xref: /openbmc/linux/net/9p/client.c (revision 0646c28b)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * 9P Client
4  *
5  *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
6  *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
7  */
8 
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 
11 #include <linux/module.h>
12 #include <linux/errno.h>
13 #include <linux/fs.h>
14 #include <linux/poll.h>
15 #include <linux/idr.h>
16 #include <linux/mutex.h>
17 #include <linux/slab.h>
18 #include <linux/sched/signal.h>
19 #include <linux/uaccess.h>
20 #include <linux/uio.h>
21 #include <net/9p/9p.h>
22 #include <linux/parser.h>
23 #include <linux/seq_file.h>
24 #include <net/9p/client.h>
25 #include <net/9p/transport.h>
26 #include "protocol.h"
27 
28 #define CREATE_TRACE_POINTS
29 #include <trace/events/9p.h>
30 
31 #define DEFAULT_MSIZE (128 * 1024)
32 
33 /* Client Option Parsing (code inspired by NFS code)
34  *  - a little lazy - parse all client options
35  */
36 
37 enum {
38 	Opt_msize,
39 	Opt_trans,
40 	Opt_legacy,
41 	Opt_version,
42 	Opt_err,
43 };
44 
45 static const match_table_t tokens = {
46 	{Opt_msize, "msize=%u"},
47 	{Opt_legacy, "noextend"},
48 	{Opt_trans, "trans=%s"},
49 	{Opt_version, "version=%s"},
50 	{Opt_err, NULL},
51 };
52 
53 inline int p9_is_proto_dotl(struct p9_client *clnt)
54 {
55 	return clnt->proto_version == p9_proto_2000L;
56 }
57 EXPORT_SYMBOL(p9_is_proto_dotl);
58 
59 inline int p9_is_proto_dotu(struct p9_client *clnt)
60 {
61 	return clnt->proto_version == p9_proto_2000u;
62 }
63 EXPORT_SYMBOL(p9_is_proto_dotu);
64 
65 int p9_show_client_options(struct seq_file *m, struct p9_client *clnt)
66 {
67 	if (clnt->msize != DEFAULT_MSIZE)
68 		seq_printf(m, ",msize=%u", clnt->msize);
69 	seq_printf(m, ",trans=%s", clnt->trans_mod->name);
70 
71 	switch (clnt->proto_version) {
72 	case p9_proto_legacy:
73 		seq_puts(m, ",noextend");
74 		break;
75 	case p9_proto_2000u:
76 		seq_puts(m, ",version=9p2000.u");
77 		break;
78 	case p9_proto_2000L:
79 		/* Default */
80 		break;
81 	}
82 
83 	if (clnt->trans_mod->show_options)
84 		return clnt->trans_mod->show_options(m, clnt);
85 	return 0;
86 }
87 EXPORT_SYMBOL(p9_show_client_options);
88 
89 /* Some error codes are taken directly from the server replies,
90  * make sure they are valid.
91  */
92 static int safe_errno(int err)
93 {
94 	if (err > 0 || err < -MAX_ERRNO) {
95 		p9_debug(P9_DEBUG_ERROR, "Invalid error code %d\n", err);
96 		return -EPROTO;
97 	}
98 	return err;
99 }
100 
101 /* Interpret mount option for protocol version */
102 static int get_protocol_version(char *s)
103 {
104 	int version = -EINVAL;
105 
106 	if (!strcmp(s, "9p2000")) {
107 		version = p9_proto_legacy;
108 		p9_debug(P9_DEBUG_9P, "Protocol version: Legacy\n");
109 	} else if (!strcmp(s, "9p2000.u")) {
110 		version = p9_proto_2000u;
111 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.u\n");
112 	} else if (!strcmp(s, "9p2000.L")) {
113 		version = p9_proto_2000L;
114 		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.L\n");
115 	} else {
116 		pr_info("Unknown protocol version %s\n", s);
117 	}
118 
119 	return version;
120 }
121 
122 /**
123  * parse_opts - parse mount options into client structure
124  * @opts: options string passed from mount
125  * @clnt: existing v9fs client information
126  *
127  * Return 0 upon success, -ERRNO upon failure
128  */
129 
130 static int parse_opts(char *opts, struct p9_client *clnt)
131 {
132 	char *options, *tmp_options;
133 	char *p;
134 	substring_t args[MAX_OPT_ARGS];
135 	int option;
136 	char *s;
137 	int ret = 0;
138 
139 	clnt->proto_version = p9_proto_2000L;
140 	clnt->msize = DEFAULT_MSIZE;
141 
142 	if (!opts)
143 		return 0;
144 
145 	tmp_options = kstrdup(opts, GFP_KERNEL);
146 	if (!tmp_options)
147 		return -ENOMEM;
148 	options = tmp_options;
149 
150 	while ((p = strsep(&options, ",")) != NULL) {
151 		int token, r;
152 
153 		if (!*p)
154 			continue;
155 		token = match_token(p, tokens, args);
156 		switch (token) {
157 		case Opt_msize:
158 			r = match_int(&args[0], &option);
159 			if (r < 0) {
160 				p9_debug(P9_DEBUG_ERROR,
161 					 "integer field, but no integer?\n");
162 				ret = r;
163 				continue;
164 			}
165 			if (option < 4096) {
166 				p9_debug(P9_DEBUG_ERROR,
167 					 "msize should be at least 4k\n");
168 				ret = -EINVAL;
169 				continue;
170 			}
171 			clnt->msize = option;
172 			break;
173 		case Opt_trans:
174 			s = match_strdup(&args[0]);
175 			if (!s) {
176 				ret = -ENOMEM;
177 				p9_debug(P9_DEBUG_ERROR,
178 					 "problem allocating copy of trans arg\n");
179 				goto free_and_return;
180 			}
181 
182 			v9fs_put_trans(clnt->trans_mod);
183 			clnt->trans_mod = v9fs_get_trans_by_name(s);
184 			if (!clnt->trans_mod) {
185 				pr_info("Could not find request transport: %s\n",
186 					s);
187 				ret = -EINVAL;
188 			}
189 			kfree(s);
190 			break;
191 		case Opt_legacy:
192 			clnt->proto_version = p9_proto_legacy;
193 			break;
194 		case Opt_version:
195 			s = match_strdup(&args[0]);
196 			if (!s) {
197 				ret = -ENOMEM;
198 				p9_debug(P9_DEBUG_ERROR,
199 					 "problem allocating copy of version arg\n");
200 				goto free_and_return;
201 			}
202 			r = get_protocol_version(s);
203 			if (r < 0)
204 				ret = r;
205 			else
206 				clnt->proto_version = r;
207 			kfree(s);
208 			break;
209 		default:
210 			continue;
211 		}
212 	}
213 
214 free_and_return:
215 	if (ret)
216 		v9fs_put_trans(clnt->trans_mod);
217 	kfree(tmp_options);
218 	return ret;
219 }
220 
221 static int p9_fcall_init(struct p9_client *c, struct p9_fcall *fc,
222 			 int alloc_msize)
223 {
224 	if (likely(c->fcall_cache) && alloc_msize == c->msize) {
225 		fc->sdata = kmem_cache_alloc(c->fcall_cache, GFP_NOFS);
226 		fc->cache = c->fcall_cache;
227 	} else {
228 		fc->sdata = kmalloc(alloc_msize, GFP_NOFS);
229 		fc->cache = NULL;
230 	}
231 	if (!fc->sdata)
232 		return -ENOMEM;
233 	fc->capacity = alloc_msize;
234 	return 0;
235 }
236 
237 void p9_fcall_fini(struct p9_fcall *fc)
238 {
239 	/* sdata can be NULL for interrupted requests in trans_rdma,
240 	 * and kmem_cache_free does not do NULL-check for us
241 	 */
242 	if (unlikely(!fc->sdata))
243 		return;
244 
245 	if (fc->cache)
246 		kmem_cache_free(fc->cache, fc->sdata);
247 	else
248 		kfree(fc->sdata);
249 }
250 EXPORT_SYMBOL(p9_fcall_fini);
251 
252 static struct kmem_cache *p9_req_cache;
253 
254 /**
255  * p9_tag_alloc - Allocate a new request.
256  * @c: Client session.
257  * @type: Transaction type.
258  * @t_size: Buffer size for holding this request
259  * (automatic calculation by format template if 0).
260  * @r_size: Buffer size for holding server's reply on this request
261  * (automatic calculation by format template if 0).
262  * @fmt: Format template for assembling 9p request message
263  * (see p9pdu_vwritef).
264  * @ap: Variable arguments to be fed to passed format template
265  * (see p9pdu_vwritef).
266  *
267  * Context: Process context.
268  * Return: Pointer to new request.
