xref: /openbmc/linux/fs/9p/vfs_inode.c (revision 384740dc)
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  * @extended: if .u extensions are active
136  */
137 
138 int v9fs_uflags2omode(int uflags, int extended)
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_TRUNC)
159 		ret |= P9_OTRUNC;
160 
161 	if (extended) {
162 		if (uflags & O_EXCL)
163 			ret |= P9_OEXCL;
164 
165 		if (uflags & O_APPEND)
166 			ret |= P9_OAPPEND;
167 	}
168 
169 	return ret;
170 }
171 
172 /**
173  * v9fs_blank_wstat - helper function to setup a 9P stat structure
174  * @v9ses: 9P session info (for determining extended mode)
175  * @wstat: structure to initialize
176  *
177  */
178 
179 static void
180 v9fs_blank_wstat(struct p9_wstat *wstat)
181 {
182 	wstat->type = ~0;
183 	wstat->dev = ~0;
184 	wstat->qid.type = ~0;
185 	wstat->qid.version = ~0;
186 	*((long long *)&wstat->qid.path) = ~0;
187 	wstat->mode = ~0;
188 	wstat->atime = ~0;
189 	wstat->mtime = ~0;
190 	wstat->length = ~0;
191 	wstat->name = NULL;
192 	wstat->uid = NULL;
193 	wstat->gid = NULL;
194 	wstat->muid = NULL;
195 	wstat->n_uid = ~0;
196 	wstat->n_gid = ~0;
197 	wstat->n_muid = ~0;
198 	wstat->extension = NULL;
199 }
200 
201 /**
202  * v9fs_get_inode - helper function to setup an inode
203  * @sb: superblock
204  * @mode: mode to setup inode with
205  *
206  */
207 
208 struct inode *v9fs_get_inode(struct super_block *sb, int mode)
209 {
210 	struct inode *inode;
211 	struct v9fs_session_info *v9ses = sb->s_fs_info;
212 
213 	P9_DPRINTK(P9_DEBUG_VFS, "super block: %p mode: %o\n", sb, mode);
214 
215 	inode = new_inode(sb);
216 	if (inode) {
217 		inode->i_mode = mode;
218 		inode->i_uid = current->fsuid;
219 		inode->i_gid = current->fsgid;
220 		inode->i_blocks = 0;
221 		inode->i_rdev = 0;
222 		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
223 		inode->i_mapping->a_ops = &v9fs_addr_operations;
224 
225 		switch (mode & S_IFMT) {
226 		case S_IFIFO:
227 		case S_IFBLK:
228 		case S_IFCHR:
229 		case S_IFSOCK:
230 			if (!v9fs_extended(v9ses)) {
231 				P9_DPRINTK(P9_DEBUG_ERROR,
232 				      "special files without extended mode\n");
233 				return ERR_PTR(-EINVAL);
234 			}
235 			init_special_inode(inode, inode->i_mode,
236 					   inode->i_rdev);
237 			break;
238 		case S_IFREG:
239 			inode->i_op = &v9fs_file_inode_operations;
240 			inode->i_fop = &v9fs_file_operations;
241 			break;
242 		case S_IFLNK:
243 			if (!v9fs_extended(v9ses)) {
244 				P9_DPRINTK(P9_DEBUG_ERROR,
245 					"extended modes used w/o 9P2000.u\n");
246 				return ERR_PTR(-EINVAL);
247 			}
248 			inode->i_op = &v9fs_symlink_inode_operations;
249 			break;
250 		case S_IFDIR:
251 			inc_nlink(inode);
252 			if (v9fs_extended(v9ses))
253 				inode->i_op = &v9fs_dir_inode_operations_ext;
254 			else
255 				inode->i_op = &v9fs_dir_inode_operations;
256 			inode->i_fop = &v9fs_dir_operations;
257 			break;
258 		default:
259 			P9_DPRINTK(P9_DEBUG_ERROR,
260 				"BAD mode 0x%x S_IFMT 0x%x\n",
261 				mode, mode & S_IFMT);
262 			return ERR_PTR(-EINVAL);
263 		}
264 	} else {
265 		P9_EPRINTK(KERN_WARNING, "Problem allocating inode\n");
266 		return ERR_PTR(-ENOMEM);
267 	}
268 	return inode;
269 }
