xref: /openbmc/linux/fs/9p/vfs_inode.c (revision 732a675a)
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 <net/9p/9p.h>
38 #include <net/9p/client.h>
39 
40 #include "v9fs.h"
41 #include "v9fs_vfs.h"
42 #include "fid.h"
43 
44 static const struct inode_operations v9fs_dir_inode_operations;
45 static const struct inode_operations v9fs_dir_inode_operations_ext;
46 static const struct inode_operations v9fs_file_inode_operations;
47 static const struct inode_operations v9fs_symlink_inode_operations;
48 
49 /**
50  * unixmode2p9mode - convert unix mode bits to plan 9
51  * @v9ses: v9fs session information
52  * @mode: mode to convert
53  *
54  */
55 
56 static int unixmode2p9mode(struct v9fs_session_info *v9ses, int mode)
57 {
58 	int res;
59 	res = mode & 0777;
60 	if (S_ISDIR(mode))
61 		res |= P9_DMDIR;
62 	if (v9fs_extended(v9ses)) {
63 		if (S_ISLNK(mode))
64 			res |= P9_DMSYMLINK;
65 		if (v9ses->nodev == 0) {
66 			if (S_ISSOCK(mode))
67 				res |= P9_DMSOCKET;
68 			if (S_ISFIFO(mode))
69 				res |= P9_DMNAMEDPIPE;
70 			if (S_ISBLK(mode))
71 				res |= P9_DMDEVICE;
72 			if (S_ISCHR(mode))
73 				res |= P9_DMDEVICE;
74 		}
75 
76 		if ((mode & S_ISUID) == S_ISUID)
77 			res |= P9_DMSETUID;
78 		if ((mode & S_ISGID) == S_ISGID)
79 			res |= P9_DMSETGID;
80 		if ((mode & S_ISVTX) == S_ISVTX)
81 			res |= P9_DMSETVTX;
82 		if ((mode & P9_DMLINK))
83 			res |= P9_DMLINK;
84 	}
85 
86 	return res;
87 }
88 
89 /**
90  * p9mode2unixmode- convert plan9 mode bits to unix mode bits
91  * @v9ses: v9fs session information
92  * @mode: mode to convert
93  *
94  */
95 
96 static int p9mode2unixmode(struct v9fs_session_info *v9ses, int mode)
97 {
98 	int res;
99 
100 	res = mode & 0777;
101 
102 	if ((mode & P9_DMDIR) == P9_DMDIR)
103 		res |= S_IFDIR;
104 	else if ((mode & P9_DMSYMLINK) && (v9fs_extended(v9ses)))
105 		res |= S_IFLNK;
106 	else if ((mode & P9_DMSOCKET) && (v9fs_extended(v9ses))
107 		 && (v9ses->nodev == 0))
108 		res |= S_IFSOCK;
109 	else if ((mode & P9_DMNAMEDPIPE) && (v9fs_extended(v9ses))
110 		 && (v9ses->nodev == 0))
111 		res |= S_IFIFO;
112 	else if ((mode & P9_DMDEVICE) && (v9fs_extended(v9ses))
113 		 && (v9ses->nodev == 0))
114 		res |= S_IFBLK;
115 	else
116 		res |= S_IFREG;
117 
118 	if (v9fs_extended(v9ses)) {
119 		if ((mode & P9_DMSETUID) == P9_DMSETUID)
120 			res |= S_ISUID;
121 
122 		if ((mode & P9_DMSETGID) == P9_DMSETGID)
123 			res |= S_ISGID;
124 
125 		if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
126 			res |= S_ISVTX;
127 	}
128 
129 	return res;
130 }
131 
132 /**
133  * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
134  * @uflags: flags to convert
135  *
136  */
137 
138 int v9fs_uflags2omode(int uflags)
139 {
140 	int ret;
141 
142 	ret = 0;
143 	switch (uflags&3) {
144 	default:
145 	case O_RDONLY:
146 		ret = P9_OREAD;
147 		break;
148 
149 	case O_WRONLY:
150 		ret = P9_OWRITE;
151 		break;
152 
153 	case O_RDWR:
154 		ret = P9_ORDWR;
155 		break;
156 	}
157 
158 	if (uflags & O_EXCL)
159 		ret |= P9_OEXCL;
160 
161 	if (uflags & O_TRUNC)
162 		ret |= P9_OTRUNC;
163 
164 	if (uflags & O_APPEND)
165 		ret |= P9_OAPPEND;
166 
167 	return ret;
168 }
169 
170 /**
171  * v9fs_blank_wstat - helper function to setup a 9P stat structure
172  * @v9ses: 9P session info (for determining extended mode)
173  * @wstat: structure to initialize
174  *
175  */
176 
177 static void
178 v9fs_blank_wstat(struct p9_wstat *wstat)
179 {
180 	wstat->type = ~0;
181 	wstat->dev = ~0;
