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

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