proc.c 18.9 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747
/*
 *  linux/fs/nfs/proc.c
 *
 *  Copyright (C) 1992, 1993, 1994  Rick Sladkey
 *
 *  OS-independent nfs remote procedure call functions
 *
 *  Tuned by Alan Cox <A.Cox@swansea.ac.uk> for >3K buffers
 *  so at last we can have decent(ish) throughput off a 
 *  Sun server.
 *
 *  Coding optimized and cleaned up by Florian La Roche.
 *  Note: Error returns are optimized for NFS_OK, which isn't translated via
 *  nfs_stat_to_errno(), but happens to be already the right return code.
 *
 *  Also, the code currently doesn't check the size of the packet, when
 *  it decodes the packet.
 *
 *  Feel free to fix it and mail me the diffs if it worries you.
 *
 *  Completely rewritten to support the new RPC call interface;
 *  rewrote and moved the entire XDR stuff to xdr.c
 *  --Olaf Kirch June 1996
 *
 *  The code below initializes all auto variables explicitly, otherwise
 *  it will fail to work as a module (gcc generates a memset call for an
 *  incomplete struct).
 */

#include <linux/types.h>
#include <linux/param.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/in.h>
#include <linux/pagemap.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfs.h>
#include <linux/nfs2.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_page.h>
#include <linux/lockd/bind.h>
#include <linux/freezer.h>
#include "internal.h"

#define NFSDBG_FACILITY		NFSDBG_PROC

/*
 * wrapper to handle the -EKEYEXPIRED error message. This should generally
 * only happen if using krb5 auth and a user's TGT expires. NFSv2 doesn't
 * support the NFSERR_JUKEBOX error code, but we handle this situation in the
 * same way that we handle that error with NFSv3.
 */
static int
nfs_rpc_wrapper(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
{
	int res;
	do {
		res = rpc_call_sync(clnt, msg, flags);
		if (res != -EKEYEXPIRED)
			break;
		freezable_schedule_timeout_killable(NFS_JUKEBOX_RETRY_TIME);
		res = -ERESTARTSYS;
	} while (!fatal_signal_pending(current));
	return res;
}

#define rpc_call_sync(clnt, msg, flags)	nfs_rpc_wrapper(clnt, msg, flags)

static int
nfs_async_handle_expired_key(struct rpc_task *task)
{
	if (task->tk_status != -EKEYEXPIRED)
		return 0;
	task->tk_status = 0;
	rpc_restart_call(task);
	rpc_delay(task, NFS_JUKEBOX_RETRY_TIME);
	return 1;
}

/*
 * Bare-bones access to getattr: this is for nfs_read_super.
 */
static int
nfs_proc_get_root(struct nfs_server *server, struct nfs_fh *fhandle,
		  struct nfs_fsinfo *info)
{
	struct nfs_fattr *fattr = info->fattr;
	struct nfs2_fsstat fsinfo;
	struct rpc_message msg = {
		.rpc_proc	= &nfs_procedures[NFSPROC_GETATTR],
		.rpc_argp	= fhandle,
		.rpc_resp	= fattr,
	};
	int status;

	dprintk("%s: call getattr\n", __func__);
	nfs_fattr_init(fattr);
	status = rpc_call_sync(server->client, &msg, 0);
	/* Retry with default authentication if different */
	if (status && server->nfs_client->cl_rpcclient != server->client)
		status = rpc_call_sync(server->nfs_client->cl_rpcclient, &msg, 0);
	dprintk("%s: reply getattr: %d\n", __func__, status);
	if (status)
		return status;
	dprintk("%s: call statfs\n", __func__);
	msg.rpc_proc = &nfs_procedures[NFSPROC_STATFS];
	msg.rpc_resp = &fsinfo;
	status = rpc_call_sync(server->client, &msg, 0);
	/* Retry with default authentication if different */
	if (status && server->nfs_client->cl_rpcclient != server->client)
		status = rpc_call_sync(server->nfs_client->cl_rpcclient, &msg, 0);
	dprintk("%s: reply statfs: %d\n", __func__, status);
	if (status)
		return status;
	info->rtmax  = NFS_MAXDATA;
	info->rtpref = fsinfo.tsize;
	info->rtmult = fsinfo.bsize;
	info->wtmax  = NFS_MAXDATA;
	info->wtpref = fsinfo.tsize;
	info->wtmult = fsinfo.bsize;
	info->dtpref = fsinfo.tsize;
	info->maxfilesize = 0x7FFFFFFF;
	info->lease_time = 0;
	return 0;
}

