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Linux/fs/lockd/svcsubs.c

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  1 // SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  * linux/fs/lockd/svcsubs.c
  4  *
  5  * Various support routines for the NLM server.
  6  *
  7  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
  8  */
  9 
 10 #include <linux/types.h>
 11 #include <linux/string.h>
 12 #include <linux/time.h>
 13 #include <linux/in.h>
 14 #include <linux/slab.h>
 15 #include <linux/mutex.h>
 16 #include <linux/sunrpc/svc.h>
 17 #include <linux/sunrpc/addr.h>
 18 #include <linux/lockd/lockd.h>
 19 #include <linux/lockd/share.h>
 20 #include <linux/module.h>
 21 #include <linux/mount.h>
 22 #include <uapi/linux/nfs2.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 CONFIG_SUNRPC_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 = locks_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 file_lock_context *flctx = inode->i_flctx;
169         struct nlm_host  *lockhost;
170 
171         if (!flctx || list_empty_careful(&flctx->flc_posix))
172                 return 0;
173 again:
174         file->f_locks = 0;
175         spin_lock(&flctx->flc_lock);
176         list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
177                 if (fl->fl_lmops != &nlmsvc_lock_operations)
178                         continue;
179 
180                 /* update current lock count */
181                 file->f_locks++;
182 
183                 lockhost = ((struct nlm_lockowner *)fl->fl_owner)->host;
184                 if (match(lockhost, host)) {
185                         struct file_lock lock = *fl;
186 
187                         spin_unlock(&flctx->flc_lock);
188                         lock.fl_type  = F_UNLCK;
189                         lock.fl_start = 0;
190                         lock.fl_end   = OFFSET_MAX;
191                         if (vfs_lock_file(file->f_file, F_SETLK, &lock, NULL) < 0) {
192                                 printk("lockd: unlock failure in %s:%d\n",
193                                                 __FILE__, __LINE__);
194                                 return 1;
195                         }
196                         goto again;
197                 }
198         }
199         spin_unlock(&flctx->flc_lock);
200 
201         return 0;
202 }
203 
204 static int
205 nlmsvc_always_match(void *dummy1, struct nlm_host *dummy2)
206 {
207         return 1;
208 }
209 
210 /*
211  * Inspect a single file
212  */
213 static inline int
214 nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, nlm_host_match_fn_t match)
215 {
216         nlmsvc_traverse_blocks(host, file, match);
217         nlmsvc_traverse_shares(host, file, match);
218         return nlm_traverse_locks(host, file, match);
219 }
220 
221 /*
222  * Quick check whether there are still any locks, blocks or
223  * shares on a given file.
224  */
225 static inline int
226 nlm_file_inuse(struct nlm_file *file)
227 {
228         struct inode     *inode = nlmsvc_file_inode(file);
229         struct file_lock *fl;
230         struct file_lock_context *flctx = inode->i_flctx;
231 
232         if (file->f_count || !list_empty(&file->f_blocks) || file->f_shares)
233                 return 1;
234 
235         if (flctx && !list_empty_careful(&flctx->flc_posix)) {
236                 spin_lock(&flctx->flc_lock);
237                 list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
238                         if (fl->fl_lmops == &nlmsvc_lock_operations) {
239                                 spin_unlock(&flctx->flc_lock);
240                                 return 1;
241                         }
242                 }
243                 spin_unlock(&flctx->flc_lock);
244         }
245         file->f_locks = 0;
246         return 0;
247 }
248 
249 /*
250  * Loop over all files in the file table.
251  */
252 static int
253 nlm_traverse_files(void *data, nlm_host_match_fn_t match,
254                 int (*is_failover_file)(void *data, struct nlm_file *file))
255 {
256         struct hlist_node *next;
257         struct nlm_file *file;
258         int i, ret = 0;
259 
260         mutex_lock(&nlm_file_mutex);
261         for (i = 0; i < FILE_NRHASH; i++) {
262                 hlist_for_each_entry_safe(file, next, &nlm_files[i], f_list) {
263                         if (is_failover_file && !is_failover_file(data, file))
264                                 continue;
265                         file->f_count++;
266                         mutex_unlock(&nlm_file_mutex);
267 
268                         /* Traverse locks, blocks and shares of this file
269                          * and update file->f_locks count */
270                         if (nlm_inspect_file(data, file, match))
271                                 ret = 1;
272 
273                         mutex_lock(&nlm_file_mutex);
274                         file->f_count--;
275                         /* No more references to this file. Let go of it. */
276                         if (list_empty(&file->f_blocks) && !file->f_locks
277                          && !file->f_shares && !file->f_count) {
278                                 hlist_del(&file->f_list);
279                                 nlmsvc_ops->fclose(file->f_file);
280                                 kfree(file);
281                         }
282                 }
283         }
284         mutex_unlock(&nlm_file_mutex);
285         return ret;
286 }
287 
288 /*
289  * Release file. If there are no more remote locks on this file,
290  * close it and free the handle.
