xref: /linux/net/9p/client.c (revision e21d451a82f39e91b7635c4fc3ff5ac082873ec3)
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 		if (!fc->sdata && c->trans_mod->supports_vmalloc) {
233 			fc->sdata = kvmalloc(alloc_msize, GFP_NOFS);
234 			fc->cache = NULL;
235 		}
236 	} else {
237 		if (c->trans_mod->supports_vmalloc)
238 			fc->sdata = kvmalloc(alloc_msize, GFP_NOFS);
239 		else
240 			fc->sdata = kmalloc(alloc_msize, GFP_NOFS);
241 		fc->cache = NULL;
242 	}
243 	if (!fc->sdata)
244 		return -ENOMEM;
245 	fc->capacity = alloc_msize;
246 	fc->id = 0;
247 	fc->tag = P9_NOTAG;
248 	return 0;
249 }
250 
251 void p9_fcall_fini(struct p9_fcall *fc)
252 {
253 	/* sdata can be NULL for interrupted requests in trans_rdma,
254 	 * and kmem_cache_free does not do NULL-check for us
255 	 */
256 	if (unlikely(!fc->sdata))
257 		return;
258 
259 	if (fc->cache)
260 		kmem_cache_free(fc->cache, fc->sdata);
261 	else
262 		kvfree(fc->sdata);
263 }
264 EXPORT_SYMBOL(p9_fcall_fini);
265 
266 static struct kmem_cache *p9_req_cache;
267 
268 /**
269  * p9_tag_alloc - Allocate a new request.
270  * @c: Client session.
271  * @type: Transaction type.
272  * @t_size: Buffer size for holding this request
273  * (automatic calculation by format template if 0).
274  * @r_size: Buffer size for holding server's reply on this request
275  * (automatic calculation by format template if 0).
276  * @fmt: Format template for assembling 9p request message
277  * (see p9pdu_vwritef).
278  * @ap: Variable arguments to be fed to passed format template
279  * (see p9pdu_vwritef).
280  *
281  * Context: Process context.
282  * Return: Pointer to new request.
283  */
284 static struct p9_req_t *
285 p9_tag_alloc(struct p9_client *c, int8_t type, uint t_size, uint r_size,
286 	      const char *fmt, va_list ap)
287 {
288 	struct p9_req_t *req = kmem_cache_alloc(p9_req_cache, GFP_NOFS);
289 	int alloc_tsize;
290 	int alloc_rsize;
291 	int tag;
292 	va_list apc;
293 
294 	va_copy(apc, ap);
295 	alloc_tsize = min_t(size_t, c->msize,
296 			    t_size ?: p9_msg_buf_size(c, type, fmt, apc));
297 	va_end(apc);
298 
299 	alloc_rsize = min_t(size_t, c->msize,
300 			    r_size ?: p9_msg_buf_size(c, type + 1, fmt, ap));
301 
302 	if (!req)
303 		return ERR_PTR(-ENOMEM);
304 
305 	if (p9_fcall_init(c, &req->tc, alloc_tsize))
306 		goto free_req;
307 	if (p9_fcall_init(c, &req->rc, alloc_rsize))
308 		goto free;
309 
310 	p9pdu_reset(&req->tc);
311 	p9pdu_reset(&req->rc);
312 	req->t_err = 0;
313 	req->status = REQ_STATUS_ALLOC;
314 	/* refcount needs to be set to 0 before inserting into the idr
315 	 * so p9_tag_lookup does not accept a request that is not fully
316 	 * initialized. refcount_set to 2 below will mark request ready.
317 	 */
318 	refcount_set(&req->refcount, 0);
319 	init_waitqueue_head(&req->wq);
320 	INIT_LIST_HEAD(&req->req_list);
321 
322 	idr_preload(GFP_NOFS);
323 	spin_lock_irq(&c->lock);
324 	if (type == P9_TVERSION)
325 		tag = idr_alloc(&c->reqs, req, P9_NOTAG, P9_NOTAG + 1,
326 				GFP_NOWAIT);
327 	else
328 		tag = idr_alloc(&c->reqs, req, 0, P9_NOTAG, GFP_NOWAIT);
329 	req->tc.tag = tag;
330 	spin_unlock_irq(&c->lock);
331 	idr_preload_end();
332 	if (tag < 0)
333 		goto free;
334 
335 	/* Init ref to two because in the general case there is one ref
336 	 * that is put asynchronously by a writer thread, one ref
337 	 * temporarily given by p9_tag_lookup and put by p9_client_cb
338 	 * in the recv thread, and one ref put by p9_req_put in the
339 	 * main thread. The only exception is virtio that does not use
340 	 * p9_tag_lookup but does not have a writer thread either
341 	 * (the write happens synchronously in the request/zc_request
342 	 * callback), so p9_client_cb eats the second ref there
343 	 * as the pointer is duplicated directly by virtqueue_add_sgs()
344 	 */
345 	refcount_set(&req->refcount, 2);
346 
347 	return req;
348 
349 free:
350 	p9_fcall_fini(&req->tc);
351 	p9_fcall_fini(&req->rc);
352 free_req:
353 	kmem_cache_free(p9_req_cache, req);
354 	return ERR_PTR(-ENOMEM);
355 }
356 
357 /**
358  * p9_tag_lookup - Look up a request by tag.
359  * @c: Client session.
360  * @tag: Transaction ID.
361  *
362  * Context: Any context.
363  * Return: A request, or %NULL if there is no request with that tag.
364  */
365 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
366 {
367 	struct p9_req_t *req;
368 
369 	rcu_read_lock();
370 again:
371 	req = idr_find(&c->reqs, tag);
372 	if (req) {
373 		/* We have to be careful with the req found under rcu_read_lock
374 		 * Thanks to SLAB_TYPESAFE_BY_RCU we can safely try to get the
375 		 * ref again without corrupting other data, then check again
376 		 * that the tag matches once we have the ref
377 		 */
378 		if (!p9_req_try_get(req))
379 			goto again;
380 		if (req->tc.tag != tag) {
381 			p9_req_put(c, req);
382 			goto again;
383 		}
384 	}
385 	rcu_read_unlock();
386 
387 	return req;
388 }
389 EXPORT_SYMBOL(p9_tag_lookup);
390 
391 /**
392  * p9_tag_remove - Remove a tag.
393  * @c: Client session.
394  * @r: Request of reference.
395  *
396  * Context: Any context.
397  */
398 static void p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
399 {
400 	unsigned long flags;
401 	u16 tag = r->tc.tag;
402 
403 	p9_debug(P9_DEBUG_MUX, "freeing clnt %p req %p tag: %d\n", c, r, tag);
404 	spin_lock_irqsave(&c->lock, flags);
405 	idr_remove(&c->reqs, tag);
406 	spin_unlock_irqrestore(&c->lock, flags);
407 }
408 
409 int p9_req_put(struct p9_client *c, struct p9_req_t *r)
410 {
411 	if (refcount_dec_and_test(&r->refcount)) {
412 		p9_tag_remove(c, r);
413 
414 		p9_fcall_fini(&r->tc);
415 		p9_fcall_fini(&r->rc);
416 		kmem_cache_free(p9_req_cache, r);
417 		return 1;
418 	}
419 	return 0;
420 }
421 EXPORT_SYMBOL(p9_req_put);
422 
423 /**
424  * p9_tag_cleanup - cleans up tags structure and reclaims resources
425  * @c:  v9fs client struct
426  *
427  * This frees resources associated with the tags structure
428  *
429  */
430 static void p9_tag_cleanup(struct p9_client *c)
431 {
432 	struct p9_req_t *req;
433 	int id;
434 
435 	rcu_read_lock();
436 	idr_for_each_entry(&c->reqs, req, id) {
437 		pr_info("Tag %d still in use\n", id);
438 		if (p9_req_put(c, req) == 0)
439 			pr_warn("Packet with tag %d has still references",
440 				req->tc.tag);
441 	}
442 	rcu_read_unlock();
443 }
444 
445 /**
446  * p9_client_cb - call back from transport to client
447  * @c: client state
448  * @req: request received
449  * @status: request status, one of REQ_STATUS_*
450  *
451  */
452 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
453 {
454 	p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc.tag);
455 
456 	/* This barrier is needed to make sure any change made to req before
457 	 * the status change is visible to another thread
458 	 */
459 	smp_wmb();
460 	WRITE_ONCE(req->status, status);
461 
462 	wake_up(&req->wq);
463 	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
464 	p9_req_put(c, req);
465 }
466 EXPORT_SYMBOL(p9_client_cb);
467 
468 /**
469  * p9_parse_header - parse header arguments out of a packet
470  * @pdu: packet to parse
471  * @size: size of packet
472  * @type: type of request
473  * @tag: tag of packet
474  * @rewind: set if we need to rewind offset afterwards
475  */
476 
477 int
478 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type,
479 		int16_t *tag, int rewind)
480 {
481 	s8 r_type;
482 	s16 r_tag;
483 	s32 r_size;
484 	int offset = pdu->offset;
485 	int err;
486 
487 	pdu->offset = 0;
488 
489 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
490 	if (err)
491 		goto rewind_and_exit;
492 
493 	if (type)
494 		*type = r_type;
495 	if (tag)
496 		*tag = r_tag;
497 	if (size)
498 		*size = r_size;
499 
500 	if (pdu->size != r_size || r_size < 7) {
501 		err = -EINVAL;
502 		goto rewind_and_exit;
503 	}
504 
505 	pdu->id = r_type;
506 	pdu->tag = r_tag;
507 
508 	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
509 		 pdu->size, pdu->id, pdu->tag);
510 
511 rewind_and_exit:
512 	if (rewind)
513 		pdu->offset = offset;
514 	return err;
515 }
516 EXPORT_SYMBOL(p9_parse_header);
517 
518 /**
519  * p9_check_errors - check 9p packet for error return and process it
520  * @c: current client instance
521  * @req: request to parse and check for error conditions
522  *
523  * returns error code if one is discovered, otherwise returns 0
524  *
525  * this will have to be more complicated if we have multiple
526  * error packet types
527  */
528 
529 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
530 {
531 	s8 type;
532 	int err;
533 	int ecode;
534 
535 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
536 	if (req->rc.size > req->rc.capacity && !req->rc.zc) {
537 		pr_err("requested packet size too big: %d does not fit %zu (type=%d)\n",
538 		       req->rc.size, req->rc.capacity, req->rc.id);
539 		return -EIO;
540 	}
541 	/* dump the response from server
542 	 * This should be after check errors which poplulate pdu_fcall.
