xref: /openbmc/linux/net/9p/client.c (revision 1c2dd16a)
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 			if (!copy_from_iter_full(ename + inline_len,
596 					     len - inline_len, uidata)) {
597 				err = -EFAULT;
598 				goto out_err;
599 			}
600 		}
601 		ename = NULL;
602 		err = p9pdu_readf(req->rc, c->proto_version, "s?d",
603 				  &ename, &ecode);
604 		if (err)
605 			goto out_err;
606 
607 		if (p9_is_proto_dotu(c) && ecode < 512)
608 			err = -ecode;
609 
610 		if (!err) {
611 			err = p9_errstr2errno(ename, strlen(ename));
612 
613 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
614 				 -ecode, ename);
615 		}
616 		kfree(ename);
617 	} else {
618 		err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode);
619 		err = -ecode;
620 
621 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
622 	}
623 	return err;
624 
625 out_err:
626 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
627 	return err;
628 }
629 
630 static struct p9_req_t *
631 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
632 
633 /**
634  * p9_client_flush - flush (cancel) a request
635  * @c: client state
636  * @oldreq: request to cancel
637  *
638  * This sents a flush for a particular request and links
639  * the flush request to the original request.  The current
640  * code only supports a single flush request although the protocol
641  * allows for multiple flush requests to be sent for a single request.
642  *
643  */
644 
645 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
646 {
647 	struct p9_req_t *req;
648 	int16_t oldtag;
649 	int err;
650 
651 	err = p9_parse_header(oldreq->tc, NULL, NULL, &oldtag, 1);
652 	if (err)
653 		return err;
654 
655 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
656 
657 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
658 	if (IS_ERR(req))
659 		return PTR_ERR(req);
660 
661 	/*
662 	 * if we haven't received a response for oldreq,
663 	 * remove it from the list
664 	 */
665 	if (oldreq->status == REQ_STATUS_SENT)
666 		if (c->trans_mod->cancelled)
667 			c->trans_mod->cancelled(c, oldreq);
668 
669 	p9_free_req(c, req);
670 	return 0;
671 }
672 
673 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
674 					      int8_t type, int req_size,
675 					      const char *fmt, va_list ap)
676 {
677 	int tag, err;
678 	struct p9_req_t *req;
679 
680 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
681 
682 	/* we allow for any status other than disconnected */
683 	if (c->status == Disconnected)
684 		return ERR_PTR(-EIO);
685 
686 	/* if status is begin_disconnected we allow only clunk request */
687 	if ((c->status == BeginDisconnect) && (type != P9_TCLUNK))
688 		return ERR_PTR(-EIO);
689 
690 	tag = P9_NOTAG;
691 	if (type != P9_TVERSION) {
692 		tag = p9_idpool_get(c->tagpool);
693 		if (tag < 0)
694 			return ERR_PTR(-ENOMEM);
695 	}
696 
697 	req = p9_tag_alloc(c, tag, req_size);
698 	if (IS_ERR(req))
699 		return req;
700 
701 	/* marshall the data */
702 	p9pdu_prepare(req->tc, tag, type);
703 	err = p9pdu_vwritef(req->tc, c->proto_version, fmt, ap);
704 	if (err)
705 		goto reterr;
706 	p9pdu_finalize(c, req->tc);
707 	trace_9p_client_req(c, type, tag);
708 	return req;
709 reterr:
710 	p9_free_req(c, req);
711 	return ERR_PTR(err);
712 }
713 
714 /**
715  * p9_client_rpc - issue a request and wait for a response
716  * @c: client session
717  * @type: type of request
718  * @fmt: protocol format string (see protocol.c)
719  *
720  * Returns request structure (which client must free using p9_free_req)
721  */
722 
723 static struct p9_req_t *
724 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
725 {
726 	va_list ap;
727 	int sigpending, err;
728 	unsigned long flags;
729 	struct p9_req_t *req;
730 
731 	va_start(ap, fmt);
732 	req = p9_client_prepare_req(c, type, c->msize, fmt, ap);
733 	va_end(ap);
734 	if (IS_ERR(req))
735 		return req;
736 
737 	if (signal_pending(current)) {
738 		sigpending = 1;
739 		clear_thread_flag(TIF_SIGPENDING);
740 	} else
741 		sigpending = 0;
742 
743 	err = c->trans_mod->request(c, req);
744 	if (err < 0) {
745 		if (err != -ERESTARTSYS && err != -EFAULT)
746 			c->status = Disconnected;
747 		goto reterr;
748 	}
749 again:
750 	/* Wait for the response */
751 	err = wait_event_interruptible(*req->wq,
752 				       req->status >= REQ_STATUS_RCVD);
753 
754 	/*
755 	 * Make sure our req is coherent with regard to updates in other
756 	 * threads - echoes to wmb() in the callback
757 	 */
758 	smp_rmb();
759 
760 	if ((err == -ERESTARTSYS) && (c->status == Connected)
761 				  && (type == P9_TFLUSH)) {
762 		sigpending = 1;
763 		clear_thread_flag(TIF_SIGPENDING);
764 		goto again;
765 	}
766 
767 	if (req->status == REQ_STATUS_ERROR) {
768 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
769 		err = req->t_err;
770 	}
771 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
772 		p9_debug(P9_DEBUG_MUX, "flushing\n");
773 		sigpending = 1;
774 		clear_thread_flag(TIF_SIGPENDING);
775 
776 		if (c->trans_mod->cancel(c, req))
777 			p9_client_flush(c, req);
778 
779 		/* if we received the response anyway, don't signal error */
780 		if (req->status == REQ_STATUS_RCVD)
781 			err = 0;
782 	}
783 	if (sigpending) {
784 		spin_lock_irqsave(&current->sighand->siglock, flags);
785 		recalc_sigpending();
786 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
787 	}
788 	if (err < 0)
789 		goto reterr;
790 
791 	err = p9_check_errors(c, req);
792 	trace_9p_client_res(c, type, req->rc->tag, err);
793 	if (!err)
794 		return req;
795 reterr:
796 	p9_free_req(c, req);
797 	return ERR_PTR(safe_errno(err));
798 }
799 
800 /**
801  * p9_client_zc_rpc - issue a request and wait for a response
802  * @c: client session
803  * @type: type of request
804  * @uidata: destination for zero copy read
805  * @uodata: source for zero copy write
806  * @inlen: read buffer size
807  * @olen: write buffer size
808  * @hdrlen: reader header size, This is the size of response protocol data
809  * @fmt: protocol format string (see protocol.c)
810  *
811  * Returns request structure (which client must free using p9_free_req)
812  */
813 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
814 					 struct iov_iter *uidata,
815 					 struct iov_iter *uodata,
816 					 int inlen, int olen, int in_hdrlen,
817 					 const char *fmt, ...)
