xref: /linux/net/9p/client.c (revision 0c8a32eed1625a65798286fb73fea8710a908545)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * net/9p/clnt.c
4  *
5  * 9P Client
6  *
7  *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
8  *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
9  */
10 
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12 
13 #include <linux/module.h>
14 #include <linux/errno.h>
15 #include <linux/fs.h>
16 #include <linux/poll.h>
17 #include <linux/idr.h>
18 #include <linux/mutex.h>
19 #include <linux/slab.h>
20 #include <linux/sched/signal.h>
21 #include <linux/uaccess.h>
22 #include <linux/uio.h>
23 #include <net/9p/9p.h>
24 #include <linux/parser.h>
25 #include <linux/seq_file.h>
26 #include <net/9p/client.h>
27 #include <net/9p/transport.h>
28 #include "protocol.h"
29 
30 #define CREATE_TRACE_POINTS
31 #include <trace/events/9p.h>
32 
33 /*
34   * Client Option Parsing (code inspired by NFS code)
35   *  - a little lazy - parse all client options
36   */
37 
38 enum {
39 	Opt_msize,
40 	Opt_trans,
41 	Opt_legacy,
42 	Opt_version,
43 	Opt_err,
44 };
45 
46 static const match_table_t tokens = {
47 	{Opt_msize, "msize=%u"},
48 	{Opt_legacy, "noextend"},
49 	{Opt_trans, "trans=%s"},
50 	{Opt_version, "version=%s"},
51 	{Opt_err, NULL},
52 };
53 
54 inline int p9_is_proto_dotl(struct p9_client *clnt)
55 {
56 	return clnt->proto_version == p9_proto_2000L;
57 }
58 EXPORT_SYMBOL(p9_is_proto_dotl);
59 
60 inline int p9_is_proto_dotu(struct p9_client *clnt)
61 {
62 	return clnt->proto_version == p9_proto_2000u;
63 }
64 EXPORT_SYMBOL(p9_is_proto_dotu);
65 
66 int p9_show_client_options(struct seq_file *m, struct p9_client *clnt)
67 {
68 	if (clnt->msize != 8192)
69 		seq_printf(m, ",msize=%u", clnt->msize);
70 	seq_printf(m, ",trans=%s", clnt->trans_mod->name);
71 
72 	switch (clnt->proto_version) {
73 	case p9_proto_legacy:
74 		seq_puts(m, ",noextend");
75 		break;
76 	case p9_proto_2000u:
77 		seq_puts(m, ",version=9p2000.u");
78 		break;
79 	case p9_proto_2000L:
80 		/* Default */
81 		break;
82 	}
83 
84 	if (clnt->trans_mod->show_options)
85 		return clnt->trans_mod->show_options(m, clnt);
86 	return 0;
87 }
88 EXPORT_SYMBOL(p9_show_client_options);
89 
90 /*
91  * Some error codes are taken directly from the server replies,
92  * make sure they are valid.
93  */
94 static int safe_errno(int err)
95 {
96 	if ((err > 0) || (err < -MAX_ERRNO)) {
97 		p9_debug(P9_DEBUG_ERROR, "Invalid error code %d\n", err);
98 		return -EPROTO;
99 	}
100 	return err;
101 }
102 
103 
104 /* Interpret mount option for protocol version */
105 static int get_protocol_version(char *s)
106 {
107 	int version = -EINVAL;
108 
109 	if (!strcmp(s, "9p2000")) {
110 		version = p9_proto_legacy;
111 		p9_debug(P9_DEBUG_9P, "Protocol version: Legacy\n");
112 	} else if (!strcmp(s, "9p2000.u")) {
113 		version = p9_proto_2000u;
114 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.u\n");
115 	} else if (!strcmp(s, "9p2000.L")) {
116 		version = p9_proto_2000L;
117 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.L\n");
118 	} else
119 		pr_info("Unknown protocol version %s\n", s);
120 
121 	return version;
122 }
123 
124 /**
125  * parse_options - parse mount options into client structure
126  * @opts: options string passed from mount
127  * @clnt: existing v9fs client information
128  *
129  * Return 0 upon success, -ERRNO upon failure
130  */
131 
132 static int parse_opts(char *opts, struct p9_client *clnt)
133 {
134 	char *options, *tmp_options;
135 	char *p;
136 	substring_t args[MAX_OPT_ARGS];
137 	int option;
138 	char *s;
139 	int ret = 0;
140 
141 	clnt->proto_version = p9_proto_2000L;
142 	clnt->msize = 8192;
143 
144 	if (!opts)
145 		return 0;
146 
147 	tmp_options = kstrdup(opts, GFP_KERNEL);
148 	if (!tmp_options) {
149 		p9_debug(P9_DEBUG_ERROR,
150 			 "failed to allocate copy of option string\n");
151 		return -ENOMEM;
152 	}
153 	options = tmp_options;
154 
155 	while ((p = strsep(&options, ",")) != NULL) {
156 		int token, r;
157 		if (!*p)
158 			continue;
159 		token = match_token(p, tokens, args);
160 		switch (token) {
161 		case Opt_msize:
162 			r = match_int(&args[0], &option);
163 			if (r < 0) {
164 				p9_debug(P9_DEBUG_ERROR,
165 					 "integer field, but no integer?\n");
166 				ret = r;
167 				continue;
168 			}
169 			if (option < 4096) {
170 				p9_debug(P9_DEBUG_ERROR,
171 					 "msize should be at least 4k\n");
172 				ret = -EINVAL;
173 				continue;
174 			}
175 			clnt->msize = option;
176 			break;
177 		case Opt_trans:
178 			s = match_strdup(&args[0]);
179 			if (!s) {
180 				ret = -ENOMEM;
181 				p9_debug(P9_DEBUG_ERROR,
182 					 "problem allocating copy of trans arg\n");
183 				goto free_and_return;
184 			}
185 
186 			v9fs_put_trans(clnt->trans_mod);
187 			clnt->trans_mod = v9fs_get_trans_by_name(s);
188 			if (clnt->trans_mod == NULL) {
189 				pr_info("Could not find request transport: %s\n",
190 					s);
191 				ret = -EINVAL;
192 			}
193 			kfree(s);
194 			break;
195 		case Opt_legacy:
196 			clnt->proto_version = p9_proto_legacy;
197 			break;
198 		case Opt_version:
199 			s = match_strdup(&args[0]);
200 			if (!s) {
201 				ret = -ENOMEM;
202 				p9_debug(P9_DEBUG_ERROR,
203 					 "problem allocating copy of version arg\n");
204 				goto free_and_return;
205 			}
206 			r = get_protocol_version(s);
207 			if (r < 0)
208 				ret = r;
209 			else
210 				clnt->proto_version = r;
211 			kfree(s);
212 			break;
213 		default:
214 			continue;
215 		}
216 	}
217 
218 free_and_return:
219 	if (ret)
220 		v9fs_put_trans(clnt->trans_mod);
221 	kfree(tmp_options);
222 	return ret;
223 }
224 
225 static int p9_fcall_init(struct p9_client *c, struct p9_fcall *fc,
226 			 int alloc_msize)
227 {
228 	if (likely(c->fcall_cache) && alloc_msize == c->msize) {
229 		fc->sdata = kmem_cache_alloc(c->fcall_cache, GFP_NOFS);
230 		fc->cache = c->fcall_cache;
231 	} else {
232 		fc->sdata = kmalloc(alloc_msize, GFP_NOFS);
233 		fc->cache = NULL;
234 	}
235 	if (!fc->sdata)
236 		return -ENOMEM;
237 	fc->capacity = alloc_msize;
238 	return 0;
239 }
240 
241 void p9_fcall_fini(struct p9_fcall *fc)
242 {
243 	/* sdata can be NULL for interrupted requests in trans_rdma,
244 	 * and kmem_cache_free does not do NULL-check for us
245 	 */
246 	if (unlikely(!fc->sdata))
247 		return;
248 
249 	if (fc->cache)
250 		kmem_cache_free(fc->cache, fc->sdata);
251 	else
252 		kfree(fc->sdata);
253 }
254 EXPORT_SYMBOL(p9_fcall_fini);
255 
256 static struct kmem_cache *p9_req_cache;
257 
258 /**
259  * p9_req_alloc - Allocate a new request.
260  * @c: Client session.
261  * @type: Transaction type.
262  * @max_size: Maximum packet size for this request.
263  *
264  * Context: Process context.
265  * Return: Pointer to new request.