291  *
292  * Note that we can't do proper reference counting without major
293  * contortions because the code in fs/locks.c creates, deletes and
294  * splits locks without notification. Our only way is to walk the
295  * entire lock list each time we remove a lock.
296  */
297 void
298 nlm_release_file(struct nlm_file *file)
299 {
300         dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
301                                 file, file->f_count);
302 
303         /* Lock file table */
304         mutex_lock(&nlm_file_mutex);
305 
306         /* If there are no more locks etc, delete the file */
307         if (--file->f_count == 0 && !nlm_file_inuse(file))
308                 nlm_delete_file(file);
309 
310         mutex_unlock(&nlm_file_mutex);
311 }
312 
313 /*
314  * Helpers function for resource traversal
315  *
316  * nlmsvc_mark_host:
317  *      used by the garbage collector; simply sets h_inuse only for those
318  *      hosts, which passed network check.
319  *      Always returns 0.
320  *
321  * nlmsvc_same_host:
322  *      returns 1 iff the two hosts match. Used to release
323  *      all resources bound to a specific host.
324  *
325  * nlmsvc_is_client:
326  *      returns 1 iff the host is a client.
327  *      Used by nlmsvc_invalidate_all
328  */
329 
330 static int
331 nlmsvc_mark_host(void *data, struct nlm_host *hint)
332 {
333         struct nlm_host *host = data;
334 
335         if ((hint->net == NULL) ||
336             (host->net == hint->net))
337                 host->h_inuse = 1;
338         return 0;
339 }
340 
341 static int
342 nlmsvc_same_host(void *data, struct nlm_host *other)
343 {
344         struct nlm_host *host = data;
345 
346         return host == other;
347 }
348 
349 static int
350 nlmsvc_is_client(void *data, struct nlm_host *dummy)
351 {
352         struct nlm_host *host = data;
353 
354         if (host->h_server) {
355                 /* we are destroying locks even though the client
356                  * hasn't asked us too, so don't unmonitor the
357                  * client
358                  */
359                 if (host->h_nsmhandle)
360                         host->h_nsmhandle->sm_sticky = 1;
361                 return 1;
362         } else
363                 return 0;
364 }
365 
366 /*
367  * Mark all hosts that still hold resources
368  */
369 void
370 nlmsvc_mark_resources(struct net *net)
371 {
372         struct nlm_host hint;
373 
374         dprintk("lockd: %s for net %x\n", __func__, net ? net->ns.inum : 0);
375         hint.net = net;
376         nlm_traverse_files(&hint, nlmsvc_mark_host, NULL);
377 }
378 
379 /*
380  * Release all resources held by the given client
381  */
382 void
383 nlmsvc_free_host_resources(struct nlm_host *host)
384 {
385         dprintk("lockd: nlmsvc_free_host_resources\n");
386 
387         if (nlm_traverse_files(host, nlmsvc_same_host, NULL)) {
388                 printk(KERN_WARNING
389                         "lockd: couldn't remove all locks held by %s\n",
390                         host->h_name);
391                 BUG();
392         }
393 }
394 
395 /**
396  * nlmsvc_invalidate_all - remove all locks held for clients
397  *
398  * Release all locks held by NFS clients.
399  *
400  */
401 void
402 nlmsvc_invalidate_all(void)
403 {
404         /*
405          * Previously, the code would call
406          * nlmsvc_free_host_resources for each client in
407          * turn, which is about as inefficient as it gets.
408          * Now we just do it once in nlm_traverse_files.
409          */
410         nlm_traverse_files(NULL, nlmsvc_is_client, NULL);
411 }
412 
413 static int
414 nlmsvc_match_sb(void *datap, struct nlm_file *file)
415 {
416         struct super_block *sb = datap;
417 
418         return sb == locks_inode(file->f_file)->i_sb;
419 }
420 
421 /**
422  * nlmsvc_unlock_all_by_sb - release locks held on this file system
423  * @sb: super block
424  *
425  * Release all locks held by clients accessing this file system.
426  */
427 int
428 nlmsvc_unlock_all_by_sb(struct super_block *sb)
429 {
430         int ret;
431 
432         ret = nlm_traverse_files(sb, nlmsvc_always_match, nlmsvc_match_sb);
433         return ret ? -EIO : 0;
434 }
435 EXPORT_SYMBOL_GPL(nlmsvc_unlock_all_by_sb);
436 
437 static int
438 nlmsvc_match_ip(void *datap, struct nlm_host *host)
439 {
440         return rpc_cmp_addr(nlm_srcaddr(host), datap);
441 }
442 
443 /**
444  * nlmsvc_unlock_all_by_ip - release local locks by IP address
445  * @server_addr: server's IP address as seen by clients
446  *
447  * Release all locks held by clients accessing this host
448  * via the passed in IP address.
449  */
450 int
451 nlmsvc_unlock_all_by_ip(struct sockaddr *server_addr)
452 {
453         int ret;
454 
455         ret = nlm_traverse_files(server_addr, nlmsvc_match_ip, NULL);
456         return ret ? -EIO : 0;
457 }
458 EXPORT_SYMBOL_GPL(nlmsvc_unlock_all_by_ip);
459 

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