xref: /linux/net/9p/client.c (revision 8a79db5e83a5d52c74e6f3c40d6f312cf899213e)
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  *
418  */
419 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
420 {
421 	p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc.tag);
422 
423 	/*
424 	 * This barrier is needed to make sure any change made to req before
425 	 * the status change is visible to another thread
426 	 */
427 	smp_wmb();
428 	req->status = status;
429 
430 	wake_up(&req->wq);
431 	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
432 	p9_req_put(req);
433 }
434 EXPORT_SYMBOL(p9_client_cb);
435 
436 /**
437  * p9_parse_header - parse header arguments out of a packet
438  * @pdu: packet to parse
439  * @size: size of packet
440  * @type: type of request
441  * @tag: tag of packet
442  * @rewind: set if we need to rewind offset afterwards
443  */
444 
445 int
446 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type, int16_t *tag,
447 								int rewind)
448 {
449 	int8_t r_type;
450 	int16_t r_tag;
451 	int32_t r_size;
452 	int offset = pdu->offset;
453 	int err;
454 
455 	pdu->offset = 0;
456 
457 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
458 	if (err)
459 		goto rewind_and_exit;
460 
461 	if (type)
462 		*type = r_type;
463 	if (tag)
464 		*tag = r_tag;
465 	if (size)
466 		*size = r_size;
467 
468 	if (pdu->size != r_size || r_size < 7) {
469 		err = -EINVAL;
470 		goto rewind_and_exit;
471 	}
472 
473 	pdu->id = r_type;
474 	pdu->tag = r_tag;
475 
476 	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
477 		 pdu->size, pdu->id, pdu->tag);
478 
479 rewind_and_exit:
480 	if (rewind)
481 		pdu->offset = offset;
482 	return err;
483 }
484 EXPORT_SYMBOL(p9_parse_header);
485 
486 /**
487  * p9_check_errors - check 9p packet for error return and process it
488  * @c: current client instance
489  * @req: request to parse and check for error conditions
490  *
491  * returns error code if one is discovered, otherwise returns 0
492  *
493  * this will have to be more complicated if we have multiple
494  * error packet types
495  */
496 
497 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
498 {
499 	int8_t type;
500 	int err;
501 	int ecode;
502 
503 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
504 	if (req->rc.size >= c->msize) {
505 		p9_debug(P9_DEBUG_ERROR,
506 			 "requested packet size too big: %d\n",
507 			 req->rc.size);
508 		return -EIO;
509 	}
510 	/*
511 	 * dump the response from server
512 	 * This should be after check errors which poplulate pdu_fcall.
513 	 */
514 	trace_9p_protocol_dump(c, &req->rc);
515 	if (err) {
516 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
517 		return err;
518 	}
519 	if (type != P9_RERROR && type != P9_RLERROR)
520 		return 0;
521 
522 	if (!p9_is_proto_dotl(c)) {
523 		char *ename;
524 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
525 				  &ename, &ecode);
526 		if (err)
527 			goto out_err;
528 
529 		if (p9_is_proto_dotu(c) && ecode < 512)
530 			err = -ecode;
531 
532 		if (!err) {
533 			err = p9_errstr2errno(ename, strlen(ename));
534 
535 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
536 				 -ecode, ename);
537 		}
538 		kfree(ename);
539 	} else {
540 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
541 		err = -ecode;
542 
543 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
544 	}
545 
546 	return err;
547 
548 out_err:
549 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
550 
551 	return err;
552 }
553 
554 /**
555  * p9_check_zc_errors - check 9p packet for error return and process it
556  * @c: current client instance
557  * @req: request to parse and check for error conditions
558  * @in_hdrlen: Size of response protocol buffer.
559  *
560  * returns error code if one is discovered, otherwise returns 0
561  *
562  * this will have to be more complicated if we have multiple
563  * error packet types
564  */
565 
566 static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
567 			      struct iov_iter *uidata, int in_hdrlen)
568 {
569 	int err;
570 	int ecode;
571 	int8_t type;
572 	char *ename = NULL;
573 
574 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
575 	/*
576 	 * dump the response from server
577 	 * This should be after parse_header which poplulate pdu_fcall.
578 	 */
579 	trace_9p_protocol_dump(c, &req->rc);
580 	if (err) {
581 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
582 		return err;
583 	}
584 
585 	if (type != P9_RERROR && type != P9_RLERROR)
586 		return 0;
587 
588 	if (!p9_is_proto_dotl(c)) {
589 		/* Error is reported in string format */
590 		int len;
591 		/* 7 = header size for RERROR; */
592 		int inline_len = in_hdrlen - 7;
593 
594 		len = req->rc.size - req->rc.offset;
595 		if (len > (P9_ZC_HDR_SZ - 7)) {
596 			err = -EFAULT;
597 			goto out_err;
598 		}
599 
600 		ename = &req->rc.sdata[req->rc.offset];
601 		if (len > inline_len) {
602 			/* We have error in external buffer */
603 			if (!copy_from_iter_full(ename + inline_len,
604 					     len - inline_len, uidata)) {
605 				err = -EFAULT;
606 				goto out_err;
607 			}
608 		}
609 		ename = NULL;
610 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
611 				  &ename, &ecode);
612 		if (err)
613 			goto out_err;
614 
615 		if (p9_is_proto_dotu(c) && ecode < 512)
616 			err = -ecode;
617 
618 		if (!err) {
619 			err = p9_errstr2errno(ename, strlen(ename));
620 
621 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
622 				 -ecode, ename);
623 		}
624 		kfree(ename);
625 	} else {
626 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
627 		err = -ecode;
628 
629 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
630 	}
631 	return err;
632 
633 out_err:
634 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
635 	return err;
636 }
637 
638 static struct p9_req_t *
639 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
640 
641 /**
642  * p9_client_flush - flush (cancel) a request
643  * @c: client state
644  * @oldreq: request to cancel
645  *
646  * This sents a flush for a particular request and links
647  * the flush request to the original request.  The current
648  * code only supports a single flush request although the protocol
649  * allows for multiple flush requests to be sent for a single request.
