Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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/config.h> |
| 10 | #include <linux/module.h> |
| 11 | #include <linux/types.h> |
| 12 | #include <linux/errno.h> |
| 13 | #include <linux/fs.h> |
| 14 | #include <linux/nfs_fs.h> |
| 15 | #include <linux/utsname.h> |
| 16 | #include <linux/smp_lock.h> |
| 17 | #include <linux/sunrpc/clnt.h> |
| 18 | #include <linux/sunrpc/svc.h> |
| 19 | #include <linux/lockd/lockd.h> |
| 20 | #include <linux/lockd/sm_inter.h> |
| 21 | |
| 22 | #define NLMDBG_FACILITY NLMDBG_CLIENT |
| 23 | #define NLMCLNT_GRACE_WAIT (5*HZ) |
| 24 | |
| 25 | static int nlmclnt_test(struct nlm_rqst *, struct file_lock *); |
| 26 | static int nlmclnt_lock(struct nlm_rqst *, struct file_lock *); |
| 27 | static int nlmclnt_unlock(struct nlm_rqst *, struct file_lock *); |
| 28 | static void nlmclnt_unlock_callback(struct rpc_task *); |
| 29 | static void nlmclnt_cancel_callback(struct rpc_task *); |
| 30 | static int nlm_stat_to_errno(u32 stat); |
| 31 | static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host); |
| 32 | |
| 33 | /* |
| 34 | * Cookie counter for NLM requests |
| 35 | */ |
| 36 | static u32 nlm_cookie = 0x1234; |
| 37 | |
| 38 | static inline void nlmclnt_next_cookie(struct nlm_cookie *c) |
| 39 | { |
| 40 | memcpy(c->data, &nlm_cookie, 4); |
| 41 | memset(c->data+4, 0, 4); |
| 42 | c->len=4; |
| 43 | nlm_cookie++; |
| 44 | } |
| 45 | |
| 46 | static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner) |
| 47 | { |
| 48 | atomic_inc(&lockowner->count); |
| 49 | return lockowner; |
| 50 | } |
| 51 | |
| 52 | static void nlm_put_lockowner(struct nlm_lockowner *lockowner) |
| 53 | { |
| 54 | if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock)) |
| 55 | return; |
| 56 | list_del(&lockowner->list); |
| 57 | spin_unlock(&lockowner->host->h_lock); |
| 58 | nlm_release_host(lockowner->host); |
| 59 | kfree(lockowner); |
| 60 | } |
| 61 | |
| 62 | static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid) |
| 63 | { |
| 64 | struct nlm_lockowner *lockowner; |
| 65 | list_for_each_entry(lockowner, &host->h_lockowners, list) { |
| 66 | if (lockowner->pid == pid) |
| 67 | return -EBUSY; |
| 68 | } |
| 69 | return 0; |
| 70 | } |
| 71 | |
| 72 | static inline uint32_t __nlm_alloc_pid(struct nlm_host *host) |
| 73 | { |
| 74 | uint32_t res; |
| 75 | do { |
| 76 | res = host->h_pidcount++; |
| 77 | } while (nlm_pidbusy(host, res) < 0); |
| 78 | return res; |
| 79 | } |
| 80 | |
| 81 | static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner) |
| 82 | { |
| 83 | struct nlm_lockowner *lockowner; |
| 84 | list_for_each_entry(lockowner, &host->h_lockowners, list) { |
| 85 | if (lockowner->owner != owner) |
| 86 | continue; |
| 87 | return nlm_get_lockowner(lockowner); |
| 88 | } |
| 89 | return NULL; |
| 90 | } |
| 91 | |
| 92 | static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner) |
| 93 | { |
| 94 | struct nlm_lockowner *res, *new = NULL; |
| 95 | |
| 96 | spin_lock(&host->h_lock); |
| 97 | res = __nlm_find_lockowner(host, owner); |
| 98 | if (res == NULL) { |
| 99 | spin_unlock(&host->h_lock); |
| 100 | new = (struct nlm_lockowner *)kmalloc(sizeof(*new), GFP_KERNEL); |
| 101 | spin_lock(&host->h_lock); |
| 102 | res = __nlm_find_lockowner(host, owner); |
| 103 | if (res == NULL && new != NULL) { |
| 104 | res = new; |
