xref: /openbmc/linux/fs/9p/vfs_inode.c (revision 367b8112)
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_wstat *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 	P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
421 
422 	err = 0;
423 	ofid = NULL;
424 	fid = NULL;
425 	name = (char *) dentry->d_name.name;
426 	dfid = v9fs_fid_clone(dentry->d_parent);
427 	if (IS_ERR(dfid)) {
428 		err = PTR_ERR(dfid);
429 		P9_DPRINTK(P9_DEBUG_VFS, "fid clone failed %d\n", err);
430 		dfid = NULL;
431 		goto error;
432 	}
433 
434 	/* clone a fid to use for creation */
435 	ofid = p9_client_walk(dfid, 0, NULL, 1);
436 	if (IS_ERR(ofid)) {
437 		err = PTR_ERR(ofid);
438 		P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
439 		ofid = NULL;
440 		goto error;
441 	}
442 
443 	err = p9_client_fcreate(ofid, name, perm, mode, extension);
444 	if (err < 0) {
445 		P9_DPRINTK(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
446 		goto error;
447 	}
448 
449 	/* now walk from the parent so we can get unopened fid */
450 	fid = p9_client_walk(dfid, 1, &name, 0);
451 	if (IS_ERR(fid)) {
452 		err = PTR_ERR(fid);
453 		P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
454 		fid = NULL;
455 		goto error;
456 	} else
457 		dfid = NULL;
458 
459 	/* instantiate inode and assign the unopened fid to the dentry */
460 	inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
461 	if (IS_ERR(inode)) {
462 		err = PTR_ERR(inode);
463 		P9_DPRINTK(P9_DEBUG_VFS, "inode creation failed %d\n", err);
464 		goto error;
465 	}
466 
467 	if (v9ses->cache)
468 		dentry->d_op = &v9fs_cached_dentry_operations;
469 	else
470 		dentry->d_op = &v9fs_dentry_operations;
471 
472 	d_instantiate(dentry, inode);
473 	v9fs_fid_add(dentry, fid);
474 	return ofid;
475 
476 error:
477 	if (dfid)
478 		p9_client_clunk(dfid);
479 
480 	if (ofid)
481 		p9_client_clunk(ofid);
482 
483 	if (fid)
484 		p9_client_clunk(fid);
485 
486 	return ERR_PTR(err);
487 }
488 
489 /**
490  * v9fs_vfs_create - VFS hook to create files
491  * @dir: directory inode that is being created
492  * @dentry:  dentry that is being deleted
493  * @mode: create permissions
494  * @nd: path information
495  *
496  */
497 
498 static int
499 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
500 		struct nameidata *nd)
501 {
502 	int err;
503 	u32 perm;
504 	int flags;
505 	struct v9fs_session_info *v9ses;
506 	struct p9_fid *fid;
507 	struct file *filp;
508 
509 	err = 0;
510 	fid = NULL;
511 	v9ses = v9fs_inode2v9ses(dir);
512 	perm = unixmode2p9mode(v9ses, mode);
513 	if (nd && nd->flags & LOOKUP_OPEN)
514 		flags = nd->intent.open.flags - 1;
515 	else
516 		flags = O_RDWR;
517 
518 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
519 				v9fs_uflags2omode(flags, v9fs_extended(v9ses)));
520 	if (IS_ERR(fid)) {
521 		err = PTR_ERR(fid);
522 		fid = NULL;
523 		goto error;
524 	}
525 
526 	/* if we are opening a file, assign the open fid to the file */
527 	if (nd && nd->flags & LOOKUP_OPEN) {
528 		filp = lookup_instantiate_filp(nd, dentry, v9fs_open_created);
529 		if (IS_ERR(filp)) {
530 			err = PTR_ERR(filp);
531 			goto error;
532 		}
533 
534 		filp->private_data = fid;
535 	} else
536 		p9_client_clunk(fid);
537 
538 	return 0;
539 
540 error:
541 	if (fid)
542 		p9_client_clunk(fid);
543 
544 	return err;
545 }
546 
547 /**
548  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
549  * @dir:  inode that is being unlinked
550  * @dentry: dentry that is being unlinked
551  * @mode: mode for new directory
552  *
553  */
554 
555 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
556 {
557 	int err;
558 	u32 perm;
559 	struct v9fs_session_info *v9ses;
560 	struct p9_fid *fid;
561 
562 	P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
563 	err = 0;
564 	v9ses = v9fs_inode2v9ses(dir);
565 	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
566 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
567 	if (IS_ERR(fid)) {
568 		err = PTR_ERR(fid);
569 		fid = NULL;
570 	}
571 
572 	if (fid)
573 		p9_client_clunk(fid);
574 
575 	return err;
576 }
577 
578 /**
579  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
580  * @dir:  inode that is being walked from
581  * @dentry: dentry that is being walked to?