818 {
819 	va_list ap;
820 	int sigpending, err;
821 	unsigned long flags;
822 	struct p9_req_t *req;
823 
824 	va_start(ap, fmt);
825 	/*
826 	 * We allocate a inline protocol data of only 4k bytes.
827 	 * The actual content is passed in zero-copy fashion.
828 	 */
829 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, fmt, ap);
830 	va_end(ap);
831 	if (IS_ERR(req))
832 		return req;
833 
834 	if (signal_pending(current)) {
835 		sigpending = 1;
836 		clear_thread_flag(TIF_SIGPENDING);
837 	} else
838 		sigpending = 0;
839 
840 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
841 				       inlen, olen, in_hdrlen);
842 	if (err < 0) {
843 		if (err == -EIO)
844 			c->status = Disconnected;
845 		if (err != -ERESTARTSYS)
846 			goto reterr;
847 	}
848 	if (req->status == REQ_STATUS_ERROR) {
849 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
850 		err = req->t_err;
851 	}
852 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
853 		p9_debug(P9_DEBUG_MUX, "flushing\n");
854 		sigpending = 1;
855 		clear_thread_flag(TIF_SIGPENDING);
856 
857 		if (c->trans_mod->cancel(c, req))
858 			p9_client_flush(c, req);
859 
860 		/* if we received the response anyway, don't signal error */
861 		if (req->status == REQ_STATUS_RCVD)
862 			err = 0;
863 	}
864 	if (sigpending) {
865 		spin_lock_irqsave(&current->sighand->siglock, flags);
866 		recalc_sigpending();
867 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
868 	}
869 	if (err < 0)
870 		goto reterr;
871 
872 	err = p9_check_zc_errors(c, req, uidata, in_hdrlen);
873 	trace_9p_client_res(c, type, req->rc->tag, err);
874 	if (!err)
875 		return req;
876 reterr:
877 	p9_free_req(c, req);
878 	return ERR_PTR(safe_errno(err));
879 }
880 
881 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
882 {
883 	int ret;
884 	struct p9_fid *fid;
885 	unsigned long flags;
886 
887 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
888 	fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
889 	if (!fid)
890 		return ERR_PTR(-ENOMEM);
891 
892 	ret = p9_idpool_get(clnt->fidpool);
893 	if (ret < 0) {
894 		ret = -ENOSPC;
895 		goto error;
896 	}
897 	fid->fid = ret;
898 
899 	memset(&fid->qid, 0, sizeof(struct p9_qid));
900 	fid->mode = -1;
901 	fid->uid = current_fsuid();
902 	fid->clnt = clnt;
903 	fid->rdir = NULL;
904 	spin_lock_irqsave(&clnt->lock, flags);
905 	list_add(&fid->flist, &clnt->fidlist);
906 	spin_unlock_irqrestore(&clnt->lock, flags);
907 
908 	return fid;
909 
910 error:
911 	kfree(fid);
912 	return ERR_PTR(ret);
913 }
914 
915 static void p9_fid_destroy(struct p9_fid *fid)
916 {
917 	struct p9_client *clnt;
918 	unsigned long flags;
919 
920 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
921 	clnt = fid->clnt;
922 	p9_idpool_put(fid->fid, clnt->fidpool);
923 	spin_lock_irqsave(&clnt->lock, flags);
924 	list_del(&fid->flist);
925 	spin_unlock_irqrestore(&clnt->lock, flags);
926 	kfree(fid->rdir);
927 	kfree(fid);
928 }
929 
930 static int p9_client_version(struct p9_client *c)
931 {
932 	int err = 0;
933 	struct p9_req_t *req;
934 	char *version;
935 	int msize;
936 
937 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
938 		 c->msize, c->proto_version);
939 
940 	switch (c->proto_version) {
941 	case p9_proto_2000L:
942 		req = p9_client_rpc(c, P9_TVERSION, "ds",
943 					c->msize, "9P2000.L");
944 		break;
945 	case p9_proto_2000u:
946 		req = p9_client_rpc(c, P9_TVERSION, "ds",
947 					c->msize, "9P2000.u");
948 		break;
949 	case p9_proto_legacy:
950 		req = p9_client_rpc(c, P9_TVERSION, "ds",
951 					c->msize, "9P2000");
952 		break;
953 	default:
954 		return -EINVAL;
955 	}
956 
957 	if (IS_ERR(req))
958 		return PTR_ERR(req);
959 
960 	err = p9pdu_readf(req->rc, c->proto_version, "ds", &msize, &version);
961 	if (err) {
962 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
963 		trace_9p_protocol_dump(c, req->rc);
964 		goto error;
965 	}
966 
967 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
968 	if (!strncmp(version, "9P2000.L", 8))
969 		c->proto_version = p9_proto_2000L;
970 	else if (!strncmp(version, "9P2000.u", 8))
971 		c->proto_version = p9_proto_2000u;
972 	else if (!strncmp(version, "9P2000", 6))
973 		c->proto_version = p9_proto_legacy;
974 	else {
975 		err = -EREMOTEIO;
976 		goto error;
977 	}
978 
979 	if (msize < c->msize)
980 		c->msize = msize;
981 
982 error:
983 	kfree(version);
984 	p9_free_req(c, req);
985 
986 	return err;
987 }
988 
989 struct p9_client *p9_client_create(const char *dev_name, char *options)
990 {
991 	int err;
992 	struct p9_client *clnt;
993 	char *client_id;
994 
995 	err = 0;
996 	clnt = kmalloc(sizeof(struct p9_client), GFP_KERNEL);
997 	if (!clnt)
998 		return ERR_PTR(-ENOMEM);
999 
1000 	clnt->trans_mod = NULL;
1001 	clnt->trans = NULL;
1002 
1003 	client_id = utsname()->nodename;
1004 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
1005 
1006 	spin_lock_init(&clnt->lock);
1007 	INIT_LIST_HEAD(&clnt->fidlist);
1008 
1009 	err = p9_tag_init(clnt);
1010 	if (err < 0)
1011 		goto free_client;
1012 
1013 	err = parse_opts(options, clnt);
1014 	if (err < 0)
1015 		goto destroy_tagpool;
1016 
1017 	if (!clnt->trans_mod)
1018 		clnt->trans_mod = v9fs_get_default_trans();
1019 
1020 	if (clnt->trans_mod == NULL) {
1021 		err = -EPROTONOSUPPORT;
1022 		p9_debug(P9_DEBUG_ERROR,
1023 			 "No transport defined or default transport\n");
1024 		goto destroy_tagpool;
1025 	}
1026 
1027 	clnt->fidpool = p9_idpool_create();
1028 	if (IS_ERR(clnt->fidpool)) {
1029 		err = PTR_ERR(clnt->fidpool);
1030 		goto put_trans;
1031 	}
1032 
1033 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
1034 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
