xref: /openbmc/linux/net/9p/client.c (revision 6614a3c3164a5df2b54abb0b3559f51041cf705b)
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 static struct p9_req_t *
554 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
555 
556 /**
557  * p9_client_flush - flush (cancel) a request
558  * @c: client state
559  * @oldreq: request to cancel
560  *
561  * This sents a flush for a particular request and links
562  * the flush request to the original request.  The current
563  * code only supports a single flush request although the protocol
564  * allows for multiple flush requests to be sent for a single request.
565  *
566  */
567 
568 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
569 {
570 	struct p9_req_t *req;
571 	s16 oldtag;
572 	int err;
573 
574 	err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
575 	if (err)
576 		return err;
577 
578 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
579 
580 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
581 	if (IS_ERR(req))
582 		return PTR_ERR(req);
583 
584 	/* if we haven't received a response for oldreq,
585 	 * remove it from the list
586 	 */
587 	if (oldreq->status == REQ_STATUS_SENT) {
588 		if (c->trans_mod->cancelled)
589 			c->trans_mod->cancelled(c, oldreq);
590 	}
591 
592 	p9_tag_remove(c, req);
593 	return 0;
594 }
595 
596 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
597 					      int8_t type, int req_size,
598 					      const char *fmt, va_list ap)
599 {
600 	int err;
601 	struct p9_req_t *req;
602 
603 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
604 
605 	/* we allow for any status other than disconnected */
606 	if (c->status == Disconnected)
607 		return ERR_PTR(-EIO);
608 
609 	/* if status is begin_disconnected we allow only clunk request */
610 	if (c->status == BeginDisconnect && type != P9_TCLUNK)
611 		return ERR_PTR(-EIO);
612 
613 	req = p9_tag_alloc(c, type, req_size);
614 	if (IS_ERR(req))
615 		return req;
616 
617 	/* marshall the data */
618 	p9pdu_prepare(&req->tc, req->tc.tag, type);
619 	err = p9pdu_vwritef(&req->tc, c->proto_version, fmt, ap);
620 	if (err)
621 		goto reterr;
622 	p9pdu_finalize(c, &req->tc);
623 	trace_9p_client_req(c, type, req->tc.tag);
624 	return req;
625 reterr:
626 	p9_tag_remove(c, req);
627 	/* We have to put also the 2nd reference as it won't be used */
628 	p9_req_put(req);
629 	return ERR_PTR(err);
630 }
631 
632 /**
633  * p9_client_rpc - issue a request and wait for a response
634  * @c: client session
635  * @type: type of request
636  * @fmt: protocol format string (see protocol.c)
637  *
638  * Returns request structure (which client must free using p9_tag_remove)
639  */
640 
641 static struct p9_req_t *
642 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
643 {
644 	va_list ap;
645 	int sigpending, err;
646 	unsigned long flags;
647 	struct p9_req_t *req;
648 
649 	va_start(ap, fmt);
650 	req = p9_client_prepare_req(c, type, c->msize, fmt, ap);
651 	va_end(ap);
652 	if (IS_ERR(req))
653 		return req;
654 
655 	if (signal_pending(current)) {
656 		sigpending = 1;
657 		clear_thread_flag(TIF_SIGPENDING);
658 	} else {
659 		sigpending = 0;
660 	}
661 
662 	err = c->trans_mod->request(c, req);
663 	if (err < 0) {
664 		/* write won't happen */
665 		p9_req_put(req);
666 		if (err != -ERESTARTSYS && err != -EFAULT)
667 			c->status = Disconnected;
668 		goto recalc_sigpending;
669 	}
670 again:
671 	/* Wait for the response */
672 	err = wait_event_killable(req->wq, req->status >= REQ_STATUS_RCVD);
673 
674 	/* Make sure our req is coherent with regard to updates in other
675 	 * threads - echoes to wmb() in the callback
676 	 */
677 	smp_rmb();
678 
679 	if (err == -ERESTARTSYS && c->status == Connected &&
680 	    type == P9_TFLUSH) {
681 		sigpending = 1;
682 		clear_thread_flag(TIF_SIGPENDING);
683 		goto again;
684 	}
685 
686 	if (req->status == REQ_STATUS_ERROR) {
687 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
688 		err = req->t_err;
689 	}
690 	if (err == -ERESTARTSYS && c->status == Connected) {
691 		p9_debug(P9_DEBUG_MUX, "flushing\n");
692 		sigpending = 1;
693 		clear_thread_flag(TIF_SIGPENDING);
694 
695 		if (c->trans_mod->cancel(c, req))
696 			p9_client_flush(c, req);
697 
698 		/* if we received the response anyway, don't signal error */
699 		if (req->status == REQ_STATUS_RCVD)
700 			err = 0;
701 	}
702 recalc_sigpending:
703 	if (sigpending) {
704 		spin_lock_irqsave(&current->sighand->siglock, flags);
705 		recalc_sigpending();
706 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
707 	}
708 	if (err < 0)
709 		goto reterr;
710 
711 	err = p9_check_errors(c, req);
712 	trace_9p_client_res(c, type, req->rc.tag, err);
713 	if (!err)
714 		return req;
715 reterr:
716 	p9_tag_remove(c, req);
717 	return ERR_PTR(safe_errno(err));
718 }
719 
720 /**
721  * p9_client_zc_rpc - issue a request and wait for a response
722  * @c: client session
723  * @type: type of request
724  * @uidata: destination for zero copy read
725  * @uodata: source for zero copy write
726  * @inlen: read buffer size
727  * @olen: write buffer size
728  * @in_hdrlen: reader header size, This is the size of response protocol data
729  * @fmt: protocol format string (see protocol.c)
730  *
731  * Returns request structure (which client must free using p9_tag_remove)
732  */
733 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
734 					 struct iov_iter *uidata,
735 					 struct iov_iter *uodata,
736 					 int inlen, int olen, int in_hdrlen,
737 					 const char *fmt, ...)
738 {
739 	va_list ap;
740 	int sigpending, err;
741 	unsigned long flags;
742 	struct p9_req_t *req;
743 
744 	va_start(ap, fmt);
745 	/* We allocate a inline protocol data of only 4k bytes.
746 	 * The actual content is passed in zero-copy fashion.
