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/pagemap.h>
  12#include <linux/slab.h>
  13#include <linux/kernel.h>
  14#include <linux/sched.h>
  15#include <linux/module.h>
  16#include <linux/compat.h>
  17#include <linux/swap.h>
  18
  19static const struct file_operations fuse_direct_io_file_operations;
  20
  21static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
  22			  int opcode, struct fuse_open_out *outargp)
  23{
  24	struct fuse_open_in inarg;
  25	struct fuse_req *req;
  26	int err;
  27
  28	req = fuse_get_req(fc);
  29	if (IS_ERR(req))
  30		return PTR_ERR(req);
  31
  32	memset(&inarg, 0, sizeof(inarg));
  33	inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
  34	if (!fc->atomic_o_trunc)
  35		inarg.flags &= ~O_TRUNC;
  36	req->in.h.opcode = opcode;
  37	req->in.h.nodeid = nodeid;
  38	req->in.numargs = 1;
  39	req->in.args[0].size = sizeof(inarg);
  40	req->in.args[0].value = &inarg;
  41	req->out.numargs = 1;
  42	req->out.args[0].size = sizeof(*outargp);
  43	req->out.args[0].value = outargp;
  44	fuse_request_send(fc, req);
  45	err = req->out.h.error;
  46	fuse_put_request(fc, req);
  47
  48	return err;
  49}
  50
  51struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
  52{
  53	struct fuse_file *ff;
  54
  55	ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
  56	if (unlikely(!ff))
  57		return NULL;
  58
  59	ff->fc = fc;
  60	ff->reserved_req = fuse_request_alloc();
  61	if (unlikely(!ff->reserved_req)) {
  62		kfree(ff);
  63		return NULL;
  64	}
  65
  66	INIT_LIST_HEAD(&ff->write_entry);
  67	atomic_set(&ff->count, 0);
  68	RB_CLEAR_NODE(&ff->polled_node);
  69	init_waitqueue_head(&ff->poll_wait);
  70
  71	spin_lock(&fc->lock);
  72	ff->kh = ++fc->khctr;
  73	spin_unlock(&fc->lock);
  74
  75	return ff;
  76}
  77
  78void fuse_file_free(struct fuse_file *ff)
  79{
  80	fuse_request_free(ff->reserved_req);
  81	kfree(ff);
  82}
  83
  84struct fuse_file *fuse_file_get(struct fuse_file *ff)
  85{
  86	atomic_inc(&ff->count);
  87	return ff;
  88}
  89
  90static void fuse_release_async(struct work_struct *work)
  91{
  92	struct fuse_req *req;
  93	struct fuse_conn *fc;
  94	struct path path;
  95
  96	req = container_of(work, struct fuse_req, misc.release.work);
  97	path = req->misc.release.path;
  98	fc = get_fuse_conn(path.dentry->d_inode);
  99
 100	fuse_put_request(fc, req);
 101	path_put(&path);
 102}
 103
 104static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
 105{
 106	if (fc->destroy_req) {
 107		/*
 108		 * If this is a fuseblk mount, then it's possible that
 109		 * releasing the path will result in releasing the
 110		 * super block and sending the DESTROY request.  If
 111		 * the server is single threaded, this would hang.
 112		 * For this reason do the path_put() in a separate
 113		 * thread.
 114		 */
 115		atomic_inc(&req->count);
 116		INIT_WORK(&req->misc.release.work, fuse_release_async);
 117		schedule_work(&req->misc.release.work);
 118	} else {
 119		path_put(&req->misc.release.path);
 120	}
 121}
 122
 123static void fuse_file_put(struct fuse_file *ff, bool sync)
 124{
 125	if (atomic_dec_and_test(&ff->count)) {
 126		struct fuse_req *req = ff->reserved_req;
 127
 128		if (sync) {
 129			fuse_request_send(ff->fc, req);
 130			path_put(&req->misc.release.path);
 131			fuse_put_request(ff->fc, req);
 132		} else {
 133			req->end = fuse_release_end;
 134			fuse_request_send_background(ff->fc, req);
 135		}
 136		kfree(ff);
 137	}
 138}
 139
 140int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 141		 bool isdir)
 142{
 143	struct fuse_open_out outarg;
 144	struct fuse_file *ff;
 145	int err;
 146	int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
 147
 148	ff = fuse_file_alloc(fc);
 149	if (!ff)
 150		return -ENOMEM;
 151
 152	err = fuse_send_open(fc, nodeid, file, opcode, &outarg);
 153	if (err) {
 154		fuse_file_free(ff);
 155		return err;
 156	}
 157
 158	if (isdir)
 159		outarg.open_flags &= ~FOPEN_DIRECT_IO;
 160
 161	ff->fh = outarg.fh;
 162	ff->nodeid = nodeid;
 163	ff->open_flags = outarg.open_flags;
 164	file->private_data = fuse_file_get(ff);
 165
 166	return 0;
 167}
 168EXPORT_SYMBOL_GPL(fuse_do_open);
 169
 170void fuse_finish_open(struct inode *inode, struct file *file)
 171{
 172	struct fuse_file *ff = file->private_data;
 173	struct fuse_conn *fc = get_fuse_conn(inode);
 174
 175	if (ff->open_flags & FOPEN_DIRECT_IO)
 176		file->f_op = &fuse_direct_io_file_operations;
 177	if (!(ff->open_flags & FOPEN_KEEP_CACHE))
 178		invalidate_inode_pages2(inode->i_mapping);
 179	if (ff->open_flags & FOPEN_NONSEEKABLE)
 180		nonseekable_open(inode, file);
 181	if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) {
 182		struct fuse_inode *fi = get_fuse_inode(inode);
 183
 184		spin_lock(&fc->lock);
 185		fi->attr_version = ++fc->attr_version;
 186		i_size_write(inode, 0);
 187		spin_unlock(&fc->lock);
 188		fuse_invalidate_attr(inode);
 189	}
 190}
 191
 192int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
 193{
 194	struct fuse_conn *fc = get_fuse_conn(inode);
 195	int err;
 196
 
 
 
 
 197	err = generic_file_open(inode, file);
 198	if (err)
 199		return err;
 200
 201	err = fuse_do_open(fc, get_node_id(inode), file, isdir);
 202	if (err)
 203		return err;
 204
 205	fuse_finish_open(inode, file);
 206
 207	return 0;
 208}
 209
 210static void fuse_prepare_release(struct fuse_file *ff, int flags, int opcode)
 211{
 212	struct fuse_conn *fc = ff->fc;
 213	struct fuse_req *req = ff->reserved_req;
 214	struct fuse_release_in *inarg = &req->misc.release.in;
 215
 216	spin_lock(&fc->lock);
 217	list_del(&ff->write_entry);
 218	if (!RB_EMPTY_NODE(&ff->polled_node))
 219		rb_erase(&ff->polled_node, &fc->polled_files);
 220	spin_unlock(&fc->lock);
 221
 222	wake_up_interruptible_all(&ff->poll_wait);
 223
 224	inarg->fh = ff->fh;
 225	inarg->flags = flags;
 226	req->in.h.opcode = opcode;
 227	req->in.h.nodeid = ff->nodeid;
 228	req->in.numargs = 1;
 229	req->in.args[0].size = sizeof(struct fuse_release_in);
 230	req->in.args[0].value = inarg;
 231}
 232
 233void fuse_release_common(struct file *file, int opcode)
 234{
 235	struct fuse_file *ff;
 236	struct fuse_req *req;
 237
 238	ff = file->private_data;
 239	if (unlikely(!ff))
 240		return;
 241
 242	req = ff->reserved_req;
 243	fuse_prepare_release(ff, file->f_flags, opcode);
 244
 245	if (ff->flock) {
 246		struct fuse_release_in *inarg = &req->misc.release.in;
 247		inarg->release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
 248		inarg->lock_owner = fuse_lock_owner_id(ff->fc,
 249						       (fl_owner_t) file);
 250	}
 251	/* Hold vfsmount and dentry until release is finished */
 252	path_get(&file->f_path);
 253	req->misc.release.path = file->f_path;
 254
 255	/*
 256	 * Normally this will send the RELEASE request, however if
 257	 * some asynchronous READ or WRITE requests are outstanding,
 258	 * the sending will be delayed.
 259	 *
 260	 * Make the release synchronous if this is a fuseblk mount,
 261	 * synchronous RELEASE is allowed (and desirable) in this case
 262	 * because the server can be trusted not to screw up.
 263	 */
 264	fuse_file_put(ff, ff->fc->destroy_req != NULL);
 265}
 266
 267static int fuse_open(struct inode *inode, struct file *file)
 268{
 269	return fuse_open_common(inode, file, false);
 270}
 271
 272static int fuse_release(struct inode *inode, struct file *file)
 273{
 274	fuse_release_common(file, FUSE_RELEASE);
 275
 276	/* return value is ignored by VFS */
 277	return 0;
 278}
 279
 280void fuse_sync_release(struct fuse_file *ff, int flags)
 281{
 282	WARN_ON(atomic_read(&ff->count) > 1);
 283	fuse_prepare_release(ff, flags, FUSE_RELEASE);
 284	ff->reserved_req->force = 1;
 285	fuse_request_send(ff->fc, ff->reserved_req);
 286	fuse_put_request(ff->fc, ff->reserved_req);
 287	kfree(ff);
 288}
 289EXPORT_SYMBOL_GPL(fuse_sync_release);
 290
 291/*
 292 * Scramble the ID space with XTEA, so that the value of the files_struct
 293 * pointer is not exposed to userspace.