1035 
1036 	err = clnt->trans_mod->create(clnt, dev_name, options);
1037 	if (err)
1038 		goto destroy_fidpool;
1039 
1040 	if (clnt->msize > clnt->trans_mod->maxsize)
1041 		clnt->msize = clnt->trans_mod->maxsize;
1042 
1043 	err = p9_client_version(clnt);
1044 	if (err)
1045 		goto close_trans;
1046 
1047 	return clnt;
1048 
1049 close_trans:
1050 	clnt->trans_mod->close(clnt);
1051 destroy_fidpool:
1052 	p9_idpool_destroy(clnt->fidpool);
1053 put_trans:
1054 	v9fs_put_trans(clnt->trans_mod);
1055 destroy_tagpool:
1056 	p9_idpool_destroy(clnt->tagpool);
1057 free_client:
1058 	kfree(clnt);
1059 	return ERR_PTR(err);
1060 }
1061 EXPORT_SYMBOL(p9_client_create);
1062 
1063 void p9_client_destroy(struct p9_client *clnt)
1064 {
1065 	struct p9_fid *fid, *fidptr;
1066 
1067 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1068 
1069 	if (clnt->trans_mod)
1070 		clnt->trans_mod->close(clnt);
1071 
1072 	v9fs_put_trans(clnt->trans_mod);
1073 
1074 	list_for_each_entry_safe(fid, fidptr, &clnt->fidlist, flist) {
1075 		pr_info("Found fid %d not clunked\n", fid->fid);
1076 		p9_fid_destroy(fid);
1077 	}
1078 
1079 	if (clnt->fidpool)
1080 		p9_idpool_destroy(clnt->fidpool);
1081 
1082 	p9_tag_cleanup(clnt);
1083 
1084 	kfree(clnt);
1085 }
1086 EXPORT_SYMBOL(p9_client_destroy);
1087 
1088 void p9_client_disconnect(struct p9_client *clnt)
1089 {
1090 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1091 	clnt->status = Disconnected;
1092 }
1093 EXPORT_SYMBOL(p9_client_disconnect);
1094 
1095 void p9_client_begin_disconnect(struct p9_client *clnt)
1096 {
1097 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1098 	clnt->status = BeginDisconnect;
1099 }
1100 EXPORT_SYMBOL(p9_client_begin_disconnect);
1101 
1102 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1103 	const char *uname, kuid_t n_uname, const char *aname)
1104 {
1105 	int err = 0;
1106 	struct p9_req_t *req;
1107 	struct p9_fid *fid;
1108 	struct p9_qid qid;
1109 
1110 
1111 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1112 		 afid ? afid->fid : -1, uname, aname);
1113 	fid = p9_fid_create(clnt);
1114 	if (IS_ERR(fid)) {
1115 		err = PTR_ERR(fid);
1116 		fid = NULL;
1117 		goto error;
1118 	}
1119 	fid->uid = n_uname;
1120 
1121 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
1122 			afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
1123 	if (IS_ERR(req)) {
1124 		err = PTR_ERR(req);
1125 		goto error;
1126 	}
1127 
1128 	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", &qid);
1129 	if (err) {
1130 		trace_9p_protocol_dump(clnt, req->rc);
1131 		p9_free_req(clnt, req);
1132 		goto error;
1133 	}
1134 
1135 	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
1136 		 qid.type, (unsigned long long)qid.path, qid.version);
1137 
1138 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1139 
1140 	p9_free_req(clnt, req);
1141 	return fid;
1142 
1143 error:
1144 	if (fid)
1145 		p9_fid_destroy(fid);
1146 	return ERR_PTR(err);
1147 }
1148 EXPORT_SYMBOL(p9_client_attach);
1149 
1150 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
1151 		const unsigned char * const *wnames, int clone)
1152 {
1153 	int err;
1154 	struct p9_client *clnt;
1155 	struct p9_fid *fid;
1156 	struct p9_qid *wqids;
1157 	struct p9_req_t *req;
1158 	uint16_t nwqids, count;
1159 
1160 	err = 0;
1161 	wqids = NULL;
1162 	clnt = oldfid->clnt;
1163 	if (clone) {
1164 		fid = p9_fid_create(clnt);
1165 		if (IS_ERR(fid)) {
1166 			err = PTR_ERR(fid);
1167 			fid = NULL;
1168 			goto error;
1169 		}
1170 
1171 		fid->uid = oldfid->uid;
1172 	} else
1173 		fid = oldfid;
1174 
1175 
1176 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1177 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1178 
1179 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1180 								nwname, wnames);
1181 	if (IS_ERR(req)) {
1182 		err = PTR_ERR(req);
1183 		goto error;
1184 	}
1185 
1186 	err = p9pdu_readf(req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1187 	if (err) {
1188 		trace_9p_protocol_dump(clnt, req->rc);
1189 		p9_free_req(clnt, req);
1190 		goto clunk_fid;
1191 	}
1192 	p9_free_req(clnt, req);
1193 
1194 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1195 
1196 	if (nwqids != nwname) {
1197 		err = -ENOENT;
1198 		goto clunk_fid;
1199 	}
1200 
1201 	for (count = 0; count < nwqids; count++)
1202 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1203 			count, wqids[count].type,
1204 			(unsigned long long)wqids[count].path,
1205 			wqids[count].version);
1206 
1207 	if (nwname)
1208 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1209 	else
1210 		fid->qid = oldfid->qid;
1211 
1212 	kfree(wqids);
1213 	return fid;
1214 
1215 clunk_fid:
1216 	kfree(wqids);
1217 	p9_client_clunk(fid);
1218 	fid = NULL;
1219 
1220 error:
1221 	if (fid && (fid != oldfid))
1222 		p9_fid_destroy(fid);
1223 
1224 	return ERR_PTR(err);
1225 }
1226 EXPORT_SYMBOL(p9_client_walk);
1227 
1228 int p9_client_open(struct p9_fid *fid, int mode)
1229 {
1230 	int err;
1231 	struct p9_client *clnt;
1232 	struct p9_req_t *req;
1233 	struct p9_qid qid;
1234 	int iounit;
1235 
1236 	clnt = fid->clnt;
1237 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1238 		p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1239 	err = 0;
1240 
1241 	if (fid->mode != -1)
1242 		return -EINVAL;
1243 
1244 	if (p9_is_proto_dotl(clnt))
1245 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode);
1246 	else
1247 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
1248 	if (IS_ERR(req)) {
1249 		err = PTR_ERR(req);
1250 		goto error;
1251 	}
1252 
1253 	err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1254 	if (err) {
