xref: /openbmc/linux/net/9p/client.c (revision f3531d1a)
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  * @t_size: Buffer size for holding this request
259  * (automatic calculation by format template if 0).
260  * @r_size: Buffer size for holding server's reply on this request
261  * (automatic calculation by format template if 0).
262  * @fmt: Format template for assembling 9p request message
263  * (see p9pdu_vwritef).
264  * @ap: Variable arguments to be fed to passed format template
265  * (see p9pdu_vwritef).
266  *
267  * Context: Process context.
268  * Return: Pointer to new request.
269  */
270 static struct p9_req_t *
271 p9_tag_alloc(struct p9_client *c, int8_t type, uint t_size, uint r_size,
272 	      const char *fmt, va_list ap)
273 {
274 	struct p9_req_t *req = kmem_cache_alloc(p9_req_cache, GFP_NOFS);
275 	int alloc_tsize;
276 	int alloc_rsize;
277 	int tag;
278 	va_list apc;
279 
280 	va_copy(apc, ap);
281 	alloc_tsize = min_t(size_t, c->msize,
282 			    t_size ?: p9_msg_buf_size(c, type, fmt, apc));
283 	va_end(apc);
284 
285 	alloc_rsize = min_t(size_t, c->msize,
286 			    r_size ?: p9_msg_buf_size(c, type + 1, fmt, ap));
287 
288 	if (!req)
289 		return ERR_PTR(-ENOMEM);
290 
291 	if (p9_fcall_init(c, &req->tc, alloc_tsize))
292 		goto free_req;
293 	if (p9_fcall_init(c, &req->rc, alloc_rsize))
294 		goto free;
295 
296 	p9pdu_reset(&req->tc);
297 	p9pdu_reset(&req->rc);
298 	req->t_err = 0;
299 	req->status = REQ_STATUS_ALLOC;
300 	/* refcount needs to be set to 0 before inserting into the idr
301 	 * so p9_tag_lookup does not accept a request that is not fully
302 	 * initialized. refcount_set to 2 below will mark request ready.
303 	 */
304 	refcount_set(&req->refcount, 0);
305 	init_waitqueue_head(&req->wq);
306 	INIT_LIST_HEAD(&req->req_list);
307 
308 	idr_preload(GFP_NOFS);
309 	spin_lock_irq(&c->lock);
310 	if (type == P9_TVERSION)
311 		tag = idr_alloc(&c->reqs, req, P9_NOTAG, P9_NOTAG + 1,
312 				GFP_NOWAIT);
313 	else
314 		tag = idr_alloc(&c->reqs, req, 0, P9_NOTAG, GFP_NOWAIT);
315 	req->tc.tag = tag;
316 	spin_unlock_irq(&c->lock);
317 	idr_preload_end();
318 	if (tag < 0)
319 		goto free;
320 
321 	/* Init ref to two because in the general case there is one ref
322 	 * that is put asynchronously by a writer thread, one ref
323 	 * temporarily given by p9_tag_lookup and put by p9_client_cb
324 	 * in the recv thread, and one ref put by p9_req_put in the
325 	 * main thread. The only exception is virtio that does not use
326 	 * p9_tag_lookup but does not have a writer thread either
327 	 * (the write happens synchronously in the request/zc_request
328 	 * callback), so p9_client_cb eats the second ref there
329 	 * as the pointer is duplicated directly by virtqueue_add_sgs()
330 	 */
331 	refcount_set(&req->refcount, 2);
332 
333 	return req;
334 
335 free:
336 	p9_fcall_fini(&req->tc);
337 	p9_fcall_fini(&req->rc);
338 free_req:
339 	kmem_cache_free(p9_req_cache, req);
340 	return ERR_PTR(-ENOMEM);
341 }
342 
343 /**
344  * p9_tag_lookup - Look up a request by tag.
345  * @c: Client session.
346  * @tag: Transaction ID.
347  *
348  * Context: Any context.
349  * Return: A request, or %NULL if there is no request with that tag.
350  */
351 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
352 {
353 	struct p9_req_t *req;
354 
355 	rcu_read_lock();
356 again:
357 	req = idr_find(&c->reqs, tag);
358 	if (req) {
359 		/* We have to be careful with the req found under rcu_read_lock
360 		 * Thanks to SLAB_TYPESAFE_BY_RCU we can safely try to get the
361 		 * ref again without corrupting other data, then check again
362 		 * that the tag matches once we have the ref
363 		 */
364 		if (!p9_req_try_get(req))
365 			goto again;
366 		if (req->tc.tag != tag) {
367 			p9_req_put(c, req);
368 			goto again;
369 		}
370 	}
371 	rcu_read_unlock();
372 
373 	return req;
374 }
375 EXPORT_SYMBOL(p9_tag_lookup);
376 
377 /**
378  * p9_tag_remove - Remove a tag.
379  * @c: Client session.
380  * @r: Request of reference.
381  *
382  * Context: Any context.
383  */
384 static void p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
385 {
386 	unsigned long flags;
387 	u16 tag = r->tc.tag;
388 
389 	p9_debug(P9_DEBUG_MUX, "freeing clnt %p req %p tag: %d\n", c, r, tag);
390 	spin_lock_irqsave(&c->lock, flags);
391 	idr_remove(&c->reqs, tag);
392 	spin_unlock_irqrestore(&c->lock, flags);
393 }
394 
395 int p9_req_put(struct p9_client *c, struct p9_req_t *r)
396 {
397 	if (refcount_dec_and_test(&r->refcount)) {
398 		p9_tag_remove(c, r);
399 
400 		p9_fcall_fini(&r->tc);
401 		p9_fcall_fini(&r->rc);
402 		kmem_cache_free(p9_req_cache, r);
403 		return 1;
404 	}
405 	return 0;
406 }
407 EXPORT_SYMBOL(p9_req_put);
408 
409 /**
410  * p9_tag_cleanup - cleans up tags structure and reclaims resources
411  * @c:  v9fs client struct
412  *
413  * This frees resources associated with the tags structure
414  *
415  */
416 static void p9_tag_cleanup(struct p9_client *c)
417 {
418 	struct p9_req_t *req;
419 	int id;
420 
421 	rcu_read_lock();
422 	idr_for_each_entry(&c->reqs, req, id) {
423 		pr_info("Tag %d still in use\n", id);
424 		if (p9_req_put(c, req) == 0)
425 			pr_warn("Packet with tag %d has still references",
426 				req->tc.tag);
427 	}
428 	rcu_read_unlock();
429 }
430 
431 /**
432  * p9_client_cb - call back from transport to client
433  * @c: client state
434  * @req: request received
435  * @status: request status, one of REQ_STATUS_*
436  *
437  */
438 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
439 {
440 	p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc.tag);
441 
442 	/* This barrier is needed to make sure any change made to req before
443 	 * the status change is visible to another thread
444 	 */
445 	smp_wmb();
446 	WRITE_ONCE(req->status, status);
447 
448 	wake_up(&req->wq);
449 	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
450 	p9_req_put(c, req);
451 }
452 EXPORT_SYMBOL(p9_client_cb);
453 
454 /**
455  * p9_parse_header - parse header arguments out of a packet
456  * @pdu: packet to parse
457  * @size: size of packet
458  * @type: type of request
459  * @tag: tag of packet
460  * @rewind: set if we need to rewind offset afterwards
461  */
462 
463 int
464 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type,
465 		int16_t *tag, int rewind)
466 {
467 	s8 r_type;
468 	s16 r_tag;
469 	s32 r_size;
470 	int offset = pdu->offset;
471 	int err;
472 
473 	pdu->offset = 0;
474 
475 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
476 	if (err)
477 		goto rewind_and_exit;
478 
479 	if (type)
480 		*type = r_type;
481 	if (tag)
482 		*tag = r_tag;
483 	if (size)
484 		*size = r_size;
485 
486 	if (pdu->size != r_size || r_size < 7) {
487 		err = -EINVAL;
488 		goto rewind_and_exit;
489 	}
490 
491 	pdu->id = r_type;
492 	pdu->tag = r_tag;
493 
494 	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
495 		 pdu->size, pdu->id, pdu->tag);
496 
497 rewind_and_exit:
498 	if (rewind)
499 		pdu->offset = offset;
500 	return err;
501 }
502 EXPORT_SYMBOL(p9_parse_header);
503 
504 /**
505  * p9_check_errors - check 9p packet for error return and process it
506  * @c: current client instance
507  * @req: request to parse and check for error conditions
508  *
509  * returns error code if one is discovered, otherwise returns 0
510  *
511  * this will have to be more complicated if we have multiple
512  * error packet types
513  */
514 
515 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
516 {
517 	s8 type;
518 	int err;
519 	int ecode;
520 
521 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
522 	if (req->rc.size > req->rc.capacity && !req->rc.zc) {
523 		pr_err("requested packet size too big: %d does not fit %zu (type=%d)\n",
524 		       req->rc.size, req->rc.capacity, req->rc.id);
525 		return -EIO;
526 	}
527 	/* dump the response from server
528 	 * This should be after check errors which poplulate pdu_fcall.