543 	 */
544 	trace_9p_protocol_dump(c, &req->rc);
545 	if (err) {
546 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
547 		return err;
548 	}
549 	if (type != P9_RERROR && type != P9_RLERROR)
550 		return 0;
551 
552 	if (!p9_is_proto_dotl(c)) {
553 		char *ename = NULL;
554 
555 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
556 				  &ename, &ecode);
557 		if (err) {
558 			kfree(ename);
559 			goto out_err;
560 		}
561 
562 		if (p9_is_proto_dotu(c) && ecode < 512)
563 			err = -ecode;
564 
565 		if (!err) {
566 			err = p9_errstr2errno(ename, strlen(ename));
567 
568 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
569 				 -ecode, ename);
570 		}
571 		kfree(ename);
572 	} else {
573 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
574 		if (err)
575 			goto out_err;
576 		err = -ecode;
577 
578 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
579 	}
580 
581 	return err;
582 
583 out_err:
584 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
585 
586 	return err;
587 }
588 
589 static struct p9_req_t *
590 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
591 
592 /**
593  * p9_client_flush - flush (cancel) a request
594  * @c: client state
595  * @oldreq: request to cancel
596  *
597  * This sents a flush for a particular request and links
598  * the flush request to the original request.  The current
599  * code only supports a single flush request although the protocol
600  * allows for multiple flush requests to be sent for a single request.
601  *
602  */
603 
604 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
605 {
606 	struct p9_req_t *req;
607 	s16 oldtag;
608 	int err;
609 
610 	err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
611 	if (err)
612 		return err;
613 
614 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
615 
616 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
617 	if (IS_ERR(req))
618 		return PTR_ERR(req);
619 
620 	/* if we haven't received a response for oldreq,
621 	 * remove it from the list
622 	 */
623 	if (READ_ONCE(oldreq->status) == REQ_STATUS_SENT) {
624 		if (c->trans_mod->cancelled)
625 			c->trans_mod->cancelled(c, oldreq);
626 	}
627 
628 	p9_req_put(c, req);
629 	return 0;
630 }
631 
632 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
633 					      int8_t type, uint t_size, uint r_size,
634 					      const char *fmt, va_list ap)
635 {
636 	int err;
637 	struct p9_req_t *req;
638 	va_list apc;
639 
640 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
641 
642 	/* we allow for any status other than disconnected */
643 	if (c->status == Disconnected)
644 		return ERR_PTR(-EIO);
645 
646 	/* if status is begin_disconnected we allow only clunk request */
647 	if (c->status == BeginDisconnect && type != P9_TCLUNK)
648 		return ERR_PTR(-EIO);
649 
650 	va_copy(apc, ap);
651 	req = p9_tag_alloc(c, type, t_size, r_size, fmt, apc);
652 	va_end(apc);
653 	if (IS_ERR(req))
654 		return req;
655 
656 	/* marshall the data */
657 	p9pdu_prepare(&req->tc, req->tc.tag, type);
658 	err = p9pdu_vwritef(&req->tc, c->proto_version, fmt, ap);
659 	if (err)
660 		goto reterr;
661 	p9pdu_finalize(c, &req->tc);
662 	trace_9p_client_req(c, type, req->tc.tag);
663 	return req;
664 reterr:
665 	p9_req_put(c, req);
666 	/* We have to put also the 2nd reference as it won't be used */
667 	p9_req_put(c, req);
668 	return ERR_PTR(err);
669 }
670 
671 /**
672  * p9_client_rpc - issue a request and wait for a response
673  * @c: client session
674  * @type: type of request
675  * @fmt: protocol format string (see protocol.c)
676  *
677  * Returns request structure (which client must free using p9_req_put)
678  */
679 
680 static struct p9_req_t *
681 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
682 {
683 	va_list ap;
684 	int sigpending, err;
685 	unsigned long flags;
686 	struct p9_req_t *req;
687 	/* Passing zero for tsize/rsize to p9_client_prepare_req() tells it to
688 	 * auto determine an appropriate (small) request/response size
689 	 * according to actual message data being sent. Currently RDMA
690 	 * transport is excluded from this response message size optimization,
691 	 * as it would not cope with it, due to its pooled response buffers
692 	 * (using an optimized request size for RDMA as well though).
693 	 */
694 	const uint tsize = 0;
695 	const uint rsize = c->trans_mod->pooled_rbuffers ? c->msize : 0;
696 
697 	va_start(ap, fmt);
698 	req = p9_client_prepare_req(c, type, tsize, rsize, fmt, ap);
699 	va_end(ap);
700 	if (IS_ERR(req))
701 		return req;
702 
703 	req->tc.zc = false;
704 	req->rc.zc = false;
705 
706 	if (signal_pending(current)) {
707 		sigpending = 1;
708 		clear_thread_flag(TIF_SIGPENDING);
709 	} else {
710 		sigpending = 0;
711 	}
712 
713 	err = c->trans_mod->request(c, req);
714 	if (err < 0) {
715 		/* write won't happen */
716 		p9_req_put(c, req);
717 		if (err != -ERESTARTSYS && err != -EFAULT)
718 			c->status = Disconnected;
719 		goto recalc_sigpending;
720 	}
721 again:
722 	/* Wait for the response */
723 	err = wait_event_killable(req->wq,
724 				  READ_ONCE(req->status) >= REQ_STATUS_RCVD);
725 
726 	/* Make sure our req is coherent with regard to updates in other
727 	 * threads - echoes to wmb() in the callback
728 	 */
729 	smp_rmb();
730 
731 	if (err == -ERESTARTSYS && c->status == Connected &&
732 	    type == P9_TFLUSH) {
733 		sigpending = 1;
734 		clear_thread_flag(TIF_SIGPENDING);
735 		goto again;
736 	}
737 
738 	if (READ_ONCE(req->status) == REQ_STATUS_ERROR) {
739 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
740 		err = req->t_err;
741 	}
742 	if (err == -ERESTARTSYS && c->status == Connected) {
743 		p9_debug(P9_DEBUG_MUX, "flushing\n");
744 		sigpending = 1;
745 		clear_thread_flag(TIF_SIGPENDING);
746 
747 		if (c->trans_mod->cancel(c, req))
748 			p9_client_flush(c, req);
749 
750 		/* if we received the response anyway, don't signal error */
751 		if (READ_ONCE(req->status) == REQ_STATUS_RCVD)
752 			err = 0;
753 	}
754 recalc_sigpending:
755 	if (sigpending) {
756 		spin_lock_irqsave(&current->sighand->siglock, flags);
757 		recalc_sigpending();
758 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
759 	}
760 	if (err < 0)
761 		goto reterr;
762 
763 	err = p9_check_errors(c, req);
764 	trace_9p_client_res(c, type, req->rc.tag, err);
765 	if (!err)
766 		return req;
767 reterr:
768 	p9_req_put(c, req);
769 	return ERR_PTR(safe_errno(err));
770 }
771 
772 /**
773  * p9_client_zc_rpc - issue a request and wait for a response
774  * @c: client session
775  * @type: type of request
776  * @uidata: destination for zero copy read
777  * @uodata: source for zero copy write
778  * @inlen: read buffer size
779  * @olen: write buffer size
780  * @in_hdrlen: reader header size, This is the size of response protocol data
781  * @fmt: protocol format string (see protocol.c)
782  *
783  * Returns request structure (which client must free using p9_req_put)
784  */
785 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
786 					 struct iov_iter *uidata,
787 					 struct iov_iter *uodata,
788 					 int inlen, int olen, int in_hdrlen,
789 					 const char *fmt, ...)
