xref: /openbmc/linux/net/9p/client.c (revision 728356de)
1 /*
2  * net/9p/clnt.c
3  *
4  * 9P Client
5  *
6  *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
7  *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
8  *
9  *  This program is free software; you can redistribute it and/or modify
10  *  it under the terms of the GNU General Public License version 2
11  *  as published by the Free Software Foundation.
12  *
13  *  This program is distributed in the hope that it will be useful,
14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  *  GNU General Public License for more details.
17  *
18  *  You should have received a copy of the GNU General Public License
19  *  along with this program; if not, write to:
20  *  Free Software Foundation
21  *  51 Franklin Street, Fifth Floor
22  *  Boston, MA  02111-1301  USA
23  *
24  */
25 
26 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27 
28 #include <linux/module.h>
29 #include <linux/errno.h>
30 #include <linux/fs.h>
31 #include <linux/poll.h>
32 #include <linux/idr.h>
33 #include <linux/mutex.h>
34 #include <linux/slab.h>
35 #include <linux/sched/signal.h>
36 #include <linux/uaccess.h>
37 #include <linux/uio.h>
38 #include <net/9p/9p.h>
39 #include <linux/parser.h>
40 #include <linux/seq_file.h>
41 #include <net/9p/client.h>
42 #include <net/9p/transport.h>
43 #include "protocol.h"
44 
45 #define CREATE_TRACE_POINTS
46 #include <trace/events/9p.h>
47 
48 /*
49   * Client Option Parsing (code inspired by NFS code)
50   *  - a little lazy - parse all client options
51   */
52 
53 enum {
54 	Opt_msize,
55 	Opt_trans,
56 	Opt_legacy,
57 	Opt_version,
58 	Opt_err,
59 };
60 
61 static const match_table_t tokens = {
62 	{Opt_msize, "msize=%u"},
63 	{Opt_legacy, "noextend"},
64 	{Opt_trans, "trans=%s"},
65 	{Opt_version, "version=%s"},
66 	{Opt_err, NULL},
67 };
68 
69 inline int p9_is_proto_dotl(struct p9_client *clnt)
70 {
71 	return clnt->proto_version == p9_proto_2000L;
72 }
73 EXPORT_SYMBOL(p9_is_proto_dotl);
74 
75 inline int p9_is_proto_dotu(struct p9_client *clnt)
76 {
77 	return clnt->proto_version == p9_proto_2000u;
78 }
79 EXPORT_SYMBOL(p9_is_proto_dotu);
80 
81 int p9_show_client_options(struct seq_file *m, struct p9_client *clnt)
82 {
83 	if (clnt->msize != 8192)
84 		seq_printf(m, ",msize=%u", clnt->msize);
85 	seq_printf(m, ",trans=%s", clnt->trans_mod->name);
86 
87 	switch (clnt->proto_version) {
88 	case p9_proto_legacy:
89 		seq_puts(m, ",noextend");
90 		break;
91 	case p9_proto_2000u:
92 		seq_puts(m, ",version=9p2000.u");
93 		break;
94 	case p9_proto_2000L:
95 		/* Default */
96 		break;
97 	}
98 
99 	if (clnt->trans_mod->show_options)
100 		return clnt->trans_mod->show_options(m, clnt);
101 	return 0;
102 }
103 EXPORT_SYMBOL(p9_show_client_options);
104 
105 /*
106  * Some error codes are taken directly from the server replies,
107  * make sure they are valid.
108  */
109 static int safe_errno(int err)
110 {
111 	if ((err > 0) || (err < -MAX_ERRNO)) {
112 		p9_debug(P9_DEBUG_ERROR, "Invalid error code %d\n", err);
113 		return -EPROTO;
114 	}
115 	return err;
116 }
117 
118 
119 /* Interpret mount option for protocol version */
120 static int get_protocol_version(char *s)
121 {
122 	int version = -EINVAL;
123 
124 	if (!strcmp(s, "9p2000")) {
125 		version = p9_proto_legacy;
126 		p9_debug(P9_DEBUG_9P, "Protocol version: Legacy\n");
127 	} else if (!strcmp(s, "9p2000.u")) {
128 		version = p9_proto_2000u;
129 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.u\n");
130 	} else if (!strcmp(s, "9p2000.L")) {
131 		version = p9_proto_2000L;
132 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.L\n");
133 	} else
134 		pr_info("Unknown protocol version %s\n", s);
135 
136 	return version;
137 }
138 
139 /**
140  * parse_options - parse mount options into client structure
141  * @opts: options string passed from mount
142  * @clnt: existing v9fs client information
143  *
144  * Return 0 upon success, -ERRNO upon failure
145  */
146 
147 static int parse_opts(char *opts, struct p9_client *clnt)
148 {
149 	char *options, *tmp_options;
150 	char *p;
151 	substring_t args[MAX_OPT_ARGS];
152 	int option;
153 	char *s;
154 	int ret = 0;
155 
156 	clnt->proto_version = p9_proto_2000L;
157 	clnt->msize = 8192;
158 
159 	if (!opts)
160 		return 0;
161 
162 	tmp_options = kstrdup(opts, GFP_KERNEL);
163 	if (!tmp_options) {
164 		p9_debug(P9_DEBUG_ERROR,
165 			 "failed to allocate copy of option string\n");
166 		return -ENOMEM;
167 	}
168 	options = tmp_options;
169 
170 	while ((p = strsep(&options, ",")) != NULL) {
171 		int token, r;
172 		if (!*p)
173 			continue;
174 		token = match_token(p, tokens, args);
175 		switch (token) {
176 		case Opt_msize:
177 			r = match_int(&args[0], &option);
178 			if (r < 0) {
179 				p9_debug(P9_DEBUG_ERROR,
180 					 "integer field, but no integer?\n");
181 				ret = r;
182 				continue;
183 			}
184 			clnt->msize = option;
185 			break;
186 		case Opt_trans:
187 			s = match_strdup(&args[0]);
188 			if (!s) {
189 				ret = -ENOMEM;
190 				p9_debug(P9_DEBUG_ERROR,
191 					 "problem allocating copy of trans arg\n");
192 				goto free_and_return;
193 			}
194 
195 			v9fs_put_trans(clnt->trans_mod);
196 			clnt->trans_mod = v9fs_get_trans_by_name(s);
197 			if (clnt->trans_mod == NULL) {
198 				pr_info("Could not find request transport: %s\n",
199 					s);
200 				ret = -EINVAL;
201 			}
202 			kfree(s);
203 			break;
204 		case Opt_legacy:
205 			clnt->proto_version = p9_proto_legacy;
206 			break;
207 		case Opt_version:
208 			s = match_strdup(&args[0]);
209 			if (!s) {
210 				ret = -ENOMEM;
211 				p9_debug(P9_DEBUG_ERROR,
212 					 "problem allocating copy of version arg\n");
213 				goto free_and_return;
214 			}
215 			r = get_protocol_version(s);
216 			if (r < 0)
217 				ret = r;
218 			else
219 				clnt->proto_version = r;
220 			kfree(s);
221 			break;
222 		default:
223 			continue;
224 		}
225 	}
226 
227 free_and_return:
228 	if (ret)
229 		v9fs_put_trans(clnt->trans_mod);
230 	kfree(tmp_options);
231 	return ret;
232 }
233 
234 static int p9_fcall_init(struct p9_client *c, struct p9_fcall *fc,
235 			 int alloc_msize)
236 {
237 	if (likely(c->fcall_cache) && alloc_msize == c->msize) {
238 		fc->sdata = kmem_cache_alloc(c->fcall_cache, GFP_NOFS);
239 		fc->cache = c->fcall_cache;
240 	} else {
241 		fc->sdata = kmalloc(alloc_msize, GFP_NOFS);
242 		fc->cache = NULL;
243 	}
244 	if (!fc->sdata)
245 		return -ENOMEM;
246 	fc->capacity = alloc_msize;
247 	return 0;
248 }
249 
250 void p9_fcall_fini(struct p9_fcall *fc)
251 {
252 	/* sdata can be NULL for interrupted requests in trans_rdma,
253 	 * and kmem_cache_free does not do NULL-check for us
254 	 */
255 	if (unlikely(!fc->sdata))
256 		return;
257 
258 	if (fc->cache)
259 		kmem_cache_free(fc->cache, fc->sdata);
260 	else
261 		kfree(fc->sdata);
262 }
263 EXPORT_SYMBOL(p9_fcall_fini);
264 
265 static struct kmem_cache *p9_req_cache;
266 
267 /**
268  * p9_req_alloc - Allocate a new request.
269  * @c: Client session.
270  * @type: Transaction type.
271  * @max_size: Maximum packet size for this request.
272  *
273  * Context: Process context.
274  * Return: Pointer to new request.
