xref: /linux/fs/9p/vfs_inode.c (revision cff4fa8415a3224a5abdd2b1dd7f431e4ea49366)
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  * @stat: p9_wstat from which mode need to be derived
99  * @rdev: major number, minor number in case of device files.
100  *
101  */
102 static int p9mode2unixmode(struct v9fs_session_info *v9ses,
103 			   struct p9_wstat *stat, dev_t *rdev)
104 {
105 	int res;
106 	int mode = stat->mode;
107 
108 	res = mode & S_IALLUGO;
109 	*rdev = 0;
110 
111 	if ((mode & P9_DMDIR) == P9_DMDIR)
112 		res |= S_IFDIR;
113 	else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
114 		res |= S_IFLNK;
115 	else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
116 		 && (v9ses->nodev == 0))
117 		res |= S_IFSOCK;
118 	else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
119 		 && (v9ses->nodev == 0))
120 		res |= S_IFIFO;
121 	else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
122 		 && (v9ses->nodev == 0)) {
123 		char type = 0, ext[32];
124 		int major = -1, minor = -1;
125 
126 		strncpy(ext, stat->extension, sizeof(ext));
127 		sscanf(ext, "%c %u %u", &type, &major, &minor);
128 		switch (type) {
129 		case 'c':
130 			res |= S_IFCHR;
131 			break;
132 		case 'b':
133 			res |= S_IFBLK;
134 			break;
135 		default:
136 			P9_DPRINTK(P9_DEBUG_ERROR,
137 				"Unknown special type %c %s\n", type,
138 				stat->extension);
139 		};
140 		*rdev = MKDEV(major, minor);
141 	} else
142 		res |= S_IFREG;
143 
144 	if (v9fs_proto_dotu(v9ses)) {
145 		if ((mode & P9_DMSETUID) == P9_DMSETUID)
146 			res |= S_ISUID;
147 
148 		if ((mode & P9_DMSETGID) == P9_DMSETGID)
149 			res |= S_ISGID;
150 
151 		if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
152 			res |= S_ISVTX;
153 	}
154 	return res;
155 }
156 
157 /**
158  * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
159  * @uflags: flags to convert
160  * @extended: if .u extensions are active
161  */
162 
163 int v9fs_uflags2omode(int uflags, int extended)
164 {
165 	int ret;
166 
167 	ret = 0;
168 	switch (uflags&3) {
169 	default:
170 	case O_RDONLY:
171 		ret = P9_OREAD;
172 		break;
173 
174 	case O_WRONLY:
175 		ret = P9_OWRITE;
176 		break;
177 
178 	case O_RDWR:
179 		ret = P9_ORDWR;
180 		break;
181 	}
182 
183 	if (uflags & O_TRUNC)
184 		ret |= P9_OTRUNC;
185 
186 	if (extended) {
187 		if (uflags & O_EXCL)
188 			ret |= P9_OEXCL;
189 
190 		if (uflags & O_APPEND)
191 			ret |= P9_OAPPEND;
192 	}
193 
194 	return ret;
195 }
196 
197 /**
198  * v9fs_blank_wstat - helper function to setup a 9P stat structure
199  * @wstat: structure to initialize
200  *
201  */
202 
203 void
204 v9fs_blank_wstat(struct p9_wstat *wstat)
205 {
206 	wstat->type = ~0;
207 	wstat->dev = ~0;
208 	wstat->qid.type = ~0;
209 	wstat->qid.version = ~0;
210 	*((long long *)&wstat->qid.path) = ~0;
211 	wstat->mode = ~0;
212 	wstat->atime = ~0;
213 	wstat->mtime = ~0;
214 	wstat->length = ~0;
215 	wstat->name = NULL;
216 	wstat->uid = NULL;
217 	wstat->gid = NULL;
218 	wstat->muid = NULL;
219 	wstat->n_uid = ~0;
220 	wstat->n_gid = ~0;
221 	wstat->n_muid = ~0;
222 	wstat->extension = NULL;
223 }
224 
225 /**
226  * v9fs_alloc_inode - helper function to allocate an inode
227  *
228  */
229 struct inode *v9fs_alloc_inode(struct super_block *sb)
230 {
231 	struct v9fs_inode *v9inode;
232 	v9inode = (struct v9fs_inode *)kmem_cache_alloc(v9fs_inode_cache,
233 							GFP_KERNEL);
234 	if (!v9inode)
235 		return NULL;
236 #ifdef CONFIG_9P_FSCACHE
237 	v9inode->fscache = NULL;
238 	spin_lock_init(&v9inode->fscache_lock);
239 #endif
240 	v9inode->writeback_fid = NULL;
241 	v9inode->cache_validity = 0;
242 	mutex_init(&v9inode->v_mutex);
243 	return &v9inode->vfs_inode;
244 }
245 
246 /**
247  * v9fs_destroy_inode - destroy an inode
248  *
249  */
250 
251 static void v9fs_i_callback(struct rcu_head *head)
252 {
253 	struct inode *inode = container_of(head, struct inode, i_rcu);
254 	INIT_LIST_HEAD(&inode->i_dentry);
255 	kmem_cache_free(v9fs_inode_cache, V9FS_I(inode));
256 }
257 
258 void v9fs_destroy_inode(struct inode *inode)
259 {
260 	call_rcu(&inode->i_rcu, v9fs_i_callback);
261 }
262 
263 int v9fs_init_inode(struct v9fs_session_info *v9ses,
264 		    struct inode *inode, int mode, dev_t rdev)
265 {
266 	int err = 0;
267 
268 	inode_init_owner(inode, NULL, mode);
269 	inode->i_blocks = 0;
270 	inode->i_rdev = rdev;
271 	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
272 	inode->i_mapping->a_ops = &v9fs_addr_operations;
273 
274 	switch (mode & S_IFMT) {
275 	case S_IFIFO:
276 	case S_IFBLK:
277 	case S_IFCHR:
278 	case S_IFSOCK:
279 		if (v9fs_proto_dotl(v9ses)) {
280 			inode->i_op = &v9fs_file_inode_operations_dotl;
281 			inode->i_fop = &v9fs_file_operations_dotl;
282 		} else if (v9fs_proto_dotu(v9ses)) {
283 			inode->i_op = &v9fs_file_inode_operations;
284 			inode->i_fop = &v9fs_file_operations;
285 		} else {
286 			P9_DPRINTK(P9_DEBUG_ERROR,
287 				   "special files without extended mode\n");
288 			err = -EINVAL;
289 			goto error;
290 		}
291 		init_special_inode(inode, inode->i_mode, inode->i_rdev);
292 		break;
293 	case S_IFREG:
294 		if (v9fs_proto_dotl(v9ses)) {
295 			inode->i_op = &v9fs_file_inode_operations_dotl;
296 			if (v9ses->cache)
297 				inode->i_fop =
298 					&v9fs_cached_file_operations_dotl;
299 			else
300 				inode->i_fop = &v9fs_file_operations_dotl;
301 		} else {
302 			inode->i_op = &v9fs_file_inode_operations;
303 			if (v9ses->cache)
304 				inode->i_fop = &v9fs_cached_file_operations;
305 			else
306 				inode->i_fop = &v9fs_file_operations;
307 		}
308 
309 		break;
310 	case S_IFLNK:
311 		if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
312 			P9_DPRINTK(P9_DEBUG_ERROR, "extended modes used with "
313 						"legacy protocol.\n");
314 			err = -EINVAL;
315 			goto error;
316 		}
317 
318 		if (v9fs_proto_dotl(v9ses))
319 			inode->i_op = &v9fs_symlink_inode_operations_dotl;
320 		else
321 			inode->i_op = &v9fs_symlink_inode_operations;
322 
323 		break;
324 	case S_IFDIR:
325 		inc_nlink(inode);
326 		if (v9fs_proto_dotl(v9ses))
327 			inode->i_op = &v9fs_dir_inode_operations_dotl;
328 		else if (v9fs_proto_dotu(v9ses))
329 			inode->i_op = &v9fs_dir_inode_operations_dotu;
330 		else
331 			inode->i_op = &v9fs_dir_inode_operations;
332 
333 		if (v9fs_proto_dotl(v9ses))
334 			inode->i_fop = &v9fs_dir_operations_dotl;
335 		else
336 			inode->i_fop = &v9fs_dir_operations;
337 
338 		break;
339 	default:
340 		P9_DPRINTK(P9_DEBUG_ERROR, "BAD mode 0x%x S_IFMT 0x%x\n",
341 			   mode, mode & S_IFMT);
342 		err = -EINVAL;
343 		goto error;
344 	}
345 error:
346 	return err;
347 
348 }
349 
350 /**
351  * v9fs_get_inode - helper function to setup an inode
352  * @sb: superblock
353  * @mode: mode to setup inode with
354  *
355  */
356 
357 struct inode *v9fs_get_inode(struct super_block *sb, int mode, dev_t rdev)
358 {
359 	int err;
360 	struct inode *inode;
361 	struct v9fs_session_info *v9ses = sb->s_fs_info;
362 
363 	P9_DPRINTK(P9_DEBUG_VFS, "super block: %p mode: %o\n", sb, mode);
364 
365 	inode = new_inode(sb);
366 	if (!inode) {
367 		P9_EPRINTK(KERN_WARNING, "Problem allocating inode\n");
368 		return ERR_PTR(-ENOMEM);
369 	}
370 	err = v9fs_init_inode(v9ses, inode, mode, rdev);
371 	if (err) {
372 		iput(inode);
373 		return ERR_PTR(err);
374 	}
375 	return inode;
376 }
377 
378 /*
379 static struct v9fs_fid*
380 v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
381 {
382 	int err;
383 	int nfid;
384 	struct v9fs_fid *ret;
385 	struct v9fs_fcall *fcall;
386 
387 	nfid = v9fs_get_idpool(&v9ses->fidpool);
388 	if (nfid < 0) {
389 		eprintk(KERN_WARNING, "no free fids available\n");
390 		return ERR_PTR(-ENOSPC);
391 	}
392 
393 	err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
394 		&fcall);
395 
396 	if (err < 0) {
397 		if (fcall && fcall->id == RWALK)
398 			goto clunk_fid;
399 
400 		PRINT_FCALL_ERROR("walk error", fcall);
401 		v9fs_put_idpool(nfid, &v9ses->fidpool);
402 		goto error;
403 	}
404 
405 	kfree(fcall);
406 	fcall = NULL;
407 	ret = v9fs_fid_create(v9ses, nfid);
408 	if (!ret) {
409 		err = -ENOMEM;
410 		goto clunk_fid;
411 	}
412 
413 	err = v9fs_fid_insert(ret, dentry);
414 	if (err < 0) {
415 		v9fs_fid_destroy(ret);
416 		goto clunk_fid;
417 	}
418 
419 	return ret;
420 
421 clunk_fid:
422 	v9fs_t_clunk(v9ses, nfid);
423 
424 error:
425 	kfree(fcall);
426 	return ERR_PTR(err);
427 }
428 */
429 
430 
431 /**
432  * v9fs_clear_inode - release an inode
433  * @inode: inode to release
434  *
435  */
436 void v9fs_evict_inode(struct inode *inode)
437 {
438 	struct v9fs_inode *v9inode = V9FS_I(inode);
439 
440 	truncate_inode_pages(inode->i_mapping, 0);
441 	end_writeback(inode);
442 	filemap_fdatawrite(inode->i_mapping);
443 
444 #ifdef CONFIG_9P_FSCACHE
445 	v9fs_cache_inode_put_cookie(inode);
446 #endif
447 	/* clunk the fid stashed in writeback_fid */
448 	if (v9inode->writeback_fid) {
449 		p9_client_clunk(v9inode->writeback_fid);
450 		v9inode->writeback_fid = NULL;
451 	}
452 }
453 
454 static int v9fs_test_inode(struct inode *inode, void *data)
455 {
456 	int umode;
457 	dev_t rdev;
458 	struct v9fs_inode *v9inode = V9FS_I(inode);