269  */
270 static struct p9_req_t *
271 p9_tag_alloc(struct p9_client *c, int8_t type, uint t_size, uint r_size,
272 	      const char *fmt, va_list ap)
273 {
274 	struct p9_req_t *req = kmem_cache_alloc(p9_req_cache, GFP_NOFS);
275 	int alloc_tsize;
276 	int alloc_rsize;
277 	int tag;
278 	va_list apc;
279 
280 	va_copy(apc, ap);
281 	alloc_tsize = min_t(size_t, c->msize,
282 			    t_size ?: p9_msg_buf_size(c, type, fmt, apc));
283 	va_end(apc);
284 
285 	alloc_rsize = min_t(size_t, c->msize,
286 			    r_size ?: p9_msg_buf_size(c, type + 1, fmt, ap));
287 
288 	if (!req)
289 		return ERR_PTR(-ENOMEM);
290 
291 	if (p9_fcall_init(c, &req->tc, alloc_tsize))
292 		goto free_req;
293 	if (p9_fcall_init(c, &req->rc, alloc_rsize))
294 		goto free;
295 
296 	p9pdu_reset(&req->tc);
297 	p9pdu_reset(&req->rc);
298 	req->t_err = 0;
299 	req->status = REQ_STATUS_ALLOC;
300 	init_waitqueue_head(&req->wq);
301 	INIT_LIST_HEAD(&req->req_list);
302 
303 	idr_preload(GFP_NOFS);
304 	spin_lock_irq(&c->lock);
305 	if (type == P9_TVERSION)
306 		tag = idr_alloc(&c->reqs, req, P9_NOTAG, P9_NOTAG + 1,
307 				GFP_NOWAIT);
308 	else
309 		tag = idr_alloc(&c->reqs, req, 0, P9_NOTAG, GFP_NOWAIT);
310 	req->tc.tag = tag;
311 	spin_unlock_irq(&c->lock);
312 	idr_preload_end();
313 	if (tag < 0)
314 		goto free;
315 
316 	/* Init ref to two because in the general case there is one ref
317 	 * that is put asynchronously by a writer thread, one ref
318 	 * temporarily given by p9_tag_lookup and put by p9_client_cb
319 	 * in the recv thread, and one ref put by p9_req_put in the
320 	 * main thread. The only exception is virtio that does not use
321 	 * p9_tag_lookup but does not have a writer thread either
322 	 * (the write happens synchronously in the request/zc_request
323 	 * callback), so p9_client_cb eats the second ref there
324 	 * as the pointer is duplicated directly by virtqueue_add_sgs()
325 	 */
326 	refcount_set(&req->refcount, 2);
327 
328 	return req;
329 
330 free:
331 	p9_fcall_fini(&req->tc);
332 	p9_fcall_fini(&req->rc);
333 free_req:
334 	kmem_cache_free(p9_req_cache, req);
335 	return ERR_PTR(-ENOMEM);
336 }
337 
338 /**
339  * p9_tag_lookup - Look up a request by tag.
340  * @c: Client session.
341  * @tag: Transaction ID.
342  *
343  * Context: Any context.
344  * Return: A request, or %NULL if there is no request with that tag.
345  */
346 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
347 {
348 	struct p9_req_t *req;
349 
350 	rcu_read_lock();
351 again:
352 	req = idr_find(&c->reqs, tag);
353 	if (req) {
354 		/* We have to be careful with the req found under rcu_read_lock
355 		 * Thanks to SLAB_TYPESAFE_BY_RCU we can safely try to get the
356 		 * ref again without corrupting other data, then check again
357 		 * that the tag matches once we have the ref
358 		 */
359 		if (!p9_req_try_get(req))
360 			goto again;
361 		if (req->tc.tag != tag) {
362 			p9_req_put(c, req);
363 			goto again;
364 		}
365 	}
366 	rcu_read_unlock();
367 
368 	return req;
369 }
370 EXPORT_SYMBOL(p9_tag_lookup);
371 
372 /**
373  * p9_tag_remove - Remove a tag.
374  * @c: Client session.
375  * @r: Request of reference.
376  *
377  * Context: Any context.
378  */
379 static void p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
380 {
381 	unsigned long flags;
382 	u16 tag = r->tc.tag;
383 
384 	p9_debug(P9_DEBUG_MUX, "freeing clnt %p req %p tag: %d\n", c, r, tag);
385 	spin_lock_irqsave(&c->lock, flags);
386 	idr_remove(&c->reqs, tag);
387 	spin_unlock_irqrestore(&c->lock, flags);
388 }
389 
390 int p9_req_put(struct p9_client *c, struct p9_req_t *r)
391 {
392 	if (refcount_dec_and_test(&r->refcount)) {
393 		p9_tag_remove(c, r);
394 
395 		p9_fcall_fini(&r->tc);
396 		p9_fcall_fini(&r->rc);
397 		kmem_cache_free(p9_req_cache, r);
398 		return 1;
399 	}
400 	return 0;
401 }
402 EXPORT_SYMBOL(p9_req_put);
403 
404 /**
405  * p9_tag_cleanup - cleans up tags structure and reclaims resources
406  * @c:  v9fs client struct
407  *
408  * This frees resources associated with the tags structure
409  *
410  */
411 static void p9_tag_cleanup(struct p9_client *c)
412 {
413 	struct p9_req_t *req;
414 	int id;
415 
416 	rcu_read_lock();
417 	idr_for_each_entry(&c->reqs, req, id) {
418 		pr_info("Tag %d still in use\n", id);
419 		if (p9_req_put(c, req) == 0)
420 			pr_warn("Packet with tag %d has still references",
421 				req->tc.tag);
422 	}
423 	rcu_read_unlock();
424 }
425 
426 /**
427  * p9_client_cb - call back from transport to client
428  * @c: client state
429  * @req: request received
430  * @status: request status, one of REQ_STATUS_*
431  *
432  */
433 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
434 {
435 	p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc.tag);
436 
437 	/* This barrier is needed to make sure any change made to req before
438 	 * the status change is visible to another thread
439 	 */
440 	smp_wmb();
441 	req->status = status;
442 
443 	wake_up(&req->wq);
444 	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
445 	p9_req_put(c, req);
446 }
447 EXPORT_SYMBOL(p9_client_cb);
448 
449 /**
450  * p9_parse_header - parse header arguments out of a packet
451  * @pdu: packet to parse
452  * @size: size of packet
453  * @type: type of request
454  * @tag: tag of packet
455  * @rewind: set if we need to rewind offset afterwards
456  */
457 
458 int
459 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type,
460 		int16_t *tag, int rewind)
461 {
462 	s8 r_type;
463 	s16 r_tag;
464 	s32 r_size;
465 	int offset = pdu->offset;
466 	int err;
467 
468 	pdu->offset = 0;
469 
470 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
471 	if (err)
472 		goto rewind_and_exit;
473 
474 	if (type)
475 		*type = r_type;
476 	if (tag)
477 		*tag = r_tag;
478 	if (size)
479 		*size = r_size;
480 
481 	if (pdu->size != r_size || r_size < 7) {
482 		err = -EINVAL;
483 		goto rewind_and_exit;
484 	}
485 
486 	pdu->id = r_type;
487 	pdu->tag = r_tag;
488 
489 	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
490 		 pdu->size, pdu->id, pdu->tag);
491 
492 rewind_and_exit:
493 	if (rewind)
494 		pdu->offset = offset;
495 	return err;
496 }
497 EXPORT_SYMBOL(p9_parse_header);
498 
499 /**
500  * p9_check_errors - check 9p packet for error return and process it
501  * @c: current client instance
502  * @req: request to parse and check for error conditions
503  *
504  * returns error code if one is discovered, otherwise returns 0
505  *
506  * this will have to be more complicated if we have multiple
507  * error packet types
508  */
509 
510 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
511 {
512 	s8 type;
513 	int err;
514 	int ecode;
515 
516 	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
517 	if (req->rc.size >= c->msize) {
518 		p9_debug(P9_DEBUG_ERROR,
519 			 "requested packet size too big: %d\n",
520 			 req->rc.size);
521 		return -EIO;
522 	}
523 	/* dump the response from server
524 	 * This should be after check errors which poplulate pdu_fcall.
525 	 */
526 	trace_9p_protocol_dump(c, &req->rc);
527 	if (err) {
528 		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
529 		return err;
530 	}
531 	if (type != P9_RERROR && type != P9_RLERROR)
532 		return 0;
533 
534 	if (!p9_is_proto_dotl(c)) {
535 		char *ename;
536 
537 		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
538 				  &ename, &ecode);
539 		if (err)
540 			goto out_err;
541 
542 		if (p9_is_proto_dotu(c) && ecode < 512)
543 			err = -ecode;
544 
545 		if (!err) {
546 			err = p9_errstr2errno(ename, strlen(ename));
547 
548 			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
549 				 -ecode, ename);
550 		}
551 		kfree(ename);
552 	} else {
553 		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
554 		if (err)
555 			goto out_err;
556 		err = -ecode;
557 
558 		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
559 	}
560 
561 	return err;
562 
563 out_err:
564 	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
565 
566 	return err;
567 }
568 
569 static struct p9_req_t *
570 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
571 
572 /**
573  * p9_client_flush - flush (cancel) a request
574  * @c: client state
575  * @oldreq: request to cancel
576  *
577  * This sents a flush for a particular request and links
578  * the flush request to the original request.  The current
579  * code only supports a single flush request although the protocol
580  * allows for multiple flush requests to be sent for a single request.
