xref: /linux/net/9p/client.c (revision 5bdef865eb358b6f3760e25e591ae115e9eeddef)
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 #include <linux/module.h>
27 #include <linux/errno.h>
28 #include <linux/fs.h>
29 #include <linux/poll.h>
30 #include <linux/idr.h>
31 #include <linux/mutex.h>
32 #include <linux/sched.h>
33 #include <linux/uaccess.h>
34 #include <net/9p/9p.h>
35 #include <linux/parser.h>
36 #include <net/9p/client.h>
37 #include <net/9p/transport.h>
38 #include "protocol.h"
39 
40 /*
41   * Client Option Parsing (code inspired by NFS code)
42   *  - a little lazy - parse all client options
43   */
44 
45 enum {
46 	Opt_msize,
47 	Opt_trans,
48 	Opt_legacy,
49 	Opt_err,
50 };
51 
52 static const match_table_t tokens = {
53 	{Opt_msize, "msize=%u"},
54 	{Opt_legacy, "noextend"},
55 	{Opt_trans, "trans=%s"},
56 	{Opt_err, NULL},
57 };
58 
59 static struct p9_req_t *
60 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
61 
62 /**
63  * v9fs_parse_options - parse mount options into session structure
64  * @options: options string passed from mount
65  * @v9ses: existing v9fs session information
66  *
67  * Return 0 upon success, -ERRNO upon failure
68  */
69 
70 static int parse_opts(char *opts, struct p9_client *clnt)
71 {
72 	char *options;
73 	char *p;
74 	substring_t args[MAX_OPT_ARGS];
75 	int option;
76 	int ret = 0;
77 
78 	clnt->dotu = 1;
79 	clnt->msize = 8192;
80 
81 	if (!opts)
82 		return 0;
83 
84 	options = kstrdup(opts, GFP_KERNEL);
85 	if (!options) {
86 		P9_DPRINTK(P9_DEBUG_ERROR,
87 				"failed to allocate copy of option string\n");
88 		return -ENOMEM;
89 	}
90 
91 	while ((p = strsep(&options, ",")) != NULL) {
92 		int token;
93 		if (!*p)
94 			continue;
95 		token = match_token(p, tokens, args);
96 		if (token < Opt_trans) {
97 			int r = match_int(&args[0], &option);
98 			if (r < 0) {
99 				P9_DPRINTK(P9_DEBUG_ERROR,
100 					"integer field, but no integer?\n");
101 				ret = r;
102 				continue;
103 			}
104 		}
105 		switch (token) {
106 		case Opt_msize:
107 			clnt->msize = option;
108 			break;
109 		case Opt_trans:
110 			clnt->trans_mod = v9fs_get_trans_by_name(&args[0]);
111 			break;
112 		case Opt_legacy:
113 			clnt->dotu = 0;
114 			break;
115 		default:
116 			continue;
117 		}
118 	}
119 
120 	kfree(options);
121 	return ret;
122 }
123 
124 /**
125  * p9_tag_alloc - lookup/allocate a request by tag
126  * @c: client session to lookup tag within
127  * @tag: numeric id for transaction
128  *
129  * this is a simple array lookup, but will grow the
130  * request_slots as necessary to accomodate transaction
131  * ids which did not previously have a slot.
132  *
133  * this code relies on the client spinlock to manage locks, its
134  * possible we should switch to something else, but I'd rather
135  * stick with something low-overhead for the common case.
136  *
137  */
138 
139 static struct p9_req_t *p9_tag_alloc(struct p9_client *c, u16 tag)
140 {
141 	unsigned long flags;
142 	int row, col;
143 	struct p9_req_t *req;
144 
145 	/* This looks up the original request by tag so we know which
146 	 * buffer to read the data into */
147 	tag++;
148 
149 	if (tag >= c->max_tag) {
150 		spin_lock_irqsave(&c->lock, flags);
151 		/* check again since original check was outside of lock */
152 		while (tag >= c->max_tag) {
153 			row = (tag / P9_ROW_MAXTAG);
154 			c->reqs[row] = kcalloc(P9_ROW_MAXTAG,
155 					sizeof(struct p9_req_t), GFP_ATOMIC);
156 
157 			if (!c->reqs[row]) {
158 				printk(KERN_ERR "Couldn't grow tag array\n");
159 				spin_unlock_irqrestore(&c->lock, flags);
160 				return ERR_PTR(-ENOMEM);
161 			}
162 			for (col = 0; col < P9_ROW_MAXTAG; col++) {
163 				c->reqs[row][col].status = REQ_STATUS_IDLE;
164 				c->reqs[row][col].tc = NULL;
165 			}
166 			c->max_tag += P9_ROW_MAXTAG;
167 		}
168 		spin_unlock_irqrestore(&c->lock, flags);
169 	}
170 	row = tag / P9_ROW_MAXTAG;
171 	col = tag % P9_ROW_MAXTAG;
172 
173 	req = &c->reqs[row][col];
174 	if (!req->tc) {
175 		req->wq = kmalloc(sizeof(wait_queue_head_t), GFP_KERNEL);