1255 		trace_9p_protocol_dump(clnt, req->rc);
1256 		goto free_and_error;
1257 	}
1258 
1259 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1260 		p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1261 		(unsigned long long)qid.path, qid.version, iounit);
1262 
1263 	fid->mode = mode;
1264 	fid->iounit = iounit;
1265 
1266 free_and_error:
1267 	p9_free_req(clnt, req);
1268 error:
1269 	return err;
1270 }
1271 EXPORT_SYMBOL(p9_client_open);
1272 
1273 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags, u32 mode,
1274 		kgid_t gid, struct p9_qid *qid)
1275 {
1276 	int err = 0;
1277 	struct p9_client *clnt;
1278 	struct p9_req_t *req;
1279 	int iounit;
1280 
1281 	p9_debug(P9_DEBUG_9P,
1282 			">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1283 			ofid->fid, name, flags, mode,
1284 		 	from_kgid(&init_user_ns, gid));
1285 	clnt = ofid->clnt;
1286 
1287 	if (ofid->mode != -1)
1288 		return -EINVAL;
1289 
1290 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1291 			mode, gid);
1292 	if (IS_ERR(req)) {
1293 		err = PTR_ERR(req);
1294 		goto error;
1295 	}
1296 
1297 	err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", qid, &iounit);
1298 	if (err) {
1299 		trace_9p_protocol_dump(clnt, req->rc);
1300 		goto free_and_error;
1301 	}
1302 
1303 	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1304 			qid->type,
1305 			(unsigned long long)qid->path,
1306 			qid->version, iounit);
1307 
1308 	ofid->mode = mode;
1309 	ofid->iounit = iounit;
1310 
1311 free_and_error:
1312 	p9_free_req(clnt, req);
1313 error:
1314 	return err;
1315 }
1316 EXPORT_SYMBOL(p9_client_create_dotl);
1317 
1318 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1319 		     char *extension)
1320 {
1321 	int err;
1322 	struct p9_client *clnt;
1323 	struct p9_req_t *req;
1324 	struct p9_qid qid;
1325 	int iounit;
1326 
1327 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1328 						fid->fid, name, perm, mode);
1329 	err = 0;
1330 	clnt = fid->clnt;
1331 
1332 	if (fid->mode != -1)
1333 		return -EINVAL;
1334 
1335 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1336 				mode, extension);
1337 	if (IS_ERR(req)) {
1338 		err = PTR_ERR(req);
1339 		goto error;
1340 	}
1341 
1342 	err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1343 	if (err) {
1344 		trace_9p_protocol_dump(clnt, req->rc);
1345 		goto free_and_error;
1346 	}
1347 
1348 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1349 				qid.type,
1350 				(unsigned long long)qid.path,
1351 				qid.version, iounit);
1352 
1353 	fid->mode = mode;
1354 	fid->iounit = iounit;
1355 
1356 free_and_error:
1357 	p9_free_req(clnt, req);
1358 error:
1359 	return err;
1360 }
1361 EXPORT_SYMBOL(p9_client_fcreate);
1362 
1363 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1364 		const char *symtgt, kgid_t gid, struct p9_qid *qid)
1365 {
1366 	int err = 0;
1367 	struct p9_client *clnt;
1368 	struct p9_req_t *req;
1369 
1370 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1371 			dfid->fid, name, symtgt);
1372 	clnt = dfid->clnt;
1373 
1374 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1375 			gid);
1376 	if (IS_ERR(req)) {
1377 		err = PTR_ERR(req);
1378 		goto error;
1379 	}
1380 
1381 	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
1382 	if (err) {
1383 		trace_9p_protocol_dump(clnt, req->rc);
1384 		goto free_and_error;
1385 	}
1386 
1387 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1388 			qid->type, (unsigned long long)qid->path, qid->version);
1389 
1390 free_and_error:
1391 	p9_free_req(clnt, req);
1392 error:
1393 	return err;
1394 }
1395 EXPORT_SYMBOL(p9_client_symlink);
1396 
1397 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1398 {
1399 	struct p9_client *clnt;
1400 	struct p9_req_t *req;
1401 
1402 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1403 			dfid->fid, oldfid->fid, newname);
1404 	clnt = dfid->clnt;
1405 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1406 			newname);
1407 	if (IS_ERR(req))
1408 		return PTR_ERR(req);
1409 
1410 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1411 	p9_free_req(clnt, req);
1412 	return 0;
1413 }
1414 EXPORT_SYMBOL(p9_client_link);
1415 
1416 int p9_client_fsync(struct p9_fid *fid, int datasync)
1417 {
1418 	int err;
1419 	struct p9_client *clnt;
1420 	struct p9_req_t *req;
1421 
1422 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1423 			fid->fid, datasync);
1424 	err = 0;
1425 	clnt = fid->clnt;
1426 
1427 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1428 	if (IS_ERR(req)) {
1429 		err = PTR_ERR(req);
1430 		goto error;
1431 	}
1432 
1433 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1434 
1435 	p9_free_req(clnt, req);
1436 
1437 error:
1438 	return err;
1439 }
1440 EXPORT_SYMBOL(p9_client_fsync);
1441 
1442 int p9_client_clunk(struct p9_fid *fid)
1443 {
1444 	int err;
1445 	struct p9_client *clnt;
1446 	struct p9_req_t *req;
1447 	int retries = 0;
1448 
1449 	if (!fid) {
1450 		pr_warn("%s (%d): Trying to clunk with NULL fid\n",
1451 			__func__, task_pid_nr(current));
1452 		dump_stack();
1453 		return 0;
1454 	}
1455 
1456 again:
1457 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n", fid->fid,
1458 								retries);
1459 	err = 0;
1460 	clnt = fid->clnt;
1461 
1462 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1463 	if (IS_ERR(req)) {
1464 		err = PTR_ERR(req);
1465 		goto error;
1466 	}
1467 
1468 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1469 
1470 	p9_free_req(clnt, req);
1471 error:
1472 	/*
1473 	 * Fid is not valid even after a failed clunk
1474 	 * If interrupted, retry once then give up and
1475 	 * leak fid until umount.
