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#include <linux/pipe_fs_i.h>
  20#include <linux/swap.h>
  21#include <linux/splice.h>
 
  22
  23MODULE_ALIAS_MISCDEV(FUSE_MINOR);
  24MODULE_ALIAS("devname:fuse");
  25
 
 
 
 
  26static struct kmem_cache *fuse_req_cachep;
  27
  28static struct fuse_dev *fuse_get_dev(struct file *file)
  29{
  30	/*
  31	 * Lockless access is OK, because file->private data is set
  32	 * once during mount and is valid until the file is released.
  33	 */
  34	return ACCESS_ONCE(file->private_data);
  35}
  36
  37static void fuse_request_init(struct fuse_req *req, struct page **pages,
  38			      struct fuse_page_desc *page_descs,
  39			      unsigned npages)
  40{
  41	memset(req, 0, sizeof(*req));
  42	memset(pages, 0, sizeof(*pages) * npages);
  43	memset(page_descs, 0, sizeof(*page_descs) * npages);
  44	INIT_LIST_HEAD(&req->list);
  45	INIT_LIST_HEAD(&req->intr_entry);
  46	init_waitqueue_head(&req->waitq);
  47	atomic_set(&req->count, 1);
  48	req->pages = pages;
  49	req->page_descs = page_descs;
  50	req->max_pages = npages;
  51	__set_bit(FR_PENDING, &req->flags);
 
  52}
  53
  54static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags)
  55{
  56	struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, flags);
  57	if (req) {
  58		struct page **pages;
  59		struct fuse_page_desc *page_descs;
  60
  61		if (npages <= FUSE_REQ_INLINE_PAGES) {
  62			pages = req->inline_pages;
  63			page_descs = req->inline_page_descs;
  64		} else {
  65			pages = kmalloc(sizeof(struct page *) * npages, flags);
  66			page_descs = kmalloc(sizeof(struct fuse_page_desc) *
  67					     npages, flags);
  68		}
  69
  70		if (!pages || !page_descs) {
  71			kfree(pages);
  72			kfree(page_descs);
  73			kmem_cache_free(fuse_req_cachep, req);
  74			return NULL;
  75		}
  76
  77		fuse_request_init(req, pages, page_descs, npages);
  78	}
  79	return req;
  80}
  81
  82struct fuse_req *fuse_request_alloc(unsigned npages)
  83{
  84	return __fuse_request_alloc(npages, GFP_KERNEL);
  85}
  86EXPORT_SYMBOL_GPL(fuse_request_alloc);
  87
  88struct fuse_req *fuse_request_alloc_nofs(unsigned npages)
  89{
  90	return __fuse_request_alloc(npages, GFP_NOFS);
  91}
  92
  93void fuse_request_free(struct fuse_req *req)
  94{
  95	if (req->pages != req->inline_pages) {
  96		kfree(req->pages);
  97		kfree(req->page_descs);
  98	}
  99	kmem_cache_free(fuse_req_cachep, req);
 100}
 101
 102void __fuse_get_request(struct fuse_req *req)
 103{
 104	atomic_inc(&req->count);
 105}
 106
 107/* Must be called with > 1 refcount */
 108static void __fuse_put_request(struct fuse_req *req)
 109{
 110	BUG_ON(atomic_read(&req->count) < 2);
 111	atomic_dec(&req->count);
 112}
 113
 114static void fuse_req_init_context(struct fuse_req *req)
 115{
 116	req->in.h.uid = from_kuid_munged(&init_user_ns, current_fsuid());
 117	req->in.h.gid = from_kgid_munged(&init_user_ns, current_fsgid());
 118	req->in.h.pid = current->pid;
 119}
 120
 121void fuse_set_initialized(struct fuse_conn *fc)
 122{
 123	/* Make sure stores before this are seen on another CPU */
 124	smp_wmb();
 125	fc->initialized = 1;
 126}
 127
 128static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
 129{
 130	return !fc->initialized || (for_background && fc->blocked);
 131}
 132
 133static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
 134				       bool for_background)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 135{
 
 136	struct fuse_req *req;
 137	int err;
 138	atomic_inc(&fc->num_waiting);
 139
 140	if (fuse_block_alloc(fc, for_background)) {
 141		err = -EINTR;
 142		if (wait_event_killable_exclusive(fc->blocked_waitq,
 143				!fuse_block_alloc(fc, for_background)))
 144			goto out;
 145	}
 146	/* Matches smp_wmb() in fuse_set_initialized() */
 147	smp_rmb();
 148
 149	err = -ENOTCONN;
 150	if (!fc->connected)
 151		goto out;
 152
 153	err = -ECONNREFUSED;
 154	if (fc->conn_error)
 155		goto out;
 156
 157	req = fuse_request_alloc(npages);
 158	err = -ENOMEM;
 159	if (!req) {
 160		if (for_background)
 161			wake_up(&fc->blocked_waitq);
 162		goto out;
 163	}
 164
 165	fuse_req_init_context(req);
 
 
 
 166	__set_bit(FR_WAITING, &req->flags);
 167	if (for_background)
 168		__set_bit(FR_BACKGROUND, &req->flags);
 169
 
 
 
 
 
 170	return req;
 171
 172 out:
 173	atomic_dec(&fc->num_waiting);
 174	return ERR_PTR(err);
 175}
 176
 177struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages)
 178{
 179	return __fuse_get_req(fc, npages, false);
 180}
 181EXPORT_SYMBOL_GPL(fuse_get_req);
 182
 183struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
 184					     unsigned npages)
 185{
 186	return __fuse_get_req(fc, npages, true);
 187}
 188EXPORT_SYMBOL_GPL(fuse_get_req_for_background);
 189
 190/*
 191 * Return request in fuse_file->reserved_req.  However that may
 192 * currently be in use.  If that is the case, wait for it to become
 193 * available.
 194 */
 195static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
 196					 struct file *file)
 197{
 198	struct fuse_req *req = NULL;
 199	struct fuse_file *ff = file->private_data;
 200
 201	do {
 202		wait_event(fc->reserved_req_waitq, ff->reserved_req);
 203		spin_lock(&fc->lock);
 204		if (ff->reserved_req) {
 205			req = ff->reserved_req;
 206			ff->reserved_req = NULL;
 207			req->stolen_file = get_file(file);
 208		}
 209		spin_unlock(&fc->lock);
 210	} while (!req);
 211
 212	return req;
 213}
 214
 215/*
 216 * Put stolen request back into fuse_file->reserved_req
 217 */
 218static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
 219{
 220	struct file *file = req->stolen_file;
 221	struct fuse_file *ff = file->private_data;
 222
 223	spin_lock(&fc->lock);
 224	fuse_request_init(req, req->pages, req->page_descs, req->max_pages);
 225	BUG_ON(ff->reserved_req);
 226	ff->reserved_req = req;
 227	wake_up_all(&fc->reserved_req_waitq);
 228	spin_unlock(&fc->lock);
 229	fput(file);
 230}
 231
 232/*
 233 * Gets a requests for a file operation, always succeeds
 234 *
 235 * This is used for sending the FLUSH request, which must get to
 236 * userspace, due to POSIX locks which may need to be unlocked.
 237 *
 238 * If allocation fails due to OOM, use the reserved request in
 239 * fuse_file.
 240 *
 241 * This is very unlikely to deadlock accidentally, since the
 242 * filesystem should not have it's own file open.  If deadlock is
 243 * intentional, it can still be broken by "aborting" the filesystem.
 244 */
 245struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
 246					     struct file *file)
 247{
 248	struct fuse_req *req;
 249
 250	atomic_inc(&fc->num_waiting);
 251	wait_event(fc->blocked_waitq, fc->initialized);
 252	/* Matches smp_wmb() in fuse_set_initialized() */
 253	smp_rmb();
 254	req = fuse_request_alloc(0);
 255	if (!req)
 256		req = get_reserved_req(fc, file);
 257
 258	fuse_req_init_context(req);
 259	__set_bit(FR_WAITING, &req->flags);
 260	__clear_bit(FR_BACKGROUND, &req->flags);
 261	return req;
 262}
 263
 264void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
 265{
 266	if (atomic_dec_and_test(&req->count)) {
 267		if (test_bit(FR_BACKGROUND, &req->flags)) {
 268			/*
 269			 * We get here in the unlikely case that a background
 270			 * request was allocated but not sent
 271			 */
 272			spin_lock(&fc->lock);
 273			if (!fc->blocked)
 274				wake_up(&fc->blocked_waitq);
 275			spin_unlock(&fc->lock);
 276		}
 277
 278		if (test_bit(FR_WAITING, &req->flags)) {
 279			__clear_bit(FR_WAITING, &req->flags);
 280			atomic_dec(&fc->num_waiting);
 281		}
 282
 283		if (req->stolen_file)
 284			put_reserved_req(fc, req);
 285		else
 286			fuse_request_free(req);
 287	}
 288}
 289EXPORT_SYMBOL_GPL(fuse_put_request);
 290
 291static unsigned len_args(unsigned numargs, struct fuse_arg *args)
 292{
 293	unsigned nbytes = 0;
 294	unsigned i;
 295
 296	for (i = 0; i < numargs; i++)
 297		nbytes += args[i].size;
 298
 299	return nbytes;
 300}
 
