xref: /openbmc/linux/fs/9p/vfs_inode.c (revision 22246614)
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 int v9fs_uflags2omode(int uflags)
133 {
134 	int ret;
135 
136 	ret = 0;
137 	switch (uflags&3) {
138 	default:
139 	case O_RDONLY:
140 		ret = P9_OREAD;
141 		break;
142 
143 	case O_WRONLY:
144 		ret = P9_OWRITE;
145 		break;
146 
147 	case O_RDWR:
148 		ret = P9_ORDWR;
149 		break;
150 	}
151 
152 	if (uflags & O_EXCL)
153 		ret |= P9_OEXCL;
154 
155 	if (uflags & O_TRUNC)
156 		ret |= P9_OTRUNC;
157 
158 	if (uflags & O_APPEND)
159 		ret |= P9_OAPPEND;
160 
161 	return ret;
162 }
163 
164 /**
165  * v9fs_blank_wstat - helper function to setup a 9P stat structure
166  * @v9ses: 9P session info (for determining extended mode)
167  * @wstat: structure to initialize
168  *
169  */
170 
171 static void
172 v9fs_blank_wstat(struct p9_wstat *wstat)
173 {
174 	wstat->type = ~0;
175 	wstat->dev = ~0;
176 	wstat->qid.type = ~0;
177 	wstat->qid.version = ~0;
178 	*((long long *)&wstat->qid.path) = ~0;
179 	wstat->mode = ~0;
180 	wstat->atime = ~0;
181 	wstat->mtime = ~0;
182 	wstat->length = ~0;
183 	wstat->name = NULL;
184 	wstat->uid = NULL;
185 	wstat->gid = NULL;
186 	wstat->muid = NULL;
187 	wstat->n_uid = ~0;
188 	wstat->n_gid = ~0;
189 	wstat->n_muid = ~0;
190 	wstat->extension = NULL;
191 }
192 
193 /**
194  * v9fs_get_inode - helper function to setup an inode
195  * @sb: superblock
196  * @mode: mode to setup inode with
197  *
198  */
199 
200 struct inode *v9fs_get_inode(struct super_block *sb, int mode)
201 {
202 	struct inode *inode;
203 	struct v9fs_session_info *v9ses = sb->s_fs_info;
204 
205 	P9_DPRINTK(P9_DEBUG_VFS, "super block: %p mode: %o\n", sb, mode);
206 
207 	inode = new_inode(sb);
208 	if (inode) {
209 		inode->i_mode = mode;
210 		inode->i_uid = current->fsuid;
211 		inode->i_gid = current->fsgid;
212 		inode->i_blocks = 0;
213 		inode->i_rdev = 0;
214 		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
215 		inode->i_mapping->a_ops = &v9fs_addr_operations;
216 
217 		switch (mode & S_IFMT) {
218 		case S_IFIFO:
219 		case S_IFBLK:
220 		case S_IFCHR:
221 		case S_IFSOCK:
222 			if (!v9fs_extended(v9ses)) {
223 				P9_DPRINTK(P9_DEBUG_ERROR,
224 				      "special files without extended mode\n");
225 				return ERR_PTR(-EINVAL);
226 			}
227 			init_special_inode(inode, inode->i_mode,
228 					   inode->i_rdev);
229 			break;
230 		case S_IFREG:
231 			inode->i_op = &v9fs_file_inode_operations;
232 			inode->i_fop = &v9fs_file_operations;
233 			break;
234 		case S_IFLNK:
235 			if (!v9fs_extended(v9ses)) {
236 				P9_DPRINTK(P9_DEBUG_ERROR,
237 					"extended modes used w/o 9P2000.u\n");
238 				return ERR_PTR(-EINVAL);
239 			}
240 			inode->i_op = &v9fs_symlink_inode_operations;
241 			break;
242 		case S_IFDIR:
243 			inc_nlink(inode);
244 			if (v9fs_extended(v9ses))
245 				inode->i_op = &v9fs_dir_inode_operations_ext;
246 			else
247 				inode->i_op = &v9fs_dir_inode_operations;
248 			inode->i_fop = &v9fs_dir_operations;
249 			break;
250 		default:
251 			P9_DPRINTK(P9_DEBUG_ERROR,
252 				"BAD mode 0x%x S_IFMT 0x%x\n",
253 				mode, mode & S_IFMT);
254 			return ERR_PTR(-EINVAL);
255 		}
256 	} else {
257 		P9_EPRINTK(KERN_WARNING, "Problem allocating inode\n");
258 		return ERR_PTR(-ENOMEM);
259 	}
260 	return inode;
261 }
262 
263 /*
264 static struct v9fs_fid*
