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->c.flc_file)),
 137                sizeof(struct nfs_fh));
 138         lock->caller  = nodename;
 139         lock->oh.data = req->a_owner;
 140         lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
 141                                 (unsigned int)fl->fl_u.nfs_fl.owner->pid,
 142                                 nodename);
 143         lock->svid = fl->fl_u.nfs_fl.owner->pid;
 144         lock->fl.fl_start = fl->fl_start;
 145         lock->fl.fl_end = fl->fl_end;
 146         lock->fl.c.flc_type = fl->c.flc_type;
 147 }
 148
 149 static void nlmclnt_release_lockargs(struct nlm_rqst *req)
 150 {
 151         WARN_ON_ONCE(req->a_args.lock.fl.fl_ops != NULL);
 152 }
 153
 154 /**
 155  * nlmclnt_proc - Perform a single client-side lock request
 156  * @host: address of a valid nlm_host context representing the NLM server
 157  * @cmd: fcntl-style file lock operation to perform
 158  * @fl: address of arguments for the lock operation
 159  * @data: address of data to be sent to callback operations
 160  *
 161  */
 162 int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl, void *data)
 163 {
 164         struct nlm_rqst         *call;
 165         int                     status;
 166         const struct nlmclnt_operations *nlmclnt_ops = host->h_nlmclnt_ops;
 167
 168         call = nlm_alloc_call(host);
 169         if (call == NULL)
 170                 return -ENOMEM;
 171
 172         if (nlmclnt_ops && nlmclnt_ops->nlmclnt_alloc_call)
 173                 nlmclnt_ops->nlmclnt_alloc_call(data);
 174
 175         nlmclnt_locks_init_private(fl, host);
 176         if (!fl->fl_u.nfs_fl.owner) {
 177                 /* lockowner allocation has failed */
 178                 nlmclnt_release_call(call);
 179                 return -ENOMEM;
 180         }
 181         /* Set up the argument struct */
 182         nlmclnt_setlockargs(call, fl);
 183         call->a_callback_data = data;
 184
 185         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
 186                 if (fl->c.flc_type != F_UNLCK) {
 187                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
 188                         status = nlmclnt_lock(call, fl);
 189                 } else
 190                         status = nlmclnt_unlock(call, fl);
 191         } else if (IS_GETLK(cmd))
 192                 status = nlmclnt_test(call, fl);
 193         else
 194                 status = -EINVAL;
 195         fl->fl_ops->fl_release_private(fl);
 196         fl->fl_ops = NULL;
 197
 198         dprintk("lockd: clnt proc returns %d\n", status);
 199         return status;
 200 }
 201 EXPORT_SYMBOL_GPL(nlmclnt_proc);
 202
 203 /*
 204  * Allocate an NLM RPC call struct
 205  */
 206 struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
 207 {
 208         struct nlm_rqst *call;
 209
 210         for(;;) {
 211                 call = kzalloc(sizeof(*call), GFP_KERNEL);
 212                 if (call != NULL) {
 213                         refcount_set(&call->a_count, 1);
 214                         locks_init_lock(&call->a_args.lock.fl);
 215                         locks_init_lock(&call->a_res.lock.fl);
 216                         call->a_host = nlm_get_host(host);
 217                         return call;
 218                 }
 219                 if (signalled())
 220                         break;
 221                 printk("nlm_alloc_call: failed, waiting for memory\n");
 222                 schedule_timeout_interruptible(5*HZ);
 223         }
 224         return NULL;
 225 }
 226
 227 void nlmclnt_release_call(struct nlm_rqst *call)
 228 {
 229         const struct nlmclnt_operations *nlmclnt_ops = call->a_host->h_nlmclnt_ops;
 230
 231         if (!refcount_dec_and_test(&call->a_count))
 232                 return;
 233         if (nlmclnt_ops && nlmclnt_ops->nlmclnt_release_call)
 234                 nlmclnt_ops->nlmclnt_release_call(call->a_callback_data);
 235         nlmclnt_release_host(call->a_host);
 236         nlmclnt_release_lockargs(call);
 237         kfree(call);
 238 }
 239
