| 1 | /* |
| 2 | FUSE: Filesystem in Userspace |
| 3 | Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu> |
| 4 | |
| 5 | This program can be distributed under the terms of the GNU GPL. |
| 6 | See the file COPYING. |
| 7 | */ |
| 8 | |
| 9 | #include "fuse_i.h" |
| 10 | |
| 11 | #include <linux/init.h> |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/poll.h> |
| 14 | #include <linux/uio.h> |
| 15 | #include <linux/miscdevice.h> |
| 16 | #include <linux/pagemap.h> |
| 17 | #include <linux/file.h> |
| 18 | #include <linux/slab.h> |
| 19 | |
| 20 | MODULE_ALIAS_MISCDEV(FUSE_MINOR); |
| 21 | |
| 22 | static struct kmem_cache *fuse_req_cachep; |
| 23 | |
| 24 | static struct fuse_conn *fuse_get_conn(struct file *file) |
| 25 | { |
| 26 | /* |
| 27 | * Lockless access is OK, because file->private data is set |
| 28 | * once during mount and is valid until the file is released. |
| 29 | */ |
| 30 | return file->private_data; |
| 31 | } |
| 32 | |
| 33 | static void fuse_request_init(struct fuse_req *req) |
| 34 | { |
| 35 | memset(req, 0, sizeof(*req)); |
| 36 | INIT_LIST_HEAD(&req->list); |
| 37 | INIT_LIST_HEAD(&req->intr_entry); |
| 38 | init_waitqueue_head(&req->waitq); |
| 39 | atomic_set(&req->count, 1); |
| 40 | } |
| 41 | |
| 42 | struct fuse_req *fuse_request_alloc(void) |
| 43 | { |
| 44 | struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_KERNEL); |
| 45 | if (req) |
| 46 | fuse_request_init(req); |
| 47 | return req; |
| 48 | } |
| 49 | EXPORT_SYMBOL_GPL(fuse_request_alloc); |
| 50 | |
| 51 | struct fuse_req *fuse_request_alloc_nofs(void) |
| 52 | { |
| 53 | struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_NOFS); |
| 54 | if (req) |
| 55 | fuse_request_init(req); |
| 56 | return req; |
| 57 | } |
| 58 | |
| 59 | void fuse_request_free(struct fuse_req *req) |
| 60 | { |
| 61 | kmem_cache_free(fuse_req_cachep, req); |
| 62 | } |
| 63 | |
| 64 | static void block_sigs(sigset_t *oldset) |
| 65 | { |
| 66 | sigset_t mask; |
| 67 | |
| 68 | siginitsetinv(&mask, sigmask(SIGKILL)); |
| 69 | sigprocmask(SIG_BLOCK, &mask, oldset); |
| 70 | } |
| 71 | |
| 72 | static void restore_sigs(sigset_t *oldset) |
| 73 | { |
| 74 | sigprocmask(SIG_SETMASK, oldset, NULL); |
| 75 | } |
| 76 | |
| 77 | static void __fuse_get_request(struct fuse_req *req) |
| 78 | { |
| 79 | atomic_inc(&req->count); |
| 80 | } |
| 81 | |
| 82 | /* Must be called with > 1 refcount */ |
| 83 | static void __fuse_put_request(struct fuse_req *req) |
| 84 | { |
| 85 | BUG_ON(atomic_read(&req->count) < 2); |
| 86 | atomic_dec(&req->count); |
| 87 | } |
| 88 | |
| 89 | static void fuse_req_init_context(struct fuse_req *req) |
| 90 | { |
| 91 | req->in.h.uid = current_fsuid(); |
| 92 | req->in.h.gid = current_fsgid(); |
| 93 | req->in.h.pid = current->pid; |
| 94 | } |
| 95 | |
| 96 | struct fuse_req *fuse_get_req(struct fuse_conn *fc) |
| 97 | { |
| 98 | struct fuse_req *req; |
| 99 | sigset_t oldset; |
| 100 | int intr; |
| 101 | int err; |
| 102 | |
| 103 | atomic_inc(&fc->num_waiting); |
| 104 | block_sigs(&oldset); |
| 105 | intr = wait_event_interruptible(fc->blocked_waitq, !fc->blocked); |
| 106 | restore_sigs(&oldset); |
| 107 | err = -EINTR; |
| 108 | if (intr) |
| 109 | goto out; |
| 110 | |
| 111 | err = -ENOTCONN; |
| 112 | if (!fc->connected) |
| 113 | goto out; |
| 114 | |
| 115 | req = fuse_request_alloc(); |
| 116 | err = -ENOMEM; |
| 117 | if (!req) |
| 118 | goto out; |
| 119 | |
| 120 | fuse_req_init_context(req); |
| 121 | req->waiting = 1; |
| 122 | return req; |
| 123 | |
| 124 | out: |
| 125 | atomic_dec(&fc->num_waiting); |
| 126 | return ERR_PTR(err); |
| 127 | } |
| 128 | EXPORT_SYMBOL_GPL(fuse_get_req); |
| 129 | |
| 130 | /* |
| 131 | * Return request in fuse_file->reserved_req. However that may |
| 132 | * currently be in use. If that is the case, wait for it to become |
| 133 | * available. |
| 134 | */ |
| 135 | static struct fuse_req *get_reserved_req(struct fuse_conn *fc, |
| 136 | struct file *file) |
| 137 | { |
| 138 | struct fuse_req *req = NULL; |
| 139 | struct fuse_file *ff = file->private_data; |
| 140 | |
| 141 | do { |
| 142 | wait_event(fc->reserved_req_waitq, ff->reserved_req); |
| 143 | spin_lock(&fc->lock); |
| 144 | if (ff->reserved_req) { |
| 145 | req = ff->reserved_req; |
| 146 | ff->reserved_req = NULL; |
| 147 | get_file(file); |
| 148 | req->stolen_file = file; |
| 149 | } |
| 150 | spin_unlock(&fc->lock); |
| 151 | } while (!req); |
| 152 | |
| 153 | return req; |
| 154 | } |
| 155 | |
| 156 | /* |
| 157 | * Put stolen request back into fuse_file->reserved_req |
| 158 | */ |
| 159 | static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req) |
| 160 | { |
| 161 | struct file *file = req->stolen_file; |
| 162 | struct fuse_file *ff = file->private_data; |
| 163 | |
| 164 | spin_lock(&fc->lock); |
| 165 | fuse_request_init(req); |
| 166 | BUG_ON(ff->reserved_req); |
| 167 | ff->reserved_req = req; |
| 168 | wake_up_all(&fc->reserved_req_waitq); |
| 169 | spin_unlock(&fc->lock); |
| 170 | fput(file); |
| 171 | } |
| 172 | |
| 173 | /* |
| 174 | * Gets a requests for a file operation, always succeeds |