182 	wstat->qid.type = ~0;
183 	wstat->qid.version = ~0;
184 	*((long long *)&wstat->qid.path) = ~0;
185 	wstat->mode = ~0;
186 	wstat->atime = ~0;
187 	wstat->mtime = ~0;
188 	wstat->length = ~0;
189 	wstat->name = NULL;
190 	wstat->uid = NULL;
191 	wstat->gid = NULL;
192 	wstat->muid = NULL;
193 	wstat->n_uid = ~0;
194 	wstat->n_gid = ~0;
195 	wstat->n_muid = ~0;
196 	wstat->extension = NULL;
197 }
198 
199 /**
200  * v9fs_get_inode - helper function to setup an inode
201  * @sb: superblock
202  * @mode: mode to setup inode with
203  *
204  */
205 
206 struct inode *v9fs_get_inode(struct super_block *sb, int mode)
207 {
208 	struct inode *inode;
209 	struct v9fs_session_info *v9ses = sb->s_fs_info;
210 
211 	P9_DPRINTK(P9_DEBUG_VFS, "super block: %p mode: %o\n", sb, mode);
212 
213 	inode = new_inode(sb);
214 	if (inode) {
215 		inode->i_mode = mode;
216 		inode->i_uid = current->fsuid;
217 		inode->i_gid = current->fsgid;
218 		inode->i_blocks = 0;
219 		inode->i_rdev = 0;
220 		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
221 		inode->i_mapping->a_ops = &v9fs_addr_operations;
222 
223 		switch (mode & S_IFMT) {
224 		case S_IFIFO:
225 		case S_IFBLK:
226 		case S_IFCHR:
227 		case S_IFSOCK:
228 			if (!v9fs_extended(v9ses)) {
229 				P9_DPRINTK(P9_DEBUG_ERROR,
230 				      "special files without extended mode\n");
231 				return ERR_PTR(-EINVAL);
232 			}
233 			init_special_inode(inode, inode->i_mode,
234 					   inode->i_rdev);
235 			break;
236 		case S_IFREG:
237 			inode->i_op = &v9fs_file_inode_operations;
238 			inode->i_fop = &v9fs_file_operations;
239 			break;
240 		case S_IFLNK:
241 			if (!v9fs_extended(v9ses)) {
242 				P9_DPRINTK(P9_DEBUG_ERROR,
243 					"extended modes used w/o 9P2000.u\n");
244 				return ERR_PTR(-EINVAL);
245 			}
246 			inode->i_op = &v9fs_symlink_inode_operations;
247 			break;
248 		case S_IFDIR:
249 			inc_nlink(inode);
250 			if (v9fs_extended(v9ses))
251 				inode->i_op = &v9fs_dir_inode_operations_ext;
252 			else
253 				inode->i_op = &v9fs_dir_inode_operations;
254 			inode->i_fop = &v9fs_dir_operations;
255 			break;
256 		default:
257 			P9_DPRINTK(P9_DEBUG_ERROR,
258 				"BAD mode 0x%x S_IFMT 0x%x\n",
259 				mode, mode & S_IFMT);
260 			return ERR_PTR(-EINVAL);
261 		}
262 	} else {
263 		P9_EPRINTK(KERN_WARNING, "Problem allocating inode\n");
264 		return ERR_PTR(-ENOMEM);
265 	}
266 	return inode;
267 }
268 
269 /*
270 static struct v9fs_fid*
271 v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
272 {
273 	int err;
274 	int nfid;
275 	struct v9fs_fid *ret;
276 	struct v9fs_fcall *fcall;
277 
278 	nfid = v9fs_get_idpool(&v9ses->fidpool);
279 	if (nfid < 0) {
280 		eprintk(KERN_WARNING, "no free fids available\n");
281 		return ERR_PTR(-ENOSPC);
282 	}
283 
284 	err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
285 		&fcall);
286 
287 	if (err < 0) {
288 		if (fcall && fcall->id == RWALK)
289 			goto clunk_fid;
290 
291 		PRINT_FCALL_ERROR("walk error", fcall);
292 		v9fs_put_idpool(nfid, &v9ses->fidpool);
293 		goto error;
294 	}
295 
296 	kfree(fcall);
297 	fcall = NULL;
298 	ret = v9fs_fid_create(v9ses, nfid);
299 	if (!ret) {
300 		err = -ENOMEM;
301 		goto clunk_fid;
302 	}
303 
304 	err = v9fs_fid_insert(ret, dentry);
305 	if (err < 0) {
306 		v9fs_fid_destroy(ret);
307 		goto clunk_fid;
308 	}
309 
310 	return ret;
311 
312 clunk_fid:
313 	v9fs_t_clunk(v9ses, nfid);
314 
315 error:
316 	kfree(fcall);
317 	return ERR_PTR(err);