176 		if (!req->wq) {
177 			printk(KERN_ERR "Couldn't grow tag array\n");
178 			return ERR_PTR(-ENOMEM);
179 		}
180 		init_waitqueue_head(req->wq);
181 		req->tc = kmalloc(sizeof(struct p9_fcall)+c->msize,
182 								GFP_KERNEL);
183 		req->rc = kmalloc(sizeof(struct p9_fcall)+c->msize,
184 								GFP_KERNEL);
185 		if ((!req->tc) || (!req->rc)) {
186 			printk(KERN_ERR "Couldn't grow tag array\n");
187 			kfree(req->tc);
188 			kfree(req->rc);
189 			kfree(req->wq);
190 			req->tc = req->rc = NULL;
191 			req->wq = NULL;
192 			return ERR_PTR(-ENOMEM);
193 		}
194 		req->tc->sdata = (char *) req->tc + sizeof(struct p9_fcall);
195 		req->tc->capacity = c->msize;
196 		req->rc->sdata = (char *) req->rc + sizeof(struct p9_fcall);
197 		req->rc->capacity = c->msize;
198 	}
199 
200 	p9pdu_reset(req->tc);
201 	p9pdu_reset(req->rc);
202 
203 	req->tc->tag = tag-1;
204 	req->status = REQ_STATUS_ALLOC;
205 
206 	return &c->reqs[row][col];
207 }
208 
209 /**
210  * p9_tag_lookup - lookup a request by tag
211  * @c: client session to lookup tag within
212  * @tag: numeric id for transaction
213  *
214  */
215 
216 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
217 {
218 	int row, col;
219 
220 	/* This looks up the original request by tag so we know which
221 	 * buffer to read the data into */
222 	tag++;
223 
224 	BUG_ON(tag >= c->max_tag);
225 
226 	row = tag / P9_ROW_MAXTAG;
227 	col = tag % P9_ROW_MAXTAG;
228 
229 	return &c->reqs[row][col];
230 }
231 EXPORT_SYMBOL(p9_tag_lookup);
232 
233 /**
234  * p9_tag_init - setup tags structure and contents
235  * @tags: tags structure from the client struct
236  *
237  * This initializes the tags structure for each client instance.
238  *
239  */
240 
241 static int p9_tag_init(struct p9_client *c)
242 {
243 	int err = 0;
244 
245 	c->tagpool = p9_idpool_create();
246 	if (IS_ERR(c->tagpool)) {
247 		err = PTR_ERR(c->tagpool);
248 		c->tagpool = NULL;
249 		goto error;
250 	}
251 
252 	p9_idpool_get(c->tagpool); /* reserve tag 0 */
253 
254 	c->max_tag = 0;
255 error:
256 	return err;
257 }
258 
259 /**
260  * p9_tag_cleanup - cleans up tags structure and reclaims resources
261  * @tags: tags structure from the client struct
262  *
263  * This frees resources associated with the tags structure
264  *
265  */
266 static void p9_tag_cleanup(struct p9_client *c)
267 {
268 	int row, col;
269 
270 	/* check to insure all requests are idle */
271 	for (row = 0; row < (c->max_tag/P9_ROW_MAXTAG); row++) {
272 		for (col = 0; col < P9_ROW_MAXTAG; col++) {
273 			if (c->reqs[row][col].status != REQ_STATUS_IDLE) {
274 				P9_DPRINTK(P9_DEBUG_MUX,
275 				  "Attempting to cleanup non-free tag %d,%d\n",
276 				  row, col);
277 				/* TODO: delay execution of cleanup */
278 				return;
279 			}
280 		}
281 	}
282 
283 	if (c->tagpool)
284 		p9_idpool_destroy(c->tagpool);
285 
286 	/* free requests associated with tags */
287 	for (row = 0; row < (c->max_tag/P9_ROW_MAXTAG); row++) {
288 		for (col = 0; col < P9_ROW_MAXTAG; col++) {
289 			kfree(c->reqs[row][col].wq);
290 			kfree(c->reqs[row][col].tc);
291 			kfree(c->reqs[row][col].rc);
292 		}
293 		kfree(c->reqs[row]);
294 	}
295 	c->max_tag = 0;
296 }
297 
298 /**
299  * p9_free_req - free a request and clean-up as necessary
300  * c: client state
301  * r: request to release
302  *
303  */
304 
305 static void p9_free_req(struct p9_client *c, struct p9_req_t *r)
306 {
307 	int tag = r->tc->tag;
308 	P9_DPRINTK(P9_DEBUG_MUX, "clnt %p req %p tag: %d\n", c, r, tag);
309 
310 	r->status = REQ_STATUS_IDLE;
311 	if (tag != P9_NOTAG && p9_idpool_check(tag, c->tagpool))
312 		p9_idpool_put(tag, c->tagpool);
313 }
314 
315 /**
316  * p9_client_cb - call back from transport to client
317  * c: client state
318  * req: request received
319  *
320  */
321 void p9_client_cb(struct p9_client *c, struct p9_req_t *req)
322 {
323 	P9_DPRINTK(P9_DEBUG_MUX, " tag %d\n", req->tc->tag);
324 	wake_up(req->wq);
325 	P9_DPRINTK(P9_DEBUG_MUX, "wakeup: %d\n", req->tc->tag);
326 }
