xref: /linux/net/9p/client.c (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9)
1 /*
2  * net/9p/clnt.c
3  *
4  * 9P Client
5  *
6  *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
7  *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
8  *
9  *  This program is free software; you can redistribute it and/or modify
10  *  it under the terms of the GNU General Public License version 2
11  *  as published by the Free Software Foundation.
12  *
13  *  This program is distributed in the hope that it will be useful,
14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  *  GNU General Public License for more details.
17  *
18  *  You should have received a copy of the GNU General Public License
19  *  along with this program; if not, write to:
20  *  Free Software Foundation
21  *  51 Franklin Street, Fifth Floor
22  *  Boston, MA  02111-1301  USA
23  *
24  */
25 
26 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27 
28 #include <linux/module.h>
29 #include <linux/errno.h>
30 #include <linux/fs.h>
31 #include <linux/poll.h>
32 #include <linux/idr.h>
33 #include <linux/mutex.h>
34 #include <linux/slab.h>
35 #include <linux/sched/signal.h>
36 #include <linux/uaccess.h>
37 #include <linux/uio.h>
38 #include <net/9p/9p.h>
39 #include <linux/parser.h>
40 #include <net/9p/client.h>
41 #include <net/9p/transport.h>
42 #include "protocol.h"
43 
44 #define CREATE_TRACE_POINTS
45 #include <trace/events/9p.h>
46 
47 /*
48   * Client Option Parsing (code inspired by NFS code)
49   *  - a little lazy - parse all client options
50   */
51 
52 enum {
53 	Opt_msize,
54 	Opt_trans,
55 	Opt_legacy,
56 	Opt_version,
57 	Opt_err,
58 };
59 
60 static const match_table_t tokens = {
61 	{Opt_msize, "msize=%u"},
62 	{Opt_legacy, "noextend"},
63 	{Opt_trans, "trans=%s"},
64 	{Opt_version, "version=%s"},
65 	{Opt_err, NULL},
66 };
67 
68 inline int p9_is_proto_dotl(struct p9_client *clnt)
69 {
70 	return clnt->proto_version == p9_proto_2000L;
71 }
72 EXPORT_SYMBOL(p9_is_proto_dotl);
73 
74 inline int p9_is_proto_dotu(struct p9_client *clnt)
75 {
76 	return clnt->proto_version == p9_proto_2000u;
77 }
78 EXPORT_SYMBOL(p9_is_proto_dotu);
79 
80 /*
81  * Some error codes are taken directly from the server replies,
82  * make sure they are valid.
83  */
84 static int safe_errno(int err)
85 {
86 	if ((err > 0) || (err < -MAX_ERRNO)) {
87 		p9_debug(P9_DEBUG_ERROR, "Invalid error code %d\n", err);
88 		return -EPROTO;
89 	}
90 	return err;
91 }
92 
93 
94 /* Interpret mount option for protocol version */
95 static int get_protocol_version(char *s)
96 {
97 	int version = -EINVAL;
98 
99 	if (!strcmp(s, "9p2000")) {
100 		version = p9_proto_legacy;
101 		p9_debug(P9_DEBUG_9P, "Protocol version: Legacy\n");
102 	} else if (!strcmp(s, "9p2000.u")) {
103 		version = p9_proto_2000u;
104 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.u\n");
105 	} else if (!strcmp(s, "9p2000.L")) {
106 		version = p9_proto_2000L;
107 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.L\n");
108 	} else
109 		pr_info("Unknown protocol version %s\n", s);
110 
111 	return version;
112 }
113 
114 /**
115  * parse_options - parse mount options into client structure
116  * @opts: options string passed from mount
117  * @clnt: existing v9fs client information
118  *
119  * Return 0 upon success, -ERRNO upon failure
120  */
121 
122 static int parse_opts(char *opts, struct p9_client *clnt)
123 {
124 	char *options, *tmp_options;
125 	char *p;
126 	substring_t args[MAX_OPT_ARGS];
127 	int option;
128 	char *s;
129 	int ret = 0;
130 
131 	clnt->proto_version = p9_proto_2000L;
132 	clnt->msize = 8192;
133 
134 	if (!opts)
135 		return 0;
136 
137 	tmp_options = kstrdup(opts, GFP_KERNEL);
138 	if (!tmp_options) {
139 		p9_debug(P9_DEBUG_ERROR,
140 			 "failed to allocate copy of option string\n");
141 		return -ENOMEM;
142 	}
143 	options = tmp_options;
144 
145 	while ((p = strsep(&options, ",")) != NULL) {
146 		int token, r;
147 		if (!*p)
148 			continue;
149 		token = match_token(p, tokens, args);
150 		switch (token) {
151 		case Opt_msize:
152 			r = match_int(&args[0], &option);
153 			if (r < 0) {
154 				p9_debug(P9_DEBUG_ERROR,
155 					 "integer field, but no integer?\n");
156 				ret = r;
157 				continue;
158 			}
159 			clnt->msize = option;
160 			break;
161 		case Opt_trans:
162 			s = match_strdup(&args[0]);
163 			if (!s) {
164 				ret = -ENOMEM;
165 				p9_debug(P9_DEBUG_ERROR,
166 					 "problem allocating copy of trans arg\n");
167 				goto free_and_return;
168 			 }
169 			clnt->trans_mod = v9fs_get_trans_by_name(s);
170 			if (clnt->trans_mod == NULL) {
171 				pr_info("Could not find request transport: %s\n",
172 					s);
173 				ret = -EINVAL;
174 				kfree(s);
175 				goto free_and_return;
176 			}
177 			kfree(s);
178 			break;
179 		case Opt_legacy:
180 			clnt->proto_version = p9_proto_legacy;
181 			break;
182 		case Opt_version:
183 			s = match_strdup(&args[0]);
184 			if (!s) {
185 				ret = -ENOMEM;
186 				p9_debug(P9_DEBUG_ERROR,
187 					 "problem allocating copy of version arg\n");
188 				goto free_and_return;
189 			}
190 			ret = get_protocol_version(s);
191 			if (ret == -EINVAL) {
192 				kfree(s);
193 				goto free_and_return;
194 			}
195 			kfree(s);
196 			clnt->proto_version = ret;
197 			break;
198 		default:
199 			continue;
200 		}
201 	}
202 
203 free_and_return:
204 	kfree(tmp_options);
205 	return ret;
206 }
207 
208 static struct p9_fcall *p9_fcall_alloc(int alloc_msize)
209 {
210 	struct p9_fcall *fc;
211 	fc = kmalloc(sizeof(struct p9_fcall) + alloc_msize, GFP_NOFS);
212 	if (!fc)
213 		return NULL;
214 	fc->capacity = alloc_msize;
215 	fc->sdata = (char *) fc + sizeof(struct p9_fcall);
216 	return fc;
217 }
218 
219 /**
220  * p9_tag_alloc - lookup/allocate a request by tag
221  * @c: client session to lookup tag within
222  * @tag: numeric id for transaction
223  *
224  * this is a simple array lookup, but will grow the
225  * request_slots as necessary to accommodate transaction
226  * ids which did not previously have a slot.
227  *
228  * this code relies on the client spinlock to manage locks, its
229  * possible we should switch to something else, but I'd rather
230  * stick with something low-overhead for the common case.