 240 static void nlmclnt_rpc_release(void *data)
 241 {
 242         nlmclnt_release_call(data);
 243 }
 244
 245 static int nlm_wait_on_grace(wait_queue_head_t *queue)
 246 {
 247         DEFINE_WAIT(wait);
 248         int status = -EINTR;
 249
 250         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
 251         if (!signalled ()) {
 252                 schedule_timeout(NLMCLNT_GRACE_WAIT);
 253                 try_to_freeze();
 254                 if (!signalled ())
 255                         status = 0;
 256         }
 257         finish_wait(queue, &wait);
 258         return status;
 259 }
 260
 261 /*
 262  * Generic NLM call
 263  */
 264 static int
 265 nlmclnt_call(const struct cred *cred, struct nlm_rqst *req, u32 proc)
 266 {
 267         struct nlm_host *host = req->a_host;
 268         struct rpc_clnt *clnt;
 269         struct nlm_args *argp = &req->a_args;
 270         struct nlm_res  *resp = &req->a_res;
 271         struct rpc_message msg = {
 272                 .rpc_argp       = argp,
 273                 .rpc_resp       = resp,
 274                 .rpc_cred       = cred,
 275         };
 276         int             status;
 277
 278         dprintk("lockd: call procedure %d on %s\n",
 279                         (int)proc, host->h_name);
 280
 281         do {
 282                 if (host->h_reclaiming && !argp->reclaim)
 283                         goto in_grace_period;
 284
 285                 /* If we have no RPC client yet, create one. */
 286                 if ((clnt = nlm_bind_host(host)) == NULL)
 287                         return -ENOLCK;
 288                 msg.rpc_proc = &clnt->cl_procinfo[proc];
 289
 290                 /* Perform the RPC call. If an error occurs, try again */
 291                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
 292                         dprintk("lockd: rpc_call returned error %d\n", -status);
 293                         switch (status) {
 294                         case -EPROTONOSUPPORT:
 295                                 status = -EINVAL;
 296                                 break;
 297                         case -ECONNREFUSED:
 298                         case -ETIMEDOUT:
 299                         case -ENOTCONN:
 300                                 nlm_rebind_host(host);
 301                                 status = -EAGAIN;
 302                                 break;
 303                         case -ERESTARTSYS:
 304                                 return signalled () ? -EINTR : status;
 305                         default:
 306                                 break;
 307                         }
 308                         break;
 309                 } else
 310                 if (resp->status == nlm_lck_denied_grace_period) {
 311                         dprintk("lockd: server in grace period\n");
 312                         if (argp->reclaim) {
 313                                 printk(KERN_WARNING
 314                                      "lockd: spurious grace period reject?!\n");
 315                                 return -ENOLCK;
 316                         }
 317                 } else {
 318                         if (!argp->reclaim) {
 319                                 /* We appear to be out of the grace period */
 320                                 wake_up_all(&host->h_gracewait);
 321                         }
 322                         dprintk("lockd: server returns status %d\n",
 323                                 ntohl(resp->status));
 324                         return 0;       /* Okay, call complete */
 325                 }
 326
 327 in_grace_period:
 328                 /*
 329                  * The server has rebooted and appears to be in the grace
 330                  * period during which locks are only allowed to be
 331                  * reclaimed.
 332                  * We can only back off and try again later.
 333                  */
 334                 status = nlm_wait_on_grace(&host->h_gracewait);
 335         } while (status == 0);
 336
 337         return status;
 338 }
 339
 340 /*
 341  * Generic NLM call, async version.
