xref: /openbmc/linux/fs/9p/vfs_inode.c (revision 81d67439)
1 /*
2  *  linux/fs/9p/vfs_inode.c
3  *
4  * This file contains vfs inode ops for the 9P2000 protocol.
5  *
6  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
7  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
8  *
9  *  This program is free software; you can redistribute it and/or modify
10  *  it under the terms of the GNU General Public License version 2
11  *  as published by the Free Software Foundation.
12  *
13  *  This program is distributed in the hope that it will be useful,
14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  *  GNU General Public License for more details.
17  *
18  *  You should have received a copy of the GNU General Public License
19  *  along with this program; if not, write to:
20  *  Free Software Foundation
21  *  51 Franklin Street, Fifth Floor
22  *  Boston, MA  02111-1301  USA
23  *
24  */
25 
26 #include <linux/module.h>
27 #include <linux/errno.h>
28 #include <linux/fs.h>
29 #include <linux/file.h>
30 #include <linux/pagemap.h>
31 #include <linux/stat.h>
32 #include <linux/string.h>
33 #include <linux/inet.h>
34 #include <linux/namei.h>
35 #include <linux/idr.h>
36 #include <linux/sched.h>
37 #include <linux/slab.h>
38 #include <linux/xattr.h>
39 #include <linux/posix_acl.h>
40 #include <net/9p/9p.h>
41 #include <net/9p/client.h>
42 
43 #include "v9fs.h"
44 #include "v9fs_vfs.h"
45 #include "fid.h"
46 #include "cache.h"
47 #include "xattr.h"
48 #include "acl.h"
49 
50 static const struct inode_operations v9fs_dir_inode_operations;
51 static const struct inode_operations v9fs_dir_inode_operations_dotu;
52 static const struct inode_operations v9fs_file_inode_operations;
53 static const struct inode_operations v9fs_symlink_inode_operations;
54 
55 /**
56  * unixmode2p9mode - convert unix mode bits to plan 9
57  * @v9ses: v9fs session information
58  * @mode: mode to convert
59  *
60  */
61 
62 static int unixmode2p9mode(struct v9fs_session_info *v9ses, int mode)
63 {
64 	int res;
65 	res = mode & 0777;
66 	if (S_ISDIR(mode))
67 		res |= P9_DMDIR;
68 	if (v9fs_proto_dotu(v9ses)) {
69 		if (S_ISLNK(mode))
70 			res |= P9_DMSYMLINK;
71 		if (v9ses->nodev == 0) {
72 			if (S_ISSOCK(mode))
73 				res |= P9_DMSOCKET;
74 			if (S_ISFIFO(mode))
75 				res |= P9_DMNAMEDPIPE;
76 			if (S_ISBLK(mode))
77 				res |= P9_DMDEVICE;
78 			if (S_ISCHR(mode))
79 				res |= P9_DMDEVICE;
80 		}
81 
82 		if ((mode & S_ISUID) == S_ISUID)
83 			res |= P9_DMSETUID;
84 		if ((mode & S_ISGID) == S_ISGID)
85 			res |= P9_DMSETGID;
86 		if ((mode & S_ISVTX) == S_ISVTX)
87 			res |= P9_DMSETVTX;
88 		if ((mode & P9_DMLINK))
89 			res |= P9_DMLINK;
90 	}
91 
92 	return res;
93 }
94 
95 /**
96  * p9mode2unixmode- convert plan9 mode bits to unix mode bits
97  * @v9ses: v9fs session information
98  * @mode: mode to convert
99  *
100  */
101 
102 static int p9mode2unixmode(struct v9fs_session_info *v9ses, int mode)
103 {
104 	int res;
105 
106 	res = mode & 0777;
107 
108 	if ((mode & P9_DMDIR) == P9_DMDIR)
109 		res |= S_IFDIR;
110 	else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
111 		res |= S_IFLNK;
112 	else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
113 		 && (v9ses->nodev == 0))
114 		res |= S_IFSOCK;
115 	else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
116 		 && (v9ses->nodev == 0))
117 		res |= S_IFIFO;
118 	else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
119 		 && (v9ses->nodev == 0))
120 		res |= S_IFBLK;
121 	else
122 		res |= S_IFREG;
123 
124 	if (v9fs_proto_dotu(v9ses)) {
125 		if ((mode & P9_DMSETUID) == P9_DMSETUID)
126 			res |= S_ISUID;
127 
128 		if ((mode & P9_DMSETGID) == P9_DMSETGID)
129 			res |= S_ISGID;
130 
131 		if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
132 			res |= S_ISVTX;
133 	}
134 
135 	return res;
136 }
137 
138 /**
139  * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
140  * @uflags: flags to convert
141  * @extended: if .u extensions are active
142  */
143 
144 int v9fs_uflags2omode(int uflags, int extended)
145 {
146 	int ret;
147 
148 	ret = 0;
149 	switch (uflags&3) {
150 	default:
151 	case O_RDONLY:
152 		ret = P9_OREAD;
153 		break;
154 
155 	case O_WRONLY:
156 		ret = P9_OWRITE;
157 		break;
158 
159 	case O_RDWR:
160 		ret = P9_ORDWR;
161 		break;
162 	}
163 
164 	if (uflags & O_TRUNC)
165 		ret |= P9_OTRUNC;
166 
167 	if (extended) {
168 		if (uflags & O_EXCL)
169 			ret |= P9_OEXCL;
170 
171 		if (uflags & O_APPEND)
172 			ret |= P9_OAPPEND;
173 	}
174 
175 	return ret;
176 }
177 
178 /**
179  * v9fs_blank_wstat - helper function to setup a 9P stat structure
180  * @wstat: structure to initialize
181  *
182  */
183 
184 void
185 v9fs_blank_wstat(struct p9_wstat *wstat)
186 {
187 	wstat->type = ~0;
188 	wstat->dev = ~0;
189 	wstat->qid.type = ~0;
190 	wstat->qid.version = ~0;
191 	*((long long *)&wstat->qid.path) = ~0;
192 	wstat->mode = ~0;
193 	wstat->atime = ~0;
194 	wstat->mtime = ~0;
195 	wstat->length = ~0;
196 	wstat->name = NULL;
197 	wstat->uid = NULL;
198 	wstat->gid = NULL;
199 	wstat->muid = NULL;
200 	wstat->n_uid = ~0;
201 	wstat->n_gid = ~0;
