xref: /openbmc/linux/net/9p/client.c (revision 98a52692)
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 /* DEFAULT MSIZE = 32 pages worth of payload + P9_HDRSZ +
32  * room for write (16 extra) or read (11 extra) operands.
33  */
34 
35 #define DEFAULT_MSIZE ((128 * 1024) + P9_IOHDRSZ)
36 
37 /* Client Option Parsing (code inspired by NFS code)
38  *  - a little lazy - parse all client options
39  */
40 
41 enum {
42 	Opt_msize,
43 	Opt_trans,
44 	Opt_legacy,
45 	Opt_version,
46 	Opt_err,
47 };
48 
49 static const match_table_t tokens = {
50 	{Opt_msize, "msize=%u"},
51 	{Opt_legacy, "noextend"},
52 	{Opt_trans, "trans=%s"},
53 	{Opt_version, "version=%s"},
54 	{Opt_err, NULL},
55 };
56 
57 inline int p9_is_proto_dotl(struct p9_client *clnt)
58 {
59 	return clnt->proto_version == p9_proto_2000L;
60 }
61 EXPORT_SYMBOL(p9_is_proto_dotl);
62 
63 inline int p9_is_proto_dotu(struct p9_client *clnt)
64 {
65 	return clnt->proto_version == p9_proto_2000u;
66 }
67 EXPORT_SYMBOL(p9_is_proto_dotu);
68 
69 int p9_show_client_options(struct seq_file *m, struct p9_client *clnt)
70 {
71 	if (clnt->msize != DEFAULT_MSIZE)
72 		seq_printf(m, ",msize=%u", clnt->msize);
73 	seq_printf(m, ",trans=%s", clnt->trans_mod->name);
74 
75 	switch (clnt->proto_version) {
76 	case p9_proto_legacy:
77 		seq_puts(m, ",noextend");
78 		break;
79 	case p9_proto_2000u:
80 		seq_puts(m, ",version=9p2000.u");
81 		break;
82 	case p9_proto_2000L:
83 		/* Default */
84 		break;
85 	}
86 
87 	if (clnt->trans_mod->show_options)
88 		return clnt->trans_mod->show_options(m, clnt);
89 	return 0;
90 }
91 EXPORT_SYMBOL(p9_show_client_options);
92 
93 /* Some error codes are taken directly from the server replies,
94  * make sure they are valid.
95  */
96 static int safe_errno(int err)
97 {
98 	if (err > 0 || err < -MAX_ERRNO) {
99 		p9_debug(P9_DEBUG_ERROR, "Invalid error code %d\n", err);
100 		return -EPROTO;
101 	}
102 	return err;
103 }
104 
105 /* Interpret mount option for protocol version */
106 static int get_protocol_version(char *s)
107 {
108 	int version = -EINVAL;
109 
110 	if (!strcmp(s, "9p2000")) {
111 		version = p9_proto_legacy;
112 		p9_debug(P9_DEBUG_9P, "Protocol version: Legacy\n");
113 	} else if (!strcmp(s, "9p2000.u")) {
114 		version = p9_proto_2000u;
115 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.u\n");
116 	} else if (!strcmp(s, "9p2000.L")) {
117 		version = p9_proto_2000L;
118 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.L\n");
119 	} else {
120 		pr_info("Unknown protocol version %s\n", s);
121 	}
122 
123 	return version;
124 }
125 
126 /**
127  * parse_opts - parse mount options into client structure
128  * @opts: options string passed from mount
129  * @clnt: existing v9fs client information
130  *
131  * Return 0 upon success, -ERRNO upon failure
132  */
133 
134 static int parse_opts(char *opts, struct p9_client *clnt)
135 {
136 	char *options, *tmp_options;
137 	char *p;
138 	substring_t args[MAX_OPT_ARGS];
139 	int option;
140 	char *s;
141 	int ret = 0;
142 
143 	clnt->proto_version = p9_proto_2000L;
144 	clnt->msize = DEFAULT_MSIZE;
145 
146 	if (!opts)
147 		return 0;
148 
149 	tmp_options = kstrdup(opts, GFP_KERNEL);
150 	if (!tmp_options)
151 		return -ENOMEM;
152 	options = tmp_options;
153 
154 	while ((p = strsep(&options, ",")) != NULL) {
155 		int token, r;
156 
157 		if (!*p)
158 			continue;
159 		token = match_token(p, tokens, args);
160 		switch (token) {
161 		case Opt_msize:
162 			r = match_int(&args[0], &option);
163 			if (r < 0) {
164 				p9_debug(P9_DEBUG_ERROR,
165 					 "integer field, but no integer?\n");
166 				ret = r;
167 				continue;
168 			}
169 			if (option < 4096) {
170 				p9_debug(P9_DEBUG_ERROR,
171 					 "msize should be at least 4k\n");
172 				ret = -EINVAL;
173 				continue;
174 			}
175 			clnt->msize = option;
176 			break;
177 		case Opt_trans:
178 			s = match_strdup(&args[0]);
179 			if (!s) {
180 				ret = -ENOMEM;
181 				p9_debug(P9_DEBUG_ERROR,
182 					 "problem allocating copy of trans arg\n");
183 				goto free_and_return;
184 			}
185 
186 			v9fs_put_trans(clnt->trans_mod);
187 			clnt->trans_mod = v9fs_get_trans_by_name(s);
188 			if (!clnt->trans_mod) {
189 				pr_info("Could not find request transport: %s\n",
190 					s);
191 				ret = -EINVAL;
192 			}
193 			kfree(s);
194 			break;
195 		case Opt_legacy:
196 			clnt->proto_version = p9_proto_legacy;
197 			break;
198 		case Opt_version:
199 			s = match_strdup(&args[0]);
200 			if (!s) {
201 				ret = -ENOMEM;
202 				p9_debug(P9_DEBUG_ERROR,
203 					 "problem allocating copy of version arg\n");
204 				goto free_and_return;
205 			}
206 			r = get_protocol_version(s);
207 			if (r < 0)
208 				ret = r;
209 			else
210 				clnt->proto_version = r;
211 			kfree(s);
212 			break;
213 		default:
214 			continue;
215 		}
216 	}
217 
218 free_and_return:
219 	if (ret)
220 		v9fs_put_trans(clnt->trans_mod);
221 	kfree(tmp_options);
222 	return ret;
223 }
224 
225 static int p9_fcall_init(struct p9_client *c, struct p9_fcall *fc,
226 			 int alloc_msize)
227 {
228 	if (likely(c->fcall_cache) && alloc_msize == c->msize) {
229 		fc->sdata = kmem_cache_alloc(c->fcall_cache, GFP_NOFS);
230 		fc->cache = c->fcall_cache;
231 	} else {
232 		fc->sdata = kmalloc(alloc_msize, GFP_NOFS);
233 		fc->cache = NULL;
234 	}
235 	if (!fc->sdata)
236 		return -ENOMEM;
237 	fc->capacity = alloc_msize;
238 	return 0;
239 }
240 
241 void p9_fcall_fini(struct p9_fcall *fc)
242 {
243 	/* sdata can be NULL for interrupted requests in trans_rdma,
244 	 * and kmem_cache_free does not do NULL-check for us
245 	 */
246 	if (unlikely(!fc->sdata))
247 		return;
248 
249 	if (fc->cache)
250 		kmem_cache_free(fc->cache, fc->sdata);
251 	else
252 		kfree(fc->sdata);
253 }
254 EXPORT_SYMBOL(p9_fcall_fini);
255 
256 static struct kmem_cache *p9_req_cache;
257 
258 /**
259  * p9_tag_alloc - Allocate a new request.
260  * @c: Client session.
261  * @type: Transaction type.
262  * @t_size: Buffer size for holding this request
263  * (automatic calculation by format template if 0).
264  * @r_size: Buffer size for holding server's reply on this request
265  * (automatic calculation by format template if 0).
266  * @fmt: Format template for assembling 9p request message
267  * (see p9pdu_vwritef).
268  * @ap: Variable arguments to be fed to passed format template
269  * (see p9pdu_vwritef).
270  *
271  * Context: Process context.
272  * Return: Pointer to new request.
