fs/lockd/clntproc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * linux/fs/lockd/clntproc.c
   4  *
   5  * RPC procedures for the client side NLM implementation
   6  *
   7  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/slab.h>
  12 #include <linux/types.h>
  13 #include <linux/errno.h>
  14 #include <linux/fs.h>
  15 #include <linux/filelock.h>
  16 #include <linux/nfs_fs.h>
  17 #include <linux/utsname.h>
  18 #include <linux/freezer.h>
  19 #include <linux/sunrpc/clnt.h>
  20 #include <linux/sunrpc/svc.h>
  21 #include <linux/lockd/lockd.h>
  22
  23 #include "trace.h"
  24
  25 #define NLMDBG_FACILITY         NLMDBG_CLIENT
  26 #define NLMCLNT_GRACE_WAIT      (5*HZ)
  27 #define NLMCLNT_POLL_TIMEOUT    (30*HZ)
  28 #define NLMCLNT_MAX_RETRIES     3
  29
  30 static int      nlmclnt_test(struct nlm_rqst *, struct file_lock *);
  31 static int      nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
  32 static int      nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
  33 static int      nlm_stat_to_errno(__be32 stat);
  34 static void     nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
  35 static int      nlmclnt_cancel(struct nlm_host *, int , struct file_lock *);
  36
  37 static const struct rpc_call_ops nlmclnt_unlock_ops;
  38 static const struct rpc_call_ops nlmclnt_cancel_ops;
  39
  40 /*
  41  * Cookie counter for NLM requests
  42  */
  43 static atomic_t nlm_cookie = ATOMIC_INIT(0x1234);
  44
  45 void nlmclnt_next_cookie(struct nlm_cookie *c)
  46 {
  47         u32     cookie = atomic_inc_return(&nlm_cookie);
  48
  49         memcpy(c->data, &cookie, 4);
  50         c->len=4;
  51 }
  52
  53 static struct nlm_lockowner *
  54 nlmclnt_get_lockowner(struct nlm_lockowner *lockowner)
  55 {
  56         refcount_inc(&lockowner->count);
  57         return lockowner;
  58 }
  59
  60 static void nlmclnt_put_lockowner(struct nlm_lockowner *lockowner)
  61 {
  62         if (!refcount_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
  63                 return;
  64         list_del(&lockowner->list);
  65         spin_unlock(&lockowner->host->h_lock);
  66         nlmclnt_release_host(lockowner->host);
  67         kfree(lockowner);
  68 }
  69
  70 static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
  71 {
  72         struct nlm_lockowner *lockowner;
  73         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  74                 if (lockowner->pid == pid)
  75                         return -EBUSY;
  76         }
  77         return 0;
  78 }
  79
  80 static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
  81 {
  82         uint32_t res;
  83         do {
  84                 res = host->h_pidcount++;
  85         } while (nlm_pidbusy(host, res) < 0);
  86         return res;
  87 }
  88
  89 static struct nlm_lockowner *__nlmclnt_find_lockowner(struct nlm_host *host, fl_owner_t owner)
  90 {
  91         struct nlm_lockowner *lockowner;
  92         list_for_each_entry(lockowner, &host->h_lockowners, list) {
  93                 if (lockowner->owner != owner)
  94                         continue;
  95                 return nlmclnt_get_lockowner(lockowner);
  96         }
  97         return NULL;
  98 }
  99
 100 static struct nlm_lockowner *nlmclnt_find_lockowner(struct nlm_host *host, fl_owner_t owner)
 101 {
 102         struct nlm_lockowner *res, *new = NULL;
 103
 104         spin_lock(&host->h_lock);
 105         res = __nlmclnt_find_lockowner(host, owner);
 106         if (res == NULL) {
 107                 spin_unlock(&host->h_lock);
 108                 new = kmalloc(sizeof(*new), GFP_KERNEL);
 109                 spin_lock(&host->h_lock);
 110                 res = __nlmclnt_find_lockowner(host, owner);
 111                 if (res == NULL && new != NULL) {
 112                         res = new;
 113                         refcount_set(&new->count, 1);
 114                         new->owner = owner;
 115                         new->pid = __nlm_alloc_pid(host);
 116                         new->host = nlm_get_host(host);
 117                         list_add(&new->list, &host->h_lockowners);
 118                         new = NULL;
 119                 }