 301
 302static u64 fuse_get_unique(struct fuse_iqueue *fiq)
 303{
 304	return ++fiq->reqctr;
 
 305}
 
 306
 307static void queue_request(struct fuse_iqueue *fiq, struct fuse_req *req)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 308{
 309	req->in.h.len = sizeof(struct fuse_in_header) +
 310		len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
 
 311	list_add_tail(&req->list, &fiq->pending);
 312	wake_up_locked(&fiq->waitq);
 313	kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
 314}
 315
 316void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
 317		       u64 nodeid, u64 nlookup)
 318{
 319	struct fuse_iqueue *fiq = &fc->iq;
 320
 321	forget->forget_one.nodeid = nodeid;
 322	forget->forget_one.nlookup = nlookup;
 323
 324	spin_lock(&fiq->waitq.lock);
 325	if (fiq->connected) {
 326		fiq->forget_list_tail->next = forget;
 327		fiq->forget_list_tail = forget;
 328		wake_up_locked(&fiq->waitq);
 329		kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
 330	} else {
 331		kfree(forget);
 
 332	}
 333	spin_unlock(&fiq->waitq.lock);
 334}
 335
 336static void flush_bg_queue(struct fuse_conn *fc)
 337{
 
 
 338	while (fc->active_background < fc->max_background &&
 339	       !list_empty(&fc->bg_queue)) {
 340		struct fuse_req *req;
 341		struct fuse_iqueue *fiq = &fc->iq;
 342
 343		req = list_entry(fc->bg_queue.next, struct fuse_req, list);
 344		list_del(&req->list);
 345		fc->active_background++;
 346		spin_lock(&fiq->waitq.lock);
 347		req->in.h.unique = fuse_get_unique(fiq);
 348		queue_request(fiq, req);
 349		spin_unlock(&fiq->waitq.lock);
 350	}
 351}
 352
 353/*
 354 * This function is called when a request is finished.  Either a reply
 355 * has arrived or it was aborted (and not yet sent) or some error
 356 * occurred during communication with userspace, or the device file
 357 * was closed.  The requester thread is woken up (if still waiting),
 358 * the 'end' callback is called if given, else the reference to the
 359 * request is released
 360 */
 361static void request_end(struct fuse_conn *fc, struct fuse_req *req)
 362{
 
 
 363	struct fuse_iqueue *fiq = &fc->iq;
 364
 365	if (test_and_set_bit(FR_FINISHED, &req->flags))
 366		return;
 367
 368	spin_lock(&fiq->waitq.lock);
 369	list_del_init(&req->intr_entry);
 370	spin_unlock(&fiq->waitq.lock);
 
 
 
 
 
 
 
 371	WARN_ON(test_bit(FR_PENDING, &req->flags));
 372	WARN_ON(test_bit(FR_SENT, &req->flags));
 373	if (test_bit(FR_BACKGROUND, &req->flags)) {
 374		spin_lock(&fc->lock);
 375		clear_bit(FR_BACKGROUND, &req->flags);
 376		if (fc->num_background == fc->max_background)
 377			fc->blocked = 0;
 378
 379		/* Wake up next waiter, if any */
 380		if (!fc->blocked && waitqueue_active(&fc->blocked_waitq))
 381			wake_up(&fc->blocked_waitq);
 382
 383		if (fc->num_background == fc->congestion_threshold &&
 384		    fc->connected && fc->bdi_initialized) {
 385			clear_bdi_congested(&fc->bdi, BLK_RW_SYNC);
 386			clear_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
 
 
 
 
 387		}
 
 388		fc->num_background--;
 389		fc->active_background--;
 390		flush_bg_queue(fc);
 391		spin_unlock(&fc->lock);
 
 
 
 392	}
 393	wake_up(&req->waitq);
 394	if (req->end)
 395		req->end(fc, req);
 396	fuse_put_request(fc, req);
 
 397}
 
 398
 399static void queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
 400{
 401	spin_lock(&fiq->waitq.lock);
 402	if (test_bit(FR_FINISHED, &req->flags)) {
 403		spin_unlock(&fiq->waitq.lock);
 404		return;
 
 
 
 405	}
 
 406	if (list_empty(&req->intr_entry)) {
 407		list_add_tail(&req->intr_entry, &fiq->interrupts);
 408		wake_up_locked(&fiq->waitq);
 
 
 
 
 
 
 
 
 
 
 
 
 409	}
 410	spin_unlock(&fiq->waitq.lock);
 411	kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
 412}
 413
 414static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
 415{
 
 416	struct fuse_iqueue *fiq = &fc->iq;
 417	int err;
 418
 419	if (!fc->no_interrupt) {
 420		/* Any signal may interrupt this */
 421		err = wait_event_interruptible(req->waitq,
 422					test_bit(FR_FINISHED, &req->flags));
 423		if (!err)
 424			return;
 425
 426		set_bit(FR_INTERRUPTED, &req->flags);
 427		/* matches barrier in fuse_dev_do_read() */
 428		smp_mb__after_atomic();
 429		if (test_bit(FR_SENT, &req->flags))
 430			queue_interrupt(fiq, req);
 431	}
 432
 433	if (!test_bit(FR_FORCE, &req->flags)) {
 434		/* Only fatal signals may interrupt this */
 435		err = wait_event_killable(req->waitq,
 436					test_bit(FR_FINISHED, &req->flags));
 437		if (!err)
 438			return;
 439
 440		spin_lock(&fiq->waitq.lock);
 441		/* Request is not yet in userspace, bail out */
 442		if (test_bit(FR_PENDING, &req->flags)) {
 443			list_del(&req->list);
 444			spin_unlock(&fiq->waitq.lock);
 445			__fuse_put_request(req);
 446			req->out.h.error = -EINTR;
 447			return;
 448		}
 449		spin_unlock(&fiq->waitq.lock);
 450	}
 451
 452	/*
 453	 * Either request is already in userspace, or it was forced.
 454	 * Wait it out.
 455	 */
 456	wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags));
 457}
 458
 459static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
 460{
 461	struct fuse_iqueue *fiq = &fc->iq;
 462
 463	BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
 464	spin_lock(&fiq->waitq.lock);
 465	if (!fiq->connected) {
 466		spin_unlock(&fiq->waitq.lock);
 467		req->out.h.error = -ENOTCONN;
 468	} else {
 469		req->in.h.unique = fuse_get_unique(fiq);
 470		queue_request(fiq, req);
 471		/* acquire extra reference, since request is still needed
 472		   after request_end() */
 473		__fuse_get_request(req);
 474		spin_unlock(&fiq->waitq.lock);
 475
 476		request_wait_answer(fc, req);
 477		/* Pairs with smp_wmb() in request_end() */
 478		smp_rmb();
 479	}
 480}
 481
 482void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
 483{
 484	__set_bit(FR_ISREPLY, &req->flags);
 485	if (!test_bit(FR_WAITING, &req->flags)) {
 486		__set_bit(FR_WAITING, &req->flags);
 487		atomic_inc(&fc->num_waiting);
 488	}
 489	__fuse_request_send(fc, req);
 490}
 491EXPORT_SYMBOL_GPL(fuse_request_send);
 492
 493static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
 494{
 495	if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS)
 496		args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE;
 497
 498	if (fc->minor < 9) {
 499		switch (args->in.h.opcode) {
 500		case FUSE_LOOKUP:
 501		case FUSE_CREATE:
 502		case FUSE_MKNOD:
 503		case FUSE_MKDIR:
 504		case FUSE_SYMLINK:
 505		case FUSE_LINK:
 506			args->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
 507			break;
 508		case FUSE_GETATTR:
 509		case FUSE_SETATTR:
 510			args->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
 511			break;
 512		}
 513	}
 514	if (fc->minor < 12) {
 515		switch (args->in.h.opcode) {
 516		case FUSE_CREATE:
 517			args->in.args[0].size = sizeof(struct fuse_open_in);
 518			break;
 519		case FUSE_MKNOD:
 520			args->in.args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
 521			break;
 522		}
 523	}
 524}
 525
 526ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
 527{
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 528	struct fuse_req *req;
 529	ssize_t ret;
 530
 531	req = fuse_get_req(fc, 0);
 532	if (IS_ERR(req))
 533		return PTR_ERR(req);
 
 
 
 
 
 
 
 
 
 
 
 
 534
 535	/* Needs to be done after fuse_get_req() so that fc->minor is valid */
 536	fuse_adjust_compat(fc, args);
 
