xref: /linux/net/9p/client.c (revision f949cb759051b24aa6cacda73964327608c08a89)
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 /* DEFAULT MSIZE = 32 pages worth of payload + P9_HDRSZ +
32  * room for write (16 extra) or read (11 extra) operands.
33  */
34 
35 #define DEFAULT_MSIZE ((128 * 1024) + P9_IOHDRSZ)
36 
37 /* Client Option Parsing (code inspired by NFS code)
38  *  - a little lazy - parse all client options
39  */
40 
41 enum {
42 	Opt_msize,
43 	Opt_trans,
44 	Opt_legacy,
45 	Opt_version,
46 	Opt_err,
47 };
48 
49 static const match_table_t tokens = {
50 	{Opt_msize, "msize=%u"},
51 	{Opt_legacy, "noextend"},
52 	{Opt_trans, "trans=%s"},
53 	{Opt_version, "version=%s"},
54 	{Opt_err, NULL},
55 };
56 
57 inline int p9_is_proto_dotl(struct p9_client *clnt)
58 {
59 	return clnt->proto_version == p9_proto_2000L;
60 }
61 EXPORT_SYMBOL(p9_is_proto_dotl);
62 
63 inline int p9_is_proto_dotu(struct p9_client *clnt)
64 {
65 	return clnt->proto_version == p9_proto_2000u;
66 }
67 EXPORT_SYMBOL(p9_is_proto_dotu);
68 
69 int p9_show_client_options(struct seq_file *m, struct p9_client *clnt)
70 {
71 	if (clnt->msize != DEFAULT_MSIZE)
72 		seq_printf(m, ",msize=%u", clnt->msize);
73 	seq_printf(m, ",trans=%s", clnt->trans_mod->name);
74 
75 	switch (clnt->proto_version) {
76 	case p9_proto_legacy:
77 		seq_puts(m, ",noextend");
78 		break;
79 	case p9_proto_2000u:
80 		seq_puts(m, ",version=9p2000.u");
81 		break;
82 	case p9_proto_2000L:
83 		/* Default */
84 		break;
85 	}
86 
87 	if (clnt->trans_mod->show_options)
88 		return clnt->trans_mod->show_options(m, clnt);
89 	return 0;
90 }
91 EXPORT_SYMBOL(p9_show_client_options);
92 
93 /* Some error codes are taken directly from the server replies,
94  * make sure they are valid.
95  */
96 static int safe_errno(int err)
97 {
98 	if (err > 0 || err < -MAX_ERRNO) {
99 		p9_debug(P9_DEBUG_ERROR, "Invalid error code %d\n", err);
100 		return -EPROTO;
101 	}
102 	return err;
103 }
104 
105 /* Interpret mount option for protocol version */
106 static int get_protocol_version(char *s)
107 {
108 	int version = -EINVAL;
109 
110 	if (!strcmp(s, "9p2000")) {
111 		version = p9_proto_legacy;
112 		p9_debug(P9_DEBUG_9P, "Protocol version: Legacy\n");
113 	} else if (!strcmp(s, "9p2000.u")) {
114 		version = p9_proto_2000u;
115 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.u\n");
116 	} else if (!strcmp(s, "9p2000.L")) {
117 		version = p9_proto_2000L;
118 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.L\n");
119 	} else {
120 		pr_info("Unknown protocol version %s\n", s);
121 	}
122 
123 	return version;
124 }
125 
126 /**
127  * parse_opts - parse mount options into client structure
128  * @opts: options string passed from mount
129  * @clnt: existing v9fs client information
130  *
131  * Return 0 upon success, -ERRNO upon failure
132  */
133 
134 static int parse_opts(char *opts, struct p9_client *clnt)
135 {
136 	char *options, *tmp_options;
137 	char *p;
138 	substring_t args[MAX_OPT_ARGS];
139 	int option;
140 	char *s;
141 	int ret = 0;
142 
143 	clnt->proto_version = p9_proto_2000L;
144 	clnt->msize = DEFAULT_MSIZE;
145 
146 	if (!opts)
147 		return 0;
148 
149 	tmp_options = kstrdup(opts, GFP_KERNEL);
150 	if (!tmp_options)
151 		return -ENOMEM;
152 	options = tmp_options;
153 
154 	while ((p = strsep(&options, ",")) != NULL) {
155 		int token, r;
156 
157 		if (!*p)
158 			continue;
159 		token = match_token(p, tokens, args);
160 		switch (token) {
161 		case Opt_msize:
162 			r = match_int(&args[0], &option);
163 			if (r < 0) {
164 				p9_debug(P9_DEBUG_ERROR,
165 					 "integer field, but no integer?\n");
166 				ret = r;
167 				continue;
168 			}
169 			if (option < 4096) {
170 				p9_debug(P9_DEBUG_ERROR,
171 					 "msize should be at least 4k\n");
172 				ret = -EINVAL;
173 				continue;
174 			}
175 			clnt->msize = option;
176 			break;
177 		case Opt_trans:
178 			s = match_strdup(&args[0]);
179 			if (!s) {
180 				ret = -ENOMEM;
181 				p9_debug(P9_DEBUG_ERROR,
182 					 "problem allocating copy of trans arg\n");
183 				goto free_and_return;
184 			}
185 
186 			v9fs_put_trans(clnt->trans_mod);
187 			clnt->trans_mod = v9fs_get_trans_by_name(s);
188 			if (!clnt->trans_mod) {
189 				pr_info("Could not find request transport: %s\n",
190 					s);
191 				ret = -EINVAL;
192 			}
193 			kfree(s);
194 			break;
195 		case Opt_legacy:
196 			clnt->proto_version = p9_proto_legacy;
197 			break;
198 		case Opt_version:
199 			s = match_strdup(&args[0]);
200 			if (!s) {
201 				ret = -ENOMEM;
202 				p9_debug(P9_DEBUG_ERROR,
203 					 "problem allocating copy of version arg\n");
204 				goto free_and_return;
205 			}
206 			r = get_protocol_version(s);
207 			if (r < 0)
208 				ret = r;
209 			else
210 				clnt->proto_version = r;
211 			kfree(s);
212 			break;
213 		default:
214 			continue;
215 		}
216 	}
217 
218 free_and_return:
219 	if (ret)
220 		v9fs_put_trans(clnt->trans_mod);
221 	kfree(tmp_options);
222 	return ret;
223 }
224 
225 static int p9_fcall_init(struct p9_client *c, struct p9_fcall *fc,
226 			 int alloc_msize)
227 {
228 	if (likely(c->fcall_cache) && alloc_msize == c->msize) {
229 		fc->sdata = kmem_cache_alloc(c->fcall_cache, GFP_NOFS);
230 		fc->cache = c->fcall_cache;
231 	} else {
232 		fc->sdata = kmalloc(alloc_msize, GFP_NOFS);
233 		fc->cache = NULL;
234 	}
235 	if (!fc->sdata)
236 		return -ENOMEM;
237 	fc->capacity = alloc_msize;
238 	return 0;
239 }
240 
241 void p9_fcall_fini(struct p9_fcall *fc)
242 {
243 	/* sdata can be NULL for interrupted requests in trans_rdma,
244 	 * and kmem_cache_free does not do NULL-check for us
245 	 */
246 	if (unlikely(!fc->sdata))
247 		return;
248 
249 	if (fc->cache)
250 		kmem_cache_free(fc->cache, fc->sdata);
251 	else
252 		kfree(fc->sdata);
253 }
254 EXPORT_SYMBOL(p9_fcall_fini);
255 
256 static struct kmem_cache *p9_req_cache;
257 
258 /**
259  * p9_tag_alloc - Allocate a new request.
260  * @c: Client session.
261  * @type: Transaction type.
262  * @t_size: Buffer size for holding this request
263  * (automatic calculation by format template if 0).
264  * @r_size: Buffer size for holding server's reply on this request
265  * (automatic calculation by format template if 0).
266  * @fmt: Format template for assembling 9p request message
267  * (see p9pdu_vwritef).
268  * @ap: Variable arguments to be fed to passed format template
269  * (see p9pdu_vwritef).
270  *
271  * Context: Process context.
272  * Return: Pointer to new request.
273  */
274 static struct p9_req_t *
275 p9_tag_alloc(struct p9_client *c, int8_t type, uint t_size, uint r_size,
276 	      const char *fmt, va_list ap)
277 {
278 	struct p9_req_t *req = kmem_cache_alloc(p9_req_cache, GFP_NOFS);
279 	int alloc_tsize;
280 	int alloc_rsize;
281 	int tag;
282 	va_list apc;
283 
284 	va_copy(apc, ap);
285 	alloc_tsize = min_t(size_t, c->msize,
286 			    t_size ?: p9_msg_buf_size(c, type, fmt, apc));
287 	va_end(apc);
288 
289 	alloc_rsize = min_t(size_t, c->msize,
290 			    r_size ?: p9_msg_buf_size(c, type + 1, fmt, ap));
291 
292 	if (!req)
293 		return ERR_PTR(-ENOMEM);
294 
295 	if (p9_fcall_init(c, &req->tc, alloc_tsize))
296 		goto free_req;
297 	if (p9_fcall_init(c, &req->rc, alloc_rsize))
298 		goto free;
299 
300 	p9pdu_reset(&req->tc);
301 	p9pdu_reset(&req->rc);
302 	req->t_err = 0;
303 	req->status = REQ_STATUS_ALLOC;
304 	/* refcount needs to be set to 0 before inserting into the idr
305 	 * so p9_tag_lookup does not accept a request that is not fully
306 	 * initialized. refcount_set to 2 below will mark request ready.
