xref: /linux/fs/9p/vfs_inode.c (revision 6e8331ac6973435b1e7604c30f2ad394035b46e1)
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/smp_lock.h>
34 #include <linux/inet.h>
35 #include <linux/namei.h>
36 #include <linux/idr.h>
37 
38 #include "debug.h"
39 #include "v9fs.h"
40 #include "9p.h"
41 #include "v9fs_vfs.h"
42 #include "fid.h"
43 
44 static struct inode_operations v9fs_dir_inode_operations;
45 static struct inode_operations v9fs_dir_inode_operations_ext;
46 static struct inode_operations v9fs_file_inode_operations;
47 static 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 |= V9FS_DMDIR;
62 	if (v9ses->extended) {
63 		if (S_ISLNK(mode))
64 			res |= V9FS_DMSYMLINK;
65 		if (v9ses->nodev == 0) {
66 			if (S_ISSOCK(mode))
67 				res |= V9FS_DMSOCKET;
68 			if (S_ISFIFO(mode))
69 				res |= V9FS_DMNAMEDPIPE;
70 			if (S_ISBLK(mode))
71 				res |= V9FS_DMDEVICE;
72 			if (S_ISCHR(mode))
73 				res |= V9FS_DMDEVICE;
74 		}
75 
76 		if ((mode & S_ISUID) == S_ISUID)
77 			res |= V9FS_DMSETUID;
78 		if ((mode & S_ISGID) == S_ISGID)
79 			res |= V9FS_DMSETGID;
80 		if ((mode & V9FS_DMLINK))
81 			res |= V9FS_DMLINK;
82 	}
83 
84 	return res;
85 }
86 
87 /**
88  * p9mode2unixmode- convert plan9 mode bits to unix mode bits
89  * @v9ses: v9fs session information
90  * @mode: mode to convert
91  *
92  */
93 
94 static int p9mode2unixmode(struct v9fs_session_info *v9ses, int mode)
95 {
96 	int res;
97 
98 	res = mode & 0777;
99 
100 	if ((mode & V9FS_DMDIR) == V9FS_DMDIR)
101 		res |= S_IFDIR;
102 	else if ((mode & V9FS_DMSYMLINK) && (v9ses->extended))
103 		res |= S_IFLNK;
104 	else if ((mode & V9FS_DMSOCKET) && (v9ses->extended)
105 		 && (v9ses->nodev == 0))
106 		res |= S_IFSOCK;
107 	else if ((mode & V9FS_DMNAMEDPIPE) && (v9ses->extended)
108 		 && (v9ses->nodev == 0))
109 		res |= S_IFIFO;
110 	else if ((mode & V9FS_DMDEVICE) && (v9ses->extended)
111 		 && (v9ses->nodev == 0))
112 		res |= S_IFBLK;
113 	else
114 		res |= S_IFREG;
115 
116 	if (v9ses->extended) {
117 		if ((mode & V9FS_DMSETUID) == V9FS_DMSETUID)
118 			res |= S_ISUID;
119 
120 		if ((mode & V9FS_DMSETGID) == V9FS_DMSETGID)
121 			res |= S_ISGID;
122 	}
123 
124 	return res;
125 }
126 
127 int v9fs_uflags2omode(int uflags)
128 {
129 	int ret;
130 
131 	ret = 0;
132 	switch (uflags&3) {
133 	default:
134 	case O_RDONLY:
135 		ret = V9FS_OREAD;
136 		break;
137 
138 	case O_WRONLY:
139 		ret = V9FS_OWRITE;
140 		break;
141 
142 	case O_RDWR:
143 		ret = V9FS_ORDWR;
144 		break;
145 	}
146 
147 	if (uflags & O_EXCL)
148 		ret |= V9FS_OEXCL;
149 
150 	if (uflags & O_TRUNC)
151 		ret |= V9FS_OTRUNC;
152 
153 	if (uflags & O_APPEND)
154 		ret |= V9FS_OAPPEND;
155 
156 	return ret;
157 }
158 
159 /**
160  * v9fs_blank_wstat - helper function to setup a 9P stat structure
161  * @v9ses: 9P session info (for determining extended mode)
162  * @wstat: structure to initialize
163  *
164  */
165 
166 static void
167 v9fs_blank_wstat(struct v9fs_wstat *wstat)
168 {
169 	wstat->type = ~0;
170 	wstat->dev = ~0;
171 	wstat->qid.type = ~0;
172 	wstat->qid.version = ~0;
173 	*((long long *)&wstat->qid.path) = ~0;
174 	wstat->mode = ~0;
175 	wstat->atime = ~0;
176 	wstat->mtime = ~0;
177 	wstat->length = ~0;
178 	wstat->name = NULL;
179 	wstat->uid = NULL;
180 	wstat->gid = NULL;
181 	wstat->muid = NULL;
182 	wstat->n_uid = ~0;
183 	wstat->n_gid = ~0;
184 	wstat->n_muid = ~0;
185 	wstat->extension = NULL;
186 }
187 
188 /**
189  * v9fs_get_inode - helper function to setup an inode
190  * @sb: superblock
191  * @mode: mode to setup inode with
192  *
193  */
194 
195 struct inode *v9fs_get_inode(struct super_block *sb, int mode)
196 {
197 	struct inode *inode;
198 	struct v9fs_session_info *v9ses = sb->s_fs_info;
199 
200 	dprintk(DEBUG_VFS, "super block: %p mode: %o\n", sb, mode);
201 
202 	inode = new_inode(sb);
203 	if (inode) {