 537
 538	req->in.h.opcode = args->in.h.opcode;
 539	req->in.h.nodeid = args->in.h.nodeid;
 540	req->in.numargs = args->in.numargs;
 541	memcpy(req->in.args, args->in.args,
 542	       args->in.numargs * sizeof(struct fuse_in_arg));
 543	req->out.argvar = args->out.argvar;
 544	req->out.numargs = args->out.numargs;
 545	memcpy(req->out.args, args->out.args,
 546	       args->out.numargs * sizeof(struct fuse_arg));
 547	fuse_request_send(fc, req);
 548	ret = req->out.h.error;
 549	if (!ret && args->out.argvar) {
 550		BUG_ON(args->out.numargs != 1);
 551		ret = req->out.args[0].size;
 552	}
 553	fuse_put_request(fc, req);
 554
 555	return ret;
 556}
 557
 558/*
 559 * Called under fc->lock
 560 *
 561 * fc->connected must have been checked previously
 562 */
 563void fuse_request_send_background_locked(struct fuse_conn *fc,
 564					 struct fuse_req *req)
 565{
 566	BUG_ON(!test_bit(FR_BACKGROUND, &req->flags));
 
 
 
 
 567	if (!test_bit(FR_WAITING, &req->flags)) {
 568		__set_bit(FR_WAITING, &req->flags);
 569		atomic_inc(&fc->num_waiting);
 570	}
 571	__set_bit(FR_ISREPLY, &req->flags);
 572	fc->num_background++;
 573	if (fc->num_background == fc->max_background)
 574		fc->blocked = 1;
 575	if (fc->num_background == fc->congestion_threshold &&
 576	    fc->bdi_initialized) {
 577		set_bdi_congested(&fc->bdi, BLK_RW_SYNC);
 578		set_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
 
 579	}
 580	list_add_tail(&req->list, &fc->bg_queue);
 581	flush_bg_queue(fc);
 
 582}
 583
 584void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
 
 585{
 586	BUG_ON(!req->end);
 587	spin_lock(&fc->lock);
 588	if (fc->connected) {
 589		fuse_request_send_background_locked(fc, req);
 590		spin_unlock(&fc->lock);
 
 
 
 591	} else {
 592		spin_unlock(&fc->lock);
 593		req->out.h.error = -ENOTCONN;
 594		req->end(fc, req);
 595		fuse_put_request(fc, req);
 596	}
 597}
 598EXPORT_SYMBOL_GPL(fuse_request_send_background);
 599
 600static int fuse_request_send_notify_reply(struct fuse_conn *fc,
 601					  struct fuse_req *req, u64 unique)
 602{
 603	int err = -ENODEV;
 604	struct fuse_iqueue *fiq = &fc->iq;
 605
 606	__clear_bit(FR_ISREPLY, &req->flags);
 607	req->in.h.unique = unique;
 608	spin_lock(&fiq->waitq.lock);
 609	if (fiq->connected) {
 610		queue_request(fiq, req);
 611		err = 0;
 612	}
 613	spin_unlock(&fiq->waitq.lock);
 614
 615	return err;
 616}
 
 617
 618void fuse_force_forget(struct file *file, u64 nodeid)
 
 619{
 620	struct inode *inode = file_inode(file);
 621	struct fuse_conn *fc = get_fuse_conn(inode);
 622	struct fuse_req *req;
 623	struct fuse_forget_in inarg;
 
 
 
 
 
 624
 625	memset(&inarg, 0, sizeof(inarg));
 626	inarg.nlookup = 1;
 627	req = fuse_get_req_nofail_nopages(fc, file);
 628	req->in.h.opcode = FUSE_FORGET;
 629	req->in.h.nodeid = nodeid;
 630	req->in.numargs = 1;
 631	req->in.args[0].size = sizeof(inarg);
 632	req->in.args[0].value = &inarg;
 633	__clear_bit(FR_ISREPLY, &req->flags);
 634	__fuse_request_send(fc, req);
 635	/* ignore errors */
 636	fuse_put_request(fc, req);
 
 
 
 
 
 
 
 
 
 
 
 637}
 638
 639/*
 640 * Lock the request.  Up to the next unlock_request() there mustn't be
 641 * anything that could cause a page-fault.  If the request was already
 642 * aborted bail out.
 643 */
 644static int lock_request(struct fuse_req *req)
 645{
 646	int err = 0;
 647	if (req) {
 648		spin_lock(&req->waitq.lock);
 649		if (test_bit(FR_ABORTED, &req->flags))
 650			err = -ENOENT;
 651		else
 652			set_bit(FR_LOCKED, &req->flags);
 653		spin_unlock(&req->waitq.lock);
 654	}
 655	return err;
 656}
 657
 658/*
 659 * Unlock request.  If it was aborted while locked, caller is responsible
 660 * for unlocking and ending the request.
 661 */
 662static int unlock_request(struct fuse_req *req)
 663{
 664	int err = 0;
 665	if (req) {
 666		spin_lock(&req->waitq.lock);
 667		if (test_bit(FR_ABORTED, &req->flags))
 668			err = -ENOENT;
 669		else
 670			clear_bit(FR_LOCKED, &req->flags);
 671		spin_unlock(&req->waitq.lock);
 672	}
 673	return err;
 674}
 675
 676struct fuse_copy_state {
 677	int write;
 678	struct fuse_req *req;
 679	struct iov_iter *iter;
 680	struct pipe_buffer *pipebufs;
 681	struct pipe_buffer *currbuf;
 682	struct pipe_inode_info *pipe;
 683	unsigned long nr_segs;
 684	struct page *pg;
 685	unsigned len;
 686	unsigned offset;
 687	unsigned move_pages:1;
 688};
 689
 690static void fuse_copy_init(struct fuse_copy_state *cs, int write,
 691			   struct iov_iter *iter)
 692{
 693	memset(cs, 0, sizeof(*cs));
 694	cs->write = write;
 695	cs->iter = iter;
 696}
 697
 698/* Unmap and put previous page of userspace buffer */
 699static void fuse_copy_finish(struct fuse_copy_state *cs)
 700{
 701	if (cs->currbuf) {
 702		struct pipe_buffer *buf = cs->currbuf;
 703
 704		if (cs->write)
 705			buf->len = PAGE_SIZE - cs->len;
 706		cs->currbuf = NULL;
 707	} else if (cs->pg) {
 708		if (cs->write) {
 709			flush_dcache_page(cs->pg);
 710			set_page_dirty_lock(cs->pg);
 711		}
 712		put_page(cs->pg);
 713	}
 714	cs->pg = NULL;
 715}
 716
 717/*
 718 * Get another pagefull of userspace buffer, and map it to kernel
 719 * address space, and lock request
 720 */
 721static int fuse_copy_fill(struct fuse_copy_state *cs)
 722{
 723	struct page *page;
 724	int err;
 725
 726	err = unlock_request(cs->req);
 727	if (err)
 728		return err;
 729
 730	fuse_copy_finish(cs);
 731	if (cs->pipebufs) {
 732		struct pipe_buffer *buf = cs->pipebufs;
 733
 734		if (!cs->write) {
 735			err = pipe_buf_confirm(cs->pipe, buf);
 736			if (err)
 737				return err;
 738
 739			BUG_ON(!cs->nr_segs);
 740			cs->currbuf = buf;
 741			cs->pg = buf->page;
 742			cs->offset = buf->offset;
 743			cs->len = buf->len;
 744			cs->pipebufs++;
 745			cs->nr_segs--;
 746		} else {
 747			if (cs->nr_segs == cs->pipe->buffers)
 748				return -EIO;
 749
 750			page = alloc_page(GFP_HIGHUSER);
 751			if (!page)
 752				return -ENOMEM;
 753
 754			buf->page = page;
 755			buf->offset = 0;
 756			buf->len = 0;
 757
 758			cs->currbuf = buf;
 759			cs->pg = page;
 760			cs->offset = 0;
 761			cs->len = PAGE_SIZE;
 762			cs->pipebufs++;
 763			cs->nr_segs++;
 764		}
 765	} else {
 766		size_t off;
 767		err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off);
 768		if (err < 0)
 769			return err;
 770		BUG_ON(!err);
 771		cs->len = err;
 772		cs->offset = off;
 773		cs->pg = page;
 774		iov_iter_advance(cs->iter, err);
 775	}
 776
 777	return lock_request(cs->req);
 778}
 779
 780/* Do as much copy to/from userspace buffer as we can */
 781static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
 782{
 783	unsigned ncpy = min(*size, cs->len);
 784	if (val) {
 785		void *pgaddr = kmap_atomic(cs->pg);
 786		void *buf = pgaddr + cs->offset;
 787
 788		if (cs->write)
 789			memcpy(buf, *val, ncpy);
 790		else
 791			memcpy(*val, buf, ncpy);
 792
 793		kunmap_atomic(pgaddr);
 794		*val += ncpy;
 795	}
 796	*size -= ncpy;
 797	cs->len -= ncpy;
 798	cs->offset += ncpy;
 799	return ncpy;
 800}
 801
 802static int fuse_check_page(struct page *page)
 803{
 804	if (page_mapcount(page) ||
 805	    page->mapping != NULL ||
 806	    page_count(page) != 1 ||
 807	    (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
 808	     ~(1 << PG_locked |
 809	       1 << PG_referenced |
 810	       1 << PG_uptodate |
 811	       1 << PG_lru |
 812	       1 << PG_active |
 813	       1 << PG_reclaim))) {
 814		printk(KERN_WARNING "fuse: trying to steal weird page\n");
 815		printk(KERN_WARNING "  page=%p index=%li flags=%08lx, count=%i, mapcount=%i, mapping=%p\n", page, page->index, page->flags, page_count(page), page_mapcount(page), page->mapping);
 