202 	wstat->n_muid = ~0;
203 	wstat->extension = NULL;
204 }
205 
206 /**
207  * v9fs_alloc_inode - helper function to allocate an inode
208  *
209  */
210 struct inode *v9fs_alloc_inode(struct super_block *sb)
211 {
212 	struct v9fs_inode *v9inode;
213 	v9inode = (struct v9fs_inode *)kmem_cache_alloc(v9fs_inode_cache,
214 							GFP_KERNEL);
215 	if (!v9inode)
216 		return NULL;
217 #ifdef CONFIG_9P_FSCACHE
218 	v9inode->fscache = NULL;
219 	spin_lock_init(&v9inode->fscache_lock);
220 #endif
221 	v9inode->writeback_fid = NULL;
222 	v9inode->cache_validity = 0;
223 	mutex_init(&v9inode->v_mutex);
224 	return &v9inode->vfs_inode;
225 }
226 
227 /**
228  * v9fs_destroy_inode - destroy an inode
229  *
230  */
231 
232 static void v9fs_i_callback(struct rcu_head *head)
233 {
234 	struct inode *inode = container_of(head, struct inode, i_rcu);
235 	INIT_LIST_HEAD(&inode->i_dentry);
236 	kmem_cache_free(v9fs_inode_cache, V9FS_I(inode));
237 }
238 
239 void v9fs_destroy_inode(struct inode *inode)
240 {
241 	call_rcu(&inode->i_rcu, v9fs_i_callback);
242 }
243 
244 int v9fs_init_inode(struct v9fs_session_info *v9ses,
245 		    struct inode *inode, int mode)
246 {
247 	int err = 0;
248 
249 	inode_init_owner(inode, NULL, mode);
250 	inode->i_blocks = 0;
251 	inode->i_rdev = 0;
252 	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
253 	inode->i_mapping->a_ops = &v9fs_addr_operations;
254 
255 	switch (mode & S_IFMT) {
256 	case S_IFIFO:
257 	case S_IFBLK:
258 	case S_IFCHR:
259 	case S_IFSOCK:
260 		if (v9fs_proto_dotl(v9ses)) {
261 			inode->i_op = &v9fs_file_inode_operations_dotl;
262 			inode->i_fop = &v9fs_file_operations_dotl;
263 		} else if (v9fs_proto_dotu(v9ses)) {
264 			inode->i_op = &v9fs_file_inode_operations;
265 			inode->i_fop = &v9fs_file_operations;
266 		} else {
267 			P9_DPRINTK(P9_DEBUG_ERROR,
268 				   "special files without extended mode\n");
269 			err = -EINVAL;
270 			goto error;
271 		}
272 		init_special_inode(inode, inode->i_mode, inode->i_rdev);
273 		break;
274 	case S_IFREG:
275 		if (v9fs_proto_dotl(v9ses)) {
276 			inode->i_op = &v9fs_file_inode_operations_dotl;
277 			if (v9ses->cache)
278 				inode->i_fop =
279 					&v9fs_cached_file_operations_dotl;
280 			else
281 				inode->i_fop = &v9fs_file_operations_dotl;
282 		} else {
283 			inode->i_op = &v9fs_file_inode_operations;
284 			if (v9ses->cache)
285 				inode->i_fop = &v9fs_cached_file_operations;
286 			else
287 				inode->i_fop = &v9fs_file_operations;
288 		}
289 
290 		break;
291 	case S_IFLNK:
292 		if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
293 			P9_DPRINTK(P9_DEBUG_ERROR, "extended modes used with "
294 						"legacy protocol.\n");
295 			err = -EINVAL;
296 			goto error;
297 		}
298 
299 		if (v9fs_proto_dotl(v9ses))
300 			inode->i_op = &v9fs_symlink_inode_operations_dotl;
301 		else
302 			inode->i_op = &v9fs_symlink_inode_operations;
303 
304 		break;
305 	case S_IFDIR:
306 		inc_nlink(inode);
307 		if (v9fs_proto_dotl(v9ses))
308 			inode->i_op = &v9fs_dir_inode_operations_dotl;
309 		else if (v9fs_proto_dotu(v9ses))
310 			inode->i_op = &v9fs_dir_inode_operations_dotu;
311 		else
312 			inode->i_op = &v9fs_dir_inode_operations;
313 
314 		if (v9fs_proto_dotl(v9ses))
315 			inode->i_fop = &v9fs_dir_operations_dotl;
316 		else
317 			inode->i_fop = &v9fs_dir_operations;
318 
319 		break;
320 	default:
321 		P9_DPRINTK(P9_DEBUG_ERROR, "BAD mode 0x%x S_IFMT 0x%x\n",
322 			   mode, mode & S_IFMT);
323 		err = -EINVAL;
324 		goto error;
325 	}
326 error:
327 	return err;
328 
329 }
330 
331 /**
332  * v9fs_get_inode - helper function to setup an inode
333  * @sb: superblock
334  * @mode: mode to setup inode with
335  *
336  */
337 
338 struct inode *v9fs_get_inode(struct super_block *sb, int mode)
339 {
340 	int err;
341 	struct inode *inode;
342 	struct v9fs_session_info *v9ses = sb->s_fs_info;
343 
344 	P9_DPRINTK(P9_DEBUG_VFS, "super block: %p mode: %o\n", sb, mode);
345 
346 	inode = new_inode(sb);
347 	if (!inode) {
348 		P9_EPRINTK(KERN_WARNING, "Problem allocating inode\n");
349 		return ERR_PTR(-ENOMEM);
350 	}
351 	err = v9fs_init_inode(v9ses, inode, mode);
352 	if (err) {
353 		iput(inode);
354 		return ERR_PTR(err);
355 	}
356 	return inode;
357 }
358 
359 /*
360 static struct v9fs_fid*
361 v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
362 {
363 	int err;
364 	int nfid;
365 	struct v9fs_fid *ret;
366 	struct v9fs_fcall *fcall;
367 
368 	nfid = v9fs_get_idpool(&v9ses->fidpool);
369 	if (nfid < 0) {
370 		eprintk(KERN_WARNING, "no free fids available\n");
371 		return ERR_PTR(-ENOSPC);
372 	}
373 
374 	err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
375 		&fcall);
376 
377 	if (err < 0) {
378 		if (fcall && fcall->id == RWALK)
379 			goto clunk_fid;
380 
381 		PRINT_FCALL_ERROR("walk error", fcall);
382 		v9fs_put_idpool(nfid, &v9ses->fidpool);
383 		goto error;
384 	}
385 
386 	kfree(fcall);
387 	fcall = NULL;
388 	ret = v9fs_fid_create(v9ses, nfid);
389 	if (!ret) {
390 		err = -ENOMEM;
391 		goto clunk_fid;
392 	}
393 
394 	err = v9fs_fid_insert(ret, dentry);
395 	if (err < 0) {