266  */
267 static struct p9_req_t *
268 p9_tag_alloc(struct p9_client *c, int8_t type, unsigned int max_size)
269 {
270 	struct p9_req_t *req = kmem_cache_alloc(p9_req_cache, GFP_NOFS);
271 	int alloc_msize = min(c->msize, max_size);
272 	int tag;
273 
274 	if (!req)
275 		return ERR_PTR(-ENOMEM);
276 
277 	if (p9_fcall_init(c, &req->tc, alloc_msize))
278 		goto free_req;
279 	if (p9_fcall_init(c, &req->rc, alloc_msize))
280 		goto free;
281 
282 	p9pdu_reset(&req->tc);
283 	p9pdu_reset(&req->rc);
284 	req->t_err = 0;
285 	req->status = REQ_STATUS_ALLOC;
286 	init_waitqueue_head(&req->wq);
287 	INIT_LIST_HEAD(&req->req_list);
288 
289 	idr_preload(GFP_NOFS);
290 	spin_lock_irq(&c->lock);
291 	if (type == P9_TVERSION)
292 		tag = idr_alloc(&c->reqs, req, P9_NOTAG, P9_NOTAG + 1,
293 				GFP_NOWAIT);
294 	else
295 		tag = idr_alloc(&c->reqs, req, 0, P9_NOTAG, GFP_NOWAIT);
296 	req->tc.tag = tag;
297 	spin_unlock_irq(&c->lock);
298 	idr_preload_end();
299 	if (tag < 0)
300 		goto free;
301 
302 	/* Init ref to two because in the general case there is one ref
303 	 * that is put asynchronously by a writer thread, one ref
304 	 * temporarily given by p9_tag_lookup and put by p9_client_cb
305 	 * in the recv thread, and one ref put by p9_tag_remove in the
306 	 * main thread. The only exception is virtio that does not use
307 	 * p9_tag_lookup but does not have a writer thread either
308 	 * (the write happens synchronously in the request/zc_request
309 	 * callback), so p9_client_cb eats the second ref there
310 	 * as the pointer is duplicated directly by virtqueue_add_sgs()
311 	 */
312 	refcount_set(&req->refcount.refcount, 2);
313 
314 	return req;
315 
316 free:
317 	p9_fcall_fini(&req->tc);
318 	p9_fcall_fini(&req->rc);
319 free_req:
320 	kmem_cache_free(p9_req_cache, req);
321 	return ERR_PTR(-ENOMEM);
322 }
323 
324 /**
325  * p9_tag_lookup - Look up a request by tag.
326  * @c: Client session.
327  * @tag: Transaction ID.
328  *
329  * Context: Any context.
330  * Return: A request, or %NULL if there is no request with that tag.
331  */
332 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
333 {
334 	struct p9_req_t *req;
335 
336 	rcu_read_lock();
337 again:
338 	req = idr_find(&c->reqs, tag);
339 	if (req) {
340 		/* We have to be careful with the req found under rcu_read_lock
341 		 * Thanks to SLAB_TYPESAFE_BY_RCU we can safely try to get the
342 		 * ref again without corrupting other data, then check again
343 		 * that the tag matches once we have the ref
344 		 */
345 		if (!p9_req_try_get(req))
346 			goto again;
347 		if (req->tc.tag != tag) {
348 			p9_req_put(req);
349 			goto again;
350 		}
351 	}
352 	rcu_read_unlock();
353 
354 	return req;
355 }
356 EXPORT_SYMBOL(p9_tag_lookup);
357 
358 /**
359  * p9_tag_remove - Remove a tag.
360  * @c: Client session.
361  * @r: Request of reference.
362  *
363  * Context: Any context.
364  */
365 static int p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
366 {
367 	unsigned long flags;
368 	u16 tag = r->tc.tag;
369 
370 	p9_debug(P9_DEBUG_MUX, "clnt %p req %p tag: %d\n", c, r, tag);
371 	spin_lock_irqsave(&c->lock, flags);
372 	idr_remove(&c->reqs, tag);
373 	spin_unlock_irqrestore(&c->lock, flags);
374 	return p9_req_put(r);
375 }
376 
377 static void p9_req_free(struct kref *ref)
378 {
379 	struct p9_req_t *r = container_of(ref, struct p9_req_t, refcount);
380 	p9_fcall_fini(&r->tc);
381 	p9_fcall_fini(&r->rc);
382 	kmem_cache_free(p9_req_cache, r);
383 }
384 
385 int p9_req_put(struct p9_req_t *r)
386 {
387 	return kref_put(&r->refcount, p9_req_free);
388 }
389 EXPORT_SYMBOL(p9_req_put);
390 
391 /**
392  * p9_tag_cleanup - cleans up tags structure and reclaims resources
393  * @c:  v9fs client struct
394  *
395  * This frees resources associated with the tags structure
396  *
397  */
398 static void p9_tag_cleanup(struct p9_client *c)
399 {
400 	struct p9_req_t *req;
401 	int id;
402 
403 	rcu_read_lock();
404 	idr_for_each_entry(&c->reqs, req, id) {
405 		pr_info("Tag %d still in use\n", id);
406 		if (p9_tag_remove(c, req) == 0)
407 			pr_warn("Packet with tag %d has still references",
408 				req->tc.tag);
409 	}
410 	rcu_read_unlock();
411 }
412 
413 /**
414  * p9_client_cb - call back from transport to client
415  * @c: client state
416  * @req: request received
417  * @status: request status, one of REQ_STATUS_*
418  *
419  */
420 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
421 {
422 	p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc.tag);
423 
424 	/*
425 	 * This barrier is needed to make sure any change made to req before
426 	 * the status change is visible to another thread
427 	 */
428 	smp_wmb();
429 	req->status = status;
430 
431 	wake_up(&req->wq);
432 	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
433 	p9_req_put(req);
434 }
435 EXPORT_SYMBOL(p9_client_cb);
436 
437 /**
438  * p9_parse_header - parse header arguments out of a packet
439  * @pdu: packet to parse
440  * @size: size of packet
441  * @type: type of request
442  * @tag: tag of packet
443  * @rewind: set if we need to rewind offset afterwards
444  */
445 
446 int
447 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type, int16_t *tag,
448 								int rewind)
449 {
450 	int8_t r_type;
451 	int16_t r_tag;
452 	int32_t r_size;
453 	int offset = pdu->offset;
454 	int err;
455 
456 	pdu->offset = 0;
457 
458 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
459 	if (err)
460 		goto rewind_and_exit;
461 
462 	if (type)
463 		*type = r_type;
464 	if (tag)
465 		*tag = r_tag;
466 	if (size)
467 		*size = r_size;
468 
469 	if (pdu->size != r_size || r_size < 7) {
470 		err = -EINVAL;
471 		goto rewind_and_exit;
472 	}
473 
474 	pdu->id = r_type;
475 	pdu->tag = r_tag;
476 
477 	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
478 		 pdu->size, pdu->id, pdu->tag);
479 
480 rewind_and_exit:
481 	if (rewind)
482 		pdu->offset = offset;
483 	return err;
484 }
485 EXPORT_SYMBOL(p9_parse_header);
486 
487 /**
488  * p9_check_errors - check 9p packet for error return and process it
489  * @c: current client instance
490  * @req: request to parse and check for error conditions
491  *
492  * returns error code if one is discovered, otherwise returns 0
493  *
494  * this will have to be more complicated if we have multiple
495  * error packet types
496  */
497 
498 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
499 {
500 	int8_t type;
501 	int err;
502 	int ecode;
503 
504 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
505 	if (req->rc.size >= c->msize) {
506 		p9_debug(P9_DEBUG_ERROR,
507 			 "requested packet size too big: %d\n",
508 			 req->rc.size);
509 		return -EIO;
510 	}
511 	/*
512 	 * dump the response from server
513 	 * This should be after check errors which poplulate pdu_fcall.
514 	 */
515 	trace_9p_protocol_dump(c, &req->rc);
516 	if (err) {
517 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
518 		return err;
519 	}
520 	if (type != P9_RERROR && type != P9_RLERROR)
521 		return 0;
522 
523 	if (!p9_is_proto_dotl(c)) {
524 		char *ename;
525 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
526 				  &ename, &ecode);
527 		if (err)
528 			goto out_err;
529 
530 		if (p9_is_proto_dotu(c) && ecode < 512)
531 			err = -ecode;
532 
533 		if (!err) {
534 			err = p9_errstr2errno(ename, strlen(ename));
535 
536 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
537 				 -ecode, ename);
538 		}
539 		kfree(ename);
540 	} else {
541 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
542 		err = -ecode;
543 
544 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
545 	}
546 
547 	return err;
548 
549 out_err:
550 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
551 
552 	return err;
553 }
554 
555 /**
556  * p9_check_zc_errors - check 9p packet for error return and process it
557  * @c: current client instance
558  * @req: request to parse and check for error conditions
559  * @uidata: external buffer containing error
560  * @in_hdrlen: Size of response protocol buffer.
561  *
562  * returns error code if one is discovered, otherwise returns 0
563  *
564  * this will have to be more complicated if we have multiple
565  * error packet types
566  */
567 
568 static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
569 			      struct iov_iter *uidata, int in_hdrlen)
570 {
571 	int err;
572 	int ecode;
573 	int8_t type;
574 	char *ename = NULL;
575 
576 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
577 	/*
578 	 * dump the response from server
579 	 * This should be after parse_header which poplulate pdu_fcall.
