fs/lockd/clntproc.c

   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/types.h>
  11 #include <linux/errno.h>
  12 #include <linux/fs.h>
  13 #include <linux/nfs_fs.h>
  14 #include <linux/utsname.h>
  15 #include <linux/freezer.h>
  16 #include <linux/sunrpc/clnt.h>
  17 #include <linux/sunrpc/svc.h>
  18 #include <linux/lockd/lockd.h>
  19 #include <linux/lockd/sm_inter.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         atomic_inc(&lockowner->count);
  52         return lockowner;
  53 }
  54
  55 static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
  56 {
  57         if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
  58                 return;
  59         list_del(&lockowner->list);
  60         spin_unlock(&lockowner->host->h_lock);
  61         nlm_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                         atomic_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
 129         nlmclnt_next_cookie(&argp->cookie);
 130         argp->state   = nsm_local_state;
 131         memcpy(&lock->fh, NFS_FH(fl->fl_file->f_path.dentry->d_inode), sizeof(struct nfs_fh));
 132         lock->caller  = utsname()->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                                 utsname()->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         BUG_ON(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  *
 154  */
 155 int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl)
 156 {
 157         struct nlm_rqst         *call;
 158         sigset_t                oldset;
 159         unsigned long           flags;
 160         int                     status;
 161
 162         nlm_get_host(host);
 163         call = nlm_alloc_call(host);
 164         if (call == NULL)
 165                 return -ENOMEM;
 166
 167         nlmclnt_locks_init_private(fl, host);
 168         /* Set up the argument struct */
 169         nlmclnt_setlockargs(call, fl);
 170
 171         /* Keep the old signal mask */
 172         spin_lock_irqsave(&current->sighand->siglock, flags);
 173         oldset = current->blocked;
 174
 175         /* If we're cleaning up locks because the process is exiting,
 176          * perform the RPC call asynchronously. */
 177         if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
 178             && fl->fl_type == F_UNLCK
 179             && (current->flags & PF_EXITING)) {
 180                 sigfillset(&current->blocked);  /* Mask all signals */
 181                 recalc_sigpending();
 182
 183                 call->a_flags = RPC_TASK_ASYNC;
 184         }
 185         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 186
 187         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
 188                 if (fl->fl_type != F_UNLCK) {
 189                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
 190                         status = nlmclnt_lock(call, fl);
 191                 } else
 192                         status = nlmclnt_unlock(call, fl);
 193         } else if (IS_GETLK(cmd))
 194                 status = nlmclnt_test(call, fl);
 195         else
 196                 status = -EINVAL;
 197
 198         fl->fl_ops->fl_release_private(fl);
 199         fl->fl_ops = NULL;
 200
 201         spin_lock_irqsave(&current->sighand->siglock, flags);
 202         current->blocked = oldset;
 203         recalc_sigpending();
 204         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 205
 206         dprintk("lockd: clnt proc returns %d\n", status);
 207         return status;
 208 }
 209 EXPORT_SYMBOL_GPL(nlmclnt_proc);
 210
 211 /*
 212  * Allocate an NLM RPC call struct
 213  *
 214  * Note: the caller must hold a reference to host. In case of failure,
 215  * this reference will be released.
