xref: /linux/net/9p/client.c (revision 8b11ff098af42b1fa57fc817daadd53c8b244a0c)
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, 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(c, 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(c, r);
371 }
372 
373 int p9_req_put(struct p9_client *c, struct p9_req_t *r)
374 {
375 	if (refcount_dec_and_test(&r->refcount)) {
376 		p9_fcall_fini(&r->tc);
377 		p9_fcall_fini(&r->rc);
378 		kmem_cache_free(p9_req_cache, r);
379 		return 1;
380 	}
381 	return 0;
382 }
383 EXPORT_SYMBOL(p9_req_put);
384 
385 /**
386  * p9_tag_cleanup - cleans up tags structure and reclaims resources
387  * @c:  v9fs client struct
388  *
389  * This frees resources associated with the tags structure
390  *
391  */
392 static void p9_tag_cleanup(struct p9_client *c)
393 {
394 	struct p9_req_t *req;
395 	int id;
396 
397 	rcu_read_lock();
398 	idr_for_each_entry(&c->reqs, req, id) {
399 		pr_info("Tag %d still in use\n", id);
400 		if (p9_tag_remove(c, req) == 0)
401 			pr_warn("Packet with tag %d has still references",
402 				req->tc.tag);
403 	}
404 	rcu_read_unlock();
405 }
406 
407 /**
408  * p9_client_cb - call back from transport to client
409  * @c: client state
410  * @req: request received
411  * @status: request status, one of REQ_STATUS_*
412  *
413  */
414 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
415 {
416 	p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc.tag);
417 
418 	/* This barrier is needed to make sure any change made to req before
419 	 * the status change is visible to another thread
420 	 */
421 	smp_wmb();
422 	req->status = status;
423 
424 	wake_up(&req->wq);
425 	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
426 	p9_req_put(c, req);
427 }
428 EXPORT_SYMBOL(p9_client_cb);
429 
430 /**
431  * p9_parse_header - parse header arguments out of a packet
432  * @pdu: packet to parse
433  * @size: size of packet
434  * @type: type of request
435  * @tag: tag of packet
436  * @rewind: set if we need to rewind offset afterwards
437  */
438 
439 int
440 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type,
441 		int16_t *tag, int rewind)
442 {
443 	s8 r_type;
444 	s16 r_tag;
445 	s32 r_size;
446 	int offset = pdu->offset;
447 	int err;
448 
449 	pdu->offset = 0;
450 
451 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
452 	if (err)
453 		goto rewind_and_exit;
454 
455 	if (type)
456 		*type = r_type;
457 	if (tag)
458 		*tag = r_tag;
459 	if (size)
460 		*size = r_size;
461 
462 	if (pdu->size != r_size || r_size < 7) {
463 		err = -EINVAL;
464 		goto rewind_and_exit;
465 	}
466 
467 	pdu->id = r_type;
468 	pdu->tag = r_tag;
469 
470 	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
471 		 pdu->size, pdu->id, pdu->tag);
472 
473 rewind_and_exit:
474 	if (rewind)
475 		pdu->offset = offset;
476 	return err;
477 }
478 EXPORT_SYMBOL(p9_parse_header);
479 
480 /**
481  * p9_check_errors - check 9p packet for error return and process it
482  * @c: current client instance
483  * @req: request to parse and check for error conditions
484  *
485  * returns error code if one is discovered, otherwise returns 0
486  *
487  * this will have to be more complicated if we have multiple
488  * error packet types
489  */
490 
491 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
492 {
493 	s8 type;
494 	int err;
495 	int ecode;
496 
497 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
498 	if (req->rc.size >= c->msize) {
499 		p9_debug(P9_DEBUG_ERROR,
500 			 "requested packet size too big: %d\n",
501 			 req->rc.size);
502 		return -EIO;
503 	}
504 	/* dump the response from server
505 	 * This should be after check errors which poplulate pdu_fcall.
506 	 */
507 	trace_9p_protocol_dump(c, &req->rc);
508 	if (err) {
509 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
510 		return err;
511 	}
512 	if (type != P9_RERROR && type != P9_RLERROR)
513 		return 0;
514 
515 	if (!p9_is_proto_dotl(c)) {
516 		char *ename;
517 
518 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
519 				  &ename, &ecode);
520 		if (err)
521 			goto out_err;
522 
523 		if (p9_is_proto_dotu(c) && ecode < 512)
524 			err = -ecode;
525 
526 		if (!err) {
527 			err = p9_errstr2errno(ename, strlen(ename));
528 
529 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
530 				 -ecode, ename);
531 		}
532 		kfree(ename);
533 	} else {
534 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
535 		if (err)
536 			goto out_err;
537 		err = -ecode;
538 
539 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
540 	}
541 
542 	return err;
543 
544 out_err:
545 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
546 
547 	return err;
548 }
549 
550 /**
551  * p9_check_zc_errors - check 9p packet for error return and process it
552  * @c: current client instance
553  * @req: request to parse and check for error conditions
554  * @uidata: external buffer containing error
555  * @in_hdrlen: Size of response protocol buffer.
556  *
557  * returns error code if one is discovered, otherwise returns 0
558  *
559  * this will have to be more complicated if we have multiple
560  * error packet types
561  */
562 
563 static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
564 			      struct iov_iter *uidata, int in_hdrlen)
565 {
566 	int err;
567 	int ecode;
568 	s8 type;
569 	char *ename = NULL;
570 
571 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
572 	/* dump the response from server
573 	 * This should be after parse_header which poplulate pdu_fcall.
574 	 */
575 	trace_9p_protocol_dump(c, &req->rc);
576 	if (err) {
577 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
578 		return err;
579 	}
580 
581 	if (type != P9_RERROR && type != P9_RLERROR)
582 		return 0;
583 
584 	if (!p9_is_proto_dotl(c)) {
585 		/* Error is reported in string format */
586 		int len;
587 		/* 7 = header size for RERROR; */
588 		int inline_len = in_hdrlen - 7;
589 
590 		len = req->rc.size - req->rc.offset;
591 		if (len > (P9_ZC_HDR_SZ - 7)) {
592 			err = -EFAULT;
593 			goto out_err;
594 		}
595 
596 		ename = &req->rc.sdata[req->rc.offset];
597 		if (len > inline_len) {
598 			/* We have error in external buffer */
599 			if (!copy_from_iter_full(ename + inline_len,
600 						 len - inline_len, uidata)) {
601 				err = -EFAULT;
602 				goto out_err;
603 			}
604 		}
605 		ename = NULL;
606 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
607 				  &ename, &ecode);
608 		if (err)
609 			goto out_err;
610 
611 		if (p9_is_proto_dotu(c) && ecode < 512)
612 			err = -ecode;
613 
614 		if (!err) {
615 			err = p9_errstr2errno(ename, strlen(ename));
616 
617 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
618 				 -ecode, ename);
619 		}
620 		kfree(ename);
621 	} else {
622 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
623 		err = -ecode;
624 
625 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
626 	}
627 	return err;
628 
629 out_err:
630 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
631 	return err;
632 }
633 
634 static struct p9_req_t *
635 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
636 
637 /**
638  * p9_client_flush - flush (cancel) a request
639  * @c: client state
640  * @oldreq: request to cancel
641  *
642  * This sents a flush for a particular request and links
643  * the flush request to the original request.  The current
644  * code only supports a single flush request although the protocol
645  * allows for multiple flush requests to be sent for a single request.
