xref: /openbmc/linux/net/9p/client.c (revision a17922de)
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 			}
202 			kfree(s);
203 			break;
204 		case Opt_legacy:
205 			clnt->proto_version = p9_proto_legacy;
206 			break;
207 		case Opt_version:
208 			s = match_strdup(&args[0]);
209 			if (!s) {
210 				ret = -ENOMEM;
211 				p9_debug(P9_DEBUG_ERROR,
212 					 "problem allocating copy of version arg\n");
213 				goto free_and_return;
214 			}
215 			r = get_protocol_version(s);
216 			if (r < 0)
217 				ret = r;
218 			else
219 				clnt->proto_version = r;
220 			kfree(s);
221 			break;
222 		default:
223 			continue;
224 		}
225 	}
226 
227 free_and_return:
228 	if (ret)
229 		v9fs_put_trans(clnt->trans_mod);
230 	kfree(tmp_options);
231 	return ret;
232 }
233 
234 static struct p9_fcall *p9_fcall_alloc(int alloc_msize)
235 {
236 	struct p9_fcall *fc;
237 	fc = kmalloc(sizeof(struct p9_fcall) + alloc_msize, GFP_NOFS);
238 	if (!fc)
239 		return NULL;
240 	fc->capacity = alloc_msize;
241 	fc->sdata = (char *) fc + sizeof(struct p9_fcall);
242 	return fc;
243 }
244 
245 /**
246  * p9_tag_alloc - lookup/allocate a request by tag
247  * @c: client session to lookup tag within
248  * @tag: numeric id for transaction
249  *
250  * this is a simple array lookup, but will grow the
251  * request_slots as necessary to accommodate transaction
252  * ids which did not previously have a slot.
253  *
254  * this code relies on the client spinlock to manage locks, its
255  * possible we should switch to something else, but I'd rather
256  * stick with something low-overhead for the common case.
257  *
258  */
259 
260 static struct p9_req_t *
261 p9_tag_alloc(struct p9_client *c, u16 tag, unsigned int max_size)
262 {
263 	unsigned long flags;
264 	int row, col;
265 	struct p9_req_t *req;
266 	int alloc_msize = min(c->msize, max_size);
267 
268 	/* This looks up the original request by tag so we know which
269 	 * buffer to read the data into */
270 	tag++;
271 
272 	if (tag >= c->max_tag) {
273 		spin_lock_irqsave(&c->lock, flags);
274 		/* check again since original check was outside of lock */
275 		while (tag >= c->max_tag) {
276 			row = (tag / P9_ROW_MAXTAG);
277 			c->reqs[row] = kcalloc(P9_ROW_MAXTAG,
278 					sizeof(struct p9_req_t), GFP_ATOMIC);
279 
280 			if (!c->reqs[row]) {
281 				pr_err("Couldn't grow tag array\n");
282 				spin_unlock_irqrestore(&c->lock, flags);
283 				return ERR_PTR(-ENOMEM);
284 			}
285 			for (col = 0; col < P9_ROW_MAXTAG; col++) {
286 				c->reqs[row][col].status = REQ_STATUS_IDLE;
287 				c->reqs[row][col].tc = NULL;
288 			}
289 			c->max_tag += P9_ROW_MAXTAG;
290 		}
291 		spin_unlock_irqrestore(&c->lock, flags);
292 	}
293 	row = tag / P9_ROW_MAXTAG;
294 	col = tag % P9_ROW_MAXTAG;
295 
296 	req = &c->reqs[row][col];
297 	if (!req->wq) {
298 		req->wq = kmalloc(sizeof(wait_queue_head_t), GFP_NOFS);
299 		if (!req->wq)
300 			goto grow_failed;
301 		init_waitqueue_head(req->wq);
302 	}
303 
304 	if (!req->tc)
305 		req->tc = p9_fcall_alloc(alloc_msize);
306 	if (!req->rc)
307 		req->rc = p9_fcall_alloc(alloc_msize);
308 	if (!req->tc || !req->rc)
309 		goto grow_failed;
310 
311 	p9pdu_reset(req->tc);
312 	p9pdu_reset(req->rc);
313 
314 	req->tc->tag = tag-1;
315 	req->status = REQ_STATUS_ALLOC;
316 
317 	return req;
318 
319 grow_failed:
320 	pr_err("Couldn't grow tag array\n");
321 	kfree(req->tc);
322 	kfree(req->rc);
323 	kfree(req->wq);
324 	req->tc = req->rc = NULL;
325 	req->wq = NULL;
326 	return ERR_PTR(-ENOMEM);
327 }
328 
329 /**
330  * p9_tag_lookup - lookup a request by tag
331  * @c: client session to lookup tag within
332  * @tag: numeric id for transaction
333  *
334  */
335 
336 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
337 {
338 	int row, col;
339 
340 	/* This looks up the original request by tag so we know which
341 	 * buffer to read the data into */
342 	tag++;
343 
344 	if(tag >= c->max_tag)
345 		return NULL;
346 
347 	row = tag / P9_ROW_MAXTAG;
348 	col = tag % P9_ROW_MAXTAG;
349 
350 	return &c->reqs[row][col];
351 }
352 EXPORT_SYMBOL(p9_tag_lookup);
353 
354 /**
355  * p9_tag_init - setup tags structure and contents
356  * @c:  v9fs client struct
357  *
358  * This initializes the tags structure for each client instance.
359  *
360  */
361 
362 static int p9_tag_init(struct p9_client *c)
363 {
364 	int err = 0;
365 
366 	c->tagpool = p9_idpool_create();
367 	if (IS_ERR(c->tagpool)) {
368 		err = PTR_ERR(c->tagpool);
369 		goto error;
370 	}
371 	err = p9_idpool_get(c->tagpool); /* reserve tag 0 */
372 	if (err < 0) {
373 		p9_idpool_destroy(c->tagpool);
374 		goto error;
375 	}
376 	c->max_tag = 0;
377 error:
378 	return err;
379 }
380 
381 /**
382  * p9_tag_cleanup - cleans up tags structure and reclaims resources
383  * @c:  v9fs client struct
384  *
385  * This frees resources associated with the tags structure
386  *
387  */
388 static void p9_tag_cleanup(struct p9_client *c)
389 {
390 	int row, col;
391 
392 	/* check to insure all requests are idle */
393 	for (row = 0; row < (c->max_tag/P9_ROW_MAXTAG); row++) {
394 		for (col = 0; col < P9_ROW_MAXTAG; col++) {
395 			if (c->reqs[row][col].status != REQ_STATUS_IDLE) {
396 				p9_debug(P9_DEBUG_MUX,
397 					 "Attempting to cleanup non-free tag %d,%d\n",
398 					 row, col);
399 				/* TODO: delay execution of cleanup */
400 				return;
401 			}
402 		}
403 	}
404 
405 	if (c->tagpool) {
406 		p9_idpool_put(0, c->tagpool); /* free reserved tag 0 */
407 		p9_idpool_destroy(c->tagpool);
408 	}
409 
410 	/* free requests associated with tags */
411 	for (row = 0; row < (c->max_tag/P9_ROW_MAXTAG); row++) {
412 		for (col = 0; col < P9_ROW_MAXTAG; col++) {
413 			kfree(c->reqs[row][col].wq);
414 			kfree(c->reqs[row][col].tc);
415 			kfree(c->reqs[row][col].rc);
416 		}
417 		kfree(c->reqs[row]);
418 	}
419 	c->max_tag = 0;
420 }
421 
422 /**
423  * p9_free_req - free a request and clean-up as necessary
424  * c: client state
425  * r: request to release
426  *
427  */
428 
429 static void p9_free_req(struct p9_client *c, struct p9_req_t *r)
430 {
431 	int tag = r->tc->tag;
432 	p9_debug(P9_DEBUG_MUX, "clnt %p req %p tag: %d\n", c, r, tag);
433 
434 	r->status = REQ_STATUS_IDLE;
435 	if (tag != P9_NOTAG && p9_idpool_check(tag, c->tagpool))
436 		p9_idpool_put(tag, c->tagpool);
437 }
438 
439 /**
440  * p9_client_cb - call back from transport to client
441  * c: client state
442  * req: request received
443  *
444  */
445 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
446 {
447 	p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc->tag);
448 
449 	/*
450 	 * This barrier is needed to make sure any change made to req before
451 	 * the other thread wakes up will indeed be seen by the waiting side.