 216  */
 217 struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
 218 {
 219         struct nlm_rqst *call;
 220
 221         for(;;) {
 222                 call = kzalloc(sizeof(*call), GFP_KERNEL);
 223                 if (call != NULL) {
 224                         atomic_set(&call->a_count, 1);
 225                         locks_init_lock(&call->a_args.lock.fl);
 226                         locks_init_lock(&call->a_res.lock.fl);
 227                         call->a_host = host;
 228                         return call;
 229                 }
 230                 if (signalled())
 231                         break;
 232                 printk("nlm_alloc_call: failed, waiting for memory\n");
 233                 schedule_timeout_interruptible(5*HZ);
 234         }
 235         nlm_release_host(host);
 236         return NULL;
 237 }
 238
 239 void nlm_release_call(struct nlm_rqst *call)
 240 {
 241         if (!atomic_dec_and_test(&call->a_count))
 242                 return;
 243         nlm_release_host(call->a_host);
 244         nlmclnt_release_lockargs(call);
 245         kfree(call);
 246 }
 247
 248 static void nlmclnt_rpc_release(void *data)
 249 {
 250         nlm_release_call(data);
 251 }
 252
 253 static int nlm_wait_on_grace(wait_queue_head_t *queue)
 254 {
 255         DEFINE_WAIT(wait);
 256         int status = -EINTR;
 257
 258         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
 259         if (!signalled ()) {
 260                 schedule_timeout(NLMCLNT_GRACE_WAIT);
 261                 try_to_freeze();
 262                 if (!signalled ())
 263                         status = 0;
 264         }
 265         finish_wait(queue, &wait);
 266         return status;
 267 }
 268
 269 /*
 270  * Generic NLM call
 271  */
 272 static int
 273 nlmclnt_call(struct nlm_rqst *req, u32 proc)
 274 {
 275         struct nlm_host *host = req->a_host;
 276         struct rpc_clnt *clnt;
 277         struct nlm_args *argp = &req->a_args;
 278         struct nlm_res  *resp = &req->a_res;
 279         struct rpc_message msg = {
 280                 .rpc_argp       = argp,
 281                 .rpc_resp       = resp,
 282         };
 283         int             status;
 284
 285         dprintk("lockd: call procedure %d on %s\n",
 286                         (int)proc, host->h_name);
 287
 288         do {
 289                 if (host->h_reclaiming && !argp->reclaim)
 290                         goto in_grace_period;
 291
 292                 /* If we have no RPC client yet, create one. */
 293                 if ((clnt = nlm_bind_host(host)) == NULL)
 294                         return -ENOLCK;
 295                 msg.rpc_proc = &clnt->cl_procinfo[proc];
 296
 297                 /* Perform the RPC call. If an error occurs, try again */
 298                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
 299                         dprintk("lockd: rpc_call returned error %d\n", -status);
 300                         switch (status) {
 301                         case -EPROTONOSUPPORT:
 302                                 status = -EINVAL;
 303                                 break;
 304                         case -ECONNREFUSED:
 305                         case -ETIMEDOUT:
 306                         case -ENOTCONN:
 307                                 nlm_rebind_host(host);
 308                                 status = -EAGAIN;
 309                                 break;
 310                         case -ERESTARTSYS:
 311                                 return signalled () ? -EINTR : status;
 312                         default:
 313                                 break;
 314                         }
 315                         break;
 316                 } else
 317                 if (resp->status == nlm_lck_denied_grace_period) {
 318                         dprintk("lockd: server in grace period\n");
 319                         if (argp->reclaim) {
 320                                 printk(KERN_WARNING
 321                                      "lockd: spurious grace period reject?!\n");
 322                                 return -ENOLCK;
 323                         }
 324                 } else {
 325                         if (!argp->reclaim) {
 326                                 /* We appear to be out of the grace period */
 327                                 wake_up_all(&host->h_gracewait);
 328                         }
 329                         dprintk("lockd: server returns status %d\n", resp->status);
 330                         return 0;       /* Okay, call complete */
 331                 }
 332
 333 in_grace_period:
 334                 /*
 335                  * The server has rebooted and appears to be in the grace
 336                  * period during which locks are only allowed to be
 337                  * reclaimed.
 338                  * We can only back off and try again later.
 339                  */
 340                 status = nlm_wait_on_grace(&host->h_gracewait);
 341         } while (status == 0);
 342
 343         return status;
 344 }
 345
 346 /*
 347  * Generic NLM call, async version.