| 105 | atomic_set(&new->count, 1); |
| 106 | new->owner = owner; |
| 107 | new->pid = __nlm_alloc_pid(host); |
| 108 | new->host = nlm_get_host(host); |
| 109 | list_add(&new->list, &host->h_lockowners); |
| 110 | new = NULL; |
| 111 | } |
| 112 | } |
| 113 | spin_unlock(&host->h_lock); |
| 114 | if (new != NULL) |
| 115 | kfree(new); |
| 116 | return res; |
| 117 | } |
| 118 | |
| 119 | /* |
| 120 | * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls |
| 121 | */ |
| 122 | static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl) |
| 123 | { |
| 124 | struct nlm_args *argp = &req->a_args; |
| 125 | struct nlm_lock *lock = &argp->lock; |
| 126 | |
| 127 | nlmclnt_next_cookie(&argp->cookie); |
| 128 | argp->state = nsm_local_state; |
| 129 | memcpy(&lock->fh, NFS_FH(fl->fl_file->f_dentry->d_inode), sizeof(struct nfs_fh)); |
| 130 | lock->caller = system_utsname.nodename; |
| 131 | lock->oh.data = req->a_owner; |
| 132 | lock->oh.len = sprintf(req->a_owner, "%d@%s", |
| 133 | current->pid, system_utsname.nodename); |
| 134 | locks_copy_lock(&lock->fl, fl); |
| 135 | } |
| 136 | |
| 137 | static void nlmclnt_release_lockargs(struct nlm_rqst *req) |
| 138 | { |
| 139 | struct file_lock *fl = &req->a_args.lock.fl; |
| 140 | |
| 141 | if (fl->fl_ops && fl->fl_ops->fl_release_private) |
| 142 | fl->fl_ops->fl_release_private(fl); |
| 143 | } |
| 144 | |
| 145 | /* |
| 146 | * Initialize arguments for GRANTED call. The nlm_rqst structure |
| 147 | * has been cleared already. |
| 148 | */ |
| 149 | int |
| 150 | nlmclnt_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock) |
| 151 | { |
| 152 | locks_copy_lock(&call->a_args.lock.fl, &lock->fl); |
| 153 | memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh)); |
| 154 | call->a_args.lock.caller = system_utsname.nodename; |
| 155 | call->a_args.lock.oh.len = lock->oh.len; |
| 156 | |
| 157 | /* set default data area */ |
| 158 | call->a_args.lock.oh.data = call->a_owner; |
| 159 | |
| 160 | if (lock->oh.len > NLMCLNT_OHSIZE) { |
| 161 | void *data = kmalloc(lock->oh.len, GFP_KERNEL); |
| 162 | if (!data) { |
| 163 | nlmclnt_freegrantargs(call); |
| 164 | return 0; |
| 165 | } |
| 166 | call->a_args.lock.oh.data = (u8 *) data; |
| 167 | } |
| 168 | |
| 169 | memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len); |
| 170 | return 1; |
| 171 | } |
| 172 | |
| 173 | void |
| 174 | nlmclnt_freegrantargs(struct nlm_rqst *call) |
| 175 | { |
| 176 | struct file_lock *fl = &call->a_args.lock.fl; |
| 177 | /* |
| 178 | * Check whether we allocated memory for the owner. |
| 179 | */ |
| 180 | if (call->a_args.lock.oh.data != (u8 *) call->a_owner) { |
| 181 | kfree(call->a_args.lock.oh.data); |
| 182 | } |
| 183 | if (fl->fl_ops && fl->fl_ops->fl_release_private) |
| 184 | fl->fl_ops->fl_release_private(fl); |
| 185 | } |
| 186 | |
| 187 | /* |
| 188 | * This is the main entry point for the NLM client. |
| 189 | */ |
| 190 | int |
| 191 | nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl) |
| 192 | { |
| 193 | struct nfs_server *nfssrv = NFS_SERVER(inode); |
| 194 | struct nlm_host *host; |
| 195 | struct nlm_rqst reqst, *call = &reqst; |
| 196 | sigset_t oldset; |
| 197 | unsigned long flags; |
| 198 | int status, proto, vers; |
| 199 | |
| 200 | vers = (NFS_PROTO(inode)->version == 3) ? 4 : 1; |
| 201 | if (NFS_PROTO(inode)->version > 3) { |