/*
 * One function for each procedure in the NFS protocol.
 */
static int
nfs_proc_getattr(struct nfs_server *server, struct nfs_fh *fhandle,
		struct nfs_fattr *fattr)
{
	struct rpc_message msg = {
		.rpc_proc	= &nfs_procedures[NFSPROC_GETATTR],
		.rpc_argp	= fhandle,
		.rpc_resp	= fattr,
	};
	int	status;

	dprintk("NFS call  getattr\n");
	nfs_fattr_init(fattr);
	status = rpc_call_sync(server->client, &msg, 0);
	dprintk("NFS reply getattr: %d\n", status);
	return status;
}

static int
nfs_proc_setattr(struct dentry *dentry, struct nfs_fattr *fattr,
		 struct iattr *sattr)
{
	struct inode *inode = dentry->d_inode;
	struct nfs_sattrargs	arg = { 
		.fh	= NFS_FH(inode),
		.sattr	= sattr
	};
	struct rpc_message msg = {
		.rpc_proc	= &nfs_procedures[NFSPROC_SETATTR],
		.rpc_argp	= &arg,
		.rpc_resp	= fattr,
	};
	int	status;

	/* Mask out the non-modebit related stuff from attr->ia_mode */
	sattr->ia_mode &= S_IALLUGO;

	dprintk("NFS call  setattr\n");
	if (sattr->ia_valid & ATTR_FILE)
		msg.rpc_cred = nfs_file_cred(sattr->ia_file);
	nfs_fattr_init(fattr);
	status = rpc_call_sync(NFS_CLIENT(inode), &msg, 0);
	if (status == 0)
		nfs_setattr_update_inode(inode, sattr);
	dprintk("NFS reply setattr: %d\n", status);
	return status;
}

static int
nfs_proc_lookup(struct rpc_clnt *clnt, struct inode *dir, struct qstr *name,
		struct nfs_fh *fhandle, struct nfs_fattr *fattr)
{
	struct nfs_diropargs	arg = {
		.fh		= NFS_FH(dir),
		.name		= name->name,
		.len		= name->len
	};
	struct nfs_diropok	res = {
		.fh		= fhandle,
		.fattr		= fattr
	};
	struct rpc_message msg = {
		.rpc_proc	= &nfs_procedures[NFSPROC_LOOKUP],
		.rpc_argp	= &arg,
		.rpc_resp	= &res,
	};
	int			status;

	dprintk("NFS call  lookup %s\n", name->name);
	nfs_fattr_init(fattr);
	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
	dprintk("NFS reply lookup: %d\n", status);
	return status;
}

static int nfs_proc_readlink(struct inode *inode, struct page *page,
		unsigned int pgbase, unsigned int pglen)
{
	struct nfs_readlinkargs	args = {
		.fh		= NFS_FH(inode),
		.pgbase		= pgbase,
		.pglen		= pglen,
		.pages		= &page
	};
	struct rpc_message msg = {
		.rpc_proc	= &nfs_procedures[NFSPROC_READLINK],
		.rpc_argp	= &args,
	};
	int			status;

	dprintk("NFS call  readlink\n");
	status = rpc_call_sync(NFS_CLIENT(inode), &msg, 0);
	dprintk("NFS reply readlink: %d\n", status);
	return status;
}

struct nfs_createdata {
	struct nfs_createargs arg;
	struct nfs_diropok res;
	struct nfs_fh fhandle;
	struct nfs_fattr fattr;
};

static struct nfs_createdata *nfs_alloc_createdata(struct inode *dir,
		struct dentry *dentry, struct iattr *sattr)
{
	struct nfs_createdata *data;

	data = kmalloc(sizeof(*data), GFP_KERNEL);

	if (data != NULL) {
		data->arg.fh = NFS_FH(dir);
		data->arg.name = dentry->d_name.name;
		data->arg.len = dentry->d_name.len;
		data->arg.sattr = sattr;
		nfs_fattr_init(&data->fattr);
		data->fhandle.size = 0;
		data->res.fh = &data->fhandle;
		data->res.fattr = &data->fattr;
	}
	return data;
};