 348  */
 349 static struct rpc_task *__nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
 350 {
 351         struct nlm_host *host = req->a_host;
 352         struct rpc_clnt *clnt;
 353         struct rpc_task_setup task_setup_data = {
 354                 .rpc_message = msg,
 355                 .callback_ops = tk_ops,
 356                 .callback_data = req,
 357                 .flags = RPC_TASK_ASYNC,
 358         };
 359
 360         dprintk("lockd: call procedure %d on %s (async)\n",
 361                         (int)proc, host->h_name);
 362
 363         /* If we have no RPC client yet, create one. */
 364         clnt = nlm_bind_host(host);
 365         if (clnt == NULL)
 366                 goto out_err;
 367         msg->rpc_proc = &clnt->cl_procinfo[proc];
 368         task_setup_data.rpc_client = clnt;
 369
 370         /* bootstrap and kick off the async RPC call */
 371         return rpc_run_task(&task_setup_data);
 372 out_err:
 373         tk_ops->rpc_release(req);
 374         return ERR_PTR(-ENOLCK);
 375 }
 376
 377 static int nlm_do_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
 378 {
 379         struct rpc_task *task;
 380
 381         task = __nlm_async_call(req, proc, msg, tk_ops);
 382         if (IS_ERR(task))
 383                 return PTR_ERR(task);
 384         rpc_put_task(task);
 385         return 0;
 386 }
 387
 388 /*
 389  * NLM asynchronous call.
 390  */
 391 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 392 {
 393         struct rpc_message msg = {
 394                 .rpc_argp       = &req->a_args,
 395                 .rpc_resp       = &req->a_res,
 396         };
 397         return nlm_do_async_call(req, proc, &msg, tk_ops);
 398 }
 399
 400 int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 401 {
 402         struct rpc_message msg = {
 403                 .rpc_argp       = &req->a_res,
 404         };
 405         return nlm_do_async_call(req, proc, &msg, tk_ops);
 406 }
 407
 408 /*
 409  * NLM client asynchronous call.
 410  *
 411  * Note that although the calls are asynchronous, and are therefore
 412  *      guaranteed to complete, we still always attempt to wait for
 413  *      completion in order to be able to correctly track the lock
 414  *      state.
 415  */
 416 static int nlmclnt_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 417 {
 418         struct rpc_message msg = {
 419                 .rpc_argp       = &req->a_args,
 420                 .rpc_resp       = &req->a_res,
 421         };
 422         struct rpc_task *task;
 423         int err;
 424
 425         task = __nlm_async_call(req, proc, &msg, tk_ops);
 426         if (IS_ERR(task))
 427                 return PTR_ERR(task);
 428         err = rpc_wait_for_completion_task(task);
 429         rpc_put_task(task);
 430         return err;
 431 }
 432
 433 /*
 434  * TEST for the presence of a conflicting lock
 435  */
 436 static int
 437 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 438 {
 439         int     status;
 440
 441         status = nlmclnt_call(req, NLMPROC_TEST);
 442         if (status < 0)
 443                 goto out;
 444
 445         switch (req->a_res.status) {
 446                 case nlm_granted:
 447                         fl->fl_type = F_UNLCK;
 448                         break;
 449                 case nlm_lck_denied:
 450                         /*
 451                          * Report the conflicting lock back to the application.