581  *
582  */
583 
584 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
585 {
586 	struct p9_req_t *req;
587 	s16 oldtag;
588 	int err;
589 
590 	err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
591 	if (err)
592 		return err;
593 
594 	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
595 
596 	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
597 	if (IS_ERR(req))
598 		return PTR_ERR(req);
599 
600 	/* if we haven't received a response for oldreq,
601 	 * remove it from the list
602 	 */
603 	if (oldreq->status == REQ_STATUS_SENT) {
604 		if (c->trans_mod->cancelled)
605 			c->trans_mod->cancelled(c, oldreq);
606 	}
607 
608 	p9_req_put(c, req);
609 	return 0;
610 }
611 
612 static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
613 					      int8_t type, uint t_size, uint r_size,
614 					      const char *fmt, va_list ap)
615 {
616 	int err;
617 	struct p9_req_t *req;
618 	va_list apc;
619 
620 	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
621 
622 	/* we allow for any status other than disconnected */
623 	if (c->status == Disconnected)
624 		return ERR_PTR(-EIO);
625 
626 	/* if status is begin_disconnected we allow only clunk request */
627 	if (c->status == BeginDisconnect && type != P9_TCLUNK)
628 		return ERR_PTR(-EIO);
629 
630 	va_copy(apc, ap);
631 	req = p9_tag_alloc(c, type, t_size, r_size, fmt, apc);
632 	va_end(apc);
633 	if (IS_ERR(req))
634 		return req;
635 
636 	/* marshall the data */
637 	p9pdu_prepare(&req->tc, req->tc.tag, type);
638 	err = p9pdu_vwritef(&req->tc, c->proto_version, fmt, ap);
639 	if (err)
640 		goto reterr;
641 	p9pdu_finalize(c, &req->tc);
642 	trace_9p_client_req(c, type, req->tc.tag);
643 	return req;
644 reterr:
645 	p9_req_put(c, req);
646 	/* We have to put also the 2nd reference as it won't be used */
647 	p9_req_put(c, req);
648 	return ERR_PTR(err);
649 }
650 
651 /**
652  * p9_client_rpc - issue a request and wait for a response
653  * @c: client session
654  * @type: type of request
655  * @fmt: protocol format string (see protocol.c)
656  *
657  * Returns request structure (which client must free using p9_req_put)
658  */
659 
660 static struct p9_req_t *
661 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
662 {
663 	va_list ap;
664 	int sigpending, err;
665 	unsigned long flags;
666 	struct p9_req_t *req;
667 	/* Passing zero for tsize/rsize to p9_client_prepare_req() tells it to
668 	 * auto determine an appropriate (small) request/response size
669 	 * according to actual message data being sent. Currently RDMA
670 	 * transport is excluded from this response message size optimization,
671 	 * as it would not cope with it, due to its pooled response buffers
672 	 * (using an optimized request size for RDMA as well though).
673 	 */
674 	const uint tsize = 0;
675 	const uint rsize = c->trans_mod->pooled_rbuffers ? c->msize : 0;
676 
677 	va_start(ap, fmt);
678 	req = p9_client_prepare_req(c, type, tsize, rsize, fmt, ap);
679 	va_end(ap);
680 	if (IS_ERR(req))
681 		return req;
682 
683 	if (signal_pending(current)) {
684 		sigpending = 1;
685 		clear_thread_flag(TIF_SIGPENDING);
686 	} else {
687 		sigpending = 0;
688 	}
689 
690 	err = c->trans_mod->request(c, req);
691 	if (err < 0) {
692 		/* write won't happen */
693 		p9_req_put(c, req);
694 		if (err != -ERESTARTSYS && err != -EFAULT)
695 			c->status = Disconnected;
696 		goto recalc_sigpending;
697 	}
698 again:
699 	/* Wait for the response */
700 	err = wait_event_killable(req->wq, req->status >= REQ_STATUS_RCVD);
701 
702 	/* Make sure our req is coherent with regard to updates in other
703 	 * threads - echoes to wmb() in the callback
704 	 */
705 	smp_rmb();
706 
707 	if (err == -ERESTARTSYS && c->status == Connected &&
708 	    type == P9_TFLUSH) {
709 		sigpending = 1;
710 		clear_thread_flag(TIF_SIGPENDING);
711 		goto again;
712 	}
713 
714 	if (req->status == REQ_STATUS_ERROR) {
715 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
716 		err = req->t_err;
717 	}
718 	if (err == -ERESTARTSYS && c->status == Connected) {
719 		p9_debug(P9_DEBUG_MUX, "flushing\n");
720 		sigpending = 1;
721 		clear_thread_flag(TIF_SIGPENDING);
722 
723 		if (c->trans_mod->cancel(c, req))
724 			p9_client_flush(c, req);
725 
726 		/* if we received the response anyway, don't signal error */
727 		if (req->status == REQ_STATUS_RCVD)
728 			err = 0;
729 	}
730 recalc_sigpending:
731 	if (sigpending) {
732 		spin_lock_irqsave(&current->sighand->siglock, flags);
733 		recalc_sigpending();
734 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
735 	}
736 	if (err < 0)
737 		goto reterr;
738 
739 	err = p9_check_errors(c, req);
740 	trace_9p_client_res(c, type, req->rc.tag, err);
741 	if (!err)
742 		return req;
743 reterr:
744 	p9_req_put(c, req);
745 	return ERR_PTR(safe_errno(err));
746 }
747 
748 /**
749  * p9_client_zc_rpc - issue a request and wait for a response
750  * @c: client session
751  * @type: type of request
752  * @uidata: destination for zero copy read
753  * @uodata: source for zero copy write
754  * @inlen: read buffer size
755  * @olen: write buffer size
756  * @in_hdrlen: reader header size, This is the size of response protocol data
757  * @fmt: protocol format string (see protocol.c)
758  *
759  * Returns request structure (which client must free using p9_req_put)
760  */
761 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
762 					 struct iov_iter *uidata,
763 					 struct iov_iter *uodata,
764 					 int inlen, int olen, int in_hdrlen,
765 					 const char *fmt, ...)
766 {
767 	va_list ap;
768 	int sigpending, err;
769 	unsigned long flags;
770 	struct p9_req_t *req;
771 
772 	va_start(ap, fmt);
773 	/* We allocate a inline protocol data of only 4k bytes.
774 	 * The actual content is passed in zero-copy fashion.
