xref: /openbmc/linux/net/9p/client.c (revision dd5b2498)
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 			if (option < 4096) {
185 				p9_debug(P9_DEBUG_ERROR,
186 					 "msize should be at least 4k\n");
187 				ret = -EINVAL;
188 				continue;
189 			}
190 			clnt->msize = option;
191 			break;
192 		case Opt_trans:
193 			s = match_strdup(&args[0]);
194 			if (!s) {
195 				ret = -ENOMEM;
196 				p9_debug(P9_DEBUG_ERROR,
197 					 "problem allocating copy of trans arg\n");
198 				goto free_and_return;
199 			}
200 
201 			v9fs_put_trans(clnt->trans_mod);
202 			clnt->trans_mod = v9fs_get_trans_by_name(s);
203 			if (clnt->trans_mod == NULL) {
204 				pr_info("Could not find request transport: %s\n",
205 					s);
206 				ret = -EINVAL;
207 			}
208 			kfree(s);
209 			break;
210 		case Opt_legacy:
211 			clnt->proto_version = p9_proto_legacy;
212 			break;
213 		case Opt_version:
214 			s = match_strdup(&args[0]);
215 			if (!s) {
216 				ret = -ENOMEM;
217 				p9_debug(P9_DEBUG_ERROR,
218 					 "problem allocating copy of version arg\n");
219 				goto free_and_return;
220 			}
221 			r = get_protocol_version(s);
222 			if (r < 0)
223 				ret = r;
224 			else
225 				clnt->proto_version = r;
226 			kfree(s);
227 			break;
228 		default:
229 			continue;
230 		}
231 	}
232 
233 free_and_return:
234 	if (ret)
235 		v9fs_put_trans(clnt->trans_mod);
236 	kfree(tmp_options);
237 	return ret;
238 }
239 
240 static int p9_fcall_init(struct p9_client *c, struct p9_fcall *fc,
241 			 int alloc_msize)
242 {
243 	if (likely(c->fcall_cache) && alloc_msize == c->msize) {
244 		fc->sdata = kmem_cache_alloc(c->fcall_cache, GFP_NOFS);
245 		fc->cache = c->fcall_cache;
246 	} else {
247 		fc->sdata = kmalloc(alloc_msize, GFP_NOFS);
248 		fc->cache = NULL;
249 	}
250 	if (!fc->sdata)
251 		return -ENOMEM;
252 	fc->capacity = alloc_msize;
253 	return 0;
254 }
255 
256 void p9_fcall_fini(struct p9_fcall *fc)
257 {
258 	/* sdata can be NULL for interrupted requests in trans_rdma,
259 	 * and kmem_cache_free does not do NULL-check for us
260 	 */
261 	if (unlikely(!fc->sdata))
262 		return;
263 
264 	if (fc->cache)
265 		kmem_cache_free(fc->cache, fc->sdata);
266 	else
267 		kfree(fc->sdata);
268 }
269 EXPORT_SYMBOL(p9_fcall_fini);
270 
271 static struct kmem_cache *p9_req_cache;
272 
273 /**
274  * p9_req_alloc - Allocate a new request.
275  * @c: Client session.
276  * @type: Transaction type.
277  * @max_size: Maximum packet size for this request.
278  *
279  * Context: Process context.
280  * Return: Pointer to new request.
281  */
282 static struct p9_req_t *
283 p9_tag_alloc(struct p9_client *c, int8_t type, unsigned int max_size)
284 {
285 	struct p9_req_t *req = kmem_cache_alloc(p9_req_cache, GFP_NOFS);
286 	int alloc_msize = min(c->msize, max_size);
287 	int tag;
288 
289 	if (!req)
290 		return ERR_PTR(-ENOMEM);
291 
292 	if (p9_fcall_init(c, &req->tc, alloc_msize))
293 		goto free_req;
294 	if (p9_fcall_init(c, &req->rc, alloc_msize))
295 		goto free;
296 
297 	p9pdu_reset(&req->tc);
298 	p9pdu_reset(&req->rc);
299 	req->status = REQ_STATUS_ALLOC;
300 	init_waitqueue_head(&req->wq);
301 	INIT_LIST_HEAD(&req->req_list);
302 
303 	idr_preload(GFP_NOFS);
304 	spin_lock_irq(&c->lock);
305 	if (type == P9_TVERSION)
306 		tag = idr_alloc(&c->reqs, req, P9_NOTAG, P9_NOTAG + 1,
307 				GFP_NOWAIT);
308 	else
309 		tag = idr_alloc(&c->reqs, req, 0, P9_NOTAG, GFP_NOWAIT);
310 	req->tc.tag = tag;
311 	spin_unlock_irq(&c->lock);
312 	idr_preload_end();
313 	if (tag < 0)
314 		goto free;
315 
316 	/* Init ref to two because in the general case there is one ref
317 	 * that is put asynchronously by a writer thread, one ref
318 	 * temporarily given by p9_tag_lookup and put by p9_client_cb
319 	 * in the recv thread, and one ref put by p9_tag_remove in the
320 	 * main thread. The only exception is virtio that does not use
321 	 * p9_tag_lookup but does not have a writer thread either
322 	 * (the write happens synchronously in the request/zc_request
323 	 * callback), so p9_client_cb eats the second ref there
324 	 * as the pointer is duplicated directly by virtqueue_add_sgs()
325 	 */
326 	refcount_set(&req->refcount.refcount, 2);
327 
328 	return req;
329 
330 free:
331 	p9_fcall_fini(&req->tc);
332 	p9_fcall_fini(&req->rc);
333 free_req:
334 	kmem_cache_free(p9_req_cache, req);
335 	return ERR_PTR(-ENOMEM);
336 }
337 
338 /**
339  * p9_tag_lookup - Look up a request by tag.
340  * @c: Client session.
341  * @tag: Transaction ID.
342  *
343  * Context: Any context.
344  * Return: A request, or %NULL if there is no request with that tag.
345  */
346 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
347 {
348 	struct p9_req_t *req;
349 
350 	rcu_read_lock();
351 again:
352 	req = idr_find(&c->reqs, tag);
353 	if (req) {
354 		/* We have to be careful with the req found under rcu_read_lock
355 		 * Thanks to SLAB_TYPESAFE_BY_RCU we can safely try to get the
356 		 * ref again without corrupting other data, then check again
357 		 * that the tag matches once we have the ref
358 		 */
359 		if (!p9_req_try_get(req))
360 			goto again;
361 		if (req->tc.tag != tag) {
362 			p9_req_put(req);
363 			goto again;
364 		}
365 	}
366 	rcu_read_unlock();
367 
368 	return req;
369 }
370 EXPORT_SYMBOL(p9_tag_lookup);
371 
372 /**
373  * p9_tag_remove - Remove a tag.
374  * @c: Client session.
375  * @r: Request of reference.
376  *
377  * Context: Any context.
