xref: /linux/fs/9p/vfs_inode.c (revision 0dd9ac63ce26ec87b080ca9c3e6efed33c23ace6)
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 <net/9p/9p.h>
39 #include <net/9p/client.h>
40 
41 #include "v9fs.h"
42 #include "v9fs_vfs.h"
43 #include "fid.h"
44 #include "cache.h"
45 
46 static const struct inode_operations v9fs_dir_inode_operations;
47 static const struct inode_operations v9fs_dir_inode_operations_dotu;
48 static const struct inode_operations v9fs_dir_inode_operations_dotl;
49 static const struct inode_operations v9fs_file_inode_operations;
50 static const struct inode_operations v9fs_file_inode_operations_dotl;
51 static const struct inode_operations v9fs_symlink_inode_operations;
52 static const struct inode_operations v9fs_symlink_inode_operations_dotl;
53 
54 /**
55  * unixmode2p9mode - convert unix mode bits to plan 9
56  * @v9ses: v9fs session information
57  * @mode: mode to convert
58  *
59  */
60 
61 static int unixmode2p9mode(struct v9fs_session_info *v9ses, int mode)
62 {
63 	int res;
64 	res = mode & 0777;
65 	if (S_ISDIR(mode))
66 		res |= P9_DMDIR;
67 	if (v9fs_proto_dotu(v9ses)) {
68 		if (S_ISLNK(mode))
69 			res |= P9_DMSYMLINK;
70 		if (v9ses->nodev == 0) {
71 			if (S_ISSOCK(mode))
72 				res |= P9_DMSOCKET;
73 			if (S_ISFIFO(mode))
74 				res |= P9_DMNAMEDPIPE;
75 			if (S_ISBLK(mode))
76 				res |= P9_DMDEVICE;
77 			if (S_ISCHR(mode))
78 				res |= P9_DMDEVICE;
79 		}
80 
81 		if ((mode & S_ISUID) == S_ISUID)
82 			res |= P9_DMSETUID;
83 		if ((mode & S_ISGID) == S_ISGID)
84 			res |= P9_DMSETGID;
85 		if ((mode & S_ISVTX) == S_ISVTX)
86 			res |= P9_DMSETVTX;
87 		if ((mode & P9_DMLINK))
88 			res |= P9_DMLINK;
89 	}
90 
91 	return res;
92 }
93 
94 /**
95  * p9mode2unixmode- convert plan9 mode bits to unix mode bits
96  * @v9ses: v9fs session information
97  * @mode: mode to convert
98  *
99  */
100 
101 static int p9mode2unixmode(struct v9fs_session_info *v9ses, int mode)
102 {
103 	int res;
104 
105 	res = mode & 0777;
106 
107 	if ((mode & P9_DMDIR) == P9_DMDIR)
108 		res |= S_IFDIR;
109 	else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
110 		res |= S_IFLNK;
111 	else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
112 		 && (v9ses->nodev == 0))
113 		res |= S_IFSOCK;
114 	else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
115 		 && (v9ses->nodev == 0))
116 		res |= S_IFIFO;
117 	else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
118 		 && (v9ses->nodev == 0))
119 		res |= S_IFBLK;
120 	else
121 		res |= S_IFREG;
122 
123 	if (v9fs_proto_dotu(v9ses)) {
124 		if ((mode & P9_DMSETUID) == P9_DMSETUID)
125 			res |= S_ISUID;
126 
127 		if ((mode & P9_DMSETGID) == P9_DMSETGID)
128 			res |= S_ISGID;
129 
130 		if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
131 			res |= S_ISVTX;
132 	}
133 
134 	return res;
135 }
136 
137 /**
138  * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
139  * @uflags: flags to convert
140  * @extended: if .u extensions are active
141  */
142 
143 int v9fs_uflags2omode(int uflags, int extended)
144 {
145 	int ret;
146 
147 	ret = 0;
148 	switch (uflags&3) {
149 	default:
150 	case O_RDONLY:
151 		ret = P9_OREAD;
152 		break;
153 
154 	case O_WRONLY:
155 		ret = P9_OWRITE;
156 		break;
157 
158 	case O_RDWR:
159 		ret = P9_ORDWR;
160 		break;
161 	}
162 
163 	if (uflags & O_TRUNC)
164 		ret |= P9_OTRUNC;
165 
166 	if (extended) {
167 		if (uflags & O_EXCL)
168 			ret |= P9_OEXCL;
169 
170 		if (uflags & O_APPEND)
171 			ret |= P9_OAPPEND;
172 	}
173 
174 	return ret;
175 }
176 
177 /**
178  * v9fs_blank_wstat - helper function to setup a 9P stat structure
179  * @wstat: structure to initialize
180  *
181  */
182 
183 void
184 v9fs_blank_wstat(struct p9_wstat *wstat)
185 {
186 	wstat->type = ~0;
187 	wstat->dev = ~0;
188 	wstat->qid.type = ~0;
189 	wstat->qid.version = ~0;
190 	*((long long *)&wstat->qid.path) = ~0;
191 	wstat->mode = ~0;
192 	wstat->atime = ~0;
193 	wstat->mtime = ~0;
194 	wstat->length = ~0;
195 	wstat->name = NULL;
196 	wstat->uid = NULL;
197 	wstat->gid = NULL;
198 	wstat->muid = NULL;
199 	wstat->n_uid = ~0;
200 	wstat->n_gid = ~0;
201 	wstat->n_muid = ~0;
202 	wstat->extension = NULL;
203 }
204 
205 #ifdef CONFIG_9P_FSCACHE
206 /**
207  * v9fs_alloc_inode - helper function to allocate an inode
208  * This callback is executed before setting up the inode so that we
209  * can associate a vcookie with each inode.
