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/addr.h>
17 #include <linux/lockd/lockd.h>
18 #include <linux/lockd/share.h>
19 #include <linux/module.h>
20 #include <linux/mount.h>
21 #include <uapi/linux/nfs2.h>
22 
23 #define NLMDBG_FACILITY		NLMDBG_SVCSUBS
24 
25 
26 /*
27  * Global file hash table
28  */
29 #define FILE_HASH_BITS		7
30 #define FILE_NRHASH		(1<<FILE_HASH_BITS)
31 static struct hlist_head	nlm_files[FILE_NRHASH];
32 static DEFINE_MUTEX(nlm_file_mutex);
33 
34 #ifdef CONFIG_SUNRPC_DEBUG
nlm_debug_print_fh(char * msg,struct nfs_fh * f)35 static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
36 {
37 	u32 *fhp = (u32*)f->data;
38 
39 	/* print the first 32 bytes of the fh */
40 	dprintk("lockd: %s (%08x %08x %08x %08x %08x %08x %08x %08x)\n",
41 		msg, fhp[0], fhp[1], fhp[2], fhp[3],
42 		fhp[4], fhp[5], fhp[6], fhp[7]);
43 }
44 
nlm_debug_print_file(char * msg,struct nlm_file * file)45 static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
46 {
47 	struct inode *inode = locks_inode(file->f_file);
48 
49 	dprintk("lockd: %s %s/%ld\n",
50 		msg, inode->i_sb->s_id, inode->i_ino);
51 }
52 #else
nlm_debug_print_fh(char * msg,struct nfs_fh * f)53 static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
54 {
55 	return;
56 }
57 
nlm_debug_print_file(char * msg,struct nlm_file * file)58 static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
59 {
60 	return;
61 }
62 #endif
63 
file_hash(struct nfs_fh * f)64 static inline unsigned int file_hash(struct nfs_fh *f)
65 {
66 	unsigned int tmp=0;
67 	int i;
68 	for (i=0; i<NFS2_FHSIZE;i++)
69 		tmp += f->data[i];
70 	return tmp & (FILE_NRHASH - 1);
71 }
72 
73 /*
74  * Lookup file info. If it doesn't exist, create a file info struct
75  * and open a (VFS) file for the given inode.
76  *
77  * FIXME:
78  * Note that we open the file O_RDONLY even when creating write locks.
79  * This is not quite right, but for now, we assume the client performs
80  * the proper R/W checking.
81  */
82 __be32
nlm_lookup_file(struct svc_rqst * rqstp,struct nlm_file ** result,struct nfs_fh * f)83 nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
84 					struct nfs_fh *f)
85 {
86 	struct nlm_file	*file;
87 	unsigned int	hash;
88 	__be32		nfserr;
89 
90 	nlm_debug_print_fh("nlm_lookup_file", f);
91 
92 	hash = file_hash(f);
93 
94 	/* Lock file table */
95 	mutex_lock(&nlm_file_mutex);
96 
97 	hlist_for_each_entry(file, &nlm_files[hash], f_list)
98 		if (!nfs_compare_fh(&file->f_handle, f))
99 			goto found;
100 
101 	nlm_debug_print_fh("creating file for", f);
102 
103 	nfserr = nlm_lck_denied_nolocks;
104 	file = kzalloc(sizeof(*file), GFP_KERNEL);
105 	if (!file)
106 		goto out_unlock;
107 
108 	memcpy(&file->f_handle, f, sizeof(struct nfs_fh));
109 	mutex_init(&file->f_mutex);
110 	INIT_HLIST_NODE(&file->f_list);
111 	INIT_LIST_HEAD(&file->f_blocks);
112 
113 	/* Open the file. Note that this must not sleep for too long, else
114 	 * we would lock up lockd:-) So no NFS re-exports, folks.
115 	 *
116 	 * We have to make sure we have the right credential to open
117 	 * the file.