747 	 */
748 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, fmt, ap);
749 	va_end(ap);
750 	if (IS_ERR(req))
751 		return req;
752 
753 	if (signal_pending(current)) {
754 		sigpending = 1;
755 		clear_thread_flag(TIF_SIGPENDING);
756 	} else {
757 		sigpending = 0;
758 	}
759 
760 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
761 				       inlen, olen, in_hdrlen);
762 	if (err < 0) {
763 		if (err == -EIO)
764 			c->status = Disconnected;
765 		if (err != -ERESTARTSYS)
766 			goto recalc_sigpending;
767 	}
768 	if (req->status == REQ_STATUS_ERROR) {
769 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
770 		err = req->t_err;
771 	}
772 	if (err == -ERESTARTSYS && c->status == Connected) {
773 		p9_debug(P9_DEBUG_MUX, "flushing\n");
774 		sigpending = 1;
775 		clear_thread_flag(TIF_SIGPENDING);
776 
777 		if (c->trans_mod->cancel(c, req))
778 			p9_client_flush(c, req);
779 
780 		/* if we received the response anyway, don't signal error */
781 		if (req->status == REQ_STATUS_RCVD)
782 			err = 0;
783 	}
784 recalc_sigpending:
785 	if (sigpending) {
786 		spin_lock_irqsave(&current->sighand->siglock, flags);
787 		recalc_sigpending();
788 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
789 	}
790 	if (err < 0)
791 		goto reterr;
792 
793 	err = p9_check_errors(c, req);
794 	trace_9p_client_res(c, type, req->rc.tag, err);
795 	if (!err)
796 		return req;
797 reterr:
798 	p9_tag_remove(c, req);
799 	return ERR_PTR(safe_errno(err));
800 }
801 
802 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
803 {
804 	int ret;
805 	struct p9_fid *fid;
806 
807 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
808 	fid = kmalloc(sizeof(*fid), GFP_KERNEL);
809 	if (!fid)
810 		return NULL;
811 
812 	memset(&fid->qid, 0, sizeof(fid->qid));
813 	fid->mode = -1;
814 	fid->uid = current_fsuid();
815 	fid->clnt = clnt;
816 	fid->rdir = NULL;
817 	fid->fid = 0;
818 	refcount_set(&fid->count, 1);
819 
820 	idr_preload(GFP_KERNEL);
821 	spin_lock_irq(&clnt->lock);
822 	ret = idr_alloc_u32(&clnt->fids, fid, &fid->fid, P9_NOFID - 1,
823 			    GFP_NOWAIT);
824 	spin_unlock_irq(&clnt->lock);
825 	idr_preload_end();
826 	if (!ret)
827 		return fid;
828 
829 	kfree(fid);
830 	return NULL;
831 }
832 
833 static void p9_fid_destroy(struct p9_fid *fid)
834 {
835 	struct p9_client *clnt;
836 	unsigned long flags;
837 
838 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
839 	clnt = fid->clnt;
840 	spin_lock_irqsave(&clnt->lock, flags);
841 	idr_remove(&clnt->fids, fid->fid);
842 	spin_unlock_irqrestore(&clnt->lock, flags);
843 	kfree(fid->rdir);
844 	kfree(fid);
845 }
846 
847 static int p9_client_version(struct p9_client *c)
848 {
849 	int err = 0;
850 	struct p9_req_t *req;
851 	char *version = NULL;
852 	int msize;
853 
854 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
855 		 c->msize, c->proto_version);
856 
857 	switch (c->proto_version) {
858 	case p9_proto_2000L:
859 		req = p9_client_rpc(c, P9_TVERSION, "ds",
860 				    c->msize, "9P2000.L");
861 		break;
862 	case p9_proto_2000u:
863 		req = p9_client_rpc(c, P9_TVERSION, "ds",
864 				    c->msize, "9P2000.u");
865 		break;
866 	case p9_proto_legacy:
867 		req = p9_client_rpc(c, P9_TVERSION, "ds",
868 				    c->msize, "9P2000");
869 		break;
870 	default:
871 		return -EINVAL;
872 	}
873 
874 	if (IS_ERR(req))
875 		return PTR_ERR(req);
876 
877 	err = p9pdu_readf(&req->rc, c->proto_version, "ds", &msize, &version);
878 	if (err) {
879 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
880 		trace_9p_protocol_dump(c, &req->rc);
881 		goto error;
882 	}
883 
884 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
885 	if (!strncmp(version, "9P2000.L", 8)) {
886 		c->proto_version = p9_proto_2000L;
887 	} else if (!strncmp(version, "9P2000.u", 8)) {
888 		c->proto_version = p9_proto_2000u;
889 	} else if (!strncmp(version, "9P2000", 6)) {
890 		c->proto_version = p9_proto_legacy;
891 	} else {
892 		p9_debug(P9_DEBUG_ERROR,
893 			 "server returned an unknown version: %s\n", version);
894 		err = -EREMOTEIO;
895 		goto error;
896 	}
897 
898 	if (msize < 4096) {
899 		p9_debug(P9_DEBUG_ERROR,
900 			 "server returned a msize < 4096: %d\n", msize);
901 		err = -EREMOTEIO;
902 		goto error;
903 	}
904 	if (msize < c->msize)
905 		c->msize = msize;
906 
907 error:
908 	kfree(version);
909 	p9_tag_remove(c, req);
910 
911 	return err;
912 }
913 
914 struct p9_client *p9_client_create(const char *dev_name, char *options)
915 {
916 	int err;
917 	struct p9_client *clnt;
918 	char *client_id;
919 
920 	err = 0;
921 	clnt = kmalloc(sizeof(*clnt), GFP_KERNEL);
922 	if (!clnt)
923 		return ERR_PTR(-ENOMEM);
924 
925 	clnt->trans_mod = NULL;
926 	clnt->trans = NULL;
927 	clnt->fcall_cache = NULL;
928 
929 	client_id = utsname()->nodename;
930 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
931 
932 	spin_lock_init(&clnt->lock);
933 	idr_init(&clnt->fids);
934 	idr_init(&clnt->reqs);
935 
936 	err = parse_opts(options, clnt);
937 	if (err < 0)
938 		goto free_client;
939 
940 	if (!clnt->trans_mod)
941 		clnt->trans_mod = v9fs_get_default_trans();
942 
943 	if (!clnt->trans_mod) {
944 		err = -EPROTONOSUPPORT;
945 		p9_debug(P9_DEBUG_ERROR,
946 			 "No transport defined or default transport\n");
947 		goto free_client;
948 	}
949 
950 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
951 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
952 
953 	err = clnt->trans_mod->create(clnt, dev_name, options);
954 	if (err)
955 		goto put_trans;
956 
957 	if (clnt->msize > clnt->trans_mod->maxsize) {
958 		clnt->msize = clnt->trans_mod->maxsize;
959 		pr_info("Limiting 'msize' to %d as this is the maximum "
960 			"supported by transport %s\n",
961 			clnt->msize, clnt->trans_mod->name