| 175 | * |
| 176 | * This is used for sending the FLUSH request, which must get to |
| 177 | * userspace, due to POSIX locks which may need to be unlocked. |
| 178 | * |
| 179 | * If allocation fails due to OOM, use the reserved request in |
| 180 | * fuse_file. |
| 181 | * |
| 182 | * This is very unlikely to deadlock accidentally, since the |
| 183 | * filesystem should not have it's own file open. If deadlock is |
| 184 | * intentional, it can still be broken by "aborting" the filesystem. |
| 185 | */ |
| 186 | struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file) |
| 187 | { |
| 188 | struct fuse_req *req; |
| 189 | |
| 190 | atomic_inc(&fc->num_waiting); |
| 191 | wait_event(fc->blocked_waitq, !fc->blocked); |
| 192 | req = fuse_request_alloc(); |
| 193 | if (!req) |
| 194 | req = get_reserved_req(fc, file); |
| 195 | |
| 196 | fuse_req_init_context(req); |
| 197 | req->waiting = 1; |
| 198 | return req; |
| 199 | } |
| 200 | |
| 201 | void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req) |
| 202 | { |
| 203 | if (atomic_dec_and_test(&req->count)) { |
| 204 | if (req->waiting) |
| 205 | atomic_dec(&fc->num_waiting); |
| 206 | |
| 207 | if (req->stolen_file) |
| 208 | put_reserved_req(fc, req); |
| 209 | else |
| 210 | fuse_request_free(req); |
| 211 | } |
| 212 | } |
| 213 | EXPORT_SYMBOL_GPL(fuse_put_request); |
| 214 | |
| 215 | static unsigned len_args(unsigned numargs, struct fuse_arg *args) |
| 216 | { |
| 217 | unsigned nbytes = 0; |
| 218 | unsigned i; |
| 219 | |
| 220 | for (i = 0; i < numargs; i++) |
| 221 | nbytes += args[i].size; |
| 222 | |
| 223 | return nbytes; |
| 224 | } |
| 225 | |
| 226 | static u64 fuse_get_unique(struct fuse_conn *fc) |
| 227 | { |
| 228 | fc->reqctr++; |
| 229 | /* zero is special */ |
| 230 | if (fc->reqctr == 0) |
| 231 | fc->reqctr = 1; |
| 232 | |
| 233 | return fc->reqctr; |
| 234 | } |
| 235 | |
| 236 | static void queue_request(struct fuse_conn *fc, struct fuse_req *req) |
| 237 | { |
| 238 | req->in.h.unique = fuse_get_unique(fc); |
| 239 | req->in.h.len = sizeof(struct fuse_in_header) + |
| 240 | len_args(req->in.numargs, (struct fuse_arg *) req->in.args); |
| 241 | list_add_tail(&req->list, &fc->pending); |
| 242 | req->state = FUSE_REQ_PENDING; |
| 243 | if (!req->waiting) { |
| 244 | req->waiting = 1; |
| 245 | atomic_inc(&fc->num_waiting); |
| 246 | } |
| 247 | wake_up(&fc->waitq); |
| 248 | kill_fasync(&fc->fasync, SIGIO, POLL_IN); |
| 249 | } |
| 250 | |
| 251 | static void flush_bg_queue(struct fuse_conn *fc) |
| 252 | { |
| 253 | while (fc->active_background < fc->max_background && |
| 254 | !list_empty(&fc->bg_queue)) { |
| 255 | struct fuse_req *req; |
| 256 | |
| 257 | req = list_entry(fc->bg_queue.next, struct fuse_req, list); |
| 258 | list_del(&req->list); |
| 259 | fc->active_background++; |
| 260 | queue_request(fc, req); |
| 261 | } |
| 262 | } |
| 263 | |
| 264 | /* |
| 265 | * This function is called when a request is finished. Either a reply |
| 266 | * has arrived or it was aborted (and not yet sent) or some error |
| 267 | * occurred during communication with userspace, or the device file |
| 268 | * was closed. The requester thread is woken up (if still waiting), |
| 269 | * the 'end' callback is called if given, else the reference to the |
| 270 | * request is released |
| 271 | * |
| 272 | * Called with fc->lock, unlocks it |
| 273 | */ |
| 274 | static void request_end(struct fuse_conn *fc, struct fuse_req *req) |
| 275 | __releases(&fc->lock) |
| 276 | { |
| 277 | void (*end) (struct fuse_conn *, struct fuse_req *) = req->end; |
| 278 | req->end = NULL; |
| 279 | list_del(&req->list); |
| 280 | list_del(&req->intr_entry); |
| 281 | req->state = FUSE_REQ_FINISHED; |
| 282 | if (req->background) { |
| 283 | if (fc->num_background == fc->max_background) { |
| 284 | fc->blocked = 0; |
| 285 | wake_up_all(&fc->blocked_waitq); |
| 286 | } |
| 287 | if (fc->num_background == fc->congestion_threshold && |
| 288 | fc->connected && fc->bdi_initialized) { |
| 289 | clear_bdi_congested(&fc->bdi, BLK_RW_SYNC); |
| 290 | clear_bdi_congested(&fc->bdi, BLK_RW_ASYNC); |
| 291 | } |
| 292 | fc->num_background--; |
| 293 | fc->active_background--; |
| 294 | flush_bg_queue(fc); |
| 295 | } |
| 296 | spin_unlock(&fc->lock); |
| 297 | wake_up(&req->waitq); |
| 298 | if (end) |
| 299 | end(fc, req); |
| 300 | fuse_put_request(fc, req); |
| 301 | } |
| 302 | |
| 303 | static void wait_answer_interruptible(struct fuse_conn *fc, |
| 304 | struct fuse_req *req) |
| 305 | __releases(&fc->lock) |
| 306 | __acquires(&fc->lock) |
| 307 | { |
| 308 | if (signal_pending(current)) |
| 309 | return; |
| 310 | |
| 311 | spin_unlock(&fc->lock); |
| 312 | wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED); |
| 313 | spin_lock(&fc->lock); |
| 314 | } |
| 315 | |
| 316 | static void queue_interrupt(struct fuse_conn *fc, struct fuse_req *req) |
| 317 | { |
| 318 | list_add_tail(&req->intr_entry, &fc->interrupts); |
| 319 | wake_up(&fc->waitq); |
| 320 | kill_fasync(&fc->fasync, SIGIO, POLL_IN); |
| 321 | } |
| 322 | |
| 323 | static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req) |