275  */
276 static struct p9_req_t *
277 p9_tag_alloc(struct p9_client *c, int8_t type, unsigned int max_size)
278 {
279 	struct p9_req_t *req = kmem_cache_alloc(p9_req_cache, GFP_NOFS);
280 	int alloc_msize = min(c->msize, max_size);
281 	int tag;
282 
283 	if (!req)
284 		return NULL;
285 
286 	if (p9_fcall_init(c, &req->tc, alloc_msize))
287 		goto free_req;
288 	if (p9_fcall_init(c, &req->rc, alloc_msize))
289 		goto free;
290 
291 	p9pdu_reset(&req->tc);
292 	p9pdu_reset(&req->rc);
293 	req->status = REQ_STATUS_ALLOC;
294 	init_waitqueue_head(&req->wq);
295 	INIT_LIST_HEAD(&req->req_list);
296 
297 	idr_preload(GFP_NOFS);
298 	spin_lock_irq(&c->lock);
299 	if (type == P9_TVERSION)
300 		tag = idr_alloc(&c->reqs, req, P9_NOTAG, P9_NOTAG + 1,
301 				GFP_NOWAIT);
302 	else
303 		tag = idr_alloc(&c->reqs, req, 0, P9_NOTAG, GFP_NOWAIT);
304 	req->tc.tag = tag;
305 	spin_unlock_irq(&c->lock);
306 	idr_preload_end();
307 	if (tag < 0)
308 		goto free;
309 
310 	/* Init ref to two because in the general case there is one ref
311 	 * that is put asynchronously by a writer thread, one ref
312 	 * temporarily given by p9_tag_lookup and put by p9_client_cb
313 	 * in the recv thread, and one ref put by p9_tag_remove in the
314 	 * main thread. The only exception is virtio that does not use
315 	 * p9_tag_lookup but does not have a writer thread either
316 	 * (the write happens synchronously in the request/zc_request
317 	 * callback), so p9_client_cb eats the second ref there
318 	 * as the pointer is duplicated directly by virtqueue_add_sgs()
319 	 */
320 	refcount_set(&req->refcount.refcount, 2);
321 
322 	return req;
323 
324 free:
325 	p9_fcall_fini(&req->tc);
326 	p9_fcall_fini(&req->rc);
327 free_req:
328 	kmem_cache_free(p9_req_cache, req);
329 	return ERR_PTR(-ENOMEM);
330 }
331 
332 /**
333  * p9_tag_lookup - Look up a request by tag.
334  * @c: Client session.
335  * @tag: Transaction ID.
336  *
337  * Context: Any context.
338  * Return: A request, or %NULL if there is no request with that tag.
339  */
340 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
341 {
342 	struct p9_req_t *req;
343 
344 	rcu_read_lock();
345 again:
346 	req = idr_find(&c->reqs, tag);
347 	if (req) {
348 		/* We have to be careful with the req found under rcu_read_lock
349 		 * Thanks to SLAB_TYPESAFE_BY_RCU we can safely try to get the
350 		 * ref again without corrupting other data, then check again
351 		 * that the tag matches once we have the ref
352 		 */
353 		if (!p9_req_try_get(req))
354 			goto again;
355 		if (req->tc.tag != tag) {
356 			p9_req_put(req);
357 			goto again;
358 		}
359 	}
360 	rcu_read_unlock();
361 
362 	return req;
363 }
364 EXPORT_SYMBOL(p9_tag_lookup);
365 
366 /**
367  * p9_tag_remove - Remove a tag.
368  * @c: Client session.
369  * @r: Request of reference.
370  *
371  * Context: Any context.
372  */
373 static int p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
374 {
375 	unsigned long flags;
376 	u16 tag = r->tc.tag;
377 
378 	p9_debug(P9_DEBUG_MUX, "clnt %p req %p tag: %d\n", c, r, tag);
379 	spin_lock_irqsave(&c->lock, flags);
380 	idr_remove(&c->reqs, tag);
381 	spin_unlock_irqrestore(&c->lock, flags);
382 	return p9_req_put(r);
383 }
384 
385 static void p9_req_free(struct kref *ref)
386 {
387 	struct p9_req_t *r = container_of(ref, struct p9_req_t, refcount);
388 	p9_fcall_fini(&r->tc);
389 	p9_fcall_fini(&r->rc);
390 	kmem_cache_free(p9_req_cache, r);
391 }
392 
393 int p9_req_put(struct p9_req_t *r)
394 {
395 	return kref_put(&r->refcount, p9_req_free);
396 }
397 EXPORT_SYMBOL(p9_req_put);
398 
399 /**
400  * p9_tag_cleanup - cleans up tags structure and reclaims resources
401  * @c:  v9fs client struct
402  *
403  * This frees resources associated with the tags structure
404  *
405  */
406 static void p9_tag_cleanup(struct p9_client *c)
407 {
408 	struct p9_req_t *req;
409 	int id;
410 
411 	rcu_read_lock();
412 	idr_for_each_entry(&c->reqs, req, id) {
413 		pr_info("Tag %d still in use\n", id);
414 		if (p9_tag_remove(c, req) == 0)
415 			pr_warn("Packet with tag %d has still references",
416 				req->tc.tag);
417 	}
418 	rcu_read_unlock();
419 }
420 
421 /**
422  * p9_client_cb - call back from transport to client
423  * c: client state
424  * req: request received
425  *
426  */
427 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
428 {
429 	p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc.tag);
430 
431 	/*
432 	 * This barrier is needed to make sure any change made to req before
433 	 * the status change is visible to another thread
434 	 */
435 	smp_wmb();
436 	req->status = status;
437 
438 	wake_up(&req->wq);
439 	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
440 	p9_req_put(req);
441 }
442 EXPORT_SYMBOL(p9_client_cb);
443 
444 /**
445  * p9_parse_header - parse header arguments out of a packet
446  * @pdu: packet to parse
447  * @size: size of packet
448  * @type: type of request
449  * @tag: tag of packet
450  * @rewind: set if we need to rewind offset afterwards
451  */
452 
453 int
454 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type, int16_t *tag,
455 								int rewind)
456 {
457 	int8_t r_type;
458 	int16_t r_tag;
459 	int32_t r_size;
460 	int offset = pdu->offset;
461 	int err;
462 
463 	pdu->offset = 0;
464 
465 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
466 	if (err)
467 		goto rewind_and_exit;
468 
469 	if (type)
470 		*type = r_type;
471 	if (tag)
472 		*tag = r_tag;
473 	if (size)
474 		*size = r_size;
475 
476 	if (pdu->size != r_size || r_size < 7) {
477 		err = -EINVAL;
478 		goto rewind_and_exit;
479 	}
480 
481 	pdu->id = r_type;
482 	pdu->tag = r_tag;
483 
484 	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
485 		 pdu->size, pdu->id, pdu->tag);
486 
487 rewind_and_exit:
488 	if (rewind)
489 		pdu->offset = offset;
490 	return err;
491 }
492 EXPORT_SYMBOL(p9_parse_header);
493 
494 /**
495  * p9_check_errors - check 9p packet for error return and process it
496  * @c: current client instance
497  * @req: request to parse and check for error conditions
498  *
499  * returns error code if one is discovered, otherwise returns 0
500  *
501  * this will have to be more complicated if we have multiple
502  * error packet types
503  */
504 
505 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
506 {
507 	int8_t type;
508 	int err;
509 	int ecode;
510 
511 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
512 	if (req->rc.size >= c->msize) {
513 		p9_debug(P9_DEBUG_ERROR,
514 			 "requested packet size too big: %d\n",
515 			 req->rc.size);
516 		return -EIO;
517 	}
518 	/*
519 	 * dump the response from server
520 	 * This should be after check errors which poplulate pdu_fcall.
521 	 */
522 	trace_9p_protocol_dump(c, &req->rc);
523 	if (err) {
524 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
525 		return err;
526 	}
527 	if (type != P9_RERROR && type != P9_RLERROR)
528 		return 0;
529 
530 	if (!p9_is_proto_dotl(c)) {
531 		char *ename;
532 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
533 				  &ename, &ecode);
534 		if (err)
535 			goto out_err;
536 
537 		if (p9_is_proto_dotu(c) && ecode < 512)
538 			err = -ecode;
539 
540 		if (!err) {
541 			err = p9_errstr2errno(ename, strlen(ename));
542 
543 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
544 				 -ecode, ename);
545 		}
546 		kfree(ename);
547 	} else {
548 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
549 		err = -ecode;
550 
551 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
552 	}
553 
554 	return err;
555 
556 out_err:
557 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
558 
559 	return err;
560 }
561 
562 /**
563  * p9_check_zc_errors - check 9p packet for error return and process it
564  * @c: current client instance
565  * @req: request to parse and check for error conditions
566  * @in_hdrlen: Size of response protocol buffer.