 342  */
 343 static struct rpc_task *__nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
 344 {
 345         struct nlm_host *host = req->a_host;
 346         struct rpc_clnt *clnt;
 347         struct rpc_task_setup task_setup_data = {
 348                 .rpc_message = msg,
 349                 .callback_ops = tk_ops,
 350                 .callback_data = req,
 351                 .flags = RPC_TASK_ASYNC,
 352         };
 353
 354         dprintk("lockd: call procedure %d on %s (async)\n",
 355                         (int)proc, host->h_name);
 356
 357         /* If we have no RPC client yet, create one. */
 358         clnt = nlm_bind_host(host);
 359         if (clnt == NULL)
 360                 goto out_err;
 361         msg->rpc_proc = &clnt->cl_procinfo[proc];
 362         task_setup_data.rpc_client = clnt;
 363
 364         /* bootstrap and kick off the async RPC call */
 365         return rpc_run_task(&task_setup_data);
 366 out_err:
 367         tk_ops->rpc_release(req);
 368         return ERR_PTR(-ENOLCK);
 369 }
 370
 371 static int nlm_do_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
 372 {
 373         struct rpc_task *task;
 374
 375         task = __nlm_async_call(req, proc, msg, tk_ops);
 376         if (IS_ERR(task))
 377                 return PTR_ERR(task);
 378         rpc_put_task(task);
 379         return 0;
 380 }
 381
 382 /*
 383  * NLM asynchronous call.
 384  */
 385 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 386 {
 387         struct rpc_message msg = {
 388                 .rpc_argp       = &req->a_args,
 389                 .rpc_resp       = &req->a_res,
 390         };
 391         return nlm_do_async_call(req, proc, &msg, tk_ops);
 392 }
 393
 394 int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 395 {
 396         struct rpc_message msg = {
 397                 .rpc_argp       = &req->a_res,
 398         };
 399         return nlm_do_async_call(req, proc, &msg, tk_ops);
 400 }
 401
 402 /*
 403  * NLM client asynchronous call.
 404  *
 405  * Note that although the calls are asynchronous, and are therefore
 406  *      guaranteed to complete, we still always attempt to wait for
 407  *      completion in order to be able to correctly track the lock
 408  *      state.
 409  */
 410 static int nlmclnt_async_call(const struct cred *cred, struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
 411 {
 412         struct rpc_message msg = {
 413                 .rpc_argp       = &req->a_args,
 414                 .rpc_resp       = &req->a_res,
 415                 .rpc_cred       = cred,
 416         };
 417         struct rpc_task *task;
 418         int err;
 419
 420         task = __nlm_async_call(req, proc, &msg, tk_ops);
 421         if (IS_ERR(task))
 422                 return PTR_ERR(task);
 423         err = rpc_wait_for_completion_task(task);
 424         rpc_put_task(task);
 425         return err;
 426 }
 427
 428 /*
 429  * TEST for the presence of a conflicting lock
 430  */
 431 static int
 432 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
 433 {
 434         int     status;
 435
 436         status = nlmclnt_call(nfs_file_cred(fl->c.flc_file), req,
 437                               NLMPROC_TEST);
 438         if (status < 0)
 439                 goto out;
 440
 441         switch (req->a_res.status) {
 442                 case nlm_granted:
 443                         fl->c.flc_type = F_UNLCK;
 444                         break;
 445                 case nlm_lck_denied:
 446                         /*
 447                          * Report the conflicting lock back to the application.
