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)
30 static struct hlist_head nlm_files[FILE_NRHASH];
31 static DEFINE_MUTEX(nlm_file_mutex);
32
33 #ifdef NFSD_DEBUG
34 static 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
44 static 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
52 static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
53 {
54 return;
55 }
56
57 static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
58 {
59 return;
60 }
61 #endif
62
63 static 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 /*
73 * Lookup file info. If it doesn't exist, create a file info struct
74 * and open a (VFS) file for the given inode.
75 *
76 * FIXME:
77 * Note that we open the file O_RDONLY even when creating write locks.
78 * This is not quite right, but for now, we assume the client performs
79 * the proper R/W checking.
80 */
81 __be32
82 nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
83 struct nfs_fh *f)
84 {
85 struct hlist_node *pos;
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, pos, &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
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
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 nlm_host *lockhost;
168
169 again:
170 file->f_locks = 0;
171 for (fl = inode->i_flock; fl; fl = fl->fl_next) {
172 if (fl->fl_lmops != &nlmsvc_lock_operations)
173 continue;
174
175 /* update current lock count */
176 file->f_locks++;
177
178 lockhost = (struct nlm_host *) fl->fl_owner;
179 if (match(lockhost, host)) {
180 struct file_lock lock = *fl;
181
182 lock.fl_type = F_UNLCK;
183 lock.fl_start = 0;
184 lock.fl_end = OFFSET_MAX;
185 if (vfs_lock_file(file->f_file, F_SETLK, &lock, NULL) < 0) {
186 printk("lockd: unlock failure in %s:%d\n",
187 __FILE__, __LINE__);
188 return 1;
189 }
190 goto again;
191 }
192 }
193
194 return 0;
195 }
196
197 /*
198 * Inspect a single file
199 */
200 static inline int
201 nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, nlm_host_match_fn_t match)
202 {
203 nlmsvc_traverse_blocks(host, file, match);
204 nlmsvc_traverse_shares(host, file, match);
205 return nlm_traverse_locks(host, file, match);
206 }
207
208 /*
209 * Quick check whether there are still any locks, blocks or
210 * shares on a given file.
211 */
212 static inline int
213 nlm_file_inuse(struct nlm_file *file)
214 {
215 struct inode *inode = nlmsvc_file_inode(file);
216 struct file_lock *fl;
217
218 if (file->f_count || !list_empty(&file->f_blocks) || file->f_shares)
219 return 1;
220
221 for (fl = inode->i_flock; fl; fl = fl->fl_next) {
222 if (fl->fl_lmops == &nlmsvc_lock_operations)
223 return 1;
224 }
225 file->f_locks = 0;
226 return 0;
227 }
228
229 /*
230 * Loop over all files in the file table.
231 */
232 static int
233 nlm_traverse_files(struct nlm_host *host, nlm_host_match_fn_t match)
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 file->f_count++;
243 mutex_unlock(&nlm_file_mutex);
244
245 /* Traverse locks, blocks and shares of this file
246 * and update file->f_locks count */
247 if (nlm_inspect_file(host, file, match))
248 ret = 1;
249
250 mutex_lock(&nlm_file_mutex);
251 file->f_count--;
252 /* No more references to this file. Let go of it. */
253 if (list_empty(&file->f_blocks) && !file->f_locks
254 && !file->f_shares && !file->f_count) {
255 hlist_del(&file->f_list);
256 nlmsvc_ops->fclose(file->f_file);
257 kfree(file);
258 }
259 }
260 }
261 mutex_unlock(&nlm_file_mutex);
262 return ret;
263 }
264
265 /*
266 * Release file. If there are no more remote locks on this file,
267 * close it and free the handle.
268 *
269 * Note that we can't do proper reference counting without major
270 * contortions because the code in fs/locks.c creates, deletes and
271 * splits locks without notification. Our only way is to walk the
272 * entire lock list each time we remove a lock.
273 */
274 void
275 nlm_release_file(struct nlm_file *file)
276 {
277 dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
278 file, file->f_count);
279
280 /* Lock file table */
281 mutex_lock(&nlm_file_mutex);
282
283 /* If there are no more locks etc, delete the file */
284 if (--file->f_count == 0 && !nlm_file_inuse(file))
285 nlm_delete_file(file);
286
287 mutex_unlock(&nlm_file_mutex);
288 }
289
290 /*
291 * Helpers function for resource traversal
292 *
293 * nlmsvc_mark_host:
294 * used by the garbage collector; simply sets h_inuse.
295 * Always returns 0.
296 *
297 * nlmsvc_same_host:
298 * returns 1 iff the two hosts match. Used to release
299 * all resources bound to a specific host.
300 *
301 * nlmsvc_is_client:
302 * returns 1 iff the host is a client.
303 * Used by nlmsvc_invalidate_all
304 */
305 static int
306 nlmsvc_mark_host(struct nlm_host *host, struct nlm_host *dummy)
307 {
308 host->h_inuse = 1;
309 return 0;
310 }
311
312 static int
313 nlmsvc_same_host(struct nlm_host *host, struct nlm_host *other)
314 {
315 return host == other;
316 }
317
318 static int
319 nlmsvc_is_client(struct nlm_host *host, struct nlm_host *dummy)
320 {
321 if (host->h_server) {
322 /* we are destroying locks even though the client
323 * hasn't asked us too, so don't unmonitor the
324 * client
325 */
326 if (host->h_nsmhandle)
327 host->h_nsmhandle->sm_sticky = 1;
328 return 1;
329 } else
330 return 0;
331 }
332
333 /*
334 * Mark all hosts that still hold resources
335 */
336 void
337 nlmsvc_mark_resources(void)
338 {
339 dprintk("lockd: nlmsvc_mark_resources\n");
340 nlm_traverse_files(NULL, nlmsvc_mark_host);
341 }
342
343 /*
344 * Release all resources held by the given client
345 */
346 void
347 nlmsvc_free_host_resources(struct nlm_host *host)
348 {
349 dprintk("lockd: nlmsvc_free_host_resources\n");
350
351 if (nlm_traverse_files(host, nlmsvc_same_host)) {
352 printk(KERN_WARNING
353 "lockd: couldn't remove all locks held by %s\n",
354 host->h_name);
355 BUG();
356 }
357 }
358
359 /*
360 * Remove all locks held for clients
361 */
362 void
363 nlmsvc_invalidate_all(void)
364 {
365 /* Release all locks held by NFS clients.
366 * Previously, the code would call
367 * nlmsvc_free_host_resources for each client in
368 * turn, which is about as inefficient as it gets.
369 * Now we just do it once in nlm_traverse_files.
370 */
371 nlm_traverse_files(NULL, nlmsvc_is_client);
372 }
373
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