378  */
379 static int p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
380 {
381 	unsigned long flags;
382 	u16 tag = r->tc.tag;
383 
384 	p9_debug(P9_DEBUG_MUX, "clnt %p req %p tag: %d\n", c, r, tag);
385 	spin_lock_irqsave(&c->lock, flags);
386 	idr_remove(&c->reqs, tag);
387 	spin_unlock_irqrestore(&c->lock, flags);
388 	return p9_req_put(r);
389 }
390 
391 static void p9_req_free(struct kref *ref)
392 {
393 	struct p9_req_t *r = container_of(ref, struct p9_req_t, refcount);
394 	p9_fcall_fini(&r->tc);
395 	p9_fcall_fini(&r->rc);
396 	kmem_cache_free(p9_req_cache, r);
397 }
398 
399 int p9_req_put(struct p9_req_t *r)
400 {
401 	return kref_put(&r->refcount, p9_req_free);
402 }
403 EXPORT_SYMBOL(p9_req_put);
404 
405 /**
406  * p9_tag_cleanup - cleans up tags structure and reclaims resources
407  * @c:  v9fs client struct
408  *
409  * This frees resources associated with the tags structure
410  *
411  */
412 static void p9_tag_cleanup(struct p9_client *c)
413 {
414 	struct p9_req_t *req;
415 	int id;
416 
417 	rcu_read_lock();
418 	idr_for_each_entry(&c->reqs, req, id) {
419 		pr_info("Tag %d still in use\n", id);
420 		if (p9_tag_remove(c, req) == 0)
421 			pr_warn("Packet with tag %d has still references",
422 				req->tc.tag);
423 	}
424 	rcu_read_unlock();
425 }
426 
427 /**
428  * p9_client_cb - call back from transport to client
429  * c: client state
430  * req: request received
431  *
432  */
433 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
434 {
435 	p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc.tag);
436 
437 	/*
438 	 * This barrier is needed to make sure any change made to req before
439 	 * the status change is visible to another thread
440 	 */
441 	smp_wmb();
442 	req->status = status;
443 
444 	wake_up(&req->wq);
445 	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
446 	p9_req_put(req);
447 }
448 EXPORT_SYMBOL(p9_client_cb);
449 
450 /**
451  * p9_parse_header - parse header arguments out of a packet
452  * @pdu: packet to parse
453  * @size: size of packet
454  * @type: type of request
455  * @tag: tag of packet
456  * @rewind: set if we need to rewind offset afterwards
457  */
458 
459 int
460 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type, int16_t *tag,
461 								int rewind)
462 {
463 	int8_t r_type;
464 	int16_t r_tag;
465 	int32_t r_size;
466 	int offset = pdu->offset;
467 	int err;
468 
469 	pdu->offset = 0;
470 
471 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
472 	if (err)
473 		goto rewind_and_exit;
474 
475 	if (type)
476 		*type = r_type;
477 	if (tag)
478 		*tag = r_tag;
479 	if (size)
480 		*size = r_size;
481 
482 	if (pdu->size != r_size || r_size < 7) {
483 		err = -EINVAL;
484 		goto rewind_and_exit;
485 	}
486 
487 	pdu->id = r_type;
488 	pdu->tag = r_tag;
489 
490 	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
491 		 pdu->size, pdu->id, pdu->tag);
492 
493 rewind_and_exit:
494 	if (rewind)
495 		pdu->offset = offset;
496 	return err;
497 }
498 EXPORT_SYMBOL(p9_parse_header);
499 
500 /**
501  * p9_check_errors - check 9p packet for error return and process it
502  * @c: current client instance
503  * @req: request to parse and check for error conditions
504  *
505  * returns error code if one is discovered, otherwise returns 0
506  *
507  * this will have to be more complicated if we have multiple
508  * error packet types
509  */
510 
511 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
512 {
513 	int8_t type;
514 	int err;
515 	int ecode;
516 
517 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
518 	if (req->rc.size >= c->msize) {
519 		p9_debug(P9_DEBUG_ERROR,
520 			 "requested packet size too big: %d\n",
521 			 req->rc.size);
522 		return -EIO;
523 	}
524 	/*
525 	 * dump the response from server
526 	 * This should be after check errors which poplulate pdu_fcall.
527 	 */
528 	trace_9p_protocol_dump(c, &req->rc);
529 	if (err) {
530 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
531 		return err;
532 	}
533 	if (type != P9_RERROR && type != P9_RLERROR)
534 		return 0;
535 
536 	if (!p9_is_proto_dotl(c)) {
537 		char *ename;
538 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
539 				  &ename, &ecode);
540 		if (err)
541 			goto out_err;
542 
543 		if (p9_is_proto_dotu(c) && ecode < 512)
544 			err = -ecode;
545 
546 		if (!err) {
547 			err = p9_errstr2errno(ename, strlen(ename));
548 
549 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
550 				 -ecode, ename);
551 		}
552 		kfree(ename);
553 	} else {
554 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
555 		err = -ecode;
556 
557 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
558 	}
559 
560 	return err;
561 
562 out_err:
563 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
564 
565 	return err;
566 }
567 
568 /**
569  * p9_check_zc_errors - check 9p packet for error return and process it
570  * @c: current client instance
571  * @req: request to parse and check for error conditions
572  * @in_hdrlen: Size of response protocol buffer.
573  *
574  * returns error code if one is discovered, otherwise returns 0
575  *
576  * this will have to be more complicated if we have multiple
577  * error packet types
578  */
579 
580 static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
581 			      struct iov_iter *uidata, int in_hdrlen)
582 {
583 	int err;
584 	int ecode;
585 	int8_t type;
586 	char *ename = NULL;
587 
588 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
589 	/*
590 	 * dump the response from server
591 	 * This should be after parse_header which poplulate pdu_fcall.
592 	 */
593 	trace_9p_protocol_dump(c, &req->rc);
594 	if (err) {
595 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
596 		return err;
597 	}
598 
599 	if (type != P9_RERROR && type != P9_RLERROR)
600 		return 0;
601 
602 	if (!p9_is_proto_dotl(c)) {
603 		/* Error is reported in string format */
604 		int len;
605 		/* 7 = header size for RERROR; */
606 		int inline_len = in_hdrlen - 7;
607 
608 		len = req->rc.size - req->rc.offset;
609 		if (len > (P9_ZC_HDR_SZ - 7)) {
610 			err = -EFAULT;
611 			goto out_err;
612 		}
613 
614 		ename = &req->rc.sdata[req->rc.offset];
615 		if (len > inline_len) {
616 			/* We have error in external buffer */
617 			if (!copy_from_iter_full(ename + inline_len,
618 					     len - inline_len, uidata)) {
619 				err = -EFAULT;
620 				goto out_err;
621 			}
622 		}
623 		ename = NULL;
624 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
625 				  &ename, &ecode);
626 		if (err)
627 			goto out_err;
628 
629 		if (p9_is_proto_dotu(c) && ecode < 512)
630 			err = -ecode;
631 
632 		if (!err) {
633 			err = p9_errstr2errno(ename, strlen(ename));
634 
635 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
636 				 -ecode, ename);
637 		}
638 		kfree(ename);
639 	} else {
640 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
641 		err = -ecode;
642 
643 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
644 	}
645 	return err;
646 
647 out_err:
648 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
649 	return err;
650 }
651 
652 static struct p9_req_t *
653 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
654 
655 /**
656  * p9_client_flush - flush (cancel) a request
657  * @c: client state
658  * @oldreq: request to cancel
659  *
660  * This sents a flush for a particular request and links
661  * the flush request to the original request.  The current
662  * code only supports a single flush request although the protocol
663  * allows for multiple flush requests to be sent for a single request.