231  *
232  */
233 
234 static struct p9_req_t *
235 p9_tag_alloc(struct p9_client *c, u16 tag, unsigned int max_size)
236 {
237 	unsigned long flags;
238 	int row, col;
239 	struct p9_req_t *req;
240 	int alloc_msize = min(c->msize, max_size);
241 
242 	/* This looks up the original request by tag so we know which
243 	 * buffer to read the data into */
244 	tag++;
245 
246 	if (tag >= c->max_tag) {
247 		spin_lock_irqsave(&c->lock, flags);
248 		/* check again since original check was outside of lock */
249 		while (tag >= c->max_tag) {
250 			row = (tag / P9_ROW_MAXTAG);
251 			c->reqs[row] = kcalloc(P9_ROW_MAXTAG,
252 					sizeof(struct p9_req_t), GFP_ATOMIC);
253 
254 			if (!c->reqs[row]) {
255 				pr_err("Couldn't grow tag array\n");
256 				spin_unlock_irqrestore(&c->lock, flags);
257 				return ERR_PTR(-ENOMEM);
258 			}
259 			for (col = 0; col < P9_ROW_MAXTAG; col++) {
260 				c->reqs[row][col].status = REQ_STATUS_IDLE;
261 				c->reqs[row][col].tc = NULL;
262 			}
263 			c->max_tag += P9_ROW_MAXTAG;
264 		}
265 		spin_unlock_irqrestore(&c->lock, flags);
266 	}
267 	row = tag / P9_ROW_MAXTAG;
268 	col = tag % P9_ROW_MAXTAG;
269 
270 	req = &c->reqs[row][col];
271 	if (!req->wq) {
272 		req->wq = kmalloc(sizeof(wait_queue_head_t), GFP_NOFS);
273 		if (!req->wq)
274 			goto grow_failed;
275 		init_waitqueue_head(req->wq);
276 	}
277 
278 	if (!req->tc)
279 		req->tc = p9_fcall_alloc(alloc_msize);
280 	if (!req->rc)
281 		req->rc = p9_fcall_alloc(alloc_msize);
282 	if (!req->tc || !req->rc)
283 		goto grow_failed;
284 
285 	p9pdu_reset(req->tc);
286 	p9pdu_reset(req->rc);
287 
288 	req->tc->tag = tag-1;
289 	req->status = REQ_STATUS_ALLOC;
290 
291 	return req;
292 
293 grow_failed:
294 	pr_err("Couldn't grow tag array\n");
295 	kfree(req->tc);
296 	kfree(req->rc);
297 	kfree(req->wq);
298 	req->tc = req->rc = NULL;
299 	req->wq = NULL;
300 	return ERR_PTR(-ENOMEM);
301 }
302 
303 /**
304  * p9_tag_lookup - lookup a request by tag
305  * @c: client session to lookup tag within
306  * @tag: numeric id for transaction
307  *
308  */
309 
310 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
311 {
312 	int row, col;
313 
314 	/* This looks up the original request by tag so we know which
315 	 * buffer to read the data into */
316 	tag++;
317 
318 	if(tag >= c->max_tag)
319 		return NULL;
320 
321 	row = tag / P9_ROW_MAXTAG;
322 	col = tag % P9_ROW_MAXTAG;
323 
324 	return &c->reqs[row][col];
325 }
326 EXPORT_SYMBOL(p9_tag_lookup);
327 
328 /**
329  * p9_tag_init - setup tags structure and contents
330  * @c:  v9fs client struct
331  *
332  * This initializes the tags structure for each client instance.
333  *
334  */
335 
336 static int p9_tag_init(struct p9_client *c)
337 {
338 	int err = 0;
339 
340 	c->tagpool = p9_idpool_create();
341 	if (IS_ERR(c->tagpool)) {
342 		err = PTR_ERR(c->tagpool);
343 		goto error;
344 	}
345 	err = p9_idpool_get(c->tagpool); /* reserve tag 0 */
346 	if (err < 0) {
347 		p9_idpool_destroy(c->tagpool);
348 		goto error;
349 	}
350 	c->max_tag = 0;
351 error:
352 	return err;
353 }
354 
355 /**
356  * p9_tag_cleanup - cleans up tags structure and reclaims resources
357  * @c:  v9fs client struct
358  *
359  * This frees resources associated with the tags structure
360  *
361  */
362 static void p9_tag_cleanup(struct p9_client *c)
363 {
364 	int row, col;
365 
366 	/* check to insure all requests are idle */
367 	for (row = 0; row < (c->max_tag/P9_ROW_MAXTAG); row++) {
368 		for (col = 0; col < P9_ROW_MAXTAG; col++) {
369 			if (c->reqs[row][col].status != REQ_STATUS_IDLE) {
370 				p9_debug(P9_DEBUG_MUX,
371 					 "Attempting to cleanup non-free tag %d,%d\n",
372 					 row, col);
373 				/* TODO: delay execution of cleanup */
374 				return;
375 			}
376 		}
377 	}
378 
379 	if (c->tagpool) {
380 		p9_idpool_put(0, c->tagpool); /* free reserved tag 0 */
381 		p9_idpool_destroy(c->tagpool);
382 	}
383 
384 	/* free requests associated with tags */
385 	for (row = 0; row < (c->max_tag/P9_ROW_MAXTAG); row++) {
386 		for (col = 0; col < P9_ROW_MAXTAG; col++) {
387 			kfree(c->reqs[row][col].wq);
388 			kfree(c->reqs[row][col].tc);
389 			kfree(c->reqs[row][col].rc);
390 		}
391 		kfree(c->reqs[row]);
392 	}
393 	c->max_tag = 0;
394 }
395 
396 /**
397  * p9_free_req - free a request and clean-up as necessary
398  * c: client state
399  * r: request to release
400  *
401  */
402 
403 static void p9_free_req(struct p9_client *c, struct p9_req_t *r)
404 {
405 	int tag = r->tc->tag;
406 	p9_debug(P9_DEBUG_MUX, "clnt %p req %p tag: %d\n", c, r, tag);
407 
408 	r->status = REQ_STATUS_IDLE;
409 	if (tag != P9_NOTAG && p9_idpool_check(tag, c->tagpool))
410 		p9_idpool_put(tag, c->tagpool);
411 }
412 
413 /**
414  * p9_client_cb - call back from transport to client
415  * c: client state
416  * req: request received
417  *
418  */
419 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
420 {
421 	p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc->tag);
422 
423 	/*
424 	 * This barrier is needed to make sure any change made to req before
425 	 * the other thread wakes up will indeed be seen by the waiting side.
426 	 */
427 	smp_wmb();
428 	req->status = status;
429 
430 	wake_up(req->wq);
431 	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc->tag);
432 }
433 EXPORT_SYMBOL(p9_client_cb);
434 
435 /**
436  * p9_parse_header - parse header arguments out of a packet
437  * @pdu: packet to parse
438  * @size: size of packet
439  * @type: type of request
440  * @tag: tag of packet
441  * @rewind: set if we need to rewind offset afterwards
442  */
443 
444 int
445 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type, int16_t *tag,
446 								int rewind)
447 {
448 	int8_t r_type;
449 	int16_t r_tag;
450 	int32_t r_size;
451 	int offset = pdu->offset;
452 	int err;
453 
454 	pdu->offset = 0;
455 	if (pdu->size == 0)
456 		pdu->size = 7;
457 
458 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
459 	if (err)
460 		goto rewind_and_exit;
461 
462 	pdu->size = r_size;
463 	pdu->id = r_type;
464 	pdu->tag = r_tag;
465 
466 	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
467 		 pdu->size, pdu->id, pdu->tag);
468 
469 	if (type)
470 		*type = r_type;
471 	if (tag)
472 		*tag = r_tag;
473 	if (size)
474 		*size = r_size;
475 
476 
477 rewind_and_exit:
478 	if (rewind)
479 		pdu->offset = offset;
480 	return err;
481 }
482 EXPORT_SYMBOL(p9_parse_header);
483 
484 /**
485  * p9_check_errors - check 9p packet for error return and process it
486  * @c: current client instance
487  * @req: request to parse and check for error conditions
488  *
489  * returns error code if one is discovered, otherwise returns 0
490  *
491  * this will have to be more complicated if we have multiple
492  * error packet types
493  */
494 
495 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
496 {
497 	int8_t type;
498 	int err;
499 	int ecode;
500 
501 	err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
502 	/*
503 	 * dump the response from server
504 	 * This should be after check errors which poplulate pdu_fcall.
505 	 */
506 	trace_9p_protocol_dump(c, req->rc);
507 	if (err) {
508 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
509 		return err;
510 	}
511 	if (type != P9_RERROR && type != P9_RLERROR)
512 		return 0;
513 
514 	if (!p9_is_proto_dotl(c)) {
515 		char *ename;
516 		err = p9pdu_readf(req->rc, c->proto_version, "s?d",
517 				  &ename, &ecode);
518 		if (err)
519 			goto out_err;
520 
521 		if (p9_is_proto_dotu(c) && ecode < 512)
522 			err = -ecode;
523 
524 		if (!err) {
525 			err = p9_errstr2errno(ename, strlen(ename));
526 
527 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
528 				 -ecode, ename);
529 		}
530 		kfree(ename);
531 	} else {
532 		err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode);
533 		err = -ecode;
534 
535 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
536 	}
537 
538 	return err;
539 
540 out_err:
541 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
542 
543 	return err;
544 }
545 
546 /**
547  * p9_check_zc_errors - check 9p packet for error return and process it
548  * @c: current client instance
549  * @req: request to parse and check for error conditions
550  * @in_hdrlen: Size of response protocol buffer.
551  *
552  * returns error code if one is discovered, otherwise returns 0
553  *
554  * this will have to be more complicated if we have multiple
555  * error packet types
556  */
557 
558 static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
559 			      struct iov_iter *uidata, int in_hdrlen)
560 {
561 	int err;
562 	int ecode;
563 	int8_t type;
564 	char *ename = NULL;
565 
566 	err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
567 	/*
568 	 * dump the response from server
569 	 * This should be after parse_header which poplulate pdu_fcall.