396 		v9fs_fid_destroy(ret);
397 		goto clunk_fid;
398 	}
399 
400 	return ret;
401 
402 clunk_fid:
403 	v9fs_t_clunk(v9ses, nfid);
404 
405 error:
406 	kfree(fcall);
407 	return ERR_PTR(err);
408 }
409 */
410 
411 
412 /**
413  * v9fs_clear_inode - release an inode
414  * @inode: inode to release
415  *
416  */
417 void v9fs_evict_inode(struct inode *inode)
418 {
419 	struct v9fs_inode *v9inode = V9FS_I(inode);
420 
421 	truncate_inode_pages(inode->i_mapping, 0);
422 	end_writeback(inode);
423 	filemap_fdatawrite(inode->i_mapping);
424 
425 #ifdef CONFIG_9P_FSCACHE
426 	v9fs_cache_inode_put_cookie(inode);
427 #endif
428 	/* clunk the fid stashed in writeback_fid */
429 	if (v9inode->writeback_fid) {
430 		p9_client_clunk(v9inode->writeback_fid);
431 		v9inode->writeback_fid = NULL;
432 	}
433 }
434 
435 static int v9fs_test_inode(struct inode *inode, void *data)
436 {
437 	int umode;
438 	struct v9fs_inode *v9inode = V9FS_I(inode);
439 	struct p9_wstat *st = (struct p9_wstat *)data;
440 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
441 
442 	umode = p9mode2unixmode(v9ses, st->mode);
443 	/* don't match inode of different type */
444 	if ((inode->i_mode & S_IFMT) != (umode & S_IFMT))
445 		return 0;
446 
447 	/* compare qid details */
448 	if (memcmp(&v9inode->qid.version,
449 		   &st->qid.version, sizeof(v9inode->qid.version)))
450 		return 0;
451 
452 	if (v9inode->qid.type != st->qid.type)
453 		return 0;
454 	return 1;
455 }
456 
457 static int v9fs_test_new_inode(struct inode *inode, void *data)
458 {
459 	return 0;
460 }
461 
462 static int v9fs_set_inode(struct inode *inode,  void *data)
463 {
464 	struct v9fs_inode *v9inode = V9FS_I(inode);
465 	struct p9_wstat *st = (struct p9_wstat *)data;
466 
467 	memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
468 	return 0;
469 }
470 
471 static struct inode *v9fs_qid_iget(struct super_block *sb,
472 				   struct p9_qid *qid,
473 				   struct p9_wstat *st,
474 				   int new)
475 {
476 	int retval, umode;
477 	unsigned long i_ino;
478 	struct inode *inode;
479 	struct v9fs_session_info *v9ses = sb->s_fs_info;
480 	int (*test)(struct inode *, void *);
481 
482 	if (new)
483 		test = v9fs_test_new_inode;
484 	else
485 		test = v9fs_test_inode;
486 
487 	i_ino = v9fs_qid2ino(qid);
488 	inode = iget5_locked(sb, i_ino, test, v9fs_set_inode, st);
489 	if (!inode)
490 		return ERR_PTR(-ENOMEM);
491 	if (!(inode->i_state & I_NEW))
492 		return inode;
493 	/*
494 	 * initialize the inode with the stat info
495 	 * FIXME!! we may need support for stale inodes
496 	 * later.
497 	 */
498 	inode->i_ino = i_ino;
499 	umode = p9mode2unixmode(v9ses, st->mode);
500 	retval = v9fs_init_inode(v9ses, inode, umode);
501 	if (retval)
502 		goto error;
503 
504 	v9fs_stat2inode(st, inode, sb);
505 #ifdef CONFIG_9P_FSCACHE
506 	v9fs_cache_inode_get_cookie(inode);
507 #endif
508 	unlock_new_inode(inode);
509 	return inode;
510 error:
511 	unlock_new_inode(inode);
512 	iput(inode);
513 	return ERR_PTR(retval);
514 
515 }
516 
517 struct inode *
518 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
519 		    struct super_block *sb, int new)
520 {
521 	struct p9_wstat *st;
522 	struct inode *inode = NULL;
523 
524 	st = p9_client_stat(fid);
525 	if (IS_ERR(st))
526 		return ERR_CAST(st);
527 
528 	inode = v9fs_qid_iget(sb, &st->qid, st, new);
529 	p9stat_free(st);
530 	kfree(st);
531 	return inode;
532 }
533 
534 /**
535  * v9fs_remove - helper function to remove files and directories
536  * @dir: directory inode that is being deleted
537  * @dentry:  dentry that is being deleted
538  * @rmdir: removing a directory
539  *
540  */
541 
542 static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
543 {
544 	struct inode *inode;
545 	int retval = -EOPNOTSUPP;
546 	struct p9_fid *v9fid, *dfid;
547 	struct v9fs_session_info *v9ses;
548 
549 	P9_DPRINTK(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
550 		   dir, dentry, flags);
551 
552 	v9ses = v9fs_inode2v9ses(dir);
553 	inode = dentry->d_inode;
554 	dfid = v9fs_fid_lookup(dentry->d_parent);
555 	if (IS_ERR(dfid)) {
556 		retval = PTR_ERR(dfid);
557 		P9_DPRINTK(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
558 		return retval;
559 	}
560 	if (v9fs_proto_dotl(v9ses))
561 		retval = p9_client_unlinkat(dfid, dentry->d_name.name, flags);
562 	if (retval == -EOPNOTSUPP) {
563 		/* Try the one based on path */
564 		v9fid = v9fs_fid_clone(dentry);
565 		if (IS_ERR(v9fid))
566 			return PTR_ERR(v9fid);
567 		retval = p9_client_remove(v9fid);
568 	}
569 	if (!retval) {
570 		/*
571 		 * directories on unlink should have zero
572 		 * link count
573 		 */
574 		if (flags & AT_REMOVEDIR) {
575 			clear_nlink(inode);
576 			drop_nlink(dir);
577 		} else
578 			drop_nlink(inode);
579 
580 		v9fs_invalidate_inode_attr(inode);
581 		v9fs_invalidate_inode_attr(dir);
582 	}
583 	return retval;
584 }
585 
586 /**
587  * v9fs_create - Create a file
588  * @v9ses: session information
589  * @dir: directory that dentry is being created in
590  * @dentry:  dentry that is being created
591  * @extension: 9p2000.u extension string to support devices, etc.