664  *
665  */
666 
667 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
668 {
669 	struct p9_req_t *req;
670 	int16_t oldtag;
671 	int err;
672 
673 	err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
674 	if (err)
675 		return err;
676 
677 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
678 
679 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
680 	if (IS_ERR(req))
681 		return PTR_ERR(req);
682 
683 	/*
684 	 * if we haven't received a response for oldreq,
685 	 * remove it from the list
686 	 */
687 	if (oldreq->status == REQ_STATUS_SENT) {
688 		if (c->trans_mod->cancelled)
689 			c->trans_mod->cancelled(c, oldreq);
690 	}
691 
692 	p9_tag_remove(c, req);
693 	return 0;
694 }
695 
696 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
697 					      int8_t type, int req_size,
698 					      const char *fmt, va_list ap)
699 {
700 	int err;
701 	struct p9_req_t *req;
702 
703 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
704 
705 	/* we allow for any status other than disconnected */
706 	if (c->status == Disconnected)
707 		return ERR_PTR(-EIO);
708 
709 	/* if status is begin_disconnected we allow only clunk request */
710 	if ((c->status == BeginDisconnect) && (type != P9_TCLUNK))
711 		return ERR_PTR(-EIO);
712 
713 	req = p9_tag_alloc(c, type, req_size);
714 	if (IS_ERR(req))
715 		return req;
716 
717 	/* marshall the data */
718 	p9pdu_prepare(&req->tc, req->tc.tag, type);
719 	err = p9pdu_vwritef(&req->tc, c->proto_version, fmt, ap);
720 	if (err)
721 		goto reterr;
722 	p9pdu_finalize(c, &req->tc);
723 	trace_9p_client_req(c, type, req->tc.tag);
724 	return req;
725 reterr:
726 	p9_tag_remove(c, req);
727 	/* We have to put also the 2nd reference as it won't be used */
728 	p9_req_put(req);
729 	return ERR_PTR(err);
730 }
731 
732 /**
733  * p9_client_rpc - issue a request and wait for a response
734  * @c: client session
735  * @type: type of request
736  * @fmt: protocol format string (see protocol.c)
737  *
738  * Returns request structure (which client must free using p9_tag_remove)
739  */
740 
741 static struct p9_req_t *
742 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
743 {
744 	va_list ap;
745 	int sigpending, err;
746 	unsigned long flags;
747 	struct p9_req_t *req;
748 
749 	va_start(ap, fmt);
750 	req = p9_client_prepare_req(c, type, c->msize, fmt, ap);
751 	va_end(ap);
752 	if (IS_ERR(req))
753 		return req;
754 
755 	if (signal_pending(current)) {
756 		sigpending = 1;
757 		clear_thread_flag(TIF_SIGPENDING);
758 	} else
759 		sigpending = 0;
760 
761 	err = c->trans_mod->request(c, req);
762 	if (err < 0) {
763 		/* write won't happen */
764 		p9_req_put(req);
765 		if (err != -ERESTARTSYS && err != -EFAULT)
766 			c->status = Disconnected;
767 		goto recalc_sigpending;
768 	}
769 again:
770 	/* Wait for the response */
771 	err = wait_event_killable(req->wq, req->status >= REQ_STATUS_RCVD);
772 
773 	/*
774 	 * Make sure our req is coherent with regard to updates in other
775 	 * threads - echoes to wmb() in the callback
776 	 */
777 	smp_rmb();
778 
779 	if ((err == -ERESTARTSYS) && (c->status == Connected)
780 				  && (type == P9_TFLUSH)) {
781 		sigpending = 1;
782 		clear_thread_flag(TIF_SIGPENDING);
783 		goto again;
784 	}
785 
786 	if (req->status == REQ_STATUS_ERROR) {
787 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
788 		err = req->t_err;
789 	}
790 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
791 		p9_debug(P9_DEBUG_MUX, "flushing\n");
792 		sigpending = 1;
793 		clear_thread_flag(TIF_SIGPENDING);
794 
795 		if (c->trans_mod->cancel(c, req))
796 			p9_client_flush(c, req);
797 
798 		/* if we received the response anyway, don't signal error */
799 		if (req->status == REQ_STATUS_RCVD)
800 			err = 0;
801 	}
802 recalc_sigpending:
803 	if (sigpending) {
804 		spin_lock_irqsave(&current->sighand->siglock, flags);
805 		recalc_sigpending();
806 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
807 	}
808 	if (err < 0)
809 		goto reterr;
810 
811 	err = p9_check_errors(c, req);
812 	trace_9p_client_res(c, type, req->rc.tag, err);
813 	if (!err)
814 		return req;
815 reterr:
816 	p9_tag_remove(c, req);
817 	return ERR_PTR(safe_errno(err));
818 }
819 
820 /**
821  * p9_client_zc_rpc - issue a request and wait for a response
822  * @c: client session
823  * @type: type of request
824  * @uidata: destination for zero copy read
825  * @uodata: source for zero copy write
826  * @inlen: read buffer size
827  * @olen: write buffer size
828  * @hdrlen: reader header size, This is the size of response protocol data
829  * @fmt: protocol format string (see protocol.c)
830  *
831  * Returns request structure (which client must free using p9_tag_remove)
832  */
833 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
834 					 struct iov_iter *uidata,
835 					 struct iov_iter *uodata,
836 					 int inlen, int olen, int in_hdrlen,
837 					 const char *fmt, ...)
838 {
839 	va_list ap;
840 	int sigpending, err;
841 	unsigned long flags;
842 	struct p9_req_t *req;
843 
844 	va_start(ap, fmt);
845 	/*
846 	 * We allocate a inline protocol data of only 4k bytes.
847 	 * The actual content is passed in zero-copy fashion.
848 	 */
849 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, fmt, ap);
850 	va_end(ap);
851 	if (IS_ERR(req))
852 		return req;
853 
854 	if (signal_pending(current)) {
855 		sigpending = 1;
856 		clear_thread_flag(TIF_SIGPENDING);
857 	} else
858 		sigpending = 0;
859 
860 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
861 				       inlen, olen, in_hdrlen);
862 	if (err < 0) {
863 		if (err == -EIO)
864 			c->status = Disconnected;
865 		if (err != -ERESTARTSYS)
866 			goto recalc_sigpending;
867 	}
868 	if (req->status == REQ_STATUS_ERROR) {
869 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
870 		err = req->t_err;
871 	}
872 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
873 		p9_debug(P9_DEBUG_MUX, "flushing\n");
874 		sigpending = 1;
875 		clear_thread_flag(TIF_SIGPENDING);
876 
877 		if (c->trans_mod->cancel(c, req))
878 			p9_client_flush(c, req);
879 
880 		/* if we received the response anyway, don't signal error */
881 		if (req->status == REQ_STATUS_RCVD)
882 			err = 0;
883 	}
884 recalc_sigpending:
885 	if (sigpending) {
886 		spin_lock_irqsave(&current->sighand->siglock, flags);
887 		recalc_sigpending();
888 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
889 	}
890 	if (err < 0)
891 		goto reterr;
892 
893 	err = p9_check_zc_errors(c, req, uidata, in_hdrlen);
894 	trace_9p_client_res(c, type, req->rc.tag, err);
895 	if (!err)
896 		return req;
897 reterr:
898 	p9_tag_remove(c, req);
899 	return ERR_PTR(safe_errno(err));
900 }
901 
902 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
903 {
904 	int ret;
905 	struct p9_fid *fid;
906 
907 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
908 	fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
909 	if (!fid)
910 		return NULL;
911 
912 	memset(&fid->qid, 0, sizeof(struct p9_qid));
913 	fid->mode = -1;
914 	fid->uid = current_fsuid();