270 
271 /*
272 static struct v9fs_fid*
273 v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
274 {
275 	int err;
276 	int nfid;
277 	struct v9fs_fid *ret;
278 	struct v9fs_fcall *fcall;
279 
280 	nfid = v9fs_get_idpool(&v9ses->fidpool);
281 	if (nfid < 0) {
282 		eprintk(KERN_WARNING, "no free fids available\n");
283 		return ERR_PTR(-ENOSPC);
284 	}
285 
286 	err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
287 		&fcall);
288 
289 	if (err < 0) {
290 		if (fcall && fcall->id == RWALK)
291 			goto clunk_fid;
292 
293 		PRINT_FCALL_ERROR("walk error", fcall);
294 		v9fs_put_idpool(nfid, &v9ses->fidpool);
295 		goto error;
296 	}
297 
298 	kfree(fcall);
299 	fcall = NULL;
300 	ret = v9fs_fid_create(v9ses, nfid);
301 	if (!ret) {
302 		err = -ENOMEM;
303 		goto clunk_fid;
304 	}
305 
306 	err = v9fs_fid_insert(ret, dentry);
307 	if (err < 0) {
308 		v9fs_fid_destroy(ret);
309 		goto clunk_fid;
310 	}
311 
312 	return ret;
313 
314 clunk_fid:
315 	v9fs_t_clunk(v9ses, nfid);
316 
317 error:
318 	kfree(fcall);
319 	return ERR_PTR(err);
320 }
321 */
322 
323 /**
324  * v9fs_inode_from_fid - populate an inode by issuing a attribute request
325  * @v9ses: session information
326  * @fid: fid to issue attribute request for
327  * @sb: superblock on which to create inode
328  *
329  */
330 
331 static struct inode *
332 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
333 	struct super_block *sb)
334 {
335 	int err, umode;
336 	struct inode *ret;
337 	struct p9_stat *st;
338 
339 	ret = NULL;
340 	st = p9_client_stat(fid);
341 	if (IS_ERR(st)) {
342 		err = PTR_ERR(st);
343 		st = NULL;
344 		goto error;
345 	}
346 
347 	umode = p9mode2unixmode(v9ses, st->mode);
348 	ret = v9fs_get_inode(sb, umode);
349 	if (IS_ERR(ret)) {
350 		err = PTR_ERR(ret);
351 		ret = NULL;
352 		goto error;
353 	}
354 
355 	v9fs_stat2inode(st, ret, sb);
356 	ret->i_ino = v9fs_qid2ino(&st->qid);
357 	kfree(st);
358 	return ret;
359 
360 error:
361 	kfree(st);
362 	if (ret)
363 		iput(ret);
364 
365 	return ERR_PTR(err);
366 }
367 
368 /**
369  * v9fs_remove - helper function to remove files and directories
370  * @dir: directory inode that is being deleted
371  * @file:  dentry that is being deleted
372  * @rmdir: removing a directory
373  *
374  */
375 
376 static int v9fs_remove(struct inode *dir, struct dentry *file, int rmdir)
377 {
378 	struct inode *file_inode;
379 	struct v9fs_session_info *v9ses;
380 	struct p9_fid *v9fid;
381 
382 	P9_DPRINTK(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %d\n", dir, file,
383 		rmdir);
384 
385 	file_inode = file->d_inode;
386 	v9ses = v9fs_inode2v9ses(file_inode);
387 	v9fid = v9fs_fid_clone(file);
388 	if (IS_ERR(v9fid))
389 		return PTR_ERR(v9fid);
390 
391 	return p9_client_remove(v9fid);
392 }
393 
394 static int
395 v9fs_open_created(struct inode *inode, struct file *file)
396 {
397 	return 0;
398 }
399 
400 
401 /**
402  * v9fs_create - Create a file
403  * @v9ses: session information
404  * @dir: directory that dentry is being created in
405  * @dentry:  dentry that is being created
406  * @perm: create permissions
407  * @mode: open mode
408  * @extension: 9p2000.u extension string to support devices, etc.
