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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/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)
 32 static struct hlist_head        nlm_files[FILE_NRHASH];
 33 static DEFINE_MUTEX(nlm_file_mutex);
 34 
 35 #ifdef NFSD_DEBUG
 36 static 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 
 46 static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
 47 {
 48         struct inode *inode = file_inode(file->f_file);
 49 
 50         dprintk("lockd: %s %s/%ld\n",
 51                 msg, inode->i_sb->s_id, inode->i_ino);
 52 }
 53 #else
 54 static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
 55 {
 56         return;
 57 }
 58 
 59 static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
 60 {
 61         return;
 62 }
 63 #endif
 64 
 65 static 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 /*
 75  * Lookup file info. If it doesn't exist, create a file info struct
 76  * and open a (VFS) file for the given inode.
 77  *
 78  * FIXME:
 79  * Note that we open the file O_RDONLY even when creating write locks.
 80  * This is not quite right, but for now, we assume the client performs
 81  * the proper R/W checking.
 82  */
 83 __be32
 84 nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
 85                                         struct nfs_fh *f)
 86 {
 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, &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         spin_lock(&inode->i_lock);
173         for (fl = inode->i_flock; fl; fl = fl->fl_next) {
174                 if (fl->fl_lmops != &nlmsvc_lock_operations)
175                         continue;
176 
177                 /* update current lock count */
178                 file->f_locks++;
179 
180                 lockhost = (struct nlm_host *) fl->fl_owner;
181                 if (match(lockhost, host)) {
182                         struct file_lock lock = *fl;
183 
184                         spin_unlock(&inode->i_lock);
185                         lock.fl_type  = F_UNLCK;
186                         lock.fl_start = 0;
187                         lock.fl_end   = OFFSET_MAX;
188                         if (vfs_lock_file(file->f_file, F_SETLK, &lock, NULL) < 0) {
189                                 printk("lockd: unlock failure in %s:%d\n",
190                                                 __FILE__, __LINE__);
191                                 return 1;
192                         }
193                         goto again;
194                 }
195         }
196         spin_unlock(&inode->i_lock);
197 
198         return 0;
199 }
200 
201 static int
202 nlmsvc_always_match(void *dummy1, struct nlm_host *dummy2)
203 {
204         return 1;
205 }
206 
207 /*
208  * Inspect a single file
209  */
210 static inline int
211 nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, nlm_host_match_fn_t match)
212 {
213         nlmsvc_traverse_blocks(host, file, match);
214         nlmsvc_traverse_shares(host, file, match);
215         return nlm_traverse_locks(host, file, match);
216 }
217 
218 /*
219  * Quick check whether there are still any locks, blocks or
220  * shares on a given file.
221  */
222 static inline int
223 nlm_file_inuse(struct nlm_file *file)
224 {
225         struct inode     *inode = nlmsvc_file_inode(file);
226         struct file_lock *fl;
227 
228         if (file->f_count || !list_empty(&file->f_blocks) || file->f_shares)
229                 return 1;
230 
231         spin_lock(&inode->i_lock);
232         for (fl = inode->i_flock; fl; fl = fl->fl_next) {
233                 if (fl->fl_lmops == &nlmsvc_lock_operations) {
234                         spin_unlock(&inode->i_lock);
235                         return 1;
236                 }
237         }
238         spin_unlock(&inode->i_lock);
239         file->f_locks = 0;
240         return 0;
241 }
242 
243 /*
244  * Loop over all files in the file table.
245  */
246 static int
247 nlm_traverse_files(void *data, nlm_host_match_fn_t match,
248                 int (*is_failover_file)(void *data, struct nlm_file *file))
249 {
250         struct hlist_node *next;
251         struct nlm_file *file;
252         int i, ret = 0;
253 
254         mutex_lock(&nlm_file_mutex);
255         for (i = 0; i < FILE_NRHASH; i++) {
256                 hlist_for_each_entry_safe(file, next, &nlm_files[i], f_list) {
257                         if (is_failover_file && !is_failover_file(data, file))
258                                 continue;
259                         file->f_count++;
260                         mutex_unlock(&nlm_file_mutex);
261 
262                         /* Traverse locks, blocks and shares of this file
263                          * and update file->f_locks count */
264                         if (nlm_inspect_file(data, file, match))
265                                 ret = 1;
266 
267                         mutex_lock(&nlm_file_mutex);
268                         file->f_count--;
269                         /* No more references to this file. Let go of it. */
270                         if (list_empty(&file->f_blocks) && !file->f_locks
271                          && !file->f_shares && !file->f_count) {
272                                 hlist_del(&file->f_list);
273                                 nlmsvc_ops->fclose(file->f_file);
274                                 kfree(file);
275                         }
276                 }
277         }
278         mutex_unlock(&nlm_file_mutex);
279         return ret;
280 }
281 
282 /*
283  * Release file. If there are no more remote locks on this file,
284  * close it and free the handle.
285  *
286  * Note that we can't do proper reference counting without major
287  * contortions because the code in fs/locks.c creates, deletes and
288  * splits locks without notification. Our only way is to walk the
289  * entire lock list each time we remove a lock.