307 	 */
308 	refcount_set(&req->refcount, 0);
309 	init_waitqueue_head(&req->wq);
310 	INIT_LIST_HEAD(&req->req_list);
311 
312 	idr_preload(GFP_NOFS);
313 	spin_lock_irq(&c->lock);
314 	if (type == P9_TVERSION)
315 		tag = idr_alloc(&c->reqs, req, P9_NOTAG, P9_NOTAG + 1,
316 				GFP_NOWAIT);
317 	else
318 		tag = idr_alloc(&c->reqs, req, 0, P9_NOTAG, GFP_NOWAIT);
319 	req->tc.tag = tag;
320 	spin_unlock_irq(&c->lock);
321 	idr_preload_end();
322 	if (tag < 0)
323 		goto free;
324 
325 	/* Init ref to two because in the general case there is one ref
326 	 * that is put asynchronously by a writer thread, one ref
327 	 * temporarily given by p9_tag_lookup and put by p9_client_cb
328 	 * in the recv thread, and one ref put by p9_req_put in the
329 	 * main thread. The only exception is virtio that does not use
330 	 * p9_tag_lookup but does not have a writer thread either
331 	 * (the write happens synchronously in the request/zc_request
332 	 * callback), so p9_client_cb eats the second ref there
333 	 * as the pointer is duplicated directly by virtqueue_add_sgs()
334 	 */
335 	refcount_set(&req->refcount, 2);
336 
337 	return req;
338 
339 free:
340 	p9_fcall_fini(&req->tc);
341 	p9_fcall_fini(&req->rc);
342 free_req:
343 	kmem_cache_free(p9_req_cache, req);
344 	return ERR_PTR(-ENOMEM);
345 }
346 
347 /**
348  * p9_tag_lookup - Look up a request by tag.
349  * @c: Client session.
350  * @tag: Transaction ID.
351  *
352  * Context: Any context.
353  * Return: A request, or %NULL if there is no request with that tag.
354  */
355 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
356 {
357 	struct p9_req_t *req;
358 
359 	rcu_read_lock();
360 again:
361 	req = idr_find(&c->reqs, tag);
362 	if (req) {
363 		/* We have to be careful with the req found under rcu_read_lock
364 		 * Thanks to SLAB_TYPESAFE_BY_RCU we can safely try to get the
365 		 * ref again without corrupting other data, then check again
366 		 * that the tag matches once we have the ref
367 		 */
368 		if (!p9_req_try_get(req))
369 			goto again;
370 		if (req->tc.tag != tag) {
371 			p9_req_put(c, req);
372 			goto again;
373 		}
374 	}
375 	rcu_read_unlock();
376 
377 	return req;
378 }
379 EXPORT_SYMBOL(p9_tag_lookup);
380 
381 /**
382  * p9_tag_remove - Remove a tag.
383  * @c: Client session.
384  * @r: Request of reference.
385  *
386  * Context: Any context.
387  */
388 static void p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
389 {
390 	unsigned long flags;
391 	u16 tag = r->tc.tag;
392 
393 	p9_debug(P9_DEBUG_MUX, "freeing clnt %p req %p tag: %d\n", c, r, tag);
394 	spin_lock_irqsave(&c->lock, flags);
395 	idr_remove(&c->reqs, tag);
396 	spin_unlock_irqrestore(&c->lock, flags);
397 }
398 
399 int p9_req_put(struct p9_client *c, struct p9_req_t *r)
400 {
401 	if (refcount_dec_and_test(&r->refcount)) {
402 		p9_tag_remove(c, r);
403 
404 		p9_fcall_fini(&r->tc);
405 		p9_fcall_fini(&r->rc);
406 		kmem_cache_free(p9_req_cache, r);
407 		return 1;
408 	}
409 	return 0;
410 }
411 EXPORT_SYMBOL(p9_req_put);
412 
413 /**
414  * p9_tag_cleanup - cleans up tags structure and reclaims resources
415  * @c:  v9fs client struct
416  *
417  * This frees resources associated with the tags structure
418  *
419  */
420 static void p9_tag_cleanup(struct p9_client *c)
421 {
422 	struct p9_req_t *req;
423 	int id;
424 
425 	rcu_read_lock();
426 	idr_for_each_entry(&c->reqs, req, id) {
427 		pr_info("Tag %d still in use\n", id);
428 		if (p9_req_put(c, req) == 0)
429 			pr_warn("Packet with tag %d has still references",
430 				req->tc.tag);
431 	}
432 	rcu_read_unlock();
433 }
434 
435 /**
436  * p9_client_cb - call back from transport to client
437  * @c: client state
438  * @req: request received
439  * @status: request status, one of REQ_STATUS_*
440  *
441  */
442 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
443 {
444 	p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc.tag);
445 
446 	/* This barrier is needed to make sure any change made to req before
447 	 * the status change is visible to another thread
448 	 */
449 	smp_wmb();
450 	WRITE_ONCE(req->status, status);
451 
452 	wake_up(&req->wq);
453 	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
454 	p9_req_put(c, req);
455 }
456 EXPORT_SYMBOL(p9_client_cb);
457 
458 /**
459  * p9_parse_header - parse header arguments out of a packet
460  * @pdu: packet to parse
461  * @size: size of packet
462  * @type: type of request
463  * @tag: tag of packet
464  * @rewind: set if we need to rewind offset afterwards
465  */
466 
467 int
468 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type,
469 		int16_t *tag, int rewind)
470 {
471 	s8 r_type;
472 	s16 r_tag;
473 	s32 r_size;
474 	int offset = pdu->offset;
475 	int err;
476 
477 	pdu->offset = 0;
478 
479 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
480 	if (err)
481 		goto rewind_and_exit;
482 
483 	if (type)
484 		*type = r_type;
485 	if (tag)
486 		*tag = r_tag;
487 	if (size)
488 		*size = r_size;
489 
490 	if (pdu->size != r_size || r_size < 7) {
491 		err = -EINVAL;
492 		goto rewind_and_exit;
493 	}
494 
495 	pdu->id = r_type;
496 	pdu->tag = r_tag;
497 
498 	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
499 		 pdu->size, pdu->id, pdu->tag);
500 
501 rewind_and_exit:
502 	if (rewind)
503 		pdu->offset = offset;
504 	return err;
505 }
506 EXPORT_SYMBOL(p9_parse_header);
507 
508 /**
509  * p9_check_errors - check 9p packet for error return and process it
510  * @c: current client instance
511  * @req: request to parse and check for error conditions
512  *
513  * returns error code if one is discovered, otherwise returns 0
514  *
515  * this will have to be more complicated if we have multiple
516  * error packet types
517  */
518 
519 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
520 {
521 	s8 type;
522 	int err;
523 	int ecode;
524 
525 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
526 	if (req->rc.size > req->rc.capacity && !req->rc.zc) {
527 		pr_err("requested packet size too big: %d does not fit %zu (type=%d)\n",
528 		       req->rc.size, req->rc.capacity, req->rc.id);
529 		return -EIO;
530 	}
531 	/* dump the response from server
532 	 * This should be after check errors which poplulate pdu_fcall.
533 	 */
534 	trace_9p_protocol_dump(c, &req->rc);
535 	if (err) {
536 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
537 		return err;
538 	}
539 	if (type != P9_RERROR && type != P9_RLERROR)
540 		return 0;
541 
542 	if (!p9_is_proto_dotl(c)) {
543 		char *ename;
544 
545 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
546 				  &ename, &ecode);
547 		if (err)
548 			goto out_err;
549 
550 		if (p9_is_proto_dotu(c) && ecode < 512)
551 			err = -ecode;
552 
553 		if (!err) {
554 			err = p9_errstr2errno(ename, strlen(ename));
555 
556 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
557 				 -ecode, ename);
558 		}
559 		kfree(ename);
560 	} else {
561 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
562 		if (err)
563 			goto out_err;
564 		err = -ecode;
565 
566 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
567 	}
568 
569 	return err;
570 
571 out_err:
572 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
573 
574 	return err;
575 }
576 
577 static struct p9_req_t *
578 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
579 
580 /**
581  * p9_client_flush - flush (cancel) a request
582  * @c: client state
583  * @oldreq: request to cancel
584  *
585  * This sents a flush for a particular request and links
586  * the flush request to the original request.  The current
587  * code only supports a single flush request although the protocol
588  * allows for multiple flush requests to be sent for a single request.
