xref: /linux/net/9p/client.c (revision a3f143c461444c0b56360bbf468615fa814a8372)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * 9P Client
4  *
5  *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
6  *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
7  */
8 
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 
11 #include <linux/module.h>
12 #include <linux/errno.h>
13 #include <linux/fs.h>
14 #include <linux/poll.h>
15 #include <linux/idr.h>
16 #include <linux/mutex.h>
17 #include <linux/slab.h>
18 #include <linux/sched/signal.h>
19 #include <linux/uaccess.h>
20 #include <linux/uio.h>
21 #include <linux/netfs.h>
22 #include <net/9p/9p.h>
23 #include <linux/parser.h>
24 #include <linux/seq_file.h>
25 #include <net/9p/client.h>
26 #include <net/9p/transport.h>
27 #include "protocol.h"
28 
29 #define CREATE_TRACE_POINTS
30 #include <trace/events/9p.h>
31 
32 /* DEFAULT MSIZE = 32 pages worth of payload + P9_HDRSZ +
33  * room for write (16 extra) or read (11 extra) operands.
34  */
35 
36 #define DEFAULT_MSIZE ((128 * 1024) + P9_IOHDRSZ)
37 
38 /* Client Option Parsing (code inspired by NFS code)
39  *  - a little lazy - parse all client options
40  */
41 
42 enum {
43 	Opt_msize,
44 	Opt_trans,
45 	Opt_legacy,
46 	Opt_version,
47 	Opt_err,
48 };
49 
50 static const match_table_t tokens = {
51 	{Opt_msize, "msize=%u"},
52 	{Opt_legacy, "noextend"},
53 	{Opt_trans, "trans=%s"},
54 	{Opt_version, "version=%s"},
55 	{Opt_err, NULL},
56 };
57 
58 inline int p9_is_proto_dotl(struct p9_client *clnt)
59 {
60 	return clnt->proto_version == p9_proto_2000L;
61 }
62 EXPORT_SYMBOL(p9_is_proto_dotl);
63 
64 inline int p9_is_proto_dotu(struct p9_client *clnt)
65 {
66 	return clnt->proto_version == p9_proto_2000u;
67 }
68 EXPORT_SYMBOL(p9_is_proto_dotu);
69 
70 int p9_show_client_options(struct seq_file *m, struct p9_client *clnt)
71 {
72 	if (clnt->msize != DEFAULT_MSIZE)
73 		seq_printf(m, ",msize=%u", clnt->msize);
74 	seq_printf(m, ",trans=%s", clnt->trans_mod->name);
75 
76 	switch (clnt->proto_version) {
77 	case p9_proto_legacy:
78 		seq_puts(m, ",noextend");
79 		break;
80 	case p9_proto_2000u:
81 		seq_puts(m, ",version=9p2000.u");
82 		break;
83 	case p9_proto_2000L:
84 		/* Default */
85 		break;
86 	}
87 
88 	if (clnt->trans_mod->show_options)
89 		return clnt->trans_mod->show_options(m, clnt);
90 	return 0;
91 }
92 EXPORT_SYMBOL(p9_show_client_options);
93 
94 /* Some error codes are taken directly from the server replies,
95  * make sure they are valid.
96  */
97 static int safe_errno(int err)
98 {
99 	if (err > 0 || err < -MAX_ERRNO) {
100 		p9_debug(P9_DEBUG_ERROR, "Invalid error code %d\n", err);
101 		return -EPROTO;
102 	}
103 	return err;
104 }
105 
106 /* Interpret mount option for protocol version */
107 static int get_protocol_version(char *s)
108 {
109 	int version = -EINVAL;
110 
111 	if (!strcmp(s, "9p2000")) {
112 		version = p9_proto_legacy;
113 		p9_debug(P9_DEBUG_9P, "Protocol version: Legacy\n");
114 	} else if (!strcmp(s, "9p2000.u")) {
115 		version = p9_proto_2000u;
116 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.u\n");
117 	} else if (!strcmp(s, "9p2000.L")) {
118 		version = p9_proto_2000L;
119 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.L\n");
120 	} else {
121 		pr_info("Unknown protocol version %s\n", s);
122 	}
123 
124 	return version;
125 }
126 
127 /**
128  * parse_opts - parse mount options into client structure
129  * @opts: options string passed from mount
130  * @clnt: existing v9fs client information
131  *
132  * Return 0 upon success, -ERRNO upon failure
133  */
134 
135 static int parse_opts(char *opts, struct p9_client *clnt)
136 {
137 	char *options, *tmp_options;
138 	char *p;
139 	substring_t args[MAX_OPT_ARGS];
140 	int option;
141 	char *s;
142 	int ret = 0;
143 
144 	clnt->proto_version = p9_proto_2000L;
145 	clnt->msize = DEFAULT_MSIZE;
146 
147 	if (!opts)
148 		return 0;
149 
150 	tmp_options = kstrdup(opts, GFP_KERNEL);
151 	if (!tmp_options)
152 		return -ENOMEM;
153 	options = tmp_options;
154 
155 	while ((p = strsep(&options, ",")) != NULL) {
156 		int token, r;
157 
158 		if (!*p)
159 			continue;
160 		token = match_token(p, tokens, args);
161 		switch (token) {
162 		case Opt_msize:
163 			r = match_int(&args[0], &option);
164 			if (r < 0) {
165 				p9_debug(P9_DEBUG_ERROR,
166 					 "integer field, but no integer?\n");
167 				ret = r;
168 				continue;
169 			}
170 			if (option < 4096) {
171 				p9_debug(P9_DEBUG_ERROR,
172 					 "msize should be at least 4k\n");
173 				ret = -EINVAL;
174 				continue;
175 			}
176 			clnt->msize = option;
177 			break;
178 		case Opt_trans:
179 			s = match_strdup(&args[0]);
180 			if (!s) {
181 				ret = -ENOMEM;
182 				p9_debug(P9_DEBUG_ERROR,
183 					 "problem allocating copy of trans arg\n");
184 				goto free_and_return;
185 			}
186 
187 			v9fs_put_trans(clnt->trans_mod);
188 			clnt->trans_mod = v9fs_get_trans_by_name(s);
189 			if (!clnt->trans_mod) {
190 				pr_info("Could not find request transport: %s\n",
191 					s);
192 				ret = -EINVAL;
193 			}
194 			kfree(s);
195 			break;
196 		case Opt_legacy:
197 			clnt->proto_version = p9_proto_legacy;
198 			break;
199 		case Opt_version:
200 			s = match_strdup(&args[0]);
201 			if (!s) {
202 				ret = -ENOMEM;
203 				p9_debug(P9_DEBUG_ERROR,
204 					 "problem allocating copy of version arg\n");
205 				goto free_and_return;
206 			}
207 			r = get_protocol_version(s);
208 			if (r < 0)
209 				ret = r;
210 			else
211 				clnt->proto_version = r;
212 			kfree(s);
213 			break;
214 		default:
215 			continue;
216 		}
217 	}
218 
219 free_and_return:
220 	if (ret)
221 		v9fs_put_trans(clnt->trans_mod);
222 	kfree(tmp_options);
223 	return ret;
224 }
225 
226 static int p9_fcall_init(struct p9_client *c, struct p9_fcall *fc,
227 			 int alloc_msize)
228 {
229 	if (likely(c->fcall_cache) && alloc_msize == c->msize) {
230 		fc->sdata = kmem_cache_alloc(c->fcall_cache, GFP_NOFS);
231 		fc->cache = c->fcall_cache;
232 	} else {
233 		fc->sdata = kmalloc(alloc_msize, GFP_NOFS);
234 		fc->cache = NULL;
235 	}
236 	if (!fc->sdata)
237 		return -ENOMEM;
238 	fc->capacity = alloc_msize;
239 	fc->id = 0;
240 	fc->tag = P9_NOTAG;
241 	return 0;
242 }
243 
244 void p9_fcall_fini(struct p9_fcall *fc)
245 {
246 	/* sdata can be NULL for interrupted requests in trans_rdma,
247 	 * and kmem_cache_free does not do NULL-check for us
248 	 */
249 	if (unlikely(!fc->sdata))
250 		return;
251 
252 	if (fc->cache)
253 		kmem_cache_free(fc->cache, fc->sdata);
254 	else
255 		kfree(fc->sdata);
256 }
257 EXPORT_SYMBOL(p9_fcall_fini);
258 
259 static struct kmem_cache *p9_req_cache;
260 
261 /**
262  * p9_tag_alloc - Allocate a new request.
263  * @c: Client session.
264  * @type: Transaction type.
265  * @t_size: Buffer size for holding this request
266  * (automatic calculation by format template if 0).
267  * @r_size: Buffer size for holding server's reply on this request
268  * (automatic calculation by format template if 0).
269  * @fmt: Format template for assembling 9p request message
270  * (see p9pdu_vwritef).
271  * @ap: Variable arguments to be fed to passed format template
272  * (see p9pdu_vwritef).
273  *
274  * Context: Process context.
275  * Return: Pointer to new request.