580 	 */
581 	trace_9p_protocol_dump(c, &req->rc);
582 	if (err) {
583 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
584 		return err;
585 	}
586 
587 	if (type != P9_RERROR && type != P9_RLERROR)
588 		return 0;
589 
590 	if (!p9_is_proto_dotl(c)) {
591 		/* Error is reported in string format */
592 		int len;
593 		/* 7 = header size for RERROR; */
594 		int inline_len = in_hdrlen - 7;
595 
596 		len = req->rc.size - req->rc.offset;
597 		if (len > (P9_ZC_HDR_SZ - 7)) {
598 			err = -EFAULT;
599 			goto out_err;
600 		}
601 
602 		ename = &req->rc.sdata[req->rc.offset];
603 		if (len > inline_len) {
604 			/* We have error in external buffer */
605 			if (!copy_from_iter_full(ename + inline_len,
606 					     len - inline_len, uidata)) {
607 				err = -EFAULT;
608 				goto out_err;
609 			}
610 		}
611 		ename = NULL;
612 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
613 				  &ename, &ecode);
614 		if (err)
615 			goto out_err;
616 
617 		if (p9_is_proto_dotu(c) && ecode < 512)
618 			err = -ecode;
619 
620 		if (!err) {
621 			err = p9_errstr2errno(ename, strlen(ename));
622 
623 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
624 				 -ecode, ename);
625 		}
626 		kfree(ename);
627 	} else {
628 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
629 		err = -ecode;
630 
631 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
632 	}
633 	return err;
634 
635 out_err:
636 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
637 	return err;
638 }
639 
640 static struct p9_req_t *
641 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
642 
643 /**
644  * p9_client_flush - flush (cancel) a request
645  * @c: client state
646  * @oldreq: request to cancel
647  *
648  * This sents a flush for a particular request and links
649  * the flush request to the original request.  The current
650  * code only supports a single flush request although the protocol
651  * allows for multiple flush requests to be sent for a single request.
652  *
653  */
654 
655 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
656 {
657 	struct p9_req_t *req;
658 	int16_t oldtag;
659 	int err;
660 
661 	err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
662 	if (err)
663 		return err;
664 
665 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
666 
667 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
668 	if (IS_ERR(req))
669 		return PTR_ERR(req);
670 
671 	/*
672 	 * if we haven't received a response for oldreq,
673 	 * remove it from the list
674 	 */
675 	if (oldreq->status == REQ_STATUS_SENT) {
676 		if (c->trans_mod->cancelled)
677 			c->trans_mod->cancelled(c, oldreq);
678 	}
679 
680 	p9_tag_remove(c, req);
681 	return 0;
682 }
683 
684 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
685 					      int8_t type, int req_size,
686 					      const char *fmt, va_list ap)
687 {
688 	int err;
689 	struct p9_req_t *req;
690 
691 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
692 
693 	/* we allow for any status other than disconnected */
694 	if (c->status == Disconnected)
695 		return ERR_PTR(-EIO);
696 
697 	/* if status is begin_disconnected we allow only clunk request */
698 	if ((c->status == BeginDisconnect) && (type != P9_TCLUNK))
699 		return ERR_PTR(-EIO);
700 
701 	req = p9_tag_alloc(c, type, req_size);
702 	if (IS_ERR(req))
703 		return req;
704 
705 	/* marshall the data */
706 	p9pdu_prepare(&req->tc, req->tc.tag, type);
707 	err = p9pdu_vwritef(&req->tc, c->proto_version, fmt, ap);
708 	if (err)
709 		goto reterr;
710 	p9pdu_finalize(c, &req->tc);
711 	trace_9p_client_req(c, type, req->tc.tag);
712 	return req;
713 reterr:
714 	p9_tag_remove(c, req);
715 	/* We have to put also the 2nd reference as it won't be used */
716 	p9_req_put(req);
717 	return ERR_PTR(err);
718 }
719 
720 /**
721  * p9_client_rpc - issue a request and wait for a response
722  * @c: client session
723  * @type: type of request
724  * @fmt: protocol format string (see protocol.c)
725  *
726  * Returns request structure (which client must free using p9_tag_remove)
727  */
728 
729 static struct p9_req_t *
730 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
731 {
732 	va_list ap;
733 	int sigpending, err;
734 	unsigned long flags;
735 	struct p9_req_t *req;
736 
737 	va_start(ap, fmt);
738 	req = p9_client_prepare_req(c, type, c->msize, fmt, ap);
739 	va_end(ap);
740 	if (IS_ERR(req))
741 		return req;
742 
743 	if (signal_pending(current)) {
744 		sigpending = 1;
745 		clear_thread_flag(TIF_SIGPENDING);
746 	} else
747 		sigpending = 0;
748 
749 	err = c->trans_mod->request(c, req);
750 	if (err < 0) {
751 		/* write won't happen */
752 		p9_req_put(req);
753 		if (err != -ERESTARTSYS && err != -EFAULT)
754 			c->status = Disconnected;
755 		goto recalc_sigpending;
756 	}
757 again:
758 	/* Wait for the response */
759 	err = wait_event_killable(req->wq, req->status >= REQ_STATUS_RCVD);
760 
761 	/*
762 	 * Make sure our req is coherent with regard to updates in other
763 	 * threads - echoes to wmb() in the callback
764 	 */
765 	smp_rmb();
766 
767 	if ((err == -ERESTARTSYS) && (c->status == Connected)
768 				  && (type == P9_TFLUSH)) {
769 		sigpending = 1;
770 		clear_thread_flag(TIF_SIGPENDING);
771 		goto again;
772 	}
773 
774 	if (req->status == REQ_STATUS_ERROR) {
775 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
776 		err = req->t_err;
777 	}
778 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
779 		p9_debug(P9_DEBUG_MUX, "flushing\n");
780 		sigpending = 1;
781 		clear_thread_flag(TIF_SIGPENDING);
782 
783 		if (c->trans_mod->cancel(c, req))
784 			p9_client_flush(c, req);
785 
786 		/* if we received the response anyway, don't signal error */
787 		if (req->status == REQ_STATUS_RCVD)
788 			err = 0;
789 	}
790 recalc_sigpending:
791 	if (sigpending) {
792 		spin_lock_irqsave(&current->sighand->siglock, flags);
793 		recalc_sigpending();
794 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
795 	}
796 	if (err < 0)
797 		goto reterr;
798 
799 	err = p9_check_errors(c, req);
800 	trace_9p_client_res(c, type, req->rc.tag, err);
801 	if (!err)
802 		return req;
803 reterr:
804 	p9_tag_remove(c, req);
805 	return ERR_PTR(safe_errno(err));
806 }
807 
808 /**
809  * p9_client_zc_rpc - issue a request and wait for a response
810  * @c: client session
811  * @type: type of request
812  * @uidata: destination for zero copy read
813  * @uodata: source for zero copy write
814  * @inlen: read buffer size
815  * @olen: write buffer size
816  * @in_hdrlen: reader header size, This is the size of response protocol data
817  * @fmt: protocol format string (see protocol.c)
818  *
819  * Returns request structure (which client must free using p9_tag_remove)
820  */
821 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
822 					 struct iov_iter *uidata,
823 					 struct iov_iter *uodata,
824 					 int inlen, int olen, int in_hdrlen,
825 					 const char *fmt, ...)
826 {
827 	va_list ap;
828 	int sigpending, err;
829 	unsigned long flags;
830 	struct p9_req_t *req;
831 
832 	va_start(ap, fmt);
833 	/*
834 	 * We allocate a inline protocol data of only 4k bytes.
835 	 * The actual content is passed in zero-copy fashion.