962 		);
963 	}
964 
965 	if (clnt->msize < 4096) {
966 		p9_debug(P9_DEBUG_ERROR,
967 			 "Please specify a msize of at least 4k\n");
968 		err = -EINVAL;
969 		goto close_trans;
970 	}
971 
972 	err = p9_client_version(clnt);
973 	if (err)
974 		goto close_trans;
975 
976 	/* P9_HDRSZ + 4 is the smallest packet header we can have that is
977 	 * followed by data accessed from userspace by read
978 	 */
979 	clnt->fcall_cache =
980 		kmem_cache_create_usercopy("9p-fcall-cache", clnt->msize,
981 					   0, 0, P9_HDRSZ + 4,
982 					   clnt->msize - (P9_HDRSZ + 4),
983 					   NULL);
984 
985 	return clnt;
986 
987 close_trans:
988 	clnt->trans_mod->close(clnt);
989 put_trans:
990 	v9fs_put_trans(clnt->trans_mod);
991 free_client:
992 	kfree(clnt);
993 	return ERR_PTR(err);
994 }
995 EXPORT_SYMBOL(p9_client_create);
996 
997 void p9_client_destroy(struct p9_client *clnt)
998 {
999 	struct p9_fid *fid;
1000 	int id;
1001 
1002 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1003 
1004 	if (clnt->trans_mod)
1005 		clnt->trans_mod->close(clnt);
1006 
1007 	v9fs_put_trans(clnt->trans_mod);
1008 
1009 	idr_for_each_entry(&clnt->fids, fid, id) {
1010 		pr_info("Found fid %d not clunked\n", fid->fid);
1011 		p9_fid_destroy(fid);
1012 	}
1013 
1014 	p9_tag_cleanup(clnt);
1015 
1016 	kmem_cache_destroy(clnt->fcall_cache);
1017 	kfree(clnt);
1018 }
1019 EXPORT_SYMBOL(p9_client_destroy);
1020 
1021 void p9_client_disconnect(struct p9_client *clnt)
1022 {
1023 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1024 	clnt->status = Disconnected;
1025 }
1026 EXPORT_SYMBOL(p9_client_disconnect);
1027 
1028 void p9_client_begin_disconnect(struct p9_client *clnt)
1029 {
1030 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1031 	clnt->status = BeginDisconnect;
1032 }
1033 EXPORT_SYMBOL(p9_client_begin_disconnect);
1034 
1035 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1036 				const char *uname, kuid_t n_uname,
1037 				const char *aname)
1038 {
1039 	int err = 0;
1040 	struct p9_req_t *req;
1041 	struct p9_fid *fid;
1042 	struct p9_qid qid;
1043 
1044 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1045 		 afid ? afid->fid : -1, uname, aname);
1046 	fid = p9_fid_create(clnt);
1047 	if (!fid) {
1048 		err = -ENOMEM;
1049 		goto error;
1050 	}
1051 	fid->uid = n_uname;
1052 
1053 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
1054 			    afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
1055 	if (IS_ERR(req)) {
1056 		err = PTR_ERR(req);
1057 		goto error;
1058 	}
1059 
1060 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", &qid);
1061 	if (err) {
1062 		trace_9p_protocol_dump(clnt, &req->rc);
1063 		p9_tag_remove(clnt, req);
1064 		goto error;
1065 	}
1066 
1067 	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
1068 		 qid.type, qid.path, qid.version);
1069 
1070 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1071 
1072 	p9_tag_remove(clnt, req);
1073 	return fid;
1074 
1075 error:
1076 	if (fid)
1077 		p9_fid_destroy(fid);
1078 	return ERR_PTR(err);
1079 }
1080 EXPORT_SYMBOL(p9_client_attach);
1081 
1082 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
1083 			      const unsigned char * const *wnames, int clone)
1084 {
1085 	int err;
1086 	struct p9_client *clnt;
1087 	struct p9_fid *fid;
1088 	struct p9_qid *wqids;
1089 	struct p9_req_t *req;
1090 	u16 nwqids, count;
1091 
1092 	err = 0;
1093 	wqids = NULL;
1094 	clnt = oldfid->clnt;
1095 	if (clone) {
1096 		fid = p9_fid_create(clnt);
1097 		if (!fid) {
1098 			err = -ENOMEM;
1099 			goto error;
1100 		}
1101 
1102 		fid->uid = oldfid->uid;
1103 	} else {
1104 		fid = oldfid;
1105 	}
1106 
1107 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1108 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1109 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1110 			    nwname, wnames);
1111 	if (IS_ERR(req)) {
1112 		err = PTR_ERR(req);
1113 		goto error;
1114 	}
1115 
1116 	err = p9pdu_readf(&req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1117 	if (err) {
1118 		trace_9p_protocol_dump(clnt, &req->rc);
1119 		p9_tag_remove(clnt, req);
1120 		goto clunk_fid;
1121 	}
1122 	p9_tag_remove(clnt, req);
1123 
1124 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1125 
1126 	if (nwqids != nwname) {
1127 		err = -ENOENT;
1128 		goto clunk_fid;
1129 	}
1130 
1131 	for (count = 0; count < nwqids; count++)
1132 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1133 			 count, wqids[count].type,
1134 			 wqids[count].path,
1135 			 wqids[count].version);
1136 
1137 	if (nwname)
1138 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1139 	else
1140 		memmove(&fid->qid, &oldfid->qid, sizeof(struct p9_qid));
1141 
1142 	kfree(wqids);
1143 	return fid;
1144 
1145 clunk_fid:
1146 	kfree(wqids);
1147 	p9_client_clunk(fid);
1148 	fid = NULL;
1149 
1150 error:
1151 	if (fid && fid != oldfid)
1152 		p9_fid_destroy(fid);
1153 
1154 	return ERR_PTR(err);
1155 }
1156 EXPORT_SYMBOL(p9_client_walk);
1157 
1158 int p9_client_open(struct p9_fid *fid, int mode)
1159 {
1160 	int err;
1161 	struct p9_client *clnt;
1162 	struct p9_req_t *req;
1163 	struct p9_qid qid;
1164 	int iounit;
1165 
1166 	clnt = fid->clnt;
1167 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1168 		 p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1169 	err = 0;
1170 
1171 	if (fid->mode != -1)
1172 		return -EINVAL;
1173 
1174 	if (p9_is_proto_dotl(clnt))
1175 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode);
1176 	else
1177 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
1178 	if (IS_ERR(req)) {
1179 		err = PTR_ERR(req);
1180 		goto error;
1181 	}
1182 
1183 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1184 	if (err) {
1185 		trace_9p_protocol_dump(clnt, &req->rc);
