xref: /linux/net/9p/client.c (revision 249ebf3f65f8530beb2cbfb91bff1d83ba88d23c)
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 <linux/netfs.h>
22 #include <net/9p/9p.h>
23 #include <linux/parser.h>
24 #include <linux/seq_file.h>
25 #include <net/9p/client.h>
26 #include <net/9p/transport.h>
27 #include "protocol.h"
28 
29 #define CREATE_TRACE_POINTS
30 #include <trace/events/9p.h>
31 
32 /* DEFAULT MSIZE = 32 pages worth of payload + P9_HDRSZ +
33  * room for write (16 extra) or read (11 extra) operands.
34  */
35 
36 #define DEFAULT_MSIZE ((128 * 1024) + P9_IOHDRSZ)
37 
38 /* Client Option Parsing (code inspired by NFS code)
39  *  - a little lazy - parse all client options
40  */
41 
42 enum {
43 	Opt_msize,
44 	Opt_trans,
45 	Opt_legacy,
46 	Opt_version,
47 	Opt_err,
48 };
49 
50 static const match_table_t tokens = {
51 	{Opt_msize, "msize=%u"},
52 	{Opt_legacy, "noextend"},
53 	{Opt_trans, "trans=%s"},
54 	{Opt_version, "version=%s"},
55 	{Opt_err, NULL},
56 };
57 
58 inline int p9_is_proto_dotl(struct p9_client *clnt)
59 {
60 	return clnt->proto_version == p9_proto_2000L;
61 }
62 EXPORT_SYMBOL(p9_is_proto_dotl);
63 
64 inline int p9_is_proto_dotu(struct p9_client *clnt)
65 {
66 	return clnt->proto_version == p9_proto_2000u;
67 }
68 EXPORT_SYMBOL(p9_is_proto_dotu);
69 
70 int p9_show_client_options(struct seq_file *m, struct p9_client *clnt)
71 {
72 	if (clnt->msize != DEFAULT_MSIZE)
73 		seq_printf(m, ",msize=%u", clnt->msize);
74 	seq_printf(m, ",trans=%s", clnt->trans_mod->name);
75 
76 	switch (clnt->proto_version) {
77 	case p9_proto_legacy:
78 		seq_puts(m, ",noextend");
79 		break;
80 	case p9_proto_2000u:
81 		seq_puts(m, ",version=9p2000.u");
82 		break;
83 	case p9_proto_2000L:
84 		/* Default */
85 		break;
86 	}
87 
88 	if (clnt->trans_mod->show_options)
89 		return clnt->trans_mod->show_options(m, clnt);
90 	return 0;
91 }
92 EXPORT_SYMBOL(p9_show_client_options);
93 
94 /* Some error codes are taken directly from the server replies,
95  * make sure they are valid.
96  */
97 static int safe_errno(int err)
98 {
99 	if (err > 0 || err < -MAX_ERRNO) {
100 		p9_debug(P9_DEBUG_ERROR, "Invalid error code %d\n", err);
101 		return -EPROTO;
102 	}
103 	return err;
104 }
105 
106 /* Interpret mount option for protocol version */
107 static int get_protocol_version(char *s)
108 {
109 	int version = -EINVAL;
110 
111 	if (!strcmp(s, "9p2000")) {
112 		version = p9_proto_legacy;
113 		p9_debug(P9_DEBUG_9P, "Protocol version: Legacy\n");
114 	} else if (!strcmp(s, "9p2000.u")) {
115 		version = p9_proto_2000u;
116 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.u\n");
117 	} else if (!strcmp(s, "9p2000.L")) {
118 		version = p9_proto_2000L;
119 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.L\n");
120 	} else {
121 		pr_info("Unknown protocol version %s\n", s);
122 	}
123 
124 	return version;
125 }
126 
127 /**
128  * parse_opts - parse mount options into client structure
129  * @opts: options string passed from mount
130  * @clnt: existing v9fs client information
131  *
132  * Return 0 upon success, -ERRNO upon failure
133  */
134 
135 static int parse_opts(char *opts, struct p9_client *clnt)
136 {
137 	char *options, *tmp_options;
138 	char *p;
139 	substring_t args[MAX_OPT_ARGS];
140 	int option;
141 	char *s;
142 	int ret = 0;
143 
144 	clnt->proto_version = p9_proto_2000L;
145 	clnt->msize = DEFAULT_MSIZE;
146 
147 	if (!opts)
148 		return 0;
149 
150 	tmp_options = kstrdup(opts, GFP_KERNEL);
151 	if (!tmp_options)
152 		return -ENOMEM;
153 	options = tmp_options;
154 
155 	while ((p = strsep(&options, ",")) != NULL) {
156 		int token, r;
157 
158 		if (!*p)
159 			continue;
160 		token = match_token(p, tokens, args);
161 		switch (token) {
162 		case Opt_msize:
163 			r = match_int(&args[0], &option);
164 			if (r < 0) {
165 				p9_debug(P9_DEBUG_ERROR,
166 					 "integer field, but no integer?\n");
167 				ret = r;
168 				continue;
169 			}
170 			if (option < 4096) {
171 				p9_debug(P9_DEBUG_ERROR,
172 					 "msize should be at least 4k\n");
173 				ret = -EINVAL;
174 				continue;
175 			}
176 			clnt->msize = option;
177 			break;
178 		case Opt_trans:
179 			s = match_strdup(&args[0]);
180 			if (!s) {
181 				ret = -ENOMEM;
182 				p9_debug(P9_DEBUG_ERROR,
183 					 "problem allocating copy of trans arg\n");
184 				goto free_and_return;
185 			}
186 
187 			v9fs_put_trans(clnt->trans_mod);
188 			clnt->trans_mod = v9fs_get_trans_by_name(s);
189 			if (!clnt->trans_mod) {
190 				pr_info("Could not find request transport: %s\n",
191 					s);
192 				ret = -EINVAL;
193 			}
194 			kfree(s);
195 			break;
196 		case Opt_legacy:
197 			clnt->proto_version = p9_proto_legacy;
198 			break;
199 		case Opt_version:
200 			s = match_strdup(&args[0]);
201 			if (!s) {
202 				ret = -ENOMEM;
203 				p9_debug(P9_DEBUG_ERROR,
204 					 "problem allocating copy of version arg\n");
205 				goto free_and_return;
206 			}
207 			r = get_protocol_version(s);
208 			if (r < 0)
209 				ret = r;
210 			else
211 				clnt->proto_version = r;
212 			kfree(s);
213 			break;
214 		default:
215 			continue;
216 		}
217 	}
218 
219 free_and_return:
220 	if (ret)
221 		v9fs_put_trans(clnt->trans_mod);
222 	kfree(tmp_options);
223 	return ret;
224 }
225 
226 static int p9_fcall_init(struct p9_client *c, struct p9_fcall *fc,
227 			 int alloc_msize)
228 {
229 	if (likely(c->fcall_cache) && alloc_msize == c->msize) {
230 		fc->sdata = kmem_cache_alloc(c->fcall_cache, GFP_NOFS);
231 		fc->cache = c->fcall_cache;
232 	} else {
233 		fc->sdata = kmalloc(alloc_msize, GFP_NOFS);
234 		fc->cache = NULL;
235 	}
236 	if (!fc->sdata)
237 		return -ENOMEM;
238 	fc->capacity = alloc_msize;
239 	fc->id = 0;
240 	fc->tag = P9_NOTAG;
241 	return 0;
242 }
243 
244 void p9_fcall_fini(struct p9_fcall *fc)
245 {
246 	/* sdata can be NULL for interrupted requests in trans_rdma,
247 	 * and kmem_cache_free does not do NULL-check for us
248 	 */
249 	if (unlikely(!fc->sdata))
250 		return;
251 
252 	if (fc->cache)
253 		kmem_cache_free(fc->cache, fc->sdata);
254 	else
255 		kfree(fc->sdata);
256 }
257 EXPORT_SYMBOL(p9_fcall_fini);
258 
259 static struct kmem_cache *p9_req_cache;
260 
261 /**
262  * p9_tag_alloc - Allocate a new request.
263  * @c: Client session.
264  * @type: Transaction type.
265  * @t_size: Buffer size for holding this request
266  * (automatic calculation by format template if 0).
267  * @r_size: Buffer size for holding server's reply on this request
268  * (automatic calculation by format template if 0).
269  * @fmt: Format template for assembling 9p request message
270  * (see p9pdu_vwritef).
271  * @ap: Variable arguments to be fed to passed format template
272  * (see p9pdu_vwritef).
273  *
274  * Context: Process context.
275  * Return: Pointer to new request.