775 	 */
776 	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, P9_ZC_HDR_SZ, fmt, ap);
777 	va_end(ap);
778 	if (IS_ERR(req))
779 		return req;
780 
781 	if (signal_pending(current)) {
782 		sigpending = 1;
783 		clear_thread_flag(TIF_SIGPENDING);
784 	} else {
785 		sigpending = 0;
786 	}
787 
788 	err = c->trans_mod->zc_request(c, req, uidata, uodata,
789 				       inlen, olen, in_hdrlen);
790 	if (err < 0) {
791 		if (err == -EIO)
792 			c->status = Disconnected;
793 		if (err != -ERESTARTSYS)
794 			goto recalc_sigpending;
795 	}
796 	if (req->status == REQ_STATUS_ERROR) {
797 		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
798 		err = req->t_err;
799 	}
800 	if (err == -ERESTARTSYS && c->status == Connected) {
801 		p9_debug(P9_DEBUG_MUX, "flushing\n");
802 		sigpending = 1;
803 		clear_thread_flag(TIF_SIGPENDING);
804 
805 		if (c->trans_mod->cancel(c, req))
806 			p9_client_flush(c, req);
807 
808 		/* if we received the response anyway, don't signal error */
809 		if (req->status == REQ_STATUS_RCVD)
810 			err = 0;
811 	}
812 recalc_sigpending:
813 	if (sigpending) {
814 		spin_lock_irqsave(&current->sighand->siglock, flags);
815 		recalc_sigpending();
816 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
817 	}
818 	if (err < 0)
819 		goto reterr;
820 
821 	err = p9_check_errors(c, req);
822 	trace_9p_client_res(c, type, req->rc.tag, err);
823 	if (!err)
824 		return req;
825 reterr:
826 	p9_req_put(c, req);
827 	return ERR_PTR(safe_errno(err));
828 }
829 
830 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
831 {
832 	int ret;
833 	struct p9_fid *fid;
834 
835 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
836 	fid = kzalloc(sizeof(*fid), GFP_KERNEL);
837 	if (!fid)
838 		return NULL;
839 
840 	fid->mode = -1;
841 	fid->uid = current_fsuid();
842 	fid->clnt = clnt;
843 	refcount_set(&fid->count, 1);
844 
845 	idr_preload(GFP_KERNEL);
846 	spin_lock_irq(&clnt->lock);
847 	ret = idr_alloc_u32(&clnt->fids, fid, &fid->fid, P9_NOFID - 1,
848 			    GFP_NOWAIT);
849 	spin_unlock_irq(&clnt->lock);
850 	idr_preload_end();
851 	if (!ret) {
852 		trace_9p_fid_ref(fid, P9_FID_REF_CREATE);
853 		return fid;
854 	}
855 
856 	kfree(fid);
857 	return NULL;
858 }
859 
860 static void p9_fid_destroy(struct p9_fid *fid)
861 {
862 	struct p9_client *clnt;
863 	unsigned long flags;
864 
865 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
866 	trace_9p_fid_ref(fid, P9_FID_REF_DESTROY);
867 	clnt = fid->clnt;
868 	spin_lock_irqsave(&clnt->lock, flags);
869 	idr_remove(&clnt->fids, fid->fid);
870 	spin_unlock_irqrestore(&clnt->lock, flags);
871 	kfree(fid->rdir);
872 	kfree(fid);
873 }
874 
875 /* We also need to export tracepoint symbols for tracepoint_enabled() */
876 EXPORT_TRACEPOINT_SYMBOL(9p_fid_ref);
877 
878 void do_trace_9p_fid_get(struct p9_fid *fid)
879 {
880 	trace_9p_fid_ref(fid, P9_FID_REF_GET);
881 }
882 EXPORT_SYMBOL(do_trace_9p_fid_get);
883 
884 void do_trace_9p_fid_put(struct p9_fid *fid)
885 {
886 	trace_9p_fid_ref(fid, P9_FID_REF_PUT);
887 }
888 EXPORT_SYMBOL(do_trace_9p_fid_put);
889 
890 static int p9_client_version(struct p9_client *c)
891 {
892 	int err = 0;
893 	struct p9_req_t *req;
894 	char *version = NULL;
895 	int msize;
896 
897 	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
898 		 c->msize, c->proto_version);
899 
900 	switch (c->proto_version) {
901 	case p9_proto_2000L:
902 		req = p9_client_rpc(c, P9_TVERSION, "ds",
903 				    c->msize, "9P2000.L");
904 		break;
905 	case p9_proto_2000u:
906 		req = p9_client_rpc(c, P9_TVERSION, "ds",
907 				    c->msize, "9P2000.u");
908 		break;
909 	case p9_proto_legacy:
910 		req = p9_client_rpc(c, P9_TVERSION, "ds",
911 				    c->msize, "9P2000");
912 		break;
913 	default:
914 		return -EINVAL;
915 	}
916 
917 	if (IS_ERR(req))
918 		return PTR_ERR(req);
919 
920 	err = p9pdu_readf(&req->rc, c->proto_version, "ds", &msize, &version);
921 	if (err) {
922 		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
923 		trace_9p_protocol_dump(c, &req->rc);
924 		goto error;
925 	}
926 
927 	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
928 	if (!strncmp(version, "9P2000.L", 8)) {
929 		c->proto_version = p9_proto_2000L;
930 	} else if (!strncmp(version, "9P2000.u", 8)) {
931 		c->proto_version = p9_proto_2000u;
932 	} else if (!strncmp(version, "9P2000", 6)) {
933 		c->proto_version = p9_proto_legacy;
934 	} else {
935 		p9_debug(P9_DEBUG_ERROR,
936 			 "server returned an unknown version: %s\n", version);
937 		err = -EREMOTEIO;
938 		goto error;
939 	}
940 
941 	if (msize < 4096) {
942 		p9_debug(P9_DEBUG_ERROR,
943 			 "server returned a msize < 4096: %d\n", msize);
944 		err = -EREMOTEIO;
945 		goto error;
946 	}
947 	if (msize < c->msize)
948 		c->msize = msize;
949 
950 error:
951 	kfree(version);
952 	p9_req_put(c, req);
953 
954 	return err;
955 }
956 
957 struct p9_client *p9_client_create(const char *dev_name, char *options)
958 {
959 	int err;
960 	struct p9_client *clnt;
961 	char *client_id;
962 
963 	err = 0;
964 	clnt = kmalloc(sizeof(*clnt), GFP_KERNEL);
965 	if (!clnt)
966 		return ERR_PTR(-ENOMEM);
967 
968 	clnt->trans_mod = NULL;
969 	clnt->trans = NULL;
970 	clnt->fcall_cache = NULL;
971 
972 	client_id = utsname()->nodename;
973 	memcpy(clnt->name, client_id, strlen(client_id) + 1);
974 
975 	spin_lock_init(&clnt->lock);
976 	idr_init(&clnt->fids);
977 	idr_init(&clnt->reqs);
978 
979 	err = parse_opts(options, clnt);
980 	if (err < 0)
981 		goto free_client;
982 
983 	if (!clnt->trans_mod)
984 		clnt->trans_mod = v9fs_get_default_trans();
985 
986 	if (!clnt->trans_mod) {
987 		err = -EPROTONOSUPPORT;
988 		p9_debug(P9_DEBUG_ERROR,
989 			 "No transport defined or default transport\n");
990 		goto free_client;
991 	}
992 
993 	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
994 		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
995 
996 	err = clnt->trans_mod->create(clnt, dev_name, options);
997 	if (err)
998 		goto put_trans;
999 
1000 	if (clnt->msize > clnt->trans_mod->maxsize) {
1001 		clnt->msize = clnt->trans_mod->maxsize;
1002 		pr_info("Limiting 'msize' to %d as this is the maximum "
1003 			"supported by transport %s\n",
1004 			clnt->msize, clnt->trans_mod->name
1005 		);
1006 	}
1007 
1008 	if (clnt->msize < 4096) {
1009 		p9_debug(P9_DEBUG_ERROR,
1010 			 "Please specify a msize of at least 4k\n");
1011 		err = -EINVAL;
1012 		goto close_trans;
1013 	}
1014 
1015 	err = p9_client_version(clnt);
1016 	if (err)
1017 		goto close_trans;
1018 
1019 	/* P9_HDRSZ + 4 is the smallest packet header we can have that is
1020 	 * followed by data accessed from userspace by read
1021 	 */
1022 	clnt->fcall_cache =
1023 		kmem_cache_create_usercopy("9p-fcall-cache", clnt->msize,
1024 					   0, 0, P9_HDRSZ + 4,
1025 					   clnt->msize - (P9_HDRSZ + 4),
1026 					   NULL);
1027 
1028 	return clnt;
1029 
1030 close_trans:
1031 	clnt->trans_mod->close(clnt);
1032 put_trans:
1033 	v9fs_put_trans(clnt->trans_mod);
1034 free_client:
1035 	kfree(clnt);
1036 	return ERR_PTR(err);
1037 }
1038 EXPORT_SYMBOL(p9_client_create);
1039 
1040 void p9_client_destroy(struct p9_client *clnt)
1041 {
1042 	struct p9_fid *fid;
1043 	int id;
1044 
1045 	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
1046 
1047 	if (clnt->trans_mod)
1048 		clnt->trans_mod->close(clnt);
1049 
1050 	v9fs_put_trans(clnt->trans_mod);
1051 
1052 	idr_for_each_entry(&clnt->fids, fid, id) {
1053 		pr_info("Found fid %d not clunked\n", fid->fid);
1054 		p9_fid_destroy(fid);
1055 	}
1056 
1057 	p9_tag_cleanup(clnt);
1058 
1059 	kmem_cache_destroy(clnt->fcall_cache);
1060 	kfree(clnt);
1061 }
1062 EXPORT_SYMBOL(p9_client_destroy);
1063 
1064 void p9_client_disconnect(struct p9_client *clnt)
1065 {
1066 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1067 	clnt->status = Disconnected;
1068 }
1069 EXPORT_SYMBOL(p9_client_disconnect);
1070 
1071 void p9_client_begin_disconnect(struct p9_client *clnt)
1072 {
1073 	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
1074 	clnt->status = BeginDisconnect;
1075 }
1076 EXPORT_SYMBOL(p9_client_begin_disconnect);
1077 
1078 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
1079 				const char *uname, kuid_t n_uname,
1080 				const char *aname)
1081 {
1082 	int err = 0;
1083 	struct p9_req_t *req;
1084 	struct p9_fid *fid;
1085 	struct p9_qid qid;
1086 
1087 	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
1088 		 afid ? afid->fid : -1, uname, aname);
1089 	fid = p9_fid_create(clnt);
1090 	if (!fid) {
1091 		err = -ENOMEM;
1092 		goto error;
1093 	}
1094 	fid->uid = n_uname;
1095 
1096 	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
1097 			    afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
1098 	if (IS_ERR(req)) {
1099 		err = PTR_ERR(req);