592  * @perm: create permissions
593  * @mode: open mode
594  *
595  */
596 static struct p9_fid *
597 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
598 		struct dentry *dentry, char *extension, u32 perm, u8 mode)
599 {
600 	int err;
601 	char *name;
602 	struct p9_fid *dfid, *ofid, *fid;
603 	struct inode *inode;
604 
605 	P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
606 
607 	err = 0;
608 	ofid = NULL;
609 	fid = NULL;
610 	name = (char *) dentry->d_name.name;
611 	dfid = v9fs_fid_lookup(dentry->d_parent);
612 	if (IS_ERR(dfid)) {
613 		err = PTR_ERR(dfid);
614 		P9_DPRINTK(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
615 		return ERR_PTR(err);
616 	}
617 
618 	/* clone a fid to use for creation */
619 	ofid = p9_client_walk(dfid, 0, NULL, 1);
620 	if (IS_ERR(ofid)) {
621 		err = PTR_ERR(ofid);
622 		P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
623 		return ERR_PTR(err);
624 	}
625 
626 	err = p9_client_fcreate(ofid, name, perm, mode, extension);
627 	if (err < 0) {
628 		P9_DPRINTK(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
629 		goto error;
630 	}
631 
632 	/* now walk from the parent so we can get unopened fid */
633 	fid = p9_client_walk(dfid, 1, &name, 1);
634 	if (IS_ERR(fid)) {
635 		err = PTR_ERR(fid);
636 		P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
637 		fid = NULL;
638 		goto error;
639 	}
640 
641 	/* instantiate inode and assign the unopened fid to the dentry */
642 	inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
643 	if (IS_ERR(inode)) {
644 		err = PTR_ERR(inode);
645 		P9_DPRINTK(P9_DEBUG_VFS, "inode creation failed %d\n", err);
646 		goto error;
647 	}
648 	d_instantiate(dentry, inode);
649 	err = v9fs_fid_add(dentry, fid);
650 	if (err < 0)
651 		goto error;
652 
653 	return ofid;
654 
655 error:
656 	if (ofid)
657 		p9_client_clunk(ofid);
658 
659 	if (fid)
660 		p9_client_clunk(fid);
661 
662 	return ERR_PTR(err);
663 }
664 
665 /**
666  * v9fs_vfs_create - VFS hook to create files
667  * @dir: directory inode that is being created
668  * @dentry:  dentry that is being deleted
669  * @mode: create permissions
670  * @nd: path information
671  *
672  */
673 
674 static int
675 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
676 		struct nameidata *nd)
677 {
678 	int err;
679 	u32 perm;
680 	int flags;
681 	struct file *filp;
682 	struct v9fs_inode *v9inode;
683 	struct v9fs_session_info *v9ses;
684 	struct p9_fid *fid, *inode_fid;
685 
686 	err = 0;
687 	fid = NULL;
688 	v9ses = v9fs_inode2v9ses(dir);
689 	perm = unixmode2p9mode(v9ses, mode);
690 	if (nd)
691 		flags = nd->intent.open.flags;
692 	else
693 		flags = O_RDWR;
694 
695 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
696 				v9fs_uflags2omode(flags,
697 						v9fs_proto_dotu(v9ses)));
698 	if (IS_ERR(fid)) {
699 		err = PTR_ERR(fid);
700 		fid = NULL;
701 		goto error;
702 	}
703 
704 	v9fs_invalidate_inode_attr(dir);
705 	/* if we are opening a file, assign the open fid to the file */
706 	if (nd) {
707 		v9inode = V9FS_I(dentry->d_inode);
708 		mutex_lock(&v9inode->v_mutex);
709 		if (v9ses->cache && !v9inode->writeback_fid &&
710 		    ((flags & O_ACCMODE) != O_RDONLY)) {
711 			/*
712 			 * clone a fid and add it to writeback_fid
713 			 * we do it during open time instead of
714 			 * page dirty time via write_begin/page_mkwrite
715 			 * because we want write after unlink usecase
716 			 * to work.
717 			 */
718 			inode_fid = v9fs_writeback_fid(dentry);
719 			if (IS_ERR(inode_fid)) {
720 				err = PTR_ERR(inode_fid);
721 				mutex_unlock(&v9inode->v_mutex);
722 				goto error;
723 			}
724 			v9inode->writeback_fid = (void *) inode_fid;
725 		}
726 		mutex_unlock(&v9inode->v_mutex);
727 		filp = lookup_instantiate_filp(nd, dentry, generic_file_open);
728 		if (IS_ERR(filp)) {
729 			err = PTR_ERR(filp);
730 			goto error;
731 		}
732 
733 		filp->private_data = fid;
734 #ifdef CONFIG_9P_FSCACHE
735 		if (v9ses->cache)
736 			v9fs_cache_inode_set_cookie(dentry->d_inode, filp);
737 #endif
738 	} else
739 		p9_client_clunk(fid);
740 
741 	return 0;
742 
743 error:
744 	if (fid)
745 		p9_client_clunk(fid);
746 
747 	return err;
748 }
749 
750 /**
751  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
752  * @dir:  inode that is being unlinked
753  * @dentry: dentry that is being unlinked
754  * @mode: mode for new directory
755  *
756  */
757 
758 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
759 {
760 	int err;
761 	u32 perm;
762 	struct p9_fid *fid;
763 	struct v9fs_session_info *v9ses;
764 
765 	P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
766 	err = 0;
767 	v9ses = v9fs_inode2v9ses(dir);
768 	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
769 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
770 	if (IS_ERR(fid)) {
771 		err = PTR_ERR(fid);
772 		fid = NULL;
773 	} else {
774 		inc_nlink(dir);
775 		v9fs_invalidate_inode_attr(dir);
776 	}
777 
778 	if (fid)
779 		p9_client_clunk(fid);
780 
781 	return err;
782 }
783 
784 /**
785  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
786  * @dir:  inode that is being walked from
787  * @dentry: dentry that is being walked to?