273  */
274 static struct p9_req_t *
275 p9_tag_alloc(struct p9_client *c, int8_t type, uint t_size, uint r_size,
276 	      const char *fmt, va_list ap)
277 {
278 	struct p9_req_t *req = kmem_cache_alloc(p9_req_cache, GFP_NOFS);
279 	int alloc_tsize;
280 	int alloc_rsize;
281 	int tag;
282 	va_list apc;
283 
284 	va_copy(apc, ap);
285 	alloc_tsize = min_t(size_t, c->msize,
286 			    t_size ?: p9_msg_buf_size(c, type, fmt, apc));
287 	va_end(apc);
288 
289 	alloc_rsize = min_t(size_t, c->msize,
290 			    r_size ?: p9_msg_buf_size(c, type + 1, fmt, ap));
291 
292 	if (!req)
293 		return ERR_PTR(-ENOMEM);
294 
295 	if (p9_fcall_init(c, &req->tc, alloc_tsize))
296 		goto free_req;
297 	if (p9_fcall_init(c, &req->rc, alloc_rsize))
298 		goto free;
299 
300 	p9pdu_reset(&req->tc);
301 	p9pdu_reset(&req->rc);
302 	req->t_err = 0;
303 	req->status = REQ_STATUS_ALLOC;
304 	/* refcount needs to be set to 0 before inserting into the idr
305 	 * so p9_tag_lookup does not accept a request that is not fully
306 	 * initialized. refcount_set to 2 below will mark request ready.
307 	 */
308 	refcount_set(&req->refcount, 0);
309 	init_waitqueue_head(&req->wq);
310 	INIT_LIST_HEAD(&req->req_list);
311 
312 	idr_preload(GFP_NOFS);
313 	spin_lock_irq(&c->lock);
314 	if (type == P9_TVERSION)
315 		tag = idr_alloc(&c->reqs, req, P9_NOTAG, P9_NOTAG + 1,
316 				GFP_NOWAIT);
317 	else
318 		tag = idr_alloc(&c->reqs, req, 0, P9_NOTAG, GFP_NOWAIT);
319 	req->tc.tag = tag;
320 	spin_unlock_irq(&c->lock);
321 	idr_preload_end();
322 	if (tag < 0)
323 		goto free;
324 
325 	/* Init ref to two because in the general case there is one ref
326 	 * that is put asynchronously by a writer thread, one ref
327 	 * temporarily given by p9_tag_lookup and put by p9_client_cb
328 	 * in the recv thread, and one ref put by p9_req_put in the
329 	 * main thread. The only exception is virtio that does not use
330 	 * p9_tag_lookup but does not have a writer thread either
331 	 * (the write happens synchronously in the request/zc_request
332 	 * callback), so p9_client_cb eats the second ref there
333 	 * as the pointer is duplicated directly by virtqueue_add_sgs()
334 	 */
335 	refcount_set(&req->refcount, 2);
336 
337 	return req;
338 
339 free:
340 	p9_fcall_fini(&req->tc);
341 	p9_fcall_fini(&req->rc);
342 free_req:
343 	kmem_cache_free(p9_req_cache, req);
344 	return ERR_PTR(-ENOMEM);
345 }
346 
347 /**
348  * p9_tag_lookup - Look up a request by tag.
349  * @c: Client session.
350  * @tag: Transaction ID.
351  *
352  * Context: Any context.
353  * Return: A request, or %NULL if there is no request with that tag.
354  */
355 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
356 {
357 	struct p9_req_t *req;
358 
359 	rcu_read_lock();
360 again:
361 	req = idr_find(&c->reqs, tag);
362 	if (req) {
363 		/* We have to be careful with the req found under rcu_read_lock
364 		 * Thanks to SLAB_TYPESAFE_BY_RCU we can safely try to get the
365 		 * ref again without corrupting other data, then check again
366 		 * that the tag matches once we have the ref
367 		 */
368 		if (!p9_req_try_get(req))
369 			goto again;
370 		if (req->tc.tag != tag) {
371 			p9_req_put(c, req);
372 			goto again;
373 		}
374 	}
375 	rcu_read_unlock();
376 
377 	return req;
378 }
379 EXPORT_SYMBOL(p9_tag_lookup);
380 
381 /**
382  * p9_tag_remove - Remove a tag.
383  * @c: Client session.
384  * @r: Request of reference.
385  *
386  * Context: Any context.
387  */
388 static void p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
389 {
390 	unsigned long flags;
391 	u16 tag = r->tc.tag;
392 
393 	p9_debug(P9_DEBUG_MUX, "freeing clnt %p req %p tag: %d\n", c, r, tag);
394 	spin_lock_irqsave(&c->lock, flags);
395 	idr_remove(&c->reqs, tag);
396 	spin_unlock_irqrestore(&c->lock, flags);
397 }
398 
399 int p9_req_put(struct p9_client *c, struct p9_req_t *r)
400 {
401 	if (refcount_dec_and_test(&r->refcount)) {
402 		p9_tag_remove(c, r);
403 
404 		p9_fcall_fini(&r->tc);
405 		p9_fcall_fini(&r->rc);
406 		kmem_cache_free(p9_req_cache, r);
407 		return 1;
408 	}
409 	return 0;
410 }
411 EXPORT_SYMBOL(p9_req_put);
412 
413 /**
414  * p9_tag_cleanup - cleans up tags structure and reclaims resources
415  * @c:  v9fs client struct
416  *
417  * This frees resources associated with the tags structure
418  *
419  */
420 static void p9_tag_cleanup(struct p9_client *c)
421 {
422 	struct p9_req_t *req;
423 	int id;
424 
425 	rcu_read_lock();
426 	idr_for_each_entry(&c->reqs, req, id) {
427 		pr_info("Tag %d still in use\n", id);
428 		if (p9_req_put(c, req) == 0)
429 			pr_warn("Packet with tag %d has still references",
430 				req->tc.tag);
431 	}
432 	rcu_read_unlock();
433 }
434 
435 /**
436  * p9_client_cb - call back from transport to client
437  * @c: client state
438  * @req: request received
439  * @status: request status, one of REQ_STATUS_*
440  *
441  */
442 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
443 {
444 	p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc.tag);
445 
446 	/* This barrier is needed to make sure any change made to req before
447 	 * the status change is visible to another thread
448 	 */
449 	smp_wmb();
450 	WRITE_ONCE(req->status, status);
451 
452 	wake_up(&req->wq);
453 	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
454 	p9_req_put(c, req);
455 }
456 EXPORT_SYMBOL(p9_client_cb);
457 
458 /**
459  * p9_parse_header - parse header arguments out of a packet
460  * @pdu: packet to parse
461  * @size: size of packet
462  * @type: type of request
463  * @tag: tag of packet
464  * @rewind: set if we need to rewind offset afterwards
465  */
466 
467 int
468 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type,
469 		int16_t *tag, int rewind)
470 {
471 	s8 r_type;
472 	s16 r_tag;
473 	s32 r_size;
474 	int offset = pdu->offset;
475 	int err;
476 
477 	pdu->offset = 0;
478 
479 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
480 	if (err)
481 		goto rewind_and_exit;
482 
483 	if (type)
484 		*type = r_type;
485 	if (tag)
486 		*tag = r_tag;
487 	if (size)
488 		*size = r_size;
489 
490 	if (pdu->size != r_size || r_size < 7) {
491 		err = -EINVAL;
492 		goto rewind_and_exit;
493 	}
494 
495 	pdu->id = r_type;
496 	pdu->tag = r_tag;
497 
498 	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
499 		 pdu->size, pdu->id, pdu->tag);
500 
501 rewind_and_exit:
502 	if (rewind)
503 		pdu->offset = offset;
504 	return err;
505 }
506 EXPORT_SYMBOL(p9_parse_header);
507 
508 /**
509  * p9_check_errors - check 9p packet for error return and process it
510  * @c: current client instance
511  * @req: request to parse and check for error conditions
512  *
513  * returns error code if one is discovered, otherwise returns 0
514  *
515  * this will have to be more complicated if we have multiple
516  * error packet types
517  */
518 
519 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
520 {
521 	s8 type;
522 	int err;
523 	int ecode;
524 
525 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
526 	if (req->rc.size > req->rc.capacity && !req->rc.zc) {
527 		pr_err("requested packet size too big: %d does not fit %zu (type=%d)\n",
528 		       req->rc.size, req->rc.capacity, req->rc.id);
529 		return -EIO;
530 	}
531 	/* dump the response from server
532 	 * This should be after check errors which poplulate pdu_fcall.
533 	 */
534 	trace_9p_protocol_dump(c, &req->rc);
535 	if (err) {
536 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
537 		return err;
538 	}
539 	if (type != P9_RERROR && type != P9_RLERROR)
540 		return 0;
541 
542 	if (!p9_is_proto_dotl(c)) {
543 		char *ename = NULL;
544 
545 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
546 				  &ename, &ecode);
547 		if (err) {
548 			kfree(ename);
549 			goto out_err;
550 		}
551 
552 		if (p9_is_proto_dotu(c) && ecode < 512)
553 			err = -ecode;
554 
555 		if (!err) {
556 			err = p9_errstr2errno(ename, strlen(ename));
557 
558 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
559 				 -ecode, ename);
560 		}
561 		kfree(ename);
562 	} else {
563 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
564 		if (err)
565 			goto out_err;
566 		err = -ecode;
567 
568 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
569 	}
570 
571 	return err;
572 
573 out_err:
574 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
575 
576 	return err;
577 }
578 
579 static struct p9_req_t *
580 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
581 
582 /**
583  * p9_client_flush - flush (cancel) a request
584  * @c: client state
585  * @oldreq: request to cancel
586  *
587  * This sents a flush for a particular request and links
588  * the flush request to the original request.  The current
589  * code only supports a single flush request although the protocol
590  * allows for multiple flush requests to be sent for a single request.
