xref: /linux/net/9p/client.c (revision b48dbb998d70b7f48c2ec0a15c3cf47136808e4e)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * 9P Client
4  *
5  *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
6  *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
7  */
8 
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 
11 #include <linux/module.h>
12 #include <linux/errno.h>
13 #include <linux/fs.h>
14 #include <linux/poll.h>
15 #include <linux/idr.h>
16 #include <linux/mutex.h>
17 #include <linux/slab.h>
18 #include <linux/sched/signal.h>
19 #include <linux/uaccess.h>
20 #include <linux/uio.h>
21 #include <net/9p/9p.h>
22 #include <linux/parser.h>
23 #include <linux/seq_file.h>
24 #include <net/9p/client.h>
25 #include <net/9p/transport.h>
26 #include "protocol.h"
27 
28 #define CREATE_TRACE_POINTS
29 #include <trace/events/9p.h>
30 
31 #define DEFAULT_MSIZE (128 * 1024)
32 
33 /* Client Option Parsing (code inspired by NFS code)
34  *  - a little lazy - parse all client options
35  */
36 
37 enum {
38 	Opt_msize,
39 	Opt_trans,
40 	Opt_legacy,
41 	Opt_version,
42 	Opt_err,
43 };
44 
45 static const match_table_t tokens = {
46 	{Opt_msize, "msize=%u"},
47 	{Opt_legacy, "noextend"},
48 	{Opt_trans, "trans=%s"},
49 	{Opt_version, "version=%s"},
50 	{Opt_err, NULL},
51 };
52 
53 inline int p9_is_proto_dotl(struct p9_client *clnt)
54 {
55 	return clnt->proto_version == p9_proto_2000L;
56 }
57 EXPORT_SYMBOL(p9_is_proto_dotl);
58 
59 inline int p9_is_proto_dotu(struct p9_client *clnt)
60 {
61 	return clnt->proto_version == p9_proto_2000u;
62 }
63 EXPORT_SYMBOL(p9_is_proto_dotu);
64 
65 int p9_show_client_options(struct seq_file *m, struct p9_client *clnt)
66 {
67 	if (clnt->msize != DEFAULT_MSIZE)
68 		seq_printf(m, ",msize=%u", clnt->msize);
69 	seq_printf(m, ",trans=%s", clnt->trans_mod->name);
70 
71 	switch (clnt->proto_version) {
72 	case p9_proto_legacy:
73 		seq_puts(m, ",noextend");
74 		break;
75 	case p9_proto_2000u:
76 		seq_puts(m, ",version=9p2000.u");
77 		break;
78 	case p9_proto_2000L:
79 		/* Default */
80 		break;
81 	}
82 
83 	if (clnt->trans_mod->show_options)
84 		return clnt->trans_mod->show_options(m, clnt);
85 	return 0;
86 }
87 EXPORT_SYMBOL(p9_show_client_options);
88 
89 /* Some error codes are taken directly from the server replies,
90  * make sure they are valid.
91  */
92 static int safe_errno(int err)
93 {
94 	if (err > 0 || err < -MAX_ERRNO) {
95 		p9_debug(P9_DEBUG_ERROR, "Invalid error code %d\n", err);
96 		return -EPROTO;
97 	}
98 	return err;
99 }
100 
101 /* Interpret mount option for protocol version */
102 static int get_protocol_version(char *s)
103 {
104 	int version = -EINVAL;
105 
106 	if (!strcmp(s, "9p2000")) {
107 		version = p9_proto_legacy;
108 		p9_debug(P9_DEBUG_9P, "Protocol version: Legacy\n");
109 	} else if (!strcmp(s, "9p2000.u")) {
110 		version = p9_proto_2000u;
111 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.u\n");
112 	} else if (!strcmp(s, "9p2000.L")) {
113 		version = p9_proto_2000L;
114 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.L\n");
115 	} else {
116 		pr_info("Unknown protocol version %s\n", s);
117 	}
118 
119 	return version;
120 }
121 
122 /**
123  * parse_opts - parse mount options into client structure
124  * @opts: options string passed from mount
125  * @clnt: existing v9fs client information
126  *
127  * Return 0 upon success, -ERRNO upon failure
128  */
129 
130 static int parse_opts(char *opts, struct p9_client *clnt)
131 {
132 	char *options, *tmp_options;
133 	char *p;
134 	substring_t args[MAX_OPT_ARGS];
135 	int option;
136 	char *s;
137 	int ret = 0;
138 
139 	clnt->proto_version = p9_proto_2000L;
140 	clnt->msize = DEFAULT_MSIZE;
141 
142 	if (!opts)
143 		return 0;
144 
145 	tmp_options = kstrdup(opts, GFP_KERNEL);
146 	if (!tmp_options)
147 		return -ENOMEM;
148 	options = tmp_options;
149 
150 	while ((p = strsep(&options, ",")) != NULL) {
151 		int token, r;
152 
153 		if (!*p)
154 			continue;
155 		token = match_token(p, tokens, args);
156 		switch (token) {
157 		case Opt_msize:
158 			r = match_int(&args[0], &option);
159 			if (r < 0) {
160 				p9_debug(P9_DEBUG_ERROR,
161 					 "integer field, but no integer?\n");
162 				ret = r;
163 				continue;
164 			}
165 			if (option < 4096) {
166 				p9_debug(P9_DEBUG_ERROR,
167 					 "msize should be at least 4k\n");
168 				ret = -EINVAL;
169 				continue;
170 			}
171 			clnt->msize = option;
172 			break;
173 		case Opt_trans:
174 			s = match_strdup(&args[0]);
175 			if (!s) {
176 				ret = -ENOMEM;
177 				p9_debug(P9_DEBUG_ERROR,
178 					 "problem allocating copy of trans arg\n");
179 				goto free_and_return;
180 			}
181 
182 			v9fs_put_trans(clnt->trans_mod);
183 			clnt->trans_mod = v9fs_get_trans_by_name(s);
184 			if (!clnt->trans_mod) {
185 				pr_info("Could not find request transport: %s\n",
186 					s);
187 				ret = -EINVAL;
188 			}
189 			kfree(s);
190 			break;
191 		case Opt_legacy:
192 			clnt->proto_version = p9_proto_legacy;
193 			break;
194 		case Opt_version:
195 			s = match_strdup(&args[0]);
196 			if (!s) {
197 				ret = -ENOMEM;
198 				p9_debug(P9_DEBUG_ERROR,
199 					 "problem allocating copy of version arg\n");
200 				goto free_and_return;
201 			}
202 			r = get_protocol_version(s);
203 			if (r < 0)
204 				ret = r;
205 			else
206 				clnt->proto_version = r;
207 			kfree(s);
208 			break;
209 		default:
210 			continue;
211 		}
212 	}
213 
214 free_and_return:
215 	if (ret)
216 		v9fs_put_trans(clnt->trans_mod);
217 	kfree(tmp_options);
218 	return ret;
219 }
220 
221 static int p9_fcall_init(struct p9_client *c, struct p9_fcall *fc,
222 			 int alloc_msize)
223 {
224 	if (likely(c->fcall_cache) && alloc_msize == c->msize) {
225 		fc->sdata = kmem_cache_alloc(c->fcall_cache, GFP_NOFS);
226 		fc->cache = c->fcall_cache;
227 	} else {
228 		fc->sdata = kmalloc(alloc_msize, GFP_NOFS);
229 		fc->cache = NULL;
230 	}
231 	if (!fc->sdata)
232 		return -ENOMEM;
233 	fc->capacity = alloc_msize;
234 	return 0;
235 }
236 
237 void p9_fcall_fini(struct p9_fcall *fc)
238 {
239 	/* sdata can be NULL for interrupted requests in trans_rdma,
240 	 * and kmem_cache_free does not do NULL-check for us
241 	 */
242 	if (unlikely(!fc->sdata))
243 		return;
244 
245 	if (fc->cache)
246 		kmem_cache_free(fc->cache, fc->sdata);
247 	else
248 		kfree(fc->sdata);
249 }
250 EXPORT_SYMBOL(p9_fcall_fini);
251 
252 static struct kmem_cache *p9_req_cache;
253 
254 /**
255  * p9_tag_alloc - Allocate a new request.
256  * @c: Client session.
257  * @type: Transaction type.
258  * @max_size: Maximum packet size for this request.
259  *
260  * Context: Process context.
261  * Return: Pointer to new request.