 120         }
 121         spin_unlock(&host->h_lock);
 122         kfree(new);
 123         return res;
 124 }
 125
 126 /*
 127  * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
 128  */
 129 static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
 130 {
 131         struct nlm_args *argp = &req->a_args;
 132         struct nlm_lock *lock = &argp->lock;
 133         char *nodename = req->a_host->h_rpcclnt->cl_nodename;
 134
 135         nlmclnt_next_cookie(&argp->cookie);
 136         memcpy(&lock->fh, NFS_FH(file_inode(fl->fl_file)), sizeof(struct nfs_fh));
 137         lock->caller  = nodename;
 138         lock->oh.data = req->a_owner;
 139         lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
 140                                 (unsigned int)fl->fl_u.nfs_fl.owner->pid,
 141                                 nodename);
 142         lock->svid = fl->fl_u.nfs_fl.owner->pid;
 143         lock->fl.fl_start = fl->fl_start;
 144         lock->fl.fl_end = fl->fl_end;
 145         lock->fl.fl_type = fl->fl_type;
 146 }
 147
 148 static void nlmclnt_release_lockargs(struct nlm_rqst *req)
 149 {
 150         WARN_ON_ONCE(req->a_args.lock.fl.fl_ops != NULL);
 151 }
 152
 153 /**
 154  * nlmclnt_proc - Perform a single client-side lock request
 155  * @host: address of a valid nlm_host context representing the NLM server
 156  * @cmd: fcntl-style file lock operation to perform
 157  * @fl: address of arguments for the lock operation
 158  * @data: address of data to be sent to callback operations
 159  *
 160  */
 161 int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl, void *data)
 162 {
 163         struct nlm_rqst         *call;
 164         int                     status;
 165         const struct nlmclnt_operations *nlmclnt_ops = host->h_nlmclnt_ops;
 166
 167         call = nlm_alloc_call(host);
 168         if (call == NULL)
 169                 return -ENOMEM;
 170
 171         if (nlmclnt_ops && nlmclnt_ops->nlmclnt_alloc_call)
 172                 nlmclnt_ops->nlmclnt_alloc_call(data);
 173
 174         nlmclnt_locks_init_private(fl, host);
 175         if (!fl->fl_u.nfs_fl.owner) {
 176                 /* lockowner allocation has failed */
 177                 nlmclnt_release_call(call);
 178                 return -ENOMEM;
 179         }
 180         /* Set up the argument struct */
 181         nlmclnt_setlockargs(call, fl);
 182         call->a_callback_data = data;
 183
 184         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
 185                 if (fl->fl_type != F_UNLCK) {
 186                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
 187                         status = nlmclnt_lock(call, fl);
 188                 } else
 189                         status = nlmclnt_unlock(call, fl);
 190         } else if (IS_GETLK(cmd))
 191                 status = nlmclnt_test(call, fl);
 192         else
 193                 status = -EINVAL;
 194         fl->fl_ops->fl_release_private(fl);
 195         fl->fl_ops = NULL;
 196
 197         dprintk("lockd: clnt proc returns %d\n", status);
 198         return status;
 199 }
 200 EXPORT_SYMBOL_GPL(nlmclnt_proc);
 201
 202 /*
 203  * Allocate an NLM RPC call struct
 204  */
 205 struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
 206 {
 207         struct nlm_rqst *call;
 208
 209         for(;;) {
 210                 call = kzalloc(sizeof(*call), GFP_KERNEL);
 211                 if (call != NULL) {
 212                         refcount_set(&call->a_count, 1);
 213                         locks_init_lock(&call->a_args.lock.fl);
 214                         locks_init_lock(&call->a_res.lock.fl);
 215                         call->a_host = nlm_get_host(host);
 216                         return call;
 217                 }
 218                 if (signalled())
 219                         break;
 220                 printk("nlm_alloc_call: failed, waiting for memory\n");
 221                 schedule_timeout_interruptible(5*HZ);
 222         }
 223         return NULL;
 224 }
 225
 226 void nlmclnt_release_call(struct nlm_rqst *call)
 227 {
 228         const struct nlmclnt_operations *nlmclnt_ops = call->a_host->h_nlmclnt_ops;
 229