 294 */
 295u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
 296{
 297	u32 *k = fc->scramble_key;
 298	u64 v = (unsigned long) id;
 299	u32 v0 = v;
 300	u32 v1 = v >> 32;
 301	u32 sum = 0;
 302	int i;
 303
 304	for (i = 0; i < 32; i++) {
 305		v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
 306		sum += 0x9E3779B9;
 307		v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
 308	}
 309
 310	return (u64) v0 + ((u64) v1 << 32);
 311}
 312
 313/*
 314 * Check if page is under writeback
 315 *
 316 * This is currently done by walking the list of writepage requests
 317 * for the inode, which can be pretty inefficient.
 318 */
 319static bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
 320{
 321	struct fuse_conn *fc = get_fuse_conn(inode);
 322	struct fuse_inode *fi = get_fuse_inode(inode);
 323	struct fuse_req *req;
 324	bool found = false;
 325
 326	spin_lock(&fc->lock);
 327	list_for_each_entry(req, &fi->writepages, writepages_entry) {
 328		pgoff_t curr_index;
 329
 330		BUG_ON(req->inode != inode);
 331		curr_index = req->misc.write.in.offset >> PAGE_CACHE_SHIFT;
 332		if (curr_index == index) {
 333			found = true;
 334			break;
 335		}
 336	}
 337	spin_unlock(&fc->lock);
 338
 339	return found;
 340}
 341
 342/*
 343 * Wait for page writeback to be completed.
 344 *
 345 * Since fuse doesn't rely on the VM writeback tracking, this has to
 346 * use some other means.
 347 */
 348static int fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
 349{
 350	struct fuse_inode *fi = get_fuse_inode(inode);
 351
 352	wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
 353	return 0;
 354}
 355
 356static int fuse_flush(struct file *file, fl_owner_t id)
 357{
 358	struct inode *inode = file->f_path.dentry->d_inode;
 359	struct fuse_conn *fc = get_fuse_conn(inode);
 360	struct fuse_file *ff = file->private_data;
 361	struct fuse_req *req;
 362	struct fuse_flush_in inarg;
 363	int err;
 364
 365	if (is_bad_inode(inode))
 366		return -EIO;
 367
 368	if (fc->no_flush)
 369		return 0;
 370
 371	req = fuse_get_req_nofail(fc, file);
 372	memset(&inarg, 0, sizeof(inarg));
 373	inarg.fh = ff->fh;
 374	inarg.lock_owner = fuse_lock_owner_id(fc, id);
 375	req->in.h.opcode = FUSE_FLUSH;
 376	req->in.h.nodeid = get_node_id(inode);
 377	req->in.numargs = 1;
 378	req->in.args[0].size = sizeof(inarg);
 379	req->in.args[0].value = &inarg;
 380	req->force = 1;
 381	fuse_request_send(fc, req);
 382	err = req->out.h.error;
 383	fuse_put_request(fc, req);
 384	if (err == -ENOSYS) {
 385		fc->no_flush = 1;
 386		err = 0;
 387	}
 388	return err;
 389}
 390
 391/*
 392 * Wait for all pending writepages on the inode to finish.
 393 *
 394 * This is currently done by blocking further writes with FUSE_NOWRITE
 395 * and waiting for all sent writes to complete.
 396 *
 397 * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
 398 * could conflict with truncation.
 399 */
 400static void fuse_sync_writes(struct inode *inode)
 401{
 402	fuse_set_nowrite(inode);
 403	fuse_release_nowrite(inode);
 404}
 405
 406int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
 407		      int datasync, int isdir)
 408{
 409	struct inode *inode = file->f_mapping->host;
 410	struct fuse_conn *fc = get_fuse_conn(inode);
 411	struct fuse_file *ff = file->private_data;
 412	struct fuse_req *req;
 413	struct fuse_fsync_in inarg;
 414	int err;
 415
 416	if (is_bad_inode(inode))
 417		return -EIO;
 418
 419	err = filemap_write_and_wait_range(inode->i_mapping, start, end);
 420	if (err)
 421		return err;
 422
 423	if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
 424		return 0;
 425
 426	mutex_lock(&inode->i_mutex);
 427
 428	/*
 429	 * Start writeback against all dirty pages of the inode, then
 430	 * wait for all outstanding writes, before sending the FSYNC
 431	 * request.
 432	 */
 433	err = write_inode_now(inode, 0);
 434	if (err)
 435		goto out;
 436
 437	fuse_sync_writes(inode);
 438
 439	req = fuse_get_req(fc);
 440	if (IS_ERR(req)) {
 441		err = PTR_ERR(req);
 442		goto out;
 443	}
 444
 445	memset(&inarg, 0, sizeof(inarg));
 446	inarg.fh = ff->fh;
 447	inarg.fsync_flags = datasync ? 1 : 0;
 448	req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
 449	req->in.h.nodeid = get_node_id(inode);
 450	req->in.numargs = 1;
 451	req->in.args[0].size = sizeof(inarg);
 452	req->in.args[0].value = &inarg;
 453	fuse_request_send(fc, req);
 454	err = req->out.h.error;
 455	fuse_put_request(fc, req);
 456	if (err == -ENOSYS) {
 457		if (isdir)
 458			fc->no_fsyncdir = 1;
 459		else
 460			fc->no_fsync = 1;
 461		err = 0;
 462	}
 463out:
 464	mutex_unlock(&inode->i_mutex);
 465	return err;
 466}
 467
 468static int fuse_fsync(struct file *file, loff_t start, loff_t end,
 469		      int datasync)
 470{
 471	return fuse_fsync_common(file, start, end, datasync, 0);
 472}
 473
 474void fuse_read_fill(struct fuse_req *req, struct file *file, loff_t pos,
 475		    size_t count, int opcode)
 476{
 477	struct fuse_read_in *inarg = &req->misc.read.in;
 478	struct fuse_file *ff = file->private_data;
 479
 480	inarg->fh = ff->fh;
 481	inarg->offset = pos;
 482	inarg->size = count;
 483	inarg->flags = file->f_flags;
 484	req->in.h.opcode = opcode;
 485	req->in.h.nodeid = ff->nodeid;
 486	req->in.numargs = 1;
 487	req->in.args[0].size = sizeof(struct fuse_read_in);
 488	req->in.args[0].value = inarg;
 489	req->out.argvar = 1;
 490	req->out.numargs = 1;
 491	req->out.args[0].size = count;
 492}
 493
 494static size_t fuse_send_read(struct fuse_req *req, struct file *file,
 495			     loff_t pos, size_t count, fl_owner_t owner)
 496{
 497	struct fuse_file *ff = file->private_data;
 498	struct fuse_conn *fc = ff->fc;
 499
 500	fuse_read_fill(req, file, pos, count, FUSE_READ);
 501	if (owner != NULL) {
 502		struct fuse_read_in *inarg = &req->misc.read.in;
 503
 504		inarg->read_flags |= FUSE_READ_LOCKOWNER;
 505		inarg->lock_owner = fuse_lock_owner_id(fc, owner);
 506	}
 507	fuse_request_send(fc, req);
 508	return req->out.args[0].size;
 509}
 510
 511static void fuse_read_update_size(struct inode *inode, loff_t size,
 512				  u64 attr_ver)
 513{
 514	struct fuse_conn *fc = get_fuse_conn(inode);
 515	struct fuse_inode *fi = get_fuse_inode(inode);
 516
 517	spin_lock(&fc->lock);
 518	if (attr_ver == fi->attr_version && size < inode->i_size) {
 519		fi->attr_version = ++fc->attr_version;
 520		i_size_write(inode, size);
 521	}
 522	spin_unlock(&fc->lock);
 523}
 524
 525static int fuse_readpage(struct file *file, struct page *page)
 526{
 527	struct inode *inode = page->mapping->host;
 528	struct fuse_conn *fc = get_fuse_conn(inode);
 529	struct fuse_req *req;
 530	size_t num_read;
 531	loff_t pos = page_offset(page);
 532	size_t count = PAGE_CACHE_SIZE;
 533	u64 attr_ver;
 534	int err;
 535
 536	err = -EIO;
 537	if (is_bad_inode(inode))
 538		goto out;
 539
 540	/*
 541	 * Page writeback can extend beyond the lifetime of the
 542	 * page-cache page, so make sure we read a properly synced
 543	 * page.