589  *
590  */
591 
592 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
593 {
594 	struct p9_req_t *req;
595 	s16 oldtag;
596 	int err;
597 
598 	err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
599 	if (err)
600 		return err;
601 
602 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
603 
604 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
605 	if (IS_ERR(req))
606 		return PTR_ERR(req);
607 
608 	/* if we haven't received a response for oldreq,
609 	 * remove it from the list
610 	 */
611 	if (READ_ONCE(oldreq->status) == REQ_STATUS_SENT) {
612 		if (c->trans_mod->cancelled)
613 			c->trans_mod->cancelled(c, oldreq);
614 	}
615 
616 	p9_req_put(c, req);
617 	return 0;
618 }
619 
620 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
621 					      int8_t type, uint t_size, uint r_size,
622 					      const char *fmt, va_list ap)
623 {
624 	int err;
625 	struct p9_req_t *req;
626 	va_list apc;
627 
628 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
629 
630 	/* we allow for any status other than disconnected */
631 	if (c->status == Disconnected)
632 		return ERR_PTR(-EIO);
633 
634 	/* if status is begin_disconnected we allow only clunk request */
635 	if (c->status == BeginDisconnect && type != P9_TCLUNK)
636 		return ERR_PTR(-EIO);
637 
638 	va_copy(apc, ap);
639 	req = p9_tag_alloc(c, type, t_size, r_size, fmt, apc);
640 	va_end(apc);
641 	if (IS_ERR(req))
642 		return req;
643 
644 	/* marshall the data */
645 	p9pdu_prepare(&req->tc, req->tc.tag, type);
646 	err = p9pdu_vwritef(&req->tc, c->proto_version, fmt, ap);
647 	if (err)
648 		goto reterr;
649 	p9pdu_finalize(c, &req->tc);
650 	trace_9p_client_req(c, type, req->tc.tag);
651 	return req;
652 reterr:
653 	p9_req_put(c, req);
654 	/* We have to put also the 2nd reference as it won't be used */
655 	p9_req_put(c, req);
656 	return ERR_PTR(err);
657 }
658 
659 /**
660  * p9_client_rpc - issue a request and wait for a response
661  * @c: client session
662  * @type: type of request
663  * @fmt: protocol format string (see protocol.c)
664  *
665  * Returns request structure (which client must free using p9_req_put)
666  */
667 
668 static struct p9_req_t *
669 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
670 {
671 	va_list ap;
672 	int sigpending, err;
673 	unsigned long flags;
674 	struct p9_req_t *req;
675 	/* Passing zero for tsize/rsize to p9_client_prepare_req() tells it to
676 	 * auto determine an appropriate (small) request/response size
677 	 * according to actual message data being sent. Currently RDMA
678 	 * transport is excluded from this response message size optimization,
679 	 * as it would not cope with it, due to its pooled response buffers
680 	 * (using an optimized request size for RDMA as well though).
681 	 */
682 	const uint tsize = 0;
683 	const uint rsize = c->trans_mod->pooled_rbuffers ? c->msize : 0;
684 
685 	va_start(ap, fmt);
686 	req = p9_client_prepare_req(c, type, tsize, rsize, fmt, ap);
687 	va_end(ap);
688 	if (IS_ERR(req))
689 		return req;
690 
691 	req->tc.zc = false;
692 	req->rc.zc = false;
693 
694 	if (signal_pending(current)) {
695 		sigpending = 1;
696 		clear_thread_flag(TIF_SIGPENDING);
697 	} else {
698 		sigpending = 0;
699 	}
700 
701 	err = c->trans_mod->request(c, req);
702 	if (err < 0) {
703 		/* write won't happen */
704 		p9_req_put(c, req);
705 		if (err != -ERESTARTSYS && err != -EFAULT)
706 			c->status = Disconnected;
707 		goto recalc_sigpending;
708 	}
709 again:
710 	/* Wait for the response */
711 	err = wait_event_killable(req->wq,
712 				  READ_ONCE(req->status) >= REQ_STATUS_RCVD);
713 
714 	/* Make sure our req is coherent with regard to updates in other
715 	 * threads - echoes to wmb() in the callback
716 	 */
717 	smp_rmb();
718 
719 	if (err == -ERESTARTSYS && c->status == Connected &&
720 	    type == P9_TFLUSH) {
721 		sigpending = 1;
722 		clear_thread_flag(TIF_SIGPENDING);
723 		goto again;
724 	}
725 
726 	if (READ_ONCE(req->status) == REQ_STATUS_ERROR) {
727 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
728 		err = req->t_err;
729 	}
730 	if (err == -ERESTARTSYS && c->status == Connected) {
731 		p9_debug(P9_DEBUG_MUX, "flushing\n");
732 		sigpending = 1;
733 		clear_thread_flag(TIF_SIGPENDING);
734 
735 		if (c->trans_mod->cancel(c, req))
736 			p9_client_flush(c, req);
737 
738 		/* if we received the response anyway, don't signal error */
739 		if (READ_ONCE(req->status) == REQ_STATUS_RCVD)
740 			err = 0;
741 	}
742 recalc_sigpending:
743 	if (sigpending) {
744 		spin_lock_irqsave(&current->sighand->siglock, flags);
745 		recalc_sigpending();
746 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
747 	}
748 	if (err < 0)
749 		goto reterr;
750 
751 	err = p9_check_errors(c, req);
752 	trace_9p_client_res(c, type, req->rc.tag, err);
753 	if (!err)
754 		return req;
755 reterr:
756 	p9_req_put(c, req);
757 	return ERR_PTR(safe_errno(err));
758 }
759 
760 /**
761  * p9_client_zc_rpc - issue a request and wait for a response
762  * @c: client session
763  * @type: type of request
764  * @uidata: destination for zero copy read
765  * @uodata: source for zero copy write
766  * @inlen: read buffer size
767  * @olen: write buffer size
768  * @in_hdrlen: reader header size, This is the size of response protocol data
769  * @fmt: protocol format string (see protocol.c)
770  *
771  * Returns request structure (which client must free using p9_req_put)
772  */
773 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
774 					 struct iov_iter *uidata,
775 					 struct iov_iter *uodata,
776 					 int inlen, int olen, int in_hdrlen,
777 					 const char *fmt, ...)
778 {
779 	va_list ap;
780 	int sigpending, err;
781 	unsigned long flags;
782 	struct p9_req_t *req;
783 
784 	va_start(ap, fmt);
785 	/* We allocate a inline protocol data of only 4k bytes.
786 	 * The actual content is passed in zero-copy fashion.
