*
135 * Delete a file after having released all locks, blocks and shares
136 */
137static inline void
138nlm_delete_file(struct nlm_file *file)
139{
140	nlm_debug_print_file("closing file", file);
141	if (!hlist_unhashed(&file->f_list)) {
142		hlist_del(&file->f_list);
143		nlmsvc_ops->fclose(file->f_file);
144		kfree(file);
145	} else {
146		printk(KERN_WARNING "lockd: attempt to release unknown file!\n");
147	}
148}
149
150/*
151 * Loop over all locks on the given file and perform the specified
152 * action.
153 */
154static int
155nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file,
156			nlm_host_match_fn_t match)
157{
158	struct inode	 *inode = nlmsvc_file_inode(file);
159	struct file_lock *fl;
160	struct nlm_host	 *lockhost;
161
162again:
163	file->f_locks = 0;
164	for (fl = inode->i_flock; fl; fl = fl->fl_next) {
165		if (fl->fl_lmops != &nlmsvc_lock_operations)
166			continue;
167
168		/* update current lock count */
169		file->f_locks++;
170
171		lockhost = (struct nlm_host *) fl->fl_owner;
172		if (match(lockhost, host)) {
173			struct file_lock lock = *fl;
174
175			lock.fl_type  = F_UNLCK;
176			lock.fl_start = 0;
177			lock.fl_end   = OFFSET_MAX;
178			if (vfs_lock_file(file->f_file, F_SETLK, &lock, NULL) < 0) {
179				printk("lockd: unlock failure in %s:%d\n",
180						__FILE__, __LINE__);
181				return 1;
182			}
183			goto again;
184		}
185	}
186
187	return 0;
188}
189
190static int
191nlmsvc_always_match(void *dummy1, struct nlm_host *dummy2)
192{
193	return 1;
194}
195
196/*
197 * Inspect a single file
198 */
199static inline int
200nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, nlm_host_match_fn_t match)
201{
202	nlmsvc_traverse_blocks(host, file, match);
203	nlmsvc_traverse_shares(host, file, match);
204	return nlm_traverse_locks(host, file, match);
205}
206
207/*
208 * Quick check whether there are still any locks, blocks or
209 * shares on a given file.
210 */
211static inline int
212nlm_file_inuse(struct nlm_file *file)
213{
214	struct inode	 *inode = nlmsvc_file_inode(file);
215	struct file_lock *fl;
216
217	if (file->f_count || !list_empty(&file->f_blocks) || file->f_shares)
218		return 1;
219
220	for (fl = inode->i_flock; fl; fl = fl->fl_next) {
221		if (fl->fl_lmops == &nlmsvc_lock_operations)
222			return 1;
223	}
224	file->f_locks = 0;
225	return 0;
226}
227
228/*
229 * Loop over all files in the file table.
230 */
231static int
232nlm_traverse_files(void *data, nlm_host_match_fn_t match,
233		int (*is_failover_file)(void *data, struct nlm_file *file))
234{
235	struct hlist_node *pos, *next;
236	struct nlm_file	*file;
237	int i, ret = 0;
238
239	mutex_lock(&nlm_file_mutex);
240	for (i = 0; i < FILE_NRHASH; i++) {
241		hlist_for_each_entry_safe(file, pos, next, &nlm_files[i], f_list) {
242			if (is_failover_file && !is_failover_file(data, file))
243				continue;
244			file->f_count++;
245			mutex_unlock(&nlm_file_mutex);
246
247			/* Traverse locks, blocks and shares of this file
248			 * and update file->f_locks count */
249			if (nlm_inspect_file(data, file, match))
250				ret = 1;
251
252			mutex_lock(&nlm_file_mutex);
253			file->f_count--;
254			/* No more references to this file. Let go of it. */
255			if (list_empty(&file->f_blocks) && !file->f_locks
256			 && !file->f_shares && !file->f_count) {
257				hlist_del(&file->f_list);
258				nlmsvc_ops->fclose(file->f_file);
259				kfree(file);
260			}
261		}
262	}
263	mutex_unlock(&nlm_file_mutex);
264	return ret;
265}
266
267/*
268 * Release file. If there are no more remote locks on this file,
269 * close it and free the handle.
270 *
271 * Note that we can't do proper reference counting without major
272 * contortions because the code in fs/locks.c creates, deletes and
273 * splits locks without notification. Our only way is to walk the
274 * entire lock list each time we remove a lock.