210  *
211  */
212 
213 struct inode *v9fs_alloc_inode(struct super_block *sb)
214 {
215 	struct v9fs_cookie *vcookie;
216 	vcookie = (struct v9fs_cookie *)kmem_cache_alloc(vcookie_cache,
217 							 GFP_KERNEL);
218 	if (!vcookie)
219 		return NULL;
220 
221 	vcookie->fscache = NULL;
222 	vcookie->qid = NULL;
223 	spin_lock_init(&vcookie->lock);
224 	return &vcookie->inode;
225 }
226 
227 /**
228  * v9fs_destroy_inode - destroy an inode
229  *
230  */
231 
232 void v9fs_destroy_inode(struct inode *inode)
233 {
234 	kmem_cache_free(vcookie_cache, v9fs_inode2cookie(inode));
235 }
236 #endif
237 
238 /**
239  * v9fs_get_inode - helper function to setup an inode
240  * @sb: superblock
241  * @mode: mode to setup inode with
242  *
243  */
244 
245 struct inode *v9fs_get_inode(struct super_block *sb, int mode)
246 {
247 	int err;
248 	struct inode *inode;
249 	struct v9fs_session_info *v9ses = sb->s_fs_info;
250 
251 	P9_DPRINTK(P9_DEBUG_VFS, "super block: %p mode: %o\n", sb, mode);
252 
253 	inode = new_inode(sb);
254 	if (!inode) {
255 		P9_EPRINTK(KERN_WARNING, "Problem allocating inode\n");
256 		return ERR_PTR(-ENOMEM);
257 	}
258 
259 	inode_init_owner(inode, NULL, mode);
260 	inode->i_blocks = 0;
261 	inode->i_rdev = 0;
262 	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
263 	inode->i_mapping->a_ops = &v9fs_addr_operations;
264 
265 	switch (mode & S_IFMT) {
266 	case S_IFIFO:
267 	case S_IFBLK:
268 	case S_IFCHR:
269 	case S_IFSOCK:
270 		if (!v9fs_proto_dotu(v9ses)) {
271 			P9_DPRINTK(P9_DEBUG_ERROR,
272 				   "special files without extended mode\n");
273 			err = -EINVAL;
274 			goto error;
275 		}
276 		init_special_inode(inode, inode->i_mode, inode->i_rdev);
277 		break;
278 	case S_IFREG:
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 {
283 			inode->i_op = &v9fs_file_inode_operations;
284 			inode->i_fop = &v9fs_file_operations;
285 		}
286 
287 		break;
288 
289 	case S_IFLNK:
290 		if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
291 			P9_DPRINTK(P9_DEBUG_ERROR, "extended modes used with "
292 						"legacy protocol.\n");
293 			err = -EINVAL;
294 			goto error;
295 		}
296 
297 		if (v9fs_proto_dotl(v9ses))
298 			inode->i_op = &v9fs_symlink_inode_operations_dotl;
299 		else
300 			inode->i_op = &v9fs_symlink_inode_operations;
301 
302 		break;
303 	case S_IFDIR:
304 		inc_nlink(inode);
305 		if (v9fs_proto_dotl(v9ses))
306 			inode->i_op = &v9fs_dir_inode_operations_dotl;
307 		else if (v9fs_proto_dotu(v9ses))
308 			inode->i_op = &v9fs_dir_inode_operations_dotu;
309 		else
310 			inode->i_op = &v9fs_dir_inode_operations;
311 
312 		if (v9fs_proto_dotl(v9ses))
313 			inode->i_fop = &v9fs_dir_operations_dotl;
314 		else
315 			inode->i_fop = &v9fs_dir_operations;
316 
317 		break;
318 	default:
319 		P9_DPRINTK(P9_DEBUG_ERROR, "BAD mode 0x%x S_IFMT 0x%x\n",
320 			   mode, mode & S_IFMT);
321 		err = -EINVAL;
322 		goto error;
323 	}
324 
325 	return inode;
326 
327 error:
328 	iput(inode);
329 	return ERR_PTR(err);
330 }
331 
332 /*
333 static struct v9fs_fid*
334 v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
335 {
336 	int err;
337 	int nfid;
338 	struct v9fs_fid *ret;
339 	struct v9fs_fcall *fcall;
340 
341 	nfid = v9fs_get_idpool(&v9ses->fidpool);
342 	if (nfid < 0) {