276  */
277 static struct p9_req_t *
278 p9_tag_alloc(struct p9_client *c, int8_t type, uint t_size, uint r_size,
279 	      const char *fmt, va_list ap)
280 {
281 	struct p9_req_t *req = kmem_cache_alloc(p9_req_cache, GFP_NOFS);
282 	int alloc_tsize;
283 	int alloc_rsize;
284 	int tag;
285 	va_list apc;
286 
287 	va_copy(apc, ap);
288 	alloc_tsize = min_t(size_t, c->msize,
289 			    t_size ?: p9_msg_buf_size(c, type, fmt, apc));
290 	va_end(apc);
291 
292 	alloc_rsize = min_t(size_t, c->msize,
293 			    r_size ?: p9_msg_buf_size(c, type + 1, fmt, ap));
294 
295 	if (!req)
296 		return ERR_PTR(-ENOMEM);
297 
298 	if (p9_fcall_init(c, &req->tc, alloc_tsize))
299 		goto free_req;
300 	if (p9_fcall_init(c, &req->rc, alloc_rsize))
301 		goto free;
302 
303 	p9pdu_reset(&req->tc);
304 	p9pdu_reset(&req->rc);
305 	req->t_err = 0;
306 	req->status = REQ_STATUS_ALLOC;
307 	/* refcount needs to be set to 0 before inserting into the idr
308 	 * so p9_tag_lookup does not accept a request that is not fully
309 	 * initialized. refcount_set to 2 below will mark request ready.
310 	 */
311 	refcount_set(&req->refcount, 0);
312 	init_waitqueue_head(&req->wq);
313 	INIT_LIST_HEAD(&req->req_list);
314 
315 	idr_preload(GFP_NOFS);
316 	spin_lock_irq(&c->lock);
317 	if (type == P9_TVERSION)
318 		tag = idr_alloc(&c->reqs, req, P9_NOTAG, P9_NOTAG + 1,
319 				GFP_NOWAIT);
320 	else
321 		tag = idr_alloc(&c->reqs, req, 0, P9_NOTAG, GFP_NOWAIT);
322 	req->tc.tag = tag;
323 	spin_unlock_irq(&c->lock);
324 	idr_preload_end();
325 	if (tag < 0)
326 		goto free;
327 
328 	/* Init ref to two because in the general case there is one ref
329 	 * that is put asynchronously by a writer thread, one ref
330 	 * temporarily given by p9_tag_lookup and put by p9_client_cb
331 	 * in the recv thread, and one ref put by p9_req_put in the
332 	 * main thread. The only exception is virtio that does not use
333 	 * p9_tag_lookup but does not have a writer thread either
334 	 * (the write happens synchronously in the request/zc_request
335 	 * callback), so p9_client_cb eats the second ref there
336 	 * as the pointer is duplicated directly by virtqueue_add_sgs()
337 	 */
338 	refcount_set(&req->refcount, 2);
339 
340 	return req;
341 
342 free:
343 	p9_fcall_fini(&req->tc);
344 	p9_fcall_fini(&req->rc);
345 free_req:
346 	kmem_cache_free(p9_req_cache, req);
347 	return ERR_PTR(-ENOMEM);
348 }
349 
350 /**
351  * p9_tag_lookup - Look up a request by tag.
352  * @c: Client session.
353  * @tag: Transaction ID.
354  *
355  * Context: Any context.
356  * Return: A request, or %NULL if there is no request with that tag.
357  */
358 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
359 {
360 	struct p9_req_t *req;
361 
362 	rcu_read_lock();
363 again:
364 	req = idr_find(&c->reqs, tag);
365 	if (req) {
366 		/* We have to be careful with the req found under rcu_read_lock
367 		 * Thanks to SLAB_TYPESAFE_BY_RCU we can safely try to get the
368 		 * ref again without corrupting other data, then check again
369 		 * that the tag matches once we have the ref
370 		 */
371 		if (!p9_req_try_get(req))
372 			goto again;
373 		if (req->tc.tag != tag) {
374 			p9_req_put(c, req);
375 			goto again;
376 		}
377 	}
378 	rcu_read_unlock();
379 
380 	return req;
381 }
382 EXPORT_SYMBOL(p9_tag_lookup);
383 
384 /**
385  * p9_tag_remove - Remove a tag.
386  * @c: Client session.
387  * @r: Request of reference.
388  *
389  * Context: Any context.
390  */
391 static void p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
392 {
393 	unsigned long flags;
394 	u16 tag = r->tc.tag;
395 
396 	p9_debug(P9_DEBUG_MUX, "freeing clnt %p req %p tag: %d\n", c, r, tag);
397 	spin_lock_irqsave(&c->lock, flags);
398 	idr_remove(&c->reqs, tag);
399 	spin_unlock_irqrestore(&c->lock, flags);
400 }
401 
402 int p9_req_put(struct p9_client *c, struct p9_req_t *r)
403 {
404 	if (refcount_dec_and_test(&r->refcount)) {
405 		p9_tag_remove(c, r);
406 
407 		p9_fcall_fini(&r->tc);
408 		p9_fcall_fini(&r->rc);
409 		kmem_cache_free(p9_req_cache, r);
410 		return 1;
411 	}
412 	return 0;
413 }
414 EXPORT_SYMBOL(p9_req_put);
415 
416 /**
417  * p9_tag_cleanup - cleans up tags structure and reclaims resources
418  * @c:  v9fs client struct
419  *
420  * This frees resources associated with the tags structure
421  *
422  */
423 static void p9_tag_cleanup(struct p9_client *c)
424 {
425 	struct p9_req_t *req;
426 	int id;
427 
428 	rcu_read_lock();
429 	idr_for_each_entry(&c->reqs, req, id) {
430 		pr_info("Tag %d still in use\n", id);
431 		if (p9_req_put(c, req) == 0)
432 			pr_warn("Packet with tag %d has still references",
433 				req->tc.tag);
434 	}
435 	rcu_read_unlock();
436 }
437 
438 /**
439  * p9_client_cb - call back from transport to client
440  * @c: client state
441  * @req: request received
442  * @status: request status, one of REQ_STATUS_*
443  *
444  */
445 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
446 {
447 	p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc.tag);
448 
449 	/* This barrier is needed to make sure any change made to req before
450 	 * the status change is visible to another thread
451 	 */
452 	smp_wmb();
453 	WRITE_ONCE(req->status, status);
454 
455 	wake_up(&req->wq);
456 	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
457 	p9_req_put(c, req);
458 }
459 EXPORT_SYMBOL(p9_client_cb);
460 
461 /**
462  * p9_parse_header - parse header arguments out of a packet
463  * @pdu: packet to parse
464  * @size: size of packet
465  * @type: type of request
466  * @tag: tag of packet
467  * @rewind: set if we need to rewind offset afterwards
468  */
469 
470 int
471 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type,
472 		int16_t *tag, int rewind)
473 {
474 	s8 r_type;
475 	s16 r_tag;
476 	s32 r_size;
477 	int offset = pdu->offset;
478 	int err;
479 
480 	pdu->offset = 0;
481 
482 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
483 	if (err)
484 		goto rewind_and_exit;
485 
486 	if (type)
487 		*type = r_type;
488 	if (tag)
489 		*tag = r_tag;
490 	if (size)
491 		*size = r_size;
492 
493 	if (pdu->size != r_size || r_size < 7) {
494 		err = -EINVAL;
495 		goto rewind_and_exit;
496 	}
497 
498 	pdu->id = r_type;
499 	pdu->tag = r_tag;
500 
501 	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
502 		 pdu->size, pdu->id, pdu->tag);
503 
504 rewind_and_exit:
505 	if (rewind)
506 		pdu->offset = offset;
507 	return err;
508 }
509 EXPORT_SYMBOL(p9_parse_header);
510 
511 /**
512  * p9_check_errors - check 9p packet for error return and process it
513  * @c: current client instance
514  * @req: request to parse and check for error conditions
515  *
516  * returns error code if one is discovered, otherwise returns 0
517  *
518  * this will have to be more complicated if we have multiple
519  * error packet types
520  */
521 
522 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
523 {
524 	s8 type;
525 	int err;
526 	int ecode;
527 
528 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
529 	if (req->rc.size > req->rc.capacity && !req->rc.zc) {
530 		pr_err("requested packet size too big: %d does not fit %zu (type=%d)\n",
531 		       req->rc.size, req->rc.capacity, req->rc.id);
532 		return -EIO;
533 	}
534 	/* dump the response from server
535 	 * This should be after check errors which poplulate pdu_fcall.
536 	 */
537 	trace_9p_protocol_dump(c, &req->rc);
538 	if (err) {
539 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
540 		return err;
541 	}
542 	if (type != P9_RERROR && type != P9_RLERROR)
543 		return 0;
544 
545 	if (!p9_is_proto_dotl(c)) {
546 		char *ename = NULL;
547 
548 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
549 				  &ename, &ecode);
550 		if (err) {
551 			kfree(ename);
552 			goto out_err;
553 		}
554 
555 		if (p9_is_proto_dotu(c) && ecode < 512)
556 			err = -ecode;
557 
558 		if (!err) {
559 			err = p9_errstr2errno(ename, strlen(ename));
560 
561 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
562 				 -ecode, ename);
563 		}
564 		kfree(ename);
565 	} else {
566 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
567 		if (err)
568 			goto out_err;
569 		err = -ecode;
570 
571 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
572 	}
573 
574 	return err;
575 
576 out_err:
577 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
578 
579 	return err;
580 }
581 
582 static struct p9_req_t *
583 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
584 
585 /**
586  * p9_client_flush - flush (cancel) a request
587  * @c: client state
588  * @oldreq: request to cancel
589  *
590  * This sents a flush for a particular request and links
591  * the flush request to the original request.  The current
592  * code only supports a single flush request although the protocol
593  * allows for multiple flush requests to be sent for a single request.