262  */
263 static struct p9_req_t *
264 p9_tag_alloc(struct p9_client *c, int8_t type, unsigned int max_size)
265 {
266 	struct p9_req_t *req = kmem_cache_alloc(p9_req_cache, GFP_NOFS);
267 	int alloc_msize = min(c->msize, max_size);
268 	int tag;
269 
270 	if (!req)
271 		return ERR_PTR(-ENOMEM);
272 
273 	if (p9_fcall_init(c, &req->tc, alloc_msize))
274 		goto free_req;
275 	if (p9_fcall_init(c, &req->rc, alloc_msize))
276 		goto free;
277 
278 	p9pdu_reset(&req->tc);
279 	p9pdu_reset(&req->rc);
280 	req->t_err = 0;
281 	req->status = REQ_STATUS_ALLOC;
282 	init_waitqueue_head(&req->wq);
283 	INIT_LIST_HEAD(&req->req_list);
284 
285 	idr_preload(GFP_NOFS);
286 	spin_lock_irq(&c->lock);
287 	if (type == P9_TVERSION)
288 		tag = idr_alloc(&c->reqs, req, P9_NOTAG, P9_NOTAG + 1,
289 				GFP_NOWAIT);
290 	else
291 		tag = idr_alloc(&c->reqs, req, 0, P9_NOTAG, GFP_NOWAIT);
292 	req->tc.tag = tag;
293 	spin_unlock_irq(&c->lock);
294 	idr_preload_end();
295 	if (tag < 0)
296 		goto free;
297 
298 	/* Init ref to two because in the general case there is one ref
299 	 * that is put asynchronously by a writer thread, one ref
300 	 * temporarily given by p9_tag_lookup and put by p9_client_cb
301 	 * in the recv thread, and one ref put by p9_tag_remove in the
302 	 * main thread. The only exception is virtio that does not use
303 	 * p9_tag_lookup but does not have a writer thread either
304 	 * (the write happens synchronously in the request/zc_request
305 	 * callback), so p9_client_cb eats the second ref there
306 	 * as the pointer is duplicated directly by virtqueue_add_sgs()
307 	 */
308 	refcount_set(&req->refcount.refcount, 2);
309 
310 	return req;
311 
312 free:
313 	p9_fcall_fini(&req->tc);
314 	p9_fcall_fini(&req->rc);
315 free_req:
316 	kmem_cache_free(p9_req_cache, req);
317 	return ERR_PTR(-ENOMEM);
318 }
319 
320 /**
321  * p9_tag_lookup - Look up a request by tag.
322  * @c: Client session.
323  * @tag: Transaction ID.
324  *
325  * Context: Any context.
326  * Return: A request, or %NULL if there is no request with that tag.
327  */
328 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
329 {
330 	struct p9_req_t *req;
331 
332 	rcu_read_lock();
333 again:
334 	req = idr_find(&c->reqs, tag);
335 	if (req) {
336 		/* We have to be careful with the req found under rcu_read_lock
337 		 * Thanks to SLAB_TYPESAFE_BY_RCU we can safely try to get the
338 		 * ref again without corrupting other data, then check again
339 		 * that the tag matches once we have the ref
340 		 */
341 		if (!p9_req_try_get(req))
342 			goto again;
343 		if (req->tc.tag != tag) {
344 			p9_req_put(req);
345 			goto again;
346 		}
347 	}
348 	rcu_read_unlock();
349 
350 	return req;
351 }
352 EXPORT_SYMBOL(p9_tag_lookup);
353 
354 /**
355  * p9_tag_remove - Remove a tag.
356  * @c: Client session.
357  * @r: Request of reference.
358  *
359  * Context: Any context.
360  */
361 static int p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
362 {
363 	unsigned long flags;
364 	u16 tag = r->tc.tag;
365 
366 	p9_debug(P9_DEBUG_MUX, "clnt %p req %p tag: %d\n", c, r, tag);
367 	spin_lock_irqsave(&c->lock, flags);
368 	idr_remove(&c->reqs, tag);
369 	spin_unlock_irqrestore(&c->lock, flags);
370 	return p9_req_put(r);
371 }
372 
373 static void p9_req_free(struct kref *ref)
374 {
375 	struct p9_req_t *r = container_of(ref, struct p9_req_t, refcount);
376 
377 	p9_fcall_fini(&r->tc);
378 	p9_fcall_fini(&r->rc);
379 	kmem_cache_free(p9_req_cache, r);
380 }
381 
382 int p9_req_put(struct p9_req_t *r)
383 {
384 	return kref_put(&r->refcount, p9_req_free);
385 }
386 EXPORT_SYMBOL(p9_req_put);
387 
388 /**
389  * p9_tag_cleanup - cleans up tags structure and reclaims resources
390  * @c:  v9fs client struct
391  *
392  * This frees resources associated with the tags structure
393  *
394  */
395 static void p9_tag_cleanup(struct p9_client *c)
396 {
397 	struct p9_req_t *req;
398 	int id;
399 
400 	rcu_read_lock();
401 	idr_for_each_entry(&c->reqs, req, id) {
402 		pr_info("Tag %d still in use\n", id);
403 		if (p9_tag_remove(c, req) == 0)
404 			pr_warn("Packet with tag %d has still references",
405 				req->tc.tag);
406 	}
407 	rcu_read_unlock();
408 }
409 
410 /**
411  * p9_client_cb - call back from transport to client
412  * @c: client state
413  * @req: request received
414  * @status: request status, one of REQ_STATUS_*
415  *
416  */
417 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
418 {
419 	p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc.tag);
420 
421 	/* This barrier is needed to make sure any change made to req before
422 	 * the status change is visible to another thread
423 	 */
424 	smp_wmb();
425 	req->status = status;
426 
427 	wake_up(&req->wq);
428 	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
429 	p9_req_put(req);
430 }
431 EXPORT_SYMBOL(p9_client_cb);
432 
433 /**
434  * p9_parse_header - parse header arguments out of a packet
435  * @pdu: packet to parse
436  * @size: size of packet
437  * @type: type of request
438  * @tag: tag of packet
439  * @rewind: set if we need to rewind offset afterwards
440  */
441 
442 int
443 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type,
444 		int16_t *tag, int rewind)
445 {
446 	s8 r_type;
447 	s16 r_tag;
448 	s32 r_size;
449 	int offset = pdu->offset;
450 	int err;
451 
452 	pdu->offset = 0;
453 
454 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
455 	if (err)
456 		goto rewind_and_exit;
457 
458 	if (type)
459 		*type = r_type;
460 	if (tag)
461 		*tag = r_tag;
462 	if (size)
463 		*size = r_size;
464 
465 	if (pdu->size != r_size || r_size < 7) {
466 		err = -EINVAL;
467 		goto rewind_and_exit;
468 	}
469 
470 	pdu->id = r_type;
471 	pdu->tag = r_tag;
472 
473 	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
474 		 pdu->size, pdu->id, pdu->tag);
475 
476 rewind_and_exit:
477 	if (rewind)
478 		pdu->offset = offset;
479 	return err;
480 }
481 EXPORT_SYMBOL(p9_parse_header);
482 
483 /**
484  * p9_check_errors - check 9p packet for error return and process it
485  * @c: current client instance
486  * @req: request to parse and check for error conditions
487  *
488  * returns error code if one is discovered, otherwise returns 0
489  *
490  * this will have to be more complicated if we have multiple
491  * error packet types
492  */
493 
494 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
495 {
496 	s8 type;
497 	int err;
498 	int ecode;
499 
500 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
501 	if (req->rc.size >= c->msize) {
502 		p9_debug(P9_DEBUG_ERROR,
503 			 "requested packet size too big: %d\n",
504 			 req->rc.size);
505 		return -EIO;
506 	}
507 	/* dump the response from server
508 	 * This should be after check errors which poplulate pdu_fcall.
509 	 */
510 	trace_9p_protocol_dump(c, &req->rc);
511 	if (err) {
512 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
513 		return err;
514 	}
515 	if (type != P9_RERROR && type != P9_RLERROR)
516 		return 0;
517 
518 	if (!p9_is_proto_dotl(c)) {
519 		char *ename;
520 
521 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
522 				  &ename, &ecode);
523 		if (err)
524 			goto out_err;
525 
526 		if (p9_is_proto_dotu(c) && ecode < 512)
527 			err = -ecode;
528 
529 		if (!err) {
530 			err = p9_errstr2errno(ename, strlen(ename));
531 
532 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
533 				 -ecode, ename);
534 		}
535 		kfree(ename);
536 	} else {
537 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
538 		if (err)
539 			goto out_err;
540 		err = -ecode;
541 
542 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
543 	}
544 
545 	return err;
546 
547 out_err:
548 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
549 
550 	return err;
551 }
552 
553 /**
554  * p9_check_zc_errors - check 9p packet for error return and process it
555  * @c: current client instance
556  * @req: request to parse and check for error conditions
557  * @uidata: external buffer containing error
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 	s8 type;
572 	char *ename = NULL;
573 
574 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
575 	/* dump the response from server
576 	 * This should be after parse_header which poplulate pdu_fcall.