343 		eprintk(KERN_WARNING, "no free fids available\n");
344 		return ERR_PTR(-ENOSPC);
345 	}
346 
347 	err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
348 		&fcall);
349 
350 	if (err < 0) {
351 		if (fcall && fcall->id == RWALK)
352 			goto clunk_fid;
353 
354 		PRINT_FCALL_ERROR("walk error", fcall);
355 		v9fs_put_idpool(nfid, &v9ses->fidpool);
356 		goto error;
357 	}
358 
359 	kfree(fcall);
360 	fcall = NULL;
361 	ret = v9fs_fid_create(v9ses, nfid);
362 	if (!ret) {
363 		err = -ENOMEM;
364 		goto clunk_fid;
365 	}
366 
367 	err = v9fs_fid_insert(ret, dentry);
368 	if (err < 0) {
369 		v9fs_fid_destroy(ret);
370 		goto clunk_fid;
371 	}
372 
373 	return ret;
374 
375 clunk_fid:
376 	v9fs_t_clunk(v9ses, nfid);
377 
378 error:
379 	kfree(fcall);
380 	return ERR_PTR(err);
381 }
382 */
383 
384 
385 /**
386  * v9fs_clear_inode - release an inode
387  * @inode: inode to release
388  *
389  */
390 void v9fs_clear_inode(struct inode *inode)
391 {
392 	filemap_fdatawrite(inode->i_mapping);
393 
394 #ifdef CONFIG_9P_FSCACHE
395 	v9fs_cache_inode_put_cookie(inode);
396 #endif
397 }
398 
399 /**
400  * v9fs_inode_from_fid - populate an inode by issuing a attribute request
401  * @v9ses: session information
402  * @fid: fid to issue attribute request for
403  * @sb: superblock on which to create inode
404  *
405  */
406 
407 static struct inode *
408 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
409 	struct super_block *sb)
410 {
411 	int err, umode;
412 	struct inode *ret;
413 	struct p9_wstat *st;
414 
415 	ret = NULL;
416 	st = p9_client_stat(fid);
417 	if (IS_ERR(st))
418 		return ERR_CAST(st);
419 
420 	umode = p9mode2unixmode(v9ses, st->mode);
421 	ret = v9fs_get_inode(sb, umode);
422 	if (IS_ERR(ret)) {
423 		err = PTR_ERR(ret);
424 		goto error;
425 	}
426 
427 	v9fs_stat2inode(st, ret, sb);
428 	ret->i_ino = v9fs_qid2ino(&st->qid);
429 
430 #ifdef CONFIG_9P_FSCACHE
431 	v9fs_vcookie_set_qid(ret, &st->qid);
432 	v9fs_cache_inode_get_cookie(ret);
433 #endif
434 	p9stat_free(st);
435 	kfree(st);
436 
437 	return ret;
438 
439 error:
440 	p9stat_free(st);
441 	kfree(st);
442 	return ERR_PTR(err);
443 }
444 
445 /**
446  * v9fs_remove - helper function to remove files and directories
447  * @dir: directory inode that is being deleted
448  * @file:  dentry that is being deleted
449  * @rmdir: removing a directory
450  *
451  */
452 
453 static int v9fs_remove(struct inode *dir, struct dentry *file, int rmdir)
454 {
455 	int retval;
456 	struct inode *file_inode;
457 	struct p9_fid *v9fid;
458 
459 	P9_DPRINTK(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %d\n", dir, file,
460 		rmdir);
461 
462 	file_inode = file->d_inode;
463 	v9fid = v9fs_fid_clone(file);
464 	if (IS_ERR(v9fid))
465 		return PTR_ERR(v9fid);
466 
467 	retval = p9_client_remove(v9fid);
468 	if (!retval)
469 		drop_nlink(file_inode);
470 	return retval;
471 }
472 
473 static int
474 v9fs_open_created(struct inode *inode, struct file *file)
475 {
476 	return 0;
477 }
478 
479 
480 /**
481  * v9fs_create - Create a file
482  * @v9ses: session information
483  * @dir: directory that dentry is being created in
484  * @dentry:  dentry that is being created
485  * @extension: 9p2000.u extension string to support devices, etc.