646  *
647  */
648 
649 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
650 {
651 	struct p9_req_t *req;
652 	s16 oldtag;
653 	int err;
654 
655 	err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
656 	if (err)
657 		return err;
658 
659 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
660 
661 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
662 	if (IS_ERR(req))
663 		return PTR_ERR(req);
664 
665 	/* if we haven't received a response for oldreq,
666 	 * remove it from the list
667 	 */
668 	if (oldreq->status == REQ_STATUS_SENT) {
669 		if (c->trans_mod->cancelled)
670 			c->trans_mod->cancelled(c, oldreq);
671 	}
672 
673 	p9_tag_remove(c, req);
674 	return 0;
675 }
676 
677 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
678 					      int8_t type, int req_size,
679 					      const char *fmt, va_list ap)
680 {
681 	int err;
682 	struct p9_req_t *req;
683 
684 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
685 
686 	/* we allow for any status other than disconnected */
687 	if (c->status == Disconnected)
688 		return ERR_PTR(-EIO);
689 
690 	/* if status is begin_disconnected we allow only clunk request */
691 	if (c->status == BeginDisconnect && type != P9_TCLUNK)
692 		return ERR_PTR(-EIO);
693 
694 	req = p9_tag_alloc(c, type, req_size);
695 	if (IS_ERR(req))
696 		return req;
697 
698 	/* marshall the data */
699 	p9pdu_prepare(&req->tc, req->tc.tag, type);
700 	err = p9pdu_vwritef(&req->tc, c->proto_version, fmt, ap);
701 	if (err)
702 		goto reterr;
703 	p9pdu_finalize(c, &req->tc);
704 	trace_9p_client_req(c, type, req->tc.tag);
705 	return req;
706 reterr:
707 	p9_tag_remove(c, req);
708 	/* We have to put also the 2nd reference as it won't be used */
709 	p9_req_put(c, req);
710 	return ERR_PTR(err);
711 }
712 
713 /**
714  * p9_client_rpc - issue a request and wait for a response
715  * @c: client session
716  * @type: type of request
717  * @fmt: protocol format string (see protocol.c)
718  *
719  * Returns request structure (which client must free using p9_tag_remove)
720  */
721 
722 static struct p9_req_t *
723 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
724 {
725 	va_list ap;
726 	int sigpending, err;
727 	unsigned long flags;
728 	struct p9_req_t *req;
729 
730 	va_start(ap, fmt);
731 	req = p9_client_prepare_req(c, type, c->msize, fmt, ap);
732 	va_end(ap);
733 	if (IS_ERR(req))
734 		return req;
735 
736 	if (signal_pending(current)) {
737 		sigpending = 1;
738 		clear_thread_flag(TIF_SIGPENDING);
739 	} else {
740 		sigpending = 0;
741 	}
742 
743 	err = c->trans_mod->request(c, req);
744 	if (err < 0) {
745 		/* write won't happen */
746 		p9_req_put(c, req);
747 		if (err != -ERESTARTSYS && err != -EFAULT)
748 			c->status = Disconnected;
749 		goto recalc_sigpending;
750 	}
751 again:
752 	/* Wait for the response */
753 	err = wait_event_killable(req->wq, req->status >= REQ_STATUS_RCVD);
754 
755 	/* Make sure our req is coherent with regard to updates in other
756 	 * threads - echoes to wmb() in the callback
757 	 */
758 	smp_rmb();
759 
760 	if (err == -ERESTARTSYS && c->status == Connected &&
761 	    type == P9_TFLUSH) {
762 		sigpending = 1;
763 		clear_thread_flag(TIF_SIGPENDING);
764 		goto again;
765 	}
766 
767 	if (req->status == REQ_STATUS_ERROR) {
768 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
769 		err = req->t_err;
770 	}
771 	if (err == -ERESTARTSYS && c->status == Connected) {
772 		p9_debug(P9_DEBUG_MUX, "flushing\n");
773 		sigpending = 1;
774 		clear_thread_flag(TIF_SIGPENDING);
775 
776 		if (c->trans_mod->cancel(c, req))
777 			p9_client_flush(c, req);
778 
779 		/* if we received the response anyway, don't signal error */
780 		if (req->status == REQ_STATUS_RCVD)
781 			err = 0;
782 	}
783 recalc_sigpending:
784 	if (sigpending) {
785 		spin_lock_irqsave(&current->sighand->siglock, flags);
786 		recalc_sigpending();
787 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
788 	}
789 	if (err < 0)
790 		goto reterr;
791 
792 	err = p9_check_errors(c, req);
793 	trace_9p_client_res(c, type, req->rc.tag, err);
794 	if (!err)
795 		return req;
796 reterr:
797 	p9_tag_remove(c, req);
798 	return ERR_PTR(safe_errno(err));
799 }
800 
801 /**
802  * p9_client_zc_rpc - issue a request and wait for a response
803  * @c: client session
804  * @type: type of request
805  * @uidata: destination for zero copy read
806  * @uodata: source for zero copy write
807  * @inlen: read buffer size
808  * @olen: write buffer size
809  * @in_hdrlen: reader header size, This is the size of response protocol data
810  * @fmt: protocol format string (see protocol.c)
811  *
812  * Returns request structure (which client must free using p9_tag_remove)
813  */
814 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
815 					 struct iov_iter *uidata,
816 					 struct iov_iter *uodata,
817 					 int inlen, int olen, int in_hdrlen,
818 					 const char *fmt, ...)
819 {
820 	va_list ap;
821 	int sigpending, err;
822 	unsigned long flags;
823 	struct p9_req_t *req;
824 
825 	va_start(ap, fmt);
826 	/* We allocate a inline protocol data of only 4k bytes.
827 	 * The actual content is passed in zero-copy fashion.