 544	 */
 545	fuse_wait_on_page_writeback(inode, page->index);
 546
 547	req = fuse_get_req(fc);
 548	err = PTR_ERR(req);
 549	if (IS_ERR(req))
 550		goto out;
 551
 552	attr_ver = fuse_get_attr_version(fc);
 553
 554	req->out.page_zeroing = 1;
 555	req->out.argpages = 1;
 556	req->num_pages = 1;
 557	req->pages[0] = page;
 558	num_read = fuse_send_read(req, file, pos, count, NULL);
 559	err = req->out.h.error;
 560	fuse_put_request(fc, req);
 561
 562	if (!err) {
 563		/*
 564		 * Short read means EOF.  If file size is larger, truncate it
 565		 */
 566		if (num_read < count)
 567			fuse_read_update_size(inode, pos + num_read, attr_ver);
 568
 569		SetPageUptodate(page);
 570	}
 571
 572	fuse_invalidate_attr(inode); /* atime changed */
 573 out:
 574	unlock_page(page);
 575	return err;
 576}
 577
 578static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
 579{
 580	int i;
 581	size_t count = req->misc.read.in.size;
 582	size_t num_read = req->out.args[0].size;
 583	struct address_space *mapping = NULL;
 584
 585	for (i = 0; mapping == NULL && i < req->num_pages; i++)
 586		mapping = req->pages[i]->mapping;
 587
 588	if (mapping) {
 589		struct inode *inode = mapping->host;
 590
 591		/*
 592		 * Short read means EOF. If file size is larger, truncate it
 593		 */
 594		if (!req->out.h.error && num_read < count) {
 595			loff_t pos;
 596
 597			pos = page_offset(req->pages[0]) + num_read;
 598			fuse_read_update_size(inode, pos,
 599					      req->misc.read.attr_ver);
 600		}
 601		fuse_invalidate_attr(inode); /* atime changed */
 602	}
 603
 604	for (i = 0; i < req->num_pages; i++) {
 605		struct page *page = req->pages[i];
 606		if (!req->out.h.error)
 607			SetPageUptodate(page);
 608		else
 609			SetPageError(page);
 610		unlock_page(page);
 611		page_cache_release(page);
 612	}
 613	if (req->ff)
 614		fuse_file_put(req->ff, false);
 615}
 616
 617static void fuse_send_readpages(struct fuse_req *req, struct file *file)
 618{
 619	struct fuse_file *ff = file->private_data;
 620	struct fuse_conn *fc = ff->fc;
 621	loff_t pos = page_offset(req->pages[0]);
 622	size_t count = req->num_pages << PAGE_CACHE_SHIFT;
 623
 624	req->out.argpages = 1;
 625	req->out.page_zeroing = 1;
 626	req->out.page_replace = 1;
 627	fuse_read_fill(req, file, pos, count, FUSE_READ);
 628	req->misc.read.attr_ver = fuse_get_attr_version(fc);
 629	if (fc->async_read) {
 630		req->ff = fuse_file_get(ff);
 631		req->end = fuse_readpages_end;
 632		fuse_request_send_background(fc, req);
 633	} else {
 634		fuse_request_send(fc, req);
 635		fuse_readpages_end(fc, req);
 636		fuse_put_request(fc, req);
 637	}
 638}
 639
 640struct fuse_fill_data {
 641	struct fuse_req *req;
 642	struct file *file;
 643	struct inode *inode;
 644};
 645
 646static int fuse_readpages_fill(void *_data, struct page *page)
 647{
 648	struct fuse_fill_data *data = _data;
 649	struct fuse_req *req = data->req;
 650	struct inode *inode = data->inode;
 651	struct fuse_conn *fc = get_fuse_conn(inode);
 652
 653	fuse_wait_on_page_writeback(inode, page->index);
 654
 655	if (req->num_pages &&
 656	    (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
 657	     (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
 658	     req->pages[req->num_pages - 1]->index + 1 != page->index)) {
 659		fuse_send_readpages(req, data->file);
 660		data->req = req = fuse_get_req(fc);
 661		if (IS_ERR(req)) {
 662			unlock_page(page);
 663			return PTR_ERR(req);
 664		}
 665	}
 666	page_cache_get(page);
 667	req->pages[req->num_pages] = page;
 668	req->num_pages++;
 669	return 0;
 670}
 671
 672static int fuse_readpages(struct file *file, struct address_space *mapping,
 673			  struct list_head *pages, unsigned nr_pages)
 674{
 675	struct inode *inode = mapping->host;
 676	struct fuse_conn *fc = get_fuse_conn(inode);
 677	struct fuse_fill_data data;
 678	int err;
 679
 680	err = -EIO;
 681	if (is_bad_inode(inode))
 682		goto out;
 683
 684	data.file = file;
 685	data.inode = inode;
 686	data.req = fuse_get_req(fc);
 687	err = PTR_ERR(data.req);
 688	if (IS_ERR(data.req))
 689		goto out;
 690
 691	err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
 692	if (!err) {
 693		if (data.req->num_pages)
 694			fuse_send_readpages(data.req, file);
 695		else
 696			fuse_put_request(fc, data.req);
 697	}
 698out:
 699	return err;
 700}
 701
 702static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
 703				  unsigned long nr_segs, loff_t pos)
 704{
 705	struct inode *inode = iocb->ki_filp->f_mapping->host;
 706
 707	if (pos + iov_length(iov, nr_segs) > i_size_read(inode)) {
 708		int err;
 709		/*
 710		 * If trying to read past EOF, make sure the i_size
 711		 * attribute is up-to-date.
 712		 */
 713		err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL);
 714		if (err)
 715			return err;
 716	}
 717
 718	return generic_file_aio_read(iocb, iov, nr_segs, pos);
 719}
 720
 721static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
 722			    loff_t pos, size_t count)
 723{
 724	struct fuse_write_in *inarg = &req->misc.write.in;
 725	struct fuse_write_out *outarg = &req->misc.write.out;
 726
 727	inarg->fh = ff->fh;
 728	inarg->offset = pos;
 729	inarg->size = count;
 730	req->in.h.opcode = FUSE_WRITE;
 731	req->in.h.nodeid = ff->nodeid;
 732	req->in.numargs = 2;
 733	if (ff->fc->minor < 9)
 734		req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
 735	else
 736		req->in.args[0].size = sizeof(struct fuse_write_in);
 737	req->in.args[0].value = inarg;
 738	req->in.args[1].size = count;
 739	req->out.numargs = 1;
 740	req->out.args[0].size = sizeof(struct fuse_write_out);
 741	req->out.args[0].value = outarg;
 742}
 743
 744static size_t fuse_send_write(struct fuse_req *req, struct file *file,
 745			      loff_t pos, size_t count, fl_owner_t owner)
 746{
 747	struct fuse_file *ff = file->private_data;
 748	struct fuse_conn *fc = ff->fc;
 749	struct fuse_write_in *inarg = &req->misc.write.in;
 750
 751	fuse_write_fill(req, ff, pos, count);
 752	inarg->flags = file->f_flags;
 753	if (owner != NULL) {
 754		inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
 755		inarg->lock_owner = fuse_lock_owner_id(fc, owner);
 756	}
 757	fuse_request_send(fc, req);
 758	return req->misc.write.out.size;
 759}
 760
 761void fuse_write_update_size(struct inode *inode, loff_t pos)
 762{
 763	struct fuse_conn *fc = get_fuse_conn(inode);
 764	struct fuse_inode *fi = get_fuse_inode(inode);
 765
 766	spin_lock(&fc->lock);
 767	fi->attr_version = ++fc->attr_version;
 768	if (pos > inode->i_size)
 769		i_size_write(inode, pos);
 770	spin_unlock(&fc->lock);
 771}
 772
 773static size_t fuse_send_write_pages(struct fuse_req *req, struct file *file,
 774				    struct inode *inode, loff_t pos,
 775				    size_t count)
 776{
 777	size_t res;
 778	unsigned offset;
 779	unsigned i;
 780
 781	for (i = 0; i < req->num_pages; i++)
 782		fuse_wait_on_page_writeback(inode, req->pages[i]->index);
 783
 784	res = fuse_send_write(req, file, pos, count, NULL);
 785
 786	offset = req->page_offset;
 787	count = res;
 788	for (i = 0; i < req->num_pages; i++) {
 789		struct page *page = req->pages[i];
 790
 791		if (!req->out.h.error && !offset && count >= PAGE_CACHE_SIZE)
 792			SetPageUptodate(page);
 793
 794		if (count > PAGE_CACHE_SIZE - offset)
 795			count -= PAGE_CACHE_SIZE - offset;
 796		else
 797			count = 0;
 798		offset = 0;
 799
 800		unlock_page(page);
 801		page_cache_release(page);
 802	}
 803
 804	return res;
 805}
 806
 807static ssize_t fuse_fill_write_pages(struct fuse_req *req,
 808			       struct address_space *mapping,
 809			       struct iov_iter *ii, loff_t pos)
 810{
 811	struct fuse_conn *fc = get_fuse_conn(mapping->host);
 812	unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 813	size_t count = 0;
 814	int err;
 815
 816	req->in.argpages = 1;
 817	req->page_offset = offset;
 818
 819	do {
 820		size_t tmp;
 821		struct page *page;
 822		pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 823		size_t bytes = min_t(size_t, PAGE_CACHE_SIZE - offset,
 824				     iov_iter_count(ii));
 825
 826		bytes = min_t(size_t, bytes, fc->max_write - count);
 827
 828 again:
 829		err = -EFAULT;
 830		if (iov_iter_fault_in_readable(ii, bytes))
 831			break;
 832
 833		err = -ENOMEM;
 834		page = grab_cache_page_write_begin(mapping, index, 0);
 835		if (!page)
 836			break;
 837
 838		if (mapping_writably_mapped(mapping))
 839			flush_dcache_page(page);
 840
 841		pagefault_disable();
 842		tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes);
 843		pagefault_enable();
 844		flush_dcache_page(page);
 845
 846		mark_page_accessed(page);
 847
 848		if (!tmp) {
 849			unlock_page(page);
 850			page_cache_release(page);
 851			bytes = min(bytes, iov_iter_single_seg_count(ii));
 852			goto again;
 853		}
 854
 855		err = 0;
 856		req->pages[req->num_pages] = page;
 857		req->num_pages++;
 858
 859		iov_iter_advance(ii, tmp);
 860		count += tmp;
 861		pos += tmp;
 862		offset += tmp;
 863		if (offset == PAGE_CACHE_SIZE)
 864			offset = 0;
 865
 866		if (!fc->big_writes)
 867			break;
 868	} while (iov_iter_count(ii) && count < fc->max_write &&
 869		 req->num_pages < FUSE_MAX_PAGES_PER_REQ && offset == 0);
 870
 871	return count > 0 ? count : err;
 872}
 873
 874static ssize_t fuse_perform_write(struct file *file,
 875				  struct address_space *mapping,