327 EXPORT_SYMBOL(p9_client_cb);
328 
329 /**
330  * p9_parse_header - parse header arguments out of a packet
331  * @pdu: packet to parse
332  * @size: size of packet
333  * @type: type of request
334  * @tag: tag of packet
335  * @rewind: set if we need to rewind offset afterwards
336  */
337 
338 int
339 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type, int16_t *tag,
340 								int rewind)
341 {
342 	int8_t r_type;
343 	int16_t r_tag;
344 	int32_t r_size;
345 	int offset = pdu->offset;
346 	int err;
347 
348 	pdu->offset = 0;
349 	if (pdu->size == 0)
350 		pdu->size = 7;
351 
352 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
353 	if (err)
354 		goto rewind_and_exit;
355 
356 	pdu->size = r_size;
357 	pdu->id = r_type;
358 	pdu->tag = r_tag;
359 
360 	P9_DPRINTK(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n", pdu->size,
361 							pdu->id, pdu->tag);
362 
363 	if (type)
364 		*type = r_type;
365 	if (tag)
366 		*tag = r_tag;
367 	if (size)
368 		*size = r_size;
369 
370 
371 rewind_and_exit:
372 	if (rewind)
373 		pdu->offset = offset;
374 	return err;
375 }
376 EXPORT_SYMBOL(p9_parse_header);
377 
378 /**
379  * p9_check_errors - check 9p packet for error return and process it
380  * @c: current client instance
381  * @req: request to parse and check for error conditions
382  *
383  * returns error code if one is discovered, otherwise returns 0
384  *
385  * this will have to be more complicated if we have multiple
386  * error packet types
387  */
388 
389 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
390 {
391 	int8_t type;
392 	int err;
393 
394 	err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
395 	if (err) {
396 		P9_DPRINTK(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
397 		return err;
398 	}
399 
400 	if (type == P9_RERROR) {
401 		int ecode;
402 		char *ename;
403 
404 		err = p9pdu_readf(req->rc, c->dotu, "s?d", &ename, &ecode);
405 		if (err) {
406 			P9_DPRINTK(P9_DEBUG_ERROR, "couldn't parse error%d\n",
407 									err);
408 			return err;
409 		}
410 
411 		if (c->dotu)
412 			err = -ecode;
413 
414 		if (!err) {
415 			err = p9_errstr2errno(ename, strlen(ename));
416 
417 			/* string match failed */
418 			if (!err)
419 				err = -ESERVERFAULT;
420 		}
421 
422 		P9_DPRINTK(P9_DEBUG_9P, "<<< RERROR (%d) %s\n", -ecode, ename);
423 
424 		kfree(ename);
425 	} else
426 		err = 0;
427 
428 	return err;
429 }
430 
431 /**
432  * p9_client_flush - flush (cancel) a request
433  * c: client state
434  * req: request to cancel
435  *
436  * This sents a flush for a particular requests and links
437  * the flush request to the original request.  The current
438  * code only supports a single flush request although the protocol
439  * allows for multiple flush requests to be sent for a single request.
440  *
441  */
442 
443 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
444 {
445 	struct p9_req_t *req;
446 	int16_t oldtag;
447 	int err;
448 
449 	err = p9_parse_header(oldreq->tc, NULL, NULL, &oldtag, 1);
450 	if (err)
451 		return err;
452 
453 	P9_DPRINTK(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
454 
455 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
456 	if (IS_ERR(req))
457 		return PTR_ERR(req);
458 
459 
460 	/* if we haven't received a response for oldreq,
461 	   remove it from the list. */
462 	spin_lock(&c->lock);
463 	if (oldreq->status == REQ_STATUS_FLSH)
464 		list_del(&oldreq->req_list);
465 	spin_unlock(&c->lock);
466 
467 	p9_free_req(c, req);
468 	return 0;
469 }
470 
471 /**
472  * p9_client_rpc - issue a request and wait for a response
473  * @c: client session
474  * @type: type of request
475  * @fmt: protocol format string (see protocol.c)
476  *
477  * Returns request structure (which client must free using p9_free_req)
478  */
479 
480 static struct p9_req_t *
481 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
482 {
483 	va_list ap;
484 	int tag, err;
485 	struct p9_req_t *req;
486 	unsigned long flags;
487 	int sigpending;
488 
489 	P9_DPRINTK(P9_DEBUG_MUX, "client %p op %d\n", c, type);