 452                          */
 453                         fl->fl_start = req->a_res.lock.fl.fl_start;
 454                         fl->fl_end = req->a_res.lock.fl.fl_start;
 455                         fl->fl_type = req->a_res.lock.fl.fl_type;
 456                         fl->fl_pid = 0;
 457                         break;
 458                 default:
 459                         status = nlm_stat_to_errno(req->a_res.status);
 460         }
 461 out:
 462         nlm_release_call(req);
 463         return status;
 464 }
 465
 466 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 467 {
 468         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
 469         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
 470         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
 471 }
 472
 473 static void nlmclnt_locks_release_private(struct file_lock *fl)
 474 {
 475         list_del(&fl->fl_u.nfs_fl.list);
 476         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
 477 }
 478
 479 static struct file_lock_operations nlmclnt_lock_ops = {
 480         .fl_copy_lock = nlmclnt_locks_copy_lock,
 481         .fl_release_private = nlmclnt_locks_release_private,
 482 };
 483
 484 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 485 {
 486         BUG_ON(fl->fl_ops != NULL);
 487         fl->fl_u.nfs_fl.state = 0;
 488         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
 489         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
 490         fl->fl_ops = &nlmclnt_lock_ops;
 491 }
 492
 493 static int do_vfs_lock(struct file_lock *fl)
 494 {
 495         int res = 0;
 496         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
 497                 case FL_POSIX:
 498                         res = posix_lock_file_wait(fl->fl_file, fl);
 499                         break;
 500                 case FL_FLOCK:
 501                         res = flock_lock_file_wait(fl->fl_file, fl);
 502                         break;
 503                 default:
 504                         BUG();
 505         }
 506         return res;
 507 }
 508
 509 /*
 510  * LOCK: Try to create a lock
 511  *
 512  *                      Programmer Harassment Alert
 513  *
 514  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 515  * will faithfully return LCK_BLOCKED but never cares to notify us when
 516  * the lock could be granted. This way, our local process could hang
 517  * around forever waiting for the callback.
 518  *
 519  *  Solution A: Implement busy-waiting
 520  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 521  *
 522  * For now I am implementing solution A, because I hate the idea of
 523  * re-implementing lockd for a third time in two months. The async
 524  * calls shouldn't be too hard to do, however.
 525  *
 526  * This is one of the lovely things about standards in the NFS area:
 527  * they're so soft and squishy you can't really blame HP for doing this.
 528  */
 529 static int
 530 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 531 {
 532         struct nlm_host *host = req->a_host;
 533         struct nlm_res  *resp = &req->a_res;
 534         struct nlm_wait *block = NULL;
 535         unsigned char fl_flags = fl->fl_flags;
 536         int status = -ENOLCK;
 537
 538         if (nsm_monitor(host) < 0) {
 539                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
 540                                         host->h_name);
 541                 goto out;
 542         }
 543         fl->fl_flags |= FL_ACCESS;
 544         status = do_vfs_lock(fl);
 545         fl->fl_flags = fl_flags;
 546         if (status < 0)
 547                 goto out;
 548
 549         block = nlmclnt_prepare_block(host, fl);
 550 again:
 551         for(;;) {
 552                 /* Reboot protection */
 553                 fl->fl_u.nfs_fl.state = host->h_state;
 554                 status = nlmclnt_call(req, NLMPROC_LOCK);
 555                 if (status < 0)
 556                         goto out_unblock;
 557                 if (!req->a_args.block)
 558                         break;
 559                 /* Did a reclaimer thread notify us of a server reboot? */
 560                 if (resp->status ==  nlm_lck_denied_grace_period)
 561                         continue;
 562                 if (resp->status != nlm_lck_blocked)
 563                         break;
 564                 /* Wait on an NLM blocking lock */
 565                 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
 566                 /* if we were interrupted. Send a CANCEL request to the server
 567                  * and exit
 568                  */
 569                 if (status < 0)
 570                         goto out_unblock;
 571                 if (resp->status != nlm_lck_blocked)
 572                         break;
 573         }
 574
 575         if (resp->status == nlm_granted) {
 576                 down_read(&host->h_rwsem);
 577                 /* Check whether or not the server has rebooted */