567  *
568  * returns error code if one is discovered, otherwise returns 0
569  *
570  * this will have to be more complicated if we have multiple
571  * error packet types
572  */
573 
574 static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
575 			      struct iov_iter *uidata, int in_hdrlen)
576 {
577 	int err;
578 	int ecode;
579 	int8_t type;
580 	char *ename = NULL;
581 
582 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
583 	/*
584 	 * dump the response from server
585 	 * This should be after parse_header which poplulate pdu_fcall.
586 	 */
587 	trace_9p_protocol_dump(c, &req->rc);
588 	if (err) {
589 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
590 		return err;
591 	}
592 
593 	if (type != P9_RERROR && type != P9_RLERROR)
594 		return 0;
595 
596 	if (!p9_is_proto_dotl(c)) {
597 		/* Error is reported in string format */
598 		int len;
599 		/* 7 = header size for RERROR; */
600 		int inline_len = in_hdrlen - 7;
601 
602 		len = req->rc.size - req->rc.offset;
603 		if (len > (P9_ZC_HDR_SZ - 7)) {
604 			err = -EFAULT;
605 			goto out_err;
606 		}
607 
608 		ename = &req->rc.sdata[req->rc.offset];
609 		if (len > inline_len) {
610 			/* We have error in external buffer */
611 			if (!copy_from_iter_full(ename + inline_len,
612 					     len - inline_len, uidata)) {
613 				err = -EFAULT;
614 				goto out_err;
615 			}
616 		}
617 		ename = NULL;
618 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
619 				  &ename, &ecode);
620 		if (err)
621 			goto out_err;
622 
623 		if (p9_is_proto_dotu(c) && ecode < 512)
624 			err = -ecode;
625 
626 		if (!err) {
627 			err = p9_errstr2errno(ename, strlen(ename));
628 
629 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
630 				 -ecode, ename);
631 		}
632 		kfree(ename);
633 	} else {
634 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
635 		err = -ecode;
636 
637 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
638 	}
639 	return err;
640 
641 out_err:
642 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
643 	return err;
644 }
645 
646 static struct p9_req_t *
647 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
648 
649 /**
650  * p9_client_flush - flush (cancel) a request
651  * @c: client state
652  * @oldreq: request to cancel
653  *
654  * This sents a flush for a particular request and links
655  * the flush request to the original request.  The current
656  * code only supports a single flush request although the protocol
657  * allows for multiple flush requests to be sent for a single request.
658  *
659  */
660 
661 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
662 {
663 	struct p9_req_t *req;
664 	int16_t oldtag;
665 	int err;
666 
667 	err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
668 	if (err)
669 		return err;
670 
671 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
672 
673 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
674 	if (IS_ERR(req))
675 		return PTR_ERR(req);
676 
677 	/*
678 	 * if we haven't received a response for oldreq,
679 	 * remove it from the list
680 	 */
681 	if (oldreq->status == REQ_STATUS_SENT) {
682 		if (c->trans_mod->cancelled)
683 			c->trans_mod->cancelled(c, oldreq);
684 	}
685 
686 	p9_tag_remove(c, req);
687 	return 0;
688 }
689 
690 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
691 					      int8_t type, int req_size,
692 					      const char *fmt, va_list ap)
693 {
694 	int err;
695 	struct p9_req_t *req;
696 
697 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
698 
699 	/* we allow for any status other than disconnected */
700 	if (c->status == Disconnected)
701 		return ERR_PTR(-EIO);
702 
703 	/* if status is begin_disconnected we allow only clunk request */
704 	if ((c->status == BeginDisconnect) && (type != P9_TCLUNK))
705 		return ERR_PTR(-EIO);
706 
707 	req = p9_tag_alloc(c, type, req_size);
708 	if (IS_ERR(req))
709 		return req;
710 
711 	/* marshall the data */
712 	p9pdu_prepare(&req->tc, req->tc.tag, type);
713 	err = p9pdu_vwritef(&req->tc, c->proto_version, fmt, ap);
714 	if (err)
715 		goto reterr;
716 	p9pdu_finalize(c, &req->tc);
717 	trace_9p_client_req(c, type, req->tc.tag);
718 	return req;
719 reterr:
720 	p9_tag_remove(c, req);
721 	/* We have to put also the 2nd reference as it won't be used */
722 	p9_req_put(req);
723 	return ERR_PTR(err);
724 }
725 
726 /**
727  * p9_client_rpc - issue a request and wait for a response
728  * @c: client session
729  * @type: type of request
730  * @fmt: protocol format string (see protocol.c)
731  *
732  * Returns request structure (which client must free using p9_tag_remove)
733  */
734 
735 static struct p9_req_t *
736 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
737 {
738 	va_list ap;
739 	int sigpending, err;
740 	unsigned long flags;
741 	struct p9_req_t *req;
742 
743 	va_start(ap, fmt);
744 	req = p9_client_prepare_req(c, type, c->msize, fmt, ap);
745 	va_end(ap);
746 	if (IS_ERR(req))
747 		return req;
748 
749 	if (signal_pending(current)) {
750 		sigpending = 1;
751 		clear_thread_flag(TIF_SIGPENDING);
752 	} else
753 		sigpending = 0;
754 
755 	err = c->trans_mod->request(c, req);
756 	if (err < 0) {
757 		/* write won't happen */
758 		p9_req_put(req);
759 		if (err != -ERESTARTSYS && err != -EFAULT)
760 			c->status = Disconnected;
761 		goto recalc_sigpending;
762 	}
763 again:
764 	/* Wait for the response */
765 	err = wait_event_killable(req->wq, req->status >= REQ_STATUS_RCVD);
766 
767 	/*
768 	 * Make sure our req is coherent with regard to updates in other
769 	 * threads - echoes to wmb() in the callback
770 	 */
771 	smp_rmb();
772 
773 	if ((err == -ERESTARTSYS) && (c->status == Connected)
774 				  && (type == P9_TFLUSH)) {
775 		sigpending = 1;
776 		clear_thread_flag(TIF_SIGPENDING);
777 		goto again;
778 	}
779 
780 	if (req->status == REQ_STATUS_ERROR) {
781 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
782 		err = req->t_err;
783 	}
784 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
785 		p9_debug(P9_DEBUG_MUX, "flushing\n");
786 		sigpending = 1;
787 		clear_thread_flag(TIF_SIGPENDING);
788 
789 		if (c->trans_mod->cancel(c, req))
790 			p9_client_flush(c, req);
791 
792 		/* if we received the response anyway, don't signal error */
793 		if (req->status == REQ_STATUS_RCVD)
794 			err = 0;
795 	}
796 recalc_sigpending:
797 	if (sigpending) {
798 		spin_lock_irqsave(&current->sighand->siglock, flags);
799 		recalc_sigpending();
800 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
801 	}
802 	if (err < 0)
803 		goto reterr;
804 
805 	err = p9_check_errors(c, req);
806 	trace_9p_client_res(c, type, req->rc.tag, err);
807 	if (!err)
808 		return req;
809 reterr:
810 	p9_tag_remove(c, req);
811 	return ERR_PTR(safe_errno(err));
812 }
813 
814 /**
815  * p9_client_zc_rpc - issue a request and wait for a response
816  * @c: client session
817  * @type: type of request
818  * @uidata: destination for zero copy read
819  * @uodata: source for zero copy write
820  * @inlen: read buffer size
821  * @olen: write buffer size
822  * @hdrlen: reader header size, This is the size of response protocol data
823  * @fmt: protocol format string (see protocol.c)
824  *
825  * Returns request structure (which client must free using p9_tag_remove)
826  */
827 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
828 					 struct iov_iter *uidata,
829 					 struct iov_iter *uodata,
830 					 int inlen, int olen, int in_hdrlen,
831 					 const char *fmt, ...)
832 {
833 	va_list ap;
834 	int sigpending, err;
835 	unsigned long flags;
836 	struct p9_req_t *req;
837 
838 	va_start(ap, fmt);
839 	/*
840 	 * We allocate a inline protocol data of only 4k bytes.
841 	 * The actual content is passed in zero-copy fashion.
