xref: /linux/net/9p/client.c (revision e21f9e2e862e9eb3dd64eaddb6256b3e5098660f)
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 <linux/seq_file.h>
41 #include <net/9p/client.h>
42 #include <net/9p/transport.h>
43 #include "protocol.h"
44 
45 #define CREATE_TRACE_POINTS
46 #include <trace/events/9p.h>
47 
48 /*
49   * Client Option Parsing (code inspired by NFS code)
50   *  - a little lazy - parse all client options
51   */
52 
53 enum {
54 	Opt_msize,
55 	Opt_trans,
56 	Opt_legacy,
57 	Opt_version,
58 	Opt_err,
59 };
60 
61 static const match_table_t tokens = {
62 	{Opt_msize, "msize=%u"},
63 	{Opt_legacy, "noextend"},
64 	{Opt_trans, "trans=%s"},
65 	{Opt_version, "version=%s"},
66 	{Opt_err, NULL},
67 };
68 
69 inline int p9_is_proto_dotl(struct p9_client *clnt)
70 {
71 	return clnt->proto_version == p9_proto_2000L;
72 }
73 EXPORT_SYMBOL(p9_is_proto_dotl);
74 
75 inline int p9_is_proto_dotu(struct p9_client *clnt)
76 {
77 	return clnt->proto_version == p9_proto_2000u;
78 }
79 EXPORT_SYMBOL(p9_is_proto_dotu);
80 
81 int p9_show_client_options(struct seq_file *m, struct p9_client *clnt)
82 {
83 	if (clnt->msize != 8192)
84 		seq_printf(m, ",msize=%u", clnt->msize);
85 	seq_printf(m, ",trans=%s", clnt->trans_mod->name);
86 
87 	switch (clnt->proto_version) {
88 	case p9_proto_legacy:
89 		seq_puts(m, ",noextend");
90 		break;
91 	case p9_proto_2000u:
92 		seq_puts(m, ",version=9p2000.u");
93 		break;
94 	case p9_proto_2000L:
95 		/* Default */
96 		break;
97 	}
98 
99 	if (clnt->trans_mod->show_options)
100 		return clnt->trans_mod->show_options(m, clnt);
101 	return 0;
102 }
103 EXPORT_SYMBOL(p9_show_client_options);
104 
105 /*
106  * Some error codes are taken directly from the server replies,
107  * make sure they are valid.
108  */
109 static int safe_errno(int err)
110 {
111 	if ((err > 0) || (err < -MAX_ERRNO)) {
112 		p9_debug(P9_DEBUG_ERROR, "Invalid error code %d\n", err);
113 		return -EPROTO;
114 	}
115 	return err;
116 }
117 
118 
119 /* Interpret mount option for protocol version */
120 static int get_protocol_version(char *s)
121 {
122 	int version = -EINVAL;
123 
124 	if (!strcmp(s, "9p2000")) {
125 		version = p9_proto_legacy;
126 		p9_debug(P9_DEBUG_9P, "Protocol version: Legacy\n");
127 	} else if (!strcmp(s, "9p2000.u")) {
128 		version = p9_proto_2000u;
129 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.u\n");
130 	} else if (!strcmp(s, "9p2000.L")) {
131 		version = p9_proto_2000L;
132 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.L\n");
133 	} else
134 		pr_info("Unknown protocol version %s\n", s);
135 
136 	return version;
137 }
138 
139 /**
140  * parse_options - parse mount options into client structure
141  * @opts: options string passed from mount
142  * @clnt: existing v9fs client information
143  *
144  * Return 0 upon success, -ERRNO upon failure
145  */
146 
147 static int parse_opts(char *opts, struct p9_client *clnt)
148 {
149 	char *options, *tmp_options;
150 	char *p;
151 	substring_t args[MAX_OPT_ARGS];
152 	int option;
153 	char *s;
154 	int ret = 0;
155 
156 	clnt->proto_version = p9_proto_2000L;
157 	clnt->msize = 8192;
158 
159 	if (!opts)
160 		return 0;
161 
162 	tmp_options = kstrdup(opts, GFP_KERNEL);
163 	if (!tmp_options) {
164 		p9_debug(P9_DEBUG_ERROR,
165 			 "failed to allocate copy of option string\n");
166 		return -ENOMEM;
167 	}
168 	options = tmp_options;
169 
170 	while ((p = strsep(&options, ",")) != NULL) {
171 		int token, r;
172 		if (!*p)
173 			continue;
174 		token = match_token(p, tokens, args);
175 		switch (token) {
176 		case Opt_msize:
177 			r = match_int(&args[0], &option);
178 			if (r < 0) {
179 				p9_debug(P9_DEBUG_ERROR,
180 					 "integer field, but no integer?\n");
181 				ret = r;
182 				continue;
183 			}
184 			clnt->msize = option;
185 			break;
186 		case Opt_trans:
187 			s = match_strdup(&args[0]);
188 			if (!s) {
189 				ret = -ENOMEM;
190 				p9_debug(P9_DEBUG_ERROR,
191 					 "problem allocating copy of trans arg\n");
192 				goto free_and_return;
193 			}
194 
195 			v9fs_put_trans(clnt->trans_mod);
196 			clnt->trans_mod = v9fs_get_trans_by_name(s);
197 			if (clnt->trans_mod == NULL) {
198 				pr_info("Could not find request transport: %s\n",
199 					s);
200 				ret = -EINVAL;
201 				kfree(s);
202 				goto free_and_return;
203 			}
204 			kfree(s);
205 			break;
206 		case Opt_legacy:
207 			clnt->proto_version = p9_proto_legacy;
208 			break;
209 		case Opt_version:
210 			s = match_strdup(&args[0]);
211 			if (!s) {
212 				ret = -ENOMEM;
213 				p9_debug(P9_DEBUG_ERROR,
214 					 "problem allocating copy of version arg\n");
215 				goto free_and_return;
216 			}
217 			ret = get_protocol_version(s);
218 			if (ret == -EINVAL) {
219 				kfree(s);
220 				goto free_and_return;
221 			}
222 			kfree(s);
223 			clnt->proto_version = ret;
224 			break;
225 		default:
226 			continue;
227 		}
228 	}
229 
230 free_and_return:
231 	v9fs_put_trans(clnt->trans_mod);
232 	kfree(tmp_options);
233 	return ret;
234 }
235 
236 static struct p9_fcall *p9_fcall_alloc(int alloc_msize)
237 {
238 	struct p9_fcall *fc;
239 	fc = kmalloc(sizeof(struct p9_fcall) + alloc_msize, GFP_NOFS);
240 	if (!fc)
241 		return NULL;
242 	fc->capacity = alloc_msize;
243 	fc->sdata = (char *) fc + sizeof(struct p9_fcall);
244 	return fc;
245 }
246 
247 /**
248  * p9_tag_alloc - lookup/allocate a request by tag
249  * @c: client session to lookup tag within
250  * @tag: numeric id for transaction
251  *
252  * this is a simple array lookup, but will grow the
253  * request_slots as necessary to accommodate transaction
254  * ids which did not previously have a slot.
255  *
256  * this code relies on the client spinlock to manage locks, its
257  * possible we should switch to something else, but I'd rather
258  * stick with something low-overhead for the common case.