 230         if (!refcount_dec_and_test(&call->a_count))
 231                 return;
 232         if (nlmclnt_ops && nlmclnt_ops->nlmclnt_release_call)
 233                 nlmclnt_ops->nlmclnt_release_call(call->a_callback_data);
 234         nlmclnt_release_host(call->a_host);
 235         nlmclnt_release_lockargs(call);
 236         kfree(call);
 237 }
 238
 239 static void nlmclnt_rpc_release(void *data)
 240 {
 241         nlmclnt_release_call(data);
 242 }
 243
 244 static int nlm_wait_on_grace(wait_queue_head_t *queue)
 245 {
 246         DEFINE_WAIT(wait);
 247         int status = -EINTR;
 248
 249         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
 250         if (!signalled ()) {
 251                 schedule_timeout(NLMCLNT_GRACE_WAIT);
 252                 try_to_freeze();
 253                 if (!signalled ())
 254                         status = 0;
 255         }
 256         finish_wait(queue, &wait);
 257         return status;
 258 }
 259
 260 /*
 261  * Generic NLM call
 262  */
 263 static int
 264 nlmclnt_call(const struct cred *cred, struct nlm_rqst *req, u32 proc)
 265 {
 266         struct nlm_host *host = req->a_host;
 267         struct rpc_clnt *clnt;
 268         struct nlm_args *argp = &req->a_args;
 269         struct nlm_res  *resp = &req->a_res;
 270         struct rpc_message msg = {
 271                 .rpc_argp       = argp,
 272                 .rpc_resp       = resp,
 273                 .rpc_cred       = cred,
 274         };
 275         int             status;
 276
 277         dprintk("lockd: call procedure %d on %s\n",
 278                         (int)proc, host->h_name);
 279
 280         do {
 281                 if (host->h_reclaiming && !argp->reclaim)
 282                         goto in_grace_period;
 283
 284                 /* If we have no RPC client yet, create one. */
 285                 if ((clnt = nlm_bind_host(host)) == NULL)
 286                         return -ENOLCK;
 287                 msg.rpc_proc = &clnt->cl_procinfo[proc];
 288
 289                 /* Perform the RPC call. If an error occurs, try again */
 290                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
 291                         dprintk("lockd: rpc_call returned error %d\n", -status);
 292                         switch (status) {
 293                         case -EPROTONOSUPPORT:
 294                                 status = -EINVAL;
 295                                 break;
 296                         case -ECONNREFUSED:
 297                         case -ETIMEDOUT:
 298                         case -ENOTCONN:
 299                                 nlm_rebind_host(host);
 300                                 status = -EAGAIN;
 301                                 break;
 302                         case -ERESTARTSYS:
 303                                 return signalled () ? -EINTR : status;
 304                         default:
 305                                 break;
 306                         }
 307                         break;
 308                 } else
 309                 if (resp->status == nlm_lck_denied_grace_period) {
 310                         dprintk("lockd: server in grace period\n");
 311                         if (argp->reclaim) {
 312                                 printk(KERN_WARNING
 313                                      "lockd: spurious grace period reject?!\n");
 314                                 return -ENOLCK;
 315                         }
 316                 } else {
 317                         if (!argp->reclaim) {
 318                                 /* We appear to be out of the grace period */
 319                                 wake_up_all(&host->h_gracewait);
 320                         }
 321                         dprintk("lockd: server returns status %d\n",
 322                                 ntohl(resp->status));
 323                         return 0;       /* Okay, call complete */
 324                 }
 325
 326 in_grace_period:
 327                 /*
 328                  * The server has rebooted and appears to be in the grace
 329                  * period during which locks are only allowed to be
 330                  * reclaimed.