 448                          */
 449                         fl->fl_start = req->a_res.lock.fl.fl_start;
 450                         fl->fl_end = req->a_res.lock.fl.fl_end;
 451                         fl->c.flc_type = req->a_res.lock.fl.c.flc_type;
 452                         fl->c.flc_pid = -req->a_res.lock.fl.c.flc_pid;
 453                         break;
 454                 default:
 455                         status = nlm_stat_to_errno(req->a_res.status);
 456         }
 457 out:
 458         trace_nlmclnt_test(&req->a_args.lock,
 459                            (const struct sockaddr *)&req->a_host->h_addr,
 460                            req->a_host->h_addrlen, req->a_res.status);
 461         nlmclnt_release_call(req);
 462         return status;
 463 }
 464
 465 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
 466 {
 467         spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
 468         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
 469         new->fl_u.nfs_fl.owner = nlmclnt_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         spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
 472 }
 473
 474 static void nlmclnt_locks_release_private(struct file_lock *fl)
 475 {
 476         spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
 477         list_del(&fl->fl_u.nfs_fl.list);
 478         spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
 479         nlmclnt_put_lockowner(fl->fl_u.nfs_fl.owner);
 480 }
 481
 482 static const struct file_lock_operations nlmclnt_lock_ops = {
 483         .fl_copy_lock = nlmclnt_locks_copy_lock,
 484         .fl_release_private = nlmclnt_locks_release_private,
 485 };
 486
 487 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 488 {
 489         fl->fl_u.nfs_fl.state = 0;
 490         fl->fl_u.nfs_fl.owner = nlmclnt_find_lockowner(host,
 491                                                        fl->c.flc_owner);
 492         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
 493         fl->fl_ops = &nlmclnt_lock_ops;
 494 }
 495
 496 static int do_vfs_lock(struct file_lock *fl)
 497 {
 498         return locks_lock_file_wait(fl->c.flc_file, fl);
 499 }
 500
 501 /*
 502  * LOCK: Try to create a lock
 503  *
 504  *                      Programmer Harassment Alert
 505  *
 506  * When given a blocking lock request in a sync RPC call, the HPUX lockd
 507  * will faithfully return LCK_BLOCKED but never cares to notify us when
 508  * the lock could be granted. This way, our local process could hang
 509  * around forever waiting for the callback.
 510  *
 511  *  Solution A: Implement busy-waiting
 512  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 513  *
 514  * For now I am implementing solution A, because I hate the idea of
 515  * re-implementing lockd for a third time in two months. The async
 516  * calls shouldn't be too hard to do, however.
 517  *
 518  * This is one of the lovely things about standards in the NFS area:
 519  * they're so soft and squishy you can't really blame HP for doing this.
 520  */
 521 static int
 522 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
 523 {
 524         const struct cred *cred = nfs_file_cred(fl->c.flc_file);
 525         struct nlm_host *host = req->a_host;
 526         struct nlm_res  *resp = &req->a_res;
 527         struct nlm_wait block;
 528         unsigned char flags = fl->c.flc_flags;
 529         unsigned char type;
 530         __be32 b_status;
 531         int status = -ENOLCK;
 532
 533         if (nsm_monitor(host) < 0)
 534                 goto out;
 535         req->a_args.state = nsm_local_state;
 536
 537         fl->c.flc_flags |= FL_ACCESS;
 538         status = do_vfs_lock(fl);
 539         fl->c.flc_flags = flags;
 540         if (status < 0)
 541                 goto out;
 542
 543         nlmclnt_prepare_block(&block, host, fl);
 544 again:
 545         /*
 546          * Initialise resp->status to a valid non-zero value,
 547          * since 0 == nlm_lck_granted
 548          */
 549         resp->status = nlm_lck_blocked;
 550
 551         /*
 552          * A GRANTED callback can come at any time -- even before the reply
 553          * to the LOCK request arrives, so we queue the wait before
 554          * requesting the lock.