788  * @nameidata: path data
789  *
790  */
791 
792 struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
793 				      struct nameidata *nameidata)
794 {
795 	struct super_block *sb;
796 	struct v9fs_session_info *v9ses;
797 	struct p9_fid *dfid, *fid;
798 	struct inode *inode;
799 	char *name;
800 	int result = 0;
801 
802 	P9_DPRINTK(P9_DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
803 		dir, dentry->d_name.name, dentry, nameidata);
804 
805 	if (dentry->d_name.len > NAME_MAX)
806 		return ERR_PTR(-ENAMETOOLONG);
807 
808 	sb = dir->i_sb;
809 	v9ses = v9fs_inode2v9ses(dir);
810 	/* We can walk d_parent because we hold the dir->i_mutex */
811 	dfid = v9fs_fid_lookup(dentry->d_parent);
812 	if (IS_ERR(dfid))
813 		return ERR_CAST(dfid);
814 
815 	name = (char *) dentry->d_name.name;
816 	fid = p9_client_walk(dfid, 1, &name, 1);
817 	if (IS_ERR(fid)) {
818 		result = PTR_ERR(fid);
819 		if (result == -ENOENT) {
820 			inode = NULL;
821 			goto inst_out;
822 		}
823 
824 		return ERR_PTR(result);
825 	}
826 
827 	inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
828 	if (IS_ERR(inode)) {
829 		result = PTR_ERR(inode);
830 		inode = NULL;
831 		goto error;
832 	}
833 
834 	result = v9fs_fid_add(dentry, fid);
835 	if (result < 0)
836 		goto error_iput;
837 
838 inst_out:
839 	d_add(dentry, inode);
840 	return NULL;
841 
842 error_iput:
843 	iput(inode);
844 error:
845 	p9_client_clunk(fid);
846 
847 	return ERR_PTR(result);
848 }
849 
850 /**
851  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
852  * @i:  inode that is being unlinked
853  * @d: dentry that is being unlinked
854  *
855  */
856 
857 int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
858 {
859 	return v9fs_remove(i, d, 0);
860 }
861 
862 /**
863  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
864  * @i:  inode that is being unlinked
865  * @d: dentry that is being unlinked
866  *
867  */
868 
869 int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
870 {
871 	return v9fs_remove(i, d, AT_REMOVEDIR);
872 }
873 
874 /**
875  * v9fs_vfs_rename - VFS hook to rename an inode
876  * @old_dir:  old dir inode
877  * @old_dentry: old dentry
878  * @new_dir: new dir inode
879  * @new_dentry: new dentry
880  *
881  */
882 
883 int
884 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
885 		struct inode *new_dir, struct dentry *new_dentry)
886 {
887 	int retval;
888 	struct inode *old_inode;
889 	struct inode *new_inode;
890 	struct v9fs_session_info *v9ses;
891 	struct p9_fid *oldfid;
892 	struct p9_fid *olddirfid;
893 	struct p9_fid *newdirfid;
894 	struct p9_wstat wstat;
895 
896 	P9_DPRINTK(P9_DEBUG_VFS, "\n");
897 	retval = 0;
898 	old_inode = old_dentry->d_inode;
899 	new_inode = new_dentry->d_inode;
900 	v9ses = v9fs_inode2v9ses(old_inode);
901 	oldfid = v9fs_fid_lookup(old_dentry);
902 	if (IS_ERR(oldfid))
903 		return PTR_ERR(oldfid);
904 
905 	olddirfid = v9fs_fid_clone(old_dentry->d_parent);
906 	if (IS_ERR(olddirfid)) {
907 		retval = PTR_ERR(olddirfid);
908 		goto done;
909 	}
910 
911 	newdirfid = v9fs_fid_clone(new_dentry->d_parent);
912 	if (IS_ERR(newdirfid)) {
913 		retval = PTR_ERR(newdirfid);
914 		goto clunk_olddir;
915 	}
916 
917 	down_write(&v9ses->rename_sem);
918 	if (v9fs_proto_dotl(v9ses)) {
919 		retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
920 					    newdirfid, new_dentry->d_name.name);
921 		if (retval == -EOPNOTSUPP)
922 			retval = p9_client_rename(oldfid, newdirfid,
923 						  new_dentry->d_name.name);
924 		if (retval != -EOPNOTSUPP)
925 			goto clunk_newdir;
926 	}
927 	if (old_dentry->d_parent != new_dentry->d_parent) {
928 		/*
929 		 * 9P .u can only handle file rename in the same directory
930 		 */
931 
932 		P9_DPRINTK(P9_DEBUG_ERROR,
933 				"old dir and new dir are different\n");
934 		retval = -EXDEV;
935 		goto clunk_newdir;
936 	}
937 	v9fs_blank_wstat(&wstat);
938 	wstat.muid = v9ses->uname;
939 	wstat.name = (char *) new_dentry->d_name.name;
940 	retval = p9_client_wstat(oldfid, &wstat);
941 
942 clunk_newdir:
943 	if (!retval) {
944 		if (new_inode) {
945 			if (S_ISDIR(new_inode->i_mode))
946 				clear_nlink(new_inode);
947 			else
948 				drop_nlink(new_inode);
949 		}
950 		if (S_ISDIR(old_inode->i_mode)) {
951 			if (!new_inode)
952 				inc_nlink(new_dir);
953 			drop_nlink(old_dir);
954 		}
955 		v9fs_invalidate_inode_attr(old_inode);
956 		v9fs_invalidate_inode_attr(old_dir);
957 		v9fs_invalidate_inode_attr(new_dir);
958 
959 		/* successful rename */
960 		d_move(old_dentry, new_dentry);
961 	}
962 	up_write(&v9ses->rename_sem);
963 	p9_client_clunk(newdirfid);
964 
965 clunk_olddir:
966 	p9_client_clunk(olddirfid);
967 
968 done:
969 	return retval;
970 }
971 
972 /**
973  * v9fs_vfs_getattr - retrieve file metadata
974  * @mnt: mount information
975  * @dentry: file to get attributes on
976  * @stat: metadata structure to populate
977  *
978  */
979 
980 static int
981 v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
982 		 struct kstat *stat)
983 {
984 	int err;
985 	struct v9fs_session_info *v9ses;
986 	struct p9_fid *fid;