| 202 | printk(KERN_NOTICE "NFSv4 file locking not implemented!\n"); |
| 203 | return -ENOLCK; |
| 204 | } |
| 205 | |
| 206 | /* Retrieve transport protocol from NFS client */ |
| 207 | proto = NFS_CLIENT(inode)->cl_xprt->prot; |
| 208 | |
| 209 | if (!(host = nlmclnt_lookup_host(NFS_ADDR(inode), proto, vers))) |
| 210 | return -ENOLCK; |
| 211 | |
| 212 | /* Create RPC client handle if not there, and copy soft |
| 213 | * and intr flags from NFS client. */ |
| 214 | if (host->h_rpcclnt == NULL) { |
| 215 | struct rpc_clnt *clnt; |
| 216 | |
| 217 | /* Bind an rpc client to this host handle (does not |
| 218 | * perform a portmapper lookup) */ |
| 219 | if (!(clnt = nlm_bind_host(host))) { |
| 220 | status = -ENOLCK; |
| 221 | goto done; |
| 222 | } |
| 223 | clnt->cl_softrtry = nfssrv->client->cl_softrtry; |
| 224 | clnt->cl_intr = nfssrv->client->cl_intr; |
| 225 | clnt->cl_chatty = nfssrv->client->cl_chatty; |
| 226 | } |
| 227 | |
| 228 | /* Keep the old signal mask */ |
| 229 | spin_lock_irqsave(¤t->sighand->siglock, flags); |
| 230 | oldset = current->blocked; |
| 231 | |
| 232 | /* If we're cleaning up locks because the process is exiting, |
| 233 | * perform the RPC call asynchronously. */ |
| 234 | if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) |
| 235 | && fl->fl_type == F_UNLCK |
| 236 | && (current->flags & PF_EXITING)) { |
| 237 | sigfillset(¤t->blocked); /* Mask all signals */ |
| 238 | recalc_sigpending(); |
| 239 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); |
| 240 | |
| 241 | call = nlmclnt_alloc_call(); |
| 242 | if (!call) { |
| 243 | status = -ENOMEM; |
| 244 | goto out_restore; |
| 245 | } |
| 246 | call->a_flags = RPC_TASK_ASYNC; |
| 247 | } else { |
| 248 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); |
| 249 | memset(call, 0, sizeof(*call)); |
| 250 | locks_init_lock(&call->a_args.lock.fl); |
| 251 | locks_init_lock(&call->a_res.lock.fl); |
| 252 | } |
| 253 | call->a_host = host; |
| 254 | |
| 255 | nlmclnt_locks_init_private(fl, host); |
| 256 | |
| 257 | /* Set up the argument struct */ |
| 258 | nlmclnt_setlockargs(call, fl); |
| 259 | |
| 260 | if (IS_SETLK(cmd) || IS_SETLKW(cmd)) { |
| 261 | if (fl->fl_type != F_UNLCK) { |
| 262 | call->a_args.block = IS_SETLKW(cmd) ? 1 : 0; |
| 263 | status = nlmclnt_lock(call, fl); |
| 264 | } else |
| 265 | status = nlmclnt_unlock(call, fl); |
| 266 | } else if (IS_GETLK(cmd)) |
| 267 | status = nlmclnt_test(call, fl); |
| 268 | else |
| 269 | status = -EINVAL; |
| 270 | |
| 271 | out_restore: |
| 272 | spin_lock_irqsave(¤t->sighand->siglock, flags); |
| 273 | current->blocked = oldset; |
| 274 | recalc_sigpending(); |
| 275 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); |
| 276 | |
| 277 | done: |
| 278 | dprintk("lockd: clnt proc returns %d\n", status); |
| 279 | nlm_release_host(host); |
| 280 | return status; |
| 281 | } |
| 282 | EXPORT_SYMBOL(nlmclnt_proc); |
| 283 | |
| 284 | /* |
| 285 | * Allocate an NLM RPC call struct |
| 286 | */ |
| 287 | struct nlm_rqst * |
| 288 | nlmclnt_alloc_call(void) |
| 289 | { |
| 290 | struct nlm_rqst *call; |
| 291 | |
| 292 | while (!signalled()) { |
| 293 | call = (struct nlm_rqst *) kmalloc(sizeof(struct nlm_rqst), GFP_KERNEL); |
| 294 | if (call) { |
| 295 | memset(call, 0, sizeof(*call)); |
| 296 | locks_init_lock(&call->a_args.lock.fl); |
| 297 | locks_init_lock(&call->a_res.lock.fl); |
| 298 | return call; |