594  *
595  */
596 
597 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
598 {
599 	struct p9_req_t *req;
600 	s16 oldtag;
601 	int err;
602 
603 	err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
604 	if (err)
605 		return err;
606 
607 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
608 
609 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
610 	if (IS_ERR(req))
611 		return PTR_ERR(req);
612 
613 	/* if we haven't received a response for oldreq,
614 	 * remove it from the list
615 	 */
616 	if (READ_ONCE(oldreq->status) == REQ_STATUS_SENT) {
617 		if (c->trans_mod->cancelled)
618 			c->trans_mod->cancelled(c, oldreq);
619 	}
620 
621 	p9_req_put(c, req);
622 	return 0;
623 }
624 
625 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
626 					      int8_t type, uint t_size, uint r_size,
627 					      const char *fmt, va_list ap)
628 {
629 	int err;
630 	struct p9_req_t *req;
631 	va_list apc;
632 
633 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
634 
635 	/* we allow for any status other than disconnected */
636 	if (c->status == Disconnected)
637 		return ERR_PTR(-EIO);
638 
639 	/* if status is begin_disconnected we allow only clunk request */
640 	if (c->status == BeginDisconnect && type != P9_TCLUNK)
641 		return ERR_PTR(-EIO);
642 
643 	va_copy(apc, ap);
644 	req = p9_tag_alloc(c, type, t_size, r_size, fmt, apc);
645 	va_end(apc);
646 	if (IS_ERR(req))
647 		return req;
648 
649 	/* marshall the data */
650 	p9pdu_prepare(&req->tc, req->tc.tag, type);
651 	err = p9pdu_vwritef(&req->tc, c->proto_version, fmt, ap);
652 	if (err)
653 		goto reterr;
654 	p9pdu_finalize(c, &req->tc);
655 	trace_9p_client_req(c, type, req->tc.tag);
656 	return req;
657 reterr:
658 	p9_req_put(c, req);
659 	/* We have to put also the 2nd reference as it won't be used */
660 	p9_req_put(c, req);
661 	return ERR_PTR(err);
662 }
663 
664 /**
665  * p9_client_rpc - issue a request and wait for a response
666  * @c: client session
667  * @type: type of request
668  * @fmt: protocol format string (see protocol.c)
669  *
670  * Returns request structure (which client must free using p9_req_put)
671  */
672 
673 static struct p9_req_t *
674 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
675 {
676 	va_list ap;
677 	int sigpending, err;
678 	unsigned long flags;
679 	struct p9_req_t *req;
680 	/* Passing zero for tsize/rsize to p9_client_prepare_req() tells it to
681 	 * auto determine an appropriate (small) request/response size
682 	 * according to actual message data being sent. Currently RDMA
683 	 * transport is excluded from this response message size optimization,
684 	 * as it would not cope with it, due to its pooled response buffers
685 	 * (using an optimized request size for RDMA as well though).
686 	 */
687 	const uint tsize = 0;
688 	const uint rsize = c->trans_mod->pooled_rbuffers ? c->msize : 0;
689 
690 	va_start(ap, fmt);
691 	req = p9_client_prepare_req(c, type, tsize, rsize, fmt, ap);
692 	va_end(ap);
693 	if (IS_ERR(req))
694 		return req;
695 
696 	req->tc.zc = false;
697 	req->rc.zc = false;
698 
699 	if (signal_pending(current)) {
700 		sigpending = 1;
701 		clear_thread_flag(TIF_SIGPENDING);
702 	} else {
703 		sigpending = 0;
704 	}
705 
706 	err = c->trans_mod->request(c, req);
707 	if (err < 0) {
708 		/* write won't happen */
709 		p9_req_put(c, req);
710 		if (err != -ERESTARTSYS && err != -EFAULT)
711 			c->status = Disconnected;
712 		goto recalc_sigpending;
713 	}
714 again:
715 	/* Wait for the response */
716 	err = wait_event_killable(req->wq,
717 				  READ_ONCE(req->status) >= REQ_STATUS_RCVD);
718 
719 	/* Make sure our req is coherent with regard to updates in other
720 	 * threads - echoes to wmb() in the callback
721 	 */
722 	smp_rmb();
723 
724 	if (err == -ERESTARTSYS && c->status == Connected &&
725 	    type == P9_TFLUSH) {
726 		sigpending = 1;
727 		clear_thread_flag(TIF_SIGPENDING);
728 		goto again;
729 	}
730 
731 	if (READ_ONCE(req->status) == REQ_STATUS_ERROR) {
732 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
733 		err = req->t_err;
734 	}
735 	if (err == -ERESTARTSYS && c->status == Connected) {
736 		p9_debug(P9_DEBUG_MUX, "flushing\n");
737 		sigpending = 1;
738 		clear_thread_flag(TIF_SIGPENDING);
739 
740 		if (c->trans_mod->cancel(c, req))
741 			p9_client_flush(c, req);
742 
743 		/* if we received the response anyway, don't signal error */
744 		if (READ_ONCE(req->status) == REQ_STATUS_RCVD)
745 			err = 0;
746 	}
747 recalc_sigpending:
748 	if (sigpending) {
749 		spin_lock_irqsave(&current->sighand->siglock, flags);
750 		recalc_sigpending();
751 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
752 	}
753 	if (err < 0)
754 		goto reterr;
755 
756 	err = p9_check_errors(c, req);
757 	trace_9p_client_res(c, type, req->rc.tag, err);
758 	if (!err)
759 		return req;
760 reterr:
761 	p9_req_put(c, req);
762 	return ERR_PTR(safe_errno(err));
763 }
764 
765 /**
766  * p9_client_zc_rpc - issue a request and wait for a response
767  * @c: client session
768  * @type: type of request
769  * @uidata: destination for zero copy read
770  * @uodata: source for zero copy write
771  * @inlen: read buffer size
772  * @olen: write buffer size
773  * @in_hdrlen: reader header size, This is the size of response protocol data
774  * @fmt: protocol format string (see protocol.c)
775  *
776  * Returns request structure (which client must free using p9_req_put)
777  */
778 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
779 					 struct iov_iter *uidata,
780 					 struct iov_iter *uodata,
781 					 int inlen, int olen, int in_hdrlen,
782 					 const char *fmt, ...)
783 {
784 	va_list ap;
785 	int sigpending, err;
786 	unsigned long flags;
787 	struct p9_req_t *req;
788 
789 	va_start(ap, fmt);
790 	/* We allocate a inline protocol data of only 4k bytes.
791 	 * The actual content is passed in zero-copy fashion.
