xref: /openbmc/linux/net/9p/client.c (revision 0ad53fe3)
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 #define DEFAULT_MSIZE (128 * 1024)
34 
35 /*
36   * Client Option Parsing (code inspired by NFS code)
37   *  - a little lazy - parse all client options
38   */
39 
40 enum {
41 	Opt_msize,
42 	Opt_trans,
43 	Opt_legacy,
44 	Opt_version,
45 	Opt_err,
46 };
47 
48 static const match_table_t tokens = {
49 	{Opt_msize, "msize=%u"},
50 	{Opt_legacy, "noextend"},
51 	{Opt_trans, "trans=%s"},
52 	{Opt_version, "version=%s"},
53 	{Opt_err, NULL},
54 };
55 
56 inline int p9_is_proto_dotl(struct p9_client *clnt)
57 {
58 	return clnt->proto_version == p9_proto_2000L;
59 }
60 EXPORT_SYMBOL(p9_is_proto_dotl);
61 
62 inline int p9_is_proto_dotu(struct p9_client *clnt)
63 {
64 	return clnt->proto_version == p9_proto_2000u;
65 }
66 EXPORT_SYMBOL(p9_is_proto_dotu);
67 
68 int p9_show_client_options(struct seq_file *m, struct p9_client *clnt)
69 {
70 	if (clnt->msize != DEFAULT_MSIZE)
71 		seq_printf(m, ",msize=%u", clnt->msize);
72 	seq_printf(m, ",trans=%s", clnt->trans_mod->name);
73 
74 	switch (clnt->proto_version) {
75 	case p9_proto_legacy:
76 		seq_puts(m, ",noextend");
77 		break;
78 	case p9_proto_2000u:
79 		seq_puts(m, ",version=9p2000.u");
80 		break;
81 	case p9_proto_2000L:
82 		/* Default */
83 		break;
84 	}
85 
86 	if (clnt->trans_mod->show_options)
87 		return clnt->trans_mod->show_options(m, clnt);
88 	return 0;
89 }
90 EXPORT_SYMBOL(p9_show_client_options);
91 
92 /*
93  * Some error codes are taken directly from the server replies,
94  * make sure they are valid.
95  */
96 static int safe_errno(int err)
97 {
98 	if ((err > 0) || (err < -MAX_ERRNO)) {
99 		p9_debug(P9_DEBUG_ERROR, "Invalid error code %d\n", err);
100 		return -EPROTO;
101 	}
102 	return err;
103 }
104 
105 
106 /* Interpret mount option for protocol version */
107 static int get_protocol_version(char *s)
108 {
109 	int version = -EINVAL;
110 
111 	if (!strcmp(s, "9p2000")) {
112 		version = p9_proto_legacy;
113 		p9_debug(P9_DEBUG_9P, "Protocol version: Legacy\n");
114 	} else if (!strcmp(s, "9p2000.u")) {
115 		version = p9_proto_2000u;
116 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.u\n");
117 	} else if (!strcmp(s, "9p2000.L")) {
118 		version = p9_proto_2000L;
119 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.L\n");
120 	} else
121 		pr_info("Unknown protocol version %s\n", s);
122 
123 	return version;
124 }
125 
126 /**
127  * parse_opts - parse mount options into client structure
128  * @opts: options string passed from mount
129  * @clnt: existing v9fs client information
130  *
131  * Return 0 upon success, -ERRNO upon failure
132  */
133 
134 static int parse_opts(char *opts, struct p9_client *clnt)
135 {
136 	char *options, *tmp_options;
137 	char *p;
138 	substring_t args[MAX_OPT_ARGS];
139 	int option;
140 	char *s;
141 	int ret = 0;
142 
143 	clnt->proto_version = p9_proto_2000L;
144 	clnt->msize = DEFAULT_MSIZE;
145 
146 	if (!opts)
147 		return 0;
148 
149 	tmp_options = kstrdup(opts, GFP_KERNEL);
150 	if (!tmp_options) {
151 		p9_debug(P9_DEBUG_ERROR,
152 			 "failed to allocate copy of option string\n");
153 		return -ENOMEM;
154 	}
155 	options = tmp_options;
156 
157 	while ((p = strsep(&options, ",")) != NULL) {
158 		int token, r;
159 		if (!*p)
160 			continue;
161 		token = match_token(p, tokens, args);
162 		switch (token) {
163 		case Opt_msize:
164 			r = match_int(&args[0], &option);
165 			if (r < 0) {
166 				p9_debug(P9_DEBUG_ERROR,
167 					 "integer field, but no integer?\n");
168 				ret = r;
169 				continue;
170 			}
171 			if (option < 4096) {
172 				p9_debug(P9_DEBUG_ERROR,
173 					 "msize should be at least 4k\n");
174 				ret = -EINVAL;
175 				continue;
176 			}
177 			clnt->msize = option;
178 			break;
179 		case Opt_trans:
180 			s = match_strdup(&args[0]);
181 			if (!s) {
182 				ret = -ENOMEM;
183 				p9_debug(P9_DEBUG_ERROR,
184 					 "problem allocating copy of trans arg\n");
185 				goto free_and_return;
186 			}
187 
188 			v9fs_put_trans(clnt->trans_mod);
189 			clnt->trans_mod = v9fs_get_trans_by_name(s);
190 			if (clnt->trans_mod == NULL) {
191 				pr_info("Could not find request transport: %s\n",
192 					s);
193 				ret = -EINVAL;
194 			}
195 			kfree(s);
196 			break;
197 		case Opt_legacy:
198 			clnt->proto_version = p9_proto_legacy;
199 			break;
200 		case Opt_version:
201 			s = match_strdup(&args[0]);
202 			if (!s) {
203 				ret = -ENOMEM;
204 				p9_debug(P9_DEBUG_ERROR,
205 					 "problem allocating copy of version arg\n");
206 				goto free_and_return;
207 			}
208 			r = get_protocol_version(s);
209 			if (r < 0)
210 				ret = r;
211 			else
212 				clnt->proto_version = r;
213 			kfree(s);
214 			break;
215 		default:
216 			continue;
217 		}
218 	}
219 
220 free_and_return:
221 	if (ret)
222 		v9fs_put_trans(clnt->trans_mod);
223 	kfree(tmp_options);
224 	return ret;
225 }
226 
227 static int p9_fcall_init(struct p9_client *c, struct p9_fcall *fc,
228 			 int alloc_msize)
229 {
230 	if (likely(c->fcall_cache) && alloc_msize == c->msize) {
231 		fc->sdata = kmem_cache_alloc(c->fcall_cache, GFP_NOFS);
232 		fc->cache = c->fcall_cache;
233 	} else {
234 		fc->sdata = kmalloc(alloc_msize, GFP_NOFS);
235 		fc->cache = NULL;
236 	}
237 	if (!fc->sdata)
238 		return -ENOMEM;
239 	fc->capacity = alloc_msize;
240 	return 0;
241 }
242 
243 void p9_fcall_fini(struct p9_fcall *fc)
244 {
245 	/* sdata can be NULL for interrupted requests in trans_rdma,
246 	 * and kmem_cache_free does not do NULL-check for us
247 	 */
248 	if (unlikely(!fc->sdata))
249 		return;
250 
251 	if (fc->cache)
252 		kmem_cache_free(fc->cache, fc->sdata);
253 	else
254 		kfree(fc->sdata);
255 }
256 EXPORT_SYMBOL(p9_fcall_fini);
257 
258 static struct kmem_cache *p9_req_cache;
259 
260 /**
261  * p9_tag_alloc - Allocate a new request.
262  * @c: Client session.
263  * @type: Transaction type.
264  * @max_size: Maximum packet size for this request.
265  *
266  * Context: Process context.
267  * Return: Pointer to new request.