 876				  struct iov_iter *ii, loff_t pos)
 877{
 878	struct inode *inode = mapping->host;
 879	struct fuse_conn *fc = get_fuse_conn(inode);
 880	int err = 0;
 881	ssize_t res = 0;
 882
 883	if (is_bad_inode(inode))
 884		return -EIO;
 885
 886	do {
 887		struct fuse_req *req;
 888		ssize_t count;
 889
 890		req = fuse_get_req(fc);
 891		if (IS_ERR(req)) {
 892			err = PTR_ERR(req);
 893			break;
 894		}
 895
 896		count = fuse_fill_write_pages(req, mapping, ii, pos);
 897		if (count <= 0) {
 898			err = count;
 899		} else {
 900			size_t num_written;
 901
 902			num_written = fuse_send_write_pages(req, file, inode,
 903							    pos, count);
 904			err = req->out.h.error;
 905			if (!err) {
 906				res += num_written;
 907				pos += num_written;
 908
 909				/* break out of the loop on short write */
 910				if (num_written != count)
 911					err = -EIO;
 912			}
 913		}
 914		fuse_put_request(fc, req);
 915	} while (!err && iov_iter_count(ii));
 916
 917	if (res > 0)
 918		fuse_write_update_size(inode, pos);
 919
 920	fuse_invalidate_attr(inode);
 921
 922	return res > 0 ? res : err;
 923}
 924
 925static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 926				   unsigned long nr_segs, loff_t pos)
 927{
 928	struct file *file = iocb->ki_filp;
 929	struct address_space *mapping = file->f_mapping;
 930	size_t count = 0;
 931	size_t ocount = 0;
 932	ssize_t written = 0;
 933	ssize_t written_buffered = 0;
 934	struct inode *inode = mapping->host;
 935	ssize_t err;
 936	struct iov_iter i;
 937	loff_t endbyte = 0;
 938
 939	WARN_ON(iocb->ki_pos != pos);
 940
 941	ocount = 0;
 942	err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
 943	if (err)
 944		return err;
 945
 946	count = ocount;
 947
 948	mutex_lock(&inode->i_mutex);
 949	vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
 950
 951	/* We can write back this queue in page reclaim */
 952	current->backing_dev_info = mapping->backing_dev_info;
 953
 954	err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
 955	if (err)
 956		goto out;
 957
 958	if (count == 0)
 959		goto out;
 960
 961	err = file_remove_suid(file);
 962	if (err)
 963		goto out;
 964
 965	err = file_update_time(file);
 966	if (err)
 967		goto out;
 968
 969	if (file->f_flags & O_DIRECT) {
 970		written = generic_file_direct_write(iocb, iov, &nr_segs,
 971						    pos, &iocb->ki_pos,
 972						    count, ocount);
 973		if (written < 0 || written == count)
 974			goto out;
 975
 976		pos += written;
 977		count -= written;
 978
 979		iov_iter_init(&i, iov, nr_segs, count, written);
 980		written_buffered = fuse_perform_write(file, mapping, &i, pos);
 981		if (written_buffered < 0) {
 982			err = written_buffered;
 983			goto out;
 984		}
 985		endbyte = pos + written_buffered - 1;
 986
 987		err = filemap_write_and_wait_range(file->f_mapping, pos,
 988						   endbyte);
 989		if (err)
 990			goto out;
 991
 992		invalidate_mapping_pages(file->f_mapping,
 993					 pos >> PAGE_CACHE_SHIFT,
 994					 endbyte >> PAGE_CACHE_SHIFT);
 
 995
 996		written += written_buffered;
 997		iocb->ki_pos = pos + written_buffered;
 998	} else {
 999		iov_iter_init(&i, iov, nr_segs, count, 0);
1000		written = fuse_perform_write(file, mapping, &i, pos);
1001		if (written >= 0)
1002			iocb->ki_pos = pos + written;
1003	}
1004out:
1005	current->backing_dev_info = NULL;
1006	mutex_unlock(&inode->i_mutex);
1007
1008	return written ? written : err;
1009}
1010
1011static void fuse_release_user_pages(struct fuse_req *req, int write)
1012{
1013	unsigned i;
1014
1015	for (i = 0; i < req->num_pages; i++) {
1016		struct page *page = req->pages[i];
1017		if (write)
1018			set_page_dirty_lock(page);
1019		put_page(page);
1020	}
1021}
1022
1023static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
1024			       size_t *nbytesp, int write)
1025{
1026	size_t nbytes = *nbytesp;
1027	unsigned long user_addr = (unsigned long) buf;
1028	unsigned offset = user_addr & ~PAGE_MASK;
1029	int npages;
1030
1031	/* Special case for kernel I/O: can copy directly into the buffer */
1032	if (segment_eq(get_fs(), KERNEL_DS)) {
1033		if (write)
1034			req->in.args[1].value = (void *) user_addr;
1035		else
1036			req->out.args[0].value = (void *) user_addr;
1037
1038		return 0;
1039	}
1040
1041	nbytes = min_t(size_t, nbytes, FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
1042	npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1043	npages = clamp(npages, 1, FUSE_MAX_PAGES_PER_REQ);
1044	npages = get_user_pages_fast(user_addr, npages, !write, req->pages);
1045	if (npages < 0)
1046		return npages;
1047
1048	req->num_pages = npages;
1049	req->page_offset = offset;
1050
1051	if (write)
1052		req->in.argpages = 1;
1053	else
1054		req->out.argpages = 1;
1055
1056	nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset;
1057	*nbytesp = min(*nbytesp, nbytes);
1058
1059	return 0;
1060}
1061
1062ssize_t fuse_direct_io(struct file *file, const char __user *buf,
1063		       size_t count, loff_t *ppos, int write)
1064{
1065	struct fuse_file *ff = file->private_data;
1066	struct fuse_conn *fc = ff->fc;
1067	size_t nmax = write ? fc->max_write : fc->max_read;
1068	loff_t pos = *ppos;
1069	ssize_t res = 0;
1070	struct fuse_req *req;
1071
1072	req = fuse_get_req(fc);
1073	if (IS_ERR(req))
1074		return PTR_ERR(req);
1075
1076	while (count) {
1077		size_t nres;
1078		fl_owner_t owner = current->files;
1079		size_t nbytes = min(count, nmax);
1080		int err = fuse_get_user_pages(req, buf, &nbytes, write);
1081		if (err) {
1082			res = err;
1083			break;
1084		}
1085
1086		if (write)
1087			nres = fuse_send_write(req, file, pos, nbytes, owner);
1088		else
1089			nres = fuse_send_read(req, file, pos, nbytes, owner);
1090
1091		fuse_release_user_pages(req, !write);
1092		if (req->out.h.error) {
1093			if (!res)
1094				res = req->out.h.error;
1095			break;
1096		} else if (nres > nbytes) {
1097			res = -EIO;
1098			break;
1099		}
1100		count -= nres;
1101		res += nres;
1102		pos += nres;
1103		buf += nres;
1104		if (nres != nbytes)
1105			break;
1106		if (count) {
1107			fuse_put_request(fc, req);
1108			req = fuse_get_req(fc);
1109			if (IS_ERR(req))
1110				break;
1111		}
1112	}
1113	if (!IS_ERR(req))
1114		fuse_put_request(fc, req);
1115	if (res > 0)
1116		*ppos = pos;
1117
1118	return res;
1119}
1120EXPORT_SYMBOL_GPL(fuse_direct_io);
1121
1122static ssize_t fuse_direct_read(struct file *file, char __user *buf,
1123				     size_t count, loff_t *ppos)
1124{
1125	ssize_t res;
1126	struct inode *inode = file->f_path.dentry->d_inode;
1127
1128	if (is_bad_inode(inode))
1129		return -EIO;
1130
1131	res = fuse_direct_io(file, buf, count, ppos, 0);
1132
1133	fuse_invalidate_attr(inode);
1134
1135	return res;
1136}
1137
1138static ssize_t __fuse_direct_write(struct file *file, const char __user *buf,
1139				   size_t count, loff_t *ppos)
1140{
1141	struct inode *inode = file->f_path.dentry->d_inode;
1142	ssize_t res;
1143
1144	res = generic_write_checks(file, ppos, &count, 0);
1145	if (!res) {
1146		res = fuse_direct_io(file, buf, count, ppos, 1);
1147		if (res > 0)
1148			fuse_write_update_size(inode, *ppos);
1149	}
1150
1151	fuse_invalidate_attr(inode);
1152
1153	return res;
1154}
1155
1156static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
1157				 size_t count, loff_t *ppos)
1158{
1159	struct inode *inode = file->f_path.dentry->d_inode;
1160	ssize_t res;
1161
1162	if (is_bad_inode(inode))
1163		return -EIO;
1164
1165	/* Don't allow parallel writes to the same file */
1166	mutex_lock(&inode->i_mutex);
1167	res = __fuse_direct_write(file, buf, count, ppos);
 
 
 
 
 
1168	mutex_unlock(&inode->i_mutex);
1169
 
 
1170	return res;
1171}
1172
1173static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
1174{
1175	__free_page(req->pages[0]);
1176	fuse_file_put(req->ff, false);
1177}
1178
1179static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
1180{
1181	struct inode *inode = req->inode;
1182	struct fuse_inode *fi = get_fuse_inode(inode);
1183	struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
1184
1185	list_del(&req->writepages_entry);
1186	dec_bdi_stat(bdi, BDI_WRITEBACK);
1187	dec_zone_page_state(req->pages[0], NR_WRITEBACK_TEMP);
1188	bdi_writeout_inc(bdi);
1189	wake_up(&fi->page_waitq);
1190}
1191
1192/* Called under fc->lock, may release and reacquire it */
1193static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req)
1194__releases(fc->lock)
1195__acquires(fc->lock)
1196{
1197	struct fuse_inode *fi = get_fuse_inode(req->inode);
1198	loff_t size = i_size_read(req->inode);
1199	struct fuse_write_in *inarg = &req->misc.write.in;
1200
1201	if (!fc->connected)
1202		goto out_free;
1203
1204	if (inarg->offset + PAGE_CACHE_SIZE <= size) {
1205		inarg->size = PAGE_CACHE_SIZE;
1206	} else if (inarg->offset < size) {
1207		inarg->size = size & (PAGE_CACHE_SIZE - 1);
1208	} else {
1209		/* Got truncated off completely */
1210		goto out_free;
1211	}
1212
1213	req->in.args[1].size = inarg->size;
1214	fi->writectr++;
1215	fuse_request_send_background_locked(fc, req);
1216	return;
1217
1218 out_free:
1219	fuse_writepage_finish(fc, req);
1220	spin_unlock(&fc->lock);
1221	fuse_writepage_free(fc, req);
1222	fuse_put_request(fc, req);
1223	spin_lock(&fc->lock);
1224}
1225
1226/*
1227 * If fi->writectr is positive (no truncate or fsync going on) send
1228 * all queued writepage requests.