459 	struct p9_wstat *st = (struct p9_wstat *)data;
460 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
461 
462 	umode = p9mode2unixmode(v9ses, st, &rdev);
463 	/* don't match inode of different type */
464 	if ((inode->i_mode & S_IFMT) != (umode & S_IFMT))
465 		return 0;
466 
467 	/* compare qid details */
468 	if (memcmp(&v9inode->qid.version,
469 		   &st->qid.version, sizeof(v9inode->qid.version)))
470 		return 0;
471 
472 	if (v9inode->qid.type != st->qid.type)
473 		return 0;
474 	return 1;
475 }
476 
477 static int v9fs_test_new_inode(struct inode *inode, void *data)
478 {
479 	return 0;
480 }
481 
482 static int v9fs_set_inode(struct inode *inode,  void *data)
483 {
484 	struct v9fs_inode *v9inode = V9FS_I(inode);
485 	struct p9_wstat *st = (struct p9_wstat *)data;
486 
487 	memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
488 	return 0;
489 }
490 
491 static struct inode *v9fs_qid_iget(struct super_block *sb,
492 				   struct p9_qid *qid,
493 				   struct p9_wstat *st,
494 				   int new)
495 {
496 	dev_t rdev;
497 	int retval, umode;
498 	unsigned long i_ino;
499 	struct inode *inode;
500 	struct v9fs_session_info *v9ses = sb->s_fs_info;
501 	int (*test)(struct inode *, void *);
502 
503 	if (new)
504 		test = v9fs_test_new_inode;
505 	else
506 		test = v9fs_test_inode;
507 
508 	i_ino = v9fs_qid2ino(qid);
509 	inode = iget5_locked(sb, i_ino, test, v9fs_set_inode, st);
510 	if (!inode)
511 		return ERR_PTR(-ENOMEM);
512 	if (!(inode->i_state & I_NEW))
513 		return inode;
514 	/*
515 	 * initialize the inode with the stat info
516 	 * FIXME!! we may need support for stale inodes
517 	 * later.
518 	 */
519 	inode->i_ino = i_ino;
520 	umode = p9mode2unixmode(v9ses, st, &rdev);
521 	retval = v9fs_init_inode(v9ses, inode, umode, rdev);
522 	if (retval)
523 		goto error;
524 
525 	v9fs_stat2inode(st, inode, sb);
526 #ifdef CONFIG_9P_FSCACHE
527 	v9fs_cache_inode_get_cookie(inode);
528 #endif
529 	unlock_new_inode(inode);
530 	return inode;
531 error:
532 	unlock_new_inode(inode);
533 	iput(inode);
534 	return ERR_PTR(retval);
535 
536 }
537 
538 struct inode *
539 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
540 		    struct super_block *sb, int new)
541 {
542 	struct p9_wstat *st;
543 	struct inode *inode = NULL;
544 
545 	st = p9_client_stat(fid);
546 	if (IS_ERR(st))
547 		return ERR_CAST(st);
548 
549 	inode = v9fs_qid_iget(sb, &st->qid, st, new);
550 	p9stat_free(st);
551 	kfree(st);
552 	return inode;
553 }
554 
555 /**
556  * v9fs_at_to_dotl_flags- convert Linux specific AT flags to
557  * plan 9 AT flag.
558  * @flags: flags to convert
559  */
560 static int v9fs_at_to_dotl_flags(int flags)
561 {
562 	int rflags = 0;
563 	if (flags & AT_REMOVEDIR)
564 		rflags |= P9_DOTL_AT_REMOVEDIR;
565 	return rflags;
566 }
567 
568 /**
569  * v9fs_remove - helper function to remove files and directories
570  * @dir: directory inode that is being deleted
571  * @dentry:  dentry that is being deleted
572  * @rmdir: removing a directory
573  *
574  */
575 
576 static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
577 {
578 	struct inode *inode;
579 	int retval = -EOPNOTSUPP;
580 	struct p9_fid *v9fid, *dfid;
581 	struct v9fs_session_info *v9ses;
582 
583 	P9_DPRINTK(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
584 		   dir, dentry, flags);
585 
586 	v9ses = v9fs_inode2v9ses(dir);
587 	inode = dentry->d_inode;
588 	dfid = v9fs_fid_lookup(dentry->d_parent);
589 	if (IS_ERR(dfid)) {
590 		retval = PTR_ERR(dfid);
591 		P9_DPRINTK(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
592 		return retval;
593 	}
594 	if (v9fs_proto_dotl(v9ses))
595 		retval = p9_client_unlinkat(dfid, dentry->d_name.name,
596 					    v9fs_at_to_dotl_flags(flags));
597 	if (retval == -EOPNOTSUPP) {
598 		/* Try the one based on path */
599 		v9fid = v9fs_fid_clone(dentry);
600 		if (IS_ERR(v9fid))
601 			return PTR_ERR(v9fid);
602 		retval = p9_client_remove(v9fid);
603 	}
604 	if (!retval) {
605 		/*
606 		 * directories on unlink should have zero
607 		 * link count
608 		 */
609 		if (flags & AT_REMOVEDIR) {
610 			clear_nlink(inode);
611 			drop_nlink(dir);
612 		} else
613 			drop_nlink(inode);
614 
615 		v9fs_invalidate_inode_attr(inode);
616 		v9fs_invalidate_inode_attr(dir);
617 	}
618 	return retval;
619 }
620 
621 /**
622  * v9fs_create - Create a file
623  * @v9ses: session information
624  * @dir: directory that dentry is being created in
625  * @dentry:  dentry that is being created
626  * @extension: 9p2000.u extension string to support devices, etc.