| 299 | } |
| 300 | printk("nlmclnt_alloc_call: failed, waiting for memory\n"); |
| 301 | current->state = TASK_INTERRUPTIBLE; |
| 302 | schedule_timeout(5*HZ); |
| 303 | } |
| 304 | return NULL; |
| 305 | } |
| 306 | |
| 307 | static int nlm_wait_on_grace(wait_queue_head_t *queue) |
| 308 | { |
| 309 | DEFINE_WAIT(wait); |
| 310 | int status = -EINTR; |
| 311 | |
| 312 | prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE); |
| 313 | if (!signalled ()) { |
| 314 | schedule_timeout(NLMCLNT_GRACE_WAIT); |
| 315 | try_to_freeze(PF_FREEZE); |
| 316 | if (!signalled ()) |
| 317 | status = 0; |
| 318 | } |
| 319 | finish_wait(queue, &wait); |
| 320 | return status; |
| 321 | } |
| 322 | |
| 323 | /* |
| 324 | * Generic NLM call |
| 325 | */ |
| 326 | static int |
| 327 | nlmclnt_call(struct nlm_rqst *req, u32 proc) |
| 328 | { |
| 329 | struct nlm_host *host = req->a_host; |
| 330 | struct rpc_clnt *clnt; |
| 331 | struct nlm_args *argp = &req->a_args; |
| 332 | struct nlm_res *resp = &req->a_res; |
| 333 | struct rpc_message msg = { |
| 334 | .rpc_argp = argp, |
| 335 | .rpc_resp = resp, |
| 336 | }; |
| 337 | int status; |
| 338 | |
| 339 | dprintk("lockd: call procedure %d on %s\n", |
| 340 | (int)proc, host->h_name); |
| 341 | |
| 342 | do { |
| 343 | if (host->h_reclaiming && !argp->reclaim) |
| 344 | goto in_grace_period; |
| 345 | |
| 346 | /* If we have no RPC client yet, create one. */ |
| 347 | if ((clnt = nlm_bind_host(host)) == NULL) |
| 348 | return -ENOLCK; |
| 349 | msg.rpc_proc = &clnt->cl_procinfo[proc]; |
| 350 | |
| 351 | /* Perform the RPC call. If an error occurs, try again */ |
| 352 | if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) { |
| 353 | dprintk("lockd: rpc_call returned error %d\n", -status); |
| 354 | switch (status) { |
| 355 | case -EPROTONOSUPPORT: |
| 356 | status = -EINVAL; |
| 357 | break; |
| 358 | case -ECONNREFUSED: |
| 359 | case -ETIMEDOUT: |
| 360 | case -ENOTCONN: |
| 361 | nlm_rebind_host(host); |
| 362 | status = -EAGAIN; |
| 363 | break; |
| 364 | case -ERESTARTSYS: |
| 365 | return signalled () ? -EINTR : status; |
| 366 | default: |
| 367 | break; |
| 368 | } |
| 369 | break; |
| 370 | } else |
| 371 | if (resp->status == NLM_LCK_DENIED_GRACE_PERIOD) { |
| 372 | dprintk("lockd: server in grace period\n"); |
| 373 | if (argp->reclaim) { |
| 374 | printk(KERN_WARNING |
| 375 | "lockd: spurious grace period reject?!\n"); |
| 376 | return -ENOLCK; |
| 377 | } |
| 378 | } else { |
| 379 | if (!argp->reclaim) { |
| 380 | /* We appear to be out of the grace period */ |
| 381 | wake_up_all(&host->h_gracewait); |
| 382 | } |
| 383 | dprintk("lockd: server returns status %d\n", resp->status); |
| 384 | return 0; /* Okay, call complete */ |
| 385 | } |
| 386 | |
| 387 | in_grace_period: |
| 388 | /* |
| 389 | * The server has rebooted and appears to be in the grace |
| 390 | * period during which locks are only allowed to be |
| 391 | * reclaimed. |
| 392 | * We can only back off and try again later. |
| 393 | */ |
| 394 | status = nlm_wait_on_grace(&host->h_gracewait); |
| 395 | } while (status == 0); |
| 396 | |
| 397 | return status; |
| 398 | } |
| 399 | |
| 400 | /* |
| 401 | * Generic NLM call, async version. |
| 402 | */ |
| 403 | int |
| 404 | nlmsvc_async_call(struct nlm_rqst *req, u32 proc, rpc_action callback) |
| 405 | { |
| 406 | struct nlm_host *host = req->a_host; |