790 {
791 	va_list ap;
792 	int sigpending, err;
793 	unsigned long flags;
794 	struct p9_req_t *req;
795 
796 	va_start(ap, fmt);
797 	/* We allocate a inline protocol data of only 4k bytes.
798 	 * The actual content is passed in zero-copy fashion.
799 	 */
800 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, P9_ZC_HDR_SZ, fmt, ap);
801 	va_end(ap);
802 	if (IS_ERR(req))
803 		return req;
804 
805 	req->tc.zc = true;
806 	req->rc.zc = true;
807 
808 	if (signal_pending(current)) {
809 		sigpending = 1;
810 		clear_thread_flag(TIF_SIGPENDING);
811 	} else {
812 		sigpending = 0;
813 	}
814 
815 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
816 				       inlen, olen, in_hdrlen);
817 	if (err < 0) {
818 		if (err == -EIO)
819 			c->status = Disconnected;
820 		if (err != -ERESTARTSYS)
821 			goto recalc_sigpending;
822 	}
823 	if (READ_ONCE(req->status) == REQ_STATUS_ERROR) {
824 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
825 		err = req->t_err;
826 	}
827 	if (err == -ERESTARTSYS && c->status == Connected) {
828 		p9_debug(P9_DEBUG_MUX, "flushing\n");
829 		sigpending = 1;
830 		clear_thread_flag(TIF_SIGPENDING);
831 
832 		if (c->trans_mod->cancel(c, req))
833 			p9_client_flush(c, req);
834 
835 		/* if we received the response anyway, don't signal error */
836 		if (READ_ONCE(req->status) == REQ_STATUS_RCVD)
837 			err = 0;
838 	}
839 recalc_sigpending:
840 	if (sigpending) {
841 		spin_lock_irqsave(&current->sighand->siglock, flags);
842 		recalc_sigpending();
843 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
844 	}
845 	if (err < 0)
846 		goto reterr;
847 
848 	err = p9_check_errors(c, req);
849 	trace_9p_client_res(c, type, req->rc.tag, err);
850 	if (!err)
851 		return req;
852 reterr:
853 	p9_req_put(c, req);
854 	return ERR_PTR(safe_errno(err));
855 }
856 
857 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
858 {
859 	int ret;
860 	struct p9_fid *fid;
861 
862 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
863 	fid = kzalloc(sizeof(*fid), GFP_KERNEL);
864 	if (!fid)
865 		return NULL;
866 
867 	fid->mode = -1;
868 	fid->uid = current_fsuid();
869 	fid->clnt = clnt;
870 	refcount_set(&fid->count, 1);
871 
872 	idr_preload(GFP_KERNEL);
873 	spin_lock_irq(&clnt->lock);
874 	ret = idr_alloc_u32(&clnt->fids, fid, &fid->fid, P9_NOFID - 1,
875 			    GFP_NOWAIT);
876 	spin_unlock_irq(&clnt->lock);
877 	idr_preload_end();
878 	if (!ret) {
879 		trace_9p_fid_ref(fid, P9_FID_REF_CREATE);
880 		return fid;
881 	}
882 
883 	kfree(fid);
884 	return NULL;
885 }
886 
887 static void p9_fid_destroy(struct p9_fid *fid)
888 {
889 	struct p9_client *clnt;
890 	unsigned long flags;
891 
892 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
893 	trace_9p_fid_ref(fid, P9_FID_REF_DESTROY);
894 	clnt = fid->clnt;
895 	spin_lock_irqsave(&clnt->lock, flags);
896 	idr_remove(&clnt->fids, fid->fid);
897 	spin_unlock_irqrestore(&clnt->lock, flags);
898 	kfree(fid->rdir);
899 	kfree(fid);
900 }
901 
902 /* We also need to export tracepoint symbols for tracepoint_enabled() */
903 EXPORT_TRACEPOINT_SYMBOL(9p_fid_ref);
904 
905 void do_trace_9p_fid_get(struct p9_fid *fid)
906 {
907 	trace_9p_fid_ref(fid, P9_FID_REF_GET);
908 }
909 EXPORT_SYMBOL(do_trace_9p_fid_get);
910 
911 void do_trace_9p_fid_put(struct p9_fid *fid)
912 {
913 	trace_9p_fid_ref(fid, P9_FID_REF_PUT);
914 }
915 EXPORT_SYMBOL(do_trace_9p_fid_put);
916 
917 static int p9_client_version(struct p9_client *c)
918 {
919 	int err;
920 	struct p9_req_t *req;
921 	char *version = NULL;
922 	int msize;
923 
924 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
925 		 c->msize, c->proto_version);
926 
927 	switch (c->proto_version) {
928 	case p9_proto_2000L:
929 		req = p9_client_rpc(c, P9_TVERSION, "ds",
930 				    c->msize, "9P2000.L");
931 		break;
932 	case p9_proto_2000u:
933 		req = p9_client_rpc(c, P9_TVERSION, "ds",
934 				    c->msize, "9P2000.u");
935 		break;
936 	case p9_proto_legacy:
937 		req = p9_client_rpc(c, P9_TVERSION, "ds",
938 				    c->msize, "9P2000");
939 		break;
940 	default:
941 		return -EINVAL;
942 	}
943 
944 	if (IS_ERR(req))
945 		return PTR_ERR(req);
946 
947 	err = p9pdu_readf(&req->rc, c->proto_version, "ds", &msize, &version);
948 	if (err) {
949 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
950 		trace_9p_protocol_dump(c, &req->rc);
951 		goto error;
952 	}
953 
954 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
955 	if (!strncmp(version, "9P2000.L", 8)) {
956 		c->proto_version = p9_proto_2000L;
957 	} else if (!strncmp(version, "9P2000.u", 8)) {
958 		c->proto_version = p9_proto_2000u;
959 	} else if (!strncmp(version, "9P2000", 6)) {
960 		c->proto_version = p9_proto_legacy;
961 	} else {
962 		p9_debug(P9_DEBUG_ERROR,
963 			 "server returned an unknown version: %s\n", version);
964 		err = -EREMOTEIO;
965 		goto error;
966 	}
967 
968 	if (msize < 4096) {
969 		p9_debug(P9_DEBUG_ERROR,
970 			 "server returned a msize < 4096: %d\n", msize);
971 		err = -EREMOTEIO;
972 		goto error;
973 	}
974 	if (msize < c->msize)
975 		c->msize = msize;
976 
977 error:
978 	kfree(version);
979 	p9_req_put(c, req);
980 
981 	return err;
982 }
983 
984 struct p9_client *p9_client_create(const char *dev_name, char *options)
985 {
986 	int err;
987 	static atomic_t seqno = ATOMIC_INIT(0);
988 	struct p9_client *clnt;
989 	char *client_id;
990 	char *cache_name;
991 
992 	clnt = kmalloc(sizeof(*clnt), GFP_KERNEL);
993 	if (!clnt)
994 		return ERR_PTR(-ENOMEM);
995 
996 	clnt->trans_mod = NULL;
997 	clnt->trans = NULL;
998 	clnt->fcall_cache = NULL;
999 
1000 	client_id = utsname()->nodename;
1001 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
1002 
1003 	spin_lock_init(&clnt->lock);
1004 	idr_init(&clnt->fids);
1005 	idr_init(&clnt->reqs);
1006 
1007 	err = parse_opts(options, clnt);
1008 	if (err < 0)
1009 		goto free_client;
1010 
1011 	if (!clnt->trans_mod)
1012 		clnt->trans_mod = v9fs_get_default_trans();
1013 
1014 	if (!clnt->trans_mod) {
1015 		err = -EPROTONOSUPPORT;
1016 		p9_debug(P9_DEBUG_ERROR,
1017 			 "No transport defined or default transport\n");
1018 		goto free_client;
1019 	}
1020 
1021 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
1022 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
1023 
1024 	err = clnt->trans_mod->create(clnt, dev_name, options);
1025 	if (err)
1026 		goto put_trans;
1027 
1028 	if (clnt->msize > clnt->trans_mod->maxsize) {
1029 		clnt->msize = clnt->trans_mod->maxsize;
1030 		pr_info("Limiting 'msize' to %d as this is the maximum "
1031 			"supported by transport %s\n",
1032 			clnt->msize, clnt->trans_mod->name
1033 		);
1034 	}
1035 
1036 	if (clnt->msize < 4096) {
1037 		p9_debug(P9_DEBUG_ERROR,
1038 			 "Please specify a msize of at least 4k\n");
1039 		err = -EINVAL;
1040 		goto close_trans;
1041 	}
1042 
1043 	err = p9_client_version(clnt);
1044 	if (err)
1045 		goto close_trans;
1046 
1047 	cache_name = kasprintf(GFP_KERNEL,
1048 		"9p-fcall-cache-%u", atomic_inc_return(&seqno));
1049 	if (!cache_name) {
1050 		err = -ENOMEM;
1051 		goto close_trans;
1052 	}
1053 
1054 	/* P9_HDRSZ + 4 is the smallest packet header we can have that is
1055 	 * followed by data accessed from userspace by read
1056 	 */
1057 	clnt->fcall_cache =
1058 		kmem_cache_create_usercopy(cache_name, clnt->msize,
