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Linux/fs/lockd/svcsubs.c

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  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
 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 
 45 static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
 46 {
 47         struct inode *inode = file_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
 53 static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
 54 {
 55         return;
 56 }
 57 
 58 static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
 59 {
 60         return;
 61 }
 62 #endif
 63 
 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
 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
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 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
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
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
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
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
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
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
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
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
369 nlmsvc_mark_resources(struct net *net)
370 {
371         struct nlm_host hint;
372 
373         dprintk("lockd: nlmsvc_mark_resources for net %p\n", net);
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
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
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
413 nlmsvc_match_sb(void *datap, struct nlm_file *file)
414 {
415         struct super_block *sb = datap;
416 
417         return sb == file_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
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
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
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 

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