490 
491 	if (c->status != Connected)
492 		return ERR_PTR(-EIO);
493 
494 	if (signal_pending(current)) {
495 		sigpending = 1;
496 		clear_thread_flag(TIF_SIGPENDING);
497 	} else
498 		sigpending = 0;
499 
500 	tag = P9_NOTAG;
501 	if (type != P9_TVERSION) {
502 		tag = p9_idpool_get(c->tagpool);
503 		if (tag < 0)
504 			return ERR_PTR(-ENOMEM);
505 	}
506 
507 	req = p9_tag_alloc(c, tag);
508 	if (IS_ERR(req))
509 		return req;
510 
511 	/* marshall the data */
512 	p9pdu_prepare(req->tc, tag, type);
513 	va_start(ap, fmt);
514 	err = p9pdu_vwritef(req->tc, c->dotu, fmt, ap);
515 	va_end(ap);
516 	p9pdu_finalize(req->tc);
517 
518 	err = c->trans_mod->request(c, req);
519 	if (err < 0) {
520 		c->status = Disconnected;
521 		goto reterr;
522 	}
523 
524 	P9_DPRINTK(P9_DEBUG_MUX, "wait %p tag: %d\n", req->wq, tag);
525 	err = wait_event_interruptible(*req->wq,
526 						req->status >= REQ_STATUS_RCVD);
527 	P9_DPRINTK(P9_DEBUG_MUX, "wait %p tag: %d returned %d\n",
528 						req->wq, tag, err);
529 
530 	if (req->status == REQ_STATUS_ERROR) {
531 		P9_DPRINTK(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
532 		err = req->t_err;
533 	}
534 
535 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
536 		P9_DPRINTK(P9_DEBUG_MUX, "flushing\n");
537 		sigpending = 1;
538 		clear_thread_flag(TIF_SIGPENDING);
539 
540 		if (c->trans_mod->cancel(c, req))
541 			p9_client_flush(c, req);
542 
543 		/* if we received the response anyway, don't signal error */
544 		if (req->status == REQ_STATUS_RCVD)
545 			err = 0;
546 	}
547 
548 	if (sigpending) {
549 		spin_lock_irqsave(&current->sighand->siglock, flags);
550 		recalc_sigpending();
551 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
552 	}
553 
554 	if (err < 0)
555 		goto reterr;
556 
557 	err = p9_check_errors(c, req);
558 	if (!err) {
559 		P9_DPRINTK(P9_DEBUG_MUX, "exit: client %p op %d\n", c, type);
560 		return req;
561 	}
562 
563 reterr:
564 	P9_DPRINTK(P9_DEBUG_MUX, "exit: client %p op %d error: %d\n", c, type,
565 									err);
566 	p9_free_req(c, req);
567 	return ERR_PTR(err);
568 }
569 
570 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
571 {
572 	int ret;
573 	struct p9_fid *fid;
574 	unsigned long flags;
575 
576 	P9_DPRINTK(P9_DEBUG_FID, "clnt %p\n", clnt);
577 	fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
578 	if (!fid)
579 		return ERR_PTR(-ENOMEM);
580 
581 	ret = p9_idpool_get(clnt->fidpool);
582 	if (ret < 0) {
583 		ret = -ENOSPC;
584 		goto error;
585 	}
586 	fid->fid = ret;
587 
588 	memset(&fid->qid, 0, sizeof(struct p9_qid));
589 	fid->mode = -1;
590 	fid->rdir_fpos = 0;
591 	fid->uid = current_fsuid();
592 	fid->clnt = clnt;
593 	fid->aux = NULL;
594 
595 	spin_lock_irqsave(&clnt->lock, flags);
596 	list_add(&fid->flist, &clnt->fidlist);
597 	spin_unlock_irqrestore(&clnt->lock, flags);
598 
599 	return fid;
600 
601 error:
602 	kfree(fid);
603 	return ERR_PTR(ret);
604 }
605 
606 static void p9_fid_destroy(struct p9_fid *fid)
607 {
608 	struct p9_client *clnt;
609 	unsigned long flags;
610 
611 	P9_DPRINTK(P9_DEBUG_FID, "fid %d\n", fid->fid);
612 	clnt = fid->clnt;
613 	p9_idpool_put(fid->fid, clnt->fidpool);
614 	spin_lock_irqsave(&clnt->lock, flags);
615 	list_del(&fid->flist);
616 	spin_unlock_irqrestore(&clnt->lock, flags);
617 	kfree(fid);
618 }
619 
620 int p9_client_version(struct p9_client *c)
621 {
622 	int err = 0;
623 	struct p9_req_t *req;
624 	char *version;
625 	int msize;
626 
627 	P9_DPRINTK(P9_DEBUG_9P, ">>> TVERSION msize %d extended %d\n",
628 							c->msize, c->dotu);
629 	req = p9_client_rpc(c, P9_TVERSION, "ds", c->msize,
630 				c->dotu ? "9P2000.u" : "9P2000");
631 	if (IS_ERR(req))
632 		return PTR_ERR(req);
633 
634 	err = p9pdu_readf(req->rc, c->dotu, "ds", &msize, &version);
635 	if (err) {
636 		P9_DPRINTK(P9_DEBUG_9P, "version error %d\n", err);
637 		p9pdu_dump(1, req->rc);
638 		goto error;
639 	}
640 
641 	P9_DPRINTK(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
642 	if (!memcmp(version, "9P2000.u", 8))