650  *
651  */
652 
653 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
654 {
655 	struct p9_req_t *req;
656 	int16_t oldtag;
657 	int err;
658 
659 	err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
660 	if (err)
661 		return err;
662 
663 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
664 
665 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
666 	if (IS_ERR(req))
667 		return PTR_ERR(req);
668 
669 	/*
670 	 * if we haven't received a response for oldreq,
671 	 * remove it from the list
672 	 */
673 	if (oldreq->status == REQ_STATUS_SENT) {
674 		if (c->trans_mod->cancelled)
675 			c->trans_mod->cancelled(c, oldreq);
676 	}
677 
678 	p9_tag_remove(c, req);
679 	return 0;
680 }
681 
682 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
683 					      int8_t type, int req_size,
684 					      const char *fmt, va_list ap)
685 {
686 	int err;
687 	struct p9_req_t *req;
688 
689 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
690 
691 	/* we allow for any status other than disconnected */
692 	if (c->status == Disconnected)
693 		return ERR_PTR(-EIO);
694 
695 	/* if status is begin_disconnected we allow only clunk request */
696 	if ((c->status == BeginDisconnect) && (type != P9_TCLUNK))
697 		return ERR_PTR(-EIO);
698 
699 	req = p9_tag_alloc(c, type, req_size);
700 	if (IS_ERR(req))
701 		return req;
702 
703 	/* marshall the data */
704 	p9pdu_prepare(&req->tc, req->tc.tag, type);
705 	err = p9pdu_vwritef(&req->tc, c->proto_version, fmt, ap);
706 	if (err)
707 		goto reterr;
708 	p9pdu_finalize(c, &req->tc);
709 	trace_9p_client_req(c, type, req->tc.tag);
710 	return req;
711 reterr:
712 	p9_tag_remove(c, req);
713 	/* We have to put also the 2nd reference as it won't be used */
714 	p9_req_put(req);
715 	return ERR_PTR(err);
716 }
717 
718 /**
719  * p9_client_rpc - issue a request and wait for a response
720  * @c: client session
721  * @type: type of request
722  * @fmt: protocol format string (see protocol.c)
723  *
724  * Returns request structure (which client must free using p9_tag_remove)
725  */
726 
727 static struct p9_req_t *
728 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
729 {
730 	va_list ap;
731 	int sigpending, err;
732 	unsigned long flags;
733 	struct p9_req_t *req;
734 
735 	va_start(ap, fmt);
736 	req = p9_client_prepare_req(c, type, c->msize, fmt, ap);
737 	va_end(ap);
738 	if (IS_ERR(req))
739 		return req;
740 
741 	if (signal_pending(current)) {
742 		sigpending = 1;
743 		clear_thread_flag(TIF_SIGPENDING);
744 	} else
745 		sigpending = 0;
746 
747 	err = c->trans_mod->request(c, req);
748 	if (err < 0) {
749 		/* write won't happen */
750 		p9_req_put(req);
751 		if (err != -ERESTARTSYS && err != -EFAULT)
752 			c->status = Disconnected;
753 		goto recalc_sigpending;
754 	}
755 again:
756 	/* Wait for the response */
757 	err = wait_event_killable(req->wq, req->status >= REQ_STATUS_RCVD);
758 
759 	/*
760 	 * Make sure our req is coherent with regard to updates in other
761 	 * threads - echoes to wmb() in the callback
762 	 */
763 	smp_rmb();
764 
765 	if ((err == -ERESTARTSYS) && (c->status == Connected)
766 				  && (type == P9_TFLUSH)) {
767 		sigpending = 1;
768 		clear_thread_flag(TIF_SIGPENDING);
769 		goto again;
770 	}
771 
772 	if (req->status == REQ_STATUS_ERROR) {
773 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
774 		err = req->t_err;
775 	}
776 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
777 		p9_debug(P9_DEBUG_MUX, "flushing\n");
778 		sigpending = 1;
779 		clear_thread_flag(TIF_SIGPENDING);
780 
781 		if (c->trans_mod->cancel(c, req))
782 			p9_client_flush(c, req);
783 
784 		/* if we received the response anyway, don't signal error */
785 		if (req->status == REQ_STATUS_RCVD)
786 			err = 0;
787 	}
788 recalc_sigpending:
789 	if (sigpending) {
790 		spin_lock_irqsave(&current->sighand->siglock, flags);
791 		recalc_sigpending();
792 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
793 	}
794 	if (err < 0)
795 		goto reterr;
796 
797 	err = p9_check_errors(c, req);
798 	trace_9p_client_res(c, type, req->rc.tag, err);
799 	if (!err)
800 		return req;
801 reterr:
802 	p9_tag_remove(c, req);
803 	return ERR_PTR(safe_errno(err));
804 }
805 
806 /**
807  * p9_client_zc_rpc - issue a request and wait for a response
808  * @c: client session
809  * @type: type of request
810  * @uidata: destination for zero copy read
811  * @uodata: source for zero copy write
812  * @inlen: read buffer size
813  * @olen: write buffer size
814  * @hdrlen: reader header size, This is the size of response protocol data
815  * @fmt: protocol format string (see protocol.c)
816  *
817  * Returns request structure (which client must free using p9_tag_remove)
818  */
819 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
820 					 struct iov_iter *uidata,
821 					 struct iov_iter *uodata,
822 					 int inlen, int olen, int in_hdrlen,
823 					 const char *fmt, ...)
824 {
825 	va_list ap;
826 	int sigpending, err;
827 	unsigned long flags;
828 	struct p9_req_t *req;
829 
830 	va_start(ap, fmt);
831 	/*
832 	 * We allocate a inline protocol data of only 4k bytes.
833 	 * The actual content is passed in zero-copy fashion.
834 	 */
835 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, fmt, ap);
836 	va_end(ap);
837 	if (IS_ERR(req))
838 		return req;
839 
840 	if (signal_pending(current)) {
841 		sigpending = 1;
842 		clear_thread_flag(TIF_SIGPENDING);
843 	} else
844 		sigpending = 0;
845 
846 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
847 				       inlen, olen, in_hdrlen);
848 	if (err < 0) {
849 		if (err == -EIO)
850 			c->status = Disconnected;
851 		if (err != -ERESTARTSYS)
852 			goto recalc_sigpending;
853 	}
854 	if (req->status == REQ_STATUS_ERROR) {
855 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
856 		err = req->t_err;
857 	}
858 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
859 		p9_debug(P9_DEBUG_MUX, "flushing\n");
860 		sigpending = 1;
861 		clear_thread_flag(TIF_SIGPENDING);
862 
863 		if (c->trans_mod->cancel(c, req))
864 			p9_client_flush(c, req);
865 
866 		/* if we received the response anyway, don't signal error */
867 		if (req->status == REQ_STATUS_RCVD)
868 			err = 0;
869 	}
870 recalc_sigpending:
871 	if (sigpending) {
872 		spin_lock_irqsave(&current->sighand->siglock, flags);
873 		recalc_sigpending();
874 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
875 	}
876 	if (err < 0)
877 		goto reterr;
878 
879 	err = p9_check_zc_errors(c, req, uidata, in_hdrlen);