 331                  * We can only back off and try again later.
 332                  */
 333                 status = nlm_wait_on_grace(&host->h_gracewait);
 334         } while (status == 0);
 335
 336         return status;
 337 }
 338
 339 /*
 340  * Generic NLM call, async version.
 341  */
 342 static struct rpc_task *__nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
 343 {
 344         struct nlm_host *host = req->a_host;
 345         struct rpc_clnt *clnt;
 346         struct rpc_task_setup task_setup_data = {
 347                 .rpc_message = msg,
 348                 .callback_ops = tk_ops,
 349                 .callback_data = req,
 350                 .flags = RPC_TASK_ASYNC,
 351         };
 352
 353         dprintk("lockd: call procedure %d on %s (async)\n",
 354                         (int)proc, host->h_name);
 355
 356         /* If we have no RPC client yet, create one. */
 357         clnt = nlm_bind_host(host);
 358         if (clnt == NULL)
 359                 goto out_err;
 360         msg->rpc_proc = &clnt->cl_procinfo[proc];
 361         task_setup_data.rpc_client = clnt;
 362
 363         /* bootstrap and kick off the async RPC call */
 364         return rpc_run_task(&task_setup_data);
 365 out_err:
 366         tk_ops->rpc_release(req);
 367         return ERR_PTR(-ENOLCK);
 368 }
 369
 370 static int nlm_do_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
 371 {
 372         struct rpc_task *task;
 373
 374         task = __nlm_async_call(req, proc, msg, tk_ops);
 375         if (IS_ERR(task))
 376                 return PTR_ERR(task);
 377         rpc_put_task(task);
 378         return 0;
 379 }
 380
 381 /*
 382  * NLM asynchronous call.
 383  */
 384 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 385 {
 386         struct rpc_message msg = {
 387                 .rpc_argp       = &req->a_args,
 388                 .rpc_resp       = &req->a_res,
 389         };
 390         return nlm_do_async_call(req, proc, &msg, tk_ops);
 391 }
 392
 393 int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 394 {
 395         struct rpc_message msg = {
 396                 .rpc_argp       = &req->a_res,
 397         };
 398         return nlm_do_async_call(req, proc, &msg, tk_ops);
 399 }
 400
 401 /*
 402  * NLM client asynchronous call.
 403  *
 404  * Note that although the calls are asynchronous, and are therefore
 405  *      guaranteed to complete, we still always attempt to wait for
 406  *      completion in order to be able to correctly track the lock
 407  *      state.
 408  */
 409 static int nlmclnt_async_call(const struct cred *cred, struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 410 {
 411         struct rpc_message msg = {
 412                 .rpc_argp       = &req->a_args,
 413                 .rpc_resp       = &req->a_res,
 414                 .rpc_cred       = cred,
 415         };
 416         struct rpc_task *task;
 417         int err;
 418
 419         task = __nlm_async_call(req, proc, &msg, tk_ops);
 420         if (IS_ERR(task))
 421                 return PTR_ERR(task);
 422         err = rpc_wait_for_completion_task(task);
 423         rpc_put_task(task);
 424         return err;
 425 }
 426
 427 /*
 428  * TEST for the presence of a conflicting lock
 429  */
 430 static int
 431 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 432 {
 433         int     status;
 434
 435         status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_TEST);
 436         if (status < 0)
 437                 goto out;
 438
 439         switch (req->a_res.status) {
 440                 case nlm_granted:
 441                         fl->fl_type = F_UNLCK;
 442                         break;
 443                 case nlm_lck_denied:
 444                         /*
 445                          * Report the conflicting lock back to the application.