static void nfs_free_createdata(const struct nfs_createdata *data)
{
	kfree(data);
}

static int
nfs_proc_create(struct inode *dir, struct dentry *dentry, struct iattr *sattr,
		int flags, struct nfs_open_context *ctx)
{
	struct nfs_createdata *data;
	struct rpc_message msg = {
		.rpc_proc	= &nfs_procedures[NFSPROC_CREATE],
	};
	int status = -ENOMEM;

	dprintk("NFS call  create %s\n", dentry->d_name.name);
	data = nfs_alloc_createdata(dir, dentry, sattr);
	if (data == NULL)
		goto out;
	msg.rpc_argp = &data->arg;
	msg.rpc_resp = &data->res;
	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
	nfs_mark_for_revalidate(dir);
	if (status == 0)
		status = nfs_instantiate(dentry, data->res.fh, data->res.fattr);
	nfs_free_createdata(data);
out:
	dprintk("NFS reply create: %d\n", status);
	return status;
}

/*
 * In NFSv2, mknod is grafted onto the create call.
 */
static int
nfs_proc_mknod(struct inode *dir, struct dentry *dentry, struct iattr *sattr,
	       dev_t rdev)
{
	struct nfs_createdata *data;
	struct rpc_message msg = {
		.rpc_proc	= &nfs_procedures[NFSPROC_CREATE],
	};
	umode_t mode;
	int status = -ENOMEM;

	dprintk("NFS call  mknod %s\n", dentry->d_name.name);

	mode = sattr->ia_mode;
	if (S_ISFIFO(mode)) {
		sattr->ia_mode = (mode & ~S_IFMT) | S_IFCHR;
		sattr->ia_valid &= ~ATTR_SIZE;
	} else if (S_ISCHR(mode) || S_ISBLK(mode)) {
		sattr->ia_valid |= ATTR_SIZE;
		sattr->ia_size = new_encode_dev(rdev);/* get out your barf bag */
	}

	data = nfs_alloc_createdata(dir, dentry, sattr);
	if (data == NULL)
		goto out;
	msg.rpc_argp = &data->arg;
	msg.rpc_resp = &data->res;

	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
	nfs_mark_for_revalidate(dir);

	if (status == -EINVAL && S_ISFIFO(mode)) {
		sattr->ia_mode = mode;
		nfs_fattr_init(data->res.fattr);
		status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
	}
	if (status == 0)
		status = nfs_instantiate(dentry, data->res.fh, data->res.fattr);
	nfs_free_createdata(data);
out:
	dprintk("NFS reply mknod: %d\n", status);
	return status;
}
  
static int
nfs_proc_remove(struct inode *dir, struct qstr *name)
{
	struct nfs_removeargs arg = {
		.fh = NFS_FH(dir),
		.name.len = name->len,
		.name.name = name->name,
	};
	struct rpc_message msg = { 
		.rpc_proc = &nfs_procedures[NFSPROC_REMOVE],
		.rpc_argp = &arg,
	};
	int			status;

	dprintk("NFS call  remove %s\n", name->name);
	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
	nfs_mark_for_revalidate(dir);

	dprintk("NFS reply remove: %d\n", status);
	return status;
}

static void
nfs_proc_unlink_setup(struct rpc_message *msg, struct inode *dir)
{
	msg->rpc_proc = &nfs_procedures[NFSPROC_REMOVE];
}

static int nfs_proc_unlink_done(struct rpc_task *task, struct inode *dir)
{
	if (nfs_async_handle_expired_key(task))
		return 0;
	nfs_mark_for_revalidate(dir);
	return 1;
}

static void
nfs_proc_rename_setup(struct rpc_message *msg, struct inode *dir)
{
	msg->rpc_proc = &nfs_procedures[NFSPROC_RENAME];
}

static int
nfs_proc_rename_done(struct rpc_task *task, struct inode *old_dir,
		     struct inode *new_dir)
{
	if (nfs_async_handle_expired_key(task))
		return 0;
	nfs_mark_for_revalidate(old_dir);
	nfs_mark_for_revalidate(new_dir);
	return 1;
}