268  */
269 static struct p9_req_t *
270 p9_tag_alloc(struct p9_client *c, int8_t type, unsigned int max_size)
271 {
272 	struct p9_req_t *req = kmem_cache_alloc(p9_req_cache, GFP_NOFS);
273 	int alloc_msize = min(c->msize, max_size);
274 	int tag;
275 
276 	if (!req)
277 		return ERR_PTR(-ENOMEM);
278 
279 	if (p9_fcall_init(c, &req->tc, alloc_msize))
280 		goto free_req;
281 	if (p9_fcall_init(c, &req->rc, alloc_msize))
282 		goto free;
283 
284 	p9pdu_reset(&req->tc);
285 	p9pdu_reset(&req->rc);
286 	req->t_err = 0;
287 	req->status = REQ_STATUS_ALLOC;
288 	init_waitqueue_head(&req->wq);
289 	INIT_LIST_HEAD(&req->req_list);
290 
291 	idr_preload(GFP_NOFS);
292 	spin_lock_irq(&c->lock);
293 	if (type == P9_TVERSION)
294 		tag = idr_alloc(&c->reqs, req, P9_NOTAG, P9_NOTAG + 1,
295 				GFP_NOWAIT);
296 	else
297 		tag = idr_alloc(&c->reqs, req, 0, P9_NOTAG, GFP_NOWAIT);
298 	req->tc.tag = tag;
299 	spin_unlock_irq(&c->lock);
300 	idr_preload_end();
301 	if (tag < 0)
302 		goto free;
303 
304 	/* Init ref to two because in the general case there is one ref
305 	 * that is put asynchronously by a writer thread, one ref
306 	 * temporarily given by p9_tag_lookup and put by p9_client_cb
307 	 * in the recv thread, and one ref put by p9_tag_remove in the
308 	 * main thread. The only exception is virtio that does not use
309 	 * p9_tag_lookup but does not have a writer thread either
310 	 * (the write happens synchronously in the request/zc_request
311 	 * callback), so p9_client_cb eats the second ref there
312 	 * as the pointer is duplicated directly by virtqueue_add_sgs()
313 	 */
314 	refcount_set(&req->refcount.refcount, 2);
315 
316 	return req;
317 
318 free:
319 	p9_fcall_fini(&req->tc);
320 	p9_fcall_fini(&req->rc);
321 free_req:
322 	kmem_cache_free(p9_req_cache, req);
323 	return ERR_PTR(-ENOMEM);
324 }
325 
326 /**
327  * p9_tag_lookup - Look up a request by tag.
328  * @c: Client session.
329  * @tag: Transaction ID.
330  *
331  * Context: Any context.
332  * Return: A request, or %NULL if there is no request with that tag.
333  */
334 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
335 {
336 	struct p9_req_t *req;
337 
338 	rcu_read_lock();
339 again:
340 	req = idr_find(&c->reqs, tag);
341 	if (req) {
342 		/* We have to be careful with the req found under rcu_read_lock
343 		 * Thanks to SLAB_TYPESAFE_BY_RCU we can safely try to get the
344 		 * ref again without corrupting other data, then check again
345 		 * that the tag matches once we have the ref
346 		 */
347 		if (!p9_req_try_get(req))
348 			goto again;
349 		if (req->tc.tag != tag) {
350 			p9_req_put(req);
351 			goto again;
352 		}
353 	}
354 	rcu_read_unlock();
355 
356 	return req;
357 }
358 EXPORT_SYMBOL(p9_tag_lookup);
359 
360 /**
361  * p9_tag_remove - Remove a tag.
362  * @c: Client session.
363  * @r: Request of reference.
364  *
365  * Context: Any context.
366  */
367 static int p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
368 {
369 	unsigned long flags;
370 	u16 tag = r->tc.tag;
371 
372 	p9_debug(P9_DEBUG_MUX, "clnt %p req %p tag: %d\n", c, r, tag);
373 	spin_lock_irqsave(&c->lock, flags);
374 	idr_remove(&c->reqs, tag);
375 	spin_unlock_irqrestore(&c->lock, flags);
376 	return p9_req_put(r);
377 }
378 
379 static void p9_req_free(struct kref *ref)
380 {
381 	struct p9_req_t *r = container_of(ref, struct p9_req_t, refcount);
382 	p9_fcall_fini(&r->tc);
383 	p9_fcall_fini(&r->rc);
384 	kmem_cache_free(p9_req_cache, r);
385 }
386 
387 int p9_req_put(struct p9_req_t *r)
388 {
389 	return kref_put(&r->refcount, p9_req_free);
390 }
391 EXPORT_SYMBOL(p9_req_put);
392 
393 /**
394  * p9_tag_cleanup - cleans up tags structure and reclaims resources
395  * @c:  v9fs client struct
396  *
397  * This frees resources associated with the tags structure
398  *
399  */
400 static void p9_tag_cleanup(struct p9_client *c)
401 {
402 	struct p9_req_t *req;
403 	int id;
404 
405 	rcu_read_lock();
406 	idr_for_each_entry(&c->reqs, req, id) {
407 		pr_info("Tag %d still in use\n", id);
408 		if (p9_tag_remove(c, req) == 0)
409 			pr_warn("Packet with tag %d has still references",
410 				req->tc.tag);
411 	}
412 	rcu_read_unlock();
413 }
414 
415 /**
416  * p9_client_cb - call back from transport to client
417  * @c: client state
418  * @req: request received
419  * @status: request status, one of REQ_STATUS_*
420  *
421  */
422 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
423 {
424 	p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc.tag);
425 
426 	/*
427 	 * This barrier is needed to make sure any change made to req before
428 	 * the status change is visible to another thread
429 	 */
430 	smp_wmb();
431 	req->status = status;
432 
433 	wake_up(&req->wq);
434 	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
435 	p9_req_put(req);
436 }
437 EXPORT_SYMBOL(p9_client_cb);
438 
439 /**
440  * p9_parse_header - parse header arguments out of a packet
441  * @pdu: packet to parse
442  * @size: size of packet
443  * @type: type of request
444  * @tag: tag of packet
445  * @rewind: set if we need to rewind offset afterwards
446  */
447 
448 int
449 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type, int16_t *tag,
450 								int rewind)
451 {
452 	int8_t r_type;
453 	int16_t r_tag;
454 	int32_t r_size;
455 	int offset = pdu->offset;
456 	int err;
457 
458 	pdu->offset = 0;
459 
460 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
461 	if (err)
462 		goto rewind_and_exit;
463 
464 	if (type)
465 		*type = r_type;
466 	if (tag)
467 		*tag = r_tag;
468 	if (size)
469 		*size = r_size;
470 
471 	if (pdu->size != r_size || r_size < 7) {
472 		err = -EINVAL;
473 		goto rewind_and_exit;
474 	}
475 
476 	pdu->id = r_type;
477 	pdu->tag = r_tag;
478 
479 	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
480 		 pdu->size, pdu->id, pdu->tag);
481 
482 rewind_and_exit:
483 	if (rewind)
484 		pdu->offset = offset;
485 	return err;
486 }
487 EXPORT_SYMBOL(p9_parse_header);
488 
489 /**
490  * p9_check_errors - check 9p packet for error return and process it
491  * @c: current client instance
492  * @req: request to parse and check for error conditions
493  *
494  * returns error code if one is discovered, otherwise returns 0
495  *
496  * this will have to be more complicated if we have multiple
497  * error packet types
498  */
499 
500 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
501 {
502 	int8_t type;
503 	int err;
504 	int ecode;
505 
506 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
507 	if (req->rc.size >= c->msize) {
508 		p9_debug(P9_DEBUG_ERROR,
509 			 "requested packet size too big: %d\n",
510 			 req->rc.size);
511 		return -EIO;
512 	}
513 	/*
514 	 * dump the response from server
515 	 * This should be after check errors which poplulate pdu_fcall.
516 	 */
517 	trace_9p_protocol_dump(c, &req->rc);
518 	if (err) {
519 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
520 		return err;
521 	}
522 	if (type != P9_RERROR && type != P9_RLERROR)
523 		return 0;
524 
525 	if (!p9_is_proto_dotl(c)) {
526 		char *ename;
527 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
528 				  &ename, &ecode);
529 		if (err)
530 			goto out_err;
531 
532 		if (p9_is_proto_dotu(c) && ecode < 512)
533 			err = -ecode;
534 
535 		if (!err) {
536 			err = p9_errstr2errno(ename, strlen(ename));
537 
538 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
539 				 -ecode, ename);
540 		}
541 		kfree(ename);
542 	} else {
543 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
544 		err = -ecode;
545 
546 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
547 	}
548 
549 	return err;
550 
551 out_err:
552 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
553 
554 	return err;
555 }
556 
557 /**
558  * p9_check_zc_errors - check 9p packet for error return and process it
559  * @c: current client instance
560  * @req: request to parse and check for error conditions
561  * @uidata: external buffer containing error
562  * @in_hdrlen: Size of response protocol buffer.
563  *
564  * returns error code if one is discovered, otherwise returns 0
565  *
566  * this will have to be more complicated if we have multiple
567  * error packet types
568  */
569 
570 static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
571 			      struct iov_iter *uidata, int in_hdrlen)
572 {
573 	int err;
574 	int ecode;
575 	int8_t type;
576 	char *ename = NULL;
577 
578 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
579 	/*
580 	 * dump the response from server
581 	 * This should be after parse_header which poplulate pdu_fcall.