1186 		goto free_and_error;
1187 	}
1188 
1189 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1190 		 p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1191 		 qid.path, qid.version, iounit);
1192 
1193 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1194 	fid->mode = mode;
1195 	fid->iounit = iounit;
1196 
1197 free_and_error:
1198 	p9_tag_remove(clnt, req);
1199 error:
1200 	return err;
1201 }
1202 EXPORT_SYMBOL(p9_client_open);
1203 
1204 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags,
1205 			  u32 mode, kgid_t gid, struct p9_qid *qid)
1206 {
1207 	int err = 0;
1208 	struct p9_client *clnt;
1209 	struct p9_req_t *req;
1210 	int iounit;
1211 
1212 	p9_debug(P9_DEBUG_9P,
1213 		 ">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1214 		 ofid->fid, name, flags, mode,
1215 		 from_kgid(&init_user_ns, gid));
1216 	clnt = ofid->clnt;
1217 
1218 	if (ofid->mode != -1)
1219 		return -EINVAL;
1220 
1221 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1222 			    mode, gid);
1223 	if (IS_ERR(req)) {
1224 		err = PTR_ERR(req);
1225 		goto error;
1226 	}
1227 
1228 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", qid, &iounit);
1229 	if (err) {
1230 		trace_9p_protocol_dump(clnt, &req->rc);
1231 		goto free_and_error;
1232 	}
1233 
1234 	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1235 		 qid->type, qid->path, qid->version, iounit);
1236 
1237 	memmove(&ofid->qid, qid, sizeof(struct p9_qid));
1238 	ofid->mode = mode;
1239 	ofid->iounit = iounit;
1240 
1241 free_and_error:
1242 	p9_tag_remove(clnt, req);
1243 error:
1244 	return err;
1245 }
1246 EXPORT_SYMBOL(p9_client_create_dotl);
1247 
1248 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1249 		     char *extension)
1250 {
1251 	int err;
1252 	struct p9_client *clnt;
1253 	struct p9_req_t *req;
1254 	struct p9_qid qid;
1255 	int iounit;
1256 
1257 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1258 		 fid->fid, name, perm, mode);
1259 	err = 0;
1260 	clnt = fid->clnt;
1261 
1262 	if (fid->mode != -1)
1263 		return -EINVAL;
1264 
1265 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1266 			    mode, extension);
1267 	if (IS_ERR(req)) {
1268 		err = PTR_ERR(req);
1269 		goto error;
1270 	}
1271 
1272 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1273 	if (err) {
1274 		trace_9p_protocol_dump(clnt, &req->rc);
1275 		goto free_and_error;
1276 	}
1277 
1278 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1279 		 qid.type, qid.path, qid.version, iounit);
1280 
1281 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1282 	fid->mode = mode;
1283 	fid->iounit = iounit;
1284 
1285 free_and_error:
1286 	p9_tag_remove(clnt, req);
1287 error:
1288 	return err;
1289 }
1290 EXPORT_SYMBOL(p9_client_fcreate);
1291 
1292 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1293 		      const char *symtgt, kgid_t gid, struct p9_qid *qid)
1294 {
1295 	int err = 0;
1296 	struct p9_client *clnt;
1297 	struct p9_req_t *req;
1298 
1299 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1300 		 dfid->fid, name, symtgt);
1301 	clnt = dfid->clnt;
1302 
1303 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1304 			    gid);
1305 	if (IS_ERR(req)) {
1306 		err = PTR_ERR(req);
1307 		goto error;
1308 	}
1309 
1310 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
1311 	if (err) {
1312 		trace_9p_protocol_dump(clnt, &req->rc);
1313 		goto free_and_error;
1314 	}
1315 
1316 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1317 		 qid->type, qid->path, qid->version);
1318 
1319 free_and_error:
1320 	p9_tag_remove(clnt, req);
1321 error:
1322 	return err;
1323 }
1324 EXPORT_SYMBOL(p9_client_symlink);
1325 
1326 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1327 {
1328 	struct p9_client *clnt;
1329 	struct p9_req_t *req;
1330 
1331 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1332 		 dfid->fid, oldfid->fid, newname);
1333 	clnt = dfid->clnt;
1334 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1335 			    newname);
1336 	if (IS_ERR(req))
1337 		return PTR_ERR(req);
1338 
1339 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1340 	p9_tag_remove(clnt, req);
1341 	return 0;
1342 }
1343 EXPORT_SYMBOL(p9_client_link);
1344 
1345 int p9_client_fsync(struct p9_fid *fid, int datasync)
1346 {
1347 	int err;
1348 	struct p9_client *clnt;
1349 	struct p9_req_t *req;
1350 
1351 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1352 		 fid->fid, datasync);
1353 	err = 0;
1354 	clnt = fid->clnt;
1355 
1356 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1357 	if (IS_ERR(req)) {
1358 		err = PTR_ERR(req);
1359 		goto error;
1360 	}
1361 
1362 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1363 
1364 	p9_tag_remove(clnt, req);
1365 
1366 error:
1367 	return err;
1368 }
1369 EXPORT_SYMBOL(p9_client_fsync);
1370 
1371 int p9_client_clunk(struct p9_fid *fid)
1372 {
1373 	int err;
1374 	struct p9_client *clnt;
1375 	struct p9_req_t *req;
1376 	int retries = 0;
1377 
1378 	if (!fid || IS_ERR(fid)) {
1379 		pr_warn("%s (%d): Trying to clunk with invalid fid\n",
1380 			__func__, task_pid_nr(current));
1381 		dump_stack();
1382 		return 0;
1383 	}
1384 	if (!refcount_dec_and_test(&fid->count))
1385 		return 0;
1386 
1387 again:
1388 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n",
1389 		 fid->fid, retries);
1390 	err = 0;
1391 	clnt = fid->clnt;
1392 
1393 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1394 	if (IS_ERR(req)) {
1395 		err = PTR_ERR(req);
1396 		goto error;
1397 	}
1398 
1399 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1400 
1401 	p9_tag_remove(clnt, req);
1402 error:
1403 	/* Fid is not valid even after a failed clunk
1404 	 * If interrupted, retry once then give up and
1405 	 * leak fid until umount.