842 	 */
843 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, fmt, ap);
844 	va_end(ap);
845 	if (IS_ERR(req))
846 		return req;
847 
848 	if (signal_pending(current)) {
849 		sigpending = 1;
850 		clear_thread_flag(TIF_SIGPENDING);
851 	} else
852 		sigpending = 0;
853 
854 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
855 				       inlen, olen, in_hdrlen);
856 	if (err < 0) {
857 		if (err == -EIO)
858 			c->status = Disconnected;
859 		if (err != -ERESTARTSYS)
860 			goto recalc_sigpending;
861 	}
862 	if (req->status == REQ_STATUS_ERROR) {
863 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
864 		err = req->t_err;
865 	}
866 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
867 		p9_debug(P9_DEBUG_MUX, "flushing\n");
868 		sigpending = 1;
869 		clear_thread_flag(TIF_SIGPENDING);
870 
871 		if (c->trans_mod->cancel(c, req))
872 			p9_client_flush(c, req);
873 
874 		/* if we received the response anyway, don't signal error */
875 		if (req->status == REQ_STATUS_RCVD)
876 			err = 0;
877 	}
878 recalc_sigpending:
879 	if (sigpending) {
880 		spin_lock_irqsave(&current->sighand->siglock, flags);
881 		recalc_sigpending();
882 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
883 	}
884 	if (err < 0)
885 		goto reterr;
886 
887 	err = p9_check_zc_errors(c, req, uidata, in_hdrlen);
888 	trace_9p_client_res(c, type, req->rc.tag, err);
889 	if (!err)
890 		return req;
891 reterr:
892 	p9_tag_remove(c, req);
893 	return ERR_PTR(safe_errno(err));
894 }
895 
896 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
897 {
898 	int ret;
899 	struct p9_fid *fid;
900 
901 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
902 	fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
903 	if (!fid)
904 		return NULL;
905 
906 	memset(&fid->qid, 0, sizeof(struct p9_qid));
907 	fid->mode = -1;
908 	fid->uid = current_fsuid();
909 	fid->clnt = clnt;
910 	fid->rdir = NULL;
911 	fid->fid = 0;
912 
913 	idr_preload(GFP_KERNEL);
914 	spin_lock_irq(&clnt->lock);
915 	ret = idr_alloc_u32(&clnt->fids, fid, &fid->fid, P9_NOFID - 1,
916 			    GFP_NOWAIT);
917 	spin_unlock_irq(&clnt->lock);
918 	idr_preload_end();
919 
920 	if (!ret)
921 		return fid;
922 
923 	kfree(fid);
924 	return NULL;
925 }
926 
927 static void p9_fid_destroy(struct p9_fid *fid)
928 {
929 	struct p9_client *clnt;
930 	unsigned long flags;
931 
932 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
933 	clnt = fid->clnt;
934 	spin_lock_irqsave(&clnt->lock, flags);
935 	idr_remove(&clnt->fids, fid->fid);
936 	spin_unlock_irqrestore(&clnt->lock, flags);
937 	kfree(fid->rdir);
938 	kfree(fid);
939 }
940 
941 static int p9_client_version(struct p9_client *c)
942 {
943 	int err = 0;
944 	struct p9_req_t *req;
945 	char *version = NULL;
946 	int msize;
947 
948 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
949 		 c->msize, c->proto_version);
950 
951 	switch (c->proto_version) {
952 	case p9_proto_2000L:
953 		req = p9_client_rpc(c, P9_TVERSION, "ds",
954 					c->msize, "9P2000.L");
955 		break;
956 	case p9_proto_2000u:
957 		req = p9_client_rpc(c, P9_TVERSION, "ds",
958 					c->msize, "9P2000.u");
959 		break;
960 	case p9_proto_legacy:
961 		req = p9_client_rpc(c, P9_TVERSION, "ds",
962 					c->msize, "9P2000");
963 		break;
964 	default:
965 		return -EINVAL;
966 	}
967 
968 	if (IS_ERR(req))
969 		return PTR_ERR(req);
970 
971 	err = p9pdu_readf(&req->rc, c->proto_version, "ds", &msize, &version);
972 	if (err) {
973 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
974 		trace_9p_protocol_dump(c, &req->rc);
975 		goto error;
976 	}
977 
978 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
979 	if (!strncmp(version, "9P2000.L", 8))
980 		c->proto_version = p9_proto_2000L;
981 	else if (!strncmp(version, "9P2000.u", 8))
982 		c->proto_version = p9_proto_2000u;
983 	else if (!strncmp(version, "9P2000", 6))
984 		c->proto_version = p9_proto_legacy;
985 	else {
986 		err = -EREMOTEIO;
987 		goto error;
988 	}
989 
990 	if (msize < c->msize)
991 		c->msize = msize;
992 
993 error:
994 	kfree(version);
995 	p9_tag_remove(c, req);
996 
997 	return err;
998 }
999 
1000 struct p9_client *p9_client_create(const char *dev_name, char *options)
1001 {
1002 	int err;
1003 	struct p9_client *clnt;
1004 	char *client_id;
1005 
1006 	err = 0;
1007 	clnt = kmalloc(sizeof(struct p9_client), GFP_KERNEL);
1008 	if (!clnt)
1009 		return ERR_PTR(-ENOMEM);
1010 
1011 	clnt->trans_mod = NULL;
1012 	clnt->trans = NULL;
1013 	clnt->fcall_cache = NULL;
1014 
1015 	client_id = utsname()->nodename;
1016 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
1017 
1018 	spin_lock_init(&clnt->lock);
1019 	idr_init(&clnt->fids);
1020 	idr_init(&clnt->reqs);
1021 
1022 	err = parse_opts(options, clnt);
1023 	if (err < 0)
1024 		goto free_client;
1025 
1026 	if (!clnt->trans_mod)
1027 		clnt->trans_mod = v9fs_get_default_trans();
1028 
1029 	if (clnt->trans_mod == NULL) {
1030 		err = -EPROTONOSUPPORT;
1031 		p9_debug(P9_DEBUG_ERROR,
1032 			 "No transport defined or default transport\n");
1033 		goto free_client;
1034 	}
1035 
1036 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
1037 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
1038 
1039 	err = clnt->trans_mod->create(clnt, dev_name, options);
1040 	if (err)
1041 		goto put_trans;
1042 
1043 	if (clnt->msize > clnt->trans_mod->maxsize)
1044 		clnt->msize = clnt->trans_mod->maxsize;
1045 
1046 	err = p9_client_version(clnt);
1047 	if (err)
1048 		goto close_trans;
1049 
1050 	/* P9_HDRSZ + 4 is the smallest packet header we can have that is
1051 	 * followed by data accessed from userspace by read
1052 	 */
1053 	clnt->fcall_cache =
1054 		kmem_cache_create_usercopy("9p-fcall-cache", clnt->msize,
1055 					   0, 0, P9_HDRSZ + 4,
1056 					   clnt->msize - (P9_HDRSZ + 4),
1057 					   NULL);
1058 
1059 	return clnt;
1060 
1061 close_trans:
1062 	clnt->trans_mod->close(clnt);
1063 put_trans:
1064 	v9fs_put_trans(clnt->trans_mod);
1065 free_client:
1066 	kfree(clnt);
1067 	return ERR_PTR(err);
1068 }
1069 EXPORT_SYMBOL(p9_client_create);
1070 
1071 void p9_client_destroy(struct p9_client *clnt)
1072 {
1073 	struct p9_fid *fid;
1074 	int id;
1075 
1076 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1077 
1078 	if (clnt->trans_mod)
1079 		clnt->trans_mod->close(clnt);
1080 
1081 	v9fs_put_trans(clnt->trans_mod);
1082 
1083 	idr_for_each_entry(&clnt->fids, fid, id) {
1084 		pr_info("Found fid %d not clunked\n", fid->fid);
1085 		p9_fid_destroy(fid);
1086 	}
1087 
1088 	p9_tag_cleanup(clnt);
1089 
1090 	kmem_cache_destroy(clnt->fcall_cache);
1091 	kfree(clnt);
1092 }
1093 EXPORT_SYMBOL(p9_client_destroy);
1094 
1095 void p9_client_disconnect(struct p9_client *clnt)
1096 {
1097 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1098 	clnt->status = Disconnected;
1099 }
1100 EXPORT_SYMBOL(p9_client_disconnect);
1101 
1102 void p9_client_begin_disconnect(struct p9_client *clnt)
1103 {
1104 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1105 	clnt->status = BeginDisconnect;
1106 }
1107 EXPORT_SYMBOL(p9_client_begin_disconnect);
1108 
1109 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1110 	const char *uname, kuid_t n_uname, const char *aname)
1111 {
1112 	int err = 0;
1113 	struct p9_req_t *req;
1114 	struct p9_fid *fid;
1115 	struct p9_qid qid;
1116 
1117 
1118 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1119 		 afid ? afid->fid : -1, uname, aname);
1120 	fid = p9_fid_create(clnt);
1121 	if (!fid) {
1122 		err = -ENOMEM;
1123 		goto error;
1124 	}
1125 	fid->uid = n_uname;
1126 
1127 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
1128 			afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
1129 	if (IS_ERR(req)) {
1130 		err = PTR_ERR(req);
1131 		goto error;
1132 	}
1133 
1134 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", &qid);
1135 	if (err) {
1136 		trace_9p_protocol_dump(clnt, &req->rc);
1137 		p9_tag_remove(clnt, req);
1138 		goto error;
1139 	}
1140 
1141 	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
1142 		 qid.type, (unsigned long long)qid.path, qid.version);
1143 
1144 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1145 
1146 	p9_tag_remove(clnt, req);
1147 	return fid;
1148 
1149 error:
1150 	if (fid)
1151 		p9_fid_destroy(fid);
1152 	return ERR_PTR(err);
1153 }