265 v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
266 {
267 	int err;
268 	int nfid;
269 	struct v9fs_fid *ret;
270 	struct v9fs_fcall *fcall;
271 
272 	nfid = v9fs_get_idpool(&v9ses->fidpool);
273 	if (nfid < 0) {
274 		eprintk(KERN_WARNING, "no free fids available\n");
275 		return ERR_PTR(-ENOSPC);
276 	}
277 
278 	err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
279 		&fcall);
280 
281 	if (err < 0) {
282 		if (fcall && fcall->id == RWALK)
283 			goto clunk_fid;
284 
285 		PRINT_FCALL_ERROR("walk error", fcall);
286 		v9fs_put_idpool(nfid, &v9ses->fidpool);
287 		goto error;
288 	}
289 
290 	kfree(fcall);
291 	fcall = NULL;
292 	ret = v9fs_fid_create(v9ses, nfid);
293 	if (!ret) {
294 		err = -ENOMEM;
295 		goto clunk_fid;
296 	}
297 
298 	err = v9fs_fid_insert(ret, dentry);
299 	if (err < 0) {
300 		v9fs_fid_destroy(ret);
301 		goto clunk_fid;
302 	}
303 
304 	return ret;
305 
306 clunk_fid:
307 	v9fs_t_clunk(v9ses, nfid);
308 
309 error:
310 	kfree(fcall);
311 	return ERR_PTR(err);
312 }
313 */
314 
315 static struct inode *
316 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
317 	struct super_block *sb)
318 {
319 	int err, umode;
320 	struct inode *ret;
321 	struct p9_stat *st;
322 
323 	ret = NULL;
324 	st = p9_client_stat(fid);
325 	if (IS_ERR(st)) {
326 		err = PTR_ERR(st);
327 		st = NULL;
328 		goto error;
329 	}
330 
331 	umode = p9mode2unixmode(v9ses, st->mode);
332 	ret = v9fs_get_inode(sb, umode);
333 	if (IS_ERR(ret)) {
334 		err = PTR_ERR(ret);
335 		ret = NULL;
336 		goto error;
337 	}
338 
339 	v9fs_stat2inode(st, ret, sb);
340 	ret->i_ino = v9fs_qid2ino(&st->qid);
341 	kfree(st);
342 	return ret;
343 
344 error:
345 	kfree(st);
346 	if (ret)
347 		iput(ret);
348 
349 	return ERR_PTR(err);
350 }
351 
352 /**
353  * v9fs_remove - helper function to remove files and directories
354  * @dir: directory inode that is being deleted
355  * @file:  dentry that is being deleted
356  * @rmdir: removing a directory
357  *
358  */
359 
360 static int v9fs_remove(struct inode *dir, struct dentry *file, int rmdir)
361 {
362 	struct inode *file_inode;
363 	struct v9fs_session_info *v9ses;
364 	struct p9_fid *v9fid;
365 
366 	P9_DPRINTK(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %d\n", dir, file,
367 		rmdir);
368 
369 	file_inode = file->d_inode;
370 	v9ses = v9fs_inode2v9ses(file_inode);
371 	v9fid = v9fs_fid_clone(file);
372 	if (IS_ERR(v9fid))
373 		return PTR_ERR(v9fid);
374 
375 	return p9_client_remove(v9fid);
376 }
377 
378 static int
379 v9fs_open_created(struct inode *inode, struct file *file)
380 {
381 	return 0;
382 }
383 
384 
385 /**
386  * v9fs_create - Create a file
387  * @dentry:  dentry that is being created
388  * @perm: create permissions
389  * @mode: open mode
390  *
391  */
392 static struct p9_fid *
393 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
394 		struct dentry *dentry, char *extension, u32 perm, u8 mode)
395 {
396 	int err;
397 	char *name;
398 	struct p9_fid *dfid, *ofid, *fid;
399 	struct inode *inode;
400 
401 	err = 0;
402 	ofid = NULL;
403 	fid = NULL;
404 	name = (char *) dentry->d_name.name;
405 	dfid = v9fs_fid_clone(dentry->d_parent);
406 	if (IS_ERR(dfid)) {
407 		err = PTR_ERR(dfid);
408 		dfid = NULL;
409 		goto error;
410 	}
411 
412 	/* clone a fid to use for creation */
413 	ofid = p9_client_walk(dfid, 0, NULL, 1);