276  */
277 static struct p9_req_t *
278 p9_tag_alloc(struct p9_client *c, int8_t type, uint t_size, uint r_size,
279 	      const char *fmt, va_list ap)
280 {
281 	struct p9_req_t *req = kmem_cache_alloc(p9_req_cache, GFP_NOFS);
282 	int alloc_tsize;
283 	int alloc_rsize;
284 	int tag;
285 	va_list apc;
286 
287 	va_copy(apc, ap);
288 	alloc_tsize = min_t(size_t, c->msize,
289 			    t_size ?: p9_msg_buf_size(c, type, fmt, apc));
290 	va_end(apc);
291 
292 	alloc_rsize = min_t(size_t, c->msize,
293 			    r_size ?: p9_msg_buf_size(c, type + 1, fmt, ap));
294 
295 	if (!req)
296 		return ERR_PTR(-ENOMEM);
297 
298 	if (p9_fcall_init(c, &req->tc, alloc_tsize))
299 		goto free_req;
300 	if (p9_fcall_init(c, &req->rc, alloc_rsize))
301 		goto free;
302 
303 	p9pdu_reset(&req->tc);
304 	p9pdu_reset(&req->rc);
305 	req->t_err = 0;
306 	req->status = REQ_STATUS_ALLOC;
307 	/* refcount needs to be set to 0 before inserting into the idr
308 	 * so p9_tag_lookup does not accept a request that is not fully
309 	 * initialized. refcount_set to 2 below will mark request ready.
310 	 */
311 	refcount_set(&req->refcount, 0);
312 	init_waitqueue_head(&req->wq);
313 	INIT_LIST_HEAD(&req->req_list);
314 
315 	idr_preload(GFP_NOFS);
316 	spin_lock_irq(&c->lock);
317 	if (type == P9_TVERSION)
318 		tag = idr_alloc(&c->reqs, req, P9_NOTAG, P9_NOTAG + 1,
319 				GFP_NOWAIT);
320 	else
321 		tag = idr_alloc(&c->reqs, req, 0, P9_NOTAG, GFP_NOWAIT);
322 	req->tc.tag = tag;
323 	spin_unlock_irq(&c->lock);
324 	idr_preload_end();
325 	if (tag < 0)
326 		goto free;
327 
328 	/* Init ref to two because in the general case there is one ref
329 	 * that is put asynchronously by a writer thread, one ref
330 	 * temporarily given by p9_tag_lookup and put by p9_client_cb
331 	 * in the recv thread, and one ref put by p9_req_put in the
332 	 * main thread. The only exception is virtio that does not use
333 	 * p9_tag_lookup but does not have a writer thread either
334 	 * (the write happens synchronously in the request/zc_request
335 	 * callback), so p9_client_cb eats the second ref there
336 	 * as the pointer is duplicated directly by virtqueue_add_sgs()
337 	 */
338 	refcount_set(&req->refcount, 2);
339 
340 	return req;
341 
342 free:
343 	p9_fcall_fini(&req->tc);
344 	p9_fcall_fini(&req->rc);
345 free_req:
346 	kmem_cache_free(p9_req_cache, req);
347 	return ERR_PTR(-ENOMEM);
348 }
349 
350 /**
351  * p9_tag_lookup - Look up a request by tag.
352  * @c: Client session.
353  * @tag: Transaction ID.
354  *
355  * Context: Any context.
356  * Return: A request, or %NULL if there is no request with that tag.
357  */
358 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
359 {
360 	struct p9_req_t *req;
361 
362 	rcu_read_lock();
363 again:
364 	req = idr_find(&c->reqs, tag);
365 	if (req) {
366 		/* We have to be careful with the req found under rcu_read_lock
367 		 * Thanks to SLAB_TYPESAFE_BY_RCU we can safely try to get the
368 		 * ref again without corrupting other data, then check again
369 		 * that the tag matches once we have the ref
370 		 */
371 		if (!p9_req_try_get(req))
372 			goto again;
373 		if (req->tc.tag != tag) {
374 			p9_req_put(c, req);
375 			goto again;
376 		}
377 	}
378 	rcu_read_unlock();
379 
380 	return req;
381 }
382 EXPORT_SYMBOL(p9_tag_lookup);
383 
384 /**
385  * p9_tag_remove - Remove a tag.
386  * @c: Client session.
387  * @r: Request of reference.
388  *
389  * Context: Any context.
390  */
391 static void p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
392 {
393 	unsigned long flags;
394 	u16 tag = r->tc.tag;
395 
396 	p9_debug(P9_DEBUG_MUX, "freeing clnt %p req %p tag: %d\n", c, r, tag);
397 	spin_lock_irqsave(&c->lock, flags);
398 	idr_remove(&c->reqs, tag);
399 	spin_unlock_irqrestore(&c->lock, flags);
400 }
401 
402 int p9_req_put(struct p9_client *c, struct p9_req_t *r)
403 {
404 	if (refcount_dec_and_test(&r->refcount)) {
405 		p9_tag_remove(c, r);
406 
407 		p9_fcall_fini(&r->tc);
408 		p9_fcall_fini(&r->rc);
409 		kmem_cache_free(p9_req_cache, r);
410 		return 1;
411 	}
412 	return 0;
413 }
414 EXPORT_SYMBOL(p9_req_put);
415 
416 /**
417  * p9_tag_cleanup - cleans up tags structure and reclaims resources
418  * @c:  v9fs client struct
419  *
420  * This frees resources associated with the tags structure
421  *
422  */
423 static void p9_tag_cleanup(struct p9_client *c)
424 {
425 	struct p9_req_t *req;
426 	int id;
427 
428 	rcu_read_lock();
429 	idr_for_each_entry(&c->reqs, req, id) {
430 		pr_info("Tag %d still in use\n", id);
431 		if (p9_req_put(c, req) == 0)
432 			pr_warn("Packet with tag %d has still references",
433 				req->tc.tag);
434 	}
435 	rcu_read_unlock();
436 }
437 
438 /**
439  * p9_client_cb - call back from transport to client
440  * @c: client state
441  * @req: request received
442  * @status: request status, one of REQ_STATUS_*
443  *
444  */
445 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
446 {
447 	p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc.tag);
448 
449 	/* This barrier is needed to make sure any change made to req before
450 	 * the status change is visible to another thread
451 	 */
452 	smp_wmb();
453 	WRITE_ONCE(req->status, status);
454 
455 	wake_up(&req->wq);
456 	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
457 	p9_req_put(c, req);
458 }
459 EXPORT_SYMBOL(p9_client_cb);
460 
461 /**
462  * p9_parse_header - parse header arguments out of a packet
463  * @pdu: packet to parse
464  * @size: size of packet
465  * @type: type of request
466  * @tag: tag of packet
467  * @rewind: set if we need to rewind offset afterwards
468  */
469 
470 int
471 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type,
472 		int16_t *tag, int rewind)
473 {
474 	s8 r_type;
475 	s16 r_tag;
476 	s32 r_size;
477 	int offset = pdu->offset;
478 	int err;
479 
480 	pdu->offset = 0;
481 
482 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
483 	if (err)
484 		goto rewind_and_exit;
485 
486 	if (type)
487 		*type = r_type;
488 	if (tag)
489 		*tag = r_tag;
490 	if (size)
491 		*size = r_size;
492 
493 	if (pdu->size != r_size || r_size < 7) {
494 		err = -EINVAL;
495 		goto rewind_and_exit;
496 	}
497 
498 	pdu->id = r_type;
499 	pdu->tag = r_tag;
500 
501 	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
502 		 pdu->size, pdu->id, pdu->tag);
503 
504 rewind_and_exit:
505 	if (rewind)
506 		pdu->offset = offset;
507 	return err;
508 }
509 EXPORT_SYMBOL(p9_parse_header);
510 
511 /**
512  * p9_check_errors - check 9p packet for error return and process it
513  * @c: current client instance
514  * @req: request to parse and check for error conditions
515  *
516  * returns error code if one is discovered, otherwise returns 0
517  *
518  * this will have to be more complicated if we have multiple
519  * error packet types
520  */
521 
522 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
523 {
524 	s8 type;
525 	int err;
526 	int ecode;
527 
528 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
529 	if (req->rc.size > req->rc.capacity && !req->rc.zc) {
530 		pr_err("requested packet size too big: %d does not fit %zu (type=%d)\n",
531 		       req->rc.size, req->rc.capacity, req->rc.id);
532 		return -EIO;
533 	}
534 	/* dump the response from server
535 	 * This should be after check errors which poplulate pdu_fcall.
536 	 */
537 	trace_9p_protocol_dump(c, &req->rc);
538 	if (err) {
539 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
540 		return err;
541 	}
542 	if (type != P9_RERROR && type != P9_RLERROR)
543 		return 0;
544 
545 	if (!p9_is_proto_dotl(c)) {
546 		char *ename = NULL;
547 
548 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
549 				  &ename, &ecode);
550 		if (err) {
551 			kfree(ename);
552 			goto out_err;
553 		}
554 
555 		if (p9_is_proto_dotu(c) && ecode < 512)
556 			err = -ecode;
557 
558 		if (!err) {
559 			err = p9_errstr2errno(ename, strlen(ename));
560 
561 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
562 				 -ecode, ename);
563 		}
564 		kfree(ename);
565 	} else {
566 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
567 		if (err)
568 			goto out_err;
569 		err = -ecode;
570 
571 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
572 	}
573 
574 	return err;
575 
576 out_err:
577 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
578 
579 	return err;
580 }
581 
582 static struct p9_req_t *
583 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
584 
585 /**
586  * p9_client_flush - flush (cancel) a request
587  * @c: client state
588  * @oldreq: request to cancel
589  *
590  * This sents a flush for a particular request and links
591  * the flush request to the original request.  The current
592  * code only supports a single flush request although the protocol
593  * allows for multiple flush requests to be sent for a single request.
