~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/fs/lockd/clntproc.c

Version: ~ [ linux-5.0-rc6 ] ~ [ linux-4.20.10 ] ~ [ linux-4.19.23 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.101 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.158 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.174 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.134 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.63 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * linux/fs/lockd/clntproc.c
  3  *
  4  * RPC procedures for the client side NLM implementation
  5  *
  6  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
  7  */
  8 
  9 #include <linux/module.h>
 10 #include <linux/slab.h>
 11 #include <linux/types.h>
 12 #include <linux/errno.h>
 13 #include <linux/fs.h>
 14 #include <linux/nfs_fs.h>
 15 #include <linux/utsname.h>
 16 #include <linux/freezer.h>
 17 #include <linux/sunrpc/clnt.h>
 18 #include <linux/sunrpc/svc.h>
 19 #include <linux/lockd/lockd.h>
 20 
 21 #define NLMDBG_FACILITY         NLMDBG_CLIENT
 22 #define NLMCLNT_GRACE_WAIT      (5*HZ)
 23 #define NLMCLNT_POLL_TIMEOUT    (30*HZ)
 24 #define NLMCLNT_MAX_RETRIES     3
 25 
 26 static int      nlmclnt_test(struct nlm_rqst *, struct file_lock *);
 27 static int      nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
 28 static int      nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
 29 static int      nlm_stat_to_errno(__be32 stat);
 30 static void     nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
 31 static int      nlmclnt_cancel(struct nlm_host *, int , struct file_lock *);
 32 
 33 static const struct rpc_call_ops nlmclnt_unlock_ops;
 34 static const struct rpc_call_ops nlmclnt_cancel_ops;
 35 
 36 /*
 37  * Cookie counter for NLM requests
 38  */
 39 static atomic_t nlm_cookie = ATOMIC_INIT(0x1234);
 40 
 41 void nlmclnt_next_cookie(struct nlm_cookie *c)
 42 {
 43         u32     cookie = atomic_inc_return(&nlm_cookie);
 44 
 45         memcpy(c->data, &cookie, 4);
 46         c->len=4;
 47 }
 48 
 49 static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner)
 50 {
 51         refcount_inc(&lockowner->count);
 52         return lockowner;
 53 }
 54 
 55 static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
 56 {
 57         if (!refcount_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
 58                 return;
 59         list_del(&lockowner->list);
 60         spin_unlock(&lockowner->host->h_lock);
 61         nlmclnt_release_host(lockowner->host);
 62         kfree(lockowner);
 63 }
 64 
 65 static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
 66 {
 67         struct nlm_lockowner *lockowner;
 68         list_for_each_entry(lockowner, &host->h_lockowners, list) {
 69                 if (lockowner->pid == pid)
 70                         return -EBUSY;
 71         }
 72         return 0;
 73 }
 74 
 75 static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
 76 {
 77         uint32_t res;
 78         do {
 79                 res = host->h_pidcount++;
 80         } while (nlm_pidbusy(host, res) < 0);
 81         return res;
 82 }
 83 
 84 static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
 85 {
 86         struct nlm_lockowner *lockowner;
 87         list_for_each_entry(lockowner, &host->h_lockowners, list) {
 88                 if (lockowner->owner != owner)
 89                         continue;
 90                 return nlm_get_lockowner(lockowner);
 91         }
 92         return NULL;
 93 }
 94 
 95 static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
 96 {
 97         struct nlm_lockowner *res, *new = NULL;
 98 
 99         spin_lock(&host->h_lock);
100         res = __nlm_find_lockowner(host, owner);
101         if (res == NULL) {
102                 spin_unlock(&host->h_lock);
103                 new = kmalloc(sizeof(*new), GFP_KERNEL);
104                 spin_lock(&host->h_lock);
105                 res = __nlm_find_lockowner(host, owner);
106                 if (res == NULL && new != NULL) {
107                         res = new;
108                         refcount_set(&new->count, 1);
109                         new->owner = owner;
110                         new->pid = __nlm_alloc_pid(host);
111                         new->host = nlm_get_host(host);