318 }
319 */
320 
321 /**
322  * v9fs_inode_from_fid - populate an inode by issuing a attribute request
323  * @v9ses: session information
324  * @fid: fid to issue attribute request for
325  * @sb: superblock on which to create inode
326  *
327  */
328 
329 static struct inode *
330 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
331 	struct super_block *sb)
332 {
333 	int err, umode;
334 	struct inode *ret;
335 	struct p9_stat *st;
336 
337 	ret = NULL;
338 	st = p9_client_stat(fid);
339 	if (IS_ERR(st)) {
340 		err = PTR_ERR(st);
341 		st = NULL;
342 		goto error;
343 	}
344 
345 	umode = p9mode2unixmode(v9ses, st->mode);
346 	ret = v9fs_get_inode(sb, umode);
347 	if (IS_ERR(ret)) {
348 		err = PTR_ERR(ret);
349 		ret = NULL;
350 		goto error;
351 	}
352 
353 	v9fs_stat2inode(st, ret, sb);
354 	ret->i_ino = v9fs_qid2ino(&st->qid);
355 	kfree(st);
356 	return ret;
357 
358 error:
359 	kfree(st);
360 	if (ret)
361 		iput(ret);
362 
363 	return ERR_PTR(err);
364 }
365 
366 /**
367  * v9fs_remove - helper function to remove files and directories
368  * @dir: directory inode that is being deleted
369  * @file:  dentry that is being deleted
370  * @rmdir: removing a directory
371  *
372  */
373 
374 static int v9fs_remove(struct inode *dir, struct dentry *file, int rmdir)
375 {
376 	struct inode *file_inode;
377 	struct v9fs_session_info *v9ses;
378 	struct p9_fid *v9fid;
379 
380 	P9_DPRINTK(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %d\n", dir, file,
381 		rmdir);
382 
383 	file_inode = file->d_inode;
384 	v9ses = v9fs_inode2v9ses(file_inode);
385 	v9fid = v9fs_fid_clone(file);
386 	if (IS_ERR(v9fid))
387 		return PTR_ERR(v9fid);
388 
389 	return p9_client_remove(v9fid);
390 }
391 
392 static int
393 v9fs_open_created(struct inode *inode, struct file *file)
394 {
395 	return 0;
396 }
397 
398 
399 /**
400  * v9fs_create - Create a file
401  * @v9ses: session information
402  * @dir: directory that dentry is being created in
403  * @dentry:  dentry that is being created
404  * @perm: create permissions
405  * @mode: open mode
406  * @extension: 9p2000.u extension string to support devices, etc.
407  *
408  */
409 static struct p9_fid *
410 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
411 		struct dentry *dentry, char *extension, u32 perm, u8 mode)
412 {
413 	int err;
414 	char *name;
415 	struct p9_fid *dfid, *ofid, *fid;
416 	struct inode *inode;
417 
418 	err = 0;
419 	ofid = NULL;
420 	fid = NULL;
421 	name = (char *) dentry->d_name.name;
422 	dfid = v9fs_fid_clone(dentry->d_parent);
423 	if (IS_ERR(dfid)) {
424 		err = PTR_ERR(dfid);
425 		dfid = NULL;
426 		goto error;
427 	}
428 
429 	/* clone a fid to use for creation */
430 	ofid = p9_client_walk(dfid, 0, NULL, 1);
431 	if (IS_ERR(ofid)) {
432 		err = PTR_ERR(ofid);
433 		ofid = NULL;
434 		goto error;
435 	}
436 
437 	err = p9_client_fcreate(ofid, name, perm, mode, extension);
438 	if (err < 0)
439 		goto error;
440 
441 	/* now walk from the parent so we can get unopened fid */
442 	fid = p9_client_walk(dfid, 1, &name, 0);
443 	if (IS_ERR(fid)) {
444 		err = PTR_ERR(fid);
445 		fid = NULL;
446 		goto error;
447 	} else
448 		dfid = NULL;
449 
450 	/* instantiate inode and assign the unopened fid to the dentry */
451 	inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
452 	if (IS_ERR(inode)) {
453 		err = PTR_ERR(inode);
454 		goto error;
455 	}
456 
457 	if (v9ses->cache)
458 		dentry->d_op = &v9fs_cached_dentry_operations;