792 	 */
793 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, P9_ZC_HDR_SZ, fmt, ap);
794 	va_end(ap);
795 	if (IS_ERR(req))
796 		return req;
797 
798 	req->tc.zc = true;
799 	req->rc.zc = true;
800 
801 	if (signal_pending(current)) {
802 		sigpending = 1;
803 		clear_thread_flag(TIF_SIGPENDING);
804 	} else {
805 		sigpending = 0;
806 	}
807 
808 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
809 				       inlen, olen, in_hdrlen);
810 	if (err < 0) {
811 		if (err == -EIO)
812 			c->status = Disconnected;
813 		if (err != -ERESTARTSYS)
814 			goto recalc_sigpending;
815 	}
816 	if (READ_ONCE(req->status) == REQ_STATUS_ERROR) {
817 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
818 		err = req->t_err;
819 	}
820 	if (err == -ERESTARTSYS && c->status == Connected) {
821 		p9_debug(P9_DEBUG_MUX, "flushing\n");
822 		sigpending = 1;
823 		clear_thread_flag(TIF_SIGPENDING);
824 
825 		if (c->trans_mod->cancel(c, req))
826 			p9_client_flush(c, req);
827 
828 		/* if we received the response anyway, don't signal error */
829 		if (READ_ONCE(req->status) == REQ_STATUS_RCVD)
830 			err = 0;
831 	}
832 recalc_sigpending:
833 	if (sigpending) {
834 		spin_lock_irqsave(&current->sighand->siglock, flags);
835 		recalc_sigpending();
836 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
837 	}
838 	if (err < 0)
839 		goto reterr;
840 
841 	err = p9_check_errors(c, req);
842 	trace_9p_client_res(c, type, req->rc.tag, err);
843 	if (!err)
844 		return req;
845 reterr:
846 	p9_req_put(c, req);
847 	return ERR_PTR(safe_errno(err));
848 }
849 
850 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
851 {
852 	int ret;
853 	struct p9_fid *fid;
854 
855 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
856 	fid = kzalloc(sizeof(*fid), GFP_KERNEL);
857 	if (!fid)
858 		return NULL;
859 
860 	fid->mode = -1;
861 	fid->uid = current_fsuid();
862 	fid->clnt = clnt;
863 	refcount_set(&fid->count, 1);
864 
865 	idr_preload(GFP_KERNEL);
866 	spin_lock_irq(&clnt->lock);
867 	ret = idr_alloc_u32(&clnt->fids, fid, &fid->fid, P9_NOFID - 1,
868 			    GFP_NOWAIT);
869 	spin_unlock_irq(&clnt->lock);
870 	idr_preload_end();
871 	if (!ret) {
872 		trace_9p_fid_ref(fid, P9_FID_REF_CREATE);
873 		return fid;
874 	}
875 
876 	kfree(fid);
877 	return NULL;
878 }
879 
880 static void p9_fid_destroy(struct p9_fid *fid)
881 {
882 	struct p9_client *clnt;
883 	unsigned long flags;
884 
885 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
886 	trace_9p_fid_ref(fid, P9_FID_REF_DESTROY);
887 	clnt = fid->clnt;
888 	spin_lock_irqsave(&clnt->lock, flags);
889 	idr_remove(&clnt->fids, fid->fid);
890 	spin_unlock_irqrestore(&clnt->lock, flags);
891 	kfree(fid->rdir);
892 	kfree(fid);
893 }
894 
895 /* We also need to export tracepoint symbols for tracepoint_enabled() */
896 EXPORT_TRACEPOINT_SYMBOL(9p_fid_ref);
897 
898 void do_trace_9p_fid_get(struct p9_fid *fid)
899 {
900 	trace_9p_fid_ref(fid, P9_FID_REF_GET);
901 }
902 EXPORT_SYMBOL(do_trace_9p_fid_get);
903 
904 void do_trace_9p_fid_put(struct p9_fid *fid)
905 {
906 	trace_9p_fid_ref(fid, P9_FID_REF_PUT);
907 }
908 EXPORT_SYMBOL(do_trace_9p_fid_put);
909 
910 static int p9_client_version(struct p9_client *c)
911 {
912 	int err;
913 	struct p9_req_t *req;
914 	char *version = NULL;
915 	int msize;
916 
917 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
918 		 c->msize, c->proto_version);
919 
920 	switch (c->proto_version) {
921 	case p9_proto_2000L:
922 		req = p9_client_rpc(c, P9_TVERSION, "ds",
923 				    c->msize, "9P2000.L");
924 		break;
925 	case p9_proto_2000u:
926 		req = p9_client_rpc(c, P9_TVERSION, "ds",
927 				    c->msize, "9P2000.u");
928 		break;
929 	case p9_proto_legacy:
930 		req = p9_client_rpc(c, P9_TVERSION, "ds",
931 				    c->msize, "9P2000");
932 		break;
933 	default:
934 		return -EINVAL;
935 	}
936 
937 	if (IS_ERR(req))
938 		return PTR_ERR(req);
939 
940 	err = p9pdu_readf(&req->rc, c->proto_version, "ds", &msize, &version);
941 	if (err) {
942 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
943 		trace_9p_protocol_dump(c, &req->rc);
944 		goto error;
945 	}
946 
947 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
948 	if (!strncmp(version, "9P2000.L", 8)) {
949 		c->proto_version = p9_proto_2000L;
950 	} else if (!strncmp(version, "9P2000.u", 8)) {
951 		c->proto_version = p9_proto_2000u;
952 	} else if (!strncmp(version, "9P2000", 6)) {
953 		c->proto_version = p9_proto_legacy;
954 	} else {
955 		p9_debug(P9_DEBUG_ERROR,
956 			 "server returned an unknown version: %s\n", version);
957 		err = -EREMOTEIO;
958 		goto error;
959 	}
960 
961 	if (msize < 4096) {
962 		p9_debug(P9_DEBUG_ERROR,
963 			 "server returned a msize < 4096: %d\n", msize);
964 		err = -EREMOTEIO;
965 		goto error;
966 	}
967 	if (msize < c->msize)
968 		c->msize = msize;
969 
970 error:
971 	kfree(version);
972 	p9_req_put(c, req);
973 
974 	return err;
975 }
976 
977 struct p9_client *p9_client_create(const char *dev_name, char *options)
978 {
979 	int err;
980 	struct p9_client *clnt;
981 	char *client_id;
982 
983 	clnt = kmalloc(sizeof(*clnt), GFP_KERNEL);
984 	if (!clnt)
985 		return ERR_PTR(-ENOMEM);
986 
987 	clnt->trans_mod = NULL;
988 	clnt->trans = NULL;
989 	clnt->fcall_cache = NULL;
990 
991 	client_id = utsname()->nodename;
992 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
993 
994 	spin_lock_init(&clnt->lock);
995 	idr_init(&clnt->fids);
996 	idr_init(&clnt->reqs);
997 
998 	err = parse_opts(options, clnt);
999 	if (err < 0)
1000 		goto free_client;
1001 
1002 	if (!clnt->trans_mod)
1003 		clnt->trans_mod = v9fs_get_default_trans();
1004 
1005 	if (!clnt->trans_mod) {
1006 		err = -EPROTONOSUPPORT;
1007 		p9_debug(P9_DEBUG_ERROR,
1008 			 "No transport defined or default transport\n");
1009 		goto free_client;
1010 	}
1011 
1012 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
1013 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
1014 
1015 	err = clnt->trans_mod->create(clnt, dev_name, options);
1016 	if (err)
1017 		goto put_trans;
1018 
1019 	if (clnt->msize > clnt->trans_mod->maxsize) {
1020 		clnt->msize = clnt->trans_mod->maxsize;
1021 		pr_info("Limiting 'msize' to %d as this is the maximum "
1022 			"supported by transport %s\n",
1023 			clnt->msize, clnt->trans_mod->name
1024 		);
1025 	}
1026 
1027 	if (clnt->msize < 4096) {
1028 		p9_debug(P9_DEBUG_ERROR,
1029 			 "Please specify a msize of at least 4k\n");
1030 		err = -EINVAL;
1031 		goto close_trans;
1032 	}
1033 
1034 	err = p9_client_version(clnt);
1035 	if (err)
1036 		goto close_trans;
1037 
1038 	/* P9_HDRSZ + 4 is the smallest packet header we can have that is
1039 	 * followed by data accessed from userspace by read
1040 	 */
1041 	clnt->fcall_cache =
1042 		kmem_cache_create_usercopy("9p-fcall-cache", clnt->msize,
1043 					   0, 0, P9_HDRSZ + 4,
1044 					   clnt->msize - (P9_HDRSZ + 4),
1045 					   NULL);
1046 
1047 	return clnt;
1048 
1049 close_trans:
1050 	clnt->trans_mod->close(clnt);
1051 put_trans:
1052 	v9fs_put_trans(clnt->trans_mod);
1053 free_client:
1054 	kfree(clnt);
1055 	return ERR_PTR(err);
1056 }
1057 EXPORT_SYMBOL(p9_client_create);
1058 
1059 void p9_client_destroy(struct p9_client *clnt)
1060 {
1061 	struct p9_fid *fid;
1062 	int id;
1063 
1064 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1065 
1066 	if (clnt->trans_mod)
1067 		clnt->trans_mod->close(clnt);
1068 
1069 	v9fs_put_trans(clnt->trans_mod);
1070 
1071 	idr_for_each_entry(&clnt->fids, fid, id) {
1072 		pr_info("Found fid %d not clunked\n", fid->fid);
1073 		p9_fid_destroy(fid);
1074 	}
1075 
1076 	p9_tag_cleanup(clnt);
1077 
1078 	kmem_cache_destroy(clnt->fcall_cache);
1079 	kfree(clnt);
1080 }
1081 EXPORT_SYMBOL(p9_client_destroy);
1082 
1083 void p9_client_disconnect(struct p9_client *clnt)
1084 {
1085 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1086 	clnt->status = Disconnected;
1087 }
1088 EXPORT_SYMBOL(p9_client_disconnect);
1089 
1090 void p9_client_begin_disconnect(struct p9_client *clnt)
1091 {
1092 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1093 	clnt->status = BeginDisconnect;
1094 }
1095 EXPORT_SYMBOL(p9_client_begin_disconnect);
1096 
1097 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1098 				const char *uname, kuid_t n_uname,
1099 				const char *aname)
1100 {
1101 	int err;
1102 	struct p9_req_t *req;
1103 	struct p9_fid *fid;
1104 	struct p9_qid qid;
1105 
1106 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1107 		 afid ? afid->fid : -1, uname, aname);
1108 	fid = p9_fid_create(clnt);
1109 	if (!fid) {
1110 		err = -ENOMEM;
1111 		goto error;
1112 	}
1113 	fid->uid = n_uname;
1114 
1115 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
1116 			    afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