880 	trace_9p_client_res(c, type, req->rc.tag, err);
881 	if (!err)
882 		return req;
883 reterr:
884 	p9_tag_remove(c, req);
885 	return ERR_PTR(safe_errno(err));
886 }
887 
888 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
889 {
890 	int ret;
891 	struct p9_fid *fid;
892 
893 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
894 	fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
895 	if (!fid)
896 		return NULL;
897 
898 	memset(&fid->qid, 0, sizeof(struct p9_qid));
899 	fid->mode = -1;
900 	fid->uid = current_fsuid();
901 	fid->clnt = clnt;
902 	fid->rdir = NULL;
903 	fid->fid = 0;
904 
905 	idr_preload(GFP_KERNEL);
906 	spin_lock_irq(&clnt->lock);
907 	ret = idr_alloc_u32(&clnt->fids, fid, &fid->fid, P9_NOFID - 1,
908 			    GFP_NOWAIT);
909 	spin_unlock_irq(&clnt->lock);
910 	idr_preload_end();
911 
912 	if (!ret)
913 		return fid;
914 
915 	kfree(fid);
916 	return NULL;
917 }
918 
919 static void p9_fid_destroy(struct p9_fid *fid)
920 {
921 	struct p9_client *clnt;
922 	unsigned long flags;
923 
924 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
925 	clnt = fid->clnt;
926 	spin_lock_irqsave(&clnt->lock, flags);
927 	idr_remove(&clnt->fids, fid->fid);
928 	spin_unlock_irqrestore(&clnt->lock, flags);
929 	kfree(fid->rdir);
930 	kfree(fid);
931 }
932 
933 static int p9_client_version(struct p9_client *c)
934 {
935 	int err = 0;
936 	struct p9_req_t *req;
937 	char *version = NULL;
938 	int msize;
939 
940 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
941 		 c->msize, c->proto_version);
942 
943 	switch (c->proto_version) {
944 	case p9_proto_2000L:
945 		req = p9_client_rpc(c, P9_TVERSION, "ds",
946 					c->msize, "9P2000.L");
947 		break;
948 	case p9_proto_2000u:
949 		req = p9_client_rpc(c, P9_TVERSION, "ds",
950 					c->msize, "9P2000.u");
951 		break;
952 	case p9_proto_legacy:
953 		req = p9_client_rpc(c, P9_TVERSION, "ds",
954 					c->msize, "9P2000");
955 		break;
956 	default:
957 		return -EINVAL;
958 	}
959 
960 	if (IS_ERR(req))
961 		return PTR_ERR(req);
962 
963 	err = p9pdu_readf(&req->rc, c->proto_version, "ds", &msize, &version);
964 	if (err) {
965 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
966 		trace_9p_protocol_dump(c, &req->rc);
967 		goto error;
968 	}
969 
970 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
971 	if (!strncmp(version, "9P2000.L", 8))
972 		c->proto_version = p9_proto_2000L;
973 	else if (!strncmp(version, "9P2000.u", 8))
974 		c->proto_version = p9_proto_2000u;
975 	else if (!strncmp(version, "9P2000", 6))
976 		c->proto_version = p9_proto_legacy;
977 	else {
978 		p9_debug(P9_DEBUG_ERROR,
979 			 "server returned an unknown version: %s\n", version);
980 		err = -EREMOTEIO;
981 		goto error;
982 	}
983 
984 	if (msize < 4096) {
985 		p9_debug(P9_DEBUG_ERROR,
986 			 "server returned a msize < 4096: %d\n", msize);
987 		err = -EREMOTEIO;
988 		goto error;
989 	}
990 	if (msize < c->msize)
991 		c->msize = msize;
992 
993 error:
994 	kfree(version);
995 	p9_tag_remove(c, req);
996 
997 	return err;
998 }
999 
1000 struct p9_client *p9_client_create(const char *dev_name, char *options)
1001 {
1002 	int err;
1003 	struct p9_client *clnt;
1004 	char *client_id;
1005 
1006 	err = 0;
1007 	clnt = kmalloc(sizeof(struct p9_client), GFP_KERNEL);
1008 	if (!clnt)
1009 		return ERR_PTR(-ENOMEM);
1010 
1011 	clnt->trans_mod = NULL;
1012 	clnt->trans = NULL;
1013 	clnt->fcall_cache = NULL;
1014 
1015 	client_id = utsname()->nodename;
1016 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
1017 
1018 	spin_lock_init(&clnt->lock);
1019 	idr_init(&clnt->fids);
1020 	idr_init(&clnt->reqs);
1021 
1022 	err = parse_opts(options, clnt);
1023 	if (err < 0)
1024 		goto free_client;
1025 
1026 	if (!clnt->trans_mod)
1027 		clnt->trans_mod = v9fs_get_default_trans();
1028 
1029 	if (clnt->trans_mod == NULL) {
1030 		err = -EPROTONOSUPPORT;
1031 		p9_debug(P9_DEBUG_ERROR,
1032 			 "No transport defined or default transport\n");
1033 		goto free_client;
1034 	}
1035 
1036 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
1037 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
1038 
1039 	err = clnt->trans_mod->create(clnt, dev_name, options);
1040 	if (err)
1041 		goto put_trans;
1042 
1043 	if (clnt->msize > clnt->trans_mod->maxsize)
1044 		clnt->msize = clnt->trans_mod->maxsize;
1045 
1046 	if (clnt->msize < 4096) {
1047 		p9_debug(P9_DEBUG_ERROR,
1048 			 "Please specify a msize of at least 4k\n");
1049 		err = -EINVAL;
1050 		goto close_trans;
1051 	}
1052 
1053 	err = p9_client_version(clnt);
1054 	if (err)
1055 		goto close_trans;
1056 
1057 	/* P9_HDRSZ + 4 is the smallest packet header we can have that is
1058 	 * followed by data accessed from userspace by read
1059 	 */
1060 	clnt->fcall_cache =
1061 		kmem_cache_create_usercopy("9p-fcall-cache", clnt->msize,
1062 					   0, 0, P9_HDRSZ + 4,
1063 					   clnt->msize - (P9_HDRSZ + 4),
1064 					   NULL);
1065 
1066 	return clnt;
1067 
1068 close_trans:
1069 	clnt->trans_mod->close(clnt);
1070 put_trans:
1071 	v9fs_put_trans(clnt->trans_mod);
1072 free_client:
1073 	kfree(clnt);
1074 	return ERR_PTR(err);
1075 }
1076 EXPORT_SYMBOL(p9_client_create);
1077 
1078 void p9_client_destroy(struct p9_client *clnt)
1079 {
1080 	struct p9_fid *fid;
1081 	int id;
1082 
1083 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1084 
1085 	if (clnt->trans_mod)
1086 		clnt->trans_mod->close(clnt);
1087 
1088 	v9fs_put_trans(clnt->trans_mod);
1089 
1090 	idr_for_each_entry(&clnt->fids, fid, id) {
1091 		pr_info("Found fid %d not clunked\n", fid->fid);
1092 		p9_fid_destroy(fid);
1093 	}
1094 
1095 	p9_tag_cleanup(clnt);
1096 
1097 	kmem_cache_destroy(clnt->fcall_cache);
1098 	kfree(clnt);
1099 }
1100 EXPORT_SYMBOL(p9_client_destroy);
1101 
1102 void p9_client_disconnect(struct p9_client *clnt)
1103 {
1104 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1105 	clnt->status = Disconnected;
1106 }
1107 EXPORT_SYMBOL(p9_client_disconnect);
1108 
1109 void p9_client_begin_disconnect(struct p9_client *clnt)
1110 {
1111 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1112 	clnt->status = BeginDisconnect;
1113 }
1114 EXPORT_SYMBOL(p9_client_begin_disconnect);
1115 
1116 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1117 	const char *uname, kuid_t n_uname, const char *aname)
1118 {
1119 	int err = 0;
1120 	struct p9_req_t *req;
1121 	struct p9_fid *fid;
1122 	struct p9_qid qid;
1123 
1124 
1125 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1126 		 afid ? afid->fid : -1, uname, aname);
1127 	fid = p9_fid_create(clnt);
1128 	if (!fid) {