| 324 | __releases(&fc->lock) |
| 325 | __acquires(&fc->lock) |
| 326 | { |
| 327 | if (!fc->no_interrupt) { |
| 328 | /* Any signal may interrupt this */ |
| 329 | wait_answer_interruptible(fc, req); |
| 330 | |
| 331 | if (req->aborted) |
| 332 | goto aborted; |
| 333 | if (req->state == FUSE_REQ_FINISHED) |
| 334 | return; |
| 335 | |
| 336 | req->interrupted = 1; |
| 337 | if (req->state == FUSE_REQ_SENT) |
| 338 | queue_interrupt(fc, req); |
| 339 | } |
| 340 | |
| 341 | if (!req->force) { |
| 342 | sigset_t oldset; |
| 343 | |
| 344 | /* Only fatal signals may interrupt this */ |
| 345 | block_sigs(&oldset); |
| 346 | wait_answer_interruptible(fc, req); |
| 347 | restore_sigs(&oldset); |
| 348 | |
| 349 | if (req->aborted) |
| 350 | goto aborted; |
| 351 | if (req->state == FUSE_REQ_FINISHED) |
| 352 | return; |
| 353 | |
| 354 | /* Request is not yet in userspace, bail out */ |
| 355 | if (req->state == FUSE_REQ_PENDING) { |
| 356 | list_del(&req->list); |
| 357 | __fuse_put_request(req); |
| 358 | req->out.h.error = -EINTR; |
| 359 | return; |
| 360 | } |
| 361 | } |
| 362 | |
| 363 | /* |
| 364 | * Either request is already in userspace, or it was forced. |
| 365 | * Wait it out. |
| 366 | */ |
| 367 | spin_unlock(&fc->lock); |
| 368 | wait_event(req->waitq, req->state == FUSE_REQ_FINISHED); |
| 369 | spin_lock(&fc->lock); |
| 370 | |
| 371 | if (!req->aborted) |
| 372 | return; |
| 373 | |
| 374 | aborted: |
| 375 | BUG_ON(req->state != FUSE_REQ_FINISHED); |
| 376 | if (req->locked) { |
| 377 | /* This is uninterruptible sleep, because data is |
| 378 | being copied to/from the buffers of req. During |
| 379 | locked state, there mustn't be any filesystem |
| 380 | operation (e.g. page fault), since that could lead |
| 381 | to deadlock */ |
| 382 | spin_unlock(&fc->lock); |
| 383 | wait_event(req->waitq, !req->locked); |
| 384 | spin_lock(&fc->lock); |
| 385 | } |
| 386 | } |
| 387 | |
| 388 | void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req) |
| 389 | { |
| 390 | req->isreply = 1; |
| 391 | spin_lock(&fc->lock); |
| 392 | if (!fc->connected) |
| 393 | req->out.h.error = -ENOTCONN; |
| 394 | else if (fc->conn_error) |
| 395 | req->out.h.error = -ECONNREFUSED; |
| 396 | else { |
| 397 | queue_request(fc, req); |
| 398 | /* acquire extra reference, since request is still needed |
| 399 | after request_end() */ |
| 400 | __fuse_get_request(req); |
| 401 | |
| 402 | request_wait_answer(fc, req); |
| 403 | } |
| 404 | spin_unlock(&fc->lock); |
| 405 | } |
| 406 | EXPORT_SYMBOL_GPL(fuse_request_send); |
| 407 | |
| 408 | static void fuse_request_send_nowait_locked(struct fuse_conn *fc, |
| 409 | struct fuse_req *req) |
| 410 | { |
| 411 | req->background = 1; |
| 412 | fc->num_background++; |
| 413 | if (fc->num_background == fc->max_background) |
| 414 | fc->blocked = 1; |
| 415 | if (fc->num_background == fc->congestion_threshold && |
| 416 | fc->bdi_initialized) { |
| 417 | set_bdi_congested(&fc->bdi, BLK_RW_SYNC); |
| 418 | set_bdi_congested(&fc->bdi, BLK_RW_ASYNC); |
| 419 | } |
| 420 | list_add_tail(&req->list, &fc->bg_queue); |
| 421 | flush_bg_queue(fc); |
| 422 | } |
| 423 | |
| 424 | static void fuse_request_send_nowait(struct fuse_conn *fc, struct fuse_req *req) |
| 425 | { |
| 426 | spin_lock(&fc->lock); |
| 427 | if (fc->connected) { |
| 428 | fuse_request_send_nowait_locked(fc, req); |
| 429 | spin_unlock(&fc->lock); |
| 430 | } else { |
| 431 | req->out.h.error = -ENOTCONN; |
| 432 | request_end(fc, req); |
| 433 | } |
| 434 | } |
| 435 | |
| 436 | void fuse_request_send_noreply(struct fuse_conn *fc, struct fuse_req *req) |
| 437 | { |
| 438 | req->isreply = 0; |
| 439 | fuse_request_send_nowait(fc, req); |
| 440 | } |
| 441 | |
| 442 | void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req) |
| 443 | { |
| 444 | req->isreply = 1; |
| 445 | fuse_request_send_nowait(fc, req); |
| 446 | } |
| 447 | EXPORT_SYMBOL_GPL(fuse_request_send_background); |
| 448 | |
| 449 | /* |
| 450 | * Called under fc->lock |
| 451 | * |
| 452 | * fc->connected must have been checked previously |
| 453 | */ |
| 454 | void fuse_request_send_background_locked(struct fuse_conn *fc, |
| 455 | struct fuse_req *req) |
| 456 | { |
| 457 | req->isreply = 1; |
| 458 | fuse_request_send_nowait_locked(fc, req); |
| 459 | } |
| 460 | |
| 461 | /* |
| 462 | * Lock the request. Up to the next unlock_request() there mustn't be |
| 463 | * anything that could cause a page-fault. If the request was already |
| 464 | * aborted bail out. |
| 465 | */ |
| 466 | static int lock_request(struct fuse_conn *fc, struct fuse_req *req) |
| 467 | { |
| 468 | int err = 0; |
| 469 | if (req) { |
| 470 | spin_lock(&fc->lock); |
| 471 | if (req->aborted) |
| 472 | err = -ENOENT; |
| 473 | else |
| 474 | req->locked = 1; |
| 475 | spin_unlock(&fc->lock); |
| 476 | } |
| 477 | return err; |
| 478 | } |
| 479 | |
| 480 | /* |
| 481 | * Unlock request. If it was aborted during being locked, the |
| 482 | * requester thread is currently waiting for it to be unlocked, so |
| 483 | * wake it up. |
| 484 | */ |