787 	 */
788 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, P9_ZC_HDR_SZ, fmt, ap);
789 	va_end(ap);
790 	if (IS_ERR(req))
791 		return req;
792 
793 	req->tc.zc = true;
794 	req->rc.zc = true;
795 
796 	if (signal_pending(current)) {
797 		sigpending = 1;
798 		clear_thread_flag(TIF_SIGPENDING);
799 	} else {
800 		sigpending = 0;
801 	}
802 
803 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
804 				       inlen, olen, in_hdrlen);
805 	if (err < 0) {
806 		if (err == -EIO)
807 			c->status = Disconnected;
808 		if (err != -ERESTARTSYS)
809 			goto recalc_sigpending;
810 	}
811 	if (READ_ONCE(req->status) == REQ_STATUS_ERROR) {
812 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
813 		err = req->t_err;
814 	}
815 	if (err == -ERESTARTSYS && c->status == Connected) {
816 		p9_debug(P9_DEBUG_MUX, "flushing\n");
817 		sigpending = 1;
818 		clear_thread_flag(TIF_SIGPENDING);
819 
820 		if (c->trans_mod->cancel(c, req))
821 			p9_client_flush(c, req);
822 
823 		/* if we received the response anyway, don't signal error */
824 		if (READ_ONCE(req->status) == REQ_STATUS_RCVD)
825 			err = 0;
826 	}
827 recalc_sigpending:
828 	if (sigpending) {
829 		spin_lock_irqsave(&current->sighand->siglock, flags);
830 		recalc_sigpending();
831 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
832 	}
833 	if (err < 0)
834 		goto reterr;
835 
836 	err = p9_check_errors(c, req);
837 	trace_9p_client_res(c, type, req->rc.tag, err);
838 	if (!err)
839 		return req;
840 reterr:
841 	p9_req_put(c, req);
842 	return ERR_PTR(safe_errno(err));
843 }
844 
845 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
846 {
847 	int ret;
848 	struct p9_fid *fid;
849 
850 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
851 	fid = kzalloc(sizeof(*fid), GFP_KERNEL);
852 	if (!fid)
853 		return NULL;
854 
855 	fid->mode = -1;
856 	fid->uid = current_fsuid();
857 	fid->clnt = clnt;
858 	refcount_set(&fid->count, 1);
859 
860 	idr_preload(GFP_KERNEL);
861 	spin_lock_irq(&clnt->lock);
862 	ret = idr_alloc_u32(&clnt->fids, fid, &fid->fid, P9_NOFID - 1,
863 			    GFP_NOWAIT);
864 	spin_unlock_irq(&clnt->lock);
865 	idr_preload_end();
866 	if (!ret) {
867 		trace_9p_fid_ref(fid, P9_FID_REF_CREATE);
868 		return fid;
869 	}
870 
871 	kfree(fid);
872 	return NULL;
873 }
874 
875 static void p9_fid_destroy(struct p9_fid *fid)
876 {
877 	struct p9_client *clnt;
878 	unsigned long flags;
879 
880 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
881 	trace_9p_fid_ref(fid, P9_FID_REF_DESTROY);
882 	clnt = fid->clnt;
883 	spin_lock_irqsave(&clnt->lock, flags);
884 	idr_remove(&clnt->fids, fid->fid);
885 	spin_unlock_irqrestore(&clnt->lock, flags);
886 	kfree(fid->rdir);
887 	kfree(fid);
888 }
889 
890 /* We also need to export tracepoint symbols for tracepoint_enabled() */
891 EXPORT_TRACEPOINT_SYMBOL(9p_fid_ref);
892 
893 void do_trace_9p_fid_get(struct p9_fid *fid)
894 {
895 	trace_9p_fid_ref(fid, P9_FID_REF_GET);
896 }
897 EXPORT_SYMBOL(do_trace_9p_fid_get);
898 
899 void do_trace_9p_fid_put(struct p9_fid *fid)
900 {
901 	trace_9p_fid_ref(fid, P9_FID_REF_PUT);
902 }
903 EXPORT_SYMBOL(do_trace_9p_fid_put);
904 
905 static int p9_client_version(struct p9_client *c)
906 {
907 	int err;
908 	struct p9_req_t *req;
909 	char *version = NULL;
910 	int msize;
911 
912 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
913 		 c->msize, c->proto_version);
914 
915 	switch (c->proto_version) {
916 	case p9_proto_2000L:
917 		req = p9_client_rpc(c, P9_TVERSION, "ds",
918 				    c->msize, "9P2000.L");
919 		break;
920 	case p9_proto_2000u:
921 		req = p9_client_rpc(c, P9_TVERSION, "ds",
922 				    c->msize, "9P2000.u");
923 		break;
924 	case p9_proto_legacy:
925 		req = p9_client_rpc(c, P9_TVERSION, "ds",
926 				    c->msize, "9P2000");
927 		break;
928 	default:
929 		return -EINVAL;
930 	}
931 
932 	if (IS_ERR(req))
933 		return PTR_ERR(req);
934 
935 	err = p9pdu_readf(&req->rc, c->proto_version, "ds", &msize, &version);
936 	if (err) {
937 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
938 		trace_9p_protocol_dump(c, &req->rc);
939 		goto error;
940 	}
941 
942 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
943 	if (!strncmp(version, "9P2000.L", 8)) {
944 		c->proto_version = p9_proto_2000L;
945 	} else if (!strncmp(version, "9P2000.u", 8)) {
946 		c->proto_version = p9_proto_2000u;
947 	} else if (!strncmp(version, "9P2000", 6)) {
948 		c->proto_version = p9_proto_legacy;
949 	} else {
950 		p9_debug(P9_DEBUG_ERROR,
951 			 "server returned an unknown version: %s\n", version);
952 		err = -EREMOTEIO;
953 		goto error;
954 	}
955 
956 	if (msize < 4096) {
957 		p9_debug(P9_DEBUG_ERROR,
958 			 "server returned a msize < 4096: %d\n", msize);
959 		err = -EREMOTEIO;
960 		goto error;
961 	}
962 	if (msize < c->msize)
963 		c->msize = msize;
964 
965 error:
966 	kfree(version);
967 	p9_req_put(c, req);
968 
969 	return err;
970 }
971 
972 struct p9_client *p9_client_create(const char *dev_name, char *options)
973 {
974 	int err;
975 	struct p9_client *clnt;
976 	char *client_id;
977 
978 	clnt = kmalloc(sizeof(*clnt), GFP_KERNEL);
979 	if (!clnt)
980 		return ERR_PTR(-ENOMEM);
981 
982 	clnt->trans_mod = NULL;
983 	clnt->trans = NULL;
984 	clnt->fcall_cache = NULL;
985 
986 	client_id = utsname()->nodename;
987 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
988 
989 	spin_lock_init(&clnt->lock);
990 	idr_init(&clnt->fids);
991 	idr_init(&clnt->reqs);
992 
993 	err = parse_opts(options, clnt);
994 	if (err < 0)
995 		goto free_client;
996 
997 	if (!clnt->trans_mod)
998 		clnt->trans_mod = v9fs_get_default_trans();
999 
1000 	if (!clnt->trans_mod) {
1001 		err = -EPROTONOSUPPORT;
1002 		p9_debug(P9_DEBUG_ERROR,
1003 			 "No transport defined or default transport\n");
1004 		goto free_client;
1005 	}
1006 
1007 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
1008 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
1009 
1010 	err = clnt->trans_mod->create(clnt, dev_name, options);
1011 	if (err)
1012 		goto put_trans;
1013 
1014 	if (clnt->msize > clnt->trans_mod->maxsize) {
1015 		clnt->msize = clnt->trans_mod->maxsize;
1016 		pr_info("Limiting 'msize' to %d as this is the maximum "
1017 			"supported by transport %s\n",
1018 			clnt->msize, clnt->trans_mod->name
1019 		);
1020 	}
1021 
1022 	if (clnt->msize < 4096) {
1023 		p9_debug(P9_DEBUG_ERROR,
1024 			 "Please specify a msize of at least 4k\n");
1025 		err = -EINVAL;
1026 		goto close_trans;
1027 	}
1028 
1029 	err = p9_client_version(clnt);
1030 	if (err)
1031 		goto close_trans;
1032 
1033 	/* P9_HDRSZ + 4 is the smallest packet header we can have that is
1034 	 * followed by data accessed from userspace by read
1035 	 */
1036 	clnt->fcall_cache =
1037 		kmem_cache_create_usercopy("9p-fcall-cache", clnt->msize,
1038 					   0, 0, P9_HDRSZ + 4,
1039 					   clnt->msize - (P9_HDRSZ + 4),
1040 					   NULL);
1041 
1042 	return clnt;
1043 
1044 close_trans:
1045 	clnt->trans_mod->close(clnt);
1046 put_trans:
1047 	v9fs_put_trans(clnt->trans_mod);
1048 free_client:
1049 	kfree(clnt);
1050 	return ERR_PTR(err);
1051 }
1052 EXPORT_SYMBOL(p9_client_create);
1053 
1054 void p9_client_destroy(struct p9_client *clnt)
1055 {
1056 	struct p9_fid *fid;
1057 	int id;
1058 
1059 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1060 
1061 	if (clnt->trans_mod)
1062 		clnt->trans_mod->close(clnt);
1063 
1064 	v9fs_put_trans(clnt->trans_mod);
1065 
1066 	idr_for_each_entry(&clnt->fids, fid, id) {
1067 		pr_info("Found fid %d not clunked\n", fid->fid);
1068 		p9_fid_destroy(fid);
1069 	}
1070 
1071 	p9_tag_cleanup(clnt);
1072 
1073 	kmem_cache_destroy(clnt->fcall_cache);
1074 	kfree(clnt);
1075 }
1076 EXPORT_SYMBOL(p9_client_destroy);
1077 
1078 void p9_client_disconnect(struct p9_client *clnt)
1079 {
1080 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1081 	clnt->status = Disconnected;
1082 }
1083 EXPORT_SYMBOL(p9_client_disconnect);
1084 
1085 void p9_client_begin_disconnect(struct p9_client *clnt)
1086 {
1087 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1088 	clnt->status = BeginDisconnect;
1089 }
1090 EXPORT_SYMBOL(p9_client_begin_disconnect);
1091 
1092 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1093 				const char *uname, kuid_t n_uname,
1094 				const char *aname)
1095 {
1096 	int err;
1097 	struct p9_req_t *req;
1098 	struct p9_fid *fid;
1099 	struct p9_qid qid;
1100 
1101 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1102 		 afid ? afid->fid : -1, uname, aname);
1103 	fid = p9_fid_create(clnt);
1104 	if (!fid) {
1105 		err = -ENOMEM;
1106 		goto error;
1107 	}
1108 	fid->uid = n_uname;
1109 
1110 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
1111 			    afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