1476 	 */
1477 	if (err == -ERESTARTSYS) {
1478 		if (retries++ == 0)
1479 			goto again;
1480 	} else
1481 		p9_fid_destroy(fid);
1482 	return err;
1483 }
1484 EXPORT_SYMBOL(p9_client_clunk);
1485 
1486 int p9_client_remove(struct p9_fid *fid)
1487 {
1488 	int err;
1489 	struct p9_client *clnt;
1490 	struct p9_req_t *req;
1491 
1492 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1493 	err = 0;
1494 	clnt = fid->clnt;
1495 
1496 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1497 	if (IS_ERR(req)) {
1498 		err = PTR_ERR(req);
1499 		goto error;
1500 	}
1501 
1502 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1503 
1504 	p9_free_req(clnt, req);
1505 error:
1506 	if (err == -ERESTARTSYS)
1507 		p9_client_clunk(fid);
1508 	else
1509 		p9_fid_destroy(fid);
1510 	return err;
1511 }
1512 EXPORT_SYMBOL(p9_client_remove);
1513 
1514 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1515 {
1516 	int err = 0;
1517 	struct p9_req_t *req;
1518 	struct p9_client *clnt;
1519 
1520 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1521 		   dfid->fid, name, flags);
1522 
1523 	clnt = dfid->clnt;
1524 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1525 	if (IS_ERR(req)) {
1526 		err = PTR_ERR(req);
1527 		goto error;
1528 	}
1529 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1530 
1531 	p9_free_req(clnt, req);
1532 error:
1533 	return err;
1534 }
1535 EXPORT_SYMBOL(p9_client_unlinkat);
1536 
1537 int
1538 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1539 {
1540 	struct p9_client *clnt = fid->clnt;
1541 	struct p9_req_t *req;
1542 	int total = 0;
1543 	*err = 0;
1544 
1545 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n",
1546 		   fid->fid, (unsigned long long) offset, (int)iov_iter_count(to));
1547 
1548 	while (iov_iter_count(to)) {
1549 		int count = iov_iter_count(to);
1550 		int rsize, non_zc = 0;
1551 		char *dataptr;
1552 
1553 		rsize = fid->iounit;
1554 		if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1555 			rsize = clnt->msize - P9_IOHDRSZ;
1556 
1557 		if (count < rsize)
1558 			rsize = count;
1559 
1560 		/* Don't bother zerocopy for small IO (< 1024) */
1561 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1562 			/*
1563 			 * response header len is 11
1564 			 * PDU Header(7) + IO Size (4)
1565 			 */
1566 			req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1567 					       0, 11, "dqd", fid->fid,
1568 					       offset, rsize);
1569 		} else {
1570 			non_zc = 1;
1571 			req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1572 					    rsize);
1573 		}
1574 		if (IS_ERR(req)) {
1575 			*err = PTR_ERR(req);
1576 			break;
1577 		}
1578 
1579 		*err = p9pdu_readf(req->rc, clnt->proto_version,
1580 				   "D", &count, &dataptr);
1581 		if (*err) {
1582 			trace_9p_protocol_dump(clnt, req->rc);
1583 			p9_free_req(clnt, req);
1584 			break;
1585 		}
1586 		if (rsize < count) {
1587 			pr_err("bogus RREAD count (%d > %d)\n", count, rsize);
1588 			count = rsize;
1589 		}
1590 
1591 		p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1592 		if (!count) {
1593 			p9_free_req(clnt, req);
1594 			break;
1595 		}
1596 
1597 		if (non_zc) {
1598 			int n = copy_to_iter(dataptr, count, to);
1599 			total += n;
1600 			offset += n;
1601 			if (n != count) {
1602 				*err = -EFAULT;
1603 				p9_free_req(clnt, req);
1604 				break;
1605 			}
1606 		} else {
1607 			iov_iter_advance(to, count);
1608 			total += count;
1609 			offset += count;
1610 		}
1611 		p9_free_req(clnt, req);
1612 	}
1613 	return total;
1614 }
1615 EXPORT_SYMBOL(p9_client_read);
1616 
1617 int
1618 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1619 {
1620 	struct p9_client *clnt = fid->clnt;
1621 	struct p9_req_t *req;
1622 	int total = 0;
1623 	*err = 0;
1624 
1625 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n",
1626 				fid->fid, (unsigned long long) offset,
1627 				iov_iter_count(from));
1628 
1629 	while (iov_iter_count(from)) {
1630 		int count = iov_iter_count(from);
1631 		int rsize = fid->iounit;
1632 		if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1633 			rsize = clnt->msize - P9_IOHDRSZ;
1634 
1635 		if (count < rsize)
1636 			rsize = count;
1637 
1638 		/* Don't bother zerocopy for small IO (< 1024) */
1639 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1640 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1641 					       rsize, P9_ZC_HDR_SZ, "dqd",
1642 					       fid->fid, offset, rsize);
1643 		} else {
1644 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1645 						    offset, rsize, from);
1646 		}
1647 		if (IS_ERR(req)) {
1648 			*err = PTR_ERR(req);
1649 			break;
1650 		}
1651 
1652 		*err = p9pdu_readf(req->rc, clnt->proto_version, "d", &count);
1653 		if (*err) {
1654 			trace_9p_protocol_dump(clnt, req->rc);
1655 			p9_free_req(clnt, req);
1656 			break;
1657 		}
1658 		if (rsize < count) {
1659 			pr_err("bogus RWRITE count (%d > %d)\n", count, rsize);
1660 			count = rsize;
1661 		}
1662 
1663 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1664 
1665 		p9_free_req(clnt, req);
1666 		iov_iter_advance(from, count);
1667 		total += count;
1668 		offset += count;
1669 	}
1670 	return total;
1671 }
1672 EXPORT_SYMBOL(p9_client_write);
1673 
1674 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1675 {
1676 	int err;
1677 	struct p9_client *clnt;
1678 	struct p9_wstat *ret = kmalloc(sizeof(struct p9_wstat), GFP_KERNEL);
1679 	struct p9_req_t *req;
1680 	u16 ignored;
1681 
1682 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1683 
1684 	if (!ret)
1685 		return ERR_PTR(-ENOMEM);
1686 
1687 	err = 0;
1688 	clnt = fid->clnt;
1689 
1690 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1691 	if (IS_ERR(req)) {
1692 		err = PTR_ERR(req);
1693 		goto error;
1694 	}
1695 
1696 	err = p9pdu_readf(req->rc, clnt->proto_version, "wS", &ignored, ret);