1117 	if (IS_ERR(req)) {
1118 		err = PTR_ERR(req);
1119 		goto error;
1120 	}
1121 
1122 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", &qid);
1123 	if (err) {
1124 		trace_9p_protocol_dump(clnt, &req->rc);
1125 		p9_req_put(clnt, req);
1126 		goto error;
1127 	}
1128 
1129 	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
1130 		 qid.type, qid.path, qid.version);
1131 
1132 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1133 
1134 	p9_req_put(clnt, req);
1135 	return fid;
1136 
1137 error:
1138 	if (fid)
1139 		p9_fid_destroy(fid);
1140 	return ERR_PTR(err);
1141 }
1142 EXPORT_SYMBOL(p9_client_attach);
1143 
1144 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
1145 			      const unsigned char * const *wnames, int clone)
1146 {
1147 	int err;
1148 	struct p9_client *clnt;
1149 	struct p9_fid *fid;
1150 	struct p9_qid *wqids;
1151 	struct p9_req_t *req;
1152 	u16 nwqids, count;
1153 
1154 	wqids = NULL;
1155 	clnt = oldfid->clnt;
1156 	if (clone) {
1157 		fid = p9_fid_create(clnt);
1158 		if (!fid) {
1159 			err = -ENOMEM;
1160 			goto error;
1161 		}
1162 
1163 		fid->uid = oldfid->uid;
1164 	} else {
1165 		fid = oldfid;
1166 	}
1167 
1168 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1169 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1170 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1171 			    nwname, wnames);
1172 	if (IS_ERR(req)) {
1173 		err = PTR_ERR(req);
1174 		goto error;
1175 	}
1176 
1177 	err = p9pdu_readf(&req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1178 	if (err) {
1179 		trace_9p_protocol_dump(clnt, &req->rc);
1180 		p9_req_put(clnt, req);
1181 		goto clunk_fid;
1182 	}
1183 	p9_req_put(clnt, req);
1184 
1185 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1186 
1187 	if (nwqids != nwname) {
1188 		err = -ENOENT;
1189 		goto clunk_fid;
1190 	}
1191 
1192 	for (count = 0; count < nwqids; count++)
1193 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1194 			 count, wqids[count].type,
1195 			 wqids[count].path,
1196 			 wqids[count].version);
1197 
1198 	if (nwname)
1199 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1200 	else
1201 		memmove(&fid->qid, &oldfid->qid, sizeof(struct p9_qid));
1202 
1203 	kfree(wqids);
1204 	return fid;
1205 
1206 clunk_fid:
1207 	kfree(wqids);
1208 	p9_fid_put(fid);
1209 	fid = NULL;
1210 
1211 error:
1212 	if (fid && fid != oldfid)
1213 		p9_fid_destroy(fid);
1214 
1215 	return ERR_PTR(err);
1216 }
1217 EXPORT_SYMBOL(p9_client_walk);
1218 
1219 int p9_client_open(struct p9_fid *fid, int mode)
1220 {
1221 	int err;
1222 	struct p9_client *clnt;
1223 	struct p9_req_t *req;
1224 	struct p9_qid qid;
1225 	int iounit;
1226 
1227 	clnt = fid->clnt;
1228 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1229 		 p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1230 
1231 	if (fid->mode != -1)
1232 		return -EINVAL;
1233 
1234 	if (p9_is_proto_dotl(clnt))
1235 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode & P9L_MODE_MASK);
1236 	else
1237 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode & P9L_MODE_MASK);
1238 	if (IS_ERR(req)) {
1239 		err = PTR_ERR(req);
1240 		goto error;
1241 	}
1242 
1243 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1244 	if (err) {
1245 		trace_9p_protocol_dump(clnt, &req->rc);
1246 		goto free_and_error;
1247 	}
1248 
1249 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1250 		 p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1251 		 qid.path, qid.version, iounit);
1252 
1253 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1254 	fid->mode = mode;
1255 	fid->iounit = iounit;
1256 
1257 free_and_error:
1258 	p9_req_put(clnt, req);
1259 error:
1260 	return err;
1261 }
1262 EXPORT_SYMBOL(p9_client_open);
1263 
1264 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags,
1265 			  u32 mode, kgid_t gid, struct p9_qid *qid)
1266 {
1267 	int err;
1268 	struct p9_client *clnt;
1269 	struct p9_req_t *req;
1270 	int iounit;
1271 
1272 	p9_debug(P9_DEBUG_9P,
1273 		 ">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1274 		 ofid->fid, name, flags, mode,
1275 		 from_kgid(&init_user_ns, gid));
1276 	clnt = ofid->clnt;
1277 
1278 	if (ofid->mode != -1)
1279 		return -EINVAL;
1280 
1281 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1282 			    mode & P9L_MODE_MASK, gid);
1283 	if (IS_ERR(req)) {
1284 		err = PTR_ERR(req);
1285 		goto error;
1286 	}
1287 
1288 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", qid, &iounit);
1289 	if (err) {
1290 		trace_9p_protocol_dump(clnt, &req->rc);
1291 		goto free_and_error;
1292 	}
1293 
1294 	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1295 		 qid->type, qid->path, qid->version, iounit);
1296 
1297 	memmove(&ofid->qid, qid, sizeof(struct p9_qid));
1298 	ofid->mode = flags;
1299 	ofid->iounit = iounit;
1300 
1301 free_and_error:
1302 	p9_req_put(clnt, req);
1303 error:
1304 	return err;
1305 }
1306 EXPORT_SYMBOL(p9_client_create_dotl);
1307 
1308 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1309 		     char *extension)
1310 {
1311 	int err;
1312 	struct p9_client *clnt;
1313 	struct p9_req_t *req;
1314 	struct p9_qid qid;
1315 	int iounit;
1316 
1317 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1318 		 fid->fid, name, perm, mode);
1319 	clnt = fid->clnt;
1320 
1321 	if (fid->mode != -1)
1322 		return -EINVAL;
1323 
1324 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1325 			    mode & P9L_MODE_MASK, extension);
1326 	if (IS_ERR(req)) {
1327 		err = PTR_ERR(req);
1328 		goto error;
1329 	}
1330 
1331 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1332 	if (err) {
1333 		trace_9p_protocol_dump(clnt, &req->rc);
1334 		goto free_and_error;
1335 	}
1336 
1337 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1338 		 qid.type, qid.path, qid.version, iounit);
1339 
1340 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1341 	fid->mode = mode;
1342 	fid->iounit = iounit;
1343 
1344 free_and_error:
1345 	p9_req_put(clnt, req);
1346 error:
1347 	return err;
1348 }
1349 EXPORT_SYMBOL(p9_client_fcreate);
1350 
1351 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1352 		      const char *symtgt, kgid_t gid, struct p9_qid *qid)
1353 {
1354 	int err;
1355 	struct p9_client *clnt;
1356 	struct p9_req_t *req;
1357 
1358 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1359 		 dfid->fid, name, symtgt);
1360 	clnt = dfid->clnt;
1361 
1362 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1363 			    gid);
1364 	if (IS_ERR(req)) {
1365 		err = PTR_ERR(req);
1366 		goto error;
1367 	}
1368 
1369 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
1370 	if (err) {
1371 		trace_9p_protocol_dump(clnt, &req->rc);
1372 		goto free_and_error;
1373 	}
1374 
1375 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1376 		 qid->type, qid->path, qid->version);
1377 
1378 free_and_error:
1379 	p9_req_put(clnt, req);
1380 error:
1381 	return err;
1382 }
1383 EXPORT_SYMBOL(p9_client_symlink);
1384 
1385 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1386 {
1387 	struct p9_client *clnt;
1388 	struct p9_req_t *req;
1389 
1390 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1391 		 dfid->fid, oldfid->fid, newname);
1392 	clnt = dfid->clnt;
1393 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1394 			    newname);
1395 	if (IS_ERR(req))
1396 		return PTR_ERR(req);
1397 
1398 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1399 	p9_req_put(clnt, req);
1400 	return 0;
1401 }
1402 EXPORT_SYMBOL(p9_client_link);
1403 
1404 int p9_client_fsync(struct p9_fid *fid, int datasync)
1405 {
1406 	int err = 0;
1407 	struct p9_client *clnt;
1408 	struct p9_req_t *req;
1409 
1410 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1411 		 fid->fid, datasync);
1412 	clnt = fid->clnt;
1413 
1414 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1415 	if (IS_ERR(req)) {
1416 		err = PTR_ERR(req);
1417 		goto error;
1418 	}
1419 
1420 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1421 
1422 	p9_req_put(clnt, req);
1423 
1424 error:
1425 	return err;
1426 }
1427 EXPORT_SYMBOL(p9_client_fsync);
1428 
1429 int p9_client_clunk(struct p9_fid *fid)
1430 {
1431 	int err = 0;
1432 	struct p9_client *clnt;
1433 	struct p9_req_t *req;
1434 	int retries = 0;
1435 
1436 again:
1437 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n",
1438 		 fid->fid, retries);
1439 	clnt = fid->clnt;
1440 
1441 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1442 	if (IS_ERR(req)) {
1443 		err = PTR_ERR(req);
1444 		goto error;
1445 	}
1446 
1447 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1448 
1449 	p9_req_put(clnt, req);
1450 error:
1451 	/* Fid is not valid even after a failed clunk
1452 	 * If interrupted, retry once then give up and
1453 	 * leak fid until umount.