1100 		goto error;
1101 	}
1102 
1103 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", &qid);
1104 	if (err) {
1105 		trace_9p_protocol_dump(clnt, &req->rc);
1106 		p9_req_put(clnt, req);
1107 		goto error;
1108 	}
1109 
1110 	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
1111 		 qid.type, qid.path, qid.version);
1112 
1113 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1114 
1115 	p9_req_put(clnt, req);
1116 	return fid;
1117 
1118 error:
1119 	if (fid)
1120 		p9_fid_destroy(fid);
1121 	return ERR_PTR(err);
1122 }
1123 EXPORT_SYMBOL(p9_client_attach);
1124 
1125 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
1126 			      const unsigned char * const *wnames, int clone)
1127 {
1128 	int err;
1129 	struct p9_client *clnt;
1130 	struct p9_fid *fid;
1131 	struct p9_qid *wqids;
1132 	struct p9_req_t *req;
1133 	u16 nwqids, count;
1134 
1135 	err = 0;
1136 	wqids = NULL;
1137 	clnt = oldfid->clnt;
1138 	if (clone) {
1139 		fid = p9_fid_create(clnt);
1140 		if (!fid) {
1141 			err = -ENOMEM;
1142 			goto error;
1143 		}
1144 
1145 		fid->uid = oldfid->uid;
1146 	} else {
1147 		fid = oldfid;
1148 	}
1149 
1150 	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
1151 		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
1152 	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
1153 			    nwname, wnames);
1154 	if (IS_ERR(req)) {
1155 		err = PTR_ERR(req);
1156 		goto error;
1157 	}
1158 
1159 	err = p9pdu_readf(&req->rc, clnt->proto_version, "R", &nwqids, &wqids);
1160 	if (err) {
1161 		trace_9p_protocol_dump(clnt, &req->rc);
1162 		p9_req_put(clnt, req);
1163 		goto clunk_fid;
1164 	}
1165 	p9_req_put(clnt, req);
1166 
1167 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
1168 
1169 	if (nwqids != nwname) {
1170 		err = -ENOENT;
1171 		goto clunk_fid;
1172 	}
1173 
1174 	for (count = 0; count < nwqids; count++)
1175 		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
1176 			 count, wqids[count].type,
1177 			 wqids[count].path,
1178 			 wqids[count].version);
1179 
1180 	if (nwname)
1181 		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
1182 	else
1183 		memmove(&fid->qid, &oldfid->qid, sizeof(struct p9_qid));
1184 
1185 	kfree(wqids);
1186 	return fid;
1187 
1188 clunk_fid:
1189 	kfree(wqids);
1190 	p9_fid_put(fid);
1191 	fid = NULL;
1192 
1193 error:
1194 	if (fid && fid != oldfid)
1195 		p9_fid_destroy(fid);
1196 
1197 	return ERR_PTR(err);
1198 }
1199 EXPORT_SYMBOL(p9_client_walk);
1200 
1201 int p9_client_open(struct p9_fid *fid, int mode)
1202 {
1203 	int err;
1204 	struct p9_client *clnt;
1205 	struct p9_req_t *req;
1206 	struct p9_qid qid;
1207 	int iounit;
1208 
1209 	clnt = fid->clnt;
1210 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1211 		 p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1212 	err = 0;
1213 
1214 	if (fid->mode != -1)
1215 		return -EINVAL;
1216 
1217 	if (p9_is_proto_dotl(clnt))
1218 		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode);
1219 	else
1220 		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
1221 	if (IS_ERR(req)) {
1222 		err = PTR_ERR(req);
1223 		goto error;
1224 	}
1225 
1226 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1227 	if (err) {
1228 		trace_9p_protocol_dump(clnt, &req->rc);
1229 		goto free_and_error;
1230 	}
1231 
1232 	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1233 		 p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1234 		 qid.path, qid.version, iounit);
1235 
1236 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1237 	fid->mode = mode;
1238 	fid->iounit = iounit;
1239 
1240 free_and_error:
1241 	p9_req_put(clnt, req);
1242 error:
1243 	return err;
1244 }
1245 EXPORT_SYMBOL(p9_client_open);
1246 
1247 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags,
1248 			  u32 mode, kgid_t gid, struct p9_qid *qid)
1249 {
1250 	int err = 0;
1251 	struct p9_client *clnt;
1252 	struct p9_req_t *req;
1253 	int iounit;
1254 
1255 	p9_debug(P9_DEBUG_9P,
1256 		 ">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1257 		 ofid->fid, name, flags, mode,
1258 		 from_kgid(&init_user_ns, gid));
1259 	clnt = ofid->clnt;
1260 
1261 	if (ofid->mode != -1)
1262 		return -EINVAL;
1263 
1264 	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
1265 			    mode, gid);
1266 	if (IS_ERR(req)) {
1267 		err = PTR_ERR(req);
1268 		goto error;
1269 	}
1270 
1271 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", qid, &iounit);
1272 	if (err) {
1273 		trace_9p_protocol_dump(clnt, &req->rc);
1274 		goto free_and_error;
1275 	}
1276 
1277 	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1278 		 qid->type, qid->path, qid->version, iounit);
1279 
1280 	memmove(&ofid->qid, qid, sizeof(struct p9_qid));
1281 	ofid->mode = mode;
1282 	ofid->iounit = iounit;
1283 
1284 free_and_error:
1285 	p9_req_put(clnt, req);
1286 error:
1287 	return err;
1288 }
1289 EXPORT_SYMBOL(p9_client_create_dotl);
1290 
1291 int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
1292 		     char *extension)
1293 {
1294 	int err;
1295 	struct p9_client *clnt;
1296 	struct p9_req_t *req;
1297 	struct p9_qid qid;
1298 	int iounit;
1299 
1300 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1301 		 fid->fid, name, perm, mode);
1302 	err = 0;
1303 	clnt = fid->clnt;
1304 
1305 	if (fid->mode != -1)
1306 		return -EINVAL;
1307 
1308 	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1309 			    mode, extension);
1310 	if (IS_ERR(req)) {
1311 		err = PTR_ERR(req);
1312 		goto error;
1313 	}
1314 
1315 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1316 	if (err) {
1317 		trace_9p_protocol_dump(clnt, &req->rc);
1318 		goto free_and_error;
1319 	}
1320 
1321 	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1322 		 qid.type, qid.path, qid.version, iounit);
1323 
1324 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
1325 	fid->mode = mode;
1326 	fid->iounit = iounit;
1327 
1328 free_and_error:
1329 	p9_req_put(clnt, req);
1330 error:
1331 	return err;
1332 }
1333 EXPORT_SYMBOL(p9_client_fcreate);
1334 
1335 int p9_client_symlink(struct p9_fid *dfid, const char *name,
1336 		      const char *symtgt, kgid_t gid, struct p9_qid *qid)
1337 {
1338 	int err = 0;
1339 	struct p9_client *clnt;
1340 	struct p9_req_t *req;
1341 
1342 	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1343 		 dfid->fid, name, symtgt);
1344 	clnt = dfid->clnt;
1345 
1346 	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
1347 			    gid);
1348 	if (IS_ERR(req)) {
1349 		err = PTR_ERR(req);
1350 		goto error;
1351 	}
1352 
1353 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
1354 	if (err) {
1355 		trace_9p_protocol_dump(clnt, &req->rc);
1356 		goto free_and_error;
1357 	}
1358 
1359 	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1360 		 qid->type, qid->path, qid->version);
1361 
1362 free_and_error:
1363 	p9_req_put(clnt, req);
1364 error:
1365 	return err;
1366 }
1367 EXPORT_SYMBOL(p9_client_symlink);
1368 
1369 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
1370 {
1371 	struct p9_client *clnt;
1372 	struct p9_req_t *req;
1373 
1374 	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1375 		 dfid->fid, oldfid->fid, newname);
1376 	clnt = dfid->clnt;
1377 	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1378 			    newname);
1379 	if (IS_ERR(req))
1380 		return PTR_ERR(req);
1381 
1382 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
1383 	p9_req_put(clnt, req);
1384 	return 0;
1385 }
1386 EXPORT_SYMBOL(p9_client_link);
1387 
1388 int p9_client_fsync(struct p9_fid *fid, int datasync)
1389 {
1390 	int err;
1391 	struct p9_client *clnt;
1392 	struct p9_req_t *req;
1393 
1394 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1395 		 fid->fid, datasync);
1396 	err = 0;
1397 	clnt = fid->clnt;
1398 
1399 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1400 	if (IS_ERR(req)) {
1401 		err = PTR_ERR(req);
1402 		goto error;
1403 	}
1404 
1405 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1406 
1407 	p9_req_put(clnt, req);
1408 
1409 error:
1410 	return err;
1411 }
1412 EXPORT_SYMBOL(p9_client_fsync);
1413 
1414 int p9_client_clunk(struct p9_fid *fid)
1415 {
1416 	int err;
1417 	struct p9_client *clnt;
1418 	struct p9_req_t *req;
1419 	int retries = 0;
1420 
1421 again:
1422 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n",
1423 		 fid->fid, retries);
1424 	err = 0;
1425 	clnt = fid->clnt;
1426 
1427 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1428 	if (IS_ERR(req)) {
1429 		err = PTR_ERR(req);
1430 		goto error;
1431 	}
1432 
1433 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1434 
1435 	p9_req_put(clnt, req);
1436 error:
1437 	/* Fid is not valid even after a failed clunk
1438 	 * If interrupted, retry once then give up and
1439 	 * leak fid until umount.