1406 	 */
1407 	if (err == -ERESTARTSYS) {
1408 		if (retries++ == 0)
1409 			goto again;
1410 	} else {
1411 		p9_fid_destroy(fid);
1412 	}
1413 	return err;
1414 }
1415 EXPORT_SYMBOL(p9_client_clunk);
1416 
1417 int p9_client_remove(struct p9_fid *fid)
1418 {
1419 	int err;
1420 	struct p9_client *clnt;
1421 	struct p9_req_t *req;
1422 
1423 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1424 	err = 0;
1425 	clnt = fid->clnt;
1426 
1427 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1428 	if (IS_ERR(req)) {
1429 		err = PTR_ERR(req);
1430 		goto error;
1431 	}
1432 
1433 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1434 
1435 	p9_tag_remove(clnt, req);
1436 error:
1437 	if (err == -ERESTARTSYS)
1438 		p9_client_clunk(fid);
1439 	else
1440 		p9_fid_destroy(fid);
1441 	return err;
1442 }
1443 EXPORT_SYMBOL(p9_client_remove);
1444 
1445 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1446 {
1447 	int err = 0;
1448 	struct p9_req_t *req;
1449 	struct p9_client *clnt;
1450 
1451 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1452 		 dfid->fid, name, flags);
1453 
1454 	clnt = dfid->clnt;
1455 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1456 	if (IS_ERR(req)) {
1457 		err = PTR_ERR(req);
1458 		goto error;
1459 	}
1460 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1461 
1462 	p9_tag_remove(clnt, req);
1463 error:
1464 	return err;
1465 }
1466 EXPORT_SYMBOL(p9_client_unlinkat);
1467 
1468 int
1469 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1470 {
1471 	int total = 0;
1472 	*err = 0;
1473 
1474 	while (iov_iter_count(to)) {
1475 		int count;
1476 
1477 		count = p9_client_read_once(fid, offset, to, err);
1478 		if (!count || *err)
1479 			break;
1480 		offset += count;
1481 		total += count;
1482 	}
1483 	return total;
1484 }
1485 EXPORT_SYMBOL(p9_client_read);
1486 
1487 int
1488 p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
1489 		    int *err)
1490 {
1491 	struct p9_client *clnt = fid->clnt;
1492 	struct p9_req_t *req;
1493 	int count = iov_iter_count(to);
1494 	int rsize, non_zc = 0;
1495 	char *dataptr;
1496 
1497 	*err = 0;
1498 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %zu\n",
1499 		 fid->fid, offset, iov_iter_count(to));
1500 
1501 	rsize = fid->iounit;
1502 	if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1503 		rsize = clnt->msize - P9_IOHDRSZ;
1504 
1505 	if (count < rsize)
1506 		rsize = count;
1507 
1508 	/* Don't bother zerocopy for small IO (< 1024) */
1509 	if (clnt->trans_mod->zc_request && rsize > 1024) {
1510 		/* response header len is 11
1511 		 * PDU Header(7) + IO Size (4)
1512 		 */
1513 		req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1514 				       0, 11, "dqd", fid->fid,
1515 				       offset, rsize);
1516 	} else {
1517 		non_zc = 1;
1518 		req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1519 				    rsize);
1520 	}
1521 	if (IS_ERR(req)) {
1522 		*err = PTR_ERR(req);
1523 		return 0;
1524 	}
1525 
1526 	*err = p9pdu_readf(&req->rc, clnt->proto_version,
1527 			   "D", &count, &dataptr);
1528 	if (*err) {
1529 		trace_9p_protocol_dump(clnt, &req->rc);
1530 		p9_tag_remove(clnt, req);
1531 		return 0;
1532 	}
1533 	if (rsize < count) {
1534 		pr_err("bogus RREAD count (%d > %d)\n", count, rsize);
1535 		count = rsize;
1536 	}
1537 
1538 	p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1539 
1540 	if (non_zc) {
1541 		int n = copy_to_iter(dataptr, count, to);
1542 
1543 		if (n != count) {
1544 			*err = -EFAULT;
1545 			p9_tag_remove(clnt, req);
1546 			return n;
1547 		}
1548 	} else {
1549 		iov_iter_advance(to, count);
1550 	}
1551 	p9_tag_remove(clnt, req);
1552 	return count;
1553 }
1554 EXPORT_SYMBOL(p9_client_read_once);
1555 
1556 int
1557 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1558 {
1559 	struct p9_client *clnt = fid->clnt;
1560 	struct p9_req_t *req;
1561 	int total = 0;
1562 	*err = 0;
1563 
1564 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n",
1565 		 fid->fid, offset, iov_iter_count(from));
1566 
1567 	while (iov_iter_count(from)) {
1568 		int count = iov_iter_count(from);
1569 		int rsize = fid->iounit;
1570 
1571 		if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1572 			rsize = clnt->msize - P9_IOHDRSZ;
1573 
1574 		if (count < rsize)
1575 			rsize = count;
1576 
1577 		/* Don't bother zerocopy for small IO (< 1024) */
1578 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1579 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1580 					       rsize, P9_ZC_HDR_SZ, "dqd",
1581 					       fid->fid, offset, rsize);
1582 		} else {
1583 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1584 					    offset, rsize, from);
1585 		}
1586 		if (IS_ERR(req)) {
1587 			*err = PTR_ERR(req);
1588 			break;
1589 		}
1590 
1591 		*err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &count);
1592 		if (*err) {
1593 			trace_9p_protocol_dump(clnt, &req->rc);
1594 			p9_tag_remove(clnt, req);
1595 			break;
1596 		}
1597 		if (rsize < count) {
1598 			pr_err("bogus RWRITE count (%d > %d)\n", count, rsize);
1599 			count = rsize;
1600 		}
1601 
1602 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1603 
1604 		p9_tag_remove(clnt, req);
1605 		iov_iter_advance(from, count);
1606 		total += count;
1607 		offset += count;
1608 	}
1609 	return total;
1610 }
1611 EXPORT_SYMBOL(p9_client_write);
1612 
1613 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1614 {
1615 	int err;
1616 	struct p9_client *clnt;
1617 	struct p9_wstat *ret;
1618 	struct p9_req_t *req;
1619 	u16 ignored;
1620 
1621 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1622 
1623 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1624 	if (!ret)
1625 		return ERR_PTR(-ENOMEM);
1626 
1627 	err = 0;
1628 	clnt = fid->clnt;
1629 
1630 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1631 	if (IS_ERR(req)) {
1632 		err = PTR_ERR(req);
1633 		goto error;
1634 	}
1635 