1697 	if (err) {
1698 		trace_9p_protocol_dump(clnt, req->rc);
1699 		p9_free_req(clnt, req);
1700 		goto error;
1701 	}
1702 
1703 	p9_debug(P9_DEBUG_9P,
1704 		"<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1705 		"<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1706 		"<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1707 		"<<<    uid=%d gid=%d n_muid=%d\n",
1708 		ret->size, ret->type, ret->dev, ret->qid.type,
1709 		(unsigned long long)ret->qid.path, ret->qid.version, ret->mode,
1710 		ret->atime, ret->mtime, (unsigned long long)ret->length,
1711 		ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1712 		from_kuid(&init_user_ns, ret->n_uid),
1713 		from_kgid(&init_user_ns, ret->n_gid),
1714 		from_kuid(&init_user_ns, ret->n_muid));
1715 
1716 	p9_free_req(clnt, req);
1717 	return ret;
1718 
1719 error:
1720 	kfree(ret);
1721 	return ERR_PTR(err);
1722 }
1723 EXPORT_SYMBOL(p9_client_stat);
1724 
1725 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1726 							u64 request_mask)
1727 {
1728 	int err;
1729 	struct p9_client *clnt;
1730 	struct p9_stat_dotl *ret = kmalloc(sizeof(struct p9_stat_dotl),
1731 								GFP_KERNEL);
1732 	struct p9_req_t *req;
1733 
1734 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1735 							fid->fid, request_mask);
1736 
1737 	if (!ret)
1738 		return ERR_PTR(-ENOMEM);
1739 
1740 	err = 0;
1741 	clnt = fid->clnt;
1742 
1743 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1744 	if (IS_ERR(req)) {
1745 		err = PTR_ERR(req);
1746 		goto error;
1747 	}
1748 
1749 	err = p9pdu_readf(req->rc, clnt->proto_version, "A", ret);
1750 	if (err) {
1751 		trace_9p_protocol_dump(clnt, req->rc);
1752 		p9_free_req(clnt, req);
1753 		goto error;
1754 	}
1755 
1756 	p9_debug(P9_DEBUG_9P,
1757 		"<<< RGETATTR st_result_mask=%lld\n"
1758 		"<<< qid=%x.%llx.%x\n"
1759 		"<<< st_mode=%8.8x st_nlink=%llu\n"
1760 		"<<< st_uid=%d st_gid=%d\n"
1761 		"<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1762 		"<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1763 		"<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1764 		"<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1765 		"<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1766 		"<<< st_gen=%lld st_data_version=%lld",
1767 		ret->st_result_mask, ret->qid.type, ret->qid.path,
1768 		ret->qid.version, ret->st_mode, ret->st_nlink,
1769 		from_kuid(&init_user_ns, ret->st_uid),
1770 		from_kgid(&init_user_ns, ret->st_gid),
1771 		ret->st_rdev, ret->st_size, ret->st_blksize,
1772 		ret->st_blocks, ret->st_atime_sec, ret->st_atime_nsec,
1773 		ret->st_mtime_sec, ret->st_mtime_nsec, ret->st_ctime_sec,
1774 		ret->st_ctime_nsec, ret->st_btime_sec, ret->st_btime_nsec,
1775 		ret->st_gen, ret->st_data_version);
1776 
1777 	p9_free_req(clnt, req);
1778 	return ret;
1779 
1780 error:
1781 	kfree(ret);
1782 	return ERR_PTR(err);
1783 }
1784 EXPORT_SYMBOL(p9_client_getattr_dotl);
1785 
1786 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1787 {
1788 	int ret;
1789 
1790 	/* NOTE: size shouldn't include its own length */
1791 	/* size[2] type[2] dev[4] qid[13] */
1792 	/* mode[4] atime[4] mtime[4] length[8]*/
1793 	/* name[s] uid[s] gid[s] muid[s] */
1794 	ret = 2+4+13+4+4+4+8+2+2+2+2;
1795 
1796 	if (wst->name)
1797 		ret += strlen(wst->name);
1798 	if (wst->uid)
1799 		ret += strlen(wst->uid);
1800 	if (wst->gid)
1801 		ret += strlen(wst->gid);
1802 	if (wst->muid)
1803 		ret += strlen(wst->muid);
1804 
1805 	if ((proto_version == p9_proto_2000u) ||
1806 		(proto_version == p9_proto_2000L)) {
1807 		ret += 2+4+4+4;	/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1808 		if (wst->extension)
1809 			ret += strlen(wst->extension);
1810 	}
1811 
1812 	return ret;
1813 }
1814 
1815 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1816 {
1817 	int err;
1818 	struct p9_req_t *req;
1819 	struct p9_client *clnt;
1820 
1821 	err = 0;
1822 	clnt = fid->clnt;
1823 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1824 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n", fid->fid);
1825 	p9_debug(P9_DEBUG_9P,
1826 		"     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1827 		"     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1828 		"     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1829 		"     uid=%d gid=%d n_muid=%d\n",
1830 		wst->size, wst->type, wst->dev, wst->qid.type,
1831 		(unsigned long long)wst->qid.path, wst->qid.version, wst->mode,
1832 		wst->atime, wst->mtime, (unsigned long long)wst->length,
1833 		wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1834 		from_kuid(&init_user_ns, wst->n_uid),
1835 		from_kgid(&init_user_ns, wst->n_gid),
1836 		from_kuid(&init_user_ns, wst->n_muid));
1837 
1838 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS", fid->fid, wst->size+2, wst);
1839 	if (IS_ERR(req)) {
1840 		err = PTR_ERR(req);
1841 		goto error;
1842 	}
1843 
1844 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1845 
1846 	p9_free_req(clnt, req);
1847 error:
1848 	return err;
1849 }
1850 EXPORT_SYMBOL(p9_client_wstat);
1851 
1852 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1853 {
1854 	int err;
1855 	struct p9_req_t *req;
1856 	struct p9_client *clnt;
1857 
1858 	err = 0;
1859 	clnt = fid->clnt;
1860 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1861 	p9_debug(P9_DEBUG_9P,
1862 		"    valid=%x mode=%x uid=%d gid=%d size=%lld\n"
1863 		"    atime_sec=%lld atime_nsec=%lld\n"
1864 		"    mtime_sec=%lld mtime_nsec=%lld\n",
1865 		p9attr->valid, p9attr->mode,
1866 		from_kuid(&init_user_ns, p9attr->uid),
1867 		from_kgid(&init_user_ns, p9attr->gid),
1868 		p9attr->size, p9attr->atime_sec, p9attr->atime_nsec,
1869 		p9attr->mtime_sec, p9attr->mtime_nsec);
1870 
1871 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1872 
1873 	if (IS_ERR(req)) {