577 	 */
578 	trace_9p_protocol_dump(c, &req->rc);
579 	if (err) {
580 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
581 		return err;
582 	}
583 
584 	if (type != P9_RERROR && type != P9_RLERROR)
585 		return 0;
586 
587 	if (!p9_is_proto_dotl(c)) {
588 		/* Error is reported in string format */
589 		int len;
590 		/* 7 = header size for RERROR; */
591 		int inline_len = in_hdrlen - 7;
592 
593 		len = req->rc.size - req->rc.offset;
594 		if (len > (P9_ZC_HDR_SZ - 7)) {
595 			err = -EFAULT;
596 			goto out_err;
597 		}
598 
599 		ename = &req->rc.sdata[req->rc.offset];
600 		if (len > inline_len) {
601 			/* We have error in external buffer */
602 			if (!copy_from_iter_full(ename + inline_len,
603 						 len - inline_len, uidata)) {
604 				err = -EFAULT;
605 				goto out_err;
606 			}
607 		}
608 		ename = NULL;
609 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
610 				  &ename, &ecode);
611 		if (err)
612 			goto out_err;
613 
614 		if (p9_is_proto_dotu(c) && ecode < 512)
615 			err = -ecode;
616 
617 		if (!err) {
618 			err = p9_errstr2errno(ename, strlen(ename));
619 
620 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
621 				 -ecode, ename);
622 		}
623 		kfree(ename);
624 	} else {
625 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
626 		err = -ecode;
627 
628 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
629 	}
630 	return err;
631 
632 out_err:
633 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
634 	return err;
635 }
636 
637 static struct p9_req_t *
638 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
639 
640 /**
641  * p9_client_flush - flush (cancel) a request
642  * @c: client state
643  * @oldreq: request to cancel
644  *
645  * This sents a flush for a particular request and links
646  * the flush request to the original request.  The current
647  * code only supports a single flush request although the protocol
648  * allows for multiple flush requests to be sent for a single request.
649  *
650  */
651 
652 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
653 {
654 	struct p9_req_t *req;
655 	s16 oldtag;
656 	int err;
657 
658 	err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
659 	if (err)
660 		return err;
661 
662 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
663 
664 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
665 	if (IS_ERR(req))
666 		return PTR_ERR(req);
667 
668 	/* if we haven't received a response for oldreq,
669 	 * remove it from the list
670 	 */
671 	if (oldreq->status == REQ_STATUS_SENT) {
672 		if (c->trans_mod->cancelled)
673 			c->trans_mod->cancelled(c, oldreq);
674 	}
675 
676 	p9_tag_remove(c, req);
677 	return 0;
678 }
679 
680 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
681 					      int8_t type, int req_size,
682 					      const char *fmt, va_list ap)
683 {
684 	int err;
685 	struct p9_req_t *req;
686 
687 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
688 
689 	/* we allow for any status other than disconnected */
690 	if (c->status == Disconnected)
691 		return ERR_PTR(-EIO);
692 
693 	/* if status is begin_disconnected we allow only clunk request */
694 	if (c->status == BeginDisconnect && type != P9_TCLUNK)
695 		return ERR_PTR(-EIO);
696 
697 	req = p9_tag_alloc(c, type, req_size);
698 	if (IS_ERR(req))
699 		return req;
700 
701 	/* marshall the data */
702 	p9pdu_prepare(&req->tc, req->tc.tag, type);
703 	err = p9pdu_vwritef(&req->tc, c->proto_version, fmt, ap);
704 	if (err)
705 		goto reterr;
706 	p9pdu_finalize(c, &req->tc);
707 	trace_9p_client_req(c, type, req->tc.tag);
708 	return req;
709 reterr:
710 	p9_tag_remove(c, req);
711 	/* We have to put also the 2nd reference as it won't be used */
712 	p9_req_put(req);
713 	return ERR_PTR(err);
714 }
715 
716 /**
717  * p9_client_rpc - issue a request and wait for a response
718  * @c: client session
719  * @type: type of request
720  * @fmt: protocol format string (see protocol.c)
721  *
722  * Returns request structure (which client must free using p9_tag_remove)
723  */
724 
725 static struct p9_req_t *
726 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
727 {
728 	va_list ap;
729 	int sigpending, err;
730 	unsigned long flags;
731 	struct p9_req_t *req;
732 
733 	va_start(ap, fmt);
734 	req = p9_client_prepare_req(c, type, c->msize, fmt, ap);
735 	va_end(ap);
736 	if (IS_ERR(req))
737 		return req;
738 
739 	if (signal_pending(current)) {
740 		sigpending = 1;
741 		clear_thread_flag(TIF_SIGPENDING);
742 	} else {
743 		sigpending = 0;
744 	}
745 
746 	err = c->trans_mod->request(c, req);
747 	if (err < 0) {
748 		/* write won't happen */
749 		p9_req_put(req);
750 		if (err != -ERESTARTSYS && err != -EFAULT)
751 			c->status = Disconnected;
752 		goto recalc_sigpending;
753 	}
754 again:
755 	/* Wait for the response */
756 	err = wait_event_killable(req->wq, req->status >= REQ_STATUS_RCVD);
757 
758 	/* Make sure our req is coherent with regard to updates in other
759 	 * threads - echoes to wmb() in the callback
760 	 */
761 	smp_rmb();
762 
763 	if (err == -ERESTARTSYS && c->status == Connected &&
764 	    type == P9_TFLUSH) {
765 		sigpending = 1;
766 		clear_thread_flag(TIF_SIGPENDING);
767 		goto again;
768 	}
769 
770 	if (req->status == REQ_STATUS_ERROR) {
771 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
772 		err = req->t_err;
773 	}
774 	if (err == -ERESTARTSYS && c->status == Connected) {
775 		p9_debug(P9_DEBUG_MUX, "flushing\n");
776 		sigpending = 1;
777 		clear_thread_flag(TIF_SIGPENDING);
778 
779 		if (c->trans_mod->cancel(c, req))
780 			p9_client_flush(c, req);
781 
782 		/* if we received the response anyway, don't signal error */
783 		if (req->status == REQ_STATUS_RCVD)
784 			err = 0;
785 	}
786 recalc_sigpending:
787 	if (sigpending) {
788 		spin_lock_irqsave(&current->sighand->siglock, flags);
789 		recalc_sigpending();
790 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
791 	}
792 	if (err < 0)
793 		goto reterr;
794 
795 	err = p9_check_errors(c, req);
796 	trace_9p_client_res(c, type, req->rc.tag, err);
797 	if (!err)
798 		return req;
799 reterr:
800 	p9_tag_remove(c, req);
801 	return ERR_PTR(safe_errno(err));
802 }
803 
804 /**
805  * p9_client_zc_rpc - issue a request and wait for a response
806  * @c: client session
807  * @type: type of request
808  * @uidata: destination for zero copy read
809  * @uodata: source for zero copy write
810  * @inlen: read buffer size
811  * @olen: write buffer size
812  * @in_hdrlen: reader header size, This is the size of response protocol data
813  * @fmt: protocol format string (see protocol.c)
814  *
815  * Returns request structure (which client must free using p9_tag_remove)
816  */
817 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
818 					 struct iov_iter *uidata,
819 					 struct iov_iter *uodata,
820 					 int inlen, int olen, int in_hdrlen,
821 					 const char *fmt, ...)
822 {
823 	va_list ap;
824 	int sigpending, err;
825 	unsigned long flags;
826 	struct p9_req_t *req;
827 
828 	va_start(ap, fmt);
829 	/* We allocate a inline protocol data of only 4k bytes.
830 	 * The actual content is passed in zero-copy fashion.