204 		inode->i_mode = mode;
205 		inode->i_uid = current->fsuid;
206 		inode->i_gid = current->fsgid;
207 		inode->i_blksize = sb->s_blocksize;
208 		inode->i_blocks = 0;
209 		inode->i_rdev = 0;
210 		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
211 		inode->i_mapping->a_ops = &v9fs_addr_operations;
212 
213 		switch (mode & S_IFMT) {
214 		case S_IFIFO:
215 		case S_IFBLK:
216 		case S_IFCHR:
217 		case S_IFSOCK:
218 			if(!v9ses->extended) {
219 				dprintk(DEBUG_ERROR, "special files without extended mode\n");
220 				return ERR_PTR(-EINVAL);
221 			}
222 			init_special_inode(inode, inode->i_mode,
223 					   inode->i_rdev);
224 			break;
225 		case S_IFREG:
226 			inode->i_op = &v9fs_file_inode_operations;
227 			inode->i_fop = &v9fs_file_operations;
228 			break;
229 		case S_IFLNK:
230 			if(!v9ses->extended) {
231 				dprintk(DEBUG_ERROR, "extended modes used w/o 9P2000.u\n");
232 				return ERR_PTR(-EINVAL);
233 			}
234 			inode->i_op = &v9fs_symlink_inode_operations;
235 			break;
236 		case S_IFDIR:
237 			inode->i_nlink++;
238 			if(v9ses->extended)
239 				inode->i_op = &v9fs_dir_inode_operations_ext;
240 			else
241 				inode->i_op = &v9fs_dir_inode_operations;
242 			inode->i_fop = &v9fs_dir_operations;
243 			break;
244 		default:
245 			dprintk(DEBUG_ERROR, "BAD mode 0x%x S_IFMT 0x%x\n",
246 				mode, mode & S_IFMT);
247 			return ERR_PTR(-EINVAL);
248 		}
249 	} else {
250 		eprintk(KERN_WARNING, "Problem allocating inode\n");
251 		return ERR_PTR(-ENOMEM);
252 	}
253 	return inode;
254 }
255 
256 static int
257 v9fs_create(struct v9fs_session_info *v9ses, u32 pfid, char *name, u32 perm,
258 	u8 mode, char *extension, u32 *fidp, struct v9fs_qid *qid, u32 *iounit)
259 {
260 	u32 fid;
261 	int err;
262 	struct v9fs_fcall *fcall;
263 
264 	fid = v9fs_get_idpool(&v9ses->fidpool);
265 	if (fid < 0) {
266 		eprintk(KERN_WARNING, "no free fids available\n");
267 		return -ENOSPC;
268 	}
269 
270 	err = v9fs_t_walk(v9ses, pfid, fid, NULL, &fcall);
271 	if (err < 0) {
272 		PRINT_FCALL_ERROR("clone error", fcall);
273 		if (fcall && fcall->id == RWALK)
274 			goto clunk_fid;
275 		else
276 			goto put_fid;
277 	}
278 	kfree(fcall);
279 
280 	err = v9fs_t_create(v9ses, fid, name, perm, mode, extension, &fcall);
281 	if (err < 0) {
282 		PRINT_FCALL_ERROR("create fails", fcall);
283 		goto clunk_fid;
284 	}
285 
286 	if (iounit)
287 		*iounit = fcall->params.rcreate.iounit;
288 
289 	if (qid)
290 		*qid = fcall->params.rcreate.qid;
291 
292 	if (fidp)
293 		*fidp = fid;
294 
295 	kfree(fcall);
296 	return 0;
297 
298 clunk_fid:
299 	v9fs_t_clunk(v9ses, fid);
300 	fid = V9FS_NOFID;
301 
302 put_fid:
303 	if (fid != V9FS_NOFID)
304 		v9fs_put_idpool(fid, &v9ses->fidpool);
305 
306 	kfree(fcall);
307 	return err;
308 }
309 
310 static struct v9fs_fid*
311 v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
312 {
313 	int err;
314 	u32 nfid;
315 	struct v9fs_fid *ret;
316 	struct v9fs_fcall *fcall;
317 
318 	nfid = v9fs_get_idpool(&v9ses->fidpool);
319 	if (nfid < 0) {
320 		eprintk(KERN_WARNING, "no free fids available\n");
321 		return ERR_PTR(-ENOSPC);
322 	}
323 
324 	err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
325 		&fcall);
326 
327 	if (err < 0) {
328 		if (fcall && fcall->id == RWALK)
329 			goto clunk_fid;
330 
331 		PRINT_FCALL_ERROR("walk error", fcall);
332 		v9fs_put_idpool(nfid, &v9ses->fidpool);
333 		goto error;
334 	}
335 
336 	kfree(fcall);
337 	fcall = NULL;
338 	ret = v9fs_fid_create(v9ses, nfid);
339 	if (!ret) {
340 		err = -ENOMEM;
341 		goto clunk_fid;
342 	}
343 
344 	err = v9fs_fid_insert(ret, dentry);
345 	if (err < 0) {
346 		v9fs_fid_destroy(ret);
347 		goto clunk_fid;
348 	}
349 
350 	return ret;
351 
352 clunk_fid:
353 	v9fs_t_clunk(v9ses, nfid);
354 
355 error:
356 	kfree(fcall);
357 	return ERR_PTR(err);
358 }
359 
360 static struct inode *