582  * @nameidata: path data
583  *
584  */
585 
586 static struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
587 				      struct nameidata *nameidata)
588 {
589 	struct super_block *sb;
590 	struct v9fs_session_info *v9ses;
591 	struct p9_fid *dfid, *fid;
592 	struct inode *inode;
593 	char *name;
594 	int result = 0;
595 
596 	P9_DPRINTK(P9_DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
597 		dir, dentry->d_name.name, dentry, nameidata);
598 
599 	sb = dir->i_sb;
600 	v9ses = v9fs_inode2v9ses(dir);
601 	dfid = v9fs_fid_lookup(dentry->d_parent);
602 	if (IS_ERR(dfid))
603 		return ERR_CAST(dfid);
604 
605 	name = (char *) dentry->d_name.name;
606 	fid = p9_client_walk(dfid, 1, &name, 1);
607 	if (IS_ERR(fid)) {
608 		result = PTR_ERR(fid);
609 		if (result == -ENOENT) {
610 			d_add(dentry, NULL);
611 			return NULL;
612 		}
613 
614 		return ERR_PTR(result);
615 	}
616 
617 	inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
618 	if (IS_ERR(inode)) {
619 		result = PTR_ERR(inode);
620 		inode = NULL;
621 		goto error;
622 	}
623 
624 	result = v9fs_fid_add(dentry, fid);
625 	if (result < 0)
626 		goto error;
627 
628 	if ((fid->qid.version) && (v9ses->cache))
629 		dentry->d_op = &v9fs_cached_dentry_operations;
630 	else
631 		dentry->d_op = &v9fs_dentry_operations;
632 
633 	d_add(dentry, inode);
634 	return NULL;
635 
636 error:
637 	p9_client_clunk(fid);
638 
639 	return ERR_PTR(result);
640 }
641 
642 /**
643  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
644  * @i:  inode that is being unlinked
645  * @d: dentry that is being unlinked
646  *
647  */
648 
649 static int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
650 {
651 	return v9fs_remove(i, d, 0);
652 }
653 
654 /**
655  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
656  * @i:  inode that is being unlinked
657  * @d: dentry that is being unlinked
658  *
659  */
660 
661 static int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
662 {
663 	return v9fs_remove(i, d, 1);
664 }
665 
666 /**
667  * v9fs_vfs_rename - VFS hook to rename an inode
668  * @old_dir:  old dir inode
669  * @old_dentry: old dentry
670  * @new_dir: new dir inode
671  * @new_dentry: new dentry
672  *
673  */
674 
675 static int
676 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
677 		struct inode *new_dir, struct dentry *new_dentry)
678 {
679 	struct inode *old_inode;
680 	struct v9fs_session_info *v9ses;
681 	struct p9_fid *oldfid;
682 	struct p9_fid *olddirfid;
683 	struct p9_fid *newdirfid;
684 	struct p9_wstat wstat;
685 	int retval;
686 
687 	P9_DPRINTK(P9_DEBUG_VFS, "\n");
688 	retval = 0;
689 	old_inode = old_dentry->d_inode;
690 	v9ses = v9fs_inode2v9ses(old_inode);
691 	oldfid = v9fs_fid_lookup(old_dentry);
692 	if (IS_ERR(oldfid))
693 		return PTR_ERR(oldfid);
694 
695 	olddirfid = v9fs_fid_clone(old_dentry->d_parent);
696 	if (IS_ERR(olddirfid)) {
697 		retval = PTR_ERR(olddirfid);
698 		goto done;
699 	}
700 
701 	newdirfid = v9fs_fid_clone(new_dentry->d_parent);
702 	if (IS_ERR(newdirfid)) {