414 	if (IS_ERR(ofid)) {
415 		err = PTR_ERR(ofid);
416 		ofid = NULL;
417 		goto error;
418 	}
419 
420 	err = p9_client_fcreate(ofid, name, perm, mode, extension);
421 	if (err < 0)
422 		goto error;
423 
424 	/* now walk from the parent so we can get unopened fid */
425 	fid = p9_client_walk(dfid, 1, &name, 0);
426 	if (IS_ERR(fid)) {
427 		err = PTR_ERR(fid);
428 		fid = NULL;
429 		goto error;
430 	} else
431 		dfid = NULL;
432 
433 	/* instantiate inode and assign the unopened fid to the dentry */
434 	inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
435 	if (IS_ERR(inode)) {
436 		err = PTR_ERR(inode);
437 		goto error;
438 	}
439 
440 	if (v9ses->cache)
441 		dentry->d_op = &v9fs_cached_dentry_operations;
442 	else
443 		dentry->d_op = &v9fs_dentry_operations;
444 
445 	d_instantiate(dentry, inode);
446 	v9fs_fid_add(dentry, fid);
447 	return ofid;
448 
449 error:
450 	if (dfid)
451 		p9_client_clunk(dfid);
452 
453 	if (ofid)
454 		p9_client_clunk(ofid);
455 
456 	if (fid)
457 		p9_client_clunk(fid);
458 
459 	return ERR_PTR(err);
460 }
461 
462 /**
463  * v9fs_vfs_create - VFS hook to create files
464  * @inode: directory inode that is being created
465  * @dentry:  dentry that is being deleted
466  * @mode: create permissions
467  * @nd: path information
468  *
469  */
470 
471 static int
472 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
473 		struct nameidata *nd)
474 {
475 	int err;
476 	u32 perm;
477 	int flags;
478 	struct v9fs_session_info *v9ses;
479 	struct p9_fid *fid;
480 	struct file *filp;
481 
482 	err = 0;
483 	fid = NULL;
484 	v9ses = v9fs_inode2v9ses(dir);
485 	perm = unixmode2p9mode(v9ses, mode);
486 	if (nd && nd->flags & LOOKUP_OPEN)
487 		flags = nd->intent.open.flags - 1;
488 	else
489 		flags = O_RDWR;
490 
491 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
492 						v9fs_uflags2omode(flags));
493 	if (IS_ERR(fid)) {
494 		err = PTR_ERR(fid);
495 		fid = NULL;
496 		goto error;
497 	}
498 
499 	/* if we are opening a file, assign the open fid to the file */
500 	if (nd && nd->flags & LOOKUP_OPEN) {
501 		filp = lookup_instantiate_filp(nd, dentry, v9fs_open_created);
502 		if (IS_ERR(filp)) {
503 			err = PTR_ERR(filp);
504 			goto error;
505 		}
506 
507 		filp->private_data = fid;
508 	} else
509 		p9_client_clunk(fid);
510 
511 	return 0;
512 
513 error:
514 	if (fid)
515 		p9_client_clunk(fid);
516 
517 	return err;
518 }
519 
520 /**
521  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
522  * @inode:  inode that is being unlinked
523  * @dentry: dentry that is being unlinked
524  * @mode: mode for new directory
525  *
526  */
527 
528 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
529 {
530 	int err;
531 	u32 perm;
532 	struct v9fs_session_info *v9ses;
533 	struct p9_fid *fid;
534 
535 	P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
536 	err = 0;
537 	v9ses = v9fs_inode2v9ses(dir);
538 	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
539 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
540 	if (IS_ERR(fid)) {
541 		err = PTR_ERR(fid);
542 		fid = NULL;
543 	}
544 
545 	if (fid)
546 		p9_client_clunk(fid);
547 
548 	return err;
549 }
550 
551 /**
552  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
553  * @dir:  inode that is being walked from
554  * @dentry: dentry that is being walked to?