591  *
592  */
593 
594 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
595 {
596 	struct p9_req_t *req;
597 	s16 oldtag;
598 	int err;
599 
600 	err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
601 	if (err)
602 		return err;
603 
604 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
605 
606 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
607 	if (IS_ERR(req))
608 		return PTR_ERR(req);
609 
610 	/* if we haven't received a response for oldreq,
611 	 * remove it from the list
612 	 */
613 	if (READ_ONCE(oldreq->status) == REQ_STATUS_SENT) {
614 		if (c->trans_mod->cancelled)
615 			c->trans_mod->cancelled(c, oldreq);
616 	}
617 
618 	p9_req_put(c, req);
619 	return 0;
620 }
621 
622 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
623 					      int8_t type, uint t_size, uint r_size,
624 					      const char *fmt, va_list ap)
625 {
626 	int err;
627 	struct p9_req_t *req;
628 	va_list apc;
629 
630 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
631 
632 	/* we allow for any status other than disconnected */
633 	if (c->status == Disconnected)
634 		return ERR_PTR(-EIO);
635 
636 	/* if status is begin_disconnected we allow only clunk request */
637 	if (c->status == BeginDisconnect && type != P9_TCLUNK)
638 		return ERR_PTR(-EIO);
639 
640 	va_copy(apc, ap);
641 	req = p9_tag_alloc(c, type, t_size, r_size, fmt, apc);
642 	va_end(apc);
643 	if (IS_ERR(req))
644 		return req;
645 
646 	/* marshall the data */
647 	p9pdu_prepare(&req->tc, req->tc.tag, type);
648 	err = p9pdu_vwritef(&req->tc, c->proto_version, fmt, ap);
649 	if (err)
650 		goto reterr;
651 	p9pdu_finalize(c, &req->tc);
652 	trace_9p_client_req(c, type, req->tc.tag);
653 	return req;
654 reterr:
655 	p9_req_put(c, req);
656 	/* We have to put also the 2nd reference as it won't be used */
657 	p9_req_put(c, req);
658 	return ERR_PTR(err);
659 }
660 
661 /**
662  * p9_client_rpc - issue a request and wait for a response
663  * @c: client session
664  * @type: type of request
665  * @fmt: protocol format string (see protocol.c)
666  *
667  * Returns request structure (which client must free using p9_req_put)
668  */
669 
670 static struct p9_req_t *
671 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
672 {
673 	va_list ap;
674 	int sigpending, err;
675 	unsigned long flags;
676 	struct p9_req_t *req;
677 	/* Passing zero for tsize/rsize to p9_client_prepare_req() tells it to
678 	 * auto determine an appropriate (small) request/response size
679 	 * according to actual message data being sent. Currently RDMA
680 	 * transport is excluded from this response message size optimization,
681 	 * as it would not cope with it, due to its pooled response buffers
682 	 * (using an optimized request size for RDMA as well though).
683 	 */
684 	const uint tsize = 0;
685 	const uint rsize = c->trans_mod->pooled_rbuffers ? c->msize : 0;
686 
687 	va_start(ap, fmt);
688 	req = p9_client_prepare_req(c, type, tsize, rsize, fmt, ap);
689 	va_end(ap);
690 	if (IS_ERR(req))
691 		return req;
692 
693 	req->tc.zc = false;
694 	req->rc.zc = false;
695 
696 	if (signal_pending(current)) {
697 		sigpending = 1;
698 		clear_thread_flag(TIF_SIGPENDING);
699 	} else {
700 		sigpending = 0;
701 	}
702 
703 	err = c->trans_mod->request(c, req);
704 	if (err < 0) {
705 		/* write won't happen */
706 		p9_req_put(c, req);
707 		if (err != -ERESTARTSYS && err != -EFAULT)
708 			c->status = Disconnected;
709 		goto recalc_sigpending;
710 	}
711 again:
712 	/* Wait for the response */
713 	err = wait_event_killable(req->wq,
714 				  READ_ONCE(req->status) >= REQ_STATUS_RCVD);
715 
716 	/* Make sure our req is coherent with regard to updates in other
717 	 * threads - echoes to wmb() in the callback
718 	 */
719 	smp_rmb();
720 
721 	if (err == -ERESTARTSYS && c->status == Connected &&
722 	    type == P9_TFLUSH) {
723 		sigpending = 1;
724 		clear_thread_flag(TIF_SIGPENDING);
725 		goto again;
726 	}
727 
728 	if (READ_ONCE(req->status) == REQ_STATUS_ERROR) {
729 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
730 		err = req->t_err;
731 	}
732 	if (err == -ERESTARTSYS && c->status == Connected) {
733 		p9_debug(P9_DEBUG_MUX, "flushing\n");
734 		sigpending = 1;
735 		clear_thread_flag(TIF_SIGPENDING);
736 
737 		if (c->trans_mod->cancel(c, req))
738 			p9_client_flush(c, req);
739 
740 		/* if we received the response anyway, don't signal error */
741 		if (READ_ONCE(req->status) == REQ_STATUS_RCVD)
742 			err = 0;
743 	}
744 recalc_sigpending:
745 	if (sigpending) {
746 		spin_lock_irqsave(&current->sighand->siglock, flags);
747 		recalc_sigpending();
748 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
749 	}
750 	if (err < 0)
751 		goto reterr;
752 
753 	err = p9_check_errors(c, req);
754 	trace_9p_client_res(c, type, req->rc.tag, err);
755 	if (!err)
756 		return req;
757 reterr:
758 	p9_req_put(c, req);
759 	return ERR_PTR(safe_errno(err));
760 }
761 
762 /**
763  * p9_client_zc_rpc - issue a request and wait for a response
764  * @c: client session
765  * @type: type of request
766  * @uidata: destination for zero copy read
767  * @uodata: source for zero copy write
768  * @inlen: read buffer size
769  * @olen: write buffer size
770  * @in_hdrlen: reader header size, This is the size of response protocol data
771  * @fmt: protocol format string (see protocol.c)
772  *
773  * Returns request structure (which client must free using p9_req_put)
774  */
775 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
776 					 struct iov_iter *uidata,
777 					 struct iov_iter *uodata,
778 					 int inlen, int olen, int in_hdrlen,
779 					 const char *fmt, ...)
780 {
781 	va_list ap;
782 	int sigpending, err;
783 	unsigned long flags;
784 	struct p9_req_t *req;
785 
786 	va_start(ap, fmt);
787 	/* We allocate a inline protocol data of only 4k bytes.
788 	 * The actual content is passed in zero-copy fashion.