1874 		err = PTR_ERR(req);
1875 		goto error;
1876 	}
1877 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1878 	p9_free_req(clnt, req);
1879 error:
1880 	return err;
1881 }
1882 EXPORT_SYMBOL(p9_client_setattr);
1883 
1884 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1885 {
1886 	int err;
1887 	struct p9_req_t *req;
1888 	struct p9_client *clnt;
1889 
1890 	err = 0;
1891 	clnt = fid->clnt;
1892 
1893 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1894 
1895 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1896 	if (IS_ERR(req)) {
1897 		err = PTR_ERR(req);
1898 		goto error;
1899 	}
1900 
1901 	err = p9pdu_readf(req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1902 		&sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1903 		&sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1904 	if (err) {
1905 		trace_9p_protocol_dump(clnt, req->rc);
1906 		p9_free_req(clnt, req);
1907 		goto error;
1908 	}
1909 
1910 	p9_debug(P9_DEBUG_9P, "<<< RSTATFS fid %d type 0x%lx bsize %ld "
1911 		"blocks %llu bfree %llu bavail %llu files %llu ffree %llu "
1912 		"fsid %llu namelen %ld\n",
1913 		fid->fid, (long unsigned int)sb->type, (long int)sb->bsize,
1914 		sb->blocks, sb->bfree, sb->bavail, sb->files,  sb->ffree,
1915 		sb->fsid, (long int)sb->namelen);
1916 
1917 	p9_free_req(clnt, req);
1918 error:
1919 	return err;
1920 }
1921 EXPORT_SYMBOL(p9_client_statfs);
1922 
1923 int p9_client_rename(struct p9_fid *fid,
1924 		     struct p9_fid *newdirfid, const char *name)
1925 {
1926 	int err;
1927 	struct p9_req_t *req;
1928 	struct p9_client *clnt;
1929 
1930 	err = 0;
1931 	clnt = fid->clnt;
1932 
1933 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1934 			fid->fid, newdirfid->fid, name);
1935 
1936 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1937 			newdirfid->fid, name);
1938 	if (IS_ERR(req)) {
1939 		err = PTR_ERR(req);
1940 		goto error;
1941 	}
1942 
1943 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1944 
1945 	p9_free_req(clnt, req);
1946 error:
1947 	return err;
1948 }
1949 EXPORT_SYMBOL(p9_client_rename);
1950 
1951 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
1952 		       struct p9_fid *newdirfid, const char *new_name)
1953 {
1954 	int err;
1955 	struct p9_req_t *req;
1956 	struct p9_client *clnt;
1957 
1958 	err = 0;
1959 	clnt = olddirfid->clnt;
1960 
1961 	p9_debug(P9_DEBUG_9P, ">>> TRENAMEAT olddirfid %d old name %s"
1962 		   " newdirfid %d new name %s\n", olddirfid->fid, old_name,
1963 		   newdirfid->fid, new_name);
1964 
1965 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
1966 			    old_name, newdirfid->fid, new_name);
1967 	if (IS_ERR(req)) {
1968 		err = PTR_ERR(req);
1969 		goto error;
1970 	}
1971 
1972 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
1973 		   newdirfid->fid, new_name);
1974 
1975 	p9_free_req(clnt, req);
1976 error:
1977 	return err;
1978 }
1979 EXPORT_SYMBOL(p9_client_renameat);
1980 
1981 /*
1982  * An xattrwalk without @attr_name gives the fid for the lisxattr namespace
1983  */
1984 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
1985 				const char *attr_name, u64 *attr_size)
1986 {
1987 	int err;
1988 	struct p9_req_t *req;
1989 	struct p9_client *clnt;
1990 	struct p9_fid *attr_fid;
1991 
1992 	err = 0;
1993 	clnt = file_fid->clnt;
1994 	attr_fid = p9_fid_create(clnt);
1995 	if (IS_ERR(attr_fid)) {
1996 		err = PTR_ERR(attr_fid);
1997 		attr_fid = NULL;
1998 		goto error;
1999 	}
2000 	p9_debug(P9_DEBUG_9P,
2001 		">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
2002 		file_fid->fid, attr_fid->fid, attr_name);
2003 
2004 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
2005 			file_fid->fid, attr_fid->fid, attr_name);
2006 	if (IS_ERR(req)) {
2007 		err = PTR_ERR(req);
2008 		goto error;
2009 	}
2010 	err = p9pdu_readf(req->rc, clnt->proto_version, "q", attr_size);
2011 	if (err) {
2012 		trace_9p_protocol_dump(clnt, req->rc);
2013 		p9_free_req(clnt, req);
2014 		goto clunk_fid;
2015 	}
2016 	p9_free_req(clnt, req);
2017 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
2018 		attr_fid->fid, *attr_size);
2019 	return attr_fid;
2020 clunk_fid:
2021 	p9_client_clunk(attr_fid);
2022 	attr_fid = NULL;
2023 error:
2024 	if (attr_fid && (attr_fid != file_fid))
2025 		p9_fid_destroy(attr_fid);
2026 
2027 	return ERR_PTR(err);
2028 }
2029 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
2030 
2031 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
2032 			u64 attr_size, int flags)
2033 {
2034 	int err;
2035 	struct p9_req_t *req;
2036 	struct p9_client *clnt;
2037 
2038 	p9_debug(P9_DEBUG_9P,
2039 		">>> TXATTRCREATE fid %d name  %s size %lld flag %d\n",
2040 		fid->fid, name, (long long)attr_size, flags);
2041 	err = 0;
2042 	clnt = fid->clnt;
2043 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
2044 			fid->fid, name, attr_size, flags);
2045 	if (IS_ERR(req)) {
2046 		err = PTR_ERR(req);
2047 		goto error;
2048 	}
2049 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
2050 	p9_free_req(clnt, req);
2051 error:
2052 	return err;
2053 }
2054 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
2055 
2056 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
2057 {
2058 	int err, rsize, non_zc = 0;
2059 	struct p9_client *clnt;
2060 	struct p9_req_t *req;
2061 	char *dataptr;
2062 	struct kvec kv = {.iov_base = data, .iov_len = count};
2063 	struct iov_iter to;
2064 
2065 	iov_iter_kvec(&to, READ | ITER_KVEC, &kv, 1, count);
2066 
2067 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
2068 				fid->fid, (unsigned long long) offset, count);
2069 
2070 	err = 0;
2071 	clnt = fid->clnt;
2072 
2073 	rsize = fid->iounit;
2074 	if (!rsize || rsize > clnt->msize-P9_READDIRHDRSZ)
2075 		rsize = clnt->msize - P9_READDIRHDRSZ;
2076 
2077 	if (count < rsize)
2078 		rsize = count;