361 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, u32 fid,
362 	struct super_block *sb)
363 {
364 	int err, umode;
365 	struct inode *ret;
366 	struct v9fs_fcall *fcall;
367 
368 	ret = NULL;
369 	err = v9fs_t_stat(v9ses, fid, &fcall);
370 	if (err) {
371 		PRINT_FCALL_ERROR("stat error", fcall);
372 		goto error;
373 	}
374 
375 	umode = p9mode2unixmode(v9ses, fcall->params.rstat.stat.mode);
376 	ret = v9fs_get_inode(sb, umode);
377 	if (IS_ERR(ret)) {
378 		err = PTR_ERR(ret);
379 		ret = NULL;
380 		goto error;
381 	}
382 
383 	v9fs_stat2inode(&fcall->params.rstat.stat, ret, sb);
384 	kfree(fcall);
385 	return ret;
386 
387 error:
388 	kfree(fcall);
389 	if (ret)
390 		iput(ret);
391 
392 	return ERR_PTR(err);
393 }
394 
395 /**
396  * v9fs_remove - helper function to remove files and directories
397  * @dir: directory inode that is being deleted
398  * @file:  dentry that is being deleted
399  * @rmdir: removing a directory
400  *
401  */
402 
403 static int v9fs_remove(struct inode *dir, struct dentry *file, int rmdir)
404 {
405 	struct v9fs_fcall *fcall = NULL;
406 	struct super_block *sb = NULL;
407 	struct v9fs_session_info *v9ses = NULL;
408 	struct v9fs_fid *v9fid = NULL;
409 	struct inode *file_inode = NULL;
410 	int fid = -1;
411 	int result = 0;
412 
413 	dprintk(DEBUG_VFS, "inode: %p dentry: %p rmdir: %d\n", dir, file,
414 		rmdir);
415 
416 	file_inode = file->d_inode;
417 	sb = file_inode->i_sb;
418 	v9ses = v9fs_inode2v9ses(file_inode);
419 	v9fid = v9fs_fid_lookup(file);
420 
421 	if (!v9fid) {
422 		dprintk(DEBUG_ERROR,
423 			"no v9fs_fid\n");
424 		return -EBADF;
425 	}
426 
427 	fid = v9fid->fid;
428 	if (fid < 0) {
429 		dprintk(DEBUG_ERROR, "inode #%lu, no fid!\n",
430 			file_inode->i_ino);
431 		return -EBADF;
432 	}
433 
434 	result = v9fs_t_remove(v9ses, fid, &fcall);
435 	if (result < 0) {
436 		PRINT_FCALL_ERROR("remove fails", fcall);
437 	}
438 
439 	v9fs_put_idpool(fid, &v9ses->fidpool);
440 	v9fs_fid_destroy(v9fid);
441 
442 	kfree(fcall);
443 	return result;
444 }
445 
446 static int
447 v9fs_open_created(struct inode *inode, struct file *file)
448 {
449 	return 0;
450 }
451 
452 /**
453  * v9fs_vfs_create - VFS hook to create files
454  * @inode: directory inode that is being deleted
455  * @dentry:  dentry that is being deleted
456  * @mode: create permissions
457  * @nd: path information
458  *
459  */
460 
461 static int
462 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
463 		struct nameidata *nd)
464 {
465 	int err;
466 	u32 fid, perm, iounit;
467 	int flags;
468 	struct v9fs_session_info *v9ses;
469 	struct v9fs_fid *dfid, *vfid, *ffid;
470 	struct inode *inode;
471 	struct v9fs_qid qid;
472 	struct file *filp;
473 
474 	inode = NULL;
475 	vfid = NULL;
476 	v9ses = v9fs_inode2v9ses(dir);
477 	dfid = v9fs_fid_lookup(dentry->d_parent);
478 	perm = unixmode2p9mode(v9ses, mode);
479 
480 	if (nd && nd->flags & LOOKUP_OPEN)
481 		flags = nd->intent.open.flags - 1;
482 	else
483 		flags = O_RDWR;
484 
485 	err = v9fs_create(v9ses, dfid->fid, (char *) dentry->d_name.name,
486 		perm, v9fs_uflags2omode(flags), NULL, &fid, &qid, &iounit);
487 
488 	if (err)
489 		goto error;
490 
491 	vfid = v9fs_clone_walk(v9ses, dfid->fid, dentry);
492 	if (IS_ERR(vfid)) {
493 		err = PTR_ERR(vfid);
494 		vfid = NULL;
495 		goto error;
496 	}
497 
498 	inode = v9fs_inode_from_fid(v9ses, vfid->fid, dir->i_sb);
499 	if (IS_ERR(inode)) {
500 		err = PTR_ERR(inode);
501 		inode = NULL;
502 		goto error;
503 	}
504 
505 	dentry->d_op = &v9fs_dentry_operations;
506 	d_instantiate(dentry, inode);
507 
508 	if (nd && nd->flags & LOOKUP_OPEN) {
509 		ffid = v9fs_fid_create(v9ses, fid);
510 		if (!ffid)
511 			return -ENOMEM;
512 
513 		filp = lookup_instantiate_filp(nd, dentry, v9fs_open_created);
514 		if (IS_ERR(filp)) {
515 			v9fs_fid_destroy(ffid);
