xref: /linux/net/9p/client.c (revision 286c171b86ebc693e18b485dde3a3fc470af37bd)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * 9P Client
4  *
5  *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
6  *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
7  */
8 
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 
11 #include <linux/module.h>
12 #include <linux/errno.h>
13 #include <linux/fs.h>
14 #include <linux/poll.h>
15 #include <linux/idr.h>
16 #include <linux/mutex.h>
17 #include <linux/slab.h>
18 #include <linux/sched/signal.h>
19 #include <linux/uaccess.h>
20 #include <linux/uio.h>
21 #include <net/9p/9p.h>
22 #include <linux/parser.h>
23 #include <linux/seq_file.h>
24 #include <net/9p/client.h>
25 #include <net/9p/transport.h>
26 #include "protocol.h"
27 
28 #define CREATE_TRACE_POINTS
29 #include <trace/events/9p.h>
30 
31 #define DEFAULT_MSIZE (128 * 1024)
32 
33 /* Client Option Parsing (code inspired by NFS code)
34  *  - a little lazy - parse all client options
35  */
36 
37 enum {
38 	Opt_msize,
39 	Opt_trans,
40 	Opt_legacy,
41 	Opt_version,
42 	Opt_err,
43 };
44 
45 static const match_table_t tokens = {
46 	{Opt_msize, "msize=%u"},
47 	{Opt_legacy, "noextend"},
48 	{Opt_trans, "trans=%s"},
49 	{Opt_version, "version=%s"},
50 	{Opt_err, NULL},
51 };
52 
53 inline int p9_is_proto_dotl(struct p9_client *clnt)
54 {
55 	return clnt->proto_version == p9_proto_2000L;
56 }
57 EXPORT_SYMBOL(p9_is_proto_dotl);
58 
59 inline int p9_is_proto_dotu(struct p9_client *clnt)
60 {
61 	return clnt->proto_version == p9_proto_2000u;
62 }
63 EXPORT_SYMBOL(p9_is_proto_dotu);
64 
65 int p9_show_client_options(struct seq_file *m, struct p9_client *clnt)
66 {
67 	if (clnt->msize != DEFAULT_MSIZE)
68 		seq_printf(m, ",msize=%u", clnt->msize);
69 	seq_printf(m, ",trans=%s", clnt->trans_mod->name);
70 
71 	switch (clnt->proto_version) {
72 	case p9_proto_legacy:
73 		seq_puts(m, ",noextend");
74 		break;
75 	case p9_proto_2000u:
76 		seq_puts(m, ",version=9p2000.u");
77 		break;
78 	case p9_proto_2000L:
79 		/* Default */
80 		break;
81 	}
82 
83 	if (clnt->trans_mod->show_options)
84 		return clnt->trans_mod->show_options(m, clnt);
85 	return 0;
86 }
87 EXPORT_SYMBOL(p9_show_client_options);
88 
89 /* Some error codes are taken directly from the server replies,
90  * make sure they are valid.
91  */
92 static int safe_errno(int err)
93 {
94 	if (err > 0 || err < -MAX_ERRNO) {
95 		p9_debug(P9_DEBUG_ERROR, "Invalid error code %d\n", err);
96 		return -EPROTO;
97 	}
98 	return err;
99 }
100 
101 /* Interpret mount option for protocol version */
102 static int get_protocol_version(char *s)
103 {
104 	int version = -EINVAL;
105 
106 	if (!strcmp(s, "9p2000")) {
107 		version = p9_proto_legacy;
108 		p9_debug(P9_DEBUG_9P, "Protocol version: Legacy\n");
109 	} else if (!strcmp(s, "9p2000.u")) {
110 		version = p9_proto_2000u;
111 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.u\n");
112 	} else if (!strcmp(s, "9p2000.L")) {
113 		version = p9_proto_2000L;
114 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.L\n");
115 	} else {
116 		pr_info("Unknown protocol version %s\n", s);
117 	}
118 
119 	return version;
120 }
121 
122 /**
123  * parse_opts - parse mount options into client structure
124  * @opts: options string passed from mount
125  * @clnt: existing v9fs client information
126  *
127  * Return 0 upon success, -ERRNO upon failure
128  */
129 
130 static int parse_opts(char *opts, struct p9_client *clnt)
131 {
132 	char *options, *tmp_options;
133 	char *p;
134 	substring_t args[MAX_OPT_ARGS];
135 	int option;
136 	char *s;
137 	int ret = 0;
138 
139 	clnt->proto_version = p9_proto_2000L;
140 	clnt->msize = DEFAULT_MSIZE;
141 
142 	if (!opts)
143 		return 0;
144 
145 	tmp_options = kstrdup(opts, GFP_KERNEL);
146 	if (!tmp_options)
147 		return -ENOMEM;
148 	options = tmp_options;
149 
150 	while ((p = strsep(&options, ",")) != NULL) {
151 		int token, r;
152 
153 		if (!*p)
154 			continue;
155 		token = match_token(p, tokens, args);
156 		switch (token) {
157 		case Opt_msize:
158 			r = match_int(&args[0], &option);
159 			if (r < 0) {
160 				p9_debug(P9_DEBUG_ERROR,
161 					 "integer field, but no integer?\n");
162 				ret = r;
163 				continue;
164 			}
165 			if (option < 4096) {
166 				p9_debug(P9_DEBUG_ERROR,
167 					 "msize should be at least 4k\n");
168 				ret = -EINVAL;
169 				continue;
170 			}
171 			clnt->msize = option;
172 			break;
173 		case Opt_trans:
174 			s = match_strdup(&args[0]);
175 			if (!s) {
176 				ret = -ENOMEM;
177 				p9_debug(P9_DEBUG_ERROR,
178 					 "problem allocating copy of trans arg\n");
179 				goto free_and_return;
180 			}
181 
182 			v9fs_put_trans(clnt->trans_mod);
183 			clnt->trans_mod = v9fs_get_trans_by_name(s);
184 			if (!clnt->trans_mod) {
185 				pr_info("Could not find request transport: %s\n",
186 					s);
187 				ret = -EINVAL;
188 			}
189 			kfree(s);
190 			break;
191 		case Opt_legacy:
192 			clnt->proto_version = p9_proto_legacy;
193 			break;
194 		case Opt_version:
195 			s = match_strdup(&args[0]);
196 			if (!s) {
197 				ret = -ENOMEM;
198 				p9_debug(P9_DEBUG_ERROR,
199 					 "problem allocating copy of version arg\n");
200 				goto free_and_return;
201 			}
202 			r = get_protocol_version(s);
203 			if (r < 0)
204 				ret = r;
205 			else
206 				clnt->proto_version = r;
207 			kfree(s);
208 			break;
209 		default:
210 			continue;
211 		}
212 	}
213 
214 free_and_return:
215 	if (ret)
216 		v9fs_put_trans(clnt->trans_mod);
217 	kfree(tmp_options);
218 	return ret;
219 }
220 
221 static int p9_fcall_init(struct p9_client *c, struct p9_fcall *fc,
222 			 int alloc_msize)
223 {
224 	if (likely(c->fcall_cache) && alloc_msize == c->msize) {
225 		fc->sdata = kmem_cache_alloc(c->fcall_cache, GFP_NOFS);
226 		fc->cache = c->fcall_cache;
227 	} else {
228 		fc->sdata = kmalloc(alloc_msize, GFP_NOFS);
229 		fc->cache = NULL;
230 	}
231 	if (!fc->sdata)
232 		return -ENOMEM;
233 	fc->capacity = alloc_msize;
234 	return 0;
235 }
236 
237 void p9_fcall_fini(struct p9_fcall *fc)
238 {
239 	/* sdata can be NULL for interrupted requests in trans_rdma,
240 	 * and kmem_cache_free does not do NULL-check for us
241 	 */
242 	if (unlikely(!fc->sdata))
243 		return;
244 
245 	if (fc->cache)
246 		kmem_cache_free(fc->cache, fc->sdata);
247 	else
248 		kfree(fc->sdata);
249 }
250 EXPORT_SYMBOL(p9_fcall_fini);
251 
252 static struct kmem_cache *p9_req_cache;
253 
254 /**
255  * p9_tag_alloc - Allocate a new request.
256  * @c: Client session.
257  * @type: Transaction type.
258  * @max_size: Maximum packet size for this request.
259  *
260  * Context: Process context.
261  * Return: Pointer to new request.