1440 	 */
1441 	if (err == -ERESTARTSYS) {
1442 		if (retries++ == 0)
1443 			goto again;
1444 	} else {
1445 		p9_fid_destroy(fid);
1446 	}
1447 	return err;
1448 }
1449 EXPORT_SYMBOL(p9_client_clunk);
1450 
1451 int p9_client_remove(struct p9_fid *fid)
1452 {
1453 	int err;
1454 	struct p9_client *clnt;
1455 	struct p9_req_t *req;
1456 
1457 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1458 	err = 0;
1459 	clnt = fid->clnt;
1460 
1461 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1462 	if (IS_ERR(req)) {
1463 		err = PTR_ERR(req);
1464 		goto error;
1465 	}
1466 
1467 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1468 
1469 	p9_req_put(clnt, req);
1470 error:
1471 	if (err == -ERESTARTSYS)
1472 		p9_fid_put(fid);
1473 	else
1474 		p9_fid_destroy(fid);
1475 	return err;
1476 }
1477 EXPORT_SYMBOL(p9_client_remove);
1478 
1479 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
1480 {
1481 	int err = 0;
1482 	struct p9_req_t *req;
1483 	struct p9_client *clnt;
1484 
1485 	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
1486 		 dfid->fid, name, flags);
1487 
1488 	clnt = dfid->clnt;
1489 	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
1490 	if (IS_ERR(req)) {
1491 		err = PTR_ERR(req);
1492 		goto error;
1493 	}
1494 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
1495 
1496 	p9_req_put(clnt, req);
1497 error:
1498 	return err;
1499 }
1500 EXPORT_SYMBOL(p9_client_unlinkat);
1501 
1502 int
1503 p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
1504 {
1505 	int total = 0;
1506 	*err = 0;
1507 
1508 	while (iov_iter_count(to)) {
1509 		int count;
1510 
1511 		count = p9_client_read_once(fid, offset, to, err);
1512 		if (!count || *err)
1513 			break;
1514 		offset += count;
1515 		total += count;
1516 	}
1517 	return total;
1518 }
1519 EXPORT_SYMBOL(p9_client_read);
1520 
1521 int
1522 p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
1523 		    int *err)
1524 {
1525 	struct p9_client *clnt = fid->clnt;
1526 	struct p9_req_t *req;
1527 	int count = iov_iter_count(to);
1528 	int rsize, received, non_zc = 0;
1529 	char *dataptr;
1530 
1531 	*err = 0;
1532 	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %zu\n",
1533 		 fid->fid, offset, iov_iter_count(to));
1534 
1535 	rsize = fid->iounit;
1536 	if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1537 		rsize = clnt->msize - P9_IOHDRSZ;
1538 
1539 	if (count < rsize)
1540 		rsize = count;
1541 
1542 	/* Don't bother zerocopy for small IO (< 1024) */
1543 	if (clnt->trans_mod->zc_request && rsize > 1024) {
1544 		/* response header len is 11
1545 		 * PDU Header(7) + IO Size (4)
1546 		 */
1547 		req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
1548 				       0, 11, "dqd", fid->fid,
1549 				       offset, rsize);
1550 	} else {
1551 		non_zc = 1;
1552 		req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1553 				    rsize);
1554 	}
1555 	if (IS_ERR(req)) {
1556 		*err = PTR_ERR(req);
1557 		if (!non_zc)
1558 			iov_iter_revert(to, count - iov_iter_count(to));
1559 		return 0;
1560 	}
1561 
1562 	*err = p9pdu_readf(&req->rc, clnt->proto_version,
1563 			   "D", &received, &dataptr);
1564 	if (*err) {
1565 		if (!non_zc)
1566 			iov_iter_revert(to, count - iov_iter_count(to));
1567 		trace_9p_protocol_dump(clnt, &req->rc);
1568 		p9_req_put(clnt, req);
1569 		return 0;
1570 	}
1571 	if (rsize < received) {
1572 		pr_err("bogus RREAD count (%d > %d)\n", received, rsize);
1573 		received = rsize;
1574 	}
1575 
1576 	p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1577 
1578 	if (non_zc) {
1579 		int n = copy_to_iter(dataptr, received, to);
1580 
1581 		if (n != received) {
1582 			*err = -EFAULT;
1583 			p9_req_put(clnt, req);
1584 			return n;
1585 		}
1586 	} else {
1587 		iov_iter_revert(to, count - received - iov_iter_count(to));
1588 	}
1589 	p9_req_put(clnt, req);
1590 	return received;
1591 }
1592 EXPORT_SYMBOL(p9_client_read_once);
1593 
1594 int
1595 p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
1596 {
1597 	struct p9_client *clnt = fid->clnt;
1598 	struct p9_req_t *req;
1599 	int total = 0;
1600 	*err = 0;
1601 
1602 	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n",
1603 		 fid->fid, offset, iov_iter_count(from));
1604 
1605 	while (iov_iter_count(from)) {
1606 		int count = iov_iter_count(from);
1607 		int rsize = fid->iounit;
1608 		int written;
1609 
1610 		if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
1611 			rsize = clnt->msize - P9_IOHDRSZ;
1612 
1613 		if (count < rsize)
1614 			rsize = count;
1615 
1616 		/* Don't bother zerocopy for small IO (< 1024) */
1617 		if (clnt->trans_mod->zc_request && rsize > 1024) {
1618 			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
1619 					       rsize, P9_ZC_HDR_SZ, "dqd",
1620 					       fid->fid, offset, rsize);
1621 		} else {
1622 			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1623 					    offset, rsize, from);
1624 		}
1625 		if (IS_ERR(req)) {
1626 			iov_iter_revert(from, count - iov_iter_count(from));
1627 			*err = PTR_ERR(req);
1628 			break;
1629 		}
1630 
1631 		*err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &written);
1632 		if (*err) {
1633 			iov_iter_revert(from, count - iov_iter_count(from));
1634 			trace_9p_protocol_dump(clnt, &req->rc);
1635 			p9_req_put(clnt, req);
1636 			break;
1637 		}
1638 		if (rsize < written) {
1639 			pr_err("bogus RWRITE count (%d > %d)\n", written, rsize);
1640 			written = rsize;
1641 		}
1642 
1643 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1644 
1645 		p9_req_put(clnt, req);
1646 		iov_iter_revert(from, count - written - iov_iter_count(from));
1647 		total += written;
1648 		offset += written;
1649 	}
1650 	return total;
1651 }
1652 EXPORT_SYMBOL(p9_client_write);
1653 
1654 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1655 {
1656 	int err;
1657 	struct p9_client *clnt;
1658 	struct p9_wstat *ret;
1659 	struct p9_req_t *req;
1660 	u16 ignored;
1661 
1662 	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1663 
1664 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1665 	if (!ret)
1666 		return ERR_PTR(-ENOMEM);
1667 
1668 	err = 0;
1669 	clnt = fid->clnt;
1670 
1671 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1672 	if (IS_ERR(req)) {
1673 		err = PTR_ERR(req);
1674 		goto error;
1675 	}
1676 
1677 	err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
1678 	if (err) {
1679 		trace_9p_protocol_dump(clnt, &req->rc);
1680 		p9_req_put(clnt, req);
1681 		goto error;
1682 	}
1683 
1684 	p9_debug(P9_DEBUG_9P,
1685 		 "<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1686 		 "<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1687 		 "<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1688 		 "<<<    uid=%d gid=%d n_muid=%d\n",
1689 		 ret->size, ret->type, ret->dev, ret->qid.type, ret->qid.path,
1690 		 ret->qid.version, ret->mode,
1691 		 ret->atime, ret->mtime, ret->length,
1692 		 ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1693 		 from_kuid(&init_user_ns, ret->n_uid),
1694 		 from_kgid(&init_user_ns, ret->n_gid),
1695 		 from_kuid(&init_user_ns, ret->n_muid));
1696 
1697 	p9_req_put(clnt, req);
1698 	return ret;
1699 
1700 error:
1701 	kfree(ret);
1702 	return ERR_PTR(err);
1703 }
1704 EXPORT_SYMBOL(p9_client_stat);
1705 
1706 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1707 					    u64 request_mask)
1708 {
1709 	int err;
1710 	struct p9_client *clnt;
1711 	struct p9_stat_dotl *ret;
1712 	struct p9_req_t *req;
1713 
1714 	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1715 		 fid->fid, request_mask);
1716 
1717 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
1718 	if (!ret)
1719 		return ERR_PTR(-ENOMEM);
1720 
1721 	err = 0;
1722 	clnt = fid->clnt;
1723 
1724 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1725 	if (IS_ERR(req)) {
1726 		err = PTR_ERR(req);
1727 		goto error;
1728 	}
1729 
1730 	err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
1731 	if (err) {
1732 		trace_9p_protocol_dump(clnt, &req->rc);