| 485 | static void unlock_request(struct fuse_conn *fc, struct fuse_req *req) |
| 486 | { |
| 487 | if (req) { |
| 488 | spin_lock(&fc->lock); |
| 489 | req->locked = 0; |
| 490 | if (req->aborted) |
| 491 | wake_up(&req->waitq); |
| 492 | spin_unlock(&fc->lock); |
| 493 | } |
| 494 | } |
| 495 | |
| 496 | struct fuse_copy_state { |
| 497 | struct fuse_conn *fc; |
| 498 | int write; |
| 499 | struct fuse_req *req; |
| 500 | const struct iovec *iov; |
| 501 | unsigned long nr_segs; |
| 502 | unsigned long seglen; |
| 503 | unsigned long addr; |
| 504 | struct page *pg; |
| 505 | void *mapaddr; |
| 506 | void *buf; |
| 507 | unsigned len; |
| 508 | }; |
| 509 | |
| 510 | static void fuse_copy_init(struct fuse_copy_state *cs, struct fuse_conn *fc, |
| 511 | int write, struct fuse_req *req, |
| 512 | const struct iovec *iov, unsigned long nr_segs) |
| 513 | { |
| 514 | memset(cs, 0, sizeof(*cs)); |
| 515 | cs->fc = fc; |
| 516 | cs->write = write; |
| 517 | cs->req = req; |
| 518 | cs->iov = iov; |
| 519 | cs->nr_segs = nr_segs; |
| 520 | } |
| 521 | |
| 522 | /* Unmap and put previous page of userspace buffer */ |
| 523 | static void fuse_copy_finish(struct fuse_copy_state *cs) |
| 524 | { |
| 525 | if (cs->mapaddr) { |
| 526 | kunmap_atomic(cs->mapaddr, KM_USER0); |
| 527 | if (cs->write) { |
| 528 | flush_dcache_page(cs->pg); |
| 529 | set_page_dirty_lock(cs->pg); |
| 530 | } |
| 531 | put_page(cs->pg); |
| 532 | cs->mapaddr = NULL; |
| 533 | } |
| 534 | } |
| 535 | |
| 536 | /* |
| 537 | * Get another pagefull of userspace buffer, and map it to kernel |
| 538 | * address space, and lock request |
| 539 | */ |
| 540 | static int fuse_copy_fill(struct fuse_copy_state *cs) |
| 541 | { |
| 542 | unsigned long offset; |
| 543 | int err; |
| 544 | |
| 545 | unlock_request(cs->fc, cs->req); |
| 546 | fuse_copy_finish(cs); |
| 547 | if (!cs->seglen) { |
| 548 | BUG_ON(!cs->nr_segs); |
| 549 | cs->seglen = cs->iov[0].iov_len; |
| 550 | cs->addr = (unsigned long) cs->iov[0].iov_base; |
| 551 | cs->iov++; |
| 552 | cs->nr_segs--; |
| 553 | } |
| 554 | down_read(¤t->mm->mmap_sem); |
| 555 | err = get_user_pages(current, current->mm, cs->addr, 1, cs->write, 0, |
| 556 | &cs->pg, NULL); |
| 557 | up_read(¤t->mm->mmap_sem); |
| 558 | if (err < 0) |
| 559 | return err; |
| 560 | BUG_ON(err != 1); |
| 561 | offset = cs->addr % PAGE_SIZE; |
| 562 | cs->mapaddr = kmap_atomic(cs->pg, KM_USER0); |
| 563 | cs->buf = cs->mapaddr + offset; |
| 564 | cs->len = min(PAGE_SIZE - offset, cs->seglen); |
| 565 | cs->seglen -= cs->len; |
| 566 | cs->addr += cs->len; |
| 567 | |
| 568 | return lock_request(cs->fc, cs->req); |
| 569 | } |
| 570 | |
| 571 | /* Do as much copy to/from userspace buffer as we can */ |
| 572 | static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size) |
| 573 | { |
| 574 | unsigned ncpy = min(*size, cs->len); |
| 575 | if (val) { |
| 576 | if (cs->write) |
| 577 | memcpy(cs->buf, *val, ncpy); |
| 578 | else |
| 579 | memcpy(*val, cs->buf, ncpy); |
| 580 | *val += ncpy; |
| 581 | } |
| 582 | *size -= ncpy; |
| 583 | cs->len -= ncpy; |
| 584 | cs->buf += ncpy; |
| 585 | return ncpy; |
| 586 | } |
| 587 | |
| 588 | /* |
| 589 | * Copy a page in the request to/from the userspace buffer. Must be |
| 590 | * done atomically |
| 591 | */ |
| 592 | static int fuse_copy_page(struct fuse_copy_state *cs, struct page *page, |
| 593 | unsigned offset, unsigned count, int zeroing) |
| 594 | { |
| 595 | if (page && zeroing && count < PAGE_SIZE) { |
| 596 | void *mapaddr = kmap_atomic(page, KM_USER1); |
| 597 | memset(mapaddr, 0, PAGE_SIZE); |
| 598 | kunmap_atomic(mapaddr, KM_USER1); |
| 599 | } |
| 600 | while (count) { |
| 601 | if (!cs->len) { |
| 602 | int err = fuse_copy_fill(cs); |
| 603 | if (err) |
| 604 | return err; |
| 605 | } |
| 606 | if (page) { |
| 607 | void *mapaddr = kmap_atomic(page, KM_USER1); |
| 608 | void *buf = mapaddr + offset; |
| 609 | offset += fuse_copy_do(cs, &buf, &count); |
| 610 | kunmap_atomic(mapaddr, KM_USER1); |
| 611 | } else |
| 612 | offset += fuse_copy_do(cs, NULL, &count); |
| 613 | } |
| 614 | if (page && !cs->write) |
| 615 | flush_dcache_page(page); |
| 616 | return 0; |
| 617 | } |
| 618 | |
| 619 | /* Copy pages in the request to/from userspace buffer */ |
| 620 | static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes, |
| 621 | int zeroing) |
| 622 | { |
| 623 | unsigned i; |
| 624 | struct fuse_req *req = cs->req; |
| 625 | unsigned offset = req->page_offset; |
| 626 | unsigned count = min(nbytes, (unsigned) PAGE_SIZE - offset); |
| 627 | |
| 628 | for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) { |
| 629 | struct page *page = req->pages[i]; |
| 630 | int err = fuse_copy_page(cs, page, offset, count, zeroing); |
| 631 | if (err) |
| 632 | return err; |
| 633 | |
| 634 | nbytes -= count; |
| 635 | count = min(nbytes, (unsigned) PAGE_SIZE); |
| 636 | offset = 0; |
| 637 | } |
| 638 | return 0; |
| 639 | } |
| 640 | |
| 641 | /* Copy a single argument in the request to/from userspace buffer */ |
| 642 | static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size) |
| 643 | { |
| 644 | while (size) { |