836 	 */
837 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, fmt, ap);
838 	va_end(ap);
839 	if (IS_ERR(req))
840 		return req;
841 
842 	if (signal_pending(current)) {
843 		sigpending = 1;
844 		clear_thread_flag(TIF_SIGPENDING);
845 	} else
846 		sigpending = 0;
847 
848 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
849 				       inlen, olen, in_hdrlen);
850 	if (err < 0) {
851 		if (err == -EIO)
852 			c->status = Disconnected;
853 		if (err != -ERESTARTSYS)
854 			goto recalc_sigpending;
855 	}
856 	if (req->status == REQ_STATUS_ERROR) {
857 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
858 		err = req->t_err;
859 	}
860 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
861 		p9_debug(P9_DEBUG_MUX, "flushing\n");
862 		sigpending = 1;
863 		clear_thread_flag(TIF_SIGPENDING);
864 
865 		if (c->trans_mod->cancel(c, req))
866 			p9_client_flush(c, req);
867 
868 		/* if we received the response anyway, don't signal error */
869 		if (req->status == REQ_STATUS_RCVD)
870 			err = 0;
871 	}
872 recalc_sigpending:
873 	if (sigpending) {
874 		spin_lock_irqsave(&current->sighand->siglock, flags);
875 		recalc_sigpending();
876 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
877 	}
878 	if (err < 0)
879 		goto reterr;
880 
881 	err = p9_check_zc_errors(c, req, uidata, in_hdrlen);
882 	trace_9p_client_res(c, type, req->rc.tag, err);
883 	if (!err)
884 		return req;
885 reterr:
886 	p9_tag_remove(c, req);
887 	return ERR_PTR(safe_errno(err));
888 }
889 
890 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
891 {
892 	int ret;
893 	struct p9_fid *fid;
894 
895 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
896 	fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
897 	if (!fid)
898 		return NULL;
899 
900 	memset(&fid->qid, 0, sizeof(struct p9_qid));
901 	fid->mode = -1;
902 	fid->uid = current_fsuid();
903 	fid->clnt = clnt;
904 	fid->rdir = NULL;
905 	fid->fid = 0;
906 	refcount_set(&fid->count, 1);
907 
908 	idr_preload(GFP_KERNEL);
909 	spin_lock_irq(&clnt->lock);
910 	ret = idr_alloc_u32(&clnt->fids, fid, &fid->fid, P9_NOFID - 1,
911 			    GFP_NOWAIT);
912 	spin_unlock_irq(&clnt->lock);
913 	idr_preload_end();
914 	if (!ret)
915 		return fid;
916 
917 	kfree(fid);
918 	return NULL;
919 }
920 
921 static void p9_fid_destroy(struct p9_fid *fid)
922 {
923 	struct p9_client *clnt;
924 	unsigned long flags;
925 
926 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
927 	clnt = fid->clnt;
928 	spin_lock_irqsave(&clnt->lock, flags);
929 	idr_remove(&clnt->fids, fid->fid);
930 	spin_unlock_irqrestore(&clnt->lock, flags);
931 	kfree(fid->rdir);
932 	kfree(fid);
933 }
934 
935 static int p9_client_version(struct p9_client *c)
936 {
937 	int err = 0;
938 	struct p9_req_t *req;
939 	char *version = NULL;
940 	int msize;
941 
942 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
943 		 c->msize, c->proto_version);
944 
945 	switch (c->proto_version) {
946 	case p9_proto_2000L:
947 		req = p9_client_rpc(c, P9_TVERSION, "ds",
948 					c->msize, "9P2000.L");
949 		break;
950 	case p9_proto_2000u:
951 		req = p9_client_rpc(c, P9_TVERSION, "ds",
952 					c->msize, "9P2000.u");
953 		break;
954 	case p9_proto_legacy:
955 		req = p9_client_rpc(c, P9_TVERSION, "ds",
956 					c->msize, "9P2000");
957 		break;
958 	default:
959 		return -EINVAL;
960 	}
961 
962 	if (IS_ERR(req))
963 		return PTR_ERR(req);
964 
965 	err = p9pdu_readf(&req->rc, c->proto_version, "ds", &msize, &version);
966 	if (err) {
967 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
968 		trace_9p_protocol_dump(c, &req->rc);
969 		goto error;
970 	}
971 
972 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
973 	if (!strncmp(version, "9P2000.L", 8))
974 		c->proto_version = p9_proto_2000L;
975 	else if (!strncmp(version, "9P2000.u", 8))
976 		c->proto_version = p9_proto_2000u;
977 	else if (!strncmp(version, "9P2000", 6))
978 		c->proto_version = p9_proto_legacy;
979 	else {
980 		p9_debug(P9_DEBUG_ERROR,
981 			 "server returned an unknown version: %s\n", version);
982 		err = -EREMOTEIO;
983 		goto error;
984 	}
985 
986 	if (msize < 4096) {
987 		p9_debug(P9_DEBUG_ERROR,
988 			 "server returned a msize < 4096: %d\n", msize);
989 		err = -EREMOTEIO;
990 		goto error;
991 	}
992 	if (msize < c->msize)
993 		c->msize = msize;
994 
995 error:
996 	kfree(version);
997 	p9_tag_remove(c, req);
998 
999 	return err;
1000 }
1001 
1002 struct p9_client *p9_client_create(const char *dev_name, char *options)
1003 {
1004 	int err;
1005 	struct p9_client *clnt;
1006 	char *client_id;
1007 
1008 	err = 0;
1009 	clnt = kmalloc(sizeof(struct p9_client), GFP_KERNEL);
1010 	if (!clnt)
1011 		return ERR_PTR(-ENOMEM);
1012 
1013 	clnt->trans_mod = NULL;
1014 	clnt->trans = NULL;
1015 	clnt->fcall_cache = NULL;
1016 
1017 	client_id = utsname()->nodename;
1018 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
1019 
1020 	spin_lock_init(&clnt->lock);
1021 	idr_init(&clnt->fids);
1022 	idr_init(&clnt->reqs);
1023 
1024 	err = parse_opts(options, clnt);
1025 	if (err < 0)
1026 		goto free_client;
1027 
1028 	if (!clnt->trans_mod)
1029 		clnt->trans_mod = v9fs_get_default_trans();
1030 
1031 	if (clnt->trans_mod == NULL) {
1032 		err = -EPROTONOSUPPORT;
1033 		p9_debug(P9_DEBUG_ERROR,
1034 			 "No transport defined or default transport\n");
1035 		goto free_client;
1036 	}
1037 
1038 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
1039 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
1040 
1041 	err = clnt->trans_mod->create(clnt, dev_name, options);
1042 	if (err)
1043 		goto put_trans;
1044 
1045 	if (clnt->msize > clnt->trans_mod->maxsize)
1046 		clnt->msize = clnt->trans_mod->maxsize;
1047 
1048 	if (clnt->msize < 4096) {
1049 		p9_debug(P9_DEBUG_ERROR,
1050 			 "Please specify a msize of at least 4k\n");
1051 		err = -EINVAL;
1052 		goto close_trans;
1053 	}
1054 
1055 	err = p9_client_version(clnt);
1056 	if (err)
1057 		goto close_trans;
1058 
1059 	/* P9_HDRSZ + 4 is the smallest packet header we can have that is
1060 	 * followed by data accessed from userspace by read
1061 	 */
1062 	clnt->fcall_cache =
1063 		kmem_cache_create_usercopy("9p-fcall-cache", clnt->msize,
1064 					   0, 0, P9_HDRSZ + 4,
1065 					   clnt->msize - (P9_HDRSZ + 4),
1066 					   NULL);
1067 
1068 	return clnt;
1069 
1070 close_trans:
1071 	clnt->trans_mod->close(clnt);
1072 put_trans:
1073 	v9fs_put_trans(clnt->trans_mod);
1074 free_client:
1075 	kfree(clnt);
1076 	return ERR_PTR(err);
1077 }
1078 EXPORT_SYMBOL(p9_client_create);
1079 
1080 void p9_client_destroy(struct p9_client *clnt)
1081 {
1082 	struct p9_fid *fid;
1083 	int id;
1084 
1085 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1086 
1087 	if (clnt->trans_mod)
1088 		clnt->trans_mod->close(clnt);
1089 
1090 	v9fs_put_trans(clnt->trans_mod);
1091 
1092 	idr_for_each_entry(&clnt->fids, fid, id) {
1093 		pr_info("Found fid %d not clunked\n", fid->fid);
1094 		p9_fid_destroy(fid);
1095 	}
1096 
1097 	p9_tag_cleanup(clnt);
1098 
1099 	kmem_cache_destroy(clnt->fcall_cache);
1100 	kfree(clnt);
1101 }
1102 EXPORT_SYMBOL(p9_client_destroy);
1103 
1104 void p9_client_disconnect(struct p9_client *clnt)
1105 {
1106 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1107 	clnt->status = Disconnected;
1108 }
1109 EXPORT_SYMBOL(p9_client_disconnect);
1110 
1111 void p9_client_begin_disconnect(struct p9_client *clnt)
1112 {
1113 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1114 	clnt->status = BeginDisconnect;
1115 }
1116 EXPORT_SYMBOL(p9_client_begin_disconnect);
1117 
1118 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1119 	const char *uname, kuid_t n_uname, const char *aname)
1120 {
1121 	int err = 0;
1122 	struct p9_req_t *req;
1123 	struct p9_fid *fid;
1124 	struct p9_qid qid;
1125 
1126 
1127 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1128 		 afid ? afid->fid : -1, uname, aname);
1129 	fid = p9_fid_create(clnt);
1130 	if (!fid) {
1131 		err = -ENOMEM;
1132 		goto error;
1133 	}
1134 	fid->uid = n_uname;
1135 
1136 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
1137 			afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
1138 	if (IS_ERR(req)) {
1139 		err = PTR_ERR(req);
1140 		goto error;
1141 	}
1142 
1143 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", &qid);
1144 	if (err) {
1145 		trace_9p_protocol_dump(clnt, &req->rc);
1146 		p9_tag_remove(clnt, req);
1147 		goto error;
1148 	}
1149 
1150 	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
1151 		 qid.type, (unsigned long long)qid.path, qid.version);
1152 
1153 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1154 
1155 	p9_tag_remove(clnt, req);
1156 	return fid;
1157 