831 	 */
832 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, fmt, ap);
833 	va_end(ap);
834 	if (IS_ERR(req))
835 		return req;
836 
837 	if (signal_pending(current)) {
838 		sigpending = 1;
839 		clear_thread_flag(TIF_SIGPENDING);
840 	} else {
841 		sigpending = 0;
842 	}
843 
844 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
845 				       inlen, olen, in_hdrlen);
846 	if (err < 0) {
847 		if (err == -EIO)
848 			c->status = Disconnected;
849 		if (err != -ERESTARTSYS)
850 			goto recalc_sigpending;
851 	}
852 	if (req->status == REQ_STATUS_ERROR) {
853 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
854 		err = req->t_err;
855 	}
856 	if (err == -ERESTARTSYS && c->status == Connected) {
857 		p9_debug(P9_DEBUG_MUX, "flushing\n");
858 		sigpending = 1;
859 		clear_thread_flag(TIF_SIGPENDING);
860 
861 		if (c->trans_mod->cancel(c, req))
862 			p9_client_flush(c, req);
863 
864 		/* if we received the response anyway, don't signal error */
865 		if (req->status == REQ_STATUS_RCVD)
866 			err = 0;
867 	}
868 recalc_sigpending:
869 	if (sigpending) {
870 		spin_lock_irqsave(&current->sighand->siglock, flags);
871 		recalc_sigpending();
872 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
873 	}
874 	if (err < 0)
875 		goto reterr;
876 
877 	err = p9_check_zc_errors(c, req, uidata, in_hdrlen);
878 	trace_9p_client_res(c, type, req->rc.tag, err);
879 	if (!err)
880 		return req;
881 reterr:
882 	p9_tag_remove(c, req);
883 	return ERR_PTR(safe_errno(err));
884 }
885 
886 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
887 {
888 	int ret;
889 	struct p9_fid *fid;
890 
891 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
892 	fid = kmalloc(sizeof(*fid), GFP_KERNEL);
893 	if (!fid)
894 		return NULL;
895 
896 	memset(&fid->qid, 0, sizeof(fid->qid));
897 	fid->mode = -1;
898 	fid->uid = current_fsuid();
899 	fid->clnt = clnt;
900 	fid->rdir = NULL;
901 	fid->fid = 0;
902 	refcount_set(&fid->count, 1);
903 
904 	idr_preload(GFP_KERNEL);
905 	spin_lock_irq(&clnt->lock);
906 	ret = idr_alloc_u32(&clnt->fids, fid, &fid->fid, P9_NOFID - 1,
907 			    GFP_NOWAIT);
908 	spin_unlock_irq(&clnt->lock);
909 	idr_preload_end();
910 	if (!ret)
911 		return fid;
912 
913 	kfree(fid);
914 	return NULL;
915 }
916 
917 static void p9_fid_destroy(struct p9_fid *fid)
918 {
919 	struct p9_client *clnt;
920 	unsigned long flags;
921 
922 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
923 	clnt = fid->clnt;
924 	spin_lock_irqsave(&clnt->lock, flags);
925 	idr_remove(&clnt->fids, fid->fid);
926 	spin_unlock_irqrestore(&clnt->lock, flags);
927 	kfree(fid->rdir);
928 	kfree(fid);
929 }
930 
931 static int p9_client_version(struct p9_client *c)
932 {
933 	int err = 0;
934 	struct p9_req_t *req;
935 	char *version = NULL;
936 	int msize;
937 
938 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
939 		 c->msize, c->proto_version);
940 
941 	switch (c->proto_version) {
942 	case p9_proto_2000L:
943 		req = p9_client_rpc(c, P9_TVERSION, "ds",
944 				    c->msize, "9P2000.L");
945 		break;
946 	case p9_proto_2000u:
947 		req = p9_client_rpc(c, P9_TVERSION, "ds",
948 				    c->msize, "9P2000.u");
949 		break;
950 	case p9_proto_legacy:
951 		req = p9_client_rpc(c, P9_TVERSION, "ds",
952 				    c->msize, "9P2000");
953 		break;
954 	default:
955 		return -EINVAL;
956 	}
957 
958 	if (IS_ERR(req))
959 		return PTR_ERR(req);
960 
961 	err = p9pdu_readf(&req->rc, c->proto_version, "ds", &msize, &version);
962 	if (err) {
963 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
964 		trace_9p_protocol_dump(c, &req->rc);
965 		goto error;
966 	}
967 
968 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
969 	if (!strncmp(version, "9P2000.L", 8)) {
970 		c->proto_version = p9_proto_2000L;
971 	} else if (!strncmp(version, "9P2000.u", 8)) {
972 		c->proto_version = p9_proto_2000u;
973 	} else if (!strncmp(version, "9P2000", 6)) {
974 		c->proto_version = p9_proto_legacy;
975 	} else {
976 		p9_debug(P9_DEBUG_ERROR,
977 			 "server returned an unknown version: %s\n", version);
978 		err = -EREMOTEIO;
979 		goto error;
980 	}
981 
982 	if (msize < 4096) {
983 		p9_debug(P9_DEBUG_ERROR,
984 			 "server returned a msize < 4096: %d\n", msize);
985 		err = -EREMOTEIO;
986 		goto error;
987 	}
988 	if (msize < c->msize)
989 		c->msize = msize;
990 
991 error:
992 	kfree(version);
993 	p9_tag_remove(c, req);
994 
995 	return err;
996 }
997 
998 struct p9_client *p9_client_create(const char *dev_name, char *options)
999 {
1000 	int err;
1001 	struct p9_client *clnt;
1002 	char *client_id;
1003 
1004 	err = 0;
1005 	clnt = kmalloc(sizeof(*clnt), GFP_KERNEL);
1006 	if (!clnt)
1007 		return ERR_PTR(-ENOMEM);
1008 
1009 	clnt->trans_mod = NULL;
1010 	clnt->trans = NULL;
1011 	clnt->fcall_cache = NULL;
1012 
1013 	client_id = utsname()->nodename;
1014 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
1015 
1016 	spin_lock_init(&clnt->lock);
1017 	idr_init(&clnt->fids);
1018 	idr_init(&clnt->reqs);
1019 
1020 	err = parse_opts(options, clnt);
1021 	if (err < 0)
1022 		goto free_client;
1023 
1024 	if (!clnt->trans_mod)
1025 		clnt->trans_mod = v9fs_get_default_trans();
1026 
1027 	if (!clnt->trans_mod) {
1028 		err = -EPROTONOSUPPORT;
1029 		p9_debug(P9_DEBUG_ERROR,
1030 			 "No transport defined or default transport\n");
1031 		goto free_client;
1032 	}
1033 
1034 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
1035 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
1036 
1037 	err = clnt->trans_mod->create(clnt, dev_name, options);
1038 	if (err)
1039 		goto put_trans;
1040 
1041 	if (clnt->msize > clnt->trans_mod->maxsize) {
1042 		clnt->msize = clnt->trans_mod->maxsize;
1043 		pr_info("Limiting 'msize' to %d as this is the maximum "
1044 			"supported by transport %s\n",
1045 			clnt->msize, clnt->trans_mod->name
1046 		);
1047 	}
1048 
1049 	if (clnt->msize < 4096) {
1050 		p9_debug(P9_DEBUG_ERROR,
1051 			 "Please specify a msize of at least 4k\n");
1052 		err = -EINVAL;
1053 		goto close_trans;
1054 	}
1055 
1056 	err = p9_client_version(clnt);
1057 	if (err)
1058 		goto close_trans;
1059 
1060 	/* P9_HDRSZ + 4 is the smallest packet header we can have that is
1061 	 * followed by data accessed from userspace by read
1062 	 */
1063 	clnt->fcall_cache =
1064 		kmem_cache_create_usercopy("9p-fcall-cache", clnt->msize,
1065 					   0, 0, P9_HDRSZ + 4,
1066 					   clnt->msize - (P9_HDRSZ + 4),
1067 					   NULL);
1068 
1069 	return clnt;
1070 
1071 close_trans:
1072 	clnt->trans_mod->close(clnt);
1073 put_trans:
1074 	v9fs_put_trans(clnt->trans_mod);
1075 free_client:
1076 	kfree(clnt);
1077 	return ERR_PTR(err);
1078 }
1079 EXPORT_SYMBOL(p9_client_create);
1080 
1081 void p9_client_destroy(struct p9_client *clnt)
1082 {
1083 	struct p9_fid *fid;
1084 	int id;
1085 
1086 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1087 
1088 	if (clnt->trans_mod)
1089 		clnt->trans_mod->close(clnt);
1090 
1091 	v9fs_put_trans(clnt->trans_mod);
1092 
1093 	idr_for_each_entry(&clnt->fids, fid, id) {
1094 		pr_info("Found fid %d not clunked\n", fid->fid);
1095 		p9_fid_destroy(fid);
1096 	}
1097 
1098 	p9_tag_cleanup(clnt);
1099 
1100 	kmem_cache_destroy(clnt->fcall_cache);
1101 	kfree(clnt);
1102 }
1103 EXPORT_SYMBOL(p9_client_destroy);
1104 
1105 void p9_client_disconnect(struct p9_client *clnt)
1106 {
1107 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1108 	clnt->status = Disconnected;
1109 }
1110 EXPORT_SYMBOL(p9_client_disconnect);
1111 
1112 void p9_client_begin_disconnect(struct p9_client *clnt)
1113 {
1114 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1115 	clnt->status = BeginDisconnect;
1116 }
1117 EXPORT_SYMBOL(p9_client_begin_disconnect);
1118 
1119 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1120 				const char *uname, kuid_t n_uname,
1121 				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 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1129 		 afid ? afid->fid : -1, uname, aname);
1130 	fid = p9_fid_create(clnt);
1131 	if (!fid) {
1132 		err = -ENOMEM;
1133 		goto error;
1134 	}
1135 	fid->uid = n_uname;
1136 
1137 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
1138 			    afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
1139 	if (IS_ERR(req)) {
1140 		err = PTR_ERR(req);
1141 		goto error;
1142 	}
1143 
1144 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", &qid);
1145 	if (err) {
1146 		trace_9p_protocol_dump(clnt, &req->rc);
1147 		p9_tag_remove(clnt, req);
1148 		goto error;
1149 	}
1150 