 
 816		return 1;
 817	}
 818	return 0;
 819}
 820
 821static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 822{
 823	int err;
 824	struct page *oldpage = *pagep;
 825	struct page *newpage;
 826	struct pipe_buffer *buf = cs->pipebufs;
 827
 
 828	err = unlock_request(cs->req);
 829	if (err)
 830		return err;
 831
 832	fuse_copy_finish(cs);
 833
 834	err = pipe_buf_confirm(cs->pipe, buf);
 835	if (err)
 836		return err;
 837
 838	BUG_ON(!cs->nr_segs);
 839	cs->currbuf = buf;
 840	cs->len = buf->len;
 841	cs->pipebufs++;
 842	cs->nr_segs--;
 843
 844	if (cs->len != PAGE_SIZE)
 845		goto out_fallback;
 846
 847	if (pipe_buf_steal(cs->pipe, buf) != 0)
 848		goto out_fallback;
 849
 850	newpage = buf->page;
 851
 852	if (!PageUptodate(newpage))
 853		SetPageUptodate(newpage);
 854
 855	ClearPageMappedToDisk(newpage);
 856
 857	if (fuse_check_page(newpage) != 0)
 858		goto out_fallback_unlock;
 859
 860	/*
 861	 * This is a new and locked page, it shouldn't be mapped or
 862	 * have any special flags on it
 863	 */
 864	if (WARN_ON(page_mapped(oldpage)))
 865		goto out_fallback_unlock;
 866	if (WARN_ON(page_has_private(oldpage)))
 867		goto out_fallback_unlock;
 868	if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
 
 869		goto out_fallback_unlock;
 870	if (WARN_ON(PageMlocked(oldpage)))
 871		goto out_fallback_unlock;
 872
 873	err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
 874	if (err) {
 875		unlock_page(newpage);
 876		return err;
 877	}
 878
 879	get_page(newpage);
 880
 881	if (!(buf->flags & PIPE_BUF_FLAG_LRU))
 882		lru_cache_add_file(newpage);
 
 
 
 
 
 
 883
 884	err = 0;
 885	spin_lock(&cs->req->waitq.lock);
 886	if (test_bit(FR_ABORTED, &cs->req->flags))
 887		err = -ENOENT;
 888	else
 889		*pagep = newpage;
 890	spin_unlock(&cs->req->waitq.lock);
 891
 892	if (err) {
 893		unlock_page(newpage);
 894		put_page(newpage);
 895		return err;
 896	}
 897
 898	unlock_page(oldpage);
 899	put_page(oldpage);
 
 900	cs->len = 0;
 901
 902	return 0;
 
 
 
 
 903
 904out_fallback_unlock:
 905	unlock_page(newpage);
 906out_fallback:
 907	cs->pg = buf->page;
 908	cs->offset = buf->offset;
 909
 910	err = lock_request(cs->req);
 911	if (err)
 912		return err;
 913
 914	return 1;
 915}
 916
 917static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
 918			 unsigned offset, unsigned count)
 919{
 920	struct pipe_buffer *buf;
 921	int err;
 922
 923	if (cs->nr_segs == cs->pipe->buffers)
 924		return -EIO;
 925
 
 926	err = unlock_request(cs->req);
 927	if (err)
 
 928		return err;
 
 929
 930	fuse_copy_finish(cs);
 931
 932	buf = cs->pipebufs;
 933	get_page(page);
 934	buf->page = page;
 935	buf->offset = offset;
 936	buf->len = count;
 937
 938	cs->pipebufs++;
 939	cs->nr_segs++;
 940	cs->len = 0;
 941
 942	return 0;
 943}
 944
 945/*
 946 * Copy a page in the request to/from the userspace buffer.  Must be
 947 * done atomically
 948 */
 949static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
 950			  unsigned offset, unsigned count, int zeroing)
 951{
 952	int err;
 953	struct page *page = *pagep;
 954
 955	if (page && zeroing && count < PAGE_SIZE)
 956		clear_highpage(page);
 957
 958	while (count) {
 959		if (cs->write && cs->pipebufs && page) {
 960			return fuse_ref_page(cs, page, offset, count);
 
 
 
 
 
 
 
 
 
 
 961		} else if (!cs->len) {
 962			if (cs->move_pages && page &&
 963			    offset == 0 && count == PAGE_SIZE) {
 964				err = fuse_try_move_page(cs, pagep);
 965				if (err <= 0)
 966					return err;
 967			} else {
 968				err = fuse_copy_fill(cs);
 969				if (err)
 970					return err;
 971			}
 972		}
 973		if (page) {
 974			void *mapaddr = kmap_atomic(page);
 975			void *buf = mapaddr + offset;
 976			offset += fuse_copy_do(cs, &buf, &count);
 977			kunmap_atomic(mapaddr);
 978		} else
 979			offset += fuse_copy_do(cs, NULL, &count);
 980	}
 981	if (page && !cs->write)
 982		flush_dcache_page(page);
 983	return 0;
 984}
 985
 986/* Copy pages in the request to/from userspace buffer */
 987static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
 988			   int zeroing)
 989{
 990	unsigned i;
 991	struct fuse_req *req = cs->req;
 
 992
 993	for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
 
 994		int err;
 995		unsigned offset = req->page_descs[i].offset;
 996		unsigned count = min(nbytes, req->page_descs[i].length);
 997
 998		err = fuse_copy_page(cs, &req->pages[i], offset, count,
 999				     zeroing);
1000		if (err)
1001			return err;
1002
1003		nbytes -= count;
1004	}
1005	return 0;
1006}
1007
1008/* Copy a single argument in the request to/from userspace buffer */
1009static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
1010{
1011	while (size) {
1012		if (!cs->len) {
1013			int err = fuse_copy_fill(cs);
1014			if (err)
1015				return err;
1016		}
1017		fuse_copy_do(cs, &val, &size);
1018	}
1019	return 0;
1020}
1021
1022/* Copy request arguments to/from userspace buffer */
1023static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1024			  unsigned argpages, struct fuse_arg *args,
1025			  int zeroing)
1026{
1027	int err = 0;
1028	unsigned i;
1029
1030	for (i = 0; !err && i < numargs; i++)  {
1031		struct fuse_arg *arg = &args[i];
1032		if (i == numargs - 1 && argpages)
1033			err = fuse_copy_pages(cs, arg->size, zeroing);
1034		else
1035			err = fuse_copy_one(cs, arg->value, arg->size);
1036	}
1037	return err;
1038}
1039
1040static int forget_pending(struct fuse_iqueue *fiq)
1041{
1042	return fiq->forget_list_head.next != NULL;
1043}
1044
1045static int request_pending(struct fuse_iqueue *fiq)
1046{
1047	return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1048		forget_pending(fiq);
1049}
1050
1051/*
1052 * Transfer an interrupt request to userspace
1053 *
1054 * Unlike other requests this is assembled on demand, without a need
1055 * to allocate a separate fuse_req structure.
1056 *
1057 * Called with fiq->waitq.lock held, releases it
1058 */
1059static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1060			       struct fuse_copy_state *cs,
1061			       size_t nbytes, struct fuse_req *req)
1062__releases(fiq->waitq.lock)
1063{
1064	struct fuse_in_header ih;
1065	struct fuse_interrupt_in arg;
1066	unsigned reqsize = sizeof(ih) + sizeof(arg);
1067	int err;
1068
1069	list_del_init(&req->intr_entry);
1070	req->intr_unique = fuse_get_unique(fiq);
1071	memset(&ih, 0, sizeof(ih));
1072	memset(&arg, 0, sizeof(arg));
1073	ih.len = reqsize;
1074	ih.opcode = FUSE_INTERRUPT;
1075	ih.unique = req->intr_unique;
1076	arg.unique = req->in.h.unique;
1077
1078	spin_unlock(&fiq->waitq.lock);
1079	if (nbytes < reqsize)
1080		return -EINVAL;
1081
1082	err = fuse_copy_one(cs, &ih, sizeof(ih));
1083	if (!err)
1084		err = fuse_copy_one(cs, &arg, sizeof(arg));
1085	fuse_copy_finish(cs);
1086
1087	return err ? err : reqsize;
1088}
1089
1090static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq,
1091					       unsigned max,
1092					       unsigned *countp)
1093{
1094	struct fuse_forget_link *head = fiq->forget_list_head.next;
1095	struct fuse_forget_link **newhead = &head;
1096	unsigned count;
1097
1098	for (count = 0; *newhead != NULL && count < max; count++)
1099		newhead = &(*newhead)->next;
1100
1101	fiq->forget_list_head.next = *newhead;
1102	*newhead = NULL;
1103	if (fiq->forget_list_head.next == NULL)
1104		fiq->forget_list_tail = &fiq->forget_list_head;
1105
1106	if (countp != NULL)
1107		*countp = count;
1108
1109	return head;
1110}
 