828 	 */
829 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, fmt, ap);
830 	va_end(ap);
831 	if (IS_ERR(req))
832 		return req;
833 
834 	if (signal_pending(current)) {
835 		sigpending = 1;
836 		clear_thread_flag(TIF_SIGPENDING);
837 	} else {
838 		sigpending = 0;
839 	}
840 
841 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
842 				       inlen, olen, in_hdrlen);
843 	if (err < 0) {
844 		if (err == -EIO)
845 			c->status = Disconnected;
846 		if (err != -ERESTARTSYS)
847 			goto recalc_sigpending;
848 	}
849 	if (req->status == REQ_STATUS_ERROR) {
850 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
851 		err = req->t_err;
852 	}
853 	if (err == -ERESTARTSYS && c->status == Connected) {
854 		p9_debug(P9_DEBUG_MUX, "flushing\n");
855 		sigpending = 1;
856 		clear_thread_flag(TIF_SIGPENDING);
857 
858 		if (c->trans_mod->cancel(c, req))
859 			p9_client_flush(c, req);
860 
861 		/* if we received the response anyway, don't signal error */
862 		if (req->status == REQ_STATUS_RCVD)
863 			err = 0;
864 	}
865 recalc_sigpending:
866 	if (sigpending) {
867 		spin_lock_irqsave(&current->sighand->siglock, flags);
868 		recalc_sigpending();
869 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
870 	}
871 	if (err < 0)
872 		goto reterr;
873 
874 	err = p9_check_zc_errors(c, req, uidata, in_hdrlen);
875 	trace_9p_client_res(c, type, req->rc.tag, err);
876 	if (!err)
877 		return req;
878 reterr:
879 	p9_tag_remove(c, req);
880 	return ERR_PTR(safe_errno(err));
881 }
882 
883 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
884 {
885 	int ret;
886 	struct p9_fid *fid;
887 
888 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
889 	fid = kmalloc(sizeof(*fid), GFP_KERNEL);
890 	if (!fid)
891 		return NULL;
892 
893 	memset(&fid->qid, 0, sizeof(fid->qid));
894 	fid->mode = -1;
895 	fid->uid = current_fsuid();
896 	fid->clnt = clnt;
897 	fid->rdir = NULL;
898 	fid->fid = 0;
899 	refcount_set(&fid->count, 1);
900 
901 	idr_preload(GFP_KERNEL);
902 	spin_lock_irq(&clnt->lock);
903 	ret = idr_alloc_u32(&clnt->fids, fid, &fid->fid, P9_NOFID - 1,
904 			    GFP_NOWAIT);
905 	spin_unlock_irq(&clnt->lock);
906 	idr_preload_end();
907 	if (!ret) {
908 		trace_9p_fid_ref(fid, P9_FID_REF_CREATE);
909 		return fid;
910 	}
911 
912 	kfree(fid);
913 	return NULL;
914 }
915 
916 static void p9_fid_destroy(struct p9_fid *fid)
917 {
918 	struct p9_client *clnt;
919 	unsigned long flags;
920 
921 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
922 	trace_9p_fid_ref(fid, P9_FID_REF_DESTROY);
923 	clnt = fid->clnt;
924 	spin_lock_irqsave(&clnt->lock, flags);
925 	idr_remove(&clnt->fids, fid->fid);
926 	spin_unlock_irqrestore(&clnt->lock, flags);
927 	kfree(fid->rdir);
928 	kfree(fid);
929 }
930 
931 /* We also need to export tracepoint symbols for tracepoint_enabled() */
932 EXPORT_TRACEPOINT_SYMBOL(9p_fid_ref);
933 
934 void do_trace_9p_fid_get(struct p9_fid *fid)
935 {
936 	trace_9p_fid_ref(fid, P9_FID_REF_GET);
937 }
938 EXPORT_SYMBOL(do_trace_9p_fid_get);
939 
940 void do_trace_9p_fid_put(struct p9_fid *fid)
941 {
942 	trace_9p_fid_ref(fid, P9_FID_REF_PUT);
943 }
944 EXPORT_SYMBOL(do_trace_9p_fid_put);
945 
946 static int p9_client_version(struct p9_client *c)
947 {
948 	int err = 0;
949 	struct p9_req_t *req;
950 	char *version = NULL;
951 	int msize;
952 
953 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
954 		 c->msize, c->proto_version);
955 
956 	switch (c->proto_version) {
957 	case p9_proto_2000L:
958 		req = p9_client_rpc(c, P9_TVERSION, "ds",
959 				    c->msize, "9P2000.L");
960 		break;
961 	case p9_proto_2000u:
962 		req = p9_client_rpc(c, P9_TVERSION, "ds",
963 				    c->msize, "9P2000.u");
964 		break;
965 	case p9_proto_legacy:
966 		req = p9_client_rpc(c, P9_TVERSION, "ds",
967 				    c->msize, "9P2000");
968 		break;
969 	default:
970 		return -EINVAL;
971 	}
972 
973 	if (IS_ERR(req))
974 		return PTR_ERR(req);
975 
976 	err = p9pdu_readf(&req->rc, c->proto_version, "ds", &msize, &version);
977 	if (err) {
978 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
979 		trace_9p_protocol_dump(c, &req->rc);
980 		goto error;
981 	}
982 
983 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
984 	if (!strncmp(version, "9P2000.L", 8)) {
985 		c->proto_version = p9_proto_2000L;
986 	} else if (!strncmp(version, "9P2000.u", 8)) {
987 		c->proto_version = p9_proto_2000u;
988 	} else if (!strncmp(version, "9P2000", 6)) {
989 		c->proto_version = p9_proto_legacy;
990 	} else {
991 		p9_debug(P9_DEBUG_ERROR,
992 			 "server returned an unknown version: %s\n", version);
993 		err = -EREMOTEIO;
994 		goto error;
995 	}
996 
997 	if (msize < 4096) {
998 		p9_debug(P9_DEBUG_ERROR,
999 			 "server returned a msize < 4096: %d\n", msize);
1000 		err = -EREMOTEIO;
1001 		goto error;
1002 	}
1003 	if (msize < c->msize)
1004 		c->msize = msize;
1005 
1006 error:
1007 	kfree(version);
1008 	p9_tag_remove(c, req);
1009 
1010 	return err;
1011 }
1012 
1013 struct p9_client *p9_client_create(const char *dev_name, char *options)
1014 {
1015 	int err;
1016 	struct p9_client *clnt;
1017 	char *client_id;
1018 
1019 	err = 0;
1020 	clnt = kmalloc(sizeof(*clnt), GFP_KERNEL);
1021 	if (!clnt)
1022 		return ERR_PTR(-ENOMEM);
1023 
1024 	clnt->trans_mod = NULL;
1025 	clnt->trans = NULL;
1026 	clnt->fcall_cache = NULL;
1027 
1028 	client_id = utsname()->nodename;
1029 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
1030 
1031 	spin_lock_init(&clnt->lock);
1032 	idr_init(&clnt->fids);
1033 	idr_init(&clnt->reqs);
1034 
1035 	err = parse_opts(options, clnt);
1036 	if (err < 0)
1037 		goto free_client;
1038 
1039 	if (!clnt->trans_mod)
1040 		clnt->trans_mod = v9fs_get_default_trans();
1041 
1042 	if (!clnt->trans_mod) {
1043 		err = -EPROTONOSUPPORT;
1044 		p9_debug(P9_DEBUG_ERROR,
1045 			 "No transport defined or default transport\n");
1046 		goto free_client;
1047 	}
1048 
1049 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
1050 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
1051 
1052 	err = clnt->trans_mod->create(clnt, dev_name, options);
1053 	if (err)
1054 		goto put_trans;
1055 
1056 	if (clnt->msize > clnt->trans_mod->maxsize) {
1057 		clnt->msize = clnt->trans_mod->maxsize;
1058 		pr_info("Limiting 'msize' to %d as this is the maximum "
1059 			"supported by transport %s\n",
1060 			clnt->msize, clnt->trans_mod->name
1061 		);
1062 	}
1063 
1064 	if (clnt->msize < 4096) {
1065 		p9_debug(P9_DEBUG_ERROR,
1066 			 "Please specify a msize of at least 4k\n");
1067 		err = -EINVAL;
1068 		goto close_trans;
1069 	}
1070 
1071 	err = p9_client_version(clnt);
1072 	if (err)
1073 		goto close_trans;
1074 
1075 	/* P9_HDRSZ + 4 is the smallest packet header we can have that is
1076 	 * followed by data accessed from userspace by read
1077 	 */
1078 	clnt->fcall_cache =
1079 		kmem_cache_create_usercopy("9p-fcall-cache", clnt->msize,