452 	 */
453 	smp_wmb();
454 	req->status = status;
455 
456 	wake_up(req->wq);
457 	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc->tag);
458 }
459 EXPORT_SYMBOL(p9_client_cb);
460 
461 /**
462  * p9_parse_header - parse header arguments out of a packet
463  * @pdu: packet to parse
464  * @size: size of packet
465  * @type: type of request
466  * @tag: tag of packet
467  * @rewind: set if we need to rewind offset afterwards
468  */
469 
470 int
471 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type, int16_t *tag,
472 								int rewind)
473 {
474 	int8_t r_type;
475 	int16_t r_tag;
476 	int32_t r_size;
477 	int offset = pdu->offset;
478 	int err;
479 
480 	pdu->offset = 0;
481 	if (pdu->size == 0)
482 		pdu->size = 7;
483 
484 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
485 	if (err)
486 		goto rewind_and_exit;
487 
488 	pdu->size = r_size;
489 	pdu->id = r_type;
490 	pdu->tag = r_tag;
491 
492 	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
493 		 pdu->size, pdu->id, pdu->tag);
494 
495 	if (type)
496 		*type = r_type;
497 	if (tag)
498 		*tag = r_tag;
499 	if (size)
500 		*size = r_size;
501 
502 
503 rewind_and_exit:
504 	if (rewind)
505 		pdu->offset = offset;
506 	return err;
507 }
508 EXPORT_SYMBOL(p9_parse_header);
509 
510 /**
511  * p9_check_errors - check 9p packet for error return and process it
512  * @c: current client instance
513  * @req: request to parse and check for error conditions
514  *
515  * returns error code if one is discovered, otherwise returns 0
516  *
517  * this will have to be more complicated if we have multiple
518  * error packet types
519  */
520 
521 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
522 {
523 	int8_t type;
524 	int err;
525 	int ecode;
526 
527 	err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
528 	/*
529 	 * dump the response from server
530 	 * This should be after check errors which poplulate pdu_fcall.
531 	 */
532 	trace_9p_protocol_dump(c, req->rc);
533 	if (err) {
534 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
535 		return err;
536 	}
537 	if (type != P9_RERROR && type != P9_RLERROR)
538 		return 0;
539 
540 	if (!p9_is_proto_dotl(c)) {
541 		char *ename;
542 		err = p9pdu_readf(req->rc, c->proto_version, "s?d",
543 				  &ename, &ecode);
544 		if (err)
545 			goto out_err;
546 
547 		if (p9_is_proto_dotu(c) && ecode < 512)
548 			err = -ecode;
549 
550 		if (!err) {
551 			err = p9_errstr2errno(ename, strlen(ename));
552 
553 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
554 				 -ecode, ename);
555 		}
556 		kfree(ename);
557 	} else {
558 		err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode);
559 		err = -ecode;
560 
561 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
562 	}
563 
564 	return err;
565 
566 out_err:
567 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
568 
569 	return err;
570 }
571 
572 /**
573  * p9_check_zc_errors - check 9p packet for error return and process it
574  * @c: current client instance
575  * @req: request to parse and check for error conditions
576  * @in_hdrlen: Size of response protocol buffer.
577  *
578  * returns error code if one is discovered, otherwise returns 0
579  *
580  * this will have to be more complicated if we have multiple
581  * error packet types
582  */
583 
584 static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
585 			      struct iov_iter *uidata, int in_hdrlen)
586 {
587 	int err;
588 	int ecode;
589 	int8_t type;
590 	char *ename = NULL;
591 
592 	err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
593 	/*
594 	 * dump the response from server
595 	 * This should be after parse_header which poplulate pdu_fcall.
596 	 */
597 	trace_9p_protocol_dump(c, req->rc);
598 	if (err) {
599 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
600 		return err;
601 	}
602 
603 	if (type != P9_RERROR && type != P9_RLERROR)
604 		return 0;
605 
606 	if (!p9_is_proto_dotl(c)) {
607 		/* Error is reported in string format */
608 		int len;
609 		/* 7 = header size for RERROR; */
610 		int inline_len = in_hdrlen - 7;
611 
612 		len =  req->rc->size - req->rc->offset;
613 		if (len > (P9_ZC_HDR_SZ - 7)) {
614 			err = -EFAULT;
615 			goto out_err;
616 		}
617 
618 		ename = &req->rc->sdata[req->rc->offset];
619 		if (len > inline_len) {
620 			/* We have error in external buffer */
621 			if (!copy_from_iter_full(ename + inline_len,
622 					     len - inline_len, uidata)) {
623 				err = -EFAULT;
624 				goto out_err;
625 			}
626 		}
627 		ename = NULL;
628 		err = p9pdu_readf(req->rc, c->proto_version, "s?d",
629 				  &ename, &ecode);
630 		if (err)
631 			goto out_err;
632 
633 		if (p9_is_proto_dotu(c) && ecode < 512)
634 			err = -ecode;
635 
636 		if (!err) {
637 			err = p9_errstr2errno(ename, strlen(ename));
638 
639 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
640 				 -ecode, ename);
641 		}
642 		kfree(ename);
643 	} else {
644 		err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode);
645 		err = -ecode;
646 
647 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
648 	}
649 	return err;
650 
651 out_err:
652 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
653 	return err;
654 }
655 
656 static struct p9_req_t *
657 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
658 
659 /**
660  * p9_client_flush - flush (cancel) a request
661  * @c: client state
662  * @oldreq: request to cancel
663  *
664  * This sents a flush for a particular request and links
665  * the flush request to the original request.  The current
666  * code only supports a single flush request although the protocol
667  * allows for multiple flush requests to be sent for a single request.