1129 		err = -ENOMEM;
1130 		goto error;
1131 	}
1132 	fid->uid = n_uname;
1133 
1134 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
1135 			afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
1136 	if (IS_ERR(req)) {
1137 		err = PTR_ERR(req);
1138 		goto error;
1139 	}
1140 
1141 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", &qid);
1142 	if (err) {
1143 		trace_9p_protocol_dump(clnt, &req->rc);
1144 		p9_tag_remove(clnt, req);
1145 		goto error;
1146 	}
1147 
1148 	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
1149 		 qid.type, (unsigned long long)qid.path, qid.version);
1150 
1151 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1152 
1153 	p9_tag_remove(clnt, req);
1154 	return fid;
1155 
1156 error:
1157 	if (fid)
1158 		p9_fid_destroy(fid);
1159 	return ERR_PTR(err);
1160 }
1161 EXPORT_SYMBOL(p9_client_attach);
1162 
1163 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
1164 		const unsigned char * const *wnames, int clone)
1165 {
1166 	int err;
1167 	struct p9_client *clnt;
1168 	struct p9_fid *fid;
1169 	struct p9_qid *wqids;
1170 	struct p9_req_t *req;
1171 	uint16_t nwqids, count;
1172 
1173 	err = 0;
1174 	wqids = NULL;
1175 	clnt = oldfid->clnt;
1176 	if (clone) {
1177 		fid = p9_fid_create(clnt);
1178 		if (!fid) {
1179 			err = -ENOMEM;
1180 			goto error;
1181 		}
1182 
1183 		fid->uid = oldfid->uid;
1184 	} else
1185 		fid = oldfid;
1186 
1187 
1188 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1189 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1190 
1191 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1192 								nwname, wnames);
1193 	if (IS_ERR(req)) {
1194 		err = PTR_ERR(req);
1195 		goto error;
1196 	}
1197 
1198 	err = p9pdu_readf(&req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1199 	if (err) {
1200 		trace_9p_protocol_dump(clnt, &req->rc);
1201 		p9_tag_remove(clnt, req);
1202 		goto clunk_fid;
1203 	}
1204 	p9_tag_remove(clnt, req);
1205 
1206 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1207 
1208 	if (nwqids != nwname) {
1209 		err = -ENOENT;
1210 		goto clunk_fid;
1211 	}
1212 
1213 	for (count = 0; count < nwqids; count++)
1214 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1215 			count, wqids[count].type,
1216 			(unsigned long long)wqids[count].path,
1217 			wqids[count].version);
1218 
1219 	if (nwname)
1220 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1221 	else
1222 		fid->qid = oldfid->qid;
1223 
1224 	kfree(wqids);
1225 	return fid;
1226 
1227 clunk_fid:
1228 	kfree(wqids);
1229 	p9_client_clunk(fid);
1230 	fid = NULL;
1231 
1232 error:
1233 	if (fid && (fid != oldfid))
1234 		p9_fid_destroy(fid);
1235 
1236 	return ERR_PTR(err);
1237 }
1238 EXPORT_SYMBOL(p9_client_walk);
1239 
1240 int p9_client_open(struct p9_fid *fid, int mode)
1241 {
1242 	int err;
1243 	struct p9_client *clnt;
1244 	struct p9_req_t *req;
1245 	struct p9_qid qid;
1246 	int iounit;
1247 
1248 	clnt = fid->clnt;
1249 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1250 		p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1251 	err = 0;
1252 
1253 	if (fid->mode != -1)
1254 		return -EINVAL;
1255 
1256 	if (p9_is_proto_dotl(clnt))
1257 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode);
1258 	else
1259 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
1260 	if (IS_ERR(req)) {
1261 		err = PTR_ERR(req);
1262 		goto error;
1263 	}
1264 
1265 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1266 	if (err) {
1267 		trace_9p_protocol_dump(clnt, &req->rc);
1268 		goto free_and_error;
1269 	}
1270 
1271 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1272 		p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1273 		(unsigned long long)qid.path, qid.version, iounit);
1274 
1275 	fid->mode = mode;
1276 	fid->iounit = iounit;
1277 
1278 free_and_error:
1279 	p9_tag_remove(clnt, req);
1280 error:
1281 	return err;
1282 }
1283 EXPORT_SYMBOL(p9_client_open);
1284 
1285 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags, u32 mode,
1286 		kgid_t gid, struct p9_qid *qid)
1287 {
1288 	int err = 0;
1289 	struct p9_client *clnt;
1290 	struct p9_req_t *req;
1291 	int iounit;
1292 
1293 	p9_debug(P9_DEBUG_9P,
1294 			">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1295 			ofid->fid, name, flags, mode,
1296 		 	from_kgid(&init_user_ns, gid));
1297 	clnt = ofid->clnt;
1298 
1299 	if (ofid->mode != -1)
1300 		return -EINVAL;
1301 
1302 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1303 			mode, gid);
1304 	if (IS_ERR(req)) {
1305 		err = PTR_ERR(req);
1306 		goto error;
1307 	}
1308 
1309 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", qid, &iounit);
1310 	if (err) {
1311 		trace_9p_protocol_dump(clnt, &req->rc);
1312 		goto free_and_error;
1313 	}
1314 
1315 	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1316 			qid->type,
1317 			(unsigned long long)qid->path,
1318 			qid->version, iounit);
1319 
1320 	ofid->mode = mode;
1321 	ofid->iounit = iounit;
1322 
1323 free_and_error:
1324 	p9_tag_remove(clnt, req);
1325 error:
1326 	return err;
1327 }
1328 EXPORT_SYMBOL(p9_client_create_dotl);
1329 
1330 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1331 		     char *extension)
1332 {
1333 	int err;
1334 	struct p9_client *clnt;
1335 	struct p9_req_t *req;
1336 	struct p9_qid qid;
1337 	int iounit;
1338 
1339 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1340 						fid->fid, name, perm, mode);
1341 	err = 0;
1342 	clnt = fid->clnt;
1343 
1344 	if (fid->mode != -1)
1345 		return -EINVAL;
1346 
1347 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1348 				mode, extension);
1349 	if (IS_ERR(req)) {
1350 		err = PTR_ERR(req);
1351 		goto error;
1352 	}
1353 
1354 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1355 	if (err) {
1356 		trace_9p_protocol_dump(clnt, &req->rc);
1357 		goto free_and_error;
1358 	}
1359 
1360 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1361 				qid.type,
1362 				(unsigned long long)qid.path,
1363 				qid.version, iounit);
1364 
1365 	fid->mode = mode;
1366 	fid->iounit = iounit;
1367 
1368 free_and_error:
1369 	p9_tag_remove(clnt, req);
1370 error:
1371 	return err;
1372 }
1373 EXPORT_SYMBOL(p9_client_fcreate);
1374 
1375 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1376 		const char *symtgt, kgid_t gid, struct p9_qid *qid)
1377 {
1378 	int err = 0;
1379 	struct p9_client *clnt;
1380 	struct p9_req_t *req;
1381 
1382 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1383 			dfid->fid, name, symtgt);
1384 	clnt = dfid->clnt;
1385 