409  *
410  */
411 static struct p9_fid *
412 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
413 		struct dentry *dentry, char *extension, u32 perm, u8 mode)
414 {
415 	int err;
416 	char *name;
417 	struct p9_fid *dfid, *ofid, *fid;
418 	struct inode *inode;
419 
420 	err = 0;
421 	ofid = NULL;
422 	fid = NULL;
423 	name = (char *) dentry->d_name.name;
424 	dfid = v9fs_fid_clone(dentry->d_parent);
425 	if (IS_ERR(dfid)) {
426 		err = PTR_ERR(dfid);
427 		dfid = NULL;
428 		goto error;
429 	}
430 
431 	/* clone a fid to use for creation */
432 	ofid = p9_client_walk(dfid, 0, NULL, 1);
433 	if (IS_ERR(ofid)) {
434 		err = PTR_ERR(ofid);
435 		ofid = NULL;
436 		goto error;
437 	}
438 
439 	err = p9_client_fcreate(ofid, name, perm, mode, extension);
440 	if (err < 0)
441 		goto error;
442 
443 	/* now walk from the parent so we can get unopened fid */
444 	fid = p9_client_walk(dfid, 1, &name, 0);
445 	if (IS_ERR(fid)) {
446 		err = PTR_ERR(fid);
447 		fid = NULL;
448 		goto error;
449 	} else
450 		dfid = NULL;
451 
452 	/* instantiate inode and assign the unopened fid to the dentry */
453 	inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
454 	if (IS_ERR(inode)) {
455 		err = PTR_ERR(inode);
456 		goto error;
457 	}
458 
459 	if (v9ses->cache)
460 		dentry->d_op = &v9fs_cached_dentry_operations;
461 	else
462 		dentry->d_op = &v9fs_dentry_operations;
463 
464 	d_instantiate(dentry, inode);
465 	v9fs_fid_add(dentry, fid);
466 	return ofid;
467 
468 error:
469 	if (dfid)
470 		p9_client_clunk(dfid);
471 
472 	if (ofid)
473 		p9_client_clunk(ofid);
474 
475 	if (fid)
476 		p9_client_clunk(fid);
477 
478 	return ERR_PTR(err);
479 }
480 
481 /**
482  * v9fs_vfs_create - VFS hook to create files
483  * @dir: directory inode that is being created
484  * @dentry:  dentry that is being deleted
485  * @mode: create permissions
486  * @nd: path information
487  *
488  */
489 
490 static int
491 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
492 		struct nameidata *nd)
493 {
494 	int err;
495 	u32 perm;
496 	int flags;
497 	struct v9fs_session_info *v9ses;
498 	struct p9_fid *fid;
499 	struct file *filp;
500 
501 	err = 0;
502 	fid = NULL;
503 	v9ses = v9fs_inode2v9ses(dir);
504 	perm = unixmode2p9mode(v9ses, mode);
505 	if (nd && nd->flags & LOOKUP_OPEN)
506 		flags = nd->intent.open.flags - 1;
507 	else
508 		flags = O_RDWR;
509 
510 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
511 				v9fs_uflags2omode(flags, v9fs_extended(v9ses)));
512 	if (IS_ERR(fid)) {
513 		err = PTR_ERR(fid);
514 		fid = NULL;
515 		goto error;
516 	}
517 
518 	/* if we are opening a file, assign the open fid to the file */
519 	if (nd && nd->flags & LOOKUP_OPEN) {
520 		filp = lookup_instantiate_filp(nd, dentry, v9fs_open_created);
521 		if (IS_ERR(filp)) {
522 			err = PTR_ERR(filp);
523 			goto error;
524 		}
525 
526 		filp->private_data = fid;
527 	} else
528 		p9_client_clunk(fid);
529 
530 	return 0;
531 
532 error:
533 	if (fid)
534 		p9_client_clunk(fid);
535 
536 	return err;
537 }
538 
539 /**
540  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
541  * @dir:  inode that is being unlinked
542  * @dentry: dentry that is being unlinked
543  * @mode: mode for new directory
544  *
545  */
546 
547 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
548 {
549 	int err;
550 	u32 perm;
551 	struct v9fs_session_info *v9ses;
552 	struct p9_fid *fid;
553 
554 	P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
555 	err = 0;
556 	v9ses = v9fs_inode2v9ses(dir);
557 	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
558 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
559 	if (IS_ERR(fid)) {
560 		err = PTR_ERR(fid);
561 		fid = NULL;
562 	}
563 
564 	if (fid)
565 		p9_client_clunk(fid);
566 
567 	return err;
568 }
569 
570 /**
571  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
572  * @dir:  inode that is being walked from
573  * @dentry: dentry that is being walked to?