1636 	err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
1637 	if (err) {
1638 		trace_9p_protocol_dump(clnt, &req->rc);
1639 		p9_tag_remove(clnt, req);
1640 		goto error;
1641 	}
1642 
1643 	p9_debug(P9_DEBUG_9P,
1644 		 "<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1645 		 "<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1646 		 "<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1647 		 "<<<    uid=%d gid=%d n_muid=%d\n",
1648 		 ret->size, ret->type, ret->dev, ret->qid.type, ret->qid.path,
1649 		 ret->qid.version, ret->mode,
1650 		 ret->atime, ret->mtime, ret->length,
1651 		 ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1652 		 from_kuid(&init_user_ns, ret->n_uid),
1653 		 from_kgid(&init_user_ns, ret->n_gid),
1654 		 from_kuid(&init_user_ns, ret->n_muid));
1655 
1656 	p9_tag_remove(clnt, req);
1657 	return ret;
1658 
1659 error:
1660 	kfree(ret);
1661 	return ERR_PTR(err);
1662 }
1663 EXPORT_SYMBOL(p9_client_stat);
1664 
1665 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1666 					    u64 request_mask)
1667 {
1668 	int err;
1669 	struct p9_client *clnt;
1670 	struct p9_stat_dotl *ret;
1671 	struct p9_req_t *req;
1672 
1673 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1674 		 fid->fid, request_mask);
1675 
1676 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1677 	if (!ret)
1678 		return ERR_PTR(-ENOMEM);
1679 
1680 	err = 0;
1681 	clnt = fid->clnt;
1682 
1683 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1684 	if (IS_ERR(req)) {
1685 		err = PTR_ERR(req);
1686 		goto error;
1687 	}
1688 
1689 	err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
1690 	if (err) {
1691 		trace_9p_protocol_dump(clnt, &req->rc);
1692 		p9_tag_remove(clnt, req);
1693 		goto error;
1694 	}
1695 
1696 	p9_debug(P9_DEBUG_9P, "<<< RGETATTR st_result_mask=%lld\n"
1697 		 "<<< qid=%x.%llx.%x\n"
1698 		 "<<< st_mode=%8.8x st_nlink=%llu\n"
1699 		 "<<< st_uid=%d st_gid=%d\n"
1700 		 "<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1701 		 "<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1702 		 "<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1703 		 "<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1704 		 "<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1705 		 "<<< st_gen=%lld st_data_version=%lld\n",
1706 		 ret->st_result_mask,
1707 		 ret->qid.type, ret->qid.path, ret->qid.version,
1708 		 ret->st_mode, ret->st_nlink,
1709 		 from_kuid(&init_user_ns, ret->st_uid),
1710 		 from_kgid(&init_user_ns, ret->st_gid),
1711 		 ret->st_rdev, ret->st_size, ret->st_blksize, ret->st_blocks,
1712 		 ret->st_atime_sec, ret->st_atime_nsec,
1713 		 ret->st_mtime_sec, ret->st_mtime_nsec,
1714 		 ret->st_ctime_sec, ret->st_ctime_nsec,
1715 		 ret->st_btime_sec, ret->st_btime_nsec,
1716 		 ret->st_gen, ret->st_data_version);
1717 
1718 	p9_tag_remove(clnt, req);
1719 	return ret;
1720 
1721 error:
1722 	kfree(ret);
1723 	return ERR_PTR(err);
1724 }
1725 EXPORT_SYMBOL(p9_client_getattr_dotl);
1726 
1727 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1728 {
1729 	int ret;
1730 
1731 	/* NOTE: size shouldn't include its own length */
1732 	/* size[2] type[2] dev[4] qid[13] */
1733 	/* mode[4] atime[4] mtime[4] length[8]*/
1734 	/* name[s] uid[s] gid[s] muid[s] */
1735 	ret = 2 + 4 + 13 + 4 + 4 + 4 + 8 + 2 + 2 + 2 + 2;
1736 
1737 	if (wst->name)
1738 		ret += strlen(wst->name);
1739 	if (wst->uid)
1740 		ret += strlen(wst->uid);
1741 	if (wst->gid)
1742 		ret += strlen(wst->gid);
1743 	if (wst->muid)
1744 		ret += strlen(wst->muid);
1745 
1746 	if (proto_version == p9_proto_2000u ||
1747 	    proto_version == p9_proto_2000L) {
1748 		/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1749 		ret += 2 + 4 + 4 + 4;
1750 		if (wst->extension)
1751 			ret += strlen(wst->extension);
1752 	}
1753 
1754 	return ret;
1755 }
1756 
1757 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1758 {
1759 	int err;
1760 	struct p9_req_t *req;
1761 	struct p9_client *clnt;
1762 
1763 	err = 0;
1764 	clnt = fid->clnt;
1765 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1766 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n",
1767 		 fid->fid);
1768 	p9_debug(P9_DEBUG_9P,
1769 		 "     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1770 		 "     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1771 		 "     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1772 		 "     uid=%d gid=%d n_muid=%d\n",
1773 		 wst->size, wst->type, wst->dev, wst->qid.type,
1774 		 wst->qid.path, wst->qid.version,
1775 		 wst->mode, wst->atime, wst->mtime, wst->length,
1776 		 wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1777 		 from_kuid(&init_user_ns, wst->n_uid),
1778 		 from_kgid(&init_user_ns, wst->n_gid),
1779 		 from_kuid(&init_user_ns, wst->n_muid));
1780 
1781 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS",
1782 			    fid->fid, wst->size + 2, wst);
1783 	if (IS_ERR(req)) {
1784 		err = PTR_ERR(req);
1785 		goto error;
1786 	}
1787 
1788 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1789 
1790 	p9_tag_remove(clnt, req);
1791 error:
1792 	return err;
1793 }
1794 EXPORT_SYMBOL(p9_client_wstat);
1795 
1796 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1797 {
1798 	int err;
1799 	struct p9_req_t *req;
1800 	struct p9_client *clnt;
1801 
1802 	err = 0;
1803 	clnt = fid->clnt;
1804 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1805 	p9_debug(P9_DEBUG_9P, "    valid=%x mode=%x uid=%d gid=%d size=%lld\n",
1806 		 p9attr->valid, p9attr->mode,
1807 		 from_kuid(&init_user_ns, p9attr->uid),
1808 		 from_kgid(&init_user_ns, p9attr->gid),
1809 		 p9attr->size);
1810 	p9_debug(P9_DEBUG_9P, "    atime_sec=%lld atime_nsec=%lld\n",
1811 		 p9attr->atime_sec, p9attr->atime_nsec);
1812 	p9_debug(P9_DEBUG_9P, "    mtime_sec=%lld mtime_nsec=%lld\n",
1813 		 p9attr->mtime_sec, p9attr->mtime_nsec);
1814 
1815 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1816 