570 	 */
571 	trace_9p_protocol_dump(c, req->rc);
572 	if (err) {
573 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
574 		return err;
575 	}
576 
577 	if (type != P9_RERROR && type != P9_RLERROR)
578 		return 0;
579 
580 	if (!p9_is_proto_dotl(c)) {
581 		/* Error is reported in string format */
582 		int len;
583 		/* 7 = header size for RERROR; */
584 		int inline_len = in_hdrlen - 7;
585 
586 		len =  req->rc->size - req->rc->offset;
587 		if (len > (P9_ZC_HDR_SZ - 7)) {
588 			err = -EFAULT;
589 			goto out_err;
590 		}
591 
592 		ename = &req->rc->sdata[req->rc->offset];
593 		if (len > inline_len) {
594 			/* We have error in external buffer */
595 			err = copy_from_iter(ename + inline_len,
596 					     len - inline_len, uidata);
597 			if (err != len - inline_len) {
598 				err = -EFAULT;
599 				goto out_err;
600 			}
601 		}
602 		ename = NULL;
603 		err = p9pdu_readf(req->rc, c->proto_version, "s?d",
604 				  &ename, &ecode);
605 		if (err)
606 			goto out_err;
607 
608 		if (p9_is_proto_dotu(c) && ecode < 512)
609 			err = -ecode;
610 
611 		if (!err) {
612 			err = p9_errstr2errno(ename, strlen(ename));
613 
614 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
615 				 -ecode, ename);
616 		}
617 		kfree(ename);
618 	} else {
619 		err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode);
620 		err = -ecode;
621 
622 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
623 	}
624 	return err;
625 
626 out_err:
627 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
628 	return err;
629 }
630 
631 static struct p9_req_t *
632 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
633 
634 /**
635  * p9_client_flush - flush (cancel) a request
636  * @c: client state
637  * @oldreq: request to cancel
638  *
639  * This sents a flush for a particular request and links
640  * the flush request to the original request.  The current
641  * code only supports a single flush request although the protocol
642  * allows for multiple flush requests to be sent for a single request.
643  *
644  */
645 
646 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
647 {
648 	struct p9_req_t *req;
649 	int16_t oldtag;
650 	int err;
651 
652 	err = p9_parse_header(oldreq->tc, NULL, NULL, &oldtag, 1);
653 	if (err)
654 		return err;
655 
656 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
657 
658 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
659 	if (IS_ERR(req))
660 		return PTR_ERR(req);
661 
662 	/*
663 	 * if we haven't received a response for oldreq,
664 	 * remove it from the list
665 	 */
666 	if (oldreq->status == REQ_STATUS_SENT)
667 		if (c->trans_mod->cancelled)
668 			c->trans_mod->cancelled(c, oldreq);
669 
670 	p9_free_req(c, req);
671 	return 0;
672 }
673 
674 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
675 					      int8_t type, int req_size,
676 					      const char *fmt, va_list ap)
677 {
678 	int tag, err;
679 	struct p9_req_t *req;
680 
681 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
682 
683 	/* we allow for any status other than disconnected */
684 	if (c->status == Disconnected)
685 		return ERR_PTR(-EIO);
686 
687 	/* if status is begin_disconnected we allow only clunk request */
688 	if ((c->status == BeginDisconnect) && (type != P9_TCLUNK))
689 		return ERR_PTR(-EIO);
690 
691 	tag = P9_NOTAG;
692 	if (type != P9_TVERSION) {
693 		tag = p9_idpool_get(c->tagpool);
694 		if (tag < 0)
695 			return ERR_PTR(-ENOMEM);
696 	}
697 
698 	req = p9_tag_alloc(c, tag, req_size);
699 	if (IS_ERR(req))
700 		return req;
701 
702 	/* marshall the data */
703 	p9pdu_prepare(req->tc, tag, type);
704 	err = p9pdu_vwritef(req->tc, c->proto_version, fmt, ap);
705 	if (err)
706 		goto reterr;
707 	p9pdu_finalize(c, req->tc);
708 	trace_9p_client_req(c, type, tag);
709 	return req;
710 reterr:
711 	p9_free_req(c, req);
712 	return ERR_PTR(err);
713 }
714 
715 /**
716  * p9_client_rpc - issue a request and wait for a response
717  * @c: client session
718  * @type: type of request
719  * @fmt: protocol format string (see protocol.c)
720  *
721  * Returns request structure (which client must free using p9_free_req)
722  */
723 
724 static struct p9_req_t *
725 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
726 {
727 	va_list ap;
728 	int sigpending, err;
729 	unsigned long flags;
730 	struct p9_req_t *req;
731 
732 	va_start(ap, fmt);
733 	req = p9_client_prepare_req(c, type, c->msize, fmt, ap);
734 	va_end(ap);
735 	if (IS_ERR(req))
736 		return req;
737 
738 	if (signal_pending(current)) {
739 		sigpending = 1;
740 		clear_thread_flag(TIF_SIGPENDING);
741 	} else
742 		sigpending = 0;
743 
744 	err = c->trans_mod->request(c, req);
745 	if (err < 0) {
746 		if (err != -ERESTARTSYS && err != -EFAULT)
747 			c->status = Disconnected;
748 		goto reterr;
749 	}
750 again:
751 	/* Wait for the response */
752 	err = wait_event_interruptible(*req->wq,
753 				       req->status >= REQ_STATUS_RCVD);
754 
755 	/*
756 	 * Make sure our req is coherent with regard to updates in other
757 	 * threads - echoes to wmb() in the callback
758 	 */
759 	smp_rmb();
760 
761 	if ((err == -ERESTARTSYS) && (c->status == Connected)
762 				  && (type == P9_TFLUSH)) {
763 		sigpending = 1;
764 		clear_thread_flag(TIF_SIGPENDING);
765 		goto again;
766 	}
767 
768 	if (req->status == REQ_STATUS_ERROR) {
769 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
770 		err = req->t_err;
771 	}
772 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
773 		p9_debug(P9_DEBUG_MUX, "flushing\n");
774 		sigpending = 1;
775 		clear_thread_flag(TIF_SIGPENDING);
776 
777 		if (c->trans_mod->cancel(c, req))
778 			p9_client_flush(c, req);
779 
780 		/* if we received the response anyway, don't signal error */
781 		if (req->status == REQ_STATUS_RCVD)
782 			err = 0;
783 	}
784 	if (sigpending) {
785 		spin_lock_irqsave(&current->sighand->siglock, flags);
786 		recalc_sigpending();
787 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
788 	}
789 	if (err < 0)
790 		goto reterr;
791 
792 	err = p9_check_errors(c, req);
793 	trace_9p_client_res(c, type, req->rc->tag, err);
794 	if (!err)
795 		return req;
796 reterr:
797 	p9_free_req(c, req);
798 	return ERR_PTR(safe_errno(err));
799 }
800 
801 /**
802  * p9_client_zc_rpc - issue a request and wait for a response
803  * @c: client session
804  * @type: type of request
805  * @uidata: destination for zero copy read
806  * @uodata: source for zero copy write
807  * @inlen: read buffer size
808  * @olen: write buffer size
809  * @hdrlen: reader header size, This is the size of response protocol data
810  * @fmt: protocol format string (see protocol.c)
811  *
812  * Returns request structure (which client must free using p9_free_req)
813  */
814 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
815 					 struct iov_iter *uidata,
816 					 struct iov_iter *uodata,
817 					 int inlen, int olen, int in_hdrlen,
818 					 const char *fmt, ...)
819 {
820 	va_list ap;
821 	int sigpending, err;
822 	unsigned long flags;
823 	struct p9_req_t *req;
824 
825 	va_start(ap, fmt);
826 	/*
827 	 * We allocate a inline protocol data of only 4k bytes.
828 	 * The actual content is passed in zero-copy fashion.