516 			return PTR_ERR(filp);
517 		}
518 
519 		ffid->rdir_pos = 0;
520 		ffid->rdir_fcall = NULL;
521 		ffid->fidopen = 1;
522 		ffid->iounit = iounit;
523 		ffid->filp = filp;
524 		filp->private_data = ffid;
525 	}
526 
527 	return 0;
528 
529 error:
530 	if (vfid)
531 		v9fs_fid_destroy(vfid);
532 
533 	return err;
534 }
535 
536 /**
537  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
538  * @inode:  inode that is being unlinked
539  * @dentry: dentry that is being unlinked
540  * @mode: mode for new directory
541  *
542  */
543 
544 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
545 {
546 	int err;
547 	u32 fid, perm;
548 	struct v9fs_session_info *v9ses;
549 	struct v9fs_fid *dfid, *vfid;
550 	struct inode *inode;
551 
552 	inode = NULL;
553 	vfid = NULL;
554 	v9ses = v9fs_inode2v9ses(dir);
555 	dfid = v9fs_fid_lookup(dentry->d_parent);
556 	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
557 
558 	err = v9fs_create(v9ses, dfid->fid, (char *) dentry->d_name.name,
559 		perm, V9FS_OREAD, NULL, &fid, NULL, NULL);
560 
561 	if (err) {
562 		dprintk(DEBUG_ERROR, "create error %d\n", err);
563 		goto error;
564 	}
565 
566 	err = v9fs_t_clunk(v9ses, fid);
567 	if (err) {
568 		dprintk(DEBUG_ERROR, "clunk error %d\n", err);
569 		goto error;
570 	}
571 
572 	vfid = v9fs_clone_walk(v9ses, dfid->fid, dentry);
573 	if (IS_ERR(vfid)) {
574 		err = PTR_ERR(vfid);
575 		vfid = NULL;
576 		goto error;
577 	}
578 
579 	inode = v9fs_inode_from_fid(v9ses, vfid->fid, dir->i_sb);
580 	if (IS_ERR(inode)) {
581 		err = PTR_ERR(inode);
582 		inode = NULL;
583 		goto error;
584 	}
585 
586 	dentry->d_op = &v9fs_dentry_operations;
587 	d_instantiate(dentry, inode);
588 	return 0;
589 
590 error:
591 	if (vfid)
592 		v9fs_fid_destroy(vfid);
593 
594 	return err;
595 }
596 
597 /**
598  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
599  * @dir:  inode that is being walked from
600  * @dentry: dentry that is being walked to?
601  * @nameidata: path data
602  *
603  */
604 
605 static struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
606 				      struct nameidata *nameidata)
607 {
608 	struct super_block *sb;
609 	struct v9fs_session_info *v9ses;
610 	struct v9fs_fid *dirfid;
611 	struct v9fs_fid *fid;
612 	struct inode *inode;
613 	struct v9fs_fcall *fcall = NULL;
614 	int dirfidnum = -1;
615 	int newfid = -1;
616 	int result = 0;
617 
618 	dprintk(DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
619 		dir, dentry->d_name.name, dentry, nameidata);
620 
621 	sb = dir->i_sb;
622 	v9ses = v9fs_inode2v9ses(dir);
623 	dentry->d_op = &v9fs_dentry_operations;
624 	dirfid = v9fs_fid_lookup(dentry->d_parent);
625 
626 	if (!dirfid) {
627 		dprintk(DEBUG_ERROR, "no dirfid\n");
628 		return ERR_PTR(-EINVAL);
629 	}
630 
631 	dirfidnum = dirfid->fid;
632 
633 	if (dirfidnum < 0) {
634 		dprintk(DEBUG_ERROR, "no dirfid for inode %p, #%lu\n",
635 			dir, dir->i_ino);
636 		return ERR_PTR(-EBADF);
637 	}
638 
639 	newfid = v9fs_get_idpool(&v9ses->fidpool);
640 	if (newfid < 0) {
641 		eprintk(KERN_WARNING, "newfid fails!\n");
642 		return ERR_PTR(-ENOSPC);
643 	}
644 
645 	result = v9fs_t_walk(v9ses, dirfidnum, newfid,
646 		(char *)dentry->d_name.name, &fcall);
647 
648 	if (result < 0) {
649 		if (fcall && fcall->id == RWALK)
650 			v9fs_t_clunk(v9ses, newfid);
651 		else
652 			v9fs_put_idpool(newfid, &v9ses->fidpool);
653 
654 		if (result == -ENOENT) {
655 			d_add(dentry, NULL);
656 			dprintk(DEBUG_VFS,
657 				"Return negative dentry %p count %d\n",
658 				dentry, atomic_read(&dentry->d_count));
659 			kfree(fcall);
660 			return NULL;
661 		}
662 		dprintk(DEBUG_ERROR, "walk error:%d\n", result);
663 		goto FreeFcall;
664 	}
665 	kfree(fcall);
666 
667 	result = v9fs_t_stat(v9ses, newfid, &fcall);
668 	if (result < 0) {
669 		dprintk(DEBUG_ERROR, "stat error\n");
670 		goto FreeFcall;