| 645 | if (!cs->len) { |
| 646 | int err = fuse_copy_fill(cs); |
| 647 | if (err) |
| 648 | return err; |
| 649 | } |
| 650 | fuse_copy_do(cs, &val, &size); |
| 651 | } |
| 652 | return 0; |
| 653 | } |
| 654 | |
| 655 | /* Copy request arguments to/from userspace buffer */ |
| 656 | static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs, |
| 657 | unsigned argpages, struct fuse_arg *args, |
| 658 | int zeroing) |
| 659 | { |
| 660 | int err = 0; |
| 661 | unsigned i; |
| 662 | |
| 663 | for (i = 0; !err && i < numargs; i++) { |
| 664 | struct fuse_arg *arg = &args[i]; |
| 665 | if (i == numargs - 1 && argpages) |
| 666 | err = fuse_copy_pages(cs, arg->size, zeroing); |
| 667 | else |
| 668 | err = fuse_copy_one(cs, arg->value, arg->size); |
| 669 | } |
| 670 | return err; |
| 671 | } |
| 672 | |
| 673 | static int request_pending(struct fuse_conn *fc) |
| 674 | { |
| 675 | return !list_empty(&fc->pending) || !list_empty(&fc->interrupts); |
| 676 | } |
| 677 | |
| 678 | /* Wait until a request is available on the pending list */ |
| 679 | static void request_wait(struct fuse_conn *fc) |
| 680 | __releases(&fc->lock) |
| 681 | __acquires(&fc->lock) |
| 682 | { |
| 683 | DECLARE_WAITQUEUE(wait, current); |
| 684 | |
| 685 | add_wait_queue_exclusive(&fc->waitq, &wait); |
| 686 | while (fc->connected && !request_pending(fc)) { |
| 687 | set_current_state(TASK_INTERRUPTIBLE); |
| 688 | if (signal_pending(current)) |
| 689 | break; |
| 690 | |
| 691 | spin_unlock(&fc->lock); |
| 692 | schedule(); |
| 693 | spin_lock(&fc->lock); |
| 694 | } |
| 695 | set_current_state(TASK_RUNNING); |
| 696 | remove_wait_queue(&fc->waitq, &wait); |
| 697 | } |
| 698 | |
| 699 | /* |
| 700 | * Transfer an interrupt request to userspace |
| 701 | * |
| 702 | * Unlike other requests this is assembled on demand, without a need |
| 703 | * to allocate a separate fuse_req structure. |
| 704 | * |
| 705 | * Called with fc->lock held, releases it |
| 706 | */ |
| 707 | static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_req *req, |
| 708 | const struct iovec *iov, unsigned long nr_segs) |
| 709 | __releases(&fc->lock) |
| 710 | { |
| 711 | struct fuse_copy_state cs; |
| 712 | struct fuse_in_header ih; |
| 713 | struct fuse_interrupt_in arg; |
| 714 | unsigned reqsize = sizeof(ih) + sizeof(arg); |
| 715 | int err; |
| 716 | |
| 717 | list_del_init(&req->intr_entry); |
| 718 | req->intr_unique = fuse_get_unique(fc); |
| 719 | memset(&ih, 0, sizeof(ih)); |
| 720 | memset(&arg, 0, sizeof(arg)); |
| 721 | ih.len = reqsize; |
| 722 | ih.opcode = FUSE_INTERRUPT; |
| 723 | ih.unique = req->intr_unique; |
| 724 | arg.unique = req->in.h.unique; |
| 725 | |
| 726 | spin_unlock(&fc->lock); |
| 727 | if (iov_length(iov, nr_segs) < reqsize) |
| 728 | return -EINVAL; |
| 729 | |
| 730 | fuse_copy_init(&cs, fc, 1, NULL, iov, nr_segs); |
| 731 | err = fuse_copy_one(&cs, &ih, sizeof(ih)); |
| 732 | if (!err) |
| 733 | err = fuse_copy_one(&cs, &arg, sizeof(arg)); |
| 734 | fuse_copy_finish(&cs); |
| 735 | |
| 736 | return err ? err : reqsize; |
| 737 | } |
| 738 | |
| 739 | /* |
| 740 | * Read a single request into the userspace filesystem's buffer. This |
| 741 | * function waits until a request is available, then removes it from |
| 742 | * the pending list and copies request data to userspace buffer. If |
| 743 | * no reply is needed (FORGET) or request has been aborted or there |
| 744 | * was an error during the copying then it's finished by calling |
| 745 | * request_end(). Otherwise add it to the processing list, and set |
| 746 | * the 'sent' flag. |
| 747 | */ |
| 748 | static ssize_t fuse_dev_read(struct kiocb *iocb, const struct iovec *iov, |
| 749 | unsigned long nr_segs, loff_t pos) |
| 750 | { |
| 751 | int err; |
| 752 | struct fuse_req *req; |
| 753 | struct fuse_in *in; |
| 754 | struct fuse_copy_state cs; |
| 755 | unsigned reqsize; |
| 756 | struct file *file = iocb->ki_filp; |
| 757 | struct fuse_conn *fc = fuse_get_conn(file); |
| 758 | if (!fc) |
| 759 | return -EPERM; |
| 760 | |
| 761 | restart: |
| 762 | spin_lock(&fc->lock); |
| 763 | err = -EAGAIN; |
| 764 | if ((file->f_flags & O_NONBLOCK) && fc->connected && |
| 765 | !request_pending(fc)) |
| 766 | goto err_unlock; |
| 767 | |
| 768 | request_wait(fc); |
| 769 | err = -ENODEV; |
| 770 | if (!fc->connected) |
| 771 | goto err_unlock; |
| 772 | err = -ERESTARTSYS; |
| 773 | if (!request_pending(fc)) |
| 774 | goto err_unlock; |
| 775 | |
| 776 | if (!list_empty(&fc->interrupts)) { |
| 777 | req = list_entry(fc->interrupts.next, struct fuse_req, |
| 778 | intr_entry); |
| 779 | return fuse_read_interrupt(fc, req, iov, nr_segs); |
| 780 | } |
| 781 | |
| 782 | req = list_entry(fc->pending.next, struct fuse_req, list); |
| 783 | req->state = FUSE_REQ_READING; |
| 784 | list_move(&req->list, &fc->io); |
| 785 | |
| 786 | in = &req->in; |
| 787 | reqsize = in->h.len; |
| 788 | /* If request is too large, reply with an error and restart the read */ |
| 789 | if (iov_length(iov, nr_segs) < reqsize) { |
| 790 | req->out.h.error = -EIO; |
| 791 | /* SETXATTR is special, since it may contain too large data */ |