987 	struct p9_wstat *st;
988 
989 	P9_DPRINTK(P9_DEBUG_VFS, "dentry: %p\n", dentry);
990 	err = -EPERM;
991 	v9ses = v9fs_dentry2v9ses(dentry);
992 	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
993 		generic_fillattr(dentry->d_inode, stat);
994 		return 0;
995 	}
996 	fid = v9fs_fid_lookup(dentry);
997 	if (IS_ERR(fid))
998 		return PTR_ERR(fid);
999 
1000 	st = p9_client_stat(fid);
1001 	if (IS_ERR(st))
1002 		return PTR_ERR(st);
1003 
1004 	v9fs_stat2inode(st, dentry->d_inode, dentry->d_inode->i_sb);
1005 		generic_fillattr(dentry->d_inode, stat);
1006 
1007 	p9stat_free(st);
1008 	kfree(st);
1009 	return 0;
1010 }
1011 
1012 /**
1013  * v9fs_vfs_setattr - set file metadata
1014  * @dentry: file whose metadata to set
1015  * @iattr: metadata assignment structure
1016  *
1017  */
1018 
1019 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
1020 {
1021 	int retval;
1022 	struct v9fs_session_info *v9ses;
1023 	struct p9_fid *fid;
1024 	struct p9_wstat wstat;
1025 
1026 	P9_DPRINTK(P9_DEBUG_VFS, "\n");
1027 	retval = inode_change_ok(dentry->d_inode, iattr);
1028 	if (retval)
1029 		return retval;
1030 
1031 	retval = -EPERM;
1032 	v9ses = v9fs_dentry2v9ses(dentry);
1033 	fid = v9fs_fid_lookup(dentry);
1034 	if(IS_ERR(fid))
1035 		return PTR_ERR(fid);
1036 
1037 	v9fs_blank_wstat(&wstat);
1038 	if (iattr->ia_valid & ATTR_MODE)
1039 		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
1040 
1041 	if (iattr->ia_valid & ATTR_MTIME)
1042 		wstat.mtime = iattr->ia_mtime.tv_sec;
1043 
1044 	if (iattr->ia_valid & ATTR_ATIME)
1045 		wstat.atime = iattr->ia_atime.tv_sec;
1046 
1047 	if (iattr->ia_valid & ATTR_SIZE)
1048 		wstat.length = iattr->ia_size;
1049 
1050 	if (v9fs_proto_dotu(v9ses)) {
1051 		if (iattr->ia_valid & ATTR_UID)
1052 			wstat.n_uid = iattr->ia_uid;
1053 
1054 		if (iattr->ia_valid & ATTR_GID)
1055 			wstat.n_gid = iattr->ia_gid;
1056 	}
1057 
1058 	/* Write all dirty data */
1059 	if (S_ISREG(dentry->d_inode->i_mode))
1060 		filemap_write_and_wait(dentry->d_inode->i_mapping);
1061 
1062 	retval = p9_client_wstat(fid, &wstat);
1063 	if (retval < 0)
1064 		return retval;
1065 
1066 	if ((iattr->ia_valid & ATTR_SIZE) &&
1067 	    iattr->ia_size != i_size_read(dentry->d_inode))
1068 		truncate_setsize(dentry->d_inode, iattr->ia_size);
1069 
1070 	v9fs_invalidate_inode_attr(dentry->d_inode);
1071 
1072 	setattr_copy(dentry->d_inode, iattr);
1073 	mark_inode_dirty(dentry->d_inode);
1074 	return 0;
1075 }
1076 
1077 /**
1078  * v9fs_stat2inode - populate an inode structure with mistat info
1079  * @stat: Plan 9 metadata (mistat) structure
1080  * @inode: inode to populate
1081  * @sb: superblock of filesystem
1082  *
1083  */
1084 
1085 void
1086 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
1087 	struct super_block *sb)
1088 {
1089 	char ext[32];
1090 	char tag_name[14];
1091 	unsigned int i_nlink;
1092 	struct v9fs_session_info *v9ses = sb->s_fs_info;
1093 	struct v9fs_inode *v9inode = V9FS_I(inode);
1094 
1095 	inode->i_nlink = 1;
1096 
1097 	inode->i_atime.tv_sec = stat->atime;
1098 	inode->i_mtime.tv_sec = stat->mtime;
1099 	inode->i_ctime.tv_sec = stat->mtime;
1100 
1101 	inode->i_uid = v9ses->dfltuid;
1102 	inode->i_gid = v9ses->dfltgid;
1103 
1104 	if (v9fs_proto_dotu(v9ses)) {
1105 		inode->i_uid = stat->n_uid;
1106 		inode->i_gid = stat->n_gid;
1107 	}
1108 	if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
1109 		if (v9fs_proto_dotu(v9ses) && (stat->extension[0] != '\0')) {
1110 			/*
1111 			 * Hadlink support got added later to
1112 			 * to the .u extension. So there can be
1113 			 * server out there that doesn't support
1114 			 * this even with .u extension. So check
1115 			 * for non NULL stat->extension
1116 			 */
1117 			strncpy(ext, stat->extension, sizeof(ext));
1118 			/* HARDLINKCOUNT %u */
1119 			sscanf(ext, "%13s %u", tag_name, &i_nlink);
1120 			if (!strncmp(tag_name, "HARDLINKCOUNT", 13))
1121 				inode->i_nlink = i_nlink;
1122 		}
1123 	}
1124 	inode->i_mode = p9mode2unixmode(v9ses, stat->mode);
1125 	if ((S_ISBLK(inode->i_mode)) || (S_ISCHR(inode->i_mode))) {
1126 		char type = 0;
1127 		int major = -1;
1128 		int minor = -1;
1129 
1130 		strncpy(ext, stat->extension, sizeof(ext));
1131 		sscanf(ext, "%c %u %u", &type, &major, &minor);
1132 		switch (type) {
1133 		case 'c':
1134 			inode->i_mode &= ~S_IFBLK;
1135 			inode->i_mode |= S_IFCHR;
1136 			break;
1137 		case 'b':
1138 			break;
1139 		default:
1140 			P9_DPRINTK(P9_DEBUG_ERROR,
1141 				"Unknown special type %c %s\n", type,
1142 				stat->extension);
1143 		};
1144 		inode->i_rdev = MKDEV(major, minor);
1145 		init_special_inode(inode, inode->i_mode, inode->i_rdev);
1146 	} else
1147 		inode->i_rdev = 0;
1148 
1149 	i_size_write(inode, stat->length);
1150 
1151 	/* not real number of blocks, but 512 byte ones ... */
1152 	inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
1153 	v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
1154 }
1155 
1156 /**
1157  * v9fs_qid2ino - convert qid into inode number
1158  * @qid: qid to hash
1159  *
1160  * BUG: potential for inode number collisions?