1158 error:
1159 	if (fid)
1160 		p9_fid_destroy(fid);
1161 	return ERR_PTR(err);
1162 }
1163 EXPORT_SYMBOL(p9_client_attach);
1164 
1165 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
1166 		const unsigned char * const *wnames, int clone)
1167 {
1168 	int err;
1169 	struct p9_client *clnt;
1170 	struct p9_fid *fid;
1171 	struct p9_qid *wqids;
1172 	struct p9_req_t *req;
1173 	uint16_t nwqids, count;
1174 
1175 	err = 0;
1176 	wqids = NULL;
1177 	clnt = oldfid->clnt;
1178 	if (clone) {
1179 		fid = p9_fid_create(clnt);
1180 		if (!fid) {
1181 			err = -ENOMEM;
1182 			goto error;
1183 		}
1184 
1185 		fid->uid = oldfid->uid;
1186 	} else
1187 		fid = oldfid;
1188 
1189 
1190 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1191 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1192 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1193 								nwname, wnames);
1194 	if (IS_ERR(req)) {
1195 		err = PTR_ERR(req);
1196 		goto error;
1197 	}
1198 
1199 	err = p9pdu_readf(&req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1200 	if (err) {
1201 		trace_9p_protocol_dump(clnt, &req->rc);
1202 		p9_tag_remove(clnt, req);
1203 		goto clunk_fid;
1204 	}
1205 	p9_tag_remove(clnt, req);
1206 
1207 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1208 
1209 	if (nwqids != nwname) {
1210 		err = -ENOENT;
1211 		goto clunk_fid;
1212 	}
1213 
1214 	for (count = 0; count < nwqids; count++)
1215 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1216 			count, wqids[count].type,
1217 			(unsigned long long)wqids[count].path,
1218 			wqids[count].version);
1219 
1220 	if (nwname)
1221 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1222 	else
1223 		memmove(&fid->qid, &oldfid->qid, sizeof(struct p9_qid));
1224 
1225 	kfree(wqids);
1226 	return fid;
1227 
1228 clunk_fid:
1229 	kfree(wqids);
1230 	p9_client_clunk(fid);
1231 	fid = NULL;
1232 
1233 error:
1234 	if (fid && (fid != oldfid))
1235 		p9_fid_destroy(fid);
1236 
1237 	return ERR_PTR(err);
1238 }
1239 EXPORT_SYMBOL(p9_client_walk);
1240 
1241 int p9_client_open(struct p9_fid *fid, int mode)
1242 {
1243 	int err;
1244 	struct p9_client *clnt;
1245 	struct p9_req_t *req;
1246 	struct p9_qid qid;
1247 	int iounit;
1248 
1249 	clnt = fid->clnt;
1250 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1251 		p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1252 	err = 0;
1253 
1254 	if (fid->mode != -1)
1255 		return -EINVAL;
1256 
1257 	if (p9_is_proto_dotl(clnt))
1258 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode);
1259 	else
1260 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
1261 	if (IS_ERR(req)) {
1262 		err = PTR_ERR(req);
1263 		goto error;
1264 	}
1265 
1266 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1267 	if (err) {
1268 		trace_9p_protocol_dump(clnt, &req->rc);
1269 		goto free_and_error;
1270 	}
1271 
1272 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1273 		p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1274 		(unsigned long long)qid.path, qid.version, iounit);
1275 
1276 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1277 	fid->mode = mode;
1278 	fid->iounit = iounit;
1279 
1280 free_and_error:
1281 	p9_tag_remove(clnt, req);
1282 error:
1283 	return err;
1284 }
1285 EXPORT_SYMBOL(p9_client_open);
1286 
1287 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags, u32 mode,
1288 		kgid_t gid, struct p9_qid *qid)
1289 {
1290 	int err = 0;
1291 	struct p9_client *clnt;
1292 	struct p9_req_t *req;
1293 	int iounit;
1294 
1295 	p9_debug(P9_DEBUG_9P,
1296 			">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1297 			ofid->fid, name, flags, mode,
1298 		 	from_kgid(&init_user_ns, gid));
1299 	clnt = ofid->clnt;
1300 
1301 	if (ofid->mode != -1)
1302 		return -EINVAL;
1303 
1304 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1305 			mode, gid);
1306 	if (IS_ERR(req)) {
1307 		err = PTR_ERR(req);
1308 		goto error;
1309 	}
1310 
1311 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", qid, &iounit);
1312 	if (err) {
1313 		trace_9p_protocol_dump(clnt, &req->rc);
1314 		goto free_and_error;
1315 	}
1316 
1317 	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1318 			qid->type,
1319 			(unsigned long long)qid->path,
1320 			qid->version, iounit);
1321 
1322 	memmove(&ofid->qid, qid, sizeof(struct p9_qid));
1323 	ofid->mode = mode;
1324 	ofid->iounit = iounit;
1325 
1326 free_and_error:
1327 	p9_tag_remove(clnt, req);
1328 error:
1329 	return err;
1330 }
1331 EXPORT_SYMBOL(p9_client_create_dotl);
1332 
1333 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1334 		     char *extension)
1335 {
1336 	int err;
1337 	struct p9_client *clnt;
1338 	struct p9_req_t *req;
1339 	struct p9_qid qid;
1340 	int iounit;
1341 
1342 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1343 						fid->fid, name, perm, mode);
1344 	err = 0;
1345 	clnt = fid->clnt;
1346 
1347 	if (fid->mode != -1)
1348 		return -EINVAL;
1349 
1350 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1351 				mode, extension);
1352 	if (IS_ERR(req)) {
1353 		err = PTR_ERR(req);
1354 		goto error;
1355 	}
1356 
1357 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1358 	if (err) {
1359 		trace_9p_protocol_dump(clnt, &req->rc);
1360 		goto free_and_error;
1361 	}
1362 
1363 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1364 				qid.type,
1365 				(unsigned long long)qid.path,
1366 				qid.version, iounit);
1367 
1368 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1369 	fid->mode = mode;
1370 	fid->iounit = iounit;
1371 
1372 free_and_error:
1373 	p9_tag_remove(clnt, req);
1374 error:
1375 	return err;
1376 }
1377 EXPORT_SYMBOL(p9_client_fcreate);
1378 
1379 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1380 		const char *symtgt, kgid_t gid, struct p9_qid *qid)
1381 {
1382 	int err = 0;
1383 	struct p9_client *clnt;
1384 	struct p9_req_t *req;
1385 
1386 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1387 			dfid->fid, name, symtgt);
1388 	clnt = dfid->clnt;
1389 
1390 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1391 			gid);
1392 	if (IS_ERR(req)) {
1393 		err = PTR_ERR(req);
1394 		goto error;
1395 	}
1396 
1397 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
1398 	if (err) {
1399 		trace_9p_protocol_dump(clnt, &req->rc);
1400 		goto free_and_error;
1401 	}
1402 
1403 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1404 			qid->type, (unsigned long long)qid->path, qid->version);
1405 
1406 free_and_error:
1407 	p9_tag_remove(clnt, req);
1408 error:
1409 	return err;
1410 }
1411 EXPORT_SYMBOL(p9_client_symlink);
1412 
1413 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1414 {
1415 	struct p9_client *clnt;
1416 	struct p9_req_t *req;
1417 
1418 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1419 			dfid->fid, oldfid->fid, newname);
1420 	clnt = dfid->clnt;
1421 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1422 			newname);
1423 	if (IS_ERR(req))
1424 		return PTR_ERR(req);
1425 
1426 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1427 	p9_tag_remove(clnt, req);
1428 	return 0;
1429 }
1430 EXPORT_SYMBOL(p9_client_link);
1431 
1432 int p9_client_fsync(struct p9_fid *fid, int datasync)
1433 {
1434 	int err;
1435 	struct p9_client *clnt;
1436 	struct p9_req_t *req;
1437 
1438 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1439 			fid->fid, datasync);
1440 	err = 0;
1441 	clnt = fid->clnt;
1442 
1443 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1444 	if (IS_ERR(req)) {
1445 		err = PTR_ERR(req);
1446 		goto error;
1447 	}
1448 
1449 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1450 
1451 	p9_tag_remove(clnt, req);
1452 
1453 error:
1454 	return err;
1455 }
1456 EXPORT_SYMBOL(p9_client_fsync);
1457 
1458 int p9_client_clunk(struct p9_fid *fid)
1459 {
1460 	int err;
1461 	struct p9_client *clnt;
1462 	struct p9_req_t *req;
1463 	int retries = 0;
1464 
1465 	if (!fid || IS_ERR(fid)) {
1466 		pr_warn("%s (%d): Trying to clunk with invalid fid\n",
1467 			__func__, task_pid_nr(current));
1468 		dump_stack();
1469 		return 0;
1470 	}
1471 	if (!refcount_dec_and_test(&fid->count))
1472 		return 0;
1473 
1474 again:
1475 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n", fid->fid,
1476 								retries);
1477 	err = 0;
1478 	clnt = fid->clnt;
1479 
1480 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1481 	if (IS_ERR(req)) {
1482 		err = PTR_ERR(req);
1483 		goto error;
1484 	}
1485 
1486 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1487 
1488 	p9_tag_remove(clnt, req);
1489 error:
1490 	/*
1491 	 * Fid is not valid even after a failed clunk
1492 	 * If interrupted, retry once then give up and
1493 	 * leak fid until umount.