| 407 | struct rpc_clnt *clnt; |
| 408 | struct rpc_message msg = { |
| 409 | .rpc_argp = &req->a_args, |
| 410 | .rpc_resp = &req->a_res, |
| 411 | }; |
| 412 | int status; |
| 413 | |
| 414 | dprintk("lockd: call procedure %d on %s (async)\n", |
| 415 | (int)proc, host->h_name); |
| 416 | |
| 417 | /* If we have no RPC client yet, create one. */ |
| 418 | if ((clnt = nlm_bind_host(host)) == NULL) |
| 419 | return -ENOLCK; |
| 420 | msg.rpc_proc = &clnt->cl_procinfo[proc]; |
| 421 | |
| 422 | /* bootstrap and kick off the async RPC call */ |
| 423 | status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, callback, req); |
| 424 | |
| 425 | return status; |
| 426 | } |
| 427 | |
| 428 | static int |
| 429 | nlmclnt_async_call(struct nlm_rqst *req, u32 proc, rpc_action callback) |
| 430 | { |
| 431 | struct nlm_host *host = req->a_host; |
| 432 | struct rpc_clnt *clnt; |
| 433 | struct nlm_args *argp = &req->a_args; |
| 434 | struct nlm_res *resp = &req->a_res; |
| 435 | struct rpc_message msg = { |
| 436 | .rpc_argp = argp, |
| 437 | .rpc_resp = resp, |
| 438 | }; |
| 439 | int status; |
| 440 | |
| 441 | dprintk("lockd: call procedure %d on %s (async)\n", |
| 442 | (int)proc, host->h_name); |
| 443 | |
| 444 | /* If we have no RPC client yet, create one. */ |
| 445 | if ((clnt = nlm_bind_host(host)) == NULL) |
| 446 | return -ENOLCK; |
| 447 | msg.rpc_proc = &clnt->cl_procinfo[proc]; |
| 448 | |
| 449 | /* Increment host refcount */ |
| 450 | nlm_get_host(host); |
| 451 | /* bootstrap and kick off the async RPC call */ |
| 452 | status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, callback, req); |
| 453 | if (status < 0) |
| 454 | nlm_release_host(host); |
| 455 | return status; |
| 456 | } |
| 457 | |
| 458 | /* |
| 459 | * TEST for the presence of a conflicting lock |
| 460 | */ |
| 461 | static int |
| 462 | nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl) |
| 463 | { |
| 464 | int status; |
| 465 | |
| 466 | status = nlmclnt_call(req, NLMPROC_TEST); |
| 467 | nlmclnt_release_lockargs(req); |
| 468 | if (status < 0) |
| 469 | return status; |
| 470 | |
| 471 | status = req->a_res.status; |
| 472 | if (status == NLM_LCK_GRANTED) { |
| 473 | fl->fl_type = F_UNLCK; |
| 474 | } if (status == NLM_LCK_DENIED) { |
| 475 | /* |
| 476 | * Report the conflicting lock back to the application. |
| 477 | */ |
| 478 | locks_copy_lock(fl, &req->a_res.lock.fl); |
| 479 | fl->fl_pid = 0; |
| 480 | } else { |
| 481 | return nlm_stat_to_errno(req->a_res.status); |
| 482 | } |
| 483 | |
| 484 | return 0; |
| 485 | } |
| 486 | |
| 487 | static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl) |
| 488 | { |
| 489 | memcpy(&new->fl_u.nfs_fl, &fl->fl_u.nfs_fl, sizeof(new->fl_u.nfs_fl)); |
| 490 | nlm_get_lockowner(new->fl_u.nfs_fl.owner); |
| 491 | } |
| 492 | |
| 493 | static void nlmclnt_locks_release_private(struct file_lock *fl) |
| 494 | { |
| 495 | nlm_put_lockowner(fl->fl_u.nfs_fl.owner); |
| 496 | fl->fl_ops = NULL; |
| 497 | } |
| 498 | |
| 499 | static struct file_lock_operations nlmclnt_lock_ops = { |
| 500 | .fl_copy_lock = nlmclnt_locks_copy_lock, |
| 501 | .fl_release_private = nlmclnt_locks_release_private, |
| 502 | }; |
| 503 | |
| 504 | static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host) |
| 505 | { |
| 506 | BUG_ON(fl->fl_ops != NULL); |
| 507 | fl->fl_u.nfs_fl.state = 0; |