262  */
263 static struct p9_req_t *
264 p9_tag_alloc(struct p9_client *c, int8_t type, unsigned int max_size)
265 {
266 	struct p9_req_t *req = kmem_cache_alloc(p9_req_cache, GFP_NOFS);
267 	int alloc_msize = min(c->msize, max_size);
268 	int tag;
269 
270 	if (!req)
271 		return ERR_PTR(-ENOMEM);
272 
273 	if (p9_fcall_init(c, &req->tc, alloc_msize))
274 		goto free_req;
275 	if (p9_fcall_init(c, &req->rc, alloc_msize))
276 		goto free;
277 
278 	p9pdu_reset(&req->tc);
279 	p9pdu_reset(&req->rc);
280 	req->t_err = 0;
281 	req->status = REQ_STATUS_ALLOC;
282 	init_waitqueue_head(&req->wq);
283 	INIT_LIST_HEAD(&req->req_list);
284 
285 	idr_preload(GFP_NOFS);
286 	spin_lock_irq(&c->lock);
287 	if (type == P9_TVERSION)
288 		tag = idr_alloc(&c->reqs, req, P9_NOTAG, P9_NOTAG + 1,
289 				GFP_NOWAIT);
290 	else
291 		tag = idr_alloc(&c->reqs, req, 0, P9_NOTAG, GFP_NOWAIT);
292 	req->tc.tag = tag;
293 	spin_unlock_irq(&c->lock);
294 	idr_preload_end();
295 	if (tag < 0)
296 		goto free;
297 
298 	/* Init ref to two because in the general case there is one ref
299 	 * that is put asynchronously by a writer thread, one ref
300 	 * temporarily given by p9_tag_lookup and put by p9_client_cb
301 	 * in the recv thread, and one ref put by p9_tag_remove in the
302 	 * main thread. The only exception is virtio that does not use
303 	 * p9_tag_lookup but does not have a writer thread either
304 	 * (the write happens synchronously in the request/zc_request
305 	 * callback), so p9_client_cb eats the second ref there
306 	 * as the pointer is duplicated directly by virtqueue_add_sgs()
307 	 */
308 	refcount_set(&req->refcount.refcount, 2);
309 
310 	return req;
311 
312 free:
313 	p9_fcall_fini(&req->tc);
314 	p9_fcall_fini(&req->rc);
315 free_req:
316 	kmem_cache_free(p9_req_cache, req);
317 	return ERR_PTR(-ENOMEM);
318 }
319 
320 /**
321  * p9_tag_lookup - Look up a request by tag.
322  * @c: Client session.
323  * @tag: Transaction ID.
324  *
325  * Context: Any context.
326  * Return: A request, or %NULL if there is no request with that tag.
327  */
328 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
329 {
330 	struct p9_req_t *req;
331 
332 	rcu_read_lock();
333 again:
334 	req = idr_find(&c->reqs, tag);
335 	if (req) {
336 		/* We have to be careful with the req found under rcu_read_lock
337 		 * Thanks to SLAB_TYPESAFE_BY_RCU we can safely try to get the
338 		 * ref again without corrupting other data, then check again
339 		 * that the tag matches once we have the ref
340 		 */
341 		if (!p9_req_try_get(req))
342 			goto again;
343 		if (req->tc.tag != tag) {
344 			p9_req_put(req);
345 			goto again;
346 		}
347 	}
348 	rcu_read_unlock();
349 
350 	return req;
351 }
352 EXPORT_SYMBOL(p9_tag_lookup);
353 
354 /**
355  * p9_tag_remove - Remove a tag.
356  * @c: Client session.
357  * @r: Request of reference.
358  *
359  * Context: Any context.
360  */
361 static int p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
362 {
363 	unsigned long flags;
364 	u16 tag = r->tc.tag;
365 
366 	p9_debug(P9_DEBUG_MUX, "clnt %p req %p tag: %d\n", c, r, tag);
367 	spin_lock_irqsave(&c->lock, flags);
368 	idr_remove(&c->reqs, tag);
369 	spin_unlock_irqrestore(&c->lock, flags);
370 	return p9_req_put(r);
371 }
372 
373 static void p9_req_free(struct kref *ref)
374 {
375 	struct p9_req_t *r = container_of(ref, struct p9_req_t, refcount);
376 
377 	p9_fcall_fini(&r->tc);
378 	p9_fcall_fini(&r->rc);
379 	kmem_cache_free(p9_req_cache, r);
380 }
381 
382 int p9_req_put(struct p9_req_t *r)
383 {
384 	return kref_put(&r->refcount, p9_req_free);
385 }
386 EXPORT_SYMBOL(p9_req_put);
387 
388 /**
389  * p9_tag_cleanup - cleans up tags structure and reclaims resources
390  * @c:  v9fs client struct
391  *
392  * This frees resources associated with the tags structure
393  *
394  */
395 static void p9_tag_cleanup(struct p9_client *c)
396 {
397 	struct p9_req_t *req;
398 	int id;
399 
400 	rcu_read_lock();
401 	idr_for_each_entry(&c->reqs, req, id) {
402 		pr_info("Tag %d still in use\n", id);
403 		if (p9_tag_remove(c, req) == 0)
404 			pr_warn("Packet with tag %d has still references",
405 				req->tc.tag);
406 	}
407 	rcu_read_unlock();
408 }
409 
410 /**
411  * p9_client_cb - call back from transport to client
412  * @c: client state
413  * @req: request received
414  * @status: request status, one of REQ_STATUS_*
415  *
416  */
417 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
418 {
419 	p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc.tag);
420 
421 	/* This barrier is needed to make sure any change made to req before
422 	 * the status change is visible to another thread
423 	 */
424 	smp_wmb();
425 	req->status = status;
426 
427 	wake_up(&req->wq);
428 	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
429 	p9_req_put(req);
430 }
431 EXPORT_SYMBOL(p9_client_cb);
432 
433 /**
434  * p9_parse_header - parse header arguments out of a packet
435  * @pdu: packet to parse
436  * @size: size of packet
437  * @type: type of request
438  * @tag: tag of packet
439  * @rewind: set if we need to rewind offset afterwards
440  */
441 
442 int
443 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type,
444 		int16_t *tag, int rewind)
445 {
446 	s8 r_type;
447 	s16 r_tag;
448 	s32 r_size;
449 	int offset = pdu->offset;
450 	int err;
451 
452 	pdu->offset = 0;
453 
454 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
455 	if (err)
456 		goto rewind_and_exit;
457 
458 	if (type)
459 		*type = r_type;
460 	if (tag)
461 		*tag = r_tag;
462 	if (size)
463 		*size = r_size;
464 
465 	if (pdu->size != r_size || r_size < 7) {
466 		err = -EINVAL;
467 		goto rewind_and_exit;
468 	}
469 
470 	pdu->id = r_type;
471 	pdu->tag = r_tag;
472 
473 	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
474 		 pdu->size, pdu->id, pdu->tag);
475 
476 rewind_and_exit:
477 	if (rewind)
478 		pdu->offset = offset;
479 	return err;
480 }
481 EXPORT_SYMBOL(p9_parse_header);
482 
483 /**
484  * p9_check_errors - check 9p packet for error return and process it
485  * @c: current client instance
486  * @req: request to parse and check for error conditions
487  *
488  * returns error code if one is discovered, otherwise returns 0
489  *
490  * this will have to be more complicated if we have multiple
491  * error packet types
492  */
493 
494 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
495 {
496 	s8 type;
497 	int err;
498 	int ecode;
499 
500 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
501 	if (req->rc.size >= c->msize) {
502 		p9_debug(P9_DEBUG_ERROR,
503 			 "requested packet size too big: %d\n",
504 			 req->rc.size);
505 		return -EIO;
506 	}
507 	/* dump the response from server
508 	 * This should be after check errors which poplulate pdu_fcall.
509 	 */
510 	trace_9p_protocol_dump(c, &req->rc);
511 	if (err) {
512 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
513 		return err;
514 	}
515 	if (type != P9_RERROR && type != P9_RLERROR)
516 		return 0;
517 
518 	if (!p9_is_proto_dotl(c)) {
519 		char *ename;
520 
521 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
522 				  &ename, &ecode);
523 		if (err)
524 			goto out_err;
525 
526 		if (p9_is_proto_dotu(c) && ecode < 512)
527 			err = -ecode;
528 
529 		if (!err) {
530 			err = p9_errstr2errno(ename, strlen(ename));
531 
532 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
533 				 -ecode, ename);
534 		}
535 		kfree(ename);
536 	} else {
537 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
538 		if (err)
539 			goto out_err;
540 		err = -ecode;
541 
542 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
543 	}
544 
545 	return err;
546 
547 out_err:
548 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
549 
550 	return err;
551 }
552 
553 /**
554  * p9_check_zc_errors - check 9p packet for error return and process it
555  * @c: current client instance
556  * @req: request to parse and check for error conditions
557  * @uidata: external buffer containing error
558  * @in_hdrlen: Size of response protocol buffer.
559  *
560  * returns error code if one is discovered, otherwise returns 0
561  *
562  * this will have to be more complicated if we have multiple
563  * error packet types
564  */
565 
566 static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
567 			      struct iov_iter *uidata, int in_hdrlen)
568 {
569 	int err;
570 	int ecode;
571 	s8 type;
572 	char *ename = NULL;
573 
574 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
575 	/* dump the response from server
576 	 * This should be after parse_header which poplulate pdu_fcall.