555  * @nameidata: path data
556  *
557  */
558 
559 static struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
560 				      struct nameidata *nameidata)
561 {
562 	struct super_block *sb;
563 	struct v9fs_session_info *v9ses;
564 	struct p9_fid *dfid, *fid;
565 	struct inode *inode;
566 	char *name;
567 	int result = 0;
568 
569 	P9_DPRINTK(P9_DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
570 		dir, dentry->d_name.name, dentry, nameidata);
571 
572 	sb = dir->i_sb;
573 	v9ses = v9fs_inode2v9ses(dir);
574 	dfid = v9fs_fid_lookup(dentry->d_parent);
575 	if (IS_ERR(dfid))
576 		return ERR_CAST(dfid);
577 
578 	name = (char *) dentry->d_name.name;
579 	fid = p9_client_walk(dfid, 1, &name, 1);
580 	if (IS_ERR(fid)) {
581 		result = PTR_ERR(fid);
582 		if (result == -ENOENT) {
583 			d_add(dentry, NULL);
584 			return NULL;
585 		}
586 
587 		return ERR_PTR(result);
588 	}
589 
590 	inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
591 	if (IS_ERR(inode)) {
592 		result = PTR_ERR(inode);
593 		inode = NULL;
594 		goto error;
595 	}
596 
597 	result = v9fs_fid_add(dentry, fid);
598 	if (result < 0)
599 		goto error;
600 
601 	if ((fid->qid.version) && (v9ses->cache))
602 		dentry->d_op = &v9fs_cached_dentry_operations;
603 	else
604 		dentry->d_op = &v9fs_dentry_operations;
605 
606 	d_add(dentry, inode);
607 	return NULL;
608 
609 error:
610 	if (fid)
611 		p9_client_clunk(fid);
612 
613 	return ERR_PTR(result);
614 }
615 
616 /**
617  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
618  * @i:  inode that is being unlinked
619  * @d: dentry that is being unlinked
620  *
621  */
622 
623 static int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
624 {
625 	return v9fs_remove(i, d, 0);
626 }
627 
628 /**
629  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
630  * @i:  inode that is being unlinked
631  * @d: dentry that is being unlinked
632  *
633  */
634 
635 static int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
636 {
637 	return v9fs_remove(i, d, 1);
638 }
639 
640 /**
641  * v9fs_vfs_rename - VFS hook to rename an inode
642  * @old_dir:  old dir inode
643  * @old_dentry: old dentry
644  * @new_dir: new dir inode
645  * @new_dentry: new dentry
646  *
647  */
648 
649 static int
650 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
651 		struct inode *new_dir, struct dentry *new_dentry)
652 {
653 	struct inode *old_inode;
654 	struct v9fs_session_info *v9ses;
655 	struct p9_fid *oldfid;
656 	struct p9_fid *olddirfid;
657 	struct p9_fid *newdirfid;
658 	struct p9_wstat wstat;
659 	int retval;
660 
661 	P9_DPRINTK(P9_DEBUG_VFS, "\n");
662 	retval = 0;
663 	old_inode = old_dentry->d_inode;
664 	v9ses = v9fs_inode2v9ses(old_inode);
665 	oldfid = v9fs_fid_lookup(old_dentry);
666 	if (IS_ERR(oldfid))
667 		return PTR_ERR(oldfid);
668 
669 	olddirfid = v9fs_fid_clone(old_dentry->d_parent);
670 	if (IS_ERR(olddirfid)) {
671 		retval = PTR_ERR(olddirfid);
672 		goto done;
673 	}
674 
675 	newdirfid = v9fs_fid_clone(new_dentry->d_parent);
676 	if (IS_ERR(newdirfid)) {
677 		retval = PTR_ERR(newdirfid);
678 		goto clunk_olddir;
679 	}
680 
681 	/* 9P can only handle file rename in the same directory */