1111
1112static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1113				   struct fuse_copy_state *cs,
1114				   size_t nbytes)
1115__releases(fiq->waitq.lock)
1116{
1117	int err;
1118	struct fuse_forget_link *forget = dequeue_forget(fiq, 1, NULL);
1119	struct fuse_forget_in arg = {
1120		.nlookup = forget->forget_one.nlookup,
1121	};
1122	struct fuse_in_header ih = {
1123		.opcode = FUSE_FORGET,
1124		.nodeid = forget->forget_one.nodeid,
1125		.unique = fuse_get_unique(fiq),
1126		.len = sizeof(ih) + sizeof(arg),
1127	};
1128
1129	spin_unlock(&fiq->waitq.lock);
1130	kfree(forget);
1131	if (nbytes < ih.len)
1132		return -EINVAL;
1133
1134	err = fuse_copy_one(cs, &ih, sizeof(ih));
1135	if (!err)
1136		err = fuse_copy_one(cs, &arg, sizeof(arg));
1137	fuse_copy_finish(cs);
1138
1139	if (err)
1140		return err;
1141
1142	return ih.len;
1143}
1144
1145static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1146				   struct fuse_copy_state *cs, size_t nbytes)
1147__releases(fiq->waitq.lock)
1148{
1149	int err;
1150	unsigned max_forgets;
1151	unsigned count;
1152	struct fuse_forget_link *head;
1153	struct fuse_batch_forget_in arg = { .count = 0 };
1154	struct fuse_in_header ih = {
1155		.opcode = FUSE_BATCH_FORGET,
1156		.unique = fuse_get_unique(fiq),
1157		.len = sizeof(ih) + sizeof(arg),
1158	};
1159
1160	if (nbytes < ih.len) {
1161		spin_unlock(&fiq->waitq.lock);
1162		return -EINVAL;
1163	}
1164
1165	max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1166	head = dequeue_forget(fiq, max_forgets, &count);
1167	spin_unlock(&fiq->waitq.lock);
1168
1169	arg.count = count;
1170	ih.len += count * sizeof(struct fuse_forget_one);
1171	err = fuse_copy_one(cs, &ih, sizeof(ih));
1172	if (!err)
1173		err = fuse_copy_one(cs, &arg, sizeof(arg));
1174
1175	while (head) {
1176		struct fuse_forget_link *forget = head;
1177
1178		if (!err) {
1179			err = fuse_copy_one(cs, &forget->forget_one,
1180					    sizeof(forget->forget_one));
1181		}
1182		head = forget->next;
1183		kfree(forget);
1184	}
1185
1186	fuse_copy_finish(cs);
1187
1188	if (err)
1189		return err;
1190
1191	return ih.len;
1192}
1193
1194static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1195			    struct fuse_copy_state *cs,
1196			    size_t nbytes)
1197__releases(fiq->waitq.lock)
1198{
1199	if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1200		return fuse_read_single_forget(fiq, cs, nbytes);
1201	else
1202		return fuse_read_batch_forget(fiq, cs, nbytes);
1203}
1204
1205/*
1206 * Read a single request into the userspace filesystem's buffer.  This
1207 * function waits until a request is available, then removes it from
1208 * the pending list and copies request data to userspace buffer.  If
1209 * no reply is needed (FORGET) or request has been aborted or there
1210 * was an error during the copying then it's finished by calling
1211 * request_end().  Otherwise add it to the processing list, and set
1212 * the 'sent' flag.
1213 */
1214static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1215				struct fuse_copy_state *cs, size_t nbytes)
1216{
1217	ssize_t err;
1218	struct fuse_conn *fc = fud->fc;
1219	struct fuse_iqueue *fiq = &fc->iq;
1220	struct fuse_pqueue *fpq = &fud->pq;
1221	struct fuse_req *req;
1222	struct fuse_in *in;
1223	unsigned reqsize;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1224
1225 restart:
1226	spin_lock(&fiq->waitq.lock);
1227	err = -EAGAIN;
1228	if ((file->f_flags & O_NONBLOCK) && fiq->connected &&
1229	    !request_pending(fiq))
1230		goto err_unlock;
1231
1232	err = wait_event_interruptible_exclusive_locked(fiq->waitq,
 
 
1233				!fiq->connected || request_pending(fiq));
1234	if (err)
1235		goto err_unlock;
 
1236
1237	err = -ENODEV;
1238	if (!fiq->connected)
1239		goto err_unlock;
 
1240
1241	if (!list_empty(&fiq->interrupts)) {
1242		req = list_entry(fiq->interrupts.next, struct fuse_req,
1243				 intr_entry);
1244		return fuse_read_interrupt(fiq, cs, nbytes, req);
1245	}
1246
1247	if (forget_pending(fiq)) {
1248		if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1249			return fuse_read_forget(fc, fiq, cs, nbytes);
1250
1251		if (fiq->forget_batch <= -8)
1252			fiq->forget_batch = 16;
1253	}
1254
1255	req = list_entry(fiq->pending.next, struct fuse_req, list);
1256	clear_bit(FR_PENDING, &req->flags);
1257	list_del_init(&req->list);
1258	spin_unlock(&fiq->waitq.lock);
 
 
 
1259
1260	in = &req->in;
1261	reqsize = in->h.len;
1262	/* If request is too large, reply with an error and restart the read */
1263	if (nbytes < reqsize) {
1264		req->out.h.error = -EIO;
1265		/* SETXATTR is special, since it may contain too large data */
1266		if (in->h.opcode == FUSE_SETXATTR)
1267			req->out.h.error = -E2BIG;
1268		request_end(fc, req);
1269		goto restart;
1270	}
1271	spin_lock(&fpq->lock);
 
 
 
 
 
 
 
 
 
1272	list_add(&req->list, &fpq->io);
1273	spin_unlock(&fpq->lock);
1274	cs->req = req;
1275	err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1276	if (!err)
1277		err = fuse_copy_args(cs, in->numargs, in->argpages,
1278				     (struct fuse_arg *) in->args, 0);
1279	fuse_copy_finish(cs);
1280	spin_lock(&fpq->lock);
1281	clear_bit(FR_LOCKED, &req->flags);
1282	if (!fpq->connected) {
1283		err = -ENODEV;
1284		goto out_end;
1285	}
1286	if (err) {
1287		req->out.h.error = -EIO;
1288		goto out_end;
1289	}
1290	if (!test_bit(FR_ISREPLY, &req->flags)) {
1291		err = reqsize;
1292		goto out_end;
1293	}
1294	list_move_tail(&req->list, &fpq->processing);
1295	spin_unlock(&fpq->lock);
 
1296	set_bit(FR_SENT, &req->flags);
 
1297	/* matches barrier in request_wait_answer() */
1298	smp_mb__after_atomic();
1299	if (test_bit(FR_INTERRUPTED, &req->flags))
1300		queue_interrupt(fiq, req);
 
1301
1302	return reqsize;
1303
1304out_end:
1305	if (!test_bit(FR_PRIVATE, &req->flags))
1306		list_del_init(&req->list);
1307	spin_unlock(&fpq->lock);
1308	request_end(fc, req);
1309	return err;
1310
1311 err_unlock:
1312	spin_unlock(&fiq->waitq.lock);
1313	return err;
1314}
1315
1316static int fuse_dev_open(struct inode *inode, struct file *file)
1317{
1318	/*
1319	 * The fuse device's file's private_data is used to hold
1320	 * the fuse_conn(ection) when it is mounted, and is used to
1321	 * keep track of whether the file has been mounted already.
1322	 */
1323	file->private_data = NULL;
1324	return 0;
1325}
1326
1327static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1328{
1329	struct fuse_copy_state cs;
1330	struct file *file = iocb->ki_filp;
1331	struct fuse_dev *fud = fuse_get_dev(file);
1332
1333	if (!fud)
1334		return -EPERM;
1335
1336	if (!iter_is_iovec(to))
1337		return -EINVAL;
1338
1339	fuse_copy_init(&cs, 1, to);
1340
1341	return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1342}
1343
1344static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1345				    struct pipe_inode_info *pipe,
1346				    size_t len, unsigned int flags)
1347{
1348	int total, ret;
1349	int page_nr = 0;
1350	struct pipe_buffer *bufs;
1351	struct fuse_copy_state cs;
1352	struct fuse_dev *fud = fuse_get_dev(in);
1353
1354	if (!fud)
1355		return -EPERM;
1356
1357	bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
 