1080 					   0, 0, P9_HDRSZ + 4,
1081 					   clnt->msize - (P9_HDRSZ + 4),
1082 					   NULL);
1083 
1084 	return clnt;
1085 
1086 close_trans:
1087 	clnt->trans_mod->close(clnt);
1088 put_trans:
1089 	v9fs_put_trans(clnt->trans_mod);
1090 free_client:
1091 	kfree(clnt);
1092 	return ERR_PTR(err);
1093 }
1094 EXPORT_SYMBOL(p9_client_create);
1095 
1096 void p9_client_destroy(struct p9_client *clnt)
1097 {
1098 	struct p9_fid *fid;
1099 	int id;
1100 
1101 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1102 
1103 	if (clnt->trans_mod)
1104 		clnt->trans_mod->close(clnt);
1105 
1106 	v9fs_put_trans(clnt->trans_mod);
1107 
1108 	idr_for_each_entry(&clnt->fids, fid, id) {
1109 		pr_info("Found fid %d not clunked\n", fid->fid);
1110 		p9_fid_destroy(fid);
1111 	}
1112 
1113 	p9_tag_cleanup(clnt);
1114 
1115 	kmem_cache_destroy(clnt->fcall_cache);
1116 	kfree(clnt);
1117 }
1118 EXPORT_SYMBOL(p9_client_destroy);
1119 
1120 void p9_client_disconnect(struct p9_client *clnt)
1121 {
1122 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1123 	clnt->status = Disconnected;
1124 }
1125 EXPORT_SYMBOL(p9_client_disconnect);
1126 
1127 void p9_client_begin_disconnect(struct p9_client *clnt)
1128 {
1129 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1130 	clnt->status = BeginDisconnect;
1131 }
1132 EXPORT_SYMBOL(p9_client_begin_disconnect);
1133 
1134 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1135 				const char *uname, kuid_t n_uname,
1136 				const char *aname)
1137 {
1138 	int err = 0;
1139 	struct p9_req_t *req;
1140 	struct p9_fid *fid;
1141 	struct p9_qid qid;
1142 
1143 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1144 		 afid ? afid->fid : -1, uname, aname);
1145 	fid = p9_fid_create(clnt);
1146 	if (!fid) {
1147 		err = -ENOMEM;
1148 		goto error;
1149 	}
1150 	fid->uid = n_uname;
1151 
1152 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
1153 			    afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
1154 	if (IS_ERR(req)) {
1155 		err = PTR_ERR(req);
1156 		goto error;
1157 	}
1158 
1159 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", &qid);
1160 	if (err) {
1161 		trace_9p_protocol_dump(clnt, &req->rc);
1162 		p9_tag_remove(clnt, req);
1163 		goto error;
1164 	}
1165 
1166 	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
1167 		 qid.type, qid.path, qid.version);
1168 
1169 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1170 
1171 	p9_tag_remove(clnt, req);
1172 	return fid;
1173 
1174 error:
1175 	if (fid)
1176 		p9_fid_destroy(fid);
1177 	return ERR_PTR(err);
1178 }
1179 EXPORT_SYMBOL(p9_client_attach);
1180 
1181 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
1182 			      const unsigned char * const *wnames, int clone)
1183 {
1184 	int err;
1185 	struct p9_client *clnt;
1186 	struct p9_fid *fid;
1187 	struct p9_qid *wqids;
1188 	struct p9_req_t *req;
1189 	u16 nwqids, count;
1190 
1191 	err = 0;
1192 	wqids = NULL;
1193 	clnt = oldfid->clnt;
1194 	if (clone) {
1195 		fid = p9_fid_create(clnt);
1196 		if (!fid) {
1197 			err = -ENOMEM;
1198 			goto error;
1199 		}
1200 
1201 		fid->uid = oldfid->uid;
1202 	} else {
1203 		fid = oldfid;
1204 	}
1205 
1206 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1207 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1208 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1209 			    nwname, wnames);
1210 	if (IS_ERR(req)) {
1211 		err = PTR_ERR(req);
1212 		goto error;
1213 	}
1214 
1215 	err = p9pdu_readf(&req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1216 	if (err) {
1217 		trace_9p_protocol_dump(clnt, &req->rc);
1218 		p9_tag_remove(clnt, req);
1219 		goto clunk_fid;
1220 	}
1221 	p9_tag_remove(clnt, req);
1222 
1223 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1224 
1225 	if (nwqids != nwname) {
1226 		err = -ENOENT;
1227 		goto clunk_fid;
1228 	}
1229 
1230 	for (count = 0; count < nwqids; count++)
1231 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1232 			 count, wqids[count].type,
1233 			 wqids[count].path,
1234 			 wqids[count].version);
1235 
1236 	if (nwname)
1237 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1238 	else
1239 		memmove(&fid->qid, &oldfid->qid, sizeof(struct p9_qid));
1240 
1241 	kfree(wqids);
1242 	return fid;
1243 
1244 clunk_fid:
1245 	kfree(wqids);
1246 	p9_fid_put(fid);
1247 	fid = NULL;
1248 
1249 error:
1250 	if (fid && fid != oldfid)
1251 		p9_fid_destroy(fid);
1252 
1253 	return ERR_PTR(err);
1254 }
1255 EXPORT_SYMBOL(p9_client_walk);
1256 
1257 int p9_client_open(struct p9_fid *fid, int mode)
1258 {
1259 	int err;
1260 	struct p9_client *clnt;
1261 	struct p9_req_t *req;
1262 	struct p9_qid qid;
1263 	int iounit;
1264 
1265 	clnt = fid->clnt;
1266 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1267 		 p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1268 	err = 0;
1269 
1270 	if (fid->mode != -1)
1271 		return -EINVAL;
1272 
1273 	if (p9_is_proto_dotl(clnt))
1274 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode);
1275 	else
1276 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
1277 	if (IS_ERR(req)) {
1278 		err = PTR_ERR(req);
1279 		goto error;
1280 	}
1281 
1282 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1283 	if (err) {
1284 		trace_9p_protocol_dump(clnt, &req->rc);
1285 		goto free_and_error;
1286 	}
1287 
1288 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1289 		 p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1290 		 qid.path, qid.version, iounit);
1291 
1292 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1293 	fid->mode = mode;
1294 	fid->iounit = iounit;
1295 
1296 free_and_error:
1297 	p9_tag_remove(clnt, req);
1298 error:
1299 	return err;
1300 }
1301 EXPORT_SYMBOL(p9_client_open);
1302 
1303 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags,
1304 			  u32 mode, kgid_t gid, struct p9_qid *qid)
1305 {
1306 	int err = 0;
1307 	struct p9_client *clnt;
1308 	struct p9_req_t *req;
1309 	int iounit;
1310 
1311 	p9_debug(P9_DEBUG_9P,
1312 		 ">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1313 		 ofid->fid, name, flags, mode,
1314 		 from_kgid(&init_user_ns, gid));
1315 	clnt = ofid->clnt;
1316 
1317 	if (ofid->mode != -1)
1318 		return -EINVAL;
1319 
1320 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1321 			    mode, gid);
1322 	if (IS_ERR(req)) {
1323 		err = PTR_ERR(req);
1324 		goto error;
1325 	}
1326 
1327 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", qid, &iounit);
1328 	if (err) {
1329 		trace_9p_protocol_dump(clnt, &req->rc);
1330 		goto free_and_error;
1331 	}
1332 
1333 	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1334 		 qid->type, qid->path, qid->version, iounit);
1335 
1336 	memmove(&ofid->qid, qid, sizeof(struct p9_qid));
1337 	ofid->mode = mode;
1338 	ofid->iounit = iounit;
1339 
1340 free_and_error:
1341 	p9_tag_remove(clnt, req);
1342 error:
1343 	return err;
1344 }