486  * @perm: create permissions
487  * @mode: open mode
488  *
489  */
490 static struct p9_fid *
491 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
492 		struct dentry *dentry, char *extension, u32 perm, u8 mode)
493 {
494 	int err;
495 	char *name;
496 	struct p9_fid *dfid, *ofid, *fid;
497 	struct inode *inode;
498 
499 	P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
500 
501 	err = 0;
502 	ofid = NULL;
503 	fid = NULL;
504 	name = (char *) dentry->d_name.name;
505 	dfid = v9fs_fid_lookup(dentry->d_parent);
506 	if (IS_ERR(dfid)) {
507 		err = PTR_ERR(dfid);
508 		P9_DPRINTK(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
509 		return ERR_PTR(err);
510 	}
511 
512 	/* clone a fid to use for creation */
513 	ofid = p9_client_walk(dfid, 0, NULL, 1);
514 	if (IS_ERR(ofid)) {
515 		err = PTR_ERR(ofid);
516 		P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
517 		return ERR_PTR(err);
518 	}
519 
520 	err = p9_client_fcreate(ofid, name, perm, mode, extension);
521 	if (err < 0) {
522 		P9_DPRINTK(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
523 		goto error;
524 	}
525 
526 	/* now walk from the parent so we can get unopened fid */
527 	fid = p9_client_walk(dfid, 1, &name, 1);
528 	if (IS_ERR(fid)) {
529 		err = PTR_ERR(fid);
530 		P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
531 		fid = NULL;
532 		goto error;
533 	}
534 
535 	/* instantiate inode and assign the unopened fid to the dentry */
536 	inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
537 	if (IS_ERR(inode)) {
538 		err = PTR_ERR(inode);
539 		P9_DPRINTK(P9_DEBUG_VFS, "inode creation failed %d\n", err);
540 		goto error;
541 	}
542 
543 	if (v9ses->cache)
544 		dentry->d_op = &v9fs_cached_dentry_operations;
545 	else
546 		dentry->d_op = &v9fs_dentry_operations;
547 
548 	d_instantiate(dentry, inode);
549 	err = v9fs_fid_add(dentry, fid);
550 	if (err < 0)
551 		goto error;
552 
553 	return ofid;
554 
555 error:
556 	if (ofid)
557 		p9_client_clunk(ofid);
558 
559 	if (fid)
560 		p9_client_clunk(fid);
561 
562 	return ERR_PTR(err);
563 }
564 
565 /**
566  * v9fs_vfs_create - VFS hook to create files
567  * @dir: directory inode that is being created
568  * @dentry:  dentry that is being deleted
569  * @mode: create permissions
570  * @nd: path information
571  *
572  */
573 
574 static int
575 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
576 		struct nameidata *nd)
577 {
578 	int err;
579 	u32 perm;
580 	int flags;
581 	struct v9fs_session_info *v9ses;
582 	struct p9_fid *fid;
583 	struct file *filp;
584 
585 	err = 0;
586 	fid = NULL;
587 	v9ses = v9fs_inode2v9ses(dir);
588 	perm = unixmode2p9mode(v9ses, mode);
589 	if (nd && nd->flags & LOOKUP_OPEN)
590 		flags = nd->intent.open.flags - 1;
591 	else
592 		flags = O_RDWR;
593 
594 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
595 				v9fs_uflags2omode(flags,
596 						v9fs_proto_dotu(v9ses)));
597 	if (IS_ERR(fid)) {
598 		err = PTR_ERR(fid);
599 		fid = NULL;
600 		goto error;
601 	}
602 
603 	/* if we are opening a file, assign the open fid to the file */
604 	if (nd && nd->flags & LOOKUP_OPEN) {
605 		filp = lookup_instantiate_filp(nd, dentry, v9fs_open_created);
606 		if (IS_ERR(filp)) {
607 			err = PTR_ERR(filp);
608 			goto error;
609 		}
610 
611 		filp->private_data = fid;
612 	} else
613 		p9_client_clunk(fid);
614 
615 	return 0;
616 
617 error:
618 	if (fid)
619 		p9_client_clunk(fid);
620 
621 	return err;
622 }
623 
624 /**
625  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
626  * @dir:  inode that is being unlinked
627  * @dentry: dentry that is being unlinked
628  * @mode: mode for new directory
629  *
630  */
631 
632 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
633 {
634 	int err;
635 	u32 perm;
636 	struct v9fs_session_info *v9ses;
637 	struct p9_fid *fid;
638 
639 	P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
640 	err = 0;
641 	v9ses = v9fs_inode2v9ses(dir);
642 	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
643 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
644 	if (IS_ERR(fid)) {
645 		err = PTR_ERR(fid);
646 		fid = NULL;
647 	}
648 
649 	if (fid)
650 		p9_client_clunk(fid);
651 
652 	return err;
653 }
654 
655 /**
656  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
657  * @dir:  inode that is being walked from
658  * @dentry: dentry that is being walked to?