574  * @nameidata: path data
575  *
576  */
577 
578 static struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
579 				      struct nameidata *nameidata)
580 {
581 	struct super_block *sb;
582 	struct v9fs_session_info *v9ses;
583 	struct p9_fid *dfid, *fid;
584 	struct inode *inode;
585 	char *name;
586 	int result = 0;
587 
588 	P9_DPRINTK(P9_DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
589 		dir, dentry->d_name.name, dentry, nameidata);
590 
591 	sb = dir->i_sb;
592 	v9ses = v9fs_inode2v9ses(dir);
593 	dfid = v9fs_fid_lookup(dentry->d_parent);
594 	if (IS_ERR(dfid))
595 		return ERR_CAST(dfid);
596 
597 	name = (char *) dentry->d_name.name;
598 	fid = p9_client_walk(dfid, 1, &name, 1);
599 	if (IS_ERR(fid)) {
600 		result = PTR_ERR(fid);
601 		if (result == -ENOENT) {
602 			d_add(dentry, NULL);
603 			return NULL;
604 		}
605 
606 		return ERR_PTR(result);
607 	}
608 
609 	inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
610 	if (IS_ERR(inode)) {
611 		result = PTR_ERR(inode);
612 		inode = NULL;
613 		goto error;
614 	}
615 
616 	result = v9fs_fid_add(dentry, fid);
617 	if (result < 0)
618 		goto error;
619 
620 	if ((fid->qid.version) && (v9ses->cache))
621 		dentry->d_op = &v9fs_cached_dentry_operations;
622 	else
623 		dentry->d_op = &v9fs_dentry_operations;
624 
625 	d_add(dentry, inode);
626 	return NULL;
627 
628 error:
629 	p9_client_clunk(fid);
630 
631 	return ERR_PTR(result);
632 }
633 
634 /**
635  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
636  * @i:  inode that is being unlinked
637  * @d: dentry that is being unlinked
638  *
639  */
640 
641 static int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
642 {
643 	return v9fs_remove(i, d, 0);
644 }
645 
646 /**
647  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
648  * @i:  inode that is being unlinked
649  * @d: dentry that is being unlinked
650  *
651  */
652 
653 static int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
654 {
655 	return v9fs_remove(i, d, 1);
656 }
657 
658 /**
659  * v9fs_vfs_rename - VFS hook to rename an inode
660  * @old_dir:  old dir inode
661  * @old_dentry: old dentry
662  * @new_dir: new dir inode
663  * @new_dentry: new dentry
664  *
665  */
666 
667 static int
668 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
669 		struct inode *new_dir, struct dentry *new_dentry)
670 {
671 	struct inode *old_inode;
672 	struct v9fs_session_info *v9ses;
673 	struct p9_fid *oldfid;
674 	struct p9_fid *olddirfid;
675 	struct p9_fid *newdirfid;
676 	struct p9_wstat wstat;
677 	int retval;
678 
679 	P9_DPRINTK(P9_DEBUG_VFS, "\n");
680 	retval = 0;
681 	old_inode = old_dentry->d_inode;
682 	v9ses = v9fs_inode2v9ses(old_inode);
683 	oldfid = v9fs_fid_lookup(old_dentry);
684 	if (IS_ERR(oldfid))
685 		return PTR_ERR(oldfid);
686 
687 	olddirfid = v9fs_fid_clone(old_dentry->d_parent);
688 	if (IS_ERR(olddirfid)) {
689 		retval = PTR_ERR(olddirfid);
690 		goto done;
691 	}
692 
693 	newdirfid = v9fs_fid_clone(new_dentry->d_parent);
694 	if (IS_ERR(newdirfid)) {
695 		retval = PTR_ERR(newdirfid);
696 		goto clunk_olddir;
697 	}
698 
699 	/* 9P can only handle file rename in the same directory */