1454 	 */
1455 	if (err == -ERESTARTSYS) {
1456 		if (retries++ == 0)
1457 			goto again;
1458 	} else {
1459 		p9_fid_destroy(fid);
1460 	}
1461 	return err;
1462 }
1463 EXPORT_SYMBOL(p9_client_clunk);
1464 
1465 int p9_client_remove(struct p9_fid *fid)
1466 {
1467 	int err = 0;
1468 	struct p9_client *clnt;
1469 	struct p9_req_t *req;
1470 
1471 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1472 	clnt = fid->clnt;
1473 
1474 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1475 	if (IS_ERR(req)) {
1476 		err = PTR_ERR(req);
1477 		goto error;
1478 	}
1479 
1480 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1481 
1482 	p9_req_put(clnt, req);
1483 error:
1484 	if (err == -ERESTARTSYS)
1485 		p9_fid_put(fid);
1486 	else
1487 		p9_fid_destroy(fid);
1488 	return err;
1489 }
1490 EXPORT_SYMBOL(p9_client_remove);
1491 
1492 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1493 {
1494 	int err = 0;
1495 	struct p9_req_t *req;
1496 	struct p9_client *clnt;
1497 
1498 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1499 		 dfid->fid, name, flags);
1500 
1501 	clnt = dfid->clnt;
1502 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1503 	if (IS_ERR(req)) {
1504 		err = PTR_ERR(req);
1505 		goto error;
1506 	}
1507 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1508 
1509 	p9_req_put(clnt, req);
1510 error:
1511 	return err;
1512 }
1513 EXPORT_SYMBOL(p9_client_unlinkat);
1514 
1515 int
1516 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1517 {
1518 	int total = 0;
1519 	*err = 0;
1520 
1521 	while (iov_iter_count(to)) {
1522 		int count;
1523 
1524 		count = p9_client_read_once(fid, offset, to, err);
1525 		if (!count || *err)
1526 			break;
1527 		offset += count;
1528 		total += count;
1529 	}
1530 	return total;
1531 }
1532 EXPORT_SYMBOL(p9_client_read);
1533 
1534 int
1535 p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
1536 		    int *err)
1537 {
1538 	struct p9_client *clnt = fid->clnt;
1539 	struct p9_req_t *req;
1540 	int count = iov_iter_count(to);
1541 	int rsize, received, non_zc = 0;
1542 	char *dataptr;
1543 
1544 	*err = 0;
1545 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %zu\n",
1546 		 fid->fid, offset, iov_iter_count(to));
1547 
1548 	rsize = fid->iounit;
1549 	if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1550 		rsize = clnt->msize - P9_IOHDRSZ;
1551 
1552 	if (count < rsize)
1553 		rsize = count;
1554 
1555 	/* Don't bother zerocopy for small IO (< 1024) */
1556 	if (clnt->trans_mod->zc_request && rsize > 1024) {
1557 		/* response header len is 11
1558 		 * PDU Header(7) + IO Size (4)
1559 		 */
1560 		req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1561 				       0, 11, "dqd", fid->fid,
1562 				       offset, rsize);
1563 	} else {
1564 		non_zc = 1;
1565 		req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1566 				    rsize);
1567 	}
1568 	if (IS_ERR(req)) {
1569 		*err = PTR_ERR(req);
1570 		if (!non_zc)
1571 			iov_iter_revert(to, count - iov_iter_count(to));
1572 		return 0;
1573 	}
1574 
1575 	*err = p9pdu_readf(&req->rc, clnt->proto_version,
1576 			   "D", &received, &dataptr);
1577 	if (*err) {
1578 		if (!non_zc)
1579 			iov_iter_revert(to, count - iov_iter_count(to));
1580 		trace_9p_protocol_dump(clnt, &req->rc);
1581 		p9_req_put(clnt, req);
1582 		return 0;
1583 	}
1584 	if (rsize < received) {
1585 		pr_err("bogus RREAD count (%d > %d)\n", received, rsize);
1586 		received = rsize;
1587 	}
1588 
1589 	p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", received);
1590 
1591 	if (non_zc) {
1592 		int n = copy_to_iter(dataptr, received, to);
1593 
1594 		if (n != received) {
1595 			*err = -EFAULT;
1596 			p9_req_put(clnt, req);
1597 			return n;
1598 		}
1599 	} else {
1600 		iov_iter_revert(to, count - received - iov_iter_count(to));
1601 	}
1602 	p9_req_put(clnt, req);
1603 	return received;
1604 }
1605 EXPORT_SYMBOL(p9_client_read_once);
1606 
1607 int
1608 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1609 {
1610 	struct p9_client *clnt = fid->clnt;
1611 	struct p9_req_t *req;
1612 	int total = 0;
1613 	*err = 0;
1614 
1615 	while (iov_iter_count(from)) {
1616 		int count = iov_iter_count(from);
1617 		int rsize = fid->iounit;
1618 		int written;
1619 
1620 		if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1621 			rsize = clnt->msize - P9_IOHDRSZ;
1622 
1623 		if (count < rsize)
1624 			rsize = count;
1625 
1626 		p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %d (/%d)\n",
1627 			 fid->fid, offset, rsize, count);
1628 
1629 		/* Don't bother zerocopy for small IO (< 1024) */
1630 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1631 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1632 					       rsize, P9_ZC_HDR_SZ, "dqd",
1633 					       fid->fid, offset, rsize);
1634 		} else {
1635 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1636 					    offset, rsize, from);
1637 		}
1638 		if (IS_ERR(req)) {
1639 			iov_iter_revert(from, count - iov_iter_count(from));
1640 			*err = PTR_ERR(req);
1641 			break;
1642 		}
1643 
1644 		*err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &written);
1645 		if (*err) {
1646 			iov_iter_revert(from, count - iov_iter_count(from));
1647 			trace_9p_protocol_dump(clnt, &req->rc);
1648 			p9_req_put(clnt, req);
1649 			break;
1650 		}
1651 		if (rsize < written) {
1652 			pr_err("bogus RWRITE count (%d > %d)\n", written, rsize);
1653 			written = rsize;
1654 		}
1655 
1656 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", written);
1657 
1658 		p9_req_put(clnt, req);
1659 		iov_iter_revert(from, count - written - iov_iter_count(from));
1660 		total += written;
1661 		offset += written;
1662 	}
1663 	return total;
1664 }
1665 EXPORT_SYMBOL(p9_client_write);
1666 
1667 void
1668 p9_client_write_subreq(struct netfs_io_subrequest *subreq)
1669 {
1670 	struct netfs_io_request *wreq = subreq->rreq;
1671 	struct p9_fid *fid = wreq->netfs_priv;
1672 	struct p9_client *clnt = fid->clnt;
1673 	struct p9_req_t *req;
1674 	unsigned long long start = subreq->start + subreq->transferred;
1675 	int written, len = subreq->len - subreq->transferred;
1676 	int err;
1677 
1678 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu len %d\n",
1679 		 fid->fid, start, len);
1680 
1681 	/* Don't bother zerocopy for small IO (< 1024) */
1682 	if (clnt->trans_mod->zc_request && len > 1024) {
1683 		req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, &subreq->io_iter,
1684 				       0, wreq->len, P9_ZC_HDR_SZ, "dqd",
1685 				       fid->fid, start, len);
1686 	} else {
1687 		req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1688 				    start, len, &subreq->io_iter);
1689 	}
1690 	if (IS_ERR(req)) {
1691 		netfs_write_subrequest_terminated(subreq, PTR_ERR(req), false);
1692 		return;
1693 	}
1694 
1695 	err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &written);
1696 	if (err) {
1697 		trace_9p_protocol_dump(clnt, &req->rc);
1698 		p9_req_put(clnt, req);
1699 		netfs_write_subrequest_terminated(subreq, err, false);
1700 		return;
1701 	}
1702 
1703 	if (written > len) {
1704 		pr_err("bogus RWRITE count (%d > %u)\n", written, len);
1705 		written = len;
1706 	}
1707 
1708 	p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", len);
1709 
1710 	p9_req_put(clnt, req);
1711 	netfs_write_subrequest_terminated(subreq, written, false);
1712 }
1713 EXPORT_SYMBOL(p9_client_write_subreq);
1714 
1715 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1716 {
1717 	int err;
1718 	struct p9_client *clnt;
1719 	struct p9_wstat *ret;
1720 	struct p9_req_t *req;
1721 	u16 ignored;
1722 
1723 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1724 
1725 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1726 	if (!ret)
1727 		return ERR_PTR(-ENOMEM);
1728 
1729 	clnt = fid->clnt;
1730 
1731 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1732 	if (IS_ERR(req)) {
1733 		err = PTR_ERR(req);
1734 		goto error;
1735 	}
1736 
1737 	err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
1738 	if (err) {
1739 		trace_9p_protocol_dump(clnt, &req->rc);
1740 		p9_req_put(clnt, req);
1741 		goto error;
1742 	}
1743 
1744 	p9_debug(P9_DEBUG_9P,