118 	 */
119 	if ((nfserr = nlmsvc_ops->fopen(rqstp, f, &file->f_file)) != 0) {
120 		dprintk("lockd: open failed (error %d)\n", nfserr);
121 		goto out_free;
122 	}
123 
124 	hlist_add_head(&file->f_list, &nlm_files[hash]);
125 
126 found:
127 	dprintk("lockd: found file %p (count %d)\n", file, file->f_count);
128 	*result = file;
129 	file->f_count++;
130 	nfserr = 0;
131 
132 out_unlock:
133 	mutex_unlock(&nlm_file_mutex);
134 	return nfserr;
135 
136 out_free:
137 	kfree(file);
138 	goto out_unlock;
139 }
140 
141 /*
142  * Delete a file after having released all locks, blocks and shares
143  */
144 static inline void
nlm_delete_file(struct nlm_file * file)145 nlm_delete_file(struct nlm_file *file)
146 {
147 	nlm_debug_print_file("closing file", file);
148 	if (!hlist_unhashed(&file->f_list)) {
149 		hlist_del(&file->f_list);
150 		nlmsvc_ops->fclose(file->f_file);
151 		kfree(file);
152 	} else {
153 		printk(KERN_WARNING "lockd: attempt to release unknown file!\n");
154 	}
155 }
156 
157 /*
158  * Loop over all locks on the given file and perform the specified
159  * action.
160  */
161 static int
nlm_traverse_locks(struct nlm_host * host,struct nlm_file * file,nlm_host_match_fn_t match)162 nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file,
163 			nlm_host_match_fn_t match)
164 {
165 	struct inode	 *inode = nlmsvc_file_inode(file);
166 	struct file_lock *fl;
167 	struct file_lock_context *flctx = inode->i_flctx;
168 	struct nlm_host	 *lockhost;
169 
170 	if (!flctx || list_empty_careful(&flctx->flc_posix))
171 		return 0;
172 again:
173 	file->f_locks = 0;
174 	spin_lock(&flctx->flc_lock);
175 	list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
176 		if (fl->fl_lmops != &nlmsvc_lock_operations)
177 			continue;
178 
179 		/* update current lock count */
180 		file->f_locks++;
181 
182 		lockhost = (struct nlm_host *) fl->fl_owner;
183 		if (match(lockhost, host)) {
184 			struct file_lock lock = *fl;
185 
186 			spin_unlock(&flctx->flc_lock);
187 			lock.fl_type  = F_UNLCK;
188 			lock.fl_start = 0;
189 			lock.fl_end   = OFFSET_MAX;
190 			if (vfs_lock_file(file->f_file, F_SETLK, &lock, NULL) < 0) {
191 				printk("lockd: unlock failure in %s:%d\n",
192 						__FILE__, __LINE__);
193 				return 1;
194 			}
195 			goto again;
196 		}
197 	}
198 	spin_unlock(&flctx->flc_lock);
199 
200 	return 0;
201 }
202 
203 static int
nlmsvc_always_match(void * dummy1,struct nlm_host * dummy2)204 nlmsvc_always_match(void *dummy1, struct nlm_host *dummy2)
205 {
206 	return 1;
207 }
208 
209 /*
210  * Inspect a single file
211  */
212 static inline int
nlm_inspect_file(struct nlm_host * host,struct nlm_file * file,nlm_host_match_fn_t match)213 nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, nlm_host_match_fn_t match)
214 {
215 	nlmsvc_traverse_blocks(host, file, match);
216 	nlmsvc_traverse_shares(host, file, match);
217 	return nlm_traverse_locks(host, file, match);
218 }
219 
220 /*
221  * Quick check whether there are still any locks, blocks or
222  * shares on a given file.
223  */
224 static inline int
nlm_file_inuse(struct nlm_file * file)225 nlm_file_inuse(struct nlm_file *file)
226 {
227 	struct inode	 *inode = nlmsvc_file_inode(file);
228 	struct file_lock *fl;
229 	struct file_lock_context *flctx = inode->i_flctx;
230 
231 	if (file->f_count || !list_empty(&file->f_blocks) || file->f_shares)
232 		return 1;
233 
234 	if (flctx && !list_empty_careful(&flctx->flc_posix)) {
235 		spin_lock(&flctx->flc_lock);
236 		list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
237 			if (fl->fl_lmops == &nlmsvc_lock_operations) {
238 				spin_unlock(&flctx->flc_lock);
239 				return 1;
240 			}
241 		}
242 		spin_unlock(&flctx->flc_lock);
243 	}
244 	file->f_locks = 0;
245 	return 0;
246 }
247 
248 /*
249  * Loop over all files in the file table.