1112 	if (IS_ERR(req)) {
1113 		err = PTR_ERR(req);
1114 		goto error;
1115 	}
1116 
1117 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", &qid);
1118 	if (err) {
1119 		trace_9p_protocol_dump(clnt, &req->rc);
1120 		p9_req_put(clnt, req);
1121 		goto error;
1122 	}
1123 
1124 	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
1125 		 qid.type, qid.path, qid.version);
1126 
1127 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1128 
1129 	p9_req_put(clnt, req);
1130 	return fid;
1131 
1132 error:
1133 	if (fid)
1134 		p9_fid_destroy(fid);
1135 	return ERR_PTR(err);
1136 }
1137 EXPORT_SYMBOL(p9_client_attach);
1138 
1139 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
1140 			      const unsigned char * const *wnames, int clone)
1141 {
1142 	int err;
1143 	struct p9_client *clnt;
1144 	struct p9_fid *fid;
1145 	struct p9_qid *wqids;
1146 	struct p9_req_t *req;
1147 	u16 nwqids, count;
1148 
1149 	wqids = NULL;
1150 	clnt = oldfid->clnt;
1151 	if (clone) {
1152 		fid = p9_fid_create(clnt);
1153 		if (!fid) {
1154 			err = -ENOMEM;
1155 			goto error;
1156 		}
1157 
1158 		fid->uid = oldfid->uid;
1159 	} else {
1160 		fid = oldfid;
1161 	}
1162 
1163 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1164 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1165 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1166 			    nwname, wnames);
1167 	if (IS_ERR(req)) {
1168 		err = PTR_ERR(req);
1169 		goto error;
1170 	}
1171 
1172 	err = p9pdu_readf(&req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1173 	if (err) {
1174 		trace_9p_protocol_dump(clnt, &req->rc);
1175 		p9_req_put(clnt, req);
1176 		goto clunk_fid;
1177 	}
1178 	p9_req_put(clnt, req);
1179 
1180 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1181 
1182 	if (nwqids != nwname) {
1183 		err = -ENOENT;
1184 		goto clunk_fid;
1185 	}
1186 
1187 	for (count = 0; count < nwqids; count++)
1188 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1189 			 count, wqids[count].type,
1190 			 wqids[count].path,
1191 			 wqids[count].version);
1192 
1193 	if (nwname)
1194 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1195 	else
1196 		memmove(&fid->qid, &oldfid->qid, sizeof(struct p9_qid));
1197 
1198 	kfree(wqids);
1199 	return fid;
1200 
1201 clunk_fid:
1202 	kfree(wqids);
1203 	p9_fid_put(fid);
1204 	fid = NULL;
1205 
1206 error:
1207 	if (fid && fid != oldfid)
1208 		p9_fid_destroy(fid);
1209 
1210 	return ERR_PTR(err);
1211 }
1212 EXPORT_SYMBOL(p9_client_walk);
1213 
1214 int p9_client_open(struct p9_fid *fid, int mode)
1215 {
1216 	int err;
1217 	struct p9_client *clnt;
1218 	struct p9_req_t *req;
1219 	struct p9_qid qid;
1220 	int iounit;
1221 
1222 	clnt = fid->clnt;
1223 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1224 		 p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1225 
1226 	if (fid->mode != -1)
1227 		return -EINVAL;
1228 
1229 	if (p9_is_proto_dotl(clnt))
1230 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode & P9L_MODE_MASK);
1231 	else
1232 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode & P9L_MODE_MASK);
1233 	if (IS_ERR(req)) {
1234 		err = PTR_ERR(req);
1235 		goto error;
1236 	}
1237 
1238 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1239 	if (err) {
1240 		trace_9p_protocol_dump(clnt, &req->rc);
1241 		goto free_and_error;
1242 	}
1243 
1244 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1245 		 p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1246 		 qid.path, qid.version, iounit);
1247 
1248 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1249 	fid->mode = mode;
1250 	fid->iounit = iounit;
1251 
1252 free_and_error:
1253 	p9_req_put(clnt, req);
1254 error:
1255 	return err;
1256 }
1257 EXPORT_SYMBOL(p9_client_open);
1258 
1259 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags,
1260 			  u32 mode, kgid_t gid, struct p9_qid *qid)
1261 {
1262 	int err;
1263 	struct p9_client *clnt;
1264 	struct p9_req_t *req;
1265 	int iounit;
1266 
1267 	p9_debug(P9_DEBUG_9P,
1268 		 ">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1269 		 ofid->fid, name, flags, mode,
1270 		 from_kgid(&init_user_ns, gid));
1271 	clnt = ofid->clnt;
1272 
1273 	if (ofid->mode != -1)
1274 		return -EINVAL;
1275 
1276 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1277 			    mode & P9L_MODE_MASK, gid);
1278 	if (IS_ERR(req)) {
1279 		err = PTR_ERR(req);
1280 		goto error;
1281 	}
1282 
1283 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", qid, &iounit);
1284 	if (err) {
1285 		trace_9p_protocol_dump(clnt, &req->rc);
1286 		goto free_and_error;
1287 	}
1288 
1289 	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1290 		 qid->type, qid->path, qid->version, iounit);
1291 
1292 	memmove(&ofid->qid, qid, sizeof(struct p9_qid));
1293 	ofid->mode = flags;
1294 	ofid->iounit = iounit;
1295 
1296 free_and_error:
1297 	p9_req_put(clnt, req);
1298 error:
1299 	return err;
1300 }
1301 EXPORT_SYMBOL(p9_client_create_dotl);
1302 
1303 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1304 		     char *extension)
1305 {
1306 	int err;
1307 	struct p9_client *clnt;
1308 	struct p9_req_t *req;
1309 	struct p9_qid qid;
1310 	int iounit;
1311 
1312 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1313 		 fid->fid, name, perm, mode);
1314 	clnt = fid->clnt;
1315 
1316 	if (fid->mode != -1)
1317 		return -EINVAL;
1318 
1319 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1320 			    mode & P9L_MODE_MASK, extension);
1321 	if (IS_ERR(req)) {
1322 		err = PTR_ERR(req);
1323 		goto error;
1324 	}
1325 
1326 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1327 	if (err) {
1328 		trace_9p_protocol_dump(clnt, &req->rc);
1329 		goto free_and_error;
1330 	}
1331 
1332 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1333 		 qid.type, qid.path, qid.version, iounit);
1334 
1335 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1336 	fid->mode = mode;
1337 	fid->iounit = iounit;
1338 
1339 free_and_error:
1340 	p9_req_put(clnt, req);
1341 error:
1342 	return err;
1343 }
1344 EXPORT_SYMBOL(p9_client_fcreate);
1345 
1346 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1347 		      const char *symtgt, kgid_t gid, struct p9_qid *qid)
1348 {
1349 	int err;
1350 	struct p9_client *clnt;
1351 	struct p9_req_t *req;
1352 
1353 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1354 		 dfid->fid, name, symtgt);
1355 	clnt = dfid->clnt;
1356 
1357 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1358 			    gid);
1359 	if (IS_ERR(req)) {
1360 		err = PTR_ERR(req);
1361 		goto error;
1362 	}
1363 
1364 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
1365 	if (err) {
1366 		trace_9p_protocol_dump(clnt, &req->rc);
1367 		goto free_and_error;
1368 	}
1369 
1370 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1371 		 qid->type, qid->path, qid->version);
1372 
1373 free_and_error:
1374 	p9_req_put(clnt, req);
1375 error:
1376 	return err;
1377 }
1378 EXPORT_SYMBOL(p9_client_symlink);
1379 
1380 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1381 {
1382 	struct p9_client *clnt;
1383 	struct p9_req_t *req;
1384 
1385 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1386 		 dfid->fid, oldfid->fid, newname);
1387 	clnt = dfid->clnt;
1388 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1389 			    newname);
1390 	if (IS_ERR(req))
1391 		return PTR_ERR(req);
1392 
1393 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1394 	p9_req_put(clnt, req);
1395 	return 0;
1396 }
1397 EXPORT_SYMBOL(p9_client_link);
1398 
1399 int p9_client_fsync(struct p9_fid *fid, int datasync)
1400 {
1401 	int err = 0;
1402 	struct p9_client *clnt;
1403 	struct p9_req_t *req;
1404 
1405 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1406 		 fid->fid, datasync);
1407 	clnt = fid->clnt;
1408 
1409 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1410 	if (IS_ERR(req)) {
1411 		err = PTR_ERR(req);
1412 		goto error;
1413 	}
1414 
1415 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1416 
1417 	p9_req_put(clnt, req);
1418 
1419 error:
1420 	return err;
1421 }
1422 EXPORT_SYMBOL(p9_client_fsync);
1423 
1424 int p9_client_clunk(struct p9_fid *fid)
1425 {
1426 	int err = 0;
1427 	struct p9_client *clnt;
1428 	struct p9_req_t *req;
1429 	int retries = 0;
1430 
1431 again:
1432 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n",
1433 		 fid->fid, retries);
1434 	clnt = fid->clnt;
1435 
1436 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1437 	if (IS_ERR(req)) {
1438 		err = PTR_ERR(req);
1439 		goto error;
1440 	}
1441 
1442 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1443 
1444 	p9_req_put(clnt, req);
1445 error:
1446 	/* Fid is not valid even after a failed clunk
1447 	 * If interrupted, retry once then give up and
1448 	 * leak fid until umount.