112                         list_add(&new->list, &host->h_lockowners);
113                         new = NULL;
114                 }
115         }
116         spin_unlock(&host->h_lock);
117         kfree(new);
118         return res;
119 }
120 
121 /*
122  * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
123  */
124 static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
125 {
126         struct nlm_args *argp = &req->a_args;
127         struct nlm_lock *lock = &argp->lock;
128         char *nodename = req->a_host->h_rpcclnt->cl_nodename;
129 
130         nlmclnt_next_cookie(&argp->cookie);
131         memcpy(&lock->fh, NFS_FH(locks_inode(fl->fl_file)), sizeof(struct nfs_fh));
132         lock->caller  = nodename;
133         lock->oh.data = req->a_owner;
134         lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
135                                 (unsigned int)fl->fl_u.nfs_fl.owner->pid,
136                                 nodename);
137         lock->svid = fl->fl_u.nfs_fl.owner->pid;
138         lock->fl.fl_start = fl->fl_start;
139         lock->fl.fl_end = fl->fl_end;
140         lock->fl.fl_type = fl->fl_type;
141 }
142 
143 static void nlmclnt_release_lockargs(struct nlm_rqst *req)
144 {
145         WARN_ON_ONCE(req->a_args.lock.fl.fl_ops != NULL);
146 }
147 
148 /**
149  * nlmclnt_proc - Perform a single client-side lock request
150  * @host: address of a valid nlm_host context representing the NLM server
151  * @cmd: fcntl-style file lock operation to perform
152  * @fl: address of arguments for the lock operation
153  * @data: address of data to be sent to callback operations
154  *
155  */
156 int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl, void *data)
157 {
158         struct nlm_rqst         *call;
159         int                     status;
160         const struct nlmclnt_operations *nlmclnt_ops = host->h_nlmclnt_ops;
161 
162         call = nlm_alloc_call(host);
163         if (call == NULL)
164                 return -ENOMEM;
165 
166         if (nlmclnt_ops && nlmclnt_ops->nlmclnt_alloc_call)
167                 nlmclnt_ops->nlmclnt_alloc_call(data);
168 
169         nlmclnt_locks_init_private(fl, host);
170         if (!fl->fl_u.nfs_fl.owner) {
171                 /* lockowner allocation has failed */
172                 nlmclnt_release_call(call);
173                 return -ENOMEM;
174         }
175         /* Set up the argument struct */
176         nlmclnt_setlockargs(call, fl);
177         call->a_callback_data = data;
178 
179         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
180                 if (fl->fl_type != F_UNLCK) {
181                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
182                         status = nlmclnt_lock(call, fl);
183                 } else
184                         status = nlmclnt_unlock(call, fl);
185         } else if (IS_GETLK(cmd))
186                 status = nlmclnt_test(call, fl);
187         else
188                 status = -EINVAL;
189         fl->fl_ops->fl_release_private(fl);
190         fl->fl_ops = NULL;
191 
192         dprintk("lockd: clnt proc returns %d\n", status);
193         return status;
194 }
195 EXPORT_SYMBOL_GPL(nlmclnt_proc);
196 
197 /*
198  * Allocate an NLM RPC call struct
199  */
200 struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
201 {
202         struct nlm_rqst *call;
203 
204         for(;;) {
205                 call = kzalloc(sizeof(*call), GFP_KERNEL);
206                 if (call != NULL) {
207                         refcount_set(&call->a_count, 1);
208                         locks_init_lock(&call->a_args.lock.fl);
209                         locks_init_lock(&call->a_res.lock.fl);
210                         call->a_host = nlm_get_host(host);
211                         return call;
212                 }
213                 if (signalled())
214                         break;
215                 printk("nlm_alloc_call: failed, waiting for memory\n");
216                 schedule_timeout_interruptible(5*HZ);
217         }
218         return NULL;
219 }
220 
221 void nlmclnt_release_call(struct nlm_rqst *call)
222 {
223         const struct nlmclnt_operations *nlmclnt_ops = call->a_host->h_nlmclnt_ops;
224 
225         if (!refcount_dec_and_test(&call->a_count))
226                 return;