789 	 */
790 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, P9_ZC_HDR_SZ, fmt, ap);
791 	va_end(ap);
792 	if (IS_ERR(req))
793 		return req;
794 
795 	req->tc.zc = true;
796 	req->rc.zc = true;
797 
798 	if (signal_pending(current)) {
799 		sigpending = 1;
800 		clear_thread_flag(TIF_SIGPENDING);
801 	} else {
802 		sigpending = 0;
803 	}
804 
805 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
806 				       inlen, olen, in_hdrlen);
807 	if (err < 0) {
808 		if (err == -EIO)
809 			c->status = Disconnected;
810 		if (err != -ERESTARTSYS)
811 			goto recalc_sigpending;
812 	}
813 	if (READ_ONCE(req->status) == REQ_STATUS_ERROR) {
814 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
815 		err = req->t_err;
816 	}
817 	if (err == -ERESTARTSYS && c->status == Connected) {
818 		p9_debug(P9_DEBUG_MUX, "flushing\n");
819 		sigpending = 1;
820 		clear_thread_flag(TIF_SIGPENDING);
821 
822 		if (c->trans_mod->cancel(c, req))
823 			p9_client_flush(c, req);
824 
825 		/* if we received the response anyway, don't signal error */
826 		if (READ_ONCE(req->status) == REQ_STATUS_RCVD)
827 			err = 0;
828 	}
829 recalc_sigpending:
830 	if (sigpending) {
831 		spin_lock_irqsave(&current->sighand->siglock, flags);
832 		recalc_sigpending();
833 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
834 	}
835 	if (err < 0)
836 		goto reterr;
837 
838 	err = p9_check_errors(c, req);
839 	trace_9p_client_res(c, type, req->rc.tag, err);
840 	if (!err)
841 		return req;
842 reterr:
843 	p9_req_put(c, req);
844 	return ERR_PTR(safe_errno(err));
845 }
846 
847 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
848 {
849 	int ret;
850 	struct p9_fid *fid;
851 
852 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
853 	fid = kzalloc(sizeof(*fid), GFP_KERNEL);
854 	if (!fid)
855 		return NULL;
856 
857 	fid->mode = -1;
858 	fid->uid = current_fsuid();
859 	fid->clnt = clnt;
860 	refcount_set(&fid->count, 1);
861 
862 	idr_preload(GFP_KERNEL);
863 	spin_lock_irq(&clnt->lock);
864 	ret = idr_alloc_u32(&clnt->fids, fid, &fid->fid, P9_NOFID - 1,
865 			    GFP_NOWAIT);
866 	spin_unlock_irq(&clnt->lock);
867 	idr_preload_end();
868 	if (!ret) {
869 		trace_9p_fid_ref(fid, P9_FID_REF_CREATE);
870 		return fid;
871 	}
872 
873 	kfree(fid);
874 	return NULL;
875 }
876 
877 static void p9_fid_destroy(struct p9_fid *fid)
878 {
879 	struct p9_client *clnt;
880 	unsigned long flags;
881 
882 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
883 	trace_9p_fid_ref(fid, P9_FID_REF_DESTROY);
884 	clnt = fid->clnt;
885 	spin_lock_irqsave(&clnt->lock, flags);
886 	idr_remove(&clnt->fids, fid->fid);
887 	spin_unlock_irqrestore(&clnt->lock, flags);
888 	kfree(fid->rdir);
889 	kfree(fid);
890 }
891 
892 /* We also need to export tracepoint symbols for tracepoint_enabled() */
893 EXPORT_TRACEPOINT_SYMBOL(9p_fid_ref);
894 
895 void do_trace_9p_fid_get(struct p9_fid *fid)
896 {
897 	trace_9p_fid_ref(fid, P9_FID_REF_GET);
898 }
899 EXPORT_SYMBOL(do_trace_9p_fid_get);
900 
901 void do_trace_9p_fid_put(struct p9_fid *fid)
902 {
903 	trace_9p_fid_ref(fid, P9_FID_REF_PUT);
904 }
905 EXPORT_SYMBOL(do_trace_9p_fid_put);
906 
907 static int p9_client_version(struct p9_client *c)
908 {
909 	int err;
910 	struct p9_req_t *req;
911 	char *version = NULL;
912 	int msize;
913 
914 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
915 		 c->msize, c->proto_version);
916 
917 	switch (c->proto_version) {
918 	case p9_proto_2000L:
919 		req = p9_client_rpc(c, P9_TVERSION, "ds",
920 				    c->msize, "9P2000.L");
921 		break;
922 	case p9_proto_2000u:
923 		req = p9_client_rpc(c, P9_TVERSION, "ds",
924 				    c->msize, "9P2000.u");
925 		break;
926 	case p9_proto_legacy:
927 		req = p9_client_rpc(c, P9_TVERSION, "ds",
928 				    c->msize, "9P2000");
929 		break;
930 	default:
931 		return -EINVAL;
932 	}
933 
934 	if (IS_ERR(req))
935 		return PTR_ERR(req);
936 
937 	err = p9pdu_readf(&req->rc, c->proto_version, "ds", &msize, &version);
938 	if (err) {
939 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
940 		trace_9p_protocol_dump(c, &req->rc);
941 		goto error;
942 	}
943 
944 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
945 	if (!strncmp(version, "9P2000.L", 8)) {
946 		c->proto_version = p9_proto_2000L;
947 	} else if (!strncmp(version, "9P2000.u", 8)) {
948 		c->proto_version = p9_proto_2000u;
949 	} else if (!strncmp(version, "9P2000", 6)) {
950 		c->proto_version = p9_proto_legacy;
951 	} else {
952 		p9_debug(P9_DEBUG_ERROR,
953 			 "server returned an unknown version: %s\n", version);
954 		err = -EREMOTEIO;
955 		goto error;
956 	}
957 
958 	if (msize < 4096) {
959 		p9_debug(P9_DEBUG_ERROR,
960 			 "server returned a msize < 4096: %d\n", msize);
961 		err = -EREMOTEIO;
962 		goto error;
963 	}
964 	if (msize < c->msize)
965 		c->msize = msize;
966 
967 error:
968 	kfree(version);
969 	p9_req_put(c, req);
970 
971 	return err;
972 }
973 
974 struct p9_client *p9_client_create(const char *dev_name, char *options)
975 {
976 	int err;
977 	struct p9_client *clnt;
978 	char *client_id;
979 
980 	clnt = kmalloc(sizeof(*clnt), GFP_KERNEL);
981 	if (!clnt)
982 		return ERR_PTR(-ENOMEM);
983 
984 	clnt->trans_mod = NULL;
985 	clnt->trans = NULL;
986 	clnt->fcall_cache = NULL;
987 
988 	client_id = utsname()->nodename;
989 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
990 
991 	spin_lock_init(&clnt->lock);
992 	idr_init(&clnt->fids);
993 	idr_init(&clnt->reqs);
994 
995 	err = parse_opts(options, clnt);
996 	if (err < 0)
997 		goto free_client;
998 
999 	if (!clnt->trans_mod)
1000 		clnt->trans_mod = v9fs_get_default_trans();
1001 
1002 	if (!clnt->trans_mod) {
1003 		err = -EPROTONOSUPPORT;
1004 		p9_debug(P9_DEBUG_ERROR,
1005 			 "No transport defined or default transport\n");
1006 		goto free_client;
1007 	}
1008 
1009 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
1010 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
1011 
1012 	err = clnt->trans_mod->create(clnt, dev_name, options);
1013 	if (err)
1014 		goto put_trans;
1015 
1016 	if (clnt->msize > clnt->trans_mod->maxsize) {
1017 		clnt->msize = clnt->trans_mod->maxsize;
1018 		pr_info("Limiting 'msize' to %d as this is the maximum "
1019 			"supported by transport %s\n",
1020 			clnt->msize, clnt->trans_mod->name
1021 		);
1022 	}
1023 
1024 	if (clnt->msize < 4096) {
1025 		p9_debug(P9_DEBUG_ERROR,
1026 			 "Please specify a msize of at least 4k\n");
1027 		err = -EINVAL;
1028 		goto close_trans;
1029 	}
1030 
1031 	err = p9_client_version(clnt);
1032 	if (err)
1033 		goto close_trans;
1034 
1035 	/* P9_HDRSZ + 4 is the smallest packet header we can have that is
1036 	 * followed by data accessed from userspace by read
1037 	 */
1038 	clnt->fcall_cache =
1039 		kmem_cache_create_usercopy("9p-fcall-cache", clnt->msize,
1040 					   0, 0, P9_HDRSZ + 4,
1041 					   clnt->msize - (P9_HDRSZ + 4),
1042 					   NULL);
1043 
1044 	return clnt;
1045 
1046 close_trans:
1047 	clnt->trans_mod->close(clnt);
1048 put_trans:
1049 	v9fs_put_trans(clnt->trans_mod);
1050 free_client:
1051 	kfree(clnt);
1052 	return ERR_PTR(err);
1053 }
1054 EXPORT_SYMBOL(p9_client_create);
1055 
1056 void p9_client_destroy(struct p9_client *clnt)
1057 {
1058 	struct p9_fid *fid;
1059 	int id;
1060 
1061 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1062 
1063 	if (clnt->trans_mod)
1064 		clnt->trans_mod->close(clnt);
1065 
1066 	v9fs_put_trans(clnt->trans_mod);
1067 
1068 	idr_for_each_entry(&clnt->fids, fid, id) {
1069 		pr_info("Found fid %d not clunked\n", fid->fid);
1070 		p9_fid_destroy(fid);
1071 	}
1072 
1073 	p9_tag_cleanup(clnt);
1074 
1075 	kmem_cache_destroy(clnt->fcall_cache);
1076 	kfree(clnt);
1077 }
1078 EXPORT_SYMBOL(p9_client_destroy);
1079 
1080 void p9_client_disconnect(struct p9_client *clnt)
1081 {
1082 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1083 	clnt->status = Disconnected;
1084 }
1085 EXPORT_SYMBOL(p9_client_disconnect);
1086 
1087 void p9_client_begin_disconnect(struct p9_client *clnt)
1088 {
1089 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1090 	clnt->status = BeginDisconnect;