1386 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1387 			gid);
1388 	if (IS_ERR(req)) {
1389 		err = PTR_ERR(req);
1390 		goto error;
1391 	}
1392 
1393 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
1394 	if (err) {
1395 		trace_9p_protocol_dump(clnt, &req->rc);
1396 		goto free_and_error;
1397 	}
1398 
1399 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1400 			qid->type, (unsigned long long)qid->path, qid->version);
1401 
1402 free_and_error:
1403 	p9_tag_remove(clnt, req);
1404 error:
1405 	return err;
1406 }
1407 EXPORT_SYMBOL(p9_client_symlink);
1408 
1409 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1410 {
1411 	struct p9_client *clnt;
1412 	struct p9_req_t *req;
1413 
1414 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1415 			dfid->fid, oldfid->fid, newname);
1416 	clnt = dfid->clnt;
1417 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1418 			newname);
1419 	if (IS_ERR(req))
1420 		return PTR_ERR(req);
1421 
1422 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1423 	p9_tag_remove(clnt, req);
1424 	return 0;
1425 }
1426 EXPORT_SYMBOL(p9_client_link);
1427 
1428 int p9_client_fsync(struct p9_fid *fid, int datasync)
1429 {
1430 	int err;
1431 	struct p9_client *clnt;
1432 	struct p9_req_t *req;
1433 
1434 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1435 			fid->fid, datasync);
1436 	err = 0;
1437 	clnt = fid->clnt;
1438 
1439 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1440 	if (IS_ERR(req)) {
1441 		err = PTR_ERR(req);
1442 		goto error;
1443 	}
1444 
1445 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1446 
1447 	p9_tag_remove(clnt, req);
1448 
1449 error:
1450 	return err;
1451 }
1452 EXPORT_SYMBOL(p9_client_fsync);
1453 
1454 int p9_client_clunk(struct p9_fid *fid)
1455 {
1456 	int err;
1457 	struct p9_client *clnt;
1458 	struct p9_req_t *req;
1459 	int retries = 0;
1460 
1461 	if (!fid) {
1462 		pr_warn("%s (%d): Trying to clunk with NULL fid\n",
1463 			__func__, task_pid_nr(current));
1464 		dump_stack();
1465 		return 0;
1466 	}
1467 
1468 again:
1469 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n", fid->fid,
1470 								retries);
1471 	err = 0;
1472 	clnt = fid->clnt;
1473 
1474 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1475 	if (IS_ERR(req)) {
1476 		err = PTR_ERR(req);
1477 		goto error;
1478 	}
1479 
1480 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1481 
1482 	p9_tag_remove(clnt, req);
1483 error:
1484 	/*
1485 	 * Fid is not valid even after a failed clunk
1486 	 * If interrupted, retry once then give up and
1487 	 * leak fid until umount.
1488 	 */
1489 	if (err == -ERESTARTSYS) {
1490 		if (retries++ == 0)
1491 			goto again;
1492 	} else
1493 		p9_fid_destroy(fid);
1494 	return err;
1495 }
1496 EXPORT_SYMBOL(p9_client_clunk);
1497 
1498 int p9_client_remove(struct p9_fid *fid)
1499 {
1500 	int err;
1501 	struct p9_client *clnt;
1502 	struct p9_req_t *req;
1503 
1504 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1505 	err = 0;
1506 	clnt = fid->clnt;
1507 
1508 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1509 	if (IS_ERR(req)) {
1510 		err = PTR_ERR(req);
1511 		goto error;
1512 	}
1513 
1514 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1515 
1516 	p9_tag_remove(clnt, req);
1517 error:
1518 	if (err == -ERESTARTSYS)
1519 		p9_client_clunk(fid);
1520 	else
1521 		p9_fid_destroy(fid);
1522 	return err;
1523 }
1524 EXPORT_SYMBOL(p9_client_remove);
1525 
1526 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1527 {
1528 	int err = 0;
1529 	struct p9_req_t *req;
1530 	struct p9_client *clnt;
1531 
1532 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1533 		   dfid->fid, name, flags);
1534 
1535 	clnt = dfid->clnt;
1536 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1537 	if (IS_ERR(req)) {
1538 		err = PTR_ERR(req);
1539 		goto error;
1540 	}
1541 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1542 
1543 	p9_tag_remove(clnt, req);
1544 error:
1545 	return err;
1546 }
1547 EXPORT_SYMBOL(p9_client_unlinkat);
1548 
1549 int
1550 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1551 {
1552 	struct p9_client *clnt = fid->clnt;
1553 	struct p9_req_t *req;
1554 	int total = 0;
1555 	*err = 0;
1556 
1557 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n",
1558 		   fid->fid, (unsigned long long) offset, (int)iov_iter_count(to));
1559 
1560 	while (iov_iter_count(to)) {
1561 		int count = iov_iter_count(to);
1562 		int rsize, non_zc = 0;
1563 		char *dataptr;
1564 
1565 		rsize = fid->iounit;
1566 		if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1567 			rsize = clnt->msize - P9_IOHDRSZ;
1568 
1569 		if (count < rsize)
1570 			rsize = count;
1571 
1572 		/* Don't bother zerocopy for small IO (< 1024) */
1573 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1574 			/*
1575 			 * response header len is 11
1576 			 * PDU Header(7) + IO Size (4)
1577 			 */
1578 			req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1579 					       0, 11, "dqd", fid->fid,
1580 					       offset, rsize);
1581 		} else {
1582 			non_zc = 1;
1583 			req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1584 					    rsize);
1585 		}
1586 		if (IS_ERR(req)) {
1587 			*err = PTR_ERR(req);
1588 			break;
1589 		}
1590 
1591 		*err = p9pdu_readf(&req->rc, clnt->proto_version,
1592 				   "D", &count, &dataptr);
1593 		if (*err) {
1594 			trace_9p_protocol_dump(clnt, &req->rc);
1595 			p9_tag_remove(clnt, req);
1596 			break;
1597 		}
1598 		if (rsize < count) {
1599 			pr_err("bogus RREAD count (%d > %d)\n", count, rsize);
1600 			count = rsize;
1601 		}
1602 
1603 		p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1604 		if (!count) {
1605 			p9_tag_remove(clnt, req);
1606 			break;
1607 		}
1608 
1609 		if (non_zc) {
1610 			int n = copy_to_iter(dataptr, count, to);
1611 			total += n;
1612 			offset += n;
1613 			if (n != count) {
1614 				*err = -EFAULT;
1615 				p9_tag_remove(clnt, req);
1616 				break;
1617 			}
1618 		} else {
1619 			iov_iter_advance(to, count);
1620 			total += count;
1621 			offset += count;
1622 		}
1623 		p9_tag_remove(clnt, req);
1624 	}
1625 	return total;
1626 }
1627 EXPORT_SYMBOL(p9_client_read);
1628 
1629 int
1630 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1631 {
1632 	struct p9_client *clnt = fid->clnt;
1633 	struct p9_req_t *req;
1634 	int total = 0;
1635 	*err = 0;
1636 
1637 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n",
1638 				fid->fid, (unsigned long long) offset,
1639 				iov_iter_count(from));
1640 
1641 	while (iov_iter_count(from)) {