290  */
291 void
292 nlm_release_file(struct nlm_file *file)
293 {
294         dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
295                                 file, file->f_count);
296 
297         /* Lock file table */
298         mutex_lock(&nlm_file_mutex);
299 
300         /* If there are no more locks etc, delete the file */
301         if (--file->f_count == 0 && !nlm_file_inuse(file))
302                 nlm_delete_file(file);
303 
304         mutex_unlock(&nlm_file_mutex);
305 }
306 
307 /*
308  * Helpers function for resource traversal
309  *
310  * nlmsvc_mark_host:
311  *      used by the garbage collector; simply sets h_inuse only for those
312  *      hosts, which passed network check.
313  *      Always returns 0.
314  *
315  * nlmsvc_same_host:
316  *      returns 1 iff the two hosts match. Used to release
317  *      all resources bound to a specific host.
318  *
319  * nlmsvc_is_client:
320  *      returns 1 iff the host is a client.
321  *      Used by nlmsvc_invalidate_all
322  */
323 
324 static int
325 nlmsvc_mark_host(void *data, struct nlm_host *hint)
326 {
327         struct nlm_host *host = data;
328 
329         if ((hint->net == NULL) ||
330             (host->net == hint->net))
331                 host->h_inuse = 1;
332         return 0;
333 }
334 
335 static int
336 nlmsvc_same_host(void *data, struct nlm_host *other)
337 {
338         struct nlm_host *host = data;
339 
340         return host == other;
341 }
342 
343 static int
344 nlmsvc_is_client(void *data, struct nlm_host *dummy)
345 {
346         struct nlm_host *host = data;
347 
348         if (host->h_server) {
349                 /* we are destroying locks even though the client
350                  * hasn't asked us too, so don't unmonitor the
351                  * client
352                  */
353                 if (host->h_nsmhandle)
354                         host->h_nsmhandle->sm_sticky = 1;
355                 return 1;
356         } else
357                 return 0;
358 }
359 
360 /*
361  * Mark all hosts that still hold resources
362  */
363 void
364 nlmsvc_mark_resources(struct net *net)
365 {
366         struct nlm_host hint;
367 
368         dprintk("lockd: nlmsvc_mark_resources for net %p\n", net);
369         hint.net = net;
370         nlm_traverse_files(&hint, nlmsvc_mark_host, NULL);
371 }
372 
373 /*
374  * Release all resources held by the given client
375  */
376 void
377 nlmsvc_free_host_resources(struct nlm_host *host)
378 {
379         dprintk("lockd: nlmsvc_free_host_resources\n");
380 
381         if (nlm_traverse_files(host, nlmsvc_same_host, NULL)) {
382                 printk(KERN_WARNING
383                         "lockd: couldn't remove all locks held by %s\n",
384                         host->h_name);
385                 BUG();
386         }
387 }
388 
389 /**
390  * nlmsvc_invalidate_all - remove all locks held for clients
391  *
392  * Release all locks held by NFS clients.
393  *
394  */
395 void
396 nlmsvc_invalidate_all(void)
397 {
398         /*
399          * Previously, the code would call
400          * nlmsvc_free_host_resources for each client in
401          * turn, which is about as inefficient as it gets.
402          * Now we just do it once in nlm_traverse_files.
403          */
404         nlm_traverse_files(NULL, nlmsvc_is_client, NULL);
405 }
406 
407 static int
408 nlmsvc_match_sb(void *datap, struct nlm_file *file)
409 {
410         struct super_block *sb = datap;
411 
412         return sb == file->f_file->f_path.dentry->d_sb;
413 }
414 
415 /**
416  * nlmsvc_unlock_all_by_sb - release locks held on this file system
417  * @sb: super block
418  *
419  * Release all locks held by clients accessing this file system.
420  */
421 int
422 nlmsvc_unlock_all_by_sb(struct super_block *sb)
423 {
424         int ret;
425 
426         ret = nlm_traverse_files(sb, nlmsvc_always_match, nlmsvc_match_sb);
427         return ret ? -EIO : 0;
428 }
429 EXPORT_SYMBOL_GPL(nlmsvc_unlock_all_by_sb);
430 
431 static int
432 nlmsvc_match_ip(void *datap, struct nlm_host *host)
433 {
434         return rpc_cmp_addr(nlm_srcaddr(host), datap);
435 }
436 
437 /**
438  * nlmsvc_unlock_all_by_ip - release local locks by IP address
439  * @server_addr: server's IP address as seen by clients
440  *
441  * Release all locks held by clients accessing this host
442  * via the passed in IP address.
443  */
444 int
445 nlmsvc_unlock_all_by_ip(struct sockaddr *server_addr)
446 {
447         int ret;
448 
449         ret = nlm_traverse_files(server_addr, nlmsvc_match_ip, NULL);
450         return ret ? -EIO : 0;
451 }
452 EXPORT_SYMBOL_GPL(nlmsvc_unlock_all_by_ip);
453 

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