1494 	 */
1495 	if (err == -ERESTARTSYS) {
1496 		if (retries++ == 0)
1497 			goto again;
1498 	} else
1499 		p9_fid_destroy(fid);
1500 	return err;
1501 }
1502 EXPORT_SYMBOL(p9_client_clunk);
1503 
1504 int p9_client_remove(struct p9_fid *fid)
1505 {
1506 	int err;
1507 	struct p9_client *clnt;
1508 	struct p9_req_t *req;
1509 
1510 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1511 	err = 0;
1512 	clnt = fid->clnt;
1513 
1514 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1515 	if (IS_ERR(req)) {
1516 		err = PTR_ERR(req);
1517 		goto error;
1518 	}
1519 
1520 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1521 
1522 	p9_tag_remove(clnt, req);
1523 error:
1524 	if (err == -ERESTARTSYS)
1525 		p9_client_clunk(fid);
1526 	else
1527 		p9_fid_destroy(fid);
1528 	return err;
1529 }
1530 EXPORT_SYMBOL(p9_client_remove);
1531 
1532 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1533 {
1534 	int err = 0;
1535 	struct p9_req_t *req;
1536 	struct p9_client *clnt;
1537 
1538 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1539 		   dfid->fid, name, flags);
1540 
1541 	clnt = dfid->clnt;
1542 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1543 	if (IS_ERR(req)) {
1544 		err = PTR_ERR(req);
1545 		goto error;
1546 	}
1547 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1548 
1549 	p9_tag_remove(clnt, req);
1550 error:
1551 	return err;
1552 }
1553 EXPORT_SYMBOL(p9_client_unlinkat);
1554 
1555 int
1556 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1557 {
1558 	int total = 0;
1559 	*err = 0;
1560 
1561 	while (iov_iter_count(to)) {
1562 		int count;
1563 
1564 		count = p9_client_read_once(fid, offset, to, err);
1565 		if (!count || *err)
1566 			break;
1567 		offset += count;
1568 		total += count;
1569 	}
1570 	return total;
1571 }
1572 EXPORT_SYMBOL(p9_client_read);
1573 
1574 int
1575 p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
1576 		    int *err)
1577 {
1578 	struct p9_client *clnt = fid->clnt;
1579 	struct p9_req_t *req;
1580 	int count = iov_iter_count(to);
1581 	int rsize, non_zc = 0;
1582 	char *dataptr;
1583 
1584 	*err = 0;
1585 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n",
1586 		   fid->fid, (unsigned long long) offset, (int)iov_iter_count(to));
1587 
1588 	rsize = fid->iounit;
1589 	if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1590 		rsize = clnt->msize - P9_IOHDRSZ;
1591 
1592 	if (count < rsize)
1593 		rsize = count;
1594 
1595 	/* Don't bother zerocopy for small IO (< 1024) */
1596 	if (clnt->trans_mod->zc_request && rsize > 1024) {
1597 		/* response header len is 11
1598 		 * PDU Header(7) + IO Size (4)
1599 		 */
1600 		req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1601 				       0, 11, "dqd", fid->fid,
1602 				       offset, rsize);
1603 	} else {
1604 		non_zc = 1;
1605 		req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1606 				    rsize);
1607 	}
1608 	if (IS_ERR(req)) {
1609 		*err = PTR_ERR(req);
1610 		return 0;
1611 	}
1612 
1613 	*err = p9pdu_readf(&req->rc, clnt->proto_version,
1614 			   "D", &count, &dataptr);
1615 	if (*err) {
1616 		trace_9p_protocol_dump(clnt, &req->rc);
1617 		p9_tag_remove(clnt, req);
1618 		return 0;
1619 	}
1620 	if (rsize < count) {
1621 		pr_err("bogus RREAD count (%d > %d)\n", count, rsize);
1622 		count = rsize;
1623 	}
1624 
1625 	p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1626 	if (!count) {
1627 		p9_tag_remove(clnt, req);
1628 		return 0;
1629 	}
1630 
1631 	if (non_zc) {
1632 		int n = copy_to_iter(dataptr, count, to);
1633 
1634 		if (n != count) {
1635 			*err = -EFAULT;
1636 			p9_tag_remove(clnt, req);
1637 			return n;
1638 		}
1639 	} else {
1640 		iov_iter_advance(to, count);
1641 	}
1642 	p9_tag_remove(clnt, req);
1643 	return count;
1644 }
1645 EXPORT_SYMBOL(p9_client_read_once);
1646 
1647 int
1648 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1649 {
1650 	struct p9_client *clnt = fid->clnt;
1651 	struct p9_req_t *req;
1652 	int total = 0;
1653 	*err = 0;
1654 
1655 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n",
1656 				fid->fid, (unsigned long long) offset,
1657 				iov_iter_count(from));
1658 
1659 	while (iov_iter_count(from)) {
1660 		int count = iov_iter_count(from);
1661 		int rsize = fid->iounit;
1662 		if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1663 			rsize = clnt->msize - P9_IOHDRSZ;
1664 
1665 		if (count < rsize)
1666 			rsize = count;
1667 
1668 		/* Don't bother zerocopy for small IO (< 1024) */
1669 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1670 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1671 					       rsize, P9_ZC_HDR_SZ, "dqd",
1672 					       fid->fid, offset, rsize);
1673 		} else {
1674 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1675 						    offset, rsize, from);
1676 		}
1677 		if (IS_ERR(req)) {
1678 			*err = PTR_ERR(req);
1679 			break;
1680 		}
1681 
1682 		*err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &count);
1683 		if (*err) {
1684 			trace_9p_protocol_dump(clnt, &req->rc);
1685 			p9_tag_remove(clnt, req);
1686 			break;
1687 		}
1688 		if (rsize < count) {
1689 			pr_err("bogus RWRITE count (%d > %d)\n", count, rsize);
1690 			count = rsize;
1691 		}
1692 
1693 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1694 
1695 		p9_tag_remove(clnt, req);
1696 		iov_iter_advance(from, count);
1697 		total += count;
1698 		offset += count;
1699 	}
1700 	return total;
1701 }
1702 EXPORT_SYMBOL(p9_client_write);
1703 
1704 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1705 {
1706 	int err;
1707 	struct p9_client *clnt;
1708 	struct p9_wstat *ret = kmalloc(sizeof(struct p9_wstat), GFP_KERNEL);
1709 	struct p9_req_t *req;
1710 	u16 ignored;
1711 
1712 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1713 
1714 	if (!ret)
1715 		return ERR_PTR(-ENOMEM);
1716 
1717 	err = 0;
1718 	clnt = fid->clnt;
1719 
1720 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1721 	if (IS_ERR(req)) {
1722 		err = PTR_ERR(req);
1723 		goto error;
1724 	}
1725 
1726 	err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
1727 	if (err) {
1728 		trace_9p_protocol_dump(clnt, &req->rc);
1729 		p9_tag_remove(clnt, req);
1730 		goto error;
1731 	}
1732 
1733 	p9_debug(P9_DEBUG_9P,
1734 		"<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1735 		"<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1736 		"<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1737 		"<<<    uid=%d gid=%d n_muid=%d\n",
1738 		ret->size, ret->type, ret->dev, ret->qid.type,
1739 		(unsigned long long)ret->qid.path, ret->qid.version, ret->mode,
1740 		ret->atime, ret->mtime, (unsigned long long)ret->length,
1741 		ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1742 		from_kuid(&init_user_ns, ret->n_uid),
1743 		from_kgid(&init_user_ns, ret->n_gid),
1744 		from_kuid(&init_user_ns, ret->n_muid));
1745 
1746 	p9_tag_remove(clnt, req);
1747 	return ret;
1748 
1749 error:
1750 	kfree(ret);
1751 	return ERR_PTR(err);
1752 }
1753 EXPORT_SYMBOL(p9_client_stat);
1754 
1755 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1756 							u64 request_mask)
1757 {
1758 	int err;
1759 	struct p9_client *clnt;
1760 	struct p9_stat_dotl *ret = kmalloc(sizeof(struct p9_stat_dotl),
1761 								GFP_KERNEL);
1762 	struct p9_req_t *req;
1763 
1764 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1765 							fid->fid, request_mask);
1766 
1767 	if (!ret)
1768 		return ERR_PTR(-ENOMEM);
1769 
1770 	err = 0;
1771 	clnt = fid->clnt;
1772 
1773 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1774 	if (IS_ERR(req)) {
1775 		err = PTR_ERR(req);
1776 		goto error;
1777 	}
1778 
1779 	err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
1780 	if (err) {
1781 		trace_9p_protocol_dump(clnt, &req->rc);
1782 		p9_tag_remove(clnt, req);
1783 		goto error;
1784 	}
1785 
1786 	p9_debug(P9_DEBUG_9P,
1787 		"<<< RGETATTR st_result_mask=%lld\n"
1788 		"<<< qid=%x.%llx.%x\n"