668  *
669  */
670 
671 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
672 {
673 	struct p9_req_t *req;
674 	int16_t oldtag;
675 	int err;
676 
677 	err = p9_parse_header(oldreq->tc, NULL, NULL, &oldtag, 1);
678 	if (err)
679 		return err;
680 
681 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
682 
683 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
684 	if (IS_ERR(req))
685 		return PTR_ERR(req);
686 
687 	/*
688 	 * if we haven't received a response for oldreq,
689 	 * remove it from the list
690 	 */
691 	if (oldreq->status == REQ_STATUS_SENT)
692 		if (c->trans_mod->cancelled)
693 			c->trans_mod->cancelled(c, oldreq);
694 
695 	p9_free_req(c, req);
696 	return 0;
697 }
698 
699 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
700 					      int8_t type, int req_size,
701 					      const char *fmt, va_list ap)
702 {
703 	int tag, err;
704 	struct p9_req_t *req;
705 
706 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
707 
708 	/* we allow for any status other than disconnected */
709 	if (c->status == Disconnected)
710 		return ERR_PTR(-EIO);
711 
712 	/* if status is begin_disconnected we allow only clunk request */
713 	if ((c->status == BeginDisconnect) && (type != P9_TCLUNK))
714 		return ERR_PTR(-EIO);
715 
716 	tag = P9_NOTAG;
717 	if (type != P9_TVERSION) {
718 		tag = p9_idpool_get(c->tagpool);
719 		if (tag < 0)
720 			return ERR_PTR(-ENOMEM);
721 	}
722 
723 	req = p9_tag_alloc(c, tag, req_size);
724 	if (IS_ERR(req))
725 		return req;
726 
727 	/* marshall the data */
728 	p9pdu_prepare(req->tc, tag, type);
729 	err = p9pdu_vwritef(req->tc, c->proto_version, fmt, ap);
730 	if (err)
731 		goto reterr;
732 	p9pdu_finalize(c, req->tc);
733 	trace_9p_client_req(c, type, tag);
734 	return req;
735 reterr:
736 	p9_free_req(c, req);
737 	return ERR_PTR(err);
738 }
739 
740 /**
741  * p9_client_rpc - issue a request and wait for a response
742  * @c: client session
743  * @type: type of request
744  * @fmt: protocol format string (see protocol.c)
745  *
746  * Returns request structure (which client must free using p9_free_req)
747  */
748 
749 static struct p9_req_t *
750 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
751 {
752 	va_list ap;
753 	int sigpending, err;
754 	unsigned long flags;
755 	struct p9_req_t *req;
756 
757 	va_start(ap, fmt);
758 	req = p9_client_prepare_req(c, type, c->msize, fmt, ap);
759 	va_end(ap);
760 	if (IS_ERR(req))
761 		return req;
762 
763 	if (signal_pending(current)) {
764 		sigpending = 1;
765 		clear_thread_flag(TIF_SIGPENDING);
766 	} else
767 		sigpending = 0;
768 
769 	err = c->trans_mod->request(c, req);
770 	if (err < 0) {
771 		if (err != -ERESTARTSYS && err != -EFAULT)
772 			c->status = Disconnected;
773 		goto recalc_sigpending;
774 	}
775 again:
776 	/* Wait for the response */
777 	err = wait_event_killable(*req->wq, req->status >= REQ_STATUS_RCVD);
778 
779 	/*
780 	 * Make sure our req is coherent with regard to updates in other
781 	 * threads - echoes to wmb() in the callback
782 	 */
783 	smp_rmb();
784 
785 	if ((err == -ERESTARTSYS) && (c->status == Connected)
786 				  && (type == P9_TFLUSH)) {
787 		sigpending = 1;
788 		clear_thread_flag(TIF_SIGPENDING);
789 		goto again;
790 	}
791 
792 	if (req->status == REQ_STATUS_ERROR) {
793 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
794 		err = req->t_err;
795 	}
796 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
797 		p9_debug(P9_DEBUG_MUX, "flushing\n");
798 		sigpending = 1;
799 		clear_thread_flag(TIF_SIGPENDING);
800 
801 		if (c->trans_mod->cancel(c, req))
802 			p9_client_flush(c, req);
803 
804 		/* if we received the response anyway, don't signal error */
805 		if (req->status == REQ_STATUS_RCVD)
806 			err = 0;
807 	}
808 recalc_sigpending:
809 	if (sigpending) {
810 		spin_lock_irqsave(&current->sighand->siglock, flags);
811 		recalc_sigpending();
812 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
813 	}
814 	if (err < 0)
815 		goto reterr;
816 
817 	err = p9_check_errors(c, req);
818 	trace_9p_client_res(c, type, req->rc->tag, err);
819 	if (!err)
820 		return req;
821 reterr:
822 	p9_free_req(c, req);
823 	return ERR_PTR(safe_errno(err));
824 }
825 
826 /**
827  * p9_client_zc_rpc - issue a request and wait for a response
828  * @c: client session
829  * @type: type of request
830  * @uidata: destination for zero copy read
831  * @uodata: source for zero copy write
832  * @inlen: read buffer size
833  * @olen: write buffer size
834  * @hdrlen: reader header size, This is the size of response protocol data
835  * @fmt: protocol format string (see protocol.c)
836  *
837  * Returns request structure (which client must free using p9_free_req)
838  */
839 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
840 					 struct iov_iter *uidata,
841 					 struct iov_iter *uodata,
842 					 int inlen, int olen, int in_hdrlen,
843 					 const char *fmt, ...)
844 {
845 	va_list ap;
846 	int sigpending, err;
847 	unsigned long flags;
848 	struct p9_req_t *req;
849 
850 	va_start(ap, fmt);
851 	/*
852 	 * We allocate a inline protocol data of only 4k bytes.
853 	 * The actual content is passed in zero-copy fashion.
854 	 */
855 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, fmt, ap);
856 	va_end(ap);
857 	if (IS_ERR(req))
858 		return req;
859 
860 	if (signal_pending(current)) {
861 		sigpending = 1;
862 		clear_thread_flag(TIF_SIGPENDING);
863 	} else
864 		sigpending = 0;
865 
866 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
867 				       inlen, olen, in_hdrlen);
868 	if (err < 0) {
869 		if (err == -EIO)
870 			c->status = Disconnected;
871 		if (err != -ERESTARTSYS)
872 			goto recalc_sigpending;
873 	}
874 	if (req->status == REQ_STATUS_ERROR) {
875 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
876 		err = req->t_err;
877 	}
878 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
879 		p9_debug(P9_DEBUG_MUX, "flushing\n");
880 		sigpending = 1;
881 		clear_thread_flag(TIF_SIGPENDING);
882 
883 		if (c->trans_mod->cancel(c, req))
884 			p9_client_flush(c, req);
885 
886 		/* if we received the response anyway, don't signal error */
887 		if (req->status == REQ_STATUS_RCVD)
888 			err = 0;
889 	}
890 recalc_sigpending:
891 	if (sigpending) {
892 		spin_lock_irqsave(&current->sighand->siglock, flags);
893 		recalc_sigpending();
894 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
895 	}
896 	if (err < 0)
897 		goto reterr;
898 
899 	err = p9_check_zc_errors(c, req, uidata, in_hdrlen);
900 	trace_9p_client_res(c, type, req->rc->tag, err);
901 	if (!err)
902 		return req;
903 reterr:
904 	p9_free_req(c, req);
905 	return ERR_PTR(safe_errno(err));
906 }
907 
908 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
909 {
910 	int ret;
911 	struct p9_fid *fid;
912 	unsigned long flags;
913 
914 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
915 	fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
916 	if (!fid)
917 		return ERR_PTR(-ENOMEM);
918 
919 	ret = p9_idpool_get(clnt->fidpool);
920 	if (ret < 0) {
921 		ret = -ENOSPC;
922 		goto error;
923 	}
924 	fid->fid = ret;
925 
926 	memset(&fid->qid, 0, sizeof(struct p9_qid));
927 	fid->mode = -1;
928 	fid->uid = current_fsuid();
929 	fid->clnt = clnt;
930 	fid->rdir = NULL;
931 	spin_lock_irqsave(&clnt->lock, flags);