275 */
276void
277nlm_release_file(struct nlm_file *file)
278{
279	dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
280				file, file->f_count);
281
282	/* Lock file table */
283	mutex_lock(&nlm_file_mutex);
284
285	/* If there are no more locks etc, delete the file */
286	if (--file->f_count == 0 && !nlm_file_inuse(file))
287		nlm_delete_file(file);
288
289	mutex_unlock(&nlm_file_mutex);
290}
291
292/*
293 * Helpers function for resource traversal
294 *
295 * nlmsvc_mark_host:
296 *	used by the garbage collector; simply sets h_inuse.
297 *	Always returns 0.
298 *
299 * nlmsvc_same_host:
300 *	returns 1 iff the two hosts match. Used to release
301 *	all resources bound to a specific host.
302 *
303 * nlmsvc_is_client:
304 *	returns 1 iff the host is a client.
305 *	Used by nlmsvc_invalidate_all
306 */
307static int
308nlmsvc_mark_host(void *data, struct nlm_host *dummy)
309{
310	struct nlm_host *host = data;
311
312	host->h_inuse = 1;
313	return 0;
314}
315
316static int
317nlmsvc_same_host(void *data, struct nlm_host *other)
318{
319	struct nlm_host *host = data;
320
321	return host == other;
322}
323
324static int
325nlmsvc_is_client(void *data, struct nlm_host *dummy)
326{
327	struct nlm_host *host = data;
328
329	if (host->h_server) {
330		/* we are destroying locks even though the client
331		 * hasn't asked us too, so don't unmonitor the
332		 * client
333		 */
334		if (host->h_nsmhandle)
335			host->h_nsmhandle->sm_sticky = 1;
336		return 1;
337	} else
338		return 0;
339}
340
341/*
342 * Mark all hosts that still hold resources
343 */
344void
345nlmsvc_mark_resources(void)
346{
347	dprintk("lockd: nlmsvc_mark_resources\n");
348	nlm_traverse_files(NULL, nlmsvc_mark_host, NULL);
349}
350
351/*
352 * Release all resources held by the given client
353 */
354void
355nlmsvc_free_host_resources(struct nlm_host *host)
356{
357	dprintk("lockd: nlmsvc_free_host_resources\n");
358
359	if (nlm_traverse_files(host, nlmsvc_same_host, NULL)) {
360		printk(KERN_WARNING
361			"lockd: couldn't remove all locks held by %s\n",
362			host->h_name);
363		BUG();
364	}
365}
366
367/**
368 * nlmsvc_invalidate_all - remove all locks held for clients
369 *
370 * Release all locks held by NFS clients.
371 *
372 */
373void
374nlmsvc_invalidate_all(void)
375{
376	/*
377	 * Previously, the code would call
378	 * nlmsvc_free_host_resources for each client in
379	 * turn, which is about as inefficient as it gets.
380	 * Now we just do it once in nlm_traverse_files.
381	 */
382	nlm_traverse_files(NULL, nlmsvc_is_client, NULL);
383}
384
385static int
386nlmsvc_match_sb(void *datap, struct nlm_file *file)
387{
388	struct super_block *sb = datap;
389
390	return sb == file->f_file->f_path.mnt->mnt_sb;
391}
392
393/**
394 * nlmsvc_unlock_all_by_sb - release locks held on this file system
395 * @sb: super block
396 *
397 * Release all locks held by clients accessing this file system.
398 */
399int
400nlmsvc_unlock_all_by_sb(struct super_block *sb)
401{
402	int ret;
403
404	ret = nlm_traverse_files(sb, nlmsvc_always_match, nlmsvc_match_sb);
405	return ret ? -EIO : 0;
406}
407EXPORT_SYMBOL_GPL(nlmsvc_unlock_all_by_sb);
408
409static int
410nlmsvc_match_ip(void *datap, struct nlm_host *host)
411{
412	return rpc_cmp_addr(nlm_srcaddr(host), datap);
413}
414
415/**
416 * nlmsvc_unlock_all_by_ip - release local locks by IP address
417 * @server_addr: server's IP address as seen by clients
418 *
419 * Release all locks held by clients accessing this host
420 * via the passed in IP address.
421 */
422int
423nlmsvc_unlock_all_by_ip(struct sockaddr *server_addr)
424{
425	int ret;
426
427	ret = nlm_traverse_files(server_addr, nlmsvc_match_ip, NULL);
428	return ret ? -EIO : 0;
429}
430EXPORT_SYMBOL_GPL(nlmsvc_unlock_all_by_ip);
431