594  *
595  */
596 
597 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
598 {
599 	struct p9_req_t *req;
600 	s16 oldtag;
601 	int err;
602 
603 	err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
604 	if (err)
605 		return err;
606 
607 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
608 
609 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
610 	if (IS_ERR(req))
611 		return PTR_ERR(req);
612 
613 	/* if we haven't received a response for oldreq,
614 	 * remove it from the list
615 	 */
616 	if (READ_ONCE(oldreq->status) == REQ_STATUS_SENT) {
617 		if (c->trans_mod->cancelled)
618 			c->trans_mod->cancelled(c, oldreq);
619 	}
620 
621 	p9_req_put(c, req);
622 	return 0;
623 }
624 
625 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
626 					      int8_t type, uint t_size, uint r_size,
627 					      const char *fmt, va_list ap)
628 {
629 	int err;
630 	struct p9_req_t *req;
631 	va_list apc;
632 
633 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
634 
635 	/* we allow for any status other than disconnected */
636 	if (c->status == Disconnected)
637 		return ERR_PTR(-EIO);
638 
639 	/* if status is begin_disconnected we allow only clunk request */
640 	if (c->status == BeginDisconnect && type != P9_TCLUNK)
641 		return ERR_PTR(-EIO);
642 
643 	va_copy(apc, ap);
644 	req = p9_tag_alloc(c, type, t_size, r_size, fmt, apc);
645 	va_end(apc);
646 	if (IS_ERR(req))
647 		return req;
648 
649 	/* marshall the data */
650 	p9pdu_prepare(&req->tc, req->tc.tag, type);
651 	err = p9pdu_vwritef(&req->tc, c->proto_version, fmt, ap);
652 	if (err)
653 		goto reterr;
654 	p9pdu_finalize(c, &req->tc);
655 	trace_9p_client_req(c, type, req->tc.tag);
656 	return req;
657 reterr:
658 	p9_req_put(c, req);
659 	/* We have to put also the 2nd reference as it won't be used */
660 	p9_req_put(c, req);
661 	return ERR_PTR(err);
662 }
663 
664 /**
665  * p9_client_rpc - issue a request and wait for a response
666  * @c: client session
667  * @type: type of request
668  * @fmt: protocol format string (see protocol.c)
669  *
670  * Returns request structure (which client must free using p9_req_put)
671  */
672 
673 static struct p9_req_t *
674 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
675 {
676 	va_list ap;
677 	int sigpending, err;
678 	unsigned long flags;
679 	struct p9_req_t *req;
680 	/* Passing zero for tsize/rsize to p9_client_prepare_req() tells it to
681 	 * auto determine an appropriate (small) request/response size
682 	 * according to actual message data being sent. Currently RDMA
683 	 * transport is excluded from this response message size optimization,
684 	 * as it would not cope with it, due to its pooled response buffers
685 	 * (using an optimized request size for RDMA as well though).
686 	 */
687 	const uint tsize = 0;
688 	const uint rsize = c->trans_mod->pooled_rbuffers ? c->msize : 0;
689 
690 	va_start(ap, fmt);
691 	req = p9_client_prepare_req(c, type, tsize, rsize, fmt, ap);
692 	va_end(ap);
693 	if (IS_ERR(req))
694 		return req;
695 
696 	req->tc.zc = false;
697 	req->rc.zc = false;
698 
699 	if (signal_pending(current)) {
700 		sigpending = 1;
701 		clear_thread_flag(TIF_SIGPENDING);
702 	} else {
703 		sigpending = 0;
704 	}
705 
706 	err = c->trans_mod->request(c, req);
707 	if (err < 0) {
708 		/* write won't happen */
709 		p9_req_put(c, req);
710 		if (err != -ERESTARTSYS && err != -EFAULT)
711 			c->status = Disconnected;
712 		goto recalc_sigpending;
713 	}
714 again:
715 	/* Wait for the response */
716 	err = wait_event_killable(req->wq,
717 				  READ_ONCE(req->status) >= REQ_STATUS_RCVD);
718 
719 	/* Make sure our req is coherent with regard to updates in other
720 	 * threads - echoes to wmb() in the callback
721 	 */
722 	smp_rmb();
723 
724 	if (err == -ERESTARTSYS && c->status == Connected &&
725 	    type == P9_TFLUSH) {
726 		sigpending = 1;
727 		clear_thread_flag(TIF_SIGPENDING);
728 		goto again;
729 	}
730 
731 	if (READ_ONCE(req->status) == REQ_STATUS_ERROR) {
732 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
733 		err = req->t_err;
734 	}
735 	if (err == -ERESTARTSYS && c->status == Connected) {
736 		p9_debug(P9_DEBUG_MUX, "flushing\n");
737 		sigpending = 1;
738 		clear_thread_flag(TIF_SIGPENDING);
739 
740 		if (c->trans_mod->cancel(c, req))
741 			p9_client_flush(c, req);
742 
743 		/* if we received the response anyway, don't signal error */
744 		if (READ_ONCE(req->status) == REQ_STATUS_RCVD)
745 			err = 0;
746 	}
747 recalc_sigpending:
748 	if (sigpending) {
749 		spin_lock_irqsave(&current->sighand->siglock, flags);
750 		recalc_sigpending();
751 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
752 	}
753 	if (err < 0)
754 		goto reterr;
755 
756 	err = p9_check_errors(c, req);
757 	trace_9p_client_res(c, type, req->rc.tag, err);
758 	if (!err)
759 		return req;
760 reterr:
761 	p9_req_put(c, req);
762 	return ERR_PTR(safe_errno(err));
763 }
764 
765 /**
766  * p9_client_zc_rpc - issue a request and wait for a response
767  * @c: client session
768  * @type: type of request
769  * @uidata: destination for zero copy read
770  * @uodata: source for zero copy write
771  * @inlen: read buffer size
772  * @olen: write buffer size
773  * @in_hdrlen: reader header size, This is the size of response protocol data
774  * @fmt: protocol format string (see protocol.c)
775  *
776  * Returns request structure (which client must free using p9_req_put)
777  */
778 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
779 					 struct iov_iter *uidata,
780 					 struct iov_iter *uodata,
781 					 int inlen, int olen, int in_hdrlen,
782 					 const char *fmt, ...)
783 {
784 	va_list ap;
785 	int sigpending, err;
786 	unsigned long flags;
787 	struct p9_req_t *req;
788 
789 	va_start(ap, fmt);
790 	/* We allocate a inline protocol data of only 4k bytes.
791 	 * The actual content is passed in zero-copy fashion.