1642 		int count = iov_iter_count(from);
1643 		int rsize = fid->iounit;
1644 		if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1645 			rsize = clnt->msize - P9_IOHDRSZ;
1646 
1647 		if (count < rsize)
1648 			rsize = count;
1649 
1650 		/* Don't bother zerocopy for small IO (< 1024) */
1651 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1652 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1653 					       rsize, P9_ZC_HDR_SZ, "dqd",
1654 					       fid->fid, offset, rsize);
1655 		} else {
1656 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1657 						    offset, rsize, from);
1658 		}
1659 		if (IS_ERR(req)) {
1660 			*err = PTR_ERR(req);
1661 			break;
1662 		}
1663 
1664 		*err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &count);
1665 		if (*err) {
1666 			trace_9p_protocol_dump(clnt, &req->rc);
1667 			p9_tag_remove(clnt, req);
1668 			break;
1669 		}
1670 		if (rsize < count) {
1671 			pr_err("bogus RWRITE count (%d > %d)\n", count, rsize);
1672 			count = rsize;
1673 		}
1674 
1675 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1676 
1677 		p9_tag_remove(clnt, req);
1678 		iov_iter_advance(from, count);
1679 		total += count;
1680 		offset += count;
1681 	}
1682 	return total;
1683 }
1684 EXPORT_SYMBOL(p9_client_write);
1685 
1686 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1687 {
1688 	int err;
1689 	struct p9_client *clnt;
1690 	struct p9_wstat *ret = kmalloc(sizeof(struct p9_wstat), GFP_KERNEL);
1691 	struct p9_req_t *req;
1692 	u16 ignored;
1693 
1694 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1695 
1696 	if (!ret)
1697 		return ERR_PTR(-ENOMEM);
1698 
1699 	err = 0;
1700 	clnt = fid->clnt;
1701 
1702 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1703 	if (IS_ERR(req)) {
1704 		err = PTR_ERR(req);
1705 		goto error;
1706 	}
1707 
1708 	err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
1709 	if (err) {
1710 		trace_9p_protocol_dump(clnt, &req->rc);
1711 		p9_tag_remove(clnt, req);
1712 		goto error;
1713 	}
1714 
1715 	p9_debug(P9_DEBUG_9P,
1716 		"<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1717 		"<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1718 		"<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1719 		"<<<    uid=%d gid=%d n_muid=%d\n",
1720 		ret->size, ret->type, ret->dev, ret->qid.type,
1721 		(unsigned long long)ret->qid.path, ret->qid.version, ret->mode,
1722 		ret->atime, ret->mtime, (unsigned long long)ret->length,
1723 		ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1724 		from_kuid(&init_user_ns, ret->n_uid),
1725 		from_kgid(&init_user_ns, ret->n_gid),
1726 		from_kuid(&init_user_ns, ret->n_muid));
1727 
1728 	p9_tag_remove(clnt, req);
1729 	return ret;
1730 
1731 error:
1732 	kfree(ret);
1733 	return ERR_PTR(err);
1734 }
1735 EXPORT_SYMBOL(p9_client_stat);
1736 
1737 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1738 							u64 request_mask)
1739 {
1740 	int err;
1741 	struct p9_client *clnt;
1742 	struct p9_stat_dotl *ret = kmalloc(sizeof(struct p9_stat_dotl),
1743 								GFP_KERNEL);
1744 	struct p9_req_t *req;
1745 
1746 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1747 							fid->fid, request_mask);
1748 
1749 	if (!ret)
1750 		return ERR_PTR(-ENOMEM);
1751 
1752 	err = 0;
1753 	clnt = fid->clnt;
1754 
1755 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1756 	if (IS_ERR(req)) {
1757 		err = PTR_ERR(req);
1758 		goto error;
1759 	}
1760 
1761 	err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
1762 	if (err) {
1763 		trace_9p_protocol_dump(clnt, &req->rc);
1764 		p9_tag_remove(clnt, req);
1765 		goto error;
1766 	}
1767 
1768 	p9_debug(P9_DEBUG_9P,
1769 		"<<< RGETATTR st_result_mask=%lld\n"
1770 		"<<< qid=%x.%llx.%x\n"
1771 		"<<< st_mode=%8.8x st_nlink=%llu\n"
1772 		"<<< st_uid=%d st_gid=%d\n"
1773 		"<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1774 		"<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1775 		"<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1776 		"<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1777 		"<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1778 		"<<< st_gen=%lld st_data_version=%lld\n",
1779 		ret->st_result_mask, ret->qid.type, ret->qid.path,
1780 		ret->qid.version, ret->st_mode, ret->st_nlink,
1781 		from_kuid(&init_user_ns, ret->st_uid),
1782 		from_kgid(&init_user_ns, ret->st_gid),
1783 		ret->st_rdev, ret->st_size, ret->st_blksize,
1784 		ret->st_blocks, ret->st_atime_sec, ret->st_atime_nsec,
1785 		ret->st_mtime_sec, ret->st_mtime_nsec, ret->st_ctime_sec,
1786 		ret->st_ctime_nsec, ret->st_btime_sec, ret->st_btime_nsec,
1787 		ret->st_gen, ret->st_data_version);
1788 
1789 	p9_tag_remove(clnt, req);
1790 	return ret;
1791 
1792 error:
1793 	kfree(ret);
1794 	return ERR_PTR(err);
1795 }
1796 EXPORT_SYMBOL(p9_client_getattr_dotl);
1797 
1798 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1799 {
1800 	int ret;
1801 
1802 	/* NOTE: size shouldn't include its own length */
1803 	/* size[2] type[2] dev[4] qid[13] */
1804 	/* mode[4] atime[4] mtime[4] length[8]*/
1805 	/* name[s] uid[s] gid[s] muid[s] */
1806 	ret = 2+4+13+4+4+4+8+2+2+2+2;
1807 
1808 	if (wst->name)
1809 		ret += strlen(wst->name);
1810 	if (wst->uid)
1811 		ret += strlen(wst->uid);
1812 	if (wst->gid)
1813 		ret += strlen(wst->gid);
1814 	if (wst->muid)
1815 		ret += strlen(wst->muid);
1816 
1817 	if ((proto_version == p9_proto_2000u) ||
1818 		(proto_version == p9_proto_2000L)) {
1819 		ret += 2+4+4+4;	/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1820 		if (wst->extension)
1821 			ret += strlen(wst->extension);
1822 	}
1823 
1824 	return ret;
1825 }
1826 
1827 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1828 {
1829 	int err;
1830 	struct p9_req_t *req;
1831 	struct p9_client *clnt;
1832 
1833 	err = 0;
1834 	clnt = fid->clnt;
1835 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1836 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n", fid->fid);
1837 	p9_debug(P9_DEBUG_9P,
1838 		"     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1839 		"     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1840 		"     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1841 		"     uid=%d gid=%d n_muid=%d\n",
1842 		wst->size, wst->type, wst->dev, wst->qid.type,
1843 		(unsigned long long)wst->qid.path, wst->qid.version, wst->mode,
1844 		wst->atime, wst->mtime, (unsigned long long)wst->length,
1845 		wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1846 		from_kuid(&init_user_ns, wst->n_uid),