1151 	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
1152 		 qid.type, qid.path, qid.version);
1153 
1154 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1155 
1156 	p9_tag_remove(clnt, req);
1157 	return fid;
1158 
1159 error:
1160 	if (fid)
1161 		p9_fid_destroy(fid);
1162 	return ERR_PTR(err);
1163 }
1164 EXPORT_SYMBOL(p9_client_attach);
1165 
1166 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
1167 			      const unsigned char * const *wnames, int clone)
1168 {
1169 	int err;
1170 	struct p9_client *clnt;
1171 	struct p9_fid *fid;
1172 	struct p9_qid *wqids;
1173 	struct p9_req_t *req;
1174 	u16 nwqids, count;
1175 
1176 	err = 0;
1177 	wqids = NULL;
1178 	clnt = oldfid->clnt;
1179 	if (clone) {
1180 		fid = p9_fid_create(clnt);
1181 		if (!fid) {
1182 			err = -ENOMEM;
1183 			goto error;
1184 		}
1185 
1186 		fid->uid = oldfid->uid;
1187 	} else {
1188 		fid = oldfid;
1189 	}
1190 
1191 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1192 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1193 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1194 			    nwname, wnames);
1195 	if (IS_ERR(req)) {
1196 		err = PTR_ERR(req);
1197 		goto error;
1198 	}
1199 
1200 	err = p9pdu_readf(&req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1201 	if (err) {
1202 		trace_9p_protocol_dump(clnt, &req->rc);
1203 		p9_tag_remove(clnt, req);
1204 		goto clunk_fid;
1205 	}
1206 	p9_tag_remove(clnt, req);
1207 
1208 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1209 
1210 	if (nwqids != nwname) {
1211 		err = -ENOENT;
1212 		goto clunk_fid;
1213 	}
1214 
1215 	for (count = 0; count < nwqids; count++)
1216 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1217 			 count, wqids[count].type,
1218 			 wqids[count].path,
1219 			 wqids[count].version);
1220 
1221 	if (nwname)
1222 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1223 	else
1224 		memmove(&fid->qid, &oldfid->qid, sizeof(struct p9_qid));
1225 
1226 	kfree(wqids);
1227 	return fid;
1228 
1229 clunk_fid:
1230 	kfree(wqids);
1231 	p9_fid_put(fid);
1232 	fid = NULL;
1233 
1234 error:
1235 	if (fid && fid != oldfid)
1236 		p9_fid_destroy(fid);
1237 
1238 	return ERR_PTR(err);
1239 }
1240 EXPORT_SYMBOL(p9_client_walk);
1241 
1242 int p9_client_open(struct p9_fid *fid, int mode)
1243 {
1244 	int err;
1245 	struct p9_client *clnt;
1246 	struct p9_req_t *req;
1247 	struct p9_qid qid;
1248 	int iounit;
1249 
1250 	clnt = fid->clnt;
1251 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1252 		 p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1253 	err = 0;
1254 
1255 	if (fid->mode != -1)
1256 		return -EINVAL;
1257 
1258 	if (p9_is_proto_dotl(clnt))
1259 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode);
1260 	else
1261 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
1262 	if (IS_ERR(req)) {
1263 		err = PTR_ERR(req);
1264 		goto error;
1265 	}
1266 
1267 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1268 	if (err) {
1269 		trace_9p_protocol_dump(clnt, &req->rc);
1270 		goto free_and_error;
1271 	}
1272 
1273 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1274 		 p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1275 		 qid.path, qid.version, iounit);
1276 
1277 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1278 	fid->mode = mode;
1279 	fid->iounit = iounit;
1280 
1281 free_and_error:
1282 	p9_tag_remove(clnt, req);
1283 error:
1284 	return err;
1285 }
1286 EXPORT_SYMBOL(p9_client_open);
1287 
1288 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags,
1289 			  u32 mode, kgid_t gid, struct p9_qid *qid)
1290 {
1291 	int err = 0;
1292 	struct p9_client *clnt;
1293 	struct p9_req_t *req;
1294 	int iounit;
1295 
1296 	p9_debug(P9_DEBUG_9P,
1297 		 ">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1298 		 ofid->fid, name, flags, mode,
1299 		 from_kgid(&init_user_ns, gid));
1300 	clnt = ofid->clnt;
1301 
1302 	if (ofid->mode != -1)
1303 		return -EINVAL;
1304 
1305 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1306 			    mode, gid);
1307 	if (IS_ERR(req)) {
1308 		err = PTR_ERR(req);
1309 		goto error;
1310 	}
1311 
1312 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", qid, &iounit);
1313 	if (err) {
1314 		trace_9p_protocol_dump(clnt, &req->rc);
1315 		goto free_and_error;
1316 	}
1317 
1318 	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1319 		 qid->type, qid->path, qid->version, iounit);
1320 
1321 	memmove(&ofid->qid, qid, sizeof(struct p9_qid));
1322 	ofid->mode = mode;
1323 	ofid->iounit = iounit;
1324 
1325 free_and_error:
1326 	p9_tag_remove(clnt, req);
1327 error:
1328 	return err;
1329 }
1330 EXPORT_SYMBOL(p9_client_create_dotl);
1331 
1332 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1333 		     char *extension)
1334 {
1335 	int err;
1336 	struct p9_client *clnt;
1337 	struct p9_req_t *req;
1338 	struct p9_qid qid;
1339 	int iounit;
1340 
1341 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1342 		 fid->fid, name, perm, mode);
1343 	err = 0;
1344 	clnt = fid->clnt;
1345 
1346 	if (fid->mode != -1)
1347 		return -EINVAL;
1348 
1349 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1350 			    mode, extension);
1351 	if (IS_ERR(req)) {
1352 		err = PTR_ERR(req);
1353 		goto error;
1354 	}
1355 
1356 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1357 	if (err) {
1358 		trace_9p_protocol_dump(clnt, &req->rc);
1359 		goto free_and_error;
1360 	}
1361 
1362 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1363 		 qid.type, qid.path, qid.version, iounit);
1364 
1365 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1366 	fid->mode = mode;
1367 	fid->iounit = iounit;
1368 
1369 free_and_error:
1370 	p9_tag_remove(clnt, req);
1371 error:
1372 	return err;
1373 }
1374 EXPORT_SYMBOL(p9_client_fcreate);
1375 
1376 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1377 		      const char *symtgt, kgid_t gid, struct p9_qid *qid)
1378 {
1379 	int err = 0;
1380 	struct p9_client *clnt;
1381 	struct p9_req_t *req;
1382 
1383 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1384 		 dfid->fid, name, symtgt);
1385 	clnt = dfid->clnt;
1386 
1387 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1388 			    gid);
1389 	if (IS_ERR(req)) {
1390 		err = PTR_ERR(req);
1391 		goto error;
1392 	}
1393 
1394 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
1395 	if (err) {
1396 		trace_9p_protocol_dump(clnt, &req->rc);
1397 		goto free_and_error;
1398 	}
1399 
1400 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1401 		 qid->type, qid->path, qid->version);
1402 
1403 free_and_error:
1404 	p9_tag_remove(clnt, req);
1405 error:
1406 	return err;
1407 }
1408 EXPORT_SYMBOL(p9_client_symlink);
1409 
1410 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1411 {
1412 	struct p9_client *clnt;
1413 	struct p9_req_t *req;
1414 
1415 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1416 		 dfid->fid, oldfid->fid, newname);
1417 	clnt = dfid->clnt;
1418 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1419 			    newname);
1420 	if (IS_ERR(req))
1421 		return PTR_ERR(req);
1422 
1423 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1424 	p9_tag_remove(clnt, req);
1425 	return 0;
1426 }
1427 EXPORT_SYMBOL(p9_client_link);
1428 
1429 int p9_client_fsync(struct p9_fid *fid, int datasync)
1430 {
1431 	int err;
1432 	struct p9_client *clnt;
1433 	struct p9_req_t *req;
1434 
1435 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1436 		 fid->fid, datasync);
1437 	err = 0;
1438 	clnt = fid->clnt;
1439 
1440 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1441 	if (IS_ERR(req)) {
1442 		err = PTR_ERR(req);
1443 		goto error;
1444 	}
1445 
1446 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1447 
1448 	p9_tag_remove(clnt, req);
1449 
1450 error:
1451 	return err;
1452 }
1453 EXPORT_SYMBOL(p9_client_fsync);
1454 
1455 int p9_client_clunk(struct p9_fid *fid)
1456 {
1457 	int err;
1458 	struct p9_client *clnt;
1459 	struct p9_req_t *req;
1460 	int retries = 0;
1461 
1462 again:
1463 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n",
1464 		 fid->fid, retries);
1465 	err = 0;
1466 	clnt = fid->clnt;
1467 
1468 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1469 	if (IS_ERR(req)) {
1470 		err = PTR_ERR(req);
1471 		goto error;
1472 	}
1473 
1474 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1475 
1476 	p9_tag_remove(clnt, req);
1477 error:
1478 	/* Fid is not valid even after a failed clunk
1479 	 * If interrupted, retry once then give up and
1480 	 * leak fid until umount.