459 	else
460 		dentry->d_op = &v9fs_dentry_operations;
461 
462 	d_instantiate(dentry, inode);
463 	v9fs_fid_add(dentry, fid);
464 	return ofid;
465 
466 error:
467 	if (dfid)
468 		p9_client_clunk(dfid);
469 
470 	if (ofid)
471 		p9_client_clunk(ofid);
472 
473 	if (fid)
474 		p9_client_clunk(fid);
475 
476 	return ERR_PTR(err);
477 }
478 
479 /**
480  * v9fs_vfs_create - VFS hook to create files
481  * @dir: directory inode that is being created
482  * @dentry:  dentry that is being deleted
483  * @mode: create permissions
484  * @nd: path information
485  *
486  */
487 
488 static int
489 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
490 		struct nameidata *nd)
491 {
492 	int err;
493 	u32 perm;
494 	int flags;
495 	struct v9fs_session_info *v9ses;
496 	struct p9_fid *fid;
497 	struct file *filp;
498 
499 	err = 0;
500 	fid = NULL;
501 	v9ses = v9fs_inode2v9ses(dir);
502 	perm = unixmode2p9mode(v9ses, mode);
503 	if (nd && nd->flags & LOOKUP_OPEN)
504 		flags = nd->intent.open.flags - 1;
505 	else
506 		flags = O_RDWR;
507 
508 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
509 						v9fs_uflags2omode(flags));
510 	if (IS_ERR(fid)) {
511 		err = PTR_ERR(fid);
512 		fid = NULL;
513 		goto error;
514 	}
515 
516 	/* if we are opening a file, assign the open fid to the file */
517 	if (nd && nd->flags & LOOKUP_OPEN) {
518 		filp = lookup_instantiate_filp(nd, dentry, v9fs_open_created);
519 		if (IS_ERR(filp)) {
520 			err = PTR_ERR(filp);
521 			goto error;
522 		}
523 
524 		filp->private_data = fid;
525 	} else
526 		p9_client_clunk(fid);
527 
528 	return 0;
529 
530 error:
531 	if (fid)
532 		p9_client_clunk(fid);
533 
534 	return err;
535 }
536 
537 /**
538  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
539  * @dir:  inode that is being unlinked
540  * @dentry: dentry that is being unlinked
541  * @mode: mode for new directory
542  *
543  */
544 
545 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
546 {
547 	int err;
548 	u32 perm;
549 	struct v9fs_session_info *v9ses;
550 	struct p9_fid *fid;
551 
552 	P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
553 	err = 0;
554 	v9ses = v9fs_inode2v9ses(dir);
555 	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
556 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
557 	if (IS_ERR(fid)) {
558 		err = PTR_ERR(fid);
559 		fid = NULL;
560 	}
561 
562 	if (fid)
563 		p9_client_clunk(fid);
564 
565 	return err;
566 }
567 
568 /**
569  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
570  * @dir:  inode that is being walked from
571  * @dentry: dentry that is being walked to?
572  * @nameidata: path data
573  *
574  */
575 
576 static struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
577 				      struct nameidata *nameidata)
578 {
579 	struct super_block *sb;
580 	struct v9fs_session_info *v9ses;
581 	struct p9_fid *dfid, *fid;
582 	struct inode *inode;
583 	char *name;
584 	int result = 0;
585 
586 	P9_DPRINTK(P9_DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
587 		dir, dentry->d_name.name, dentry, nameidata);
588 
589 	sb = dir->i_sb;
590 	v9ses = v9fs_inode2v9ses(dir);
591 	dfid = v9fs_fid_lookup(dentry->d_parent);
592 	if (IS_ERR(dfid))
593 		return ERR_CAST(dfid);
594 
595 	name = (char *) dentry->d_name.name;
596 	fid = p9_client_walk(dfid, 1, &name, 1);
597 	if (IS_ERR(fid)) {
598 		result = PTR_ERR(fid);
599 		if (result == -ENOENT) {
600 			d_add(dentry, NULL);
601 			return NULL;
602 		}
603 