1059 					   0, 0, P9_HDRSZ + 4,
1060 					   clnt->msize - (P9_HDRSZ + 4),
1061 					   NULL);
1062 
1063 	kfree(cache_name);
1064 	return clnt;
1065 
1066 close_trans:
1067 	clnt->trans_mod->close(clnt);
1068 put_trans:
1069 	v9fs_put_trans(clnt->trans_mod);
1070 free_client:
1071 	kfree(clnt);
1072 	return ERR_PTR(err);
1073 }
1074 EXPORT_SYMBOL(p9_client_create);
1075 
1076 void p9_client_destroy(struct p9_client *clnt)
1077 {
1078 	struct p9_fid *fid;
1079 	int id;
1080 
1081 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1082 
1083 	if (clnt->trans_mod)
1084 		clnt->trans_mod->close(clnt);
1085 
1086 	v9fs_put_trans(clnt->trans_mod);
1087 
1088 	idr_for_each_entry(&clnt->fids, fid, id) {
1089 		pr_info("Found fid %d not clunked\n", fid->fid);
1090 		p9_fid_destroy(fid);
1091 	}
1092 
1093 	p9_tag_cleanup(clnt);
1094 
1095 	kmem_cache_destroy(clnt->fcall_cache);
1096 	kfree(clnt);
1097 }
1098 EXPORT_SYMBOL(p9_client_destroy);
1099 
1100 void p9_client_disconnect(struct p9_client *clnt)
1101 {
1102 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1103 	clnt->status = Disconnected;
1104 }
1105 EXPORT_SYMBOL(p9_client_disconnect);
1106 
1107 void p9_client_begin_disconnect(struct p9_client *clnt)
1108 {
1109 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1110 	clnt->status = BeginDisconnect;
1111 }
1112 EXPORT_SYMBOL(p9_client_begin_disconnect);
1113 
1114 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1115 				const char *uname, kuid_t n_uname,
1116 				const char *aname)
1117 {
1118 	int err;
1119 	struct p9_req_t *req;
1120 	struct p9_fid *fid;
1121 	struct p9_qid qid;
1122 
1123 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1124 		 afid ? afid->fid : -1, uname, aname);
1125 	fid = p9_fid_create(clnt);
1126 	if (!fid) {
1127 		err = -ENOMEM;
1128 		goto error;
1129 	}
1130 	fid->uid = n_uname;
1131 
1132 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
1133 			    afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
1134 	if (IS_ERR(req)) {
1135 		err = PTR_ERR(req);
1136 		goto error;
1137 	}
1138 
1139 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", &qid);
1140 	if (err) {
1141 		trace_9p_protocol_dump(clnt, &req->rc);
1142 		p9_req_put(clnt, req);
1143 		goto error;
1144 	}
1145 
1146 	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
1147 		 qid.type, qid.path, qid.version);
1148 
1149 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1150 
1151 	p9_req_put(clnt, req);
1152 	return fid;
1153 
1154 error:
1155 	if (fid)
1156 		p9_fid_destroy(fid);
1157 	return ERR_PTR(err);
1158 }
1159 EXPORT_SYMBOL(p9_client_attach);
1160 
1161 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
1162 			      const unsigned char * const *wnames, int clone)
1163 {
1164 	int err;
1165 	struct p9_client *clnt;
1166 	struct p9_fid *fid;
1167 	struct p9_qid *wqids;
1168 	struct p9_req_t *req;
1169 	u16 nwqids, count;
1170 
1171 	wqids = NULL;
1172 	clnt = oldfid->clnt;
1173 	if (clone) {
1174 		fid = p9_fid_create(clnt);
1175 		if (!fid) {
1176 			err = -ENOMEM;
1177 			goto error;
1178 		}
1179 
1180 		fid->uid = oldfid->uid;
1181 	} else {
1182 		fid = oldfid;
1183 	}
1184 
1185 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1186 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1187 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1188 			    nwname, wnames);
1189 	if (IS_ERR(req)) {
1190 		err = PTR_ERR(req);
1191 		goto error;
1192 	}
1193 
1194 	err = p9pdu_readf(&req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1195 	if (err) {
1196 		trace_9p_protocol_dump(clnt, &req->rc);
1197 		p9_req_put(clnt, req);
1198 		goto clunk_fid;
1199 	}
1200 	p9_req_put(clnt, req);
1201 
1202 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1203 
1204 	if (nwqids != nwname) {
1205 		err = -ENOENT;
1206 		goto clunk_fid;
1207 	}
1208 
1209 	for (count = 0; count < nwqids; count++)
1210 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1211 			 count, wqids[count].type,
1212 			 wqids[count].path,
1213 			 wqids[count].version);
1214 
1215 	if (nwname)
1216 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1217 	else
1218 		memmove(&fid->qid, &oldfid->qid, sizeof(struct p9_qid));
1219 
1220 	kfree(wqids);
1221 	return fid;
1222 
1223 clunk_fid:
1224 	kfree(wqids);
1225 	p9_fid_put(fid);
1226 	fid = NULL;
1227 
1228 error:
1229 	if (fid && fid != oldfid)
1230 		p9_fid_destroy(fid);
1231 
1232 	return ERR_PTR(err);
1233 }
1234 EXPORT_SYMBOL(p9_client_walk);
1235 
1236 int p9_client_open(struct p9_fid *fid, int mode)
1237 {
1238 	int err;
1239 	struct p9_client *clnt;
1240 	struct p9_req_t *req;
1241 	struct p9_qid qid;
1242 	int iounit;
1243 
1244 	clnt = fid->clnt;
1245 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1246 		 p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1247 
1248 	if (fid->mode != -1)
1249 		return -EINVAL;
1250 
1251 	if (p9_is_proto_dotl(clnt))
1252 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode & P9L_MODE_MASK);
1253 	else
1254 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode & P9L_MODE_MASK);
1255 	if (IS_ERR(req)) {
1256 		err = PTR_ERR(req);
1257 		goto error;
1258 	}
1259 
1260 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1261 	if (err) {
1262 		trace_9p_protocol_dump(clnt, &req->rc);
1263 		goto free_and_error;
1264 	}
1265 
1266 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1267 		 p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1268 		 qid.path, qid.version, iounit);
1269 
1270 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1271 	fid->mode = mode;
1272 	fid->iounit = iounit;
1273 
1274 free_and_error:
1275 	p9_req_put(clnt, req);
1276 error:
1277 	return err;
1278 }
1279 EXPORT_SYMBOL(p9_client_open);
1280 
1281 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags,
1282 			  u32 mode, kgid_t gid, struct p9_qid *qid)
1283 {
1284 	int err;
1285 	struct p9_client *clnt;
1286 	struct p9_req_t *req;
1287 	int iounit;
1288 
1289 	p9_debug(P9_DEBUG_9P,
1290 		 ">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1291 		 ofid->fid, name, flags, mode,
1292 		 from_kgid(&init_user_ns, gid));
1293 	clnt = ofid->clnt;
1294 
1295 	if (ofid->mode != -1)
1296 		return -EINVAL;
1297 
1298 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1299 			    mode & P9L_MODE_MASK, gid);
1300 	if (IS_ERR(req)) {
1301 		err = PTR_ERR(req);
1302 		goto error;
1303 	}
1304 
1305 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", qid, &iounit);
1306 	if (err) {
1307 		trace_9p_protocol_dump(clnt, &req->rc);
1308 		goto free_and_error;
1309 	}
1310 
1311 	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1312 		 qid->type, qid->path, qid->version, iounit);
1313 
1314 	memmove(&ofid->qid, qid, sizeof(struct p9_qid));
1315 	ofid->mode = flags;
1316 	ofid->iounit = iounit;
1317 
1318 free_and_error:
1319 	p9_req_put(clnt, req);
1320 error:
1321 	return err;
1322 }
1323 EXPORT_SYMBOL(p9_client_create_dotl);
1324 
1325 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1326 		     char *extension)
1327 {
1328 	int err;
1329 	struct p9_client *clnt;
1330 	struct p9_req_t *req;
1331 	struct p9_qid qid;
1332 	int iounit;
1333 
1334 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1335 		 fid->fid, name, perm, mode);