259  *
260  */
261 
262 static struct p9_req_t *
263 p9_tag_alloc(struct p9_client *c, u16 tag, unsigned int max_size)
264 {
265 	unsigned long flags;
266 	int row, col;
267 	struct p9_req_t *req;
268 	int alloc_msize = min(c->msize, max_size);
269 
270 	/* This looks up the original request by tag so we know which
271 	 * buffer to read the data into */
272 	tag++;
273 
274 	if (tag >= c->max_tag) {
275 		spin_lock_irqsave(&c->lock, flags);
276 		/* check again since original check was outside of lock */
277 		while (tag >= c->max_tag) {
278 			row = (tag / P9_ROW_MAXTAG);
279 			c->reqs[row] = kcalloc(P9_ROW_MAXTAG,
280 					sizeof(struct p9_req_t), GFP_ATOMIC);
281 
282 			if (!c->reqs[row]) {
283 				pr_err("Couldn't grow tag array\n");
284 				spin_unlock_irqrestore(&c->lock, flags);
285 				return ERR_PTR(-ENOMEM);
286 			}
287 			for (col = 0; col < P9_ROW_MAXTAG; col++) {
288 				c->reqs[row][col].status = REQ_STATUS_IDLE;
289 				c->reqs[row][col].tc = NULL;
290 			}
291 			c->max_tag += P9_ROW_MAXTAG;
292 		}
293 		spin_unlock_irqrestore(&c->lock, flags);
294 	}
295 	row = tag / P9_ROW_MAXTAG;
296 	col = tag % P9_ROW_MAXTAG;
297 
298 	req = &c->reqs[row][col];
299 	if (!req->wq) {
300 		req->wq = kmalloc(sizeof(wait_queue_head_t), GFP_NOFS);
301 		if (!req->wq)
302 			goto grow_failed;
303 		init_waitqueue_head(req->wq);
304 	}
305 
306 	if (!req->tc)
307 		req->tc = p9_fcall_alloc(alloc_msize);
308 	if (!req->rc)
309 		req->rc = p9_fcall_alloc(alloc_msize);
310 	if (!req->tc || !req->rc)
311 		goto grow_failed;
312 
313 	p9pdu_reset(req->tc);
314 	p9pdu_reset(req->rc);
315 
316 	req->tc->tag = tag-1;
317 	req->status = REQ_STATUS_ALLOC;
318 
319 	return req;
320 
321 grow_failed:
322 	pr_err("Couldn't grow tag array\n");
323 	kfree(req->tc);
324 	kfree(req->rc);
325 	kfree(req->wq);
326 	req->tc = req->rc = NULL;
327 	req->wq = NULL;
328 	return ERR_PTR(-ENOMEM);
329 }
330 
331 /**
332  * p9_tag_lookup - lookup a request by tag
333  * @c: client session to lookup tag within
334  * @tag: numeric id for transaction
335  *
336  */
337 
338 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
339 {
340 	int row, col;
341 
342 	/* This looks up the original request by tag so we know which
343 	 * buffer to read the data into */
344 	tag++;
345 
346 	if(tag >= c->max_tag)
347 		return NULL;
348 
349 	row = tag / P9_ROW_MAXTAG;
350 	col = tag % P9_ROW_MAXTAG;
351 
352 	return &c->reqs[row][col];
353 }
354 EXPORT_SYMBOL(p9_tag_lookup);
355 
356 /**
357  * p9_tag_init - setup tags structure and contents
358  * @c:  v9fs client struct
359  *
360  * This initializes the tags structure for each client instance.
361  *
362  */
363 
364 static int p9_tag_init(struct p9_client *c)
365 {
366 	int err = 0;
367 
368 	c->tagpool = p9_idpool_create();
369 	if (IS_ERR(c->tagpool)) {
370 		err = PTR_ERR(c->tagpool);
371 		goto error;
372 	}
373 	err = p9_idpool_get(c->tagpool); /* reserve tag 0 */
374 	if (err < 0) {
375 		p9_idpool_destroy(c->tagpool);
376 		goto error;
377 	}
378 	c->max_tag = 0;
379 error:
380 	return err;
381 }
382 
383 /**
384  * p9_tag_cleanup - cleans up tags structure and reclaims resources
385  * @c:  v9fs client struct
386  *
387  * This frees resources associated with the tags structure
388  *
389  */
390 static void p9_tag_cleanup(struct p9_client *c)
391 {
392 	int row, col;
393 
394 	/* check to insure all requests are idle */
395 	for (row = 0; row < (c->max_tag/P9_ROW_MAXTAG); row++) {
396 		for (col = 0; col < P9_ROW_MAXTAG; col++) {
397 			if (c->reqs[row][col].status != REQ_STATUS_IDLE) {
398 				p9_debug(P9_DEBUG_MUX,
399 					 "Attempting to cleanup non-free tag %d,%d\n",
400 					 row, col);
401 				/* TODO: delay execution of cleanup */
402 				return;
403 			}
404 		}
405 	}
406 
407 	if (c->tagpool) {
408 		p9_idpool_put(0, c->tagpool); /* free reserved tag 0 */
409 		p9_idpool_destroy(c->tagpool);
410 	}
411 
412 	/* free requests associated with tags */
413 	for (row = 0; row < (c->max_tag/P9_ROW_MAXTAG); row++) {
414 		for (col = 0; col < P9_ROW_MAXTAG; col++) {
415 			kfree(c->reqs[row][col].wq);
416 			kfree(c->reqs[row][col].tc);
417 			kfree(c->reqs[row][col].rc);
418 		}
419 		kfree(c->reqs[row]);
420 	}
421 	c->max_tag = 0;
422 }
423 
424 /**
425  * p9_free_req - free a request and clean-up as necessary
426  * c: client state
427  * r: request to release
428  *
429  */
430 
431 static void p9_free_req(struct p9_client *c, struct p9_req_t *r)
432 {
433 	int tag = r->tc->tag;
434 	p9_debug(P9_DEBUG_MUX, "clnt %p req %p tag: %d\n", c, r, tag);
435 
436 	r->status = REQ_STATUS_IDLE;
437 	if (tag != P9_NOTAG && p9_idpool_check(tag, c->tagpool))
438 		p9_idpool_put(tag, c->tagpool);
439 }
440 
441 /**
442  * p9_client_cb - call back from transport to client
443  * c: client state
444  * req: request received
445  *
446  */
447 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
448 {
449 	p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc->tag);
450 
451 	/*
452 	 * This barrier is needed to make sure any change made to req before
453 	 * the other thread wakes up will indeed be seen by the waiting side.
454 	 */
455 	smp_wmb();
456 	req->status = status;
457 
458 	wake_up(req->wq);
459 	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc->tag);
460 }
461 EXPORT_SYMBOL(p9_client_cb);
462 
463 /**
464  * p9_parse_header - parse header arguments out of a packet
465  * @pdu: packet to parse
466  * @size: size of packet
467  * @type: type of request
468  * @tag: tag of packet
469  * @rewind: set if we need to rewind offset afterwards
470  */
471 
472 int
473 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type, int16_t *tag,
474 								int rewind)
475 {
476 	int8_t r_type;
477 	int16_t r_tag;
478 	int32_t r_size;
479 	int offset = pdu->offset;
480 	int err;
481 
482 	pdu->offset = 0;
483 	if (pdu->size == 0)
484 		pdu->size = 7;
485 
486 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
487 	if (err)
488 		goto rewind_and_exit;
489 
490 	pdu->size = r_size;
491 	pdu->id = r_type;
492 	pdu->tag = r_tag;
493 
494 	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
495 		 pdu->size, pdu->id, pdu->tag);
496 
497 	if (type)
498 		*type = r_type;
499 	if (tag)
500 		*tag = r_tag;
501 	if (size)
502 		*size = r_size;
503 
504 
505 rewind_and_exit:
506 	if (rewind)
507 		pdu->offset = offset;
508 	return err;
509 }
510 EXPORT_SYMBOL(p9_parse_header);
511 
512 /**
513  * p9_check_errors - check 9p packet for error return and process it
514  * @c: current client instance
515  * @req: request to parse and check for error conditions
516  *
517  * returns error code if one is discovered, otherwise returns 0
518  *
519  * this will have to be more complicated if we have multiple
520  * error packet types
521  */
522 
523 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
524 {
525 	int8_t type;
526 	int err;
527 	int ecode;
528 
529 	err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
530 	/*
531 	 * dump the response from server
532 	 * This should be after check errors which poplulate pdu_fcall.
533 	 */
534 	trace_9p_protocol_dump(c, req->rc);
535 	if (err) {
536 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
537 		return err;
538 	}
539 	if (type != P9_RERROR && type != P9_RLERROR)
540 		return 0;
541 
542 	if (!p9_is_proto_dotl(c)) {
543 		char *ename;
544 		err = p9pdu_readf(req->rc, c->proto_version, "s?d",
545 				  &ename, &ecode);
546 		if (err)
547 			goto out_err;
548 
549 		if (p9_is_proto_dotu(c) && ecode < 512)
550 			err = -ecode;
551 
552 		if (!err) {
553 			err = p9_errstr2errno(ename, strlen(ename));
554 
555 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
556 				 -ecode, ename);
557 		}
558 		kfree(ename);
559 	} else {
560 		err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode);
561 		err = -ecode;
562 
563 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
564 	}
565 
566 	return err;
567 
568 out_err:
569 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
570 
571 	return err;
572 }
573 
574 /**
575  * p9_check_zc_errors - check 9p packet for error return and process it
576  * @c: current client instance
577  * @req: request to parse and check for error conditions
578  * @in_hdrlen: Size of response protocol buffer.
579  *
580  * returns error code if one is discovered, otherwise returns 0
581  *
582  * this will have to be more complicated if we have multiple
583  * error packet types
584  */
585 
586 static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
587 			      struct iov_iter *uidata, int in_hdrlen)
588 {
589 	int err;
590 	int ecode;
591 	int8_t type;
592 	char *ename = NULL;
593 
594 	err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
595 	/*
596 	 * dump the response from server
597 	 * This should be after parse_header which poplulate pdu_fcall.