582 	 */
583 	trace_9p_protocol_dump(c, &req->rc);
584 	if (err) {
585 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
586 		return err;
587 	}
588 
589 	if (type != P9_RERROR && type != P9_RLERROR)
590 		return 0;
591 
592 	if (!p9_is_proto_dotl(c)) {
593 		/* Error is reported in string format */
594 		int len;
595 		/* 7 = header size for RERROR; */
596 		int inline_len = in_hdrlen - 7;
597 
598 		len = req->rc.size - req->rc.offset;
599 		if (len > (P9_ZC_HDR_SZ - 7)) {
600 			err = -EFAULT;
601 			goto out_err;
602 		}
603 
604 		ename = &req->rc.sdata[req->rc.offset];
605 		if (len > inline_len) {
606 			/* We have error in external buffer */
607 			if (!copy_from_iter_full(ename + inline_len,
608 					     len - inline_len, uidata)) {
609 				err = -EFAULT;
610 				goto out_err;
611 			}
612 		}
613 		ename = NULL;
614 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
615 				  &ename, &ecode);
616 		if (err)
617 			goto out_err;
618 
619 		if (p9_is_proto_dotu(c) && ecode < 512)
620 			err = -ecode;
621 
622 		if (!err) {
623 			err = p9_errstr2errno(ename, strlen(ename));
624 
625 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
626 				 -ecode, ename);
627 		}
628 		kfree(ename);
629 	} else {
630 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
631 		err = -ecode;
632 
633 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
634 	}
635 	return err;
636 
637 out_err:
638 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
639 	return err;
640 }
641 
642 static struct p9_req_t *
643 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
644 
645 /**
646  * p9_client_flush - flush (cancel) a request
647  * @c: client state
648  * @oldreq: request to cancel
649  *
650  * This sents a flush for a particular request and links
651  * the flush request to the original request.  The current
652  * code only supports a single flush request although the protocol
653  * allows for multiple flush requests to be sent for a single request.
654  *
655  */
656 
657 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
658 {
659 	struct p9_req_t *req;
660 	int16_t oldtag;
661 	int err;
662 
663 	err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
664 	if (err)
665 		return err;
666 
667 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
668 
669 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
670 	if (IS_ERR(req))
671 		return PTR_ERR(req);
672 
673 	/*
674 	 * if we haven't received a response for oldreq,
675 	 * remove it from the list
676 	 */
677 	if (oldreq->status == REQ_STATUS_SENT) {
678 		if (c->trans_mod->cancelled)
679 			c->trans_mod->cancelled(c, oldreq);
680 	}
681 
682 	p9_tag_remove(c, req);
683 	return 0;
684 }
685 
686 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
687 					      int8_t type, int req_size,
688 					      const char *fmt, va_list ap)
689 {
690 	int err;
691 	struct p9_req_t *req;
692 
693 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
694 
695 	/* we allow for any status other than disconnected */
696 	if (c->status == Disconnected)
697 		return ERR_PTR(-EIO);
698 
699 	/* if status is begin_disconnected we allow only clunk request */
700 	if ((c->status == BeginDisconnect) && (type != P9_TCLUNK))
701 		return ERR_PTR(-EIO);
702 
703 	req = p9_tag_alloc(c, type, req_size);
704 	if (IS_ERR(req))
705 		return req;
706 
707 	/* marshall the data */
708 	p9pdu_prepare(&req->tc, req->tc.tag, type);
709 	err = p9pdu_vwritef(&req->tc, c->proto_version, fmt, ap);
710 	if (err)
711 		goto reterr;
712 	p9pdu_finalize(c, &req->tc);
713 	trace_9p_client_req(c, type, req->tc.tag);
714 	return req;
715 reterr:
716 	p9_tag_remove(c, req);
717 	/* We have to put also the 2nd reference as it won't be used */
718 	p9_req_put(req);
719 	return ERR_PTR(err);
720 }
721 
722 /**
723  * p9_client_rpc - issue a request and wait for a response
724  * @c: client session
725  * @type: type of request
726  * @fmt: protocol format string (see protocol.c)
727  *
728  * Returns request structure (which client must free using p9_tag_remove)
729  */
730 
731 static struct p9_req_t *
732 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
733 {
734 	va_list ap;
735 	int sigpending, err;
736 	unsigned long flags;
737 	struct p9_req_t *req;
738 
739 	va_start(ap, fmt);
740 	req = p9_client_prepare_req(c, type, c->msize, fmt, ap);
741 	va_end(ap);
742 	if (IS_ERR(req))
743 		return req;
744 
745 	if (signal_pending(current)) {
746 		sigpending = 1;
747 		clear_thread_flag(TIF_SIGPENDING);
748 	} else
749 		sigpending = 0;
750 
751 	err = c->trans_mod->request(c, req);
752 	if (err < 0) {
753 		/* write won't happen */
754 		p9_req_put(req);
755 		if (err != -ERESTARTSYS && err != -EFAULT)
756 			c->status = Disconnected;
757 		goto recalc_sigpending;
758 	}
759 again:
760 	/* Wait for the response */
761 	err = wait_event_killable(req->wq, req->status >= REQ_STATUS_RCVD);
762 
763 	/*
764 	 * Make sure our req is coherent with regard to updates in other
765 	 * threads - echoes to wmb() in the callback
766 	 */
767 	smp_rmb();
768 
769 	if ((err == -ERESTARTSYS) && (c->status == Connected)
770 				  && (type == P9_TFLUSH)) {
771 		sigpending = 1;
772 		clear_thread_flag(TIF_SIGPENDING);
773 		goto again;
774 	}
775 
776 	if (req->status == REQ_STATUS_ERROR) {
777 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
778 		err = req->t_err;
779 	}
780 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
781 		p9_debug(P9_DEBUG_MUX, "flushing\n");
782 		sigpending = 1;
783 		clear_thread_flag(TIF_SIGPENDING);
784 
785 		if (c->trans_mod->cancel(c, req))
786 			p9_client_flush(c, req);
787 
788 		/* if we received the response anyway, don't signal error */
789 		if (req->status == REQ_STATUS_RCVD)
790 			err = 0;
791 	}
792 recalc_sigpending:
793 	if (sigpending) {
794 		spin_lock_irqsave(&current->sighand->siglock, flags);
795 		recalc_sigpending();
796 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
797 	}
798 	if (err < 0)
799 		goto reterr;
800 
801 	err = p9_check_errors(c, req);
802 	trace_9p_client_res(c, type, req->rc.tag, err);
803 	if (!err)
804 		return req;
805 reterr:
806 	p9_tag_remove(c, req);
807 	return ERR_PTR(safe_errno(err));
808 }
809 
810 /**
811  * p9_client_zc_rpc - issue a request and wait for a response
812  * @c: client session
813  * @type: type of request
814  * @uidata: destination for zero copy read
815  * @uodata: source for zero copy write
816  * @inlen: read buffer size
817  * @olen: write buffer size
818  * @in_hdrlen: reader header size, This is the size of response protocol data
819  * @fmt: protocol format string (see protocol.c)
820  *
821  * Returns request structure (which client must free using p9_tag_remove)
822  */
823 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
824 					 struct iov_iter *uidata,
825 					 struct iov_iter *uodata,
826 					 int inlen, int olen, int in_hdrlen,
827 					 const char *fmt, ...)
828 {
829 	va_list ap;
830 	int sigpending, err;
831 	unsigned long flags;
832 	struct p9_req_t *req;
833 
834 	va_start(ap, fmt);
835 	/*
836 	 * We allocate a inline protocol data of only 4k bytes.
837 	 * The actual content is passed in zero-copy fashion.