577 	 */
578 	trace_9p_protocol_dump(c, &req->rc);
579 	if (err) {
580 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
581 		return err;
582 	}
583 
584 	if (type != P9_RERROR && type != P9_RLERROR)
585 		return 0;
586 
587 	if (!p9_is_proto_dotl(c)) {
588 		/* Error is reported in string format */
589 		int len;
590 		/* 7 = header size for RERROR; */
591 		int inline_len = in_hdrlen - 7;
592 
593 		len = req->rc.size - req->rc.offset;
594 		if (len > (P9_ZC_HDR_SZ - 7)) {
595 			err = -EFAULT;
596 			goto out_err;
597 		}
598 
599 		ename = &req->rc.sdata[req->rc.offset];
600 		if (len > inline_len) {
601 			/* We have error in external buffer */
602 			if (!copy_from_iter_full(ename + inline_len,
603 						 len - inline_len, uidata)) {
604 				err = -EFAULT;
605 				goto out_err;
606 			}
607 		}
608 		ename = NULL;
609 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
610 				  &ename, &ecode);
611 		if (err)
612 			goto out_err;
613 
614 		if (p9_is_proto_dotu(c) && ecode < 512)
615 			err = -ecode;
616 
617 		if (!err) {
618 			err = p9_errstr2errno(ename, strlen(ename));
619 
620 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
621 				 -ecode, ename);
622 		}
623 		kfree(ename);
624 	} else {
625 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
626 		err = -ecode;
627 
628 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
629 	}
630 	return err;
631 
632 out_err:
633 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
634 	return err;
635 }
636 
637 static struct p9_req_t *
638 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
639 
640 /**
641  * p9_client_flush - flush (cancel) a request
642  * @c: client state
643  * @oldreq: request to cancel
644  *
645  * This sents a flush for a particular request and links
646  * the flush request to the original request.  The current
647  * code only supports a single flush request although the protocol
648  * allows for multiple flush requests to be sent for a single request.
649  *
650  */
651 
652 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
653 {
654 	struct p9_req_t *req;
655 	s16 oldtag;
656 	int err;
657 
658 	err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
659 	if (err)
660 		return err;
661 
662 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
663 
664 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
665 	if (IS_ERR(req))
666 		return PTR_ERR(req);
667 
668 	/* if we haven't received a response for oldreq,
669 	 * remove it from the list
670 	 */
671 	if (oldreq->status == REQ_STATUS_SENT) {
672 		if (c->trans_mod->cancelled)
673 			c->trans_mod->cancelled(c, oldreq);
674 	}
675 
676 	p9_tag_remove(c, req);
677 	return 0;
678 }
679 
680 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
681 					      int8_t type, int req_size,
682 					      const char *fmt, va_list ap)
683 {
684 	int err;
685 	struct p9_req_t *req;
686 
687 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
688 
689 	/* we allow for any status other than disconnected */
690 	if (c->status == Disconnected)
691 		return ERR_PTR(-EIO);
692 
693 	/* if status is begin_disconnected we allow only clunk request */
694 	if (c->status == BeginDisconnect && type != P9_TCLUNK)
695 		return ERR_PTR(-EIO);
696 
697 	req = p9_tag_alloc(c, type, req_size);
698 	if (IS_ERR(req))
699 		return req;
700 
701 	/* marshall the data */
702 	p9pdu_prepare(&req->tc, req->tc.tag, type);
703 	err = p9pdu_vwritef(&req->tc, c->proto_version, fmt, ap);
704 	if (err)
705 		goto reterr;
706 	p9pdu_finalize(c, &req->tc);
707 	trace_9p_client_req(c, type, req->tc.tag);
708 	return req;
709 reterr:
710 	p9_tag_remove(c, req);
711 	/* We have to put also the 2nd reference as it won't be used */
712 	p9_req_put(req);
713 	return ERR_PTR(err);
714 }
715 
716 /**
717  * p9_client_rpc - issue a request and wait for a response
718  * @c: client session
719  * @type: type of request
720  * @fmt: protocol format string (see protocol.c)
721  *
722  * Returns request structure (which client must free using p9_tag_remove)
723  */
724 
725 static struct p9_req_t *
726 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
727 {
728 	va_list ap;
729 	int sigpending, err;
730 	unsigned long flags;
731 	struct p9_req_t *req;
732 
733 	va_start(ap, fmt);
734 	req = p9_client_prepare_req(c, type, c->msize, fmt, ap);
735 	va_end(ap);
736 	if (IS_ERR(req))
737 		return req;
738 
739 	if (signal_pending(current)) {
740 		sigpending = 1;
741 		clear_thread_flag(TIF_SIGPENDING);
742 	} else {
743 		sigpending = 0;
744 	}
745 
746 	err = c->trans_mod->request(c, req);
747 	if (err < 0) {
748 		/* write won't happen */
749 		p9_req_put(req);
750 		if (err != -ERESTARTSYS && err != -EFAULT)
751 			c->status = Disconnected;
752 		goto recalc_sigpending;
753 	}
754 again:
755 	/* Wait for the response */
756 	err = wait_event_killable(req->wq, req->status >= REQ_STATUS_RCVD);
757 
758 	/* Make sure our req is coherent with regard to updates in other
759 	 * threads - echoes to wmb() in the callback
760 	 */
761 	smp_rmb();
762 
763 	if (err == -ERESTARTSYS && c->status == Connected &&
764 	    type == P9_TFLUSH) {
765 		sigpending = 1;
766 		clear_thread_flag(TIF_SIGPENDING);
767 		goto again;
768 	}
769 
770 	if (req->status == REQ_STATUS_ERROR) {
771 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
772 		err = req->t_err;
773 	}
774 	if (err == -ERESTARTSYS && c->status == Connected) {
775 		p9_debug(P9_DEBUG_MUX, "flushing\n");
776 		sigpending = 1;
777 		clear_thread_flag(TIF_SIGPENDING);
778 
779 		if (c->trans_mod->cancel(c, req))
780 			p9_client_flush(c, req);
781 
782 		/* if we received the response anyway, don't signal error */
783 		if (req->status == REQ_STATUS_RCVD)
784 			err = 0;
785 	}
786 recalc_sigpending:
787 	if (sigpending) {
788 		spin_lock_irqsave(&current->sighand->siglock, flags);
789 		recalc_sigpending();
790 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
791 	}
792 	if (err < 0)
793 		goto reterr;
794 
795 	err = p9_check_errors(c, req);
796 	trace_9p_client_res(c, type, req->rc.tag, err);
797 	if (!err)
798 		return req;
799 reterr:
800 	p9_tag_remove(c, req);
801 	return ERR_PTR(safe_errno(err));
802 }
803 
804 /**
805  * p9_client_zc_rpc - issue a request and wait for a response
806  * @c: client session
807  * @type: type of request
808  * @uidata: destination for zero copy read
809  * @uodata: source for zero copy write
810  * @inlen: read buffer size
811  * @olen: write buffer size
812  * @in_hdrlen: reader header size, This is the size of response protocol data
813  * @fmt: protocol format string (see protocol.c)
814  *
815  * Returns request structure (which client must free using p9_tag_remove)
816  */
817 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
818 					 struct iov_iter *uidata,
819 					 struct iov_iter *uodata,
820 					 int inlen, int olen, int in_hdrlen,
821 					 const char *fmt, ...)
822 {
823 	va_list ap;
824 	int sigpending, err;
825 	unsigned long flags;
826 	struct p9_req_t *req;
827 
828 	va_start(ap, fmt);
829 	/* We allocate a inline protocol data of only 4k bytes.
830 	 * The actual content is passed in zero-copy fashion.