700 	if (memcmp(&olddirfid->qid, &newdirfid->qid, sizeof(newdirfid->qid))) {
701 		P9_DPRINTK(P9_DEBUG_ERROR,
702 				"old dir and new dir are different\n");
703 		retval = -EXDEV;
704 		goto clunk_newdir;
705 	}
706 
707 	v9fs_blank_wstat(&wstat);
708 	wstat.muid = v9ses->uname;
709 	wstat.name = (char *) new_dentry->d_name.name;
710 	retval = p9_client_wstat(oldfid, &wstat);
711 
712 clunk_newdir:
713 	p9_client_clunk(newdirfid);
714 
715 clunk_olddir:
716 	p9_client_clunk(olddirfid);
717 
718 done:
719 	return retval;
720 }
721 
722 /**
723  * v9fs_vfs_getattr - retrieve file metadata
724  * @mnt: mount information
725  * @dentry: file to get attributes on
726  * @stat: metadata structure to populate
727  *
728  */
729 
730 static int
731 v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
732 		 struct kstat *stat)
733 {
734 	int err;
735 	struct v9fs_session_info *v9ses;
736 	struct p9_fid *fid;
737 	struct p9_stat *st;
738 
739 	P9_DPRINTK(P9_DEBUG_VFS, "dentry: %p\n", dentry);
740 	err = -EPERM;
741 	v9ses = v9fs_inode2v9ses(dentry->d_inode);
742 	if (v9ses->cache == CACHE_LOOSE)
743 		return simple_getattr(mnt, dentry, stat);
744 
745 	fid = v9fs_fid_lookup(dentry);
746 	if (IS_ERR(fid))
747 		return PTR_ERR(fid);
748 
749 	st = p9_client_stat(fid);
750 	if (IS_ERR(st))
751 		return PTR_ERR(st);
752 
753 	v9fs_stat2inode(st, dentry->d_inode, dentry->d_inode->i_sb);
754 		generic_fillattr(dentry->d_inode, stat);
755 
756 	kfree(st);
757 	return 0;
758 }
759 
760 /**
761  * v9fs_vfs_setattr - set file metadata
762  * @dentry: file whose metadata to set
763  * @iattr: metadata assignment structure
764  *
765  */
766 
767 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
768 {
769 	int retval;
770 	struct v9fs_session_info *v9ses;
771 	struct p9_fid *fid;
772 	struct p9_wstat wstat;
773 
774 	P9_DPRINTK(P9_DEBUG_VFS, "\n");
775 	retval = -EPERM;
776 	v9ses = v9fs_inode2v9ses(dentry->d_inode);
777 	fid = v9fs_fid_lookup(dentry);
778 	if(IS_ERR(fid))
779 		return PTR_ERR(fid);
780 
781 	v9fs_blank_wstat(&wstat);
782 	if (iattr->ia_valid & ATTR_MODE)
783 		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
784 
785 	if (iattr->ia_valid & ATTR_MTIME)
786 		wstat.mtime = iattr->ia_mtime.tv_sec;
787 
788 	if (iattr->ia_valid & ATTR_ATIME)
789 		wstat.atime = iattr->ia_atime.tv_sec;
790 
791 	if (iattr->ia_valid & ATTR_SIZE)
792 		wstat.length = iattr->ia_size;
793 
794 	if (v9fs_extended(v9ses)) {
795 		if (iattr->ia_valid & ATTR_UID)
796 			wstat.n_uid = iattr->ia_uid;
797 
798 		if (iattr->ia_valid & ATTR_GID)
799 			wstat.n_gid = iattr->ia_gid;
800 	}
801 
802 	retval = p9_client_wstat(fid, &wstat);
803 	if (retval >= 0)
804 		retval = inode_setattr(dentry->d_inode, iattr);
805 
806 	return retval;
807 }
808 
809 /**
810  * v9fs_stat2inode - populate an inode structure with mistat info
811  * @stat: Plan 9 metadata (mistat) structure
812  * @inode: inode to populate
813  * @sb: superblock of filesystem
814  *
815  */
816 
817 void
818 v9fs_stat2inode(struct p9_stat *stat, struct inode *inode,
819 	struct super_block *sb)
820 {
821 	int n;
822 	char ext[32];
823 	struct v9fs_session_info *v9ses = sb->s_fs_info;
824 
825 	inode->i_nlink = 1;
826 
827 	inode->i_atime.tv_sec = stat->atime;