643 		c->dotu = 1;
644 	else if (!memcmp(version, "9P2000", 6))
645 		c->dotu = 0;
646 	else {
647 		err = -EREMOTEIO;
648 		goto error;
649 	}
650 
651 	if (msize < c->msize)
652 		c->msize = msize;
653 
654 error:
655 	kfree(version);
656 	p9_free_req(c, req);
657 
658 	return err;
659 }
660 EXPORT_SYMBOL(p9_client_version);
661 
662 struct p9_client *p9_client_create(const char *dev_name, char *options)
663 {
664 	int err;
665 	struct p9_client *clnt;
666 
667 	err = 0;
668 	clnt = kmalloc(sizeof(struct p9_client), GFP_KERNEL);
669 	if (!clnt)
670 		return ERR_PTR(-ENOMEM);
671 
672 	clnt->trans_mod = NULL;
673 	clnt->trans = NULL;
674 	spin_lock_init(&clnt->lock);
675 	INIT_LIST_HEAD(&clnt->fidlist);
676 	clnt->fidpool = p9_idpool_create();
677 	if (IS_ERR(clnt->fidpool)) {
678 		err = PTR_ERR(clnt->fidpool);
679 		clnt->fidpool = NULL;
680 		goto error;
681 	}
682 
683 	p9_tag_init(clnt);
684 
685 	err = parse_opts(options, clnt);
686 	if (err < 0)
687 		goto error;
688 
689 	if (!clnt->trans_mod)
690 		clnt->trans_mod = v9fs_get_default_trans();
691 
692 	if (clnt->trans_mod == NULL) {
693 		err = -EPROTONOSUPPORT;
694 		P9_DPRINTK(P9_DEBUG_ERROR,
695 				"No transport defined or default transport\n");
696 		goto error;
697 	}
698 
699 	P9_DPRINTK(P9_DEBUG_MUX, "clnt %p trans %p msize %d dotu %d\n",
700 		clnt, clnt->trans_mod, clnt->msize, clnt->dotu);
701 
702 	err = clnt->trans_mod->create(clnt, dev_name, options);
703 	if (err)
704 		goto error;
705 
706 	if ((clnt->msize+P9_IOHDRSZ) > clnt->trans_mod->maxsize)
707 		clnt->msize = clnt->trans_mod->maxsize-P9_IOHDRSZ;
708 
709 	err = p9_client_version(clnt);
710 	if (err)
711 		goto error;
712 
713 	return clnt;
714 
715 error:
716 	p9_client_destroy(clnt);
717 	return ERR_PTR(err);
718 }
719 EXPORT_SYMBOL(p9_client_create);
720 
721 void p9_client_destroy(struct p9_client *clnt)
722 {
723 	struct p9_fid *fid, *fidptr;
724 
725 	P9_DPRINTK(P9_DEBUG_MUX, "clnt %p\n", clnt);
726 
727 	if (clnt->trans_mod)
728 		clnt->trans_mod->close(clnt);
729 
730 	v9fs_put_trans(clnt->trans_mod);
731 
732 	list_for_each_entry_safe(fid, fidptr, &clnt->fidlist, flist)
733 		p9_fid_destroy(fid);
734 
735 	if (clnt->fidpool)
736 		p9_idpool_destroy(clnt->fidpool);
737 
738 	p9_tag_cleanup(clnt);
739 
740 	kfree(clnt);
741 }
742 EXPORT_SYMBOL(p9_client_destroy);
743 
744 void p9_client_disconnect(struct p9_client *clnt)
745 {
746 	P9_DPRINTK(P9_DEBUG_9P, "clnt %p\n", clnt);
747 	clnt->status = Disconnected;
748 }
749 EXPORT_SYMBOL(p9_client_disconnect);
750 
751 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
752 	char *uname, u32 n_uname, char *aname)
753 {
754 	int err;
755 	struct p9_req_t *req;
756 	struct p9_fid *fid;
757 	struct p9_qid qid;
758 
759 	P9_DPRINTK(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
760 					afid ? afid->fid : -1, uname, aname);
761 	err = 0;
762 
763 	fid = p9_fid_create(clnt);
764 	if (IS_ERR(fid)) {
765 		err = PTR_ERR(fid);
766 		fid = NULL;
767 		goto error;
768 	}
769 
770 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?d", fid->fid,
771 			afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
772 	if (IS_ERR(req)) {
773 		err = PTR_ERR(req);
774 		goto error;
775 	}
776 
777 	err = p9pdu_readf(req->rc, clnt->dotu, "Q", &qid);
778 	if (err) {
779 		p9pdu_dump(1, req->rc);
780 		p9_free_req(clnt, req);
781 		goto error;
782 	}
783 
784 	P9_DPRINTK(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
785 					qid.type,
786 					(unsigned long long)qid.path,
787 					qid.version);
788 
789 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
790 
791 	p9_free_req(clnt, req);
792 	return fid;
793 
794 error:
795 	if (fid)
796 		p9_fid_destroy(fid);
797 	return ERR_PTR(err);
798 }
799 EXPORT_SYMBOL(p9_client_attach);
800 
801 struct p9_fid *
802 p9_client_auth(struct p9_client *clnt, char *uname, u32 n_uname, char *aname)
803 {
804 	int err;
805 	struct p9_req_t *req;
806 	struct p9_qid qid;
807 	struct p9_fid *afid;
808 
809 	P9_DPRINTK(P9_DEBUG_9P, ">>> TAUTH uname %s aname %s\n", uname, aname);