1358	if (!bufs)
1359		return -ENOMEM;
1360
1361	fuse_copy_init(&cs, 1, NULL);
1362	cs.pipebufs = bufs;
1363	cs.pipe = pipe;
1364	ret = fuse_dev_do_read(fud, in, &cs, len);
1365	if (ret < 0)
1366		goto out;
1367
1368	if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1369		ret = -EIO;
1370		goto out;
1371	}
1372
1373	for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1374		/*
1375		 * Need to be careful about this.  Having buf->ops in module
1376		 * code can Oops if the buffer persists after module unload.
1377		 */
1378		bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1379		bufs[page_nr].flags = 0;
1380		ret = add_to_pipe(pipe, &bufs[page_nr++]);
1381		if (unlikely(ret < 0))
1382			break;
1383	}
1384	if (total)
1385		ret = total;
1386out:
1387	for (; page_nr < cs.nr_segs; page_nr++)
1388		put_page(bufs[page_nr].page);
1389
1390	kfree(bufs);
1391	return ret;
1392}
1393
1394static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1395			    struct fuse_copy_state *cs)
1396{
1397	struct fuse_notify_poll_wakeup_out outarg;
1398	int err = -EINVAL;
1399
1400	if (size != sizeof(outarg))
1401		goto err;
1402
1403	err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1404	if (err)
1405		goto err;
1406
1407	fuse_copy_finish(cs);
1408	return fuse_notify_poll_wakeup(fc, &outarg);
1409
1410err:
1411	fuse_copy_finish(cs);
1412	return err;
1413}
1414
1415static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1416				   struct fuse_copy_state *cs)
1417{
1418	struct fuse_notify_inval_inode_out outarg;
1419	int err = -EINVAL;
1420
1421	if (size != sizeof(outarg))
1422		goto err;
1423
1424	err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1425	if (err)
1426		goto err;
1427	fuse_copy_finish(cs);
1428
1429	down_read(&fc->killsb);
1430	err = -ENOENT;
1431	if (fc->sb) {
1432		err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1433					       outarg.off, outarg.len);
1434	}
1435	up_read(&fc->killsb);
1436	return err;
1437
1438err:
1439	fuse_copy_finish(cs);
1440	return err;
1441}
1442
1443static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1444				   struct fuse_copy_state *cs)
1445{
1446	struct fuse_notify_inval_entry_out outarg;
1447	int err = -ENOMEM;
1448	char *buf;
1449	struct qstr name;
1450
1451	buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1452	if (!buf)
1453		goto err;
1454
1455	err = -EINVAL;
1456	if (size < sizeof(outarg))
1457		goto err;
1458
1459	err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1460	if (err)
1461		goto err;
1462
1463	err = -ENAMETOOLONG;
1464	if (outarg.namelen > FUSE_NAME_MAX)
1465		goto err;
1466
1467	err = -EINVAL;
1468	if (size != sizeof(outarg) + outarg.namelen + 1)
1469		goto err;
1470
1471	name.name = buf;
1472	name.len = outarg.namelen;
1473	err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1474	if (err)
1475		goto err;
1476	fuse_copy_finish(cs);
1477	buf[outarg.namelen] = 0;
1478
1479	down_read(&fc->killsb);
1480	err = -ENOENT;
1481	if (fc->sb)
1482		err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1483	up_read(&fc->killsb);
1484	kfree(buf);
1485	return err;
1486
1487err:
1488	kfree(buf);
1489	fuse_copy_finish(cs);
1490	return err;
1491}
1492
1493static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1494			      struct fuse_copy_state *cs)
1495{
1496	struct fuse_notify_delete_out outarg;
1497	int err = -ENOMEM;
1498	char *buf;
1499	struct qstr name;
1500
1501	buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1502	if (!buf)
1503		goto err;
1504
1505	err = -EINVAL;
1506	if (size < sizeof(outarg))
1507		goto err;
1508
1509	err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1510	if (err)
1511		goto err;
1512
1513	err = -ENAMETOOLONG;
1514	if (outarg.namelen > FUSE_NAME_MAX)
1515		goto err;
1516
1517	err = -EINVAL;
1518	if (size != sizeof(outarg) + outarg.namelen + 1)
1519		goto err;
1520
1521	name.name = buf;
1522	name.len = outarg.namelen;
1523	err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1524	if (err)
1525		goto err;
1526	fuse_copy_finish(cs);
1527	buf[outarg.namelen] = 0;
1528
1529	down_read(&fc->killsb);
1530	err = -ENOENT;
1531	if (fc->sb)
1532		err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1533					       outarg.child, &name);
1534	up_read(&fc->killsb);
1535	kfree(buf);
1536	return err;
1537
1538err:
1539	kfree(buf);
1540	fuse_copy_finish(cs);
1541	return err;
1542}
1543
1544static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1545			     struct fuse_copy_state *cs)
1546{
1547	struct fuse_notify_store_out outarg;
1548	struct inode *inode;
1549	struct address_space *mapping;
1550	u64 nodeid;
1551	int err;
1552	pgoff_t index;
1553	unsigned int offset;
1554	unsigned int num;
1555	loff_t file_size;
1556	loff_t end;
1557
1558	err = -EINVAL;
1559	if (size < sizeof(outarg))
1560		goto out_finish;
1561
1562	err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1563	if (err)
1564		goto out_finish;
1565
1566	err = -EINVAL;
1567	if (size - sizeof(outarg) != outarg.size)
1568		goto out_finish;
1569
1570	nodeid = outarg.nodeid;
1571
1572	down_read(&fc->killsb);
1573
1574	err = -ENOENT;
1575	if (!fc->sb)
1576		goto out_up_killsb;
1577
1578	inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1579	if (!inode)
1580		goto out_up_killsb;
1581
1582	mapping = inode->i_mapping;
1583	index = outarg.offset >> PAGE_SHIFT;
1584	offset = outarg.offset & ~PAGE_MASK;
1585	file_size = i_size_read(inode);
1586	end = outarg.offset + outarg.size;
1587	if (end > file_size) {
1588		file_size = end;
1589		fuse_write_update_size(inode, file_size);
1590	}
1591
1592	num = outarg.size;
1593	while (num) {
1594		struct page *page;
1595		unsigned int this_num;
1596
1597		err = -ENOMEM;
1598		page = find_or_create_page(mapping, index,
1599					   mapping_gfp_mask(mapping));
1600		if (!page)
1601			goto out_iput;
1602
1603		this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1604		err = fuse_copy_page(cs, &page, offset, this_num, 0);
1605		if (!err && offset == 0 &&
1606		    (this_num == PAGE_SIZE || file_size == end))
1607			SetPageUptodate(page);
1608		unlock_page(page);
1609		put_page(page);
1610
1611		if (err)
1612			goto out_iput;
1613
1614		num -= this_num;
1615		offset = 0;
1616		index++;
1617	}
1618
1619	err = 0;
1620
1621out_iput:
1622	iput(inode);
1623out_up_killsb:
1624	up_read(&fc->killsb);
1625out_finish:
1626	fuse_copy_finish(cs);
1627	return err;
1628}
1629
1630static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
 
 
 
 
 
 
1631{
1632	release_pages(req->pages, req->num_pages, false);
 
 
 
 
1633}
1634
1635static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1636			 struct fuse_notify_retrieve_out *outarg)
1637{
1638	int err;
1639	struct address_space *mapping = inode->i_mapping;
1640	struct fuse_req *req;
1641	pgoff_t index;
1642	loff_t file_size;
1643	unsigned int num;
1644	unsigned int offset;
1645	size_t total_len = 0;
1646	int num_pages;
 
 
 
 
 
1647
1648	offset = outarg->offset & ~PAGE_MASK;
1649	file_size = i_size_read(inode);
1650
1651	num = outarg->size;
1652	if (outarg->offset > file_size)
1653		num = 0;
1654	else if (outarg->offset + num > file_size)
1655		num = file_size - outarg->offset;
1656
1657	num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1658	num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ);
1659
1660	req = fuse_get_req(fc, num_pages);
1661	if (IS_ERR(req))
1662		return PTR_ERR(req);
1663
1664	req->in.h.opcode = FUSE_NOTIFY_REPLY;
1665	req->in.h.nodeid = outarg->nodeid;
1666	req->in.numargs = 2;
1667	req->in.argpages = 1;
1668	req->page_descs[0].offset = offset;
1669	req->end = fuse_retrieve_end;
 
 
 
 
 
 
 
 
1670
1671	index = outarg->offset >> PAGE_SHIFT;
1672
1673	while (num && req->num_pages < num_pages) {
1674		struct page *page;
1675		unsigned int this_num;
1676
1677		page = find_get_page(mapping, index);
1678		if (!page)
1679			break;
1680
1681		this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1682		req->pages[req->num_pages] = page;
1683		req->page_descs[req->num_pages].length = this_num;
1684		req->num_pages++;
 
1685
1686		offset = 0;
1687		num -= this_num;
1688		total_len += this_num;
1689		index++;
1690	}
1691	req->misc.retrieve_in.offset = outarg->offset;
1692	req->misc.retrieve_in.size = total_len;
1693	req->in.args[0].size = sizeof(req->misc.retrieve_in);
1694	req->in.args[0].value = &req->misc.retrieve_in;
1695	req->in.args[1].size = total_len;
1696
1697	err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1698	if (err)
1699		fuse_retrieve_end(fc, req);
1700
1701	return err;
1702}
1703
1704static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1705				struct fuse_copy_state *cs)
1706{
1707	struct fuse_notify_retrieve_out outarg;
 
1708	struct inode *inode;
 