604 		return ERR_PTR(result);
605 	}
606 
607 	inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
608 	if (IS_ERR(inode)) {
609 		result = PTR_ERR(inode);
610 		inode = NULL;
611 		goto error;
612 	}
613 
614 	result = v9fs_fid_add(dentry, fid);
615 	if (result < 0)
616 		goto error;
617 
618 	if ((fid->qid.version) && (v9ses->cache))
619 		dentry->d_op = &v9fs_cached_dentry_operations;
620 	else
621 		dentry->d_op = &v9fs_dentry_operations;
622 
623 	d_add(dentry, inode);
624 	return NULL;
625 
626 error:
627 	if (fid)
628 		p9_client_clunk(fid);
629 
630 	return ERR_PTR(result);
631 }
632 
633 /**
634  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
635  * @i:  inode that is being unlinked
636  * @d: dentry that is being unlinked
637  *
638  */
639 
640 static int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
641 {
642 	return v9fs_remove(i, d, 0);
643 }
644 
645 /**
646  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
647  * @i:  inode that is being unlinked
648  * @d: dentry that is being unlinked
649  *
650  */
651 
652 static int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
653 {
654 	return v9fs_remove(i, d, 1);
655 }
656 
657 /**
658  * v9fs_vfs_rename - VFS hook to rename an inode
659  * @old_dir:  old dir inode
660  * @old_dentry: old dentry
661  * @new_dir: new dir inode
662  * @new_dentry: new dentry
663  *
664  */
665 
666 static int
667 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
668 		struct inode *new_dir, struct dentry *new_dentry)
669 {
670 	struct inode *old_inode;
671 	struct v9fs_session_info *v9ses;
672 	struct p9_fid *oldfid;
673 	struct p9_fid *olddirfid;
674 	struct p9_fid *newdirfid;
675 	struct p9_wstat wstat;
676 	int retval;
677 
678 	P9_DPRINTK(P9_DEBUG_VFS, "\n");
679 	retval = 0;
680 	old_inode = old_dentry->d_inode;
681 	v9ses = v9fs_inode2v9ses(old_inode);
682 	oldfid = v9fs_fid_lookup(old_dentry);
683 	if (IS_ERR(oldfid))
684 		return PTR_ERR(oldfid);
685 
686 	olddirfid = v9fs_fid_clone(old_dentry->d_parent);
687 	if (IS_ERR(olddirfid)) {
688 		retval = PTR_ERR(olddirfid);
689 		goto done;
690 	}
691 
692 	newdirfid = v9fs_fid_clone(new_dentry->d_parent);
693 	if (IS_ERR(newdirfid)) {
694 		retval = PTR_ERR(newdirfid);
695 		goto clunk_olddir;
696 	}
697 
698 	/* 9P can only handle file rename in the same directory */
699 	if (memcmp(&olddirfid->qid, &newdirfid->qid, sizeof(newdirfid->qid))) {
700 		P9_DPRINTK(P9_DEBUG_ERROR,
701 				"old dir and new dir are different\n");
702 		retval = -EXDEV;
703 		goto clunk_newdir;
704 	}
705 
706 	v9fs_blank_wstat(&wstat);
707 	wstat.muid = v9ses->uname;
708 	wstat.name = (char *) new_dentry->d_name.name;
709 	retval = p9_client_wstat(oldfid, &wstat);
710 
711 clunk_newdir:
712 	p9_client_clunk(newdirfid);
713 
714 clunk_olddir:
715 	p9_client_clunk(olddirfid);
716 
717 done:
718 	return retval;
719 }
720 
721 /**
722  * v9fs_vfs_getattr - retrieve file metadata
723  * @mnt: mount information
724  * @dentry: file to get attributes on
725  * @stat: metadata structure to populate
726  *
727  */
728 
729 static int
730 v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
731 		 struct kstat *stat)
732 {
733 	int err;
734 	struct v9fs_session_info *v9ses;
735 	struct p9_fid *fid;
736 	struct p9_stat *st;
737 
738 	P9_DPRINTK(P9_DEBUG_VFS, "dentry: %p\n", dentry);
739 	err = -EPERM;
740 	v9ses = v9fs_inode2v9ses(dentry->d_inode);
741 	if (v9ses->cache == CACHE_LOOSE)
742 		return simple_getattr(mnt, dentry, stat);