915 	fid->clnt = clnt;
916 	fid->rdir = NULL;
917 	fid->fid = 0;
918 
919 	idr_preload(GFP_KERNEL);
920 	spin_lock_irq(&clnt->lock);
921 	ret = idr_alloc_u32(&clnt->fids, fid, &fid->fid, P9_NOFID - 1,
922 			    GFP_NOWAIT);
923 	spin_unlock_irq(&clnt->lock);
924 	idr_preload_end();
925 
926 	if (!ret)
927 		return fid;
928 
929 	kfree(fid);
930 	return NULL;
931 }
932 
933 static void p9_fid_destroy(struct p9_fid *fid)
934 {
935 	struct p9_client *clnt;
936 	unsigned long flags;
937 
938 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
939 	clnt = fid->clnt;
940 	spin_lock_irqsave(&clnt->lock, flags);
941 	idr_remove(&clnt->fids, fid->fid);
942 	spin_unlock_irqrestore(&clnt->lock, flags);
943 	kfree(fid->rdir);
944 	kfree(fid);
945 }
946 
947 static int p9_client_version(struct p9_client *c)
948 {
949 	int err = 0;
950 	struct p9_req_t *req;
951 	char *version = NULL;
952 	int msize;
953 
954 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
955 		 c->msize, c->proto_version);
956 
957 	switch (c->proto_version) {
958 	case p9_proto_2000L:
959 		req = p9_client_rpc(c, P9_TVERSION, "ds",
960 					c->msize, "9P2000.L");
961 		break;
962 	case p9_proto_2000u:
963 		req = p9_client_rpc(c, P9_TVERSION, "ds",
964 					c->msize, "9P2000.u");
965 		break;
966 	case p9_proto_legacy:
967 		req = p9_client_rpc(c, P9_TVERSION, "ds",
968 					c->msize, "9P2000");
969 		break;
970 	default:
971 		return -EINVAL;
972 	}
973 
974 	if (IS_ERR(req))
975 		return PTR_ERR(req);
976 
977 	err = p9pdu_readf(&req->rc, c->proto_version, "ds", &msize, &version);
978 	if (err) {
979 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
980 		trace_9p_protocol_dump(c, &req->rc);
981 		goto error;
982 	}
983 
984 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
985 	if (!strncmp(version, "9P2000.L", 8))
986 		c->proto_version = p9_proto_2000L;
987 	else if (!strncmp(version, "9P2000.u", 8))
988 		c->proto_version = p9_proto_2000u;
989 	else if (!strncmp(version, "9P2000", 6))
990 		c->proto_version = p9_proto_legacy;
991 	else {
992 		p9_debug(P9_DEBUG_ERROR,
993 			 "server returned an unknown version: %s\n", version);
994 		err = -EREMOTEIO;
995 		goto error;
996 	}
997 
998 	if (msize < 4096) {
999 		p9_debug(P9_DEBUG_ERROR,
1000 			 "server returned a msize < 4096: %d\n", msize);
1001 		err = -EREMOTEIO;
1002 		goto error;
1003 	}
1004 	if (msize < c->msize)
1005 		c->msize = msize;
1006 
1007 error:
1008 	kfree(version);
1009 	p9_tag_remove(c, req);
1010 
1011 	return err;
1012 }
1013 
1014 struct p9_client *p9_client_create(const char *dev_name, char *options)
1015 {
1016 	int err;
1017 	struct p9_client *clnt;
1018 	char *client_id;
1019 
1020 	err = 0;
1021 	clnt = kmalloc(sizeof(struct p9_client), GFP_KERNEL);
1022 	if (!clnt)
1023 		return ERR_PTR(-ENOMEM);
1024 
1025 	clnt->trans_mod = NULL;
1026 	clnt->trans = NULL;
1027 	clnt->fcall_cache = NULL;
1028 
1029 	client_id = utsname()->nodename;
1030 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
1031 
1032 	spin_lock_init(&clnt->lock);
1033 	idr_init(&clnt->fids);
1034 	idr_init(&clnt->reqs);
1035 
1036 	err = parse_opts(options, clnt);
1037 	if (err < 0)
1038 		goto free_client;
1039 
1040 	if (!clnt->trans_mod)
1041 		clnt->trans_mod = v9fs_get_default_trans();
1042 
1043 	if (clnt->trans_mod == NULL) {
1044 		err = -EPROTONOSUPPORT;
1045 		p9_debug(P9_DEBUG_ERROR,
1046 			 "No transport defined or default transport\n");
1047 		goto free_client;
1048 	}
1049 
1050 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
1051 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
1052 
1053 	err = clnt->trans_mod->create(clnt, dev_name, options);
1054 	if (err)
1055 		goto put_trans;
1056 
1057 	if (clnt->msize > clnt->trans_mod->maxsize)
1058 		clnt->msize = clnt->trans_mod->maxsize;
1059 
1060 	if (clnt->msize < 4096) {
1061 		p9_debug(P9_DEBUG_ERROR,
1062 			 "Please specify a msize of at least 4k\n");
1063 		err = -EINVAL;
1064 		goto close_trans;
1065 	}
1066 
1067 	err = p9_client_version(clnt);
1068 	if (err)
1069 		goto close_trans;
1070 
1071 	/* P9_HDRSZ + 4 is the smallest packet header we can have that is
1072 	 * followed by data accessed from userspace by read
1073 	 */
1074 	clnt->fcall_cache =
1075 		kmem_cache_create_usercopy("9p-fcall-cache", clnt->msize,
1076 					   0, 0, P9_HDRSZ + 4,
1077 					   clnt->msize - (P9_HDRSZ + 4),
1078 					   NULL);
1079 
1080 	return clnt;
1081 
1082 close_trans:
1083 	clnt->trans_mod->close(clnt);
1084 put_trans:
1085 	v9fs_put_trans(clnt->trans_mod);
1086 free_client:
1087 	kfree(clnt);
1088 	return ERR_PTR(err);
1089 }
1090 EXPORT_SYMBOL(p9_client_create);
1091 
1092 void p9_client_destroy(struct p9_client *clnt)
1093 {
1094 	struct p9_fid *fid;
1095 	int id;
1096 
1097 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1098 
1099 	if (clnt->trans_mod)
1100 		clnt->trans_mod->close(clnt);
1101 
1102 	v9fs_put_trans(clnt->trans_mod);
1103 
1104 	idr_for_each_entry(&clnt->fids, fid, id) {
1105 		pr_info("Found fid %d not clunked\n", fid->fid);
1106 		p9_fid_destroy(fid);
1107 	}
1108 
1109 	p9_tag_cleanup(clnt);
1110 
1111 	kmem_cache_destroy(clnt->fcall_cache);
1112 	kfree(clnt);
1113 }
1114 EXPORT_SYMBOL(p9_client_destroy);
1115 
1116 void p9_client_disconnect(struct p9_client *clnt)
1117 {
1118 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1119 	clnt->status = Disconnected;
1120 }
1121 EXPORT_SYMBOL(p9_client_disconnect);
1122 
1123 void p9_client_begin_disconnect(struct p9_client *clnt)
1124 {
1125 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1126 	clnt->status = BeginDisconnect;
1127 }
1128 EXPORT_SYMBOL(p9_client_begin_disconnect);
1129 
1130 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1131 	const char *uname, kuid_t n_uname, const char *aname)
1132 {
1133 	int err = 0;
1134 	struct p9_req_t *req;
1135 	struct p9_fid *fid;
1136 	struct p9_qid qid;
1137 
1138 
1139 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1140 		 afid ? afid->fid : -1, uname, aname);
1141 	fid = p9_fid_create(clnt);
1142 	if (!fid) {
1143 		err = -ENOMEM;
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_tag_remove(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_tag_remove(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 (!fid) {
1193 			err = -ENOMEM;
1194 			goto error;
1195 		}
1196 
1197 		fid->uid = oldfid->uid;
1198 	} else
1199 		fid = oldfid;
1200 
1201 
1202 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1203 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1204 
1205 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1206 								nwname, wnames);
1207 	if (IS_ERR(req)) {
1208 		err = PTR_ERR(req);
1209 		goto error;
1210 	}
1211 
1212 	err = p9pdu_readf(&req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1213 	if (err) {
1214 		trace_9p_protocol_dump(clnt, &req->rc);
1215 		p9_tag_remove(clnt, req);
1216 		goto clunk_fid;
1217 	}
1218 	p9_tag_remove(clnt, req);
1219 
1220 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1221 
1222 	if (nwqids != nwname) {
1223 		err = -ENOENT;