529 	 */
530 	trace_9p_protocol_dump(c, &req->rc);
531 	if (err) {
532 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
533 		return err;
534 	}
535 	if (type != P9_RERROR && type != P9_RLERROR)
536 		return 0;
537 
538 	if (!p9_is_proto_dotl(c)) {
539 		char *ename;
540 
541 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
542 				  &ename, &ecode);
543 		if (err)
544 			goto out_err;
545 
546 		if (p9_is_proto_dotu(c) && ecode < 512)
547 			err = -ecode;
548 
549 		if (!err) {
550 			err = p9_errstr2errno(ename, strlen(ename));
551 
552 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
553 				 -ecode, ename);
554 		}
555 		kfree(ename);
556 	} else {
557 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
558 		if (err)
559 			goto out_err;
560 		err = -ecode;
561 
562 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
563 	}
564 
565 	return err;
566 
567 out_err:
568 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
569 
570 	return err;
571 }
572 
573 static struct p9_req_t *
574 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
575 
576 /**
577  * p9_client_flush - flush (cancel) a request
578  * @c: client state
579  * @oldreq: request to cancel
580  *
581  * This sents a flush for a particular request and links
582  * the flush request to the original request.  The current
583  * code only supports a single flush request although the protocol
584  * allows for multiple flush requests to be sent for a single request.
585  *
586  */
587 
588 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
589 {
590 	struct p9_req_t *req;
591 	s16 oldtag;
592 	int err;
593 
594 	err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
595 	if (err)
596 		return err;
597 
598 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
599 
600 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
601 	if (IS_ERR(req))
602 		return PTR_ERR(req);
603 
604 	/* if we haven't received a response for oldreq,
605 	 * remove it from the list
606 	 */
607 	if (READ_ONCE(oldreq->status) == REQ_STATUS_SENT) {
608 		if (c->trans_mod->cancelled)
609 			c->trans_mod->cancelled(c, oldreq);
610 	}
611 
612 	p9_req_put(c, req);
613 	return 0;
614 }
615 
616 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
617 					      int8_t type, uint t_size, uint r_size,
618 					      const char *fmt, va_list ap)
619 {
620 	int err;
621 	struct p9_req_t *req;
622 	va_list apc;
623 
624 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
625 
626 	/* we allow for any status other than disconnected */
627 	if (c->status == Disconnected)
628 		return ERR_PTR(-EIO);
629 
630 	/* if status is begin_disconnected we allow only clunk request */
631 	if (c->status == BeginDisconnect && type != P9_TCLUNK)
632 		return ERR_PTR(-EIO);
633 
634 	va_copy(apc, ap);
635 	req = p9_tag_alloc(c, type, t_size, r_size, fmt, apc);
636 	va_end(apc);
637 	if (IS_ERR(req))
638 		return req;
639 
640 	/* marshall the data */
641 	p9pdu_prepare(&req->tc, req->tc.tag, type);
642 	err = p9pdu_vwritef(&req->tc, c->proto_version, fmt, ap);
643 	if (err)
644 		goto reterr;
645 	p9pdu_finalize(c, &req->tc);
646 	trace_9p_client_req(c, type, req->tc.tag);
647 	return req;
648 reterr:
649 	p9_req_put(c, req);
650 	/* We have to put also the 2nd reference as it won't be used */
651 	p9_req_put(c, req);
652 	return ERR_PTR(err);
653 }
654 
655 /**
656  * p9_client_rpc - issue a request and wait for a response
657  * @c: client session
658  * @type: type of request
659  * @fmt: protocol format string (see protocol.c)
660  *
661  * Returns request structure (which client must free using p9_req_put)
662  */
663 
664 static struct p9_req_t *
665 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
666 {
667 	va_list ap;
668 	int sigpending, err;
669 	unsigned long flags;
670 	struct p9_req_t *req;
671 	/* Passing zero for tsize/rsize to p9_client_prepare_req() tells it to
672 	 * auto determine an appropriate (small) request/response size
673 	 * according to actual message data being sent. Currently RDMA
674 	 * transport is excluded from this response message size optimization,
675 	 * as it would not cope with it, due to its pooled response buffers
676 	 * (using an optimized request size for RDMA as well though).
677 	 */
678 	const uint tsize = 0;
679 	const uint rsize = c->trans_mod->pooled_rbuffers ? c->msize : 0;
680 
681 	va_start(ap, fmt);
682 	req = p9_client_prepare_req(c, type, tsize, rsize, fmt, ap);
683 	va_end(ap);
684 	if (IS_ERR(req))
685 		return req;
686 
687 	req->tc.zc = false;
688 	req->rc.zc = false;
689 
690 	if (signal_pending(current)) {
691 		sigpending = 1;
692 		clear_thread_flag(TIF_SIGPENDING);
693 	} else {
694 		sigpending = 0;
695 	}
696 
697 	err = c->trans_mod->request(c, req);
698 	if (err < 0) {
699 		/* write won't happen */
700 		p9_req_put(c, req);
701 		if (err != -ERESTARTSYS && err != -EFAULT)
702 			c->status = Disconnected;
703 		goto recalc_sigpending;
704 	}
705 again:
706 	/* Wait for the response */
707 	err = wait_event_killable(req->wq,
708 				  READ_ONCE(req->status) >= REQ_STATUS_RCVD);
709 
710 	/* Make sure our req is coherent with regard to updates in other
711 	 * threads - echoes to wmb() in the callback
712 	 */
713 	smp_rmb();
714 
715 	if (err == -ERESTARTSYS && c->status == Connected &&
716 	    type == P9_TFLUSH) {
717 		sigpending = 1;
718 		clear_thread_flag(TIF_SIGPENDING);
719 		goto again;
720 	}
721 
722 	if (READ_ONCE(req->status) == REQ_STATUS_ERROR) {
723 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
724 		err = req->t_err;
725 	}
726 	if (err == -ERESTARTSYS && c->status == Connected) {
727 		p9_debug(P9_DEBUG_MUX, "flushing\n");
728 		sigpending = 1;
729 		clear_thread_flag(TIF_SIGPENDING);
730 
731 		if (c->trans_mod->cancel(c, req))
732 			p9_client_flush(c, req);
733 
734 		/* if we received the response anyway, don't signal error */
735 		if (READ_ONCE(req->status) == REQ_STATUS_RCVD)
736 			err = 0;
737 	}
738 recalc_sigpending:
739 	if (sigpending) {
740 		spin_lock_irqsave(&current->sighand->siglock, flags);
741 		recalc_sigpending();
742 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
743 	}
744 	if (err < 0)
745 		goto reterr;
746 
747 	err = p9_check_errors(c, req);
748 	trace_9p_client_res(c, type, req->rc.tag, err);
749 	if (!err)
750 		return req;
751 reterr:
752 	p9_req_put(c, req);
753 	return ERR_PTR(safe_errno(err));
754 }
755 
756 /**
757  * p9_client_zc_rpc - issue a request and wait for a response
758  * @c: client session
759  * @type: type of request
760  * @uidata: destination for zero copy read
761  * @uodata: source for zero copy write
762  * @inlen: read buffer size
763  * @olen: write buffer size
764  * @in_hdrlen: reader header size, This is the size of response protocol data
765  * @fmt: protocol format string (see protocol.c)
766  *
767  * Returns request structure (which client must free using p9_req_put)
768  */
769 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
770 					 struct iov_iter *uidata,
771 					 struct iov_iter *uodata,
772 					 int inlen, int olen, int in_hdrlen,
773 					 const char *fmt, ...)