659  * @nameidata: path data
660  *
661  */
662 
663 static struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
664 				      struct nameidata *nameidata)
665 {
666 	struct super_block *sb;
667 	struct v9fs_session_info *v9ses;
668 	struct p9_fid *dfid, *fid;
669 	struct inode *inode;
670 	char *name;
671 	int result = 0;
672 
673 	P9_DPRINTK(P9_DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
674 		dir, dentry->d_name.name, dentry, nameidata);
675 
676 	if (dentry->d_name.len > NAME_MAX)
677 		return ERR_PTR(-ENAMETOOLONG);
678 
679 	sb = dir->i_sb;
680 	v9ses = v9fs_inode2v9ses(dir);
681 	dfid = v9fs_fid_lookup(dentry->d_parent);
682 	if (IS_ERR(dfid))
683 		return ERR_CAST(dfid);
684 
685 	name = (char *) dentry->d_name.name;
686 	fid = p9_client_walk(dfid, 1, &name, 1);
687 	if (IS_ERR(fid)) {
688 		result = PTR_ERR(fid);
689 		if (result == -ENOENT) {
690 			inode = NULL;
691 			goto inst_out;
692 		}
693 
694 		return ERR_PTR(result);
695 	}
696 
697 	inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
698 	if (IS_ERR(inode)) {
699 		result = PTR_ERR(inode);
700 		inode = NULL;
701 		goto error;
702 	}
703 
704 	result = v9fs_fid_add(dentry, fid);
705 	if (result < 0)
706 		goto error;
707 
708 inst_out:
709 	if (v9ses->cache)
710 		dentry->d_op = &v9fs_cached_dentry_operations;
711 	else
712 		dentry->d_op = &v9fs_dentry_operations;
713 
714 	d_add(dentry, inode);
715 	return NULL;
716 
717 error:
718 	p9_client_clunk(fid);
719 
720 	return ERR_PTR(result);
721 }
722 
723 /**
724  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
725  * @i:  inode that is being unlinked
726  * @d: dentry that is being unlinked
727  *
728  */
729 
730 static int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
731 {
732 	return v9fs_remove(i, d, 0);
733 }
734 
735 /**
736  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
737  * @i:  inode that is being unlinked
738  * @d: dentry that is being unlinked
739  *
740  */
741 
742 static int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
743 {
744 	return v9fs_remove(i, d, 1);
745 }
746 
747 /**
748  * v9fs_vfs_rename - VFS hook to rename an inode
749  * @old_dir:  old dir inode
750  * @old_dentry: old dentry
751  * @new_dir: new dir inode
752  * @new_dentry: new dentry
753  *
754  */
755 
756 static int
757 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
758 		struct inode *new_dir, struct dentry *new_dentry)
759 {
760 	struct inode *old_inode;
761 	struct v9fs_session_info *v9ses;
762 	struct p9_fid *oldfid;
763 	struct p9_fid *olddirfid;
764 	struct p9_fid *newdirfid;
765 	struct p9_wstat wstat;
766 	int retval;
767 
768 	P9_DPRINTK(P9_DEBUG_VFS, "\n");
769 	retval = 0;
770 	old_inode = old_dentry->d_inode;
771 	v9ses = v9fs_inode2v9ses(old_inode);
772 	oldfid = v9fs_fid_lookup(old_dentry);
773 	if (IS_ERR(oldfid))
774 		return PTR_ERR(oldfid);
775 
776 	olddirfid = v9fs_fid_clone(old_dentry->d_parent);
777 	if (IS_ERR(olddirfid)) {
778 		retval = PTR_ERR(olddirfid);
779 		goto done;
780 	}
781 
782 	newdirfid = v9fs_fid_clone(new_dentry->d_parent);
783 	if (IS_ERR(newdirfid)) {
784 		retval = PTR_ERR(newdirfid);
785 		goto clunk_olddir;
786 	}
787 
788 	if (v9fs_proto_dotl(v9ses)) {
789 		retval = p9_client_rename(oldfid, newdirfid,
790 					(char *) new_dentry->d_name.name);
791 		if (retval != -ENOSYS)
792 			goto clunk_newdir;
793 	}
794 
795 	/* 9P can only handle file rename in the same directory */
796 	if (memcmp(&olddirfid->qid, &newdirfid->qid, sizeof(newdirfid->qid))) {
797 		P9_DPRINTK(P9_DEBUG_ERROR,
798 				"old dir and new dir are different\n");
799 		retval = -EXDEV;
800 		goto clunk_newdir;
801 	}
802 
803 	v9fs_blank_wstat(&wstat);
804 	wstat.muid = v9ses->uname;
805 	wstat.name = (char *) new_dentry->d_name.name;
806 	retval = p9_client_wstat(oldfid, &wstat);
807 
808 clunk_newdir:
809 	p9_client_clunk(newdirfid);
810 
811 clunk_olddir:
812 	p9_client_clunk(olddirfid);
813 
814 done:
815 	return retval;
816 }
817 
818 /**
819  * v9fs_vfs_getattr - retrieve file metadata
820  * @mnt: mount information
821  * @dentry: file to get attributes on
822  * @stat: metadata structure to populate
823  *
824  */
825 
826 static int
827 v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
828 		 struct kstat *stat)
829 {
830 	int err;
831 	struct v9fs_session_info *v9ses;