1345 EXPORT_SYMBOL(p9_client_create_dotl);
1346 
1347 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1348 		     char *extension)
1349 {
1350 	int err;
1351 	struct p9_client *clnt;
1352 	struct p9_req_t *req;
1353 	struct p9_qid qid;
1354 	int iounit;
1355 
1356 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1357 		 fid->fid, name, perm, mode);
1358 	err = 0;
1359 	clnt = fid->clnt;
1360 
1361 	if (fid->mode != -1)
1362 		return -EINVAL;
1363 
1364 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1365 			    mode, extension);
1366 	if (IS_ERR(req)) {
1367 		err = PTR_ERR(req);
1368 		goto error;
1369 	}
1370 
1371 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1372 	if (err) {
1373 		trace_9p_protocol_dump(clnt, &req->rc);
1374 		goto free_and_error;
1375 	}
1376 
1377 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1378 		 qid.type, qid.path, qid.version, iounit);
1379 
1380 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1381 	fid->mode = mode;
1382 	fid->iounit = iounit;
1383 
1384 free_and_error:
1385 	p9_tag_remove(clnt, req);
1386 error:
1387 	return err;
1388 }
1389 EXPORT_SYMBOL(p9_client_fcreate);
1390 
1391 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1392 		      const char *symtgt, kgid_t gid, struct p9_qid *qid)
1393 {
1394 	int err = 0;
1395 	struct p9_client *clnt;
1396 	struct p9_req_t *req;
1397 
1398 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1399 		 dfid->fid, name, symtgt);
1400 	clnt = dfid->clnt;
1401 
1402 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1403 			    gid);
1404 	if (IS_ERR(req)) {
1405 		err = PTR_ERR(req);
1406 		goto error;
1407 	}
1408 
1409 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
1410 	if (err) {
1411 		trace_9p_protocol_dump(clnt, &req->rc);
1412 		goto free_and_error;
1413 	}
1414 
1415 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1416 		 qid->type, qid->path, qid->version);
1417 
1418 free_and_error:
1419 	p9_tag_remove(clnt, req);
1420 error:
1421 	return err;
1422 }
1423 EXPORT_SYMBOL(p9_client_symlink);
1424 
1425 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1426 {
1427 	struct p9_client *clnt;
1428 	struct p9_req_t *req;
1429 
1430 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1431 		 dfid->fid, oldfid->fid, newname);
1432 	clnt = dfid->clnt;
1433 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1434 			    newname);
1435 	if (IS_ERR(req))
1436 		return PTR_ERR(req);
1437 
1438 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1439 	p9_tag_remove(clnt, req);
1440 	return 0;
1441 }
1442 EXPORT_SYMBOL(p9_client_link);
1443 
1444 int p9_client_fsync(struct p9_fid *fid, int datasync)
1445 {
1446 	int err;
1447 	struct p9_client *clnt;
1448 	struct p9_req_t *req;
1449 
1450 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1451 		 fid->fid, datasync);
1452 	err = 0;
1453 	clnt = fid->clnt;
1454 
1455 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1456 	if (IS_ERR(req)) {
1457 		err = PTR_ERR(req);
1458 		goto error;
1459 	}
1460 
1461 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1462 
1463 	p9_tag_remove(clnt, req);
1464 
1465 error:
1466 	return err;
1467 }
1468 EXPORT_SYMBOL(p9_client_fsync);
1469 
1470 int p9_client_clunk(struct p9_fid *fid)
1471 {
1472 	int err;
1473 	struct p9_client *clnt;
1474 	struct p9_req_t *req;
1475 	int retries = 0;
1476 
1477 again:
1478 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n",
1479 		 fid->fid, retries);
1480 	err = 0;
1481 	clnt = fid->clnt;
1482 
1483 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1484 	if (IS_ERR(req)) {
1485 		err = PTR_ERR(req);
1486 		goto error;
1487 	}
1488 
1489 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1490 
1491 	p9_tag_remove(clnt, req);
1492 error:
1493 	/* Fid is not valid even after a failed clunk
1494 	 * If interrupted, retry once then give up and
1495 	 * leak fid until umount.
1496 	 */
1497 	if (err == -ERESTARTSYS) {
1498 		if (retries++ == 0)
1499 			goto again;
1500 	} else {
1501 		p9_fid_destroy(fid);
1502 	}
1503 	return err;
1504 }
1505 EXPORT_SYMBOL(p9_client_clunk);
1506 
1507 int p9_client_remove(struct p9_fid *fid)
1508 {
1509 	int err;
1510 	struct p9_client *clnt;
1511 	struct p9_req_t *req;
1512 
1513 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1514 	err = 0;
1515 	clnt = fid->clnt;
1516 
1517 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1518 	if (IS_ERR(req)) {
1519 		err = PTR_ERR(req);
1520 		goto error;
1521 	}
1522 
1523 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1524 
1525 	p9_tag_remove(clnt, req);
1526 error:
1527 	if (err == -ERESTARTSYS)
1528 		p9_fid_put(fid);
1529 	else
1530 		p9_fid_destroy(fid);
1531 	return err;
1532 }
1533 EXPORT_SYMBOL(p9_client_remove);
1534 
1535 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1536 {
1537 	int err = 0;
1538 	struct p9_req_t *req;
1539 	struct p9_client *clnt;
1540 
1541 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1542 		 dfid->fid, name, flags);
1543 
1544 	clnt = dfid->clnt;
1545 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1546 	if (IS_ERR(req)) {
1547 		err = PTR_ERR(req);
1548 		goto error;
1549 	}
1550 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1551 
1552 	p9_tag_remove(clnt, req);
1553 error:
1554 	return err;
1555 }
1556 EXPORT_SYMBOL(p9_client_unlinkat);
1557 
1558 int
1559 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1560 {
1561 	int total = 0;
1562 	*err = 0;
1563 
1564 	while (iov_iter_count(to)) {
1565 		int count;
1566 
1567 		count = p9_client_read_once(fid, offset, to, err);
1568 		if (!count || *err)
1569 			break;
1570 		offset += count;
1571 		total += count;
1572 	}
1573 	return total;
1574 }
1575 EXPORT_SYMBOL(p9_client_read);
1576 
1577 int
1578 p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
1579 		    int *err)
1580 {
1581 	struct p9_client *clnt = fid->clnt;
1582 	struct p9_req_t *req;
1583 	int count = iov_iter_count(to);
1584 	int rsize, non_zc = 0;
1585 	char *dataptr;
1586 
1587 	*err = 0;
1588 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %zu\n",
1589 		 fid->fid, offset, iov_iter_count(to));
1590 
1591 	rsize = fid->iounit;
1592 	if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1593 		rsize = clnt->msize - P9_IOHDRSZ;
1594 
1595 	if (count < rsize)
1596 		rsize = count;
1597 
1598 	/* Don't bother zerocopy for small IO (< 1024) */
1599 	if (clnt->trans_mod->zc_request && rsize > 1024) {
1600 		/* response header len is 11
1601 		 * PDU Header(7) + IO Size (4)
1602 		 */
1603 		req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1604 				       0, 11, "dqd", fid->fid,
1605 				       offset, rsize);
1606 	} else {
1607 		non_zc = 1;
1608 		req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1609 				    rsize);
1610 	}
1611 	if (IS_ERR(req)) {
1612 		*err = PTR_ERR(req);
1613 		return 0;
1614 	}
1615 
1616 	*err = p9pdu_readf(&req->rc, clnt->proto_version,