598 	 */
599 	trace_9p_protocol_dump(c, req->rc);
600 	if (err) {
601 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
602 		return err;
603 	}
604 
605 	if (type != P9_RERROR && type != P9_RLERROR)
606 		return 0;
607 
608 	if (!p9_is_proto_dotl(c)) {
609 		/* Error is reported in string format */
610 		int len;
611 		/* 7 = header size for RERROR; */
612 		int inline_len = in_hdrlen - 7;
613 
614 		len =  req->rc->size - req->rc->offset;
615 		if (len > (P9_ZC_HDR_SZ - 7)) {
616 			err = -EFAULT;
617 			goto out_err;
618 		}
619 
620 		ename = &req->rc->sdata[req->rc->offset];
621 		if (len > inline_len) {
622 			/* We have error in external buffer */
623 			if (!copy_from_iter_full(ename + inline_len,
624 					     len - inline_len, uidata)) {
625 				err = -EFAULT;
626 				goto out_err;
627 			}
628 		}
629 		ename = NULL;
630 		err = p9pdu_readf(req->rc, c->proto_version, "s?d",
631 				  &ename, &ecode);
632 		if (err)
633 			goto out_err;
634 
635 		if (p9_is_proto_dotu(c) && ecode < 512)
636 			err = -ecode;
637 
638 		if (!err) {
639 			err = p9_errstr2errno(ename, strlen(ename));
640 
641 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
642 				 -ecode, ename);
643 		}
644 		kfree(ename);
645 	} else {
646 		err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode);
647 		err = -ecode;
648 
649 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
650 	}
651 	return err;
652 
653 out_err:
654 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
655 	return err;
656 }
657 
658 static struct p9_req_t *
659 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
660 
661 /**
662  * p9_client_flush - flush (cancel) a request
663  * @c: client state
664  * @oldreq: request to cancel
665  *
666  * This sents a flush for a particular request and links
667  * the flush request to the original request.  The current
668  * code only supports a single flush request although the protocol
669  * allows for multiple flush requests to be sent for a single request.
670  *
671  */
672 
673 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
674 {
675 	struct p9_req_t *req;
676 	int16_t oldtag;
677 	int err;
678 
679 	err = p9_parse_header(oldreq->tc, NULL, NULL, &oldtag, 1);
680 	if (err)
681 		return err;
682 
683 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
684 
685 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
686 	if (IS_ERR(req))
687 		return PTR_ERR(req);
688 
689 	/*
690 	 * if we haven't received a response for oldreq,
691 	 * remove it from the list
692 	 */
693 	if (oldreq->status == REQ_STATUS_SENT)
694 		if (c->trans_mod->cancelled)
695 			c->trans_mod->cancelled(c, oldreq);
696 
697 	p9_free_req(c, req);
698 	return 0;
699 }
700 
701 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
702 					      int8_t type, int req_size,
703 					      const char *fmt, va_list ap)
704 {
705 	int tag, err;
706 	struct p9_req_t *req;
707 
708 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
709 
710 	/* we allow for any status other than disconnected */
711 	if (c->status == Disconnected)
712 		return ERR_PTR(-EIO);
713 
714 	/* if status is begin_disconnected we allow only clunk request */
715 	if ((c->status == BeginDisconnect) && (type != P9_TCLUNK))
716 		return ERR_PTR(-EIO);
717 
718 	tag = P9_NOTAG;
719 	if (type != P9_TVERSION) {
720 		tag = p9_idpool_get(c->tagpool);
721 		if (tag < 0)
722 			return ERR_PTR(-ENOMEM);
723 	}
724 
725 	req = p9_tag_alloc(c, tag, req_size);
726 	if (IS_ERR(req))
727 		return req;
728 
729 	/* marshall the data */
730 	p9pdu_prepare(req->tc, tag, type);
731 	err = p9pdu_vwritef(req->tc, c->proto_version, fmt, ap);
732 	if (err)
733 		goto reterr;
734 	p9pdu_finalize(c, req->tc);
735 	trace_9p_client_req(c, type, tag);
736 	return req;
737 reterr:
738 	p9_free_req(c, req);
739 	return ERR_PTR(err);
740 }
741 
742 /**
743  * p9_client_rpc - issue a request and wait for a response
744  * @c: client session
745  * @type: type of request
746  * @fmt: protocol format string (see protocol.c)
747  *
748  * Returns request structure (which client must free using p9_free_req)
749  */
750 
751 static struct p9_req_t *
752 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
753 {
754 	va_list ap;
755 	int sigpending, err;
756 	unsigned long flags;
757 	struct p9_req_t *req;
758 
759 	va_start(ap, fmt);
760 	req = p9_client_prepare_req(c, type, c->msize, fmt, ap);
761 	va_end(ap);
762 	if (IS_ERR(req))
763 		return req;
764 
765 	if (signal_pending(current)) {
766 		sigpending = 1;
767 		clear_thread_flag(TIF_SIGPENDING);
768 	} else
769 		sigpending = 0;
770 
771 	err = c->trans_mod->request(c, req);
772 	if (err < 0) {
773 		if (err != -ERESTARTSYS && err != -EFAULT)
774 			c->status = Disconnected;
775 		goto recalc_sigpending;
776 	}
777 again:
778 	/* Wait for the response */
779 	err = wait_event_killable(*req->wq, req->status >= REQ_STATUS_RCVD);
780 
781 	/*
782 	 * Make sure our req is coherent with regard to updates in other
783 	 * threads - echoes to wmb() in the callback
784 	 */
785 	smp_rmb();
786 
787 	if ((err == -ERESTARTSYS) && (c->status == Connected)
788 				  && (type == P9_TFLUSH)) {
789 		sigpending = 1;
790 		clear_thread_flag(TIF_SIGPENDING);
791 		goto again;
792 	}
793 
794 	if (req->status == REQ_STATUS_ERROR) {
795 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
796 		err = req->t_err;
797 	}
798 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
799 		p9_debug(P9_DEBUG_MUX, "flushing\n");
800 		sigpending = 1;
801 		clear_thread_flag(TIF_SIGPENDING);
802 
803 		if (c->trans_mod->cancel(c, req))
804 			p9_client_flush(c, req);
805 
806 		/* if we received the response anyway, don't signal error */
807 		if (req->status == REQ_STATUS_RCVD)
808 			err = 0;
809 	}
810 recalc_sigpending:
811 	if (sigpending) {
812 		spin_lock_irqsave(&current->sighand->siglock, flags);
813 		recalc_sigpending();
814 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
815 	}
816 	if (err < 0)
817 		goto reterr;
818 
819 	err = p9_check_errors(c, req);
820 	trace_9p_client_res(c, type, req->rc->tag, err);
821 	if (!err)
822 		return req;
823 reterr:
824 	p9_free_req(c, req);
825 	return ERR_PTR(safe_errno(err));
826 }
827 
828 /**
829  * p9_client_zc_rpc - issue a request and wait for a response
830  * @c: client session
831  * @type: type of request
832  * @uidata: destination for zero copy read
833  * @uodata: source for zero copy write
834  * @inlen: read buffer size
835  * @olen: write buffer size
836  * @hdrlen: reader header size, This is the size of response protocol data
837  * @fmt: protocol format string (see protocol.c)
838  *
839  * Returns request structure (which client must free using p9_free_req)
840  */
841 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
842 					 struct iov_iter *uidata,
843 					 struct iov_iter *uodata,
844 					 int inlen, int olen, int in_hdrlen,
845 					 const char *fmt, ...)
846 {
847 	va_list ap;
848 	int sigpending, err;
849 	unsigned long flags;
850 	struct p9_req_t *req;
851 
852 	va_start(ap, fmt);
853 	/*
854 	 * We allocate a inline protocol data of only 4k bytes.
855 	 * The actual content is passed in zero-copy fashion.