 446                          */
 447                         fl->fl_start = req->a_res.lock.fl.fl_start;
 448                         fl->fl_end = req->a_res.lock.fl.fl_end;
 449                         fl->fl_type = req->a_res.lock.fl.fl_type;
 450                         fl->fl_pid = -req->a_res.lock.fl.fl_pid;
 451                         break;
 452                 default:
 453                         status = nlm_stat_to_errno(req->a_res.status);
 454         }
 455 out:
 456         trace_nlmclnt_test(&req->a_args.lock,
 457                            (const struct sockaddr *)&req->a_host->h_addr,
 458                            req->a_host->h_addrlen, req->a_res.status);
 459         nlmclnt_release_call(req);
 460         return status;
 461 }
 462
 463 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 464 {
 465         spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
 466         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
 467         new->fl_u.nfs_fl.owner = nlmclnt_get_lockowner(fl->fl_u.nfs_fl.owner);
 468         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
 469         spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
 470 }
 471
 472 static void nlmclnt_locks_release_private(struct file_lock *fl)
 473 {
 474         spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
 475         list_del(&fl->fl_u.nfs_fl.list);
 476         spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
 477         nlmclnt_put_lockowner(fl->fl_u.nfs_fl.owner);
 478 }
 479
 480 static const struct file_lock_operations nlmclnt_lock_ops = {
 481         .fl_copy_lock = nlmclnt_locks_copy_lock,
 482         .fl_release_private = nlmclnt_locks_release_private,
 483 };
 484
 485 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 486 {
 487         fl->fl_u.nfs_fl.state = 0;
 488         fl->fl_u.nfs_fl.owner = nlmclnt_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         return locks_lock_file_wait(fl->fl_file, fl);
 496 }
 497
 498 /*
 499  * LOCK: Try to create a lock
 500  *
 501  *                      Programmer Harassment Alert
 502  *
 503  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 504  * will faithfully return LCK_BLOCKED but never cares to notify us when
 505  * the lock could be granted. This way, our local process could hang
 506  * around forever waiting for the callback.
 507  *
 508  *  Solution A: Implement busy-waiting
 509  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 510  *
 511  * For now I am implementing solution A, because I hate the idea of
 512  * re-implementing lockd for a third time in two months. The async
 513  * calls shouldn't be too hard to do, however.
 514  *
 515  * This is one of the lovely things about standards in the NFS area:
 516  * they're so soft and squishy you can't really blame HP for doing this.
 517  */
 518 static int
 519 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 520 {
 521         const struct cred *cred = nfs_file_cred(fl->fl_file);
 522         struct nlm_host *host = req->a_host;
 523         struct nlm_res  *resp = &req->a_res;
 524         struct nlm_wait block;
 525         unsigned char fl_flags = fl->fl_flags;
 526         unsigned char fl_type;
 527         __be32 b_status;
 528         int status = -ENOLCK;
 529
 530         if (nsm_monitor(host) < 0)
 531                 goto out;
 532         req->a_args.state = nsm_local_state;
 533
 534         fl->fl_flags |= FL_ACCESS;
 535         status = do_vfs_lock(fl);
 536         fl->fl_flags = fl_flags;
 537         if (status < 0)
 538                 goto out;
 539
 540         nlmclnt_prepare_block(&block, host, fl);
 541 again:
 542         /*
 543          * Initialise resp->status to a valid non-zero value,
 544          * since 0 == nlm_lck_granted
 545          */
 546         resp->status = nlm_lck_blocked;
 547
 548         /*
 549          * A GRANTED callback can come at any time -- even before the reply
 550          * to the LOCK request arrives, so we queue the wait before
 551          * requesting the lock.