774 {
775 	va_list ap;
776 	int sigpending, err;
777 	unsigned long flags;
778 	struct p9_req_t *req;
779 
780 	va_start(ap, fmt);
781 	/* We allocate a inline protocol data of only 4k bytes.
782 	 * The actual content is passed in zero-copy fashion.
783 	 */
784 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, P9_ZC_HDR_SZ, fmt, ap);
785 	va_end(ap);
786 	if (IS_ERR(req))
787 		return req;
788 
789 	req->tc.zc = true;
790 	req->rc.zc = true;
791 
792 	if (signal_pending(current)) {
793 		sigpending = 1;
794 		clear_thread_flag(TIF_SIGPENDING);
795 	} else {
796 		sigpending = 0;
797 	}
798 
799 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
800 				       inlen, olen, in_hdrlen);
801 	if (err < 0) {
802 		if (err == -EIO)
803 			c->status = Disconnected;
804 		if (err != -ERESTARTSYS)
805 			goto recalc_sigpending;
806 	}
807 	if (READ_ONCE(req->status) == REQ_STATUS_ERROR) {
808 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
809 		err = req->t_err;
810 	}
811 	if (err == -ERESTARTSYS && c->status == Connected) {
812 		p9_debug(P9_DEBUG_MUX, "flushing\n");
813 		sigpending = 1;
814 		clear_thread_flag(TIF_SIGPENDING);
815 
816 		if (c->trans_mod->cancel(c, req))
817 			p9_client_flush(c, req);
818 
819 		/* if we received the response anyway, don't signal error */
820 		if (READ_ONCE(req->status) == REQ_STATUS_RCVD)
821 			err = 0;
822 	}
823 recalc_sigpending:
824 	if (sigpending) {
825 		spin_lock_irqsave(&current->sighand->siglock, flags);
826 		recalc_sigpending();
827 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
828 	}
829 	if (err < 0)
830 		goto reterr;
831 
832 	err = p9_check_errors(c, req);
833 	trace_9p_client_res(c, type, req->rc.tag, err);
834 	if (!err)
835 		return req;
836 reterr:
837 	p9_req_put(c, req);
838 	return ERR_PTR(safe_errno(err));
839 }
840 
841 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
842 {
843 	int ret;
844 	struct p9_fid *fid;
845 
846 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
847 	fid = kzalloc(sizeof(*fid), GFP_KERNEL);
848 	if (!fid)
849 		return NULL;
850 
851 	fid->mode = -1;
852 	fid->uid = current_fsuid();
853 	fid->clnt = clnt;
854 	refcount_set(&fid->count, 1);
855 
856 	idr_preload(GFP_KERNEL);
857 	spin_lock_irq(&clnt->lock);
858 	ret = idr_alloc_u32(&clnt->fids, fid, &fid->fid, P9_NOFID - 1,
859 			    GFP_NOWAIT);
860 	spin_unlock_irq(&clnt->lock);
861 	idr_preload_end();
862 	if (!ret) {
863 		trace_9p_fid_ref(fid, P9_FID_REF_CREATE);
864 		return fid;
865 	}
866 
867 	kfree(fid);
868 	return NULL;
869 }
870 
871 static void p9_fid_destroy(struct p9_fid *fid)
872 {
873 	struct p9_client *clnt;
874 	unsigned long flags;
875 
876 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
877 	trace_9p_fid_ref(fid, P9_FID_REF_DESTROY);
878 	clnt = fid->clnt;
879 	spin_lock_irqsave(&clnt->lock, flags);
880 	idr_remove(&clnt->fids, fid->fid);
881 	spin_unlock_irqrestore(&clnt->lock, flags);
882 	kfree(fid->rdir);
883 	kfree(fid);
884 }
885 
886 /* We also need to export tracepoint symbols for tracepoint_enabled() */
887 EXPORT_TRACEPOINT_SYMBOL(9p_fid_ref);
888 
889 void do_trace_9p_fid_get(struct p9_fid *fid)
890 {
891 	trace_9p_fid_ref(fid, P9_FID_REF_GET);
892 }
893 EXPORT_SYMBOL(do_trace_9p_fid_get);
894 
895 void do_trace_9p_fid_put(struct p9_fid *fid)
896 {
897 	trace_9p_fid_ref(fid, P9_FID_REF_PUT);
898 }
899 EXPORT_SYMBOL(do_trace_9p_fid_put);
900 
901 static int p9_client_version(struct p9_client *c)
902 {
903 	int err = 0;
904 	struct p9_req_t *req;
905 	char *version = NULL;
906 	int msize;
907 
908 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
909 		 c->msize, c->proto_version);
910 
911 	switch (c->proto_version) {
912 	case p9_proto_2000L:
913 		req = p9_client_rpc(c, P9_TVERSION, "ds",
914 				    c->msize, "9P2000.L");
915 		break;
916 	case p9_proto_2000u:
917 		req = p9_client_rpc(c, P9_TVERSION, "ds",
918 				    c->msize, "9P2000.u");
919 		break;
920 	case p9_proto_legacy:
921 		req = p9_client_rpc(c, P9_TVERSION, "ds",
922 				    c->msize, "9P2000");
923 		break;
924 	default:
925 		return -EINVAL;
926 	}
927 
928 	if (IS_ERR(req))
929 		return PTR_ERR(req);
930 
931 	err = p9pdu_readf(&req->rc, c->proto_version, "ds", &msize, &version);
932 	if (err) {
933 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
934 		trace_9p_protocol_dump(c, &req->rc);
935 		goto error;
936 	}
937 
938 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
939 	if (!strncmp(version, "9P2000.L", 8)) {
940 		c->proto_version = p9_proto_2000L;
941 	} else if (!strncmp(version, "9P2000.u", 8)) {
942 		c->proto_version = p9_proto_2000u;
943 	} else if (!strncmp(version, "9P2000", 6)) {
944 		c->proto_version = p9_proto_legacy;
945 	} else {
946 		p9_debug(P9_DEBUG_ERROR,
947 			 "server returned an unknown version: %s\n", version);
948 		err = -EREMOTEIO;
949 		goto error;
950 	}
951 
952 	if (msize < 4096) {
953 		p9_debug(P9_DEBUG_ERROR,
954 			 "server returned a msize < 4096: %d\n", msize);
955 		err = -EREMOTEIO;
956 		goto error;
957 	}
958 	if (msize < c->msize)
959 		c->msize = msize;
960 
961 error:
962 	kfree(version);
963 	p9_req_put(c, req);
964 
965 	return err;
966 }
967 
968 struct p9_client *p9_client_create(const char *dev_name, char *options)
969 {
970 	int err;
971 	struct p9_client *clnt;
972 	char *client_id;
973 
974 	err = 0;
975 	clnt = kmalloc(sizeof(*clnt), GFP_KERNEL);
976 	if (!clnt)
977 		return ERR_PTR(-ENOMEM);
978 
979 	clnt->trans_mod = NULL;
980 	clnt->trans = NULL;
981 	clnt->fcall_cache = NULL;
982 
983 	client_id = utsname()->nodename;
984 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
985 
986 	spin_lock_init(&clnt->lock);
987 	idr_init(&clnt->fids);
988 	idr_init(&clnt->reqs);
989 
990 	err = parse_opts(options, clnt);
991 	if (err < 0)
992 		goto free_client;
993 
994 	if (!clnt->trans_mod)
995 		clnt->trans_mod = v9fs_get_default_trans();
996 
997 	if (!clnt->trans_mod) {
998 		err = -EPROTONOSUPPORT;
999 		p9_debug(P9_DEBUG_ERROR,
1000 			 "No transport defined or default transport\n");
1001 		goto free_client;
1002 	}
1003 
1004 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
1005 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
1006 
1007 	err = clnt->trans_mod->create(clnt, dev_name, options);
1008 	if (err)
1009 		goto put_trans;
1010 
1011 	if (clnt->msize > clnt->trans_mod->maxsize) {
1012 		clnt->msize = clnt->trans_mod->maxsize;
1013 		pr_info("Limiting 'msize' to %d as this is the maximum "
1014 			"supported by transport %s\n",
1015 			clnt->msize, clnt->trans_mod->name
1016 		);
1017 	}
1018 
1019 	if (clnt->msize < 4096) {
1020 		p9_debug(P9_DEBUG_ERROR,
1021 			 "Please specify a msize of at least 4k\n");
1022 		err = -EINVAL;
1023 		goto close_trans;
1024 	}
1025 
1026 	err = p9_client_version(clnt);
1027 	if (err)
1028 		goto close_trans;
1029 
1030 	/* P9_HDRSZ + 4 is the smallest packet header we can have that is