| 792 | if (in->h.opcode == FUSE_SETXATTR) |
| 793 | req->out.h.error = -E2BIG; |
| 794 | request_end(fc, req); |
| 795 | goto restart; |
| 796 | } |
| 797 | spin_unlock(&fc->lock); |
| 798 | fuse_copy_init(&cs, fc, 1, req, iov, nr_segs); |
| 799 | err = fuse_copy_one(&cs, &in->h, sizeof(in->h)); |
| 800 | if (!err) |
| 801 | err = fuse_copy_args(&cs, in->numargs, in->argpages, |
| 802 | (struct fuse_arg *) in->args, 0); |
| 803 | fuse_copy_finish(&cs); |
| 804 | spin_lock(&fc->lock); |
| 805 | req->locked = 0; |
| 806 | if (req->aborted) { |
| 807 | request_end(fc, req); |
| 808 | return -ENODEV; |
| 809 | } |
| 810 | if (err) { |
| 811 | req->out.h.error = -EIO; |
| 812 | request_end(fc, req); |
| 813 | return err; |
| 814 | } |
| 815 | if (!req->isreply) |
| 816 | request_end(fc, req); |
| 817 | else { |
| 818 | req->state = FUSE_REQ_SENT; |
| 819 | list_move_tail(&req->list, &fc->processing); |
| 820 | if (req->interrupted) |
| 821 | queue_interrupt(fc, req); |
| 822 | spin_unlock(&fc->lock); |
| 823 | } |
| 824 | return reqsize; |
| 825 | |
| 826 | err_unlock: |
| 827 | spin_unlock(&fc->lock); |
| 828 | return err; |
| 829 | } |
| 830 | |
| 831 | static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size, |
| 832 | struct fuse_copy_state *cs) |
| 833 | { |
| 834 | struct fuse_notify_poll_wakeup_out outarg; |
| 835 | int err = -EINVAL; |
| 836 | |
| 837 | if (size != sizeof(outarg)) |
| 838 | goto err; |
| 839 | |
| 840 | err = fuse_copy_one(cs, &outarg, sizeof(outarg)); |
| 841 | if (err) |
| 842 | goto err; |
| 843 | |
| 844 | fuse_copy_finish(cs); |
| 845 | return fuse_notify_poll_wakeup(fc, &outarg); |
| 846 | |
| 847 | err: |
| 848 | fuse_copy_finish(cs); |
| 849 | return err; |
| 850 | } |
| 851 | |
| 852 | static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size, |
| 853 | struct fuse_copy_state *cs) |
| 854 | { |
| 855 | struct fuse_notify_inval_inode_out outarg; |
| 856 | int err = -EINVAL; |
| 857 | |
| 858 | if (size != sizeof(outarg)) |
| 859 | goto err; |
| 860 | |
| 861 | err = fuse_copy_one(cs, &outarg, sizeof(outarg)); |
| 862 | if (err) |
| 863 | goto err; |
| 864 | fuse_copy_finish(cs); |
| 865 | |
| 866 | down_read(&fc->killsb); |
| 867 | err = -ENOENT; |
| 868 | if (!fc->sb) |
| 869 | goto err_unlock; |
| 870 | |
| 871 | err = fuse_reverse_inval_inode(fc->sb, outarg.ino, |
| 872 | outarg.off, outarg.len); |
| 873 | |
| 874 | err_unlock: |
| 875 | up_read(&fc->killsb); |
| 876 | return err; |
| 877 | |
| 878 | err: |
| 879 | fuse_copy_finish(cs); |
| 880 | return err; |
| 881 | } |
| 882 | |
| 883 | static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size, |
| 884 | struct fuse_copy_state *cs) |
| 885 | { |
| 886 | struct fuse_notify_inval_entry_out outarg; |
| 887 | int err = -EINVAL; |
| 888 | char buf[FUSE_NAME_MAX+1]; |
| 889 | struct qstr name; |
| 890 | |
| 891 | if (size < sizeof(outarg)) |
| 892 | goto err; |
| 893 | |
| 894 | err = fuse_copy_one(cs, &outarg, sizeof(outarg)); |
| 895 | if (err) |
| 896 | goto err; |
| 897 | |
| 898 | err = -ENAMETOOLONG; |
| 899 | if (outarg.namelen > FUSE_NAME_MAX) |
| 900 | goto err; |
| 901 | |
| 902 | name.name = buf; |
| 903 | name.len = outarg.namelen; |
| 904 | err = fuse_copy_one(cs, buf, outarg.namelen + 1); |
| 905 | if (err) |
| 906 | goto err; |
| 907 | fuse_copy_finish(cs); |
| 908 | buf[outarg.namelen] = 0; |
| 909 | name.hash = full_name_hash(name.name, name.len); |
| 910 | |
| 911 | down_read(&fc->killsb); |
| 912 | err = -ENOENT; |
| 913 | if (!fc->sb) |
| 914 | goto err_unlock; |
| 915 | |
| 916 | err = fuse_reverse_inval_entry(fc->sb, outarg.parent, &name); |
| 917 | |
| 918 | err_unlock: |
| 919 | up_read(&fc->killsb); |
| 920 | return err; |
| 921 | |
| 922 | err: |
| 923 | fuse_copy_finish(cs); |
| 924 | return err; |
| 925 | } |
| 926 | |
| 927 | static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code, |
| 928 | unsigned int size, struct fuse_copy_state *cs) |
| 929 | { |
| 930 | switch (code) { |
| 931 | case FUSE_NOTIFY_POLL: |
| 932 | return fuse_notify_poll(fc, size, cs); |
| 933 | |
| 934 | case FUSE_NOTIFY_INVAL_INODE: |
| 935 | return fuse_notify_inval_inode(fc, size, cs); |
| 936 | |
| 937 | case FUSE_NOTIFY_INVAL_ENTRY: |
| 938 | return fuse_notify_inval_entry(fc, size, cs); |
| 939 | |
| 940 | default: |
| 941 | fuse_copy_finish(cs); |
| 942 | return -EINVAL; |
| 943 | } |
| 944 | } |
| 945 | |
| 946 | /* Look up request on processing list by unique ID */ |
| 947 | static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique) |
| 948 | { |
| 949 | struct list_head *entry; |
| 950 | |
| 951 | list_for_each(entry, &fc->processing) { |
| 952 | struct fuse_req *req; |
| 953 | req = list_entry(entry, struct fuse_req, list); |
| 954 | if (req->in.h.unique == unique || req->intr_unique == unique) |
| 955 | return req; |
| 956 | } |
| 957 | return NULL; |
| 958 | } |
| 959 | |
| 960 | static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out, |
| 961 | unsigned nbytes) |
| 962 | { |
| 963 | unsigned reqsize = sizeof(struct fuse_out_header); |
| 964 | |
| 965 | if (out->h.error) |