1449 	 */
1450 	if (err == -ERESTARTSYS) {
1451 		if (retries++ == 0)
1452 			goto again;
1453 	} else {
1454 		p9_fid_destroy(fid);
1455 	}
1456 	return err;
1457 }
1458 EXPORT_SYMBOL(p9_client_clunk);
1459 
1460 int p9_client_remove(struct p9_fid *fid)
1461 {
1462 	int err = 0;
1463 	struct p9_client *clnt;
1464 	struct p9_req_t *req;
1465 
1466 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1467 	clnt = fid->clnt;
1468 
1469 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1470 	if (IS_ERR(req)) {
1471 		err = PTR_ERR(req);
1472 		goto error;
1473 	}
1474 
1475 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1476 
1477 	p9_req_put(clnt, req);
1478 error:
1479 	if (err == -ERESTARTSYS)
1480 		p9_fid_put(fid);
1481 	else
1482 		p9_fid_destroy(fid);
1483 	return err;
1484 }
1485 EXPORT_SYMBOL(p9_client_remove);
1486 
1487 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1488 {
1489 	int err = 0;
1490 	struct p9_req_t *req;
1491 	struct p9_client *clnt;
1492 
1493 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1494 		 dfid->fid, name, flags);
1495 
1496 	clnt = dfid->clnt;
1497 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1498 	if (IS_ERR(req)) {
1499 		err = PTR_ERR(req);
1500 		goto error;
1501 	}
1502 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1503 
1504 	p9_req_put(clnt, req);
1505 error:
1506 	return err;
1507 }
1508 EXPORT_SYMBOL(p9_client_unlinkat);
1509 
1510 int
1511 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1512 {
1513 	int total = 0;
1514 	*err = 0;
1515 
1516 	while (iov_iter_count(to)) {
1517 		int count;
1518 
1519 		count = p9_client_read_once(fid, offset, to, err);
1520 		if (!count || *err)
1521 			break;
1522 		offset += count;
1523 		total += count;
1524 	}
1525 	return total;
1526 }
1527 EXPORT_SYMBOL(p9_client_read);
1528 
1529 int
1530 p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
1531 		    int *err)
1532 {
1533 	struct p9_client *clnt = fid->clnt;
1534 	struct p9_req_t *req;
1535 	int count = iov_iter_count(to);
1536 	int rsize, received, non_zc = 0;
1537 	char *dataptr;
1538 
1539 	*err = 0;
1540 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %zu\n",
1541 		 fid->fid, offset, iov_iter_count(to));
1542 
1543 	rsize = fid->iounit;
1544 	if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1545 		rsize = clnt->msize - P9_IOHDRSZ;
1546 
1547 	if (count < rsize)
1548 		rsize = count;
1549 
1550 	/* Don't bother zerocopy for small IO (< 1024) */
1551 	if (clnt->trans_mod->zc_request && rsize > 1024) {
1552 		/* response header len is 11
1553 		 * PDU Header(7) + IO Size (4)
1554 		 */
1555 		req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1556 				       0, 11, "dqd", fid->fid,
1557 				       offset, rsize);
1558 	} else {
1559 		non_zc = 1;
1560 		req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1561 				    rsize);
1562 	}
1563 	if (IS_ERR(req)) {
1564 		*err = PTR_ERR(req);
1565 		if (!non_zc)
1566 			iov_iter_revert(to, count - iov_iter_count(to));
1567 		return 0;
1568 	}
1569 
1570 	*err = p9pdu_readf(&req->rc, clnt->proto_version,
1571 			   "D", &received, &dataptr);
1572 	if (*err) {
1573 		if (!non_zc)
1574 			iov_iter_revert(to, count - iov_iter_count(to));
1575 		trace_9p_protocol_dump(clnt, &req->rc);
1576 		p9_req_put(clnt, req);
1577 		return 0;
1578 	}
1579 	if (rsize < received) {
1580 		pr_err("bogus RREAD count (%d > %d)\n", received, rsize);
1581 		received = rsize;
1582 	}
1583 
1584 	p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1585 
1586 	if (non_zc) {
1587 		int n = copy_to_iter(dataptr, received, to);
1588 
1589 		if (n != received) {
1590 			*err = -EFAULT;
1591 			p9_req_put(clnt, req);
1592 			return n;
1593 		}
1594 	} else {
1595 		iov_iter_revert(to, count - received - iov_iter_count(to));
1596 	}
1597 	p9_req_put(clnt, req);
1598 	return received;
1599 }
1600 EXPORT_SYMBOL(p9_client_read_once);
1601 
1602 int
1603 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1604 {
1605 	struct p9_client *clnt = fid->clnt;
1606 	struct p9_req_t *req;
1607 	int total = 0;
1608 	*err = 0;
1609 
1610 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n",
1611 		 fid->fid, offset, iov_iter_count(from));
1612 
1613 	while (iov_iter_count(from)) {
1614 		int count = iov_iter_count(from);
1615 		int rsize = fid->iounit;
1616 		int written;
1617 
1618 		if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1619 			rsize = clnt->msize - P9_IOHDRSZ;
1620 
1621 		if (count < rsize)
1622 			rsize = count;
1623 
1624 		/* Don't bother zerocopy for small IO (< 1024) */
1625 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1626 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1627 					       rsize, P9_ZC_HDR_SZ, "dqd",
1628 					       fid->fid, offset, rsize);
1629 		} else {
1630 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1631 					    offset, rsize, from);
1632 		}
1633 		if (IS_ERR(req)) {
1634 			iov_iter_revert(from, count - iov_iter_count(from));
1635 			*err = PTR_ERR(req);
1636 			break;
1637 		}
1638 
1639 		*err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &written);
1640 		if (*err) {
1641 			iov_iter_revert(from, count - iov_iter_count(from));
1642 			trace_9p_protocol_dump(clnt, &req->rc);
1643 			p9_req_put(clnt, req);
1644 			break;
1645 		}
1646 		if (rsize < written) {
1647 			pr_err("bogus RWRITE count (%d > %d)\n", written, rsize);
1648 			written = rsize;
1649 		}
1650 
1651 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1652 
1653 		p9_req_put(clnt, req);
1654 		iov_iter_revert(from, count - written - iov_iter_count(from));
1655 		total += written;
1656 		offset += written;
1657 	}
1658 	return total;
1659 }
1660 EXPORT_SYMBOL(p9_client_write);
1661 
1662 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1663 {
1664 	int err;
1665 	struct p9_client *clnt;
1666 	struct p9_wstat *ret;
1667 	struct p9_req_t *req;
1668 	u16 ignored;
1669 
1670 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1671 
1672 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1673 	if (!ret)
1674 		return ERR_PTR(-ENOMEM);
1675 
1676 	clnt = fid->clnt;
1677 
1678 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1679 	if (IS_ERR(req)) {
1680 		err = PTR_ERR(req);
1681 		goto error;
1682 	}
1683 
1684 	err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
1685 	if (err) {
1686 		trace_9p_protocol_dump(clnt, &req->rc);
1687 		p9_req_put(clnt, req);
1688 		goto error;
1689 	}
1690 
1691 	p9_debug(P9_DEBUG_9P,
1692 		 "<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1693 		 "<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1694 		 "<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1695 		 "<<<    uid=%d gid=%d n_muid=%d\n",
1696 		 ret->size, ret->type, ret->dev, ret->qid.type, ret->qid.path,
1697 		 ret->qid.version, ret->mode,
1698 		 ret->atime, ret->mtime, ret->length,
1699 		 ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1700 		 from_kuid(&init_user_ns, ret->n_uid),
1701 		 from_kgid(&init_user_ns, ret->n_gid),
1702 		 from_kuid(&init_user_ns, ret->n_muid));
1703 
1704 	p9_req_put(clnt, req);
1705 	return ret;
1706 
1707 error:
1708 	kfree(ret);
1709 	return ERR_PTR(err);
1710 }
1711 EXPORT_SYMBOL(p9_client_stat);
1712 
1713 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1714 					    u64 request_mask)
1715 {
1716 	int err;
1717 	struct p9_client *clnt;
1718 	struct p9_stat_dotl *ret;
1719 	struct p9_req_t *req;
1720 
1721 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1722 		 fid->fid, request_mask);
1723 
1724 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1725 	if (!ret)
1726 		return ERR_PTR(-ENOMEM);
1727 
1728 	clnt = fid->clnt;
1729 
1730 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1731 	if (IS_ERR(req)) {
1732 		err = PTR_ERR(req);
1733 		goto error;
1734 	}
1735 
1736 	err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
1737 	if (err) {