1031 	 * followed by data accessed from userspace by read
1032 	 */
1033 	clnt->fcall_cache =
1034 		kmem_cache_create_usercopy("9p-fcall-cache", clnt->msize,
1035 					   0, 0, P9_HDRSZ + 4,
1036 					   clnt->msize - (P9_HDRSZ + 4),
1037 					   NULL);
1038 
1039 	return clnt;
1040 
1041 close_trans:
1042 	clnt->trans_mod->close(clnt);
1043 put_trans:
1044 	v9fs_put_trans(clnt->trans_mod);
1045 free_client:
1046 	kfree(clnt);
1047 	return ERR_PTR(err);
1048 }
1049 EXPORT_SYMBOL(p9_client_create);
1050 
1051 void p9_client_destroy(struct p9_client *clnt)
1052 {
1053 	struct p9_fid *fid;
1054 	int id;
1055 
1056 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1057 
1058 	if (clnt->trans_mod)
1059 		clnt->trans_mod->close(clnt);
1060 
1061 	v9fs_put_trans(clnt->trans_mod);
1062 
1063 	idr_for_each_entry(&clnt->fids, fid, id) {
1064 		pr_info("Found fid %d not clunked\n", fid->fid);
1065 		p9_fid_destroy(fid);
1066 	}
1067 
1068 	p9_tag_cleanup(clnt);
1069 
1070 	kmem_cache_destroy(clnt->fcall_cache);
1071 	kfree(clnt);
1072 }
1073 EXPORT_SYMBOL(p9_client_destroy);
1074 
1075 void p9_client_disconnect(struct p9_client *clnt)
1076 {
1077 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1078 	clnt->status = Disconnected;
1079 }
1080 EXPORT_SYMBOL(p9_client_disconnect);
1081 
1082 void p9_client_begin_disconnect(struct p9_client *clnt)
1083 {
1084 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1085 	clnt->status = BeginDisconnect;
1086 }
1087 EXPORT_SYMBOL(p9_client_begin_disconnect);
1088 
1089 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1090 				const char *uname, kuid_t n_uname,
1091 				const char *aname)
1092 {
1093 	int err = 0;
1094 	struct p9_req_t *req;
1095 	struct p9_fid *fid;
1096 	struct p9_qid qid;
1097 
1098 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1099 		 afid ? afid->fid : -1, uname, aname);
1100 	fid = p9_fid_create(clnt);
1101 	if (!fid) {
1102 		err = -ENOMEM;
1103 		goto error;
1104 	}
1105 	fid->uid = n_uname;
1106 
1107 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
1108 			    afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
1109 	if (IS_ERR(req)) {
1110 		err = PTR_ERR(req);
1111 		goto error;
1112 	}
1113 
1114 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", &qid);
1115 	if (err) {
1116 		trace_9p_protocol_dump(clnt, &req->rc);
1117 		p9_req_put(clnt, req);
1118 		goto error;
1119 	}
1120 
1121 	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
1122 		 qid.type, qid.path, qid.version);
1123 
1124 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1125 
1126 	p9_req_put(clnt, req);
1127 	return fid;
1128 
1129 error:
1130 	if (fid)
1131 		p9_fid_destroy(fid);
1132 	return ERR_PTR(err);
1133 }
1134 EXPORT_SYMBOL(p9_client_attach);
1135 
1136 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
1137 			      const unsigned char * const *wnames, int clone)
1138 {
1139 	int err;
1140 	struct p9_client *clnt;
1141 	struct p9_fid *fid;
1142 	struct p9_qid *wqids;
1143 	struct p9_req_t *req;
1144 	u16 nwqids, count;
1145 
1146 	err = 0;
1147 	wqids = NULL;
1148 	clnt = oldfid->clnt;
1149 	if (clone) {
1150 		fid = p9_fid_create(clnt);
1151 		if (!fid) {
1152 			err = -ENOMEM;
1153 			goto error;
1154 		}
1155 
1156 		fid->uid = oldfid->uid;
1157 	} else {
1158 		fid = oldfid;
1159 	}
1160 
1161 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1162 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1163 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1164 			    nwname, wnames);
1165 	if (IS_ERR(req)) {
1166 		err = PTR_ERR(req);
1167 		goto error;
1168 	}
1169 
1170 	err = p9pdu_readf(&req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1171 	if (err) {
1172 		trace_9p_protocol_dump(clnt, &req->rc);
1173 		p9_req_put(clnt, req);
1174 		goto clunk_fid;
1175 	}
1176 	p9_req_put(clnt, req);
1177 
1178 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1179 
1180 	if (nwqids != nwname) {
1181 		err = -ENOENT;
1182 		goto clunk_fid;
1183 	}
1184 
1185 	for (count = 0; count < nwqids; count++)
1186 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1187 			 count, wqids[count].type,
1188 			 wqids[count].path,
1189 			 wqids[count].version);
1190 
1191 	if (nwname)
1192 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1193 	else
1194 		memmove(&fid->qid, &oldfid->qid, sizeof(struct p9_qid));
1195 
1196 	kfree(wqids);
1197 	return fid;
1198 
1199 clunk_fid:
1200 	kfree(wqids);
1201 	p9_fid_put(fid);
1202 	fid = NULL;
1203 
1204 error:
1205 	if (fid && fid != oldfid)
1206 		p9_fid_destroy(fid);
1207 
1208 	return ERR_PTR(err);
1209 }
1210 EXPORT_SYMBOL(p9_client_walk);
1211 
1212 int p9_client_open(struct p9_fid *fid, int mode)
1213 {
1214 	int err;
1215 	struct p9_client *clnt;
1216 	struct p9_req_t *req;
1217 	struct p9_qid qid;
1218 	int iounit;
1219 
1220 	clnt = fid->clnt;
1221 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1222 		 p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1223 	err = 0;
1224 
1225 	if (fid->mode != -1)
1226 		return -EINVAL;
1227 
1228 	if (p9_is_proto_dotl(clnt))
1229 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode);
1230 	else
1231 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
1232 	if (IS_ERR(req)) {
1233 		err = PTR_ERR(req);
1234 		goto error;
1235 	}
1236 
1237 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1238 	if (err) {
1239 		trace_9p_protocol_dump(clnt, &req->rc);
1240 		goto free_and_error;
1241 	}
1242 
1243 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1244 		 p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1245 		 qid.path, qid.version, iounit);
1246 
1247 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1248 	fid->mode = mode;
1249 	fid->iounit = iounit;
1250 
1251 free_and_error:
1252 	p9_req_put(clnt, req);
1253 error:
1254 	return err;
1255 }
1256 EXPORT_SYMBOL(p9_client_open);
1257 
1258 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags,
1259 			  u32 mode, kgid_t gid, struct p9_qid *qid)
1260 {
1261 	int err = 0;
1262 	struct p9_client *clnt;
1263 	struct p9_req_t *req;
1264 	int iounit;
1265 
1266 	p9_debug(P9_DEBUG_9P,
1267 		 ">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1268 		 ofid->fid, name, flags, mode,
1269 		 from_kgid(&init_user_ns, gid));
1270 	clnt = ofid->clnt;
1271 
1272 	if (ofid->mode != -1)
1273 		return -EINVAL;
1274 
1275 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1276 			    mode, gid);
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, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1289 		 qid->type, qid->path, qid->version, iounit);
1290 
1291 	memmove(&ofid->qid, qid, sizeof(struct p9_qid));
1292 	ofid->mode = mode;
1293 	ofid->iounit = iounit;
1294 
1295 free_and_error:
1296 	p9_req_put(clnt, req);
1297 error:
1298 	return err;
1299 }
1300 EXPORT_SYMBOL(p9_client_create_dotl);
1301 
1302 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1303 		     char *extension)