227         if (nlmclnt_ops && nlmclnt_ops->nlmclnt_release_call)
228                 nlmclnt_ops->nlmclnt_release_call(call->a_callback_data);
229         nlmclnt_release_host(call->a_host);
230         nlmclnt_release_lockargs(call);
231         kfree(call);
232 }
233 
234 static void nlmclnt_rpc_release(void *data)
235 {
236         nlmclnt_release_call(data);
237 }
238 
239 static int nlm_wait_on_grace(wait_queue_head_t *queue)
240 {
241         DEFINE_WAIT(wait);
242         int status = -EINTR;
243 
244         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
245         if (!signalled ()) {
246                 schedule_timeout(NLMCLNT_GRACE_WAIT);
247                 try_to_freeze();
248                 if (!signalled ())
249                         status = 0;
250         }
251         finish_wait(queue, &wait);
252         return status;
253 }
254 
255 /*
256  * Generic NLM call
257  */
258 static int
259 nlmclnt_call(const struct cred *cred, struct nlm_rqst *req, u32 proc)
260 {
261         struct nlm_host *host = req->a_host;
262         struct rpc_clnt *clnt;
263         struct nlm_args *argp = &req->a_args;
264         struct nlm_res  *resp = &req->a_res;
265         struct rpc_message msg = {
266                 .rpc_argp       = argp,
267                 .rpc_resp       = resp,
268                 .rpc_cred       = cred,
269         };
270         int             status;
271 
272         dprintk("lockd: call procedure %d on %s\n",
273                         (int)proc, host->h_name);
274 
275         do {
276                 if (host->h_reclaiming && !argp->reclaim)
277                         goto in_grace_period;
278 
279                 /* If we have no RPC client yet, create one. */
280                 if ((clnt = nlm_bind_host(host)) == NULL)
281                         return -ENOLCK;
282                 msg.rpc_proc = &clnt->cl_procinfo[proc];
283 
284                 /* Perform the RPC call. If an error occurs, try again */
285                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
286                         dprintk("lockd: rpc_call returned error %d\n", -status);
287                         switch (status) {
288                         case -EPROTONOSUPPORT:
289                                 status = -EINVAL;
290                                 break;
291                         case -ECONNREFUSED:
292                         case -ETIMEDOUT:
293                         case -ENOTCONN:
294                                 nlm_rebind_host(host);
295                                 status = -EAGAIN;
296                                 break;
297                         case -ERESTARTSYS:
298                                 return signalled () ? -EINTR : status;
299                         default:
300                                 break;
301                         }
302                         break;
303                 } else
304                 if (resp->status == nlm_lck_denied_grace_period) {
305                         dprintk("lockd: server in grace period\n");
306                         if (argp->reclaim) {
307                                 printk(KERN_WARNING
308                                      "lockd: spurious grace period reject?!\n");
309                                 return -ENOLCK;
310                         }
311                 } else {
312                         if (!argp->reclaim) {
313                                 /* We appear to be out of the grace period */
314                                 wake_up_all(&host->h_gracewait);
315                         }
316                         dprintk("lockd: server returns status %d\n",
317                                 ntohl(resp->status));
318                         return 0;       /* Okay, call complete */
319                 }
320 
321 in_grace_period:
322                 /*
323                  * The server has rebooted and appears to be in the grace
324                  * period during which locks are only allowed to be
325                  * reclaimed.
326                  * We can only back off and try again later.
327                  */
328                 status = nlm_wait_on_grace(&host->h_gracewait);
329         } while (status == 0);
330 
331         return status;
332 }
333 
334 /*
335  * Generic NLM call, async version.