829 	 */
830 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, fmt, ap);
831 	va_end(ap);
832 	if (IS_ERR(req))
833 		return req;
834 
835 	if (signal_pending(current)) {
836 		sigpending = 1;
837 		clear_thread_flag(TIF_SIGPENDING);
838 	} else
839 		sigpending = 0;
840 
841 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
842 				       inlen, olen, in_hdrlen);
843 	if (err < 0) {
844 		if (err == -EIO)
845 			c->status = Disconnected;
846 		if (err != -ERESTARTSYS)
847 			goto reterr;
848 	}
849 	if (req->status == REQ_STATUS_ERROR) {
850 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
851 		err = req->t_err;
852 	}
853 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
854 		p9_debug(P9_DEBUG_MUX, "flushing\n");
855 		sigpending = 1;
856 		clear_thread_flag(TIF_SIGPENDING);
857 
858 		if (c->trans_mod->cancel(c, req))
859 			p9_client_flush(c, req);
860 
861 		/* if we received the response anyway, don't signal error */
862 		if (req->status == REQ_STATUS_RCVD)
863 			err = 0;
864 	}
865 	if (sigpending) {
866 		spin_lock_irqsave(&current->sighand->siglock, flags);
867 		recalc_sigpending();
868 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
869 	}
870 	if (err < 0)
871 		goto reterr;
872 
873 	err = p9_check_zc_errors(c, req, uidata, in_hdrlen);
874 	trace_9p_client_res(c, type, req->rc->tag, err);
875 	if (!err)
876 		return req;
877 reterr:
878 	p9_free_req(c, req);
879 	return ERR_PTR(safe_errno(err));
880 }
881 
882 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
883 {
884 	int ret;
885 	struct p9_fid *fid;
886 	unsigned long flags;
887 
888 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
889 	fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
890 	if (!fid)
891 		return ERR_PTR(-ENOMEM);
892 
893 	ret = p9_idpool_get(clnt->fidpool);
894 	if (ret < 0) {
895 		ret = -ENOSPC;
896 		goto error;
897 	}
898 	fid->fid = ret;
899 
900 	memset(&fid->qid, 0, sizeof(struct p9_qid));
901 	fid->mode = -1;
902 	fid->uid = current_fsuid();
903 	fid->clnt = clnt;
904 	fid->rdir = NULL;
905 	spin_lock_irqsave(&clnt->lock, flags);
906 	list_add(&fid->flist, &clnt->fidlist);
907 	spin_unlock_irqrestore(&clnt->lock, flags);
908 
909 	return fid;
910 
911 error:
912 	kfree(fid);
913 	return ERR_PTR(ret);
914 }
915 
916 static void p9_fid_destroy(struct p9_fid *fid)
917 {
918 	struct p9_client *clnt;
919 	unsigned long flags;
920 
921 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
922 	clnt = fid->clnt;
923 	p9_idpool_put(fid->fid, clnt->fidpool);
924 	spin_lock_irqsave(&clnt->lock, flags);
925 	list_del(&fid->flist);
926 	spin_unlock_irqrestore(&clnt->lock, flags);
927 	kfree(fid->rdir);
928 	kfree(fid);
929 }
930 
931 static int p9_client_version(struct p9_client *c)
932 {
933 	int err = 0;
934 	struct p9_req_t *req;
935 	char *version;
936 	int msize;
937 
938 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
939 		 c->msize, c->proto_version);
940 
941 	switch (c->proto_version) {
942 	case p9_proto_2000L:
943 		req = p9_client_rpc(c, P9_TVERSION, "ds",
944 					c->msize, "9P2000.L");
945 		break;
946 	case p9_proto_2000u:
947 		req = p9_client_rpc(c, P9_TVERSION, "ds",
948 					c->msize, "9P2000.u");
949 		break;
950 	case p9_proto_legacy:
951 		req = p9_client_rpc(c, P9_TVERSION, "ds",
952 					c->msize, "9P2000");
953 		break;
954 	default:
955 		return -EINVAL;
956 	}
957 
958 	if (IS_ERR(req))
959 		return PTR_ERR(req);
960 
961 	err = p9pdu_readf(req->rc, c->proto_version, "ds", &msize, &version);
962 	if (err) {
963 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
964 		trace_9p_protocol_dump(c, req->rc);
965 		goto error;
966 	}
967 
968 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
969 	if (!strncmp(version, "9P2000.L", 8))
970 		c->proto_version = p9_proto_2000L;
971 	else if (!strncmp(version, "9P2000.u", 8))
972 		c->proto_version = p9_proto_2000u;
973 	else if (!strncmp(version, "9P2000", 6))
974 		c->proto_version = p9_proto_legacy;
975 	else {
976 		err = -EREMOTEIO;
977 		goto error;
978 	}
979 
980 	if (msize < c->msize)
981 		c->msize = msize;
982 
983 error:
984 	kfree(version);
985 	p9_free_req(c, req);
986 
987 	return err;
988 }
989 
990 struct p9_client *p9_client_create(const char *dev_name, char *options)
991 {
992 	int err;
993 	struct p9_client *clnt;
994 	char *client_id;
995 
996 	err = 0;
997 	clnt = kmalloc(sizeof(struct p9_client), GFP_KERNEL);
998 	if (!clnt)
999 		return ERR_PTR(-ENOMEM);
1000 
1001 	clnt->trans_mod = NULL;
1002 	clnt->trans = NULL;
1003 
1004 	client_id = utsname()->nodename;
1005 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
1006 
1007 	spin_lock_init(&clnt->lock);
1008 	INIT_LIST_HEAD(&clnt->fidlist);
1009 
1010 	err = p9_tag_init(clnt);
1011 	if (err < 0)
1012 		goto free_client;
1013 
1014 	err = parse_opts(options, clnt);
1015 	if (err < 0)
1016 		goto destroy_tagpool;
1017 
1018 	if (!clnt->trans_mod)
1019 		clnt->trans_mod = v9fs_get_default_trans();
1020 
1021 	if (clnt->trans_mod == NULL) {
1022 		err = -EPROTONOSUPPORT;
1023 		p9_debug(P9_DEBUG_ERROR,
1024 			 "No transport defined or default transport\n");
1025 		goto destroy_tagpool;
1026 	}
1027 
1028 	clnt->fidpool = p9_idpool_create();
1029 	if (IS_ERR(clnt->fidpool)) {
1030 		err = PTR_ERR(clnt->fidpool);
1031 		goto put_trans;
1032 	}
1033 
1034 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
1035 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
1036 
1037 	err = clnt->trans_mod->create(clnt, dev_name, options);
1038 	if (err)
1039 		goto destroy_fidpool;
1040 
1041 	if (clnt->msize > clnt->trans_mod->maxsize)
1042 		clnt->msize = clnt->trans_mod->maxsize;
1043 
1044 	err = p9_client_version(clnt);
1045 	if (err)
1046 		goto close_trans;
1047 
1048 	return clnt;
1049 
1050 close_trans:
1051 	clnt->trans_mod->close(clnt);
1052 destroy_fidpool:
1053 	p9_idpool_destroy(clnt->fidpool);
1054 put_trans:
1055 	v9fs_put_trans(clnt->trans_mod);
1056 destroy_tagpool:
1057 	p9_idpool_destroy(clnt->tagpool);
1058 free_client:
1059 	kfree(clnt);
1060 	return ERR_PTR(err);
1061 }
1062 EXPORT_SYMBOL(p9_client_create);
1063 
1064 void p9_client_destroy(struct p9_client *clnt)
1065 {
1066 	struct p9_fid *fid, *fidptr;
1067 
1068 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1069 
1070 	if (clnt->trans_mod)
1071 		clnt->trans_mod->close(clnt);
1072 
1073 	v9fs_put_trans(clnt->trans_mod);
1074 
1075 	list_for_each_entry_safe(fid, fidptr, &clnt->fidlist, flist) {
1076 		pr_info("Found fid %d not clunked\n", fid->fid);
1077 		p9_fid_destroy(fid);
1078 	}
1079 
1080 	if (clnt->fidpool)
1081 		p9_idpool_destroy(clnt->fidpool);
1082 
1083 	p9_tag_cleanup(clnt);
1084 
1085 	kfree(clnt);
1086 }
1087 EXPORT_SYMBOL(p9_client_destroy);
1088 
1089 void p9_client_disconnect(struct p9_client *clnt)
1090 {
1091 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1092 	clnt->status = Disconnected;
1093 }
1094 EXPORT_SYMBOL(p9_client_disconnect);
1095 
1096 void p9_client_begin_disconnect(struct p9_client *clnt)
1097 {
1098 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1099 	clnt->status = BeginDisconnect;
1100 }
1101 EXPORT_SYMBOL(p9_client_begin_disconnect);
1102 
1103 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1104 	const char *uname, kuid_t n_uname, const char *aname)
1105 {
1106 	int err = 0;
1107 	struct p9_req_t *req;
1108 	struct p9_fid *fid;
1109 	struct p9_qid qid;
1110 
1111 
1112 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1113 		 afid ? afid->fid : -1, uname, aname);
1114 	fid = p9_fid_create(clnt);
1115 	if (IS_ERR(fid)) {
1116 		err = PTR_ERR(fid);
1117 		fid = NULL;
1118 		goto error;
1119 	}
1120 	fid->uid = n_uname;
1121 
1122 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
1123 			afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
1124 	if (IS_ERR(req)) {
1125 		err = PTR_ERR(req);
1126 		goto error;
1127 	}
1128 
1129 	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", &qid);
1130 	if (err) {
1131 		trace_9p_protocol_dump(clnt, req->rc);
1132 		p9_free_req(clnt, req);
1133 		goto error;
1134 	}
1135 
1136 	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
1137 		 qid.type, (unsigned long long)qid.path, qid.version);
1138 
1139 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1140 
1141 	p9_free_req(clnt, req);
1142 	return fid;
1143 
1144 error:
1145 	if (fid)
1146 		p9_fid_destroy(fid);