743 
744 	fid = v9fs_fid_lookup(dentry);
745 	if (IS_ERR(fid))
746 		return PTR_ERR(fid);
747 
748 	st = p9_client_stat(fid);
749 	if (IS_ERR(st))
750 		return PTR_ERR(st);
751 
752 	v9fs_stat2inode(st, dentry->d_inode, dentry->d_inode->i_sb);
753 		generic_fillattr(dentry->d_inode, stat);
754 
755 	kfree(st);
756 	return 0;
757 }
758 
759 /**
760  * v9fs_vfs_setattr - set file metadata
761  * @dentry: file whose metadata to set
762  * @iattr: metadata assignment structure
763  *
764  */
765 
766 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
767 {
768 	int retval;
769 	struct v9fs_session_info *v9ses;
770 	struct p9_fid *fid;
771 	struct p9_wstat wstat;
772 
773 	P9_DPRINTK(P9_DEBUG_VFS, "\n");
774 	retval = -EPERM;
775 	v9ses = v9fs_inode2v9ses(dentry->d_inode);
776 	fid = v9fs_fid_lookup(dentry);
777 	if(IS_ERR(fid))
778 		return PTR_ERR(fid);
779 
780 	v9fs_blank_wstat(&wstat);
781 	if (iattr->ia_valid & ATTR_MODE)
782 		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
783 
784 	if (iattr->ia_valid & ATTR_MTIME)
785 		wstat.mtime = iattr->ia_mtime.tv_sec;
786 
787 	if (iattr->ia_valid & ATTR_ATIME)
788 		wstat.atime = iattr->ia_atime.tv_sec;
789 
790 	if (iattr->ia_valid & ATTR_SIZE)
791 		wstat.length = iattr->ia_size;
792 
793 	if (v9fs_extended(v9ses)) {
794 		if (iattr->ia_valid & ATTR_UID)
795 			wstat.n_uid = iattr->ia_uid;
796 
797 		if (iattr->ia_valid & ATTR_GID)
798 			wstat.n_gid = iattr->ia_gid;
799 	}
800 
801 	retval = p9_client_wstat(fid, &wstat);
802 	if (retval >= 0)
803 		retval = inode_setattr(dentry->d_inode, iattr);
804 
805 	return retval;
806 }
807 
808 /**
809  * v9fs_stat2inode - populate an inode structure with mistat info
810  * @stat: Plan 9 metadata (mistat) structure
811  * @inode: inode to populate
812  * @sb: superblock of filesystem
813  *
814  */
815 
816 void
817 v9fs_stat2inode(struct p9_stat *stat, struct inode *inode,
818 	struct super_block *sb)
819 {
820 	int n;
821 	char ext[32];
822 	struct v9fs_session_info *v9ses = sb->s_fs_info;
823 
824 	inode->i_nlink = 1;
825 
826 	inode->i_atime.tv_sec = stat->atime;
827 	inode->i_mtime.tv_sec = stat->mtime;
828 	inode->i_ctime.tv_sec = stat->mtime;
829 
830 	inode->i_uid = v9ses->dfltuid;
831 	inode->i_gid = v9ses->dfltgid;
832 
833 	if (v9fs_extended(v9ses)) {
834 		inode->i_uid = stat->n_uid;
835 		inode->i_gid = stat->n_gid;
836 	}
837 
838 	inode->i_mode = p9mode2unixmode(v9ses, stat->mode);
839 	if ((S_ISBLK(inode->i_mode)) || (S_ISCHR(inode->i_mode))) {
840 		char type = 0;
841 		int major = -1;
842 		int minor = -1;
843 
844 		n = stat->extension.len;
845 		if (n > sizeof(ext)-1)
846 			n = sizeof(ext)-1;
847 		memmove(ext, stat->extension.str, n);
848 		ext[n] = 0;
849 		sscanf(ext, "%c %u %u", &type, &major, &minor);
850 		switch (type) {
851 		case 'c':
852 			inode->i_mode &= ~S_IFBLK;
853 			inode->i_mode |= S_IFCHR;
854 			break;
855 		case 'b':
856 			break;
857 		default:
858 			P9_DPRINTK(P9_DEBUG_ERROR,
859 				"Unknown special type %c (%.*s)\n", type,
860 				stat->extension.len, stat->extension.str);
861 		};
862 		inode->i_rdev = MKDEV(major, minor);
863 	} else
864 		inode->i_rdev = 0;
865 
866 	inode->i_size = stat->length;
867 
868 	/* not real number of blocks, but 512 byte ones ... */
869 	inode->i_blocks = (inode->i_size + 512 - 1) >> 9;
870 }
871 
872 /**
873  * v9fs_qid2ino - convert qid into inode number
874  * @qid: qid to hash
875  *
876  * BUG: potential for inode number collisions?