792 	 */
793 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, P9_ZC_HDR_SZ, fmt, ap);
794 	va_end(ap);
795 	if (IS_ERR(req))
796 		return req;
797 
798 	req->tc.zc = true;
799 	req->rc.zc = true;
800 
801 	if (signal_pending(current)) {
802 		sigpending = 1;
803 		clear_thread_flag(TIF_SIGPENDING);
804 	} else {
805 		sigpending = 0;
806 	}
807 
808 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
809 				       inlen, olen, in_hdrlen);
810 	if (err < 0) {
811 		if (err == -EIO)
812 			c->status = Disconnected;
813 		if (err != -ERESTARTSYS)
814 			goto recalc_sigpending;
815 	}
816 	if (READ_ONCE(req->status) == REQ_STATUS_ERROR) {
817 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
818 		err = req->t_err;
819 	}
820 	if (err == -ERESTARTSYS && c->status == Connected) {
821 		p9_debug(P9_DEBUG_MUX, "flushing\n");
822 		sigpending = 1;
823 		clear_thread_flag(TIF_SIGPENDING);
824 
825 		if (c->trans_mod->cancel(c, req))
826 			p9_client_flush(c, req);
827 
828 		/* if we received the response anyway, don't signal error */
829 		if (READ_ONCE(req->status) == REQ_STATUS_RCVD)
830 			err = 0;
831 	}
832 recalc_sigpending:
833 	if (sigpending) {
834 		spin_lock_irqsave(&current->sighand->siglock, flags);
835 		recalc_sigpending();
836 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
837 	}
838 	if (err < 0)
839 		goto reterr;
840 
841 	err = p9_check_errors(c, req);
842 	trace_9p_client_res(c, type, req->rc.tag, err);
843 	if (!err)
844 		return req;
845 reterr:
846 	p9_req_put(c, req);
847 	return ERR_PTR(safe_errno(err));
848 }
849 
850 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
851 {
852 	int ret;
853 	struct p9_fid *fid;
854 
855 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
856 	fid = kzalloc(sizeof(*fid), GFP_KERNEL);
857 	if (!fid)
858 		return NULL;
859 
860 	fid->mode = -1;
861 	fid->uid = current_fsuid();
862 	fid->clnt = clnt;
863 	refcount_set(&fid->count, 1);
864 
865 	idr_preload(GFP_KERNEL);
866 	spin_lock_irq(&clnt->lock);
867 	ret = idr_alloc_u32(&clnt->fids, fid, &fid->fid, P9_NOFID - 1,
868 			    GFP_NOWAIT);
869 	spin_unlock_irq(&clnt->lock);
870 	idr_preload_end();
871 	if (!ret) {
872 		trace_9p_fid_ref(fid, P9_FID_REF_CREATE);
873 		return fid;
874 	}
875 
876 	kfree(fid);
877 	return NULL;
878 }
879 
880 static void p9_fid_destroy(struct p9_fid *fid)
881 {
882 	struct p9_client *clnt;
883 	unsigned long flags;
884 
885 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
886 	trace_9p_fid_ref(fid, P9_FID_REF_DESTROY);
887 	clnt = fid->clnt;
888 	spin_lock_irqsave(&clnt->lock, flags);
889 	idr_remove(&clnt->fids, fid->fid);
890 	spin_unlock_irqrestore(&clnt->lock, flags);
891 	kfree(fid->rdir);
892 	kfree(fid);
893 }
894 
895 /* We also need to export tracepoint symbols for tracepoint_enabled() */
896 EXPORT_TRACEPOINT_SYMBOL(9p_fid_ref);
897 
898 void do_trace_9p_fid_get(struct p9_fid *fid)
899 {
900 	trace_9p_fid_ref(fid, P9_FID_REF_GET);
901 }
902 EXPORT_SYMBOL(do_trace_9p_fid_get);
903 
904 void do_trace_9p_fid_put(struct p9_fid *fid)
905 {
906 	trace_9p_fid_ref(fid, P9_FID_REF_PUT);
907 }
908 EXPORT_SYMBOL(do_trace_9p_fid_put);
909 
910 static int p9_client_version(struct p9_client *c)
911 {
912 	int err;
913 	struct p9_req_t *req;
914 	char *version = NULL;
915 	int msize;
916 
917 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
918 		 c->msize, c->proto_version);
919 
920 	switch (c->proto_version) {
921 	case p9_proto_2000L:
922 		req = p9_client_rpc(c, P9_TVERSION, "ds",
923 				    c->msize, "9P2000.L");
924 		break;
925 	case p9_proto_2000u:
926 		req = p9_client_rpc(c, P9_TVERSION, "ds",
927 				    c->msize, "9P2000.u");
928 		break;
929 	case p9_proto_legacy:
930 		req = p9_client_rpc(c, P9_TVERSION, "ds",
931 				    c->msize, "9P2000");
932 		break;
933 	default:
934 		return -EINVAL;
935 	}
936 
937 	if (IS_ERR(req))
938 		return PTR_ERR(req);
939 
940 	err = p9pdu_readf(&req->rc, c->proto_version, "ds", &msize, &version);
941 	if (err) {
942 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
943 		trace_9p_protocol_dump(c, &req->rc);
944 		goto error;
945 	}
946 
947 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
948 	if (!strncmp(version, "9P2000.L", 8)) {
949 		c->proto_version = p9_proto_2000L;
950 	} else if (!strncmp(version, "9P2000.u", 8)) {
951 		c->proto_version = p9_proto_2000u;
952 	} else if (!strncmp(version, "9P2000", 6)) {
953 		c->proto_version = p9_proto_legacy;
954 	} else {
955 		p9_debug(P9_DEBUG_ERROR,
956 			 "server returned an unknown version: %s\n", version);
957 		err = -EREMOTEIO;
958 		goto error;
959 	}
960 
961 	if (msize < 4096) {
962 		p9_debug(P9_DEBUG_ERROR,
963 			 "server returned a msize < 4096: %d\n", msize);
964 		err = -EREMOTEIO;
965 		goto error;
966 	}
967 	if (msize < c->msize)
968 		c->msize = msize;
969 
970 error:
971 	kfree(version);
972 	p9_req_put(c, req);
973 
974 	return err;
975 }
976 
977 struct p9_client *p9_client_create(const char *dev_name, char *options)
978 {
979 	int err;
980 	struct p9_client *clnt;
981 	char *client_id;
982 	char *cache_name;
983 
984 	clnt = kmalloc(sizeof(*clnt), GFP_KERNEL);
985 	if (!clnt)
986 		return ERR_PTR(-ENOMEM);
987 
988 	clnt->trans_mod = NULL;
989 	clnt->trans = NULL;
990 	clnt->fcall_cache = NULL;
991 
992 	client_id = utsname()->nodename;
993 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
994 
995 	spin_lock_init(&clnt->lock);
996 	idr_init(&clnt->fids);
997 	idr_init(&clnt->reqs);
998 
999 	err = parse_opts(options, clnt);
1000 	if (err < 0)
1001 		goto free_client;
1002 
1003 	if (!clnt->trans_mod)
1004 		clnt->trans_mod = v9fs_get_default_trans();
1005 
1006 	if (!clnt->trans_mod) {
1007 		err = -EPROTONOSUPPORT;
1008 		p9_debug(P9_DEBUG_ERROR,
1009 			 "No transport defined or default transport\n");
1010 		goto free_client;
1011 	}
1012 
1013 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
1014 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
1015 
1016 	err = clnt->trans_mod->create(clnt, dev_name, options);
1017 	if (err)
1018 		goto put_trans;
1019 
1020 	if (clnt->msize > clnt->trans_mod->maxsize) {
1021 		clnt->msize = clnt->trans_mod->maxsize;
1022 		pr_info("Limiting 'msize' to %d as this is the maximum "
1023 			"supported by transport %s\n",
1024 			clnt->msize, clnt->trans_mod->name
1025 		);
1026 	}
1027 
1028 	if (clnt->msize < 4096) {
1029 		p9_debug(P9_DEBUG_ERROR,
1030 			 "Please specify a msize of at least 4k\n");
1031 		err = -EINVAL;
1032 		goto close_trans;
1033 	}
1034 
1035 	err = p9_client_version(clnt);
1036 	if (err)
1037 		goto close_trans;
1038 
1039 	cache_name = kasprintf(GFP_KERNEL, "9p-fcall-cache-%s", dev_name);
1040 	if (!cache_name) {
1041 		err = -ENOMEM;
1042 		goto close_trans;
1043 	}
1044 
1045 	/* P9_HDRSZ + 4 is the smallest packet header we can have that is
1046 	 * followed by data accessed from userspace by read
1047 	 */
1048 	clnt->fcall_cache =
1049 		kmem_cache_create_usercopy(cache_name, clnt->msize,
1050 					   0, 0, P9_HDRSZ + 4,
1051 					   clnt->msize - (P9_HDRSZ + 4),
1052 					   NULL);
1053 
1054 	kfree(cache_name);
1055 	return clnt;
1056 
1057 close_trans:
1058 	clnt->trans_mod->close(clnt);
1059 put_trans:
1060 	v9fs_put_trans(clnt->trans_mod);
1061 free_client:
1062 	kfree(clnt);
1063 	return ERR_PTR(err);
1064 }
1065 EXPORT_SYMBOL(p9_client_create);
1066 
1067 void p9_client_destroy(struct p9_client *clnt)
1068 {
1069 	struct p9_fid *fid;
1070 	int id;
1071 
1072 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1073 
1074 	if (clnt->trans_mod)
1075 		clnt->trans_mod->close(clnt);
1076 
1077 	v9fs_put_trans(clnt->trans_mod);
1078 
1079 	idr_for_each_entry(&clnt->fids, fid, id) {
1080 		pr_info("Found fid %d not clunked\n", fid->fid);
1081 		p9_fid_destroy(fid);
1082 	}
1083 
1084 	p9_tag_cleanup(clnt);
1085 
1086 	kmem_cache_destroy(clnt->fcall_cache);
1087 	kfree(clnt);
1088 }
1089 EXPORT_SYMBOL(p9_client_destroy);
1090 
1091 void p9_client_disconnect(struct p9_client *clnt)
1092 {
1093 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1094 	clnt->status = Disconnected;
1095 }
1096 EXPORT_SYMBOL(p9_client_disconnect);
1097 
1098 void p9_client_begin_disconnect(struct p9_client *clnt)
1099 {
1100 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1101 	clnt->status = BeginDisconnect;
1102 }
1103 EXPORT_SYMBOL(p9_client_begin_disconnect);
1104 
1105 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1106 				const char *uname, kuid_t n_uname,
1107 				const char *aname)
1108 {
1109 	int err;
1110 	struct p9_req_t *req;
1111 	struct p9_fid *fid;
1112 	struct p9_qid qid;
1113 
1114 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1115 		 afid ? afid->fid : -1, uname, aname);
1116 	fid = p9_fid_create(clnt);
1117 	if (!fid) {
1118 		err = -ENOMEM;
1119 		goto error;
1120 	}
1121 	fid->uid = n_uname;
1122 
1123 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