838 	 */
839 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, fmt, ap);
840 	va_end(ap);
841 	if (IS_ERR(req))
842 		return req;
843 
844 	if (signal_pending(current)) {
845 		sigpending = 1;
846 		clear_thread_flag(TIF_SIGPENDING);
847 	} else
848 		sigpending = 0;
849 
850 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
851 				       inlen, olen, in_hdrlen);
852 	if (err < 0) {
853 		if (err == -EIO)
854 			c->status = Disconnected;
855 		if (err != -ERESTARTSYS)
856 			goto recalc_sigpending;
857 	}
858 	if (req->status == REQ_STATUS_ERROR) {
859 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
860 		err = req->t_err;
861 	}
862 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
863 		p9_debug(P9_DEBUG_MUX, "flushing\n");
864 		sigpending = 1;
865 		clear_thread_flag(TIF_SIGPENDING);
866 
867 		if (c->trans_mod->cancel(c, req))
868 			p9_client_flush(c, req);
869 
870 		/* if we received the response anyway, don't signal error */
871 		if (req->status == REQ_STATUS_RCVD)
872 			err = 0;
873 	}
874 recalc_sigpending:
875 	if (sigpending) {
876 		spin_lock_irqsave(&current->sighand->siglock, flags);
877 		recalc_sigpending();
878 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
879 	}
880 	if (err < 0)
881 		goto reterr;
882 
883 	err = p9_check_zc_errors(c, req, uidata, in_hdrlen);
884 	trace_9p_client_res(c, type, req->rc.tag, err);
885 	if (!err)
886 		return req;
887 reterr:
888 	p9_tag_remove(c, req);
889 	return ERR_PTR(safe_errno(err));
890 }
891 
892 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
893 {
894 	int ret;
895 	struct p9_fid *fid;
896 
897 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
898 	fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
899 	if (!fid)
900 		return NULL;
901 
902 	memset(&fid->qid, 0, sizeof(struct p9_qid));
903 	fid->mode = -1;
904 	fid->uid = current_fsuid();
905 	fid->clnt = clnt;
906 	fid->rdir = NULL;
907 	fid->fid = 0;
908 	refcount_set(&fid->count, 1);
909 
910 	idr_preload(GFP_KERNEL);
911 	spin_lock_irq(&clnt->lock);
912 	ret = idr_alloc_u32(&clnt->fids, fid, &fid->fid, P9_NOFID - 1,
913 			    GFP_NOWAIT);
914 	spin_unlock_irq(&clnt->lock);
915 	idr_preload_end();
916 	if (!ret)
917 		return fid;
918 
919 	kfree(fid);
920 	return NULL;
921 }
922 
923 static void p9_fid_destroy(struct p9_fid *fid)
924 {
925 	struct p9_client *clnt;
926 	unsigned long flags;
927 
928 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
929 	clnt = fid->clnt;
930 	spin_lock_irqsave(&clnt->lock, flags);
931 	idr_remove(&clnt->fids, fid->fid);
932 	spin_unlock_irqrestore(&clnt->lock, flags);
933 	kfree(fid->rdir);
934 	kfree(fid);
935 }
936 
937 static int p9_client_version(struct p9_client *c)
938 {
939 	int err = 0;
940 	struct p9_req_t *req;
941 	char *version = NULL;
942 	int msize;
943 
944 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
945 		 c->msize, c->proto_version);
946 
947 	switch (c->proto_version) {
948 	case p9_proto_2000L:
949 		req = p9_client_rpc(c, P9_TVERSION, "ds",
950 					c->msize, "9P2000.L");
951 		break;
952 	case p9_proto_2000u:
953 		req = p9_client_rpc(c, P9_TVERSION, "ds",
954 					c->msize, "9P2000.u");
955 		break;
956 	case p9_proto_legacy:
957 		req = p9_client_rpc(c, P9_TVERSION, "ds",
958 					c->msize, "9P2000");
959 		break;
960 	default:
961 		return -EINVAL;
962 	}
963 
964 	if (IS_ERR(req))
965 		return PTR_ERR(req);
966 
967 	err = p9pdu_readf(&req->rc, c->proto_version, "ds", &msize, &version);
968 	if (err) {
969 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
970 		trace_9p_protocol_dump(c, &req->rc);
971 		goto error;
972 	}
973 
974 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
975 	if (!strncmp(version, "9P2000.L", 8))
976 		c->proto_version = p9_proto_2000L;
977 	else if (!strncmp(version, "9P2000.u", 8))
978 		c->proto_version = p9_proto_2000u;
979 	else if (!strncmp(version, "9P2000", 6))
980 		c->proto_version = p9_proto_legacy;
981 	else {
982 		p9_debug(P9_DEBUG_ERROR,
983 			 "server returned an unknown version: %s\n", version);
984 		err = -EREMOTEIO;
985 		goto error;
986 	}
987 
988 	if (msize < 4096) {
989 		p9_debug(P9_DEBUG_ERROR,
990 			 "server returned a msize < 4096: %d\n", msize);
991 		err = -EREMOTEIO;
992 		goto error;
993 	}
994 	if (msize < c->msize)
995 		c->msize = msize;
996 
997 error:
998 	kfree(version);
999 	p9_tag_remove(c, req);
1000 
1001 	return err;
1002 }
1003 
1004 struct p9_client *p9_client_create(const char *dev_name, char *options)
1005 {
1006 	int err;
1007 	struct p9_client *clnt;
1008 	char *client_id;
1009 
1010 	err = 0;
1011 	clnt = kmalloc(sizeof(struct p9_client), GFP_KERNEL);
1012 	if (!clnt)
1013 		return ERR_PTR(-ENOMEM);
1014 
1015 	clnt->trans_mod = NULL;
1016 	clnt->trans = NULL;
1017 	clnt->fcall_cache = NULL;
1018 
1019 	client_id = utsname()->nodename;
1020 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
1021 
1022 	spin_lock_init(&clnt->lock);
1023 	idr_init(&clnt->fids);
1024 	idr_init(&clnt->reqs);
1025 
1026 	err = parse_opts(options, clnt);
1027 	if (err < 0)
1028 		goto free_client;
1029 
1030 	if (!clnt->trans_mod)
1031 		clnt->trans_mod = v9fs_get_default_trans();
1032 
1033 	if (clnt->trans_mod == NULL) {
1034 		err = -EPROTONOSUPPORT;
1035 		p9_debug(P9_DEBUG_ERROR,
1036 			 "No transport defined or default transport\n");
1037 		goto free_client;
1038 	}
1039 
1040 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
1041 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
1042 
1043 	err = clnt->trans_mod->create(clnt, dev_name, options);
1044 	if (err)
1045 		goto put_trans;
1046 
1047 	if (clnt->msize > clnt->trans_mod->maxsize)
1048 		clnt->msize = clnt->trans_mod->maxsize;
1049 
1050 	if (clnt->msize < 4096) {
1051 		p9_debug(P9_DEBUG_ERROR,
1052 			 "Please specify a msize of at least 4k\n");
1053 		err = -EINVAL;
1054 		goto close_trans;
1055 	}
1056 
1057 	err = p9_client_version(clnt);
1058 	if (err)
1059 		goto close_trans;
1060 
1061 	/* P9_HDRSZ + 4 is the smallest packet header we can have that is
1062 	 * followed by data accessed from userspace by read
1063 	 */
1064 	clnt->fcall_cache =
1065 		kmem_cache_create_usercopy("9p-fcall-cache", clnt->msize,
1066 					   0, 0, P9_HDRSZ + 4,
1067 					   clnt->msize - (P9_HDRSZ + 4),
1068 					   NULL);
1069 
1070 	return clnt;
1071 
1072 close_trans:
1073 	clnt->trans_mod->close(clnt);
1074 put_trans:
1075 	v9fs_put_trans(clnt->trans_mod);
1076 free_client:
1077 	kfree(clnt);
1078 	return ERR_PTR(err);
1079 }
1080 EXPORT_SYMBOL(p9_client_create);
1081 
1082 void p9_client_destroy(struct p9_client *clnt)
1083 {
1084 	struct p9_fid *fid;
1085 	int id;
1086 
1087 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1088 
1089 	if (clnt->trans_mod)
1090 		clnt->trans_mod->close(clnt);
1091 
1092 	v9fs_put_trans(clnt->trans_mod);
1093 
1094 	idr_for_each_entry(&clnt->fids, fid, id) {
1095 		pr_info("Found fid %d not clunked\n", fid->fid);
1096 		p9_fid_destroy(fid);
1097 	}
1098 
1099 	p9_tag_cleanup(clnt);
1100 
1101 	kmem_cache_destroy(clnt->fcall_cache);
1102 	kfree(clnt);
1103 }
1104 EXPORT_SYMBOL(p9_client_destroy);
1105 
1106 void p9_client_disconnect(struct p9_client *clnt)
1107 {
1108 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1109 	clnt->status = Disconnected;
1110 }
1111 EXPORT_SYMBOL(p9_client_disconnect);
1112 
1113 void p9_client_begin_disconnect(struct p9_client *clnt)
1114 {
1115 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1116 	clnt->status = BeginDisconnect;
1117 }
1118 EXPORT_SYMBOL(p9_client_begin_disconnect);
1119 
1120 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1121 	const char *uname, kuid_t n_uname, const char *aname)
1122 {
1123 	int err = 0;
1124 	struct p9_req_t *req;
1125 	struct p9_fid *fid;
1126 	struct p9_qid qid;
1127 
1128 
1129 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1130 		 afid ? afid->fid : -1, uname, aname);
1131 	fid = p9_fid_create(clnt);
1132 	if (!fid) {
1133 		err = -ENOMEM;
1134 		goto error;
1135 	}
1136 	fid->uid = n_uname;
1137 
1138 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
1139 			afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
1140 	if (IS_ERR(req)) {
1141 		err = PTR_ERR(req);
1142 		goto error;
1143 	}
1144 
1145 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", &qid);
1146 	if (err) {
1147 		trace_9p_protocol_dump(clnt, &req->rc);
1148 		p9_tag_remove(clnt, req);
1149 		goto error;
1150 	}
1151 
1152 	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
1153 		 qid.type, (unsigned long long)qid.path, qid.version);
1154 
1155 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1156 
1157 	p9_tag_remove(clnt, req);
1158 	return fid;
1159 