828 	inode->i_mtime.tv_sec = stat->mtime;
829 	inode->i_ctime.tv_sec = stat->mtime;
830 
831 	inode->i_uid = v9ses->dfltuid;
832 	inode->i_gid = v9ses->dfltgid;
833 
834 	if (v9fs_extended(v9ses)) {
835 		inode->i_uid = stat->n_uid;
836 		inode->i_gid = stat->n_gid;
837 	}
838 
839 	inode->i_mode = p9mode2unixmode(v9ses, stat->mode);
840 	if ((S_ISBLK(inode->i_mode)) || (S_ISCHR(inode->i_mode))) {
841 		char type = 0;
842 		int major = -1;
843 		int minor = -1;
844 
845 		n = stat->extension.len;
846 		if (n > sizeof(ext)-1)
847 			n = sizeof(ext)-1;
848 		memmove(ext, stat->extension.str, n);
849 		ext[n] = 0;
850 		sscanf(ext, "%c %u %u", &type, &major, &minor);
851 		switch (type) {
852 		case 'c':
853 			inode->i_mode &= ~S_IFBLK;
854 			inode->i_mode |= S_IFCHR;
855 			break;
856 		case 'b':
857 			break;
858 		default:
859 			P9_DPRINTK(P9_DEBUG_ERROR,
860 				"Unknown special type %c (%.*s)\n", type,
861 				stat->extension.len, stat->extension.str);
862 		};
863 		inode->i_rdev = MKDEV(major, minor);
864 	} else
865 		inode->i_rdev = 0;
866 
867 	inode->i_size = stat->length;
868 
869 	/* not real number of blocks, but 512 byte ones ... */
870 	inode->i_blocks = (inode->i_size + 512 - 1) >> 9;
871 }
872 
873 /**
874  * v9fs_qid2ino - convert qid into inode number
875  * @qid: qid to hash
876  *
877  * BUG: potential for inode number collisions?
878  */
879 
880 ino_t v9fs_qid2ino(struct p9_qid *qid)
881 {
882 	u64 path = qid->path + 2;
883 	ino_t i = 0;
884 
885 	if (sizeof(ino_t) == sizeof(path))
886 		memcpy(&i, &path, sizeof(ino_t));
887 	else
888 		i = (ino_t) (path ^ (path >> 32));
889 
890 	return i;
891 }
892 
893 /**
894  * v9fs_readlink - read a symlink's location (internal version)
895  * @dentry: dentry for symlink
896  * @buffer: buffer to load symlink location into
897  * @buflen: length of buffer
898  *
899  */
900 
901 static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
902 {
903 	int retval;
904 
905 	struct v9fs_session_info *v9ses;
906 	struct p9_fid *fid;
907 	struct p9_stat *st;
908 
909 	P9_DPRINTK(P9_DEBUG_VFS, " %s\n", dentry->d_name.name);
910 	retval = -EPERM;
911 	v9ses = v9fs_inode2v9ses(dentry->d_inode);
912 	fid = v9fs_fid_lookup(dentry);
913 	if (IS_ERR(fid))
914 		return PTR_ERR(fid);
915 
916 	if (!v9fs_extended(v9ses))
917 		return -EBADF;
918 
919 	st = p9_client_stat(fid);
920 	if (IS_ERR(st))
921 		return PTR_ERR(st);
922 
923 	if (!(st->mode & P9_DMSYMLINK)) {
924 		retval = -EINVAL;
925 		goto done;
926 	}
927 
928 	/* copy extension buffer into buffer */
929 	if (st->extension.len < buflen)
930 		buflen = st->extension.len + 1;
931 
932 	memmove(buffer, st->extension.str, buflen - 1);
933 	buffer[buflen-1] = 0;
934 
935 	P9_DPRINTK(P9_DEBUG_VFS,
936 		"%s -> %.*s (%s)\n", dentry->d_name.name, st->extension.len,
937 		st->extension.str, buffer);
938 
939 	retval = buflen;
940 
941 done:
942 	kfree(st);
943 	return retval;
944 }
945 
946 /**
947  * v9fs_vfs_readlink - read a symlink's location
948  * @dentry: dentry for symlink
949  * @buffer: buffer to load symlink location into
950  * @buflen: length of buffer
951  *
952  */
953 
954 static int v9fs_vfs_readlink(struct dentry *dentry, char __user * buffer,