810 	err = 0;
811 
812 	afid = p9_fid_create(clnt);
813 	if (IS_ERR(afid)) {
814 		err = PTR_ERR(afid);
815 		afid = NULL;
816 		goto error;
817 	}
818 
819 	req = p9_client_rpc(clnt, P9_TAUTH, "dss?d",
820 			afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
821 	if (IS_ERR(req)) {
822 		err = PTR_ERR(req);
823 		goto error;
824 	}
825 
826 	err = p9pdu_readf(req->rc, clnt->dotu, "Q", &qid);
827 	if (err) {
828 		p9pdu_dump(1, req->rc);
829 		p9_free_req(clnt, req);
830 		goto error;
831 	}
832 
833 	P9_DPRINTK(P9_DEBUG_9P, "<<< RAUTH qid %x.%llx.%x\n",
834 					qid.type,
835 					(unsigned long long)qid.path,
836 					qid.version);
837 
838 	memmove(&afid->qid, &qid, sizeof(struct p9_qid));
839 	p9_free_req(clnt, req);
840 	return afid;
841 
842 error:
843 	if (afid)
844 		p9_fid_destroy(afid);
845 	return ERR_PTR(err);
846 }
847 EXPORT_SYMBOL(p9_client_auth);
848 
849 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, int nwname, char **wnames,
850 	int clone)
851 {
852 	int err;
853 	struct p9_client *clnt;
854 	struct p9_fid *fid;
855 	struct p9_qid *wqids;
856 	struct p9_req_t *req;
857 	int16_t nwqids, count;
858 
859 	err = 0;
860 	clnt = oldfid->clnt;
861 	if (clone) {
862 		fid = p9_fid_create(clnt);
863 		if (IS_ERR(fid)) {
864 			err = PTR_ERR(fid);
865 			fid = NULL;
866 			goto error;
867 		}
868 
869 		fid->uid = oldfid->uid;
870 	} else
871 		fid = oldfid;
872 
873 
874 	P9_DPRINTK(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %d wname[0] %s\n",
875 		oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
876 
877 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
878 								nwname, wnames);
879 	if (IS_ERR(req)) {
880 		err = PTR_ERR(req);
881 		goto error;
882 	}
883 
884 	err = p9pdu_readf(req->rc, clnt->dotu, "R", &nwqids, &wqids);
885 	if (err) {
886 		p9pdu_dump(1, req->rc);
887 		p9_free_req(clnt, req);
888 		goto clunk_fid;
889 	}
890 	p9_free_req(clnt, req);
891 
892 	P9_DPRINTK(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
893 
894 	if (nwqids != nwname) {
895 		err = -ENOENT;
896 		goto clunk_fid;
897 	}
898 
899 	for (count = 0; count < nwqids; count++)
900 		P9_DPRINTK(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
901 			count, wqids[count].type,
902 			(unsigned long long)wqids[count].path,
903 			wqids[count].version);
904 
905 	if (nwname)
906 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
907 	else
908 		fid->qid = oldfid->qid;
909 
910 	return fid;
911 
912 clunk_fid:
913 	p9_client_clunk(fid);
914 	fid = NULL;
915 
916 error:
917 	if (fid && (fid != oldfid))
918 		p9_fid_destroy(fid);
919 
920 	return ERR_PTR(err);
921 }
922 EXPORT_SYMBOL(p9_client_walk);
923 
924 int p9_client_open(struct p9_fid *fid, int mode)
925 {
926 	int err;
927 	struct p9_client *clnt;
928 	struct p9_req_t *req;
929 	struct p9_qid qid;
930 	int iounit;
931 
932 	P9_DPRINTK(P9_DEBUG_9P, ">>> TOPEN fid %d mode %d\n", fid->fid, mode);
933 	err = 0;
934 	clnt = fid->clnt;
935 
936 	if (fid->mode != -1)
937 		return -EINVAL;
938 
939 	req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
940 	if (IS_ERR(req)) {
941 		err = PTR_ERR(req);
942 		goto error;
943 	}
944 
945 	err = p9pdu_readf(req->rc, clnt->dotu, "Qd", &qid, &iounit);
946 	if (err) {
947 		p9pdu_dump(1, req->rc);
948 		goto free_and_error;
949 	}
950 
951 	P9_DPRINTK(P9_DEBUG_9P, "<<< ROPEN qid %x.%llx.%x iounit %x\n",
952 				qid.type,
953 				(unsigned long long)qid.path,
954 				qid.version, iounit);
955 
956 	fid->mode = mode;
957 	fid->iounit = iounit;
958 
959 free_and_error:
960 	p9_free_req(clnt, req);
961 error:
962 	return err;
963 }
964 EXPORT_SYMBOL(p9_client_open);
965 
966 int p9_client_fcreate(struct p9_fid *fid, char *name, u32 perm, int mode,
967 		     char *extension)
968 {
969 	int err;
970 	struct p9_client *clnt;
971 	struct p9_req_t *req;
972 	struct p9_qid qid;
973 	int iounit;
974 
975 	P9_DPRINTK(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
976 						fid->fid, name, perm, mode);
977 	err = 0;