1124 			    afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
1125 	if (IS_ERR(req)) {
1126 		err = PTR_ERR(req);
1127 		goto error;
1128 	}
1129 
1130 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", &qid);
1131 	if (err) {
1132 		trace_9p_protocol_dump(clnt, &req->rc);
1133 		p9_req_put(clnt, req);
1134 		goto error;
1135 	}
1136 
1137 	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
1138 		 qid.type, qid.path, qid.version);
1139 
1140 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1141 
1142 	p9_req_put(clnt, req);
1143 	return fid;
1144 
1145 error:
1146 	if (fid)
1147 		p9_fid_destroy(fid);
1148 	return ERR_PTR(err);
1149 }
1150 EXPORT_SYMBOL(p9_client_attach);
1151 
1152 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
1153 			      const unsigned char * const *wnames, int clone)
1154 {
1155 	int err;
1156 	struct p9_client *clnt;
1157 	struct p9_fid *fid;
1158 	struct p9_qid *wqids;
1159 	struct p9_req_t *req;
1160 	u16 nwqids, count;
1161 
1162 	wqids = NULL;
1163 	clnt = oldfid->clnt;
1164 	if (clone) {
1165 		fid = p9_fid_create(clnt);
1166 		if (!fid) {
1167 			err = -ENOMEM;
1168 			goto error;
1169 		}
1170 
1171 		fid->uid = oldfid->uid;
1172 	} else {
1173 		fid = oldfid;
1174 	}
1175 
1176 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1177 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1178 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1179 			    nwname, wnames);
1180 	if (IS_ERR(req)) {
1181 		err = PTR_ERR(req);
1182 		goto error;
1183 	}
1184 
1185 	err = p9pdu_readf(&req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1186 	if (err) {
1187 		trace_9p_protocol_dump(clnt, &req->rc);
1188 		p9_req_put(clnt, req);
1189 		goto clunk_fid;
1190 	}
1191 	p9_req_put(clnt, req);
1192 
1193 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1194 
1195 	if (nwqids != nwname) {
1196 		err = -ENOENT;
1197 		goto clunk_fid;
1198 	}
1199 
1200 	for (count = 0; count < nwqids; count++)
1201 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1202 			 count, wqids[count].type,
1203 			 wqids[count].path,
1204 			 wqids[count].version);
1205 
1206 	if (nwname)
1207 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1208 	else
1209 		memmove(&fid->qid, &oldfid->qid, sizeof(struct p9_qid));
1210 
1211 	kfree(wqids);
1212 	return fid;
1213 
1214 clunk_fid:
1215 	kfree(wqids);
1216 	p9_fid_put(fid);
1217 	fid = NULL;
1218 
1219 error:
1220 	if (fid && fid != oldfid)
1221 		p9_fid_destroy(fid);
1222 
1223 	return ERR_PTR(err);
1224 }
1225 EXPORT_SYMBOL(p9_client_walk);
1226 
1227 int p9_client_open(struct p9_fid *fid, int mode)
1228 {
1229 	int err;
1230 	struct p9_client *clnt;
1231 	struct p9_req_t *req;
1232 	struct p9_qid qid;
1233 	int iounit;
1234 
1235 	clnt = fid->clnt;
1236 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1237 		 p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1238 
1239 	if (fid->mode != -1)
1240 		return -EINVAL;
1241 
1242 	if (p9_is_proto_dotl(clnt))
1243 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode & P9L_MODE_MASK);
1244 	else
1245 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode & P9L_MODE_MASK);
1246 	if (IS_ERR(req)) {
1247 		err = PTR_ERR(req);
1248 		goto error;
1249 	}
1250 
1251 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1252 	if (err) {
1253 		trace_9p_protocol_dump(clnt, &req->rc);
1254 		goto free_and_error;
1255 	}
1256 
1257 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1258 		 p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1259 		 qid.path, qid.version, iounit);
1260 
1261 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1262 	fid->mode = mode;
1263 	fid->iounit = iounit;
1264 
1265 free_and_error:
1266 	p9_req_put(clnt, req);
1267 error:
1268 	return err;
1269 }
1270 EXPORT_SYMBOL(p9_client_open);
1271 
1272 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags,
1273 			  u32 mode, kgid_t gid, struct p9_qid *qid)
1274 {
1275 	int err;
1276 	struct p9_client *clnt;
1277 	struct p9_req_t *req;
1278 	int iounit;
1279 
1280 	p9_debug(P9_DEBUG_9P,
1281 		 ">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1282 		 ofid->fid, name, flags, mode,
1283 		 from_kgid(&init_user_ns, gid));
1284 	clnt = ofid->clnt;
1285 
1286 	if (ofid->mode != -1)
1287 		return -EINVAL;
1288 
1289 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1290 			    mode & P9L_MODE_MASK, gid);
1291 	if (IS_ERR(req)) {
1292 		err = PTR_ERR(req);
1293 		goto error;
1294 	}
1295 
1296 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", qid, &iounit);
1297 	if (err) {
1298 		trace_9p_protocol_dump(clnt, &req->rc);
1299 		goto free_and_error;
1300 	}
1301 
1302 	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1303 		 qid->type, qid->path, qid->version, iounit);
1304 
1305 	memmove(&ofid->qid, qid, sizeof(struct p9_qid));
1306 	ofid->mode = flags;
1307 	ofid->iounit = iounit;
1308 
1309 free_and_error:
1310 	p9_req_put(clnt, req);
1311 error:
1312 	return err;
1313 }
1314 EXPORT_SYMBOL(p9_client_create_dotl);
1315 
1316 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1317 		     char *extension)
1318 {
1319 	int err;
1320 	struct p9_client *clnt;
1321 	struct p9_req_t *req;
1322 	struct p9_qid qid;
1323 	int iounit;
1324 
1325 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1326 		 fid->fid, name, perm, mode);
1327 	clnt = fid->clnt;
1328 
1329 	if (fid->mode != -1)
1330 		return -EINVAL;
1331 
1332 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1333 			    mode & P9L_MODE_MASK, extension);
1334 	if (IS_ERR(req)) {
1335 		err = PTR_ERR(req);
1336 		goto error;
1337 	}
1338 
1339 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1340 	if (err) {
1341 		trace_9p_protocol_dump(clnt, &req->rc);
1342 		goto free_and_error;
1343 	}
1344 
1345 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1346 		 qid.type, qid.path, qid.version, iounit);
1347 
1348 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1349 	fid->mode = mode;
1350 	fid->iounit = iounit;
1351 
1352 free_and_error:
1353 	p9_req_put(clnt, req);
1354 error:
1355 	return err;
1356 }
1357 EXPORT_SYMBOL(p9_client_fcreate);
1358 
1359 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1360 		      const char *symtgt, kgid_t gid, struct p9_qid *qid)
1361 {
1362 	int err;
1363 	struct p9_client *clnt;
1364 	struct p9_req_t *req;
1365 
1366 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1367 		 dfid->fid, name, symtgt);
1368 	clnt = dfid->clnt;
1369 
1370 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1371 			    gid);
1372 	if (IS_ERR(req)) {
1373 		err = PTR_ERR(req);
1374 		goto error;
1375 	}
1376 
1377 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
1378 	if (err) {
1379 		trace_9p_protocol_dump(clnt, &req->rc);
1380 		goto free_and_error;
1381 	}
1382 
1383 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1384 		 qid->type, qid->path, qid->version);
1385 
1386 free_and_error:
1387 	p9_req_put(clnt, req);
1388 error:
1389 	return err;
1390 }
1391 EXPORT_SYMBOL(p9_client_symlink);
1392 
1393 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1394 {
1395 	struct p9_client *clnt;
1396 	struct p9_req_t *req;
1397 
1398 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1399 		 dfid->fid, oldfid->fid, newname);
1400 	clnt = dfid->clnt;
1401 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1402 			    newname);
1403 	if (IS_ERR(req))
1404 		return PTR_ERR(req);
1405 
1406 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1407 	p9_req_put(clnt, req);
1408 	return 0;
1409 }
1410 EXPORT_SYMBOL(p9_client_link);
1411 
1412 int p9_client_fsync(struct p9_fid *fid, int datasync)
1413 {
1414 	int err = 0;
1415 	struct p9_client *clnt;
1416 	struct p9_req_t *req;
1417 
1418 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1419 		 fid->fid, datasync);
1420 	clnt = fid->clnt;
1421 
1422 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1423 	if (IS_ERR(req)) {
1424 		err = PTR_ERR(req);
1425 		goto error;
1426 	}
1427 
1428 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1429 
1430 	p9_req_put(clnt, req);
1431 
1432 error:
1433 	return err;
1434 }
1435 EXPORT_SYMBOL(p9_client_fsync);
1436 
1437 int p9_client_clunk(struct p9_fid *fid)
1438 {
1439 	int err = 0;
1440 	struct p9_client *clnt;
1441 	struct p9_req_t *req;
1442 	int retries = 0;
1443 
1444 again:
1445 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n",
1446 		 fid->fid, retries);
1447 	clnt = fid->clnt;
1448 
1449 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1450 	if (IS_ERR(req)) {
1451 		err = PTR_ERR(req);
1452 		goto error;
1453 	}
1454 
1455 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1456 
1457 	p9_req_put(clnt, req);
1458 error:
1459 	/* Fid is not valid even after a failed clunk
1460 	 * If interrupted, retry once then give up and
1461 	 * leak fid until umount.