955 			     int buflen)
956 {
957 	int retval;
958 	int ret;
959 	char *link = __getname();
960 
961 	if (unlikely(!link))
962 		return -ENOMEM;
963 
964 	if (buflen > PATH_MAX)
965 		buflen = PATH_MAX;
966 
967 	P9_DPRINTK(P9_DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);
968 
969 	retval = v9fs_readlink(dentry, link, buflen);
970 
971 	if (retval > 0) {
972 		if ((ret = copy_to_user(buffer, link, retval)) != 0) {
973 			P9_DPRINTK(P9_DEBUG_ERROR,
974 					"problem copying to user: %d\n", ret);
975 			retval = ret;
976 		}
977 	}
978 
979 	__putname(link);
980 	return retval;
981 }
982 
983 /**
984  * v9fs_vfs_follow_link - follow a symlink path
985  * @dentry: dentry for symlink
986  * @nd: nameidata
987  *
988  */
989 
990 static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
991 {
992 	int len = 0;
993 	char *link = __getname();
994 
995 	P9_DPRINTK(P9_DEBUG_VFS, "%s n", dentry->d_name.name);
996 
997 	if (!link)
998 		link = ERR_PTR(-ENOMEM);
999 	else {
1000 		len = v9fs_readlink(dentry, link, PATH_MAX);
1001 
1002 		if (len < 0) {
1003 			__putname(link);
1004 			link = ERR_PTR(len);
1005 		} else
1006 			link[len] = 0;
1007 	}
1008 	nd_set_link(nd, link);
1009 
1010 	return NULL;
1011 }
1012 
1013 /**
1014  * v9fs_vfs_put_link - release a symlink path
1015  * @dentry: dentry for symlink
1016  * @nd: nameidata
1017  * @p: unused
1018  *
1019  */
1020 
1021 static void
1022 v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
1023 {
1024 	char *s = nd_get_link(nd);
1025 
1026 	P9_DPRINTK(P9_DEBUG_VFS, " %s %s\n", dentry->d_name.name, s);
1027 	if (!IS_ERR(s))
1028 		__putname(s);
1029 }
1030 
1031 /**
1032  * v9fs_vfs_mkspecial - create a special file
1033  * @dir: inode to create special file in
1034  * @dentry: dentry to create
1035  * @mode: mode to create special file
1036  * @extension: 9p2000.u format extension string representing special file
1037  *
1038  */
1039 
1040 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1041 	int mode, const char *extension)
1042 {
1043 	u32 perm;
1044 	struct v9fs_session_info *v9ses;
1045 	struct p9_fid *fid;
1046 
1047 	v9ses = v9fs_inode2v9ses(dir);
1048 	if (!v9fs_extended(v9ses)) {
1049 		P9_DPRINTK(P9_DEBUG_ERROR, "not extended\n");
1050 		return -EPERM;
1051 	}
1052 
1053 	perm = unixmode2p9mode(v9ses, mode);
1054 	fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1055 								P9_OREAD);
1056 	if (IS_ERR(fid))
1057 		return PTR_ERR(fid);
1058 
1059 	p9_client_clunk(fid);
1060 	return 0;
1061 }
1062 
1063 /**
1064  * v9fs_vfs_symlink - helper function to create symlinks
1065  * @dir: directory inode containing symlink
1066  * @dentry: dentry for symlink
1067  * @symname: symlink data
1068  *
1069  * See Also: 9P2000.u RFC for more information
1070  *
1071  */
1072 
1073 static int
1074 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1075 {
1076 	P9_DPRINTK(P9_DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino,
1077 					dentry->d_name.name, symname);
1078 
1079 	return v9fs_vfs_mkspecial(dir, dentry, S_IFLNK, symname);
1080 }
1081 
1082 /**
1083  * v9fs_vfs_link - create a hardlink
1084  * @old_dentry: dentry for file to link to
1085  * @dir: inode destination for new link