978 	clnt = fid->clnt;
979 
980 	if (fid->mode != -1)
981 		return -EINVAL;
982 
983 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
984 				mode, extension);
985 	if (IS_ERR(req)) {
986 		err = PTR_ERR(req);
987 		goto error;
988 	}
989 
990 	err = p9pdu_readf(req->rc, clnt->dotu, "Qd", &qid, &iounit);
991 	if (err) {
992 		p9pdu_dump(1, req->rc);
993 		goto free_and_error;
994 	}
995 
996 	P9_DPRINTK(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
997 				qid.type,
998 				(unsigned long long)qid.path,
999 				qid.version, iounit);
1000 
1001 	fid->mode = mode;
1002 	fid->iounit = iounit;
1003 
1004 free_and_error:
1005 	p9_free_req(clnt, req);
1006 error:
1007 	return err;
1008 }
1009 EXPORT_SYMBOL(p9_client_fcreate);
1010 
1011 int p9_client_clunk(struct p9_fid *fid)
1012 {
1013 	int err;
1014 	struct p9_client *clnt;
1015 	struct p9_req_t *req;
1016 
1017 	P9_DPRINTK(P9_DEBUG_9P, ">>> TCLUNK fid %d\n", fid->fid);
1018 	err = 0;
1019 	clnt = fid->clnt;
1020 
1021 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1022 	if (IS_ERR(req)) {
1023 		err = PTR_ERR(req);
1024 		goto error;
1025 	}
1026 
1027 	P9_DPRINTK(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1028 
1029 	p9_free_req(clnt, req);
1030 	p9_fid_destroy(fid);
1031 
1032 error:
1033 	return err;
1034 }
1035 EXPORT_SYMBOL(p9_client_clunk);
1036 
1037 int p9_client_remove(struct p9_fid *fid)
1038 {
1039 	int err;
1040 	struct p9_client *clnt;
1041 	struct p9_req_t *req;
1042 
1043 	P9_DPRINTK(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1044 	err = 0;
1045 	clnt = fid->clnt;
1046 
1047 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1048 	if (IS_ERR(req)) {
1049 		err = PTR_ERR(req);
1050 		goto error;
1051 	}
1052 
1053 	P9_DPRINTK(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1054 
1055 	p9_free_req(clnt, req);
1056 	p9_fid_destroy(fid);
1057 
1058 error:
1059 	return err;
1060 }
1061 EXPORT_SYMBOL(p9_client_remove);
1062 
1063 int
1064 p9_client_read(struct p9_fid *fid, char *data, char __user *udata, u64 offset,
1065 								u32 count)
1066 {
1067 	int err, rsize, total;
1068 	struct p9_client *clnt;
1069 	struct p9_req_t *req;
1070 	char *dataptr;
1071 
1072 	P9_DPRINTK(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n", fid->fid,
1073 					(long long unsigned) offset, count);
1074 	err = 0;
1075 	clnt = fid->clnt;
1076 	total = 0;
1077 
1078 	rsize = fid->iounit;
1079 	if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1080 		rsize = clnt->msize - P9_IOHDRSZ;
1081 
1082 	if (count < rsize)
1083 		rsize = count;
1084 
1085 	req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset, rsize);
1086 	if (IS_ERR(req)) {
1087 		err = PTR_ERR(req);
1088 		goto error;
1089 	}
1090 
1091 	err = p9pdu_readf(req->rc, clnt->dotu, "D", &count, &dataptr);
1092 	if (err) {
1093 		p9pdu_dump(1, req->rc);
1094 		goto free_and_error;
1095 	}
1096 
1097 	P9_DPRINTK(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1098 
1099 	if (data) {
1100 		memmove(data, dataptr, count);
1101 	}
1102 
1103 	if (udata) {
1104 		err = copy_to_user(udata, dataptr, count);
1105 		if (err) {
1106 			err = -EFAULT;
1107 			goto free_and_error;
1108 		}
1109 	}
1110 
1111 	p9_free_req(clnt, req);
1112 	return count;
1113 
1114 free_and_error:
1115 	p9_free_req(clnt, req);
1116 error:
1117 	return err;
1118 }
1119 EXPORT_SYMBOL(p9_client_read);
1120 
1121 int
1122 p9_client_write(struct p9_fid *fid, char *data, const char __user *udata,
1123 							u64 offset, u32 count)
1124 {
1125 	int err, rsize, total;
1126 	struct p9_client *clnt;
1127 	struct p9_req_t *req;
1128 
1129 	P9_DPRINTK(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %d\n",
1130 				fid->fid, (long long unsigned) offset, count);
1131 	err = 0;
1132 	clnt = fid->clnt;
1133 	total = 0;
1134 
1135 	rsize = fid->iounit;
1136 	if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1137 		rsize = clnt->msize - P9_IOHDRSZ;
1138 
1139 	if (count < rsize)
1140 		rsize = count;
1141 	if (data)
1142 		req = p9_client_rpc(clnt, P9_TWRITE, "dqD", fid->fid, offset,