336  */
337 static struct rpc_task *__nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
338 {
339         struct nlm_host *host = req->a_host;
340         struct rpc_clnt *clnt;
341         struct rpc_task_setup task_setup_data = {
342                 .rpc_message = msg,
343                 .callback_ops = tk_ops,
344                 .callback_data = req,
345                 .flags = RPC_TASK_ASYNC,
346         };
347 
348         dprintk("lockd: call procedure %d on %s (async)\n",
349                         (int)proc, host->h_name);
350 
351         /* If we have no RPC client yet, create one. */
352         clnt = nlm_bind_host(host);
353         if (clnt == NULL)
354                 goto out_err;
355         msg->rpc_proc = &clnt->cl_procinfo[proc];
356         task_setup_data.rpc_client = clnt;
357 
358         /* bootstrap and kick off the async RPC call */
359         return rpc_run_task(&task_setup_data);
360 out_err:
361         tk_ops->rpc_release(req);
362         return ERR_PTR(-ENOLCK);
363 }
364 
365 static int nlm_do_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
366 {
367         struct rpc_task *task;
368 
369         task = __nlm_async_call(req, proc, msg, tk_ops);
370         if (IS_ERR(task))
371                 return PTR_ERR(task);
372         rpc_put_task(task);
373         return 0;
374 }
375 
376 /*
377  * NLM asynchronous call.
378  */
379 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
380 {
381         struct rpc_message msg = {
382                 .rpc_argp       = &req->a_args,
383                 .rpc_resp       = &req->a_res,
384         };
385         return nlm_do_async_call(req, proc, &msg, tk_ops);
386 }
387 
388 int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
389 {
390         struct rpc_message msg = {
391                 .rpc_argp       = &req->a_res,
392         };
393         return nlm_do_async_call(req, proc, &msg, tk_ops);
394 }
395 
396 /*
397  * NLM client asynchronous call.
398  *
399  * Note that although the calls are asynchronous, and are therefore
400  *      guaranteed to complete, we still always attempt to wait for
401  *      completion in order to be able to correctly track the lock
402  *      state.
403  */
404 static int nlmclnt_async_call(const struct cred *cred, struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
405 {
406         struct rpc_message msg = {
407                 .rpc_argp       = &req->a_args,
408                 .rpc_resp       = &req->a_res,
409                 .rpc_cred       = cred,
410         };
411         struct rpc_task *task;
412         int err;
413 
414         task = __nlm_async_call(req, proc, &msg, tk_ops);
415         if (IS_ERR(task))
416                 return PTR_ERR(task);
417         err = rpc_wait_for_completion_task(task);
418         rpc_put_task(task);
419         return err;
420 }
421 
422 /*
423  * TEST for the presence of a conflicting lock
424  */
425 static int
426 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
427 {
428         int     status;
429 
430         status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_TEST);
431         if (status < 0)
432                 goto out;
433 
434         switch (req->a_res.status) {
435                 case nlm_granted:
436                         fl->fl_type = F_UNLCK;
437                         break;
438                 case nlm_lck_denied:
439                         /*
440                          * Report the conflicting lock back to the application.
441                          */
442                         fl->fl_start = req->a_res.lock.fl.fl_start;
443                         fl->fl_end = req->a_res.lock.fl.fl_end;
444                         fl->fl_type = req->a_res.lock.fl.fl_type;
445                         fl->fl_pid = -req->a_res.lock.fl.fl_pid;
446                         break;
447                 default:
448                         status = nlm_stat_to_errno(req->a_res.status);
449         }
450 out:
451         nlmclnt_release_call(req);
452         return status;
453 }
454 
455 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
456 {
457         spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
458         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
459         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
460         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
461         spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
462 }
463 
464 static void nlmclnt_locks_release_private(struct file_lock *fl)
465 {
466         spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
467         list_del(&fl->fl_u.nfs_fl.list);
468         spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
469         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
470 }
471 
472 static const struct file_lock_operations nlmclnt_lock_ops = {
473         .fl_copy_lock = nlmclnt_locks_copy_lock,
474         .fl_release_private = nlmclnt_locks_release_private,
475 };
476 
477 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
478 {
479         fl->fl_u.nfs_fl.state = 0;
480         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
481         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
482         fl->fl_ops = &nlmclnt_lock_ops;
483 }
484 
485 static int do_vfs_lock(struct file_lock *fl)
486 {
487         return locks_lock_file_wait(fl->fl_file, fl);
488 }
489 
490 /*
491  * LOCK: Try to create a lock
492  *
493  *                      Programmer Harassment Alert
494  *
495  * When given a blocking lock request in a sync RPC call, the HPUX lockd
496  * will faithfully return LCK_BLOCKED but never cares to notify us when
497  * the lock could be granted. This way, our local process could hang
498  * around forever waiting for the callback.