 555          */
 556         nlmclnt_queue_block(&block);
 557         for (;;) {
 558                 /* Reboot protection */
 559                 fl->fl_u.nfs_fl.state = host->h_state;
 560                 status = nlmclnt_call(cred, req, NLMPROC_LOCK);
 561                 if (status < 0)
 562                         break;
 563                 /* Did a reclaimer thread notify us of a server reboot? */
 564                 if (resp->status == nlm_lck_denied_grace_period)
 565                         continue;
 566                 if (resp->status != nlm_lck_blocked)
 567                         break;
 568                 /* Wait on an NLM blocking lock */
 569                 status = nlmclnt_wait(&block, req, NLMCLNT_POLL_TIMEOUT);
 570                 if (status < 0)
 571                         break;
 572                 if (block.b_status != nlm_lck_blocked)
 573                         break;
 574         }
 575         b_status = nlmclnt_dequeue_block(&block);
 576         if (resp->status == nlm_lck_blocked)
 577                 resp->status = b_status;
 578
 579         /* if we were interrupted while blocking, then cancel the lock request
 580          * and exit
 581          */
 582         if (resp->status == nlm_lck_blocked) {
 583                 if (!req->a_args.block)
 584                         goto out_unlock;
 585                 if (nlmclnt_cancel(host, req->a_args.block, fl) == 0)
 586                         goto out;
 587         }
 588
 589         if (resp->status == nlm_granted) {
 590                 down_read(&host->h_rwsem);
 591                 /* Check whether or not the server has rebooted */
 592                 if (fl->fl_u.nfs_fl.state != host->h_state) {
 593                         up_read(&host->h_rwsem);
 594                         goto again;
 595                 }
 596                 /* Ensure the resulting lock will get added to granted list */
 597                 fl->c.flc_flags |= FL_SLEEP;
 598                 if (do_vfs_lock(fl) < 0)
 599                         printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __func__);
 600                 up_read(&host->h_rwsem);
 601                 fl->c.flc_flags = flags;
 602                 status = 0;
 603         }
 604         if (status < 0)
 605                 goto out_unlock;
 606         /*
 607          * EAGAIN doesn't make sense for sleeping locks, and in some
 608          * cases NLM_LCK_DENIED is returned for a permanent error.  So
 609          * turn it into an ENOLCK.
 610          */
 611         if (resp->status == nlm_lck_denied && (flags & FL_SLEEP))
 612                 status = -ENOLCK;
 613         else
 614                 status = nlm_stat_to_errno(resp->status);
 615 out:
 616         trace_nlmclnt_lock(&req->a_args.lock,
 617                            (const struct sockaddr *)&req->a_host->h_addr,
 618                            req->a_host->h_addrlen, req->a_res.status);
 619         nlmclnt_release_call(req);
 620         return status;
 621 out_unlock:
 622         /* Fatal error: ensure that we remove the lock altogether */
 623         trace_nlmclnt_lock(&req->a_args.lock,
 624                            (const struct sockaddr *)&req->a_host->h_addr,
 625                            req->a_host->h_addrlen, req->a_res.status);
 626         dprintk("lockd: lock attempt ended in fatal error.\n"
 627                 "       Attempting to unlock.\n");
 628         type = fl->c.flc_type;
 629         fl->c.flc_type = F_UNLCK;
 630         down_read(&host->h_rwsem);
 631         do_vfs_lock(fl);
 632         up_read(&host->h_rwsem);
 633         fl->c.flc_type = type;
 634         fl->c.flc_flags = flags;
 635         nlmclnt_async_call(cred, req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
 636         return status;
 637 }
 638
 639 /*
 640  * RECLAIM: Try to reclaim a lock
 641  */
 642 int
 643 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl,
 644                 struct nlm_rqst *req)
 645 {
 646         int             status;
 647
 648         memset(req, 0, sizeof(*req));
 649         locks_init_lock(&req->a_args.lock.fl);
 650         locks_init_lock(&req->a_res.lock.fl);
 651         req->a_host  = host;
 652
 653         /* Set up the argument struct */
 654         nlmclnt_setlockargs(req, fl);
 655         req->a_args.reclaim = 1;
 656
 657         status = nlmclnt_call(nfs_file_cred(fl->c.flc_file), req,
 658                               NLMPROC_LOCK);
 659         if (status >= 0 && req->a_res.status == nlm_granted)
 660                 return 0;
 661
 662         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
 663                                 "(errno %d, status %d)\n",
 664                                 fl->c.flc_pid,
 665                                 status, ntohl(req->a_res.status));
 666
 667         /*
 668          * FIXME: This is a serious failure. We can
 669          *
 670          *  a.  Ignore the problem
 671          *  b.  Send the owning process some signal (Linux doesn't have
 672          *      SIGLOST, though...)