1733 		p9_req_put(clnt, req);
1734 		goto error;
1735 	}
1736 
1737 	p9_debug(P9_DEBUG_9P, "<<< RGETATTR st_result_mask=%lld\n"
1738 		 "<<< qid=%x.%llx.%x\n"
1739 		 "<<< st_mode=%8.8x st_nlink=%llu\n"
1740 		 "<<< st_uid=%d st_gid=%d\n"
1741 		 "<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1742 		 "<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1743 		 "<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1744 		 "<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1745 		 "<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1746 		 "<<< st_gen=%lld st_data_version=%lld\n",
1747 		 ret->st_result_mask,
1748 		 ret->qid.type, ret->qid.path, ret->qid.version,
1749 		 ret->st_mode, ret->st_nlink,
1750 		 from_kuid(&init_user_ns, ret->st_uid),
1751 		 from_kgid(&init_user_ns, ret->st_gid),
1752 		 ret->st_rdev, ret->st_size, ret->st_blksize, ret->st_blocks,
1753 		 ret->st_atime_sec, ret->st_atime_nsec,
1754 		 ret->st_mtime_sec, ret->st_mtime_nsec,
1755 		 ret->st_ctime_sec, ret->st_ctime_nsec,
1756 		 ret->st_btime_sec, ret->st_btime_nsec,
1757 		 ret->st_gen, ret->st_data_version);
1758 
1759 	p9_req_put(clnt, req);
1760 	return ret;
1761 
1762 error:
1763 	kfree(ret);
1764 	return ERR_PTR(err);
1765 }
1766 EXPORT_SYMBOL(p9_client_getattr_dotl);
1767 
1768 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1769 {
1770 	int ret;
1771 
1772 	/* NOTE: size shouldn't include its own length */
1773 	/* size[2] type[2] dev[4] qid[13] */
1774 	/* mode[4] atime[4] mtime[4] length[8]*/
1775 	/* name[s] uid[s] gid[s] muid[s] */
1776 	ret = 2 + 4 + 13 + 4 + 4 + 4 + 8 + 2 + 2 + 2 + 2;
1777 
1778 	if (wst->name)
1779 		ret += strlen(wst->name);
1780 	if (wst->uid)
1781 		ret += strlen(wst->uid);
1782 	if (wst->gid)
1783 		ret += strlen(wst->gid);
1784 	if (wst->muid)
1785 		ret += strlen(wst->muid);
1786 
1787 	if (proto_version == p9_proto_2000u ||
1788 	    proto_version == p9_proto_2000L) {
1789 		/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1790 		ret += 2 + 4 + 4 + 4;
1791 		if (wst->extension)
1792 			ret += strlen(wst->extension);
1793 	}
1794 
1795 	return ret;
1796 }
1797 
1798 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1799 {
1800 	int err;
1801 	struct p9_req_t *req;
1802 	struct p9_client *clnt;
1803 
1804 	err = 0;
1805 	clnt = fid->clnt;
1806 	wst->size = p9_client_statsize(wst, clnt->proto_version);
1807 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n",
1808 		 fid->fid);
1809 	p9_debug(P9_DEBUG_9P,
1810 		 "     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1811 		 "     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1812 		 "     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1813 		 "     uid=%d gid=%d n_muid=%d\n",
1814 		 wst->size, wst->type, wst->dev, wst->qid.type,
1815 		 wst->qid.path, wst->qid.version,
1816 		 wst->mode, wst->atime, wst->mtime, wst->length,
1817 		 wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1818 		 from_kuid(&init_user_ns, wst->n_uid),
1819 		 from_kgid(&init_user_ns, wst->n_gid),
1820 		 from_kuid(&init_user_ns, wst->n_muid));
1821 
1822 	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS",
1823 			    fid->fid, wst->size + 2, wst);
1824 	if (IS_ERR(req)) {
1825 		err = PTR_ERR(req);
1826 		goto error;
1827 	}
1828 
1829 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1830 
1831 	p9_req_put(clnt, req);
1832 error:
1833 	return err;
1834 }
1835 EXPORT_SYMBOL(p9_client_wstat);
1836 
1837 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1838 {
1839 	int err;
1840 	struct p9_req_t *req;
1841 	struct p9_client *clnt;
1842 
1843 	err = 0;
1844 	clnt = fid->clnt;
1845 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1846 	p9_debug(P9_DEBUG_9P, "    valid=%x mode=%x uid=%d gid=%d size=%lld\n",
1847 		 p9attr->valid, p9attr->mode,
1848 		 from_kuid(&init_user_ns, p9attr->uid),
1849 		 from_kgid(&init_user_ns, p9attr->gid),
1850 		 p9attr->size);
1851 	p9_debug(P9_DEBUG_9P, "    atime_sec=%lld atime_nsec=%lld\n",
1852 		 p9attr->atime_sec, p9attr->atime_nsec);
1853 	p9_debug(P9_DEBUG_9P, "    mtime_sec=%lld mtime_nsec=%lld\n",
1854 		 p9attr->mtime_sec, p9attr->mtime_nsec);
1855 
1856 	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1857 
1858 	if (IS_ERR(req)) {
1859 		err = PTR_ERR(req);
1860 		goto error;
1861 	}
1862 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1863 	p9_req_put(clnt, req);
1864 error:
1865 	return err;
1866 }
1867 EXPORT_SYMBOL(p9_client_setattr);
1868 
1869 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1870 {
1871 	int err;
1872 	struct p9_req_t *req;
1873 	struct p9_client *clnt;
1874 
1875 	err = 0;
1876 	clnt = fid->clnt;
1877 
1878 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1879 
1880 	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1881 	if (IS_ERR(req)) {
1882 		err = PTR_ERR(req);
1883 		goto error;
1884 	}
1885 
1886 	err = p9pdu_readf(&req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1887 			  &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1888 			  &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1889 	if (err) {
1890 		trace_9p_protocol_dump(clnt, &req->rc);
1891 		p9_req_put(clnt, req);
1892 		goto error;
1893 	}
1894 
1895 	p9_debug(P9_DEBUG_9P,
1896 		 "<<< RSTATFS fid %d type 0x%x bsize %u blocks %llu bfree %llu bavail %llu files %llu ffree %llu fsid %llu namelen %u\n",
1897 		 fid->fid, sb->type, sb->bsize, sb->blocks, sb->bfree,
1898 		 sb->bavail, sb->files, sb->ffree, sb->fsid, sb->namelen);
1899 
1900 	p9_req_put(clnt, req);
1901 error:
1902 	return err;
1903 }
1904 EXPORT_SYMBOL(p9_client_statfs);
1905 
1906 int p9_client_rename(struct p9_fid *fid,
1907 		     struct p9_fid *newdirfid, const char *name)
1908 {
1909 	int err;
1910 	struct p9_req_t *req;
1911 	struct p9_client *clnt;
1912 
1913 	err = 0;
1914 	clnt = fid->clnt;
1915 
1916 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1917 		 fid->fid, newdirfid->fid, name);
1918 
1919 	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1920 			    newdirfid->fid, name);
1921 	if (IS_ERR(req)) {
1922 		err = PTR_ERR(req);
1923 		goto error;
1924 	}
1925 
1926 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1927 
1928 	p9_req_put(clnt, req);
1929 error:
1930 	return err;
1931 }
1932 EXPORT_SYMBOL(p9_client_rename);
1933 
1934 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
1935 		       struct p9_fid *newdirfid, const char *new_name)
1936 {
1937 	int err;
1938 	struct p9_req_t *req;
1939 	struct p9_client *clnt;
1940 
1941 	err = 0;
1942 	clnt = olddirfid->clnt;
1943 
1944 	p9_debug(P9_DEBUG_9P,
1945 		 ">>> TRENAMEAT olddirfid %d old name %s newdirfid %d new name %s\n",
1946 		 olddirfid->fid, old_name, newdirfid->fid, new_name);
1947 
1948 	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
1949 			    old_name, newdirfid->fid, new_name);
1950 	if (IS_ERR(req)) {
1951 		err = PTR_ERR(req);
1952 		goto error;
1953 	}
1954 
1955 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
1956 		 newdirfid->fid, new_name);
1957 
1958 	p9_req_put(clnt, req);
1959 error:
1960 	return err;
1961 }
1962 EXPORT_SYMBOL(p9_client_renameat);
1963 
1964 /* An xattrwalk without @attr_name gives the fid for the lisxattr namespace
1965  */
1966 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
1967 				   const char *attr_name, u64 *attr_size)
1968 {
1969 	int err;
1970 	struct p9_req_t *req;
1971 	struct p9_client *clnt;
1972 	struct p9_fid *attr_fid;
1973 
1974 	err = 0;
1975 	clnt = file_fid->clnt;
1976 	attr_fid = p9_fid_create(clnt);
1977 	if (!attr_fid) {
1978 		err = -ENOMEM;
1979 		goto error;
1980 	}
1981 	p9_debug(P9_DEBUG_9P,
1982 		 ">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
1983 		 file_fid->fid, attr_fid->fid, attr_name);
1984 
1985 	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
1986 			    file_fid->fid, attr_fid->fid, attr_name);
1987 	if (IS_ERR(req)) {
1988 		err = PTR_ERR(req);
1989 		goto error;
1990 	}
1991 	err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