| 966 | return nbytes != reqsize ? -EINVAL : 0; |
| 967 | |
| 968 | reqsize += len_args(out->numargs, out->args); |
| 969 | |
| 970 | if (reqsize < nbytes || (reqsize > nbytes && !out->argvar)) |
| 971 | return -EINVAL; |
| 972 | else if (reqsize > nbytes) { |
| 973 | struct fuse_arg *lastarg = &out->args[out->numargs-1]; |
| 974 | unsigned diffsize = reqsize - nbytes; |
| 975 | if (diffsize > lastarg->size) |
| 976 | return -EINVAL; |
| 977 | lastarg->size -= diffsize; |
| 978 | } |
| 979 | return fuse_copy_args(cs, out->numargs, out->argpages, out->args, |
| 980 | out->page_zeroing); |
| 981 | } |
| 982 | |
| 983 | /* |
| 984 | * Write a single reply to a request. First the header is copied from |
| 985 | * the write buffer. The request is then searched on the processing |
| 986 | * list by the unique ID found in the header. If found, then remove |
| 987 | * it from the list and copy the rest of the buffer to the request. |
| 988 | * The request is finished by calling request_end() |
| 989 | */ |
| 990 | static ssize_t fuse_dev_write(struct kiocb *iocb, const struct iovec *iov, |
| 991 | unsigned long nr_segs, loff_t pos) |
| 992 | { |
| 993 | int err; |
| 994 | size_t nbytes = iov_length(iov, nr_segs); |
| 995 | struct fuse_req *req; |
| 996 | struct fuse_out_header oh; |
| 997 | struct fuse_copy_state cs; |
| 998 | struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp); |
| 999 | if (!fc) |
| 1000 | return -EPERM; |
| 1001 | |
| 1002 | fuse_copy_init(&cs, fc, 0, NULL, iov, nr_segs); |
| 1003 | if (nbytes < sizeof(struct fuse_out_header)) |
| 1004 | return -EINVAL; |
| 1005 | |
| 1006 | err = fuse_copy_one(&cs, &oh, sizeof(oh)); |
| 1007 | if (err) |
| 1008 | goto err_finish; |
| 1009 | |
| 1010 | err = -EINVAL; |
| 1011 | if (oh.len != nbytes) |
| 1012 | goto err_finish; |
| 1013 | |
| 1014 | /* |
| 1015 | * Zero oh.unique indicates unsolicited notification message |
| 1016 | * and error contains notification code. |
| 1017 | */ |
| 1018 | if (!oh.unique) { |
| 1019 | err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), &cs); |
| 1020 | return err ? err : nbytes; |
| 1021 | } |
| 1022 | |
| 1023 | err = -EINVAL; |
| 1024 | if (oh.error <= -1000 || oh.error > 0) |
| 1025 | goto err_finish; |
| 1026 | |
| 1027 | spin_lock(&fc->lock); |
| 1028 | err = -ENOENT; |
| 1029 | if (!fc->connected) |
| 1030 | goto err_unlock; |
| 1031 | |
| 1032 | req = request_find(fc, oh.unique); |
| 1033 | if (!req) |
| 1034 | goto err_unlock; |
| 1035 | |
| 1036 | if (req->aborted) { |
| 1037 | spin_unlock(&fc->lock); |
| 1038 | fuse_copy_finish(&cs); |
| 1039 | spin_lock(&fc->lock); |
| 1040 | request_end(fc, req); |
| 1041 | return -ENOENT; |
| 1042 | } |
| 1043 | /* Is it an interrupt reply? */ |
| 1044 | if (req->intr_unique == oh.unique) { |
| 1045 | err = -EINVAL; |
| 1046 | if (nbytes != sizeof(struct fuse_out_header)) |
| 1047 | goto err_unlock; |
| 1048 | |
| 1049 | if (oh.error == -ENOSYS) |
| 1050 | fc->no_interrupt = 1; |
| 1051 | else if (oh.error == -EAGAIN) |
| 1052 | queue_interrupt(fc, req); |
| 1053 | |
| 1054 | spin_unlock(&fc->lock); |
| 1055 | fuse_copy_finish(&cs); |
| 1056 | return nbytes; |
| 1057 | } |
| 1058 | |
| 1059 | req->state = FUSE_REQ_WRITING; |
| 1060 | list_move(&req->list, &fc->io); |
| 1061 | req->out.h = oh; |
| 1062 | req->locked = 1; |
| 1063 | cs.req = req; |
| 1064 | spin_unlock(&fc->lock); |
| 1065 | |
| 1066 | err = copy_out_args(&cs, &req->out, nbytes); |
| 1067 | fuse_copy_finish(&cs); |
| 1068 | |
| 1069 | spin_lock(&fc->lock); |
| 1070 | req->locked = 0; |
| 1071 | if (!err) { |
| 1072 | if (req->aborted) |
| 1073 | err = -ENOENT; |
| 1074 | } else if (!req->aborted) |
| 1075 | req->out.h.error = -EIO; |
| 1076 | request_end(fc, req); |
| 1077 | |
| 1078 | return err ? err : nbytes; |
| 1079 | |
| 1080 | err_unlock: |
| 1081 | spin_unlock(&fc->lock); |
| 1082 | err_finish: |
| 1083 | fuse_copy_finish(&cs); |
| 1084 | return err; |
| 1085 | } |
| 1086 | |
| 1087 | static unsigned fuse_dev_poll(struct file *file, poll_table *wait) |
| 1088 | { |
| 1089 | unsigned mask = POLLOUT | POLLWRNORM; |
| 1090 | struct fuse_conn *fc = fuse_get_conn(file); |
| 1091 | if (!fc) |
| 1092 | return POLLERR; |
| 1093 | |
| 1094 | poll_wait(file, &fc->waitq, wait); |
| 1095 | |
| 1096 | spin_lock(&fc->lock); |
| 1097 | if (!fc->connected) |
| 1098 | mask = POLLERR; |
| 1099 | else if (request_pending(fc)) |
| 1100 | mask |= POLLIN | POLLRDNORM; |
| 1101 | spin_unlock(&fc->lock); |
| 1102 | |
| 1103 | return mask; |
| 1104 | } |
| 1105 | |
| 1106 | /* |
| 1107 | * Abort all requests on the given list (pending or processing) |
| 1108 | * |
| 1109 | * This function releases and reacquires fc->lock |
| 1110 | */ |
| 1111 | static void end_requests(struct fuse_conn *fc, struct list_head *head) |
| 1112 | __releases(&fc->lock) |
| 1113 | __acquires(&fc->lock) |
| 1114 | { |
| 1115 | while (!list_empty(head)) { |
| 1116 | struct fuse_req *req; |
| 1117 | req = list_entry(head->next, struct fuse_req, list); |
| 1118 | req->out.h.error = -ECONNABORTED; |
| 1119 | request_end(fc, req); |
| 1120 | spin_lock(&fc->lock); |