832 	struct p9_fid *fid;
833 	struct p9_wstat *st;
834 
835 	P9_DPRINTK(P9_DEBUG_VFS, "dentry: %p\n", dentry);
836 	err = -EPERM;
837 	v9ses = v9fs_inode2v9ses(dentry->d_inode);
838 	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
839 		return simple_getattr(mnt, dentry, stat);
840 
841 	fid = v9fs_fid_lookup(dentry);
842 	if (IS_ERR(fid))
843 		return PTR_ERR(fid);
844 
845 	st = p9_client_stat(fid);
846 	if (IS_ERR(st))
847 		return PTR_ERR(st);
848 
849 	v9fs_stat2inode(st, dentry->d_inode, dentry->d_inode->i_sb);
850 		generic_fillattr(dentry->d_inode, stat);
851 
852 	kfree(st);
853 	return 0;
854 }
855 
856 /**
857  * v9fs_vfs_setattr - set file metadata
858  * @dentry: file whose metadata to set
859  * @iattr: metadata assignment structure
860  *
861  */
862 
863 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
864 {
865 	int retval;
866 	struct v9fs_session_info *v9ses;
867 	struct p9_fid *fid;
868 	struct p9_wstat wstat;
869 
870 	P9_DPRINTK(P9_DEBUG_VFS, "\n");
871 	retval = -EPERM;
872 	v9ses = v9fs_inode2v9ses(dentry->d_inode);
873 	fid = v9fs_fid_lookup(dentry);
874 	if(IS_ERR(fid))
875 		return PTR_ERR(fid);
876 
877 	v9fs_blank_wstat(&wstat);
878 	if (iattr->ia_valid & ATTR_MODE)
879 		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
880 
881 	if (iattr->ia_valid & ATTR_MTIME)
882 		wstat.mtime = iattr->ia_mtime.tv_sec;
883 
884 	if (iattr->ia_valid & ATTR_ATIME)
885 		wstat.atime = iattr->ia_atime.tv_sec;
886 
887 	if (iattr->ia_valid & ATTR_SIZE)
888 		wstat.length = iattr->ia_size;
889 
890 	if (v9fs_proto_dotu(v9ses)) {
891 		if (iattr->ia_valid & ATTR_UID)
892 			wstat.n_uid = iattr->ia_uid;
893 
894 		if (iattr->ia_valid & ATTR_GID)
895 			wstat.n_gid = iattr->ia_gid;
896 	}
897 
898 	retval = p9_client_wstat(fid, &wstat);
899 	if (retval >= 0)
900 		retval = inode_setattr(dentry->d_inode, iattr);
901 
902 	return retval;
903 }
904 
905 /**
906  * v9fs_stat2inode - populate an inode structure with mistat info
907  * @stat: Plan 9 metadata (mistat) structure
908  * @inode: inode to populate
909  * @sb: superblock of filesystem
910  *
911  */
912 
913 void
914 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
915 	struct super_block *sb)
916 {
917 	char ext[32];
918 	char tag_name[14];
919 	unsigned int i_nlink;
920 	struct v9fs_session_info *v9ses = sb->s_fs_info;
921 
922 	inode->i_nlink = 1;
923 
924 	inode->i_atime.tv_sec = stat->atime;
925 	inode->i_mtime.tv_sec = stat->mtime;
926 	inode->i_ctime.tv_sec = stat->mtime;
927 
928 	inode->i_uid = v9ses->dfltuid;
929 	inode->i_gid = v9ses->dfltgid;
930 
931 	if (v9fs_proto_dotu(v9ses)) {
932 		inode->i_uid = stat->n_uid;
933 		inode->i_gid = stat->n_gid;
934 	}
935 	if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
936 		if (v9fs_proto_dotu(v9ses) && (stat->extension[0] != '\0')) {
937 			/*
938 			 * Hadlink support got added later to
939 			 * to the .u extension. So there can be
940 			 * server out there that doesn't support
941 			 * this even with .u extension. So check
942 			 * for non NULL stat->extension
943 			 */
944 			strncpy(ext, stat->extension, sizeof(ext));
945 			/* HARDLINKCOUNT %u */
946 			sscanf(ext, "%13s %u", tag_name, &i_nlink);
947 			if (!strncmp(tag_name, "HARDLINKCOUNT", 13))
948 				inode->i_nlink = i_nlink;
949 		}
950 	}
951 	inode->i_mode = p9mode2unixmode(v9ses, stat->mode);
952 	if ((S_ISBLK(inode->i_mode)) || (S_ISCHR(inode->i_mode))) {
953 		char type = 0;
954 		int major = -1;
955 		int minor = -1;
956 
957 		strncpy(ext, stat->extension, sizeof(ext));
958 		sscanf(ext, "%c %u %u", &type, &major, &minor);
959 		switch (type) {
960 		case 'c':
961 			inode->i_mode &= ~S_IFBLK;
962 			inode->i_mode |= S_IFCHR;
963 			break;
964 		case 'b':
965 			break;
966 		default:
967 			P9_DPRINTK(P9_DEBUG_ERROR,
968 				"Unknown special type %c %s\n", type,
969 				stat->extension);
970 		};
971 		inode->i_rdev = MKDEV(major, minor);
972 		init_special_inode(inode, inode->i_mode, inode->i_rdev);
973 	} else
974 		inode->i_rdev = 0;
975 
976 	i_size_write(inode, stat->length);
977 
978 	/* not real number of blocks, but 512 byte ones ... */
979 	inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
980 }
981 
982 /**
983  * v9fs_qid2ino - convert qid into inode number
984  * @qid: qid to hash
985  *
986  * BUG: potential for inode number collisions?