831 	 */
832 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, fmt, ap);
833 	va_end(ap);
834 	if (IS_ERR(req))
835 		return req;
836 
837 	if (signal_pending(current)) {
838 		sigpending = 1;
839 		clear_thread_flag(TIF_SIGPENDING);
840 	} else {
841 		sigpending = 0;
842 	}
843 
844 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
845 				       inlen, olen, in_hdrlen);
846 	if (err < 0) {
847 		if (err == -EIO)
848 			c->status = Disconnected;
849 		if (err != -ERESTARTSYS)
850 			goto recalc_sigpending;
851 	}
852 	if (req->status == REQ_STATUS_ERROR) {
853 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
854 		err = req->t_err;
855 	}
856 	if (err == -ERESTARTSYS && c->status == Connected) {
857 		p9_debug(P9_DEBUG_MUX, "flushing\n");
858 		sigpending = 1;
859 		clear_thread_flag(TIF_SIGPENDING);
860 
861 		if (c->trans_mod->cancel(c, req))
862 			p9_client_flush(c, req);
863 
864 		/* if we received the response anyway, don't signal error */
865 		if (req->status == REQ_STATUS_RCVD)
866 			err = 0;
867 	}
868 recalc_sigpending:
869 	if (sigpending) {
870 		spin_lock_irqsave(&current->sighand->siglock, flags);
871 		recalc_sigpending();
872 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
873 	}
874 	if (err < 0)
875 		goto reterr;
876 
877 	err = p9_check_zc_errors(c, req, uidata, in_hdrlen);
878 	trace_9p_client_res(c, type, req->rc.tag, err);
879 	if (!err)
880 		return req;
881 reterr:
882 	p9_tag_remove(c, req);
883 	return ERR_PTR(safe_errno(err));
884 }
885 
886 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
887 {
888 	int ret;
889 	struct p9_fid *fid;
890 
891 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
892 	fid = kmalloc(sizeof(*fid), GFP_KERNEL);
893 	if (!fid)
894 		return NULL;
895 
896 	memset(&fid->qid, 0, sizeof(fid->qid));
897 	fid->mode = -1;
898 	fid->uid = current_fsuid();
899 	fid->clnt = clnt;
900 	fid->rdir = NULL;
901 	fid->fid = 0;
902 	refcount_set(&fid->count, 1);
903 
904 	idr_preload(GFP_KERNEL);
905 	spin_lock_irq(&clnt->lock);
906 	ret = idr_alloc_u32(&clnt->fids, fid, &fid->fid, P9_NOFID - 1,
907 			    GFP_NOWAIT);
908 	spin_unlock_irq(&clnt->lock);
909 	idr_preload_end();
910 	if (!ret) {
911 		trace_9p_fid_ref(fid, P9_FID_REF_CREATE);
912 		return fid;
913 	}
914 
915 	kfree(fid);
916 	return NULL;
917 }
918 
919 static void p9_fid_destroy(struct p9_fid *fid)
920 {
921 	struct p9_client *clnt;
922 	unsigned long flags;
923 
924 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
925 	trace_9p_fid_ref(fid, P9_FID_REF_DESTROY);
926 	clnt = fid->clnt;
927 	spin_lock_irqsave(&clnt->lock, flags);
928 	idr_remove(&clnt->fids, fid->fid);
929 	spin_unlock_irqrestore(&clnt->lock, flags);
930 	kfree(fid->rdir);
931 	kfree(fid);
932 }
933 
934 /* We also need to export tracepoint symbols for tracepoint_enabled() */
935 EXPORT_TRACEPOINT_SYMBOL(9p_fid_ref);
936 
937 void do_trace_9p_fid_get(struct p9_fid *fid)
938 {
939 	trace_9p_fid_ref(fid, P9_FID_REF_GET);
940 }
941 EXPORT_SYMBOL(do_trace_9p_fid_get);
942 
943 void do_trace_9p_fid_put(struct p9_fid *fid)
944 {
945 	trace_9p_fid_ref(fid, P9_FID_REF_PUT);
946 }
947 EXPORT_SYMBOL(do_trace_9p_fid_put);
948 
949 static int p9_client_version(struct p9_client *c)
950 {
951 	int err = 0;
952 	struct p9_req_t *req;
953 	char *version = NULL;
954 	int msize;
955 
956 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
957 		 c->msize, c->proto_version);
958 
959 	switch (c->proto_version) {
960 	case p9_proto_2000L:
961 		req = p9_client_rpc(c, P9_TVERSION, "ds",
962 				    c->msize, "9P2000.L");
963 		break;
964 	case p9_proto_2000u:
965 		req = p9_client_rpc(c, P9_TVERSION, "ds",
966 				    c->msize, "9P2000.u");
967 		break;
968 	case p9_proto_legacy:
969 		req = p9_client_rpc(c, P9_TVERSION, "ds",
970 				    c->msize, "9P2000");
971 		break;
972 	default:
973 		return -EINVAL;
974 	}
975 
976 	if (IS_ERR(req))
977 		return PTR_ERR(req);
978 
979 	err = p9pdu_readf(&req->rc, c->proto_version, "ds", &msize, &version);
980 	if (err) {
981 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
982 		trace_9p_protocol_dump(c, &req->rc);
983 		goto error;
984 	}
985 
986 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
987 	if (!strncmp(version, "9P2000.L", 8)) {
988 		c->proto_version = p9_proto_2000L;
989 	} else if (!strncmp(version, "9P2000.u", 8)) {
990 		c->proto_version = p9_proto_2000u;
991 	} else if (!strncmp(version, "9P2000", 6)) {
992 		c->proto_version = p9_proto_legacy;
993 	} else {
994 		p9_debug(P9_DEBUG_ERROR,
995 			 "server returned an unknown version: %s\n", version);
996 		err = -EREMOTEIO;
997 		goto error;
998 	}
999 
1000 	if (msize < 4096) {
1001 		p9_debug(P9_DEBUG_ERROR,
1002 			 "server returned a msize < 4096: %d\n", msize);
1003 		err = -EREMOTEIO;
1004 		goto error;
1005 	}
1006 	if (msize < c->msize)
1007 		c->msize = msize;
1008 
1009 error:
1010 	kfree(version);
1011 	p9_tag_remove(c, req);
1012 
1013 	return err;
1014 }
1015 
1016 struct p9_client *p9_client_create(const char *dev_name, char *options)
1017 {
1018 	int err;
1019 	struct p9_client *clnt;
1020 	char *client_id;
1021 
1022 	err = 0;
1023 	clnt = kmalloc(sizeof(*clnt), GFP_KERNEL);
1024 	if (!clnt)
1025 		return ERR_PTR(-ENOMEM);
1026 
1027 	clnt->trans_mod = NULL;
1028 	clnt->trans = NULL;
1029 	clnt->fcall_cache = NULL;
1030 
1031 	client_id = utsname()->nodename;
1032 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
1033 
1034 	spin_lock_init(&clnt->lock);
1035 	idr_init(&clnt->fids);
1036 	idr_init(&clnt->reqs);
1037 
1038 	err = parse_opts(options, clnt);
1039 	if (err < 0)
1040 		goto free_client;
1041 
1042 	if (!clnt->trans_mod)
1043 		clnt->trans_mod = v9fs_get_default_trans();
1044 
1045 	if (!clnt->trans_mod) {
1046 		err = -EPROTONOSUPPORT;
1047 		p9_debug(P9_DEBUG_ERROR,
1048 			 "No transport defined or default transport\n");
1049 		goto free_client;
1050 	}
1051 
1052 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
1053 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
1054 
1055 	err = clnt->trans_mod->create(clnt, dev_name, options);
1056 	if (err)
1057 		goto put_trans;
1058 
1059 	if (clnt->msize > clnt->trans_mod->maxsize) {
1060 		clnt->msize = clnt->trans_mod->maxsize;
1061 		pr_info("Limiting 'msize' to %d as this is the maximum "
1062 			"supported by transport %s\n",
1063 			clnt->msize, clnt->trans_mod->name
1064 		);
1065 	}
1066 
1067 	if (clnt->msize < 4096) {
1068 		p9_debug(P9_DEBUG_ERROR,
1069 			 "Please specify a msize of at least 4k\n");
1070 		err = -EINVAL;
1071 		goto close_trans;
1072 	}
1073 
1074 	err = p9_client_version(clnt);
1075 	if (err)
1076 		goto close_trans;
1077 
1078 	/* P9_HDRSZ + 4 is the smallest packet header we can have that is
1079 	 * followed by data accessed from userspace by read
1080 	 */
1081 	clnt->fcall_cache =
1082 		kmem_cache_create_usercopy("9p-fcall-cache", clnt->msize,
1083 					   0, 0, P9_HDRSZ + 4,
1084 					   clnt->msize - (P9_HDRSZ + 4),
1085 					   NULL);
1086 
1087 	return clnt;
1088 
1089 close_trans:
1090 	clnt->trans_mod->close(clnt);
1091 put_trans:
1092 	v9fs_put_trans(clnt->trans_mod);
1093 free_client:
1094 	kfree(clnt);
1095 	return ERR_PTR(err);
1096 }
1097 EXPORT_SYMBOL(p9_client_create);
1098 
1099 void p9_client_destroy(struct p9_client *clnt)
1100 {
1101 	struct p9_fid *fid;
1102 	int id;
1103 
1104 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1105 
1106 	if (clnt->trans_mod)
1107 		clnt->trans_mod->close(clnt);
1108 
1109 	v9fs_put_trans(clnt->trans_mod);
1110 
1111 	idr_for_each_entry(&clnt->fids, fid, id) {
1112 		pr_info("Found fid %d not clunked\n", fid->fid);
1113 		p9_fid_destroy(fid);
1114 	}
1115 
1116 	p9_tag_cleanup(clnt);
1117 
1118 	kmem_cache_destroy(clnt->fcall_cache);
1119 	kfree(clnt);
1120 }
1121 EXPORT_SYMBOL(p9_client_destroy);
1122 
1123 void p9_client_disconnect(struct p9_client *clnt)
1124 {
1125 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1126 	clnt->status = Disconnected;
1127 }
1128 EXPORT_SYMBOL(p9_client_disconnect);
1129 
1130 void p9_client_begin_disconnect(struct p9_client *clnt)
1131 {
1132 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1133 	clnt->status = BeginDisconnect;
1134 }
1135 EXPORT_SYMBOL(p9_client_begin_disconnect);
1136 
1137 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1138 				const char *uname, kuid_t n_uname,
1139 				const char *aname)
1140 {
1141 	int err = 0;
1142 	struct p9_req_t *req;
1143 	struct p9_fid *fid;
1144 	struct p9_qid qid;
1145 
1146 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1147 		 afid ? afid->fid : -1, uname, aname);
1148 	fid = p9_fid_create(clnt);
1149 	if (!fid) {
1150 		err = -ENOMEM;
1151 		goto error;
1152 	}
1153 	fid->uid = n_uname;
1154 
1155 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
1156 			    afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