 673          *  c.  Retry the operation
 674          *
 675          * Until someone comes up with a simple implementation
 676          * for b or c, I'll choose option a.
 677          */
 678
 679         return -ENOLCK;
 680 }
 681
 682 /*
 683  * UNLOCK: remove an existing lock
 684  */
 685 static int
 686 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
 687 {
 688         struct nlm_host *host = req->a_host;
 689         struct nlm_res  *resp = &req->a_res;
 690         int status;
 691         unsigned char flags = fl->c.flc_flags;
 692
 693         /*
 694          * Note: the server is supposed to either grant us the unlock
 695          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
 696          * case, we want to unlock.
 697          */
 698         fl->c.flc_flags |= FL_EXISTS;
 699         down_read(&host->h_rwsem);
 700         status = do_vfs_lock(fl);
 701         up_read(&host->h_rwsem);
 702         fl->c.flc_flags = flags;
 703         if (status == -ENOENT) {
 704                 status = 0;
 705                 goto out;
 706         }
 707
 708         refcount_inc(&req->a_count);
 709         status = nlmclnt_async_call(nfs_file_cred(fl->c.flc_file), req,
 710                                     NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
 711         if (status < 0)
 712                 goto out;
 713
 714         if (resp->status == nlm_granted)
 715                 goto out;
 716
 717         if (resp->status != nlm_lck_denied_nolocks)
 718                 printk("lockd: unexpected unlock status: %d\n",
 719                         ntohl(resp->status));
 720         /* What to do now? I'm out of my depth... */
 721         status = -ENOLCK;
 722 out:
 723         trace_nlmclnt_unlock(&req->a_args.lock,
 724                              (const struct sockaddr *)&req->a_host->h_addr,
 725                              req->a_host->h_addrlen, req->a_res.status);
 726         nlmclnt_release_call(req);
 727         return status;
 728 }
 729
 730 static void nlmclnt_unlock_prepare(struct rpc_task *task, void *data)
 731 {
 732         struct nlm_rqst *req = data;
 733         const struct nlmclnt_operations *nlmclnt_ops = req->a_host->h_nlmclnt_ops;
 734         bool defer_call = false;
 735
 736         if (nlmclnt_ops && nlmclnt_ops->nlmclnt_unlock_prepare)
 737                 defer_call = nlmclnt_ops->nlmclnt_unlock_prepare(task, req->a_callback_data);
 738
 739         if (!defer_call)
 740                 rpc_call_start(task);
 741 }
 742
 743 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
 744 {
 745         struct nlm_rqst *req = data;
 746         u32 status = ntohl(req->a_res.status);
 747
 748         if (RPC_SIGNALLED(task))
 749                 goto die;
 750
 751         if (task->tk_status < 0) {
 752                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
 753                 switch (task->tk_status) {
 754                 case -EACCES:
 755                 case -EIO:
 756                         goto die;
 757                 default:
 758                         goto retry_rebind;
 759                 }
 760         }
 761         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
 762                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
 763                 goto retry_unlock;
 764         }
 765         if (status != NLM_LCK_GRANTED)
 766                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
 767 die:
 768         return;
 769  retry_rebind:
 770         nlm_rebind_host(req->a_host);
 771  retry_unlock:
 772         rpc_restart_call(task);
 773 }
 774
 775 static const struct rpc_call_ops nlmclnt_unlock_ops = {
 776         .rpc_call_prepare = nlmclnt_unlock_prepare,
 777         .rpc_call_done = nlmclnt_unlock_callback,
 778         .rpc_release = nlmclnt_rpc_release,
 779 };
 780
 781 /*
 782  * Cancel a blocked lock request.