1817 	if (IS_ERR(req)) {
1818 		err = PTR_ERR(req);
1819 		goto error;
1820 	}
1821 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1822 	p9_tag_remove(clnt, req);
1823 error:
1824 	return err;
1825 }
1826 EXPORT_SYMBOL(p9_client_setattr);
1827 
1828 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1829 {
1830 	int err;
1831 	struct p9_req_t *req;
1832 	struct p9_client *clnt;
1833 
1834 	err = 0;
1835 	clnt = fid->clnt;
1836 
1837 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1838 
1839 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1840 	if (IS_ERR(req)) {
1841 		err = PTR_ERR(req);
1842 		goto error;
1843 	}
1844 
1845 	err = p9pdu_readf(&req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1846 			  &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1847 			  &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1848 	if (err) {
1849 		trace_9p_protocol_dump(clnt, &req->rc);
1850 		p9_tag_remove(clnt, req);
1851 		goto error;
1852 	}
1853 
1854 	p9_debug(P9_DEBUG_9P,
1855 		 "<<< RSTATFS fid %d type 0x%x bsize %u blocks %llu bfree %llu bavail %llu files %llu ffree %llu fsid %llu namelen %u\n",
1856 		 fid->fid, sb->type, sb->bsize, sb->blocks, sb->bfree,
1857 		 sb->bavail, sb->files, sb->ffree, sb->fsid, sb->namelen);
1858 
1859 	p9_tag_remove(clnt, req);
1860 error:
1861 	return err;
1862 }
1863 EXPORT_SYMBOL(p9_client_statfs);
1864 
1865 int p9_client_rename(struct p9_fid *fid,
1866 		     struct p9_fid *newdirfid, const char *name)
1867 {
1868 	int err;
1869 	struct p9_req_t *req;
1870 	struct p9_client *clnt;
1871 
1872 	err = 0;
1873 	clnt = fid->clnt;
1874 
1875 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1876 		 fid->fid, newdirfid->fid, name);
1877 
1878 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1879 			    newdirfid->fid, name);
1880 	if (IS_ERR(req)) {
1881 		err = PTR_ERR(req);
1882 		goto error;
1883 	}
1884 
1885 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1886 
1887 	p9_tag_remove(clnt, req);
1888 error:
1889 	return err;
1890 }
1891 EXPORT_SYMBOL(p9_client_rename);
1892 
1893 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
1894 		       struct p9_fid *newdirfid, const char *new_name)
1895 {
1896 	int err;
1897 	struct p9_req_t *req;
1898 	struct p9_client *clnt;
1899 
1900 	err = 0;
1901 	clnt = olddirfid->clnt;
1902 
1903 	p9_debug(P9_DEBUG_9P,
1904 		 ">>> TRENAMEAT olddirfid %d old name %s newdirfid %d new name %s\n",
1905 		 olddirfid->fid, old_name, newdirfid->fid, new_name);
1906 
1907 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
1908 			    old_name, newdirfid->fid, new_name);
1909 	if (IS_ERR(req)) {
1910 		err = PTR_ERR(req);
1911 		goto error;
1912 	}
1913 
1914 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
1915 		 newdirfid->fid, new_name);
1916 
1917 	p9_tag_remove(clnt, req);
1918 error:
1919 	return err;
1920 }
1921 EXPORT_SYMBOL(p9_client_renameat);
1922 
1923 /* An xattrwalk without @attr_name gives the fid for the lisxattr namespace
1924  */
1925 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
1926 				   const char *attr_name, u64 *attr_size)
1927 {
1928 	int err;
1929 	struct p9_req_t *req;
1930 	struct p9_client *clnt;
1931 	struct p9_fid *attr_fid;
1932 
1933 	err = 0;
1934 	clnt = file_fid->clnt;
1935 	attr_fid = p9_fid_create(clnt);
1936 	if (!attr_fid) {
1937 		err = -ENOMEM;
1938 		goto error;
1939 	}
1940 	p9_debug(P9_DEBUG_9P,
1941 		 ">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
1942 		 file_fid->fid, attr_fid->fid, attr_name);
1943 
1944 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
1945 			    file_fid->fid, attr_fid->fid, attr_name);
1946 	if (IS_ERR(req)) {
1947 		err = PTR_ERR(req);
1948 		goto error;
1949 	}
1950 	err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
1951 	if (err) {
1952 		trace_9p_protocol_dump(clnt, &req->rc);
1953 		p9_tag_remove(clnt, req);
1954 		goto clunk_fid;
1955 	}
1956 	p9_tag_remove(clnt, req);
1957 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
1958 		 attr_fid->fid, *attr_size);
1959 	return attr_fid;
1960 clunk_fid:
1961 	p9_client_clunk(attr_fid);
1962 	attr_fid = NULL;
1963 error:
1964 	if (attr_fid && attr_fid != file_fid)
1965 		p9_fid_destroy(attr_fid);
1966 
1967 	return ERR_PTR(err);
1968 }
1969 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
1970 
1971 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
1972 			  u64 attr_size, int flags)
1973 {
1974 	int err;
1975 	struct p9_req_t *req;
1976 	struct p9_client *clnt;
1977 
1978 	p9_debug(P9_DEBUG_9P,
1979 		 ">>> TXATTRCREATE fid %d name  %s size %llu flag %d\n",
1980 		 fid->fid, name, attr_size, flags);
1981 	err = 0;
1982 	clnt = fid->clnt;
1983 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
1984 			    fid->fid, name, attr_size, flags);
1985 	if (IS_ERR(req)) {
1986 		err = PTR_ERR(req);
1987 		goto error;
1988 	}
1989 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
1990 	p9_tag_remove(clnt, req);
1991 error:
1992 	return err;
1993 }
1994 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
1995 
1996 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
1997 {
1998 	int err, rsize, non_zc = 0;
1999 	struct p9_client *clnt;
2000 	struct p9_req_t *req;
2001 	char *dataptr;
2002 	struct kvec kv = {.iov_base = data, .iov_len = count};
2003 	struct iov_iter to;
2004 
2005 	iov_iter_kvec(&to, READ, &kv, 1, count);
2006 
2007 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
2008 		 fid->fid, offset, count);
2009 
2010 	err = 0;
2011 	clnt = fid->clnt;
2012 
2013 	rsize = fid->iounit;
2014 	if (!rsize || rsize > clnt->msize - P9_READDIRHDRSZ)
2015 		rsize = clnt->msize - P9_READDIRHDRSZ;
2016 
2017 	if (count < rsize)
2018 		rsize = count;
2019 
2020 	/* Don't bother zerocopy for small IO (< 1024) */
2021 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2022 		/* response header len is 11
2023 		 * PDU Header(7) + IO Size (4)