1161  */
1162 
1163 ino_t v9fs_qid2ino(struct p9_qid *qid)
1164 {
1165 	u64 path = qid->path + 2;
1166 	ino_t i = 0;
1167 
1168 	if (sizeof(ino_t) == sizeof(path))
1169 		memcpy(&i, &path, sizeof(ino_t));
1170 	else
1171 		i = (ino_t) (path ^ (path >> 32));
1172 
1173 	return i;
1174 }
1175 
1176 /**
1177  * v9fs_readlink - read a symlink's location (internal version)
1178  * @dentry: dentry for symlink
1179  * @buffer: buffer to load symlink location into
1180  * @buflen: length of buffer
1181  *
1182  */
1183 
1184 static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
1185 {
1186 	int retval;
1187 
1188 	struct v9fs_session_info *v9ses;
1189 	struct p9_fid *fid;
1190 	struct p9_wstat *st;
1191 
1192 	P9_DPRINTK(P9_DEBUG_VFS, " %s\n", dentry->d_name.name);
1193 	retval = -EPERM;
1194 	v9ses = v9fs_dentry2v9ses(dentry);
1195 	fid = v9fs_fid_lookup(dentry);
1196 	if (IS_ERR(fid))
1197 		return PTR_ERR(fid);
1198 
1199 	if (!v9fs_proto_dotu(v9ses))
1200 		return -EBADF;
1201 
1202 	st = p9_client_stat(fid);
1203 	if (IS_ERR(st))
1204 		return PTR_ERR(st);
1205 
1206 	if (!(st->mode & P9_DMSYMLINK)) {
1207 		retval = -EINVAL;
1208 		goto done;
1209 	}
1210 
1211 	/* copy extension buffer into buffer */
1212 	strncpy(buffer, st->extension, buflen);
1213 
1214 	P9_DPRINTK(P9_DEBUG_VFS,
1215 		"%s -> %s (%s)\n", dentry->d_name.name, st->extension, buffer);
1216 
1217 	retval = strnlen(buffer, buflen);
1218 done:
1219 	p9stat_free(st);
1220 	kfree(st);
1221 	return retval;
1222 }
1223 
1224 /**
1225  * v9fs_vfs_follow_link - follow a symlink path
1226  * @dentry: dentry for symlink
1227  * @nd: nameidata
1228  *
1229  */
1230 
1231 static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
1232 {
1233 	int len = 0;
1234 	char *link = __getname();
1235 
1236 	P9_DPRINTK(P9_DEBUG_VFS, "%s n", dentry->d_name.name);
1237 
1238 	if (!link)
1239 		link = ERR_PTR(-ENOMEM);
1240 	else {
1241 		len = v9fs_readlink(dentry, link, PATH_MAX);
1242 
1243 		if (len < 0) {
1244 			__putname(link);
1245 			link = ERR_PTR(len);
1246 		} else
1247 			link[min(len, PATH_MAX-1)] = 0;
1248 	}
1249 	nd_set_link(nd, link);
1250 
1251 	return NULL;
1252 }
1253 
1254 /**
1255  * v9fs_vfs_put_link - release a symlink path
1256  * @dentry: dentry for symlink
1257  * @nd: nameidata
1258  * @p: unused
1259  *
1260  */
1261 
1262 void
1263 v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
1264 {
1265 	char *s = nd_get_link(nd);
1266 
1267 	P9_DPRINTK(P9_DEBUG_VFS, " %s %s\n", dentry->d_name.name,
1268 		IS_ERR(s) ? "<error>" : s);
1269 	if (!IS_ERR(s))
1270 		__putname(s);
1271 }
1272 
1273 /**
1274  * v9fs_vfs_mkspecial - create a special file
1275  * @dir: inode to create special file in
1276  * @dentry: dentry to create
1277  * @mode: mode to create special file
1278  * @extension: 9p2000.u format extension string representing special file
1279  *
1280  */
1281 
1282 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1283 	int mode, const char *extension)
1284 {
1285 	u32 perm;
1286 	struct p9_fid *fid;
1287 	struct v9fs_session_info *v9ses;
1288 
1289 	v9ses = v9fs_inode2v9ses(dir);
1290 	if (!v9fs_proto_dotu(v9ses)) {
1291 		P9_DPRINTK(P9_DEBUG_ERROR, "not extended\n");
1292 		return -EPERM;
1293 	}
1294 
1295 	perm = unixmode2p9mode(v9ses, mode);
1296 	fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1297 								P9_OREAD);
1298 	if (IS_ERR(fid))
1299 		return PTR_ERR(fid);
1300 
1301 	v9fs_invalidate_inode_attr(dir);
1302 	p9_client_clunk(fid);
1303 	return 0;
1304 }
1305 
1306 /**
1307  * v9fs_vfs_symlink - helper function to create symlinks
1308  * @dir: directory inode containing symlink
1309  * @dentry: dentry for symlink
1310  * @symname: symlink data
1311  *
1312  * See Also: 9P2000.u RFC for more information
1313  *
1314  */
1315 
1316 static int
1317 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1318 {
1319 	P9_DPRINTK(P9_DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino,
1320 					dentry->d_name.name, symname);
1321 
1322 	return v9fs_vfs_mkspecial(dir, dentry, S_IFLNK, symname);
1323 }
1324 
1325 /**
1326  * v9fs_vfs_link - create a hardlink