1709	int err;
1710
1711	err = -EINVAL;
1712	if (size != sizeof(outarg))
1713		goto copy_finish;
1714
1715	err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1716	if (err)
1717		goto copy_finish;
1718
1719	fuse_copy_finish(cs);
1720
1721	down_read(&fc->killsb);
1722	err = -ENOENT;
1723	if (fc->sb) {
1724		u64 nodeid = outarg.nodeid;
1725
1726		inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1727		if (inode) {
1728			err = fuse_retrieve(fc, inode, &outarg);
1729			iput(inode);
1730		}
1731	}
1732	up_read(&fc->killsb);
1733
1734	return err;
1735
1736copy_finish:
1737	fuse_copy_finish(cs);
1738	return err;
1739}
1740
1741static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1742		       unsigned int size, struct fuse_copy_state *cs)
1743{
1744	/* Don't try to move pages (yet) */
1745	cs->move_pages = 0;
1746
1747	switch (code) {
1748	case FUSE_NOTIFY_POLL:
1749		return fuse_notify_poll(fc, size, cs);
1750
1751	case FUSE_NOTIFY_INVAL_INODE:
1752		return fuse_notify_inval_inode(fc, size, cs);
1753
1754	case FUSE_NOTIFY_INVAL_ENTRY:
1755		return fuse_notify_inval_entry(fc, size, cs);
1756
1757	case FUSE_NOTIFY_STORE:
1758		return fuse_notify_store(fc, size, cs);
1759
1760	case FUSE_NOTIFY_RETRIEVE:
1761		return fuse_notify_retrieve(fc, size, cs);
1762
1763	case FUSE_NOTIFY_DELETE:
1764		return fuse_notify_delete(fc, size, cs);
1765
1766	default:
1767		fuse_copy_finish(cs);
1768		return -EINVAL;
1769	}
1770}
1771
1772/* Look up request on processing list by unique ID */
1773static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1774{
 
1775	struct fuse_req *req;
1776
1777	list_for_each_entry(req, &fpq->processing, list) {
1778		if (req->in.h.unique == unique || req->intr_unique == unique)
1779			return req;
1780	}
1781	return NULL;
1782}
1783
1784static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1785			 unsigned nbytes)
1786{
1787	unsigned reqsize = sizeof(struct fuse_out_header);
1788
1789	if (out->h.error)
1790		return nbytes != reqsize ? -EINVAL : 0;
1791
1792	reqsize += len_args(out->numargs, out->args);
1793
1794	if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1795		return -EINVAL;
1796	else if (reqsize > nbytes) {
1797		struct fuse_arg *lastarg = &out->args[out->numargs-1];
1798		unsigned diffsize = reqsize - nbytes;
 
1799		if (diffsize > lastarg->size)
1800			return -EINVAL;
1801		lastarg->size -= diffsize;
1802	}
1803	return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1804			      out->page_zeroing);
1805}
1806
1807/*
1808 * Write a single reply to a request.  First the header is copied from
1809 * the write buffer.  The request is then searched on the processing
1810 * list by the unique ID found in the header.  If found, then remove
1811 * it from the list and copy the rest of the buffer to the request.
1812 * The request is finished by calling request_end()
1813 */
1814static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1815				 struct fuse_copy_state *cs, size_t nbytes)
1816{
1817	int err;
1818	struct fuse_conn *fc = fud->fc;
1819	struct fuse_pqueue *fpq = &fud->pq;
1820	struct fuse_req *req;
1821	struct fuse_out_header oh;
1822
 
1823	if (nbytes < sizeof(struct fuse_out_header))
1824		return -EINVAL;
1825
1826	err = fuse_copy_one(cs, &oh, sizeof(oh));
1827	if (err)
1828		goto err_finish;
1829
1830	err = -EINVAL;
1831	if (oh.len != nbytes)
1832		goto err_finish;
1833
1834	/*
1835	 * Zero oh.unique indicates unsolicited notification message
1836	 * and error contains notification code.
1837	 */
1838	if (!oh.unique) {
1839		err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1840		return err ? err : nbytes;
1841	}
1842
1843	err = -EINVAL;
1844	if (oh.error <= -1000 || oh.error > 0)
1845		goto err_finish;
1846
1847	spin_lock(&fpq->lock);
1848	err = -ENOENT;
1849	if (!fpq->connected)
1850		goto err_unlock_pq;
1851
1852	req = request_find(fpq, oh.unique);
1853	if (!req)
1854		goto err_unlock_pq;
 
 
1855
1856	/* Is it an interrupt reply? */
1857	if (req->intr_unique == oh.unique) {
 
1858		spin_unlock(&fpq->lock);
1859
1860		err = -EINVAL;
1861		if (nbytes != sizeof(struct fuse_out_header))
1862			goto err_finish;
1863
1864		if (oh.error == -ENOSYS)
1865			fc->no_interrupt = 1;
1866		else if (oh.error == -EAGAIN)
1867			queue_interrupt(&fc->iq, req);
1868
1869		fuse_copy_finish(cs);
1870		return nbytes;
 
1871	}
1872
1873	clear_bit(FR_SENT, &req->flags);
1874	list_move(&req->list, &fpq->io);
1875	req->out.h = oh;
1876	set_bit(FR_LOCKED, &req->flags);
1877	spin_unlock(&fpq->lock);
1878	cs->req = req;
1879	if (!req->out.page_replace)
1880		cs->move_pages = 0;
1881
1882	err = copy_out_args(cs, &req->out, nbytes);
 
 
 
1883	fuse_copy_finish(cs);
1884
1885	spin_lock(&fpq->lock);
1886	clear_bit(FR_LOCKED, &req->flags);
1887	if (!fpq->connected)
1888		err = -ENOENT;
1889	else if (err)
1890		req->out.h.error = -EIO;
1891	if (!test_bit(FR_PRIVATE, &req->flags))
1892		list_del_init(&req->list);
1893	spin_unlock(&fpq->lock);
1894
1895	request_end(fc, req);
1896
1897	return err ? err : nbytes;
1898
1899 err_unlock_pq:
1900	spin_unlock(&fpq->lock);
1901 err_finish:
1902	fuse_copy_finish(cs);
1903	return err;
1904}
1905
1906static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1907{
1908	struct fuse_copy_state cs;
1909	struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1910
1911	if (!fud)
1912		return -EPERM;
1913
1914	if (!iter_is_iovec(from))
1915		return -EINVAL;
1916
1917	fuse_copy_init(&cs, 0, from);
1918
1919	return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1920}
1921
1922static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1923				     struct file *out, loff_t *ppos,
1924				     size_t len, unsigned int flags)
1925{
 
1926	unsigned nbuf;
1927	unsigned idx;
1928	struct pipe_buffer *bufs;
1929	struct fuse_copy_state cs;
1930	struct fuse_dev *fud;
1931	size_t rem;
1932	ssize_t ret;
1933
1934	fud = fuse_get_dev(out);
1935	if (!fud)
1936		return -EPERM;
1937
1938	bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1939	if (!bufs)
 
 
 
 
 
 
 
 
1940		return -ENOMEM;
 
1941
1942	pipe_lock(pipe);
1943	nbuf = 0;
1944	rem = 0;
1945	for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1946		rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1947
1948	ret = -EINVAL;
1949	if (rem < len) {
1950		pipe_unlock(pipe);
1951		goto out;
1952	}
1953
1954	rem = len;
1955	while (rem) {
1956		struct pipe_buffer *ibuf;
1957		struct pipe_buffer *obuf;
1958
1959		BUG_ON(nbuf >= pipe->buffers);
1960		BUG_ON(!pipe->nrbufs);
1961		ibuf = &pipe->bufs[pipe->curbuf];
 
1962		obuf = &bufs[nbuf];
1963
1964		if (rem >= ibuf->len) {
1965			*obuf = *ibuf;
1966			ibuf->ops = NULL;
1967			pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1968			pipe->nrbufs--;
1969		} else {
1970			pipe_buf_get(pipe, ibuf);
 
 
1971			*obuf = *ibuf;
1972			obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1973			obuf->len = rem;
1974			ibuf->offset += obuf->len;
1975			ibuf->len -= obuf->len;
1976		}
1977		nbuf++;
1978		rem -= obuf->len;
1979	}
1980	pipe_unlock(pipe);
1981
1982	fuse_copy_init(&cs, 0, NULL);
1983	cs.pipebufs = bufs;
1984	cs.nr_segs = nbuf;
1985	cs.pipe = pipe;
1986
1987	if (flags & SPLICE_F_MOVE)
1988		cs.move_pages = 1;
1989
1990	ret = fuse_dev_do_write(fud, &cs, len);
1991
1992	for (idx = 0; idx < nbuf; idx++)
1993		pipe_buf_release(pipe, &bufs[idx]);
 
 
1994
1995out:
1996	kfree(bufs);
 
 
 