1738 		trace_9p_protocol_dump(clnt, &req->rc);
1739 		p9_req_put(clnt, req);
1740 		goto error;
1741 	}
1742 
1743 	p9_debug(P9_DEBUG_9P, "<<< RGETATTR st_result_mask=%lld\n"
1744 		 "<<< qid=%x.%llx.%x\n"
1745 		 "<<< st_mode=%8.8x st_nlink=%llu\n"
1746 		 "<<< st_uid=%d st_gid=%d\n"
1747 		 "<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1748 		 "<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1749 		 "<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1750 		 "<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1751 		 "<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1752 		 "<<< st_gen=%lld st_data_version=%lld\n",
1753 		 ret->st_result_mask,
1754 		 ret->qid.type, ret->qid.path, ret->qid.version,
1755 		 ret->st_mode, ret->st_nlink,
1756 		 from_kuid(&init_user_ns, ret->st_uid),
1757 		 from_kgid(&init_user_ns, ret->st_gid),
1758 		 ret->st_rdev, ret->st_size, ret->st_blksize, ret->st_blocks,
1759 		 ret->st_atime_sec, ret->st_atime_nsec,
1760 		 ret->st_mtime_sec, ret->st_mtime_nsec,
1761 		 ret->st_ctime_sec, ret->st_ctime_nsec,
1762 		 ret->st_btime_sec, ret->st_btime_nsec,
1763 		 ret->st_gen, ret->st_data_version);
1764 
1765 	p9_req_put(clnt, req);
1766 	return ret;
1767 
1768 error:
1769 	kfree(ret);
1770 	return ERR_PTR(err);
1771 }
1772 EXPORT_SYMBOL(p9_client_getattr_dotl);
1773 
1774 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1775 {
1776 	int ret;
1777 
1778 	/* NOTE: size shouldn't include its own length */
1779 	/* size[2] type[2] dev[4] qid[13] */
1780 	/* mode[4] atime[4] mtime[4] length[8]*/
1781 	/* name[s] uid[s] gid[s] muid[s] */
1782 	ret = 2 + 4 + 13 + 4 + 4 + 4 + 8 + 2 + 2 + 2 + 2;
1783 
1784 	if (wst->name)
1785 		ret += strlen(wst->name);
1786 	if (wst->uid)
1787 		ret += strlen(wst->uid);
1788 	if (wst->gid)
1789 		ret += strlen(wst->gid);
1790 	if (wst->muid)
1791 		ret += strlen(wst->muid);
1792 
1793 	if (proto_version == p9_proto_2000u ||
1794 	    proto_version == p9_proto_2000L) {
1795 		/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1796 		ret += 2 + 4 + 4 + 4;
1797 		if (wst->extension)
1798 			ret += strlen(wst->extension);
1799 	}
1800 
1801 	return ret;
1802 }
1803 
1804 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1805 {
1806 	int err = 0;
1807 	struct p9_req_t *req;
1808 	struct p9_client *clnt;
1809 
1810 	clnt = fid->clnt;
1811 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1812 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n",
1813 		 fid->fid);
1814 	p9_debug(P9_DEBUG_9P,
1815 		 "     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1816 		 "     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1817 		 "     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1818 		 "     uid=%d gid=%d n_muid=%d\n",
1819 		 wst->size, wst->type, wst->dev, wst->qid.type,
1820 		 wst->qid.path, wst->qid.version,
1821 		 wst->mode, wst->atime, wst->mtime, wst->length,
1822 		 wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1823 		 from_kuid(&init_user_ns, wst->n_uid),
1824 		 from_kgid(&init_user_ns, wst->n_gid),
1825 		 from_kuid(&init_user_ns, wst->n_muid));
1826 
1827 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS",
1828 			    fid->fid, wst->size + 2, wst);
1829 	if (IS_ERR(req)) {
1830 		err = PTR_ERR(req);
1831 		goto error;
1832 	}
1833 
1834 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1835 
1836 	p9_req_put(clnt, req);
1837 error:
1838 	return err;
1839 }
1840 EXPORT_SYMBOL(p9_client_wstat);
1841 
1842 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1843 {
1844 	int err = 0;
1845 	struct p9_req_t *req;
1846 	struct p9_client *clnt;
1847 
1848 	clnt = fid->clnt;
1849 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1850 	p9_debug(P9_DEBUG_9P, "    valid=%x mode=%x uid=%d gid=%d size=%lld\n",
1851 		 p9attr->valid, p9attr->mode,
1852 		 from_kuid(&init_user_ns, p9attr->uid),
1853 		 from_kgid(&init_user_ns, p9attr->gid),
1854 		 p9attr->size);
1855 	p9_debug(P9_DEBUG_9P, "    atime_sec=%lld atime_nsec=%lld\n",
1856 		 p9attr->atime_sec, p9attr->atime_nsec);
1857 	p9_debug(P9_DEBUG_9P, "    mtime_sec=%lld mtime_nsec=%lld\n",
1858 		 p9attr->mtime_sec, p9attr->mtime_nsec);
1859 
1860 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1861 
1862 	if (IS_ERR(req)) {
1863 		err = PTR_ERR(req);
1864 		goto error;
1865 	}
1866 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1867 	p9_req_put(clnt, req);
1868 error:
1869 	return err;
1870 }
1871 EXPORT_SYMBOL(p9_client_setattr);
1872 
1873 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1874 {
1875 	int err;
1876 	struct p9_req_t *req;
1877 	struct p9_client *clnt;
1878 
1879 	clnt = fid->clnt;
1880 
1881 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1882 
1883 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1884 	if (IS_ERR(req)) {
1885 		err = PTR_ERR(req);
1886 		goto error;
1887 	}
1888 
1889 	err = p9pdu_readf(&req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1890 			  &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1891 			  &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1892 	if (err) {
1893 		trace_9p_protocol_dump(clnt, &req->rc);
1894 		p9_req_put(clnt, req);
1895 		goto error;
1896 	}
1897 
1898 	p9_debug(P9_DEBUG_9P,
1899 		 "<<< RSTATFS fid %d type 0x%x bsize %u blocks %llu bfree %llu bavail %llu files %llu ffree %llu fsid %llu namelen %u\n",
1900 		 fid->fid, sb->type, sb->bsize, sb->blocks, sb->bfree,
1901 		 sb->bavail, sb->files, sb->ffree, sb->fsid, sb->namelen);
1902 
1903 	p9_req_put(clnt, req);
1904 error:
1905 	return err;
1906 }
1907 EXPORT_SYMBOL(p9_client_statfs);
1908 
1909 int p9_client_rename(struct p9_fid *fid,
1910 		     struct p9_fid *newdirfid, const char *name)
1911 {
1912 	int err = 0;
1913 	struct p9_req_t *req;
1914 	struct p9_client *clnt;
1915 
1916 	clnt = fid->clnt;
1917 
1918 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1919 		 fid->fid, newdirfid->fid, name);
1920 
1921 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1922 			    newdirfid->fid, name);
1923 	if (IS_ERR(req)) {
1924 		err = PTR_ERR(req);
1925 		goto error;
1926 	}
1927 
1928 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1929 
1930 	p9_req_put(clnt, req);
1931 error:
1932 	return err;
1933 }
1934 EXPORT_SYMBOL(p9_client_rename);
1935 
1936 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
1937 		       struct p9_fid *newdirfid, const char *new_name)
1938 {
1939 	int err = 0;
1940 	struct p9_req_t *req;
1941 	struct p9_client *clnt;
1942 
1943 	clnt = olddirfid->clnt;
1944 
1945 	p9_debug(P9_DEBUG_9P,
1946 		 ">>> TRENAMEAT olddirfid %d old name %s newdirfid %d new name %s\n",
1947 		 olddirfid->fid, old_name, newdirfid->fid, new_name);
1948 
1949 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
1950 			    old_name, newdirfid->fid, new_name);
1951 	if (IS_ERR(req)) {
1952 		err = PTR_ERR(req);
1953 		goto error;
1954 	}
1955 
1956 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
1957 		 newdirfid->fid, new_name);
1958 
1959 	p9_req_put(clnt, req);
1960 error:
1961 	return err;
1962 }
1963 EXPORT_SYMBOL(p9_client_renameat);
1964 
1965 /* An xattrwalk without @attr_name gives the fid for the lisxattr namespace
1966  */
1967 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
1968 				   const char *attr_name, u64 *attr_size)
1969 {
1970 	int err;
1971 	struct p9_req_t *req;
1972 	struct p9_client *clnt;
1973 	struct p9_fid *attr_fid;
1974 
1975 	clnt = file_fid->clnt;
1976 	attr_fid = p9_fid_create(clnt);
1977 	if (!attr_fid) {
1978 		err = -ENOMEM;
1979 		goto error;
1980 	}
1981 	p9_debug(P9_DEBUG_9P,
1982 		 ">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
1983 		 file_fid->fid, attr_fid->fid, attr_name);
1984 
1985 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
1986 			    file_fid->fid, attr_fid->fid, attr_name);
1987 	if (IS_ERR(req)) {
1988 		err = PTR_ERR(req);
1989 		goto error;
1990 	}
1991 	err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