1154 EXPORT_SYMBOL(p9_client_attach);
1155 
1156 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
1157 		const unsigned char * const *wnames, int clone)
1158 {
1159 	int err;
1160 	struct p9_client *clnt;
1161 	struct p9_fid *fid;
1162 	struct p9_qid *wqids;
1163 	struct p9_req_t *req;
1164 	uint16_t nwqids, count;
1165 
1166 	err = 0;
1167 	wqids = NULL;
1168 	clnt = oldfid->clnt;
1169 	if (clone) {
1170 		fid = p9_fid_create(clnt);
1171 		if (!fid) {
1172 			err = -ENOMEM;
1173 			goto error;
1174 		}
1175 
1176 		fid->uid = oldfid->uid;
1177 	} else
1178 		fid = oldfid;
1179 
1180 
1181 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1182 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1183 
1184 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1185 								nwname, wnames);
1186 	if (IS_ERR(req)) {
1187 		err = PTR_ERR(req);
1188 		goto error;
1189 	}
1190 
1191 	err = p9pdu_readf(&req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1192 	if (err) {
1193 		trace_9p_protocol_dump(clnt, &req->rc);
1194 		p9_tag_remove(clnt, req);
1195 		goto clunk_fid;
1196 	}
1197 	p9_tag_remove(clnt, req);
1198 
1199 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1200 
1201 	if (nwqids != nwname) {
1202 		err = -ENOENT;
1203 		goto clunk_fid;
1204 	}
1205 
1206 	for (count = 0; count < nwqids; count++)
1207 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1208 			count, wqids[count].type,
1209 			(unsigned long long)wqids[count].path,
1210 			wqids[count].version);
1211 
1212 	if (nwname)
1213 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1214 	else
1215 		fid->qid = oldfid->qid;
1216 
1217 	kfree(wqids);
1218 	return fid;
1219 
1220 clunk_fid:
1221 	kfree(wqids);
1222 	p9_client_clunk(fid);
1223 	fid = NULL;
1224 
1225 error:
1226 	if (fid && (fid != oldfid))
1227 		p9_fid_destroy(fid);
1228 
1229 	return ERR_PTR(err);
1230 }
1231 EXPORT_SYMBOL(p9_client_walk);
1232 
1233 int p9_client_open(struct p9_fid *fid, int mode)
1234 {
1235 	int err;
1236 	struct p9_client *clnt;
1237 	struct p9_req_t *req;
1238 	struct p9_qid qid;
1239 	int iounit;
1240 
1241 	clnt = fid->clnt;
1242 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1243 		p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1244 	err = 0;
1245 
1246 	if (fid->mode != -1)
1247 		return -EINVAL;
1248 
1249 	if (p9_is_proto_dotl(clnt))
1250 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode);
1251 	else
1252 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
1253 	if (IS_ERR(req)) {
1254 		err = PTR_ERR(req);
1255 		goto error;
1256 	}
1257 
1258 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1259 	if (err) {
1260 		trace_9p_protocol_dump(clnt, &req->rc);
1261 		goto free_and_error;
1262 	}
1263 
1264 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1265 		p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1266 		(unsigned long long)qid.path, qid.version, iounit);
1267 
1268 	fid->mode = mode;
1269 	fid->iounit = iounit;
1270 
1271 free_and_error:
1272 	p9_tag_remove(clnt, req);
1273 error:
1274 	return err;
1275 }
1276 EXPORT_SYMBOL(p9_client_open);
1277 
1278 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags, u32 mode,
1279 		kgid_t gid, struct p9_qid *qid)
1280 {
1281 	int err = 0;
1282 	struct p9_client *clnt;
1283 	struct p9_req_t *req;
1284 	int iounit;
1285 
1286 	p9_debug(P9_DEBUG_9P,
1287 			">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1288 			ofid->fid, name, flags, mode,
1289 		 	from_kgid(&init_user_ns, gid));
1290 	clnt = ofid->clnt;
1291 
1292 	if (ofid->mode != -1)
1293 		return -EINVAL;
1294 
1295 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1296 			mode, gid);
1297 	if (IS_ERR(req)) {
1298 		err = PTR_ERR(req);
1299 		goto error;
1300 	}
1301 
1302 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", qid, &iounit);
1303 	if (err) {
1304 		trace_9p_protocol_dump(clnt, &req->rc);
1305 		goto free_and_error;
1306 	}
1307 
1308 	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1309 			qid->type,
1310 			(unsigned long long)qid->path,
1311 			qid->version, iounit);
1312 
1313 	ofid->mode = mode;
1314 	ofid->iounit = iounit;
1315 
1316 free_and_error:
1317 	p9_tag_remove(clnt, req);
1318 error:
1319 	return err;
1320 }
1321 EXPORT_SYMBOL(p9_client_create_dotl);
1322 
1323 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1324 		     char *extension)
1325 {
1326 	int err;
1327 	struct p9_client *clnt;
1328 	struct p9_req_t *req;
1329 	struct p9_qid qid;
1330 	int iounit;
1331 
1332 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1333 						fid->fid, name, perm, mode);
1334 	err = 0;
1335 	clnt = fid->clnt;
1336 
1337 	if (fid->mode != -1)
1338 		return -EINVAL;
1339 
1340 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1341 				mode, extension);
1342 	if (IS_ERR(req)) {
1343 		err = PTR_ERR(req);
1344 		goto error;
1345 	}
1346 
1347 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1348 	if (err) {
1349 		trace_9p_protocol_dump(clnt, &req->rc);
1350 		goto free_and_error;
1351 	}
1352 
1353 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1354 				qid.type,
1355 				(unsigned long long)qid.path,
1356 				qid.version, iounit);
1357 
1358 	fid->mode = mode;
1359 	fid->iounit = iounit;
1360 
1361 free_and_error:
1362 	p9_tag_remove(clnt, req);
1363 error:
1364 	return err;
1365 }
1366 EXPORT_SYMBOL(p9_client_fcreate);
1367 
1368 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1369 		const char *symtgt, kgid_t gid, struct p9_qid *qid)
1370 {
1371 	int err = 0;
1372 	struct p9_client *clnt;
1373 	struct p9_req_t *req;
1374 
1375 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1376 			dfid->fid, name, symtgt);
1377 	clnt = dfid->clnt;
1378 
1379 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1380 			gid);
1381 	if (IS_ERR(req)) {
1382 		err = PTR_ERR(req);
1383 		goto error;
1384 	}
1385 
1386 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
1387 	if (err) {
1388 		trace_9p_protocol_dump(clnt, &req->rc);
1389 		goto free_and_error;
1390 	}
1391 
1392 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1393 			qid->type, (unsigned long long)qid->path, qid->version);
1394 
1395 free_and_error:
1396 	p9_tag_remove(clnt, req);
1397 error:
1398 	return err;
1399 }
1400 EXPORT_SYMBOL(p9_client_symlink);
1401 
1402 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1403 {
1404 	struct p9_client *clnt;
1405 	struct p9_req_t *req;
1406 
1407 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1408 			dfid->fid, oldfid->fid, newname);
1409 	clnt = dfid->clnt;
1410 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1411 			newname);
1412 	if (IS_ERR(req))
1413 		return PTR_ERR(req);
1414 
1415 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1416 	p9_tag_remove(clnt, req);
1417 	return 0;
1418 }
1419 EXPORT_SYMBOL(p9_client_link);
1420 
1421 int p9_client_fsync(struct p9_fid *fid, int datasync)
1422 {
1423 	int err;
1424 	struct p9_client *clnt;
1425 	struct p9_req_t *req;
1426 
1427 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1428 			fid->fid, datasync);
1429 	err = 0;
1430 	clnt = fid->clnt;
1431 
1432 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1433 	if (IS_ERR(req)) {
1434 		err = PTR_ERR(req);
1435 		goto error;
1436 	}
1437 
1438 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1439 
1440 	p9_tag_remove(clnt, req);
1441 
1442 error:
1443 	return err;
1444 }
1445 EXPORT_SYMBOL(p9_client_fsync);
1446 
1447 int p9_client_clunk(struct p9_fid *fid)
1448 {
1449 	int err;
1450 	struct p9_client *clnt;
1451 	struct p9_req_t *req;
1452 	int retries = 0;
1453 
1454 	if (!fid) {
1455 		pr_warn("%s (%d): Trying to clunk with NULL fid\n",
1456 			__func__, task_pid_nr(current));
1457 		dump_stack();
1458 		return 0;
1459 	}
1460 
1461 again:
1462 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n", fid->fid,
1463 								retries);
1464 	err = 0;
1465 	clnt = fid->clnt;
1466 
1467 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1468 	if (IS_ERR(req)) {
1469 		err = PTR_ERR(req);
1470 		goto error;
1471 	}
1472 
1473 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1474 
1475 	p9_tag_remove(clnt, req);
1476 error:
1477 	/*
1478 	 * Fid is not valid even after a failed clunk
1479 	 * If interrupted, retry once then give up and
1480 	 * leak fid until umount.