932 	list_add(&fid->flist, &clnt->fidlist);
933 	spin_unlock_irqrestore(&clnt->lock, flags);
934 
935 	return fid;
936 
937 error:
938 	kfree(fid);
939 	return ERR_PTR(ret);
940 }
941 
942 static void p9_fid_destroy(struct p9_fid *fid)
943 {
944 	struct p9_client *clnt;
945 	unsigned long flags;
946 
947 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
948 	clnt = fid->clnt;
949 	p9_idpool_put(fid->fid, clnt->fidpool);
950 	spin_lock_irqsave(&clnt->lock, flags);
951 	list_del(&fid->flist);
952 	spin_unlock_irqrestore(&clnt->lock, flags);
953 	kfree(fid->rdir);
954 	kfree(fid);
955 }
956 
957 static int p9_client_version(struct p9_client *c)
958 {
959 	int err = 0;
960 	struct p9_req_t *req;
961 	char *version;
962 	int msize;
963 
964 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
965 		 c->msize, c->proto_version);
966 
967 	switch (c->proto_version) {
968 	case p9_proto_2000L:
969 		req = p9_client_rpc(c, P9_TVERSION, "ds",
970 					c->msize, "9P2000.L");
971 		break;
972 	case p9_proto_2000u:
973 		req = p9_client_rpc(c, P9_TVERSION, "ds",
974 					c->msize, "9P2000.u");
975 		break;
976 	case p9_proto_legacy:
977 		req = p9_client_rpc(c, P9_TVERSION, "ds",
978 					c->msize, "9P2000");
979 		break;
980 	default:
981 		return -EINVAL;
982 	}
983 
984 	if (IS_ERR(req))
985 		return PTR_ERR(req);
986 
987 	err = p9pdu_readf(req->rc, c->proto_version, "ds", &msize, &version);
988 	if (err) {
989 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
990 		trace_9p_protocol_dump(c, req->rc);
991 		goto error;
992 	}
993 
994 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
995 	if (!strncmp(version, "9P2000.L", 8))
996 		c->proto_version = p9_proto_2000L;
997 	else if (!strncmp(version, "9P2000.u", 8))
998 		c->proto_version = p9_proto_2000u;
999 	else if (!strncmp(version, "9P2000", 6))
1000 		c->proto_version = p9_proto_legacy;
1001 	else {
1002 		err = -EREMOTEIO;
1003 		goto error;
1004 	}
1005 
1006 	if (msize < c->msize)
1007 		c->msize = msize;
1008 
1009 error:
1010 	kfree(version);
1011 	p9_free_req(c, req);
1012 
1013 	return err;
1014 }
1015 
1016 struct p9_client *p9_client_create(const char *dev_name, char *options)
1017 {
1018 	int err;
1019 	struct p9_client *clnt;
1020 	char *client_id;
1021 
1022 	err = 0;
1023 	clnt = kmalloc(sizeof(struct p9_client), GFP_KERNEL);
1024 	if (!clnt)
1025 		return ERR_PTR(-ENOMEM);
1026 
1027 	clnt->trans_mod = NULL;
1028 	clnt->trans = NULL;
1029 
1030 	client_id = utsname()->nodename;
1031 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
1032 
1033 	spin_lock_init(&clnt->lock);
1034 	INIT_LIST_HEAD(&clnt->fidlist);
1035 
1036 	err = p9_tag_init(clnt);
1037 	if (err < 0)
1038 		goto free_client;
1039 
1040 	err = parse_opts(options, clnt);
1041 	if (err < 0)
1042 		goto destroy_tagpool;
1043 
1044 	if (!clnt->trans_mod)
1045 		clnt->trans_mod = v9fs_get_default_trans();
1046 
1047 	if (clnt->trans_mod == NULL) {
1048 		err = -EPROTONOSUPPORT;
1049 		p9_debug(P9_DEBUG_ERROR,
1050 			 "No transport defined or default transport\n");
1051 		goto destroy_tagpool;
1052 	}
1053 
1054 	clnt->fidpool = p9_idpool_create();
1055 	if (IS_ERR(clnt->fidpool)) {
1056 		err = PTR_ERR(clnt->fidpool);
1057 		goto put_trans;
1058 	}
1059 
1060 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
1061 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
1062 
1063 	err = clnt->trans_mod->create(clnt, dev_name, options);
1064 	if (err)
1065 		goto destroy_fidpool;
1066 
1067 	if (clnt->msize > clnt->trans_mod->maxsize)
1068 		clnt->msize = clnt->trans_mod->maxsize;
1069 
1070 	err = p9_client_version(clnt);
1071 	if (err)
1072 		goto close_trans;
1073 
1074 	return clnt;
1075 
1076 close_trans:
1077 	clnt->trans_mod->close(clnt);
1078 destroy_fidpool:
1079 	p9_idpool_destroy(clnt->fidpool);
1080 put_trans:
1081 	v9fs_put_trans(clnt->trans_mod);
1082 destroy_tagpool:
1083 	p9_idpool_destroy(clnt->tagpool);
1084 free_client:
1085 	kfree(clnt);
1086 	return ERR_PTR(err);
1087 }
1088 EXPORT_SYMBOL(p9_client_create);
1089 
1090 void p9_client_destroy(struct p9_client *clnt)
1091 {
1092 	struct p9_fid *fid, *fidptr;
1093 
1094 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1095 
1096 	if (clnt->trans_mod)
1097 		clnt->trans_mod->close(clnt);
1098 
1099 	v9fs_put_trans(clnt->trans_mod);
1100 
1101 	list_for_each_entry_safe(fid, fidptr, &clnt->fidlist, flist) {
1102 		pr_info("Found fid %d not clunked\n", fid->fid);
1103 		p9_fid_destroy(fid);
1104 	}
1105 
1106 	if (clnt->fidpool)
1107 		p9_idpool_destroy(clnt->fidpool);
1108 
1109 	p9_tag_cleanup(clnt);
1110 
1111 	kfree(clnt);
1112 }
1113 EXPORT_SYMBOL(p9_client_destroy);
1114 
1115 void p9_client_disconnect(struct p9_client *clnt)
1116 {
1117 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1118 	clnt->status = Disconnected;
1119 }
1120 EXPORT_SYMBOL(p9_client_disconnect);
1121 
1122 void p9_client_begin_disconnect(struct p9_client *clnt)
1123 {
1124 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1125 	clnt->status = BeginDisconnect;
1126 }
1127 EXPORT_SYMBOL(p9_client_begin_disconnect);
1128 
1129 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1130 	const char *uname, kuid_t n_uname, const char *aname)
1131 {
1132 	int err = 0;
1133 	struct p9_req_t *req;
1134 	struct p9_fid *fid;
1135 	struct p9_qid qid;
1136 
1137 
1138 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1139 		 afid ? afid->fid : -1, uname, aname);
1140 	fid = p9_fid_create(clnt);
1141 	if (IS_ERR(fid)) {
1142 		err = PTR_ERR(fid);
1143 		fid = NULL;
1144 		goto error;
1145 	}
1146 	fid->uid = n_uname;
1147 
1148 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
1149 			afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
1150 	if (IS_ERR(req)) {
1151 		err = PTR_ERR(req);
1152 		goto error;
1153 	}
1154 
1155 	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", &qid);
1156 	if (err) {
1157 		trace_9p_protocol_dump(clnt, req->rc);
1158 		p9_free_req(clnt, req);
1159 		goto error;
1160 	}
1161 
1162 	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
1163 		 qid.type, (unsigned long long)qid.path, qid.version);
1164 
1165 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1166 
1167 	p9_free_req(clnt, req);
1168 	return fid;
1169 
1170 error:
1171 	if (fid)
1172 		p9_fid_destroy(fid);
1173 	return ERR_PTR(err);
1174 }
1175 EXPORT_SYMBOL(p9_client_attach);
1176 
1177 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
1178 		const unsigned char * const *wnames, int clone)
1179 {
1180 	int err;
1181 	struct p9_client *clnt;
1182 	struct p9_fid *fid;
1183 	struct p9_qid *wqids;
1184 	struct p9_req_t *req;
1185 	uint16_t nwqids, count;
1186 
1187 	err = 0;
1188 	wqids = NULL;
1189 	clnt = oldfid->clnt;
1190 	if (clone) {
1191 		fid = p9_fid_create(clnt);
1192 		if (IS_ERR(fid)) {
1193 			err = PTR_ERR(fid);
1194 			fid = NULL;
1195 			goto error;
1196 		}
1197 
1198 		fid->uid = oldfid->uid;
1199 	} else
1200 		fid = oldfid;
1201 
1202 
1203 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1204 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1205 
1206 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1207 								nwname, wnames);
1208 	if (IS_ERR(req)) {
1209 		err = PTR_ERR(req);
1210 		goto error;
1211 	}
1212 
1213 	err = p9pdu_readf(req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1214 	if (err) {