250  */
251 static int
nlm_traverse_files(void * data,nlm_host_match_fn_t match,int (* is_failover_file)(void * data,struct nlm_file * file))252 nlm_traverse_files(void *data, nlm_host_match_fn_t match,
253 		int (*is_failover_file)(void *data, struct nlm_file *file))
254 {
255 	struct hlist_node *next;
256 	struct nlm_file	*file;
257 	int i, ret = 0;
258 
259 	mutex_lock(&nlm_file_mutex);
260 	for (i = 0; i < FILE_NRHASH; i++) {
261 		hlist_for_each_entry_safe(file, next, &nlm_files[i], f_list) {
262 			if (is_failover_file && !is_failover_file(data, file))
263 				continue;
264 			file->f_count++;
265 			mutex_unlock(&nlm_file_mutex);
266 
267 			/* Traverse locks, blocks and shares of this file
268 			 * and update file->f_locks count */
269 			if (nlm_inspect_file(data, file, match))
270 				ret = 1;
271 
272 			mutex_lock(&nlm_file_mutex);
273 			file->f_count--;
274 			/* No more references to this file. Let go of it. */
275 			if (list_empty(&file->f_blocks) && !file->f_locks
276 			 && !file->f_shares && !file->f_count) {
277 				hlist_del(&file->f_list);
278 				nlmsvc_ops->fclose(file->f_file);
279 				kfree(file);
280 			}
281 		}
282 	}
283 	mutex_unlock(&nlm_file_mutex);
284 	return ret;
285 }
286 
287 /*
288  * Release file. If there are no more remote locks on this file,
289  * close it and free the handle.
290  *
291  * Note that we can't do proper reference counting without major
292  * contortions because the code in fs/locks.c creates, deletes and
293  * splits locks without notification. Our only way is to walk the
294  * entire lock list each time we remove a lock.
295  */
296 void
nlm_release_file(struct nlm_file * file)297 nlm_release_file(struct nlm_file *file)
298 {
299 	dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
300 				file, file->f_count);
301 
302 	/* Lock file table */
303 	mutex_lock(&nlm_file_mutex);
304 
305 	/* If there are no more locks etc, delete the file */
306 	if (--file->f_count == 0 && !nlm_file_inuse(file))
307 		nlm_delete_file(file);
308 
309 	mutex_unlock(&nlm_file_mutex);
310 }
311 
312 /*
313  * Helpers function for resource traversal
314  *
315  * nlmsvc_mark_host:
316  *	used by the garbage collector; simply sets h_inuse only for those
317  *	hosts, which passed network check.
318  *	Always returns 0.
319  *
320  * nlmsvc_same_host:
321  *	returns 1 iff the two hosts match. Used to release
322  *	all resources bound to a specific host.
323  *
324  * nlmsvc_is_client:
325  *	returns 1 iff the host is a client.