682 	if (memcmp(&olddirfid->qid, &newdirfid->qid, sizeof(newdirfid->qid))) {
683 		P9_DPRINTK(P9_DEBUG_ERROR,
684 				"old dir and new dir are different\n");
685 		retval = -EXDEV;
686 		goto clunk_newdir;
687 	}
688 
689 	v9fs_blank_wstat(&wstat);
690 	wstat.muid = v9ses->uname;
691 	wstat.name = (char *) new_dentry->d_name.name;
692 	retval = p9_client_wstat(oldfid, &wstat);
693 
694 clunk_newdir:
695 	p9_client_clunk(newdirfid);
696 
697 clunk_olddir:
698 	p9_client_clunk(olddirfid);
699 
700 done:
701 	return retval;
702 }
703 
704 /**
705  * v9fs_vfs_getattr - retrieve file metadata
706  * @mnt - mount information
707  * @dentry - file to get attributes on
708  * @stat - metadata structure to populate
709  *
710  */
711 
712 static int
713 v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
714 		 struct kstat *stat)
715 {
716 	int err;
717 	struct v9fs_session_info *v9ses;
718 	struct p9_fid *fid;
719 	struct p9_stat *st;
720 
721 	P9_DPRINTK(P9_DEBUG_VFS, "dentry: %p\n", dentry);
722 	err = -EPERM;
723 	v9ses = v9fs_inode2v9ses(dentry->d_inode);
724 	if (v9ses->cache == CACHE_LOOSE)
725 		return simple_getattr(mnt, dentry, stat);
726 
727 	fid = v9fs_fid_lookup(dentry);
728 	if (IS_ERR(fid))
729 		return PTR_ERR(fid);
730 
731 	st = p9_client_stat(fid);
732 	if (IS_ERR(st))
733 		return PTR_ERR(st);
734 
735 	v9fs_stat2inode(st, dentry->d_inode, dentry->d_inode->i_sb);
736 		generic_fillattr(dentry->d_inode, stat);
737 
738 	kfree(st);
739 	return 0;
740 }
741 
742 /**
743  * v9fs_vfs_setattr - set file metadata
744  * @dentry: file whose metadata to set
745  * @iattr: metadata assignment structure
746  *
747  */
748 
749 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
750 {
751 	int retval;
752 	struct v9fs_session_info *v9ses;
753 	struct p9_fid *fid;
754 	struct p9_wstat wstat;
755 
756 	P9_DPRINTK(P9_DEBUG_VFS, "\n");
757 	retval = -EPERM;
758 	v9ses = v9fs_inode2v9ses(dentry->d_inode);
759 	fid = v9fs_fid_lookup(dentry);
760 	if(IS_ERR(fid))
761 		return PTR_ERR(fid);
762 
763 	v9fs_blank_wstat(&wstat);
764 	if (iattr->ia_valid & ATTR_MODE)
765 		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
766 
767 	if (iattr->ia_valid & ATTR_MTIME)
768 		wstat.mtime = iattr->ia_mtime.tv_sec;
769 
770 	if (iattr->ia_valid & ATTR_ATIME)
771 		wstat.atime = iattr->ia_atime.tv_sec;
772 
773 	if (iattr->ia_valid & ATTR_SIZE)
774 		wstat.length = iattr->ia_size;
775 
776 	if (v9fs_extended(v9ses)) {
777 		if (iattr->ia_valid & ATTR_UID)
778 			wstat.n_uid = iattr->ia_uid;
779 
780 		if (iattr->ia_valid & ATTR_GID)
781 			wstat.n_gid = iattr->ia_gid;
782 	}
783 
784 	retval = p9_client_wstat(fid, &wstat);
785 	if (retval >= 0)
786 		retval = inode_setattr(dentry->d_inode, iattr);
787 
788 	return retval;
789 }
790 
791 /**
792  * v9fs_stat2inode - populate an inode structure with mistat info
793  * @stat: Plan 9 metadata (mistat) structure
794  * @inode: inode to populate
795  * @sb: superblock of filesystem
796  *
797  */
798 
799 void
800 v9fs_stat2inode(struct p9_stat *stat, struct inode *inode,
801 	struct super_block *sb)
802 {
803 	int n;
804 	char ext[32];
805 	struct v9fs_session_info *v9ses = sb->s_fs_info;