1481 	 */
1482 	if (err == -ERESTARTSYS) {
1483 		if (retries++ == 0)
1484 			goto again;
1485 	} else
1486 		p9_fid_destroy(fid);
1487 	return err;
1488 }
1489 EXPORT_SYMBOL(p9_client_clunk);
1490 
1491 int p9_client_remove(struct p9_fid *fid)
1492 {
1493 	int err;
1494 	struct p9_client *clnt;
1495 	struct p9_req_t *req;
1496 
1497 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1498 	err = 0;
1499 	clnt = fid->clnt;
1500 
1501 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1502 	if (IS_ERR(req)) {
1503 		err = PTR_ERR(req);
1504 		goto error;
1505 	}
1506 
1507 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1508 
1509 	p9_tag_remove(clnt, req);
1510 error:
1511 	if (err == -ERESTARTSYS)
1512 		p9_client_clunk(fid);
1513 	else
1514 		p9_fid_destroy(fid);
1515 	return err;
1516 }
1517 EXPORT_SYMBOL(p9_client_remove);
1518 
1519 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1520 {
1521 	int err = 0;
1522 	struct p9_req_t *req;
1523 	struct p9_client *clnt;
1524 
1525 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1526 		   dfid->fid, name, flags);
1527 
1528 	clnt = dfid->clnt;
1529 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1530 	if (IS_ERR(req)) {
1531 		err = PTR_ERR(req);
1532 		goto error;
1533 	}
1534 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1535 
1536 	p9_tag_remove(clnt, req);
1537 error:
1538 	return err;
1539 }
1540 EXPORT_SYMBOL(p9_client_unlinkat);
1541 
1542 int
1543 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1544 {
1545 	struct p9_client *clnt = fid->clnt;
1546 	struct p9_req_t *req;
1547 	int total = 0;
1548 	*err = 0;
1549 
1550 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n",
1551 		   fid->fid, (unsigned long long) offset, (int)iov_iter_count(to));
1552 
1553 	while (iov_iter_count(to)) {
1554 		int count = iov_iter_count(to);
1555 		int rsize, non_zc = 0;
1556 		char *dataptr;
1557 
1558 		rsize = fid->iounit;
1559 		if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1560 			rsize = clnt->msize - P9_IOHDRSZ;
1561 
1562 		if (count < rsize)
1563 			rsize = count;
1564 
1565 		/* Don't bother zerocopy for small IO (< 1024) */
1566 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1567 			/*
1568 			 * response header len is 11
1569 			 * PDU Header(7) + IO Size (4)
1570 			 */
1571 			req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1572 					       0, 11, "dqd", fid->fid,
1573 					       offset, rsize);
1574 		} else {
1575 			non_zc = 1;
1576 			req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1577 					    rsize);
1578 		}
1579 		if (IS_ERR(req)) {
1580 			*err = PTR_ERR(req);
1581 			break;
1582 		}
1583 
1584 		*err = p9pdu_readf(&req->rc, clnt->proto_version,
1585 				   "D", &count, &dataptr);
1586 		if (*err) {
1587 			trace_9p_protocol_dump(clnt, &req->rc);
1588 			p9_tag_remove(clnt, req);
1589 			break;
1590 		}
1591 		if (rsize < count) {
1592 			pr_err("bogus RREAD count (%d > %d)\n", count, rsize);
1593 			count = rsize;
1594 		}
1595 
1596 		p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1597 		if (!count) {
1598 			p9_tag_remove(clnt, req);
1599 			break;
1600 		}
1601 
1602 		if (non_zc) {
1603 			int n = copy_to_iter(dataptr, count, to);
1604 			total += n;
1605 			offset += n;
1606 			if (n != count) {
1607 				*err = -EFAULT;
1608 				p9_tag_remove(clnt, req);
1609 				break;
1610 			}
1611 		} else {
1612 			iov_iter_advance(to, count);
1613 			total += count;
1614 			offset += count;
1615 		}
1616 		p9_tag_remove(clnt, req);
1617 	}
1618 	return total;
1619 }
1620 EXPORT_SYMBOL(p9_client_read);
1621 
1622 int
1623 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1624 {
1625 	struct p9_client *clnt = fid->clnt;
1626 	struct p9_req_t *req;
1627 	int total = 0;
1628 	*err = 0;
1629 
1630 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n",
1631 				fid->fid, (unsigned long long) offset,
1632 				iov_iter_count(from));
1633 
1634 	while (iov_iter_count(from)) {
1635 		int count = iov_iter_count(from);
1636 		int rsize = fid->iounit;
1637 		if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1638 			rsize = clnt->msize - P9_IOHDRSZ;
1639 
1640 		if (count < rsize)
1641 			rsize = count;
1642 
1643 		/* Don't bother zerocopy for small IO (< 1024) */
1644 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1645 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1646 					       rsize, P9_ZC_HDR_SZ, "dqd",
1647 					       fid->fid, offset, rsize);
1648 		} else {
1649 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1650 						    offset, rsize, from);
1651 		}
1652 		if (IS_ERR(req)) {
1653 			*err = PTR_ERR(req);
1654 			break;
1655 		}
1656 
1657 		*err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &count);
1658 		if (*err) {
1659 			trace_9p_protocol_dump(clnt, &req->rc);
1660 			p9_tag_remove(clnt, req);
1661 			break;
1662 		}
1663 		if (rsize < count) {
1664 			pr_err("bogus RWRITE count (%d > %d)\n", count, rsize);
1665 			count = rsize;
1666 		}
1667 
1668 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1669 
1670 		p9_tag_remove(clnt, req);
1671 		iov_iter_advance(from, count);
1672 		total += count;
1673 		offset += count;
1674 	}
1675 	return total;
1676 }
1677 EXPORT_SYMBOL(p9_client_write);
1678 
1679 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1680 {
1681 	int err;
1682 	struct p9_client *clnt;
1683 	struct p9_wstat *ret = kmalloc(sizeof(struct p9_wstat), GFP_KERNEL);
1684 	struct p9_req_t *req;
1685 	u16 ignored;
1686 
1687 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1688 
1689 	if (!ret)
1690 		return ERR_PTR(-ENOMEM);
1691 
1692 	err = 0;
1693 	clnt = fid->clnt;
1694 
1695 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1696 	if (IS_ERR(req)) {
1697 		err = PTR_ERR(req);
1698 		goto error;
1699 	}
1700 
1701 	err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
1702 	if (err) {
1703 		trace_9p_protocol_dump(clnt, &req->rc);
1704 		p9_tag_remove(clnt, req);
1705 		goto error;
1706 	}
1707 
1708 	p9_debug(P9_DEBUG_9P,
1709 		"<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1710 		"<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1711 		"<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1712 		"<<<    uid=%d gid=%d n_muid=%d\n",
1713 		ret->size, ret->type, ret->dev, ret->qid.type,
1714 		(unsigned long long)ret->qid.path, ret->qid.version, ret->mode,
1715 		ret->atime, ret->mtime, (unsigned long long)ret->length,
1716 		ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1717 		from_kuid(&init_user_ns, ret->n_uid),
1718 		from_kgid(&init_user_ns, ret->n_gid),
1719 		from_kuid(&init_user_ns, ret->n_muid));
1720 
1721 	p9_tag_remove(clnt, req);
1722 	return ret;
1723 
1724 error:
1725 	kfree(ret);
1726 	return ERR_PTR(err);
1727 }
1728 EXPORT_SYMBOL(p9_client_stat);
1729 
1730 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1731 							u64 request_mask)
1732 {
1733 	int err;
1734 	struct p9_client *clnt;
1735 	struct p9_stat_dotl *ret = kmalloc(sizeof(struct p9_stat_dotl),
1736 								GFP_KERNEL);
1737 	struct p9_req_t *req;
1738 
1739 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1740 							fid->fid, request_mask);
1741 
1742 	if (!ret)
1743 		return ERR_PTR(-ENOMEM);
1744 
1745 	err = 0;
1746 	clnt = fid->clnt;
1747 
1748 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1749 	if (IS_ERR(req)) {
1750 		err = PTR_ERR(req);
1751 		goto error;
1752 	}
1753 
1754 	err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
1755 	if (err) {
1756 		trace_9p_protocol_dump(clnt, &req->rc);
1757 		p9_tag_remove(clnt, req);
1758 		goto error;
1759 	}
1760 
1761 	p9_debug(P9_DEBUG_9P,
1762 		"<<< RGETATTR st_result_mask=%lld\n"
1763 		"<<< qid=%x.%llx.%x\n"
1764 		"<<< st_mode=%8.8x st_nlink=%llu\n"
1765 		"<<< st_uid=%d st_gid=%d\n"