1336 	clnt = fid->clnt;
1337 
1338 	if (fid->mode != -1)
1339 		return -EINVAL;
1340 
1341 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1342 			    mode & P9L_MODE_MASK, extension);
1343 	if (IS_ERR(req)) {
1344 		err = PTR_ERR(req);
1345 		goto error;
1346 	}
1347 
1348 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1349 	if (err) {
1350 		trace_9p_protocol_dump(clnt, &req->rc);
1351 		goto free_and_error;
1352 	}
1353 
1354 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1355 		 qid.type, qid.path, qid.version, iounit);
1356 
1357 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1358 	fid->mode = mode;
1359 	fid->iounit = iounit;
1360 
1361 free_and_error:
1362 	p9_req_put(clnt, req);
1363 error:
1364 	return err;
1365 }
1366 EXPORT_SYMBOL(p9_client_fcreate);
1367 
1368 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1369 		      const char *symtgt, kgid_t gid, struct p9_qid *qid)
1370 {
1371 	int err;
1372 	struct p9_client *clnt;
1373 	struct p9_req_t *req;
1374 
1375 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1376 		 dfid->fid, name, symtgt);
1377 	clnt = dfid->clnt;
1378 
1379 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1380 			    gid);
1381 	if (IS_ERR(req)) {
1382 		err = PTR_ERR(req);
1383 		goto error;
1384 	}
1385 
1386 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
1387 	if (err) {
1388 		trace_9p_protocol_dump(clnt, &req->rc);
1389 		goto free_and_error;
1390 	}
1391 
1392 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1393 		 qid->type, qid->path, qid->version);
1394 
1395 free_and_error:
1396 	p9_req_put(clnt, req);
1397 error:
1398 	return err;
1399 }
1400 EXPORT_SYMBOL(p9_client_symlink);
1401 
1402 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1403 {
1404 	struct p9_client *clnt;
1405 	struct p9_req_t *req;
1406 
1407 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1408 		 dfid->fid, oldfid->fid, newname);
1409 	clnt = dfid->clnt;
1410 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1411 			    newname);
1412 	if (IS_ERR(req))
1413 		return PTR_ERR(req);
1414 
1415 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1416 	p9_req_put(clnt, req);
1417 	return 0;
1418 }
1419 EXPORT_SYMBOL(p9_client_link);
1420 
1421 int p9_client_fsync(struct p9_fid *fid, int datasync)
1422 {
1423 	int err = 0;
1424 	struct p9_client *clnt;
1425 	struct p9_req_t *req;
1426 
1427 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1428 		 fid->fid, datasync);
1429 	clnt = fid->clnt;
1430 
1431 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1432 	if (IS_ERR(req)) {
1433 		err = PTR_ERR(req);
1434 		goto error;
1435 	}
1436 
1437 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1438 
1439 	p9_req_put(clnt, req);
1440 
1441 error:
1442 	return err;
1443 }
1444 EXPORT_SYMBOL(p9_client_fsync);
1445 
1446 int p9_client_clunk(struct p9_fid *fid)
1447 {
1448 	int err = 0;
1449 	struct p9_client *clnt;
1450 	struct p9_req_t *req;
1451 	int retries = 0;
1452 
1453 again:
1454 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n",
1455 		 fid->fid, retries);
1456 	clnt = fid->clnt;
1457 
1458 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1459 	if (IS_ERR(req)) {
1460 		err = PTR_ERR(req);
1461 		goto error;
1462 	}
1463 
1464 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1465 
1466 	p9_req_put(clnt, req);
1467 error:
1468 	/* Fid is not valid even after a failed clunk
1469 	 * If interrupted, retry once then give up and
1470 	 * leak fid until umount.
1471 	 */
1472 	if (err == -ERESTARTSYS) {
1473 		if (retries++ == 0)
1474 			goto again;
1475 	} else {
1476 		p9_fid_destroy(fid);
1477 	}
1478 	return err;
1479 }
1480 EXPORT_SYMBOL(p9_client_clunk);
1481 
1482 int p9_client_remove(struct p9_fid *fid)
1483 {
1484 	int err = 0;
1485 	struct p9_client *clnt;
1486 	struct p9_req_t *req;
1487 
1488 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1489 	clnt = fid->clnt;
1490 
1491 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1492 	if (IS_ERR(req)) {
1493 		err = PTR_ERR(req);
1494 		goto error;
1495 	}
1496 
1497 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1498 
1499 	p9_req_put(clnt, req);
1500 error:
1501 	if (err == -ERESTARTSYS)
1502 		p9_fid_put(fid);
1503 	else
1504 		p9_fid_destroy(fid);
1505 	return err;
1506 }
1507 EXPORT_SYMBOL(p9_client_remove);
1508 
1509 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1510 {
1511 	int err = 0;
1512 	struct p9_req_t *req;
1513 	struct p9_client *clnt;
1514 
1515 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1516 		 dfid->fid, name, flags);
1517 
1518 	clnt = dfid->clnt;
1519 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1520 	if (IS_ERR(req)) {
1521 		err = PTR_ERR(req);
1522 		goto error;
1523 	}
1524 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1525 
1526 	p9_req_put(clnt, req);
1527 error:
1528 	return err;
1529 }
1530 EXPORT_SYMBOL(p9_client_unlinkat);
1531 
1532 int
1533 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1534 {
1535 	int total = 0;
1536 	*err = 0;
1537 
1538 	while (iov_iter_count(to)) {
1539 		int count;
1540 
1541 		count = p9_client_read_once(fid, offset, to, err);
1542 		if (!count || *err)
1543 			break;
1544 		offset += count;
1545 		total += count;
1546 	}
1547 	return total;
1548 }
1549 EXPORT_SYMBOL(p9_client_read);
1550 
1551 int
1552 p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
1553 		    int *err)
1554 {
1555 	struct p9_client *clnt = fid->clnt;
1556 	struct p9_req_t *req;
1557 	int count = iov_iter_count(to);
1558 	u32 rsize, received;
1559 	bool non_zc = false;
1560 	char *dataptr;
1561 
1562 	*err = 0;
1563 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %zu\n",
1564 		 fid->fid, offset, iov_iter_count(to));
1565 
1566 	rsize = fid->iounit;
1567 	if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1568 		rsize = clnt->msize - P9_IOHDRSZ;
1569 
1570 	if (count < rsize)
1571 		rsize = count;
1572 
1573 	/* Don't bother zerocopy for small IO (< 1024) */
1574 	if (clnt->trans_mod->zc_request && rsize > 1024) {
1575 		/* response header len is 11
1576 		 * PDU Header(7) + IO Size (4)
1577 		 */
1578 		req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1579 				       0, 11, "dqd", fid->fid,
1580 				       offset, rsize);
1581 	} else {
1582 		non_zc = true;
1583 		req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1584 				    rsize);
1585 	}
1586 	if (IS_ERR(req)) {
1587 		*err = PTR_ERR(req);
1588 		if (!non_zc)
1589 			iov_iter_revert(to, count - iov_iter_count(to));
1590 		return 0;
1591 	}
1592 
1593 	*err = p9pdu_readf(&req->rc, clnt->proto_version,
1594 			   "D", &received, &dataptr);
1595 	if (*err) {
1596 		if (!non_zc)
1597 			iov_iter_revert(to, count - iov_iter_count(to));
1598 		trace_9p_protocol_dump(clnt, &req->rc);
1599 		p9_req_put(clnt, req);
1600 		return 0;
1601 	}
1602 	if (rsize < received) {
1603 		pr_err("bogus RREAD count (%u > %u)\n", received, rsize);
1604 		*err = -EIO;
1605 		p9_req_put(clnt, req);
1606 		return 0;
1607 	}
1608 
1609 	p9_debug(P9_DEBUG_9P, "<<< RREAD count %u\n", received);
1610 
1611 	if (non_zc) {
1612 		int n = copy_to_iter(dataptr, received, to);
1613 
1614 		if (n != received) {
1615 			*err = -EFAULT;
1616 			p9_req_put(clnt, req);
1617 			return n;
1618 		}
1619 	} else {