806 
807 	inode->i_nlink = 1;
808 
809 	inode->i_atime.tv_sec = stat->atime;
810 	inode->i_mtime.tv_sec = stat->mtime;
811 	inode->i_ctime.tv_sec = stat->mtime;
812 
813 	inode->i_uid = v9ses->dfltuid;
814 	inode->i_gid = v9ses->dfltgid;
815 
816 	if (v9fs_extended(v9ses)) {
817 		inode->i_uid = stat->n_uid;
818 		inode->i_gid = stat->n_gid;
819 	}
820 
821 	inode->i_mode = p9mode2unixmode(v9ses, stat->mode);
822 	if ((S_ISBLK(inode->i_mode)) || (S_ISCHR(inode->i_mode))) {
823 		char type = 0;
824 		int major = -1;
825 		int minor = -1;
826 
827 		n = stat->extension.len;
828 		if (n > sizeof(ext)-1)
829 			n = sizeof(ext)-1;
830 		memmove(ext, stat->extension.str, n);
831 		ext[n] = 0;
832 		sscanf(ext, "%c %u %u", &type, &major, &minor);
833 		switch (type) {
834 		case 'c':
835 			inode->i_mode &= ~S_IFBLK;
836 			inode->i_mode |= S_IFCHR;
837 			break;
838 		case 'b':
839 			break;
840 		default:
841 			P9_DPRINTK(P9_DEBUG_ERROR,
842 				"Unknown special type %c (%.*s)\n", type,
843 				stat->extension.len, stat->extension.str);
844 		};
845 		inode->i_rdev = MKDEV(major, minor);
846 	} else
847 		inode->i_rdev = 0;
848 
849 	inode->i_size = stat->length;
850 
851 	/* not real number of blocks, but 512 byte ones ... */
852 	inode->i_blocks = (inode->i_size + 512 - 1) >> 9;
853 }
854 
855 /**
856  * v9fs_qid2ino - convert qid into inode number
857  * @qid: qid to hash
858  *
859  * BUG: potential for inode number collisions?
860  */
861 
862 ino_t v9fs_qid2ino(struct p9_qid *qid)
863 {
864 	u64 path = qid->path + 2;
865 	ino_t i = 0;
866 
867 	if (sizeof(ino_t) == sizeof(path))
868 		memcpy(&i, &path, sizeof(ino_t));
869 	else
870 		i = (ino_t) (path ^ (path >> 32));
871 
872 	return i;
873 }
874 
875 /**
876  * v9fs_readlink - read a symlink's location (internal version)
877  * @dentry: dentry for symlink
878  * @buffer: buffer to load symlink location into
879  * @buflen: length of buffer
880  *
881  */
882 
883 static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
884 {
885 	int retval;
886 
887 	struct v9fs_session_info *v9ses;
888 	struct p9_fid *fid;
889 	struct p9_stat *st;
890 
891 	P9_DPRINTK(P9_DEBUG_VFS, " %s\n", dentry->d_name.name);
892 	retval = -EPERM;
893 	v9ses = v9fs_inode2v9ses(dentry->d_inode);
894 	fid = v9fs_fid_lookup(dentry);
895 	if (IS_ERR(fid))
896 		return PTR_ERR(fid);
897 
898 	if (!v9fs_extended(v9ses))
899 		return -EBADF;
900 
901 	st = p9_client_stat(fid);
902 	if (IS_ERR(st))
903 		return PTR_ERR(st);
904 
905 	if (!(st->mode & P9_DMSYMLINK)) {
906 		retval = -EINVAL;
907 		goto done;
908 	}
909 
910 	/* copy extension buffer into buffer */
911 	if (st->extension.len < buflen)
912 		buflen = st->extension.len + 1;
913 
914 	memmove(buffer, st->extension.str, buflen - 1);
915 	buffer[buflen-1] = 0;
916 
917 	P9_DPRINTK(P9_DEBUG_VFS,
918 		"%s -> %.*s (%s)\n", dentry->d_name.name, st->extension.len,
919 		st->extension.str, buffer);
920 
921 	retval = buflen;
922 
923 done:
924 	kfree(st);
925 	return retval;
926 }
927 
928 /**
929  * v9fs_vfs_readlink - read a symlink's location
930  * @dentry: dentry for symlink
931  * @buf: buffer to load symlink location into