1147 	return ERR_PTR(err);
1148 }
1149 EXPORT_SYMBOL(p9_client_attach);
1150 
1151 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
1152 		const unsigned char * const *wnames, int clone)
1153 {
1154 	int err;
1155 	struct p9_client *clnt;
1156 	struct p9_fid *fid;
1157 	struct p9_qid *wqids;
1158 	struct p9_req_t *req;
1159 	uint16_t nwqids, count;
1160 
1161 	err = 0;
1162 	wqids = NULL;
1163 	clnt = oldfid->clnt;
1164 	if (clone) {
1165 		fid = p9_fid_create(clnt);
1166 		if (IS_ERR(fid)) {
1167 			err = PTR_ERR(fid);
1168 			fid = NULL;
1169 			goto error;
1170 		}
1171 
1172 		fid->uid = oldfid->uid;
1173 	} else
1174 		fid = oldfid;
1175 
1176 
1177 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1178 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1179 
1180 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1181 								nwname, wnames);
1182 	if (IS_ERR(req)) {
1183 		err = PTR_ERR(req);
1184 		goto error;
1185 	}
1186 
1187 	err = p9pdu_readf(req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1188 	if (err) {
1189 		trace_9p_protocol_dump(clnt, req->rc);
1190 		p9_free_req(clnt, req);
1191 		goto clunk_fid;
1192 	}
1193 	p9_free_req(clnt, req);
1194 
1195 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1196 
1197 	if (nwqids != nwname) {
1198 		err = -ENOENT;
1199 		goto clunk_fid;
1200 	}
1201 
1202 	for (count = 0; count < nwqids; count++)
1203 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1204 			count, wqids[count].type,
1205 			(unsigned long long)wqids[count].path,
1206 			wqids[count].version);
1207 
1208 	if (nwname)
1209 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1210 	else
1211 		fid->qid = oldfid->qid;
1212 
1213 	kfree(wqids);
1214 	return fid;
1215 
1216 clunk_fid:
1217 	kfree(wqids);
1218 	p9_client_clunk(fid);
1219 	fid = NULL;
1220 
1221 error:
1222 	if (fid && (fid != oldfid))
1223 		p9_fid_destroy(fid);
1224 
1225 	return ERR_PTR(err);
1226 }
1227 EXPORT_SYMBOL(p9_client_walk);
1228 
1229 int p9_client_open(struct p9_fid *fid, int mode)
1230 {
1231 	int err;
1232 	struct p9_client *clnt;
1233 	struct p9_req_t *req;
1234 	struct p9_qid qid;
1235 	int iounit;
1236 
1237 	clnt = fid->clnt;
1238 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1239 		p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1240 	err = 0;
1241 
1242 	if (fid->mode != -1)
1243 		return -EINVAL;
1244 
1245 	if (p9_is_proto_dotl(clnt))
1246 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode);
1247 	else
1248 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
1249 	if (IS_ERR(req)) {
1250 		err = PTR_ERR(req);
1251 		goto error;
1252 	}
1253 
1254 	err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1255 	if (err) {
1256 		trace_9p_protocol_dump(clnt, req->rc);
1257 		goto free_and_error;
1258 	}
1259 
1260 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1261 		p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1262 		(unsigned long long)qid.path, qid.version, iounit);
1263 
1264 	fid->mode = mode;
1265 	fid->iounit = iounit;
1266 
1267 free_and_error:
1268 	p9_free_req(clnt, req);
1269 error:
1270 	return err;
1271 }
1272 EXPORT_SYMBOL(p9_client_open);
1273 
1274 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags, u32 mode,
1275 		kgid_t gid, struct p9_qid *qid)
1276 {
1277 	int err = 0;
1278 	struct p9_client *clnt;
1279 	struct p9_req_t *req;
1280 	int iounit;
1281 
1282 	p9_debug(P9_DEBUG_9P,
1283 			">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1284 			ofid->fid, name, flags, mode,
1285 		 	from_kgid(&init_user_ns, gid));
1286 	clnt = ofid->clnt;
1287 
1288 	if (ofid->mode != -1)
1289 		return -EINVAL;
1290 
1291 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1292 			mode, gid);
1293 	if (IS_ERR(req)) {
1294 		err = PTR_ERR(req);
1295 		goto error;
1296 	}
1297 
1298 	err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", qid, &iounit);
1299 	if (err) {
1300 		trace_9p_protocol_dump(clnt, req->rc);
1301 		goto free_and_error;
1302 	}
1303 
1304 	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1305 			qid->type,
1306 			(unsigned long long)qid->path,
1307 			qid->version, iounit);
1308 
1309 	ofid->mode = mode;
1310 	ofid->iounit = iounit;
1311 
1312 free_and_error:
1313 	p9_free_req(clnt, req);
1314 error:
1315 	return err;
1316 }
1317 EXPORT_SYMBOL(p9_client_create_dotl);
1318 
1319 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1320 		     char *extension)
1321 {
1322 	int err;
1323 	struct p9_client *clnt;
1324 	struct p9_req_t *req;
1325 	struct p9_qid qid;
1326 	int iounit;
1327 
1328 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1329 						fid->fid, name, perm, mode);
1330 	err = 0;
1331 	clnt = fid->clnt;
1332 
1333 	if (fid->mode != -1)
1334 		return -EINVAL;
1335 
1336 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1337 				mode, extension);
1338 	if (IS_ERR(req)) {
1339 		err = PTR_ERR(req);
1340 		goto error;
1341 	}
1342 
1343 	err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1344 	if (err) {
1345 		trace_9p_protocol_dump(clnt, req->rc);
1346 		goto free_and_error;
1347 	}
1348 
1349 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1350 				qid.type,
1351 				(unsigned long long)qid.path,
1352 				qid.version, iounit);
1353 
1354 	fid->mode = mode;
1355 	fid->iounit = iounit;
1356 
1357 free_and_error:
1358 	p9_free_req(clnt, req);
1359 error:
1360 	return err;
1361 }
1362 EXPORT_SYMBOL(p9_client_fcreate);
1363 
1364 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1365 		const char *symtgt, kgid_t gid, struct p9_qid *qid)
1366 {
1367 	int err = 0;
1368 	struct p9_client *clnt;
1369 	struct p9_req_t *req;
1370 
1371 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1372 			dfid->fid, name, symtgt);
1373 	clnt = dfid->clnt;
1374 
1375 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1376 			gid);
1377 	if (IS_ERR(req)) {
1378 		err = PTR_ERR(req);
1379 		goto error;
1380 	}
1381 
1382 	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
1383 	if (err) {
1384 		trace_9p_protocol_dump(clnt, req->rc);
1385 		goto free_and_error;
1386 	}
1387 
1388 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1389 			qid->type, (unsigned long long)qid->path, qid->version);
1390 
1391 free_and_error:
1392 	p9_free_req(clnt, req);
1393 error:
1394 	return err;
1395 }
1396 EXPORT_SYMBOL(p9_client_symlink);
1397 
1398 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1399 {
1400 	struct p9_client *clnt;
1401 	struct p9_req_t *req;
1402 
1403 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1404 			dfid->fid, oldfid->fid, newname);
1405 	clnt = dfid->clnt;
1406 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1407 			newname);
1408 	if (IS_ERR(req))
1409 		return PTR_ERR(req);
1410 
1411 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1412 	p9_free_req(clnt, req);
1413 	return 0;
1414 }
1415 EXPORT_SYMBOL(p9_client_link);
1416 
1417 int p9_client_fsync(struct p9_fid *fid, int datasync)
1418 {
1419 	int err;
1420 	struct p9_client *clnt;
1421 	struct p9_req_t *req;
1422 
1423 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1424 			fid->fid, datasync);
1425 	err = 0;
1426 	clnt = fid->clnt;
1427 
1428 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1429 	if (IS_ERR(req)) {
1430 		err = PTR_ERR(req);
1431 		goto error;
1432 	}
1433 
1434 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1435 
1436 	p9_free_req(clnt, req);
1437 
1438 error:
1439 	return err;
1440 }
1441 EXPORT_SYMBOL(p9_client_fsync);
1442 
1443 int p9_client_clunk(struct p9_fid *fid)
1444 {
1445 	int err;
1446 	struct p9_client *clnt;
1447 	struct p9_req_t *req;
1448 	int retries = 0;
1449 
1450 	if (!fid) {
1451 		pr_warn("%s (%d): Trying to clunk with NULL fid\n",
1452 			__func__, task_pid_nr(current));
1453 		dump_stack();
1454 		return 0;
1455 	}
1456 
1457 again:
1458 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n", fid->fid,
1459 								retries);
1460 	err = 0;
1461 	clnt = fid->clnt;
1462 
1463 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1464 	if (IS_ERR(req)) {
1465 		err = PTR_ERR(req);
1466 		goto error;
1467 	}
1468 
1469 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1470 
1471 	p9_free_req(clnt, req);
1472 error:
1473 	/*
1474 	 * Fid is not valid even after a failed clunk
1475 	 * If interrupted, retry once then give up and
1476 	 * leak fid until umount.