1215 		trace_9p_protocol_dump(clnt, req->rc);
1216 		p9_free_req(clnt, req);
1217 		goto clunk_fid;
1218 	}
1219 	p9_free_req(clnt, req);
1220 
1221 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1222 
1223 	if (nwqids != nwname) {
1224 		err = -ENOENT;
1225 		goto clunk_fid;
1226 	}
1227 
1228 	for (count = 0; count < nwqids; count++)
1229 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1230 			count, wqids[count].type,
1231 			(unsigned long long)wqids[count].path,
1232 			wqids[count].version);
1233 
1234 	if (nwname)
1235 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1236 	else
1237 		fid->qid = oldfid->qid;
1238 
1239 	kfree(wqids);
1240 	return fid;
1241 
1242 clunk_fid:
1243 	kfree(wqids);
1244 	p9_client_clunk(fid);
1245 	fid = NULL;
1246 
1247 error:
1248 	if (fid && (fid != oldfid))
1249 		p9_fid_destroy(fid);
1250 
1251 	return ERR_PTR(err);
1252 }
1253 EXPORT_SYMBOL(p9_client_walk);
1254 
1255 int p9_client_open(struct p9_fid *fid, int mode)
1256 {
1257 	int err;
1258 	struct p9_client *clnt;
1259 	struct p9_req_t *req;
1260 	struct p9_qid qid;
1261 	int iounit;
1262 
1263 	clnt = fid->clnt;
1264 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1265 		p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1266 	err = 0;
1267 
1268 	if (fid->mode != -1)
1269 		return -EINVAL;
1270 
1271 	if (p9_is_proto_dotl(clnt))
1272 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode);
1273 	else
1274 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
1275 	if (IS_ERR(req)) {
1276 		err = PTR_ERR(req);
1277 		goto error;
1278 	}
1279 
1280 	err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1281 	if (err) {
1282 		trace_9p_protocol_dump(clnt, req->rc);
1283 		goto free_and_error;
1284 	}
1285 
1286 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1287 		p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1288 		(unsigned long long)qid.path, qid.version, iounit);
1289 
1290 	fid->mode = mode;
1291 	fid->iounit = iounit;
1292 
1293 free_and_error:
1294 	p9_free_req(clnt, req);
1295 error:
1296 	return err;
1297 }
1298 EXPORT_SYMBOL(p9_client_open);
1299 
1300 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags, u32 mode,
1301 		kgid_t gid, struct p9_qid *qid)
1302 {
1303 	int err = 0;
1304 	struct p9_client *clnt;
1305 	struct p9_req_t *req;
1306 	int iounit;
1307 
1308 	p9_debug(P9_DEBUG_9P,
1309 			">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1310 			ofid->fid, name, flags, mode,
1311 		 	from_kgid(&init_user_ns, gid));
1312 	clnt = ofid->clnt;
1313 
1314 	if (ofid->mode != -1)
1315 		return -EINVAL;
1316 
1317 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1318 			mode, gid);
1319 	if (IS_ERR(req)) {
1320 		err = PTR_ERR(req);
1321 		goto error;
1322 	}
1323 
1324 	err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", qid, &iounit);
1325 	if (err) {
1326 		trace_9p_protocol_dump(clnt, req->rc);
1327 		goto free_and_error;
1328 	}
1329 
1330 	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1331 			qid->type,
1332 			(unsigned long long)qid->path,
1333 			qid->version, iounit);
1334 
1335 	ofid->mode = mode;
1336 	ofid->iounit = iounit;
1337 
1338 free_and_error:
1339 	p9_free_req(clnt, req);
1340 error:
1341 	return err;
1342 }
1343 EXPORT_SYMBOL(p9_client_create_dotl);
1344 
1345 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1346 		     char *extension)
1347 {
1348 	int err;
1349 	struct p9_client *clnt;
1350 	struct p9_req_t *req;
1351 	struct p9_qid qid;
1352 	int iounit;
1353 
1354 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1355 						fid->fid, name, perm, mode);
1356 	err = 0;
1357 	clnt = fid->clnt;
1358 
1359 	if (fid->mode != -1)
1360 		return -EINVAL;
1361 
1362 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1363 				mode, extension);
1364 	if (IS_ERR(req)) {
1365 		err = PTR_ERR(req);
1366 		goto error;
1367 	}
1368 
1369 	err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1370 	if (err) {
1371 		trace_9p_protocol_dump(clnt, req->rc);
1372 		goto free_and_error;
1373 	}
1374 
1375 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1376 				qid.type,
1377 				(unsigned long long)qid.path,
1378 				qid.version, iounit);
1379 
1380 	fid->mode = mode;
1381 	fid->iounit = iounit;
1382 
1383 free_and_error:
1384 	p9_free_req(clnt, req);
1385 error:
1386 	return err;
1387 }
1388 EXPORT_SYMBOL(p9_client_fcreate);
1389 
1390 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1391 		const char *symtgt, kgid_t gid, struct p9_qid *qid)
1392 {
1393 	int err = 0;
1394 	struct p9_client *clnt;
1395 	struct p9_req_t *req;
1396 
1397 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1398 			dfid->fid, name, symtgt);
1399 	clnt = dfid->clnt;
1400 
1401 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1402 			gid);
1403 	if (IS_ERR(req)) {
1404 		err = PTR_ERR(req);
1405 		goto error;
1406 	}
1407 
1408 	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
1409 	if (err) {
1410 		trace_9p_protocol_dump(clnt, req->rc);
1411 		goto free_and_error;
1412 	}
1413 
1414 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1415 			qid->type, (unsigned long long)qid->path, qid->version);
1416 
1417 free_and_error:
1418 	p9_free_req(clnt, req);
1419 error:
1420 	return err;
1421 }
1422 EXPORT_SYMBOL(p9_client_symlink);
1423 
1424 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1425 {
1426 	struct p9_client *clnt;
1427 	struct p9_req_t *req;
1428 
1429 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1430 			dfid->fid, oldfid->fid, newname);
1431 	clnt = dfid->clnt;
1432 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1433 			newname);
1434 	if (IS_ERR(req))
1435 		return PTR_ERR(req);
1436 
1437 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1438 	p9_free_req(clnt, req);
1439 	return 0;
1440 }
1441 EXPORT_SYMBOL(p9_client_link);
1442 
1443 int p9_client_fsync(struct p9_fid *fid, int datasync)
1444 {
1445 	int err;
1446 	struct p9_client *clnt;
1447 	struct p9_req_t *req;
1448 
1449 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1450 			fid->fid, datasync);
1451 	err = 0;
1452 	clnt = fid->clnt;
1453 
1454 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1455 	if (IS_ERR(req)) {
1456 		err = PTR_ERR(req);
1457 		goto error;
1458 	}
1459 
1460 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1461 
1462 	p9_free_req(clnt, req);
1463 
1464 error:
1465 	return err;
1466 }
1467 EXPORT_SYMBOL(p9_client_fsync);
1468 
1469 int p9_client_clunk(struct p9_fid *fid)
1470 {
1471 	int err;
1472 	struct p9_client *clnt;
1473 	struct p9_req_t *req;
1474 	int retries = 0;
1475 
1476 	if (!fid) {
1477 		pr_warn("%s (%d): Trying to clunk with NULL fid\n",
1478 			__func__, task_pid_nr(current));
1479 		dump_stack();
1480 		return 0;
1481 	}
1482 
1483 again:
1484 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n", fid->fid,
1485 								retries);
1486 	err = 0;
1487 	clnt = fid->clnt;
1488 
1489 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1490 	if (IS_ERR(req)) {
1491 		err = PTR_ERR(req);
1492 		goto error;
1493 	}
1494 
1495 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1496 
1497 	p9_free_req(clnt, req);
1498 error:
1499 	/*
1500 	 * Fid is not valid even after a failed clunk
1501 	 * If interrupted, retry once then give up and
1502 	 * leak fid until umount.