932  * @buflen: length of buffer
933  *
934  */
935 
936 static int v9fs_vfs_readlink(struct dentry *dentry, char __user * buffer,
937 			     int buflen)
938 {
939 	int retval;
940 	int ret;
941 	char *link = __getname();
942 
943 	if (unlikely(!link))
944 		return -ENOMEM;
945 
946 	if (buflen > PATH_MAX)
947 		buflen = PATH_MAX;
948 
949 	P9_DPRINTK(P9_DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);
950 
951 	retval = v9fs_readlink(dentry, link, buflen);
952 
953 	if (retval > 0) {
954 		if ((ret = copy_to_user(buffer, link, retval)) != 0) {
955 			P9_DPRINTK(P9_DEBUG_ERROR,
956 					"problem copying to user: %d\n", ret);
957 			retval = ret;
958 		}
959 	}
960 
961 	__putname(link);
962 	return retval;
963 }
964 
965 /**
966  * v9fs_vfs_follow_link - follow a symlink path
967  * @dentry: dentry for symlink
968  * @nd: nameidata
969  *
970  */
971 
972 static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
973 {
974 	int len = 0;
975 	char *link = __getname();
976 
977 	P9_DPRINTK(P9_DEBUG_VFS, "%s n", dentry->d_name.name);
978 
979 	if (!link)
980 		link = ERR_PTR(-ENOMEM);
981 	else {
982 		len = v9fs_readlink(dentry, link, PATH_MAX);
983 
984 		if (len < 0) {
985 			__putname(link);
986 			link = ERR_PTR(len);
987 		} else
988 			link[len] = 0;
989 	}
990 	nd_set_link(nd, link);
991 
992 	return NULL;
993 }
994 
995 /**
996  * v9fs_vfs_put_link - release a symlink path
997  * @dentry: dentry for symlink
998  * @nd: nameidata
999  *
1000  */
1001 
1002 static void v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
1003 {
1004 	char *s = nd_get_link(nd);
1005 
1006 	P9_DPRINTK(P9_DEBUG_VFS, " %s %s\n", dentry->d_name.name, s);
1007 	if (!IS_ERR(s))
1008 		__putname(s);
1009 }
1010 
1011 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1012 	int mode, const char *extension)
1013 {
1014 	u32 perm;
1015 	struct v9fs_session_info *v9ses;
1016 	struct p9_fid *fid;
1017 
1018 	v9ses = v9fs_inode2v9ses(dir);
1019 	if (!v9fs_extended(v9ses)) {
1020 		P9_DPRINTK(P9_DEBUG_ERROR, "not extended\n");
1021 		return -EPERM;
1022 	}
1023 
1024 	perm = unixmode2p9mode(v9ses, mode);
1025 	fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1026 								P9_OREAD);
1027 	if (IS_ERR(fid))
1028 		return PTR_ERR(fid);
1029 
1030 	p9_client_clunk(fid);
1031 	return 0;
1032 }
1033 
1034 /**
1035  * v9fs_vfs_symlink - helper function to create symlinks
1036  * @dir: directory inode containing symlink
1037  * @dentry: dentry for symlink
1038  * @symname: symlink data
1039  *
1040  * See 9P2000.u RFC for more information
1041  *
1042  */
1043 
1044 static int
1045 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1046 {
1047 	P9_DPRINTK(P9_DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino,
1048 					dentry->d_name.name, symname);
1049 
1050 	return v9fs_vfs_mkspecial(dir, dentry, S_IFLNK, symname);
1051 }
1052 
1053 /**
1054  * v9fs_vfs_link - create a hardlink
1055  * @old_dentry: dentry for file to link to
1056  * @dir: inode destination for new link
1057  * @dentry: dentry for link
1058  *
1059  */
1060 
1061 /* XXX - lots of code dup'd from symlink and creates,
1062  * figure out a better reuse strategy