627  * @perm: create permissions
628  * @mode: open mode
629  *
630  */
631 static struct p9_fid *
632 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
633 		struct dentry *dentry, char *extension, u32 perm, u8 mode)
634 {
635 	int err;
636 	char *name;
637 	struct p9_fid *dfid, *ofid, *fid;
638 	struct inode *inode;
639 
640 	P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
641 
642 	err = 0;
643 	ofid = NULL;
644 	fid = NULL;
645 	name = (char *) dentry->d_name.name;
646 	dfid = v9fs_fid_lookup(dentry->d_parent);
647 	if (IS_ERR(dfid)) {
648 		err = PTR_ERR(dfid);
649 		P9_DPRINTK(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
650 		return ERR_PTR(err);
651 	}
652 
653 	/* clone a fid to use for creation */
654 	ofid = p9_client_walk(dfid, 0, NULL, 1);
655 	if (IS_ERR(ofid)) {
656 		err = PTR_ERR(ofid);
657 		P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
658 		return ERR_PTR(err);
659 	}
660 
661 	err = p9_client_fcreate(ofid, name, perm, mode, extension);
662 	if (err < 0) {
663 		P9_DPRINTK(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
664 		goto error;
665 	}
666 
667 	/* now walk from the parent so we can get unopened fid */
668 	fid = p9_client_walk(dfid, 1, &name, 1);
669 	if (IS_ERR(fid)) {
670 		err = PTR_ERR(fid);
671 		P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
672 		fid = NULL;
673 		goto error;
674 	}
675 
676 	/* instantiate inode and assign the unopened fid to the dentry */
677 	inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
678 	if (IS_ERR(inode)) {
679 		err = PTR_ERR(inode);
680 		P9_DPRINTK(P9_DEBUG_VFS, "inode creation failed %d\n", err);
681 		goto error;
682 	}
683 	err = v9fs_fid_add(dentry, fid);
684 	if (err < 0)
685 		goto error;
686 	d_instantiate(dentry, inode);
687 	return ofid;
688 error:
689 	if (ofid)
690 		p9_client_clunk(ofid);
691 
692 	if (fid)
693 		p9_client_clunk(fid);
694 
695 	return ERR_PTR(err);
696 }
697 
698 /**
699  * v9fs_vfs_create - VFS hook to create files
700  * @dir: directory inode that is being created
701  * @dentry:  dentry that is being deleted
702  * @mode: create permissions
703  * @nd: path information
704  *
705  */
706 
707 static int
708 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
709 		struct nameidata *nd)
710 {
711 	int err;
712 	u32 perm;
713 	int flags;
714 	struct file *filp;
715 	struct v9fs_inode *v9inode;
716 	struct v9fs_session_info *v9ses;
717 	struct p9_fid *fid, *inode_fid;
718 
719 	err = 0;
720 	fid = NULL;
721 	v9ses = v9fs_inode2v9ses(dir);
722 	perm = unixmode2p9mode(v9ses, mode);
723 	if (nd)
724 		flags = nd->intent.open.flags;
725 	else
726 		flags = O_RDWR;
727 
728 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
729 				v9fs_uflags2omode(flags,
730 						v9fs_proto_dotu(v9ses)));
731 	if (IS_ERR(fid)) {
732 		err = PTR_ERR(fid);
733 		fid = NULL;
734 		goto error;
735 	}
736 
737 	v9fs_invalidate_inode_attr(dir);
738 	/* if we are opening a file, assign the open fid to the file */
739 	if (nd) {
740 		v9inode = V9FS_I(dentry->d_inode);
741 		mutex_lock(&v9inode->v_mutex);
742 		if (v9ses->cache && !v9inode->writeback_fid &&
743 		    ((flags & O_ACCMODE) != O_RDONLY)) {
744 			/*
745 			 * clone a fid and add it to writeback_fid
746 			 * we do it during open time instead of
747 			 * page dirty time via write_begin/page_mkwrite
748 			 * because we want write after unlink usecase
749 			 * to work.
750 			 */
751 			inode_fid = v9fs_writeback_fid(dentry);
752 			if (IS_ERR(inode_fid)) {
753 				err = PTR_ERR(inode_fid);
754 				mutex_unlock(&v9inode->v_mutex);
755 				goto error;
756 			}
757 			v9inode->writeback_fid = (void *) inode_fid;
758 		}
759 		mutex_unlock(&v9inode->v_mutex);
760 		filp = lookup_instantiate_filp(nd, dentry, generic_file_open);
761 		if (IS_ERR(filp)) {
762 			err = PTR_ERR(filp);
763 			goto error;
764 		}
765 
766 		filp->private_data = fid;
767 #ifdef CONFIG_9P_FSCACHE
768 		if (v9ses->cache)
769 			v9fs_cache_inode_set_cookie(dentry->d_inode, filp);
770 #endif
771 	} else
772 		p9_client_clunk(fid);
773 
774 	return 0;
775 
776 error:
777 	if (fid)
778 		p9_client_clunk(fid);
779 
780 	return err;
781 }
782 
783 /**
784  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
785  * @dir:  inode that is being unlinked
786  * @dentry: dentry that is being unlinked
787  * @mode: mode for new directory
788  *
789  */
790 
791 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
792 {
793 	int err;
794 	u32 perm;
795 	struct p9_fid *fid;
796 	struct v9fs_session_info *v9ses;
797 
798 	P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
799 	err = 0;
800 	v9ses = v9fs_inode2v9ses(dir);
801 	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
802 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
803 	if (IS_ERR(fid)) {
804 		err = PTR_ERR(fid);
805 		fid = NULL;
806 	} else {
807 		inc_nlink(dir);
808 		v9fs_invalidate_inode_attr(dir);
809 	}
810 
811 	if (fid)
812 		p9_client_clunk(fid);
813 
814 	return err;
815 }
816 
817 /**
818  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
819  * @dir:  inode that is being walked from
820  * @dentry: dentry that is being walked to?