703 		retval = PTR_ERR(newdirfid);
704 		goto clunk_olddir;
705 	}
706 
707 	/* 9P can only handle file rename in the same directory */
708 	if (memcmp(&olddirfid->qid, &newdirfid->qid, sizeof(newdirfid->qid))) {
709 		P9_DPRINTK(P9_DEBUG_ERROR,
710 				"old dir and new dir are different\n");
711 		retval = -EXDEV;
712 		goto clunk_newdir;
713 	}
714 
715 	v9fs_blank_wstat(&wstat);
716 	wstat.muid = v9ses->uname;
717 	wstat.name = (char *) new_dentry->d_name.name;
718 	retval = p9_client_wstat(oldfid, &wstat);
719 
720 clunk_newdir:
721 	p9_client_clunk(newdirfid);
722 
723 clunk_olddir:
724 	p9_client_clunk(olddirfid);
725 
726 done:
727 	return retval;
728 }
729 
730 /**
731  * v9fs_vfs_getattr - retrieve file metadata
732  * @mnt: mount information
733  * @dentry: file to get attributes on
734  * @stat: metadata structure to populate
735  *
736  */
737 
738 static int
739 v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
740 		 struct kstat *stat)
741 {
742 	int err;
743 	struct v9fs_session_info *v9ses;
744 	struct p9_fid *fid;
745 	struct p9_wstat *st;
746 
747 	P9_DPRINTK(P9_DEBUG_VFS, "dentry: %p\n", dentry);
748 	err = -EPERM;
749 	v9ses = v9fs_inode2v9ses(dentry->d_inode);
750 	if (v9ses->cache == CACHE_LOOSE)
751 		return simple_getattr(mnt, dentry, stat);
752 
753 	fid = v9fs_fid_lookup(dentry);
754 	if (IS_ERR(fid))
755 		return PTR_ERR(fid);
756 
757 	st = p9_client_stat(fid);
758 	if (IS_ERR(st))
759 		return PTR_ERR(st);
760 
761 	v9fs_stat2inode(st, dentry->d_inode, dentry->d_inode->i_sb);
762 		generic_fillattr(dentry->d_inode, stat);
763 
764 	kfree(st);
765 	return 0;
766 }
767 
768 /**
769  * v9fs_vfs_setattr - set file metadata
770  * @dentry: file whose metadata to set
771  * @iattr: metadata assignment structure
772  *
773  */
774 
775 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
776 {
777 	int retval;
778 	struct v9fs_session_info *v9ses;
779 	struct p9_fid *fid;
780 	struct p9_wstat wstat;
781 
782 	P9_DPRINTK(P9_DEBUG_VFS, "\n");
783 	retval = -EPERM;
784 	v9ses = v9fs_inode2v9ses(dentry->d_inode);
785 	fid = v9fs_fid_lookup(dentry);
786 	if(IS_ERR(fid))
787 		return PTR_ERR(fid);
788 
789 	v9fs_blank_wstat(&wstat);
790 	if (iattr->ia_valid & ATTR_MODE)
791 		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
792 
793 	if (iattr->ia_valid & ATTR_MTIME)
794 		wstat.mtime = iattr->ia_mtime.tv_sec;
795 
796 	if (iattr->ia_valid & ATTR_ATIME)
797 		wstat.atime = iattr->ia_atime.tv_sec;
798 
799 	if (iattr->ia_valid & ATTR_SIZE)
800 		wstat.length = iattr->ia_size;
801 
802 	if (v9fs_extended(v9ses)) {
803 		if (iattr->ia_valid & ATTR_UID)
804 			wstat.n_uid = iattr->ia_uid;
805 
806 		if (iattr->ia_valid & ATTR_GID)
807 			wstat.n_gid = iattr->ia_gid;
808 	}
809 
810 	retval = p9_client_wstat(fid, &wstat);
811 	if (retval >= 0)
812 		retval = inode_setattr(dentry->d_inode, iattr);
813 
814 	return retval;
815 }
816 
817 /**
818  * v9fs_stat2inode - populate an inode structure with mistat info
819  * @stat: Plan 9 metadata (mistat) structure