1462 	 */
1463 	if (err == -ERESTARTSYS) {
1464 		if (retries++ == 0)
1465 			goto again;
1466 	} else {
1467 		p9_fid_destroy(fid);
1468 	}
1469 	return err;
1470 }
1471 EXPORT_SYMBOL(p9_client_clunk);
1472 
1473 int p9_client_remove(struct p9_fid *fid)
1474 {
1475 	int err = 0;
1476 	struct p9_client *clnt;
1477 	struct p9_req_t *req;
1478 
1479 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1480 	clnt = fid->clnt;
1481 
1482 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1483 	if (IS_ERR(req)) {
1484 		err = PTR_ERR(req);
1485 		goto error;
1486 	}
1487 
1488 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1489 
1490 	p9_req_put(clnt, req);
1491 error:
1492 	if (err == -ERESTARTSYS)
1493 		p9_fid_put(fid);
1494 	else
1495 		p9_fid_destroy(fid);
1496 	return err;
1497 }
1498 EXPORT_SYMBOL(p9_client_remove);
1499 
1500 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1501 {
1502 	int err = 0;
1503 	struct p9_req_t *req;
1504 	struct p9_client *clnt;
1505 
1506 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1507 		 dfid->fid, name, flags);
1508 
1509 	clnt = dfid->clnt;
1510 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1511 	if (IS_ERR(req)) {
1512 		err = PTR_ERR(req);
1513 		goto error;
1514 	}
1515 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1516 
1517 	p9_req_put(clnt, req);
1518 error:
1519 	return err;
1520 }
1521 EXPORT_SYMBOL(p9_client_unlinkat);
1522 
1523 int
1524 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1525 {
1526 	int total = 0;
1527 	*err = 0;
1528 
1529 	while (iov_iter_count(to)) {
1530 		int count;
1531 
1532 		count = p9_client_read_once(fid, offset, to, err);
1533 		if (!count || *err)
1534 			break;
1535 		offset += count;
1536 		total += count;
1537 	}
1538 	return total;
1539 }
1540 EXPORT_SYMBOL(p9_client_read);
1541 
1542 int
1543 p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
1544 		    int *err)
1545 {
1546 	struct p9_client *clnt = fid->clnt;
1547 	struct p9_req_t *req;
1548 	int count = iov_iter_count(to);
1549 	int rsize, received, non_zc = 0;
1550 	char *dataptr;
1551 
1552 	*err = 0;
1553 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %zu\n",
1554 		 fid->fid, offset, iov_iter_count(to));
1555 
1556 	rsize = fid->iounit;
1557 	if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1558 		rsize = clnt->msize - P9_IOHDRSZ;
1559 
1560 	if (count < rsize)
1561 		rsize = count;
1562 
1563 	/* Don't bother zerocopy for small IO (< 1024) */
1564 	if (clnt->trans_mod->zc_request && rsize > 1024) {
1565 		/* response header len is 11
1566 		 * PDU Header(7) + IO Size (4)
1567 		 */
1568 		req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1569 				       0, 11, "dqd", fid->fid,
1570 				       offset, rsize);
1571 	} else {
1572 		non_zc = 1;
1573 		req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1574 				    rsize);
1575 	}
1576 	if (IS_ERR(req)) {
1577 		*err = PTR_ERR(req);
1578 		if (!non_zc)
1579 			iov_iter_revert(to, count - iov_iter_count(to));
1580 		return 0;
1581 	}
1582 
1583 	*err = p9pdu_readf(&req->rc, clnt->proto_version,
1584 			   "D", &received, &dataptr);
1585 	if (*err) {
1586 		if (!non_zc)
1587 			iov_iter_revert(to, count - iov_iter_count(to));
1588 		trace_9p_protocol_dump(clnt, &req->rc);
1589 		p9_req_put(clnt, req);
1590 		return 0;
1591 	}
1592 	if (rsize < received) {
1593 		pr_err("bogus RREAD count (%d > %d)\n", received, rsize);
1594 		received = rsize;
1595 	}
1596 
1597 	p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", received);
1598 
1599 	if (non_zc) {
1600 		int n = copy_to_iter(dataptr, received, to);
1601 
1602 		if (n != received) {
1603 			*err = -EFAULT;
1604 			p9_req_put(clnt, req);
1605 			return n;
1606 		}
1607 	} else {
1608 		iov_iter_revert(to, count - received - iov_iter_count(to));
1609 	}
1610 	p9_req_put(clnt, req);
1611 	return received;
1612 }
1613 EXPORT_SYMBOL(p9_client_read_once);
1614 
1615 int
1616 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1617 {
1618 	struct p9_client *clnt = fid->clnt;
1619 	struct p9_req_t *req;
1620 	int total = 0;
1621 	*err = 0;
1622 
1623 	while (iov_iter_count(from)) {
1624 		int count = iov_iter_count(from);
1625 		int rsize = fid->iounit;
1626 		int written;
1627 
1628 		if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1629 			rsize = clnt->msize - P9_IOHDRSZ;
1630 
1631 		if (count < rsize)
1632 			rsize = count;
1633 
1634 		p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %d (/%d)\n",
1635 			 fid->fid, offset, rsize, count);
1636 
1637 		/* Don't bother zerocopy for small IO (< 1024) */
1638 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1639 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1640 					       rsize, P9_ZC_HDR_SZ, "dqd",
1641 					       fid->fid, offset, rsize);
1642 		} else {
1643 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1644 					    offset, rsize, from);
1645 		}
1646 		if (IS_ERR(req)) {
1647 			iov_iter_revert(from, count - iov_iter_count(from));
1648 			*err = PTR_ERR(req);
1649 			break;
1650 		}
1651 
1652 		*err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &written);
1653 		if (*err) {
1654 			iov_iter_revert(from, count - iov_iter_count(from));
1655 			trace_9p_protocol_dump(clnt, &req->rc);
1656 			p9_req_put(clnt, req);
1657 			break;
1658 		}
1659 		if (rsize < written) {
1660 			pr_err("bogus RWRITE count (%d > %d)\n", written, rsize);
1661 			written = rsize;
1662 		}
1663 
1664 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", written);
1665 
1666 		p9_req_put(clnt, req);
1667 		iov_iter_revert(from, count - written - iov_iter_count(from));
1668 		total += written;
1669 		offset += written;
1670 	}
1671 	return total;
1672 }
1673 EXPORT_SYMBOL(p9_client_write);
1674 
1675 void
1676 p9_client_write_subreq(struct netfs_io_subrequest *subreq)
1677 {
1678 	struct netfs_io_request *wreq = subreq->rreq;
1679 	struct p9_fid *fid = wreq->netfs_priv;
1680 	struct p9_client *clnt = fid->clnt;
1681 	struct p9_req_t *req;
1682 	unsigned long long start = subreq->start + subreq->transferred;
1683 	int written, len = subreq->len - subreq->transferred;
1684 	int err;
1685 
1686 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu len %d\n",
1687 		 fid->fid, start, len);
1688 
1689 	/* Don't bother zerocopy for small IO (< 1024) */
1690 	if (clnt->trans_mod->zc_request && len > 1024) {
1691 		req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, &subreq->io_iter,
1692 				       0, wreq->len, P9_ZC_HDR_SZ, "dqd",
1693 				       fid->fid, start, len);
1694 	} else {
1695 		req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1696 				    start, len, &subreq->io_iter);
1697 	}
1698 	if (IS_ERR(req)) {
1699 		netfs_write_subrequest_terminated(subreq, PTR_ERR(req), false);
1700 		return;
1701 	}
1702 
1703 	err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &written);
1704 	if (err) {
1705 		trace_9p_protocol_dump(clnt, &req->rc);
1706 		p9_req_put(clnt, req);
1707 		netfs_write_subrequest_terminated(subreq, err, false);
1708 		return;
1709 	}
1710 
1711 	if (written > len) {
1712 		pr_err("bogus RWRITE count (%d > %u)\n", written, len);
1713 		written = len;
1714 	}
1715 
1716 	p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", len);
1717 
1718 	p9_req_put(clnt, req);
1719 	netfs_write_subrequest_terminated(subreq, written, false);
1720 }
1721 EXPORT_SYMBOL(p9_client_write_subreq);
1722 
1723 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1724 {
1725 	int err;
1726 	struct p9_client *clnt;
1727 	struct p9_wstat *ret;
1728 	struct p9_req_t *req;
1729 	u16 ignored;
1730 
1731 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1732 
1733 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1734 	if (!ret)
1735 		return ERR_PTR(-ENOMEM);
1736 
1737 	clnt = fid->clnt;
1738 
1739 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1740 	if (IS_ERR(req)) {
1741 		err = PTR_ERR(req);
1742 		goto error;
1743 	}
1744 
1745 	err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
1746 	if (err) {
1747 		trace_9p_protocol_dump(clnt, &req->rc);
1748 		p9_req_put(clnt, req);
1749 		goto error;
1750 	}
1751 
1752 	p9_debug(P9_DEBUG_9P,
1753 		 "<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1754 		 "<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1755 		 "<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1756 		 "<<<    uid=%d gid=%d n_muid=%d\n",
1757 		 ret->size, ret->type, ret->dev, ret->qid.type, ret->qid.path,