1477 	 */
1478 	if (err == -ERESTARTSYS) {
1479 		if (retries++ == 0)
1480 			goto again;
1481 	} else
1482 		p9_fid_destroy(fid);
1483 	return err;
1484 }
1485 EXPORT_SYMBOL(p9_client_clunk);
1486 
1487 int p9_client_remove(struct p9_fid *fid)
1488 {
1489 	int err;
1490 	struct p9_client *clnt;
1491 	struct p9_req_t *req;
1492 
1493 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1494 	err = 0;
1495 	clnt = fid->clnt;
1496 
1497 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1498 	if (IS_ERR(req)) {
1499 		err = PTR_ERR(req);
1500 		goto error;
1501 	}
1502 
1503 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1504 
1505 	p9_free_req(clnt, req);
1506 error:
1507 	if (err == -ERESTARTSYS)
1508 		p9_client_clunk(fid);
1509 	else
1510 		p9_fid_destroy(fid);
1511 	return err;
1512 }
1513 EXPORT_SYMBOL(p9_client_remove);
1514 
1515 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1516 {
1517 	int err = 0;
1518 	struct p9_req_t *req;
1519 	struct p9_client *clnt;
1520 
1521 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1522 		   dfid->fid, name, flags);
1523 
1524 	clnt = dfid->clnt;
1525 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1526 	if (IS_ERR(req)) {
1527 		err = PTR_ERR(req);
1528 		goto error;
1529 	}
1530 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1531 
1532 	p9_free_req(clnt, req);
1533 error:
1534 	return err;
1535 }
1536 EXPORT_SYMBOL(p9_client_unlinkat);
1537 
1538 int
1539 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1540 {
1541 	struct p9_client *clnt = fid->clnt;
1542 	struct p9_req_t *req;
1543 	int total = 0;
1544 	*err = 0;
1545 
1546 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n",
1547 		   fid->fid, (unsigned long long) offset, (int)iov_iter_count(to));
1548 
1549 	while (iov_iter_count(to)) {
1550 		int count = iov_iter_count(to);
1551 		int rsize, non_zc = 0;
1552 		char *dataptr;
1553 
1554 		rsize = fid->iounit;
1555 		if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1556 			rsize = clnt->msize - P9_IOHDRSZ;
1557 
1558 		if (count < rsize)
1559 			rsize = count;
1560 
1561 		/* Don't bother zerocopy for small IO (< 1024) */
1562 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1563 			/*
1564 			 * response header len is 11
1565 			 * PDU Header(7) + IO Size (4)
1566 			 */
1567 			req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1568 					       0, 11, "dqd", fid->fid,
1569 					       offset, rsize);
1570 		} else {
1571 			non_zc = 1;
1572 			req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1573 					    rsize);
1574 		}
1575 		if (IS_ERR(req)) {
1576 			*err = PTR_ERR(req);
1577 			break;
1578 		}
1579 
1580 		*err = p9pdu_readf(req->rc, clnt->proto_version,
1581 				   "D", &count, &dataptr);
1582 		if (*err) {
1583 			trace_9p_protocol_dump(clnt, req->rc);
1584 			p9_free_req(clnt, req);
1585 			break;
1586 		}
1587 		if (rsize < count) {
1588 			pr_err("bogus RREAD count (%d > %d)\n", count, rsize);
1589 			count = rsize;
1590 		}
1591 
1592 		p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1593 		if (!count) {
1594 			p9_free_req(clnt, req);
1595 			break;
1596 		}
1597 
1598 		if (non_zc) {
1599 			int n = copy_to_iter(dataptr, count, to);
1600 			total += n;
1601 			offset += n;
1602 			if (n != count) {
1603 				*err = -EFAULT;
1604 				p9_free_req(clnt, req);
1605 				break;
1606 			}
1607 		} else {
1608 			iov_iter_advance(to, count);
1609 			total += count;
1610 			offset += count;
1611 		}
1612 		p9_free_req(clnt, req);
1613 	}
1614 	return total;
1615 }
1616 EXPORT_SYMBOL(p9_client_read);
1617 
1618 int
1619 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1620 {
1621 	struct p9_client *clnt = fid->clnt;
1622 	struct p9_req_t *req;
1623 	int total = 0;
1624 	*err = 0;
1625 
1626 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n",
1627 				fid->fid, (unsigned long long) offset,
1628 				iov_iter_count(from));
1629 
1630 	while (iov_iter_count(from)) {
1631 		int count = iov_iter_count(from);
1632 		int rsize = fid->iounit;
1633 		if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1634 			rsize = clnt->msize - P9_IOHDRSZ;
1635 
1636 		if (count < rsize)
1637 			rsize = count;
1638 
1639 		/* Don't bother zerocopy for small IO (< 1024) */
1640 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1641 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1642 					       rsize, P9_ZC_HDR_SZ, "dqd",
1643 					       fid->fid, offset, rsize);
1644 		} else {
1645 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1646 						    offset, rsize, from);
1647 		}
1648 		if (IS_ERR(req)) {
1649 			*err = PTR_ERR(req);
1650 			break;
1651 		}
1652 
1653 		*err = p9pdu_readf(req->rc, clnt->proto_version, "d", &count);
1654 		if (*err) {
1655 			trace_9p_protocol_dump(clnt, req->rc);
1656 			p9_free_req(clnt, req);
1657 			break;
1658 		}
1659 		if (rsize < count) {
1660 			pr_err("bogus RWRITE count (%d > %d)\n", count, rsize);
1661 			count = rsize;
1662 		}
1663 
1664 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1665 
1666 		p9_free_req(clnt, req);
1667 		iov_iter_advance(from, count);
1668 		total += count;
1669 		offset += count;
1670 	}
1671 	return total;
1672 }
1673 EXPORT_SYMBOL(p9_client_write);
1674 
1675 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1676 {
1677 	int err;
1678 	struct p9_client *clnt;
1679 	struct p9_wstat *ret = kmalloc(sizeof(struct p9_wstat), GFP_KERNEL);
1680 	struct p9_req_t *req;
1681 	u16 ignored;
1682 
1683 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1684 
1685 	if (!ret)
1686 		return ERR_PTR(-ENOMEM);
1687 
1688 	err = 0;
1689 	clnt = fid->clnt;
1690 
1691 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1692 	if (IS_ERR(req)) {
1693 		err = PTR_ERR(req);
1694 		goto error;
1695 	}
1696 
1697 	err = p9pdu_readf(req->rc, clnt->proto_version, "wS", &ignored, ret);
1698 	if (err) {
1699 		trace_9p_protocol_dump(clnt, req->rc);
1700 		p9_free_req(clnt, req);
1701 		goto error;
1702 	}
1703 
1704 	p9_debug(P9_DEBUG_9P,
1705 		"<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1706 		"<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1707 		"<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1708 		"<<<    uid=%d gid=%d n_muid=%d\n",
1709 		ret->size, ret->type, ret->dev, ret->qid.type,
1710 		(unsigned long long)ret->qid.path, ret->qid.version, ret->mode,
1711 		ret->atime, ret->mtime, (unsigned long long)ret->length,
1712 		ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1713 		from_kuid(&init_user_ns, ret->n_uid),
1714 		from_kgid(&init_user_ns, ret->n_gid),
1715 		from_kuid(&init_user_ns, ret->n_muid));
1716 
1717 	p9_free_req(clnt, req);
1718 	return ret;
1719 
1720 error:
1721 	kfree(ret);
1722 	return ERR_PTR(err);
1723 }
1724 EXPORT_SYMBOL(p9_client_stat);
1725 
1726 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1727 							u64 request_mask)
1728 {
1729 	int err;
1730 	struct p9_client *clnt;
1731 	struct p9_stat_dotl *ret = kmalloc(sizeof(struct p9_stat_dotl),
1732 								GFP_KERNEL);
1733 	struct p9_req_t *req;
1734 
1735 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1736 							fid->fid, request_mask);
1737 
1738 	if (!ret)
1739 		return ERR_PTR(-ENOMEM);
1740 
1741 	err = 0;
1742 	clnt = fid->clnt;
1743 
1744 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1745 	if (IS_ERR(req)) {
1746 		err = PTR_ERR(req);
1747 		goto error;
1748 	}
1749 
1750 	err = p9pdu_readf(req->rc, clnt->proto_version, "A", ret);
1751 	if (err) {
1752 		trace_9p_protocol_dump(clnt, req->rc);
1753 		p9_free_req(clnt, req);
1754 		goto error;
1755 	}
1756 
1757 	p9_debug(P9_DEBUG_9P,
1758 		"<<< RGETATTR st_result_mask=%lld\n"
1759 		"<<< qid=%x.%llx.%x\n"
1760 		"<<< st_mode=%8.8x st_nlink=%llu\n"
1761 		"<<< st_uid=%d st_gid=%d\n"