 
1997	return ret;
1998}
1999
2000static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
2001{
2002	unsigned mask = POLLOUT | POLLWRNORM;
2003	struct fuse_iqueue *fiq;
2004	struct fuse_dev *fud = fuse_get_dev(file);
2005
2006	if (!fud)
2007		return POLLERR;
2008
2009	fiq = &fud->fc->iq;
2010	poll_wait(file, &fiq->waitq, wait);
2011
2012	spin_lock(&fiq->waitq.lock);
2013	if (!fiq->connected)
2014		mask = POLLERR;
2015	else if (request_pending(fiq))
2016		mask |= POLLIN | POLLRDNORM;
2017	spin_unlock(&fiq->waitq.lock);
2018
2019	return mask;
2020}
2021
2022/*
2023 * Abort all requests on the given list (pending or processing)
2024 *
2025 * This function releases and reacquires fc->lock
2026 */
2027static void end_requests(struct fuse_conn *fc, struct list_head *head)
2028{
2029	while (!list_empty(head)) {
2030		struct fuse_req *req;
2031		req = list_entry(head->next, struct fuse_req, list);
2032		req->out.h.error = -ECONNABORTED;
2033		clear_bit(FR_SENT, &req->flags);
2034		list_del_init(&req->list);
2035		request_end(fc, req);
2036	}
2037}
2038
2039static void end_polls(struct fuse_conn *fc)
2040{
2041	struct rb_node *p;
2042
2043	p = rb_first(&fc->polled_files);
2044
2045	while (p) {
2046		struct fuse_file *ff;
2047		ff = rb_entry(p, struct fuse_file, polled_node);
2048		wake_up_interruptible_all(&ff->poll_wait);
2049
2050		p = rb_next(p);
2051	}
2052}
2053
2054/*
2055 * Abort all requests.
2056 *
2057 * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2058 * filesystem.
2059 *
2060 * The same effect is usually achievable through killing the filesystem daemon
2061 * and all users of the filesystem.  The exception is the combination of an
2062 * asynchronous request and the tricky deadlock (see
2063 * Documentation/filesystems/fuse.txt).
2064 *
2065 * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2066 * requests, they should be finished off immediately.  Locked requests will be
2067 * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2068 * requests.  It is possible that some request will finish before we can.  This
2069 * is OK, the request will in that case be removed from the list before we touch
2070 * it.
2071 */
2072void fuse_abort_conn(struct fuse_conn *fc)
2073{
2074	struct fuse_iqueue *fiq = &fc->iq;
2075
2076	spin_lock(&fc->lock);
2077	if (fc->connected) {
2078		struct fuse_dev *fud;
2079		struct fuse_req *req, *next;
2080		LIST_HEAD(to_end1);
2081		LIST_HEAD(to_end2);
2082
 
 
2083		fc->connected = 0;
2084		fc->blocked = 0;
 
2085		fuse_set_initialized(fc);
2086		list_for_each_entry(fud, &fc->devices, entry) {
2087			struct fuse_pqueue *fpq = &fud->pq;
2088
2089			spin_lock(&fpq->lock);
2090			fpq->connected = 0;
2091			list_for_each_entry_safe(req, next, &fpq->io, list) {
2092				req->out.h.error = -ECONNABORTED;
2093				spin_lock(&req->waitq.lock);
2094				set_bit(FR_ABORTED, &req->flags);
2095				if (!test_bit(FR_LOCKED, &req->flags)) {
2096					set_bit(FR_PRIVATE, &req->flags);
2097					list_move(&req->list, &to_end1);
 
2098				}
2099				spin_unlock(&req->waitq.lock);
2100			}
2101			list_splice_init(&fpq->processing, &to_end2);
 
 
2102			spin_unlock(&fpq->lock);
2103		}
 
 
2104		fc->max_background = UINT_MAX;
2105		flush_bg_queue(fc);
 
2106
2107		spin_lock(&fiq->waitq.lock);
2108		fiq->connected = 0;
2109		list_splice_init(&fiq->pending, &to_end2);
2110		list_for_each_entry(req, &to_end2, list)
2111			clear_bit(FR_PENDING, &req->flags);
 
2112		while (forget_pending(fiq))
2113			kfree(dequeue_forget(fiq, 1, NULL));
2114		wake_up_all_locked(&fiq->waitq);
2115		spin_unlock(&fiq->waitq.lock);
2116		kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2117		end_polls(fc);
2118		wake_up_all(&fc->blocked_waitq);
2119		spin_unlock(&fc->lock);
2120
2121		while (!list_empty(&to_end1)) {
2122			req = list_first_entry(&to_end1, struct fuse_req, list);
2123			__fuse_get_request(req);
2124			list_del_init(&req->list);
2125			request_end(fc, req);
2126		}
2127		end_requests(fc, &to_end2);
2128	} else {
2129		spin_unlock(&fc->lock);
2130	}
2131}
2132EXPORT_SYMBOL_GPL(fuse_abort_conn);
2133
 
 
 
 
 
 
 
2134int fuse_dev_release(struct inode *inode, struct file *file)
2135{
2136	struct fuse_dev *fud = fuse_get_dev(file);
2137
2138	if (fud) {
2139		struct fuse_conn *fc = fud->fc;
2140		struct fuse_pqueue *fpq = &fud->pq;
 
 
2141
 
2142		WARN_ON(!list_empty(&fpq->io));
2143		end_requests(fc, &fpq->processing);
 
 
 
 
 
2144		/* Are we the last open device? */
2145		if (atomic_dec_and_test(&fc->dev_count)) {
2146			WARN_ON(fc->iq.fasync != NULL);
2147			fuse_abort_conn(fc);
2148		}
2149		fuse_dev_free(fud);
2150	}
2151	return 0;
2152}
2153EXPORT_SYMBOL_GPL(fuse_dev_release);
2154
2155static int fuse_dev_fasync(int fd, struct file *file, int on)
2156{
2157	struct fuse_dev *fud = fuse_get_dev(file);
2158
2159	if (!fud)
2160		return -EPERM;
2161
2162	/* No locking - fasync_helper does its own locking */
2163	return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2164}
2165
2166static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2167{
2168	struct fuse_dev *fud;
2169
2170	if (new->private_data)
2171		return -EINVAL;
2172
2173	fud = fuse_dev_alloc(fc);
2174	if (!fud)
2175		return -ENOMEM;
2176
2177	new->private_data = fud;
2178	atomic_inc(&fc->dev_count);
2179
2180	return 0;
2181}
2182
2183static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2184			   unsigned long arg)
2185{
2186	int err = -ENOTTY;
2187
2188	if (cmd == FUSE_DEV_IOC_CLONE) {
2189		int oldfd;
2190
2191		err = -EFAULT;
2192		if (!get_user(oldfd, (__u32 __user *) arg)) {
 
2193			struct file *old = fget(oldfd);
2194
2195			err = -EINVAL;
2196			if (old) {
2197				struct fuse_dev *fud = NULL;
2198
2199				/*
2200				 * Check against file->f_op because CUSE
2201				 * uses the same ioctl handler.
2202				 */
2203				if (old->f_op == file->f_op &&
2204				    old->f_cred->user_ns == file->f_cred->user_ns)
2205					fud = fuse_get_dev(old);
2206
2207				if (fud) {
2208					mutex_lock(&fuse_mutex);
2209					err = fuse_device_clone(fud->fc, file);
2210					mutex_unlock(&fuse_mutex);
2211				}
2212				fput(old);
2213			}
2214		}
 
 
 
 
2215	}
2216	return err;
2217}
2218
2219const struct file_operations fuse_dev_operations = {
2220	.owner		= THIS_MODULE,
2221	.open		= fuse_dev_open,
2222	.llseek		= no_llseek,
2223	.read_iter	= fuse_dev_read,
2224	.splice_read	= fuse_dev_splice_read,
2225	.write_iter	= fuse_dev_write,
2226	.splice_write	= fuse_dev_splice_write,
2227	.poll		= fuse_dev_poll,
2228	.release	= fuse_dev_release,
2229	.fasync		= fuse_dev_fasync,
2230	.unlocked_ioctl = fuse_dev_ioctl,
2231	.compat_ioctl   = fuse_dev_ioctl,
2232};
2233EXPORT_SYMBOL_GPL(fuse_dev_operations);
2234
2235static struct miscdevice fuse_miscdevice = {
2236	.minor = FUSE_MINOR,
2237	.name  = "fuse",
2238	.fops = &fuse_dev_operations,
2239};
2240
2241int __init fuse_dev_init(void)
2242{
2243	int err = -ENOMEM;
2244	fuse_req_cachep = kmem_cache_create("fuse_request",
2245					    sizeof(struct fuse_req),
2246					    0, 0, NULL);
2247	if (!fuse_req_cachep)
2248		goto out;
2249
2250	err = misc_register(&fuse_miscdevice);
2251	if (err)
2252		goto out_cache_clean;
2253
2254	return 0;
2255
2256 out_cache_clean:
2257	kmem_cache_destroy(fuse_req_cachep);
2258 out:
2259	return err;
2260}
2261
2262void fuse_dev_cleanup(void)
2263{
2264	misc_deregister(&fuse_miscdevice);
2265	kmem_cache_destroy(fuse_req_cachep);
2266}