671 	}
672 
673 	inode = v9fs_get_inode(sb, p9mode2unixmode(v9ses,
674 		fcall->params.rstat.stat.mode));
675 
676 	if (IS_ERR(inode) && (PTR_ERR(inode) == -ENOSPC)) {
677 		eprintk(KERN_WARNING, "inode alloc failes, returns %ld\n",
678 			PTR_ERR(inode));
679 
680 		result = -ENOSPC;
681 		goto FreeFcall;
682 	}
683 
684 	inode->i_ino = v9fs_qid2ino(&fcall->params.rstat.stat.qid);
685 
686 	fid = v9fs_fid_create(v9ses, newfid);
687 	if (fid == NULL) {
688 		dprintk(DEBUG_ERROR, "couldn't insert\n");
689 		result = -ENOMEM;
690 		goto FreeFcall;
691 	}
692 
693 	result = v9fs_fid_insert(fid, dentry);
694 	if (result < 0)
695 		goto FreeFcall;
696 
697 	fid->qid = fcall->params.rstat.stat.qid;
698 	v9fs_stat2inode(&fcall->params.rstat.stat, inode, inode->i_sb);
699 
700 	d_add(dentry, inode);
701 	kfree(fcall);
702 
703 	return NULL;
704 
705       FreeFcall:
706 	kfree(fcall);
707 	return ERR_PTR(result);
708 }
709 
710 /**
711  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
712  * @i:  inode that is being unlinked
713  * @d: dentry that is being unlinked
714  *
715  */
716 
717 static int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
718 {
719 	return v9fs_remove(i, d, 0);
720 }
721 
722 /**
723  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
724  * @i:  inode that is being unlinked
725  * @d: dentry that is being unlinked
726  *
727  */
728 
729 static int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
730 {
731 	return v9fs_remove(i, d, 1);
732 }
733 
734 /**
735  * v9fs_vfs_rename - VFS hook to rename an inode
736  * @old_dir:  old dir inode
737  * @old_dentry: old dentry
738  * @new_dir: new dir inode
739  * @new_dentry: new dentry
740  *
741  */
742 
743 static int
744 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
745 		struct inode *new_dir, struct dentry *new_dentry)
746 {
747 	struct inode *old_inode = old_dentry->d_inode;
748 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(old_inode);
749 	struct v9fs_fid *oldfid = v9fs_fid_lookup(old_dentry);
750 	struct v9fs_fid *olddirfid =
751 	    v9fs_fid_lookup(old_dentry->d_parent);
752 	struct v9fs_fid *newdirfid =
753 	    v9fs_fid_lookup(new_dentry->d_parent);
754 	struct v9fs_wstat wstat;
755 	struct v9fs_fcall *fcall = NULL;
756 	int fid = -1;
757 	int olddirfidnum = -1;
758 	int newdirfidnum = -1;
759 	int retval = 0;
760 
761 	dprintk(DEBUG_VFS, "\n");
762 
763 	if ((!oldfid) || (!olddirfid) || (!newdirfid)) {
764 		dprintk(DEBUG_ERROR, "problem with arguments\n");
765 		return -EBADF;
766 	}
767 
768 	/* 9P can only handle file rename in the same directory */
769 	if (memcmp(&olddirfid->qid, &newdirfid->qid, sizeof(newdirfid->qid))) {
770 		dprintk(DEBUG_ERROR, "old dir and new dir are different\n");
771 		retval = -EPERM;
772 		goto FreeFcallnBail;
773 	}
774 
775 	fid = oldfid->fid;
776 	olddirfidnum = olddirfid->fid;
777 	newdirfidnum = newdirfid->fid;
778 
779 	if (fid < 0) {
780 		dprintk(DEBUG_ERROR, "no fid for old file #%lu\n",
781 			old_inode->i_ino);
782 		retval = -EBADF;
783 		goto FreeFcallnBail;
784 	}
785 
786 	v9fs_blank_wstat(&wstat);
787 	wstat.muid = v9ses->name;
788 	wstat.name = (char *) new_dentry->d_name.name;
789 
790 	retval = v9fs_t_wstat(v9ses, fid, &wstat, &fcall);
791 
792       FreeFcallnBail:
793 	if (retval < 0)
794 		PRINT_FCALL_ERROR("wstat error", fcall);
795 
796 	kfree(fcall);
797 	return retval;
798 }
799 
800 /**
801  * v9fs_vfs_getattr - retrieve file metadata
802  * @mnt - mount information
803  * @dentry - file to get attributes on
804  * @stat - metadata structure to populate
805  *
806  */
807 
808 static int
809 v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
810 		 struct kstat *stat)
811 {
812 	struct v9fs_fcall *fcall = NULL;
813 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dentry->d_inode);
814 	struct v9fs_fid *fid = v9fs_fid_lookup(dentry);