877  */
878 
879 ino_t v9fs_qid2ino(struct p9_qid *qid)
880 {
881 	u64 path = qid->path + 2;
882 	ino_t i = 0;
883 
884 	if (sizeof(ino_t) == sizeof(path))
885 		memcpy(&i, &path, sizeof(ino_t));
886 	else
887 		i = (ino_t) (path ^ (path >> 32));
888 
889 	return i;
890 }
891 
892 /**
893  * v9fs_readlink - read a symlink's location (internal version)
894  * @dentry: dentry for symlink
895  * @buffer: buffer to load symlink location into
896  * @buflen: length of buffer
897  *
898  */
899 
900 static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
901 {
902 	int retval;
903 
904 	struct v9fs_session_info *v9ses;
905 	struct p9_fid *fid;
906 	struct p9_stat *st;
907 
908 	P9_DPRINTK(P9_DEBUG_VFS, " %s\n", dentry->d_name.name);
909 	retval = -EPERM;
910 	v9ses = v9fs_inode2v9ses(dentry->d_inode);
911 	fid = v9fs_fid_lookup(dentry);
912 	if (IS_ERR(fid))
913 		return PTR_ERR(fid);
914 
915 	if (!v9fs_extended(v9ses))
916 		return -EBADF;
917 
918 	st = p9_client_stat(fid);
919 	if (IS_ERR(st))
920 		return PTR_ERR(st);
921 
922 	if (!(st->mode & P9_DMSYMLINK)) {
923 		retval = -EINVAL;
924 		goto done;
925 	}
926 
927 	/* copy extension buffer into buffer */
928 	if (st->extension.len < buflen)
929 		buflen = st->extension.len + 1;
930 
931 	memmove(buffer, st->extension.str, buflen - 1);
932 	buffer[buflen-1] = 0;
933 
934 	P9_DPRINTK(P9_DEBUG_VFS,
935 		"%s -> %.*s (%s)\n", dentry->d_name.name, st->extension.len,
936 		st->extension.str, buffer);
937 
938 	retval = buflen;
939 
940 done:
941 	kfree(st);
942 	return retval;
943 }
944 
945 /**
946  * v9fs_vfs_readlink - read a symlink's location
947  * @dentry: dentry for symlink
948  * @buffer: buffer to load symlink location into
949  * @buflen: length of buffer
950  *
951  */
952 
953 static int v9fs_vfs_readlink(struct dentry *dentry, char __user * buffer,
954 			     int buflen)
955 {
956 	int retval;
957 	int ret;
958 	char *link = __getname();
959 
960 	if (unlikely(!link))
961 		return -ENOMEM;
962 
963 	if (buflen > PATH_MAX)
964 		buflen = PATH_MAX;
965 
966 	P9_DPRINTK(P9_DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);
967 
968 	retval = v9fs_readlink(dentry, link, buflen);
969 
970 	if (retval > 0) {
971 		if ((ret = copy_to_user(buffer, link, retval)) != 0) {
972 			P9_DPRINTK(P9_DEBUG_ERROR,
973 					"problem copying to user: %d\n", ret);
974 			retval = ret;
975 		}
976 	}
977 
978 	__putname(link);
979 	return retval;
980 }
981 
982 /**
983  * v9fs_vfs_follow_link - follow a symlink path
984  * @dentry: dentry for symlink
985  * @nd: nameidata
986  *
987  */
988 
989 static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
990 {
991 	int len = 0;
992 	char *link = __getname();
993 
994 	P9_DPRINTK(P9_DEBUG_VFS, "%s n", dentry->d_name.name);
995 
996 	if (!link)
997 		link = ERR_PTR(-ENOMEM);
998 	else {
999 		len = v9fs_readlink(dentry, link, PATH_MAX);
1000 
1001 		if (len < 0) {
1002 			__putname(link);
1003 			link = ERR_PTR(len);
1004 		} else
1005 			link[len] = 0;
1006 	}
1007 	nd_set_link(nd, link);
1008 
1009 	return NULL;
1010 }
1011 
1012 /**
1013  * v9fs_vfs_put_link - release a symlink path
1014  * @dentry: dentry for symlink
1015  * @nd: nameidata
1016  * @p: unused
1017  *
1018  */
1019 
1020 static void
1021 v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
1022 {
1023 	char *s = nd_get_link(nd);
1024 
1025 	P9_DPRINTK(P9_DEBUG_VFS, " %s %s\n", dentry->d_name.name, s);
1026 	if (!IS_ERR(s))
1027 		__putname(s);
1028 }
1029 
1030 /**
1031  * v9fs_vfs_mkspecial - create a special file
1032  * @dir: inode to create special file in
1033  * @dentry: dentry to create
1034  * @mode: mode to create special file
1035  * @extension: 9p2000.u format extension string representing special file
1036  *
1037  */
1038 
1039 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1040 	int mode, const char *extension)
1041 {
1042 	u32 perm;
1043 	struct v9fs_session_info *v9ses;
1044 	struct p9_fid *fid;
1045 
1046 	v9ses = v9fs_inode2v9ses(dir);
1047 	if (!v9fs_extended(v9ses)) {
1048 		P9_DPRINTK(P9_DEBUG_ERROR, "not extended\n");
1049 		return -EPERM;
1050 	}
1051 