1745 		 "<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1746 		 "<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1747 		 "<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1748 		 "<<<    uid=%d gid=%d n_muid=%d\n",
1749 		 ret->size, ret->type, ret->dev, ret->qid.type, ret->qid.path,
1750 		 ret->qid.version, ret->mode,
1751 		 ret->atime, ret->mtime, ret->length,
1752 		 ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1753 		 from_kuid(&init_user_ns, ret->n_uid),
1754 		 from_kgid(&init_user_ns, ret->n_gid),
1755 		 from_kuid(&init_user_ns, ret->n_muid));
1756 
1757 	p9_req_put(clnt, req);
1758 	return ret;
1759 
1760 error:
1761 	kfree(ret);
1762 	return ERR_PTR(err);
1763 }
1764 EXPORT_SYMBOL(p9_client_stat);
1765 
1766 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1767 					    u64 request_mask)
1768 {
1769 	int err;
1770 	struct p9_client *clnt;
1771 	struct p9_stat_dotl *ret;
1772 	struct p9_req_t *req;
1773 
1774 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1775 		 fid->fid, request_mask);
1776 
1777 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1778 	if (!ret)
1779 		return ERR_PTR(-ENOMEM);
1780 
1781 	clnt = fid->clnt;
1782 
1783 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1784 	if (IS_ERR(req)) {
1785 		err = PTR_ERR(req);
1786 		goto error;
1787 	}
1788 
1789 	err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
1790 	if (err) {
1791 		trace_9p_protocol_dump(clnt, &req->rc);
1792 		p9_req_put(clnt, req);
1793 		goto error;
1794 	}
1795 
1796 	p9_debug(P9_DEBUG_9P, "<<< RGETATTR st_result_mask=%lld\n"
1797 		 "<<< qid=%x.%llx.%x\n"
1798 		 "<<< st_mode=%8.8x st_nlink=%llu\n"
1799 		 "<<< st_uid=%d st_gid=%d\n"
1800 		 "<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1801 		 "<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1802 		 "<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1803 		 "<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1804 		 "<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1805 		 "<<< st_gen=%lld st_data_version=%lld\n",
1806 		 ret->st_result_mask,
1807 		 ret->qid.type, ret->qid.path, ret->qid.version,
1808 		 ret->st_mode, ret->st_nlink,
1809 		 from_kuid(&init_user_ns, ret->st_uid),
1810 		 from_kgid(&init_user_ns, ret->st_gid),
1811 		 ret->st_rdev, ret->st_size, ret->st_blksize, ret->st_blocks,
1812 		 ret->st_atime_sec, ret->st_atime_nsec,
1813 		 ret->st_mtime_sec, ret->st_mtime_nsec,
1814 		 ret->st_ctime_sec, ret->st_ctime_nsec,
1815 		 ret->st_btime_sec, ret->st_btime_nsec,
1816 		 ret->st_gen, ret->st_data_version);
1817 
1818 	p9_req_put(clnt, req);
1819 	return ret;
1820 
1821 error:
1822 	kfree(ret);
1823 	return ERR_PTR(err);
1824 }
1825 EXPORT_SYMBOL(p9_client_getattr_dotl);
1826 
1827 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1828 {
1829 	int ret;
1830 
1831 	/* NOTE: size shouldn't include its own length */
1832 	/* size[2] type[2] dev[4] qid[13] */
1833 	/* mode[4] atime[4] mtime[4] length[8]*/
1834 	/* name[s] uid[s] gid[s] muid[s] */
1835 	ret = 2 + 4 + 13 + 4 + 4 + 4 + 8 + 2 + 2 + 2 + 2;
1836 
1837 	if (wst->name)
1838 		ret += strlen(wst->name);
1839 	if (wst->uid)
1840 		ret += strlen(wst->uid);
1841 	if (wst->gid)
1842 		ret += strlen(wst->gid);
1843 	if (wst->muid)
1844 		ret += strlen(wst->muid);
1845 
1846 	if (proto_version == p9_proto_2000u ||
1847 	    proto_version == p9_proto_2000L) {
1848 		/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1849 		ret += 2 + 4 + 4 + 4;
1850 		if (wst->extension)
1851 			ret += strlen(wst->extension);
1852 	}
1853 
1854 	return ret;
1855 }
1856 
1857 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1858 {
1859 	int err = 0;
1860 	struct p9_req_t *req;
1861 	struct p9_client *clnt;
1862 
1863 	clnt = fid->clnt;
1864 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1865 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n",
1866 		 fid->fid);
1867 	p9_debug(P9_DEBUG_9P,
1868 		 "     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1869 		 "     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1870 		 "     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1871 		 "     uid=%d gid=%d n_muid=%d\n",
1872 		 wst->size, wst->type, wst->dev, wst->qid.type,
1873 		 wst->qid.path, wst->qid.version,
1874 		 wst->mode, wst->atime, wst->mtime, wst->length,
1875 		 wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1876 		 from_kuid(&init_user_ns, wst->n_uid),
1877 		 from_kgid(&init_user_ns, wst->n_gid),
1878 		 from_kuid(&init_user_ns, wst->n_muid));
1879 
1880 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS",
1881 			    fid->fid, wst->size + 2, wst);
1882 	if (IS_ERR(req)) {
1883 		err = PTR_ERR(req);
1884 		goto error;
1885 	}
1886 
1887 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1888 
1889 	p9_req_put(clnt, req);
1890 error:
1891 	return err;
1892 }
1893 EXPORT_SYMBOL(p9_client_wstat);
1894 
1895 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1896 {
1897 	int err = 0;
1898 	struct p9_req_t *req;
1899 	struct p9_client *clnt;
1900 
1901 	clnt = fid->clnt;
1902 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1903 	p9_debug(P9_DEBUG_9P, "    valid=%x mode=%x uid=%d gid=%d size=%lld\n",
1904 		 p9attr->valid, p9attr->mode,
1905 		 from_kuid(&init_user_ns, p9attr->uid),
1906 		 from_kgid(&init_user_ns, p9attr->gid),
1907 		 p9attr->size);
1908 	p9_debug(P9_DEBUG_9P, "    atime_sec=%lld atime_nsec=%lld\n",
1909 		 p9attr->atime_sec, p9attr->atime_nsec);
1910 	p9_debug(P9_DEBUG_9P, "    mtime_sec=%lld mtime_nsec=%lld\n",
1911 		 p9attr->mtime_sec, p9attr->mtime_nsec);
1912 
1913 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1914 
1915 	if (IS_ERR(req)) {
1916 		err = PTR_ERR(req);
1917 		goto error;
1918 	}
1919 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1920 	p9_req_put(clnt, req);
1921 error:
1922 	return err;
1923 }
1924 EXPORT_SYMBOL(p9_client_setattr);
1925 
1926 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1927 {
1928 	int err;
1929 	struct p9_req_t *req;
1930 	struct p9_client *clnt;
1931 
1932 	clnt = fid->clnt;
1933 
1934 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1935 
1936 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1937 	if (IS_ERR(req)) {
1938 		err = PTR_ERR(req);
1939 		goto error;
1940 	}
1941 
1942 	err = p9pdu_readf(&req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1943 			  &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1944 			  &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1945 	if (err) {
1946 		trace_9p_protocol_dump(clnt, &req->rc);
1947 		p9_req_put(clnt, req);
1948 		goto error;
1949 	}
1950 
1951 	p9_debug(P9_DEBUG_9P,
1952 		 "<<< RSTATFS fid %d type 0x%x bsize %u blocks %llu bfree %llu bavail %llu files %llu ffree %llu fsid %llu namelen %u\n",
1953 		 fid->fid, sb->type, sb->bsize, sb->blocks, sb->bfree,
1954 		 sb->bavail, sb->files, sb->ffree, sb->fsid, sb->namelen);
1955 
1956 	p9_req_put(clnt, req);
1957 error:
1958 	return err;
1959 }
1960 EXPORT_SYMBOL(p9_client_statfs);
1961 
1962 int p9_client_rename(struct p9_fid *fid,
1963 		     struct p9_fid *newdirfid, const char *name)
1964 {
1965 	int err = 0;
1966 	struct p9_req_t *req;
1967 	struct p9_client *clnt;
1968 
1969 	clnt = fid->clnt;
1970 
1971 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1972 		 fid->fid, newdirfid->fid, name);
1973 
1974 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1975 			    newdirfid->fid, name);
1976 	if (IS_ERR(req)) {
1977 		err = PTR_ERR(req);
1978 		goto error;
1979 	}
1980 
1981 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1982 
1983 	p9_req_put(clnt, req);
1984 error:
1985 	return err;
1986 }
1987 EXPORT_SYMBOL(p9_client_rename);
1988 
1989 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
1990 		       struct p9_fid *newdirfid, const char *new_name)
1991 {
1992 	int err = 0;
1993 	struct p9_req_t *req;
1994 	struct p9_client *clnt;
1995 
1996 	clnt = olddirfid->clnt;
1997 
1998 	p9_debug(P9_DEBUG_9P,
1999 		 ">>> TRENAMEAT olddirfid %d old name %s newdirfid %d new name %s\n",
2000 		 olddirfid->fid, old_name, newdirfid->fid, new_name);
2001 
2002 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
2003 			    old_name, newdirfid->fid, new_name);
2004 	if (IS_ERR(req)) {
2005 		err = PTR_ERR(req);
2006 		goto error;
2007 	}
2008 