 578                 if (fl->fl_u.nfs_fl.state != host->h_state) {
 579                         up_read(&host->h_rwsem);
 580                         goto again;
 581                 }
 582                 /* Ensure the resulting lock will get added to granted list */
 583                 fl->fl_flags |= FL_SLEEP;
 584                 if (do_vfs_lock(fl) < 0)
 585                         printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __FUNCTION__);
 586                 up_read(&host->h_rwsem);
 587                 fl->fl_flags = fl_flags;
 588         }
 589         status = nlm_stat_to_errno(resp->status);
 590 out_unblock:
 591         nlmclnt_finish_block(block);
 592         /* Cancel the blocked request if it is still pending */
 593         if (resp->status == nlm_lck_blocked)
 594                 nlmclnt_cancel(host, req->a_args.block, fl);
 595 out:
 596         nlm_release_call(req);
 597         return status;
 598 }
 599
 600 /*
 601  * RECLAIM: Try to reclaim a lock
 602  */
 603 int
 604 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 605 {
 606         struct nlm_rqst reqst, *req;
 607         int             status;
 608
 609         req = &reqst;
 610         memset(req, 0, sizeof(*req));
 611         locks_init_lock(&req->a_args.lock.fl);
 612         locks_init_lock(&req->a_res.lock.fl);
 613         req->a_host  = host;
 614         req->a_flags = 0;
 615
 616         /* Set up the argument struct */
 617         nlmclnt_setlockargs(req, fl);
 618         req->a_args.reclaim = 1;
 619
 620         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
 621          && req->a_res.status == nlm_granted)
 622                 return 0;
 623
 624         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 625                                 "(errno %d, status %d)\n", fl->fl_pid,
 626                                 status, ntohl(req->a_res.status));
 627
 628         /*
 629          * FIXME: This is a serious failure. We can
 630          *
 631          *  a.  Ignore the problem
 632          *  b.  Send the owning process some signal (Linux doesn't have
 633          *      SIGLOST, though...)
 634          *  c.  Retry the operation
 635          *
 636          * Until someone comes up with a simple implementation
 637          * for b or c, I'll choose option a.
 638          */
 639
 640         return -ENOLCK;
 641 }
 642
 643 /*
 644  * UNLOCK: remove an existing lock
 645  */
 646 static int
 647 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 648 {
 649         struct nlm_host *host = req->a_host;
 650         struct nlm_res  *resp = &req->a_res;
 651         int status;
 652         unsigned char fl_flags = fl->fl_flags;
 653
 654         /*
 655          * Note: the server is supposed to either grant us the unlock
 656          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
 657          * case, we want to unlock.
 658          */
 659         fl->fl_flags |= FL_EXISTS;
 660         down_read(&host->h_rwsem);
 661         status = do_vfs_lock(fl);
 662         up_read(&host->h_rwsem);
 663         fl->fl_flags = fl_flags;
 664         if (status == -ENOENT) {
 665                 status = 0;
 666                 goto out;
 667         }
 668
 669         atomic_inc(&req->a_count);
 670         status = nlmclnt_async_call(req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
 671         if (status < 0)
 672                 goto out;
 673
 674         if (resp->status == nlm_granted)
 675                 goto out;
 676
 677         if (resp->status != nlm_lck_denied_nolocks)
 678                 printk("lockd: unexpected unlock status: %d\n", resp->status);
 679         /* What to do now? I'm out of my depth... */
 680         status = -ENOLCK;
 681 out:
 682         nlm_release_call(req);
 683         return status;
 684 }
 685
 686 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
 687 {
 688         struct nlm_rqst *req = data;
 689         u32 status = ntohl(req->a_res.status);
 690
 691         if (RPC_ASSASSINATED(task))
 692                 goto die;
 693
 694         if (task->tk_status < 0) {
 695                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 696                 goto retry_rebind;
 697         }
 698         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 699                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 700                 goto retry_unlock;
 701         }
 702         if (status != NLM_LCK_GRANTED)
 703                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 704 die:
 705         return;
 706  retry_rebind:
 707         nlm_rebind_host(req->a_host);
 708  retry_unlock:
 709         rpc_restart_call(task);
 710 }
 711
 712 static const struct rpc_call_ops nlmclnt_unlock_ops = {
 713         .rpc_call_done = nlmclnt_unlock_callback,
 714         .rpc_release = nlmclnt_rpc_release,
 715 };
 716
 717 /*
 718  * Cancel a blocked lock request.