1052 	perm = unixmode2p9mode(v9ses, mode);
1053 	fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1054 								P9_OREAD);
1055 	if (IS_ERR(fid))
1056 		return PTR_ERR(fid);
1057 
1058 	p9_client_clunk(fid);
1059 	return 0;
1060 }
1061 
1062 /**
1063  * v9fs_vfs_symlink - helper function to create symlinks
1064  * @dir: directory inode containing symlink
1065  * @dentry: dentry for symlink
1066  * @symname: symlink data
1067  *
1068  * See Also: 9P2000.u RFC for more information
1069  *
1070  */
1071 
1072 static int
1073 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1074 {
1075 	P9_DPRINTK(P9_DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino,
1076 					dentry->d_name.name, symname);
1077 
1078 	return v9fs_vfs_mkspecial(dir, dentry, S_IFLNK, symname);
1079 }
1080 
1081 /**
1082  * v9fs_vfs_link - create a hardlink
1083  * @old_dentry: dentry for file to link to
1084  * @dir: inode destination for new link
1085  * @dentry: dentry for link
1086  *
1087  */
1088 
1089 static int
1090 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1091 	      struct dentry *dentry)
1092 {
1093 	int retval;
1094 	struct p9_fid *oldfid;
1095 	char *name;
1096 
1097 	P9_DPRINTK(P9_DEBUG_VFS,
1098 		" %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
1099 		old_dentry->d_name.name);
1100 
1101 	oldfid = v9fs_fid_clone(old_dentry);
1102 	if (IS_ERR(oldfid))
1103 		return PTR_ERR(oldfid);
1104 
1105 	name = __getname();
1106 	if (unlikely(!name)) {
1107 		retval = -ENOMEM;
1108 		goto clunk_fid;
1109 	}
1110 
1111 	sprintf(name, "%d\n", oldfid->fid);
1112 	retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1113 	__putname(name);
1114 
1115 clunk_fid:
1116 	p9_client_clunk(oldfid);
1117 	return retval;
1118 }
1119 
1120 /**
1121  * v9fs_vfs_mknod - create a special file
1122  * @dir: inode destination for new link
1123  * @dentry: dentry for file
1124  * @mode: mode for creation
1125  * @rdev: device associated with special file
1126  *
1127  */
1128 
1129 static int
1130 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
1131 {
1132 	int retval;
1133 	char *name;
1134 
1135 	P9_DPRINTK(P9_DEBUG_VFS,
1136 		" %lu,%s mode: %x MAJOR: %u MINOR: %u\n", dir->i_ino,
1137 		dentry->d_name.name, mode, MAJOR(rdev), MINOR(rdev));
1138 
1139 	if (!new_valid_dev(rdev))
1140 		return -EINVAL;
1141 
1142 	name = __getname();
1143 	if (!name)
1144 		return -ENOMEM;
1145 	/* build extension */
1146 	if (S_ISBLK(mode))
1147 		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1148 	else if (S_ISCHR(mode))
1149 		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1150 	else if (S_ISFIFO(mode))
1151 		*name = 0;
1152 	else {
1153 		__putname(name);
1154 		return -EINVAL;
1155 	}
1156 
1157 	retval = v9fs_vfs_mkspecial(dir, dentry, mode, name);
1158 	__putname(name);
1159 
1160 	return retval;
1161 }
1162 
1163 static const struct inode_operations v9fs_dir_inode_operations_ext = {
1164 	.create = v9fs_vfs_create,
1165 	.lookup = v9fs_vfs_lookup,
1166 	.symlink = v9fs_vfs_symlink,
1167 	.link = v9fs_vfs_link,
1168 	.unlink = v9fs_vfs_unlink,
1169 	.mkdir = v9fs_vfs_mkdir,
1170 	.rmdir = v9fs_vfs_rmdir,
1171 	.mknod = v9fs_vfs_mknod,
1172 	.rename = v9fs_vfs_rename,
1173 	.readlink = v9fs_vfs_readlink,
1174 	.getattr = v9fs_vfs_getattr,
1175 	.setattr = v9fs_vfs_setattr,
1176 };
1177 
1178 static const struct inode_operations v9fs_dir_inode_operations = {
1179 	.create = v9fs_vfs_create,
1180 	.lookup = v9fs_vfs_lookup,
1181 	.unlink = v9fs_vfs_unlink,
1182 	.mkdir = v9fs_vfs_mkdir,
1183 	.rmdir = v9fs_vfs_rmdir,
1184 	.mknod = v9fs_vfs_mknod,
1185 	.rename = v9fs_vfs_rename,
1186 	.getattr = v9fs_vfs_getattr,
1187 	.setattr = v9fs_vfs_setattr,
1188 };
1189 
1190 static const struct inode_operations v9fs_file_inode_operations = {
1191 	.getattr = v9fs_vfs_getattr,
1192 	.setattr = v9fs_vfs_setattr,
1193 };
1194 
1195 static const struct inode_operations v9fs_symlink_inode_operations = {
1196 	.readlink = v9fs_vfs_readlink,
1197 	.follow_link = v9fs_vfs_follow_link,
1198 	.put_link = v9fs_vfs_put_link,
1199 	.getattr = v9fs_vfs_getattr,
1200 	.setattr = v9fs_vfs_setattr,
1201 };
1202