1091 }
1092 EXPORT_SYMBOL(p9_client_begin_disconnect);
1093 
1094 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1095 				const char *uname, kuid_t n_uname,
1096 				const char *aname)
1097 {
1098 	int err;
1099 	struct p9_req_t *req;
1100 	struct p9_fid *fid;
1101 	struct p9_qid qid;
1102 
1103 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1104 		 afid ? afid->fid : -1, uname, aname);
1105 	fid = p9_fid_create(clnt);
1106 	if (!fid) {
1107 		err = -ENOMEM;
1108 		goto error;
1109 	}
1110 	fid->uid = n_uname;
1111 
1112 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
1113 			    afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
1114 	if (IS_ERR(req)) {
1115 		err = PTR_ERR(req);
1116 		goto error;
1117 	}
1118 
1119 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", &qid);
1120 	if (err) {
1121 		trace_9p_protocol_dump(clnt, &req->rc);
1122 		p9_req_put(clnt, req);
1123 		goto error;
1124 	}
1125 
1126 	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
1127 		 qid.type, qid.path, qid.version);
1128 
1129 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1130 
1131 	p9_req_put(clnt, req);
1132 	return fid;
1133 
1134 error:
1135 	if (fid)
1136 		p9_fid_destroy(fid);
1137 	return ERR_PTR(err);
1138 }
1139 EXPORT_SYMBOL(p9_client_attach);
1140 
1141 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
1142 			      const unsigned char * const *wnames, int clone)
1143 {
1144 	int err;
1145 	struct p9_client *clnt;
1146 	struct p9_fid *fid;
1147 	struct p9_qid *wqids;
1148 	struct p9_req_t *req;
1149 	u16 nwqids, count;
1150 
1151 	wqids = NULL;
1152 	clnt = oldfid->clnt;
1153 	if (clone) {
1154 		fid = p9_fid_create(clnt);
1155 		if (!fid) {
1156 			err = -ENOMEM;
1157 			goto error;
1158 		}
1159 
1160 		fid->uid = oldfid->uid;
1161 	} else {
1162 		fid = oldfid;
1163 	}
1164 
1165 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1166 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1167 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1168 			    nwname, wnames);
1169 	if (IS_ERR(req)) {
1170 		err = PTR_ERR(req);
1171 		goto error;
1172 	}
1173 
1174 	err = p9pdu_readf(&req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1175 	if (err) {
1176 		trace_9p_protocol_dump(clnt, &req->rc);
1177 		p9_req_put(clnt, req);
1178 		goto clunk_fid;
1179 	}
1180 	p9_req_put(clnt, req);
1181 
1182 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1183 
1184 	if (nwqids != nwname) {
1185 		err = -ENOENT;
1186 		goto clunk_fid;
1187 	}
1188 
1189 	for (count = 0; count < nwqids; count++)
1190 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1191 			 count, wqids[count].type,
1192 			 wqids[count].path,
1193 			 wqids[count].version);
1194 
1195 	if (nwname)
1196 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1197 	else
1198 		memmove(&fid->qid, &oldfid->qid, sizeof(struct p9_qid));
1199 
1200 	kfree(wqids);
1201 	return fid;
1202 
1203 clunk_fid:
1204 	kfree(wqids);
1205 	p9_fid_put(fid);
1206 	fid = NULL;
1207 
1208 error:
1209 	if (fid && fid != oldfid)
1210 		p9_fid_destroy(fid);
1211 
1212 	return ERR_PTR(err);
1213 }
1214 EXPORT_SYMBOL(p9_client_walk);
1215 
1216 int p9_client_open(struct p9_fid *fid, int mode)
1217 {
1218 	int err;
1219 	struct p9_client *clnt;
1220 	struct p9_req_t *req;
1221 	struct p9_qid qid;
1222 	int iounit;
1223 
1224 	clnt = fid->clnt;
1225 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1226 		 p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1227 
1228 	if (fid->mode != -1)
1229 		return -EINVAL;
1230 
1231 	if (p9_is_proto_dotl(clnt))
1232 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode & P9L_MODE_MASK);
1233 	else
1234 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode & P9L_MODE_MASK);
1235 	if (IS_ERR(req)) {
1236 		err = PTR_ERR(req);
1237 		goto error;
1238 	}
1239 
1240 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1241 	if (err) {
1242 		trace_9p_protocol_dump(clnt, &req->rc);
1243 		goto free_and_error;
1244 	}
1245 
1246 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1247 		 p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1248 		 qid.path, qid.version, iounit);
1249 
1250 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1251 	fid->mode = mode;
1252 	fid->iounit = iounit;
1253 
1254 free_and_error:
1255 	p9_req_put(clnt, req);
1256 error:
1257 	return err;
1258 }
1259 EXPORT_SYMBOL(p9_client_open);
1260 
1261 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags,
1262 			  u32 mode, kgid_t gid, struct p9_qid *qid)
1263 {
1264 	int err;
1265 	struct p9_client *clnt;
1266 	struct p9_req_t *req;
1267 	int iounit;
1268 
1269 	p9_debug(P9_DEBUG_9P,
1270 		 ">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1271 		 ofid->fid, name, flags, mode,
1272 		 from_kgid(&init_user_ns, gid));
1273 	clnt = ofid->clnt;
1274 
1275 	if (ofid->mode != -1)
1276 		return -EINVAL;
1277 
1278 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1279 			    mode & P9L_MODE_MASK, gid);
1280 	if (IS_ERR(req)) {
1281 		err = PTR_ERR(req);
1282 		goto error;
1283 	}
1284 
1285 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", qid, &iounit);
1286 	if (err) {
1287 		trace_9p_protocol_dump(clnt, &req->rc);
1288 		goto free_and_error;
1289 	}
1290 
1291 	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1292 		 qid->type, qid->path, qid->version, iounit);
1293 
1294 	memmove(&ofid->qid, qid, sizeof(struct p9_qid));
1295 	ofid->mode = flags;
1296 	ofid->iounit = iounit;
1297 
1298 free_and_error:
1299 	p9_req_put(clnt, req);
1300 error:
1301 	return err;
1302 }
1303 EXPORT_SYMBOL(p9_client_create_dotl);
1304 
1305 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1306 		     char *extension)
1307 {
1308 	int err;
1309 	struct p9_client *clnt;
1310 	struct p9_req_t *req;
1311 	struct p9_qid qid;
1312 	int iounit;
1313 
1314 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1315 		 fid->fid, name, perm, mode);
1316 	clnt = fid->clnt;
1317 
1318 	if (fid->mode != -1)
1319 		return -EINVAL;
1320 
1321 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1322 			    mode & P9L_MODE_MASK, extension);
1323 	if (IS_ERR(req)) {
1324 		err = PTR_ERR(req);
1325 		goto error;
1326 	}
1327 
1328 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1329 	if (err) {
1330 		trace_9p_protocol_dump(clnt, &req->rc);
1331 		goto free_and_error;
1332 	}
1333 
1334 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1335 		 qid.type, qid.path, qid.version, iounit);
1336 
1337 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1338 	fid->mode = mode;
1339 	fid->iounit = iounit;
1340 
1341 free_and_error:
1342 	p9_req_put(clnt, req);
1343 error:
1344 	return err;
1345 }
1346 EXPORT_SYMBOL(p9_client_fcreate);
1347 
1348 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1349 		      const char *symtgt, kgid_t gid, struct p9_qid *qid)
1350 {
1351 	int err;
1352 	struct p9_client *clnt;
1353 	struct p9_req_t *req;
1354 
1355 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1356 		 dfid->fid, name, symtgt);
1357 	clnt = dfid->clnt;
1358 
1359 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1360 			    gid);
1361 	if (IS_ERR(req)) {
1362 		err = PTR_ERR(req);
1363 		goto error;
1364 	}
1365 
1366 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
1367 	if (err) {
1368 		trace_9p_protocol_dump(clnt, &req->rc);
1369 		goto free_and_error;
1370 	}
1371 
1372 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1373 		 qid->type, qid->path, qid->version);
1374 
1375 free_and_error:
1376 	p9_req_put(clnt, req);
1377 error:
1378 	return err;
1379 }
1380 EXPORT_SYMBOL(p9_client_symlink);
1381 
1382 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1383 {
1384 	struct p9_client *clnt;
1385 	struct p9_req_t *req;
1386 
1387 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1388 		 dfid->fid, oldfid->fid, newname);
1389 	clnt = dfid->clnt;
1390 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1391 			    newname);
1392 	if (IS_ERR(req))
1393 		return PTR_ERR(req);
1394 