1789 		"<<< st_mode=%8.8x st_nlink=%llu\n"
1790 		"<<< st_uid=%d st_gid=%d\n"
1791 		"<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1792 		"<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1793 		"<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1794 		"<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1795 		"<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1796 		"<<< st_gen=%lld st_data_version=%lld\n",
1797 		ret->st_result_mask, ret->qid.type, ret->qid.path,
1798 		ret->qid.version, ret->st_mode, ret->st_nlink,
1799 		from_kuid(&init_user_ns, ret->st_uid),
1800 		from_kgid(&init_user_ns, ret->st_gid),
1801 		ret->st_rdev, ret->st_size, ret->st_blksize,
1802 		ret->st_blocks, ret->st_atime_sec, ret->st_atime_nsec,
1803 		ret->st_mtime_sec, ret->st_mtime_nsec, ret->st_ctime_sec,
1804 		ret->st_ctime_nsec, ret->st_btime_sec, ret->st_btime_nsec,
1805 		ret->st_gen, ret->st_data_version);
1806 
1807 	p9_tag_remove(clnt, req);
1808 	return ret;
1809 
1810 error:
1811 	kfree(ret);
1812 	return ERR_PTR(err);
1813 }
1814 EXPORT_SYMBOL(p9_client_getattr_dotl);
1815 
1816 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1817 {
1818 	int ret;
1819 
1820 	/* NOTE: size shouldn't include its own length */
1821 	/* size[2] type[2] dev[4] qid[13] */
1822 	/* mode[4] atime[4] mtime[4] length[8]*/
1823 	/* name[s] uid[s] gid[s] muid[s] */
1824 	ret = 2+4+13+4+4+4+8+2+2+2+2;
1825 
1826 	if (wst->name)
1827 		ret += strlen(wst->name);
1828 	if (wst->uid)
1829 		ret += strlen(wst->uid);
1830 	if (wst->gid)
1831 		ret += strlen(wst->gid);
1832 	if (wst->muid)
1833 		ret += strlen(wst->muid);
1834 
1835 	if ((proto_version == p9_proto_2000u) ||
1836 		(proto_version == p9_proto_2000L)) {
1837 		ret += 2+4+4+4;	/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1838 		if (wst->extension)
1839 			ret += strlen(wst->extension);
1840 	}
1841 
1842 	return ret;
1843 }
1844 
1845 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1846 {
1847 	int err;
1848 	struct p9_req_t *req;
1849 	struct p9_client *clnt;
1850 
1851 	err = 0;
1852 	clnt = fid->clnt;
1853 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1854 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n", fid->fid);
1855 	p9_debug(P9_DEBUG_9P,
1856 		"     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1857 		"     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1858 		"     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1859 		"     uid=%d gid=%d n_muid=%d\n",
1860 		wst->size, wst->type, wst->dev, wst->qid.type,
1861 		(unsigned long long)wst->qid.path, wst->qid.version, wst->mode,
1862 		wst->atime, wst->mtime, (unsigned long long)wst->length,
1863 		wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1864 		from_kuid(&init_user_ns, wst->n_uid),
1865 		from_kgid(&init_user_ns, wst->n_gid),
1866 		from_kuid(&init_user_ns, wst->n_muid));
1867 
1868 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS", fid->fid, wst->size+2, wst);
1869 	if (IS_ERR(req)) {
1870 		err = PTR_ERR(req);
1871 		goto error;
1872 	}
1873 
1874 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1875 
1876 	p9_tag_remove(clnt, req);
1877 error:
1878 	return err;
1879 }
1880 EXPORT_SYMBOL(p9_client_wstat);
1881 
1882 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1883 {
1884 	int err;
1885 	struct p9_req_t *req;
1886 	struct p9_client *clnt;
1887 
1888 	err = 0;
1889 	clnt = fid->clnt;
1890 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1891 	p9_debug(P9_DEBUG_9P,
1892 		"    valid=%x mode=%x uid=%d gid=%d size=%lld\n"
1893 		"    atime_sec=%lld atime_nsec=%lld\n"
1894 		"    mtime_sec=%lld mtime_nsec=%lld\n",
1895 		p9attr->valid, p9attr->mode,
1896 		from_kuid(&init_user_ns, p9attr->uid),
1897 		from_kgid(&init_user_ns, p9attr->gid),
1898 		p9attr->size, p9attr->atime_sec, p9attr->atime_nsec,
1899 		p9attr->mtime_sec, p9attr->mtime_nsec);
1900 
1901 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1902 
1903 	if (IS_ERR(req)) {
1904 		err = PTR_ERR(req);
1905 		goto error;
1906 	}
1907 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1908 	p9_tag_remove(clnt, req);
1909 error:
1910 	return err;
1911 }
1912 EXPORT_SYMBOL(p9_client_setattr);
1913 
1914 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1915 {
1916 	int err;
1917 	struct p9_req_t *req;
1918 	struct p9_client *clnt;
1919 
1920 	err = 0;
1921 	clnt = fid->clnt;
1922 
1923 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1924 
1925 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1926 	if (IS_ERR(req)) {
1927 		err = PTR_ERR(req);
1928 		goto error;
1929 	}
1930 
1931 	err = p9pdu_readf(&req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1932 			  &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1933 			  &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1934 	if (err) {
1935 		trace_9p_protocol_dump(clnt, &req->rc);
1936 		p9_tag_remove(clnt, req);
1937 		goto error;
1938 	}
1939 
1940 	p9_debug(P9_DEBUG_9P, "<<< RSTATFS fid %d type 0x%lx bsize %ld "
1941 		"blocks %llu bfree %llu bavail %llu files %llu ffree %llu "
1942 		"fsid %llu namelen %ld\n",
1943 		fid->fid, (long unsigned int)sb->type, (long int)sb->bsize,
1944 		sb->blocks, sb->bfree, sb->bavail, sb->files,  sb->ffree,
1945 		sb->fsid, (long int)sb->namelen);
1946 
1947 	p9_tag_remove(clnt, req);
1948 error:
1949 	return err;
1950 }
1951 EXPORT_SYMBOL(p9_client_statfs);
1952 
1953 int p9_client_rename(struct p9_fid *fid,
1954 		     struct p9_fid *newdirfid, const char *name)
1955 {
1956 	int err;
1957 	struct p9_req_t *req;
1958 	struct p9_client *clnt;
1959 
1960 	err = 0;
1961 	clnt = fid->clnt;
1962 
1963 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1964 			fid->fid, newdirfid->fid, name);
1965 
1966 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1967 			newdirfid->fid, name);
1968 	if (IS_ERR(req)) {
1969 		err = PTR_ERR(req);
1970 		goto error;
1971 	}
1972 
1973 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1974 
1975 	p9_tag_remove(clnt, req);
1976 error:
1977 	return err;
1978 }
1979 EXPORT_SYMBOL(p9_client_rename);
1980 
1981 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
1982 		       struct p9_fid *newdirfid, const char *new_name)
1983 {
1984 	int err;
1985 	struct p9_req_t *req;
1986 	struct p9_client *clnt;
1987 
1988 	err = 0;
1989 	clnt = olddirfid->clnt;
1990 
1991 	p9_debug(P9_DEBUG_9P, ">>> TRENAMEAT olddirfid %d old name %s"
1992 		   " newdirfid %d new name %s\n", olddirfid->fid, old_name,
1993 		   newdirfid->fid, new_name);
1994 
1995 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
1996 			    old_name, newdirfid->fid, new_name);
1997 	if (IS_ERR(req)) {
1998 		err = PTR_ERR(req);
1999 		goto error;
2000 	}
2001 
2002 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
2003 		   newdirfid->fid, new_name);
2004 
2005 	p9_tag_remove(clnt, req);
2006 error:
2007 	return err;
2008 }
2009 EXPORT_SYMBOL(p9_client_renameat);
2010 
2011 /*
2012  * An xattrwalk without @attr_name gives the fid for the lisxattr namespace
2013  */
2014 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
2015 				const char *attr_name, u64 *attr_size)
2016 {
2017 	int err;
2018 	struct p9_req_t *req;
2019 	struct p9_client *clnt;
2020 	struct p9_fid *attr_fid;
2021 
2022 	err = 0;
2023 	clnt = file_fid->clnt;
2024 	attr_fid = p9_fid_create(clnt);
2025 	if (!attr_fid) {
2026 		err = -ENOMEM;
2027 		goto error;
2028 	}
2029 	p9_debug(P9_DEBUG_9P,
2030 		">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
2031 		file_fid->fid, attr_fid->fid, attr_name);
2032 
2033 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
2034 			file_fid->fid, attr_fid->fid, attr_name);
2035 	if (IS_ERR(req)) {
2036 		err = PTR_ERR(req);
2037 		goto error;
2038 	}
2039 	err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
2040 	if (err) {
2041 		trace_9p_protocol_dump(clnt, &req->rc);
2042 		p9_tag_remove(clnt, req);
2043 		goto clunk_fid;
2044 	}