815 	int err = -EPERM;
816 
817 	dprintk(DEBUG_VFS, "dentry: %p\n", dentry);
818 	if (!fid) {
819 		dprintk(DEBUG_ERROR,
820 			"couldn't find fid associated with dentry\n");
821 		return -EBADF;
822 	}
823 
824 	err = v9fs_t_stat(v9ses, fid->fid, &fcall);
825 
826 	if (err < 0)
827 		dprintk(DEBUG_ERROR, "stat error\n");
828 	else {
829 		v9fs_stat2inode(&fcall->params.rstat.stat, dentry->d_inode,
830 				  dentry->d_inode->i_sb);
831 		generic_fillattr(dentry->d_inode, stat);
832 	}
833 
834 	kfree(fcall);
835 	return err;
836 }
837 
838 /**
839  * v9fs_vfs_setattr - set file metadata
840  * @dentry: file whose metadata to set
841  * @iattr: metadata assignment structure
842  *
843  */
844 
845 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
846 {
847 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dentry->d_inode);
848 	struct v9fs_fid *fid = v9fs_fid_lookup(dentry);
849 	struct v9fs_fcall *fcall = NULL;
850 	struct v9fs_wstat wstat;
851 	int res = -EPERM;
852 
853 	dprintk(DEBUG_VFS, "\n");
854 
855 	if (!fid) {
856 		dprintk(DEBUG_ERROR,
857 			"Couldn't find fid associated with dentry\n");
858 		return -EBADF;
859 	}
860 
861 	v9fs_blank_wstat(&wstat);
862 	if (iattr->ia_valid & ATTR_MODE)
863 		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
864 
865 	if (iattr->ia_valid & ATTR_MTIME)
866 		wstat.mtime = iattr->ia_mtime.tv_sec;
867 
868 	if (iattr->ia_valid & ATTR_ATIME)
869 		wstat.atime = iattr->ia_atime.tv_sec;
870 
871 	if (iattr->ia_valid & ATTR_SIZE)
872 		wstat.length = iattr->ia_size;
873 
874 	if (v9ses->extended) {
875 		if (iattr->ia_valid & ATTR_UID)
876 			wstat.n_uid = iattr->ia_uid;
877 
878 		if (iattr->ia_valid & ATTR_GID)
879 			wstat.n_gid = iattr->ia_gid;
880 	}
881 
882 	res = v9fs_t_wstat(v9ses, fid->fid, &wstat, &fcall);
883 
884 	if (res < 0)
885 		PRINT_FCALL_ERROR("wstat error", fcall);
886 
887 	kfree(fcall);
888 	if (res >= 0)
889 		res = inode_setattr(dentry->d_inode, iattr);
890 
891 	return res;
892 }
893 
894 /**
895  * v9fs_stat2inode - populate an inode structure with mistat info
896  * @stat: Plan 9 metadata (mistat) structure
897  * @inode: inode to populate
898  * @sb: superblock of filesystem
899  *
900  */
901 
902 void
903 v9fs_stat2inode(struct v9fs_stat *stat, struct inode *inode,
904 	struct super_block *sb)
905 {
906 	int n;
907 	char ext[32];
908 	struct v9fs_session_info *v9ses = sb->s_fs_info;
909 
910 	inode->i_nlink = 1;
911 
912 	inode->i_atime.tv_sec = stat->atime;
913 	inode->i_mtime.tv_sec = stat->mtime;
914 	inode->i_ctime.tv_sec = stat->mtime;
915 
916 	inode->i_uid = v9ses->uid;
917 	inode->i_gid = v9ses->gid;
918 
919 	if (v9ses->extended) {
920 		inode->i_uid = stat->n_uid;
921 		inode->i_gid = stat->n_gid;
922 	}
923 
924 	inode->i_mode = p9mode2unixmode(v9ses, stat->mode);
925 	if ((S_ISBLK(inode->i_mode)) || (S_ISCHR(inode->i_mode))) {
926 		char type = 0;
927 		int major = -1;
928 		int minor = -1;
929 
930 		n = stat->extension.len;
931 		if (n > sizeof(ext)-1)
932 			n = sizeof(ext)-1;
933 		memmove(ext, stat->extension.str, n);
934 		ext[n] = 0;
935 		sscanf(ext, "%c %u %u", &type, &major, &minor);
936 		switch (type) {
937 		case 'c':
938 			inode->i_mode &= ~S_IFBLK;
939 			inode->i_mode |= S_IFCHR;
940 			break;
941 		case 'b':
942 			break;
943 		default:
944 			dprintk(DEBUG_ERROR, "Unknown special type %c (%.*s)\n",
945 				type, stat->extension.len, stat->extension.str);
946 		};
947 		inode->i_rdev = MKDEV(major, minor);
948 	} else
949 		inode->i_rdev = 0;
950 
951 	inode->i_size = stat->length;
952 
953 	inode->i_blksize = sb->s_blocksize;
954 	inode->i_blocks =
955 	    (inode->i_size + inode->i_blksize - 1) >> sb->s_blocksize_bits;
956 }
957 
958 /**
959  * v9fs_qid2ino - convert qid into inode number
960  * @qid: qid to hash
961  *
962  * BUG: potential for inode number collisions?