1157 	if (IS_ERR(req)) {
1158 		err = PTR_ERR(req);
1159 		goto error;
1160 	}
1161 
1162 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", &qid);
1163 	if (err) {
1164 		trace_9p_protocol_dump(clnt, &req->rc);
1165 		p9_tag_remove(clnt, req);
1166 		goto error;
1167 	}
1168 
1169 	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
1170 		 qid.type, qid.path, qid.version);
1171 
1172 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1173 
1174 	p9_tag_remove(clnt, req);
1175 	return fid;
1176 
1177 error:
1178 	if (fid)
1179 		p9_fid_destroy(fid);
1180 	return ERR_PTR(err);
1181 }
1182 EXPORT_SYMBOL(p9_client_attach);
1183 
1184 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
1185 			      const unsigned char * const *wnames, int clone)
1186 {
1187 	int err;
1188 	struct p9_client *clnt;
1189 	struct p9_fid *fid;
1190 	struct p9_qid *wqids;
1191 	struct p9_req_t *req;
1192 	u16 nwqids, count;
1193 
1194 	err = 0;
1195 	wqids = NULL;
1196 	clnt = oldfid->clnt;
1197 	if (clone) {
1198 		fid = p9_fid_create(clnt);
1199 		if (!fid) {
1200 			err = -ENOMEM;
1201 			goto error;
1202 		}
1203 
1204 		fid->uid = oldfid->uid;
1205 	} else {
1206 		fid = oldfid;
1207 	}
1208 
1209 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1210 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1211 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1212 			    nwname, wnames);
1213 	if (IS_ERR(req)) {
1214 		err = PTR_ERR(req);
1215 		goto error;
1216 	}
1217 
1218 	err = p9pdu_readf(&req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1219 	if (err) {
1220 		trace_9p_protocol_dump(clnt, &req->rc);
1221 		p9_tag_remove(clnt, req);
1222 		goto clunk_fid;
1223 	}
1224 	p9_tag_remove(clnt, req);
1225 
1226 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1227 
1228 	if (nwqids != nwname) {
1229 		err = -ENOENT;
1230 		goto clunk_fid;
1231 	}
1232 
1233 	for (count = 0; count < nwqids; count++)
1234 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1235 			 count, wqids[count].type,
1236 			 wqids[count].path,
1237 			 wqids[count].version);
1238 
1239 	if (nwname)
1240 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1241 	else
1242 		memmove(&fid->qid, &oldfid->qid, sizeof(struct p9_qid));
1243 
1244 	kfree(wqids);
1245 	return fid;
1246 
1247 clunk_fid:
1248 	kfree(wqids);
1249 	p9_fid_put(fid);
1250 	fid = NULL;
1251 
1252 error:
1253 	if (fid && fid != oldfid)
1254 		p9_fid_destroy(fid);
1255 
1256 	return ERR_PTR(err);
1257 }
1258 EXPORT_SYMBOL(p9_client_walk);
1259 
1260 int p9_client_open(struct p9_fid *fid, int mode)
1261 {
1262 	int err;
1263 	struct p9_client *clnt;
1264 	struct p9_req_t *req;
1265 	struct p9_qid qid;
1266 	int iounit;
1267 
1268 	clnt = fid->clnt;
1269 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1270 		 p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1271 	err = 0;
1272 
1273 	if (fid->mode != -1)
1274 		return -EINVAL;
1275 
1276 	if (p9_is_proto_dotl(clnt))
1277 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode);
1278 	else
1279 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
1280 	if (IS_ERR(req)) {
1281 		err = PTR_ERR(req);
1282 		goto error;
1283 	}
1284 
1285 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1286 	if (err) {
1287 		trace_9p_protocol_dump(clnt, &req->rc);
1288 		goto free_and_error;
1289 	}
1290 
1291 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1292 		 p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1293 		 qid.path, qid.version, iounit);
1294 
1295 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1296 	fid->mode = mode;
1297 	fid->iounit = iounit;
1298 
1299 free_and_error:
1300 	p9_tag_remove(clnt, req);
1301 error:
1302 	return err;
1303 }
1304 EXPORT_SYMBOL(p9_client_open);
1305 
1306 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags,
1307 			  u32 mode, kgid_t gid, struct p9_qid *qid)
1308 {
1309 	int err = 0;
1310 	struct p9_client *clnt;
1311 	struct p9_req_t *req;
1312 	int iounit;
1313 
1314 	p9_debug(P9_DEBUG_9P,
1315 		 ">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1316 		 ofid->fid, name, flags, mode,
1317 		 from_kgid(&init_user_ns, gid));
1318 	clnt = ofid->clnt;
1319 
1320 	if (ofid->mode != -1)
1321 		return -EINVAL;
1322 
1323 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1324 			    mode, gid);
1325 	if (IS_ERR(req)) {
1326 		err = PTR_ERR(req);
1327 		goto error;
1328 	}
1329 
1330 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", qid, &iounit);
1331 	if (err) {
1332 		trace_9p_protocol_dump(clnt, &req->rc);
1333 		goto free_and_error;
1334 	}
1335 
1336 	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1337 		 qid->type, qid->path, qid->version, iounit);
1338 
1339 	memmove(&ofid->qid, qid, sizeof(struct p9_qid));
1340 	ofid->mode = mode;
1341 	ofid->iounit = iounit;
1342 
1343 free_and_error:
1344 	p9_tag_remove(clnt, req);
1345 error:
1346 	return err;
1347 }
1348 EXPORT_SYMBOL(p9_client_create_dotl);
1349 
1350 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1351 		     char *extension)
1352 {
1353 	int err;
1354 	struct p9_client *clnt;
1355 	struct p9_req_t *req;
1356 	struct p9_qid qid;
1357 	int iounit;
1358 
1359 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1360 		 fid->fid, name, perm, mode);
1361 	err = 0;
1362 	clnt = fid->clnt;
1363 
1364 	if (fid->mode != -1)
1365 		return -EINVAL;
1366 
1367 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1368 			    mode, extension);
1369 	if (IS_ERR(req)) {
1370 		err = PTR_ERR(req);
1371 		goto error;
1372 	}
1373 
1374 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1375 	if (err) {
1376 		trace_9p_protocol_dump(clnt, &req->rc);
1377 		goto free_and_error;
1378 	}
1379 
1380 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1381 		 qid.type, qid.path, qid.version, iounit);
1382 
1383 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1384 	fid->mode = mode;
1385 	fid->iounit = iounit;
1386 
1387 free_and_error:
1388 	p9_tag_remove(clnt, req);
1389 error:
1390 	return err;
1391 }
1392 EXPORT_SYMBOL(p9_client_fcreate);
1393 
1394 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1395 		      const char *symtgt, kgid_t gid, struct p9_qid *qid)
1396 {
1397 	int err = 0;
1398 	struct p9_client *clnt;
1399 	struct p9_req_t *req;
1400 
1401 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1402 		 dfid->fid, name, symtgt);
1403 	clnt = dfid->clnt;
1404 
1405 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1406 			    gid);
1407 	if (IS_ERR(req)) {
1408 		err = PTR_ERR(req);
1409 		goto error;
1410 	}
1411 
1412 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
1413 	if (err) {
1414 		trace_9p_protocol_dump(clnt, &req->rc);
1415 		goto free_and_error;
1416 	}
1417 
1418 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1419 		 qid->type, qid->path, qid->version);
1420 
1421 free_and_error:
1422 	p9_tag_remove(clnt, req);
1423 error:
1424 	return err;
1425 }
1426 EXPORT_SYMBOL(p9_client_symlink);
1427 
1428 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1429 {
1430 	struct p9_client *clnt;
1431 	struct p9_req_t *req;
1432 
1433 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1434 		 dfid->fid, oldfid->fid, newname);
1435 	clnt = dfid->clnt;
1436 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1437 			    newname);
1438 	if (IS_ERR(req))
1439 		return PTR_ERR(req);
1440 
1441 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1442 	p9_tag_remove(clnt, req);
1443 	return 0;
1444 }
1445 EXPORT_SYMBOL(p9_client_link);
1446 
1447 int p9_client_fsync(struct p9_fid *fid, int datasync)
1448 {
1449 	int err;
1450 	struct p9_client *clnt;
1451 	struct p9_req_t *req;
1452 
1453 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1454 		 fid->fid, datasync);
1455 	err = 0;
1456 	clnt = fid->clnt;
1457 
1458 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1459 	if (IS_ERR(req)) {
1460 		err = PTR_ERR(req);
1461 		goto error;
1462 	}
1463 
1464 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1465 
1466 	p9_tag_remove(clnt, req);
1467 
1468 error:
1469 	return err;
1470 }
1471 EXPORT_SYMBOL(p9_client_fsync);
1472 
1473 int p9_client_clunk(struct p9_fid *fid)
1474 {
1475 	int err;
1476 	struct p9_client *clnt;
1477 	struct p9_req_t *req;
1478 	int retries = 0;
1479 
1480 again:
1481 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n",
1482 		 fid->fid, retries);
1483 	err = 0;
1484 	clnt = fid->clnt;
1485 
1486 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1487 	if (IS_ERR(req)) {
1488 		err = PTR_ERR(req);
1489 		goto error;
1490 	}
1491 
1492 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1493 
1494 	p9_tag_remove(clnt, req);
1495 error:
1496 	/* Fid is not valid even after a failed clunk
1497 	 * If interrupted, retry once then give up and
1498 	 * leak fid until umount.