856 	 */
857 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, fmt, ap);
858 	va_end(ap);
859 	if (IS_ERR(req))
860 		return req;
861 
862 	if (signal_pending(current)) {
863 		sigpending = 1;
864 		clear_thread_flag(TIF_SIGPENDING);
865 	} else
866 		sigpending = 0;
867 
868 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
869 				       inlen, olen, in_hdrlen);
870 	if (err < 0) {
871 		if (err == -EIO)
872 			c->status = Disconnected;
873 		if (err != -ERESTARTSYS)
874 			goto recalc_sigpending;
875 	}
876 	if (req->status == REQ_STATUS_ERROR) {
877 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
878 		err = req->t_err;
879 	}
880 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
881 		p9_debug(P9_DEBUG_MUX, "flushing\n");
882 		sigpending = 1;
883 		clear_thread_flag(TIF_SIGPENDING);
884 
885 		if (c->trans_mod->cancel(c, req))
886 			p9_client_flush(c, req);
887 
888 		/* if we received the response anyway, don't signal error */
889 		if (req->status == REQ_STATUS_RCVD)
890 			err = 0;
891 	}
892 recalc_sigpending:
893 	if (sigpending) {
894 		spin_lock_irqsave(&current->sighand->siglock, flags);
895 		recalc_sigpending();
896 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
897 	}
898 	if (err < 0)
899 		goto reterr;
900 
901 	err = p9_check_zc_errors(c, req, uidata, in_hdrlen);
902 	trace_9p_client_res(c, type, req->rc->tag, err);
903 	if (!err)
904 		return req;
905 reterr:
906 	p9_free_req(c, req);
907 	return ERR_PTR(safe_errno(err));
908 }
909 
910 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
911 {
912 	int ret;
913 	struct p9_fid *fid;
914 	unsigned long flags;
915 
916 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
917 	fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
918 	if (!fid)
919 		return ERR_PTR(-ENOMEM);
920 
921 	ret = p9_idpool_get(clnt->fidpool);
922 	if (ret < 0) {
923 		ret = -ENOSPC;
924 		goto error;
925 	}
926 	fid->fid = ret;
927 
928 	memset(&fid->qid, 0, sizeof(struct p9_qid));
929 	fid->mode = -1;
930 	fid->uid = current_fsuid();
931 	fid->clnt = clnt;
932 	fid->rdir = NULL;
933 	spin_lock_irqsave(&clnt->lock, flags);
934 	list_add(&fid->flist, &clnt->fidlist);
935 	spin_unlock_irqrestore(&clnt->lock, flags);
936 
937 	return fid;
938 
939 error:
940 	kfree(fid);
941 	return ERR_PTR(ret);
942 }
943 
944 static void p9_fid_destroy(struct p9_fid *fid)
945 {
946 	struct p9_client *clnt;
947 	unsigned long flags;
948 
949 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
950 	clnt = fid->clnt;
951 	p9_idpool_put(fid->fid, clnt->fidpool);
952 	spin_lock_irqsave(&clnt->lock, flags);
953 	list_del(&fid->flist);
954 	spin_unlock_irqrestore(&clnt->lock, flags);
955 	kfree(fid->rdir);
956 	kfree(fid);
957 }
958 
959 static int p9_client_version(struct p9_client *c)
960 {
961 	int err = 0;
962 	struct p9_req_t *req;
963 	char *version;
964 	int msize;
965 
966 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
967 		 c->msize, c->proto_version);
968 
969 	switch (c->proto_version) {
970 	case p9_proto_2000L:
971 		req = p9_client_rpc(c, P9_TVERSION, "ds",
972 					c->msize, "9P2000.L");
973 		break;
974 	case p9_proto_2000u:
975 		req = p9_client_rpc(c, P9_TVERSION, "ds",
976 					c->msize, "9P2000.u");
977 		break;
978 	case p9_proto_legacy:
979 		req = p9_client_rpc(c, P9_TVERSION, "ds",
980 					c->msize, "9P2000");
981 		break;
982 	default:
983 		return -EINVAL;
984 	}
985 
986 	if (IS_ERR(req))
987 		return PTR_ERR(req);
988 
989 	err = p9pdu_readf(req->rc, c->proto_version, "ds", &msize, &version);
990 	if (err) {
991 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
992 		trace_9p_protocol_dump(c, req->rc);
993 		goto error;
994 	}
995 
996 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
997 	if (!strncmp(version, "9P2000.L", 8))
998 		c->proto_version = p9_proto_2000L;
999 	else if (!strncmp(version, "9P2000.u", 8))
1000 		c->proto_version = p9_proto_2000u;
1001 	else if (!strncmp(version, "9P2000", 6))
1002 		c->proto_version = p9_proto_legacy;
1003 	else {
1004 		err = -EREMOTEIO;
1005 		goto error;
1006 	}
1007 
1008 	if (msize < c->msize)
1009 		c->msize = msize;
1010 
1011 error:
1012 	kfree(version);
1013 	p9_free_req(c, req);
1014 
1015 	return err;
1016 }
1017 
1018 struct p9_client *p9_client_create(const char *dev_name, char *options)
1019 {
1020 	int err;
1021 	struct p9_client *clnt;
1022 	char *client_id;
1023 
1024 	err = 0;
1025 	clnt = kmalloc(sizeof(struct p9_client), GFP_KERNEL);
1026 	if (!clnt)
1027 		return ERR_PTR(-ENOMEM);
1028 
1029 	clnt->trans_mod = NULL;
1030 	clnt->trans = NULL;
1031 
1032 	client_id = utsname()->nodename;
1033 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
1034 
1035 	spin_lock_init(&clnt->lock);
1036 	INIT_LIST_HEAD(&clnt->fidlist);
1037 
1038 	err = p9_tag_init(clnt);
1039 	if (err < 0)
1040 		goto free_client;
1041 
1042 	err = parse_opts(options, clnt);
1043 	if (err < 0)
1044 		goto destroy_tagpool;
1045 
1046 	if (!clnt->trans_mod)
1047 		clnt->trans_mod = v9fs_get_default_trans();
1048 
1049 	if (clnt->trans_mod == NULL) {
1050 		err = -EPROTONOSUPPORT;
1051 		p9_debug(P9_DEBUG_ERROR,
1052 			 "No transport defined or default transport\n");
1053 		goto destroy_tagpool;
1054 	}
1055 
1056 	clnt->fidpool = p9_idpool_create();
1057 	if (IS_ERR(clnt->fidpool)) {
1058 		err = PTR_ERR(clnt->fidpool);
1059 		goto put_trans;
1060 	}
1061 
1062 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
1063 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
1064 
1065 	err = clnt->trans_mod->create(clnt, dev_name, options);
1066 	if (err)
1067 		goto destroy_fidpool;
1068 
1069 	if (clnt->msize > clnt->trans_mod->maxsize)
1070 		clnt->msize = clnt->trans_mod->maxsize;
1071 
1072 	err = p9_client_version(clnt);
1073 	if (err)
1074 		goto close_trans;
1075 
1076 	return clnt;
1077 
1078 close_trans:
1079 	clnt->trans_mod->close(clnt);
1080 destroy_fidpool:
1081 	p9_idpool_destroy(clnt->fidpool);
1082 put_trans:
1083 	v9fs_put_trans(clnt->trans_mod);
1084 destroy_tagpool:
1085 	p9_idpool_destroy(clnt->tagpool);
1086 free_client:
1087 	kfree(clnt);
1088 	return ERR_PTR(err);
1089 }
1090 EXPORT_SYMBOL(p9_client_create);
1091 
1092 void p9_client_destroy(struct p9_client *clnt)
1093 {
1094 	struct p9_fid *fid, *fidptr;
1095 
1096 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1097 
1098 	if (clnt->trans_mod)
1099 		clnt->trans_mod->close(clnt);
1100 
1101 	v9fs_put_trans(clnt->trans_mod);
1102 
1103 	list_for_each_entry_safe(fid, fidptr, &clnt->fidlist, flist) {
1104 		pr_info("Found fid %d not clunked\n", fid->fid);
1105 		p9_fid_destroy(fid);
1106 	}
1107 
1108 	if (clnt->fidpool)
1109 		p9_idpool_destroy(clnt->fidpool);
1110 
1111 	p9_tag_cleanup(clnt);
1112 
1113 	kfree(clnt);
1114 }
1115 EXPORT_SYMBOL(p9_client_destroy);
1116 
1117 void p9_client_disconnect(struct p9_client *clnt)
1118 {
1119 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1120 	clnt->status = Disconnected;
1121 }
1122 EXPORT_SYMBOL(p9_client_disconnect);
1123 
1124 void p9_client_begin_disconnect(struct p9_client *clnt)
1125 {
1126 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1127 	clnt->status = BeginDisconnect;
1128 }
1129 EXPORT_SYMBOL(p9_client_begin_disconnect);
1130 
1131 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1132 	const char *uname, kuid_t n_uname, const char *aname)
1133 {
1134 	int err = 0;
1135 	struct p9_req_t *req;
1136 	struct p9_fid *fid;
1137 	struct p9_qid qid;
1138 
1139 
1140 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1141 		 afid ? afid->fid : -1, uname, aname);
1142 	fid = p9_fid_create(clnt);
1143 	if (IS_ERR(fid)) {
1144 		err = PTR_ERR(fid);
1145 		fid = NULL;
1146 		goto error;
1147 	}
1148 	fid->uid = n_uname;
1149 
1150 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
1151 			afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
1152 	if (IS_ERR(req)) {
1153 		err = PTR_ERR(req);
1154 		goto error;
1155 	}
1156 
1157 	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", &qid);
1158 	if (err) {
1159 		trace_9p_protocol_dump(clnt, req->rc);
1160 		p9_free_req(clnt, req);
1161 		goto error;
1162 	}
1163 
1164 	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
1165 		 qid.type, (unsigned long long)qid.path, qid.version);
1166 
1167 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1168 
1169 	p9_free_req(clnt, req);
1170 	return fid;
1171 
1172 error:
1173 	if (fid)