1304 {
1305 	int err;
1306 	struct p9_client *clnt;
1307 	struct p9_req_t *req;
1308 	struct p9_qid qid;
1309 	int iounit;
1310 
1311 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1312 		 fid->fid, name, perm, mode);
1313 	err = 0;
1314 	clnt = fid->clnt;
1315 
1316 	if (fid->mode != -1)
1317 		return -EINVAL;
1318 
1319 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1320 			    mode, extension);
1321 	if (IS_ERR(req)) {
1322 		err = PTR_ERR(req);
1323 		goto error;
1324 	}
1325 
1326 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1327 	if (err) {
1328 		trace_9p_protocol_dump(clnt, &req->rc);
1329 		goto free_and_error;
1330 	}
1331 
1332 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1333 		 qid.type, qid.path, qid.version, iounit);
1334 
1335 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1336 	fid->mode = mode;
1337 	fid->iounit = iounit;
1338 
1339 free_and_error:
1340 	p9_req_put(clnt, req);
1341 error:
1342 	return err;
1343 }
1344 EXPORT_SYMBOL(p9_client_fcreate);
1345 
1346 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1347 		      const char *symtgt, kgid_t gid, struct p9_qid *qid)
1348 {
1349 	int err = 0;
1350 	struct p9_client *clnt;
1351 	struct p9_req_t *req;
1352 
1353 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1354 		 dfid->fid, name, symtgt);
1355 	clnt = dfid->clnt;
1356 
1357 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1358 			    gid);
1359 	if (IS_ERR(req)) {
1360 		err = PTR_ERR(req);
1361 		goto error;
1362 	}
1363 
1364 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
1365 	if (err) {
1366 		trace_9p_protocol_dump(clnt, &req->rc);
1367 		goto free_and_error;
1368 	}
1369 
1370 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1371 		 qid->type, qid->path, qid->version);
1372 
1373 free_and_error:
1374 	p9_req_put(clnt, req);
1375 error:
1376 	return err;
1377 }
1378 EXPORT_SYMBOL(p9_client_symlink);
1379 
1380 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1381 {
1382 	struct p9_client *clnt;
1383 	struct p9_req_t *req;
1384 
1385 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1386 		 dfid->fid, oldfid->fid, newname);
1387 	clnt = dfid->clnt;
1388 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1389 			    newname);
1390 	if (IS_ERR(req))
1391 		return PTR_ERR(req);
1392 
1393 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1394 	p9_req_put(clnt, req);
1395 	return 0;
1396 }
1397 EXPORT_SYMBOL(p9_client_link);
1398 
1399 int p9_client_fsync(struct p9_fid *fid, int datasync)
1400 {
1401 	int err;
1402 	struct p9_client *clnt;
1403 	struct p9_req_t *req;
1404 
1405 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1406 		 fid->fid, datasync);
1407 	err = 0;
1408 	clnt = fid->clnt;
1409 
1410 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1411 	if (IS_ERR(req)) {
1412 		err = PTR_ERR(req);
1413 		goto error;
1414 	}
1415 
1416 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1417 
1418 	p9_req_put(clnt, req);
1419 
1420 error:
1421 	return err;
1422 }
1423 EXPORT_SYMBOL(p9_client_fsync);
1424 
1425 int p9_client_clunk(struct p9_fid *fid)
1426 {
1427 	int err;
1428 	struct p9_client *clnt;
1429 	struct p9_req_t *req;
1430 	int retries = 0;
1431 
1432 again:
1433 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n",
1434 		 fid->fid, retries);
1435 	err = 0;
1436 	clnt = fid->clnt;
1437 
1438 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1439 	if (IS_ERR(req)) {
1440 		err = PTR_ERR(req);
1441 		goto error;
1442 	}
1443 
1444 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1445 
1446 	p9_req_put(clnt, req);
1447 error:
1448 	/* Fid is not valid even after a failed clunk
1449 	 * If interrupted, retry once then give up and
1450 	 * leak fid until umount.
1451 	 */
1452 	if (err == -ERESTARTSYS) {
1453 		if (retries++ == 0)
1454 			goto again;
1455 	} else {
1456 		p9_fid_destroy(fid);
1457 	}
1458 	return err;
1459 }
1460 EXPORT_SYMBOL(p9_client_clunk);
1461 
1462 int p9_client_remove(struct p9_fid *fid)
1463 {
1464 	int err;
1465 	struct p9_client *clnt;
1466 	struct p9_req_t *req;
1467 
1468 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1469 	err = 0;
1470 	clnt = fid->clnt;
1471 
1472 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1473 	if (IS_ERR(req)) {
1474 		err = PTR_ERR(req);
1475 		goto error;
1476 	}
1477 
1478 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1479 
1480 	p9_req_put(clnt, req);
1481 error:
1482 	if (err == -ERESTARTSYS)
1483 		p9_fid_put(fid);
1484 	else
1485 		p9_fid_destroy(fid);
1486 	return err;
1487 }
1488 EXPORT_SYMBOL(p9_client_remove);
1489 
1490 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1491 {
1492 	int err = 0;
1493 	struct p9_req_t *req;
1494 	struct p9_client *clnt;
1495 
1496 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1497 		 dfid->fid, name, flags);
1498 
1499 	clnt = dfid->clnt;
1500 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1501 	if (IS_ERR(req)) {
1502 		err = PTR_ERR(req);
1503 		goto error;
1504 	}
1505 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1506 
1507 	p9_req_put(clnt, req);
1508 error:
1509 	return err;
1510 }
1511 EXPORT_SYMBOL(p9_client_unlinkat);
1512 
1513 int
1514 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1515 {
1516 	int total = 0;
1517 	*err = 0;
1518 
1519 	while (iov_iter_count(to)) {
1520 		int count;
1521 
1522 		count = p9_client_read_once(fid, offset, to, err);
1523 		if (!count || *err)
1524 			break;
1525 		offset += count;
1526 		total += count;
1527 	}
1528 	return total;
1529 }
1530 EXPORT_SYMBOL(p9_client_read);
1531 
1532 int
1533 p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
1534 		    int *err)
1535 {
1536 	struct p9_client *clnt = fid->clnt;
1537 	struct p9_req_t *req;
1538 	int count = iov_iter_count(to);
1539 	int rsize, received, non_zc = 0;
1540 	char *dataptr;
1541 
1542 	*err = 0;
1543 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %zu\n",
1544 		 fid->fid, offset, iov_iter_count(to));
1545 
1546 	rsize = fid->iounit;
1547 	if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1548 		rsize = clnt->msize - P9_IOHDRSZ;
1549 
1550 	if (count < rsize)
1551 		rsize = count;
1552 
1553 	/* Don't bother zerocopy for small IO (< 1024) */
1554 	if (clnt->trans_mod->zc_request && rsize > 1024) {
1555 		/* response header len is 11
1556 		 * PDU Header(7) + IO Size (4)
1557 		 */
1558 		req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1559 				       0, 11, "dqd", fid->fid,
1560 				       offset, rsize);
1561 	} else {
1562 		non_zc = 1;
1563 		req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1564 				    rsize);
1565 	}
1566 	if (IS_ERR(req)) {
1567 		*err = PTR_ERR(req);
1568 		if (!non_zc)
1569 			iov_iter_revert(to, count - iov_iter_count(to));
1570 		return 0;
1571 	}
1572 
1573 	*err = p9pdu_readf(&req->rc, clnt->proto_version,
1574 			   "D", &received, &dataptr);