1327  * @old_dentry: dentry for file to link to
1328  * @dir: inode destination for new link
1329  * @dentry: dentry for link
1330  *
1331  */
1332 
1333 static int
1334 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1335 	      struct dentry *dentry)
1336 {
1337 	int retval;
1338 	char *name;
1339 	struct p9_fid *oldfid;
1340 
1341 	P9_DPRINTK(P9_DEBUG_VFS,
1342 		" %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
1343 		old_dentry->d_name.name);
1344 
1345 	oldfid = v9fs_fid_clone(old_dentry);
1346 	if (IS_ERR(oldfid))
1347 		return PTR_ERR(oldfid);
1348 
1349 	name = __getname();
1350 	if (unlikely(!name)) {
1351 		retval = -ENOMEM;
1352 		goto clunk_fid;
1353 	}
1354 
1355 	sprintf(name, "%d\n", oldfid->fid);
1356 	retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1357 	__putname(name);
1358 	if (!retval) {
1359 		v9fs_refresh_inode(oldfid, old_dentry->d_inode);
1360 		v9fs_invalidate_inode_attr(dir);
1361 	}
1362 clunk_fid:
1363 	p9_client_clunk(oldfid);
1364 	return retval;
1365 }
1366 
1367 /**
1368  * v9fs_vfs_mknod - create a special file
1369  * @dir: inode destination for new link
1370  * @dentry: dentry for file
1371  * @mode: mode for creation
1372  * @rdev: device associated with special file
1373  *
1374  */
1375 
1376 static int
1377 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
1378 {
1379 	int retval;
1380 	char *name;
1381 
1382 	P9_DPRINTK(P9_DEBUG_VFS,
1383 		" %lu,%s mode: %x MAJOR: %u MINOR: %u\n", dir->i_ino,
1384 		dentry->d_name.name, mode, MAJOR(rdev), MINOR(rdev));
1385 
1386 	if (!new_valid_dev(rdev))
1387 		return -EINVAL;
1388 
1389 	name = __getname();
1390 	if (!name)
1391 		return -ENOMEM;
1392 	/* build extension */
1393 	if (S_ISBLK(mode))
1394 		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1395 	else if (S_ISCHR(mode))
1396 		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1397 	else if (S_ISFIFO(mode))
1398 		*name = 0;
1399 	else if (S_ISSOCK(mode))
1400 		*name = 0;
1401 	else {
1402 		__putname(name);
1403 		return -EINVAL;
1404 	}
1405 
1406 	retval = v9fs_vfs_mkspecial(dir, dentry, mode, name);
1407 	__putname(name);
1408 
1409 	return retval;
1410 }
1411 
1412 int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
1413 {
1414 	loff_t i_size;
1415 	struct p9_wstat *st;
1416 	struct v9fs_session_info *v9ses;
1417 
1418 	v9ses = v9fs_inode2v9ses(inode);
1419 	st = p9_client_stat(fid);
1420 	if (IS_ERR(st))
1421 		return PTR_ERR(st);
1422 
1423 	spin_lock(&inode->i_lock);
1424 	/*
1425 	 * We don't want to refresh inode->i_size,
1426 	 * because we may have cached data
1427 	 */
1428 	i_size = inode->i_size;
1429 	v9fs_stat2inode(st, inode, inode->i_sb);
1430 	if (v9ses->cache)
1431 		inode->i_size = i_size;
1432 	spin_unlock(&inode->i_lock);
1433 	p9stat_free(st);
1434 	kfree(st);
1435 	return 0;
1436 }
1437 
1438 static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1439 	.create = v9fs_vfs_create,
1440 	.lookup = v9fs_vfs_lookup,
1441 	.symlink = v9fs_vfs_symlink,
1442 	.link = v9fs_vfs_link,
1443 	.unlink = v9fs_vfs_unlink,
1444 	.mkdir = v9fs_vfs_mkdir,
1445 	.rmdir = v9fs_vfs_rmdir,
1446 	.mknod = v9fs_vfs_mknod,
1447 	.rename = v9fs_vfs_rename,
1448 	.getattr = v9fs_vfs_getattr,
1449 	.setattr = v9fs_vfs_setattr,
1450 };
1451 
1452 static const struct inode_operations v9fs_dir_inode_operations = {
1453 	.create = v9fs_vfs_create,
1454 	.lookup = v9fs_vfs_lookup,
1455 	.unlink = v9fs_vfs_unlink,
1456 	.mkdir = v9fs_vfs_mkdir,
1457 	.rmdir = v9fs_vfs_rmdir,
1458 	.mknod = v9fs_vfs_mknod,
1459 	.rename = v9fs_vfs_rename,
1460 	.getattr = v9fs_vfs_getattr,
1461 	.setattr = v9fs_vfs_setattr,
1462 };
1463 
1464 static const struct inode_operations v9fs_file_inode_operations = {
1465 	.getattr = v9fs_vfs_getattr,
1466 	.setattr = v9fs_vfs_setattr,
1467 };
1468 
1469 static const struct inode_operations v9fs_symlink_inode_operations = {
1470 	.readlink = generic_readlink,
1471 	.follow_link = v9fs_vfs_follow_link,
1472 	.put_link = v9fs_vfs_put_link,
1473 	.getattr = v9fs_vfs_getattr,
1474 	.setattr = v9fs_vfs_setattr,
1475 };
1476 
1477