1174 		p9_fid_destroy(fid);
1175 	return ERR_PTR(err);
1176 }
1177 EXPORT_SYMBOL(p9_client_attach);
1178 
1179 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
1180 		const unsigned char * const *wnames, int clone)
1181 {
1182 	int err;
1183 	struct p9_client *clnt;
1184 	struct p9_fid *fid;
1185 	struct p9_qid *wqids;
1186 	struct p9_req_t *req;
1187 	uint16_t nwqids, count;
1188 
1189 	err = 0;
1190 	wqids = NULL;
1191 	clnt = oldfid->clnt;
1192 	if (clone) {
1193 		fid = p9_fid_create(clnt);
1194 		if (IS_ERR(fid)) {
1195 			err = PTR_ERR(fid);
1196 			fid = NULL;
1197 			goto error;
1198 		}
1199 
1200 		fid->uid = oldfid->uid;
1201 	} else
1202 		fid = oldfid;
1203 
1204 
1205 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1206 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1207 
1208 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1209 								nwname, wnames);
1210 	if (IS_ERR(req)) {
1211 		err = PTR_ERR(req);
1212 		goto error;
1213 	}
1214 
1215 	err = p9pdu_readf(req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1216 	if (err) {
1217 		trace_9p_protocol_dump(clnt, req->rc);
1218 		p9_free_req(clnt, req);
1219 		goto clunk_fid;
1220 	}
1221 	p9_free_req(clnt, req);
1222 
1223 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1224 
1225 	if (nwqids != nwname) {
1226 		err = -ENOENT;
1227 		goto clunk_fid;
1228 	}
1229 
1230 	for (count = 0; count < nwqids; count++)
1231 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1232 			count, wqids[count].type,
1233 			(unsigned long long)wqids[count].path,
1234 			wqids[count].version);
1235 
1236 	if (nwname)
1237 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1238 	else
1239 		fid->qid = oldfid->qid;
1240 
1241 	kfree(wqids);
1242 	return fid;
1243 
1244 clunk_fid:
1245 	kfree(wqids);
1246 	p9_client_clunk(fid);
1247 	fid = NULL;
1248 
1249 error:
1250 	if (fid && (fid != oldfid))
1251 		p9_fid_destroy(fid);
1252 
1253 	return ERR_PTR(err);
1254 }
1255 EXPORT_SYMBOL(p9_client_walk);
1256 
1257 int p9_client_open(struct p9_fid *fid, int mode)
1258 {
1259 	int err;
1260 	struct p9_client *clnt;
1261 	struct p9_req_t *req;
1262 	struct p9_qid qid;
1263 	int iounit;
1264 
1265 	clnt = fid->clnt;
1266 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1267 		p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1268 	err = 0;
1269 
1270 	if (fid->mode != -1)
1271 		return -EINVAL;
1272 
1273 	if (p9_is_proto_dotl(clnt))
1274 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode);
1275 	else
1276 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
1277 	if (IS_ERR(req)) {
1278 		err = PTR_ERR(req);
1279 		goto error;
1280 	}
1281 
1282 	err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1283 	if (err) {
1284 		trace_9p_protocol_dump(clnt, req->rc);
1285 		goto free_and_error;
1286 	}
1287 
1288 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1289 		p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1290 		(unsigned long long)qid.path, qid.version, iounit);
1291 
1292 	fid->mode = mode;
1293 	fid->iounit = iounit;
1294 
1295 free_and_error:
1296 	p9_free_req(clnt, req);
1297 error:
1298 	return err;
1299 }
1300 EXPORT_SYMBOL(p9_client_open);
1301 
1302 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags, u32 mode,
1303 		kgid_t gid, struct p9_qid *qid)
1304 {
1305 	int err = 0;
1306 	struct p9_client *clnt;
1307 	struct p9_req_t *req;
1308 	int iounit;
1309 
1310 	p9_debug(P9_DEBUG_9P,
1311 			">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1312 			ofid->fid, name, flags, mode,
1313 		 	from_kgid(&init_user_ns, gid));
1314 	clnt = ofid->clnt;
1315 
1316 	if (ofid->mode != -1)
1317 		return -EINVAL;
1318 
1319 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1320 			mode, gid);
1321 	if (IS_ERR(req)) {
1322 		err = PTR_ERR(req);
1323 		goto error;
1324 	}
1325 
1326 	err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", qid, &iounit);
1327 	if (err) {
1328 		trace_9p_protocol_dump(clnt, req->rc);
1329 		goto free_and_error;
1330 	}
1331 
1332 	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1333 			qid->type,
1334 			(unsigned long long)qid->path,
1335 			qid->version, iounit);
1336 
1337 	ofid->mode = mode;
1338 	ofid->iounit = iounit;
1339 
1340 free_and_error:
1341 	p9_free_req(clnt, req);
1342 error:
1343 	return err;
1344 }
1345 EXPORT_SYMBOL(p9_client_create_dotl);
1346 
1347 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1348 		     char *extension)
1349 {
1350 	int err;
1351 	struct p9_client *clnt;
1352 	struct p9_req_t *req;
1353 	struct p9_qid qid;
1354 	int iounit;
1355 
1356 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1357 						fid->fid, name, perm, mode);
1358 	err = 0;
1359 	clnt = fid->clnt;
1360 
1361 	if (fid->mode != -1)
1362 		return -EINVAL;
1363 
1364 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1365 				mode, extension);
1366 	if (IS_ERR(req)) {
1367 		err = PTR_ERR(req);
1368 		goto error;
1369 	}
1370 
1371 	err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1372 	if (err) {
1373 		trace_9p_protocol_dump(clnt, req->rc);
1374 		goto free_and_error;
1375 	}
1376 
1377 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1378 				qid.type,
1379 				(unsigned long long)qid.path,
1380 				qid.version, iounit);
1381 
1382 	fid->mode = mode;
1383 	fid->iounit = iounit;
1384 
1385 free_and_error:
1386 	p9_free_req(clnt, req);
1387 error:
1388 	return err;
1389 }
1390 EXPORT_SYMBOL(p9_client_fcreate);
1391 
1392 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1393 		const char *symtgt, kgid_t gid, struct p9_qid *qid)
1394 {
1395 	int err = 0;
1396 	struct p9_client *clnt;
1397 	struct p9_req_t *req;
1398 
1399 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1400 			dfid->fid, name, symtgt);
1401 	clnt = dfid->clnt;
1402 
1403 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1404 			gid);
1405 	if (IS_ERR(req)) {
1406 		err = PTR_ERR(req);
1407 		goto error;
1408 	}
1409 
1410 	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
1411 	if (err) {
1412 		trace_9p_protocol_dump(clnt, req->rc);
1413 		goto free_and_error;
1414 	}
1415 
1416 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1417 			qid->type, (unsigned long long)qid->path, qid->version);
1418 
1419 free_and_error:
1420 	p9_free_req(clnt, req);
1421 error:
1422 	return err;
1423 }
1424 EXPORT_SYMBOL(p9_client_symlink);
1425 
1426 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1427 {
1428 	struct p9_client *clnt;
1429 	struct p9_req_t *req;
1430 
1431 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1432 			dfid->fid, oldfid->fid, newname);
1433 	clnt = dfid->clnt;
1434 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1435 			newname);
1436 	if (IS_ERR(req))
1437 		return PTR_ERR(req);
1438 
1439 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1440 	p9_free_req(clnt, req);
1441 	return 0;
1442 }
1443 EXPORT_SYMBOL(p9_client_link);
1444 
1445 int p9_client_fsync(struct p9_fid *fid, int datasync)
1446 {
1447 	int err;
1448 	struct p9_client *clnt;
1449 	struct p9_req_t *req;
1450 
1451 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1452 			fid->fid, datasync);
1453 	err = 0;
1454 	clnt = fid->clnt;
1455 
1456 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1457 	if (IS_ERR(req)) {
1458 		err = PTR_ERR(req);
1459 		goto error;
1460 	}
1461 
1462 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1463 
1464 	p9_free_req(clnt, req);
1465 
1466 error:
1467 	return err;
1468 }
1469 EXPORT_SYMBOL(p9_client_fsync);
1470 
1471 int p9_client_clunk(struct p9_fid *fid)
1472 {
1473 	int err;
1474 	struct p9_client *clnt;
1475 	struct p9_req_t *req;
1476 	int retries = 0;
1477 
1478 	if (!fid) {
1479 		pr_warn("%s (%d): Trying to clunk with NULL fid\n",
1480 			__func__, task_pid_nr(current));
1481 		dump_stack();
1482 		return 0;
1483 	}
1484 
1485 again:
1486 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n", fid->fid,
1487 								retries);
1488 	err = 0;
1489 	clnt = fid->clnt;
1490 
1491 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1492 	if (IS_ERR(req)) {
1493 		err = PTR_ERR(req);
1494 		goto error;
1495 	}
1496 
1497 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1498 
1499 	p9_free_req(clnt, req);
1500 error:
1501 	/*
1502 	 * Fid is not valid even after a failed clunk
1503 	 * If interrupted, retry once then give up and
1504 	 * leak fid until umount.