2024 		 */
2025 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2026 				       11, "dqd", fid->fid, offset, rsize);
2027 	} else {
2028 		non_zc = 1;
2029 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2030 				    offset, rsize);
2031 	}
2032 	if (IS_ERR(req)) {
2033 		err = PTR_ERR(req);
2034 		goto error;
2035 	}
2036 
2037 	err = p9pdu_readf(&req->rc, clnt->proto_version, "D", &count, &dataptr);
2038 	if (err) {
2039 		trace_9p_protocol_dump(clnt, &req->rc);
2040 		goto free_and_error;
2041 	}
2042 	if (rsize < count) {
2043 		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
2044 		count = rsize;
2045 	}
2046 
2047 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
2048 
2049 	if (non_zc)
2050 		memmove(data, dataptr, count);
2051 
2052 	p9_tag_remove(clnt, req);
2053 	return count;
2054 
2055 free_and_error:
2056 	p9_tag_remove(clnt, req);
2057 error:
2058 	return err;
2059 }
2060 EXPORT_SYMBOL(p9_client_readdir);
2061 
2062 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2063 			 dev_t rdev, kgid_t gid, struct p9_qid *qid)
2064 {
2065 	int err;
2066 	struct p9_client *clnt;
2067 	struct p9_req_t *req;
2068 
2069 	err = 0;
2070 	clnt = fid->clnt;
2071 	p9_debug(P9_DEBUG_9P,
2072 		 ">>> TMKNOD fid %d name %s mode %d major %d minor %d\n",
2073 		 fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2074 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2075 			    MAJOR(rdev), MINOR(rdev), gid);
2076 	if (IS_ERR(req))
2077 		return PTR_ERR(req);
2078 
2079 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2080 	if (err) {
2081 		trace_9p_protocol_dump(clnt, &req->rc);
2082 		goto error;
2083 	}
2084 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n",
2085 		 qid->type, qid->path, qid->version);
2086 
2087 error:
2088 	p9_tag_remove(clnt, req);
2089 	return err;
2090 }
2091 EXPORT_SYMBOL(p9_client_mknod_dotl);
2092 
2093 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2094 			 kgid_t gid, struct p9_qid *qid)
2095 {
2096 	int err;
2097 	struct p9_client *clnt;
2098 	struct p9_req_t *req;
2099 
2100 	err = 0;
2101 	clnt = fid->clnt;
2102 	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
2103 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
2104 	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg",
2105 			    fid->fid, name, mode, gid);
2106 	if (IS_ERR(req))
2107 		return PTR_ERR(req);
2108 
2109 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2110 	if (err) {
2111 		trace_9p_protocol_dump(clnt, &req->rc);
2112 		goto error;
2113 	}
2114 	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
2115 		 qid->path, qid->version);
2116 
2117 error:
2118 	p9_tag_remove(clnt, req);
2119 	return err;
2120 }
2121 EXPORT_SYMBOL(p9_client_mkdir_dotl);
2122 
2123 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
2124 {
2125 	int err;
2126 	struct p9_client *clnt;
2127 	struct p9_req_t *req;
2128 
2129 	err = 0;
2130 	clnt = fid->clnt;
2131 	p9_debug(P9_DEBUG_9P,
2132 		 ">>> TLOCK fid %d type %i flags %d start %lld length %lld proc_id %d client_id %s\n",
2133 		 fid->fid, flock->type, flock->flags, flock->start,
2134 		 flock->length, flock->proc_id, flock->client_id);
2135 
2136 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2137 			    flock->flags, flock->start, flock->length,
2138 			    flock->proc_id, flock->client_id);
2139 
2140 	if (IS_ERR(req))
2141 		return PTR_ERR(req);
2142 
2143 	err = p9pdu_readf(&req->rc, clnt->proto_version, "b", status);
2144 	if (err) {
2145 		trace_9p_protocol_dump(clnt, &req->rc);
2146 		goto error;
2147 	}
2148 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2149 error:
2150 	p9_tag_remove(clnt, req);
2151 	return err;
2152 }
2153 EXPORT_SYMBOL(p9_client_lock_dotl);
2154 
2155 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2156 {
2157 	int err;
2158 	struct p9_client *clnt;
2159 	struct p9_req_t *req;
2160 
2161 	err = 0;
2162 	clnt = fid->clnt;
2163 	p9_debug(P9_DEBUG_9P,
2164 		 ">>> TGETLOCK fid %d, type %i start %lld length %lld proc_id %d client_id %s\n",
2165 		 fid->fid, glock->type, glock->start, glock->length,
2166 		 glock->proc_id, glock->client_id);
2167 
2168 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,
2169 			    glock->type, glock->start, glock->length,
2170 			    glock->proc_id, glock->client_id);
2171 
2172 	if (IS_ERR(req))
2173 		return PTR_ERR(req);
2174 
2175 	err = p9pdu_readf(&req->rc, clnt->proto_version, "bqqds", &glock->type,
2176 			  &glock->start, &glock->length, &glock->proc_id,
2177 			  &glock->client_id);
2178 	if (err) {
2179 		trace_9p_protocol_dump(clnt, &req->rc);
2180 		goto error;
2181 	}
2182 	p9_debug(P9_DEBUG_9P,
2183 		 "<<< RGETLOCK type %i start %lld length %lld proc_id %d client_id %s\n",
2184 		 glock->type, glock->start, glock->length,
2185 		 glock->proc_id, glock->client_id);
2186 error:
2187 	p9_tag_remove(clnt, req);
2188 	return err;
2189 }
2190 EXPORT_SYMBOL(p9_client_getlock_dotl);
2191 
2192 int p9_client_readlink(struct p9_fid *fid, char **target)
2193 {
2194 	int err;
2195 	struct p9_client *clnt;
2196 	struct p9_req_t *req;
2197 
2198 	err = 0;
2199 	clnt = fid->clnt;
2200 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2201 
2202 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2203 	if (IS_ERR(req))
2204 		return PTR_ERR(req);
2205 
2206 	err = p9pdu_readf(&req->rc, clnt->proto_version, "s", target);
2207 	if (err) {
2208 		trace_9p_protocol_dump(clnt, &req->rc);
2209 		goto error;
2210 	}
2211 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2212 error:
2213 	p9_tag_remove(clnt, req);
2214 	return err;
2215 }
2216 EXPORT_SYMBOL(p9_client_readlink);
2217 
2218 int __init p9_client_init(void)
2219 {
2220 	p9_req_cache = KMEM_CACHE(p9_req_t, SLAB_TYPESAFE_BY_RCU);
2221 	return p9_req_cache ? 0 : -ENOMEM;
2222 }
2223 
2224 void __exit p9_client_exit(void)
2225 {
2226 	kmem_cache_destroy(p9_req_cache);
2227 }
2228