1229 *
1230 * Called with fc->lock
1231 */
1232void fuse_flush_writepages(struct inode *inode)
1233__releases(fc->lock)
1234__acquires(fc->lock)
1235{
1236	struct fuse_conn *fc = get_fuse_conn(inode);
1237	struct fuse_inode *fi = get_fuse_inode(inode);
1238	struct fuse_req *req;
1239
1240	while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
1241		req = list_entry(fi->queued_writes.next, struct fuse_req, list);
1242		list_del_init(&req->list);
1243		fuse_send_writepage(fc, req);
1244	}
1245}
1246
1247static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req)
1248{
1249	struct inode *inode = req->inode;
1250	struct fuse_inode *fi = get_fuse_inode(inode);
1251
1252	mapping_set_error(inode->i_mapping, req->out.h.error);
1253	spin_lock(&fc->lock);
1254	fi->writectr--;
1255	fuse_writepage_finish(fc, req);
1256	spin_unlock(&fc->lock);
1257	fuse_writepage_free(fc, req);
1258}
1259
1260static int fuse_writepage_locked(struct page *page)
1261{
1262	struct address_space *mapping = page->mapping;
1263	struct inode *inode = mapping->host;
1264	struct fuse_conn *fc = get_fuse_conn(inode);
1265	struct fuse_inode *fi = get_fuse_inode(inode);
1266	struct fuse_req *req;
1267	struct fuse_file *ff;
1268	struct page *tmp_page;
1269
1270	set_page_writeback(page);
1271
1272	req = fuse_request_alloc_nofs();
1273	if (!req)
1274		goto err;
1275
1276	tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1277	if (!tmp_page)
1278		goto err_free;
1279
1280	spin_lock(&fc->lock);
1281	BUG_ON(list_empty(&fi->write_files));
1282	ff = list_entry(fi->write_files.next, struct fuse_file, write_entry);
1283	req->ff = fuse_file_get(ff);
1284	spin_unlock(&fc->lock);
1285
1286	fuse_write_fill(req, ff, page_offset(page), 0);
1287
1288	copy_highpage(tmp_page, page);
1289	req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
1290	req->in.argpages = 1;
1291	req->num_pages = 1;
1292	req->pages[0] = tmp_page;
1293	req->page_offset = 0;
1294	req->end = fuse_writepage_end;
1295	req->inode = inode;
1296
1297	inc_bdi_stat(mapping->backing_dev_info, BDI_WRITEBACK);
1298	inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
1299	end_page_writeback(page);
1300
1301	spin_lock(&fc->lock);
1302	list_add(&req->writepages_entry, &fi->writepages);
1303	list_add_tail(&req->list, &fi->queued_writes);
1304	fuse_flush_writepages(inode);
1305	spin_unlock(&fc->lock);
1306
1307	return 0;
1308
1309err_free:
1310	fuse_request_free(req);
1311err:
1312	end_page_writeback(page);
1313	return -ENOMEM;
1314}
1315
1316static int fuse_writepage(struct page *page, struct writeback_control *wbc)
1317{
1318	int err;
1319
1320	err = fuse_writepage_locked(page);
1321	unlock_page(page);
1322
1323	return err;
1324}
1325
1326static int fuse_launder_page(struct page *page)
1327{
1328	int err = 0;
1329	if (clear_page_dirty_for_io(page)) {
1330		struct inode *inode = page->mapping->host;
1331		err = fuse_writepage_locked(page);
1332		if (!err)
1333			fuse_wait_on_page_writeback(inode, page->index);
1334	}
1335	return err;
1336}
1337
1338/*
1339 * Write back dirty pages now, because there may not be any suitable
1340 * open files later
1341 */
1342static void fuse_vma_close(struct vm_area_struct *vma)
1343{
1344	filemap_write_and_wait(vma->vm_file->f_mapping);
1345}
1346
1347/*
1348 * Wait for writeback against this page to complete before allowing it
1349 * to be marked dirty again, and hence written back again, possibly
1350 * before the previous writepage completed.
1351 *
1352 * Block here, instead of in ->writepage(), so that the userspace fs
1353 * can only block processes actually operating on the filesystem.
1354 *
1355 * Otherwise unprivileged userspace fs would be able to block
1356 * unrelated:
1357 *
1358 * - page migration
1359 * - sync(2)
1360 * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
1361 */
1362static int fuse_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
1363{
1364	struct page *page = vmf->page;
1365	/*
1366	 * Don't use page->mapping as it may become NULL from a
1367	 * concurrent truncate.
1368	 */
1369	struct inode *inode = vma->vm_file->f_mapping->host;
1370
1371	fuse_wait_on_page_writeback(inode, page->index);
1372	return 0;
1373}
1374
1375static const struct vm_operations_struct fuse_file_vm_ops = {
1376	.close		= fuse_vma_close,
1377	.fault		= filemap_fault,
1378	.page_mkwrite	= fuse_page_mkwrite,
1379};
1380
1381static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
1382{
1383	if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) {
1384		struct inode *inode = file->f_dentry->d_inode;
1385		struct fuse_conn *fc = get_fuse_conn(inode);
1386		struct fuse_inode *fi = get_fuse_inode(inode);
1387		struct fuse_file *ff = file->private_data;
1388		/*
1389		 * file may be written through mmap, so chain it onto the
1390		 * inodes's write_file list
1391		 */
1392		spin_lock(&fc->lock);
1393		if (list_empty(&ff->write_entry))
1394			list_add(&ff->write_entry, &fi->write_files);
1395		spin_unlock(&fc->lock);
1396	}
1397	file_accessed(file);
1398	vma->vm_ops = &fuse_file_vm_ops;
1399	return 0;
1400}
1401
1402static int fuse_direct_mmap(struct file *file, struct vm_area_struct *vma)
1403{
1404	/* Can't provide the coherency needed for MAP_SHARED */
1405	if (vma->vm_flags & VM_MAYSHARE)
1406		return -ENODEV;
1407
1408	invalidate_inode_pages2(file->f_mapping);
1409
1410	return generic_file_mmap(file, vma);
1411}
1412
1413static int convert_fuse_file_lock(const struct fuse_file_lock *ffl,
1414				  struct file_lock *fl)
1415{
1416	switch (ffl->type) {
1417	case F_UNLCK:
1418		break;
1419
1420	case F_RDLCK:
1421	case F_WRLCK:
1422		if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
1423		    ffl->end < ffl->start)
1424			return -EIO;
1425
1426		fl->fl_start = ffl->start;
1427		fl->fl_end = ffl->end;
1428		fl->fl_pid = ffl->pid;
1429		break;
1430
1431	default:
1432		return -EIO;
1433	}
1434	fl->fl_type = ffl->type;
1435	return 0;
1436}
1437
1438static void fuse_lk_fill(struct fuse_req *req, struct file *file,
1439			 const struct file_lock *fl, int opcode, pid_t pid,
1440			 int flock)
1441{
1442	struct inode *inode = file->f_path.dentry->d_inode;
1443	struct fuse_conn *fc = get_fuse_conn(inode);
1444	struct fuse_file *ff = file->private_data;
1445	struct fuse_lk_in *arg = &req->misc.lk_in;
1446
1447	arg->fh = ff->fh;
1448	arg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
1449	arg->lk.start = fl->fl_start;
1450	arg->lk.end = fl->fl_end;
1451	arg->lk.type = fl->fl_type;
1452	arg->lk.pid = pid;
1453	if (flock)
1454		arg->lk_flags |= FUSE_LK_FLOCK;
1455	req->in.h.opcode = opcode;
1456	req->in.h.nodeid = get_node_id(inode);
1457	req->in.numargs = 1;
1458	req->in.args[0].size = sizeof(*arg);
1459	req->in.args[0].value = arg;
1460}
1461
1462static int fuse_getlk(struct file *file, struct file_lock *fl)
1463{
1464	struct inode *inode = file->f_path.dentry->d_inode;
1465	struct fuse_conn *fc = get_fuse_conn(inode);
1466	struct fuse_req *req;
1467	struct fuse_lk_out outarg;
1468	int err;
1469
1470	req = fuse_get_req(fc);
1471	if (IS_ERR(req))
1472		return PTR_ERR(req);
1473
1474	fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0);
1475	req->out.numargs = 1;
1476	req->out.args[0].size = sizeof(outarg);
1477	req->out.args[0].value = &outarg;
1478	fuse_request_send(fc, req);
1479	err = req->out.h.error;
1480	fuse_put_request(fc, req);
1481	if (!err)
1482		err = convert_fuse_file_lock(&outarg.lk, fl);
1483
1484	return err;
1485}
1486
1487static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