 552          */
 553         nlmclnt_queue_block(&block);
 554         for (;;) {
 555                 /* Reboot protection */
 556                 fl->fl_u.nfs_fl.state = host->h_state;
 557                 status = nlmclnt_call(cred, req, NLMPROC_LOCK);
 558                 if (status < 0)
 559                         break;
 560                 /* Did a reclaimer thread notify us of a server reboot? */
 561                 if (resp->status == nlm_lck_denied_grace_period)
 562                         continue;
 563                 if (resp->status != nlm_lck_blocked)
 564                         break;
 565                 /* Wait on an NLM blocking lock */
 566                 status = nlmclnt_wait(&block, req, NLMCLNT_POLL_TIMEOUT);
 567                 if (status < 0)
 568                         break;
 569                 if (block.b_status != nlm_lck_blocked)
 570                         break;
 571         }
 572         b_status = nlmclnt_dequeue_block(&block);
 573         if (resp->status == nlm_lck_blocked)
 574                 resp->status = b_status;
 575
 576         /* if we were interrupted while blocking, then cancel the lock request
 577          * and exit
 578          */
 579         if (resp->status == nlm_lck_blocked) {
 580                 if (!req->a_args.block)
 581                         goto out_unlock;
 582                 if (nlmclnt_cancel(host, req->a_args.block, fl) == 0)
 583                         goto out;
 584         }
 585
 586         if (resp->status == nlm_granted) {
 587                 down_read(&host->h_rwsem);
 588                 /* Check whether or not the server has rebooted */
 589                 if (fl->fl_u.nfs_fl.state != host->h_state) {
 590                         up_read(&host->h_rwsem);
 591                         goto again;
 592                 }
 593                 /* Ensure the resulting lock will get added to granted list */
 594                 fl->fl_flags |= FL_SLEEP;
 595                 if (do_vfs_lock(fl) < 0)
 596                         printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __func__);
 597                 up_read(&host->h_rwsem);
 598                 fl->fl_flags = fl_flags;
 599                 status = 0;
 600         }
 601         if (status < 0)
 602                 goto out_unlock;
 603         /*
 604          * EAGAIN doesn't make sense for sleeping locks, and in some
 605          * cases NLM_LCK_DENIED is returned for a permanent error.  So
 606          * turn it into an ENOLCK.
 607          */
 608         if (resp->status == nlm_lck_denied && (fl_flags & FL_SLEEP))
 609                 status = -ENOLCK;
 610         else
 611                 status = nlm_stat_to_errno(resp->status);
 612 out:
 613         trace_nlmclnt_lock(&req->a_args.lock,
 614                            (const struct sockaddr *)&req->a_host->h_addr,
 615                            req->a_host->h_addrlen, req->a_res.status);
 616         nlmclnt_release_call(req);
 617         return status;
 618 out_unlock:
 619         /* Fatal error: ensure that we remove the lock altogether */
 620         trace_nlmclnt_lock(&req->a_args.lock,
 621                            (const struct sockaddr *)&req->a_host->h_addr,
 622                            req->a_host->h_addrlen, req->a_res.status);
 623         dprintk("lockd: lock attempt ended in fatal error.\n"
 624                 "       Attempting to unlock.\n");
 625         fl_type = fl->fl_type;
 626         fl->fl_type = F_UNLCK;
 627         down_read(&host->h_rwsem);
 628         do_vfs_lock(fl);
 629         up_read(&host->h_rwsem);
 630         fl->fl_type = fl_type;
 631         fl->fl_flags = fl_flags;
 632         nlmclnt_async_call(cred, req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
 633         return status;
 634 }
 635
 636 /*
 637  * RECLAIM: Try to reclaim a lock
 638  */
 639 int
 640 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl,
 641                 struct nlm_rqst *req)
 642 {
 643         int             status;
 644
 645         memset(req, 0, sizeof(*req));
 646         locks_init_lock(&req->a_args.lock.fl);
 647         locks_init_lock(&req->a_res.lock.fl);
 648         req->a_host  = host;
 649
 650         /* Set up the argument struct */
 651         nlmclnt_setlockargs(req, fl);
 652         req->a_args.reclaim = 1;
 653
 654         status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_LOCK);
 655         if (status >= 0 && req->a_res.status == nlm_granted)
 656                 return 0;
 657
 658         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 659                                 "(errno %d, status %d)\n", fl->fl_pid,
 660                                 status, ntohl(req->a_res.status));
 661
 662         /*
 663          * FIXME: This is a serious failure. We can
 664          *
 665          *  a.  Ignore the problem
 666          *  b.  Send the owning process some signal (Linux doesn't have
 667          *      SIGLOST, though...)