1160 error:
1161 	if (fid)
1162 		p9_fid_destroy(fid);
1163 	return ERR_PTR(err);
1164 }
1165 EXPORT_SYMBOL(p9_client_attach);
1166 
1167 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
1168 		const unsigned char * const *wnames, int clone)
1169 {
1170 	int err;
1171 	struct p9_client *clnt;
1172 	struct p9_fid *fid;
1173 	struct p9_qid *wqids;
1174 	struct p9_req_t *req;
1175 	uint16_t nwqids, count;
1176 
1177 	err = 0;
1178 	wqids = NULL;
1179 	clnt = oldfid->clnt;
1180 	if (clone) {
1181 		fid = p9_fid_create(clnt);
1182 		if (!fid) {
1183 			err = -ENOMEM;
1184 			goto error;
1185 		}
1186 
1187 		fid->uid = oldfid->uid;
1188 	} else
1189 		fid = oldfid;
1190 
1191 
1192 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1193 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1194 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1195 								nwname, wnames);
1196 	if (IS_ERR(req)) {
1197 		err = PTR_ERR(req);
1198 		goto error;
1199 	}
1200 
1201 	err = p9pdu_readf(&req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1202 	if (err) {
1203 		trace_9p_protocol_dump(clnt, &req->rc);
1204 		p9_tag_remove(clnt, req);
1205 		goto clunk_fid;
1206 	}
1207 	p9_tag_remove(clnt, req);
1208 
1209 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1210 
1211 	if (nwqids != nwname) {
1212 		err = -ENOENT;
1213 		goto clunk_fid;
1214 	}
1215 
1216 	for (count = 0; count < nwqids; count++)
1217 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1218 			count, wqids[count].type,
1219 			(unsigned long long)wqids[count].path,
1220 			wqids[count].version);
1221 
1222 	if (nwname)
1223 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1224 	else
1225 		memmove(&fid->qid, &oldfid->qid, sizeof(struct p9_qid));
1226 
1227 	kfree(wqids);
1228 	return fid;
1229 
1230 clunk_fid:
1231 	kfree(wqids);
1232 	p9_client_clunk(fid);
1233 	fid = NULL;
1234 
1235 error:
1236 	if (fid && (fid != oldfid))
1237 		p9_fid_destroy(fid);
1238 
1239 	return ERR_PTR(err);
1240 }
1241 EXPORT_SYMBOL(p9_client_walk);
1242 
1243 int p9_client_open(struct p9_fid *fid, int mode)
1244 {
1245 	int err;
1246 	struct p9_client *clnt;
1247 	struct p9_req_t *req;
1248 	struct p9_qid qid;
1249 	int iounit;
1250 
1251 	clnt = fid->clnt;
1252 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1253 		p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1254 	err = 0;
1255 
1256 	if (fid->mode != -1)
1257 		return -EINVAL;
1258 
1259 	if (p9_is_proto_dotl(clnt))
1260 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode);
1261 	else
1262 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
1263 	if (IS_ERR(req)) {
1264 		err = PTR_ERR(req);
1265 		goto error;
1266 	}
1267 
1268 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1269 	if (err) {
1270 		trace_9p_protocol_dump(clnt, &req->rc);
1271 		goto free_and_error;
1272 	}
1273 
1274 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1275 		p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1276 		(unsigned long long)qid.path, qid.version, iounit);
1277 
1278 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1279 	fid->mode = mode;
1280 	fid->iounit = iounit;
1281 
1282 free_and_error:
1283 	p9_tag_remove(clnt, req);
1284 error:
1285 	return err;
1286 }
1287 EXPORT_SYMBOL(p9_client_open);
1288 
1289 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags, u32 mode,
1290 		kgid_t gid, struct p9_qid *qid)
1291 {
1292 	int err = 0;
1293 	struct p9_client *clnt;
1294 	struct p9_req_t *req;
1295 	int iounit;
1296 
1297 	p9_debug(P9_DEBUG_9P,
1298 			">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1299 			ofid->fid, name, flags, mode,
1300 		 	from_kgid(&init_user_ns, gid));
1301 	clnt = ofid->clnt;
1302 
1303 	if (ofid->mode != -1)
1304 		return -EINVAL;
1305 
1306 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1307 			mode, gid);
1308 	if (IS_ERR(req)) {
1309 		err = PTR_ERR(req);
1310 		goto error;
1311 	}
1312 
1313 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", qid, &iounit);
1314 	if (err) {
1315 		trace_9p_protocol_dump(clnt, &req->rc);
1316 		goto free_and_error;
1317 	}
1318 
1319 	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1320 			qid->type,
1321 			(unsigned long long)qid->path,
1322 			qid->version, iounit);
1323 
1324 	memmove(&ofid->qid, qid, sizeof(struct p9_qid));
1325 	ofid->mode = mode;
1326 	ofid->iounit = iounit;
1327 
1328 free_and_error:
1329 	p9_tag_remove(clnt, req);
1330 error:
1331 	return err;
1332 }
1333 EXPORT_SYMBOL(p9_client_create_dotl);
1334 
1335 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1336 		     char *extension)
1337 {
1338 	int err;
1339 	struct p9_client *clnt;
1340 	struct p9_req_t *req;
1341 	struct p9_qid qid;
1342 	int iounit;
1343 
1344 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1345 						fid->fid, name, perm, mode);
1346 	err = 0;
1347 	clnt = fid->clnt;
1348 
1349 	if (fid->mode != -1)
1350 		return -EINVAL;
1351 
1352 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1353 				mode, extension);
1354 	if (IS_ERR(req)) {
1355 		err = PTR_ERR(req);
1356 		goto error;
1357 	}
1358 
1359 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1360 	if (err) {
1361 		trace_9p_protocol_dump(clnt, &req->rc);
1362 		goto free_and_error;
1363 	}
1364 
1365 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1366 				qid.type,
1367 				(unsigned long long)qid.path,
1368 				qid.version, iounit);
1369 
1370 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1371 	fid->mode = mode;
1372 	fid->iounit = iounit;
1373 
1374 free_and_error:
1375 	p9_tag_remove(clnt, req);
1376 error:
1377 	return err;
1378 }
1379 EXPORT_SYMBOL(p9_client_fcreate);
1380 
1381 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1382 		const char *symtgt, kgid_t gid, struct p9_qid *qid)
1383 {
1384 	int err = 0;
1385 	struct p9_client *clnt;
1386 	struct p9_req_t *req;
1387 
1388 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1389 			dfid->fid, name, symtgt);
1390 	clnt = dfid->clnt;
1391 
1392 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1393 			gid);
1394 	if (IS_ERR(req)) {
1395 		err = PTR_ERR(req);
1396 		goto error;
1397 	}
1398 
1399 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
1400 	if (err) {
1401 		trace_9p_protocol_dump(clnt, &req->rc);
1402 		goto free_and_error;
1403 	}
1404 
1405 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1406 			qid->type, (unsigned long long)qid->path, qid->version);
1407 
1408 free_and_error:
1409 	p9_tag_remove(clnt, req);
1410 error:
1411 	return err;
1412 }
1413 EXPORT_SYMBOL(p9_client_symlink);
1414 
1415 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1416 {
1417 	struct p9_client *clnt;
1418 	struct p9_req_t *req;
1419 
1420 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1421 			dfid->fid, oldfid->fid, newname);
1422 	clnt = dfid->clnt;
1423 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1424 			newname);
1425 	if (IS_ERR(req))
1426 		return PTR_ERR(req);
1427 
1428 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1429 	p9_tag_remove(clnt, req);
1430 	return 0;
1431 }
1432 EXPORT_SYMBOL(p9_client_link);
1433 
1434 int p9_client_fsync(struct p9_fid *fid, int datasync)
1435 {
1436 	int err;
1437 	struct p9_client *clnt;
1438 	struct p9_req_t *req;
1439 
1440 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1441 			fid->fid, datasync);
1442 	err = 0;
1443 	clnt = fid->clnt;
1444 
1445 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1446 	if (IS_ERR(req)) {
1447 		err = PTR_ERR(req);
1448 		goto error;
1449 	}
1450 
1451 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1452 
1453 	p9_tag_remove(clnt, req);
1454 
1455 error:
1456 	return err;
1457 }
1458 EXPORT_SYMBOL(p9_client_fsync);
1459 
1460 int p9_client_clunk(struct p9_fid *fid)
1461 {
1462 	int err;
1463 	struct p9_client *clnt;
1464 	struct p9_req_t *req;
1465 	int retries = 0;
1466 
1467 	if (!fid || IS_ERR(fid)) {
1468 		pr_warn("%s (%d): Trying to clunk with invalid fid\n",
1469 			__func__, task_pid_nr(current));
1470 		dump_stack();
1471 		return 0;
1472 	}
1473 	if (!refcount_dec_and_test(&fid->count))
1474 		return 0;
1475 
1476 again:
1477 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n", fid->fid,
1478 								retries);
1479 	err = 0;
1480 	clnt = fid->clnt;
1481 
1482 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1483 	if (IS_ERR(req)) {
1484 		err = PTR_ERR(req);
1485 		goto error;
1486 	}
1487 
1488 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1489 
1490 	p9_tag_remove(clnt, req);
1491 error:
1492 	/*
1493 	 * Fid is not valid even after a failed clunk
1494 	 * If interrupted, retry once then give up and
1495 	 * leak fid until umount.