1620 		iov_iter_revert(to, count - received - iov_iter_count(to));
1621 	}
1622 	p9_req_put(clnt, req);
1623 	return received;
1624 }
1625 EXPORT_SYMBOL(p9_client_read_once);
1626 
1627 int
1628 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1629 {
1630 	struct p9_client *clnt = fid->clnt;
1631 	struct p9_req_t *req;
1632 	int total = 0;
1633 	*err = 0;
1634 
1635 	while (iov_iter_count(from)) {
1636 		size_t count = iov_iter_count(from);
1637 		u32 rsize = fid->iounit;
1638 		u32 written;
1639 
1640 		if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1641 			rsize = clnt->msize - P9_IOHDRSZ;
1642 
1643 		if (count < rsize)
1644 			rsize = count;
1645 
1646 		p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %u (/%zu)\n",
1647 			 fid->fid, offset, rsize, count);
1648 
1649 		/* Don't bother zerocopy for small IO (< 1024) */
1650 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1651 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1652 					       rsize, P9_ZC_HDR_SZ, "dqd",
1653 					       fid->fid, offset, rsize);
1654 		} else {
1655 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1656 					    offset, rsize, from);
1657 		}
1658 		if (IS_ERR(req)) {
1659 			iov_iter_revert(from, count - iov_iter_count(from));
1660 			*err = PTR_ERR(req);
1661 			break;
1662 		}
1663 
1664 		*err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &written);
1665 		if (*err) {
1666 			iov_iter_revert(from, count - iov_iter_count(from));
1667 			trace_9p_protocol_dump(clnt, &req->rc);
1668 			p9_req_put(clnt, req);
1669 			break;
1670 		}
1671 		if (rsize < written) {
1672 			pr_err("bogus RWRITE count (%u > %u)\n", written, rsize);
1673 			*err = -EIO;
1674 			iov_iter_revert(from, count - iov_iter_count(from));
1675 			p9_req_put(clnt, req);
1676 			break;
1677 		}
1678 
1679 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %u\n", written);
1680 
1681 		p9_req_put(clnt, req);
1682 		iov_iter_revert(from, count - written - iov_iter_count(from));
1683 		total += written;
1684 		offset += written;
1685 	}
1686 	return total;
1687 }
1688 EXPORT_SYMBOL(p9_client_write);
1689 
1690 void
1691 p9_client_write_subreq(struct netfs_io_subrequest *subreq)
1692 {
1693 	struct netfs_io_request *wreq = subreq->rreq;
1694 	struct p9_fid *fid = wreq->netfs_priv;
1695 	struct p9_client *clnt = fid->clnt;
1696 	struct p9_req_t *req;
1697 	unsigned long long start = subreq->start + subreq->transferred;
1698 	int written, len = subreq->len - subreq->transferred;
1699 	int err;
1700 
1701 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu len %d\n",
1702 		 fid->fid, start, len);
1703 
1704 	/* Don't bother zerocopy for small IO (< 1024) */
1705 	if (clnt->trans_mod->zc_request && len > 1024) {
1706 		req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, &subreq->io_iter,
1707 				       0, wreq->len, P9_ZC_HDR_SZ, "dqd",
1708 				       fid->fid, start, len);
1709 	} else {
1710 		req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1711 				    start, len, &subreq->io_iter);
1712 	}
1713 	if (IS_ERR(req)) {
1714 		netfs_write_subrequest_terminated(subreq, PTR_ERR(req));
1715 		return;
1716 	}
1717 
1718 	err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &written);
1719 	if (err) {
1720 		trace_9p_protocol_dump(clnt, &req->rc);
1721 		p9_req_put(clnt, req);
1722 		netfs_write_subrequest_terminated(subreq, err);
1723 		return;
1724 	}
1725 
1726 	if (written > len) {
1727 		pr_err("bogus RWRITE count (%d > %u)\n", written, len);
1728 		written = -EIO;
1729 	}
1730 
1731 	p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", len);
1732 
1733 	p9_req_put(clnt, req);
1734 	netfs_write_subrequest_terminated(subreq, written);
1735 }
1736 EXPORT_SYMBOL(p9_client_write_subreq);
1737 
1738 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1739 {
1740 	int err;
1741 	struct p9_client *clnt;
1742 	struct p9_wstat *ret;
1743 	struct p9_req_t *req;
1744 	u16 ignored;
1745 
1746 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1747 
1748 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1749 	if (!ret)
1750 		return ERR_PTR(-ENOMEM);
1751 
1752 	clnt = fid->clnt;
1753 
1754 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1755 	if (IS_ERR(req)) {
1756 		err = PTR_ERR(req);
1757 		goto error;
1758 	}
1759 
1760 	err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
1761 	if (err) {
1762 		trace_9p_protocol_dump(clnt, &req->rc);
1763 		p9_req_put(clnt, req);
1764 		goto error;
1765 	}
1766 
1767 	p9_debug(P9_DEBUG_9P,
1768 		 "<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1769 		 "<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1770 		 "<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1771 		 "<<<    uid=%d gid=%d n_muid=%d\n",
1772 		 ret->size, ret->type, ret->dev, ret->qid.type, ret->qid.path,
1773 		 ret->qid.version, ret->mode,
1774 		 ret->atime, ret->mtime, ret->length,
1775 		 ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1776 		 from_kuid(&init_user_ns, ret->n_uid),
1777 		 from_kgid(&init_user_ns, ret->n_gid),
1778 		 from_kuid(&init_user_ns, ret->n_muid));
1779 
1780 	p9_req_put(clnt, req);
1781 	return ret;
1782 
1783 error:
1784 	kfree(ret);
1785 	return ERR_PTR(err);
1786 }
1787 EXPORT_SYMBOL(p9_client_stat);
1788 
1789 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1790 					    u64 request_mask)
1791 {
1792 	int err;
1793 	struct p9_client *clnt;
1794 	struct p9_stat_dotl *ret;
1795 	struct p9_req_t *req;
1796 
1797 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1798 		 fid->fid, request_mask);
1799 
1800 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1801 	if (!ret)
1802 		return ERR_PTR(-ENOMEM);
1803 
1804 	clnt = fid->clnt;
1805 
1806 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1807 	if (IS_ERR(req)) {
1808 		err = PTR_ERR(req);
1809 		goto error;
1810 	}
1811 
1812 	err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
1813 	if (err) {
1814 		trace_9p_protocol_dump(clnt, &req->rc);
1815 		p9_req_put(clnt, req);
1816 		goto error;
1817 	}
1818 
1819 	p9_debug(P9_DEBUG_9P, "<<< RGETATTR st_result_mask=%lld\n"
1820 		 "<<< qid=%x.%llx.%x\n"
1821 		 "<<< st_mode=%8.8x st_nlink=%llu\n"
1822 		 "<<< st_uid=%d st_gid=%d\n"
1823 		 "<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1824 		 "<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1825 		 "<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1826 		 "<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1827 		 "<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1828 		 "<<< st_gen=%lld st_data_version=%lld\n",
1829 		 ret->st_result_mask,
1830 		 ret->qid.type, ret->qid.path, ret->qid.version,
1831 		 ret->st_mode, ret->st_nlink,
1832 		 from_kuid(&init_user_ns, ret->st_uid),
1833 		 from_kgid(&init_user_ns, ret->st_gid),
1834 		 ret->st_rdev, ret->st_size, ret->st_blksize, ret->st_blocks,
1835 		 ret->st_atime_sec, ret->st_atime_nsec,
1836 		 ret->st_mtime_sec, ret->st_mtime_nsec,
1837 		 ret->st_ctime_sec, ret->st_ctime_nsec,
1838 		 ret->st_btime_sec, ret->st_btime_nsec,
1839 		 ret->st_gen, ret->st_data_version);
1840 
1841 	p9_req_put(clnt, req);
1842 	return ret;
1843 
1844 error:
1845 	kfree(ret);
1846 	return ERR_PTR(err);
1847 }
1848 EXPORT_SYMBOL(p9_client_getattr_dotl);
1849 