1395 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1396 	p9_req_put(clnt, req);
1397 	return 0;
1398 }
1399 EXPORT_SYMBOL(p9_client_link);
1400 
1401 int p9_client_fsync(struct p9_fid *fid, int datasync)
1402 {
1403 	int err = 0;
1404 	struct p9_client *clnt;
1405 	struct p9_req_t *req;
1406 
1407 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1408 		 fid->fid, datasync);
1409 	clnt = fid->clnt;
1410 
1411 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1412 	if (IS_ERR(req)) {
1413 		err = PTR_ERR(req);
1414 		goto error;
1415 	}
1416 
1417 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1418 
1419 	p9_req_put(clnt, req);
1420 
1421 error:
1422 	return err;
1423 }
1424 EXPORT_SYMBOL(p9_client_fsync);
1425 
1426 int p9_client_clunk(struct p9_fid *fid)
1427 {
1428 	int err = 0;
1429 	struct p9_client *clnt;
1430 	struct p9_req_t *req;
1431 	int retries = 0;
1432 
1433 again:
1434 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n",
1435 		 fid->fid, retries);
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 = 0;
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 	clnt = fid->clnt;
1470 
1471 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1472 	if (IS_ERR(req)) {
1473 		err = PTR_ERR(req);
1474 		goto error;
1475 	}
1476 
1477 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1478 
1479 	p9_req_put(clnt, req);
1480 error:
1481 	if (err == -ERESTARTSYS)
1482 		p9_fid_put(fid);
1483 	else
1484 		p9_fid_destroy(fid);
1485 	return err;
1486 }
1487 EXPORT_SYMBOL(p9_client_remove);
1488 
1489 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1490 {
1491 	int err = 0;
1492 	struct p9_req_t *req;
1493 	struct p9_client *clnt;
1494 
1495 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1496 		 dfid->fid, name, flags);
1497 
1498 	clnt = dfid->clnt;
1499 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1500 	if (IS_ERR(req)) {
1501 		err = PTR_ERR(req);
1502 		goto error;
1503 	}
1504 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1505 
1506 	p9_req_put(clnt, req);
1507 error:
1508 	return err;
1509 }
1510 EXPORT_SYMBOL(p9_client_unlinkat);
1511 
1512 int
1513 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1514 {
1515 	int total = 0;
1516 	*err = 0;
1517 
1518 	while (iov_iter_count(to)) {
1519 		int count;
1520 
1521 		count = p9_client_read_once(fid, offset, to, err);
1522 		if (!count || *err)
1523 			break;
1524 		offset += count;
1525 		total += count;
1526 	}
1527 	return total;
1528 }
1529 EXPORT_SYMBOL(p9_client_read);
1530 
1531 int
1532 p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
1533 		    int *err)
1534 {
1535 	struct p9_client *clnt = fid->clnt;
1536 	struct p9_req_t *req;
1537 	int count = iov_iter_count(to);
1538 	int rsize, received, non_zc = 0;
1539 	char *dataptr;
1540 
1541 	*err = 0;
1542 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %zu\n",
1543 		 fid->fid, offset, iov_iter_count(to));
1544 
1545 	rsize = fid->iounit;
1546 	if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1547 		rsize = clnt->msize - P9_IOHDRSZ;
1548 
1549 	if (count < rsize)
1550 		rsize = count;
1551 
1552 	/* Don't bother zerocopy for small IO (< 1024) */
1553 	if (clnt->trans_mod->zc_request && rsize > 1024) {
1554 		/* response header len is 11
1555 		 * PDU Header(7) + IO Size (4)
1556 		 */
1557 		req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1558 				       0, 11, "dqd", fid->fid,
1559 				       offset, rsize);
1560 	} else {
1561 		non_zc = 1;
1562 		req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1563 				    rsize);
1564 	}
1565 	if (IS_ERR(req)) {
1566 		*err = PTR_ERR(req);
1567 		if (!non_zc)
1568 			iov_iter_revert(to, count - iov_iter_count(to));
1569 		return 0;
1570 	}
1571 
1572 	*err = p9pdu_readf(&req->rc, clnt->proto_version,
1573 			   "D", &received, &dataptr);
1574 	if (*err) {
1575 		if (!non_zc)
1576 			iov_iter_revert(to, count - iov_iter_count(to));
1577 		trace_9p_protocol_dump(clnt, &req->rc);
1578 		p9_req_put(clnt, req);
1579 		return 0;
1580 	}
1581 	if (rsize < received) {
1582 		pr_err("bogus RREAD count (%d > %d)\n", received, rsize);
1583 		received = rsize;
1584 	}
1585 
1586 	p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1587 
1588 	if (non_zc) {
1589 		int n = copy_to_iter(dataptr, received, to);
1590 
1591 		if (n != received) {
1592 			*err = -EFAULT;
1593 			p9_req_put(clnt, req);
1594 			return n;
1595 		}
1596 	} else {
1597 		iov_iter_revert(to, count - received - iov_iter_count(to));
1598 	}
1599 	p9_req_put(clnt, req);
1600 	return received;
1601 }
1602 EXPORT_SYMBOL(p9_client_read_once);
1603 
1604 int
1605 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1606 {
1607 	struct p9_client *clnt = fid->clnt;
1608 	struct p9_req_t *req;
1609 	int total = 0;
1610 	*err = 0;
1611 
1612 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n",
1613 		 fid->fid, offset, iov_iter_count(from));
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 		/* Don't bother zerocopy for small IO (< 1024) */
1627 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1628 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1629 					       rsize, P9_ZC_HDR_SZ, "dqd",
1630 					       fid->fid, offset, rsize);
1631 		} else {
1632 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1633 					    offset, rsize, from);
1634 		}
1635 		if (IS_ERR(req)) {
1636 			iov_iter_revert(from, count - iov_iter_count(from));
1637 			*err = PTR_ERR(req);
1638 			break;
1639 		}
1640 
1641 		*err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &written);
1642 		if (*err) {
1643 			iov_iter_revert(from, count - iov_iter_count(from));
1644 			trace_9p_protocol_dump(clnt, &req->rc);
1645 			p9_req_put(clnt, req);
1646 			break;
1647 		}
1648 		if (rsize < written) {
1649 			pr_err("bogus RWRITE count (%d > %d)\n", written, rsize);
1650 			written = rsize;
1651 		}
1652 
1653 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1654 
1655 		p9_req_put(clnt, req);
1656 		iov_iter_revert(from, count - written - iov_iter_count(from));
1657 		total += written;
1658 		offset += written;
1659 	}
1660 	return total;
1661 }
1662 EXPORT_SYMBOL(p9_client_write);
1663 
1664 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1665 {
1666 	int err;
1667 	struct p9_client *clnt;
1668 	struct p9_wstat *ret;
1669 	struct p9_req_t *req;
1670 	u16 ignored;
1671 
1672 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1673 
1674 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1675 	if (!ret)
1676 		return ERR_PTR(-ENOMEM);
1677 
1678 	clnt = fid->clnt;
1679 
1680 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1681 	if (IS_ERR(req)) {
1682 		err = PTR_ERR(req);
1683 		goto error;
1684 	}
1685 
1686 	err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
1687 	if (err) {
1688 		trace_9p_protocol_dump(clnt, &req->rc);
1689 		p9_req_put(clnt, req);
1690 		goto error;
1691 	}
1692 
1693 	p9_debug(P9_DEBUG_9P,
1694 		 "<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1695 		 "<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1696 		 "<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1697 		 "<<<    uid=%d gid=%d n_muid=%d\n",
1698 		 ret->size, ret->type, ret->dev, ret->qid.type, ret->qid.path,
1699 		 ret->qid.version, ret->mode,
1700 		 ret->atime, ret->mtime, ret->length,
1701 		 ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1702 		 from_kuid(&init_user_ns, ret->n_uid),
1703 		 from_kgid(&init_user_ns, ret->n_gid),
1704 		 from_kuid(&init_user_ns, ret->n_muid));
1705 
1706 	p9_req_put(clnt, req);
1707 	return ret;
1708 
1709 error:
1710 	kfree(ret);
1711 	return ERR_PTR(err);
1712 }
1713 EXPORT_SYMBOL(p9_client_stat);
1714 
1715 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1716 					    u64 request_mask)
1717 {
1718 	int err;
1719 	struct p9_client *clnt;
1720 	struct p9_stat_dotl *ret;
1721 	struct p9_req_t *req;
1722 
1723 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1724 		 fid->fid, request_mask);
1725 
1726 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1727 	if (!ret)
1728 		return ERR_PTR(-ENOMEM);