1488{
1489	struct inode *inode = file->f_path.dentry->d_inode;
1490	struct fuse_conn *fc = get_fuse_conn(inode);
1491	struct fuse_req *req;
1492	int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
1493	pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0;
1494	int err;
1495
1496	if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
1497		/* NLM needs asynchronous locks, which we don't support yet */
1498		return -ENOLCK;
1499	}
1500
1501	/* Unlock on close is handled by the flush method */
1502	if (fl->fl_flags & FL_CLOSE)
1503		return 0;
1504
1505	req = fuse_get_req(fc);
1506	if (IS_ERR(req))
1507		return PTR_ERR(req);
1508
1509	fuse_lk_fill(req, file, fl, opcode, pid, flock);
1510	fuse_request_send(fc, req);
1511	err = req->out.h.error;
1512	/* locking is restartable */
1513	if (err == -EINTR)
1514		err = -ERESTARTSYS;
1515	fuse_put_request(fc, req);
1516	return err;
1517}
1518
1519static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
1520{
1521	struct inode *inode = file->f_path.dentry->d_inode;
1522	struct fuse_conn *fc = get_fuse_conn(inode);
1523	int err;
1524
1525	if (cmd == F_CANCELLK) {
1526		err = 0;
1527	} else if (cmd == F_GETLK) {
1528		if (fc->no_lock) {
1529			posix_test_lock(file, fl);
1530			err = 0;
1531		} else
1532			err = fuse_getlk(file, fl);
1533	} else {
1534		if (fc->no_lock)
1535			err = posix_lock_file(file, fl, NULL);
1536		else
1537			err = fuse_setlk(file, fl, 0);
1538	}
1539	return err;
1540}
1541
1542static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
1543{
1544	struct inode *inode = file->f_path.dentry->d_inode;
1545	struct fuse_conn *fc = get_fuse_conn(inode);
1546	int err;
1547
1548	if (fc->no_flock) {
1549		err = flock_lock_file_wait(file, fl);
1550	} else {
1551		struct fuse_file *ff = file->private_data;
1552
1553		/* emulate flock with POSIX locks */
1554		fl->fl_owner = (fl_owner_t) file;
1555		ff->flock = true;
1556		err = fuse_setlk(file, fl, 1);
1557	}
1558
1559	return err;
1560}
1561
1562static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
1563{
1564	struct inode *inode = mapping->host;
1565	struct fuse_conn *fc = get_fuse_conn(inode);
1566	struct fuse_req *req;
1567	struct fuse_bmap_in inarg;
1568	struct fuse_bmap_out outarg;
1569	int err;
1570
1571	if (!inode->i_sb->s_bdev || fc->no_bmap)
1572		return 0;
1573
1574	req = fuse_get_req(fc);
1575	if (IS_ERR(req))
1576		return 0;
1577
1578	memset(&inarg, 0, sizeof(inarg));
1579	inarg.block = block;
1580	inarg.blocksize = inode->i_sb->s_blocksize;
1581	req->in.h.opcode = FUSE_BMAP;
1582	req->in.h.nodeid = get_node_id(inode);
1583	req->in.numargs = 1;
1584	req->in.args[0].size = sizeof(inarg);
1585	req->in.args[0].value = &inarg;
1586	req->out.numargs = 1;
1587	req->out.args[0].size = sizeof(outarg);
1588	req->out.args[0].value = &outarg;
1589	fuse_request_send(fc, req);
1590	err = req->out.h.error;
1591	fuse_put_request(fc, req);
1592	if (err == -ENOSYS)
1593		fc->no_bmap = 1;
1594
1595	return err ? 0 : outarg.block;
1596}
1597
1598static loff_t fuse_file_llseek(struct file *file, loff_t offset, int origin)
1599{
1600	loff_t retval;
1601	struct inode *inode = file->f_path.dentry->d_inode;
1602
1603	/* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
1604	if (origin == SEEK_CUR || origin == SEEK_SET)
1605		return generic_file_llseek(file, offset, origin);
1606
1607	mutex_lock(&inode->i_mutex);
1608	retval = fuse_update_attributes(inode, NULL, file, NULL);
1609	if (!retval)
1610		retval = generic_file_llseek(file, offset, origin);
1611	mutex_unlock(&inode->i_mutex);
 
1612
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1613	return retval;
1614}
1615
1616static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov,
1617			unsigned int nr_segs, size_t bytes, bool to_user)
1618{
1619	struct iov_iter ii;
1620	int page_idx = 0;
1621
1622	if (!bytes)
1623		return 0;
1624
1625	iov_iter_init(&ii, iov, nr_segs, bytes, 0);
1626
1627	while (iov_iter_count(&ii)) {
1628		struct page *page = pages[page_idx++];
1629		size_t todo = min_t(size_t, PAGE_SIZE, iov_iter_count(&ii));
1630		void *kaddr;
1631
1632		kaddr = kmap(page);
1633
1634		while (todo) {
1635			char __user *uaddr = ii.iov->iov_base + ii.iov_offset;
1636			size_t iov_len = ii.iov->iov_len - ii.iov_offset;
1637			size_t copy = min(todo, iov_len);
1638			size_t left;
1639
1640			if (!to_user)
1641				left = copy_from_user(kaddr, uaddr, copy);
1642			else
1643				left = copy_to_user(uaddr, kaddr, copy);
1644
1645			if (unlikely(left))
1646				return -EFAULT;
1647
1648			iov_iter_advance(&ii, copy);
1649			todo -= copy;
1650			kaddr += copy;
1651		}
1652
1653		kunmap(page);
1654	}
1655
1656	return 0;
1657}
1658
1659/*
1660 * CUSE servers compiled on 32bit broke on 64bit kernels because the
1661 * ABI was defined to be 'struct iovec' which is different on 32bit
1662 * and 64bit.  Fortunately we can determine which structure the server
1663 * used from the size of the reply.
1664 */
1665static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src,
1666				     size_t transferred, unsigned count,
1667				     bool is_compat)
1668{
1669#ifdef CONFIG_COMPAT
1670	if (count * sizeof(struct compat_iovec) == transferred) {
1671		struct compat_iovec *ciov = src;
1672		unsigned i;
1673
1674		/*
1675		 * With this interface a 32bit server cannot support
1676		 * non-compat (i.e. ones coming from 64bit apps) ioctl
1677		 * requests
1678		 */
1679		if (!is_compat)
1680			return -EINVAL;
1681
1682		for (i = 0; i < count; i++) {
1683			dst[i].iov_base = compat_ptr(ciov[i].iov_base);
1684			dst[i].iov_len = ciov[i].iov_len;
1685		}
1686		return 0;
1687	}
1688#endif
1689
1690	if (count * sizeof(struct iovec) != transferred)
1691		return -EIO;
1692
1693	memcpy(dst, src, transferred);
1694	return 0;
1695}
1696
1697/* Make sure iov_length() won't overflow */
1698static int fuse_verify_ioctl_iov(struct iovec *iov, size_t count)
1699{
1700	size_t n;
1701	u32 max = FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT;
1702
1703	for (n = 0; n < count; n++, iov++) {
1704		if (iov->iov_len > (size_t) max)
1705			return -ENOMEM;
1706		max -= iov->iov_len;
1707	}
1708	return 0;
1709}
1710
1711static int fuse_copy_ioctl_iovec(struct fuse_conn *fc, struct iovec *dst,
1712				 void *src, size_t transferred, unsigned count,
1713				 bool is_compat)
1714{
1715	unsigned i;
1716	struct fuse_ioctl_iovec *fiov = src;
1717
1718	if (fc->minor < 16) {
1719		return fuse_copy_ioctl_iovec_old(dst, src, transferred,
1720						 count, is_compat);
1721	}
1722
1723	if (count * sizeof(struct fuse_ioctl_iovec) != transferred)
1724		return -EIO;
1725
1726	for (i = 0; i < count; i++) {
1727		/* Did the server supply an inappropriate value? */
1728		if (fiov[i].base != (unsigned long) fiov[i].base ||
1729		    fiov[i].len != (unsigned long) fiov[i].len)
1730			return -EIO;
1731
1732		dst[i].iov_base = (void __user *) (unsigned long) fiov[i].base;
1733		dst[i].iov_len = (size_t) fiov[i].len;
1734
1735#ifdef CONFIG_COMPAT
1736		if (is_compat &&
1737		    (ptr_to_compat(dst[i].iov_base) != fiov[i].base ||
1738		     (compat_size_t) dst[i].iov_len != fiov[i].len))
1739			return -EIO;
1740#endif
1741	}
1742
1743	return 0;
1744}
1745
1746
1747/*
1748 * For ioctls, there is no generic way to determine how much memory
1749 * needs to be read and/or written.  Furthermore, ioctls are allowed
1750 * to dereference the passed pointer, so the parameter requires deep
1751 * copying but FUSE has no idea whatsoever about what to copy in or
1752 * out.