1850 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1851 {
1852 	int ret;
1853 
1854 	/* NOTE: size shouldn't include its own length */
1855 	/* size[2] type[2] dev[4] qid[13] */
1856 	/* mode[4] atime[4] mtime[4] length[8]*/
1857 	/* name[s] uid[s] gid[s] muid[s] */
1858 	ret = 2 + 4 + 13 + 4 + 4 + 4 + 8 + 2 + 2 + 2 + 2;
1859 
1860 	if (wst->name)
1861 		ret += strlen(wst->name);
1862 	if (wst->uid)
1863 		ret += strlen(wst->uid);
1864 	if (wst->gid)
1865 		ret += strlen(wst->gid);
1866 	if (wst->muid)
1867 		ret += strlen(wst->muid);
1868 
1869 	if (proto_version == p9_proto_2000u ||
1870 	    proto_version == p9_proto_2000L) {
1871 		/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1872 		ret += 2 + 4 + 4 + 4;
1873 		if (wst->extension)
1874 			ret += strlen(wst->extension);
1875 	}
1876 
1877 	return ret;
1878 }
1879 
1880 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1881 {
1882 	int err = 0;
1883 	struct p9_req_t *req;
1884 	struct p9_client *clnt;
1885 
1886 	clnt = fid->clnt;
1887 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1888 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n",
1889 		 fid->fid);
1890 	p9_debug(P9_DEBUG_9P,
1891 		 "     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1892 		 "     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1893 		 "     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1894 		 "     uid=%d gid=%d n_muid=%d\n",
1895 		 wst->size, wst->type, wst->dev, wst->qid.type,
1896 		 wst->qid.path, wst->qid.version,
1897 		 wst->mode, wst->atime, wst->mtime, wst->length,
1898 		 wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1899 		 from_kuid(&init_user_ns, wst->n_uid),
1900 		 from_kgid(&init_user_ns, wst->n_gid),
1901 		 from_kuid(&init_user_ns, wst->n_muid));
1902 
1903 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS",
1904 			    fid->fid, wst->size + 2, wst);
1905 	if (IS_ERR(req)) {
1906 		err = PTR_ERR(req);
1907 		goto error;
1908 	}
1909 
1910 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1911 
1912 	p9_req_put(clnt, req);
1913 error:
1914 	return err;
1915 }
1916 EXPORT_SYMBOL(p9_client_wstat);
1917 
1918 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1919 {
1920 	int err = 0;
1921 	struct p9_req_t *req;
1922 	struct p9_client *clnt;
1923 
1924 	clnt = fid->clnt;
1925 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1926 	p9_debug(P9_DEBUG_9P, "    valid=%x mode=%x uid=%d gid=%d size=%lld\n",
1927 		 p9attr->valid, p9attr->mode,
1928 		 from_kuid(&init_user_ns, p9attr->uid),
1929 		 from_kgid(&init_user_ns, p9attr->gid),
1930 		 p9attr->size);
1931 	p9_debug(P9_DEBUG_9P, "    atime_sec=%lld atime_nsec=%lld\n",
1932 		 p9attr->atime_sec, p9attr->atime_nsec);
1933 	p9_debug(P9_DEBUG_9P, "    mtime_sec=%lld mtime_nsec=%lld\n",
1934 		 p9attr->mtime_sec, p9attr->mtime_nsec);
1935 
1936 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1937 
1938 	if (IS_ERR(req)) {
1939 		err = PTR_ERR(req);
1940 		goto error;
1941 	}
1942 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1943 	p9_req_put(clnt, req);
1944 error:
1945 	return err;
1946 }
1947 EXPORT_SYMBOL(p9_client_setattr);
1948 
1949 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1950 {
1951 	int err;
1952 	struct p9_req_t *req;
1953 	struct p9_client *clnt;
1954 
1955 	clnt = fid->clnt;
1956 
1957 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1958 
1959 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1960 	if (IS_ERR(req)) {
1961 		err = PTR_ERR(req);
1962 		goto error;
1963 	}
1964 
1965 	err = p9pdu_readf(&req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1966 			  &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1967 			  &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1968 	if (err) {
1969 		trace_9p_protocol_dump(clnt, &req->rc);
1970 		p9_req_put(clnt, req);
1971 		goto error;
1972 	}
1973 
1974 	p9_debug(P9_DEBUG_9P,
1975 		 "<<< RSTATFS fid %d type 0x%x bsize %u blocks %llu bfree %llu bavail %llu files %llu ffree %llu fsid %llu namelen %u\n",
1976 		 fid->fid, sb->type, sb->bsize, sb->blocks, sb->bfree,
1977 		 sb->bavail, sb->files, sb->ffree, sb->fsid, sb->namelen);
1978 
1979 	p9_req_put(clnt, req);
1980 error:
1981 	return err;
1982 }
1983 EXPORT_SYMBOL(p9_client_statfs);
1984 
1985 int p9_client_rename(struct p9_fid *fid,
1986 		     struct p9_fid *newdirfid, const char *name)
1987 {
1988 	int err = 0;
1989 	struct p9_req_t *req;
1990 	struct p9_client *clnt;
1991 
1992 	clnt = fid->clnt;
1993 
1994 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1995 		 fid->fid, newdirfid->fid, name);
1996 
1997 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1998 			    newdirfid->fid, name);
1999 	if (IS_ERR(req)) {
2000 		err = PTR_ERR(req);
2001 		goto error;
2002 	}
2003 
2004 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
2005 
2006 	p9_req_put(clnt, req);
2007 error:
2008 	return err;
2009 }
2010 EXPORT_SYMBOL(p9_client_rename);
2011 
2012 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
2013 		       struct p9_fid *newdirfid, const char *new_name)
2014 {
2015 	int err = 0;
2016 	struct p9_req_t *req;
2017 	struct p9_client *clnt;
2018 
2019 	clnt = olddirfid->clnt;
2020 
2021 	p9_debug(P9_DEBUG_9P,
2022 		 ">>> TRENAMEAT olddirfid %d old name %s newdirfid %d new name %s\n",
2023 		 olddirfid->fid, old_name, newdirfid->fid, new_name);
2024 
2025 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
2026 			    old_name, newdirfid->fid, new_name);
2027 	if (IS_ERR(req)) {
2028 		err = PTR_ERR(req);
2029 		goto error;
2030 	}
2031 
2032 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
2033 		 newdirfid->fid, new_name);
2034 
2035 	p9_req_put(clnt, req);
2036 error:
2037 	return err;
2038 }
2039 EXPORT_SYMBOL(p9_client_renameat);
2040 
2041 /* An xattrwalk without @attr_name gives the fid for the lisxattr namespace
2042  */
2043 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
2044 				   const char *attr_name, u64 *attr_size)
2045 {
2046 	int err;
2047 	struct p9_req_t *req;
2048 	struct p9_client *clnt;
2049 	struct p9_fid *attr_fid;
2050 
2051 	clnt = file_fid->clnt;
2052 	attr_fid = p9_fid_create(clnt);
2053 	if (!attr_fid) {
2054 		err = -ENOMEM;
2055 		goto error;
2056 	}
2057 	p9_debug(P9_DEBUG_9P,
2058 		 ">>> TXATTRWALK file_fid %d, attr_fid %d name '%s'\n",
2059 		 file_fid->fid, attr_fid->fid, attr_name);
2060 
2061 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
2062 			    file_fid->fid, attr_fid->fid, attr_name);
2063 	if (IS_ERR(req)) {
2064 		err = PTR_ERR(req);
2065 		goto error;
2066 	}
2067 	err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
2068 	if (err) {
2069 		trace_9p_protocol_dump(clnt, &req->rc);
2070 		p9_req_put(clnt, req);
2071 		goto clunk_fid;
2072 	}
2073 	p9_req_put(clnt, req);
2074 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
2075 		 attr_fid->fid, *attr_size);
2076 	return attr_fid;
2077 clunk_fid:
2078 	p9_fid_put(attr_fid);
2079 	attr_fid = NULL;
2080 error:
2081 	if (attr_fid && attr_fid != file_fid)
2082 		p9_fid_destroy(attr_fid);
2083 
2084 	return ERR_PTR(err);
2085 }
2086 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
2087 
2088 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
2089 			  u64 attr_size, int flags)
2090 {
2091 	int err = 0;