1496 	 */
1497 	if (err == -ERESTARTSYS) {
1498 		if (retries++ == 0)
1499 			goto again;
1500 	} else
1501 		p9_fid_destroy(fid);
1502 	return err;
1503 }
1504 EXPORT_SYMBOL(p9_client_clunk);
1505 
1506 int p9_client_remove(struct p9_fid *fid)
1507 {
1508 	int err;
1509 	struct p9_client *clnt;
1510 	struct p9_req_t *req;
1511 
1512 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1513 	err = 0;
1514 	clnt = fid->clnt;
1515 
1516 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1517 	if (IS_ERR(req)) {
1518 		err = PTR_ERR(req);
1519 		goto error;
1520 	}
1521 
1522 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1523 
1524 	p9_tag_remove(clnt, req);
1525 error:
1526 	if (err == -ERESTARTSYS)
1527 		p9_client_clunk(fid);
1528 	else
1529 		p9_fid_destroy(fid);
1530 	return err;
1531 }
1532 EXPORT_SYMBOL(p9_client_remove);
1533 
1534 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1535 {
1536 	int err = 0;
1537 	struct p9_req_t *req;
1538 	struct p9_client *clnt;
1539 
1540 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1541 		   dfid->fid, name, flags);
1542 
1543 	clnt = dfid->clnt;
1544 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1545 	if (IS_ERR(req)) {
1546 		err = PTR_ERR(req);
1547 		goto error;
1548 	}
1549 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1550 
1551 	p9_tag_remove(clnt, req);
1552 error:
1553 	return err;
1554 }
1555 EXPORT_SYMBOL(p9_client_unlinkat);
1556 
1557 int
1558 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1559 {
1560 	int total = 0;
1561 	*err = 0;
1562 
1563 	while (iov_iter_count(to)) {
1564 		int count;
1565 
1566 		count = p9_client_read_once(fid, offset, to, err);
1567 		if (!count || *err)
1568 			break;
1569 		offset += count;
1570 		total += count;
1571 	}
1572 	return total;
1573 }
1574 EXPORT_SYMBOL(p9_client_read);
1575 
1576 int
1577 p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
1578 		    int *err)
1579 {
1580 	struct p9_client *clnt = fid->clnt;
1581 	struct p9_req_t *req;
1582 	int count = iov_iter_count(to);
1583 	int rsize, non_zc = 0;
1584 	char *dataptr;
1585 
1586 	*err = 0;
1587 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n",
1588 		   fid->fid, (unsigned long long) offset, (int)iov_iter_count(to));
1589 
1590 	rsize = fid->iounit;
1591 	if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1592 		rsize = clnt->msize - P9_IOHDRSZ;
1593 
1594 	if (count < rsize)
1595 		rsize = count;
1596 
1597 	/* Don't bother zerocopy for small IO (< 1024) */
1598 	if (clnt->trans_mod->zc_request && rsize > 1024) {
1599 		/* response header len is 11
1600 		 * PDU Header(7) + IO Size (4)
1601 		 */
1602 		req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1603 				       0, 11, "dqd", fid->fid,
1604 				       offset, rsize);
1605 	} else {
1606 		non_zc = 1;
1607 		req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1608 				    rsize);
1609 	}
1610 	if (IS_ERR(req)) {
1611 		*err = PTR_ERR(req);
1612 		return 0;
1613 	}
1614 
1615 	*err = p9pdu_readf(&req->rc, clnt->proto_version,
1616 			   "D", &count, &dataptr);
1617 	if (*err) {
1618 		trace_9p_protocol_dump(clnt, &req->rc);
1619 		p9_tag_remove(clnt, req);
1620 		return 0;
1621 	}
1622 	if (rsize < count) {
1623 		pr_err("bogus RREAD count (%d > %d)\n", count, rsize);
1624 		count = rsize;
1625 	}
1626 
1627 	p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1628 
1629 	if (non_zc) {
1630 		int n = copy_to_iter(dataptr, count, to);
1631 
1632 		if (n != count) {
1633 			*err = -EFAULT;
1634 			p9_tag_remove(clnt, req);
1635 			return n;
1636 		}
1637 	} else {
1638 		iov_iter_advance(to, count);
1639 	}
1640 	p9_tag_remove(clnt, req);
1641 	return count;
1642 }
1643 EXPORT_SYMBOL(p9_client_read_once);
1644 
1645 int
1646 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1647 {
1648 	struct p9_client *clnt = fid->clnt;
1649 	struct p9_req_t *req;
1650 	int total = 0;
1651 	*err = 0;
1652 
1653 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n",
1654 				fid->fid, (unsigned long long) offset,
1655 				iov_iter_count(from));
1656 
1657 	while (iov_iter_count(from)) {
1658 		int count = iov_iter_count(from);
1659 		int rsize = fid->iounit;
1660 		if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1661 			rsize = clnt->msize - P9_IOHDRSZ;
1662 
1663 		if (count < rsize)
1664 			rsize = count;
1665 
1666 		/* Don't bother zerocopy for small IO (< 1024) */
1667 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1668 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1669 					       rsize, P9_ZC_HDR_SZ, "dqd",
1670 					       fid->fid, offset, rsize);
1671 		} else {
1672 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1673 						    offset, rsize, from);
1674 		}
1675 		if (IS_ERR(req)) {
1676 			*err = PTR_ERR(req);
1677 			break;
1678 		}
1679 
1680 		*err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &count);
1681 		if (*err) {
1682 			trace_9p_protocol_dump(clnt, &req->rc);
1683 			p9_tag_remove(clnt, req);
1684 			break;
1685 		}
1686 		if (rsize < count) {
1687 			pr_err("bogus RWRITE count (%d > %d)\n", count, rsize);
1688 			count = rsize;
1689 		}
1690 
1691 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1692 
1693 		p9_tag_remove(clnt, req);
1694 		iov_iter_advance(from, count);
1695 		total += count;
1696 		offset += count;
1697 	}
1698 	return total;
1699 }
1700 EXPORT_SYMBOL(p9_client_write);
1701 
1702 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1703 {
1704 	int err;
1705 	struct p9_client *clnt;
1706 	struct p9_wstat *ret = kmalloc(sizeof(struct p9_wstat), GFP_KERNEL);
1707 	struct p9_req_t *req;
1708 	u16 ignored;
1709 
1710 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1711 
1712 	if (!ret)
1713 		return ERR_PTR(-ENOMEM);
1714 
1715 	err = 0;
1716 	clnt = fid->clnt;
1717 
1718 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1719 	if (IS_ERR(req)) {
1720 		err = PTR_ERR(req);
1721 		goto error;
1722 	}
1723 
1724 	err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
1725 	if (err) {
1726 		trace_9p_protocol_dump(clnt, &req->rc);
1727 		p9_tag_remove(clnt, req);
1728 		goto error;
1729 	}
1730 
1731 	p9_debug(P9_DEBUG_9P,
1732 		"<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1733 		"<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1734 		"<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1735 		"<<<    uid=%d gid=%d n_muid=%d\n",
1736 		ret->size, ret->type, ret->dev, ret->qid.type,
1737 		(unsigned long long)ret->qid.path, ret->qid.version, ret->mode,
1738 		ret->atime, ret->mtime, (unsigned long long)ret->length,
1739 		ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1740 		from_kuid(&init_user_ns, ret->n_uid),
1741 		from_kgid(&init_user_ns, ret->n_gid),
1742 		from_kuid(&init_user_ns, ret->n_muid));
1743 
1744 	p9_tag_remove(clnt, req);
1745 	return ret;
1746 
1747 error:
1748 	kfree(ret);
1749 	return ERR_PTR(err);
1750 }
1751 EXPORT_SYMBOL(p9_client_stat);
1752 
1753 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1754 							u64 request_mask)
1755 {
1756 	int err;
1757 	struct p9_client *clnt;
1758 	struct p9_stat_dotl *ret = kmalloc(sizeof(struct p9_stat_dotl),
1759 								GFP_KERNEL);
1760 	struct p9_req_t *req;
1761 
1762 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1763 							fid->fid, request_mask);
1764 
1765 	if (!ret)
1766 		return ERR_PTR(-ENOMEM);
1767 
1768 	err = 0;
1769 	clnt = fid->clnt;
1770 
1771 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1772 	if (IS_ERR(req)) {
1773 		err = PTR_ERR(req);
1774 		goto error;
1775 	}
1776 
1777 	err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
1778 	if (err) {
1779 		trace_9p_protocol_dump(clnt, &req->rc);
1780 		p9_tag_remove(clnt, req);
1781 		goto error;
1782 	}
1783 
1784 	p9_debug(P9_DEBUG_9P,
1785 		"<<< RGETATTR st_result_mask=%lld\n"
1786 		"<<< qid=%x.%llx.%x\n"
1787 		"<<< st_mode=%8.8x st_nlink=%llu\n"