1617 			   "D", &count, &dataptr);
1618 	if (*err) {
1619 		trace_9p_protocol_dump(clnt, &req->rc);
1620 		p9_tag_remove(clnt, req);
1621 		return 0;
1622 	}
1623 	if (rsize < count) {
1624 		pr_err("bogus RREAD count (%d > %d)\n", count, rsize);
1625 		count = rsize;
1626 	}
1627 
1628 	p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1629 
1630 	if (non_zc) {
1631 		int n = copy_to_iter(dataptr, count, to);
1632 
1633 		if (n != count) {
1634 			*err = -EFAULT;
1635 			p9_tag_remove(clnt, req);
1636 			return n;
1637 		}
1638 	} else {
1639 		iov_iter_advance(to, count);
1640 	}
1641 	p9_tag_remove(clnt, req);
1642 	return count;
1643 }
1644 EXPORT_SYMBOL(p9_client_read_once);
1645 
1646 int
1647 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1648 {
1649 	struct p9_client *clnt = fid->clnt;
1650 	struct p9_req_t *req;
1651 	int total = 0;
1652 	*err = 0;
1653 
1654 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n",
1655 		 fid->fid, offset, iov_iter_count(from));
1656 
1657 	while (iov_iter_count(from)) {
1658 		int count = iov_iter_count(from);
1659 		int rsize = fid->iounit;
1660 
1661 		if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1662 			rsize = clnt->msize - P9_IOHDRSZ;
1663 
1664 		if (count < rsize)
1665 			rsize = count;
1666 
1667 		/* Don't bother zerocopy for small IO (< 1024) */
1668 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1669 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1670 					       rsize, P9_ZC_HDR_SZ, "dqd",
1671 					       fid->fid, offset, rsize);
1672 		} else {
1673 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1674 					    offset, rsize, from);
1675 		}
1676 		if (IS_ERR(req)) {
1677 			*err = PTR_ERR(req);
1678 			break;
1679 		}
1680 
1681 		*err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &count);
1682 		if (*err) {
1683 			trace_9p_protocol_dump(clnt, &req->rc);
1684 			p9_tag_remove(clnt, req);
1685 			break;
1686 		}
1687 		if (rsize < count) {
1688 			pr_err("bogus RWRITE count (%d > %d)\n", count, rsize);
1689 			count = rsize;
1690 		}
1691 
1692 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1693 
1694 		p9_tag_remove(clnt, req);
1695 		iov_iter_advance(from, count);
1696 		total += count;
1697 		offset += count;
1698 	}
1699 	return total;
1700 }
1701 EXPORT_SYMBOL(p9_client_write);
1702 
1703 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1704 {
1705 	int err;
1706 	struct p9_client *clnt;
1707 	struct p9_wstat *ret;
1708 	struct p9_req_t *req;
1709 	u16 ignored;
1710 
1711 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1712 
1713 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1714 	if (!ret)
1715 		return ERR_PTR(-ENOMEM);
1716 
1717 	err = 0;
1718 	clnt = fid->clnt;
1719 
1720 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1721 	if (IS_ERR(req)) {
1722 		err = PTR_ERR(req);
1723 		goto error;
1724 	}
1725 
1726 	err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
1727 	if (err) {
1728 		trace_9p_protocol_dump(clnt, &req->rc);
1729 		p9_tag_remove(clnt, req);
1730 		goto error;
1731 	}
1732 
1733 	p9_debug(P9_DEBUG_9P,
1734 		 "<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1735 		 "<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1736 		 "<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1737 		 "<<<    uid=%d gid=%d n_muid=%d\n",
1738 		 ret->size, ret->type, ret->dev, ret->qid.type, ret->qid.path,
1739 		 ret->qid.version, ret->mode,
1740 		 ret->atime, ret->mtime, ret->length,
1741 		 ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1742 		 from_kuid(&init_user_ns, ret->n_uid),
1743 		 from_kgid(&init_user_ns, ret->n_gid),
1744 		 from_kuid(&init_user_ns, ret->n_muid));
1745 
1746 	p9_tag_remove(clnt, req);
1747 	return ret;
1748 
1749 error:
1750 	kfree(ret);
1751 	return ERR_PTR(err);
1752 }
1753 EXPORT_SYMBOL(p9_client_stat);
1754 
1755 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1756 					    u64 request_mask)
1757 {
1758 	int err;
1759 	struct p9_client *clnt;
1760 	struct p9_stat_dotl *ret;
1761 	struct p9_req_t *req;
1762 
1763 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1764 		 fid->fid, request_mask);
1765 
1766 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1767 	if (!ret)
1768 		return ERR_PTR(-ENOMEM);
1769 
1770 	err = 0;
1771 	clnt = fid->clnt;
1772 
1773 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1774 	if (IS_ERR(req)) {
1775 		err = PTR_ERR(req);
1776 		goto error;
1777 	}
1778 
1779 	err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
1780 	if (err) {
1781 		trace_9p_protocol_dump(clnt, &req->rc);
1782 		p9_tag_remove(clnt, req);
1783 		goto error;
1784 	}
1785 
1786 	p9_debug(P9_DEBUG_9P, "<<< RGETATTR st_result_mask=%lld\n"
1787 		 "<<< qid=%x.%llx.%x\n"
1788 		 "<<< st_mode=%8.8x st_nlink=%llu\n"
1789 		 "<<< st_uid=%d st_gid=%d\n"
1790 		 "<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1791 		 "<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1792 		 "<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1793 		 "<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1794 		 "<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1795 		 "<<< st_gen=%lld st_data_version=%lld\n",
1796 		 ret->st_result_mask,
1797 		 ret->qid.type, ret->qid.path, ret->qid.version,
1798 		 ret->st_mode, ret->st_nlink,
1799 		 from_kuid(&init_user_ns, ret->st_uid),
1800 		 from_kgid(&init_user_ns, ret->st_gid),
1801 		 ret->st_rdev, ret->st_size, ret->st_blksize, ret->st_blocks,
1802 		 ret->st_atime_sec, ret->st_atime_nsec,
1803 		 ret->st_mtime_sec, ret->st_mtime_nsec,
1804 		 ret->st_ctime_sec, ret->st_ctime_nsec,
1805 		 ret->st_btime_sec, ret->st_btime_nsec,
1806 		 ret->st_gen, ret->st_data_version);
1807 
1808 	p9_tag_remove(clnt, req);
1809 	return ret;
1810 
1811 error:
1812 	kfree(ret);
1813 	return ERR_PTR(err);
1814 }
1815 EXPORT_SYMBOL(p9_client_getattr_dotl);
1816 
1817 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1818 {
1819 	int ret;
1820 
1821 	/* NOTE: size shouldn't include its own length */
1822 	/* size[2] type[2] dev[4] qid[13] */
1823 	/* mode[4] atime[4] mtime[4] length[8]*/
1824 	/* name[s] uid[s] gid[s] muid[s] */
1825 	ret = 2 + 4 + 13 + 4 + 4 + 4 + 8 + 2 + 2 + 2 + 2;
1826 
1827 	if (wst->name)
1828 		ret += strlen(wst->name);
1829 	if (wst->uid)
1830 		ret += strlen(wst->uid);
1831 	if (wst->gid)
1832 		ret += strlen(wst->gid);
1833 	if (wst->muid)
1834 		ret += strlen(wst->muid);
1835 
1836 	if (proto_version == p9_proto_2000u ||
1837 	    proto_version == p9_proto_2000L) {
1838 		/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1839 		ret += 2 + 4 + 4 + 4;
1840 		if (wst->extension)
1841 			ret += strlen(wst->extension);
1842 	}
1843 
1844 	return ret;
1845 }
1846 
1847 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1848 {
1849 	int err;
1850 	struct p9_req_t *req;
1851 	struct p9_client *clnt;