1847 		from_kgid(&init_user_ns, wst->n_gid),
1848 		from_kuid(&init_user_ns, wst->n_muid));
1849 
1850 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS", fid->fid, wst->size+2, wst);
1851 	if (IS_ERR(req)) {
1852 		err = PTR_ERR(req);
1853 		goto error;
1854 	}
1855 
1856 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1857 
1858 	p9_tag_remove(clnt, req);
1859 error:
1860 	return err;
1861 }
1862 EXPORT_SYMBOL(p9_client_wstat);
1863 
1864 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1865 {
1866 	int err;
1867 	struct p9_req_t *req;
1868 	struct p9_client *clnt;
1869 
1870 	err = 0;
1871 	clnt = fid->clnt;
1872 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1873 	p9_debug(P9_DEBUG_9P,
1874 		"    valid=%x mode=%x uid=%d gid=%d size=%lld\n"
1875 		"    atime_sec=%lld atime_nsec=%lld\n"
1876 		"    mtime_sec=%lld mtime_nsec=%lld\n",
1877 		p9attr->valid, p9attr->mode,
1878 		from_kuid(&init_user_ns, p9attr->uid),
1879 		from_kgid(&init_user_ns, p9attr->gid),
1880 		p9attr->size, p9attr->atime_sec, p9attr->atime_nsec,
1881 		p9attr->mtime_sec, p9attr->mtime_nsec);
1882 
1883 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1884 
1885 	if (IS_ERR(req)) {
1886 		err = PTR_ERR(req);
1887 		goto error;
1888 	}
1889 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1890 	p9_tag_remove(clnt, req);
1891 error:
1892 	return err;
1893 }
1894 EXPORT_SYMBOL(p9_client_setattr);
1895 
1896 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1897 {
1898 	int err;
1899 	struct p9_req_t *req;
1900 	struct p9_client *clnt;
1901 
1902 	err = 0;
1903 	clnt = fid->clnt;
1904 
1905 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1906 
1907 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1908 	if (IS_ERR(req)) {
1909 		err = PTR_ERR(req);
1910 		goto error;
1911 	}
1912 
1913 	err = p9pdu_readf(&req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1914 			  &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1915 			  &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1916 	if (err) {
1917 		trace_9p_protocol_dump(clnt, &req->rc);
1918 		p9_tag_remove(clnt, req);
1919 		goto error;
1920 	}
1921 
1922 	p9_debug(P9_DEBUG_9P, "<<< RSTATFS fid %d type 0x%lx bsize %ld "
1923 		"blocks %llu bfree %llu bavail %llu files %llu ffree %llu "
1924 		"fsid %llu namelen %ld\n",
1925 		fid->fid, (long unsigned int)sb->type, (long int)sb->bsize,
1926 		sb->blocks, sb->bfree, sb->bavail, sb->files,  sb->ffree,
1927 		sb->fsid, (long int)sb->namelen);
1928 
1929 	p9_tag_remove(clnt, req);
1930 error:
1931 	return err;
1932 }
1933 EXPORT_SYMBOL(p9_client_statfs);
1934 
1935 int p9_client_rename(struct p9_fid *fid,
1936 		     struct p9_fid *newdirfid, const char *name)
1937 {
1938 	int err;
1939 	struct p9_req_t *req;
1940 	struct p9_client *clnt;
1941 
1942 	err = 0;
1943 	clnt = fid->clnt;
1944 
1945 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1946 			fid->fid, newdirfid->fid, name);
1947 
1948 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1949 			newdirfid->fid, name);
1950 	if (IS_ERR(req)) {
1951 		err = PTR_ERR(req);
1952 		goto error;
1953 	}
1954 
1955 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1956 
1957 	p9_tag_remove(clnt, req);
1958 error:
1959 	return err;
1960 }
1961 EXPORT_SYMBOL(p9_client_rename);
1962 
1963 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
1964 		       struct p9_fid *newdirfid, const char *new_name)
1965 {
1966 	int err;
1967 	struct p9_req_t *req;
1968 	struct p9_client *clnt;
1969 
1970 	err = 0;
1971 	clnt = olddirfid->clnt;
1972 
1973 	p9_debug(P9_DEBUG_9P, ">>> TRENAMEAT olddirfid %d old name %s"
1974 		   " newdirfid %d new name %s\n", olddirfid->fid, old_name,
1975 		   newdirfid->fid, new_name);
1976 
1977 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
1978 			    old_name, newdirfid->fid, new_name);
1979 	if (IS_ERR(req)) {
1980 		err = PTR_ERR(req);
1981 		goto error;
1982 	}
1983 
1984 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
1985 		   newdirfid->fid, new_name);
1986 
1987 	p9_tag_remove(clnt, req);
1988 error:
1989 	return err;
1990 }
1991 EXPORT_SYMBOL(p9_client_renameat);
1992 
1993 /*
1994  * An xattrwalk without @attr_name gives the fid for the lisxattr namespace
1995  */
1996 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
1997 				const char *attr_name, u64 *attr_size)
1998 {
1999 	int err;
2000 	struct p9_req_t *req;
2001 	struct p9_client *clnt;
2002 	struct p9_fid *attr_fid;
2003 
2004 	err = 0;
2005 	clnt = file_fid->clnt;
2006 	attr_fid = p9_fid_create(clnt);
2007 	if (!attr_fid) {
2008 		err = -ENOMEM;
2009 		goto error;
2010 	}
2011 	p9_debug(P9_DEBUG_9P,
2012 		">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
2013 		file_fid->fid, attr_fid->fid, attr_name);
2014 
2015 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
2016 			file_fid->fid, attr_fid->fid, attr_name);
2017 	if (IS_ERR(req)) {
2018 		err = PTR_ERR(req);
2019 		goto error;
2020 	}
2021 	err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
2022 	if (err) {
2023 		trace_9p_protocol_dump(clnt, &req->rc);
2024 		p9_tag_remove(clnt, req);
2025 		goto clunk_fid;
2026 	}
2027 	p9_tag_remove(clnt, req);
2028 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
2029 		attr_fid->fid, *attr_size);
2030 	return attr_fid;
2031 clunk_fid:
2032 	p9_client_clunk(attr_fid);
2033 	attr_fid = NULL;
2034 error:
2035 	if (attr_fid && (attr_fid != file_fid))
2036 		p9_fid_destroy(attr_fid);
2037 
2038 	return ERR_PTR(err);
2039 }
2040 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
2041 
2042 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
2043 			u64 attr_size, int flags)
2044 {
2045 	int err;
2046 	struct p9_req_t *req;
2047 	struct p9_client *clnt;
2048 
2049 	p9_debug(P9_DEBUG_9P,
2050 		">>> TXATTRCREATE fid %d name  %s size %lld flag %d\n",
2051 		fid->fid, name, (long long)attr_size, flags);
2052 	err = 0;
2053 	clnt = fid->clnt;
2054 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
2055 			fid->fid, name, attr_size, flags);
2056 	if (IS_ERR(req)) {
2057 		err = PTR_ERR(req);
2058 		goto error;
2059 	}
2060 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
2061 	p9_tag_remove(clnt, req);
2062 error:
2063 	return err;
2064 }
2065 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
2066 
2067 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
2068 {
2069 	int err, rsize, non_zc = 0;
2070 	struct p9_client *clnt;
2071 	struct p9_req_t *req;
2072 	char *dataptr;
2073 	struct kvec kv = {.iov_base = data, .iov_len = count};