821  * @nameidata: path data
822  *
823  */
824 
825 struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
826 				      struct nameidata *nameidata)
827 {
828 	struct dentry *res;
829 	struct super_block *sb;
830 	struct v9fs_session_info *v9ses;
831 	struct p9_fid *dfid, *fid;
832 	struct inode *inode;
833 	char *name;
834 	int result = 0;
835 
836 	P9_DPRINTK(P9_DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
837 		dir, dentry->d_name.name, dentry, nameidata);
838 
839 	if (dentry->d_name.len > NAME_MAX)
840 		return ERR_PTR(-ENAMETOOLONG);
841 
842 	sb = dir->i_sb;
843 	v9ses = v9fs_inode2v9ses(dir);
844 	/* We can walk d_parent because we hold the dir->i_mutex */
845 	dfid = v9fs_fid_lookup(dentry->d_parent);
846 	if (IS_ERR(dfid))
847 		return ERR_CAST(dfid);
848 
849 	name = (char *) dentry->d_name.name;
850 	fid = p9_client_walk(dfid, 1, &name, 1);
851 	if (IS_ERR(fid)) {
852 		result = PTR_ERR(fid);
853 		if (result == -ENOENT) {
854 			inode = NULL;
855 			goto inst_out;
856 		}
857 
858 		return ERR_PTR(result);
859 	}
860 	/*
861 	 * Make sure we don't use a wrong inode due to parallel
862 	 * unlink. For cached mode create calls request for new
863 	 * inode. But with cache disabled, lookup should do this.
864 	 */
865 	if (v9ses->cache)
866 		inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
867 	else
868 		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
869 	if (IS_ERR(inode)) {
870 		result = PTR_ERR(inode);
871 		inode = NULL;
872 		goto error;
873 	}
874 	result = v9fs_fid_add(dentry, fid);
875 	if (result < 0)
876 		goto error_iput;
877 inst_out:
878 	/*
879 	 * If we had a rename on the server and a parallel lookup
880 	 * for the new name, then make sure we instantiate with
881 	 * the new name. ie look up for a/b, while on server somebody
882 	 * moved b under k and client parallely did a lookup for
883 	 * k/b.
884 	 */
885 	res = d_materialise_unique(dentry, inode);
886 	if (!IS_ERR(res))
887 		return res;
888 	result = PTR_ERR(res);
889 error_iput:
890 	iput(inode);
891 error:
892 	p9_client_clunk(fid);
893 
894 	return ERR_PTR(result);
895 }
896 
897 /**
898  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
899  * @i:  inode that is being unlinked
900  * @d: dentry that is being unlinked
901  *
902  */
903 
904 int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
905 {
906 	return v9fs_remove(i, d, 0);
907 }
908 
909 /**
910  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
911  * @i:  inode that is being unlinked
912  * @d: dentry that is being unlinked
913  *
914  */
915 
916 int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
917 {
918 	return v9fs_remove(i, d, AT_REMOVEDIR);
919 }
920 
921 /**
922  * v9fs_vfs_rename - VFS hook to rename an inode
923  * @old_dir:  old dir inode
924  * @old_dentry: old dentry
925  * @new_dir: new dir inode
926  * @new_dentry: new dentry
927  *
928  */
929 
930 int
931 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
932 		struct inode *new_dir, struct dentry *new_dentry)
933 {
934 	int retval;
935 	struct inode *old_inode;
936 	struct inode *new_inode;
937 	struct v9fs_session_info *v9ses;
938 	struct p9_fid *oldfid;
939 	struct p9_fid *olddirfid;
940 	struct p9_fid *newdirfid;
941 	struct p9_wstat wstat;
942 
943 	P9_DPRINTK(P9_DEBUG_VFS, "\n");
944 	retval = 0;
945 	old_inode = old_dentry->d_inode;
946 	new_inode = new_dentry->d_inode;
947 	v9ses = v9fs_inode2v9ses(old_inode);
948 	oldfid = v9fs_fid_lookup(old_dentry);
949 	if (IS_ERR(oldfid))
950 		return PTR_ERR(oldfid);
951 
952 	olddirfid = v9fs_fid_clone(old_dentry->d_parent);
953 	if (IS_ERR(olddirfid)) {
954 		retval = PTR_ERR(olddirfid);
955 		goto done;
956 	}
957 
958 	newdirfid = v9fs_fid_clone(new_dentry->d_parent);
959 	if (IS_ERR(newdirfid)) {
960 		retval = PTR_ERR(newdirfid);
961 		goto clunk_olddir;
962 	}
963 
964 	down_write(&v9ses->rename_sem);
965 	if (v9fs_proto_dotl(v9ses)) {
966 		retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
967 					    newdirfid, new_dentry->d_name.name);
968 		if (retval == -EOPNOTSUPP)
969 			retval = p9_client_rename(oldfid, newdirfid,
970 						  new_dentry->d_name.name);
971 		if (retval != -EOPNOTSUPP)
972 			goto clunk_newdir;
973 	}
974 	if (old_dentry->d_parent != new_dentry->d_parent) {
975 		/*
976 		 * 9P .u can only handle file rename in the same directory
977 		 */
978 
979 		P9_DPRINTK(P9_DEBUG_ERROR,
980 				"old dir and new dir are different\n");
981 		retval = -EXDEV;
982 		goto clunk_newdir;
983 	}
984 	v9fs_blank_wstat(&wstat);
985 	wstat.muid = v9ses->uname;
986 	wstat.name = (char *) new_dentry->d_name.name;
987 	retval = p9_client_wstat(oldfid, &wstat);
988 
989 clunk_newdir:
990 	if (!retval) {
991 		if (new_inode) {
992 			if (S_ISDIR(new_inode->i_mode))
993 				clear_nlink(new_inode);
994 			else
995 				drop_nlink(new_inode);
996 		}
997 		if (S_ISDIR(old_inode->i_mode)) {
998 			if (!new_inode)
999 				inc_nlink(new_dir);
1000 			drop_nlink(old_dir);
1001 		}
1002 		v9fs_invalidate_inode_attr(old_inode);
1003 		v9fs_invalidate_inode_attr(old_dir);
1004 		v9fs_invalidate_inode_attr(new_dir);
1005 