static int
nfs_proc_rename(struct inode *old_dir, struct qstr *old_name,
		struct inode *new_dir, struct qstr *new_name)
{
	struct nfs_renameargs	arg = {
		.old_dir	= NFS_FH(old_dir),
		.old_name	= old_name,
		.new_dir	= NFS_FH(new_dir),
		.new_name	= new_name,
	};
	struct rpc_message msg = {
		.rpc_proc	= &nfs_procedures[NFSPROC_RENAME],
		.rpc_argp	= &arg,
	};
	int			status;

	dprintk("NFS call  rename %s -> %s\n", old_name->name, new_name->name);
	status = rpc_call_sync(NFS_CLIENT(old_dir), &msg, 0);
	nfs_mark_for_revalidate(old_dir);
	nfs_mark_for_revalidate(new_dir);
	dprintk("NFS reply rename: %d\n", status);
	return status;
}

static int
nfs_proc_link(struct inode *inode, struct inode *dir, struct qstr *name)
{
	struct nfs_linkargs	arg = {
		.fromfh		= NFS_FH(inode),
		.tofh		= NFS_FH(dir),
		.toname		= name->name,
		.tolen		= name->len
	};
	struct rpc_message msg = {
		.rpc_proc	= &nfs_procedures[NFSPROC_LINK],
		.rpc_argp	= &arg,
	};
	int			status;

	dprintk("NFS call  link %s\n", name->name);
	status = rpc_call_sync(NFS_CLIENT(inode), &msg, 0);
	nfs_mark_for_revalidate(inode);
	nfs_mark_for_revalidate(dir);
	dprintk("NFS reply link: %d\n", status);
	return status;
}

static int
nfs_proc_symlink(struct inode *dir, struct dentry *dentry, struct page *page,
		 unsigned int len, struct iattr *sattr)
{
	struct nfs_fh *fh;
	struct nfs_fattr *fattr;
	struct nfs_symlinkargs	arg = {
		.fromfh		= NFS_FH(dir),
		.fromname	= dentry->d_name.name,
		.fromlen	= dentry->d_name.len,
		.pages		= &page,
		.pathlen	= len,
		.sattr		= sattr
	};
	struct rpc_message msg = {
		.rpc_proc	= &nfs_procedures[NFSPROC_SYMLINK],
		.rpc_argp	= &arg,
	};
	int status = -ENAMETOOLONG;

	dprintk("NFS call  symlink %s\n", dentry->d_name.name);

	if (len > NFS2_MAXPATHLEN)
		goto out;

	fh = nfs_alloc_fhandle();
	fattr = nfs_alloc_fattr();
	status = -ENOMEM;
	if (fh == NULL || fattr == NULL)
		goto out_free;

	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
	nfs_mark_for_revalidate(dir);

	/*
	 * V2 SYMLINK requests don't return any attributes.  Setting the
	 * filehandle size to zero indicates to nfs_instantiate that it
	 * should fill in the data with a LOOKUP call on the wire.
	 */
	if (status == 0)
		status = nfs_instantiate(dentry, fh, fattr);

out_free:
	nfs_free_fattr(fattr);
	nfs_free_fhandle(fh);
out:
	dprintk("NFS reply symlink: %d\n", status);
	return status;
}

static int
nfs_proc_mkdir(struct inode *dir, struct dentry *dentry, struct iattr *sattr)
{
	struct nfs_createdata *data;
	struct rpc_message msg = {
		.rpc_proc	= &nfs_procedures[NFSPROC_MKDIR],
	};
	int status = -ENOMEM;

	dprintk("NFS call  mkdir %s\n", dentry->d_name.name);
	data = nfs_alloc_createdata(dir, dentry, sattr);
	if (data == NULL)
		goto out;
	msg.rpc_argp = &data->arg;
	msg.rpc_resp = &data->res;