1758 		 ret->qid.version, ret->mode,
1759 		 ret->atime, ret->mtime, ret->length,
1760 		 ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1761 		 from_kuid(&init_user_ns, ret->n_uid),
1762 		 from_kgid(&init_user_ns, ret->n_gid),
1763 		 from_kuid(&init_user_ns, ret->n_muid));
1764 
1765 	p9_req_put(clnt, req);
1766 	return ret;
1767 
1768 error:
1769 	kfree(ret);
1770 	return ERR_PTR(err);
1771 }
1772 EXPORT_SYMBOL(p9_client_stat);
1773 
1774 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1775 					    u64 request_mask)
1776 {
1777 	int err;
1778 	struct p9_client *clnt;
1779 	struct p9_stat_dotl *ret;
1780 	struct p9_req_t *req;
1781 
1782 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1783 		 fid->fid, request_mask);
1784 
1785 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1786 	if (!ret)
1787 		return ERR_PTR(-ENOMEM);
1788 
1789 	clnt = fid->clnt;
1790 
1791 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1792 	if (IS_ERR(req)) {
1793 		err = PTR_ERR(req);
1794 		goto error;
1795 	}
1796 
1797 	err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
1798 	if (err) {
1799 		trace_9p_protocol_dump(clnt, &req->rc);
1800 		p9_req_put(clnt, req);
1801 		goto error;
1802 	}
1803 
1804 	p9_debug(P9_DEBUG_9P, "<<< RGETATTR st_result_mask=%lld\n"
1805 		 "<<< qid=%x.%llx.%x\n"
1806 		 "<<< st_mode=%8.8x st_nlink=%llu\n"
1807 		 "<<< st_uid=%d st_gid=%d\n"
1808 		 "<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1809 		 "<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1810 		 "<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1811 		 "<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1812 		 "<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1813 		 "<<< st_gen=%lld st_data_version=%lld\n",
1814 		 ret->st_result_mask,
1815 		 ret->qid.type, ret->qid.path, ret->qid.version,
1816 		 ret->st_mode, ret->st_nlink,
1817 		 from_kuid(&init_user_ns, ret->st_uid),
1818 		 from_kgid(&init_user_ns, ret->st_gid),
1819 		 ret->st_rdev, ret->st_size, ret->st_blksize, ret->st_blocks,
1820 		 ret->st_atime_sec, ret->st_atime_nsec,
1821 		 ret->st_mtime_sec, ret->st_mtime_nsec,
1822 		 ret->st_ctime_sec, ret->st_ctime_nsec,
1823 		 ret->st_btime_sec, ret->st_btime_nsec,
1824 		 ret->st_gen, ret->st_data_version);
1825 
1826 	p9_req_put(clnt, req);
1827 	return ret;
1828 
1829 error:
1830 	kfree(ret);
1831 	return ERR_PTR(err);
1832 }
1833 EXPORT_SYMBOL(p9_client_getattr_dotl);
1834 
1835 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1836 {
1837 	int ret;
1838 
1839 	/* NOTE: size shouldn't include its own length */
1840 	/* size[2] type[2] dev[4] qid[13] */
1841 	/* mode[4] atime[4] mtime[4] length[8]*/
1842 	/* name[s] uid[s] gid[s] muid[s] */
1843 	ret = 2 + 4 + 13 + 4 + 4 + 4 + 8 + 2 + 2 + 2 + 2;
1844 
1845 	if (wst->name)
1846 		ret += strlen(wst->name);
1847 	if (wst->uid)
1848 		ret += strlen(wst->uid);
1849 	if (wst->gid)
1850 		ret += strlen(wst->gid);
1851 	if (wst->muid)
1852 		ret += strlen(wst->muid);
1853 
1854 	if (proto_version == p9_proto_2000u ||
1855 	    proto_version == p9_proto_2000L) {
1856 		/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1857 		ret += 2 + 4 + 4 + 4;
1858 		if (wst->extension)
1859 			ret += strlen(wst->extension);
1860 	}
1861 
1862 	return ret;
1863 }
1864 
1865 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1866 {
1867 	int err = 0;
1868 	struct p9_req_t *req;
1869 	struct p9_client *clnt;
1870 
1871 	clnt = fid->clnt;
1872 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1873 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n",
1874 		 fid->fid);
1875 	p9_debug(P9_DEBUG_9P,
1876 		 "     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1877 		 "     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1878 		 "     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1879 		 "     uid=%d gid=%d n_muid=%d\n",
1880 		 wst->size, wst->type, wst->dev, wst->qid.type,
1881 		 wst->qid.path, wst->qid.version,
1882 		 wst->mode, wst->atime, wst->mtime, wst->length,
1883 		 wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1884 		 from_kuid(&init_user_ns, wst->n_uid),
1885 		 from_kgid(&init_user_ns, wst->n_gid),
1886 		 from_kuid(&init_user_ns, wst->n_muid));
1887 
1888 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS",
1889 			    fid->fid, wst->size + 2, wst);
1890 	if (IS_ERR(req)) {
1891 		err = PTR_ERR(req);
1892 		goto error;
1893 	}
1894 
1895 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1896 
1897 	p9_req_put(clnt, req);
1898 error:
1899 	return err;
1900 }
1901 EXPORT_SYMBOL(p9_client_wstat);
1902 
1903 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1904 {
1905 	int err = 0;
1906 	struct p9_req_t *req;
1907 	struct p9_client *clnt;
1908 
1909 	clnt = fid->clnt;
1910 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1911 	p9_debug(P9_DEBUG_9P, "    valid=%x mode=%x uid=%d gid=%d size=%lld\n",
1912 		 p9attr->valid, p9attr->mode,
1913 		 from_kuid(&init_user_ns, p9attr->uid),
1914 		 from_kgid(&init_user_ns, p9attr->gid),
1915 		 p9attr->size);
1916 	p9_debug(P9_DEBUG_9P, "    atime_sec=%lld atime_nsec=%lld\n",
1917 		 p9attr->atime_sec, p9attr->atime_nsec);
1918 	p9_debug(P9_DEBUG_9P, "    mtime_sec=%lld mtime_nsec=%lld\n",
1919 		 p9attr->mtime_sec, p9attr->mtime_nsec);
1920 
1921 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1922 
1923 	if (IS_ERR(req)) {
1924 		err = PTR_ERR(req);
1925 		goto error;
1926 	}
1927 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1928 	p9_req_put(clnt, req);
1929 error:
1930 	return err;
1931 }
1932 EXPORT_SYMBOL(p9_client_setattr);
1933 
1934 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1935 {
1936 	int err;
1937 	struct p9_req_t *req;
1938 	struct p9_client *clnt;
1939 
1940 	clnt = fid->clnt;
1941 
1942 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1943 
1944 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1945 	if (IS_ERR(req)) {
1946 		err = PTR_ERR(req);
1947 		goto error;
1948 	}
1949 
1950 	err = p9pdu_readf(&req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1951 			  &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1952 			  &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1953 	if (err) {
1954 		trace_9p_protocol_dump(clnt, &req->rc);
1955 		p9_req_put(clnt, req);
1956 		goto error;
1957 	}
1958 
1959 	p9_debug(P9_DEBUG_9P,
1960 		 "<<< RSTATFS fid %d type 0x%x bsize %u blocks %llu bfree %llu bavail %llu files %llu ffree %llu fsid %llu namelen %u\n",
1961 		 fid->fid, sb->type, sb->bsize, sb->blocks, sb->bfree,
1962 		 sb->bavail, sb->files, sb->ffree, sb->fsid, sb->namelen);
1963 
1964 	p9_req_put(clnt, req);
1965 error:
1966 	return err;
1967 }
1968 EXPORT_SYMBOL(p9_client_statfs);
1969 
1970 int p9_client_rename(struct p9_fid *fid,
1971 		     struct p9_fid *newdirfid, const char *name)
1972 {
1973 	int err = 0;
1974 	struct p9_req_t *req;
1975 	struct p9_client *clnt;
1976 
1977 	clnt = fid->clnt;
1978 
1979 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1980 		 fid->fid, newdirfid->fid, name);
1981 
1982 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1983 			    newdirfid->fid, name);
1984 	if (IS_ERR(req)) {
1985 		err = PTR_ERR(req);
1986 		goto error;
1987 	}
1988 
1989 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1990 
1991 	p9_req_put(clnt, req);
1992 error:
1993 	return err;
1994 }
1995 EXPORT_SYMBOL(p9_client_rename);
1996 
1997 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
1998 		       struct p9_fid *newdirfid, const char *new_name)
1999 {
2000 	int err = 0;
2001 	struct p9_req_t *req;
2002 	struct p9_client *clnt;
2003 
2004 	clnt = olddirfid->clnt;
2005 
2006 	p9_debug(P9_DEBUG_9P,
2007 		 ">>> TRENAMEAT olddirfid %d old name %s newdirfid %d new name %s\n",
2008 		 olddirfid->fid, old_name, newdirfid->fid, new_name);
2009 
2010 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
2011 			    old_name, newdirfid->fid, new_name);
2012 	if (IS_ERR(req)) {
2013 		err = PTR_ERR(req);
2014 		goto error;
2015 	}
2016 
2017 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
2018 		 newdirfid->fid, new_name);
2019 
2020 	p9_req_put(clnt, req);
2021 error:
2022 	return err;
2023 }
2024 EXPORT_SYMBOL(p9_client_renameat);
2025 
2026 /* An xattrwalk without @attr_name gives the fid for the lisxattr namespace
2027  */
2028 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
2029 				   const char *attr_name, u64 *attr_size)
2030 {
2031 	int err;