1762 		"<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1763 		"<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1764 		"<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1765 		"<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1766 		"<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1767 		"<<< st_gen=%lld st_data_version=%lld",
1768 		ret->st_result_mask, ret->qid.type, ret->qid.path,
1769 		ret->qid.version, ret->st_mode, ret->st_nlink,
1770 		from_kuid(&init_user_ns, ret->st_uid),
1771 		from_kgid(&init_user_ns, ret->st_gid),
1772 		ret->st_rdev, ret->st_size, ret->st_blksize,
1773 		ret->st_blocks, ret->st_atime_sec, ret->st_atime_nsec,
1774 		ret->st_mtime_sec, ret->st_mtime_nsec, ret->st_ctime_sec,
1775 		ret->st_ctime_nsec, ret->st_btime_sec, ret->st_btime_nsec,
1776 		ret->st_gen, ret->st_data_version);
1777 
1778 	p9_free_req(clnt, req);
1779 	return ret;
1780 
1781 error:
1782 	kfree(ret);
1783 	return ERR_PTR(err);
1784 }
1785 EXPORT_SYMBOL(p9_client_getattr_dotl);
1786 
1787 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1788 {
1789 	int ret;
1790 
1791 	/* NOTE: size shouldn't include its own length */
1792 	/* size[2] type[2] dev[4] qid[13] */
1793 	/* mode[4] atime[4] mtime[4] length[8]*/
1794 	/* name[s] uid[s] gid[s] muid[s] */
1795 	ret = 2+4+13+4+4+4+8+2+2+2+2;
1796 
1797 	if (wst->name)
1798 		ret += strlen(wst->name);
1799 	if (wst->uid)
1800 		ret += strlen(wst->uid);
1801 	if (wst->gid)
1802 		ret += strlen(wst->gid);
1803 	if (wst->muid)
1804 		ret += strlen(wst->muid);
1805 
1806 	if ((proto_version == p9_proto_2000u) ||
1807 		(proto_version == p9_proto_2000L)) {
1808 		ret += 2+4+4+4;	/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1809 		if (wst->extension)
1810 			ret += strlen(wst->extension);
1811 	}
1812 
1813 	return ret;
1814 }
1815 
1816 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1817 {
1818 	int err;
1819 	struct p9_req_t *req;
1820 	struct p9_client *clnt;
1821 
1822 	err = 0;
1823 	clnt = fid->clnt;
1824 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1825 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n", fid->fid);
1826 	p9_debug(P9_DEBUG_9P,
1827 		"     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1828 		"     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1829 		"     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1830 		"     uid=%d gid=%d n_muid=%d\n",
1831 		wst->size, wst->type, wst->dev, wst->qid.type,
1832 		(unsigned long long)wst->qid.path, wst->qid.version, wst->mode,
1833 		wst->atime, wst->mtime, (unsigned long long)wst->length,
1834 		wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1835 		from_kuid(&init_user_ns, wst->n_uid),
1836 		from_kgid(&init_user_ns, wst->n_gid),
1837 		from_kuid(&init_user_ns, wst->n_muid));
1838 
1839 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS", fid->fid, wst->size+2, wst);
1840 	if (IS_ERR(req)) {
1841 		err = PTR_ERR(req);
1842 		goto error;
1843 	}
1844 
1845 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1846 
1847 	p9_free_req(clnt, req);
1848 error:
1849 	return err;
1850 }
1851 EXPORT_SYMBOL(p9_client_wstat);
1852 
1853 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1854 {
1855 	int err;
1856 	struct p9_req_t *req;
1857 	struct p9_client *clnt;
1858 
1859 	err = 0;
1860 	clnt = fid->clnt;
1861 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1862 	p9_debug(P9_DEBUG_9P,
1863 		"    valid=%x mode=%x uid=%d gid=%d size=%lld\n"
1864 		"    atime_sec=%lld atime_nsec=%lld\n"
1865 		"    mtime_sec=%lld mtime_nsec=%lld\n",
1866 		p9attr->valid, p9attr->mode,
1867 		from_kuid(&init_user_ns, p9attr->uid),
1868 		from_kgid(&init_user_ns, p9attr->gid),
1869 		p9attr->size, p9attr->atime_sec, p9attr->atime_nsec,
1870 		p9attr->mtime_sec, p9attr->mtime_nsec);
1871 
1872 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1873 
1874 	if (IS_ERR(req)) {
1875 		err = PTR_ERR(req);
1876 		goto error;
1877 	}
1878 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1879 	p9_free_req(clnt, req);
1880 error:
1881 	return err;
1882 }
1883 EXPORT_SYMBOL(p9_client_setattr);
1884 
1885 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1886 {
1887 	int err;
1888 	struct p9_req_t *req;
1889 	struct p9_client *clnt;
1890 
1891 	err = 0;
1892 	clnt = fid->clnt;
1893 
1894 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1895 
1896 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1897 	if (IS_ERR(req)) {
1898 		err = PTR_ERR(req);
1899 		goto error;
1900 	}
1901 
1902 	err = p9pdu_readf(req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1903 		&sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1904 		&sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1905 	if (err) {
1906 		trace_9p_protocol_dump(clnt, req->rc);
1907 		p9_free_req(clnt, req);
1908 		goto error;
1909 	}
1910 
1911 	p9_debug(P9_DEBUG_9P, "<<< RSTATFS fid %d type 0x%lx bsize %ld "
1912 		"blocks %llu bfree %llu bavail %llu files %llu ffree %llu "
1913 		"fsid %llu namelen %ld\n",
1914 		fid->fid, (long unsigned int)sb->type, (long int)sb->bsize,
1915 		sb->blocks, sb->bfree, sb->bavail, sb->files,  sb->ffree,
1916 		sb->fsid, (long int)sb->namelen);
1917 
1918 	p9_free_req(clnt, req);
1919 error:
1920 	return err;
1921 }
1922 EXPORT_SYMBOL(p9_client_statfs);
1923 
1924 int p9_client_rename(struct p9_fid *fid,
1925 		     struct p9_fid *newdirfid, const char *name)
1926 {
1927 	int err;
1928 	struct p9_req_t *req;
1929 	struct p9_client *clnt;
1930 
1931 	err = 0;
1932 	clnt = fid->clnt;
1933 
1934 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1935 			fid->fid, newdirfid->fid, name);
1936 
1937 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1938 			newdirfid->fid, name);
1939 	if (IS_ERR(req)) {
1940 		err = PTR_ERR(req);
1941 		goto error;
1942 	}
1943 
1944 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1945 
1946 	p9_free_req(clnt, req);
1947 error:
1948 	return err;
1949 }
1950 EXPORT_SYMBOL(p9_client_rename);
1951 
1952 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
1953 		       struct p9_fid *newdirfid, const char *new_name)
1954 {
1955 	int err;
1956 	struct p9_req_t *req;
1957 	struct p9_client *clnt;
1958 
1959 	err = 0;
1960 	clnt = olddirfid->clnt;
1961 
1962 	p9_debug(P9_DEBUG_9P, ">>> TRENAMEAT olddirfid %d old name %s"
1963 		   " newdirfid %d new name %s\n", olddirfid->fid, old_name,
1964 		   newdirfid->fid, new_name);
1965 
1966 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
1967 			    old_name, newdirfid->fid, new_name);
1968 	if (IS_ERR(req)) {
1969 		err = PTR_ERR(req);
1970 		goto error;
1971 	}
1972 
1973 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
1974 		   newdirfid->fid, new_name);
1975 
1976 	p9_free_req(clnt, req);
1977 error:
1978 	return err;
1979 }
1980 EXPORT_SYMBOL(p9_client_renameat);
1981 
1982 /*
1983  * An xattrwalk without @attr_name gives the fid for the lisxattr namespace
1984  */
1985 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
1986 				const char *attr_name, u64 *attr_size)
1987 {
1988 	int err;
1989 	struct p9_req_t *req;
1990 	struct p9_client *clnt;
1991 	struct p9_fid *attr_fid;
1992 
1993 	err = 0;
1994 	clnt = file_fid->clnt;
1995 	attr_fid = p9_fid_create(clnt);
1996 	if (IS_ERR(attr_fid)) {
1997 		err = PTR_ERR(attr_fid);
1998 		attr_fid = NULL;
1999 		goto error;
2000 	}
2001 	p9_debug(P9_DEBUG_9P,
2002 		">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
2003 		file_fid->fid, attr_fid->fid, attr_name);
2004 
2005 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
2006 			file_fid->fid, attr_fid->fid, attr_name);
2007 	if (IS_ERR(req)) {
2008 		err = PTR_ERR(req);
2009 		goto error;
2010 	}
2011 	err = p9pdu_readf(req->rc, clnt->proto_version, "q", attr_size);
2012 	if (err) {