963  */
964 
965 ino_t v9fs_qid2ino(struct v9fs_qid *qid)
966 {
967 	u64 path = qid->path + 2;
968 	ino_t i = 0;
969 
970 	if (sizeof(ino_t) == sizeof(path))
971 		memcpy(&i, &path, sizeof(ino_t));
972 	else
973 		i = (ino_t) (path ^ (path >> 32));
974 
975 	return i;
976 }
977 
978 /**
979  * v9fs_readlink - read a symlink's location (internal version)
980  * @dentry: dentry for symlink
981  * @buffer: buffer to load symlink location into
982  * @buflen: length of buffer
983  *
984  */
985 
986 static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
987 {
988 	int retval = -EPERM;
989 
990 	struct v9fs_fcall *fcall = NULL;
991 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dentry->d_inode);
992 	struct v9fs_fid *fid = v9fs_fid_lookup(dentry);
993 
994 	if (!fid) {
995 		dprintk(DEBUG_ERROR, "could not resolve fid from dentry\n");
996 		retval = -EBADF;
997 		goto FreeFcall;
998 	}
999 
1000 	if (!v9ses->extended) {
1001 		retval = -EBADF;
1002 		dprintk(DEBUG_ERROR, "not extended\n");
1003 		goto FreeFcall;
1004 	}
1005 
1006 	dprintk(DEBUG_VFS, " %s\n", dentry->d_name.name);
1007 	retval = v9fs_t_stat(v9ses, fid->fid, &fcall);
1008 
1009 	if (retval < 0) {
1010 		dprintk(DEBUG_ERROR, "stat error\n");
1011 		goto FreeFcall;
1012 	}
1013 
1014 	if (!fcall)
1015 		return -EIO;
1016 
1017 	if (!(fcall->params.rstat.stat.mode & V9FS_DMSYMLINK)) {
1018 		retval = -EINVAL;
1019 		goto FreeFcall;
1020 	}
1021 
1022 	/* copy extension buffer into buffer */
1023 	if (fcall->params.rstat.stat.extension.len < buflen)
1024 		buflen = fcall->params.rstat.stat.extension.len + 1;
1025 
1026 	memmove(buffer, fcall->params.rstat.stat.extension.str, buflen - 1);
1027 	buffer[buflen-1] = 0;
1028 
1029 	dprintk(DEBUG_ERROR, "%s -> %.*s (%s)\n", dentry->d_name.name, fcall->params.rstat.stat.extension.len,
1030 		fcall->params.rstat.stat.extension.str, buffer);
1031 	retval = buflen;
1032 
1033       FreeFcall:
1034 	kfree(fcall);
1035 
1036 	return retval;
1037 }
1038 
1039 /**
1040  * v9fs_vfs_readlink - read a symlink's location
1041  * @dentry: dentry for symlink
1042  * @buf: buffer to load symlink location into
1043  * @buflen: length of buffer
1044  *
1045  */
1046 
1047 static int v9fs_vfs_readlink(struct dentry *dentry, char __user * buffer,
1048 			     int buflen)
1049 {
1050 	int retval;
1051 	int ret;
1052 	char *link = __getname();
1053 
1054 	if (unlikely(!link))
1055 		return -ENOMEM;
1056 
1057 	if (buflen > PATH_MAX)
1058 		buflen = PATH_MAX;
1059 
1060 	dprintk(DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);
1061 
1062 	retval = v9fs_readlink(dentry, link, buflen);
1063 
1064 	if (retval > 0) {
1065 		if ((ret = copy_to_user(buffer, link, retval)) != 0) {
1066 			dprintk(DEBUG_ERROR, "problem copying to user: %d\n",
1067 				ret);
1068 			retval = ret;
1069 		}
1070 	}
1071 
1072 	__putname(link);
1073 	return retval;
1074 }
1075 
1076 /**
1077  * v9fs_vfs_follow_link - follow a symlink path
1078  * @dentry: dentry for symlink
1079  * @nd: nameidata
1080  *
1081  */
1082 
1083 static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
1084 {
1085 	int len = 0;
1086 	char *link = __getname();
1087 
1088 	dprintk(DEBUG_VFS, "%s n", dentry->d_name.name);
1089 
1090 	if (!link)
1091 		link = ERR_PTR(-ENOMEM);
1092 	else {
1093 		len = v9fs_readlink(dentry, link, PATH_MAX);
1094 
1095 		if (len < 0) {
1096 			__putname(link);
1097 			link = ERR_PTR(len);
1098 		} else
1099 			link[len] = 0;
1100 	}
1101 	nd_set_link(nd, link);
1102 
1103 	return NULL;
1104 }
1105 
1106 /**
1107  * v9fs_vfs_put_link - release a symlink path
1108  * @dentry: dentry for symlink
1109  * @nd: nameidata
1110  *
1111  */
1112 
1113 static void v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
1114 {
1115 	char *s = nd_get_link(nd);
1116 
1117 	dprintk(DEBUG_VFS, " %s %s\n", dentry->d_name.name, s);
1118 	if (!IS_ERR(s))
1119 		__putname(s);
1120 }
1121 
1122 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1123 	int mode, const char *extension)
1124 {
1125 	int err;
1126 	u32 fid, perm;
1127 	struct v9fs_session_info *v9ses;
1128 	struct v9fs_fid *dfid, *vfid;
1129 	struct inode *inode;
1130 
1131 	inode = NULL;
1132 	vfid = NULL;
1133 	v9ses = v9fs_inode2v9ses(dir);
1134 	dfid = v9fs_fid_lookup(dentry->d_parent);
1135 	perm = unixmode2p9mode(v9ses, mode);
1136 
1137 	if (!v9ses->extended) {
1138 		dprintk(DEBUG_ERROR, "not extended\n");
1139 		return -EPERM;
1140 	}
1141 
1142 	err = v9fs_create(v9ses, dfid->fid, (char *) dentry->d_name.name,
1143 		perm, V9FS_OREAD, (char *) extension, &fid, NULL, NULL);