| 508 | fl->fl_u.nfs_fl.flags = 0; |
| 509 | fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner); |
| 510 | fl->fl_ops = &nlmclnt_lock_ops; |
| 511 | } |
| 512 | |
| 513 | static void do_vfs_lock(struct file_lock *fl) |
| 514 | { |
| 515 | int res = 0; |
| 516 | switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) { |
| 517 | case FL_POSIX: |
| 518 | res = posix_lock_file_wait(fl->fl_file, fl); |
| 519 | break; |
| 520 | case FL_FLOCK: |
| 521 | res = flock_lock_file_wait(fl->fl_file, fl); |
| 522 | break; |
| 523 | default: |
| 524 | BUG(); |
| 525 | } |
| 526 | if (res < 0) |
| 527 | printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", |
| 528 | __FUNCTION__); |
| 529 | } |
| 530 | |
| 531 | /* |
| 532 | * LOCK: Try to create a lock |
| 533 | * |
| 534 | * Programmer Harassment Alert |
| 535 | * |
| 536 | * When given a blocking lock request in a sync RPC call, the HPUX lockd |
| 537 | * will faithfully return LCK_BLOCKED but never cares to notify us when |
| 538 | * the lock could be granted. This way, our local process could hang |
| 539 | * around forever waiting for the callback. |
| 540 | * |
| 541 | * Solution A: Implement busy-waiting |
| 542 | * Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES}) |
| 543 | * |
| 544 | * For now I am implementing solution A, because I hate the idea of |
| 545 | * re-implementing lockd for a third time in two months. The async |
| 546 | * calls shouldn't be too hard to do, however. |
| 547 | * |
| 548 | * This is one of the lovely things about standards in the NFS area: |
| 549 | * they're so soft and squishy you can't really blame HP for doing this. |
| 550 | */ |
| 551 | static int |
| 552 | nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl) |
| 553 | { |
| 554 | struct nlm_host *host = req->a_host; |
| 555 | struct nlm_res *resp = &req->a_res; |
| 556 | int status; |
| 557 | |
| 558 | if (!host->h_monitored && nsm_monitor(host) < 0) { |
| 559 | printk(KERN_NOTICE "lockd: failed to monitor %s\n", |
| 560 | host->h_name); |
| 561 | status = -ENOLCK; |
| 562 | goto out; |
| 563 | } |
| 564 | |
| 565 | do { |
| 566 | if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0) { |
| 567 | if (resp->status != NLM_LCK_BLOCKED) |
| 568 | break; |
| 569 | status = nlmclnt_block(host, fl, &resp->status); |
| 570 | } |
| 571 | if (status < 0) |
| 572 | goto out; |
| 573 | } while (resp->status == NLM_LCK_BLOCKED && req->a_args.block); |
| 574 | |
| 575 | if (resp->status == NLM_LCK_GRANTED) { |
| 576 | fl->fl_u.nfs_fl.state = host->h_state; |
| 577 | fl->fl_u.nfs_fl.flags |= NFS_LCK_GRANTED; |
| 578 | fl->fl_flags |= FL_SLEEP; |
| 579 | do_vfs_lock(fl); |
| 580 | } |
| 581 | status = nlm_stat_to_errno(resp->status); |
| 582 | out: |
| 583 | nlmclnt_release_lockargs(req); |
| 584 | return status; |
| 585 | } |
| 586 | |
| 587 | /* |
| 588 | * RECLAIM: Try to reclaim a lock |
| 589 | */ |
| 590 | int |
| 591 | nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl) |
| 592 | { |
| 593 | struct nlm_rqst reqst, *req; |
| 594 | int status; |
| 595 | |
| 596 | req = &reqst; |
| 597 | memset(req, 0, sizeof(*req)); |
| 598 | locks_init_lock(&req->a_args.lock.fl); |
| 599 | locks_init_lock(&req->a_res.lock.fl); |
| 600 | req->a_host = host; |
| 601 | req->a_flags = 0; |
| 602 | |
| 603 | /* Set up the argument struct */ |
| 604 | nlmclnt_setlockargs(req, fl); |
| 605 | req->a_args.reclaim = 1; |