	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
	nfs_mark_for_revalidate(dir);
	if (status == 0)
		status = nfs_instantiate(dentry, data->res.fh, data->res.fattr);
	nfs_free_createdata(data);
out:
	dprintk("NFS reply mkdir: %d\n", status);
	return status;
}

static int
nfs_proc_rmdir(struct inode *dir, struct qstr *name)
{
	struct nfs_diropargs	arg = {
		.fh		= NFS_FH(dir),
		.name		= name->name,
		.len		= name->len
	};
	struct rpc_message msg = {
		.rpc_proc	= &nfs_procedures[NFSPROC_RMDIR],
		.rpc_argp	= &arg,
	};
	int			status;

	dprintk("NFS call  rmdir %s\n", name->name);
	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
	nfs_mark_for_revalidate(dir);
	dprintk("NFS reply rmdir: %d\n", status);
	return status;
}

/*
 * The READDIR implementation is somewhat hackish - we pass a temporary
 * buffer to the encode function, which installs it in the receive
 * the receive iovec. The decode function just parses the reply to make
 * sure it is syntactically correct; the entries itself are decoded
 * from nfs_readdir by calling the decode_entry function directly.
 */
static int
nfs_proc_readdir(struct dentry *dentry, struct rpc_cred *cred,
		 u64 cookie, struct page **pages, unsigned int count, int plus)
{
	struct inode		*dir = dentry->d_inode;
	struct nfs_readdirargs	arg = {
		.fh		= NFS_FH(dir),
		.cookie		= cookie,
		.count		= count,
		.pages		= pages,
	};
	struct rpc_message	msg = {
		.rpc_proc	= &nfs_procedures[NFSPROC_READDIR],
		.rpc_argp	= &arg,
		.rpc_cred	= cred,
	};
	int			status;

	dprintk("NFS call  readdir %d\n", (unsigned int)cookie);
	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);

	nfs_invalidate_atime(dir);

	dprintk("NFS reply readdir: %d\n", status);
	return status;
}

static int
nfs_proc_statfs(struct nfs_server *server, struct nfs_fh *fhandle,
			struct nfs_fsstat *stat)
{
	struct nfs2_fsstat fsinfo;
	struct rpc_message msg = {
		.rpc_proc	= &nfs_procedures[NFSPROC_STATFS],
		.rpc_argp	= fhandle,
		.rpc_resp	= &fsinfo,
	};
	int	status;

	dprintk("NFS call  statfs\n");
	nfs_fattr_init(stat->fattr);
	status = rpc_call_sync(server->client, &msg, 0);
	dprintk("NFS reply statfs: %d\n", status);
	if (status)
		goto out;
	stat->tbytes = (u64)fsinfo.blocks * fsinfo.bsize;
	stat->fbytes = (u64)fsinfo.bfree  * fsinfo.bsize;
	stat->abytes = (u64)fsinfo.bavail * fsinfo.bsize;
	stat->tfiles = 0;
	stat->ffiles = 0;
	stat->afiles = 0;
out:
	return status;
}

static int
nfs_proc_fsinfo(struct nfs_server *server, struct nfs_fh *fhandle,
			struct nfs_fsinfo *info)
{
	struct nfs2_fsstat fsinfo;
	struct rpc_message msg = {
		.rpc_proc	= &nfs_procedures[NFSPROC_STATFS],
		.rpc_argp	= fhandle,
		.rpc_resp	= &fsinfo,
	};
	int	status;

	dprintk("NFS call  fsinfo\n");
	nfs_fattr_init(info->fattr);
	status = rpc_call_sync(server->client, &msg, 0);
	dprintk("NFS reply fsinfo: %d\n", status);
	if (status)
		goto out;
	info->rtmax  = NFS_MAXDATA;
	info->rtpref = fsinfo.tsize;
	info->rtmult = fsinfo.bsize;
	info->wtmax  = NFS_MAXDATA;
	info->wtpref = fsinfo.tsize;
	info->wtmult = fsinfo.bsize;
	info->dtpref = fsinfo.tsize;
	info->maxfilesize = 0x7FFFFFFF;
	info->lease_time = 0;
out:
	return status;
}

static int
nfs_proc_pathconf(struct nfs_server *server, struct nfs_fh *fhandle,
		  struct nfs_pathconf *info)
{
	info->max_link = 0;
	info->max_namelen = NFS2_MAXNAMLEN;
	return 0;
}

static int nfs_read_done(struct rpc_task *task, struct nfs_read_data *data)
{
	if (nfs_async_handle_expired_key(task))
		return -EAGAIN;