1503 	 */
1504 	if (err == -ERESTARTSYS) {
1505 		if (retries++ == 0)
1506 			goto again;
1507 	} else
1508 		p9_fid_destroy(fid);
1509 	return err;
1510 }
1511 EXPORT_SYMBOL(p9_client_clunk);
1512 
1513 int p9_client_remove(struct p9_fid *fid)
1514 {
1515 	int err;
1516 	struct p9_client *clnt;
1517 	struct p9_req_t *req;
1518 
1519 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1520 	err = 0;
1521 	clnt = fid->clnt;
1522 
1523 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1524 	if (IS_ERR(req)) {
1525 		err = PTR_ERR(req);
1526 		goto error;
1527 	}
1528 
1529 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1530 
1531 	p9_free_req(clnt, req);
1532 error:
1533 	if (err == -ERESTARTSYS)
1534 		p9_client_clunk(fid);
1535 	else
1536 		p9_fid_destroy(fid);
1537 	return err;
1538 }
1539 EXPORT_SYMBOL(p9_client_remove);
1540 
1541 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1542 {
1543 	int err = 0;
1544 	struct p9_req_t *req;
1545 	struct p9_client *clnt;
1546 
1547 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1548 		   dfid->fid, name, flags);
1549 
1550 	clnt = dfid->clnt;
1551 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1552 	if (IS_ERR(req)) {
1553 		err = PTR_ERR(req);
1554 		goto error;
1555 	}
1556 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1557 
1558 	p9_free_req(clnt, req);
1559 error:
1560 	return err;
1561 }
1562 EXPORT_SYMBOL(p9_client_unlinkat);
1563 
1564 int
1565 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1566 {
1567 	struct p9_client *clnt = fid->clnt;
1568 	struct p9_req_t *req;
1569 	int total = 0;
1570 	*err = 0;
1571 
1572 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n",
1573 		   fid->fid, (unsigned long long) offset, (int)iov_iter_count(to));
1574 
1575 	while (iov_iter_count(to)) {
1576 		int count = iov_iter_count(to);
1577 		int rsize, non_zc = 0;
1578 		char *dataptr;
1579 
1580 		rsize = fid->iounit;
1581 		if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1582 			rsize = clnt->msize - P9_IOHDRSZ;
1583 
1584 		if (count < rsize)
1585 			rsize = count;
1586 
1587 		/* Don't bother zerocopy for small IO (< 1024) */
1588 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1589 			/*
1590 			 * response header len is 11
1591 			 * PDU Header(7) + IO Size (4)
1592 			 */
1593 			req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1594 					       0, 11, "dqd", fid->fid,
1595 					       offset, rsize);
1596 		} else {
1597 			non_zc = 1;
1598 			req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1599 					    rsize);
1600 		}
1601 		if (IS_ERR(req)) {
1602 			*err = PTR_ERR(req);
1603 			break;
1604 		}
1605 
1606 		*err = p9pdu_readf(req->rc, clnt->proto_version,
1607 				   "D", &count, &dataptr);
1608 		if (*err) {
1609 			trace_9p_protocol_dump(clnt, req->rc);
1610 			p9_free_req(clnt, req);
1611 			break;
1612 		}
1613 		if (rsize < count) {
1614 			pr_err("bogus RREAD count (%d > %d)\n", count, rsize);
1615 			count = rsize;
1616 		}
1617 
1618 		p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1619 		if (!count) {
1620 			p9_free_req(clnt, req);
1621 			break;
1622 		}
1623 
1624 		if (non_zc) {
1625 			int n = copy_to_iter(dataptr, count, to);
1626 			total += n;
1627 			offset += n;
1628 			if (n != count) {
1629 				*err = -EFAULT;
1630 				p9_free_req(clnt, req);
1631 				break;
1632 			}
1633 		} else {
1634 			iov_iter_advance(to, count);
1635 			total += count;
1636 			offset += count;
1637 		}
1638 		p9_free_req(clnt, req);
1639 	}
1640 	return total;
1641 }
1642 EXPORT_SYMBOL(p9_client_read);
1643 
1644 int
1645 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1646 {
1647 	struct p9_client *clnt = fid->clnt;
1648 	struct p9_req_t *req;
1649 	int total = 0;
1650 	*err = 0;
1651 
1652 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n",
1653 				fid->fid, (unsigned long long) offset,
1654 				iov_iter_count(from));
1655 
1656 	while (iov_iter_count(from)) {
1657 		int count = iov_iter_count(from);
1658 		int rsize = fid->iounit;
1659 		if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1660 			rsize = clnt->msize - P9_IOHDRSZ;
1661 
1662 		if (count < rsize)
1663 			rsize = count;
1664 
1665 		/* Don't bother zerocopy for small IO (< 1024) */
1666 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1667 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1668 					       rsize, P9_ZC_HDR_SZ, "dqd",
1669 					       fid->fid, offset, rsize);
1670 		} else {
1671 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1672 						    offset, rsize, from);
1673 		}
1674 		if (IS_ERR(req)) {
1675 			*err = PTR_ERR(req);
1676 			break;
1677 		}
1678 
1679 		*err = p9pdu_readf(req->rc, clnt->proto_version, "d", &count);
1680 		if (*err) {
1681 			trace_9p_protocol_dump(clnt, req->rc);
1682 			p9_free_req(clnt, req);
1683 			break;
1684 		}
1685 		if (rsize < count) {
1686 			pr_err("bogus RWRITE count (%d > %d)\n", count, rsize);
1687 			count = rsize;
1688 		}
1689 
1690 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1691 
1692 		p9_free_req(clnt, req);
1693 		iov_iter_advance(from, count);
1694 		total += count;
1695 		offset += count;
1696 	}
1697 	return total;
1698 }
1699 EXPORT_SYMBOL(p9_client_write);
1700 
1701 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1702 {
1703 	int err;
1704 	struct p9_client *clnt;
1705 	struct p9_wstat *ret = kmalloc(sizeof(struct p9_wstat), GFP_KERNEL);
1706 	struct p9_req_t *req;
1707 	u16 ignored;
1708 
1709 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1710 
1711 	if (!ret)
1712 		return ERR_PTR(-ENOMEM);
1713 
1714 	err = 0;
1715 	clnt = fid->clnt;
1716 
1717 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1718 	if (IS_ERR(req)) {
1719 		err = PTR_ERR(req);
1720 		goto error;
1721 	}
1722 
1723 	err = p9pdu_readf(req->rc, clnt->proto_version, "wS", &ignored, ret);
1724 	if (err) {
1725 		trace_9p_protocol_dump(clnt, req->rc);
1726 		p9_free_req(clnt, req);
1727 		goto error;
1728 	}
1729 
1730 	p9_debug(P9_DEBUG_9P,
1731 		"<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1732 		"<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1733 		"<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1734 		"<<<    uid=%d gid=%d n_muid=%d\n",
1735 		ret->size, ret->type, ret->dev, ret->qid.type,
1736 		(unsigned long long)ret->qid.path, ret->qid.version, ret->mode,
1737 		ret->atime, ret->mtime, (unsigned long long)ret->length,
1738 		ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1739 		from_kuid(&init_user_ns, ret->n_uid),
1740 		from_kgid(&init_user_ns, ret->n_gid),
1741 		from_kuid(&init_user_ns, ret->n_muid));
1742 
1743 	p9_free_req(clnt, req);
1744 	return ret;
1745 
1746 error:
1747 	kfree(ret);
1748 	return ERR_PTR(err);
1749 }
1750 EXPORT_SYMBOL(p9_client_stat);
1751 
1752 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1753 							u64 request_mask)
1754 {
1755 	int err;
1756 	struct p9_client *clnt;
1757 	struct p9_stat_dotl *ret = kmalloc(sizeof(struct p9_stat_dotl),
1758 								GFP_KERNEL);
1759 	struct p9_req_t *req;
1760 
1761 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1762 							fid->fid, request_mask);
1763 
1764 	if (!ret)
1765 		return ERR_PTR(-ENOMEM);
1766 
1767 	err = 0;
1768 	clnt = fid->clnt;
1769 
1770 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1771 	if (IS_ERR(req)) {
1772 		err = PTR_ERR(req);
1773 		goto error;
1774 	}
1775 
1776 	err = p9pdu_readf(req->rc, clnt->proto_version, "A", ret);
1777 	if (err) {
1778 		trace_9p_protocol_dump(clnt, req->rc);
1779 		p9_free_req(clnt, req);
1780 		goto error;
1781 	}
1782 
1783 	p9_debug(P9_DEBUG_9P,
1784 		"<<< RGETATTR st_result_mask=%lld\n"
1785 		"<<< qid=%x.%llx.%x\n"
1786 		"<<< st_mode=%8.8x st_nlink=%llu\n"
1787 		"<<< st_uid=%d st_gid=%d\n"