326  *	Used by nlmsvc_invalidate_all
327  */
328 
329 static int
nlmsvc_mark_host(void * data,struct nlm_host * hint)330 nlmsvc_mark_host(void *data, struct nlm_host *hint)
331 {
332 	struct nlm_host *host = data;
333 
334 	if ((hint->net == NULL) ||
335 	    (host->net == hint->net))
336 		host->h_inuse = 1;
337 	return 0;
338 }
339 
340 static int
nlmsvc_same_host(void * data,struct nlm_host * other)341 nlmsvc_same_host(void *data, struct nlm_host *other)
342 {
343 	struct nlm_host *host = data;
344 
345 	return host == other;
346 }
347 
348 static int
nlmsvc_is_client(void * data,struct nlm_host * dummy)349 nlmsvc_is_client(void *data, struct nlm_host *dummy)
350 {
351 	struct nlm_host *host = data;
352 
353 	if (host->h_server) {
354 		/* we are destroying locks even though the client
355 		 * hasn't asked us too, so don't unmonitor the
356 		 * client
357 		 */
358 		if (host->h_nsmhandle)
359 			host->h_nsmhandle->sm_sticky = 1;
360 		return 1;
361 	} else
362 		return 0;
363 }
364 
365 /*
366  * Mark all hosts that still hold resources
367  */
368 void
nlmsvc_mark_resources(struct net * net)369 nlmsvc_mark_resources(struct net *net)
370 {
371 	struct nlm_host hint;
372 
373 	dprintk("lockd: %s for net %x\n", __func__, net ? net->ns.inum : 0);
374 	hint.net = net;
375 	nlm_traverse_files(&hint, nlmsvc_mark_host, NULL);
376 }
377 
378 /*
379  * Release all resources held by the given client
380  */
381 void
nlmsvc_free_host_resources(struct nlm_host * host)382 nlmsvc_free_host_resources(struct nlm_host *host)
383 {
384 	dprintk("lockd: nlmsvc_free_host_resources\n");
385 
386 	if (nlm_traverse_files(host, nlmsvc_same_host, NULL)) {
387 		printk(KERN_WARNING
388 			"lockd: couldn't remove all locks held by %s\n",
389 			host->h_name);
390 		BUG();
391 	}
392 }
393 
394 /**
395  * nlmsvc_invalidate_all - remove all locks held for clients
396  *
397  * Release all locks held by NFS clients.
398  *
399  */
400 void
nlmsvc_invalidate_all(void)401 nlmsvc_invalidate_all(void)
402 {
403 	/*
404 	 * Previously, the code would call
405 	 * nlmsvc_free_host_resources for each client in
406 	 * turn, which is about as inefficient as it gets.
407 	 * Now we just do it once in nlm_traverse_files.
408 	 */
409 	nlm_traverse_files(NULL, nlmsvc_is_client, NULL);
410 }
411 
412 static int
nlmsvc_match_sb(void * datap,struct nlm_file * file)413 nlmsvc_match_sb(void *datap, struct nlm_file *file)
414 {
415 	struct super_block *sb = datap;
416 
417 	return sb == locks_inode(file->f_file)->i_sb;
418 }
419 
420 /**
421  * nlmsvc_unlock_all_by_sb - release locks held on this file system
422  * @sb: super block
423  *
424  * Release all locks held by clients accessing this file system.
425  */
426 int
nlmsvc_unlock_all_by_sb(struct super_block * sb)427 nlmsvc_unlock_all_by_sb(struct super_block *sb)
428 {
429 	int ret;
430 
431 	ret = nlm_traverse_files(sb, nlmsvc_always_match, nlmsvc_match_sb);
432 	return ret ? -EIO : 0;
433 }
434 EXPORT_SYMBOL_GPL(nlmsvc_unlock_all_by_sb);
435 
436 static int
nlmsvc_match_ip(void * datap,struct nlm_host * host)437 nlmsvc_match_ip(void *datap, struct nlm_host *host)
438 {
439 	return rpc_cmp_addr(nlm_srcaddr(host), datap);
440 }
441 
442 /**
443  * nlmsvc_unlock_all_by_ip - release local locks by IP address
444  * @server_addr: server's IP address as seen by clients
445  *
446  * Release all locks held by clients accessing this host
447  * via the passed in IP address.
448  */
449 int
nlmsvc_unlock_all_by_ip(struct sockaddr * server_addr)450 nlmsvc_unlock_all_by_ip(struct sockaddr *server_addr)
451 {
452 	int ret;
453 
454 	ret = nlm_traverse_files(server_addr, nlmsvc_match_ip, NULL);
455 	return ret ? -EIO : 0;
456 }
457 EXPORT_SYMBOL_GPL(nlmsvc_unlock_all_by_ip);
458