1852 
1853 	err = 0;
1854 	clnt = fid->clnt;
1855 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1856 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n",
1857 		 fid->fid);
1858 	p9_debug(P9_DEBUG_9P,
1859 		 "     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1860 		 "     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1861 		 "     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1862 		 "     uid=%d gid=%d n_muid=%d\n",
1863 		 wst->size, wst->type, wst->dev, wst->qid.type,
1864 		 wst->qid.path, wst->qid.version,
1865 		 wst->mode, wst->atime, wst->mtime, wst->length,
1866 		 wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1867 		 from_kuid(&init_user_ns, wst->n_uid),
1868 		 from_kgid(&init_user_ns, wst->n_gid),
1869 		 from_kuid(&init_user_ns, wst->n_muid));
1870 
1871 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS",
1872 			    fid->fid, wst->size + 2, wst);
1873 	if (IS_ERR(req)) {
1874 		err = PTR_ERR(req);
1875 		goto error;
1876 	}
1877 
1878 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1879 
1880 	p9_tag_remove(clnt, req);
1881 error:
1882 	return err;
1883 }
1884 EXPORT_SYMBOL(p9_client_wstat);
1885 
1886 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1887 {
1888 	int err;
1889 	struct p9_req_t *req;
1890 	struct p9_client *clnt;
1891 
1892 	err = 0;
1893 	clnt = fid->clnt;
1894 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1895 	p9_debug(P9_DEBUG_9P, "    valid=%x mode=%x uid=%d gid=%d size=%lld\n",
1896 		 p9attr->valid, p9attr->mode,
1897 		 from_kuid(&init_user_ns, p9attr->uid),
1898 		 from_kgid(&init_user_ns, p9attr->gid),
1899 		 p9attr->size);
1900 	p9_debug(P9_DEBUG_9P, "    atime_sec=%lld atime_nsec=%lld\n",
1901 		 p9attr->atime_sec, p9attr->atime_nsec);
1902 	p9_debug(P9_DEBUG_9P, "    mtime_sec=%lld mtime_nsec=%lld\n",
1903 		 p9attr->mtime_sec, p9attr->mtime_nsec);
1904 
1905 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1906 
1907 	if (IS_ERR(req)) {
1908 		err = PTR_ERR(req);
1909 		goto error;
1910 	}
1911 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1912 	p9_tag_remove(clnt, req);
1913 error:
1914 	return err;
1915 }
1916 EXPORT_SYMBOL(p9_client_setattr);
1917 
1918 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1919 {
1920 	int err;
1921 	struct p9_req_t *req;
1922 	struct p9_client *clnt;
1923 
1924 	err = 0;
1925 	clnt = fid->clnt;
1926 
1927 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1928 
1929 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1930 	if (IS_ERR(req)) {
1931 		err = PTR_ERR(req);
1932 		goto error;
1933 	}
1934 
1935 	err = p9pdu_readf(&req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1936 			  &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1937 			  &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1938 	if (err) {
1939 		trace_9p_protocol_dump(clnt, &req->rc);
1940 		p9_tag_remove(clnt, req);
1941 		goto error;
1942 	}
1943 
1944 	p9_debug(P9_DEBUG_9P,
1945 		 "<<< RSTATFS fid %d type 0x%x bsize %u blocks %llu bfree %llu bavail %llu files %llu ffree %llu fsid %llu namelen %u\n",
1946 		 fid->fid, sb->type, sb->bsize, sb->blocks, sb->bfree,
1947 		 sb->bavail, sb->files, sb->ffree, sb->fsid, sb->namelen);
1948 
1949 	p9_tag_remove(clnt, req);
1950 error:
1951 	return err;
1952 }
1953 EXPORT_SYMBOL(p9_client_statfs);
1954 
1955 int p9_client_rename(struct p9_fid *fid,
1956 		     struct p9_fid *newdirfid, const char *name)
1957 {
1958 	int err;
1959 	struct p9_req_t *req;
1960 	struct p9_client *clnt;
1961 
1962 	err = 0;
1963 	clnt = fid->clnt;
1964 
1965 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1966 		 fid->fid, newdirfid->fid, name);
1967 
1968 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1969 			    newdirfid->fid, name);
1970 	if (IS_ERR(req)) {
1971 		err = PTR_ERR(req);
1972 		goto error;
1973 	}
1974 
1975 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1976 
1977 	p9_tag_remove(clnt, req);
1978 error:
1979 	return err;
1980 }
1981 EXPORT_SYMBOL(p9_client_rename);
1982 
1983 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
1984 		       struct p9_fid *newdirfid, const char *new_name)
1985 {
1986 	int err;
1987 	struct p9_req_t *req;
1988 	struct p9_client *clnt;
1989 
1990 	err = 0;
1991 	clnt = olddirfid->clnt;
1992 
1993 	p9_debug(P9_DEBUG_9P,
1994 		 ">>> TRENAMEAT olddirfid %d old name %s newdirfid %d new name %s\n",
1995 		 olddirfid->fid, old_name, newdirfid->fid, new_name);
1996 
1997 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
1998 			    old_name, newdirfid->fid, new_name);
1999 	if (IS_ERR(req)) {
2000 		err = PTR_ERR(req);
2001 		goto error;
2002 	}
2003 
2004 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
2005 		 newdirfid->fid, new_name);
2006 
2007 	p9_tag_remove(clnt, req);
2008 error:
2009 	return err;
2010 }
2011 EXPORT_SYMBOL(p9_client_renameat);
2012 
2013 /* An xattrwalk without @attr_name gives the fid for the lisxattr namespace
2014  */
2015 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
2016 				   const char *attr_name, u64 *attr_size)
2017 {
2018 	int err;
2019 	struct p9_req_t *req;
2020 	struct p9_client *clnt;
2021 	struct p9_fid *attr_fid;
2022 
2023 	err = 0;
2024 	clnt = file_fid->clnt;
2025 	attr_fid = p9_fid_create(clnt);
2026 	if (!attr_fid) {
2027 		err = -ENOMEM;
2028 		goto error;
2029 	}
2030 	p9_debug(P9_DEBUG_9P,
2031 		 ">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
2032 		 file_fid->fid, attr_fid->fid, attr_name);
2033 
2034 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
2035 			    file_fid->fid, attr_fid->fid, attr_name);
2036 	if (IS_ERR(req)) {
2037 		err = PTR_ERR(req);
2038 		goto error;
2039 	}
2040 	err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
2041 	if (err) {
2042 		trace_9p_protocol_dump(clnt, &req->rc);
2043 		p9_tag_remove(clnt, req);
2044 		goto clunk_fid;
2045 	}
2046 	p9_tag_remove(clnt, req);
2047 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
2048 		 attr_fid->fid, *attr_size);
2049 	return attr_fid;
2050 clunk_fid:
2051 	p9_fid_put(attr_fid);
2052 	attr_fid = NULL;
2053 error:
2054 	if (attr_fid && attr_fid != file_fid)
2055 		p9_fid_destroy(attr_fid);
2056 
2057 	return ERR_PTR(err);
2058 }
2059 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
2060 
2061 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
2062 			  u64 attr_size, int flags)
2063 {
2064 	int err;
2065 	struct p9_req_t *req;
2066 	struct p9_client *clnt;
2067 
2068 	p9_debug(P9_DEBUG_9P,
2069 		 ">>> TXATTRCREATE fid %d name  %s size %llu flag %d\n",
2070 		 fid->fid, name, attr_size, flags);
2071 	err = 0;
2072 	clnt = fid->clnt;
2073 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
2074 			    fid->fid, name, attr_size, flags);
2075 	if (IS_ERR(req)) {
2076 		err = PTR_ERR(req);
2077 		goto error;
2078 	}
2079 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
