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