1499 	 */
1500 	if (err == -ERESTARTSYS) {
1501 		if (retries++ == 0)
1502 			goto again;
1503 	} else {
1504 		p9_fid_destroy(fid);
1505 	}
1506 	return err;
1507 }
1508 EXPORT_SYMBOL(p9_client_clunk);
1509 
1510 int p9_client_remove(struct p9_fid *fid)
1511 {
1512 	int err;
1513 	struct p9_client *clnt;
1514 	struct p9_req_t *req;
1515 
1516 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1517 	err = 0;
1518 	clnt = fid->clnt;
1519 
1520 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1521 	if (IS_ERR(req)) {
1522 		err = PTR_ERR(req);
1523 		goto error;
1524 	}
1525 
1526 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1527 
1528 	p9_tag_remove(clnt, req);
1529 error:
1530 	if (err == -ERESTARTSYS)
1531 		p9_fid_put(fid);
1532 	else
1533 		p9_fid_destroy(fid);
1534 	return err;
1535 }
1536 EXPORT_SYMBOL(p9_client_remove);
1537 
1538 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1539 {
1540 	int err = 0;
1541 	struct p9_req_t *req;
1542 	struct p9_client *clnt;
1543 
1544 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1545 		 dfid->fid, name, flags);
1546 
1547 	clnt = dfid->clnt;
1548 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1549 	if (IS_ERR(req)) {
1550 		err = PTR_ERR(req);
1551 		goto error;
1552 	}
1553 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1554 
1555 	p9_tag_remove(clnt, req);
1556 error:
1557 	return err;
1558 }
1559 EXPORT_SYMBOL(p9_client_unlinkat);
1560 
1561 int
1562 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1563 {
1564 	int total = 0;
1565 	*err = 0;
1566 
1567 	while (iov_iter_count(to)) {
1568 		int count;
1569 
1570 		count = p9_client_read_once(fid, offset, to, err);
1571 		if (!count || *err)
1572 			break;
1573 		offset += count;
1574 		total += count;
1575 	}
1576 	return total;
1577 }
1578 EXPORT_SYMBOL(p9_client_read);
1579 
1580 int
1581 p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
1582 		    int *err)
1583 {
1584 	struct p9_client *clnt = fid->clnt;
1585 	struct p9_req_t *req;
1586 	int count = iov_iter_count(to);
1587 	int rsize, non_zc = 0;
1588 	char *dataptr;
1589 
1590 	*err = 0;
1591 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %zu\n",
1592 		 fid->fid, offset, iov_iter_count(to));
1593 
1594 	rsize = fid->iounit;
1595 	if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1596 		rsize = clnt->msize - P9_IOHDRSZ;
1597 
1598 	if (count < rsize)
1599 		rsize = count;
1600 
1601 	/* Don't bother zerocopy for small IO (< 1024) */
1602 	if (clnt->trans_mod->zc_request && rsize > 1024) {
1603 		/* response header len is 11
1604 		 * PDU Header(7) + IO Size (4)
1605 		 */
1606 		req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1607 				       0, 11, "dqd", fid->fid,
1608 				       offset, rsize);
1609 	} else {
1610 		non_zc = 1;
1611 		req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1612 				    rsize);
1613 	}
1614 	if (IS_ERR(req)) {
1615 		*err = PTR_ERR(req);
1616 		return 0;
1617 	}
1618 
1619 	*err = p9pdu_readf(&req->rc, clnt->proto_version,
1620 			   "D", &count, &dataptr);
1621 	if (*err) {
1622 		trace_9p_protocol_dump(clnt, &req->rc);
1623 		p9_tag_remove(clnt, req);
1624 		return 0;
1625 	}
1626 	if (rsize < count) {
1627 		pr_err("bogus RREAD count (%d > %d)\n", count, rsize);
1628 		count = rsize;
1629 	}
1630 
1631 	p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1632 
1633 	if (non_zc) {
1634 		int n = copy_to_iter(dataptr, count, to);
1635 
1636 		if (n != count) {
1637 			*err = -EFAULT;
1638 			p9_tag_remove(clnt, req);
1639 			return n;
1640 		}
1641 	} else {
1642 		iov_iter_advance(to, count);
1643 	}
1644 	p9_tag_remove(clnt, req);
1645 	return count;
1646 }
1647 EXPORT_SYMBOL(p9_client_read_once);
1648 
1649 int
1650 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1651 {
1652 	struct p9_client *clnt = fid->clnt;
1653 	struct p9_req_t *req;
1654 	int total = 0;
1655 	*err = 0;
1656 
1657 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n",
1658 		 fid->fid, offset, iov_iter_count(from));
1659 
1660 	while (iov_iter_count(from)) {
1661 		int count = iov_iter_count(from);
1662 		int rsize = fid->iounit;
1663 
1664 		if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1665 			rsize = clnt->msize - P9_IOHDRSZ;
1666 
1667 		if (count < rsize)
1668 			rsize = count;
1669 
1670 		/* Don't bother zerocopy for small IO (< 1024) */
1671 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1672 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1673 					       rsize, P9_ZC_HDR_SZ, "dqd",
1674 					       fid->fid, offset, rsize);
1675 		} else {
1676 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1677 					    offset, rsize, from);
1678 		}
1679 		if (IS_ERR(req)) {
1680 			*err = PTR_ERR(req);
1681 			break;
1682 		}
1683 
1684 		*err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &count);
1685 		if (*err) {
1686 			trace_9p_protocol_dump(clnt, &req->rc);
1687 			p9_tag_remove(clnt, req);
1688 			break;
1689 		}
1690 		if (rsize < count) {
1691 			pr_err("bogus RWRITE count (%d > %d)\n", count, rsize);
1692 			count = rsize;
1693 		}
1694 
1695 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1696 
1697 		p9_tag_remove(clnt, req);
1698 		iov_iter_advance(from, count);
1699 		total += count;
1700 		offset += count;
1701 	}
1702 	return total;
1703 }
1704 EXPORT_SYMBOL(p9_client_write);
1705 
1706 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1707 {
1708 	int err;
1709 	struct p9_client *clnt;
1710 	struct p9_wstat *ret;
1711 	struct p9_req_t *req;
1712 	u16 ignored;
1713 
1714 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1715 
1716 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1717 	if (!ret)
1718 		return ERR_PTR(-ENOMEM);
1719 
1720 	err = 0;
1721 	clnt = fid->clnt;
1722 
1723 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1724 	if (IS_ERR(req)) {
1725 		err = PTR_ERR(req);
1726 		goto error;
1727 	}
1728 
1729 	err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
1730 	if (err) {
1731 		trace_9p_protocol_dump(clnt, &req->rc);
1732 		p9_tag_remove(clnt, req);
1733 		goto error;
1734 	}
1735 
1736 	p9_debug(P9_DEBUG_9P,
1737 		 "<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1738 		 "<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1739 		 "<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1740 		 "<<<    uid=%d gid=%d n_muid=%d\n",
1741 		 ret->size, ret->type, ret->dev, ret->qid.type, ret->qid.path,
1742 		 ret->qid.version, ret->mode,
1743 		 ret->atime, ret->mtime, ret->length,
1744 		 ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1745 		 from_kuid(&init_user_ns, ret->n_uid),
1746 		 from_kgid(&init_user_ns, ret->n_gid),
1747 		 from_kuid(&init_user_ns, ret->n_muid));
1748 
1749 	p9_tag_remove(clnt, req);
1750 	return ret;
1751 
1752 error:
1753 	kfree(ret);
1754 	return ERR_PTR(err);
1755 }
1756 EXPORT_SYMBOL(p9_client_stat);
1757 
1758 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1759 					    u64 request_mask)
1760 {
1761 	int err;
1762 	struct p9_client *clnt;
1763 	struct p9_stat_dotl *ret;
1764 	struct p9_req_t *req;
1765 
1766 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1767 		 fid->fid, request_mask);
1768 
1769 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1770 	if (!ret)
1771 		return ERR_PTR(-ENOMEM);
1772 
1773 	err = 0;
1774 	clnt = fid->clnt;
1775 
1776 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1777 	if (IS_ERR(req)) {
1778 		err = PTR_ERR(req);
1779 		goto error;
1780 	}
1781 
1782 	err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
1783 	if (err) {
1784 		trace_9p_protocol_dump(clnt, &req->rc);
1785 		p9_tag_remove(clnt, req);
1786 		goto error;
1787 	}
1788 
1789 	p9_debug(P9_DEBUG_9P, "<<< RGETATTR st_result_mask=%lld\n"
1790 		 "<<< qid=%x.%llx.%x\n"
1791 		 "<<< st_mode=%8.8x st_nlink=%llu\n"
1792 		 "<<< st_uid=%d st_gid=%d\n"