1224 		goto clunk_fid;
1225 	}
1226 
1227 	for (count = 0; count < nwqids; count++)
1228 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1229 			count, wqids[count].type,
1230 			(unsigned long long)wqids[count].path,
1231 			wqids[count].version);
1232 
1233 	if (nwname)
1234 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1235 	else
1236 		fid->qid = oldfid->qid;
1237 
1238 	kfree(wqids);
1239 	return fid;
1240 
1241 clunk_fid:
1242 	kfree(wqids);
1243 	p9_client_clunk(fid);
1244 	fid = NULL;
1245 
1246 error:
1247 	if (fid && (fid != oldfid))
1248 		p9_fid_destroy(fid);
1249 
1250 	return ERR_PTR(err);
1251 }
1252 EXPORT_SYMBOL(p9_client_walk);
1253 
1254 int p9_client_open(struct p9_fid *fid, int mode)
1255 {
1256 	int err;
1257 	struct p9_client *clnt;
1258 	struct p9_req_t *req;
1259 	struct p9_qid qid;
1260 	int iounit;
1261 
1262 	clnt = fid->clnt;
1263 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1264 		p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1265 	err = 0;
1266 
1267 	if (fid->mode != -1)
1268 		return -EINVAL;
1269 
1270 	if (p9_is_proto_dotl(clnt))
1271 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode);
1272 	else
1273 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
1274 	if (IS_ERR(req)) {
1275 		err = PTR_ERR(req);
1276 		goto error;
1277 	}
1278 
1279 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1280 	if (err) {
1281 		trace_9p_protocol_dump(clnt, &req->rc);
1282 		goto free_and_error;
1283 	}
1284 
1285 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1286 		p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1287 		(unsigned long long)qid.path, qid.version, iounit);
1288 
1289 	fid->mode = mode;
1290 	fid->iounit = iounit;
1291 
1292 free_and_error:
1293 	p9_tag_remove(clnt, req);
1294 error:
1295 	return err;
1296 }
1297 EXPORT_SYMBOL(p9_client_open);
1298 
1299 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags, u32 mode,
1300 		kgid_t gid, struct p9_qid *qid)
1301 {
1302 	int err = 0;
1303 	struct p9_client *clnt;
1304 	struct p9_req_t *req;
1305 	int iounit;
1306 
1307 	p9_debug(P9_DEBUG_9P,
1308 			">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1309 			ofid->fid, name, flags, mode,
1310 		 	from_kgid(&init_user_ns, gid));
1311 	clnt = ofid->clnt;
1312 
1313 	if (ofid->mode != -1)
1314 		return -EINVAL;
1315 
1316 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1317 			mode, gid);
1318 	if (IS_ERR(req)) {
1319 		err = PTR_ERR(req);
1320 		goto error;
1321 	}
1322 
1323 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", qid, &iounit);
1324 	if (err) {
1325 		trace_9p_protocol_dump(clnt, &req->rc);
1326 		goto free_and_error;
1327 	}
1328 
1329 	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1330 			qid->type,
1331 			(unsigned long long)qid->path,
1332 			qid->version, iounit);
1333 
1334 	ofid->mode = mode;
1335 	ofid->iounit = iounit;
1336 
1337 free_and_error:
1338 	p9_tag_remove(clnt, req);
1339 error:
1340 	return err;
1341 }
1342 EXPORT_SYMBOL(p9_client_create_dotl);
1343 
1344 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1345 		     char *extension)
1346 {
1347 	int err;
1348 	struct p9_client *clnt;
1349 	struct p9_req_t *req;
1350 	struct p9_qid qid;
1351 	int iounit;
1352 
1353 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1354 						fid->fid, name, perm, mode);
1355 	err = 0;
1356 	clnt = fid->clnt;
1357 
1358 	if (fid->mode != -1)
1359 		return -EINVAL;
1360 
1361 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1362 				mode, extension);
1363 	if (IS_ERR(req)) {
1364 		err = PTR_ERR(req);
1365 		goto error;
1366 	}
1367 
1368 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1369 	if (err) {
1370 		trace_9p_protocol_dump(clnt, &req->rc);
1371 		goto free_and_error;
1372 	}
1373 
1374 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1375 				qid.type,
1376 				(unsigned long long)qid.path,
1377 				qid.version, iounit);
1378 
1379 	fid->mode = mode;
1380 	fid->iounit = iounit;
1381 
1382 free_and_error:
1383 	p9_tag_remove(clnt, req);
1384 error:
1385 	return err;
1386 }
1387 EXPORT_SYMBOL(p9_client_fcreate);
1388 
1389 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1390 		const char *symtgt, kgid_t gid, struct p9_qid *qid)
1391 {
1392 	int err = 0;
1393 	struct p9_client *clnt;
1394 	struct p9_req_t *req;
1395 
1396 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1397 			dfid->fid, name, symtgt);
1398 	clnt = dfid->clnt;
1399 
1400 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1401 			gid);
1402 	if (IS_ERR(req)) {
1403 		err = PTR_ERR(req);
1404 		goto error;
1405 	}
1406 
1407 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
1408 	if (err) {
1409 		trace_9p_protocol_dump(clnt, &req->rc);
1410 		goto free_and_error;
1411 	}
1412 
1413 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1414 			qid->type, (unsigned long long)qid->path, qid->version);
1415 
1416 free_and_error:
1417 	p9_tag_remove(clnt, req);
1418 error:
1419 	return err;
1420 }
1421 EXPORT_SYMBOL(p9_client_symlink);
1422 
1423 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1424 {
1425 	struct p9_client *clnt;
1426 	struct p9_req_t *req;
1427 
1428 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1429 			dfid->fid, oldfid->fid, newname);
1430 	clnt = dfid->clnt;
1431 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1432 			newname);
1433 	if (IS_ERR(req))
1434 		return PTR_ERR(req);
1435 
1436 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1437 	p9_tag_remove(clnt, req);
1438 	return 0;
1439 }
1440 EXPORT_SYMBOL(p9_client_link);
1441 
1442 int p9_client_fsync(struct p9_fid *fid, int datasync)
1443 {
1444 	int err;
1445 	struct p9_client *clnt;
1446 	struct p9_req_t *req;
1447 
1448 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1449 			fid->fid, datasync);
1450 	err = 0;
1451 	clnt = fid->clnt;
1452 
1453 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1454 	if (IS_ERR(req)) {
1455 		err = PTR_ERR(req);
1456 		goto error;
1457 	}
1458 
1459 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1460 
1461 	p9_tag_remove(clnt, req);
1462 
1463 error:
1464 	return err;
1465 }
1466 EXPORT_SYMBOL(p9_client_fsync);
1467 
1468 int p9_client_clunk(struct p9_fid *fid)
1469 {
1470 	int err;
1471 	struct p9_client *clnt;
1472 	struct p9_req_t *req;
1473 	int retries = 0;
1474 
1475 	if (!fid) {
1476 		pr_warn("%s (%d): Trying to clunk with NULL fid\n",
1477 			__func__, task_pid_nr(current));
1478 		dump_stack();
1479 		return 0;
1480 	}
1481 
1482 again:
1483 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n", fid->fid,
1484 								retries);
1485 	err = 0;
1486 	clnt = fid->clnt;
1487 
1488 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1489 	if (IS_ERR(req)) {
1490 		err = PTR_ERR(req);
1491 		goto error;
1492 	}
1493 
1494 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1495 
1496 	p9_tag_remove(clnt, req);
1497 error:
1498 	/*
1499 	 * Fid is not valid even after a failed clunk
1500 	 * If interrupted, retry once then give up and
1501 	 * leak fid until umount.