2032 	struct p9_req_t *req;
2033 	struct p9_client *clnt;
2034 	struct p9_fid *attr_fid;
2035 
2036 	clnt = file_fid->clnt;
2037 	attr_fid = p9_fid_create(clnt);
2038 	if (!attr_fid) {
2039 		err = -ENOMEM;
2040 		goto error;
2041 	}
2042 	p9_debug(P9_DEBUG_9P,
2043 		 ">>> TXATTRWALK file_fid %d, attr_fid %d name '%s'\n",
2044 		 file_fid->fid, attr_fid->fid, attr_name);
2045 
2046 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
2047 			    file_fid->fid, attr_fid->fid, attr_name);
2048 	if (IS_ERR(req)) {
2049 		err = PTR_ERR(req);
2050 		goto error;
2051 	}
2052 	err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
2053 	if (err) {
2054 		trace_9p_protocol_dump(clnt, &req->rc);
2055 		p9_req_put(clnt, req);
2056 		goto clunk_fid;
2057 	}
2058 	p9_req_put(clnt, req);
2059 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
2060 		 attr_fid->fid, *attr_size);
2061 	return attr_fid;
2062 clunk_fid:
2063 	p9_fid_put(attr_fid);
2064 	attr_fid = NULL;
2065 error:
2066 	if (attr_fid && attr_fid != file_fid)
2067 		p9_fid_destroy(attr_fid);
2068 
2069 	return ERR_PTR(err);
2070 }
2071 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
2072 
2073 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
2074 			  u64 attr_size, int flags)
2075 {
2076 	int err = 0;
2077 	struct p9_req_t *req;
2078 	struct p9_client *clnt;
2079 
2080 	p9_debug(P9_DEBUG_9P,
2081 		 ">>> TXATTRCREATE fid %d name  %s size %llu flag %d\n",
2082 		 fid->fid, name, attr_size, flags);
2083 	clnt = fid->clnt;
2084 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
2085 			    fid->fid, name, attr_size, flags);
2086 	if (IS_ERR(req)) {
2087 		err = PTR_ERR(req);
2088 		goto error;
2089 	}
2090 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
2091 	p9_req_put(clnt, req);
2092 error:
2093 	return err;
2094 }
2095 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
2096 
2097 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
2098 {
2099 	int err, rsize, non_zc = 0;
2100 	struct p9_client *clnt;
2101 	struct p9_req_t *req;
2102 	char *dataptr;
2103 	struct kvec kv = {.iov_base = data, .iov_len = count};
2104 	struct iov_iter to;
2105 
2106 	iov_iter_kvec(&to, ITER_DEST, &kv, 1, count);
2107 
2108 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
2109 		 fid->fid, offset, count);
2110 
2111 	clnt = fid->clnt;
2112 
2113 	rsize = fid->iounit;
2114 	if (!rsize || rsize > clnt->msize - P9_READDIRHDRSZ)
2115 		rsize = clnt->msize - P9_READDIRHDRSZ;
2116 
2117 	if (count < rsize)
2118 		rsize = count;
2119 
2120 	/* Don't bother zerocopy for small IO (< 1024) */
2121 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2122 		/* response header len is 11
2123 		 * PDU Header(7) + IO Size (4)
2124 		 */
2125 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2126 				       11, "dqd", fid->fid, offset, rsize);
2127 	} else {
2128 		non_zc = 1;
2129 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2130 				    offset, rsize);
2131 	}
2132 	if (IS_ERR(req)) {
2133 		err = PTR_ERR(req);
2134 		goto error;
2135 	}
2136 
2137 	err = p9pdu_readf(&req->rc, clnt->proto_version, "D", &count, &dataptr);
2138 	if (err) {
2139 		trace_9p_protocol_dump(clnt, &req->rc);
2140 		goto free_and_error;
2141 	}
2142 	if (rsize < count) {
2143 		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
2144 		count = rsize;
2145 	}
2146 
2147 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
2148 
2149 	if (non_zc)
2150 		memmove(data, dataptr, count);
2151 
2152 	p9_req_put(clnt, req);
2153 	return count;
2154 
2155 free_and_error:
2156 	p9_req_put(clnt, req);
2157 error:
2158 	return err;
2159 }
2160 EXPORT_SYMBOL(p9_client_readdir);
2161 
2162 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2163 			 dev_t rdev, kgid_t gid, struct p9_qid *qid)
2164 {
2165 	int err;
2166 	struct p9_client *clnt;
2167 	struct p9_req_t *req;
2168 
2169 	clnt = fid->clnt;
2170 	p9_debug(P9_DEBUG_9P,
2171 		 ">>> TMKNOD fid %d name %s mode %d major %d minor %d\n",
2172 		 fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2173 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2174 			    MAJOR(rdev), MINOR(rdev), gid);
2175 	if (IS_ERR(req))
2176 		return PTR_ERR(req);
2177 
2178 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2179 	if (err) {
2180 		trace_9p_protocol_dump(clnt, &req->rc);
2181 		goto error;
2182 	}
2183 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n",
2184 		 qid->type, qid->path, qid->version);
2185 
2186 error:
2187 	p9_req_put(clnt, req);
2188 	return err;
2189 }
2190 EXPORT_SYMBOL(p9_client_mknod_dotl);
2191 
2192 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2193 			 kgid_t gid, struct p9_qid *qid)
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, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
2201 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
2202 	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg",
2203 			    fid->fid, name, mode, gid);
2204 	if (IS_ERR(req))
2205 		return PTR_ERR(req);
2206 
2207 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2208 	if (err) {
2209 		trace_9p_protocol_dump(clnt, &req->rc);
2210 		goto error;
2211 	}
2212 	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
2213 		 qid->path, qid->version);
2214 
2215 error:
2216 	p9_req_put(clnt, req);
2217 	return err;
2218 }
2219 EXPORT_SYMBOL(p9_client_mkdir_dotl);
2220 
2221 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
2222 {
2223 	int err;
2224 	struct p9_client *clnt;
2225 	struct p9_req_t *req;
2226 
2227 	clnt = fid->clnt;
2228 	p9_debug(P9_DEBUG_9P,
2229 		 ">>> TLOCK fid %d type %i flags %d start %lld length %lld proc_id %d client_id %s\n",
2230 		 fid->fid, flock->type, flock->flags, flock->start,
2231 		 flock->length, flock->proc_id, flock->client_id);
2232 
2233 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2234 			    flock->flags, flock->start, flock->length,
2235 			    flock->proc_id, flock->client_id);
2236 
2237 	if (IS_ERR(req))
2238 		return PTR_ERR(req);
2239 
2240 	err = p9pdu_readf(&req->rc, clnt->proto_version, "b", status);
2241 	if (err) {
2242 		trace_9p_protocol_dump(clnt, &req->rc);
2243 		goto error;
2244 	}
2245 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2246 error:
2247 	p9_req_put(clnt, req);
2248 	return err;
2249 }
2250 EXPORT_SYMBOL(p9_client_lock_dotl);
2251 
2252 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2253 {
2254 	int err;
2255 	struct p9_client *clnt;
2256 	struct p9_req_t *req;
2257 
2258 	clnt = fid->clnt;
2259 	p9_debug(P9_DEBUG_9P,
2260 		 ">>> TGETLOCK fid %d, type %i start %lld length %lld proc_id %d client_id %s\n",
2261 		 fid->fid, glock->type, glock->start, glock->length,
2262 		 glock->proc_id, glock->client_id);
2263 
2264 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,
2265 			    glock->type, glock->start, glock->length,
2266 			    glock->proc_id, glock->client_id);
2267 
2268 	if (IS_ERR(req))
2269 		return PTR_ERR(req);
2270 
2271 	err = p9pdu_readf(&req->rc, clnt->proto_version, "bqqds", &glock->type,
2272 			  &glock->start, &glock->length, &glock->proc_id,
2273 			  &glock->client_id);
2274 	if (err) {
2275 		trace_9p_protocol_dump(clnt, &req->rc);
2276 		goto error;
2277 	}
2278 	p9_debug(P9_DEBUG_9P,
2279 		 "<<< RGETLOCK type %i start %lld length %lld proc_id %d client_id %s\n",
2280 		 glock->type, glock->start, glock->length,
2281 		 glock->proc_id, glock->client_id);
2282 error:
2283 	p9_req_put(clnt, req);
2284 	return err;
2285 }
2286 EXPORT_SYMBOL(p9_client_getlock_dotl);
2287 
2288 int p9_client_readlink(struct p9_fid *fid, char **target)
2289 {
2290 	int err;
2291 	struct p9_client *clnt;
2292 	struct p9_req_t *req;
2293 
2294 	clnt = fid->clnt;
2295 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2296 
2297 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2298 	if (IS_ERR(req))
2299 		return PTR_ERR(req);
2300 
2301 	err = p9pdu_readf(&req->rc, clnt->proto_version, "s", target);
2302 	if (err) {
2303 		trace_9p_protocol_dump(clnt, &req->rc);
2304 		goto error;
2305 	}
2306 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2307 error:
2308 	p9_req_put(clnt, req);
2309 	return err;
2310 }
2311 EXPORT_SYMBOL(p9_client_readlink);
2312 
2313 int __init p9_client_init(void)
2314 {
2315 	p9_req_cache = KMEM_CACHE(p9_req_t, SLAB_TYPESAFE_BY_RCU);
2316 	return p9_req_cache ? 0 : -ENOMEM;
2317 }
2318 
2319 void __exit p9_client_exit(void)
2320 {
2321 	kmem_cache_destroy(p9_req_cache);
2322 }
2323