 668          *  c.  Retry the operation
 669          *
 670          * Until someone comes up with a simple implementation
 671          * for b or c, I'll choose option a.
 672          */
 673
 674         return -ENOLCK;
 675 }
 676
 677 /*
 678  * UNLOCK: remove an existing lock
 679  */
 680 static int
 681 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 682 {
 683         struct nlm_host *host = req->a_host;
 684         struct nlm_res  *resp = &req->a_res;
 685         int status;
 686         unsigned char fl_flags = fl->fl_flags;
 687
 688         /*
 689          * Note: the server is supposed to either grant us the unlock
 690          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
 691          * case, we want to unlock.
 692          */
 693         fl->fl_flags |= FL_EXISTS;
 694         down_read(&host->h_rwsem);
 695         status = do_vfs_lock(fl);
 696         up_read(&host->h_rwsem);
 697         fl->fl_flags = fl_flags;
 698         if (status == -ENOENT) {
 699                 status = 0;
 700                 goto out;
 701         }
 702
 703         refcount_inc(&req->a_count);
 704         status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
 705                         NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
 706         if (status < 0)
 707                 goto out;
 708
 709         if (resp->status == nlm_granted)
 710                 goto out;
 711
 712         if (resp->status != nlm_lck_denied_nolocks)
 713                 printk("lockd: unexpected unlock status: %d\n",
 714                         ntohl(resp->status));
 715         /* What to do now? I'm out of my depth... */
 716         status = -ENOLCK;
 717 out:
 718         trace_nlmclnt_unlock(&req->a_args.lock,
 719                              (const struct sockaddr *)&req->a_host->h_addr,
 720                              req->a_host->h_addrlen, req->a_res.status);
 721         nlmclnt_release_call(req);
 722         return status;
 723 }
 724
 725 static void nlmclnt_unlock_prepare(struct rpc_task *task, void *data)
 726 {
 727         struct nlm_rqst *req = data;
 728         const struct nlmclnt_operations *nlmclnt_ops = req->a_host->h_nlmclnt_ops;
 729         bool defer_call = false;
 730
 731         if (nlmclnt_ops && nlmclnt_ops->nlmclnt_unlock_prepare)
 732                 defer_call = nlmclnt_ops->nlmclnt_unlock_prepare(task, req->a_callback_data);
 733
 734         if (!defer_call)
 735                 rpc_call_start(task);
 736 }
 737
 738 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
 739 {
 740         struct nlm_rqst *req = data;
 741         u32 status = ntohl(req->a_res.status);
 742
 743         if (RPC_SIGNALLED(task))
 744                 goto die;
 745
 746         if (task->tk_status < 0) {
 747                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 748                 switch (task->tk_status) {
 749                 case -EACCES:
 750                 case -EIO:
 751                         goto die;
 752                 default:
 753                         goto retry_rebind;
 754                 }
 755         }
 756         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 757                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 758                 goto retry_unlock;
 759         }
 760         if (status != NLM_LCK_GRANTED)
 761                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 762 die:
 763         return;
 764  retry_rebind:
 765         nlm_rebind_host(req->a_host);
 766  retry_unlock:
 767         rpc_restart_call(task);
 768 }
 769
 770 static const struct rpc_call_ops nlmclnt_unlock_ops = {
 771         .rpc_call_prepare = nlmclnt_unlock_prepare,
 772         .rpc_call_done = nlmclnt_unlock_callback,
 773         .rpc_release = nlmclnt_rpc_release,
 774 };
 775
 776 /*
 777  * Cancel a blocked lock request.