1502 	 */
1503 	if (err == -ERESTARTSYS) {
1504 		if (retries++ == 0)
1505 			goto again;
1506 	} else
1507 		p9_fid_destroy(fid);
1508 	return err;
1509 }
1510 EXPORT_SYMBOL(p9_client_clunk);
1511 
1512 int p9_client_remove(struct p9_fid *fid)
1513 {
1514 	int err;
1515 	struct p9_client *clnt;
1516 	struct p9_req_t *req;
1517 
1518 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1519 	err = 0;
1520 	clnt = fid->clnt;
1521 
1522 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1523 	if (IS_ERR(req)) {
1524 		err = PTR_ERR(req);
1525 		goto error;
1526 	}
1527 
1528 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1529 
1530 	p9_tag_remove(clnt, req);
1531 error:
1532 	if (err == -ERESTARTSYS)
1533 		p9_client_clunk(fid);
1534 	else
1535 		p9_fid_destroy(fid);
1536 	return err;
1537 }
1538 EXPORT_SYMBOL(p9_client_remove);
1539 
1540 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1541 {
1542 	int err = 0;
1543 	struct p9_req_t *req;
1544 	struct p9_client *clnt;
1545 
1546 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1547 		   dfid->fid, name, flags);
1548 
1549 	clnt = dfid->clnt;
1550 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1551 	if (IS_ERR(req)) {
1552 		err = PTR_ERR(req);
1553 		goto error;
1554 	}
1555 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1556 
1557 	p9_tag_remove(clnt, req);
1558 error:
1559 	return err;
1560 }
1561 EXPORT_SYMBOL(p9_client_unlinkat);
1562 
1563 int
1564 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1565 {
1566 	struct p9_client *clnt = fid->clnt;
1567 	struct p9_req_t *req;
1568 	int total = 0;
1569 	*err = 0;
1570 
1571 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n",
1572 		   fid->fid, (unsigned long long) offset, (int)iov_iter_count(to));
1573 
1574 	while (iov_iter_count(to)) {
1575 		int count = iov_iter_count(to);
1576 		int rsize, non_zc = 0;
1577 		char *dataptr;
1578 
1579 		rsize = fid->iounit;
1580 		if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1581 			rsize = clnt->msize - P9_IOHDRSZ;
1582 
1583 		if (count < rsize)
1584 			rsize = count;
1585 
1586 		/* Don't bother zerocopy for small IO (< 1024) */
1587 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1588 			/*
1589 			 * response header len is 11
1590 			 * PDU Header(7) + IO Size (4)
1591 			 */
1592 			req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1593 					       0, 11, "dqd", fid->fid,
1594 					       offset, rsize);
1595 		} else {
1596 			non_zc = 1;
1597 			req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1598 					    rsize);
1599 		}
1600 		if (IS_ERR(req)) {
1601 			*err = PTR_ERR(req);
1602 			break;
1603 		}
1604 
1605 		*err = p9pdu_readf(&req->rc, clnt->proto_version,
1606 				   "D", &count, &dataptr);
1607 		if (*err) {
1608 			trace_9p_protocol_dump(clnt, &req->rc);
1609 			p9_tag_remove(clnt, req);
1610 			break;
1611 		}
1612 		if (rsize < count) {
1613 			pr_err("bogus RREAD count (%d > %d)\n", count, rsize);
1614 			count = rsize;
1615 		}
1616 
1617 		p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1618 		if (!count) {
1619 			p9_tag_remove(clnt, req);
1620 			break;
1621 		}
1622 
1623 		if (non_zc) {
1624 			int n = copy_to_iter(dataptr, count, to);
1625 			total += n;
1626 			offset += n;
1627 			if (n != count) {
1628 				*err = -EFAULT;
1629 				p9_tag_remove(clnt, req);
1630 				break;
1631 			}
1632 		} else {
1633 			iov_iter_advance(to, count);
1634 			total += count;
1635 			offset += count;
1636 		}
1637 		p9_tag_remove(clnt, req);
1638 	}
1639 	return total;
1640 }
1641 EXPORT_SYMBOL(p9_client_read);
1642 
1643 int
1644 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1645 {
1646 	struct p9_client *clnt = fid->clnt;
1647 	struct p9_req_t *req;
1648 	int total = 0;
1649 	*err = 0;
1650 
1651 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n",
1652 				fid->fid, (unsigned long long) offset,
1653 				iov_iter_count(from));
1654 
1655 	while (iov_iter_count(from)) {
1656 		int count = iov_iter_count(from);
1657 		int rsize = fid->iounit;
1658 		if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1659 			rsize = clnt->msize - P9_IOHDRSZ;
1660 
1661 		if (count < rsize)
1662 			rsize = count;
1663 
1664 		/* Don't bother zerocopy for small IO (< 1024) */
1665 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1666 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1667 					       rsize, P9_ZC_HDR_SZ, "dqd",
1668 					       fid->fid, offset, rsize);
1669 		} else {
1670 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1671 						    offset, rsize, from);
1672 		}
1673 		if (IS_ERR(req)) {
1674 			*err = PTR_ERR(req);
1675 			break;
1676 		}
1677 
1678 		*err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &count);
1679 		if (*err) {
1680 			trace_9p_protocol_dump(clnt, &req->rc);
1681 			p9_tag_remove(clnt, req);
1682 			break;
1683 		}
1684 		if (rsize < count) {
1685 			pr_err("bogus RWRITE count (%d > %d)\n", count, rsize);
1686 			count = rsize;
1687 		}
1688 
1689 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1690 
1691 		p9_tag_remove(clnt, req);
1692 		iov_iter_advance(from, count);
1693 		total += count;
1694 		offset += count;
1695 	}
1696 	return total;
1697 }
1698 EXPORT_SYMBOL(p9_client_write);
1699 
1700 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1701 {
1702 	int err;
1703 	struct p9_client *clnt;
1704 	struct p9_wstat *ret = kmalloc(sizeof(struct p9_wstat), GFP_KERNEL);
1705 	struct p9_req_t *req;
1706 	u16 ignored;
1707 
1708 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1709 
1710 	if (!ret)
1711 		return ERR_PTR(-ENOMEM);
1712 
1713 	err = 0;
1714 	clnt = fid->clnt;
1715 
1716 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1717 	if (IS_ERR(req)) {
1718 		err = PTR_ERR(req);
1719 		goto error;
1720 	}
1721 
1722 	err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
1723 	if (err) {
1724 		trace_9p_protocol_dump(clnt, &req->rc);
1725 		p9_tag_remove(clnt, req);
1726 		goto error;
1727 	}
1728 
1729 	p9_debug(P9_DEBUG_9P,
1730 		"<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1731 		"<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1732 		"<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1733 		"<<<    uid=%d gid=%d n_muid=%d\n",
1734 		ret->size, ret->type, ret->dev, ret->qid.type,
1735 		(unsigned long long)ret->qid.path, ret->qid.version, ret->mode,
1736 		ret->atime, ret->mtime, (unsigned long long)ret->length,
1737 		ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1738 		from_kuid(&init_user_ns, ret->n_uid),
1739 		from_kgid(&init_user_ns, ret->n_gid),
1740 		from_kuid(&init_user_ns, ret->n_muid));
1741 
1742 	p9_tag_remove(clnt, req);
1743 	return ret;
1744 
1745 error:
1746 	kfree(ret);
1747 	return ERR_PTR(err);
1748 }
1749 EXPORT_SYMBOL(p9_client_stat);
1750 
1751 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1752 							u64 request_mask)
1753 {
1754 	int err;
1755 	struct p9_client *clnt;
1756 	struct p9_stat_dotl *ret = kmalloc(sizeof(struct p9_stat_dotl),
1757 								GFP_KERNEL);
1758 	struct p9_req_t *req;
1759 
1760 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1761 							fid->fid, request_mask);
1762 
1763 	if (!ret)
1764 		return ERR_PTR(-ENOMEM);
1765 
1766 	err = 0;
1767 	clnt = fid->clnt;
1768 
1769 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1770 	if (IS_ERR(req)) {
1771 		err = PTR_ERR(req);
1772 		goto error;
1773 	}
1774 
1775 	err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
1776 	if (err) {
1777 		trace_9p_protocol_dump(clnt, &req->rc);
1778 		p9_tag_remove(clnt, req);
1779 		goto error;
1780 	}
1781 
1782 	p9_debug(P9_DEBUG_9P,
1783 		"<<< RGETATTR st_result_mask=%lld\n"
1784 		"<<< qid=%x.%llx.%x\n"
1785 		"<<< st_mode=%8.8x st_nlink=%llu\n"
1786 		"<<< st_uid=%d st_gid=%d\n"