1793 		 "<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1794 		 "<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1795 		 "<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1796 		 "<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1797 		 "<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1798 		 "<<< st_gen=%lld st_data_version=%lld\n",
1799 		 ret->st_result_mask,
1800 		 ret->qid.type, ret->qid.path, ret->qid.version,
1801 		 ret->st_mode, ret->st_nlink,
1802 		 from_kuid(&init_user_ns, ret->st_uid),
1803 		 from_kgid(&init_user_ns, ret->st_gid),
1804 		 ret->st_rdev, ret->st_size, ret->st_blksize, ret->st_blocks,
1805 		 ret->st_atime_sec, ret->st_atime_nsec,
1806 		 ret->st_mtime_sec, ret->st_mtime_nsec,
1807 		 ret->st_ctime_sec, ret->st_ctime_nsec,
1808 		 ret->st_btime_sec, ret->st_btime_nsec,
1809 		 ret->st_gen, ret->st_data_version);
1810 
1811 	p9_tag_remove(clnt, req);
1812 	return ret;
1813 
1814 error:
1815 	kfree(ret);
1816 	return ERR_PTR(err);
1817 }
1818 EXPORT_SYMBOL(p9_client_getattr_dotl);
1819 
1820 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1821 {
1822 	int ret;
1823 
1824 	/* NOTE: size shouldn't include its own length */
1825 	/* size[2] type[2] dev[4] qid[13] */
1826 	/* mode[4] atime[4] mtime[4] length[8]*/
1827 	/* name[s] uid[s] gid[s] muid[s] */
1828 	ret = 2 + 4 + 13 + 4 + 4 + 4 + 8 + 2 + 2 + 2 + 2;
1829 
1830 	if (wst->name)
1831 		ret += strlen(wst->name);
1832 	if (wst->uid)
1833 		ret += strlen(wst->uid);
1834 	if (wst->gid)
1835 		ret += strlen(wst->gid);
1836 	if (wst->muid)
1837 		ret += strlen(wst->muid);
1838 
1839 	if (proto_version == p9_proto_2000u ||
1840 	    proto_version == p9_proto_2000L) {
1841 		/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1842 		ret += 2 + 4 + 4 + 4;
1843 		if (wst->extension)
1844 			ret += strlen(wst->extension);
1845 	}
1846 
1847 	return ret;
1848 }
1849 
1850 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1851 {
1852 	int err;
1853 	struct p9_req_t *req;
1854 	struct p9_client *clnt;
1855 
1856 	err = 0;
1857 	clnt = fid->clnt;
1858 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1859 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n",
1860 		 fid->fid);
1861 	p9_debug(P9_DEBUG_9P,
1862 		 "     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1863 		 "     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1864 		 "     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1865 		 "     uid=%d gid=%d n_muid=%d\n",
1866 		 wst->size, wst->type, wst->dev, wst->qid.type,
1867 		 wst->qid.path, wst->qid.version,
1868 		 wst->mode, wst->atime, wst->mtime, wst->length,
1869 		 wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1870 		 from_kuid(&init_user_ns, wst->n_uid),
1871 		 from_kgid(&init_user_ns, wst->n_gid),
1872 		 from_kuid(&init_user_ns, wst->n_muid));
1873 
1874 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS",
1875 			    fid->fid, wst->size + 2, wst);
1876 	if (IS_ERR(req)) {
1877 		err = PTR_ERR(req);
1878 		goto error;
1879 	}
1880 
1881 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1882 
1883 	p9_tag_remove(clnt, req);
1884 error:
1885 	return err;
1886 }
1887 EXPORT_SYMBOL(p9_client_wstat);
1888 
1889 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1890 {
1891 	int err;
1892 	struct p9_req_t *req;
1893 	struct p9_client *clnt;
1894 
1895 	err = 0;
1896 	clnt = fid->clnt;
1897 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1898 	p9_debug(P9_DEBUG_9P, "    valid=%x mode=%x uid=%d gid=%d size=%lld\n",
1899 		 p9attr->valid, p9attr->mode,
1900 		 from_kuid(&init_user_ns, p9attr->uid),
1901 		 from_kgid(&init_user_ns, p9attr->gid),
1902 		 p9attr->size);
1903 	p9_debug(P9_DEBUG_9P, "    atime_sec=%lld atime_nsec=%lld\n",
1904 		 p9attr->atime_sec, p9attr->atime_nsec);
1905 	p9_debug(P9_DEBUG_9P, "    mtime_sec=%lld mtime_nsec=%lld\n",
1906 		 p9attr->mtime_sec, p9attr->mtime_nsec);
1907 
1908 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1909 
1910 	if (IS_ERR(req)) {
1911 		err = PTR_ERR(req);
1912 		goto error;
1913 	}
1914 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1915 	p9_tag_remove(clnt, req);
1916 error:
1917 	return err;
1918 }
1919 EXPORT_SYMBOL(p9_client_setattr);
1920 
1921 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1922 {
1923 	int err;
1924 	struct p9_req_t *req;
1925 	struct p9_client *clnt;
1926 
1927 	err = 0;
1928 	clnt = fid->clnt;
1929 
1930 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1931 
1932 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1933 	if (IS_ERR(req)) {
1934 		err = PTR_ERR(req);
1935 		goto error;
1936 	}
1937 
1938 	err = p9pdu_readf(&req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1939 			  &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1940 			  &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1941 	if (err) {
1942 		trace_9p_protocol_dump(clnt, &req->rc);
1943 		p9_tag_remove(clnt, req);
1944 		goto error;
1945 	}
1946 
1947 	p9_debug(P9_DEBUG_9P,
1948 		 "<<< RSTATFS fid %d type 0x%x bsize %u blocks %llu bfree %llu bavail %llu files %llu ffree %llu fsid %llu namelen %u\n",
1949 		 fid->fid, sb->type, sb->bsize, sb->blocks, sb->bfree,
1950 		 sb->bavail, sb->files, sb->ffree, sb->fsid, sb->namelen);
1951 
1952 	p9_tag_remove(clnt, req);
1953 error:
1954 	return err;
1955 }
1956 EXPORT_SYMBOL(p9_client_statfs);
1957 
1958 int p9_client_rename(struct p9_fid *fid,
1959 		     struct p9_fid *newdirfid, const char *name)
1960 {
1961 	int err;
1962 	struct p9_req_t *req;
1963 	struct p9_client *clnt;
1964 
1965 	err = 0;
1966 	clnt = fid->clnt;
1967 
1968 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1969 		 fid->fid, newdirfid->fid, name);
1970 
1971 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1972 			    newdirfid->fid, name);
1973 	if (IS_ERR(req)) {
1974 		err = PTR_ERR(req);
1975 		goto error;
1976 	}
1977 
1978 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1979 
1980 	p9_tag_remove(clnt, req);
1981 error:
1982 	return err;
1983 }
1984 EXPORT_SYMBOL(p9_client_rename);
1985 
1986 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
1987 		       struct p9_fid *newdirfid, const char *new_name)
1988 {
1989 	int err;
1990 	struct p9_req_t *req;
1991 	struct p9_client *clnt;
1992 
1993 	err = 0;
1994 	clnt = olddirfid->clnt;
1995 
1996 	p9_debug(P9_DEBUG_9P,
1997 		 ">>> TRENAMEAT olddirfid %d old name %s newdirfid %d new name %s\n",
1998 		 olddirfid->fid, old_name, newdirfid->fid, new_name);
1999 
2000 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
2001 			    old_name, newdirfid->fid, new_name);
2002 	if (IS_ERR(req)) {
2003 		err = PTR_ERR(req);
2004 		goto error;
2005 	}
2006 
2007 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
2008 		 newdirfid->fid, new_name);
2009 
2010 	p9_tag_remove(clnt, req);
2011 error:
2012 	return err;
2013 }
2014 EXPORT_SYMBOL(p9_client_renameat);
2015 
2016 /* An xattrwalk without @attr_name gives the fid for the lisxattr namespace
2017  */
2018 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
2019 				   const char *attr_name, u64 *attr_size)
2020 {
2021 	int err;
2022 	struct p9_req_t *req;
2023 	struct p9_client *clnt;
2024 	struct p9_fid *attr_fid;
2025 
2026 	err = 0;
2027 	clnt = file_fid->clnt;
2028 	attr_fid = p9_fid_create(clnt);
2029 	if (!attr_fid) {
2030 		err = -ENOMEM;
2031 		goto error;
2032 	}
2033 	p9_debug(P9_DEBUG_9P,
2034 		 ">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
2035 		 file_fid->fid, attr_fid->fid, attr_name);
2036 
2037 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
2038 			    file_fid->fid, attr_fid->fid, attr_name);
2039 	if (IS_ERR(req)) {
2040 		err = PTR_ERR(req);
2041 		goto error;
2042 	}
2043 	err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
2044 	if (err) {
2045 		trace_9p_protocol_dump(clnt, &req->rc);
2046 		p9_tag_remove(clnt, req);
2047 		goto clunk_fid;
2048 	}