| 606 | |
| 607 | if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0 |
| 608 | && req->a_res.status == NLM_LCK_GRANTED) |
| 609 | return 0; |
| 610 | |
| 611 | printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d " |
| 612 | "(errno %d, status %d)\n", fl->fl_pid, |
| 613 | status, req->a_res.status); |
| 614 | |
| 615 | /* |
| 616 | * FIXME: This is a serious failure. We can |
| 617 | * |
| 618 | * a. Ignore the problem |
| 619 | * b. Send the owning process some signal (Linux doesn't have |
| 620 | * SIGLOST, though...) |
| 621 | * c. Retry the operation |
| 622 | * |
| 623 | * Until someone comes up with a simple implementation |
| 624 | * for b or c, I'll choose option a. |
| 625 | */ |
| 626 | |
| 627 | return -ENOLCK; |
| 628 | } |
| 629 | |
| 630 | /* |
| 631 | * UNLOCK: remove an existing lock |
| 632 | */ |
| 633 | static int |
| 634 | nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl) |
| 635 | { |
| 636 | struct nlm_res *resp = &req->a_res; |
| 637 | int status; |
| 638 | |
| 639 | /* Clean the GRANTED flag now so the lock doesn't get |
| 640 | * reclaimed while we're stuck in the unlock call. */ |
| 641 | fl->fl_u.nfs_fl.flags &= ~NFS_LCK_GRANTED; |
| 642 | |
| 643 | if (req->a_flags & RPC_TASK_ASYNC) { |
| 644 | status = nlmclnt_async_call(req, NLMPROC_UNLOCK, |
| 645 | nlmclnt_unlock_callback); |
| 646 | /* Hrmf... Do the unlock early since locks_remove_posix() |
| 647 | * really expects us to free the lock synchronously */ |
| 648 | do_vfs_lock(fl); |
| 649 | if (status < 0) { |
| 650 | nlmclnt_release_lockargs(req); |
| 651 | kfree(req); |
| 652 | } |
| 653 | return status; |
| 654 | } |
| 655 | |
| 656 | status = nlmclnt_call(req, NLMPROC_UNLOCK); |
| 657 | nlmclnt_release_lockargs(req); |
| 658 | if (status < 0) |
| 659 | return status; |
| 660 | |
| 661 | do_vfs_lock(fl); |
| 662 | if (resp->status == NLM_LCK_GRANTED) |
| 663 | return 0; |
| 664 | |
| 665 | if (resp->status != NLM_LCK_DENIED_NOLOCKS) |
| 666 | printk("lockd: unexpected unlock status: %d\n", resp->status); |
| 667 | |
| 668 | /* What to do now? I'm out of my depth... */ |
| 669 | |
| 670 | return -ENOLCK; |
| 671 | } |
| 672 | |
| 673 | static void |
| 674 | nlmclnt_unlock_callback(struct rpc_task *task) |
| 675 | { |
| 676 | struct nlm_rqst *req = (struct nlm_rqst *) task->tk_calldata; |
| 677 | int status = req->a_res.status; |
| 678 | |
| 679 | if (RPC_ASSASSINATED(task)) |
| 680 | goto die; |
| 681 | |
| 682 | if (task->tk_status < 0) { |
| 683 | dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status); |
| 684 | goto retry_rebind; |
| 685 | } |
| 686 | if (status == NLM_LCK_DENIED_GRACE_PERIOD) { |
| 687 | rpc_delay(task, NLMCLNT_GRACE_WAIT); |
| 688 | goto retry_unlock; |
| 689 | } |
| 690 | if (status != NLM_LCK_GRANTED) |
| 691 | printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status); |
| 692 | die: |
| 693 | nlm_release_host(req->a_host); |
| 694 | nlmclnt_release_lockargs(req); |
| 695 | kfree(req); |
| 696 | return; |
| 697 | retry_rebind: |
| 698 | nlm_rebind_host(req->a_host); |
| 699 | retry_unlock: |
| 700 | rpc_restart_call(task); |
| 701 | } |
| 702 | |
| 703 | /* |
| 704 | * Cancel a blocked lock request. |
| 705 | * We always use an async RPC call for this in order not to hang a |
| 706 | * process that has been Ctrl-C'ed. |
| 707 | */ |
| 708 | int |
| 709 | nlmclnt_cancel(struct nlm_host *host, struct file_lock *fl) |