1575 	if (*err) {
1576 		if (!non_zc)
1577 			iov_iter_revert(to, count - iov_iter_count(to));
1578 		trace_9p_protocol_dump(clnt, &req->rc);
1579 		p9_req_put(clnt, req);
1580 		return 0;
1581 	}
1582 	if (rsize < received) {
1583 		pr_err("bogus RREAD count (%d > %d)\n", received, rsize);
1584 		received = rsize;
1585 	}
1586 
1587 	p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1588 
1589 	if (non_zc) {
1590 		int n = copy_to_iter(dataptr, received, to);
1591 
1592 		if (n != received) {
1593 			*err = -EFAULT;
1594 			p9_req_put(clnt, req);
1595 			return n;
1596 		}
1597 	} else {
1598 		iov_iter_revert(to, count - received - iov_iter_count(to));
1599 	}
1600 	p9_req_put(clnt, req);
1601 	return received;
1602 }
1603 EXPORT_SYMBOL(p9_client_read_once);
1604 
1605 int
1606 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1607 {
1608 	struct p9_client *clnt = fid->clnt;
1609 	struct p9_req_t *req;
1610 	int total = 0;
1611 	*err = 0;
1612 
1613 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n",
1614 		 fid->fid, offset, iov_iter_count(from));
1615 
1616 	while (iov_iter_count(from)) {
1617 		int count = iov_iter_count(from);
1618 		int rsize = fid->iounit;
1619 		int written;
1620 
1621 		if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1622 			rsize = clnt->msize - P9_IOHDRSZ;
1623 
1624 		if (count < rsize)
1625 			rsize = count;
1626 
1627 		/* Don't bother zerocopy for small IO (< 1024) */
1628 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1629 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1630 					       rsize, P9_ZC_HDR_SZ, "dqd",
1631 					       fid->fid, offset, rsize);
1632 		} else {
1633 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1634 					    offset, rsize, from);
1635 		}
1636 		if (IS_ERR(req)) {
1637 			iov_iter_revert(from, count - iov_iter_count(from));
1638 			*err = PTR_ERR(req);
1639 			break;
1640 		}
1641 
1642 		*err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &written);
1643 		if (*err) {
1644 			iov_iter_revert(from, count - iov_iter_count(from));
1645 			trace_9p_protocol_dump(clnt, &req->rc);
1646 			p9_req_put(clnt, req);
1647 			break;
1648 		}
1649 		if (rsize < written) {
1650 			pr_err("bogus RWRITE count (%d > %d)\n", written, rsize);
1651 			written = rsize;
1652 		}
1653 
1654 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1655 
1656 		p9_req_put(clnt, req);
1657 		iov_iter_revert(from, count - written - iov_iter_count(from));
1658 		total += written;
1659 		offset += written;
1660 	}
1661 	return total;
1662 }
1663 EXPORT_SYMBOL(p9_client_write);
1664 
1665 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1666 {
1667 	int err;
1668 	struct p9_client *clnt;
1669 	struct p9_wstat *ret;
1670 	struct p9_req_t *req;
1671 	u16 ignored;
1672 
1673 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1674 
1675 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1676 	if (!ret)
1677 		return ERR_PTR(-ENOMEM);
1678 
1679 	err = 0;
1680 	clnt = fid->clnt;
1681 
1682 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1683 	if (IS_ERR(req)) {
1684 		err = PTR_ERR(req);
1685 		goto error;
1686 	}
1687 
1688 	err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
1689 	if (err) {
1690 		trace_9p_protocol_dump(clnt, &req->rc);
1691 		p9_req_put(clnt, req);
1692 		goto error;
1693 	}
1694 
1695 	p9_debug(P9_DEBUG_9P,
1696 		 "<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1697 		 "<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1698 		 "<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1699 		 "<<<    uid=%d gid=%d n_muid=%d\n",
1700 		 ret->size, ret->type, ret->dev, ret->qid.type, ret->qid.path,
1701 		 ret->qid.version, ret->mode,
1702 		 ret->atime, ret->mtime, ret->length,
1703 		 ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1704 		 from_kuid(&init_user_ns, ret->n_uid),
1705 		 from_kgid(&init_user_ns, ret->n_gid),
1706 		 from_kuid(&init_user_ns, ret->n_muid));
1707 
1708 	p9_req_put(clnt, req);
1709 	return ret;
1710 
1711 error:
1712 	kfree(ret);
1713 	return ERR_PTR(err);
1714 }
1715 EXPORT_SYMBOL(p9_client_stat);
1716 
1717 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1718 					    u64 request_mask)
1719 {
1720 	int err;
1721 	struct p9_client *clnt;
1722 	struct p9_stat_dotl *ret;
1723 	struct p9_req_t *req;
1724 
1725 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1726 		 fid->fid, request_mask);
1727 
1728 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1729 	if (!ret)
1730 		return ERR_PTR(-ENOMEM);
1731 
1732 	err = 0;
1733 	clnt = fid->clnt;
1734 
1735 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1736 	if (IS_ERR(req)) {
1737 		err = PTR_ERR(req);
1738 		goto error;
1739 	}
1740 
1741 	err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
1742 	if (err) {
1743 		trace_9p_protocol_dump(clnt, &req->rc);
1744 		p9_req_put(clnt, req);
1745 		goto error;
1746 	}
1747 
1748 	p9_debug(P9_DEBUG_9P, "<<< RGETATTR st_result_mask=%lld\n"
1749 		 "<<< qid=%x.%llx.%x\n"
1750 		 "<<< st_mode=%8.8x st_nlink=%llu\n"
1751 		 "<<< st_uid=%d st_gid=%d\n"
1752 		 "<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1753 		 "<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1754 		 "<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1755 		 "<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1756 		 "<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1757 		 "<<< st_gen=%lld st_data_version=%lld\n",
1758 		 ret->st_result_mask,
1759 		 ret->qid.type, ret->qid.path, ret->qid.version,
1760 		 ret->st_mode, ret->st_nlink,
1761 		 from_kuid(&init_user_ns, ret->st_uid),
1762 		 from_kgid(&init_user_ns, ret->st_gid),
1763 		 ret->st_rdev, ret->st_size, ret->st_blksize, ret->st_blocks,
1764 		 ret->st_atime_sec, ret->st_atime_nsec,
1765 		 ret->st_mtime_sec, ret->st_mtime_nsec,
1766 		 ret->st_ctime_sec, ret->st_ctime_nsec,
1767 		 ret->st_btime_sec, ret->st_btime_nsec,
1768 		 ret->st_gen, ret->st_data_version);
1769 
1770 	p9_req_put(clnt, req);
1771 	return ret;
1772 
1773 error:
1774 	kfree(ret);
1775 	return ERR_PTR(err);
1776 }
1777 EXPORT_SYMBOL(p9_client_getattr_dotl);
1778 
1779 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1780 {
1781 	int ret;
1782 
1783 	/* NOTE: size shouldn't include its own length */
1784 	/* size[2] type[2] dev[4] qid[13] */
1785 	/* mode[4] atime[4] mtime[4] length[8]*/
1786 	/* name[s] uid[s] gid[s] muid[s] */
1787 	ret = 2 + 4 + 13 + 4 + 4 + 4 + 8 + 2 + 2 + 2 + 2;
1788 
1789 	if (wst->name)
1790 		ret += strlen(wst->name);
1791 	if (wst->uid)
1792 		ret += strlen(wst->uid);
1793 	if (wst->gid)
1794 		ret += strlen(wst->gid);
1795 	if (wst->muid)
1796 		ret += strlen(wst->muid);
1797 
1798 	if (proto_version == p9_proto_2000u ||
1799 	    proto_version == p9_proto_2000L) {
1800 		/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1801 		ret += 2 + 4 + 4 + 4;
1802 		if (wst->extension)
1803 			ret += strlen(wst->extension);