1481 	 */
1482 	if (err == -ERESTARTSYS) {
1483 		if (retries++ == 0)
1484 			goto again;
1485 	} else {
1486 		p9_fid_destroy(fid);
1487 	}
1488 	return err;
1489 }
1490 EXPORT_SYMBOL(p9_client_clunk);
1491 
1492 int p9_client_remove(struct p9_fid *fid)
1493 {
1494 	int err;
1495 	struct p9_client *clnt;
1496 	struct p9_req_t *req;
1497 
1498 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1499 	err = 0;
1500 	clnt = fid->clnt;
1501 
1502 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1503 	if (IS_ERR(req)) {
1504 		err = PTR_ERR(req);
1505 		goto error;
1506 	}
1507 
1508 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1509 
1510 	p9_tag_remove(clnt, req);
1511 error:
1512 	if (err == -ERESTARTSYS)
1513 		p9_fid_put(fid);
1514 	else
1515 		p9_fid_destroy(fid);
1516 	return err;
1517 }
1518 EXPORT_SYMBOL(p9_client_remove);
1519 
1520 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1521 {
1522 	int err = 0;
1523 	struct p9_req_t *req;
1524 	struct p9_client *clnt;
1525 
1526 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1527 		 dfid->fid, name, flags);
1528 
1529 	clnt = dfid->clnt;
1530 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1531 	if (IS_ERR(req)) {
1532 		err = PTR_ERR(req);
1533 		goto error;
1534 	}
1535 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1536 
1537 	p9_tag_remove(clnt, req);
1538 error:
1539 	return err;
1540 }
1541 EXPORT_SYMBOL(p9_client_unlinkat);
1542 
1543 int
1544 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1545 {
1546 	int total = 0;
1547 	*err = 0;
1548 
1549 	while (iov_iter_count(to)) {
1550 		int count;
1551 
1552 		count = p9_client_read_once(fid, offset, to, err);
1553 		if (!count || *err)
1554 			break;
1555 		offset += count;
1556 		total += count;
1557 	}
1558 	return total;
1559 }
1560 EXPORT_SYMBOL(p9_client_read);
1561 
1562 int
1563 p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
1564 		    int *err)
1565 {
1566 	struct p9_client *clnt = fid->clnt;
1567 	struct p9_req_t *req;
1568 	int count = iov_iter_count(to);
1569 	int rsize, non_zc = 0;
1570 	char *dataptr;
1571 
1572 	*err = 0;
1573 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %zu\n",
1574 		 fid->fid, offset, iov_iter_count(to));
1575 
1576 	rsize = fid->iounit;
1577 	if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1578 		rsize = clnt->msize - P9_IOHDRSZ;
1579 
1580 	if (count < rsize)
1581 		rsize = count;
1582 
1583 	/* Don't bother zerocopy for small IO (< 1024) */
1584 	if (clnt->trans_mod->zc_request && rsize > 1024) {
1585 		/* response header len is 11
1586 		 * PDU Header(7) + IO Size (4)
1587 		 */
1588 		req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1589 				       0, 11, "dqd", fid->fid,
1590 				       offset, rsize);
1591 	} else {
1592 		non_zc = 1;
1593 		req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1594 				    rsize);
1595 	}
1596 	if (IS_ERR(req)) {
1597 		*err = PTR_ERR(req);
1598 		return 0;
1599 	}
1600 
1601 	*err = p9pdu_readf(&req->rc, clnt->proto_version,
1602 			   "D", &count, &dataptr);
1603 	if (*err) {
1604 		trace_9p_protocol_dump(clnt, &req->rc);
1605 		p9_tag_remove(clnt, req);
1606 		return 0;
1607 	}
1608 	if (rsize < count) {
1609 		pr_err("bogus RREAD count (%d > %d)\n", count, rsize);
1610 		count = rsize;
1611 	}
1612 
1613 	p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1614 
1615 	if (non_zc) {
1616 		int n = copy_to_iter(dataptr, count, to);
1617 
1618 		if (n != count) {
1619 			*err = -EFAULT;
1620 			p9_tag_remove(clnt, req);
1621 			return n;
1622 		}
1623 	} else {
1624 		iov_iter_advance(to, count);
1625 	}
1626 	p9_tag_remove(clnt, req);
1627 	return count;
1628 }
1629 EXPORT_SYMBOL(p9_client_read_once);
1630 
1631 int
1632 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1633 {
1634 	struct p9_client *clnt = fid->clnt;
1635 	struct p9_req_t *req;
1636 	int total = 0;
1637 	*err = 0;
1638 
1639 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n",
1640 		 fid->fid, offset, iov_iter_count(from));
1641 
1642 	while (iov_iter_count(from)) {
1643 		int count = iov_iter_count(from);
1644 		int rsize = fid->iounit;
1645 
1646 		if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1647 			rsize = clnt->msize - P9_IOHDRSZ;
1648 
1649 		if (count < rsize)
1650 			rsize = count;
1651 
1652 		/* Don't bother zerocopy for small IO (< 1024) */
1653 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1654 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1655 					       rsize, P9_ZC_HDR_SZ, "dqd",
1656 					       fid->fid, offset, rsize);
1657 		} else {
1658 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1659 					    offset, rsize, from);
1660 		}
1661 		if (IS_ERR(req)) {
1662 			*err = PTR_ERR(req);
1663 			break;
1664 		}
1665 
1666 		*err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &count);
1667 		if (*err) {
1668 			trace_9p_protocol_dump(clnt, &req->rc);
1669 			p9_tag_remove(clnt, req);
1670 			break;
1671 		}
1672 		if (rsize < count) {
1673 			pr_err("bogus RWRITE count (%d > %d)\n", count, rsize);
1674 			count = rsize;
1675 		}
1676 
1677 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1678 
1679 		p9_tag_remove(clnt, req);
1680 		iov_iter_advance(from, count);
1681 		total += count;
1682 		offset += count;
1683 	}
1684 	return total;
1685 }
1686 EXPORT_SYMBOL(p9_client_write);
1687 
1688 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1689 {
1690 	int err;
1691 	struct p9_client *clnt;
1692 	struct p9_wstat *ret;
1693 	struct p9_req_t *req;
1694 	u16 ignored;
1695 
1696 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1697 
1698 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1699 	if (!ret)
1700 		return ERR_PTR(-ENOMEM);
1701 
1702 	err = 0;
1703 	clnt = fid->clnt;
1704 
1705 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1706 	if (IS_ERR(req)) {
1707 		err = PTR_ERR(req);
1708 		goto error;
1709 	}
1710 
1711 	err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
1712 	if (err) {
1713 		trace_9p_protocol_dump(clnt, &req->rc);
1714 		p9_tag_remove(clnt, req);
1715 		goto error;
1716 	}
1717 
1718 	p9_debug(P9_DEBUG_9P,
1719 		 "<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1720 		 "<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1721 		 "<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1722 		 "<<<    uid=%d gid=%d n_muid=%d\n",
1723 		 ret->size, ret->type, ret->dev, ret->qid.type, ret->qid.path,
1724 		 ret->qid.version, ret->mode,
1725 		 ret->atime, ret->mtime, ret->length,
1726 		 ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1727 		 from_kuid(&init_user_ns, ret->n_uid),
1728 		 from_kgid(&init_user_ns, ret->n_gid),
1729 		 from_kuid(&init_user_ns, ret->n_muid));
1730 
1731 	p9_tag_remove(clnt, req);
1732 	return ret;
1733 
1734 error:
1735 	kfree(ret);
1736 	return ERR_PTR(err);
1737 }
1738 EXPORT_SYMBOL(p9_client_stat);
1739 
1740 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1741 					    u64 request_mask)
1742 {
1743 	int err;
1744 	struct p9_client *clnt;
1745 	struct p9_stat_dotl *ret;
1746 	struct p9_req_t *req;
1747 
1748 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1749 		 fid->fid, request_mask);
1750 
1751 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1752 	if (!ret)
1753 		return ERR_PTR(-ENOMEM);
1754 
1755 	err = 0;
1756 	clnt = fid->clnt;
1757 
1758 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1759 	if (IS_ERR(req)) {
1760 		err = PTR_ERR(req);
1761 		goto error;
1762 	}
1763 
1764 	err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
1765 	if (err) {
1766 		trace_9p_protocol_dump(clnt, &req->rc);
1767 		p9_tag_remove(clnt, req);
1768 		goto error;
1769 	}
1770 
1771 	p9_debug(P9_DEBUG_9P, "<<< RGETATTR st_result_mask=%lld\n"
1772 		 "<<< qid=%x.%llx.%x\n"
1773 		 "<<< st_mode=%8.8x st_nlink=%llu\n"
1774 		 "<<< st_uid=%d st_gid=%d\n"