1144 
1145 	if (err)
1146 		goto error;
1147 
1148 	err = v9fs_t_clunk(v9ses, fid);
1149 	if (err)
1150 		goto error;
1151 
1152 	vfid = v9fs_clone_walk(v9ses, dfid->fid, dentry);
1153 	if (IS_ERR(vfid)) {
1154 		err = PTR_ERR(vfid);
1155 		vfid = NULL;
1156 		goto error;
1157 	}
1158 
1159 	inode = v9fs_inode_from_fid(v9ses, vfid->fid, dir->i_sb);
1160 	if (IS_ERR(inode)) {
1161 		err = PTR_ERR(inode);
1162 		inode = NULL;
1163 		goto error;
1164 	}
1165 
1166 	dentry->d_op = &v9fs_dentry_operations;
1167 	d_instantiate(dentry, inode);
1168 	return 0;
1169 
1170 error:
1171 	if (vfid)
1172 		v9fs_fid_destroy(vfid);
1173 
1174 	return err;
1175 
1176 }
1177 
1178 /**
1179  * v9fs_vfs_symlink - helper function to create symlinks
1180  * @dir: directory inode containing symlink
1181  * @dentry: dentry for symlink
1182  * @symname: symlink data
1183  *
1184  * See 9P2000.u RFC for more information
1185  *
1186  */
1187 
1188 static int
1189 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1190 {
1191 	dprintk(DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
1192 		symname);
1193 
1194 	return v9fs_vfs_mkspecial(dir, dentry, S_IFLNK, symname);
1195 }
1196 
1197 /**
1198  * v9fs_vfs_link - create a hardlink
1199  * @old_dentry: dentry for file to link to
1200  * @dir: inode destination for new link
1201  * @dentry: dentry for link
1202  *
1203  */
1204 
1205 /* XXX - lots of code dup'd from symlink and creates,
1206  * figure out a better reuse strategy
1207  */
1208 
1209 static int
1210 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1211 	      struct dentry *dentry)
1212 {
1213 	int retval;
1214 	struct v9fs_fid *oldfid;
1215 	char *name;
1216 
1217 	dprintk(DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
1218 		old_dentry->d_name.name);
1219 
1220 	oldfid = v9fs_fid_lookup(old_dentry);
1221 	if (!oldfid) {
1222 		dprintk(DEBUG_ERROR, "can't find oldfid\n");
1223 		return -EPERM;
1224 	}
1225 
1226 	name = __getname();
1227 	if (unlikely(!name))
1228 		return -ENOMEM;
1229 
1230 	sprintf(name, "%d\n", oldfid->fid);
1231 	retval = v9fs_vfs_mkspecial(dir, dentry, V9FS_DMLINK, name);
1232 	__putname(name);
1233 
1234 	return retval;
1235 }
1236 
1237 /**
1238  * v9fs_vfs_mknod - create a special file
1239  * @dir: inode destination for new link
1240  * @dentry: dentry for file
1241  * @mode: mode for creation
1242  * @dev_t: device associated with special file
1243  *
1244  */
1245 
1246 static int
1247 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
1248 {
1249 	int retval;
1250 	char *name;
1251 
1252 	dprintk(DEBUG_VFS, " %lu,%s mode: %x MAJOR: %u MINOR: %u\n", dir->i_ino,
1253 		dentry->d_name.name, mode, MAJOR(rdev), MINOR(rdev));
1254 
1255 	if (!new_valid_dev(rdev))
1256 		return -EINVAL;
1257 
1258 	name = __getname();
1259 	if (!name)
1260 		return -ENOMEM;
1261 	/* build extension */
1262 	if (S_ISBLK(mode))
1263 		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1264 	else if (S_ISCHR(mode))
1265 		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1266 	else if (S_ISFIFO(mode))
1267 		*name = 0;
1268 	else {
1269 		__putname(name);
1270 		return -EINVAL;
1271 	}
1272 
1273 	retval = v9fs_vfs_mkspecial(dir, dentry, mode, name);
1274 	__putname(name);
1275 
1276 	return retval;
1277 }
1278 
1279 static struct inode_operations v9fs_dir_inode_operations_ext = {
1280 	.create = v9fs_vfs_create,
1281 	.lookup = v9fs_vfs_lookup,
1282 	.symlink = v9fs_vfs_symlink,
1283 	.link = v9fs_vfs_link,
1284 	.unlink = v9fs_vfs_unlink,
1285 	.mkdir = v9fs_vfs_mkdir,
1286 	.rmdir = v9fs_vfs_rmdir,
1287 	.mknod = v9fs_vfs_mknod,
1288 	.rename = v9fs_vfs_rename,
1289 	.readlink = v9fs_vfs_readlink,
1290 	.getattr = v9fs_vfs_getattr,
1291 	.setattr = v9fs_vfs_setattr,
1292 };
1293 
1294 static struct inode_operations v9fs_dir_inode_operations = {
1295 	.create = v9fs_vfs_create,
1296 	.lookup = v9fs_vfs_lookup,
1297 	.unlink = v9fs_vfs_unlink,
1298 	.mkdir = v9fs_vfs_mkdir,
1299 	.rmdir = v9fs_vfs_rmdir,
1300 	.mknod = v9fs_vfs_mknod,
1301 	.rename = v9fs_vfs_rename,
1302 	.getattr = v9fs_vfs_getattr,
1303 	.setattr = v9fs_vfs_setattr,
1304 };
1305 
1306 static struct inode_operations v9fs_file_inode_operations = {
1307 	.getattr = v9fs_vfs_getattr,
1308 	.setattr = v9fs_vfs_setattr,
1309 };
1310 
1311 static struct inode_operations v9fs_symlink_inode_operations = {
1312 	.readlink = v9fs_vfs_readlink,
1313 	.follow_link = v9fs_vfs_follow_link,
1314 	.put_link = v9fs_vfs_put_link,
1315 	.getattr = v9fs_vfs_getattr,
1316 	.setattr = v9fs_vfs_setattr,
1317 };
1318