1788 		"<<< st_uid=%d st_gid=%d\n"
1789 		"<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1790 		"<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1791 		"<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1792 		"<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1793 		"<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1794 		"<<< st_gen=%lld st_data_version=%lld\n",
1795 		ret->st_result_mask, ret->qid.type, ret->qid.path,
1796 		ret->qid.version, ret->st_mode, ret->st_nlink,
1797 		from_kuid(&init_user_ns, ret->st_uid),
1798 		from_kgid(&init_user_ns, ret->st_gid),
1799 		ret->st_rdev, ret->st_size, ret->st_blksize,
1800 		ret->st_blocks, ret->st_atime_sec, ret->st_atime_nsec,
1801 		ret->st_mtime_sec, ret->st_mtime_nsec, ret->st_ctime_sec,
1802 		ret->st_ctime_nsec, ret->st_btime_sec, ret->st_btime_nsec,
1803 		ret->st_gen, ret->st_data_version);
1804 
1805 	p9_tag_remove(clnt, req);
1806 	return ret;
1807 
1808 error:
1809 	kfree(ret);
1810 	return ERR_PTR(err);
1811 }
1812 EXPORT_SYMBOL(p9_client_getattr_dotl);
1813 
1814 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1815 {
1816 	int ret;
1817 
1818 	/* NOTE: size shouldn't include its own length */
1819 	/* size[2] type[2] dev[4] qid[13] */
1820 	/* mode[4] atime[4] mtime[4] length[8]*/
1821 	/* name[s] uid[s] gid[s] muid[s] */
1822 	ret = 2+4+13+4+4+4+8+2+2+2+2;
1823 
1824 	if (wst->name)
1825 		ret += strlen(wst->name);
1826 	if (wst->uid)
1827 		ret += strlen(wst->uid);
1828 	if (wst->gid)
1829 		ret += strlen(wst->gid);
1830 	if (wst->muid)
1831 		ret += strlen(wst->muid);
1832 
1833 	if ((proto_version == p9_proto_2000u) ||
1834 		(proto_version == p9_proto_2000L)) {
1835 		ret += 2+4+4+4;	/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1836 		if (wst->extension)
1837 			ret += strlen(wst->extension);
1838 	}
1839 
1840 	return ret;
1841 }
1842 
1843 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1844 {
1845 	int err;
1846 	struct p9_req_t *req;
1847 	struct p9_client *clnt;
1848 
1849 	err = 0;
1850 	clnt = fid->clnt;
1851 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1852 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n", fid->fid);
1853 	p9_debug(P9_DEBUG_9P,
1854 		"     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1855 		"     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1856 		"     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1857 		"     uid=%d gid=%d n_muid=%d\n",
1858 		wst->size, wst->type, wst->dev, wst->qid.type,
1859 		(unsigned long long)wst->qid.path, wst->qid.version, wst->mode,
1860 		wst->atime, wst->mtime, (unsigned long long)wst->length,
1861 		wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1862 		from_kuid(&init_user_ns, wst->n_uid),
1863 		from_kgid(&init_user_ns, wst->n_gid),
1864 		from_kuid(&init_user_ns, wst->n_muid));
1865 
1866 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS", fid->fid, wst->size+2, wst);
1867 	if (IS_ERR(req)) {
1868 		err = PTR_ERR(req);
1869 		goto error;
1870 	}
1871 
1872 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1873 
1874 	p9_tag_remove(clnt, req);
1875 error:
1876 	return err;
1877 }
1878 EXPORT_SYMBOL(p9_client_wstat);
1879 
1880 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1881 {
1882 	int err;
1883 	struct p9_req_t *req;
1884 	struct p9_client *clnt;
1885 
1886 	err = 0;
1887 	clnt = fid->clnt;
1888 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1889 	p9_debug(P9_DEBUG_9P,
1890 		"    valid=%x mode=%x uid=%d gid=%d size=%lld\n"
1891 		"    atime_sec=%lld atime_nsec=%lld\n"
1892 		"    mtime_sec=%lld mtime_nsec=%lld\n",
1893 		p9attr->valid, p9attr->mode,
1894 		from_kuid(&init_user_ns, p9attr->uid),
1895 		from_kgid(&init_user_ns, p9attr->gid),
1896 		p9attr->size, p9attr->atime_sec, p9attr->atime_nsec,
1897 		p9attr->mtime_sec, p9attr->mtime_nsec);
1898 
1899 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1900 
1901 	if (IS_ERR(req)) {
1902 		err = PTR_ERR(req);
1903 		goto error;
1904 	}
1905 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1906 	p9_tag_remove(clnt, req);
1907 error:
1908 	return err;
1909 }
1910 EXPORT_SYMBOL(p9_client_setattr);
1911 
1912 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1913 {
1914 	int err;
1915 	struct p9_req_t *req;
1916 	struct p9_client *clnt;
1917 
1918 	err = 0;
1919 	clnt = fid->clnt;
1920 
1921 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1922 
1923 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1924 	if (IS_ERR(req)) {
1925 		err = PTR_ERR(req);
1926 		goto error;
1927 	}
1928 
1929 	err = p9pdu_readf(&req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1930 			  &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1931 			  &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1932 	if (err) {
1933 		trace_9p_protocol_dump(clnt, &req->rc);
1934 		p9_tag_remove(clnt, req);
1935 		goto error;
1936 	}
1937 
1938 	p9_debug(P9_DEBUG_9P, "<<< RSTATFS fid %d type 0x%lx bsize %ld "
1939 		"blocks %llu bfree %llu bavail %llu files %llu ffree %llu "
1940 		"fsid %llu namelen %ld\n",
1941 		fid->fid, (long unsigned int)sb->type, (long int)sb->bsize,
1942 		sb->blocks, sb->bfree, sb->bavail, sb->files,  sb->ffree,
1943 		sb->fsid, (long int)sb->namelen);
1944 
1945 	p9_tag_remove(clnt, req);
1946 error:
1947 	return err;
1948 }
1949 EXPORT_SYMBOL(p9_client_statfs);
1950 
1951 int p9_client_rename(struct p9_fid *fid,
1952 		     struct p9_fid *newdirfid, const char *name)
1953 {
1954 	int err;
1955 	struct p9_req_t *req;
1956 	struct p9_client *clnt;
1957 
1958 	err = 0;
1959 	clnt = fid->clnt;
1960 
1961 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1962 			fid->fid, newdirfid->fid, name);
1963 
1964 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1965 			newdirfid->fid, name);
1966 	if (IS_ERR(req)) {
1967 		err = PTR_ERR(req);
1968 		goto error;
1969 	}
1970 
1971 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1972 
1973 	p9_tag_remove(clnt, req);
1974 error:
1975 	return err;
1976 }
1977 EXPORT_SYMBOL(p9_client_rename);
1978 
1979 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
1980 		       struct p9_fid *newdirfid, const char *new_name)
1981 {
1982 	int err;
1983 	struct p9_req_t *req;
1984 	struct p9_client *clnt;
1985 
1986 	err = 0;
1987 	clnt = olddirfid->clnt;
1988 
1989 	p9_debug(P9_DEBUG_9P, ">>> TRENAMEAT olddirfid %d old name %s"
1990 		   " newdirfid %d new name %s\n", olddirfid->fid, old_name,
1991 		   newdirfid->fid, new_name);
1992 
1993 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
1994 			    old_name, newdirfid->fid, new_name);
1995 	if (IS_ERR(req)) {
1996 		err = PTR_ERR(req);
1997 		goto error;
1998 	}
1999 
2000 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
2001 		   newdirfid->fid, new_name);
2002 
2003 	p9_tag_remove(clnt, req);
2004 error:
2005 	return err;
2006 }
2007 EXPORT_SYMBOL(p9_client_renameat);
2008 
2009 /*
2010  * An xattrwalk without @attr_name gives the fid for the lisxattr namespace
2011  */
2012 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
2013 				const char *attr_name, u64 *attr_size)
2014 {
2015 	int err;
2016 	struct p9_req_t *req;
2017 	struct p9_client *clnt;
2018 	struct p9_fid *attr_fid;
2019 
2020 	err = 0;
2021 	clnt = file_fid->clnt;
2022 	attr_fid = p9_fid_create(clnt);
2023 	if (!attr_fid) {
2024 		err = -ENOMEM;
2025 		goto error;
2026 	}
2027 	p9_debug(P9_DEBUG_9P,
2028 		">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
2029 		file_fid->fid, attr_fid->fid, attr_name);
2030 
2031 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
2032 			file_fid->fid, attr_fid->fid, attr_name);
2033 	if (IS_ERR(req)) {
2034 		err = PTR_ERR(req);
2035 		goto error;
2036 	}
2037 	err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
2038 	if (err) {
2039 		trace_9p_protocol_dump(clnt, &req->rc);
2040 		p9_tag_remove(clnt, req);
2041 		goto clunk_fid;
2042 	}
2043 	p9_tag_remove(clnt, req);