1086  * @dentry: dentry for link
1087  *
1088  */
1089 
1090 static int
1091 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1092 	      struct dentry *dentry)
1093 {
1094 	int retval;
1095 	struct p9_fid *oldfid;
1096 	char *name;
1097 
1098 	P9_DPRINTK(P9_DEBUG_VFS,
1099 		" %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
1100 		old_dentry->d_name.name);
1101 
1102 	oldfid = v9fs_fid_clone(old_dentry);
1103 	if (IS_ERR(oldfid))
1104 		return PTR_ERR(oldfid);
1105 
1106 	name = __getname();
1107 	if (unlikely(!name)) {
1108 		retval = -ENOMEM;
1109 		goto clunk_fid;
1110 	}
1111 
1112 	sprintf(name, "%d\n", oldfid->fid);
1113 	retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1114 	__putname(name);
1115 
1116 clunk_fid:
1117 	p9_client_clunk(oldfid);
1118 	return retval;
1119 }
1120 
1121 /**
1122  * v9fs_vfs_mknod - create a special file
1123  * @dir: inode destination for new link
1124  * @dentry: dentry for file
1125  * @mode: mode for creation
1126  * @rdev: device associated with special file
1127  *
1128  */
1129 
1130 static int
1131 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
1132 {
1133 	int retval;
1134 	char *name;
1135 
1136 	P9_DPRINTK(P9_DEBUG_VFS,
1137 		" %lu,%s mode: %x MAJOR: %u MINOR: %u\n", dir->i_ino,
1138 		dentry->d_name.name, mode, MAJOR(rdev), MINOR(rdev));
1139 
1140 	if (!new_valid_dev(rdev))
1141 		return -EINVAL;
1142 
1143 	name = __getname();
1144 	if (!name)
1145 		return -ENOMEM;
1146 	/* build extension */
1147 	if (S_ISBLK(mode))
1148 		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1149 	else if (S_ISCHR(mode))
1150 		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1151 	else if (S_ISFIFO(mode))
1152 		*name = 0;
1153 	else {
1154 		__putname(name);
1155 		return -EINVAL;
1156 	}
1157 
1158 	retval = v9fs_vfs_mkspecial(dir, dentry, mode, name);
1159 	__putname(name);
1160 
1161 	return retval;
1162 }
1163 
1164 static const struct inode_operations v9fs_dir_inode_operations_ext = {
1165 	.create = v9fs_vfs_create,
1166 	.lookup = v9fs_vfs_lookup,
1167 	.symlink = v9fs_vfs_symlink,
1168 	.link = v9fs_vfs_link,
1169 	.unlink = v9fs_vfs_unlink,
1170 	.mkdir = v9fs_vfs_mkdir,
1171 	.rmdir = v9fs_vfs_rmdir,
1172 	.mknod = v9fs_vfs_mknod,
1173 	.rename = v9fs_vfs_rename,
1174 	.readlink = v9fs_vfs_readlink,
1175 	.getattr = v9fs_vfs_getattr,
1176 	.setattr = v9fs_vfs_setattr,
1177 };
1178 
1179 static const struct inode_operations v9fs_dir_inode_operations = {
1180 	.create = v9fs_vfs_create,
1181 	.lookup = v9fs_vfs_lookup,
1182 	.unlink = v9fs_vfs_unlink,
1183 	.mkdir = v9fs_vfs_mkdir,
1184 	.rmdir = v9fs_vfs_rmdir,
1185 	.mknod = v9fs_vfs_mknod,
1186 	.rename = v9fs_vfs_rename,
1187 	.getattr = v9fs_vfs_getattr,
1188 	.setattr = v9fs_vfs_setattr,
1189 };
1190 
1191 static const struct inode_operations v9fs_file_inode_operations = {
1192 	.getattr = v9fs_vfs_getattr,
1193 	.setattr = v9fs_vfs_setattr,
1194 };
1195 
1196 static const struct inode_operations v9fs_symlink_inode_operations = {
1197 	.readlink = v9fs_vfs_readlink,
1198 	.follow_link = v9fs_vfs_follow_link,
1199 	.put_link = v9fs_vfs_put_link,
1200 	.getattr = v9fs_vfs_getattr,
1201 	.setattr = v9fs_vfs_setattr,
1202 };
1203