 783  * We always use an async RPC call for this in order not to hang a
 784  * process that has been Ctrl-C'ed.
 785  */
 786 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
 787 {
 788         struct nlm_rqst *req;
 789         int status;
 790
 791         dprintk("lockd: blocking lock attempt was interrupted by a signal.\n"
 792                 "       Attempting to cancel lock.\n");
 793
 794         req = nlm_alloc_call(host);
 795         if (!req)
 796                 return -ENOMEM;
 797         req->a_flags = RPC_TASK_ASYNC;
 798
 799         nlmclnt_setlockargs(req, fl);
 800         req->a_args.block = block;
 801
 802         refcount_inc(&req->a_count);
 803         status = nlmclnt_async_call(nfs_file_cred(fl->c.flc_file), req,
 804                                     NLMPROC_CANCEL, &nlmclnt_cancel_ops);
 805         if (status == 0 && req->a_res.status == nlm_lck_denied)
 806                 status = -ENOLCK;
 807         nlmclnt_release_call(req);
 808         return status;
 809 }
 810
 811 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
 812 {
 813         struct nlm_rqst *req = data;
 814         u32 status = ntohl(req->a_res.status);
 815
 816         if (RPC_SIGNALLED(task))
 817                 goto die;
 818
 819         if (task->tk_status < 0) {
 820                 dprintk("lockd: CANCEL call error %d, retrying.\n",
 821                                         task->tk_status);
 822                 goto retry_cancel;
 823         }
 824
 825         switch (status) {
 826         case NLM_LCK_GRANTED:
 827         case NLM_LCK_DENIED_GRACE_PERIOD:
 828         case NLM_LCK_DENIED:
 829                 /* Everything's good */
 830                 break;
 831         case NLM_LCK_DENIED_NOLOCKS:
 832                 dprintk("lockd: CANCEL failed (server has no locks)\n");
 833                 goto retry_cancel;
 834         default:
 835                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
 836                         status);
 837         }
 838
 839 die:
 840         return;
 841
 842 retry_cancel:
 843         /* Don't ever retry more than 3 times */
 844         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
 845                 goto die;
 846         nlm_rebind_host(req->a_host);
 847         rpc_restart_call(task);
 848         rpc_delay(task, 30 * HZ);
 849 }
 850
 851 static const struct rpc_call_ops nlmclnt_cancel_ops = {
 852         .rpc_call_done = nlmclnt_cancel_callback,
 853         .rpc_release = nlmclnt_rpc_release,
 854 };
 855
 856 /*
 857  * Convert an NLM status code to a generic kernel errno
 858  */
 859 static int
 860 nlm_stat_to_errno(__be32 status)
 861 {
 862         switch(ntohl(status)) {
 863         case NLM_LCK_GRANTED:
 864                 return 0;
 865         case NLM_LCK_DENIED:
 866                 return -EAGAIN;
 867         case NLM_LCK_DENIED_NOLOCKS:
 868         case NLM_LCK_DENIED_GRACE_PERIOD:
 869                 return -ENOLCK;
 870         case NLM_LCK_BLOCKED:
 871                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
 872                 return -ENOLCK;
 873 #ifdef CONFIG_LOCKD_V4
 874         case NLM_DEADLCK:
 875                 return -EDEADLK;
 876         case NLM_ROFS:
 877                 return -EROFS;
 878         case NLM_STALE_FH:
 879                 return -ESTALE;
 880         case NLM_FBIG:
 881                 return -EOVERFLOW;
 882         case NLM_FAILED:
 883                 return -ENOLCK;
 884 #endif
 885         }
 886         printk(KERN_NOTICE "lockd: unexpected server status %d\n",
 887                  ntohl(status));
 888         return -ENOLCK;
 889 }