1505 	 */
1506 	if (err == -ERESTARTSYS) {
1507 		if (retries++ == 0)
1508 			goto again;
1509 	} else
1510 		p9_fid_destroy(fid);
1511 	return err;
1512 }
1513 EXPORT_SYMBOL(p9_client_clunk);
1514 
1515 int p9_client_remove(struct p9_fid *fid)
1516 {
1517 	int err;
1518 	struct p9_client *clnt;
1519 	struct p9_req_t *req;
1520 
1521 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1522 	err = 0;
1523 	clnt = fid->clnt;
1524 
1525 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1526 	if (IS_ERR(req)) {
1527 		err = PTR_ERR(req);
1528 		goto error;
1529 	}
1530 
1531 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1532 
1533 	p9_free_req(clnt, req);
1534 error:
1535 	if (err == -ERESTARTSYS)
1536 		p9_client_clunk(fid);
1537 	else
1538 		p9_fid_destroy(fid);
1539 	return err;
1540 }
1541 EXPORT_SYMBOL(p9_client_remove);
1542 
1543 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1544 {
1545 	int err = 0;
1546 	struct p9_req_t *req;
1547 	struct p9_client *clnt;
1548 
1549 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1550 		   dfid->fid, name, flags);
1551 
1552 	clnt = dfid->clnt;
1553 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1554 	if (IS_ERR(req)) {
1555 		err = PTR_ERR(req);
1556 		goto error;
1557 	}
1558 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1559 
1560 	p9_free_req(clnt, req);
1561 error:
1562 	return err;
1563 }
1564 EXPORT_SYMBOL(p9_client_unlinkat);
1565 
1566 int
1567 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1568 {
1569 	struct p9_client *clnt = fid->clnt;
1570 	struct p9_req_t *req;
1571 	int total = 0;
1572 	*err = 0;
1573 
1574 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n",
1575 		   fid->fid, (unsigned long long) offset, (int)iov_iter_count(to));
1576 
1577 	while (iov_iter_count(to)) {
1578 		int count = iov_iter_count(to);
1579 		int rsize, non_zc = 0;
1580 		char *dataptr;
1581 
1582 		rsize = fid->iounit;
1583 		if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1584 			rsize = clnt->msize - P9_IOHDRSZ;
1585 
1586 		if (count < rsize)
1587 			rsize = count;
1588 
1589 		/* Don't bother zerocopy for small IO (< 1024) */
1590 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1591 			/*
1592 			 * response header len is 11
1593 			 * PDU Header(7) + IO Size (4)
1594 			 */
1595 			req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1596 					       0, 11, "dqd", fid->fid,
1597 					       offset, rsize);
1598 		} else {
1599 			non_zc = 1;
1600 			req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1601 					    rsize);
1602 		}
1603 		if (IS_ERR(req)) {
1604 			*err = PTR_ERR(req);
1605 			break;
1606 		}
1607 
1608 		*err = p9pdu_readf(req->rc, clnt->proto_version,
1609 				   "D", &count, &dataptr);
1610 		if (*err) {
1611 			trace_9p_protocol_dump(clnt, req->rc);
1612 			p9_free_req(clnt, req);
1613 			break;
1614 		}
1615 		if (rsize < count) {
1616 			pr_err("bogus RREAD count (%d > %d)\n", count, rsize);
1617 			count = rsize;
1618 		}
1619 
1620 		p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1621 		if (!count) {
1622 			p9_free_req(clnt, req);
1623 			break;
1624 		}
1625 
1626 		if (non_zc) {
1627 			int n = copy_to_iter(dataptr, count, to);
1628 			total += n;
1629 			offset += n;
1630 			if (n != count) {
1631 				*err = -EFAULT;
1632 				p9_free_req(clnt, req);
1633 				break;
1634 			}
1635 		} else {
1636 			iov_iter_advance(to, count);
1637 			total += count;
1638 			offset += count;
1639 		}
1640 		p9_free_req(clnt, req);
1641 	}
1642 	return total;
1643 }
1644 EXPORT_SYMBOL(p9_client_read);
1645 
1646 int
1647 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1648 {
1649 	struct p9_client *clnt = fid->clnt;
1650 	struct p9_req_t *req;
1651 	int total = 0;
1652 	*err = 0;
1653 
1654 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n",
1655 				fid->fid, (unsigned long long) offset,
1656 				iov_iter_count(from));
1657 
1658 	while (iov_iter_count(from)) {
1659 		int count = iov_iter_count(from);
1660 		int rsize = fid->iounit;
1661 		if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1662 			rsize = clnt->msize - P9_IOHDRSZ;
1663 
1664 		if (count < rsize)
1665 			rsize = count;
1666 
1667 		/* Don't bother zerocopy for small IO (< 1024) */
1668 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1669 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1670 					       rsize, P9_ZC_HDR_SZ, "dqd",
1671 					       fid->fid, offset, rsize);
1672 		} else {
1673 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1674 						    offset, rsize, from);
1675 		}
1676 		if (IS_ERR(req)) {
1677 			*err = PTR_ERR(req);
1678 			break;
1679 		}
1680 
1681 		*err = p9pdu_readf(req->rc, clnt->proto_version, "d", &count);
1682 		if (*err) {
1683 			trace_9p_protocol_dump(clnt, req->rc);
1684 			p9_free_req(clnt, req);
1685 			break;
1686 		}
1687 		if (rsize < count) {
1688 			pr_err("bogus RWRITE count (%d > %d)\n", count, rsize);
1689 			count = rsize;
1690 		}
1691 
1692 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1693 
1694 		p9_free_req(clnt, req);
1695 		iov_iter_advance(from, count);
1696 		total += count;
1697 		offset += count;
1698 	}
1699 	return total;
1700 }
1701 EXPORT_SYMBOL(p9_client_write);
1702 
1703 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1704 {
1705 	int err;
1706 	struct p9_client *clnt;
1707 	struct p9_wstat *ret = kmalloc(sizeof(struct p9_wstat), GFP_KERNEL);
1708 	struct p9_req_t *req;
1709 	u16 ignored;
1710 
1711 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1712 
1713 	if (!ret)
1714 		return ERR_PTR(-ENOMEM);
1715 
1716 	err = 0;
1717 	clnt = fid->clnt;
1718 
1719 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1720 	if (IS_ERR(req)) {
1721 		err = PTR_ERR(req);
1722 		goto error;
1723 	}
1724 
1725 	err = p9pdu_readf(req->rc, clnt->proto_version, "wS", &ignored, ret);
1726 	if (err) {
1727 		trace_9p_protocol_dump(clnt, req->rc);
1728 		p9_free_req(clnt, req);
1729 		goto error;
1730 	}
1731 
1732 	p9_debug(P9_DEBUG_9P,
1733 		"<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1734 		"<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1735 		"<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1736 		"<<<    uid=%d gid=%d n_muid=%d\n",
1737 		ret->size, ret->type, ret->dev, ret->qid.type,
1738 		(unsigned long long)ret->qid.path, ret->qid.version, ret->mode,
1739 		ret->atime, ret->mtime, (unsigned long long)ret->length,
1740 		ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1741 		from_kuid(&init_user_ns, ret->n_uid),
1742 		from_kgid(&init_user_ns, ret->n_gid),
1743 		from_kuid(&init_user_ns, ret->n_muid));
1744 
1745 	p9_free_req(clnt, req);
1746 	return ret;
1747 
1748 error:
1749 	kfree(ret);
1750 	return ERR_PTR(err);
1751 }
1752 EXPORT_SYMBOL(p9_client_stat);
1753 
1754 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1755 							u64 request_mask)
1756 {
1757 	int err;
1758 	struct p9_client *clnt;
1759 	struct p9_stat_dotl *ret = kmalloc(sizeof(struct p9_stat_dotl),
1760 								GFP_KERNEL);
1761 	struct p9_req_t *req;
1762 
1763 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1764 							fid->fid, request_mask);
1765 
1766 	if (!ret)
1767 		return ERR_PTR(-ENOMEM);
1768 
1769 	err = 0;
1770 	clnt = fid->clnt;
1771 
1772 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1773 	if (IS_ERR(req)) {
1774 		err = PTR_ERR(req);
1775 		goto error;
1776 	}
1777 
1778 	err = p9pdu_readf(req->rc, clnt->proto_version, "A", ret);
1779 	if (err) {
1780 		trace_9p_protocol_dump(clnt, req->rc);
1781 		p9_free_req(clnt, req);
1782 		goto error;
1783 	}
1784 
1785 	p9_debug(P9_DEBUG_9P,
1786 		"<<< RGETATTR st_result_mask=%lld\n"
1787 		"<<< qid=%x.%llx.%x\n"
1788 		"<<< st_mode=%8.8x st_nlink=%llu\n"
1789 		"<<< st_uid=%d st_gid=%d\n"