987  */
988 
989 ino_t v9fs_qid2ino(struct p9_qid *qid)
990 {
991 	u64 path = qid->path + 2;
992 	ino_t i = 0;
993 
994 	if (sizeof(ino_t) == sizeof(path))
995 		memcpy(&i, &path, sizeof(ino_t));
996 	else
997 		i = (ino_t) (path ^ (path >> 32));
998 
999 	return i;
1000 }
1001 
1002 /**
1003  * v9fs_readlink - read a symlink's location (internal version)
1004  * @dentry: dentry for symlink
1005  * @buffer: buffer to load symlink location into
1006  * @buflen: length of buffer
1007  *
1008  */
1009 
1010 static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
1011 {
1012 	int retval;
1013 
1014 	struct v9fs_session_info *v9ses;
1015 	struct p9_fid *fid;
1016 	struct p9_wstat *st;
1017 
1018 	P9_DPRINTK(P9_DEBUG_VFS, " %s\n", dentry->d_name.name);
1019 	retval = -EPERM;
1020 	v9ses = v9fs_inode2v9ses(dentry->d_inode);
1021 	fid = v9fs_fid_lookup(dentry);
1022 	if (IS_ERR(fid))
1023 		return PTR_ERR(fid);
1024 
1025 	if (!v9fs_proto_dotu(v9ses))
1026 		return -EBADF;
1027 
1028 	st = p9_client_stat(fid);
1029 	if (IS_ERR(st))
1030 		return PTR_ERR(st);
1031 
1032 	if (!(st->mode & P9_DMSYMLINK)) {
1033 		retval = -EINVAL;
1034 		goto done;
1035 	}
1036 
1037 	/* copy extension buffer into buffer */
1038 	strncpy(buffer, st->extension, buflen);
1039 
1040 	P9_DPRINTK(P9_DEBUG_VFS,
1041 		"%s -> %s (%s)\n", dentry->d_name.name, st->extension, buffer);
1042 
1043 	retval = strnlen(buffer, buflen);
1044 done:
1045 	kfree(st);
1046 	return retval;
1047 }
1048 
1049 /**
1050  * v9fs_vfs_follow_link - follow a symlink path
1051  * @dentry: dentry for symlink
1052  * @nd: nameidata
1053  *
1054  */
1055 
1056 static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
1057 {
1058 	int len = 0;
1059 	char *link = __getname();
1060 
1061 	P9_DPRINTK(P9_DEBUG_VFS, "%s n", dentry->d_name.name);
1062 
1063 	if (!link)
1064 		link = ERR_PTR(-ENOMEM);
1065 	else {
1066 		len = v9fs_readlink(dentry, link, PATH_MAX);
1067 
1068 		if (len < 0) {
1069 			__putname(link);
1070 			link = ERR_PTR(len);
1071 		} else
1072 			link[min(len, PATH_MAX-1)] = 0;
1073 	}
1074 	nd_set_link(nd, link);
1075 
1076 	return NULL;
1077 }
1078 
1079 /**
1080  * v9fs_vfs_put_link - release a symlink path
1081  * @dentry: dentry for symlink
1082  * @nd: nameidata
1083  * @p: unused
1084  *
1085  */
1086 
1087 static void
1088 v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
1089 {
1090 	char *s = nd_get_link(nd);
1091 
1092 	P9_DPRINTK(P9_DEBUG_VFS, " %s %s\n", dentry->d_name.name,
1093 		IS_ERR(s) ? "<error>" : s);
1094 	if (!IS_ERR(s))
1095 		__putname(s);
1096 }
1097 
1098 /**
1099  * v9fs_vfs_mkspecial - create a special file
1100  * @dir: inode to create special file in
1101  * @dentry: dentry to create
1102  * @mode: mode to create special file
1103  * @extension: 9p2000.u format extension string representing special file
1104  *
1105  */
1106 
1107 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1108 	int mode, const char *extension)
1109 {
1110 	u32 perm;
1111 	struct v9fs_session_info *v9ses;
1112 	struct p9_fid *fid;
1113 
1114 	v9ses = v9fs_inode2v9ses(dir);
1115 	if (!v9fs_proto_dotu(v9ses)) {
1116 		P9_DPRINTK(P9_DEBUG_ERROR, "not extended\n");
1117 		return -EPERM;
1118 	}
1119 
1120 	perm = unixmode2p9mode(v9ses, mode);
1121 	fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1122 								P9_OREAD);
1123 	if (IS_ERR(fid))
1124 		return PTR_ERR(fid);
1125 
1126 	p9_client_clunk(fid);
1127 	return 0;
1128 }
1129 
1130 /**
1131  * v9fs_vfs_symlink - helper function to create symlinks
1132  * @dir: directory inode containing symlink
1133  * @dentry: dentry for symlink
1134  * @symname: symlink data
1135  *
1136  * See Also: 9P2000.u RFC for more information
1137  *
1138  */
1139 
1140 static int
1141 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1142 {
1143 	P9_DPRINTK(P9_DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino,
1144 					dentry->d_name.name, symname);
1145 
1146 	return v9fs_vfs_mkspecial(dir, dentry, S_IFLNK, symname);
1147 }
1148 
1149 /**
1150  * v9fs_vfs_link - create a hardlink
1151  * @old_dentry: dentry for file to link to