2013 		trace_9p_protocol_dump(clnt, req->rc);
2014 		p9_free_req(clnt, req);
2015 		goto clunk_fid;
2016 	}
2017 	p9_free_req(clnt, req);
2018 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
2019 		attr_fid->fid, *attr_size);
2020 	return attr_fid;
2021 clunk_fid:
2022 	p9_client_clunk(attr_fid);
2023 	attr_fid = NULL;
2024 error:
2025 	if (attr_fid && (attr_fid != file_fid))
2026 		p9_fid_destroy(attr_fid);
2027 
2028 	return ERR_PTR(err);
2029 }
2030 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
2031 
2032 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
2033 			u64 attr_size, int flags)
2034 {
2035 	int err;
2036 	struct p9_req_t *req;
2037 	struct p9_client *clnt;
2038 
2039 	p9_debug(P9_DEBUG_9P,
2040 		">>> TXATTRCREATE fid %d name  %s size %lld flag %d\n",
2041 		fid->fid, name, (long long)attr_size, flags);
2042 	err = 0;
2043 	clnt = fid->clnt;
2044 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
2045 			fid->fid, name, attr_size, flags);
2046 	if (IS_ERR(req)) {
2047 		err = PTR_ERR(req);
2048 		goto error;
2049 	}
2050 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
2051 	p9_free_req(clnt, req);
2052 error:
2053 	return err;
2054 }
2055 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
2056 
2057 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
2058 {
2059 	int err, rsize, non_zc = 0;
2060 	struct p9_client *clnt;
2061 	struct p9_req_t *req;
2062 	char *dataptr;
2063 	struct kvec kv = {.iov_base = data, .iov_len = count};
2064 	struct iov_iter to;
2065 
2066 	iov_iter_kvec(&to, READ | ITER_KVEC, &kv, 1, count);
2067 
2068 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
2069 				fid->fid, (unsigned long long) offset, count);
2070 
2071 	err = 0;
2072 	clnt = fid->clnt;
2073 
2074 	rsize = fid->iounit;
2075 	if (!rsize || rsize > clnt->msize-P9_READDIRHDRSZ)
2076 		rsize = clnt->msize - P9_READDIRHDRSZ;
2077 
2078 	if (count < rsize)
2079 		rsize = count;
2080 
2081 	/* Don't bother zerocopy for small IO (< 1024) */
2082 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2083 		/*
2084 		 * response header len is 11
2085 		 * PDU Header(7) + IO Size (4)
2086 		 */
2087 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2088 				       11, "dqd", fid->fid, offset, rsize);
2089 	} else {
2090 		non_zc = 1;
2091 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2092 				    offset, rsize);
2093 	}
2094 	if (IS_ERR(req)) {
2095 		err = PTR_ERR(req);
2096 		goto error;
2097 	}
2098 
2099 	err = p9pdu_readf(req->rc, clnt->proto_version, "D", &count, &dataptr);
2100 	if (err) {
2101 		trace_9p_protocol_dump(clnt, req->rc);
2102 		goto free_and_error;
2103 	}
2104 	if (rsize < count) {
2105 		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
2106 		count = rsize;
2107 	}
2108 
2109 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
2110 
2111 	if (non_zc)
2112 		memmove(data, dataptr, count);
2113 
2114 	p9_free_req(clnt, req);
2115 	return count;
2116 
2117 free_and_error:
2118 	p9_free_req(clnt, req);
2119 error:
2120 	return err;
2121 }
2122 EXPORT_SYMBOL(p9_client_readdir);
2123 
2124 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2125 			dev_t rdev, kgid_t gid, struct p9_qid *qid)
2126 {
2127 	int err;
2128 	struct p9_client *clnt;
2129 	struct p9_req_t *req;
2130 
2131 	err = 0;
2132 	clnt = fid->clnt;
2133 	p9_debug(P9_DEBUG_9P, ">>> TMKNOD fid %d name %s mode %d major %d "
2134 		"minor %d\n", fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2135 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2136 		MAJOR(rdev), MINOR(rdev), gid);
2137 	if (IS_ERR(req))
2138 		return PTR_ERR(req);
2139 
2140 	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
2141 	if (err) {
2142 		trace_9p_protocol_dump(clnt, req->rc);
2143 		goto error;
2144 	}
2145 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n", qid->type,
2146 				(unsigned long long)qid->path, qid->version);
2147 
2148 error:
2149 	p9_free_req(clnt, req);
2150 	return err;
2151 
2152 }
2153 EXPORT_SYMBOL(p9_client_mknod_dotl);
2154 
2155 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2156 				kgid_t gid, struct p9_qid *qid)
2157 {
2158 	int err;
2159 	struct p9_client *clnt;
2160 	struct p9_req_t *req;
2161 
2162 	err = 0;
2163 	clnt = fid->clnt;
2164 	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
2165 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
2166 	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg", fid->fid, name, mode,
2167 		gid);
2168 	if (IS_ERR(req))
2169 		return PTR_ERR(req);
2170 
2171 	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
2172 	if (err) {
2173 		trace_9p_protocol_dump(clnt, req->rc);
2174 		goto error;
2175 	}
2176 	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
2177 				(unsigned long long)qid->path, qid->version);
2178 
2179 error:
2180 	p9_free_req(clnt, req);
2181 	return err;
2182 
2183 }
2184 EXPORT_SYMBOL(p9_client_mkdir_dotl);
2185 
2186 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
2187 {
2188 	int err;
2189 	struct p9_client *clnt;
2190 	struct p9_req_t *req;
2191 
2192 	err = 0;
2193 	clnt = fid->clnt;
2194 	p9_debug(P9_DEBUG_9P, ">>> TLOCK fid %d type %i flags %d "
2195 			"start %lld length %lld proc_id %d client_id %s\n",
2196 			fid->fid, flock->type, flock->flags, flock->start,
2197 			flock->length, flock->proc_id, flock->client_id);
2198 
2199 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2200 				flock->flags, flock->start, flock->length,
2201 					flock->proc_id, flock->client_id);
2202 
2203 	if (IS_ERR(req))
2204 		return PTR_ERR(req);
2205 
2206 	err = p9pdu_readf(req->rc, clnt->proto_version, "b", status);
2207 	if (err) {
2208 		trace_9p_protocol_dump(clnt, req->rc);
2209 		goto error;
2210 	}
2211 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2212 error:
2213 	p9_free_req(clnt, req);
2214 	return err;
2215 
2216 }
2217 EXPORT_SYMBOL(p9_client_lock_dotl);
2218 
2219 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2220 {
2221 	int err;
2222 	struct p9_client *clnt;
2223 	struct p9_req_t *req;
2224 
2225 	err = 0;
2226 	clnt = fid->clnt;
2227 	p9_debug(P9_DEBUG_9P, ">>> TGETLOCK fid %d, type %i start %lld "
2228 		"length %lld proc_id %d client_id %s\n", fid->fid, glock->type,
2229 		glock->start, glock->length, glock->proc_id, glock->client_id);
2230 
2231 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,  glock->type,
2232 		glock->start, glock->length, glock->proc_id, glock->client_id);
2233 
2234 	if (IS_ERR(req))
2235 		return PTR_ERR(req);
2236 
2237 	err = p9pdu_readf(req->rc, clnt->proto_version, "bqqds", &glock->type,
2238 			&glock->start, &glock->length, &glock->proc_id,
2239 			&glock->client_id);
2240 	if (err) {
2241 		trace_9p_protocol_dump(clnt, req->rc);
2242 		goto error;
2243 	}
2244 	p9_debug(P9_DEBUG_9P, "<<< RGETLOCK type %i start %lld length %lld "
2245 		"proc_id %d client_id %s\n", glock->type, glock->start,
2246 		glock->length, glock->proc_id, glock->client_id);
2247 error:
2248 	p9_free_req(clnt, req);
2249 	return err;
2250 }
2251 EXPORT_SYMBOL(p9_client_getlock_dotl);
2252 
2253 int p9_client_readlink(struct p9_fid *fid, char **target)
2254 {
2255 	int err;
2256 	struct p9_client *clnt;
2257 	struct p9_req_t *req;
2258 
2259 	err = 0;
2260 	clnt = fid->clnt;
2261 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2262 
2263 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2264 	if (IS_ERR(req))
2265 		return PTR_ERR(req);
2266 
2267 	err = p9pdu_readf(req->rc, clnt->proto_version, "s", target);
2268 	if (err) {
2269 		trace_9p_protocol_dump(clnt, req->rc);
2270 		goto error;
2271 	}
2272 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2273 error:
2274 	p9_free_req(clnt, req);
2275 	return err;
2276 }
2277 EXPORT_SYMBOL(p9_client_readlink);
2278