2092 	struct p9_req_t *req;
2093 	struct p9_client *clnt;
2094 
2095 	p9_debug(P9_DEBUG_9P,
2096 		 ">>> TXATTRCREATE fid %d name  %s size %llu flag %d\n",
2097 		 fid->fid, name, attr_size, flags);
2098 	clnt = fid->clnt;
2099 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
2100 			    fid->fid, name, attr_size, flags);
2101 	if (IS_ERR(req)) {
2102 		err = PTR_ERR(req);
2103 		goto error;
2104 	}
2105 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
2106 	p9_req_put(clnt, req);
2107 error:
2108 	return err;
2109 }
2110 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
2111 
2112 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
2113 {
2114 	int err, non_zc = 0;
2115 	u32 rsize;
2116 	struct p9_client *clnt;
2117 	struct p9_req_t *req;
2118 	char *dataptr;
2119 	struct kvec kv = {.iov_base = data, .iov_len = count};
2120 	struct iov_iter to;
2121 
2122 	iov_iter_kvec(&to, ITER_DEST, &kv, 1, count);
2123 
2124 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %u\n",
2125 		 fid->fid, offset, count);
2126 
2127 	clnt = fid->clnt;
2128 
2129 	rsize = fid->iounit;
2130 	if (!rsize || rsize > clnt->msize - P9_READDIRHDRSZ)
2131 		rsize = clnt->msize - P9_READDIRHDRSZ;
2132 
2133 	if (count < rsize)
2134 		rsize = count;
2135 
2136 	/* Don't bother zerocopy for small IO (< 1024) */
2137 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2138 		/* response header len is 11
2139 		 * PDU Header(7) + IO Size (4)
2140 		 */
2141 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2142 				       11, "dqd", fid->fid, offset, rsize);
2143 	} else {
2144 		non_zc = 1;
2145 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2146 				    offset, rsize);
2147 	}
2148 	if (IS_ERR(req)) {
2149 		err = PTR_ERR(req);
2150 		goto error;
2151 	}
2152 
2153 	err = p9pdu_readf(&req->rc, clnt->proto_version, "D", &count, &dataptr);
2154 	if (err) {
2155 		trace_9p_protocol_dump(clnt, &req->rc);
2156 		goto free_and_error;
2157 	}
2158 	if (rsize < count) {
2159 		pr_err("bogus RREADDIR count (%u > %u)\n", count, rsize);
2160 		err = -EIO;
2161 		goto free_and_error;
2162 	}
2163 
2164 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %u\n", count);
2165 
2166 	if (non_zc)
2167 		memmove(data, dataptr, count);
2168 
2169 	p9_req_put(clnt, req);
2170 	return count;
2171 
2172 free_and_error:
2173 	p9_req_put(clnt, req);
2174 error:
2175 	return err;
2176 }
2177 EXPORT_SYMBOL(p9_client_readdir);
2178 
2179 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2180 			 dev_t rdev, kgid_t gid, struct p9_qid *qid)
2181 {
2182 	int err;
2183 	struct p9_client *clnt;
2184 	struct p9_req_t *req;
2185 
2186 	clnt = fid->clnt;
2187 	p9_debug(P9_DEBUG_9P,
2188 		 ">>> TMKNOD fid %d name %s mode %d major %d minor %d\n",
2189 		 fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2190 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2191 			    MAJOR(rdev), MINOR(rdev), gid);
2192 	if (IS_ERR(req))
2193 		return PTR_ERR(req);
2194 
2195 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2196 	if (err) {
2197 		trace_9p_protocol_dump(clnt, &req->rc);
2198 		goto error;
2199 	}
2200 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n",
2201 		 qid->type, qid->path, qid->version);
2202 
2203 error:
2204 	p9_req_put(clnt, req);
2205 	return err;
2206 }
2207 EXPORT_SYMBOL(p9_client_mknod_dotl);
2208 
2209 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2210 			 kgid_t gid, struct p9_qid *qid)
2211 {
2212 	int err;
2213 	struct p9_client *clnt;
2214 	struct p9_req_t *req;
2215 
2216 	clnt = fid->clnt;
2217 	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
2218 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
2219 	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg",
2220 			    fid->fid, name, mode, gid);
2221 	if (IS_ERR(req))
2222 		return PTR_ERR(req);
2223 
2224 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2225 	if (err) {
2226 		trace_9p_protocol_dump(clnt, &req->rc);
2227 		goto error;
2228 	}
2229 	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
2230 		 qid->path, qid->version);
2231 
2232 error:
2233 	p9_req_put(clnt, req);
2234 	return err;
2235 }
2236 EXPORT_SYMBOL(p9_client_mkdir_dotl);
2237 
2238 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
2239 {
2240 	int err;
2241 	struct p9_client *clnt;
2242 	struct p9_req_t *req;
2243 
2244 	clnt = fid->clnt;
2245 	p9_debug(P9_DEBUG_9P,
2246 		 ">>> TLOCK fid %d type %i flags %d start %lld length %lld proc_id %d client_id %s\n",
2247 		 fid->fid, flock->type, flock->flags, flock->start,
2248 		 flock->length, flock->proc_id, flock->client_id);
2249 
2250 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2251 			    flock->flags, flock->start, flock->length,
2252 			    flock->proc_id, flock->client_id);
2253 
2254 	if (IS_ERR(req))
2255 		return PTR_ERR(req);
2256 
2257 	err = p9pdu_readf(&req->rc, clnt->proto_version, "b", status);
2258 	if (err) {
2259 		trace_9p_protocol_dump(clnt, &req->rc);
2260 		goto error;
2261 	}
2262 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2263 error:
2264 	p9_req_put(clnt, req);
2265 	return err;
2266 }
2267 EXPORT_SYMBOL(p9_client_lock_dotl);
2268 
2269 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2270 {
2271 	int err;
2272 	struct p9_client *clnt;
2273 	struct p9_req_t *req;
2274 
2275 	clnt = fid->clnt;
2276 	p9_debug(P9_DEBUG_9P,
2277 		 ">>> TGETLOCK fid %d, type %i start %lld length %lld proc_id %d client_id %s\n",
2278 		 fid->fid, glock->type, glock->start, glock->length,
2279 		 glock->proc_id, glock->client_id);
2280 
2281 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,
2282 			    glock->type, glock->start, glock->length,
2283 			    glock->proc_id, glock->client_id);
2284 
2285 	if (IS_ERR(req))
2286 		return PTR_ERR(req);
2287 
2288 	err = p9pdu_readf(&req->rc, clnt->proto_version, "bqqds", &glock->type,
2289 			  &glock->start, &glock->length, &glock->proc_id,
2290 			  &glock->client_id);
2291 	if (err) {
2292 		trace_9p_protocol_dump(clnt, &req->rc);
2293 		goto error;
2294 	}
2295 	p9_debug(P9_DEBUG_9P,
2296 		 "<<< RGETLOCK type %i start %lld length %lld proc_id %d client_id %s\n",
2297 		 glock->type, glock->start, glock->length,
2298 		 glock->proc_id, glock->client_id);
2299 error:
2300 	p9_req_put(clnt, req);
2301 	return err;
2302 }
2303 EXPORT_SYMBOL(p9_client_getlock_dotl);
2304 
2305 int p9_client_readlink(struct p9_fid *fid, char **target)
2306 {
2307 	int err;
2308 	struct p9_client *clnt;
2309 	struct p9_req_t *req;
2310 
2311 	clnt = fid->clnt;
2312 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2313 
2314 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2315 	if (IS_ERR(req))
2316 		return PTR_ERR(req);
2317 
2318 	err = p9pdu_readf(&req->rc, clnt->proto_version, "s", target);
2319 	if (err) {
2320 		trace_9p_protocol_dump(clnt, &req->rc);
2321 		goto error;
2322 	}
2323 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2324 error:
2325 	p9_req_put(clnt, req);
2326 	return err;
2327 }
2328 EXPORT_SYMBOL(p9_client_readlink);
2329 
2330 int __init p9_client_init(void)
2331 {
2332 	p9_req_cache = KMEM_CACHE(p9_req_t, SLAB_TYPESAFE_BY_RCU);
2333 	return p9_req_cache ? 0 : -ENOMEM;
2334 }
2335 
2336 void __exit p9_client_exit(void)
2337 {
2338 	kmem_cache_destroy(p9_req_cache);
2339 }
2340