1063  */
1064 
1065 static int
1066 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1067 	      struct dentry *dentry)
1068 {
1069 	int retval;
1070 	struct p9_fid *oldfid;
1071 	char *name;
1072 
1073 	P9_DPRINTK(P9_DEBUG_VFS,
1074 		" %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
1075 		old_dentry->d_name.name);
1076 
1077 	oldfid = v9fs_fid_clone(old_dentry);
1078 	if (IS_ERR(oldfid))
1079 		return PTR_ERR(oldfid);
1080 
1081 	name = __getname();
1082 	if (unlikely(!name)) {
1083 		retval = -ENOMEM;
1084 		goto clunk_fid;
1085 	}
1086 
1087 	sprintf(name, "%d\n", oldfid->fid);
1088 	retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1089 	__putname(name);
1090 
1091 clunk_fid:
1092 	p9_client_clunk(oldfid);
1093 	return retval;
1094 }
1095 
1096 /**
1097  * v9fs_vfs_mknod - create a special file
1098  * @dir: inode destination for new link
1099  * @dentry: dentry for file
1100  * @mode: mode for creation
1101  * @dev_t: device associated with special file
1102  *
1103  */
1104 
1105 static int
1106 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
1107 {
1108 	int retval;
1109 	char *name;
1110 
1111 	P9_DPRINTK(P9_DEBUG_VFS,
1112 		" %lu,%s mode: %x MAJOR: %u MINOR: %u\n", dir->i_ino,
1113 		dentry->d_name.name, mode, MAJOR(rdev), MINOR(rdev));
1114 
1115 	if (!new_valid_dev(rdev))
1116 		return -EINVAL;
1117 
1118 	name = __getname();
1119 	if (!name)
1120 		return -ENOMEM;
1121 	/* build extension */
1122 	if (S_ISBLK(mode))
1123 		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1124 	else if (S_ISCHR(mode))
1125 		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1126 	else if (S_ISFIFO(mode))
1127 		*name = 0;
1128 	else {
1129 		__putname(name);
1130 		return -EINVAL;
1131 	}
1132 
1133 	retval = v9fs_vfs_mkspecial(dir, dentry, mode, name);
1134 	__putname(name);
1135 
1136 	return retval;
1137 }
1138 
1139 static const struct inode_operations v9fs_dir_inode_operations_ext = {
1140 	.create = v9fs_vfs_create,
1141 	.lookup = v9fs_vfs_lookup,
1142 	.symlink = v9fs_vfs_symlink,
1143 	.link = v9fs_vfs_link,
1144 	.unlink = v9fs_vfs_unlink,
1145 	.mkdir = v9fs_vfs_mkdir,
1146 	.rmdir = v9fs_vfs_rmdir,
1147 	.mknod = v9fs_vfs_mknod,
1148 	.rename = v9fs_vfs_rename,
1149 	.readlink = v9fs_vfs_readlink,
1150 	.getattr = v9fs_vfs_getattr,
1151 	.setattr = v9fs_vfs_setattr,
1152 };
1153 
1154 static const struct inode_operations v9fs_dir_inode_operations = {
1155 	.create = v9fs_vfs_create,
1156 	.lookup = v9fs_vfs_lookup,
1157 	.unlink = v9fs_vfs_unlink,
1158 	.mkdir = v9fs_vfs_mkdir,
1159 	.rmdir = v9fs_vfs_rmdir,
1160 	.mknod = v9fs_vfs_mknod,
1161 	.rename = v9fs_vfs_rename,
1162 	.getattr = v9fs_vfs_getattr,
1163 	.setattr = v9fs_vfs_setattr,
1164 };
1165 
1166 static const struct inode_operations v9fs_file_inode_operations = {
1167 	.getattr = v9fs_vfs_getattr,
1168 	.setattr = v9fs_vfs_setattr,
1169 };
1170 
1171 static const struct inode_operations v9fs_symlink_inode_operations = {
1172 	.readlink = v9fs_vfs_readlink,
1173 	.follow_link = v9fs_vfs_follow_link,
1174 	.put_link = v9fs_vfs_put_link,
1175 	.getattr = v9fs_vfs_getattr,
1176 	.setattr = v9fs_vfs_setattr,
1177 };
1178