 719  * We always use an async RPC call for this in order not to hang a
 720  * process that has been Ctrl-C'ed.
 721  */
 722 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
 723 {
 724         struct nlm_rqst *req;
 725         unsigned long   flags;
 726         sigset_t        oldset;
 727         int             status;
 728
 729         /* Block all signals while setting up call */
 730         spin_lock_irqsave(&current->sighand->siglock, flags);
 731         oldset = current->blocked;
 732         sigfillset(&current->blocked);
 733         recalc_sigpending();
 734         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 735
 736         req = nlm_alloc_call(nlm_get_host(host));
 737         if (!req)
 738                 return -ENOMEM;
 739         req->a_flags = RPC_TASK_ASYNC;
 740
 741         nlmclnt_setlockargs(req, fl);
 742         req->a_args.block = block;
 743
 744         status = nlmclnt_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
 745
 746         spin_lock_irqsave(&current->sighand->siglock, flags);
 747         current->blocked = oldset;
 748         recalc_sigpending();
 749         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 750
 751         return status;
 752 }
 753
 754 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
 755 {
 756         struct nlm_rqst *req = data;
 757         u32 status = ntohl(req->a_res.status);
 758
 759         if (RPC_ASSASSINATED(task))
 760                 goto die;
 761
 762         if (task->tk_status < 0) {
 763                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 764                                         task->tk_status);
 765                 goto retry_cancel;
 766         }
 767
 768         dprintk("lockd: cancel status %u (task %u)\n",
 769                         status, task->tk_pid);
 770
 771         switch (status) {
 772         case NLM_LCK_GRANTED:
 773         case NLM_LCK_DENIED_GRACE_PERIOD:
 774         case NLM_LCK_DENIED:
 775                 /* Everything's good */
 776                 break;
 777         case NLM_LCK_DENIED_NOLOCKS:
 778                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 779                 goto retry_cancel;
 780         default:
 781                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 782                         status);
 783         }
 784
 785 die:
 786         return;
 787
 788 retry_cancel:
 789         /* Don't ever retry more than 3 times */
 790         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
 791                 goto die;
 792         nlm_rebind_host(req->a_host);
 793         rpc_restart_call(task);
 794         rpc_delay(task, 30 * HZ);
 795 }
 796
 797 static const struct rpc_call_ops nlmclnt_cancel_ops = {
 798         .rpc_call_done = nlmclnt_cancel_callback,
 799         .rpc_release = nlmclnt_rpc_release,
 800 };
 801
 802 /*
 803  * Convert an NLM status code to a generic kernel errno
 804  */
 805 static int
 806 nlm_stat_to_errno(__be32 status)
 807 {
 808         switch(ntohl(status)) {
 809         case NLM_LCK_GRANTED:
 810                 return 0;
 811         case NLM_LCK_DENIED:
 812                 return -EAGAIN;
 813         case NLM_LCK_DENIED_NOLOCKS:
 814         case NLM_LCK_DENIED_GRACE_PERIOD:
 815                 return -ENOLCK;
 816         case NLM_LCK_BLOCKED:
 817                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 818                 return -ENOLCK;
 819 #ifdef CONFIG_LOCKD_V4
 820         case NLM_DEADLCK:
 821                 return -EDEADLK;
 822         case NLM_ROFS:
 823                 return -EROFS;
 824         case NLM_STALE_FH:
 825                 return -ESTALE;
 826         case NLM_FBIG:
 827                 return -EOVERFLOW;
 828         case NLM_FAILED:
 829                 return -ENOLCK;
 830 #endif
 831         }
 832         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
 833         return -ENOLCK;
 834 }