 778  * We always use an async RPC call for this in order not to hang a
 779  * process that has been Ctrl-C'ed.
 780  */
 781 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
 782 {
 783         struct nlm_rqst *req;
 784         int status;
 785
 786         dprintk("lockd: blocking lock attempt was interrupted by a signal.\n"
 787                 "       Attempting to cancel lock.\n");
 788
 789         req = nlm_alloc_call(host);
 790         if (!req)
 791                 return -ENOMEM;
 792         req->a_flags = RPC_TASK_ASYNC;
 793
 794         nlmclnt_setlockargs(req, fl);
 795         req->a_args.block = block;
 796
 797         refcount_inc(&req->a_count);
 798         status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
 799                         NLMPROC_CANCEL, &nlmclnt_cancel_ops);
 800         if (status == 0 && req->a_res.status == nlm_lck_denied)
 801                 status = -ENOLCK;
 802         nlmclnt_release_call(req);
 803         return status;
 804 }
 805
 806 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
 807 {
 808         struct nlm_rqst *req = data;
 809         u32 status = ntohl(req->a_res.status);
 810
 811         if (RPC_SIGNALLED(task))
 812                 goto die;
 813
 814         if (task->tk_status < 0) {
 815                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 816                                         task->tk_status);
 817                 goto retry_cancel;
 818         }
 819
 820         switch (status) {
 821         case NLM_LCK_GRANTED:
 822         case NLM_LCK_DENIED_GRACE_PERIOD:
 823         case NLM_LCK_DENIED:
 824                 /* Everything's good */
 825                 break;
 826         case NLM_LCK_DENIED_NOLOCKS:
 827                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 828                 goto retry_cancel;
 829         default:
 830                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 831                         status);
 832         }
 833
 834 die:
 835         return;
 836
 837 retry_cancel:
 838         /* Don't ever retry more than 3 times */
 839         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
 840                 goto die;
 841         nlm_rebind_host(req->a_host);
 842         rpc_restart_call(task);
 843         rpc_delay(task, 30 * HZ);
 844 }
 845
 846 static const struct rpc_call_ops nlmclnt_cancel_ops = {
 847         .rpc_call_done = nlmclnt_cancel_callback,
 848         .rpc_release = nlmclnt_rpc_release,
 849 };
 850
 851 /*
 852  * Convert an NLM status code to a generic kernel errno
 853  */
 854 static int
 855 nlm_stat_to_errno(__be32 status)
 856 {
 857         switch(ntohl(status)) {
 858         case NLM_LCK_GRANTED:
 859                 return 0;
 860         case NLM_LCK_DENIED:
 861                 return -EAGAIN;
 862         case NLM_LCK_DENIED_NOLOCKS:
 863         case NLM_LCK_DENIED_GRACE_PERIOD:
 864                 return -ENOLCK;
 865         case NLM_LCK_BLOCKED:
 866                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 867                 return -ENOLCK;
 868 #ifdef CONFIG_LOCKD_V4
 869         case NLM_DEADLCK:
 870                 return -EDEADLK;
 871         case NLM_ROFS:
 872                 return -EROFS;
 873         case NLM_STALE_FH:
 874                 return -ESTALE;
 875         case NLM_FBIG:
 876                 return -EOVERFLOW;
 877         case NLM_FAILED:
 878                 return -ENOLCK;
 879 #endif
 880         }
 881         printk(KERN_NOTICE "lockd: unexpected server status %d\n",
 882                  ntohl(status));
 883         return -ENOLCK;
 884 }