	nfs_invalidate_atime(data->inode);
	if (task->tk_status >= 0) {
		nfs_refresh_inode(data->inode, data->res.fattr);
		/* Emulate the eof flag, which isn't normally needed in NFSv2
		 * as it is guaranteed to always return the file attributes
		 */
		if (data->args.offset + data->args.count >= data->res.fattr->size)
			data->res.eof = 1;
	}
	return 0;
}

static void nfs_proc_read_setup(struct nfs_read_data *data, struct rpc_message *msg)
{
	msg->rpc_proc = &nfs_procedures[NFSPROC_READ];
}

static int nfs_write_done(struct rpc_task *task, struct nfs_write_data *data)
{
	if (nfs_async_handle_expired_key(task))
		return -EAGAIN;

	if (task->tk_status >= 0)
		nfs_post_op_update_inode_force_wcc(data->inode, data->res.fattr);
	return 0;
}

static void nfs_proc_write_setup(struct nfs_write_data *data, struct rpc_message *msg)
{
	/* Note: NFSv2 ignores @stable and always uses NFS_FILE_SYNC */
	data->args.stable = NFS_FILE_SYNC;
	msg->rpc_proc = &nfs_procedures[NFSPROC_WRITE];
}

static void
nfs_proc_commit_setup(struct nfs_write_data *data, struct rpc_message *msg)
{
	BUG();
}

static int
nfs_proc_lock(struct file *filp, int cmd, struct file_lock *fl)
{
	struct inode *inode = filp->f_path.dentry->d_inode;

	return nlmclnt_proc(NFS_SERVER(inode)->nlm_host, cmd, fl);
}

/* Helper functions for NFS lock bounds checking */
#define NFS_LOCK32_OFFSET_MAX ((__s32)0x7fffffffUL)
static int nfs_lock_check_bounds(const struct file_lock *fl)
{
	__s32 start, end;

	start = (__s32)fl->fl_start;
	if ((loff_t)start != fl->fl_start)
		goto out_einval;

	if (fl->fl_end != OFFSET_MAX) {
		end = (__s32)fl->fl_end;
		if ((loff_t)end != fl->fl_end)
			goto out_einval;
	} else
		end = NFS_LOCK32_OFFSET_MAX;

	if (start < 0 || start > end)
		goto out_einval;
	return 0;
out_einval:
	return -EINVAL;
}

const struct nfs_rpc_ops nfs_v2_clientops = {
	.version	= 2,		       /* protocol version */
	.dentry_ops	= &nfs_dentry_operations,
	.dir_inode_ops	= &nfs_dir_inode_operations,
	.file_inode_ops	= &nfs_file_inode_operations,
	.file_ops	= &nfs_file_operations,
	.getroot	= nfs_proc_get_root,
	.getattr	= nfs_proc_getattr,
	.setattr	= nfs_proc_setattr,
	.lookup		= nfs_proc_lookup,
	.access		= NULL,		       /* access */
	.readlink	= nfs_proc_readlink,
	.create		= nfs_proc_create,
	.remove		= nfs_proc_remove,
	.unlink_setup	= nfs_proc_unlink_setup,
	.unlink_done	= nfs_proc_unlink_done,
	.rename		= nfs_proc_rename,
	.rename_setup	= nfs_proc_rename_setup,
	.rename_done	= nfs_proc_rename_done,
	.link		= nfs_proc_link,
	.symlink	= nfs_proc_symlink,
	.mkdir		= nfs_proc_mkdir,
	.rmdir		= nfs_proc_rmdir,
	.readdir	= nfs_proc_readdir,
	.mknod		= nfs_proc_mknod,
	.statfs		= nfs_proc_statfs,
	.fsinfo		= nfs_proc_fsinfo,
	.pathconf	= nfs_proc_pathconf,
	.decode_dirent	= nfs2_decode_dirent,
	.read_setup	= nfs_proc_read_setup,
	.read_done	= nfs_read_done,
	.write_setup	= nfs_proc_write_setup,
	.write_done	= nfs_write_done,
	.commit_setup	= nfs_proc_commit_setup,
	.lock		= nfs_proc_lock,
	.lock_check_bounds = nfs_lock_check_bounds,
	.close_context	= nfs_close_context,
	.init_client	= nfs_init_client,
};