| 710 | { |
| 711 | struct nlm_rqst *req; |
| 712 | unsigned long flags; |
| 713 | sigset_t oldset; |
| 714 | int status; |
| 715 | |
| 716 | /* Block all signals while setting up call */ |
| 717 | spin_lock_irqsave(¤t->sighand->siglock, flags); |
| 718 | oldset = current->blocked; |
| 719 | sigfillset(¤t->blocked); |
| 720 | recalc_sigpending(); |
| 721 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); |
| 722 | |
| 723 | req = nlmclnt_alloc_call(); |
| 724 | if (!req) |
| 725 | return -ENOMEM; |
| 726 | req->a_host = host; |
| 727 | req->a_flags = RPC_TASK_ASYNC; |
| 728 | |
| 729 | nlmclnt_setlockargs(req, fl); |
| 730 | |
| 731 | status = nlmclnt_async_call(req, NLMPROC_CANCEL, |
| 732 | nlmclnt_cancel_callback); |
| 733 | if (status < 0) { |
| 734 | nlmclnt_release_lockargs(req); |
| 735 | kfree(req); |
| 736 | } |
| 737 | |
| 738 | spin_lock_irqsave(¤t->sighand->siglock, flags); |
| 739 | current->blocked = oldset; |
| 740 | recalc_sigpending(); |
| 741 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); |
| 742 | |
| 743 | return status; |
| 744 | } |
| 745 | |
| 746 | static void |
| 747 | nlmclnt_cancel_callback(struct rpc_task *task) |
| 748 | { |
| 749 | struct nlm_rqst *req = (struct nlm_rqst *) task->tk_calldata; |
| 750 | |
| 751 | if (RPC_ASSASSINATED(task)) |
| 752 | goto die; |
| 753 | |
| 754 | if (task->tk_status < 0) { |
| 755 | dprintk("lockd: CANCEL call error %d, retrying.\n", |
| 756 | task->tk_status); |
| 757 | goto retry_cancel; |
| 758 | } |
| 759 | |
| 760 | dprintk("lockd: cancel status %d (task %d)\n", |
| 761 | req->a_res.status, task->tk_pid); |
| 762 | |
| 763 | switch (req->a_res.status) { |
| 764 | case NLM_LCK_GRANTED: |
| 765 | case NLM_LCK_DENIED_GRACE_PERIOD: |
| 766 | /* Everything's good */ |
| 767 | break; |
| 768 | case NLM_LCK_DENIED_NOLOCKS: |
| 769 | dprintk("lockd: CANCEL failed (server has no locks)\n"); |
| 770 | goto retry_cancel; |
| 771 | default: |
| 772 | printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n", |
| 773 | req->a_res.status); |
| 774 | } |
| 775 | |
| 776 | die: |
| 777 | nlm_release_host(req->a_host); |
| 778 | nlmclnt_release_lockargs(req); |
| 779 | kfree(req); |
| 780 | return; |
| 781 | |
| 782 | retry_cancel: |
| 783 | nlm_rebind_host(req->a_host); |
| 784 | rpc_restart_call(task); |
| 785 | rpc_delay(task, 30 * HZ); |
| 786 | } |
| 787 | |
| 788 | /* |
| 789 | * Convert an NLM status code to a generic kernel errno |
| 790 | */ |
| 791 | static int |
| 792 | nlm_stat_to_errno(u32 status) |
| 793 | { |
| 794 | switch(status) { |
| 795 | case NLM_LCK_GRANTED: |
| 796 | return 0; |
| 797 | case NLM_LCK_DENIED: |
| 798 | return -EAGAIN; |
| 799 | case NLM_LCK_DENIED_NOLOCKS: |
| 800 | case NLM_LCK_DENIED_GRACE_PERIOD: |
| 801 | return -ENOLCK; |
| 802 | case NLM_LCK_BLOCKED: |
| 803 | printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n"); |
| 804 | return -ENOLCK; |
| 805 | #ifdef CONFIG_LOCKD_V4 |
| 806 | case NLM_DEADLCK: |
| 807 | return -EDEADLK; |
| 808 | case NLM_ROFS: |
| 809 | return -EROFS; |
| 810 | case NLM_STALE_FH: |
| 811 | return -ESTALE; |
| 812 | case NLM_FBIG: |
| 813 | return -EOVERFLOW; |
| 814 | case NLM_FAILED: |
| 815 | return -ENOLCK; |
| 816 | #endif |
| 817 | } |
| 818 | printk(KERN_NOTICE "lockd: unexpected server status %d\n", status); |
| 819 | return -ENOLCK; |
| 820 | } |