1790 		"<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1791 		"<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1792 		"<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1793 		"<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1794 		"<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1795 		"<<< st_gen=%lld st_data_version=%lld",
1796 		ret->st_result_mask, ret->qid.type, ret->qid.path,
1797 		ret->qid.version, ret->st_mode, ret->st_nlink,
1798 		from_kuid(&init_user_ns, ret->st_uid),
1799 		from_kgid(&init_user_ns, ret->st_gid),
1800 		ret->st_rdev, ret->st_size, ret->st_blksize,
1801 		ret->st_blocks, ret->st_atime_sec, ret->st_atime_nsec,
1802 		ret->st_mtime_sec, ret->st_mtime_nsec, ret->st_ctime_sec,
1803 		ret->st_ctime_nsec, ret->st_btime_sec, ret->st_btime_nsec,
1804 		ret->st_gen, ret->st_data_version);
1805 
1806 	p9_free_req(clnt, req);
1807 	return ret;
1808 
1809 error:
1810 	kfree(ret);
1811 	return ERR_PTR(err);
1812 }
1813 EXPORT_SYMBOL(p9_client_getattr_dotl);
1814 
1815 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1816 {
1817 	int ret;
1818 
1819 	/* NOTE: size shouldn't include its own length */
1820 	/* size[2] type[2] dev[4] qid[13] */
1821 	/* mode[4] atime[4] mtime[4] length[8]*/
1822 	/* name[s] uid[s] gid[s] muid[s] */
1823 	ret = 2+4+13+4+4+4+8+2+2+2+2;
1824 
1825 	if (wst->name)
1826 		ret += strlen(wst->name);
1827 	if (wst->uid)
1828 		ret += strlen(wst->uid);
1829 	if (wst->gid)
1830 		ret += strlen(wst->gid);
1831 	if (wst->muid)
1832 		ret += strlen(wst->muid);
1833 
1834 	if ((proto_version == p9_proto_2000u) ||
1835 		(proto_version == p9_proto_2000L)) {
1836 		ret += 2+4+4+4;	/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1837 		if (wst->extension)
1838 			ret += strlen(wst->extension);
1839 	}
1840 
1841 	return ret;
1842 }
1843 
1844 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1845 {
1846 	int err;
1847 	struct p9_req_t *req;
1848 	struct p9_client *clnt;
1849 
1850 	err = 0;
1851 	clnt = fid->clnt;
1852 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1853 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n", fid->fid);
1854 	p9_debug(P9_DEBUG_9P,
1855 		"     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1856 		"     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1857 		"     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1858 		"     uid=%d gid=%d n_muid=%d\n",
1859 		wst->size, wst->type, wst->dev, wst->qid.type,
1860 		(unsigned long long)wst->qid.path, wst->qid.version, wst->mode,
1861 		wst->atime, wst->mtime, (unsigned long long)wst->length,
1862 		wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1863 		from_kuid(&init_user_ns, wst->n_uid),
1864 		from_kgid(&init_user_ns, wst->n_gid),
1865 		from_kuid(&init_user_ns, wst->n_muid));
1866 
1867 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS", fid->fid, wst->size+2, wst);
1868 	if (IS_ERR(req)) {
1869 		err = PTR_ERR(req);
1870 		goto error;
1871 	}
1872 
1873 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1874 
1875 	p9_free_req(clnt, req);
1876 error:
1877 	return err;
1878 }
1879 EXPORT_SYMBOL(p9_client_wstat);
1880 
1881 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1882 {
1883 	int err;
1884 	struct p9_req_t *req;
1885 	struct p9_client *clnt;
1886 
1887 	err = 0;
1888 	clnt = fid->clnt;
1889 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1890 	p9_debug(P9_DEBUG_9P,
1891 		"    valid=%x mode=%x uid=%d gid=%d size=%lld\n"
1892 		"    atime_sec=%lld atime_nsec=%lld\n"
1893 		"    mtime_sec=%lld mtime_nsec=%lld\n",
1894 		p9attr->valid, p9attr->mode,
1895 		from_kuid(&init_user_ns, p9attr->uid),
1896 		from_kgid(&init_user_ns, p9attr->gid),
1897 		p9attr->size, p9attr->atime_sec, p9attr->atime_nsec,
1898 		p9attr->mtime_sec, p9attr->mtime_nsec);
1899 
1900 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1901 
1902 	if (IS_ERR(req)) {
1903 		err = PTR_ERR(req);
1904 		goto error;
1905 	}
1906 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1907 	p9_free_req(clnt, req);
1908 error:
1909 	return err;
1910 }
1911 EXPORT_SYMBOL(p9_client_setattr);
1912 
1913 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1914 {
1915 	int err;
1916 	struct p9_req_t *req;
1917 	struct p9_client *clnt;
1918 
1919 	err = 0;
1920 	clnt = fid->clnt;
1921 
1922 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1923 
1924 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1925 	if (IS_ERR(req)) {
1926 		err = PTR_ERR(req);
1927 		goto error;
1928 	}
1929 
1930 	err = p9pdu_readf(req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1931 		&sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1932 		&sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1933 	if (err) {
1934 		trace_9p_protocol_dump(clnt, req->rc);
1935 		p9_free_req(clnt, req);
1936 		goto error;
1937 	}
1938 
1939 	p9_debug(P9_DEBUG_9P, "<<< RSTATFS fid %d type 0x%lx bsize %ld "
1940 		"blocks %llu bfree %llu bavail %llu files %llu ffree %llu "
1941 		"fsid %llu namelen %ld\n",
1942 		fid->fid, (long unsigned int)sb->type, (long int)sb->bsize,
1943 		sb->blocks, sb->bfree, sb->bavail, sb->files,  sb->ffree,
1944 		sb->fsid, (long int)sb->namelen);
1945 
1946 	p9_free_req(clnt, req);
1947 error:
1948 	return err;
1949 }
1950 EXPORT_SYMBOL(p9_client_statfs);
1951 
1952 int p9_client_rename(struct p9_fid *fid,
1953 		     struct p9_fid *newdirfid, const char *name)
1954 {
1955 	int err;
1956 	struct p9_req_t *req;
1957 	struct p9_client *clnt;
1958 
1959 	err = 0;
1960 	clnt = fid->clnt;
1961 
1962 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1963 			fid->fid, newdirfid->fid, name);
1964 
1965 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1966 			newdirfid->fid, name);
1967 	if (IS_ERR(req)) {
1968 		err = PTR_ERR(req);
1969 		goto error;
1970 	}
1971 
1972 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1973 
1974 	p9_free_req(clnt, req);
1975 error:
1976 	return err;
1977 }
1978 EXPORT_SYMBOL(p9_client_rename);
1979 
1980 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
1981 		       struct p9_fid *newdirfid, const char *new_name)
1982 {
1983 	int err;
1984 	struct p9_req_t *req;
1985 	struct p9_client *clnt;
1986 
1987 	err = 0;
1988 	clnt = olddirfid->clnt;
1989 
1990 	p9_debug(P9_DEBUG_9P, ">>> TRENAMEAT olddirfid %d old name %s"
1991 		   " newdirfid %d new name %s\n", olddirfid->fid, old_name,
1992 		   newdirfid->fid, new_name);
1993 
1994 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
1995 			    old_name, newdirfid->fid, new_name);
1996 	if (IS_ERR(req)) {
1997 		err = PTR_ERR(req);
1998 		goto error;
1999 	}
2000 
2001 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
2002 		   newdirfid->fid, new_name);
2003 
2004 	p9_free_req(clnt, req);
2005 error:
2006 	return err;
2007 }
2008 EXPORT_SYMBOL(p9_client_renameat);
2009 
2010 /*
2011  * An xattrwalk without @attr_name gives the fid for the lisxattr namespace
2012  */
2013 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
2014 				const char *attr_name, u64 *attr_size)
2015 {
2016 	int err;
2017 	struct p9_req_t *req;
2018 	struct p9_client *clnt;
2019 	struct p9_fid *attr_fid;
2020 
2021 	err = 0;
2022 	clnt = file_fid->clnt;
2023 	attr_fid = p9_fid_create(clnt);
2024 	if (IS_ERR(attr_fid)) {
2025 		err = PTR_ERR(attr_fid);
2026 		attr_fid = NULL;
2027 		goto error;
2028 	}
2029 	p9_debug(P9_DEBUG_9P,
2030 		">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
2031 		file_fid->fid, attr_fid->fid, attr_name);
2032 
2033 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
2034 			file_fid->fid, attr_fid->fid, attr_name);
2035 	if (IS_ERR(req)) {
2036 		err = PTR_ERR(req);
2037 		goto error;
2038 	}
2039 	err = p9pdu_readf(req->rc, clnt->proto_version, "q", attr_size);
2040 	if (err) {