1006 		/* successful rename */
1007 		d_move(old_dentry, new_dentry);
1008 	}
1009 	up_write(&v9ses->rename_sem);
1010 	p9_client_clunk(newdirfid);
1011 
1012 clunk_olddir:
1013 	p9_client_clunk(olddirfid);
1014 
1015 done:
1016 	return retval;
1017 }
1018 
1019 /**
1020  * v9fs_vfs_getattr - retrieve file metadata
1021  * @mnt: mount information
1022  * @dentry: file to get attributes on
1023  * @stat: metadata structure to populate
1024  *
1025  */
1026 
1027 static int
1028 v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1029 		 struct kstat *stat)
1030 {
1031 	int err;
1032 	struct v9fs_session_info *v9ses;
1033 	struct p9_fid *fid;
1034 	struct p9_wstat *st;
1035 
1036 	P9_DPRINTK(P9_DEBUG_VFS, "dentry: %p\n", dentry);
1037 	err = -EPERM;
1038 	v9ses = v9fs_dentry2v9ses(dentry);
1039 	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
1040 		generic_fillattr(dentry->d_inode, stat);
1041 		return 0;
1042 	}
1043 	fid = v9fs_fid_lookup(dentry);
1044 	if (IS_ERR(fid))
1045 		return PTR_ERR(fid);
1046 
1047 	st = p9_client_stat(fid);
1048 	if (IS_ERR(st))
1049 		return PTR_ERR(st);
1050 
1051 	v9fs_stat2inode(st, dentry->d_inode, dentry->d_inode->i_sb);
1052 	generic_fillattr(dentry->d_inode, stat);
1053 
1054 	p9stat_free(st);
1055 	kfree(st);
1056 	return 0;
1057 }
1058 
1059 /**
1060  * v9fs_vfs_setattr - set file metadata
1061  * @dentry: file whose metadata to set
1062  * @iattr: metadata assignment structure
1063  *
1064  */
1065 
1066 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
1067 {
1068 	int retval;
1069 	struct v9fs_session_info *v9ses;
1070 	struct p9_fid *fid;
1071 	struct p9_wstat wstat;
1072 
1073 	P9_DPRINTK(P9_DEBUG_VFS, "\n");
1074 	retval = inode_change_ok(dentry->d_inode, iattr);
1075 	if (retval)
1076 		return retval;
1077 
1078 	retval = -EPERM;
1079 	v9ses = v9fs_dentry2v9ses(dentry);
1080 	fid = v9fs_fid_lookup(dentry);
1081 	if(IS_ERR(fid))
1082 		return PTR_ERR(fid);
1083 
1084 	v9fs_blank_wstat(&wstat);
1085 	if (iattr->ia_valid & ATTR_MODE)
1086 		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
1087 
1088 	if (iattr->ia_valid & ATTR_MTIME)
1089 		wstat.mtime = iattr->ia_mtime.tv_sec;
1090 
1091 	if (iattr->ia_valid & ATTR_ATIME)
1092 		wstat.atime = iattr->ia_atime.tv_sec;
1093 
1094 	if (iattr->ia_valid & ATTR_SIZE)
1095 		wstat.length = iattr->ia_size;
1096 
1097 	if (v9fs_proto_dotu(v9ses)) {
1098 		if (iattr->ia_valid & ATTR_UID)
1099 			wstat.n_uid = iattr->ia_uid;
1100 
1101 		if (iattr->ia_valid & ATTR_GID)
1102 			wstat.n_gid = iattr->ia_gid;
1103 	}
1104 
1105 	/* Write all dirty data */
1106 	if (S_ISREG(dentry->d_inode->i_mode))
1107 		filemap_write_and_wait(dentry->d_inode->i_mapping);
1108 
1109 	retval = p9_client_wstat(fid, &wstat);
1110 	if (retval < 0)
1111 		return retval;
1112 
1113 	if ((iattr->ia_valid & ATTR_SIZE) &&
1114 	    iattr->ia_size != i_size_read(dentry->d_inode))
1115 		truncate_setsize(dentry->d_inode, iattr->ia_size);
1116 
1117 	v9fs_invalidate_inode_attr(dentry->d_inode);
1118 
1119 	setattr_copy(dentry->d_inode, iattr);
1120 	mark_inode_dirty(dentry->d_inode);
1121 	return 0;
1122 }
1123 
1124 /**
1125  * v9fs_stat2inode - populate an inode structure with mistat info
1126  * @stat: Plan 9 metadata (mistat) structure
1127  * @inode: inode to populate
1128  * @sb: superblock of filesystem
1129  *
1130  */
1131 
1132 void
1133 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
1134 	struct super_block *sb)
1135 {
1136 	mode_t mode;
1137 	char ext[32];
1138 	char tag_name[14];
1139 	unsigned int i_nlink;
1140 	struct v9fs_session_info *v9ses = sb->s_fs_info;
1141 	struct v9fs_inode *v9inode = V9FS_I(inode);
1142 
1143 	inode->i_nlink = 1;
1144 
1145 	inode->i_atime.tv_sec = stat->atime;
1146 	inode->i_mtime.tv_sec = stat->mtime;
1147 	inode->i_ctime.tv_sec = stat->mtime;
1148 
1149 	inode->i_uid = v9ses->dfltuid;
1150 	inode->i_gid = v9ses->dfltgid;
1151 
1152 	if (v9fs_proto_dotu(v9ses)) {
1153 		inode->i_uid = stat->n_uid;
1154 		inode->i_gid = stat->n_gid;
1155 	}
1156 	if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
1157 		if (v9fs_proto_dotu(v9ses) && (stat->extension[0] != '\0')) {
1158 			/*
1159 			 * Hadlink support got added later to
1160 			 * to the .u extension. So there can be
1161 			 * server out there that doesn't support
1162 			 * this even with .u extension. So check
1163 			 * for non NULL stat->extension
1164 			 */
1165 			strncpy(ext, stat->extension, sizeof(ext));
1166 			/* HARDLINKCOUNT %u */
1167 			sscanf(ext, "%13s %u", tag_name, &i_nlink);
1168 			if (!strncmp(tag_name, "HARDLINKCOUNT", 13))
1169 				inode->i_nlink = i_nlink;
1170 		}
1171 	}
1172 	mode = stat->mode & S_IALLUGO;
1173 	mode |= inode->i_mode & ~S_IALLUGO;
1174 	inode->i_mode = mode;
1175 	i_size_write(inode, stat->length);
1176 
1177 	/* not real number of blocks, but 512 byte ones ... */
1178 	inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
1179 	v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
1180 }
1181 
1182 /**
1183  * v9fs_qid2ino - convert qid into inode number
1184  * @qid: qid to hash
1185  *
1186  * BUG: potential for inode number collisions?