2074 	struct iov_iter to;
2075 
2076 	iov_iter_kvec(&to, READ, &kv, 1, count);
2077 
2078 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
2079 				fid->fid, (unsigned long long) offset, count);
2080 
2081 	err = 0;
2082 	clnt = fid->clnt;
2083 
2084 	rsize = fid->iounit;
2085 	if (!rsize || rsize > clnt->msize-P9_READDIRHDRSZ)
2086 		rsize = clnt->msize - P9_READDIRHDRSZ;
2087 
2088 	if (count < rsize)
2089 		rsize = count;
2090 
2091 	/* Don't bother zerocopy for small IO (< 1024) */
2092 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2093 		/*
2094 		 * response header len is 11
2095 		 * PDU Header(7) + IO Size (4)
2096 		 */
2097 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2098 				       11, "dqd", fid->fid, offset, rsize);
2099 	} else {
2100 		non_zc = 1;
2101 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2102 				    offset, rsize);
2103 	}
2104 	if (IS_ERR(req)) {
2105 		err = PTR_ERR(req);
2106 		goto error;
2107 	}
2108 
2109 	err = p9pdu_readf(&req->rc, clnt->proto_version, "D", &count, &dataptr);
2110 	if (err) {
2111 		trace_9p_protocol_dump(clnt, &req->rc);
2112 		goto free_and_error;
2113 	}
2114 	if (rsize < count) {
2115 		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
2116 		count = rsize;
2117 	}
2118 
2119 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
2120 
2121 	if (non_zc)
2122 		memmove(data, dataptr, count);
2123 
2124 	p9_tag_remove(clnt, req);
2125 	return count;
2126 
2127 free_and_error:
2128 	p9_tag_remove(clnt, req);
2129 error:
2130 	return err;
2131 }
2132 EXPORT_SYMBOL(p9_client_readdir);
2133 
2134 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2135 			dev_t rdev, kgid_t gid, struct p9_qid *qid)
2136 {
2137 	int err;
2138 	struct p9_client *clnt;
2139 	struct p9_req_t *req;
2140 
2141 	err = 0;
2142 	clnt = fid->clnt;
2143 	p9_debug(P9_DEBUG_9P, ">>> TMKNOD fid %d name %s mode %d major %d "
2144 		"minor %d\n", fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2145 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2146 		MAJOR(rdev), MINOR(rdev), gid);
2147 	if (IS_ERR(req))
2148 		return PTR_ERR(req);
2149 
2150 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2151 	if (err) {
2152 		trace_9p_protocol_dump(clnt, &req->rc);
2153 		goto error;
2154 	}
2155 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n", qid->type,
2156 				(unsigned long long)qid->path, qid->version);
2157 
2158 error:
2159 	p9_tag_remove(clnt, req);
2160 	return err;
2161 
2162 }
2163 EXPORT_SYMBOL(p9_client_mknod_dotl);
2164 
2165 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2166 				kgid_t gid, struct p9_qid *qid)
2167 {
2168 	int err;
2169 	struct p9_client *clnt;
2170 	struct p9_req_t *req;
2171 
2172 	err = 0;
2173 	clnt = fid->clnt;
2174 	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
2175 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
2176 	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg", fid->fid, name, mode,
2177 		gid);
2178 	if (IS_ERR(req))
2179 		return PTR_ERR(req);
2180 
2181 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2182 	if (err) {
2183 		trace_9p_protocol_dump(clnt, &req->rc);
2184 		goto error;
2185 	}
2186 	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
2187 				(unsigned long long)qid->path, qid->version);
2188 
2189 error:
2190 	p9_tag_remove(clnt, req);
2191 	return err;
2192 
2193 }
2194 EXPORT_SYMBOL(p9_client_mkdir_dotl);
2195 
2196 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
2197 {
2198 	int err;
2199 	struct p9_client *clnt;
2200 	struct p9_req_t *req;
2201 
2202 	err = 0;
2203 	clnt = fid->clnt;
2204 	p9_debug(P9_DEBUG_9P, ">>> TLOCK fid %d type %i flags %d "
2205 			"start %lld length %lld proc_id %d client_id %s\n",
2206 			fid->fid, flock->type, flock->flags, flock->start,
2207 			flock->length, flock->proc_id, flock->client_id);
2208 
2209 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2210 				flock->flags, flock->start, flock->length,
2211 					flock->proc_id, flock->client_id);
2212 
2213 	if (IS_ERR(req))
2214 		return PTR_ERR(req);
2215 
2216 	err = p9pdu_readf(&req->rc, clnt->proto_version, "b", status);
2217 	if (err) {
2218 		trace_9p_protocol_dump(clnt, &req->rc);
2219 		goto error;
2220 	}
2221 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2222 error:
2223 	p9_tag_remove(clnt, req);
2224 	return err;
2225 
2226 }
2227 EXPORT_SYMBOL(p9_client_lock_dotl);
2228 
2229 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2230 {
2231 	int err;
2232 	struct p9_client *clnt;
2233 	struct p9_req_t *req;
2234 
2235 	err = 0;
2236 	clnt = fid->clnt;
2237 	p9_debug(P9_DEBUG_9P, ">>> TGETLOCK fid %d, type %i start %lld "
2238 		"length %lld proc_id %d client_id %s\n", fid->fid, glock->type,
2239 		glock->start, glock->length, glock->proc_id, glock->client_id);
2240 
2241 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,  glock->type,
2242 		glock->start, glock->length, glock->proc_id, glock->client_id);
2243 
2244 	if (IS_ERR(req))
2245 		return PTR_ERR(req);
2246 
2247 	err = p9pdu_readf(&req->rc, clnt->proto_version, "bqqds", &glock->type,
2248 			  &glock->start, &glock->length, &glock->proc_id,
2249 			  &glock->client_id);
2250 	if (err) {
2251 		trace_9p_protocol_dump(clnt, &req->rc);
2252 		goto error;
2253 	}
2254 	p9_debug(P9_DEBUG_9P, "<<< RGETLOCK type %i start %lld length %lld "
2255 		"proc_id %d client_id %s\n", glock->type, glock->start,
2256 		glock->length, glock->proc_id, glock->client_id);
2257 error:
2258 	p9_tag_remove(clnt, req);
2259 	return err;
2260 }
2261 EXPORT_SYMBOL(p9_client_getlock_dotl);
2262 
2263 int p9_client_readlink(struct p9_fid *fid, char **target)
2264 {
2265 	int err;
2266 	struct p9_client *clnt;
2267 	struct p9_req_t *req;
2268 
2269 	err = 0;
2270 	clnt = fid->clnt;
2271 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2272 
2273 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2274 	if (IS_ERR(req))
2275 		return PTR_ERR(req);
2276 
2277 	err = p9pdu_readf(&req->rc, clnt->proto_version, "s", target);
2278 	if (err) {
2279 		trace_9p_protocol_dump(clnt, &req->rc);
2280 		goto error;
2281 	}
2282 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2283 error:
2284 	p9_tag_remove(clnt, req);
2285 	return err;
2286 }
2287 EXPORT_SYMBOL(p9_client_readlink);
2288 
2289 int __init p9_client_init(void)
2290 {
2291 	p9_req_cache = KMEM_CACHE(p9_req_t, SLAB_TYPESAFE_BY_RCU);
2292 	return p9_req_cache ? 0 : -ENOMEM;
2293 }
2294 
2295 void __exit p9_client_exit(void)
2296 {
2297 	kmem_cache_destroy(p9_req_cache);
2298 }
2299