1787 		"<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1788 		"<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1789 		"<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1790 		"<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1791 		"<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1792 		"<<< st_gen=%lld st_data_version=%lld\n",
1793 		ret->st_result_mask, ret->qid.type, ret->qid.path,
1794 		ret->qid.version, ret->st_mode, ret->st_nlink,
1795 		from_kuid(&init_user_ns, ret->st_uid),
1796 		from_kgid(&init_user_ns, ret->st_gid),
1797 		ret->st_rdev, ret->st_size, ret->st_blksize,
1798 		ret->st_blocks, ret->st_atime_sec, ret->st_atime_nsec,
1799 		ret->st_mtime_sec, ret->st_mtime_nsec, ret->st_ctime_sec,
1800 		ret->st_ctime_nsec, ret->st_btime_sec, ret->st_btime_nsec,
1801 		ret->st_gen, ret->st_data_version);
1802 
1803 	p9_tag_remove(clnt, req);
1804 	return ret;
1805 
1806 error:
1807 	kfree(ret);
1808 	return ERR_PTR(err);
1809 }
1810 EXPORT_SYMBOL(p9_client_getattr_dotl);
1811 
1812 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1813 {
1814 	int ret;
1815 
1816 	/* NOTE: size shouldn't include its own length */
1817 	/* size[2] type[2] dev[4] qid[13] */
1818 	/* mode[4] atime[4] mtime[4] length[8]*/
1819 	/* name[s] uid[s] gid[s] muid[s] */
1820 	ret = 2+4+13+4+4+4+8+2+2+2+2;
1821 
1822 	if (wst->name)
1823 		ret += strlen(wst->name);
1824 	if (wst->uid)
1825 		ret += strlen(wst->uid);
1826 	if (wst->gid)
1827 		ret += strlen(wst->gid);
1828 	if (wst->muid)
1829 		ret += strlen(wst->muid);
1830 
1831 	if ((proto_version == p9_proto_2000u) ||
1832 		(proto_version == p9_proto_2000L)) {
1833 		ret += 2+4+4+4;	/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1834 		if (wst->extension)
1835 			ret += strlen(wst->extension);
1836 	}
1837 
1838 	return ret;
1839 }
1840 
1841 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1842 {
1843 	int err;
1844 	struct p9_req_t *req;
1845 	struct p9_client *clnt;
1846 
1847 	err = 0;
1848 	clnt = fid->clnt;
1849 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1850 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n", fid->fid);
1851 	p9_debug(P9_DEBUG_9P,
1852 		"     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1853 		"     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1854 		"     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1855 		"     uid=%d gid=%d n_muid=%d\n",
1856 		wst->size, wst->type, wst->dev, wst->qid.type,
1857 		(unsigned long long)wst->qid.path, wst->qid.version, wst->mode,
1858 		wst->atime, wst->mtime, (unsigned long long)wst->length,
1859 		wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1860 		from_kuid(&init_user_ns, wst->n_uid),
1861 		from_kgid(&init_user_ns, wst->n_gid),
1862 		from_kuid(&init_user_ns, wst->n_muid));
1863 
1864 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS", fid->fid, wst->size+2, wst);
1865 	if (IS_ERR(req)) {
1866 		err = PTR_ERR(req);
1867 		goto error;
1868 	}
1869 
1870 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1871 
1872 	p9_tag_remove(clnt, req);
1873 error:
1874 	return err;
1875 }
1876 EXPORT_SYMBOL(p9_client_wstat);
1877 
1878 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1879 {
1880 	int err;
1881 	struct p9_req_t *req;
1882 	struct p9_client *clnt;
1883 
1884 	err = 0;
1885 	clnt = fid->clnt;
1886 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1887 	p9_debug(P9_DEBUG_9P,
1888 		"    valid=%x mode=%x uid=%d gid=%d size=%lld\n"
1889 		"    atime_sec=%lld atime_nsec=%lld\n"
1890 		"    mtime_sec=%lld mtime_nsec=%lld\n",
1891 		p9attr->valid, p9attr->mode,
1892 		from_kuid(&init_user_ns, p9attr->uid),
1893 		from_kgid(&init_user_ns, p9attr->gid),
1894 		p9attr->size, p9attr->atime_sec, p9attr->atime_nsec,
1895 		p9attr->mtime_sec, p9attr->mtime_nsec);
1896 
1897 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1898 
1899 	if (IS_ERR(req)) {
1900 		err = PTR_ERR(req);
1901 		goto error;
1902 	}
1903 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1904 	p9_tag_remove(clnt, req);
1905 error:
1906 	return err;
1907 }
1908 EXPORT_SYMBOL(p9_client_setattr);
1909 
1910 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1911 {
1912 	int err;
1913 	struct p9_req_t *req;
1914 	struct p9_client *clnt;
1915 
1916 	err = 0;
1917 	clnt = fid->clnt;
1918 
1919 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1920 
1921 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1922 	if (IS_ERR(req)) {
1923 		err = PTR_ERR(req);
1924 		goto error;
1925 	}
1926 
1927 	err = p9pdu_readf(&req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1928 			  &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1929 			  &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1930 	if (err) {
1931 		trace_9p_protocol_dump(clnt, &req->rc);
1932 		p9_tag_remove(clnt, req);
1933 		goto error;
1934 	}
1935 
1936 	p9_debug(P9_DEBUG_9P, "<<< RSTATFS fid %d type 0x%lx bsize %ld "
1937 		"blocks %llu bfree %llu bavail %llu files %llu ffree %llu "
1938 		"fsid %llu namelen %ld\n",
1939 		fid->fid, (long unsigned int)sb->type, (long int)sb->bsize,
1940 		sb->blocks, sb->bfree, sb->bavail, sb->files,  sb->ffree,
1941 		sb->fsid, (long int)sb->namelen);
1942 
1943 	p9_tag_remove(clnt, req);
1944 error:
1945 	return err;
1946 }
1947 EXPORT_SYMBOL(p9_client_statfs);
1948 
1949 int p9_client_rename(struct p9_fid *fid,
1950 		     struct p9_fid *newdirfid, const char *name)
1951 {
1952 	int err;
1953 	struct p9_req_t *req;
1954 	struct p9_client *clnt;
1955 
1956 	err = 0;
1957 	clnt = fid->clnt;
1958 
1959 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1960 			fid->fid, newdirfid->fid, name);
1961 
1962 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1963 			newdirfid->fid, name);
1964 	if (IS_ERR(req)) {
1965 		err = PTR_ERR(req);
1966 		goto error;
1967 	}
1968 
1969 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1970 
1971 	p9_tag_remove(clnt, req);
1972 error:
1973 	return err;
1974 }
1975 EXPORT_SYMBOL(p9_client_rename);
1976 
1977 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
1978 		       struct p9_fid *newdirfid, const char *new_name)
1979 {
1980 	int err;
1981 	struct p9_req_t *req;
1982 	struct p9_client *clnt;
1983 
1984 	err = 0;
1985 	clnt = olddirfid->clnt;
1986 
1987 	p9_debug(P9_DEBUG_9P, ">>> TRENAMEAT olddirfid %d old name %s"
1988 		   " newdirfid %d new name %s\n", olddirfid->fid, old_name,
1989 		   newdirfid->fid, new_name);
1990 
1991 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
1992 			    old_name, newdirfid->fid, new_name);
1993 	if (IS_ERR(req)) {
1994 		err = PTR_ERR(req);
1995 		goto error;
1996 	}
1997 
1998 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
1999 		   newdirfid->fid, new_name);
2000 
2001 	p9_tag_remove(clnt, req);
2002 error:
2003 	return err;
2004 }
2005 EXPORT_SYMBOL(p9_client_renameat);
2006 
2007 /*
2008  * An xattrwalk without @attr_name gives the fid for the lisxattr namespace
2009  */
2010 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
2011 				const char *attr_name, u64 *attr_size)
2012 {
2013 	int err;
2014 	struct p9_req_t *req;
2015 	struct p9_client *clnt;
2016 	struct p9_fid *attr_fid;
2017 
2018 	err = 0;
2019 	clnt = file_fid->clnt;
2020 	attr_fid = p9_fid_create(clnt);
2021 	if (!attr_fid) {
2022 		err = -ENOMEM;
2023 		goto error;
2024 	}
2025 	p9_debug(P9_DEBUG_9P,
2026 		">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
2027 		file_fid->fid, attr_fid->fid, attr_name);
2028 
2029 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
2030 			file_fid->fid, attr_fid->fid, attr_name);
2031 	if (IS_ERR(req)) {
2032 		err = PTR_ERR(req);
2033 		goto error;
2034 	}
2035 	err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
2036 	if (err) {
2037 		trace_9p_protocol_dump(clnt, &req->rc);
2038 		p9_tag_remove(clnt, req);
2039 		goto clunk_fid;
2040 	}
2041 	p9_tag_remove(clnt, req);
2042 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