1766 		"<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1767 		"<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1768 		"<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1769 		"<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1770 		"<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1771 		"<<< st_gen=%lld st_data_version=%lld\n",
1772 		ret->st_result_mask, ret->qid.type, ret->qid.path,
1773 		ret->qid.version, ret->st_mode, ret->st_nlink,
1774 		from_kuid(&init_user_ns, ret->st_uid),
1775 		from_kgid(&init_user_ns, ret->st_gid),
1776 		ret->st_rdev, ret->st_size, ret->st_blksize,
1777 		ret->st_blocks, ret->st_atime_sec, ret->st_atime_nsec,
1778 		ret->st_mtime_sec, ret->st_mtime_nsec, ret->st_ctime_sec,
1779 		ret->st_ctime_nsec, ret->st_btime_sec, ret->st_btime_nsec,
1780 		ret->st_gen, ret->st_data_version);
1781 
1782 	p9_tag_remove(clnt, req);
1783 	return ret;
1784 
1785 error:
1786 	kfree(ret);
1787 	return ERR_PTR(err);
1788 }
1789 EXPORT_SYMBOL(p9_client_getattr_dotl);
1790 
1791 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1792 {
1793 	int ret;
1794 
1795 	/* NOTE: size shouldn't include its own length */
1796 	/* size[2] type[2] dev[4] qid[13] */
1797 	/* mode[4] atime[4] mtime[4] length[8]*/
1798 	/* name[s] uid[s] gid[s] muid[s] */
1799 	ret = 2+4+13+4+4+4+8+2+2+2+2;
1800 
1801 	if (wst->name)
1802 		ret += strlen(wst->name);
1803 	if (wst->uid)
1804 		ret += strlen(wst->uid);
1805 	if (wst->gid)
1806 		ret += strlen(wst->gid);
1807 	if (wst->muid)
1808 		ret += strlen(wst->muid);
1809 
1810 	if ((proto_version == p9_proto_2000u) ||
1811 		(proto_version == p9_proto_2000L)) {
1812 		ret += 2+4+4+4;	/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1813 		if (wst->extension)
1814 			ret += strlen(wst->extension);
1815 	}
1816 
1817 	return ret;
1818 }
1819 
1820 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1821 {
1822 	int err;
1823 	struct p9_req_t *req;
1824 	struct p9_client *clnt;
1825 
1826 	err = 0;
1827 	clnt = fid->clnt;
1828 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1829 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n", fid->fid);
1830 	p9_debug(P9_DEBUG_9P,
1831 		"     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1832 		"     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1833 		"     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1834 		"     uid=%d gid=%d n_muid=%d\n",
1835 		wst->size, wst->type, wst->dev, wst->qid.type,
1836 		(unsigned long long)wst->qid.path, wst->qid.version, wst->mode,
1837 		wst->atime, wst->mtime, (unsigned long long)wst->length,
1838 		wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1839 		from_kuid(&init_user_ns, wst->n_uid),
1840 		from_kgid(&init_user_ns, wst->n_gid),
1841 		from_kuid(&init_user_ns, wst->n_muid));
1842 
1843 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS", fid->fid, wst->size+2, wst);
1844 	if (IS_ERR(req)) {
1845 		err = PTR_ERR(req);
1846 		goto error;
1847 	}
1848 
1849 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1850 
1851 	p9_tag_remove(clnt, req);
1852 error:
1853 	return err;
1854 }
1855 EXPORT_SYMBOL(p9_client_wstat);
1856 
1857 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1858 {
1859 	int err;
1860 	struct p9_req_t *req;
1861 	struct p9_client *clnt;
1862 
1863 	err = 0;
1864 	clnt = fid->clnt;
1865 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1866 	p9_debug(P9_DEBUG_9P,
1867 		"    valid=%x mode=%x uid=%d gid=%d size=%lld\n"
1868 		"    atime_sec=%lld atime_nsec=%lld\n"
1869 		"    mtime_sec=%lld mtime_nsec=%lld\n",
1870 		p9attr->valid, p9attr->mode,
1871 		from_kuid(&init_user_ns, p9attr->uid),
1872 		from_kgid(&init_user_ns, p9attr->gid),
1873 		p9attr->size, p9attr->atime_sec, p9attr->atime_nsec,
1874 		p9attr->mtime_sec, p9attr->mtime_nsec);
1875 
1876 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1877 
1878 	if (IS_ERR(req)) {
1879 		err = PTR_ERR(req);
1880 		goto error;
1881 	}
1882 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1883 	p9_tag_remove(clnt, req);
1884 error:
1885 	return err;
1886 }
1887 EXPORT_SYMBOL(p9_client_setattr);
1888 
1889 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1890 {
1891 	int err;
1892 	struct p9_req_t *req;
1893 	struct p9_client *clnt;
1894 
1895 	err = 0;
1896 	clnt = fid->clnt;
1897 
1898 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1899 
1900 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1901 	if (IS_ERR(req)) {
1902 		err = PTR_ERR(req);
1903 		goto error;
1904 	}
1905 
1906 	err = p9pdu_readf(&req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1907 			  &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1908 			  &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1909 	if (err) {
1910 		trace_9p_protocol_dump(clnt, &req->rc);
1911 		p9_tag_remove(clnt, req);
1912 		goto error;
1913 	}
1914 
1915 	p9_debug(P9_DEBUG_9P, "<<< RSTATFS fid %d type 0x%lx bsize %ld "
1916 		"blocks %llu bfree %llu bavail %llu files %llu ffree %llu "
1917 		"fsid %llu namelen %ld\n",
1918 		fid->fid, (long unsigned int)sb->type, (long int)sb->bsize,
1919 		sb->blocks, sb->bfree, sb->bavail, sb->files,  sb->ffree,
1920 		sb->fsid, (long int)sb->namelen);
1921 
1922 	p9_tag_remove(clnt, req);
1923 error:
1924 	return err;
1925 }
1926 EXPORT_SYMBOL(p9_client_statfs);
1927 
1928 int p9_client_rename(struct p9_fid *fid,
1929 		     struct p9_fid *newdirfid, const char *name)
1930 {
1931 	int err;
1932 	struct p9_req_t *req;
1933 	struct p9_client *clnt;
1934 
1935 	err = 0;
1936 	clnt = fid->clnt;
1937 
1938 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1939 			fid->fid, newdirfid->fid, name);
1940 
1941 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1942 			newdirfid->fid, name);
1943 	if (IS_ERR(req)) {
1944 		err = PTR_ERR(req);
1945 		goto error;
1946 	}
1947 
1948 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1949 
1950 	p9_tag_remove(clnt, req);
1951 error:
1952 	return err;
1953 }
1954 EXPORT_SYMBOL(p9_client_rename);
1955 
1956 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
1957 		       struct p9_fid *newdirfid, const char *new_name)
1958 {
1959 	int err;
1960 	struct p9_req_t *req;
1961 	struct p9_client *clnt;
1962 
1963 	err = 0;
1964 	clnt = olddirfid->clnt;
1965 
1966 	p9_debug(P9_DEBUG_9P, ">>> TRENAMEAT olddirfid %d old name %s"
1967 		   " newdirfid %d new name %s\n", olddirfid->fid, old_name,
1968 		   newdirfid->fid, new_name);
1969 
1970 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
1971 			    old_name, newdirfid->fid, new_name);
1972 	if (IS_ERR(req)) {
1973 		err = PTR_ERR(req);
1974 		goto error;
1975 	}
1976 
1977 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
1978 		   newdirfid->fid, new_name);
1979 
1980 	p9_tag_remove(clnt, req);
1981 error:
1982 	return err;
1983 }
1984 EXPORT_SYMBOL(p9_client_renameat);
1985 
1986 /*
1987  * An xattrwalk without @attr_name gives the fid for the lisxattr namespace
1988  */
1989 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
1990 				const char *attr_name, u64 *attr_size)
1991 {
1992 	int err;
1993 	struct p9_req_t *req;
1994 	struct p9_client *clnt;
1995 	struct p9_fid *attr_fid;
1996 
1997 	err = 0;
1998 	clnt = file_fid->clnt;
1999 	attr_fid = p9_fid_create(clnt);
2000 	if (!attr_fid) {
2001 		err = -ENOMEM;
2002 		goto error;
2003 	}
2004 	p9_debug(P9_DEBUG_9P,
2005 		">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
2006 		file_fid->fid, attr_fid->fid, attr_name);
2007 
2008 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
2009 			file_fid->fid, attr_fid->fid, attr_name);
2010 	if (IS_ERR(req)) {
2011 		err = PTR_ERR(req);
2012 		goto error;
2013 	}
2014 	err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
2015 	if (err) {
2016 		trace_9p_protocol_dump(clnt, &req->rc);
2017 		p9_tag_remove(clnt, req);
2018 		goto clunk_fid;
2019 	}
2020 	p9_tag_remove(clnt, req);
2021 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