2009 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
2010 		 newdirfid->fid, new_name);
2011 
2012 	p9_req_put(clnt, req);
2013 error:
2014 	return err;
2015 }
2016 EXPORT_SYMBOL(p9_client_renameat);
2017 
2018 /* An xattrwalk without @attr_name gives the fid for the lisxattr namespace
2019  */
2020 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
2021 				   const char *attr_name, u64 *attr_size)
2022 {
2023 	int err;
2024 	struct p9_req_t *req;
2025 	struct p9_client *clnt;
2026 	struct p9_fid *attr_fid;
2027 
2028 	clnt = file_fid->clnt;
2029 	attr_fid = p9_fid_create(clnt);
2030 	if (!attr_fid) {
2031 		err = -ENOMEM;
2032 		goto error;
2033 	}
2034 	p9_debug(P9_DEBUG_9P,
2035 		 ">>> TXATTRWALK file_fid %d, attr_fid %d name '%s'\n",
2036 		 file_fid->fid, attr_fid->fid, attr_name);
2037 
2038 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
2039 			    file_fid->fid, attr_fid->fid, attr_name);
2040 	if (IS_ERR(req)) {
2041 		err = PTR_ERR(req);
2042 		goto error;
2043 	}
2044 	err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
2045 	if (err) {
2046 		trace_9p_protocol_dump(clnt, &req->rc);
2047 		p9_req_put(clnt, req);
2048 		goto clunk_fid;
2049 	}
2050 	p9_req_put(clnt, req);
2051 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
2052 		 attr_fid->fid, *attr_size);
2053 	return attr_fid;
2054 clunk_fid:
2055 	p9_fid_put(attr_fid);
2056 	attr_fid = NULL;
2057 error:
2058 	if (attr_fid && attr_fid != file_fid)
2059 		p9_fid_destroy(attr_fid);
2060 
2061 	return ERR_PTR(err);
2062 }
2063 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
2064 
2065 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
2066 			  u64 attr_size, int flags)
2067 {
2068 	int err = 0;
2069 	struct p9_req_t *req;
2070 	struct p9_client *clnt;
2071 
2072 	p9_debug(P9_DEBUG_9P,
2073 		 ">>> TXATTRCREATE fid %d name  %s size %llu flag %d\n",
2074 		 fid->fid, name, attr_size, flags);
2075 	clnt = fid->clnt;
2076 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
2077 			    fid->fid, name, attr_size, flags);
2078 	if (IS_ERR(req)) {
2079 		err = PTR_ERR(req);
2080 		goto error;
2081 	}
2082 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
2083 	p9_req_put(clnt, req);
2084 error:
2085 	return err;
2086 }
2087 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
2088 
2089 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
2090 {
2091 	int err, rsize, non_zc = 0;
2092 	struct p9_client *clnt;
2093 	struct p9_req_t *req;
2094 	char *dataptr;
2095 	struct kvec kv = {.iov_base = data, .iov_len = count};
2096 	struct iov_iter to;
2097 
2098 	iov_iter_kvec(&to, ITER_DEST, &kv, 1, count);
2099 
2100 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
2101 		 fid->fid, offset, count);
2102 
2103 	clnt = fid->clnt;
2104 
2105 	rsize = fid->iounit;
2106 	if (!rsize || rsize > clnt->msize - P9_READDIRHDRSZ)
2107 		rsize = clnt->msize - P9_READDIRHDRSZ;
2108 
2109 	if (count < rsize)
2110 		rsize = count;
2111 
2112 	/* Don't bother zerocopy for small IO (< 1024) */
2113 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2114 		/* response header len is 11
2115 		 * PDU Header(7) + IO Size (4)
2116 		 */
2117 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2118 				       11, "dqd", fid->fid, offset, rsize);
2119 	} else {
2120 		non_zc = 1;
2121 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2122 				    offset, rsize);
2123 	}
2124 	if (IS_ERR(req)) {
2125 		err = PTR_ERR(req);
2126 		goto error;
2127 	}
2128 
2129 	err = p9pdu_readf(&req->rc, clnt->proto_version, "D", &count, &dataptr);
2130 	if (err) {
2131 		trace_9p_protocol_dump(clnt, &req->rc);
2132 		goto free_and_error;
2133 	}
2134 	if (rsize < count) {
2135 		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
2136 		count = rsize;
2137 	}
2138 
2139 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
2140 
2141 	if (non_zc)
2142 		memmove(data, dataptr, count);
2143 
2144 	p9_req_put(clnt, req);
2145 	return count;
2146 
2147 free_and_error:
2148 	p9_req_put(clnt, req);
2149 error:
2150 	return err;
2151 }
2152 EXPORT_SYMBOL(p9_client_readdir);
2153 
2154 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2155 			 dev_t rdev, kgid_t gid, struct p9_qid *qid)
2156 {
2157 	int err;
2158 	struct p9_client *clnt;
2159 	struct p9_req_t *req;
2160 
2161 	clnt = fid->clnt;
2162 	p9_debug(P9_DEBUG_9P,
2163 		 ">>> TMKNOD fid %d name %s mode %d major %d minor %d\n",
2164 		 fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2165 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2166 			    MAJOR(rdev), MINOR(rdev), gid);
2167 	if (IS_ERR(req))
2168 		return PTR_ERR(req);
2169 
2170 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2171 	if (err) {
2172 		trace_9p_protocol_dump(clnt, &req->rc);
2173 		goto error;
2174 	}
2175 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n",
2176 		 qid->type, qid->path, qid->version);
2177 
2178 error:
2179 	p9_req_put(clnt, req);
2180 	return err;
2181 }
2182 EXPORT_SYMBOL(p9_client_mknod_dotl);
2183 
2184 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2185 			 kgid_t gid, struct p9_qid *qid)
2186 {
2187 	int err;
2188 	struct p9_client *clnt;
2189 	struct p9_req_t *req;
2190 
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_req_put(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 	clnt = fid->clnt;
2220 	p9_debug(P9_DEBUG_9P,
2221 		 ">>> TLOCK fid %d type %i flags %d start %lld length %lld proc_id %d client_id %s\n",
2222 		 fid->fid, flock->type, flock->flags, flock->start,
2223 		 flock->length, flock->proc_id, flock->client_id);
2224 
2225 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2226 			    flock->flags, flock->start, flock->length,
2227 			    flock->proc_id, flock->client_id);
2228 
2229 	if (IS_ERR(req))
2230 		return PTR_ERR(req);
2231 
2232 	err = p9pdu_readf(&req->rc, clnt->proto_version, "b", status);
2233 	if (err) {
2234 		trace_9p_protocol_dump(clnt, &req->rc);
2235 		goto error;
2236 	}
2237 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2238 error:
2239 	p9_req_put(clnt, req);
2240 	return err;
2241 }
2242 EXPORT_SYMBOL(p9_client_lock_dotl);
2243 
2244 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2245 {
2246 	int err;
2247 	struct p9_client *clnt;
2248 	struct p9_req_t *req;
2249 
2250 	clnt = fid->clnt;
2251 	p9_debug(P9_DEBUG_9P,
2252 		 ">>> TGETLOCK fid %d, type %i start %lld length %lld proc_id %d client_id %s\n",
2253 		 fid->fid, glock->type, glock->start, glock->length,
2254 		 glock->proc_id, glock->client_id);
2255 
2256 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,
2257 			    glock->type, glock->start, glock->length,
2258 			    glock->proc_id, glock->client_id);
2259 
2260 	if (IS_ERR(req))
2261 		return PTR_ERR(req);
2262 
2263 	err = p9pdu_readf(&req->rc, clnt->proto_version, "bqqds", &glock->type,
2264 			  &glock->start, &glock->length, &glock->proc_id,
2265 			  &glock->client_id);
2266 	if (err) {
2267 		trace_9p_protocol_dump(clnt, &req->rc);
2268 		goto error;
2269 	}
2270 	p9_debug(P9_DEBUG_9P,
2271 		 "<<< RGETLOCK type %i start %lld length %lld proc_id %d client_id %s\n",
2272 		 glock->type, glock->start, glock->length,
2273 		 glock->proc_id, glock->client_id);
2274 error:
2275 	p9_req_put(clnt, req);
2276 	return err;
2277 }
2278 EXPORT_SYMBOL(p9_client_getlock_dotl);
2279 
2280 int p9_client_readlink(struct p9_fid *fid, char **target)
2281 {
2282 	int err;
2283 	struct p9_client *clnt;
2284 	struct p9_req_t *req;
2285 
2286 	clnt = fid->clnt;
2287 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2288 
2289 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2290 	if (IS_ERR(req))
2291 		return PTR_ERR(req);
2292 
2293 	err = p9pdu_readf(&req->rc, clnt->proto_version, "s", target);
2294 	if (err) {
2295 		trace_9p_protocol_dump(clnt, &req->rc);
2296 		goto error;
2297 	}
2298 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2299 error:
2300 	p9_req_put(clnt, req);
2301 	return err;
2302 }
2303 EXPORT_SYMBOL(p9_client_readlink);
2304 
2305 int __init p9_client_init(void)
2306 {
2307 	p9_req_cache = KMEM_CACHE(p9_req_t, SLAB_TYPESAFE_BY_RCU);
2308 	return p9_req_cache ? 0 : -ENOMEM;
2309 }
2310 
2311 void __exit p9_client_exit(void)
2312 {
2313 	kmem_cache_destroy(p9_req_cache);
2314 }
2315