1187  */
1188 
1189 ino_t v9fs_qid2ino(struct p9_qid *qid)
1190 {
1191 	u64 path = qid->path + 2;
1192 	ino_t i = 0;
1193 
1194 	if (sizeof(ino_t) == sizeof(path))
1195 		memcpy(&i, &path, sizeof(ino_t));
1196 	else
1197 		i = (ino_t) (path ^ (path >> 32));
1198 
1199 	return i;
1200 }
1201 
1202 /**
1203  * v9fs_readlink - read a symlink's location (internal version)
1204  * @dentry: dentry for symlink
1205  * @buffer: buffer to load symlink location into
1206  * @buflen: length of buffer
1207  *
1208  */
1209 
1210 static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
1211 {
1212 	int retval;
1213 
1214 	struct v9fs_session_info *v9ses;
1215 	struct p9_fid *fid;
1216 	struct p9_wstat *st;
1217 
1218 	P9_DPRINTK(P9_DEBUG_VFS, " %s\n", dentry->d_name.name);
1219 	retval = -EPERM;
1220 	v9ses = v9fs_dentry2v9ses(dentry);
1221 	fid = v9fs_fid_lookup(dentry);
1222 	if (IS_ERR(fid))
1223 		return PTR_ERR(fid);
1224 
1225 	if (!v9fs_proto_dotu(v9ses))
1226 		return -EBADF;
1227 
1228 	st = p9_client_stat(fid);
1229 	if (IS_ERR(st))
1230 		return PTR_ERR(st);
1231 
1232 	if (!(st->mode & P9_DMSYMLINK)) {
1233 		retval = -EINVAL;
1234 		goto done;
1235 	}
1236 
1237 	/* copy extension buffer into buffer */
1238 	strncpy(buffer, st->extension, buflen);
1239 
1240 	P9_DPRINTK(P9_DEBUG_VFS,
1241 		"%s -> %s (%s)\n", dentry->d_name.name, st->extension, buffer);
1242 
1243 	retval = strnlen(buffer, buflen);
1244 done:
1245 	p9stat_free(st);
1246 	kfree(st);
1247 	return retval;
1248 }
1249 
1250 /**
1251  * v9fs_vfs_follow_link - follow a symlink path
1252  * @dentry: dentry for symlink
1253  * @nd: nameidata
1254  *
1255  */
1256 
1257 static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
1258 {
1259 	int len = 0;
1260 	char *link = __getname();
1261 
1262 	P9_DPRINTK(P9_DEBUG_VFS, "%s n", dentry->d_name.name);
1263 
1264 	if (!link)
1265 		link = ERR_PTR(-ENOMEM);
1266 	else {
1267 		len = v9fs_readlink(dentry, link, PATH_MAX);
1268 
1269 		if (len < 0) {
1270 			__putname(link);
1271 			link = ERR_PTR(len);
1272 		} else
1273 			link[min(len, PATH_MAX-1)] = 0;
1274 	}
1275 	nd_set_link(nd, link);
1276 
1277 	return NULL;
1278 }
1279 
1280 /**
1281  * v9fs_vfs_put_link - release a symlink path
1282  * @dentry: dentry for symlink
1283  * @nd: nameidata
1284  * @p: unused
1285  *
1286  */
1287 
1288 void
1289 v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
1290 {
1291 	char *s = nd_get_link(nd);
1292 
1293 	P9_DPRINTK(P9_DEBUG_VFS, " %s %s\n", dentry->d_name.name,
1294 		IS_ERR(s) ? "<error>" : s);
1295 	if (!IS_ERR(s))
1296 		__putname(s);
1297 }
1298 
1299 /**
1300  * v9fs_vfs_mkspecial - create a special file
1301  * @dir: inode to create special file in
1302  * @dentry: dentry to create
1303  * @mode: mode to create special file
1304  * @extension: 9p2000.u format extension string representing special file
1305  *
1306  */
1307 
1308 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1309 	int mode, const char *extension)
1310 {
1311 	u32 perm;
1312 	struct p9_fid *fid;
1313 	struct v9fs_session_info *v9ses;
1314 
1315 	v9ses = v9fs_inode2v9ses(dir);
1316 	if (!v9fs_proto_dotu(v9ses)) {
1317 		P9_DPRINTK(P9_DEBUG_ERROR, "not extended\n");
1318 		return -EPERM;
1319 	}
1320 
1321 	perm = unixmode2p9mode(v9ses, mode);
1322 	fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1323 								P9_OREAD);
1324 	if (IS_ERR(fid))
1325 		return PTR_ERR(fid);
1326 
1327 	v9fs_invalidate_inode_attr(dir);
1328 	p9_client_clunk(fid);
1329 	return 0;
1330 }
1331 
1332 /**
1333  * v9fs_vfs_symlink - helper function to create symlinks
1334  * @dir: directory inode containing symlink
1335  * @dentry: dentry for symlink
1336  * @symname: symlink data
1337  *
1338  * See Also: 9P2000.u RFC for more information
1339  *
1340  */
1341 
1342 static int
1343 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1344 {
1345 	P9_DPRINTK(P9_DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino,
1346 					dentry->d_name.name, symname);
1347 
1348 	return v9fs_vfs_mkspecial(dir, dentry, S_IFLNK, symname);
1349 }
1350 
1351 /**
1352  * v9fs_vfs_link - create a hardlink
1353  * @old_dentry: dentry for file to link to
1354  * @dir: inode destination for new link