2045 	p9_tag_remove(clnt, req);
2046 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
2047 		attr_fid->fid, *attr_size);
2048 	return attr_fid;
2049 clunk_fid:
2050 	p9_client_clunk(attr_fid);
2051 	attr_fid = NULL;
2052 error:
2053 	if (attr_fid && (attr_fid != file_fid))
2054 		p9_fid_destroy(attr_fid);
2055 
2056 	return ERR_PTR(err);
2057 }
2058 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
2059 
2060 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
2061 			u64 attr_size, int flags)
2062 {
2063 	int err;
2064 	struct p9_req_t *req;
2065 	struct p9_client *clnt;
2066 
2067 	p9_debug(P9_DEBUG_9P,
2068 		">>> TXATTRCREATE fid %d name  %s size %lld flag %d\n",
2069 		fid->fid, name, (long long)attr_size, flags);
2070 	err = 0;
2071 	clnt = fid->clnt;
2072 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
2073 			fid->fid, name, attr_size, flags);
2074 	if (IS_ERR(req)) {
2075 		err = PTR_ERR(req);
2076 		goto error;
2077 	}
2078 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
2079 	p9_tag_remove(clnt, req);
2080 error:
2081 	return err;
2082 }
2083 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
2084 
2085 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
2086 {
2087 	int err, rsize, non_zc = 0;
2088 	struct p9_client *clnt;
2089 	struct p9_req_t *req;
2090 	char *dataptr;
2091 	struct kvec kv = {.iov_base = data, .iov_len = count};
2092 	struct iov_iter to;
2093 
2094 	iov_iter_kvec(&to, READ, &kv, 1, count);
2095 
2096 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
2097 				fid->fid, (unsigned long long) offset, count);
2098 
2099 	err = 0;
2100 	clnt = fid->clnt;
2101 
2102 	rsize = fid->iounit;
2103 	if (!rsize || rsize > clnt->msize-P9_READDIRHDRSZ)
2104 		rsize = clnt->msize - P9_READDIRHDRSZ;
2105 
2106 	if (count < rsize)
2107 		rsize = count;
2108 
2109 	/* Don't bother zerocopy for small IO (< 1024) */
2110 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2111 		/*
2112 		 * response header len is 11
2113 		 * PDU Header(7) + IO Size (4)
2114 		 */
2115 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2116 				       11, "dqd", fid->fid, offset, rsize);
2117 	} else {
2118 		non_zc = 1;
2119 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2120 				    offset, rsize);
2121 	}
2122 	if (IS_ERR(req)) {
2123 		err = PTR_ERR(req);
2124 		goto error;
2125 	}
2126 
2127 	err = p9pdu_readf(&req->rc, clnt->proto_version, "D", &count, &dataptr);
2128 	if (err) {
2129 		trace_9p_protocol_dump(clnt, &req->rc);
2130 		goto free_and_error;
2131 	}
2132 	if (rsize < count) {
2133 		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
2134 		count = rsize;
2135 	}
2136 
2137 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
2138 
2139 	if (non_zc)
2140 		memmove(data, dataptr, count);
2141 
2142 	p9_tag_remove(clnt, req);
2143 	return count;
2144 
2145 free_and_error:
2146 	p9_tag_remove(clnt, req);
2147 error:
2148 	return err;
2149 }
2150 EXPORT_SYMBOL(p9_client_readdir);
2151 
2152 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2153 			dev_t rdev, kgid_t gid, struct p9_qid *qid)
2154 {
2155 	int err;
2156 	struct p9_client *clnt;
2157 	struct p9_req_t *req;
2158 
2159 	err = 0;
2160 	clnt = fid->clnt;
2161 	p9_debug(P9_DEBUG_9P, ">>> TMKNOD fid %d name %s mode %d major %d "
2162 		"minor %d\n", fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2163 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2164 		MAJOR(rdev), MINOR(rdev), gid);
2165 	if (IS_ERR(req))
2166 		return PTR_ERR(req);
2167 
2168 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2169 	if (err) {
2170 		trace_9p_protocol_dump(clnt, &req->rc);
2171 		goto error;
2172 	}
2173 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n", qid->type,
2174 				(unsigned long long)qid->path, qid->version);
2175 
2176 error:
2177 	p9_tag_remove(clnt, req);
2178 	return err;
2179 
2180 }
2181 EXPORT_SYMBOL(p9_client_mknod_dotl);
2182 
2183 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2184 				kgid_t gid, struct p9_qid *qid)
2185 {
2186 	int err;
2187 	struct p9_client *clnt;
2188 	struct p9_req_t *req;
2189 
2190 	err = 0;
2191 	clnt = fid->clnt;
2192 	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
2193 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
2194 	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg", fid->fid, name, mode,
2195 		gid);
2196 	if (IS_ERR(req))
2197 		return PTR_ERR(req);
2198 
2199 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2200 	if (err) {
2201 		trace_9p_protocol_dump(clnt, &req->rc);
2202 		goto error;
2203 	}
2204 	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
2205 				(unsigned long long)qid->path, qid->version);
2206 
2207 error:
2208 	p9_tag_remove(clnt, req);
2209 	return err;
2210 
2211 }
2212 EXPORT_SYMBOL(p9_client_mkdir_dotl);
2213 
2214 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
2215 {
2216 	int err;
2217 	struct p9_client *clnt;
2218 	struct p9_req_t *req;
2219 
2220 	err = 0;
2221 	clnt = fid->clnt;
2222 	p9_debug(P9_DEBUG_9P, ">>> TLOCK fid %d type %i flags %d "
2223 			"start %lld length %lld proc_id %d client_id %s\n",
2224 			fid->fid, flock->type, flock->flags, flock->start,
2225 			flock->length, flock->proc_id, flock->client_id);
2226 
2227 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2228 				flock->flags, flock->start, flock->length,
2229 					flock->proc_id, flock->client_id);
2230 
2231 	if (IS_ERR(req))
2232 		return PTR_ERR(req);
2233 
2234 	err = p9pdu_readf(&req->rc, clnt->proto_version, "b", status);
2235 	if (err) {
2236 		trace_9p_protocol_dump(clnt, &req->rc);
2237 		goto error;
2238 	}
2239 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2240 error:
2241 	p9_tag_remove(clnt, req);
2242 	return err;
2243 
2244 }
2245 EXPORT_SYMBOL(p9_client_lock_dotl);
2246 
2247 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2248 {
2249 	int err;
2250 	struct p9_client *clnt;
2251 	struct p9_req_t *req;
2252 
2253 	err = 0;
2254 	clnt = fid->clnt;
2255 	p9_debug(P9_DEBUG_9P, ">>> TGETLOCK fid %d, type %i start %lld "
2256 		"length %lld proc_id %d client_id %s\n", fid->fid, glock->type,
2257 		glock->start, glock->length, glock->proc_id, glock->client_id);
2258 
2259 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,  glock->type,
2260 		glock->start, glock->length, glock->proc_id, glock->client_id);
2261 
2262 	if (IS_ERR(req))
2263 		return PTR_ERR(req);
2264 
2265 	err = p9pdu_readf(&req->rc, clnt->proto_version, "bqqds", &glock->type,
2266 			  &glock->start, &glock->length, &glock->proc_id,
2267 			  &glock->client_id);
2268 	if (err) {
2269 		trace_9p_protocol_dump(clnt, &req->rc);
2270 		goto error;
2271 	}
2272 	p9_debug(P9_DEBUG_9P, "<<< RGETLOCK type %i start %lld length %lld "
2273 		"proc_id %d client_id %s\n", glock->type, glock->start,
2274 		glock->length, glock->proc_id, glock->client_id);
2275 error:
2276 	p9_tag_remove(clnt, req);
2277 	return err;
2278 }
2279 EXPORT_SYMBOL(p9_client_getlock_dotl);
2280 
2281 int p9_client_readlink(struct p9_fid *fid, char **target)
2282 {
2283 	int err;
2284 	struct p9_client *clnt;
2285 	struct p9_req_t *req;
2286 
2287 	err = 0;
2288 	clnt = fid->clnt;
2289 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2290 
2291 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2292 	if (IS_ERR(req))
2293 		return PTR_ERR(req);
2294 
2295 	err = p9pdu_readf(&req->rc, clnt->proto_version, "s", target);
2296 	if (err) {
2297 		trace_9p_protocol_dump(clnt, &req->rc);
2298 		goto error;
2299 	}
2300 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2301 error:
2302 	p9_tag_remove(clnt, req);
2303 	return err;
2304 }
2305 EXPORT_SYMBOL(p9_client_readlink);
2306 
2307 int __init p9_client_init(void)
2308 {
2309 	p9_req_cache = KMEM_CACHE(p9_req_t, SLAB_TYPESAFE_BY_RCU);
2310 	return p9_req_cache ? 0 : -ENOMEM;
2311 }
2312 
2313 void __exit p9_client_exit(void)
2314 {
2315 	kmem_cache_destroy(p9_req_cache);
2316 }
2317