499  *
500  *  Solution A: Implement busy-waiting
501  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
502  *
503  * For now I am implementing solution A, because I hate the idea of
504  * re-implementing lockd for a third time in two months. The async
505  * calls shouldn't be too hard to do, however.
506  *
507  * This is one of the lovely things about standards in the NFS area:
508  * they're so soft and squishy you can't really blame HP for doing this.
509  */
510 static int
511 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
512 {
513         const struct cred *cred = nfs_file_cred(fl->fl_file);
514         struct nlm_host *host = req->a_host;
515         struct nlm_res  *resp = &req->a_res;
516         struct nlm_wait *block = NULL;
517         unsigned char fl_flags = fl->fl_flags;
518         unsigned char fl_type;
519         int status = -ENOLCK;
520 
521         if (nsm_monitor(host) < 0)
522                 goto out;
523         req->a_args.state = nsm_local_state;
524 
525         fl->fl_flags |= FL_ACCESS;
526         status = do_vfs_lock(fl);
527         fl->fl_flags = fl_flags;
528         if (status < 0)
529                 goto out;
530 
531         block = nlmclnt_prepare_block(host, fl);
532 again:
533         /*
534          * Initialise resp->status to a valid non-zero value,
535          * since 0 == nlm_lck_granted
536          */
537         resp->status = nlm_lck_blocked;
538         for(;;) {
539                 /* Reboot protection */
540                 fl->fl_u.nfs_fl.state = host->h_state;
541                 status = nlmclnt_call(cred, req, NLMPROC_LOCK);
542                 if (status < 0)
543                         break;
544                 /* Did a reclaimer thread notify us of a server reboot? */
545                 if (resp->status ==  nlm_lck_denied_grace_period)
546                         continue;
547                 if (resp->status != nlm_lck_blocked)
548                         break;
549                 /* Wait on an NLM blocking lock */
550                 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
551                 if (status < 0)
552                         break;
553                 if (resp->status != nlm_lck_blocked)
554                         break;
555         }
556 
557         /* if we were interrupted while blocking, then cancel the lock request
558          * and exit
559          */
560         if (resp->status == nlm_lck_blocked) {
561                 if (!req->a_args.block)
562                         goto out_unlock;
563                 if (nlmclnt_cancel(host, req->a_args.block, fl) == 0)
564                         goto out_unblock;
565         }
566 
567         if (resp->status == nlm_granted) {
568                 down_read(&host->h_rwsem);
569                 /* Check whether or not the server has rebooted */
570                 if (fl->fl_u.nfs_fl.state != host->h_state) {
571                         up_read(&host->h_rwsem);
572                         goto again;
573                 }
574                 /* Ensure the resulting lock will get added to granted list */
575                 fl->fl_flags |= FL_SLEEP;
576                 if (do_vfs_lock(fl) < 0)
577                         printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __func__);
578                 up_read(&host->h_rwsem);
579                 fl->fl_flags = fl_flags;
580                 status = 0;
581         }
582         if (status < 0)
583                 goto out_unlock;
584         /*
585          * EAGAIN doesn't make sense for sleeping locks, and in some
586          * cases NLM_LCK_DENIED is returned for a permanent error.  So
587          * turn it into an ENOLCK.