1992 	if (err) {
1993 		trace_9p_protocol_dump(clnt, &req->rc);
1994 		p9_req_put(clnt, req);
1995 		goto clunk_fid;
1996 	}
1997 	p9_req_put(clnt, req);
1998 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
1999 		 attr_fid->fid, *attr_size);
2000 	return attr_fid;
2001 clunk_fid:
2002 	p9_fid_put(attr_fid);
2003 	attr_fid = NULL;
2004 error:
2005 	if (attr_fid && attr_fid != file_fid)
2006 		p9_fid_destroy(attr_fid);
2007 
2008 	return ERR_PTR(err);
2009 }
2010 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
2011 
2012 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
2013 			  u64 attr_size, int flags)
2014 {
2015 	int err = 0;
2016 	struct p9_req_t *req;
2017 	struct p9_client *clnt;
2018 
2019 	p9_debug(P9_DEBUG_9P,
2020 		 ">>> TXATTRCREATE fid %d name  %s size %llu flag %d\n",
2021 		 fid->fid, name, attr_size, flags);
2022 	clnt = fid->clnt;
2023 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
2024 			    fid->fid, name, attr_size, flags);
2025 	if (IS_ERR(req)) {
2026 		err = PTR_ERR(req);
2027 		goto error;
2028 	}
2029 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
2030 	p9_req_put(clnt, req);
2031 error:
2032 	return err;
2033 }
2034 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
2035 
2036 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
2037 {
2038 	int err, rsize, non_zc = 0;
2039 	struct p9_client *clnt;
2040 	struct p9_req_t *req;
2041 	char *dataptr;
2042 	struct kvec kv = {.iov_base = data, .iov_len = count};
2043 	struct iov_iter to;
2044 
2045 	iov_iter_kvec(&to, ITER_DEST, &kv, 1, count);
2046 
2047 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
2048 		 fid->fid, offset, count);
2049 
2050 	clnt = fid->clnt;
2051 
2052 	rsize = fid->iounit;
2053 	if (!rsize || rsize > clnt->msize - P9_READDIRHDRSZ)
2054 		rsize = clnt->msize - P9_READDIRHDRSZ;
2055 
2056 	if (count < rsize)
2057 		rsize = count;
2058 
2059 	/* Don't bother zerocopy for small IO (< 1024) */
2060 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2061 		/* response header len is 11
2062 		 * PDU Header(7) + IO Size (4)
2063 		 */
2064 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2065 				       11, "dqd", fid->fid, offset, rsize);
2066 	} else {
2067 		non_zc = 1;
2068 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2069 				    offset, rsize);
2070 	}
2071 	if (IS_ERR(req)) {
2072 		err = PTR_ERR(req);
2073 		goto error;
2074 	}
2075 
2076 	err = p9pdu_readf(&req->rc, clnt->proto_version, "D", &count, &dataptr);
2077 	if (err) {
2078 		trace_9p_protocol_dump(clnt, &req->rc);
2079 		goto free_and_error;
2080 	}
2081 	if (rsize < count) {
2082 		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
2083 		count = rsize;
2084 	}
2085 
2086 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
2087 
2088 	if (non_zc)
2089 		memmove(data, dataptr, count);
2090 
2091 	p9_req_put(clnt, req);
2092 	return count;
2093 
2094 free_and_error:
2095 	p9_req_put(clnt, req);
2096 error:
2097 	return err;
2098 }
2099 EXPORT_SYMBOL(p9_client_readdir);
2100 
2101 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2102 			 dev_t rdev, kgid_t gid, struct p9_qid *qid)
2103 {
2104 	int err;
2105 	struct p9_client *clnt;
2106 	struct p9_req_t *req;
2107 
2108 	clnt = fid->clnt;
2109 	p9_debug(P9_DEBUG_9P,
2110 		 ">>> TMKNOD fid %d name %s mode %d major %d minor %d\n",
2111 		 fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2112 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2113 			    MAJOR(rdev), MINOR(rdev), gid);
2114 	if (IS_ERR(req))
2115 		return PTR_ERR(req);
2116 
2117 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2118 	if (err) {
2119 		trace_9p_protocol_dump(clnt, &req->rc);
2120 		goto error;
2121 	}
2122 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n",
2123 		 qid->type, qid->path, qid->version);
2124 
2125 error:
2126 	p9_req_put(clnt, req);
2127 	return err;
2128 }
2129 EXPORT_SYMBOL(p9_client_mknod_dotl);
2130 
2131 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2132 			 kgid_t gid, struct p9_qid *qid)
2133 {
2134 	int err;
2135 	struct p9_client *clnt;
2136 	struct p9_req_t *req;
2137 
2138 	clnt = fid->clnt;
2139 	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
2140 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
2141 	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg",
2142 			    fid->fid, name, mode, gid);
2143 	if (IS_ERR(req))
2144 		return PTR_ERR(req);
2145 
2146 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2147 	if (err) {
2148 		trace_9p_protocol_dump(clnt, &req->rc);
2149 		goto error;
2150 	}
2151 	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
2152 		 qid->path, qid->version);
2153 
2154 error:
2155 	p9_req_put(clnt, req);
2156 	return err;
2157 }
2158 EXPORT_SYMBOL(p9_client_mkdir_dotl);
2159 
2160 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
2161 {
2162 	int err;
2163 	struct p9_client *clnt;
2164 	struct p9_req_t *req;
2165 
2166 	clnt = fid->clnt;
2167 	p9_debug(P9_DEBUG_9P,
2168 		 ">>> TLOCK fid %d type %i flags %d start %lld length %lld proc_id %d client_id %s\n",
2169 		 fid->fid, flock->type, flock->flags, flock->start,
2170 		 flock->length, flock->proc_id, flock->client_id);
2171 
2172 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2173 			    flock->flags, flock->start, flock->length,
2174 			    flock->proc_id, flock->client_id);
2175 
2176 	if (IS_ERR(req))
2177 		return PTR_ERR(req);
2178 
2179 	err = p9pdu_readf(&req->rc, clnt->proto_version, "b", status);
2180 	if (err) {
2181 		trace_9p_protocol_dump(clnt, &req->rc);
2182 		goto error;
2183 	}
2184 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2185 error:
2186 	p9_req_put(clnt, req);
2187 	return err;
2188 }
2189 EXPORT_SYMBOL(p9_client_lock_dotl);
2190 
2191 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2192 {
2193 	int err;
2194 	struct p9_client *clnt;
2195 	struct p9_req_t *req;
2196 
2197 	clnt = fid->clnt;
2198 	p9_debug(P9_DEBUG_9P,
2199 		 ">>> TGETLOCK fid %d, type %i start %lld length %lld proc_id %d client_id %s\n",
2200 		 fid->fid, glock->type, glock->start, glock->length,
2201 		 glock->proc_id, glock->client_id);
2202 
2203 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,
2204 			    glock->type, glock->start, glock->length,
2205 			    glock->proc_id, glock->client_id);
2206 
2207 	if (IS_ERR(req))
2208 		return PTR_ERR(req);
2209 
2210 	err = p9pdu_readf(&req->rc, clnt->proto_version, "bqqds", &glock->type,
2211 			  &glock->start, &glock->length, &glock->proc_id,
2212 			  &glock->client_id);
2213 	if (err) {
2214 		trace_9p_protocol_dump(clnt, &req->rc);
2215 		goto error;
2216 	}
2217 	p9_debug(P9_DEBUG_9P,
2218 		 "<<< RGETLOCK type %i start %lld length %lld proc_id %d client_id %s\n",
2219 		 glock->type, glock->start, glock->length,
2220 		 glock->proc_id, glock->client_id);
2221 error:
2222 	p9_req_put(clnt, req);
2223 	return err;
2224 }
2225 EXPORT_SYMBOL(p9_client_getlock_dotl);
2226 
2227 int p9_client_readlink(struct p9_fid *fid, char **target)
2228 {
2229 	int err;
2230 	struct p9_client *clnt;
2231 	struct p9_req_t *req;
2232 
2233 	clnt = fid->clnt;
2234 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2235 
2236 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2237 	if (IS_ERR(req))
2238 		return PTR_ERR(req);
2239 
2240 	err = p9pdu_readf(&req->rc, clnt->proto_version, "s", target);
2241 	if (err) {
2242 		trace_9p_protocol_dump(clnt, &req->rc);
2243 		goto error;
2244 	}
2245 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2246 error:
2247 	p9_req_put(clnt, req);
2248 	return err;
2249 }
2250 EXPORT_SYMBOL(p9_client_readlink);
2251 
2252 int __init p9_client_init(void)
2253 {
2254 	p9_req_cache = KMEM_CACHE(p9_req_t, SLAB_TYPESAFE_BY_RCU);
2255 	return p9_req_cache ? 0 : -ENOMEM;
2256 }
2257 
2258 void __exit p9_client_exit(void)
2259 {
2260 	kmem_cache_destroy(p9_req_cache);
2261 }
2262