1804 	}
1805 
1806 	return ret;
1807 }
1808 
1809 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1810 {
1811 	int err;
1812 	struct p9_req_t *req;
1813 	struct p9_client *clnt;
1814 
1815 	err = 0;
1816 	clnt = fid->clnt;
1817 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1818 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n",
1819 		 fid->fid);
1820 	p9_debug(P9_DEBUG_9P,
1821 		 "     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1822 		 "     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1823 		 "     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1824 		 "     uid=%d gid=%d n_muid=%d\n",
1825 		 wst->size, wst->type, wst->dev, wst->qid.type,
1826 		 wst->qid.path, wst->qid.version,
1827 		 wst->mode, wst->atime, wst->mtime, wst->length,
1828 		 wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1829 		 from_kuid(&init_user_ns, wst->n_uid),
1830 		 from_kgid(&init_user_ns, wst->n_gid),
1831 		 from_kuid(&init_user_ns, wst->n_muid));
1832 
1833 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS",
1834 			    fid->fid, wst->size + 2, wst);
1835 	if (IS_ERR(req)) {
1836 		err = PTR_ERR(req);
1837 		goto error;
1838 	}
1839 
1840 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1841 
1842 	p9_req_put(clnt, req);
1843 error:
1844 	return err;
1845 }
1846 EXPORT_SYMBOL(p9_client_wstat);
1847 
1848 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1849 {
1850 	int err;
1851 	struct p9_req_t *req;
1852 	struct p9_client *clnt;
1853 
1854 	err = 0;
1855 	clnt = fid->clnt;
1856 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1857 	p9_debug(P9_DEBUG_9P, "    valid=%x mode=%x uid=%d gid=%d size=%lld\n",
1858 		 p9attr->valid, p9attr->mode,
1859 		 from_kuid(&init_user_ns, p9attr->uid),
1860 		 from_kgid(&init_user_ns, p9attr->gid),
1861 		 p9attr->size);
1862 	p9_debug(P9_DEBUG_9P, "    atime_sec=%lld atime_nsec=%lld\n",
1863 		 p9attr->atime_sec, p9attr->atime_nsec);
1864 	p9_debug(P9_DEBUG_9P, "    mtime_sec=%lld mtime_nsec=%lld\n",
1865 		 p9attr->mtime_sec, p9attr->mtime_nsec);
1866 
1867 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1868 
1869 	if (IS_ERR(req)) {
1870 		err = PTR_ERR(req);
1871 		goto error;
1872 	}
1873 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1874 	p9_req_put(clnt, req);
1875 error:
1876 	return err;
1877 }
1878 EXPORT_SYMBOL(p9_client_setattr);
1879 
1880 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1881 {
1882 	int err;
1883 	struct p9_req_t *req;
1884 	struct p9_client *clnt;
1885 
1886 	err = 0;
1887 	clnt = fid->clnt;
1888 
1889 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1890 
1891 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1892 	if (IS_ERR(req)) {
1893 		err = PTR_ERR(req);
1894 		goto error;
1895 	}
1896 
1897 	err = p9pdu_readf(&req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1898 			  &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1899 			  &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1900 	if (err) {
1901 		trace_9p_protocol_dump(clnt, &req->rc);
1902 		p9_req_put(clnt, req);
1903 		goto error;
1904 	}
1905 
1906 	p9_debug(P9_DEBUG_9P,
1907 		 "<<< RSTATFS fid %d type 0x%x bsize %u blocks %llu bfree %llu bavail %llu files %llu ffree %llu fsid %llu namelen %u\n",
1908 		 fid->fid, sb->type, sb->bsize, sb->blocks, sb->bfree,
1909 		 sb->bavail, sb->files, sb->ffree, sb->fsid, sb->namelen);
1910 
1911 	p9_req_put(clnt, req);
1912 error:
1913 	return err;
1914 }
1915 EXPORT_SYMBOL(p9_client_statfs);
1916 
1917 int p9_client_rename(struct p9_fid *fid,
1918 		     struct p9_fid *newdirfid, const char *name)
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, ">>> TRENAME fid %d newdirfid %d name %s\n",
1928 		 fid->fid, newdirfid->fid, name);
1929 
1930 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1931 			    newdirfid->fid, name);
1932 	if (IS_ERR(req)) {
1933 		err = PTR_ERR(req);
1934 		goto error;
1935 	}
1936 
1937 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1938 
1939 	p9_req_put(clnt, req);
1940 error:
1941 	return err;
1942 }
1943 EXPORT_SYMBOL(p9_client_rename);
1944 
1945 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
1946 		       struct p9_fid *newdirfid, const char *new_name)
1947 {
1948 	int err;
1949 	struct p9_req_t *req;
1950 	struct p9_client *clnt;
1951 
1952 	err = 0;
1953 	clnt = olddirfid->clnt;
1954 
1955 	p9_debug(P9_DEBUG_9P,
1956 		 ">>> TRENAMEAT olddirfid %d old name %s newdirfid %d new name %s\n",
1957 		 olddirfid->fid, old_name, newdirfid->fid, new_name);
1958 
1959 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
1960 			    old_name, newdirfid->fid, new_name);
1961 	if (IS_ERR(req)) {
1962 		err = PTR_ERR(req);
1963 		goto error;
1964 	}
1965 
1966 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
1967 		 newdirfid->fid, new_name);
1968 
1969 	p9_req_put(clnt, req);
1970 error:
1971 	return err;
1972 }
1973 EXPORT_SYMBOL(p9_client_renameat);
1974 
1975 /* An xattrwalk without @attr_name gives the fid for the lisxattr namespace
1976  */
1977 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
1978 				   const char *attr_name, u64 *attr_size)
1979 {
1980 	int err;
1981 	struct p9_req_t *req;
1982 	struct p9_client *clnt;
1983 	struct p9_fid *attr_fid;
1984 
1985 	err = 0;
1986 	clnt = file_fid->clnt;
1987 	attr_fid = p9_fid_create(clnt);
1988 	if (!attr_fid) {
1989 		err = -ENOMEM;
1990 		goto error;
1991 	}
1992 	p9_debug(P9_DEBUG_9P,
1993 		 ">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
1994 		 file_fid->fid, attr_fid->fid, attr_name);
1995 
1996 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
1997 			    file_fid->fid, attr_fid->fid, attr_name);
1998 	if (IS_ERR(req)) {
1999 		err = PTR_ERR(req);
2000 		goto error;
2001 	}
2002 	err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
2003 	if (err) {
2004 		trace_9p_protocol_dump(clnt, &req->rc);
2005 		p9_req_put(clnt, req);
2006 		goto clunk_fid;
2007 	}
2008 	p9_req_put(clnt, req);
2009 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
2010 		 attr_fid->fid, *attr_size);
2011 	return attr_fid;
2012 clunk_fid:
2013 	p9_fid_put(attr_fid);
2014 	attr_fid = NULL;
2015 error:
2016 	if (attr_fid && attr_fid != file_fid)
2017 		p9_fid_destroy(attr_fid);
2018 
2019 	return ERR_PTR(err);
2020 }
2021 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
2022 
2023 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
2024 			  u64 attr_size, int flags)
2025 {
2026 	int err;
2027 	struct p9_req_t *req;
2028 	struct p9_client *clnt;
2029 
2030 	p9_debug(P9_DEBUG_9P,
2031 		 ">>> TXATTRCREATE fid %d name  %s size %llu flag %d\n",
2032 		 fid->fid, name, attr_size, flags);
2033 	err = 0;
2034 	clnt = fid->clnt;
2035 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
2036 			    fid->fid, name, attr_size, flags);
2037 	if (IS_ERR(req)) {
2038 		err = PTR_ERR(req);
2039 		goto error;
2040 	}