1753 *
1754 * This is solved by allowing FUSE server to retry ioctl with
1755 * necessary in/out iovecs.  Let's assume the ioctl implementation
1756 * needs to read in the following structure.
1757 *
1758 * struct a {
1759 *	char	*buf;
1760 *	size_t	buflen;
1761 * }
1762 *
1763 * On the first callout to FUSE server, inarg->in_size and
1764 * inarg->out_size will be NULL; then, the server completes the ioctl
1765 * with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and
1766 * the actual iov array to
1767 *
1768 * { { .iov_base = inarg.arg,	.iov_len = sizeof(struct a) } }
1769 *
1770 * which tells FUSE to copy in the requested area and retry the ioctl.
1771 * On the second round, the server has access to the structure and
1772 * from that it can tell what to look for next, so on the invocation,
1773 * it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to
1774 *
1775 * { { .iov_base = inarg.arg,	.iov_len = sizeof(struct a)	},
1776 *   { .iov_base = a.buf,	.iov_len = a.buflen		} }
1777 *
1778 * FUSE will copy both struct a and the pointed buffer from the
1779 * process doing the ioctl and retry ioctl with both struct a and the
1780 * buffer.
1781 *
1782 * This time, FUSE server has everything it needs and completes ioctl
1783 * without FUSE_IOCTL_RETRY which finishes the ioctl call.
1784 *
1785 * Copying data out works the same way.
1786 *
1787 * Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel
1788 * automatically initializes in and out iovs by decoding @cmd with
1789 * _IOC_* macros and the server is not allowed to request RETRY.  This
1790 * limits ioctl data transfers to well-formed ioctls and is the forced
1791 * behavior for all FUSE servers.
1792 */
1793long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
1794		   unsigned int flags)
1795{
1796	struct fuse_file *ff = file->private_data;
1797	struct fuse_conn *fc = ff->fc;
1798	struct fuse_ioctl_in inarg = {
1799		.fh = ff->fh,
1800		.cmd = cmd,
1801		.arg = arg,
1802		.flags = flags
1803	};
1804	struct fuse_ioctl_out outarg;
1805	struct fuse_req *req = NULL;
1806	struct page **pages = NULL;
1807	struct iovec *iov_page = NULL;
1808	struct iovec *in_iov = NULL, *out_iov = NULL;
1809	unsigned int in_iovs = 0, out_iovs = 0, num_pages = 0, max_pages;
1810	size_t in_size, out_size, transferred;
1811	int err;
1812
1813#if BITS_PER_LONG == 32
1814	inarg.flags |= FUSE_IOCTL_32BIT;
1815#else
1816	if (flags & FUSE_IOCTL_COMPAT)
1817		inarg.flags |= FUSE_IOCTL_32BIT;
1818#endif
1819
1820	/* assume all the iovs returned by client always fits in a page */
1821	BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE);
1822
1823	err = -ENOMEM;
1824	pages = kcalloc(FUSE_MAX_PAGES_PER_REQ, sizeof(pages[0]), GFP_KERNEL);
1825	iov_page = (struct iovec *) __get_free_page(GFP_KERNEL);
1826	if (!pages || !iov_page)
1827		goto out;
1828
1829	/*
1830	 * If restricted, initialize IO parameters as encoded in @cmd.
1831	 * RETRY from server is not allowed.
1832	 */
1833	if (!(flags & FUSE_IOCTL_UNRESTRICTED)) {
1834		struct iovec *iov = iov_page;
1835
1836		iov->iov_base = (void __user *)arg;
1837		iov->iov_len = _IOC_SIZE(cmd);
1838
1839		if (_IOC_DIR(cmd) & _IOC_WRITE) {
1840			in_iov = iov;
1841			in_iovs = 1;
1842		}
1843
1844		if (_IOC_DIR(cmd) & _IOC_READ) {
1845			out_iov = iov;
1846			out_iovs = 1;
1847		}
1848	}
1849
1850 retry:
1851	inarg.in_size = in_size = iov_length(in_iov, in_iovs);
1852	inarg.out_size = out_size = iov_length(out_iov, out_iovs);
1853
1854	/*
1855	 * Out data can be used either for actual out data or iovs,
1856	 * make sure there always is at least one page.
1857	 */
1858	out_size = max_t(size_t, out_size, PAGE_SIZE);
1859	max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE);
1860
1861	/* make sure there are enough buffer pages and init request with them */
1862	err = -ENOMEM;
1863	if (max_pages > FUSE_MAX_PAGES_PER_REQ)
1864		goto out;
1865	while (num_pages < max_pages) {
1866		pages[num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
1867		if (!pages[num_pages])
1868			goto out;
1869		num_pages++;
1870	}
1871
1872	req = fuse_get_req(fc);
1873	if (IS_ERR(req)) {
1874		err = PTR_ERR(req);
1875		req = NULL;
1876		goto out;
1877	}
1878	memcpy(req->pages, pages, sizeof(req->pages[0]) * num_pages);
1879	req->num_pages = num_pages;
1880
1881	/* okay, let's send it to the client */
1882	req->in.h.opcode = FUSE_IOCTL;
1883	req->in.h.nodeid = ff->nodeid;
1884	req->in.numargs = 1;
1885	req->in.args[0].size = sizeof(inarg);
1886	req->in.args[0].value = &inarg;
1887	if (in_size) {
1888		req->in.numargs++;
1889		req->in.args[1].size = in_size;
1890		req->in.argpages = 1;
1891
1892		err = fuse_ioctl_copy_user(pages, in_iov, in_iovs, in_size,
1893					   false);
1894		if (err)
1895			goto out;
1896	}
1897
1898	req->out.numargs = 2;
1899	req->out.args[0].size = sizeof(outarg);
1900	req->out.args[0].value = &outarg;
1901	req->out.args[1].size = out_size;
1902	req->out.argpages = 1;
1903	req->out.argvar = 1;
1904
1905	fuse_request_send(fc, req);
1906	err = req->out.h.error;
1907	transferred = req->out.args[1].size;
1908	fuse_put_request(fc, req);
1909	req = NULL;
1910	if (err)
1911		goto out;
1912
1913	/* did it ask for retry? */
1914	if (outarg.flags & FUSE_IOCTL_RETRY) {
1915		void *vaddr;
1916
1917		/* no retry if in restricted mode */
1918		err = -EIO;
1919		if (!(flags & FUSE_IOCTL_UNRESTRICTED))
1920			goto out;
1921
1922		in_iovs = outarg.in_iovs;
1923		out_iovs = outarg.out_iovs;
1924
1925		/*
1926		 * Make sure things are in boundary, separate checks
1927		 * are to protect against overflow.
1928		 */
1929		err = -ENOMEM;
1930		if (in_iovs > FUSE_IOCTL_MAX_IOV ||
1931		    out_iovs > FUSE_IOCTL_MAX_IOV ||
1932		    in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV)
1933			goto out;
1934
1935		vaddr = kmap_atomic(pages[0]);
1936		err = fuse_copy_ioctl_iovec(fc, iov_page, vaddr,
1937					    transferred, in_iovs + out_iovs,
1938					    (flags & FUSE_IOCTL_COMPAT) != 0);
1939		kunmap_atomic(vaddr);
1940		if (err)
1941			goto out;
1942
1943		in_iov = iov_page;
1944		out_iov = in_iov + in_iovs;
1945
1946		err = fuse_verify_ioctl_iov(in_iov, in_iovs);
1947		if (err)
1948			goto out;
1949
1950		err = fuse_verify_ioctl_iov(out_iov, out_iovs);
1951		if (err)
1952			goto out;
1953
1954		goto retry;
1955	}
1956
1957	err = -EIO;
1958	if (transferred > inarg.out_size)
1959		goto out;
1960
1961	err = fuse_ioctl_copy_user(pages, out_iov, out_iovs, transferred, true);
1962 out:
1963	if (req)
1964		fuse_put_request(fc, req);
1965	free_page((unsigned long) iov_page);
1966	while (num_pages)
1967		__free_page(pages[--num_pages]);
1968	kfree(pages);
1969
1970	return err ? err : outarg.result;
1971}
1972EXPORT_SYMBOL_GPL(fuse_do_ioctl);
1973
1974long fuse_ioctl_common(struct file *file, unsigned int cmd,
1975		       unsigned long arg, unsigned int flags)
1976{
1977	struct inode *inode = file->f_dentry->d_inode;
1978	struct fuse_conn *fc = get_fuse_conn(inode);
1979
1980	if (!fuse_allow_task(fc, current))
1981		return -EACCES;
1982
1983	if (is_bad_inode(inode))
1984		return -EIO;
1985
1986	return fuse_do_ioctl(file, cmd, arg, flags);
1987}
1988
1989static long fuse_file_ioctl(struct file *file, unsigned int cmd,
1990			    unsigned long arg)
1991{
1992	return fuse_ioctl_common(file, cmd, arg, 0);
1993}
1994
1995static long fuse_file_compat_ioctl(struct file *file, unsigned int cmd,
1996				   unsigned long arg)
1997{
1998	return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT);
1999}
2000
2001/*
2002 * All files which have been polled are linked to RB tree
2003 * fuse_conn->polled_files which is indexed by kh.  Walk the tree and
2004 * find the matching one.