2080 	p9_tag_remove(clnt, req);
2081 error:
2082 	return err;
2083 }
2084 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
2085 
2086 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
2087 {
2088 	int err, rsize, non_zc = 0;
2089 	struct p9_client *clnt;
2090 	struct p9_req_t *req;
2091 	char *dataptr;
2092 	struct kvec kv = {.iov_base = data, .iov_len = count};
2093 	struct iov_iter to;
2094 
2095 	iov_iter_kvec(&to, READ, &kv, 1, count);
2096 
2097 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
2098 		 fid->fid, offset, count);
2099 
2100 	err = 0;
2101 	clnt = fid->clnt;
2102 
2103 	rsize = fid->iounit;
2104 	if (!rsize || rsize > clnt->msize - P9_READDIRHDRSZ)
2105 		rsize = clnt->msize - P9_READDIRHDRSZ;
2106 
2107 	if (count < rsize)
2108 		rsize = count;
2109 
2110 	/* Don't bother zerocopy for small IO (< 1024) */
2111 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2112 		/* response header len is 11
2113 		 * PDU Header(7) + IO Size (4)
2114 		 */
2115 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2116 				       11, "dqd", fid->fid, offset, rsize);
2117 	} else {
2118 		non_zc = 1;
2119 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2120 				    offset, rsize);
2121 	}
2122 	if (IS_ERR(req)) {
2123 		err = PTR_ERR(req);
2124 		goto error;
2125 	}
2126 
2127 	err = p9pdu_readf(&req->rc, clnt->proto_version, "D", &count, &dataptr);
2128 	if (err) {
2129 		trace_9p_protocol_dump(clnt, &req->rc);
2130 		goto free_and_error;
2131 	}
2132 	if (rsize < count) {
2133 		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
2134 		count = rsize;
2135 	}
2136 
2137 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
2138 
2139 	if (non_zc)
2140 		memmove(data, dataptr, count);
2141 
2142 	p9_tag_remove(clnt, req);
2143 	return count;
2144 
2145 free_and_error:
2146 	p9_tag_remove(clnt, req);
2147 error:
2148 	return err;
2149 }
2150 EXPORT_SYMBOL(p9_client_readdir);
2151 
2152 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2153 			 dev_t rdev, kgid_t gid, struct p9_qid *qid)
2154 {
2155 	int err;
2156 	struct p9_client *clnt;
2157 	struct p9_req_t *req;
2158 
2159 	err = 0;
2160 	clnt = fid->clnt;
2161 	p9_debug(P9_DEBUG_9P,
2162 		 ">>> TMKNOD fid %d name %s mode %d major %d minor %d\n",
2163 		 fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2164 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2165 			    MAJOR(rdev), MINOR(rdev), gid);
2166 	if (IS_ERR(req))
2167 		return PTR_ERR(req);
2168 
2169 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2170 	if (err) {
2171 		trace_9p_protocol_dump(clnt, &req->rc);
2172 		goto error;
2173 	}
2174 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n",
2175 		 qid->type, qid->path, qid->version);
2176 
2177 error:
2178 	p9_tag_remove(clnt, req);
2179 	return err;
2180 }
2181 EXPORT_SYMBOL(p9_client_mknod_dotl);
2182 
2183 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2184 			 kgid_t gid, struct p9_qid *qid)
2185 {
2186 	int err;
2187 	struct p9_client *clnt;
2188 	struct p9_req_t *req;
2189 
2190 	err = 0;
2191 	clnt = fid->clnt;
2192 	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
2193 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
2194 	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg",
2195 			    fid->fid, name, mode, gid);
2196 	if (IS_ERR(req))
2197 		return PTR_ERR(req);
2198 
2199 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2200 	if (err) {
2201 		trace_9p_protocol_dump(clnt, &req->rc);
2202 		goto error;
2203 	}
2204 	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
2205 		 qid->path, qid->version);
2206 
2207 error:
2208 	p9_tag_remove(clnt, req);
2209 	return err;
2210 }
2211 EXPORT_SYMBOL(p9_client_mkdir_dotl);
2212 
2213 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
2214 {
2215 	int err;
2216 	struct p9_client *clnt;
2217 	struct p9_req_t *req;
2218 
2219 	err = 0;
2220 	clnt = fid->clnt;
2221 	p9_debug(P9_DEBUG_9P,
2222 		 ">>> TLOCK fid %d type %i flags %d start %lld length %lld proc_id %d client_id %s\n",
2223 		 fid->fid, flock->type, flock->flags, flock->start,
2224 		 flock->length, flock->proc_id, flock->client_id);
2225 
2226 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2227 			    flock->flags, flock->start, flock->length,
2228 			    flock->proc_id, flock->client_id);
2229 
2230 	if (IS_ERR(req))
2231 		return PTR_ERR(req);
2232 
2233 	err = p9pdu_readf(&req->rc, clnt->proto_version, "b", status);
2234 	if (err) {
2235 		trace_9p_protocol_dump(clnt, &req->rc);
2236 		goto error;
2237 	}
2238 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2239 error:
2240 	p9_tag_remove(clnt, req);
2241 	return err;
2242 }
2243 EXPORT_SYMBOL(p9_client_lock_dotl);
2244 
2245 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2246 {
2247 	int err;
2248 	struct p9_client *clnt;
2249 	struct p9_req_t *req;
2250 
2251 	err = 0;
2252 	clnt = fid->clnt;
2253 	p9_debug(P9_DEBUG_9P,
2254 		 ">>> TGETLOCK fid %d, type %i start %lld length %lld proc_id %d client_id %s\n",
2255 		 fid->fid, glock->type, glock->start, glock->length,
2256 		 glock->proc_id, glock->client_id);
2257 
2258 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,
2259 			    glock->type, glock->start, glock->length,
2260 			    glock->proc_id, glock->client_id);
2261 
2262 	if (IS_ERR(req))
2263 		return PTR_ERR(req);
2264 
2265 	err = p9pdu_readf(&req->rc, clnt->proto_version, "bqqds", &glock->type,
2266 			  &glock->start, &glock->length, &glock->proc_id,
2267 			  &glock->client_id);
2268 	if (err) {
2269 		trace_9p_protocol_dump(clnt, &req->rc);
2270 		goto error;
2271 	}
2272 	p9_debug(P9_DEBUG_9P,
2273 		 "<<< RGETLOCK type %i start %lld length %lld proc_id %d client_id %s\n",
2274 		 glock->type, glock->start, glock->length,
2275 		 glock->proc_id, glock->client_id);
2276 error:
2277 	p9_tag_remove(clnt, req);
2278 	return err;
2279 }
2280 EXPORT_SYMBOL(p9_client_getlock_dotl);
2281 
2282 int p9_client_readlink(struct p9_fid *fid, char **target)
2283 {
2284 	int err;
2285 	struct p9_client *clnt;
2286 	struct p9_req_t *req;
2287 
2288 	err = 0;
2289 	clnt = fid->clnt;
2290 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2291 
2292 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2293 	if (IS_ERR(req))
2294 		return PTR_ERR(req);
2295 
2296 	err = p9pdu_readf(&req->rc, clnt->proto_version, "s", target);
2297 	if (err) {
2298 		trace_9p_protocol_dump(clnt, &req->rc);
2299 		goto error;
2300 	}
2301 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2302 error:
2303 	p9_tag_remove(clnt, req);
2304 	return err;
2305 }
2306 EXPORT_SYMBOL(p9_client_readlink);
2307 
2308 int __init p9_client_init(void)
2309 {
2310 	p9_req_cache = KMEM_CACHE(p9_req_t, SLAB_TYPESAFE_BY_RCU);
2311 	return p9_req_cache ? 0 : -ENOMEM;
2312 }
2313 
2314 void __exit p9_client_exit(void)
2315 {
2316 	kmem_cache_destroy(p9_req_cache);
2317 }
2318