2079 
2080 	/* Don't bother zerocopy for small IO (< 1024) */
2081 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2082 		/*
2083 		 * response header len is 11
2084 		 * PDU Header(7) + IO Size (4)
2085 		 */
2086 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2087 				       11, "dqd", fid->fid, offset, rsize);
2088 	} else {
2089 		non_zc = 1;
2090 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2091 				    offset, rsize);
2092 	}
2093 	if (IS_ERR(req)) {
2094 		err = PTR_ERR(req);
2095 		goto error;
2096 	}
2097 
2098 	err = p9pdu_readf(req->rc, clnt->proto_version, "D", &count, &dataptr);
2099 	if (err) {
2100 		trace_9p_protocol_dump(clnt, req->rc);
2101 		goto free_and_error;
2102 	}
2103 	if (rsize < count) {
2104 		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
2105 		count = rsize;
2106 	}
2107 
2108 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
2109 
2110 	if (non_zc)
2111 		memmove(data, dataptr, count);
2112 
2113 	p9_free_req(clnt, req);
2114 	return count;
2115 
2116 free_and_error:
2117 	p9_free_req(clnt, req);
2118 error:
2119 	return err;
2120 }
2121 EXPORT_SYMBOL(p9_client_readdir);
2122 
2123 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2124 			dev_t rdev, kgid_t gid, struct p9_qid *qid)
2125 {
2126 	int err;
2127 	struct p9_client *clnt;
2128 	struct p9_req_t *req;
2129 
2130 	err = 0;
2131 	clnt = fid->clnt;
2132 	p9_debug(P9_DEBUG_9P, ">>> TMKNOD fid %d name %s mode %d major %d "
2133 		"minor %d\n", fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2134 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2135 		MAJOR(rdev), MINOR(rdev), gid);
2136 	if (IS_ERR(req))
2137 		return PTR_ERR(req);
2138 
2139 	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
2140 	if (err) {
2141 		trace_9p_protocol_dump(clnt, req->rc);
2142 		goto error;
2143 	}
2144 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n", qid->type,
2145 				(unsigned long long)qid->path, qid->version);
2146 
2147 error:
2148 	p9_free_req(clnt, req);
2149 	return err;
2150 
2151 }
2152 EXPORT_SYMBOL(p9_client_mknod_dotl);
2153 
2154 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2155 				kgid_t gid, struct p9_qid *qid)
2156 {
2157 	int err;
2158 	struct p9_client *clnt;
2159 	struct p9_req_t *req;
2160 
2161 	err = 0;
2162 	clnt = fid->clnt;
2163 	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
2164 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
2165 	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg", fid->fid, name, mode,
2166 		gid);
2167 	if (IS_ERR(req))
2168 		return PTR_ERR(req);
2169 
2170 	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
2171 	if (err) {
2172 		trace_9p_protocol_dump(clnt, req->rc);
2173 		goto error;
2174 	}
2175 	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
2176 				(unsigned long long)qid->path, qid->version);
2177 
2178 error:
2179 	p9_free_req(clnt, req);
2180 	return err;
2181 
2182 }
2183 EXPORT_SYMBOL(p9_client_mkdir_dotl);
2184 
2185 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
2186 {
2187 	int err;
2188 	struct p9_client *clnt;
2189 	struct p9_req_t *req;
2190 
2191 	err = 0;
2192 	clnt = fid->clnt;
2193 	p9_debug(P9_DEBUG_9P, ">>> TLOCK fid %d type %i flags %d "
2194 			"start %lld length %lld proc_id %d client_id %s\n",
2195 			fid->fid, flock->type, flock->flags, flock->start,
2196 			flock->length, flock->proc_id, flock->client_id);
2197 
2198 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2199 				flock->flags, flock->start, flock->length,
2200 					flock->proc_id, flock->client_id);
2201 
2202 	if (IS_ERR(req))
2203 		return PTR_ERR(req);
2204 
2205 	err = p9pdu_readf(req->rc, clnt->proto_version, "b", status);
2206 	if (err) {
2207 		trace_9p_protocol_dump(clnt, req->rc);
2208 		goto error;
2209 	}
2210 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2211 error:
2212 	p9_free_req(clnt, req);
2213 	return err;
2214 
2215 }
2216 EXPORT_SYMBOL(p9_client_lock_dotl);
2217 
2218 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2219 {
2220 	int err;
2221 	struct p9_client *clnt;
2222 	struct p9_req_t *req;
2223 
2224 	err = 0;
2225 	clnt = fid->clnt;
2226 	p9_debug(P9_DEBUG_9P, ">>> TGETLOCK fid %d, type %i start %lld "
2227 		"length %lld proc_id %d client_id %s\n", fid->fid, glock->type,
2228 		glock->start, glock->length, glock->proc_id, glock->client_id);
2229 
2230 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,  glock->type,
2231 		glock->start, glock->length, glock->proc_id, glock->client_id);
2232 
2233 	if (IS_ERR(req))
2234 		return PTR_ERR(req);
2235 
2236 	err = p9pdu_readf(req->rc, clnt->proto_version, "bqqds", &glock->type,
2237 			&glock->start, &glock->length, &glock->proc_id,
2238 			&glock->client_id);
2239 	if (err) {
2240 		trace_9p_protocol_dump(clnt, req->rc);
2241 		goto error;
2242 	}
2243 	p9_debug(P9_DEBUG_9P, "<<< RGETLOCK type %i start %lld length %lld "
2244 		"proc_id %d client_id %s\n", glock->type, glock->start,
2245 		glock->length, glock->proc_id, glock->client_id);
2246 error:
2247 	p9_free_req(clnt, req);
2248 	return err;
2249 }
2250 EXPORT_SYMBOL(p9_client_getlock_dotl);
2251 
2252 int p9_client_readlink(struct p9_fid *fid, char **target)
2253 {
2254 	int err;
2255 	struct p9_client *clnt;
2256 	struct p9_req_t *req;
2257 
2258 	err = 0;
2259 	clnt = fid->clnt;
2260 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2261 
2262 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2263 	if (IS_ERR(req))
2264 		return PTR_ERR(req);
2265 
2266 	err = p9pdu_readf(req->rc, clnt->proto_version, "s", target);
2267 	if (err) {
2268 		trace_9p_protocol_dump(clnt, req->rc);
2269 		goto error;
2270 	}
2271 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2272 error:
2273 	p9_free_req(clnt, req);
2274 	return err;
2275 }
2276 EXPORT_SYMBOL(p9_client_readlink);
2277