588          */
589         if (resp->status == nlm_lck_denied && (fl_flags & FL_SLEEP))
590                 status = -ENOLCK;
591         else
592                 status = nlm_stat_to_errno(resp->status);
593 out_unblock:
594         nlmclnt_finish_block(block);
595 out:
596         nlmclnt_release_call(req);
597         return status;
598 out_unlock:
599         /* Fatal error: ensure that we remove the lock altogether */
600         dprintk("lockd: lock attempt ended in fatal error.\n"
601                 "       Attempting to unlock.\n");
602         nlmclnt_finish_block(block);
603         fl_type = fl->fl_type;
604         fl->fl_type = F_UNLCK;
605         down_read(&host->h_rwsem);
606         do_vfs_lock(fl);
607         up_read(&host->h_rwsem);
608         fl->fl_type = fl_type;
609         fl->fl_flags = fl_flags;
610         nlmclnt_async_call(cred, req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
611         return status;
612 }
613 
614 /*
615  * RECLAIM: Try to reclaim a lock
616  */
617 int
618 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl,
619                 struct nlm_rqst *req)
620 {
621         int             status;
622 
623         memset(req, 0, sizeof(*req));
624         locks_init_lock(&req->a_args.lock.fl);
625         locks_init_lock(&req->a_res.lock.fl);
626         req->a_host  = host;
627 
628         /* Set up the argument struct */
629         nlmclnt_setlockargs(req, fl);
630         req->a_args.reclaim = 1;
631 
632         status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_LOCK);
633         if (status >= 0 && req->a_res.status == nlm_granted)
634                 return 0;
635 
636         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
637                                 "(errno %d, status %d)\n", fl->fl_pid,
638                                 status, ntohl(req->a_res.status));
639 
640         /*
641          * FIXME: This is a serious failure. We can
642          *
643          *  a.  Ignore the problem
644          *  b.  Send the owning process some signal (Linux doesn't have
645          *      SIGLOST, though...)
646          *  c.  Retry the operation
647          *
648          * Until someone comes up with a simple implementation
649          * for b or c, I'll choose option a.
650          */
651 
652         return -ENOLCK;
653 }
654 
655 /*
656  * UNLOCK: remove an existing lock
657  */
658 static int
659 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
660 {
661         struct nlm_host *host = req->a_host;
662         struct nlm_res  *resp = &req->a_res;
663         int status;
664         unsigned char fl_flags = fl->fl_flags;
665 
666         /*
667          * Note: the server is supposed to either grant us the unlock
668          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
669          * case, we want to unlock.
670          */
671         fl->fl_flags |= FL_EXISTS;
672         down_read(&host->h_rwsem);
673         status = do_vfs_lock(fl);
674         up_read(&host->h_rwsem);
675         fl->fl_flags = fl_flags;
676         if (status == -ENOENT) {
677                 status = 0;
678                 goto out;
679         }
680 
681         refcount_inc(&req->a_count);
682         status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
683                         NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
684         if (status < 0)
685                 goto out;
686 
687         if (resp->status == nlm_granted)
688                 goto out;
689 
690         if (resp->status != nlm_lck_denied_nolocks)
691                 printk("lockd: unexpected unlock status: %d\n",
692                         ntohl(resp->status));
693         /* What to do now? I'm out of my depth... */
694         status = -ENOLCK;
695 out:
696         nlmclnt_release_call(req);
697         return status;
698 }
699 
700 static void nlmclnt_unlock_prepare(struct rpc_task *task, void *data)
701 {
702         struct nlm_rqst *req = data;
703         const struct nlmclnt_operations *nlmclnt_ops = req->a_host->h_nlmclnt_ops;
704         bool defer_call = false;
705 
706         if (nlmclnt_ops && nlmclnt_ops->nlmclnt_unlock_prepare)
707                 defer_call = nlmclnt_ops->nlmclnt_unlock_prepare(task, req->a_callback_data);
708 
709         if (!defer_call)
710                 rpc_call_start(task);
711 }
712 
713 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
714 {
715         struct nlm_rqst *req = data;
716         u32 status = ntohl(req->a_res.status);
717 
718         if (RPC_ASSASSINATED(task))
719                 goto die;
720 
721         if (task->tk_status < 0) {
722                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
723                 switch (task->tk_status) {
724                 case -EACCES:
725                 case -EIO:
726                         goto die;
727                 default:
728                         goto retry_rebind;
729                 }
730         }
731         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
732                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
733                 goto retry_unlock;
734         }
735         if (status != NLM_LCK_GRANTED)
736                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
737 die:
738         return;
739  retry_rebind:
740         nlm_rebind_host(req->a_host);
741  retry_unlock:
742         rpc_restart_call(task);
743 }
744 
745 static const struct rpc_call_ops nlmclnt_unlock_ops = {
746         .rpc_call_prepare = nlmclnt_unlock_prepare,
747         .rpc_call_done = nlmclnt_unlock_callback,
748         .rpc_release = nlmclnt_rpc_release,
749 };
750 
751 /*
752  * Cancel a blocked lock request.