2043 		attr_fid->fid, *attr_size);
2044 	return attr_fid;
2045 clunk_fid:
2046 	p9_client_clunk(attr_fid);
2047 	attr_fid = NULL;
2048 error:
2049 	if (attr_fid && (attr_fid != file_fid))
2050 		p9_fid_destroy(attr_fid);
2051 
2052 	return ERR_PTR(err);
2053 }
2054 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
2055 
2056 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
2057 			u64 attr_size, int flags)
2058 {
2059 	int err;
2060 	struct p9_req_t *req;
2061 	struct p9_client *clnt;
2062 
2063 	p9_debug(P9_DEBUG_9P,
2064 		">>> TXATTRCREATE fid %d name  %s size %lld flag %d\n",
2065 		fid->fid, name, (long long)attr_size, flags);
2066 	err = 0;
2067 	clnt = fid->clnt;
2068 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
2069 			fid->fid, name, attr_size, flags);
2070 	if (IS_ERR(req)) {
2071 		err = PTR_ERR(req);
2072 		goto error;
2073 	}
2074 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
2075 	p9_tag_remove(clnt, req);
2076 error:
2077 	return err;
2078 }
2079 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
2080 
2081 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
2082 {
2083 	int err, rsize, non_zc = 0;
2084 	struct p9_client *clnt;
2085 	struct p9_req_t *req;
2086 	char *dataptr;
2087 	struct kvec kv = {.iov_base = data, .iov_len = count};
2088 	struct iov_iter to;
2089 
2090 	iov_iter_kvec(&to, READ, &kv, 1, count);
2091 
2092 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
2093 				fid->fid, (unsigned long long) offset, count);
2094 
2095 	err = 0;
2096 	clnt = fid->clnt;
2097 
2098 	rsize = fid->iounit;
2099 	if (!rsize || rsize > clnt->msize-P9_READDIRHDRSZ)
2100 		rsize = clnt->msize - P9_READDIRHDRSZ;
2101 
2102 	if (count < rsize)
2103 		rsize = count;
2104 
2105 	/* Don't bother zerocopy for small IO (< 1024) */
2106 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2107 		/*
2108 		 * response header len is 11
2109 		 * PDU Header(7) + IO Size (4)
2110 		 */
2111 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2112 				       11, "dqd", fid->fid, offset, rsize);
2113 	} else {
2114 		non_zc = 1;
2115 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2116 				    offset, rsize);
2117 	}
2118 	if (IS_ERR(req)) {
2119 		err = PTR_ERR(req);
2120 		goto error;
2121 	}
2122 
2123 	err = p9pdu_readf(&req->rc, clnt->proto_version, "D", &count, &dataptr);
2124 	if (err) {
2125 		trace_9p_protocol_dump(clnt, &req->rc);
2126 		goto free_and_error;
2127 	}
2128 	if (rsize < count) {
2129 		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
2130 		count = rsize;
2131 	}
2132 
2133 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
2134 
2135 	if (non_zc)
2136 		memmove(data, dataptr, count);
2137 
2138 	p9_tag_remove(clnt, req);
2139 	return count;
2140 
2141 free_and_error:
2142 	p9_tag_remove(clnt, req);
2143 error:
2144 	return err;
2145 }
2146 EXPORT_SYMBOL(p9_client_readdir);
2147 
2148 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2149 			dev_t rdev, kgid_t gid, struct p9_qid *qid)
2150 {
2151 	int err;
2152 	struct p9_client *clnt;
2153 	struct p9_req_t *req;
2154 
2155 	err = 0;
2156 	clnt = fid->clnt;
2157 	p9_debug(P9_DEBUG_9P, ">>> TMKNOD fid %d name %s mode %d major %d "
2158 		"minor %d\n", fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2159 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2160 		MAJOR(rdev), MINOR(rdev), gid);
2161 	if (IS_ERR(req))
2162 		return PTR_ERR(req);
2163 
2164 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2165 	if (err) {
2166 		trace_9p_protocol_dump(clnt, &req->rc);
2167 		goto error;
2168 	}
2169 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n", qid->type,
2170 				(unsigned long long)qid->path, qid->version);
2171 
2172 error:
2173 	p9_tag_remove(clnt, req);
2174 	return err;
2175 
2176 }
2177 EXPORT_SYMBOL(p9_client_mknod_dotl);
2178 
2179 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2180 				kgid_t gid, struct p9_qid *qid)
2181 {
2182 	int err;
2183 	struct p9_client *clnt;
2184 	struct p9_req_t *req;
2185 
2186 	err = 0;
2187 	clnt = fid->clnt;
2188 	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
2189 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
2190 	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg", fid->fid, name, mode,
2191 		gid);
2192 	if (IS_ERR(req))
2193 		return PTR_ERR(req);
2194 
2195 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2196 	if (err) {
2197 		trace_9p_protocol_dump(clnt, &req->rc);
2198 		goto error;
2199 	}
2200 	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
2201 				(unsigned long long)qid->path, qid->version);
2202 
2203 error:
2204 	p9_tag_remove(clnt, req);
2205 	return err;
2206 
2207 }
2208 EXPORT_SYMBOL(p9_client_mkdir_dotl);
2209 
2210 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
2211 {
2212 	int err;
2213 	struct p9_client *clnt;
2214 	struct p9_req_t *req;
2215 
2216 	err = 0;
2217 	clnt = fid->clnt;
2218 	p9_debug(P9_DEBUG_9P, ">>> TLOCK fid %d type %i flags %d "
2219 			"start %lld length %lld proc_id %d client_id %s\n",
2220 			fid->fid, flock->type, flock->flags, flock->start,
2221 			flock->length, flock->proc_id, flock->client_id);
2222 
2223 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2224 				flock->flags, flock->start, flock->length,
2225 					flock->proc_id, flock->client_id);
2226 
2227 	if (IS_ERR(req))
2228 		return PTR_ERR(req);
2229 
2230 	err = p9pdu_readf(&req->rc, clnt->proto_version, "b", status);
2231 	if (err) {
2232 		trace_9p_protocol_dump(clnt, &req->rc);
2233 		goto error;
2234 	}
2235 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2236 error:
2237 	p9_tag_remove(clnt, req);
2238 	return err;
2239 
2240 }
2241 EXPORT_SYMBOL(p9_client_lock_dotl);
2242 
2243 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2244 {
2245 	int err;
2246 	struct p9_client *clnt;
2247 	struct p9_req_t *req;
2248 
2249 	err = 0;
2250 	clnt = fid->clnt;
2251 	p9_debug(P9_DEBUG_9P, ">>> TGETLOCK fid %d, type %i start %lld "
2252 		"length %lld proc_id %d client_id %s\n", fid->fid, glock->type,
2253 		glock->start, glock->length, glock->proc_id, glock->client_id);
2254 
2255 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,  glock->type,
2256 		glock->start, glock->length, glock->proc_id, glock->client_id);
2257 
2258 	if (IS_ERR(req))
2259 		return PTR_ERR(req);
2260 
2261 	err = p9pdu_readf(&req->rc, clnt->proto_version, "bqqds", &glock->type,
2262 			  &glock->start, &glock->length, &glock->proc_id,
2263 			  &glock->client_id);
2264 	if (err) {
2265 		trace_9p_protocol_dump(clnt, &req->rc);
2266 		goto error;
2267 	}
2268 	p9_debug(P9_DEBUG_9P, "<<< RGETLOCK type %i start %lld length %lld "
2269 		"proc_id %d client_id %s\n", glock->type, glock->start,
2270 		glock->length, glock->proc_id, glock->client_id);
2271 error:
2272 	p9_tag_remove(clnt, req);
2273 	return err;
2274 }
2275 EXPORT_SYMBOL(p9_client_getlock_dotl);
2276 
2277 int p9_client_readlink(struct p9_fid *fid, char **target)
2278 {
2279 	int err;
2280 	struct p9_client *clnt;
2281 	struct p9_req_t *req;
2282 
2283 	err = 0;
2284 	clnt = fid->clnt;
2285 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2286 
2287 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2288 	if (IS_ERR(req))
2289 		return PTR_ERR(req);
2290 
2291 	err = p9pdu_readf(&req->rc, clnt->proto_version, "s", target);
2292 	if (err) {
2293 		trace_9p_protocol_dump(clnt, &req->rc);
2294 		goto error;
2295 	}
2296 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2297 error:
2298 	p9_tag_remove(clnt, req);
2299 	return err;
2300 }
2301 EXPORT_SYMBOL(p9_client_readlink);
2302 
2303 int __init p9_client_init(void)
2304 {
2305 	p9_req_cache = KMEM_CACHE(p9_req_t, SLAB_TYPESAFE_BY_RCU);
2306 	return p9_req_cache ? 0 : -ENOMEM;
2307 }
2308 
2309 void __exit p9_client_exit(void)
2310 {
2311 	kmem_cache_destroy(p9_req_cache);
2312 }
2313