2022 		attr_fid->fid, *attr_size);
2023 	return attr_fid;
2024 clunk_fid:
2025 	p9_client_clunk(attr_fid);
2026 	attr_fid = NULL;
2027 error:
2028 	if (attr_fid && (attr_fid != file_fid))
2029 		p9_fid_destroy(attr_fid);
2030 
2031 	return ERR_PTR(err);
2032 }
2033 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
2034 
2035 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
2036 			u64 attr_size, int flags)
2037 {
2038 	int err;
2039 	struct p9_req_t *req;
2040 	struct p9_client *clnt;
2041 
2042 	p9_debug(P9_DEBUG_9P,
2043 		">>> TXATTRCREATE fid %d name  %s size %lld flag %d\n",
2044 		fid->fid, name, (long long)attr_size, flags);
2045 	err = 0;
2046 	clnt = fid->clnt;
2047 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
2048 			fid->fid, name, attr_size, flags);
2049 	if (IS_ERR(req)) {
2050 		err = PTR_ERR(req);
2051 		goto error;
2052 	}
2053 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
2054 	p9_tag_remove(clnt, req);
2055 error:
2056 	return err;
2057 }
2058 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
2059 
2060 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
2061 {
2062 	int err, rsize, non_zc = 0;
2063 	struct p9_client *clnt;
2064 	struct p9_req_t *req;
2065 	char *dataptr;
2066 	struct kvec kv = {.iov_base = data, .iov_len = count};
2067 	struct iov_iter to;
2068 
2069 	iov_iter_kvec(&to, READ | ITER_KVEC, &kv, 1, count);
2070 
2071 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
2072 				fid->fid, (unsigned long long) offset, count);
2073 
2074 	err = 0;
2075 	clnt = fid->clnt;
2076 
2077 	rsize = fid->iounit;
2078 	if (!rsize || rsize > clnt->msize-P9_READDIRHDRSZ)
2079 		rsize = clnt->msize - P9_READDIRHDRSZ;
2080 
2081 	if (count < rsize)
2082 		rsize = count;
2083 
2084 	/* Don't bother zerocopy for small IO (< 1024) */
2085 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2086 		/*
2087 		 * response header len is 11
2088 		 * PDU Header(7) + IO Size (4)
2089 		 */
2090 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2091 				       11, "dqd", fid->fid, offset, rsize);
2092 	} else {
2093 		non_zc = 1;
2094 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2095 				    offset, rsize);
2096 	}
2097 	if (IS_ERR(req)) {
2098 		err = PTR_ERR(req);
2099 		goto error;
2100 	}
2101 
2102 	err = p9pdu_readf(&req->rc, clnt->proto_version, "D", &count, &dataptr);
2103 	if (err) {
2104 		trace_9p_protocol_dump(clnt, &req->rc);
2105 		goto free_and_error;
2106 	}
2107 	if (rsize < count) {
2108 		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
2109 		count = rsize;
2110 	}
2111 
2112 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
2113 
2114 	if (non_zc)
2115 		memmove(data, dataptr, count);
2116 
2117 	p9_tag_remove(clnt, req);
2118 	return count;
2119 
2120 free_and_error:
2121 	p9_tag_remove(clnt, req);
2122 error:
2123 	return err;
2124 }
2125 EXPORT_SYMBOL(p9_client_readdir);
2126 
2127 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2128 			dev_t rdev, kgid_t gid, struct p9_qid *qid)
2129 {
2130 	int err;
2131 	struct p9_client *clnt;
2132 	struct p9_req_t *req;
2133 
2134 	err = 0;
2135 	clnt = fid->clnt;
2136 	p9_debug(P9_DEBUG_9P, ">>> TMKNOD fid %d name %s mode %d major %d "
2137 		"minor %d\n", fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2138 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2139 		MAJOR(rdev), MINOR(rdev), gid);
2140 	if (IS_ERR(req))
2141 		return PTR_ERR(req);
2142 
2143 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2144 	if (err) {
2145 		trace_9p_protocol_dump(clnt, &req->rc);
2146 		goto error;
2147 	}
2148 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n", qid->type,
2149 				(unsigned long long)qid->path, qid->version);
2150 
2151 error:
2152 	p9_tag_remove(clnt, req);
2153 	return err;
2154 
2155 }
2156 EXPORT_SYMBOL(p9_client_mknod_dotl);
2157 
2158 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2159 				kgid_t gid, struct p9_qid *qid)
2160 {
2161 	int err;
2162 	struct p9_client *clnt;
2163 	struct p9_req_t *req;
2164 
2165 	err = 0;
2166 	clnt = fid->clnt;
2167 	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
2168 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
2169 	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg", fid->fid, name, mode,
2170 		gid);
2171 	if (IS_ERR(req))
2172 		return PTR_ERR(req);
2173 
2174 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2175 	if (err) {
2176 		trace_9p_protocol_dump(clnt, &req->rc);
2177 		goto error;
2178 	}
2179 	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
2180 				(unsigned long long)qid->path, qid->version);
2181 
2182 error:
2183 	p9_tag_remove(clnt, req);
2184 	return err;
2185 
2186 }
2187 EXPORT_SYMBOL(p9_client_mkdir_dotl);
2188 
2189 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
2190 {
2191 	int err;
2192 	struct p9_client *clnt;
2193 	struct p9_req_t *req;
2194 
2195 	err = 0;
2196 	clnt = fid->clnt;
2197 	p9_debug(P9_DEBUG_9P, ">>> TLOCK fid %d type %i flags %d "
2198 			"start %lld length %lld proc_id %d client_id %s\n",
2199 			fid->fid, flock->type, flock->flags, flock->start,
2200 			flock->length, flock->proc_id, flock->client_id);
2201 
2202 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2203 				flock->flags, flock->start, flock->length,
2204 					flock->proc_id, flock->client_id);
2205 
2206 	if (IS_ERR(req))
2207 		return PTR_ERR(req);
2208 
2209 	err = p9pdu_readf(&req->rc, clnt->proto_version, "b", status);
2210 	if (err) {
2211 		trace_9p_protocol_dump(clnt, &req->rc);
2212 		goto error;
2213 	}
2214 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2215 error:
2216 	p9_tag_remove(clnt, req);
2217 	return err;
2218 
2219 }
2220 EXPORT_SYMBOL(p9_client_lock_dotl);
2221 
2222 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2223 {
2224 	int err;
2225 	struct p9_client *clnt;
2226 	struct p9_req_t *req;
2227 
2228 	err = 0;
2229 	clnt = fid->clnt;
2230 	p9_debug(P9_DEBUG_9P, ">>> TGETLOCK fid %d, type %i start %lld "
2231 		"length %lld proc_id %d client_id %s\n", fid->fid, glock->type,
2232 		glock->start, glock->length, glock->proc_id, glock->client_id);
2233 
2234 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,  glock->type,
2235 		glock->start, glock->length, glock->proc_id, glock->client_id);
2236 
2237 	if (IS_ERR(req))
2238 		return PTR_ERR(req);
2239 
2240 	err = p9pdu_readf(&req->rc, clnt->proto_version, "bqqds", &glock->type,
2241 			  &glock->start, &glock->length, &glock->proc_id,
2242 			  &glock->client_id);
2243 	if (err) {
2244 		trace_9p_protocol_dump(clnt, &req->rc);
2245 		goto error;
2246 	}
2247 	p9_debug(P9_DEBUG_9P, "<<< RGETLOCK type %i start %lld length %lld "
2248 		"proc_id %d client_id %s\n", glock->type, glock->start,
2249 		glock->length, glock->proc_id, glock->client_id);
2250 error:
2251 	p9_tag_remove(clnt, req);
2252 	return err;
2253 }
2254 EXPORT_SYMBOL(p9_client_getlock_dotl);
2255 
2256 int p9_client_readlink(struct p9_fid *fid, char **target)
2257 {
2258 	int err;
2259 	struct p9_client *clnt;
2260 	struct p9_req_t *req;
2261 
2262 	err = 0;
2263 	clnt = fid->clnt;
2264 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2265 
2266 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2267 	if (IS_ERR(req))
2268 		return PTR_ERR(req);
2269 
2270 	err = p9pdu_readf(&req->rc, clnt->proto_version, "s", target);
2271 	if (err) {
2272 		trace_9p_protocol_dump(clnt, &req->rc);
2273 		goto error;
2274 	}
2275 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2276 error:
2277 	p9_tag_remove(clnt, req);
2278 	return err;
2279 }
2280 EXPORT_SYMBOL(p9_client_readlink);
2281 
2282 int __init p9_client_init(void)
2283 {
2284 	p9_req_cache = KMEM_CACHE(p9_req_t, SLAB_TYPESAFE_BY_RCU);
2285 	return p9_req_cache ? 0 : -ENOMEM;
2286 }
2287 
2288 void __exit p9_client_exit(void)
2289 {
2290 	kmem_cache_destroy(p9_req_cache);
2291 }
2292