| 1121 | } |
| 1122 | } |
| 1123 | |
| 1124 | /* |
| 1125 | * Abort requests under I/O |
| 1126 | * |
| 1127 | * The requests are set to aborted and finished, and the request |
| 1128 | * waiter is woken up. This will make request_wait_answer() wait |
| 1129 | * until the request is unlocked and then return. |
| 1130 | * |
| 1131 | * If the request is asynchronous, then the end function needs to be |
| 1132 | * called after waiting for the request to be unlocked (if it was |
| 1133 | * locked). |
| 1134 | */ |
| 1135 | static void end_io_requests(struct fuse_conn *fc) |
| 1136 | __releases(&fc->lock) |
| 1137 | __acquires(&fc->lock) |
| 1138 | { |
| 1139 | while (!list_empty(&fc->io)) { |
| 1140 | struct fuse_req *req = |
| 1141 | list_entry(fc->io.next, struct fuse_req, list); |
| 1142 | void (*end) (struct fuse_conn *, struct fuse_req *) = req->end; |
| 1143 | |
| 1144 | req->aborted = 1; |
| 1145 | req->out.h.error = -ECONNABORTED; |
| 1146 | req->state = FUSE_REQ_FINISHED; |
| 1147 | list_del_init(&req->list); |
| 1148 | wake_up(&req->waitq); |
| 1149 | if (end) { |
| 1150 | req->end = NULL; |
| 1151 | __fuse_get_request(req); |
| 1152 | spin_unlock(&fc->lock); |
| 1153 | wait_event(req->waitq, !req->locked); |
| 1154 | end(fc, req); |
| 1155 | fuse_put_request(fc, req); |
| 1156 | spin_lock(&fc->lock); |
| 1157 | } |
| 1158 | } |
| 1159 | } |
| 1160 | |
| 1161 | /* |
| 1162 | * Abort all requests. |
| 1163 | * |
| 1164 | * Emergency exit in case of a malicious or accidental deadlock, or |
| 1165 | * just a hung filesystem. |
| 1166 | * |
| 1167 | * The same effect is usually achievable through killing the |
| 1168 | * filesystem daemon and all users of the filesystem. The exception |
| 1169 | * is the combination of an asynchronous request and the tricky |
| 1170 | * deadlock (see Documentation/filesystems/fuse.txt). |
| 1171 | * |
| 1172 | * During the aborting, progression of requests from the pending and |
| 1173 | * processing lists onto the io list, and progression of new requests |
| 1174 | * onto the pending list is prevented by req->connected being false. |
| 1175 | * |
| 1176 | * Progression of requests under I/O to the processing list is |
| 1177 | * prevented by the req->aborted flag being true for these requests. |
| 1178 | * For this reason requests on the io list must be aborted first. |
| 1179 | */ |
| 1180 | void fuse_abort_conn(struct fuse_conn *fc) |
| 1181 | { |
| 1182 | spin_lock(&fc->lock); |
| 1183 | if (fc->connected) { |
| 1184 | fc->connected = 0; |
| 1185 | fc->blocked = 0; |
| 1186 | end_io_requests(fc); |
| 1187 | end_requests(fc, &fc->pending); |
| 1188 | end_requests(fc, &fc->processing); |
| 1189 | wake_up_all(&fc->waitq); |
| 1190 | wake_up_all(&fc->blocked_waitq); |
| 1191 | kill_fasync(&fc->fasync, SIGIO, POLL_IN); |
| 1192 | } |
| 1193 | spin_unlock(&fc->lock); |
| 1194 | } |
| 1195 | EXPORT_SYMBOL_GPL(fuse_abort_conn); |
| 1196 | |
| 1197 | int fuse_dev_release(struct inode *inode, struct file *file) |
| 1198 | { |
| 1199 | struct fuse_conn *fc = fuse_get_conn(file); |
| 1200 | if (fc) { |
| 1201 | spin_lock(&fc->lock); |
| 1202 | fc->connected = 0; |
| 1203 | end_requests(fc, &fc->pending); |
| 1204 | end_requests(fc, &fc->processing); |
| 1205 | spin_unlock(&fc->lock); |
| 1206 | fuse_conn_put(fc); |
| 1207 | } |
| 1208 | |
| 1209 | return 0; |
| 1210 | } |
| 1211 | EXPORT_SYMBOL_GPL(fuse_dev_release); |
| 1212 | |
| 1213 | static int fuse_dev_fasync(int fd, struct file *file, int on) |
| 1214 | { |
| 1215 | struct fuse_conn *fc = fuse_get_conn(file); |
| 1216 | if (!fc) |
| 1217 | return -EPERM; |
| 1218 | |
| 1219 | /* No locking - fasync_helper does its own locking */ |
| 1220 | return fasync_helper(fd, file, on, &fc->fasync); |
| 1221 | } |
| 1222 | |
| 1223 | const struct file_operations fuse_dev_operations = { |
| 1224 | .owner = THIS_MODULE, |
| 1225 | .llseek = no_llseek, |
| 1226 | .read = do_sync_read, |
| 1227 | .aio_read = fuse_dev_read, |
| 1228 | .write = do_sync_write, |
| 1229 | .aio_write = fuse_dev_write, |
| 1230 | .poll = fuse_dev_poll, |
| 1231 | .release = fuse_dev_release, |
| 1232 | .fasync = fuse_dev_fasync, |
| 1233 | }; |
| 1234 | EXPORT_SYMBOL_GPL(fuse_dev_operations); |
| 1235 | |
| 1236 | static struct miscdevice fuse_miscdevice = { |
| 1237 | .minor = FUSE_MINOR, |
| 1238 | .name = "fuse", |
| 1239 | .fops = &fuse_dev_operations, |
| 1240 | }; |
| 1241 | |
| 1242 | int __init fuse_dev_init(void) |
| 1243 | { |
| 1244 | int err = -ENOMEM; |
| 1245 | fuse_req_cachep = kmem_cache_create("fuse_request", |
| 1246 | sizeof(struct fuse_req), |
| 1247 | 0, 0, NULL); |
| 1248 | if (!fuse_req_cachep) |
| 1249 | goto out; |
| 1250 | |
| 1251 | err = misc_register(&fuse_miscdevice); |
| 1252 | if (err) |
| 1253 | goto out_cache_clean; |
| 1254 | |
| 1255 | return 0; |
| 1256 | |
| 1257 | out_cache_clean: |
| 1258 | kmem_cache_destroy(fuse_req_cachep); |
| 1259 | out: |
| 1260 | return err; |
| 1261 | } |
| 1262 | |
| 1263 | void fuse_dev_cleanup(void) |
| 1264 | { |
| 1265 | misc_deregister(&fuse_miscdevice); |
| 1266 | kmem_cache_destroy(fuse_req_cachep); |
| 1267 | } |