2041 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
2042 	p9_req_put(clnt, req);
2043 error:
2044 	return err;
2045 }
2046 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
2047 
2048 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
2049 {
2050 	int err, rsize, non_zc = 0;
2051 	struct p9_client *clnt;
2052 	struct p9_req_t *req;
2053 	char *dataptr;
2054 	struct kvec kv = {.iov_base = data, .iov_len = count};
2055 	struct iov_iter to;
2056 
2057 	iov_iter_kvec(&to, ITER_DEST, &kv, 1, count);
2058 
2059 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
2060 		 fid->fid, offset, count);
2061 
2062 	err = 0;
2063 	clnt = fid->clnt;
2064 
2065 	rsize = fid->iounit;
2066 	if (!rsize || rsize > clnt->msize - P9_READDIRHDRSZ)
2067 		rsize = clnt->msize - P9_READDIRHDRSZ;
2068 
2069 	if (count < rsize)
2070 		rsize = count;
2071 
2072 	/* Don't bother zerocopy for small IO (< 1024) */
2073 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2074 		/* response header len is 11
2075 		 * PDU Header(7) + IO Size (4)
2076 		 */
2077 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2078 				       11, "dqd", fid->fid, offset, rsize);
2079 	} else {
2080 		non_zc = 1;
2081 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2082 				    offset, rsize);
2083 	}
2084 	if (IS_ERR(req)) {
2085 		err = PTR_ERR(req);
2086 		goto error;
2087 	}
2088 
2089 	err = p9pdu_readf(&req->rc, clnt->proto_version, "D", &count, &dataptr);
2090 	if (err) {
2091 		trace_9p_protocol_dump(clnt, &req->rc);
2092 		goto free_and_error;
2093 	}
2094 	if (rsize < count) {
2095 		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
2096 		count = rsize;
2097 	}
2098 
2099 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
2100 
2101 	if (non_zc)
2102 		memmove(data, dataptr, count);
2103 
2104 	p9_req_put(clnt, req);
2105 	return count;
2106 
2107 free_and_error:
2108 	p9_req_put(clnt, req);
2109 error:
2110 	return err;
2111 }
2112 EXPORT_SYMBOL(p9_client_readdir);
2113 
2114 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2115 			 dev_t rdev, kgid_t gid, struct p9_qid *qid)
2116 {
2117 	int err;
2118 	struct p9_client *clnt;
2119 	struct p9_req_t *req;
2120 
2121 	err = 0;
2122 	clnt = fid->clnt;
2123 	p9_debug(P9_DEBUG_9P,
2124 		 ">>> TMKNOD fid %d name %s mode %d major %d minor %d\n",
2125 		 fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2126 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2127 			    MAJOR(rdev), MINOR(rdev), gid);
2128 	if (IS_ERR(req))
2129 		return PTR_ERR(req);
2130 
2131 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2132 	if (err) {
2133 		trace_9p_protocol_dump(clnt, &req->rc);
2134 		goto error;
2135 	}
2136 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n",
2137 		 qid->type, qid->path, qid->version);
2138 
2139 error:
2140 	p9_req_put(clnt, req);
2141 	return err;
2142 }
2143 EXPORT_SYMBOL(p9_client_mknod_dotl);
2144 
2145 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2146 			 kgid_t gid, struct p9_qid *qid)
2147 {
2148 	int err;
2149 	struct p9_client *clnt;
2150 	struct p9_req_t *req;
2151 
2152 	err = 0;
2153 	clnt = fid->clnt;
2154 	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
2155 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
2156 	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg",
2157 			    fid->fid, name, mode, gid);
2158 	if (IS_ERR(req))
2159 		return PTR_ERR(req);
2160 
2161 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2162 	if (err) {
2163 		trace_9p_protocol_dump(clnt, &req->rc);
2164 		goto error;
2165 	}
2166 	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
2167 		 qid->path, qid->version);
2168 
2169 error:
2170 	p9_req_put(clnt, req);
2171 	return err;
2172 }
2173 EXPORT_SYMBOL(p9_client_mkdir_dotl);
2174 
2175 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
2176 {
2177 	int err;
2178 	struct p9_client *clnt;
2179 	struct p9_req_t *req;
2180 
2181 	err = 0;
2182 	clnt = fid->clnt;
2183 	p9_debug(P9_DEBUG_9P,
2184 		 ">>> TLOCK fid %d type %i flags %d start %lld length %lld proc_id %d client_id %s\n",
2185 		 fid->fid, flock->type, flock->flags, flock->start,
2186 		 flock->length, flock->proc_id, flock->client_id);
2187 
2188 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2189 			    flock->flags, flock->start, flock->length,
2190 			    flock->proc_id, flock->client_id);
2191 
2192 	if (IS_ERR(req))
2193 		return PTR_ERR(req);
2194 
2195 	err = p9pdu_readf(&req->rc, clnt->proto_version, "b", status);
2196 	if (err) {
2197 		trace_9p_protocol_dump(clnt, &req->rc);
2198 		goto error;
2199 	}
2200 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2201 error:
2202 	p9_req_put(clnt, req);
2203 	return err;
2204 }
2205 EXPORT_SYMBOL(p9_client_lock_dotl);
2206 
2207 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2208 {
2209 	int err;
2210 	struct p9_client *clnt;
2211 	struct p9_req_t *req;
2212 
2213 	err = 0;
2214 	clnt = fid->clnt;
2215 	p9_debug(P9_DEBUG_9P,
2216 		 ">>> TGETLOCK fid %d, type %i start %lld length %lld proc_id %d client_id %s\n",
2217 		 fid->fid, glock->type, glock->start, glock->length,
2218 		 glock->proc_id, glock->client_id);
2219 
2220 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,
2221 			    glock->type, glock->start, glock->length,
2222 			    glock->proc_id, glock->client_id);
2223 
2224 	if (IS_ERR(req))
2225 		return PTR_ERR(req);
2226 
2227 	err = p9pdu_readf(&req->rc, clnt->proto_version, "bqqds", &glock->type,
2228 			  &glock->start, &glock->length, &glock->proc_id,
2229 			  &glock->client_id);
2230 	if (err) {
2231 		trace_9p_protocol_dump(clnt, &req->rc);
2232 		goto error;
2233 	}
2234 	p9_debug(P9_DEBUG_9P,
2235 		 "<<< RGETLOCK type %i start %lld length %lld proc_id %d client_id %s\n",
2236 		 glock->type, glock->start, glock->length,
2237 		 glock->proc_id, glock->client_id);
2238 error:
2239 	p9_req_put(clnt, req);
2240 	return err;
2241 }
2242 EXPORT_SYMBOL(p9_client_getlock_dotl);
2243 
2244 int p9_client_readlink(struct p9_fid *fid, char **target)
2245 {
2246 	int err;
2247 	struct p9_client *clnt;
2248 	struct p9_req_t *req;
2249 
2250 	err = 0;
2251 	clnt = fid->clnt;
2252 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2253 
2254 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2255 	if (IS_ERR(req))
2256 		return PTR_ERR(req);
2257 
2258 	err = p9pdu_readf(&req->rc, clnt->proto_version, "s", target);
2259 	if (err) {
2260 		trace_9p_protocol_dump(clnt, &req->rc);
2261 		goto error;
2262 	}
2263 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2264 error:
2265 	p9_req_put(clnt, req);
2266 	return err;
2267 }
2268 EXPORT_SYMBOL(p9_client_readlink);
2269 
2270 int __init p9_client_init(void)
2271 {
2272 	p9_req_cache = KMEM_CACHE(p9_req_t, SLAB_TYPESAFE_BY_RCU);
2273 	return p9_req_cache ? 0 : -ENOMEM;
2274 }
2275 
2276 void __exit p9_client_exit(void)
2277 {
2278 	kmem_cache_destroy(p9_req_cache);
2279 }
2280