2049 	p9_tag_remove(clnt, req);
2050 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
2051 		 attr_fid->fid, *attr_size);
2052 	return attr_fid;
2053 clunk_fid:
2054 	p9_fid_put(attr_fid);
2055 	attr_fid = NULL;
2056 error:
2057 	if (attr_fid && attr_fid != file_fid)
2058 		p9_fid_destroy(attr_fid);
2059 
2060 	return ERR_PTR(err);
2061 }
2062 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
2063 
2064 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
2065 			  u64 attr_size, int flags)
2066 {
2067 	int err;
2068 	struct p9_req_t *req;
2069 	struct p9_client *clnt;
2070 
2071 	p9_debug(P9_DEBUG_9P,
2072 		 ">>> TXATTRCREATE fid %d name  %s size %llu flag %d\n",
2073 		 fid->fid, name, attr_size, flags);
2074 	err = 0;
2075 	clnt = fid->clnt;
2076 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
2077 			    fid->fid, name, attr_size, flags);
2078 	if (IS_ERR(req)) {
2079 		err = PTR_ERR(req);
2080 		goto error;
2081 	}
2082 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
2083 	p9_tag_remove(clnt, req);
2084 error:
2085 	return err;
2086 }
2087 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
2088 
2089 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
2090 {
2091 	int err, rsize, non_zc = 0;
2092 	struct p9_client *clnt;
2093 	struct p9_req_t *req;
2094 	char *dataptr;
2095 	struct kvec kv = {.iov_base = data, .iov_len = count};
2096 	struct iov_iter to;
2097 
2098 	iov_iter_kvec(&to, READ, &kv, 1, count);
2099 
2100 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
2101 		 fid->fid, offset, count);
2102 
2103 	err = 0;
2104 	clnt = fid->clnt;
2105 
2106 	rsize = fid->iounit;
2107 	if (!rsize || rsize > clnt->msize - P9_READDIRHDRSZ)
2108 		rsize = clnt->msize - P9_READDIRHDRSZ;
2109 
2110 	if (count < rsize)
2111 		rsize = count;
2112 
2113 	/* Don't bother zerocopy for small IO (< 1024) */
2114 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2115 		/* response header len is 11
2116 		 * PDU Header(7) + IO Size (4)
2117 		 */
2118 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2119 				       11, "dqd", fid->fid, offset, rsize);
2120 	} else {
2121 		non_zc = 1;
2122 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2123 				    offset, rsize);
2124 	}
2125 	if (IS_ERR(req)) {
2126 		err = PTR_ERR(req);
2127 		goto error;
2128 	}
2129 
2130 	err = p9pdu_readf(&req->rc, clnt->proto_version, "D", &count, &dataptr);
2131 	if (err) {
2132 		trace_9p_protocol_dump(clnt, &req->rc);
2133 		goto free_and_error;
2134 	}
2135 	if (rsize < count) {
2136 		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
2137 		count = rsize;
2138 	}
2139 
2140 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
2141 
2142 	if (non_zc)
2143 		memmove(data, dataptr, count);
2144 
2145 	p9_tag_remove(clnt, req);
2146 	return count;
2147 
2148 free_and_error:
2149 	p9_tag_remove(clnt, req);
2150 error:
2151 	return err;
2152 }
2153 EXPORT_SYMBOL(p9_client_readdir);
2154 
2155 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2156 			 dev_t rdev, kgid_t gid, struct p9_qid *qid)
2157 {
2158 	int err;
2159 	struct p9_client *clnt;
2160 	struct p9_req_t *req;
2161 
2162 	err = 0;
2163 	clnt = fid->clnt;
2164 	p9_debug(P9_DEBUG_9P,
2165 		 ">>> TMKNOD fid %d name %s mode %d major %d minor %d\n",
2166 		 fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2167 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2168 			    MAJOR(rdev), MINOR(rdev), gid);
2169 	if (IS_ERR(req))
2170 		return PTR_ERR(req);
2171 
2172 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2173 	if (err) {
2174 		trace_9p_protocol_dump(clnt, &req->rc);
2175 		goto error;
2176 	}
2177 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n",
2178 		 qid->type, qid->path, qid->version);
2179 
2180 error:
2181 	p9_tag_remove(clnt, req);
2182 	return err;
2183 }
2184 EXPORT_SYMBOL(p9_client_mknod_dotl);
2185 
2186 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2187 			 kgid_t gid, struct p9_qid *qid)
2188 {
2189 	int err;
2190 	struct p9_client *clnt;
2191 	struct p9_req_t *req;
2192 
2193 	err = 0;
2194 	clnt = fid->clnt;
2195 	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
2196 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
2197 	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg",
2198 			    fid->fid, name, mode, gid);
2199 	if (IS_ERR(req))
2200 		return PTR_ERR(req);
2201 
2202 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2203 	if (err) {
2204 		trace_9p_protocol_dump(clnt, &req->rc);
2205 		goto error;
2206 	}
2207 	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
2208 		 qid->path, qid->version);
2209 
2210 error:
2211 	p9_tag_remove(clnt, req);
2212 	return err;
2213 }
2214 EXPORT_SYMBOL(p9_client_mkdir_dotl);
2215 
2216 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
2217 {
2218 	int err;
2219 	struct p9_client *clnt;
2220 	struct p9_req_t *req;
2221 
2222 	err = 0;
2223 	clnt = fid->clnt;
2224 	p9_debug(P9_DEBUG_9P,
2225 		 ">>> TLOCK fid %d type %i flags %d start %lld length %lld proc_id %d client_id %s\n",
2226 		 fid->fid, flock->type, flock->flags, flock->start,
2227 		 flock->length, flock->proc_id, flock->client_id);
2228 
2229 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2230 			    flock->flags, flock->start, flock->length,
2231 			    flock->proc_id, flock->client_id);
2232 
2233 	if (IS_ERR(req))
2234 		return PTR_ERR(req);
2235 
2236 	err = p9pdu_readf(&req->rc, clnt->proto_version, "b", status);
2237 	if (err) {
2238 		trace_9p_protocol_dump(clnt, &req->rc);
2239 		goto error;
2240 	}
2241 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2242 error:
2243 	p9_tag_remove(clnt, req);
2244 	return err;
2245 }
2246 EXPORT_SYMBOL(p9_client_lock_dotl);
2247 
2248 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2249 {
2250 	int err;
2251 	struct p9_client *clnt;
2252 	struct p9_req_t *req;
2253 
2254 	err = 0;
2255 	clnt = fid->clnt;
2256 	p9_debug(P9_DEBUG_9P,
2257 		 ">>> TGETLOCK fid %d, type %i start %lld length %lld proc_id %d client_id %s\n",
2258 		 fid->fid, glock->type, glock->start, glock->length,
2259 		 glock->proc_id, glock->client_id);
2260 
2261 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,
2262 			    glock->type, glock->start, glock->length,
2263 			    glock->proc_id, glock->client_id);
2264 
2265 	if (IS_ERR(req))
2266 		return PTR_ERR(req);
2267 
2268 	err = p9pdu_readf(&req->rc, clnt->proto_version, "bqqds", &glock->type,
2269 			  &glock->start, &glock->length, &glock->proc_id,
2270 			  &glock->client_id);
2271 	if (err) {
2272 		trace_9p_protocol_dump(clnt, &req->rc);
2273 		goto error;
2274 	}
2275 	p9_debug(P9_DEBUG_9P,
2276 		 "<<< RGETLOCK type %i start %lld length %lld proc_id %d client_id %s\n",
2277 		 glock->type, glock->start, glock->length,
2278 		 glock->proc_id, glock->client_id);
2279 error:
2280 	p9_tag_remove(clnt, req);
2281 	return err;
2282 }
2283 EXPORT_SYMBOL(p9_client_getlock_dotl);
2284 
2285 int p9_client_readlink(struct p9_fid *fid, char **target)
2286 {
2287 	int err;
2288 	struct p9_client *clnt;
2289 	struct p9_req_t *req;
2290 
2291 	err = 0;
2292 	clnt = fid->clnt;
2293 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2294 
2295 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2296 	if (IS_ERR(req))
2297 		return PTR_ERR(req);
2298 
2299 	err = p9pdu_readf(&req->rc, clnt->proto_version, "s", target);
2300 	if (err) {
2301 		trace_9p_protocol_dump(clnt, &req->rc);
2302 		goto error;
2303 	}
2304 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2305 error:
2306 	p9_tag_remove(clnt, req);
2307 	return err;
2308 }
2309 EXPORT_SYMBOL(p9_client_readlink);
2310 
2311 int __init p9_client_init(void)
2312 {
2313 	p9_req_cache = KMEM_CACHE(p9_req_t, SLAB_TYPESAFE_BY_RCU);
2314 	return p9_req_cache ? 0 : -ENOMEM;
2315 }
2316 
2317 void __exit p9_client_exit(void)
2318 {
2319 	kmem_cache_destroy(p9_req_cache);
2320 }
2321