820  * @inode: inode to populate
821  * @sb: superblock of filesystem
822  *
823  */
824 
825 void
826 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
827 	struct super_block *sb)
828 {
829 	char ext[32];
830 	struct v9fs_session_info *v9ses = sb->s_fs_info;
831 
832 	inode->i_nlink = 1;
833 
834 	inode->i_atime.tv_sec = stat->atime;
835 	inode->i_mtime.tv_sec = stat->mtime;
836 	inode->i_ctime.tv_sec = stat->mtime;
837 
838 	inode->i_uid = v9ses->dfltuid;
839 	inode->i_gid = v9ses->dfltgid;
840 
841 	if (v9fs_extended(v9ses)) {
842 		inode->i_uid = stat->n_uid;
843 		inode->i_gid = stat->n_gid;
844 	}
845 
846 	inode->i_mode = p9mode2unixmode(v9ses, stat->mode);
847 	if ((S_ISBLK(inode->i_mode)) || (S_ISCHR(inode->i_mode))) {
848 		char type = 0;
849 		int major = -1;
850 		int minor = -1;
851 
852 		strncpy(ext, stat->extension, sizeof(ext));
853 		sscanf(ext, "%c %u %u", &type, &major, &minor);
854 		switch (type) {
855 		case 'c':
856 			inode->i_mode &= ~S_IFBLK;
857 			inode->i_mode |= S_IFCHR;
858 			break;
859 		case 'b':
860 			break;
861 		default:
862 			P9_DPRINTK(P9_DEBUG_ERROR,
863 				"Unknown special type %c %s\n", type,
864 				stat->extension);
865 		};
866 		inode->i_rdev = MKDEV(major, minor);
867 		init_special_inode(inode, inode->i_mode, inode->i_rdev);
868 	} else
869 		inode->i_rdev = 0;
870 
871 	inode->i_size = stat->length;
872 
873 	/* not real number of blocks, but 512 byte ones ... */
874 	inode->i_blocks = (inode->i_size + 512 - 1) >> 9;
875 }
876 
877 /**
878  * v9fs_qid2ino - convert qid into inode number
879  * @qid: qid to hash
880  *
881  * BUG: potential for inode number collisions?
882  */
883 
884 ino_t v9fs_qid2ino(struct p9_qid *qid)
885 {
886 	u64 path = qid->path + 2;
887 	ino_t i = 0;
888 
889 	if (sizeof(ino_t) == sizeof(path))
890 		memcpy(&i, &path, sizeof(ino_t));
891 	else
892 		i = (ino_t) (path ^ (path >> 32));
893 
894 	return i;
895 }
896 
897 /**
898  * v9fs_readlink - read a symlink's location (internal version)
899  * @dentry: dentry for symlink
900  * @buffer: buffer to load symlink location into
901  * @buflen: length of buffer
902  *
903  */
904 
905 static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
906 {
907 	int retval;
908 
909 	struct v9fs_session_info *v9ses;
910 	struct p9_fid *fid;
911 	struct p9_wstat *st;
912 
913 	P9_DPRINTK(P9_DEBUG_VFS, " %s\n", dentry->d_name.name);
914 	retval = -EPERM;
915 	v9ses = v9fs_inode2v9ses(dentry->d_inode);
916 	fid = v9fs_fid_lookup(dentry);
917 	if (IS_ERR(fid))
918 		return PTR_ERR(fid);
919 
920 	if (!v9fs_extended(v9ses))
921 		return -EBADF;
922 
923 	st = p9_client_stat(fid);
924 	if (IS_ERR(st))
925 		return PTR_ERR(st);
926 
927 	if (!(st->mode & P9_DMSYMLINK)) {
928 		retval = -EINVAL;
929 		goto done;
930 	}
931 
932 	/* copy extension buffer into buffer */
933 	strncpy(buffer, st->extension, buflen);
934 
935 	P9_DPRINTK(P9_DEBUG_VFS,
936 		"%s -> %s (%s)\n", dentry->d_name.name, st->extension, 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