1992 	if (err) {
1993 		trace_9p_protocol_dump(clnt, &req->rc);
1994 		p9_req_put(clnt, req);
1995 		goto clunk_fid;
1996 	}
1997 	p9_req_put(clnt, req);
1998 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
1999 		 attr_fid->fid, *attr_size);
2000 	return attr_fid;
2001 clunk_fid:
2002 	p9_fid_put(attr_fid);
2003 	attr_fid = NULL;
2004 error:
2005 	if (attr_fid && attr_fid != file_fid)
2006 		p9_fid_destroy(attr_fid);
2007 
2008 	return ERR_PTR(err);
2009 }
2010 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
2011 
2012 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
2013 			  u64 attr_size, int flags)
2014 {
2015 	int err;
2016 	struct p9_req_t *req;
2017 	struct p9_client *clnt;
2018 
2019 	p9_debug(P9_DEBUG_9P,
2020 		 ">>> TXATTRCREATE fid %d name  %s size %llu flag %d\n",
2021 		 fid->fid, name, attr_size, flags);
2022 	err = 0;
2023 	clnt = fid->clnt;
2024 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
2025 			    fid->fid, name, attr_size, flags);
2026 	if (IS_ERR(req)) {
2027 		err = PTR_ERR(req);
2028 		goto error;
2029 	}
2030 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
2031 	p9_req_put(clnt, req);
2032 error:
2033 	return err;
2034 }
2035 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
2036 
2037 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
2038 {
2039 	int err, rsize, non_zc = 0;
2040 	struct p9_client *clnt;
2041 	struct p9_req_t *req;
2042 	char *dataptr;
2043 	struct kvec kv = {.iov_base = data, .iov_len = count};
2044 	struct iov_iter to;
2045 
2046 	iov_iter_kvec(&to, READ, &kv, 1, count);
2047 
2048 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
2049 		 fid->fid, offset, count);
2050 
2051 	err = 0;
2052 	clnt = fid->clnt;
2053 
2054 	rsize = fid->iounit;
2055 	if (!rsize || rsize > clnt->msize - P9_READDIRHDRSZ)
2056 		rsize = clnt->msize - P9_READDIRHDRSZ;
2057 
2058 	if (count < rsize)
2059 		rsize = count;
2060 
2061 	/* Don't bother zerocopy for small IO (< 1024) */
2062 	if (clnt->trans_mod->zc_request && rsize > 1024) {
2063 		/* response header len is 11
2064 		 * PDU Header(7) + IO Size (4)
2065 		 */
2066 		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2067 				       11, "dqd", fid->fid, offset, rsize);
2068 	} else {
2069 		non_zc = 1;
2070 		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
2071 				    offset, rsize);
2072 	}
2073 	if (IS_ERR(req)) {
2074 		err = PTR_ERR(req);
2075 		goto error;
2076 	}
2077 
2078 	err = p9pdu_readf(&req->rc, clnt->proto_version, "D", &count, &dataptr);
2079 	if (err) {
2080 		trace_9p_protocol_dump(clnt, &req->rc);
2081 		goto free_and_error;
2082 	}
2083 	if (rsize < count) {
2084 		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
2085 		count = rsize;
2086 	}
2087 
2088 	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
2089 
2090 	if (non_zc)
2091 		memmove(data, dataptr, count);
2092 
2093 	p9_req_put(clnt, req);
2094 	return count;
2095 
2096 free_and_error:
2097 	p9_req_put(clnt, req);
2098 error:
2099 	return err;
2100 }
2101 EXPORT_SYMBOL(p9_client_readdir);
2102 
2103 int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
2104 			 dev_t rdev, kgid_t gid, struct p9_qid *qid)
2105 {
2106 	int err;
2107 	struct p9_client *clnt;
2108 	struct p9_req_t *req;
2109 
2110 	err = 0;
2111 	clnt = fid->clnt;
2112 	p9_debug(P9_DEBUG_9P,
2113 		 ">>> TMKNOD fid %d name %s mode %d major %d minor %d\n",
2114 		 fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
2115 	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
2116 			    MAJOR(rdev), MINOR(rdev), gid);
2117 	if (IS_ERR(req))
2118 		return PTR_ERR(req);
2119 
2120 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2121 	if (err) {
2122 		trace_9p_protocol_dump(clnt, &req->rc);
2123 		goto error;
2124 	}
2125 	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n",
2126 		 qid->type, qid->path, qid->version);
2127 
2128 error:
2129 	p9_req_put(clnt, req);
2130 	return err;
2131 }
2132 EXPORT_SYMBOL(p9_client_mknod_dotl);
2133 
2134 int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
2135 			 kgid_t gid, struct p9_qid *qid)
2136 {
2137 	int err;
2138 	struct p9_client *clnt;
2139 	struct p9_req_t *req;
2140 
2141 	err = 0;
2142 	clnt = fid->clnt;
2143 	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
2144 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
2145 	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg",
2146 			    fid->fid, name, mode, gid);
2147 	if (IS_ERR(req))
2148 		return PTR_ERR(req);
2149 
2150 	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
2151 	if (err) {
2152 		trace_9p_protocol_dump(clnt, &req->rc);
2153 		goto error;
2154 	}
2155 	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
2156 		 qid->path, qid->version);
2157 
2158 error:
2159 	p9_req_put(clnt, req);
2160 	return err;
2161 }
2162 EXPORT_SYMBOL(p9_client_mkdir_dotl);
2163 
2164 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
2165 {
2166 	int err;
2167 	struct p9_client *clnt;
2168 	struct p9_req_t *req;
2169 
2170 	err = 0;
2171 	clnt = fid->clnt;
2172 	p9_debug(P9_DEBUG_9P,
2173 		 ">>> TLOCK fid %d type %i flags %d start %lld length %lld proc_id %d client_id %s\n",
2174 		 fid->fid, flock->type, flock->flags, flock->start,
2175 		 flock->length, flock->proc_id, flock->client_id);
2176 
2177 	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
2178 			    flock->flags, flock->start, flock->length,
2179 			    flock->proc_id, flock->client_id);
2180 
2181 	if (IS_ERR(req))
2182 		return PTR_ERR(req);
2183 
2184 	err = p9pdu_readf(&req->rc, clnt->proto_version, "b", status);
2185 	if (err) {
2186 		trace_9p_protocol_dump(clnt, &req->rc);
2187 		goto error;
2188 	}
2189 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
2190 error:
2191 	p9_req_put(clnt, req);
2192 	return err;
2193 }
2194 EXPORT_SYMBOL(p9_client_lock_dotl);
2195 
2196 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
2197 {
2198 	int err;
2199 	struct p9_client *clnt;
2200 	struct p9_req_t *req;
2201 
2202 	err = 0;
2203 	clnt = fid->clnt;
2204 	p9_debug(P9_DEBUG_9P,
2205 		 ">>> TGETLOCK fid %d, type %i start %lld length %lld proc_id %d client_id %s\n",
2206 		 fid->fid, glock->type, glock->start, glock->length,
2207 		 glock->proc_id, glock->client_id);
2208 
2209 	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,
2210 			    glock->type, glock->start, glock->length,
2211 			    glock->proc_id, glock->client_id);
2212 
2213 	if (IS_ERR(req))
2214 		return PTR_ERR(req);
2215 
2216 	err = p9pdu_readf(&req->rc, clnt->proto_version, "bqqds", &glock->type,
2217 			  &glock->start, &glock->length, &glock->proc_id,
2218 			  &glock->client_id);
2219 	if (err) {
2220 		trace_9p_protocol_dump(clnt, &req->rc);
2221 		goto error;
2222 	}
2223 	p9_debug(P9_DEBUG_9P,
2224 		 "<<< RGETLOCK type %i start %lld length %lld proc_id %d client_id %s\n",
2225 		 glock->type, glock->start, glock->length,
2226 		 glock->proc_id, glock->client_id);
2227 error:
2228 	p9_req_put(clnt, req);
2229 	return err;
2230 }
2231 EXPORT_SYMBOL(p9_client_getlock_dotl);
2232 
2233 int p9_client_readlink(struct p9_fid *fid, char **target)
2234 {
2235 	int err;
2236 	struct p9_client *clnt;
2237 	struct p9_req_t *req;
2238 
2239 	err = 0;
2240 	clnt = fid->clnt;
2241 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
2242 
2243 	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
2244 	if (IS_ERR(req))
2245 		return PTR_ERR(req);
2246 
2247 	err = p9pdu_readf(&req->rc, clnt->proto_version, "s", target);
2248 	if (err) {
2249 		trace_9p_protocol_dump(clnt, &req->rc);
2250 		goto error;
2251 	}
2252 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
2253 error:
2254 	p9_req_put(clnt, req);
2255 	return err;
2256 }
2257 EXPORT_SYMBOL(p9_client_readlink);
2258 
2259 int __init p9_client_init(void)
2260 {
2261 	p9_req_cache = KMEM_CACHE(p9_req_t, SLAB_TYPESAFE_BY_RCU);
2262 	return p9_req_cache ? 0 : -ENOMEM;
2263 }
2264 
2265 void __exit p9_client_exit(void)
2266 {
2267 	kmem_cache_destroy(p9_req_cache);
2268 }
2269