1355  * @dentry: dentry for link
1356  *
1357  */
1358 
1359 static int
1360 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1361 	      struct dentry *dentry)
1362 {
1363 	int retval;
1364 	char *name;
1365 	struct p9_fid *oldfid;
1366 
1367 	P9_DPRINTK(P9_DEBUG_VFS,
1368 		" %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
1369 		old_dentry->d_name.name);
1370 
1371 	oldfid = v9fs_fid_clone(old_dentry);
1372 	if (IS_ERR(oldfid))
1373 		return PTR_ERR(oldfid);
1374 
1375 	name = __getname();
1376 	if (unlikely(!name)) {
1377 		retval = -ENOMEM;
1378 		goto clunk_fid;
1379 	}
1380 
1381 	sprintf(name, "%d\n", oldfid->fid);
1382 	retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1383 	__putname(name);
1384 	if (!retval) {
1385 		v9fs_refresh_inode(oldfid, old_dentry->d_inode);
1386 		v9fs_invalidate_inode_attr(dir);
1387 	}
1388 clunk_fid:
1389 	p9_client_clunk(oldfid);
1390 	return retval;
1391 }
1392 
1393 /**
1394  * v9fs_vfs_mknod - create a special file
1395  * @dir: inode destination for new link
1396  * @dentry: dentry for file
1397  * @mode: mode for creation
1398  * @rdev: device associated with special file
1399  *
1400  */
1401 
1402 static int
1403 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
1404 {
1405 	int retval;
1406 	char *name;
1407 
1408 	P9_DPRINTK(P9_DEBUG_VFS,
1409 		" %lu,%s mode: %x MAJOR: %u MINOR: %u\n", dir->i_ino,
1410 		dentry->d_name.name, mode, MAJOR(rdev), MINOR(rdev));
1411 
1412 	if (!new_valid_dev(rdev))
1413 		return -EINVAL;
1414 
1415 	name = __getname();
1416 	if (!name)
1417 		return -ENOMEM;
1418 	/* build extension */
1419 	if (S_ISBLK(mode))
1420 		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1421 	else if (S_ISCHR(mode))
1422 		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1423 	else if (S_ISFIFO(mode))
1424 		*name = 0;
1425 	else if (S_ISSOCK(mode))
1426 		*name = 0;
1427 	else {
1428 		__putname(name);
1429 		return -EINVAL;
1430 	}
1431 
1432 	retval = v9fs_vfs_mkspecial(dir, dentry, mode, name);
1433 	__putname(name);
1434 
1435 	return retval;
1436 }
1437 
1438 int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
1439 {
1440 	int umode;
1441 	dev_t rdev;
1442 	loff_t i_size;
1443 	struct p9_wstat *st;
1444 	struct v9fs_session_info *v9ses;
1445 
1446 	v9ses = v9fs_inode2v9ses(inode);
1447 	st = p9_client_stat(fid);
1448 	if (IS_ERR(st))
1449 		return PTR_ERR(st);
1450 	/*
1451 	 * Don't update inode if the file type is different
1452 	 */
1453 	umode = p9mode2unixmode(v9ses, st, &rdev);
1454 	if ((inode->i_mode & S_IFMT) != (umode & S_IFMT))
1455 		goto out;
1456 
1457 	spin_lock(&inode->i_lock);
1458 	/*
1459 	 * We don't want to refresh inode->i_size,
1460 	 * because we may have cached data
1461 	 */
1462 	i_size = inode->i_size;
1463 	v9fs_stat2inode(st, inode, inode->i_sb);
1464 	if (v9ses->cache)
1465 		inode->i_size = i_size;
1466 	spin_unlock(&inode->i_lock);
1467 out:
1468 	p9stat_free(st);
1469 	kfree(st);
1470 	return 0;
1471 }
1472 
1473 static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1474 	.create = v9fs_vfs_create,
1475 	.lookup = v9fs_vfs_lookup,
1476 	.symlink = v9fs_vfs_symlink,
1477 	.link = v9fs_vfs_link,
1478 	.unlink = v9fs_vfs_unlink,
1479 	.mkdir = v9fs_vfs_mkdir,
1480 	.rmdir = v9fs_vfs_rmdir,
1481 	.mknod = v9fs_vfs_mknod,
1482 	.rename = v9fs_vfs_rename,
1483 	.getattr = v9fs_vfs_getattr,
1484 	.setattr = v9fs_vfs_setattr,
1485 };
1486 
1487 static const struct inode_operations v9fs_dir_inode_operations = {
1488 	.create = v9fs_vfs_create,
1489 	.lookup = v9fs_vfs_lookup,
1490 	.unlink = v9fs_vfs_unlink,
1491 	.mkdir = v9fs_vfs_mkdir,
1492 	.rmdir = v9fs_vfs_rmdir,
1493 	.mknod = v9fs_vfs_mknod,
1494 	.rename = v9fs_vfs_rename,
1495 	.getattr = v9fs_vfs_getattr,
1496 	.setattr = v9fs_vfs_setattr,
1497 };
1498 
1499 static const struct inode_operations v9fs_file_inode_operations = {
1500 	.getattr = v9fs_vfs_getattr,
1501 	.setattr = v9fs_vfs_setattr,
1502 };
1503 
1504 static const struct inode_operations v9fs_symlink_inode_operations = {
1505 	.readlink = generic_readlink,
1506 	.follow_link = v9fs_vfs_follow_link,
1507 	.put_link = v9fs_vfs_put_link,
1508 	.getattr = v9fs_vfs_getattr,
1509 	.setattr = v9fs_vfs_setattr,
1510 };
1511 
1512