2044 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
2045 		attr_fid->fid, *attr_size);
2046 	return attr_fid;
2047 clunk_fid:
2048 	p9_client_clunk(attr_fid);
2049 	attr_fid = NULL;
2050 error:
2051 	if (attr_fid && (attr_fid != file_fid))
2052 		p9_fid_destroy(attr_fid);
2053 
2054 	return ERR_PTR(err);
2055 }
2056 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
2057 
2058 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
2059 			u64 attr_size, int flags)
2060 {
2061 	int err;
2062 	struct p9_req_t *req;
2063 	struct p9_client *clnt;
2064 
2065 	p9_debug(P9_DEBUG_9P,
2066 		">>> TXATTRCREATE fid %d name  %s size %lld flag %d\n",
2067 		fid->fid, name, (long long)attr_size, flags);
2068 	err = 0;
2069 	clnt = fid->clnt;
2070 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
2071 			fid->fid, name, attr_size, flags);
2072 	if (IS_ERR(req)) {
2073 		err = PTR_ERR(req);
2074 		goto error;
2075 	}
2076 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
2077 	p9_tag_remove(clnt, req);
2078 error:
2079 	return err;
2080 }
2081 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
2082 
2083 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
2084 {
2085 	int err, rsize, non_zc = 0;
2086 	struct p9_client *clnt;
2087 	struct p9_req_t *req;
2088 	char *dataptr;
2089 	struct kvec kv = {.iov_base = data, .iov_len = count};
2090 	struct iov_iter to;
2091 
2092 	iov_iter_kvec(&to, READ, &kv, 1, count);
2093 
2094 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
2095 				fid->fid, (unsigned long long) offset, count);
2096 
2097 	err = 0;
2098 	clnt = fid->clnt;
2099 
2100 	rsize = fid->iounit;
2101 	if (!rsize || rsize > clnt->msize-P9_READDIRHDRSZ)
2102 		rsize = clnt->msize - P9_READDIRHDRSZ;
2103 
2104 	if (count < rsize)
2105 		rsize = count;
2106 
2107 	/* Don't bother zerocopy for small IO (< 1024) */
2108 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2109 		/*
2110 		 * response header len is 11
2111 		 * PDU Header(7) + IO Size (4)
2112 		 */
2113 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2114 				       11, "dqd", fid->fid, offset, rsize);
2115 	} else {
2116 		non_zc = 1;
2117 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2118 				    offset, rsize);
2119 	}
2120 	if (IS_ERR(req)) {
2121 		err = PTR_ERR(req);
2122 		goto error;
2123 	}
2124 
2125 	err = p9pdu_readf(&req->rc, clnt->proto_version, "D", &count, &dataptr);
2126 	if (err) {
2127 		trace_9p_protocol_dump(clnt, &req->rc);
2128 		goto free_and_error;
2129 	}
2130 	if (rsize < count) {
2131 		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
2132 		count = rsize;
2133 	}
2134 
2135 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
2136 
2137 	if (non_zc)
2138 		memmove(data, dataptr, count);
2139 
2140 	p9_tag_remove(clnt, req);
2141 	return count;
2142 
2143 free_and_error:
2144 	p9_tag_remove(clnt, req);
2145 error:
2146 	return err;
2147 }
2148 EXPORT_SYMBOL(p9_client_readdir);
2149 
2150 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2151 			dev_t rdev, kgid_t gid, struct p9_qid *qid)
2152 {
2153 	int err;
2154 	struct p9_client *clnt;
2155 	struct p9_req_t *req;
2156 
2157 	err = 0;
2158 	clnt = fid->clnt;
2159 	p9_debug(P9_DEBUG_9P, ">>> TMKNOD fid %d name %s mode %d major %d "
2160 		"minor %d\n", fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2161 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2162 		MAJOR(rdev), MINOR(rdev), gid);
2163 	if (IS_ERR(req))
2164 		return PTR_ERR(req);
2165 
2166 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2167 	if (err) {
2168 		trace_9p_protocol_dump(clnt, &req->rc);
2169 		goto error;
2170 	}
2171 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n", qid->type,
2172 				(unsigned long long)qid->path, qid->version);
2173 
2174 error:
2175 	p9_tag_remove(clnt, req);
2176 	return err;
2177 
2178 }
2179 EXPORT_SYMBOL(p9_client_mknod_dotl);
2180 
2181 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2182 				kgid_t gid, struct p9_qid *qid)
2183 {
2184 	int err;
2185 	struct p9_client *clnt;
2186 	struct p9_req_t *req;
2187 
2188 	err = 0;
2189 	clnt = fid->clnt;
2190 	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
2191 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
2192 	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg", fid->fid, name, mode,
2193 		gid);
2194 	if (IS_ERR(req))
2195 		return PTR_ERR(req);
2196 
2197 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2198 	if (err) {
2199 		trace_9p_protocol_dump(clnt, &req->rc);
2200 		goto error;
2201 	}
2202 	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
2203 				(unsigned long long)qid->path, qid->version);
2204 
2205 error:
2206 	p9_tag_remove(clnt, req);
2207 	return err;
2208 
2209 }
2210 EXPORT_SYMBOL(p9_client_mkdir_dotl);
2211 
2212 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
2213 {
2214 	int err;
2215 	struct p9_client *clnt;
2216 	struct p9_req_t *req;
2217 
2218 	err = 0;
2219 	clnt = fid->clnt;
2220 	p9_debug(P9_DEBUG_9P, ">>> TLOCK fid %d type %i flags %d "
2221 			"start %lld length %lld proc_id %d client_id %s\n",
2222 			fid->fid, flock->type, flock->flags, flock->start,
2223 			flock->length, flock->proc_id, flock->client_id);
2224 
2225 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2226 				flock->flags, flock->start, flock->length,
2227 					flock->proc_id, flock->client_id);
2228 
2229 	if (IS_ERR(req))
2230 		return PTR_ERR(req);
2231 
2232 	err = p9pdu_readf(&req->rc, clnt->proto_version, "b", status);
2233 	if (err) {
2234 		trace_9p_protocol_dump(clnt, &req->rc);
2235 		goto error;
2236 	}
2237 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2238 error:
2239 	p9_tag_remove(clnt, req);
2240 	return err;
2241 
2242 }
2243 EXPORT_SYMBOL(p9_client_lock_dotl);
2244 
2245 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2246 {
2247 	int err;
2248 	struct p9_client *clnt;
2249 	struct p9_req_t *req;
2250 
2251 	err = 0;
2252 	clnt = fid->clnt;
2253 	p9_debug(P9_DEBUG_9P, ">>> TGETLOCK fid %d, type %i start %lld "
2254 		"length %lld proc_id %d client_id %s\n", fid->fid, glock->type,
2255 		glock->start, glock->length, glock->proc_id, glock->client_id);
2256 
2257 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,  glock->type,
2258 		glock->start, glock->length, glock->proc_id, glock->client_id);
2259 
2260 	if (IS_ERR(req))
2261 		return PTR_ERR(req);
2262 
2263 	err = p9pdu_readf(&req->rc, clnt->proto_version, "bqqds", &glock->type,
2264 			  &glock->start, &glock->length, &glock->proc_id,
2265 			  &glock->client_id);
2266 	if (err) {
2267 		trace_9p_protocol_dump(clnt, &req->rc);
2268 		goto error;
2269 	}
2270 	p9_debug(P9_DEBUG_9P, "<<< RGETLOCK type %i start %lld length %lld "
2271 		"proc_id %d client_id %s\n", glock->type, glock->start,
2272 		glock->length, glock->proc_id, glock->client_id);
2273 error:
2274 	p9_tag_remove(clnt, req);
2275 	return err;
2276 }
2277 EXPORT_SYMBOL(p9_client_getlock_dotl);
2278 
2279 int p9_client_readlink(struct p9_fid *fid, char **target)
2280 {
2281 	int err;
2282 	struct p9_client *clnt;
2283 	struct p9_req_t *req;
2284 
2285 	err = 0;
2286 	clnt = fid->clnt;
2287 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2288 
2289 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2290 	if (IS_ERR(req))
2291 		return PTR_ERR(req);
2292 
2293 	err = p9pdu_readf(&req->rc, clnt->proto_version, "s", target);
2294 	if (err) {
2295 		trace_9p_protocol_dump(clnt, &req->rc);
2296 		goto error;
2297 	}
2298 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2299 error:
2300 	p9_tag_remove(clnt, req);
2301 	return err;
2302 }
2303 EXPORT_SYMBOL(p9_client_readlink);
2304 
2305 int __init p9_client_init(void)
2306 {
2307 	p9_req_cache = KMEM_CACHE(p9_req_t, SLAB_TYPESAFE_BY_RCU);
2308 	return p9_req_cache ? 0 : -ENOMEM;
2309 }
2310 
2311 void __exit p9_client_exit(void)
2312 {
2313 	kmem_cache_destroy(p9_req_cache);
2314 }
2315