2005 */
2006static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
2007					      struct rb_node **parent_out)
2008{
2009	struct rb_node **link = &fc->polled_files.rb_node;
2010	struct rb_node *last = NULL;
2011
2012	while (*link) {
2013		struct fuse_file *ff;
2014
2015		last = *link;
2016		ff = rb_entry(last, struct fuse_file, polled_node);
2017
2018		if (kh < ff->kh)
2019			link = &last->rb_left;
2020		else if (kh > ff->kh)
2021			link = &last->rb_right;
2022		else
2023			return link;
2024	}
2025
2026	if (parent_out)
2027		*parent_out = last;
2028	return link;
2029}
2030
2031/*
2032 * The file is about to be polled.  Make sure it's on the polled_files
2033 * RB tree.  Note that files once added to the polled_files tree are
2034 * not removed before the file is released.  This is because a file
2035 * polled once is likely to be polled again.
2036 */
2037static void fuse_register_polled_file(struct fuse_conn *fc,
2038				      struct fuse_file *ff)
2039{
2040	spin_lock(&fc->lock);
2041	if (RB_EMPTY_NODE(&ff->polled_node)) {
2042		struct rb_node **link, *parent;
2043
2044		link = fuse_find_polled_node(fc, ff->kh, &parent);
2045		BUG_ON(*link);
2046		rb_link_node(&ff->polled_node, parent, link);
2047		rb_insert_color(&ff->polled_node, &fc->polled_files);
2048	}
2049	spin_unlock(&fc->lock);
2050}
2051
2052unsigned fuse_file_poll(struct file *file, poll_table *wait)
2053{
2054	struct fuse_file *ff = file->private_data;
2055	struct fuse_conn *fc = ff->fc;
2056	struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
2057	struct fuse_poll_out outarg;
2058	struct fuse_req *req;
2059	int err;
2060
2061	if (fc->no_poll)
2062		return DEFAULT_POLLMASK;
2063
2064	poll_wait(file, &ff->poll_wait, wait);
2065
2066	/*
2067	 * Ask for notification iff there's someone waiting for it.
2068	 * The client may ignore the flag and always notify.
2069	 */
2070	if (waitqueue_active(&ff->poll_wait)) {
2071		inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
2072		fuse_register_polled_file(fc, ff);
2073	}
2074
2075	req = fuse_get_req(fc);
2076	if (IS_ERR(req))
2077		return POLLERR;
2078
2079	req->in.h.opcode = FUSE_POLL;
2080	req->in.h.nodeid = ff->nodeid;
2081	req->in.numargs = 1;
2082	req->in.args[0].size = sizeof(inarg);
2083	req->in.args[0].value = &inarg;
2084	req->out.numargs = 1;
2085	req->out.args[0].size = sizeof(outarg);
2086	req->out.args[0].value = &outarg;
2087	fuse_request_send(fc, req);
2088	err = req->out.h.error;
2089	fuse_put_request(fc, req);
2090
2091	if (!err)
2092		return outarg.revents;
2093	if (err == -ENOSYS) {
2094		fc->no_poll = 1;
2095		return DEFAULT_POLLMASK;
2096	}
2097	return POLLERR;
2098}
2099EXPORT_SYMBOL_GPL(fuse_file_poll);
2100
2101/*
2102 * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
2103 * wakes up the poll waiters.
2104 */
2105int fuse_notify_poll_wakeup(struct fuse_conn *fc,
2106			    struct fuse_notify_poll_wakeup_out *outarg)
2107{
2108	u64 kh = outarg->kh;
2109	struct rb_node **link;
2110
2111	spin_lock(&fc->lock);
2112
2113	link = fuse_find_polled_node(fc, kh, NULL);
2114	if (*link) {
2115		struct fuse_file *ff;
2116
2117		ff = rb_entry(*link, struct fuse_file, polled_node);
2118		wake_up_interruptible_sync(&ff->poll_wait);
2119	}
2120
2121	spin_unlock(&fc->lock);
2122	return 0;
2123}
2124
2125static ssize_t fuse_loop_dio(struct file *filp, const struct iovec *iov,
2126			     unsigned long nr_segs, loff_t *ppos, int rw)
2127{
2128	const struct iovec *vector = iov;
2129	ssize_t ret = 0;
2130
2131	while (nr_segs > 0) {
2132		void __user *base;
2133		size_t len;
2134		ssize_t nr;
2135
2136		base = vector->iov_base;
2137		len = vector->iov_len;
2138		vector++;
2139		nr_segs--;
2140
2141		if (rw == WRITE)
2142			nr = __fuse_direct_write(filp, base, len, ppos);
2143		else
2144			nr = fuse_direct_read(filp, base, len, ppos);
2145
2146		if (nr < 0) {
2147			if (!ret)
2148				ret = nr;
2149			break;
2150		}
2151		ret += nr;
2152		if (nr != len)
2153			break;
2154	}
2155
2156	return ret;
2157}
2158
2159
2160static ssize_t
2161fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
2162			loff_t offset, unsigned long nr_segs)
2163{
2164	ssize_t ret = 0;
2165	struct file *file = NULL;
2166	loff_t pos = 0;
2167
2168	file = iocb->ki_filp;
2169	pos = offset;
2170
2171	ret = fuse_loop_dio(file, iov, nr_segs, &pos, rw);
2172
2173	return ret;
2174}
2175
2176long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
2177			    loff_t length)
2178{
2179	struct fuse_file *ff = file->private_data;
2180	struct fuse_conn *fc = ff->fc;
2181	struct fuse_req *req;
2182	struct fuse_fallocate_in inarg = {
2183		.fh = ff->fh,
2184		.offset = offset,
2185		.length = length,
2186		.mode = mode
2187	};
2188	int err;
2189
2190	if (fc->no_fallocate)
2191		return -EOPNOTSUPP;
2192
2193	req = fuse_get_req(fc);
2194	if (IS_ERR(req))
2195		return PTR_ERR(req);
2196
2197	req->in.h.opcode = FUSE_FALLOCATE;
2198	req->in.h.nodeid = ff->nodeid;
2199	req->in.numargs = 1;
2200	req->in.args[0].size = sizeof(inarg);
2201	req->in.args[0].value = &inarg;
2202	fuse_request_send(fc, req);
2203	err = req->out.h.error;
2204	if (err == -ENOSYS) {
2205		fc->no_fallocate = 1;
2206		err = -EOPNOTSUPP;
2207	}
2208	fuse_put_request(fc, req);
2209
2210	return err;
2211}
2212EXPORT_SYMBOL_GPL(fuse_file_fallocate);
2213
2214static const struct file_operations fuse_file_operations = {
2215	.llseek		= fuse_file_llseek,
2216	.read		= do_sync_read,
2217	.aio_read	= fuse_file_aio_read,
2218	.write		= do_sync_write,
2219	.aio_write	= fuse_file_aio_write,
2220	.mmap		= fuse_file_mmap,
2221	.open		= fuse_open,
2222	.flush		= fuse_flush,
2223	.release	= fuse_release,
2224	.fsync		= fuse_fsync,
2225	.lock		= fuse_file_lock,
2226	.flock		= fuse_file_flock,
2227	.splice_read	= generic_file_splice_read,
2228	.unlocked_ioctl	= fuse_file_ioctl,
2229	.compat_ioctl	= fuse_file_compat_ioctl,
2230	.poll		= fuse_file_poll,
2231	.fallocate	= fuse_file_fallocate,
2232};
2233
2234static const struct file_operations fuse_direct_io_file_operations = {
2235	.llseek		= fuse_file_llseek,
2236	.read		= fuse_direct_read,
2237	.write		= fuse_direct_write,
2238	.mmap		= fuse_direct_mmap,
2239	.open		= fuse_open,
2240	.flush		= fuse_flush,
2241	.release	= fuse_release,
2242	.fsync		= fuse_fsync,
2243	.lock		= fuse_file_lock,
2244	.flock		= fuse_file_flock,
2245	.unlocked_ioctl	= fuse_file_ioctl,
2246	.compat_ioctl	= fuse_file_compat_ioctl,
2247	.poll		= fuse_file_poll,
2248	.fallocate	= fuse_file_fallocate,
2249	/* no splice_read */
2250};
2251
2252static const struct address_space_operations fuse_file_aops  = {
2253	.readpage	= fuse_readpage,
2254	.writepage	= fuse_writepage,
2255	.launder_page	= fuse_launder_page,
2256	.readpages	= fuse_readpages,
2257	.set_page_dirty	= __set_page_dirty_nobuffers,
2258	.bmap		= fuse_bmap,
2259	.direct_IO	= fuse_direct_IO,
2260};
2261
2262void fuse_init_file_inode(struct inode *inode)
2263{
2264	inode->i_fop = &fuse_file_operations;
2265	inode->i_data.a_ops = &fuse_file_aops;
2266}