1729 
1730 	clnt = fid->clnt;
1731 
1732 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1733 	if (IS_ERR(req)) {
1734 		err = PTR_ERR(req);
1735 		goto error;
1736 	}
1737 
1738 	err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
1739 	if (err) {
1740 		trace_9p_protocol_dump(clnt, &req->rc);
1741 		p9_req_put(clnt, req);
1742 		goto error;
1743 	}
1744 
1745 	p9_debug(P9_DEBUG_9P, "<<< RGETATTR st_result_mask=%lld\n"
1746 		 "<<< qid=%x.%llx.%x\n"
1747 		 "<<< st_mode=%8.8x st_nlink=%llu\n"
1748 		 "<<< st_uid=%d st_gid=%d\n"
1749 		 "<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1750 		 "<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1751 		 "<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1752 		 "<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1753 		 "<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1754 		 "<<< st_gen=%lld st_data_version=%lld\n",
1755 		 ret->st_result_mask,
1756 		 ret->qid.type, ret->qid.path, ret->qid.version,
1757 		 ret->st_mode, ret->st_nlink,
1758 		 from_kuid(&init_user_ns, ret->st_uid),
1759 		 from_kgid(&init_user_ns, ret->st_gid),
1760 		 ret->st_rdev, ret->st_size, ret->st_blksize, ret->st_blocks,
1761 		 ret->st_atime_sec, ret->st_atime_nsec,
1762 		 ret->st_mtime_sec, ret->st_mtime_nsec,
1763 		 ret->st_ctime_sec, ret->st_ctime_nsec,
1764 		 ret->st_btime_sec, ret->st_btime_nsec,
1765 		 ret->st_gen, ret->st_data_version);
1766 
1767 	p9_req_put(clnt, req);
1768 	return ret;
1769 
1770 error:
1771 	kfree(ret);
1772 	return ERR_PTR(err);
1773 }
1774 EXPORT_SYMBOL(p9_client_getattr_dotl);
1775 
1776 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1777 {
1778 	int ret;
1779 
1780 	/* NOTE: size shouldn't include its own length */
1781 	/* size[2] type[2] dev[4] qid[13] */
1782 	/* mode[4] atime[4] mtime[4] length[8]*/
1783 	/* name[s] uid[s] gid[s] muid[s] */
1784 	ret = 2 + 4 + 13 + 4 + 4 + 4 + 8 + 2 + 2 + 2 + 2;
1785 
1786 	if (wst->name)
1787 		ret += strlen(wst->name);
1788 	if (wst->uid)
1789 		ret += strlen(wst->uid);
1790 	if (wst->gid)
1791 		ret += strlen(wst->gid);
1792 	if (wst->muid)
1793 		ret += strlen(wst->muid);
1794 
1795 	if (proto_version == p9_proto_2000u ||
1796 	    proto_version == p9_proto_2000L) {
1797 		/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1798 		ret += 2 + 4 + 4 + 4;
1799 		if (wst->extension)
1800 			ret += strlen(wst->extension);
1801 	}
1802 
1803 	return ret;
1804 }
1805 
1806 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1807 {
1808 	int err = 0;
1809 	struct p9_req_t *req;
1810 	struct p9_client *clnt;
1811 
1812 	clnt = fid->clnt;
1813 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1814 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n",
1815 		 fid->fid);
1816 	p9_debug(P9_DEBUG_9P,
1817 		 "     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1818 		 "     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1819 		 "     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1820 		 "     uid=%d gid=%d n_muid=%d\n",
1821 		 wst->size, wst->type, wst->dev, wst->qid.type,
1822 		 wst->qid.path, wst->qid.version,
1823 		 wst->mode, wst->atime, wst->mtime, wst->length,
1824 		 wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1825 		 from_kuid(&init_user_ns, wst->n_uid),
1826 		 from_kgid(&init_user_ns, wst->n_gid),
1827 		 from_kuid(&init_user_ns, wst->n_muid));
1828 
1829 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS",
1830 			    fid->fid, wst->size + 2, wst);
1831 	if (IS_ERR(req)) {
1832 		err = PTR_ERR(req);
1833 		goto error;
1834 	}
1835 
1836 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1837 
1838 	p9_req_put(clnt, req);
1839 error:
1840 	return err;
1841 }
1842 EXPORT_SYMBOL(p9_client_wstat);
1843 
1844 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1845 {
1846 	int err = 0;
1847 	struct p9_req_t *req;
1848 	struct p9_client *clnt;
1849 
1850 	clnt = fid->clnt;
1851 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1852 	p9_debug(P9_DEBUG_9P, "    valid=%x mode=%x uid=%d gid=%d size=%lld\n",
1853 		 p9attr->valid, p9attr->mode,
1854 		 from_kuid(&init_user_ns, p9attr->uid),
1855 		 from_kgid(&init_user_ns, p9attr->gid),
1856 		 p9attr->size);
1857 	p9_debug(P9_DEBUG_9P, "    atime_sec=%lld atime_nsec=%lld\n",
1858 		 p9attr->atime_sec, p9attr->atime_nsec);
1859 	p9_debug(P9_DEBUG_9P, "    mtime_sec=%lld mtime_nsec=%lld\n",
1860 		 p9attr->mtime_sec, p9attr->mtime_nsec);
1861 
1862 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1863 
1864 	if (IS_ERR(req)) {
1865 		err = PTR_ERR(req);
1866 		goto error;
1867 	}
1868 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1869 	p9_req_put(clnt, req);
1870 error:
1871 	return err;
1872 }
1873 EXPORT_SYMBOL(p9_client_setattr);
1874 
1875 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1876 {
1877 	int err;
1878 	struct p9_req_t *req;
1879 	struct p9_client *clnt;
1880 
1881 	clnt = fid->clnt;
1882 
1883 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1884 
1885 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1886 	if (IS_ERR(req)) {
1887 		err = PTR_ERR(req);
1888 		goto error;
1889 	}
1890 
1891 	err = p9pdu_readf(&req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1892 			  &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1893 			  &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1894 	if (err) {
1895 		trace_9p_protocol_dump(clnt, &req->rc);
1896 		p9_req_put(clnt, req);
1897 		goto error;
1898 	}
1899 
1900 	p9_debug(P9_DEBUG_9P,
1901 		 "<<< RSTATFS fid %d type 0x%x bsize %u blocks %llu bfree %llu bavail %llu files %llu ffree %llu fsid %llu namelen %u\n",
1902 		 fid->fid, sb->type, sb->bsize, sb->blocks, sb->bfree,
1903 		 sb->bavail, sb->files, sb->ffree, sb->fsid, sb->namelen);
1904 
1905 	p9_req_put(clnt, req);
1906 error:
1907 	return err;
1908 }
1909 EXPORT_SYMBOL(p9_client_statfs);
1910 
1911 int p9_client_rename(struct p9_fid *fid,
1912 		     struct p9_fid *newdirfid, const char *name)
1913 {
1914 	int err = 0;
1915 	struct p9_req_t *req;
1916 	struct p9_client *clnt;
1917 
1918 	clnt = fid->clnt;
1919 
1920 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1921 		 fid->fid, newdirfid->fid, name);
1922 
1923 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1924 			    newdirfid->fid, name);
1925 	if (IS_ERR(req)) {
1926 		err = PTR_ERR(req);
1927 		goto error;
1928 	}
1929 
1930 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1931 
1932 	p9_req_put(clnt, req);
1933 error:
1934 	return err;
1935 }
1936 EXPORT_SYMBOL(p9_client_rename);
1937 
1938 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
1939 		       struct p9_fid *newdirfid, const char *new_name)
1940 {
1941 	int err = 0;
1942 	struct p9_req_t *req;
1943 	struct p9_client *clnt;
1944 
1945 	clnt = olddirfid->clnt;
1946 
1947 	p9_debug(P9_DEBUG_9P,
1948 		 ">>> TRENAMEAT olddirfid %d old name %s newdirfid %d new name %s\n",
1949 		 olddirfid->fid, old_name, newdirfid->fid, new_name);
1950 
1951 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
1952 			    old_name, newdirfid->fid, new_name);
1953 	if (IS_ERR(req)) {
1954 		err = PTR_ERR(req);
1955 		goto error;
1956 	}
1957 
1958 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
1959 		 newdirfid->fid, new_name);
1960 
1961 	p9_req_put(clnt, req);
1962 error:
1963 	return err;
1964 }
1965 EXPORT_SYMBOL(p9_client_renameat);
1966 
1967 /* An xattrwalk without @attr_name gives the fid for the lisxattr namespace
1968  */
1969 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
1970 				   const char *attr_name, u64 *attr_size)
1971 {
1972 	int err;
1973 	struct p9_req_t *req;
1974 	struct p9_client *clnt;
1975 	struct p9_fid *attr_fid;
1976 
1977 	clnt = file_fid->clnt;
1978 	attr_fid = p9_fid_create(clnt);
1979 	if (!attr_fid) {
1980 		err = -ENOMEM;
1981 		goto error;
1982 	}
1983 	p9_debug(P9_DEBUG_9P,
1984 		 ">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
1985 		 file_fid->fid, attr_fid->fid, attr_name);
1986 
1987 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