1775 		 "<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1776 		 "<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1777 		 "<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1778 		 "<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1779 		 "<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1780 		 "<<< st_gen=%lld st_data_version=%lld\n",
1781 		 ret->st_result_mask,
1782 		 ret->qid.type, ret->qid.path, ret->qid.version,
1783 		 ret->st_mode, ret->st_nlink,
1784 		 from_kuid(&init_user_ns, ret->st_uid),
1785 		 from_kgid(&init_user_ns, ret->st_gid),
1786 		 ret->st_rdev, ret->st_size, ret->st_blksize, ret->st_blocks,
1787 		 ret->st_atime_sec, ret->st_atime_nsec,
1788 		 ret->st_mtime_sec, ret->st_mtime_nsec,
1789 		 ret->st_ctime_sec, ret->st_ctime_nsec,
1790 		 ret->st_btime_sec, ret->st_btime_nsec,
1791 		 ret->st_gen, ret->st_data_version);
1792 
1793 	p9_tag_remove(clnt, req);
1794 	return ret;
1795 
1796 error:
1797 	kfree(ret);
1798 	return ERR_PTR(err);
1799 }
1800 EXPORT_SYMBOL(p9_client_getattr_dotl);
1801 
1802 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1803 {
1804 	int ret;
1805 
1806 	/* NOTE: size shouldn't include its own length */
1807 	/* size[2] type[2] dev[4] qid[13] */
1808 	/* mode[4] atime[4] mtime[4] length[8]*/
1809 	/* name[s] uid[s] gid[s] muid[s] */
1810 	ret = 2 + 4 + 13 + 4 + 4 + 4 + 8 + 2 + 2 + 2 + 2;
1811 
1812 	if (wst->name)
1813 		ret += strlen(wst->name);
1814 	if (wst->uid)
1815 		ret += strlen(wst->uid);
1816 	if (wst->gid)
1817 		ret += strlen(wst->gid);
1818 	if (wst->muid)
1819 		ret += strlen(wst->muid);
1820 
1821 	if (proto_version == p9_proto_2000u ||
1822 	    proto_version == p9_proto_2000L) {
1823 		/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1824 		ret += 2 + 4 + 4 + 4;
1825 		if (wst->extension)
1826 			ret += strlen(wst->extension);
1827 	}
1828 
1829 	return ret;
1830 }
1831 
1832 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1833 {
1834 	int err;
1835 	struct p9_req_t *req;
1836 	struct p9_client *clnt;
1837 
1838 	err = 0;
1839 	clnt = fid->clnt;
1840 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1841 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n",
1842 		 fid->fid);
1843 	p9_debug(P9_DEBUG_9P,
1844 		 "     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1845 		 "     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1846 		 "     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1847 		 "     uid=%d gid=%d n_muid=%d\n",
1848 		 wst->size, wst->type, wst->dev, wst->qid.type,
1849 		 wst->qid.path, wst->qid.version,
1850 		 wst->mode, wst->atime, wst->mtime, wst->length,
1851 		 wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1852 		 from_kuid(&init_user_ns, wst->n_uid),
1853 		 from_kgid(&init_user_ns, wst->n_gid),
1854 		 from_kuid(&init_user_ns, wst->n_muid));
1855 
1856 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS",
1857 			    fid->fid, wst->size + 2, wst);
1858 	if (IS_ERR(req)) {
1859 		err = PTR_ERR(req);
1860 		goto error;
1861 	}
1862 
1863 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1864 
1865 	p9_tag_remove(clnt, req);
1866 error:
1867 	return err;
1868 }
1869 EXPORT_SYMBOL(p9_client_wstat);
1870 
1871 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1872 {
1873 	int err;
1874 	struct p9_req_t *req;
1875 	struct p9_client *clnt;
1876 
1877 	err = 0;
1878 	clnt = fid->clnt;
1879 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1880 	p9_debug(P9_DEBUG_9P, "    valid=%x mode=%x uid=%d gid=%d size=%lld\n",
1881 		 p9attr->valid, p9attr->mode,
1882 		 from_kuid(&init_user_ns, p9attr->uid),
1883 		 from_kgid(&init_user_ns, p9attr->gid),
1884 		 p9attr->size);
1885 	p9_debug(P9_DEBUG_9P, "    atime_sec=%lld atime_nsec=%lld\n",
1886 		 p9attr->atime_sec, p9attr->atime_nsec);
1887 	p9_debug(P9_DEBUG_9P, "    mtime_sec=%lld mtime_nsec=%lld\n",
1888 		 p9attr->mtime_sec, p9attr->mtime_nsec);
1889 
1890 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1891 
1892 	if (IS_ERR(req)) {
1893 		err = PTR_ERR(req);
1894 		goto error;
1895 	}
1896 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1897 	p9_tag_remove(clnt, req);
1898 error:
1899 	return err;
1900 }
1901 EXPORT_SYMBOL(p9_client_setattr);
1902 
1903 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1904 {
1905 	int err;
1906 	struct p9_req_t *req;
1907 	struct p9_client *clnt;
1908 
1909 	err = 0;
1910 	clnt = fid->clnt;
1911 
1912 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1913 
1914 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1915 	if (IS_ERR(req)) {
1916 		err = PTR_ERR(req);
1917 		goto error;
1918 	}
1919 
1920 	err = p9pdu_readf(&req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1921 			  &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1922 			  &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1923 	if (err) {
1924 		trace_9p_protocol_dump(clnt, &req->rc);
1925 		p9_tag_remove(clnt, req);
1926 		goto error;
1927 	}
1928 
1929 	p9_debug(P9_DEBUG_9P,
1930 		 "<<< RSTATFS fid %d type 0x%x bsize %u blocks %llu bfree %llu bavail %llu files %llu ffree %llu fsid %llu namelen %u\n",
1931 		 fid->fid, sb->type, sb->bsize, sb->blocks, sb->bfree,
1932 		 sb->bavail, sb->files, sb->ffree, sb->fsid, sb->namelen);
1933 
1934 	p9_tag_remove(clnt, req);
1935 error:
1936 	return err;
1937 }
1938 EXPORT_SYMBOL(p9_client_statfs);
1939 
1940 int p9_client_rename(struct p9_fid *fid,
1941 		     struct p9_fid *newdirfid, const char *name)
1942 {
1943 	int err;
1944 	struct p9_req_t *req;
1945 	struct p9_client *clnt;
1946 
1947 	err = 0;
1948 	clnt = fid->clnt;
1949 
1950 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1951 		 fid->fid, newdirfid->fid, name);
1952 
1953 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1954 			    newdirfid->fid, name);
1955 	if (IS_ERR(req)) {
1956 		err = PTR_ERR(req);
1957 		goto error;
1958 	}
1959 
1960 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1961 
1962 	p9_tag_remove(clnt, req);
1963 error:
1964 	return err;
1965 }
1966 EXPORT_SYMBOL(p9_client_rename);
1967 
1968 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
1969 		       struct p9_fid *newdirfid, const char *new_name)
1970 {
1971 	int err;
1972 	struct p9_req_t *req;
1973 	struct p9_client *clnt;
1974 
1975 	err = 0;
1976 	clnt = olddirfid->clnt;
1977 
1978 	p9_debug(P9_DEBUG_9P,
1979 		 ">>> TRENAMEAT olddirfid %d old name %s newdirfid %d new name %s\n",
1980 		 olddirfid->fid, old_name, newdirfid->fid, new_name);
1981 
1982 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
1983 			    old_name, newdirfid->fid, new_name);
1984 	if (IS_ERR(req)) {
1985 		err = PTR_ERR(req);
1986 		goto error;
1987 	}
1988 
1989 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
1990 		 newdirfid->fid, new_name);
1991 
1992 	p9_tag_remove(clnt, req);
1993 error:
1994 	return err;
1995 }
1996 EXPORT_SYMBOL(p9_client_renameat);
1997 
1998 /* An xattrwalk without @attr_name gives the fid for the lisxattr namespace
1999  */
2000 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
2001 				   const char *attr_name, u64 *attr_size)
2002 {
2003 	int err;
2004 	struct p9_req_t *req;
2005 	struct p9_client *clnt;
2006 	struct p9_fid *attr_fid;
2007 
2008 	err = 0;
2009 	clnt = file_fid->clnt;
2010 	attr_fid = p9_fid_create(clnt);
2011 	if (!attr_fid) {
2012 		err = -ENOMEM;
2013 		goto error;
2014 	}
2015 	p9_debug(P9_DEBUG_9P,
2016 		 ">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
2017 		 file_fid->fid, attr_fid->fid, attr_name);
2018 
2019 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
2020 			    file_fid->fid, attr_fid->fid, attr_name);
2021 	if (IS_ERR(req)) {
2022 		err = PTR_ERR(req);
2023 		goto error;
2024 	}
2025 	err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
2026 	if (err) {
2027 		trace_9p_protocol_dump(clnt, &req->rc);
2028 		p9_tag_remove(clnt, req);
2029 		goto clunk_fid;
2030 	}