2041 		trace_9p_protocol_dump(clnt, req->rc);
2042 		p9_free_req(clnt, req);
2043 		goto clunk_fid;
2044 	}
2045 	p9_free_req(clnt, req);
2046 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
2047 		attr_fid->fid, *attr_size);
2048 	return attr_fid;
2049 clunk_fid:
2050 	p9_client_clunk(attr_fid);
2051 	attr_fid = NULL;
2052 error:
2053 	if (attr_fid && (attr_fid != file_fid))
2054 		p9_fid_destroy(attr_fid);
2055 
2056 	return ERR_PTR(err);
2057 }
2058 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
2059 
2060 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
2061 			u64 attr_size, int flags)
2062 {
2063 	int err;
2064 	struct p9_req_t *req;
2065 	struct p9_client *clnt;
2066 
2067 	p9_debug(P9_DEBUG_9P,
2068 		">>> TXATTRCREATE fid %d name  %s size %lld flag %d\n",
2069 		fid->fid, name, (long long)attr_size, flags);
2070 	err = 0;
2071 	clnt = fid->clnt;
2072 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
2073 			fid->fid, name, attr_size, flags);
2074 	if (IS_ERR(req)) {
2075 		err = PTR_ERR(req);
2076 		goto error;
2077 	}
2078 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
2079 	p9_free_req(clnt, req);
2080 error:
2081 	return err;
2082 }
2083 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
2084 
2085 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
2086 {
2087 	int err, rsize, non_zc = 0;
2088 	struct p9_client *clnt;
2089 	struct p9_req_t *req;
2090 	char *dataptr;
2091 	struct kvec kv = {.iov_base = data, .iov_len = count};
2092 	struct iov_iter to;
2093 
2094 	iov_iter_kvec(&to, READ | ITER_KVEC, &kv, 1, count);
2095 
2096 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
2097 				fid->fid, (unsigned long long) offset, count);
2098 
2099 	err = 0;
2100 	clnt = fid->clnt;
2101 
2102 	rsize = fid->iounit;
2103 	if (!rsize || rsize > clnt->msize-P9_READDIRHDRSZ)
2104 		rsize = clnt->msize - P9_READDIRHDRSZ;
2105 
2106 	if (count < rsize)
2107 		rsize = count;
2108 
2109 	/* Don't bother zerocopy for small IO (< 1024) */
2110 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2111 		/*
2112 		 * response header len is 11
2113 		 * PDU Header(7) + IO Size (4)
2114 		 */
2115 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2116 				       11, "dqd", fid->fid, offset, rsize);
2117 	} else {
2118 		non_zc = 1;
2119 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2120 				    offset, rsize);
2121 	}
2122 	if (IS_ERR(req)) {
2123 		err = PTR_ERR(req);
2124 		goto error;
2125 	}
2126 
2127 	err = p9pdu_readf(req->rc, clnt->proto_version, "D", &count, &dataptr);
2128 	if (err) {
2129 		trace_9p_protocol_dump(clnt, req->rc);
2130 		goto free_and_error;
2131 	}
2132 	if (rsize < count) {
2133 		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
2134 		count = rsize;
2135 	}
2136 
2137 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
2138 
2139 	if (non_zc)
2140 		memmove(data, dataptr, count);
2141 
2142 	p9_free_req(clnt, req);
2143 	return count;
2144 
2145 free_and_error:
2146 	p9_free_req(clnt, req);
2147 error:
2148 	return err;
2149 }
2150 EXPORT_SYMBOL(p9_client_readdir);
2151 
2152 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2153 			dev_t rdev, kgid_t gid, struct p9_qid *qid)
2154 {
2155 	int err;
2156 	struct p9_client *clnt;
2157 	struct p9_req_t *req;
2158 
2159 	err = 0;
2160 	clnt = fid->clnt;
2161 	p9_debug(P9_DEBUG_9P, ">>> TMKNOD fid %d name %s mode %d major %d "
2162 		"minor %d\n", fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2163 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2164 		MAJOR(rdev), MINOR(rdev), gid);
2165 	if (IS_ERR(req))
2166 		return PTR_ERR(req);
2167 
2168 	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
2169 	if (err) {
2170 		trace_9p_protocol_dump(clnt, req->rc);
2171 		goto error;
2172 	}
2173 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n", qid->type,
2174 				(unsigned long long)qid->path, qid->version);
2175 
2176 error:
2177 	p9_free_req(clnt, req);
2178 	return err;
2179 
2180 }
2181 EXPORT_SYMBOL(p9_client_mknod_dotl);
2182 
2183 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2184 				kgid_t gid, struct p9_qid *qid)
2185 {
2186 	int err;
2187 	struct p9_client *clnt;
2188 	struct p9_req_t *req;
2189 
2190 	err = 0;
2191 	clnt = fid->clnt;
2192 	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
2193 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
2194 	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg", fid->fid, name, mode,
2195 		gid);
2196 	if (IS_ERR(req))
2197 		return PTR_ERR(req);
2198 
2199 	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
2200 	if (err) {
2201 		trace_9p_protocol_dump(clnt, req->rc);
2202 		goto error;
2203 	}
2204 	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
2205 				(unsigned long long)qid->path, qid->version);
2206 
2207 error:
2208 	p9_free_req(clnt, req);
2209 	return err;
2210 
2211 }
2212 EXPORT_SYMBOL(p9_client_mkdir_dotl);
2213 
2214 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
2215 {
2216 	int err;
2217 	struct p9_client *clnt;
2218 	struct p9_req_t *req;
2219 
2220 	err = 0;
2221 	clnt = fid->clnt;
2222 	p9_debug(P9_DEBUG_9P, ">>> TLOCK fid %d type %i flags %d "
2223 			"start %lld length %lld proc_id %d client_id %s\n",
2224 			fid->fid, flock->type, flock->flags, flock->start,
2225 			flock->length, flock->proc_id, flock->client_id);
2226 
2227 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2228 				flock->flags, flock->start, flock->length,
2229 					flock->proc_id, flock->client_id);
2230 
2231 	if (IS_ERR(req))
2232 		return PTR_ERR(req);
2233 
2234 	err = p9pdu_readf(req->rc, clnt->proto_version, "b", status);
2235 	if (err) {
2236 		trace_9p_protocol_dump(clnt, req->rc);
2237 		goto error;
2238 	}
2239 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2240 error:
2241 	p9_free_req(clnt, req);
2242 	return err;
2243 
2244 }
2245 EXPORT_SYMBOL(p9_client_lock_dotl);
2246 
2247 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2248 {
2249 	int err;
2250 	struct p9_client *clnt;
2251 	struct p9_req_t *req;
2252 
2253 	err = 0;
2254 	clnt = fid->clnt;
2255 	p9_debug(P9_DEBUG_9P, ">>> TGETLOCK fid %d, type %i start %lld "
2256 		"length %lld proc_id %d client_id %s\n", fid->fid, glock->type,
2257 		glock->start, glock->length, glock->proc_id, glock->client_id);
2258 
2259 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,  glock->type,
2260 		glock->start, glock->length, glock->proc_id, glock->client_id);
2261 
2262 	if (IS_ERR(req))
2263 		return PTR_ERR(req);
2264 
2265 	err = p9pdu_readf(req->rc, clnt->proto_version, "bqqds", &glock->type,
2266 			&glock->start, &glock->length, &glock->proc_id,
2267 			&glock->client_id);
2268 	if (err) {
2269 		trace_9p_protocol_dump(clnt, req->rc);
2270 		goto error;
2271 	}
2272 	p9_debug(P9_DEBUG_9P, "<<< RGETLOCK type %i start %lld length %lld "
2273 		"proc_id %d client_id %s\n", glock->type, glock->start,
2274 		glock->length, glock->proc_id, glock->client_id);
2275 error:
2276 	p9_free_req(clnt, req);
2277 	return err;
2278 }
2279 EXPORT_SYMBOL(p9_client_getlock_dotl);
2280 
2281 int p9_client_readlink(struct p9_fid *fid, char **target)
2282 {
2283 	int err;
2284 	struct p9_client *clnt;
2285 	struct p9_req_t *req;
2286 
2287 	err = 0;
2288 	clnt = fid->clnt;
2289 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2290 
2291 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2292 	if (IS_ERR(req))
2293 		return PTR_ERR(req);
2294 
2295 	err = p9pdu_readf(req->rc, clnt->proto_version, "s", target);
2296 	if (err) {
2297 		trace_9p_protocol_dump(clnt, req->rc);
2298 		goto error;
2299 	}
2300 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2301 error:
2302 	p9_free_req(clnt, req);
2303 	return err;
2304 }
2305 EXPORT_SYMBOL(p9_client_readlink);
2306