1988 			    file_fid->fid, attr_fid->fid, attr_name);
1989 	if (IS_ERR(req)) {
1990 		err = PTR_ERR(req);
1991 		goto error;
1992 	}
1993 	err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
1994 	if (err) {
1995 		trace_9p_protocol_dump(clnt, &req->rc);
1996 		p9_req_put(clnt, req);
1997 		goto clunk_fid;
1998 	}
1999 	p9_req_put(clnt, req);
2000 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
2001 		 attr_fid->fid, *attr_size);
2002 	return attr_fid;
2003 clunk_fid:
2004 	p9_fid_put(attr_fid);
2005 	attr_fid = NULL;
2006 error:
2007 	if (attr_fid && attr_fid != file_fid)
2008 		p9_fid_destroy(attr_fid);
2009 
2010 	return ERR_PTR(err);
2011 }
2012 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
2013 
2014 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
2015 			  u64 attr_size, int flags)
2016 {
2017 	int err = 0;
2018 	struct p9_req_t *req;
2019 	struct p9_client *clnt;
2020 
2021 	p9_debug(P9_DEBUG_9P,
2022 		 ">>> TXATTRCREATE fid %d name  %s size %llu flag %d\n",
2023 		 fid->fid, name, attr_size, flags);
2024 	clnt = fid->clnt;
2025 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
2026 			    fid->fid, name, attr_size, flags);
2027 	if (IS_ERR(req)) {
2028 		err = PTR_ERR(req);
2029 		goto error;
2030 	}
2031 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
2032 	p9_req_put(clnt, req);
2033 error:
2034 	return err;
2035 }
2036 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
2037 
2038 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
2039 {
2040 	int err, rsize, non_zc = 0;
2041 	struct p9_client *clnt;
2042 	struct p9_req_t *req;
2043 	char *dataptr;
2044 	struct kvec kv = {.iov_base = data, .iov_len = count};
2045 	struct iov_iter to;
2046 
2047 	iov_iter_kvec(&to, ITER_DEST, &kv, 1, count);
2048 
2049 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
2050 		 fid->fid, offset, count);
2051 
2052 	clnt = fid->clnt;
2053 
2054 	rsize = fid->iounit;
2055 	if (!rsize || rsize > clnt->msize - P9_READDIRHDRSZ)
2056 		rsize = clnt->msize - P9_READDIRHDRSZ;
2057 
2058 	if (count < rsize)
2059 		rsize = count;
2060 
2061 	/* Don't bother zerocopy for small IO (< 1024) */
2062 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2063 		/* response header len is 11
2064 		 * PDU Header(7) + IO Size (4)
2065 		 */
2066 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2067 				       11, "dqd", fid->fid, offset, rsize);
2068 	} else {
2069 		non_zc = 1;
2070 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2071 				    offset, rsize);
2072 	}
2073 	if (IS_ERR(req)) {
2074 		err = PTR_ERR(req);
2075 		goto error;
2076 	}
2077 
2078 	err = p9pdu_readf(&req->rc, clnt->proto_version, "D", &count, &dataptr);
2079 	if (err) {
2080 		trace_9p_protocol_dump(clnt, &req->rc);
2081 		goto free_and_error;
2082 	}
2083 	if (rsize < count) {
2084 		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
2085 		count = rsize;
2086 	}
2087 
2088 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
2089 
2090 	if (non_zc)
2091 		memmove(data, dataptr, count);
2092 
2093 	p9_req_put(clnt, req);
2094 	return count;
2095 
2096 free_and_error:
2097 	p9_req_put(clnt, req);
2098 error:
2099 	return err;
2100 }
2101 EXPORT_SYMBOL(p9_client_readdir);
2102 
2103 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2104 			 dev_t rdev, kgid_t gid, struct p9_qid *qid)
2105 {
2106 	int err;
2107 	struct p9_client *clnt;
2108 	struct p9_req_t *req;
2109 
2110 	clnt = fid->clnt;
2111 	p9_debug(P9_DEBUG_9P,
2112 		 ">>> TMKNOD fid %d name %s mode %d major %d minor %d\n",
2113 		 fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2114 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2115 			    MAJOR(rdev), MINOR(rdev), gid);
2116 	if (IS_ERR(req))
2117 		return PTR_ERR(req);
2118 
2119 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2120 	if (err) {
2121 		trace_9p_protocol_dump(clnt, &req->rc);
2122 		goto error;
2123 	}
2124 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n",
2125 		 qid->type, qid->path, qid->version);
2126 
2127 error:
2128 	p9_req_put(clnt, req);
2129 	return err;
2130 }
2131 EXPORT_SYMBOL(p9_client_mknod_dotl);
2132 
2133 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2134 			 kgid_t gid, struct p9_qid *qid)
2135 {
2136 	int err;
2137 	struct p9_client *clnt;
2138 	struct p9_req_t *req;
2139 
2140 	clnt = fid->clnt;
2141 	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
2142 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
2143 	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg",
2144 			    fid->fid, name, mode, gid);
2145 	if (IS_ERR(req))
2146 		return PTR_ERR(req);
2147 
2148 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2149 	if (err) {
2150 		trace_9p_protocol_dump(clnt, &req->rc);
2151 		goto error;
2152 	}
2153 	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
2154 		 qid->path, qid->version);
2155 
2156 error:
2157 	p9_req_put(clnt, req);
2158 	return err;
2159 }
2160 EXPORT_SYMBOL(p9_client_mkdir_dotl);
2161 
2162 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
2163 {
2164 	int err;
2165 	struct p9_client *clnt;
2166 	struct p9_req_t *req;
2167 
2168 	clnt = fid->clnt;
2169 	p9_debug(P9_DEBUG_9P,
2170 		 ">>> TLOCK fid %d type %i flags %d start %lld length %lld proc_id %d client_id %s\n",
2171 		 fid->fid, flock->type, flock->flags, flock->start,
2172 		 flock->length, flock->proc_id, flock->client_id);
2173 
2174 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2175 			    flock->flags, flock->start, flock->length,
2176 			    flock->proc_id, flock->client_id);
2177 
2178 	if (IS_ERR(req))
2179 		return PTR_ERR(req);
2180 
2181 	err = p9pdu_readf(&req->rc, clnt->proto_version, "b", status);
2182 	if (err) {
2183 		trace_9p_protocol_dump(clnt, &req->rc);
2184 		goto error;
2185 	}
2186 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2187 error:
2188 	p9_req_put(clnt, req);
2189 	return err;
2190 }
2191 EXPORT_SYMBOL(p9_client_lock_dotl);
2192 
2193 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2194 {
2195 	int err;
2196 	struct p9_client *clnt;
2197 	struct p9_req_t *req;
2198 
2199 	clnt = fid->clnt;
2200 	p9_debug(P9_DEBUG_9P,
2201 		 ">>> TGETLOCK fid %d, type %i start %lld length %lld proc_id %d client_id %s\n",
2202 		 fid->fid, glock->type, glock->start, glock->length,
2203 		 glock->proc_id, glock->client_id);
2204 
2205 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,
2206 			    glock->type, glock->start, glock->length,
2207 			    glock->proc_id, glock->client_id);
2208 
2209 	if (IS_ERR(req))
2210 		return PTR_ERR(req);
2211 
2212 	err = p9pdu_readf(&req->rc, clnt->proto_version, "bqqds", &glock->type,
2213 			  &glock->start, &glock->length, &glock->proc_id,
2214 			  &glock->client_id);
2215 	if (err) {
2216 		trace_9p_protocol_dump(clnt, &req->rc);
2217 		goto error;
2218 	}
2219 	p9_debug(P9_DEBUG_9P,
2220 		 "<<< RGETLOCK type %i start %lld length %lld proc_id %d client_id %s\n",
2221 		 glock->type, glock->start, glock->length,
2222 		 glock->proc_id, glock->client_id);
2223 error:
2224 	p9_req_put(clnt, req);
2225 	return err;
2226 }
2227 EXPORT_SYMBOL(p9_client_getlock_dotl);
2228 
2229 int p9_client_readlink(struct p9_fid *fid, char **target)
2230 {
2231 	int err;
2232 	struct p9_client *clnt;
2233 	struct p9_req_t *req;
2234 
2235 	clnt = fid->clnt;
2236 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2237 
2238 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2239 	if (IS_ERR(req))
2240 		return PTR_ERR(req);
2241 
2242 	err = p9pdu_readf(&req->rc, clnt->proto_version, "s", target);
2243 	if (err) {
2244 		trace_9p_protocol_dump(clnt, &req->rc);
2245 		goto error;
2246 	}
2247 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2248 error:
2249 	p9_req_put(clnt, req);
2250 	return err;
2251 }
2252 EXPORT_SYMBOL(p9_client_readlink);
2253 
2254 int __init p9_client_init(void)
2255 {
2256 	p9_req_cache = KMEM_CACHE(p9_req_t, SLAB_TYPESAFE_BY_RCU);
2257 	return p9_req_cache ? 0 : -ENOMEM;
2258 }
2259 
2260 void __exit p9_client_exit(void)
2261 {
2262 	kmem_cache_destroy(p9_req_cache);
2263 }
2264