2031 	p9_tag_remove(clnt, req);
2032 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
2033 		 attr_fid->fid, *attr_size);
2034 	return attr_fid;
2035 clunk_fid:
2036 	p9_fid_put(attr_fid);
2037 	attr_fid = NULL;
2038 error:
2039 	if (attr_fid && attr_fid != file_fid)
2040 		p9_fid_destroy(attr_fid);
2041 
2042 	return ERR_PTR(err);
2043 }
2044 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
2045 
2046 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
2047 			  u64 attr_size, int flags)
2048 {
2049 	int err;
2050 	struct p9_req_t *req;
2051 	struct p9_client *clnt;
2052 
2053 	p9_debug(P9_DEBUG_9P,
2054 		 ">>> TXATTRCREATE fid %d name  %s size %llu flag %d\n",
2055 		 fid->fid, name, attr_size, flags);
2056 	err = 0;
2057 	clnt = fid->clnt;
2058 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
2059 			    fid->fid, name, attr_size, flags);
2060 	if (IS_ERR(req)) {
2061 		err = PTR_ERR(req);
2062 		goto error;
2063 	}
2064 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
2065 	p9_tag_remove(clnt, req);
2066 error:
2067 	return err;
2068 }
2069 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
2070 
2071 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
2072 {
2073 	int err, rsize, non_zc = 0;
2074 	struct p9_client *clnt;
2075 	struct p9_req_t *req;
2076 	char *dataptr;
2077 	struct kvec kv = {.iov_base = data, .iov_len = count};
2078 	struct iov_iter to;
2079 
2080 	iov_iter_kvec(&to, READ, &kv, 1, count);
2081 
2082 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
2083 		 fid->fid, offset, count);
2084 
2085 	err = 0;
2086 	clnt = fid->clnt;
2087 
2088 	rsize = fid->iounit;
2089 	if (!rsize || rsize > clnt->msize - P9_READDIRHDRSZ)
2090 		rsize = clnt->msize - P9_READDIRHDRSZ;
2091 
2092 	if (count < rsize)
2093 		rsize = count;
2094 
2095 	/* Don't bother zerocopy for small IO (< 1024) */
2096 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2097 		/* response header len is 11
2098 		 * PDU Header(7) + IO Size (4)
2099 		 */
2100 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2101 				       11, "dqd", fid->fid, offset, rsize);
2102 	} else {
2103 		non_zc = 1;
2104 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2105 				    offset, rsize);
2106 	}
2107 	if (IS_ERR(req)) {
2108 		err = PTR_ERR(req);
2109 		goto error;
2110 	}
2111 
2112 	err = p9pdu_readf(&req->rc, clnt->proto_version, "D", &count, &dataptr);
2113 	if (err) {
2114 		trace_9p_protocol_dump(clnt, &req->rc);
2115 		goto free_and_error;
2116 	}
2117 	if (rsize < count) {
2118 		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
2119 		count = rsize;
2120 	}
2121 
2122 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
2123 
2124 	if (non_zc)
2125 		memmove(data, dataptr, count);
2126 
2127 	p9_tag_remove(clnt, req);
2128 	return count;
2129 
2130 free_and_error:
2131 	p9_tag_remove(clnt, req);
2132 error:
2133 	return err;
2134 }
2135 EXPORT_SYMBOL(p9_client_readdir);
2136 
2137 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2138 			 dev_t rdev, kgid_t gid, struct p9_qid *qid)
2139 {
2140 	int err;
2141 	struct p9_client *clnt;
2142 	struct p9_req_t *req;
2143 
2144 	err = 0;
2145 	clnt = fid->clnt;
2146 	p9_debug(P9_DEBUG_9P,
2147 		 ">>> TMKNOD fid %d name %s mode %d major %d minor %d\n",
2148 		 fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2149 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2150 			    MAJOR(rdev), MINOR(rdev), gid);
2151 	if (IS_ERR(req))
2152 		return PTR_ERR(req);
2153 
2154 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2155 	if (err) {
2156 		trace_9p_protocol_dump(clnt, &req->rc);
2157 		goto error;
2158 	}
2159 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n",
2160 		 qid->type, qid->path, qid->version);
2161 
2162 error:
2163 	p9_tag_remove(clnt, req);
2164 	return err;
2165 }
2166 EXPORT_SYMBOL(p9_client_mknod_dotl);
2167 
2168 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2169 			 kgid_t gid, struct p9_qid *qid)
2170 {
2171 	int err;
2172 	struct p9_client *clnt;
2173 	struct p9_req_t *req;
2174 
2175 	err = 0;
2176 	clnt = fid->clnt;
2177 	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
2178 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
2179 	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg",
2180 			    fid->fid, name, mode, gid);
2181 	if (IS_ERR(req))
2182 		return PTR_ERR(req);
2183 
2184 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2185 	if (err) {
2186 		trace_9p_protocol_dump(clnt, &req->rc);
2187 		goto error;
2188 	}
2189 	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
2190 		 qid->path, qid->version);
2191 
2192 error:
2193 	p9_tag_remove(clnt, req);
2194 	return err;
2195 }
2196 EXPORT_SYMBOL(p9_client_mkdir_dotl);
2197 
2198 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
2199 {
2200 	int err;
2201 	struct p9_client *clnt;
2202 	struct p9_req_t *req;
2203 
2204 	err = 0;
2205 	clnt = fid->clnt;
2206 	p9_debug(P9_DEBUG_9P,
2207 		 ">>> TLOCK fid %d type %i flags %d start %lld length %lld proc_id %d client_id %s\n",
2208 		 fid->fid, flock->type, flock->flags, flock->start,
2209 		 flock->length, flock->proc_id, flock->client_id);
2210 
2211 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2212 			    flock->flags, flock->start, flock->length,
2213 			    flock->proc_id, flock->client_id);
2214 
2215 	if (IS_ERR(req))
2216 		return PTR_ERR(req);
2217 
2218 	err = p9pdu_readf(&req->rc, clnt->proto_version, "b", status);
2219 	if (err) {
2220 		trace_9p_protocol_dump(clnt, &req->rc);
2221 		goto error;
2222 	}
2223 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2224 error:
2225 	p9_tag_remove(clnt, req);
2226 	return err;
2227 }
2228 EXPORT_SYMBOL(p9_client_lock_dotl);
2229 
2230 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2231 {
2232 	int err;
2233 	struct p9_client *clnt;
2234 	struct p9_req_t *req;
2235 
2236 	err = 0;
2237 	clnt = fid->clnt;
2238 	p9_debug(P9_DEBUG_9P,
2239 		 ">>> TGETLOCK fid %d, type %i start %lld length %lld proc_id %d client_id %s\n",
2240 		 fid->fid, glock->type, glock->start, glock->length,
2241 		 glock->proc_id, glock->client_id);
2242 
2243 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,
2244 			    glock->type, glock->start, glock->length,
2245 			    glock->proc_id, glock->client_id);
2246 
2247 	if (IS_ERR(req))
2248 		return PTR_ERR(req);
2249 
2250 	err = p9pdu_readf(&req->rc, clnt->proto_version, "bqqds", &glock->type,
2251 			  &glock->start, &glock->length, &glock->proc_id,
2252 			  &glock->client_id);
2253 	if (err) {
2254 		trace_9p_protocol_dump(clnt, &req->rc);
2255 		goto error;
2256 	}
2257 	p9_debug(P9_DEBUG_9P,
2258 		 "<<< RGETLOCK type %i start %lld length %lld proc_id %d client_id %s\n",
2259 		 glock->type, glock->start, glock->length,
2260 		 glock->proc_id, glock->client_id);
2261 error:
2262 	p9_tag_remove(clnt, req);
2263 	return err;
2264 }
2265 EXPORT_SYMBOL(p9_client_getlock_dotl);
2266 
2267 int p9_client_readlink(struct p9_fid *fid, char **target)
2268 {
2269 	int err;
2270 	struct p9_client *clnt;
2271 	struct p9_req_t *req;
2272 
2273 	err = 0;
2274 	clnt = fid->clnt;
2275 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2276 
2277 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2278 	if (IS_ERR(req))
2279 		return PTR_ERR(req);
2280 
2281 	err = p9pdu_readf(&req->rc, clnt->proto_version, "s", target);
2282 	if (err) {
2283 		trace_9p_protocol_dump(clnt, &req->rc);
2284 		goto error;
2285 	}
2286 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2287 error:
2288 	p9_tag_remove(clnt, req);
2289 	return err;
2290 }
2291 EXPORT_SYMBOL(p9_client_readlink);
2292 
2293 int __init p9_client_init(void)
2294 {
2295 	p9_req_cache = KMEM_CACHE(p9_req_t, SLAB_TYPESAFE_BY_RCU);
2296 	return p9_req_cache ? 0 : -ENOMEM;
2297 }
2298 
2299 void __exit p9_client_exit(void)
2300 {
2301 	kmem_cache_destroy(p9_req_cache);
2302 }
2303