1152  * @dir: inode destination for new link
1153  * @dentry: dentry for link
1154  *
1155  */
1156 
1157 static int
1158 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1159 	      struct dentry *dentry)
1160 {
1161 	int retval;
1162 	struct p9_fid *oldfid;
1163 	char *name;
1164 
1165 	P9_DPRINTK(P9_DEBUG_VFS,
1166 		" %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
1167 		old_dentry->d_name.name);
1168 
1169 	oldfid = v9fs_fid_clone(old_dentry);
1170 	if (IS_ERR(oldfid))
1171 		return PTR_ERR(oldfid);
1172 
1173 	name = __getname();
1174 	if (unlikely(!name)) {
1175 		retval = -ENOMEM;
1176 		goto clunk_fid;
1177 	}
1178 
1179 	sprintf(name, "%d\n", oldfid->fid);
1180 	retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1181 	__putname(name);
1182 
1183 clunk_fid:
1184 	p9_client_clunk(oldfid);
1185 	return retval;
1186 }
1187 
1188 /**
1189  * v9fs_vfs_mknod - create a special file
1190  * @dir: inode destination for new link
1191  * @dentry: dentry for file
1192  * @mode: mode for creation
1193  * @rdev: device associated with special file
1194  *
1195  */
1196 
1197 static int
1198 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
1199 {
1200 	int retval;
1201 	char *name;
1202 
1203 	P9_DPRINTK(P9_DEBUG_VFS,
1204 		" %lu,%s mode: %x MAJOR: %u MINOR: %u\n", dir->i_ino,
1205 		dentry->d_name.name, mode, MAJOR(rdev), MINOR(rdev));
1206 
1207 	if (!new_valid_dev(rdev))
1208 		return -EINVAL;
1209 
1210 	name = __getname();
1211 	if (!name)
1212 		return -ENOMEM;
1213 	/* build extension */
1214 	if (S_ISBLK(mode))
1215 		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1216 	else if (S_ISCHR(mode))
1217 		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1218 	else if (S_ISFIFO(mode))
1219 		*name = 0;
1220 	else if (S_ISSOCK(mode))
1221 		*name = 0;
1222 	else {
1223 		__putname(name);
1224 		return -EINVAL;
1225 	}
1226 
1227 	retval = v9fs_vfs_mkspecial(dir, dentry, mode, name);
1228 	__putname(name);
1229 
1230 	return retval;
1231 }
1232 
1233 static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1234 	.create = v9fs_vfs_create,
1235 	.lookup = v9fs_vfs_lookup,
1236 	.symlink = v9fs_vfs_symlink,
1237 	.link = v9fs_vfs_link,
1238 	.unlink = v9fs_vfs_unlink,
1239 	.mkdir = v9fs_vfs_mkdir,
1240 	.rmdir = v9fs_vfs_rmdir,
1241 	.mknod = v9fs_vfs_mknod,
1242 	.rename = v9fs_vfs_rename,
1243 	.getattr = v9fs_vfs_getattr,
1244 	.setattr = v9fs_vfs_setattr,
1245 };
1246 
1247 static const struct inode_operations v9fs_dir_inode_operations_dotl = {
1248 	.create = v9fs_vfs_create,
1249 	.lookup = v9fs_vfs_lookup,
1250 	.symlink = v9fs_vfs_symlink,
1251 	.link = v9fs_vfs_link,
1252 	.unlink = v9fs_vfs_unlink,
1253 	.mkdir = v9fs_vfs_mkdir,
1254 	.rmdir = v9fs_vfs_rmdir,
1255 	.mknod = v9fs_vfs_mknod,
1256 	.rename = v9fs_vfs_rename,
1257 	.getattr = v9fs_vfs_getattr,
1258 	.setattr = v9fs_vfs_setattr,
1259 };
1260 
1261 static const struct inode_operations v9fs_dir_inode_operations = {
1262 	.create = v9fs_vfs_create,
1263 	.lookup = v9fs_vfs_lookup,
1264 	.unlink = v9fs_vfs_unlink,
1265 	.mkdir = v9fs_vfs_mkdir,
1266 	.rmdir = v9fs_vfs_rmdir,
1267 	.mknod = v9fs_vfs_mknod,
1268 	.rename = v9fs_vfs_rename,
1269 	.getattr = v9fs_vfs_getattr,
1270 	.setattr = v9fs_vfs_setattr,
1271 };
1272 
1273 static const struct inode_operations v9fs_file_inode_operations = {
1274 	.getattr = v9fs_vfs_getattr,
1275 	.setattr = v9fs_vfs_setattr,
1276 };
1277 
1278 static const struct inode_operations v9fs_file_inode_operations_dotl = {
1279 	.getattr = v9fs_vfs_getattr,
1280 	.setattr = v9fs_vfs_setattr,
1281 };
1282 
1283 static const struct inode_operations v9fs_symlink_inode_operations = {
1284 	.readlink = generic_readlink,
1285 	.follow_link = v9fs_vfs_follow_link,
1286 	.put_link = v9fs_vfs_put_link,
1287 	.getattr = v9fs_vfs_getattr,
1288 	.setattr = v9fs_vfs_setattr,
1289 };
1290 
1291 static const struct inode_operations v9fs_symlink_inode_operations_dotl = {
1292 	.readlink = generic_readlink,
1293 	.follow_link = v9fs_vfs_follow_link,
1294 	.put_link = v9fs_vfs_put_link,
1295 	.getattr = v9fs_vfs_getattr,
1296 	.setattr = v9fs_vfs_setattr,
1297 };
1298