1788 		"<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1789 		"<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1790 		"<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1791 		"<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1792 		"<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1793 		"<<< st_gen=%lld st_data_version=%lld",
1794 		ret->st_result_mask, ret->qid.type, ret->qid.path,
1795 		ret->qid.version, ret->st_mode, ret->st_nlink,
1796 		from_kuid(&init_user_ns, ret->st_uid),
1797 		from_kgid(&init_user_ns, ret->st_gid),
1798 		ret->st_rdev, ret->st_size, ret->st_blksize,
1799 		ret->st_blocks, ret->st_atime_sec, ret->st_atime_nsec,
1800 		ret->st_mtime_sec, ret->st_mtime_nsec, ret->st_ctime_sec,
1801 		ret->st_ctime_nsec, ret->st_btime_sec, ret->st_btime_nsec,
1802 		ret->st_gen, ret->st_data_version);
1803 
1804 	p9_free_req(clnt, req);
1805 	return ret;
1806 
1807 error:
1808 	kfree(ret);
1809 	return ERR_PTR(err);
1810 }
1811 EXPORT_SYMBOL(p9_client_getattr_dotl);
1812 
1813 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1814 {
1815 	int ret;
1816 
1817 	/* NOTE: size shouldn't include its own length */
1818 	/* size[2] type[2] dev[4] qid[13] */
1819 	/* mode[4] atime[4] mtime[4] length[8]*/
1820 	/* name[s] uid[s] gid[s] muid[s] */
1821 	ret = 2+4+13+4+4+4+8+2+2+2+2;
1822 
1823 	if (wst->name)
1824 		ret += strlen(wst->name);
1825 	if (wst->uid)
1826 		ret += strlen(wst->uid);
1827 	if (wst->gid)
1828 		ret += strlen(wst->gid);
1829 	if (wst->muid)
1830 		ret += strlen(wst->muid);
1831 
1832 	if ((proto_version == p9_proto_2000u) ||
1833 		(proto_version == p9_proto_2000L)) {
1834 		ret += 2+4+4+4;	/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1835 		if (wst->extension)
1836 			ret += strlen(wst->extension);
1837 	}
1838 
1839 	return ret;
1840 }
1841 
1842 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1843 {
1844 	int err;
1845 	struct p9_req_t *req;
1846 	struct p9_client *clnt;
1847 
1848 	err = 0;
1849 	clnt = fid->clnt;
1850 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1851 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n", fid->fid);
1852 	p9_debug(P9_DEBUG_9P,
1853 		"     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1854 		"     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1855 		"     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1856 		"     uid=%d gid=%d n_muid=%d\n",
1857 		wst->size, wst->type, wst->dev, wst->qid.type,
1858 		(unsigned long long)wst->qid.path, wst->qid.version, wst->mode,
1859 		wst->atime, wst->mtime, (unsigned long long)wst->length,
1860 		wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1861 		from_kuid(&init_user_ns, wst->n_uid),
1862 		from_kgid(&init_user_ns, wst->n_gid),
1863 		from_kuid(&init_user_ns, wst->n_muid));
1864 
1865 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS", fid->fid, wst->size+2, wst);
1866 	if (IS_ERR(req)) {
1867 		err = PTR_ERR(req);
1868 		goto error;
1869 	}
1870 
1871 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1872 
1873 	p9_free_req(clnt, req);
1874 error:
1875 	return err;
1876 }
1877 EXPORT_SYMBOL(p9_client_wstat);
1878 
1879 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1880 {
1881 	int err;
1882 	struct p9_req_t *req;
1883 	struct p9_client *clnt;
1884 
1885 	err = 0;
1886 	clnt = fid->clnt;
1887 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1888 	p9_debug(P9_DEBUG_9P,
1889 		"    valid=%x mode=%x uid=%d gid=%d size=%lld\n"
1890 		"    atime_sec=%lld atime_nsec=%lld\n"
1891 		"    mtime_sec=%lld mtime_nsec=%lld\n",
1892 		p9attr->valid, p9attr->mode,
1893 		from_kuid(&init_user_ns, p9attr->uid),
1894 		from_kgid(&init_user_ns, p9attr->gid),
1895 		p9attr->size, p9attr->atime_sec, p9attr->atime_nsec,
1896 		p9attr->mtime_sec, p9attr->mtime_nsec);
1897 
1898 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1899 
1900 	if (IS_ERR(req)) {
1901 		err = PTR_ERR(req);
1902 		goto error;
1903 	}
1904 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1905 	p9_free_req(clnt, req);
1906 error:
1907 	return err;
1908 }
1909 EXPORT_SYMBOL(p9_client_setattr);
1910 
1911 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1912 {
1913 	int err;
1914 	struct p9_req_t *req;
1915 	struct p9_client *clnt;
1916 
1917 	err = 0;
1918 	clnt = fid->clnt;
1919 
1920 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1921 
1922 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1923 	if (IS_ERR(req)) {
1924 		err = PTR_ERR(req);
1925 		goto error;
1926 	}
1927 
1928 	err = p9pdu_readf(req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1929 		&sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1930 		&sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1931 	if (err) {
1932 		trace_9p_protocol_dump(clnt, req->rc);
1933 		p9_free_req(clnt, req);
1934 		goto error;
1935 	}
1936 
1937 	p9_debug(P9_DEBUG_9P, "<<< RSTATFS fid %d type 0x%lx bsize %ld "
1938 		"blocks %llu bfree %llu bavail %llu files %llu ffree %llu "
1939 		"fsid %llu namelen %ld\n",
1940 		fid->fid, (long unsigned int)sb->type, (long int)sb->bsize,
1941 		sb->blocks, sb->bfree, sb->bavail, sb->files,  sb->ffree,
1942 		sb->fsid, (long int)sb->namelen);
1943 
1944 	p9_free_req(clnt, req);
1945 error:
1946 	return err;
1947 }
1948 EXPORT_SYMBOL(p9_client_statfs);
1949 
1950 int p9_client_rename(struct p9_fid *fid,
1951 		     struct p9_fid *newdirfid, const char *name)
1952 {
1953 	int err;
1954 	struct p9_req_t *req;
1955 	struct p9_client *clnt;
1956 
1957 	err = 0;
1958 	clnt = fid->clnt;
1959 
1960 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1961 			fid->fid, newdirfid->fid, name);
1962 
1963 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1964 			newdirfid->fid, name);
1965 	if (IS_ERR(req)) {
1966 		err = PTR_ERR(req);
1967 		goto error;
1968 	}
1969 
1970 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1971 
1972 	p9_free_req(clnt, req);
1973 error:
1974 	return err;
1975 }
1976 EXPORT_SYMBOL(p9_client_rename);
1977 
1978 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
1979 		       struct p9_fid *newdirfid, const char *new_name)
1980 {
1981 	int err;
1982 	struct p9_req_t *req;
1983 	struct p9_client *clnt;
1984 
1985 	err = 0;
1986 	clnt = olddirfid->clnt;
1987 
1988 	p9_debug(P9_DEBUG_9P, ">>> TRENAMEAT olddirfid %d old name %s"
1989 		   " newdirfid %d new name %s\n", olddirfid->fid, old_name,
1990 		   newdirfid->fid, new_name);
1991 
1992 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
1993 			    old_name, newdirfid->fid, new_name);
1994 	if (IS_ERR(req)) {
1995 		err = PTR_ERR(req);
1996 		goto error;
1997 	}
1998 
1999 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
2000 		   newdirfid->fid, new_name);
2001 
2002 	p9_free_req(clnt, req);
2003 error:
2004 	return err;
2005 }
2006 EXPORT_SYMBOL(p9_client_renameat);
2007 
2008 /*
2009  * An xattrwalk without @attr_name gives the fid for the lisxattr namespace
2010  */
2011 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
2012 				const char *attr_name, u64 *attr_size)
2013 {
2014 	int err;
2015 	struct p9_req_t *req;
2016 	struct p9_client *clnt;
2017 	struct p9_fid *attr_fid;
2018 
2019 	err = 0;
2020 	clnt = file_fid->clnt;
2021 	attr_fid = p9_fid_create(clnt);
2022 	if (IS_ERR(attr_fid)) {
2023 		err = PTR_ERR(attr_fid);
2024 		attr_fid = NULL;
2025 		goto error;
2026 	}
2027 	p9_debug(P9_DEBUG_9P,
2028 		">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
2029 		file_fid->fid, attr_fid->fid, attr_name);
2030 
2031 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
2032 			file_fid->fid, attr_fid->fid, attr_name);
2033 	if (IS_ERR(req)) {
2034 		err = PTR_ERR(req);
2035 		goto error;
2036 	}
2037 	err = p9pdu_readf(req->rc, clnt->proto_version, "q", attr_size);
2038 	if (err) {
2039 		trace_9p_protocol_dump(clnt, req->rc);
2040 		p9_free_req(clnt, req);
2041 		goto clunk_fid;
2042 	}
2043 	p9_free_req(clnt, req);
2044 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
2045 		attr_fid->fid, *attr_size);
2046 	return attr_fid;
2047 clunk_fid:
2048 	p9_client_clunk(attr_fid);
2049 	attr_fid = NULL;
2050 error:
2051 	if (attr_fid && (attr_fid != file_fid))
2052 		p9_fid_destroy(attr_fid);
2053 
2054 	return ERR_PTR(err);
2055 }
2056 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
2057 
2058 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
2059 			u64 attr_size, int flags)
2060 {
2061 	int err;
2062 	struct p9_req_t *req;
2063 	struct p9_client *clnt;
2064 
2065 	p9_debug(P9_DEBUG_9P,
2066 		">>> TXATTRCREATE fid %d name  %s size %lld flag %d\n",
2067 		fid->fid, name, (long long)attr_size, flags);
2068 	err = 0;
2069 	clnt = fid->clnt;
2070 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
2071 			fid->fid, name, attr_size, flags);
2072 	if (IS_ERR(req)) {
2073 		err = PTR_ERR(req);
2074 		goto error;
2075 	}
2076 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
2077 	p9_free_req(clnt, req);
2078 error:
2079 	return err;
2080 }
2081 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
2082 
2083 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
2084 {
2085 	int err, rsize, non_zc = 0;
2086 	struct p9_client *clnt;
2087 	struct p9_req_t *req;
2088 	char *dataptr;
2089 	struct kvec kv = {.iov_base = data, .iov_len = count};
2090 	struct iov_iter to;
2091 
2092 	iov_iter_kvec(&to, READ | ITER_KVEC, &kv, 1, count);
2093 
2094 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
2095 				fid->fid, (unsigned long long) offset, count);
2096 
2097 	err = 0;
2098 	clnt = fid->clnt;
2099 
2100 	rsize = fid->iounit;
2101 	if (!rsize || rsize > clnt->msize-P9_READDIRHDRSZ)
2102 		rsize = clnt->msize - P9_READDIRHDRSZ;
2103 
2104 	if (count < rsize)
2105 		rsize = count;
2106 
2107 	/* Don't bother zerocopy for small IO (< 1024) */
2108 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2109 		/*
2110 		 * response header len is 11
2111 		 * PDU Header(7) + IO Size (4)
2112 		 */
2113 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2114 				       11, "dqd", fid->fid, offset, rsize);
2115 	} else {
2116 		non_zc = 1;
2117 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2118 				    offset, rsize);
2119 	}
2120 	if (IS_ERR(req)) {
2121 		err = PTR_ERR(req);
2122 		goto error;
2123 	}
2124 
2125 	err = p9pdu_readf(req->rc, clnt->proto_version, "D", &count, &dataptr);
2126 	if (err) {
2127 		trace_9p_protocol_dump(clnt, req->rc);
2128 		goto free_and_error;
2129 	}
2130 	if (rsize < count) {
2131 		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
2132 		count = rsize;
2133 	}
2134 
2135 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
2136 
2137 	if (non_zc)
2138 		memmove(data, dataptr, count);
2139 
2140 	p9_free_req(clnt, req);
2141 	return count;
2142 
2143 free_and_error:
2144 	p9_free_req(clnt, req);
2145 error:
2146 	return err;
2147 }
2148 EXPORT_SYMBOL(p9_client_readdir);
2149 
2150 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2151 			dev_t rdev, kgid_t gid, struct p9_qid *qid)
2152 {
2153 	int err;
2154 	struct p9_client *clnt;
2155 	struct p9_req_t *req;
2156 
2157 	err = 0;
2158 	clnt = fid->clnt;
2159 	p9_debug(P9_DEBUG_9P, ">>> TMKNOD fid %d name %s mode %d major %d "
2160 		"minor %d\n", fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2161 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2162 		MAJOR(rdev), MINOR(rdev), gid);
2163 	if (IS_ERR(req))
2164 		return PTR_ERR(req);
2165 
2166 	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
2167 	if (err) {
2168 		trace_9p_protocol_dump(clnt, req->rc);
2169 		goto error;
2170 	}
2171 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n", qid->type,
2172 				(unsigned long long)qid->path, qid->version);
2173 
2174 error:
2175 	p9_free_req(clnt, req);
2176 	return err;
2177 
2178 }
2179 EXPORT_SYMBOL(p9_client_mknod_dotl);
2180 
2181 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2182 				kgid_t gid, struct p9_qid *qid)
2183 {
2184 	int err;
2185 	struct p9_client *clnt;
2186 	struct p9_req_t *req;
2187 
2188 	err = 0;
2189 	clnt = fid->clnt;
2190 	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
2191 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
2192 	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg", fid->fid, name, mode,
2193 		gid);
2194 	if (IS_ERR(req))
2195 		return PTR_ERR(req);
2196 
2197 	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
2198 	if (err) {
2199 		trace_9p_protocol_dump(clnt, req->rc);
2200 		goto error;
2201 	}
2202 	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
2203 				(unsigned long long)qid->path, qid->version);
2204 
2205 error:
2206 	p9_free_req(clnt, req);
2207 	return err;
2208 
2209 }
2210 EXPORT_SYMBOL(p9_client_mkdir_dotl);
2211 
2212 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
2213 {
2214 	int err;
2215 	struct p9_client *clnt;
2216 	struct p9_req_t *req;
2217 
2218 	err = 0;
2219 	clnt = fid->clnt;
2220 	p9_debug(P9_DEBUG_9P, ">>> TLOCK fid %d type %i flags %d "
2221 			"start %lld length %lld proc_id %d client_id %s\n",
2222 			fid->fid, flock->type, flock->flags, flock->start,
2223 			flock->length, flock->proc_id, flock->client_id);
2224 
2225 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2226 				flock->flags, flock->start, flock->length,
2227 					flock->proc_id, flock->client_id);
2228 
2229 	if (IS_ERR(req))
2230 		return PTR_ERR(req);
2231 
2232 	err = p9pdu_readf(req->rc, clnt->proto_version, "b", status);
2233 	if (err) {
2234 		trace_9p_protocol_dump(clnt, req->rc);
2235 		goto error;
2236 	}
2237 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2238 error:
2239 	p9_free_req(clnt, req);
2240 	return err;
2241 
2242 }
2243 EXPORT_SYMBOL(p9_client_lock_dotl);
2244 
2245 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2246 {
2247 	int err;
2248 	struct p9_client *clnt;
2249 	struct p9_req_t *req;
2250 
2251 	err = 0;
2252 	clnt = fid->clnt;
2253 	p9_debug(P9_DEBUG_9P, ">>> TGETLOCK fid %d, type %i start %lld "
2254 		"length %lld proc_id %d client_id %s\n", fid->fid, glock->type,
2255 		glock->start, glock->length, glock->proc_id, glock->client_id);
2256 
2257 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,  glock->type,
2258 		glock->start, glock->length, glock->proc_id, glock->client_id);
2259 
2260 	if (IS_ERR(req))
2261 		return PTR_ERR(req);
2262 
2263 	err = p9pdu_readf(req->rc, clnt->proto_version, "bqqds", &glock->type,
2264 			&glock->start, &glock->length, &glock->proc_id,
2265 			&glock->client_id);
2266 	if (err) {
2267 		trace_9p_protocol_dump(clnt, req->rc);
2268 		goto error;
2269 	}
2270 	p9_debug(P9_DEBUG_9P, "<<< RGETLOCK type %i start %lld length %lld "
2271 		"proc_id %d client_id %s\n", glock->type, glock->start,
2272 		glock->length, glock->proc_id, glock->client_id);
2273 error:
2274 	p9_free_req(clnt, req);
2275 	return err;
2276 }
2277 EXPORT_SYMBOL(p9_client_getlock_dotl);
2278 
2279 int p9_client_readlink(struct p9_fid *fid, char **target)
2280 {
2281 	int err;
2282 	struct p9_client *clnt;
2283 	struct p9_req_t *req;
2284 
2285 	err = 0;
2286 	clnt = fid->clnt;
2287 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2288 
2289 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2290 	if (IS_ERR(req))
2291 		return PTR_ERR(req);
2292 
2293 	err = p9pdu_readf(req->rc, clnt->proto_version, "s", target);
2294 	if (err) {
2295 		trace_9p_protocol_dump(clnt, req->rc);
2296 		goto error;
2297 	}
2298 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2299 error:
2300 	p9_free_req(clnt, req);
2301 	return err;
2302 }
2303 EXPORT_SYMBOL(p9_client_readlink);
2304