1143 								rsize, data);
1144 	else
1145 		req = p9_client_rpc(clnt, P9_TWRITE, "dqU", fid->fid, offset,
1146 								rsize, udata);
1147 	if (IS_ERR(req)) {
1148 		err = PTR_ERR(req);
1149 		goto error;
1150 	}
1151 
1152 	err = p9pdu_readf(req->rc, clnt->dotu, "d", &count);
1153 	if (err) {
1154 		p9pdu_dump(1, req->rc);
1155 		goto free_and_error;
1156 	}
1157 
1158 	P9_DPRINTK(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1159 
1160 	p9_free_req(clnt, req);
1161 	return count;
1162 
1163 free_and_error:
1164 	p9_free_req(clnt, req);
1165 error:
1166 	return err;
1167 }
1168 EXPORT_SYMBOL(p9_client_write);
1169 
1170 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1171 {
1172 	int err;
1173 	struct p9_client *clnt;
1174 	struct p9_wstat *ret = kmalloc(sizeof(struct p9_wstat), GFP_KERNEL);
1175 	struct p9_req_t *req;
1176 	u16 ignored;
1177 
1178 	P9_DPRINTK(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1179 
1180 	if (!ret)
1181 		return ERR_PTR(-ENOMEM);
1182 
1183 	err = 0;
1184 	clnt = fid->clnt;
1185 
1186 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1187 	if (IS_ERR(req)) {
1188 		err = PTR_ERR(req);
1189 		goto error;
1190 	}
1191 
1192 	err = p9pdu_readf(req->rc, clnt->dotu, "wS", &ignored, ret);
1193 	if (err) {
1194 		p9pdu_dump(1, req->rc);
1195 		p9_free_req(clnt, req);
1196 		goto error;
1197 	}
1198 
1199 	P9_DPRINTK(P9_DEBUG_9P,
1200 		"<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1201 		"<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1202 		"<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1203 		"<<<    uid=%d gid=%d n_muid=%d\n",
1204 		ret->size, ret->type, ret->dev, ret->qid.type,
1205 		(unsigned long long)ret->qid.path, ret->qid.version, ret->mode,
1206 		ret->atime, ret->mtime, (unsigned long long)ret->length,
1207 		ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1208 		ret->n_uid, ret->n_gid, ret->n_muid);
1209 
1210 	p9_free_req(clnt, req);
1211 	return ret;
1212 
1213 error:
1214 	kfree(ret);
1215 	return ERR_PTR(err);
1216 }
1217 EXPORT_SYMBOL(p9_client_stat);
1218 
1219 static int p9_client_statsize(struct p9_wstat *wst, int optional)
1220 {
1221 	int ret;
1222 
1223 	/* size[2] type[2] dev[4] qid[13] */
1224 	/* mode[4] atime[4] mtime[4] length[8]*/
1225 	/* name[s] uid[s] gid[s] muid[s] */
1226 	ret = 2+2+4+13+4+4+4+8+2+2+2+2;
1227 
1228 	if (wst->name)
1229 		ret += strlen(wst->name);
1230 	if (wst->uid)
1231 		ret += strlen(wst->uid);
1232 	if (wst->gid)
1233 		ret += strlen(wst->gid);
1234 	if (wst->muid)
1235 		ret += strlen(wst->muid);
1236 
1237 	if (optional) {
1238 		ret += 2+4+4+4;	/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1239 		if (wst->extension)
1240 			ret += strlen(wst->extension);
1241 	}
1242 
1243 	return ret;
1244 }
1245 
1246 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1247 {
1248 	int err;
1249 	struct p9_req_t *req;
1250 	struct p9_client *clnt;
1251 
1252 	err = 0;
1253 	clnt = fid->clnt;
1254 	wst->size = p9_client_statsize(wst, clnt->dotu);
1255 	P9_DPRINTK(P9_DEBUG_9P, ">>> TWSTAT fid %d\n", fid->fid);
1256 	P9_DPRINTK(P9_DEBUG_9P,
1257 		"     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1258 		"     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1259 		"     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1260 		"     uid=%d gid=%d n_muid=%d\n",
1261 		wst->size, wst->type, wst->dev, wst->qid.type,
1262 		(unsigned long long)wst->qid.path, wst->qid.version, wst->mode,
1263 		wst->atime, wst->mtime, (unsigned long long)wst->length,
1264 		wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1265 		wst->n_uid, wst->n_gid, wst->n_muid);
1266 
1267 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS", fid->fid, wst->size, wst);
1268 	if (IS_ERR(req)) {
1269 		err = PTR_ERR(req);
1270 		goto error;
1271 	}
1272 
1273 	P9_DPRINTK(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1274 
1275 	p9_free_req(clnt, req);
1276 error:
1277 	return err;
1278 }
1279 EXPORT_SYMBOL(p9_client_wstat);
1280