753  * We always use an async RPC call for this in order not to hang a
754  * process that has been Ctrl-C'ed.
755  */
756 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
757 {
758         struct nlm_rqst *req;
759         int status;
760 
761         dprintk("lockd: blocking lock attempt was interrupted by a signal.\n"
762                 "       Attempting to cancel lock.\n");
763 
764         req = nlm_alloc_call(host);
765         if (!req)
766                 return -ENOMEM;
767         req->a_flags = RPC_TASK_ASYNC;
768 
769         nlmclnt_setlockargs(req, fl);
770         req->a_args.block = block;
771 
772         refcount_inc(&req->a_count);
773         status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
774                         NLMPROC_CANCEL, &nlmclnt_cancel_ops);
775         if (status == 0 && req->a_res.status == nlm_lck_denied)
776                 status = -ENOLCK;
777         nlmclnt_release_call(req);
778         return status;
779 }
780 
781 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
782 {
783         struct nlm_rqst *req = data;
784         u32 status = ntohl(req->a_res.status);
785 
786         if (RPC_ASSASSINATED(task))
787                 goto die;
788 
789         if (task->tk_status < 0) {
790                 dprintk("lockd: CANCEL call error %d, retrying.\n",
791                                         task->tk_status);
792                 goto retry_cancel;
793         }
794 
795         dprintk("lockd: cancel status %u (task %u)\n",
796                         status, task->tk_pid);
797 
798         switch (status) {
799         case NLM_LCK_GRANTED:
800         case NLM_LCK_DENIED_GRACE_PERIOD:
801         case NLM_LCK_DENIED:
802                 /* Everything's good */
803                 break;
804         case NLM_LCK_DENIED_NOLOCKS:
805                 dprintk("lockd: CANCEL failed (server has no locks)\n");
806                 goto retry_cancel;
807         default:
808                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
809                         status);
810         }
811 
812 die:
813         return;
814 
815 retry_cancel:
816         /* Don't ever retry more than 3 times */
817         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
818                 goto die;
819         nlm_rebind_host(req->a_host);
820         rpc_restart_call(task);
821         rpc_delay(task, 30 * HZ);
822 }
823 
824 static const struct rpc_call_ops nlmclnt_cancel_ops = {
825         .rpc_call_done = nlmclnt_cancel_callback,
826         .rpc_release = nlmclnt_rpc_release,
827 };
828 
829 /*
830  * Convert an NLM status code to a generic kernel errno
831  */
832 static int
833 nlm_stat_to_errno(__be32 status)
834 {
835         switch(ntohl(status)) {
836         case NLM_LCK_GRANTED:
837                 return 0;
838         case NLM_LCK_DENIED:
839                 return -EAGAIN;
840         case NLM_LCK_DENIED_NOLOCKS:
841         case NLM_LCK_DENIED_GRACE_PERIOD:
842                 return -ENOLCK;
843         case NLM_LCK_BLOCKED:
844                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
845                 return -ENOLCK;
846 #ifdef CONFIG_LOCKD_V4
847         case NLM_DEADLCK:
848                 return -EDEADLK;
849         case NLM_ROFS:
850                 return -EROFS;
851         case NLM_STALE_FH:
852                 return -ESTALE;
853         case NLM_FBIG:
854                 return -EOVERFLOW;
855         case NLM_FAILED:
856                 return -ENOLCK;
857 #endif
858         }
859         printk(KERN_NOTICE "lockd: unexpected server status %d\n",
860                  ntohl(status));
861         return -ENOLCK;
862 }
863 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp