xref: /linux/fs/9p/vfs_inode.c (revision b0148a98ec5151fec82064d95f11eb9efbc628ea)
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_blocks = 0;
208 		inode->i_rdev = 0;
209 		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
210 		inode->i_mapping->a_ops = &v9fs_addr_operations;
211 
212 		switch (mode & S_IFMT) {
213 		case S_IFIFO:
214 		case S_IFBLK:
215 		case S_IFCHR:
216 		case S_IFSOCK:
217 			if(!v9ses->extended) {
218 				dprintk(DEBUG_ERROR, "special files without extended mode\n");
219 				return ERR_PTR(-EINVAL);
220 			}
221 			init_special_inode(inode, inode->i_mode,
222 					   inode->i_rdev);
223 			break;
224 		case S_IFREG:
225 			inode->i_op = &v9fs_file_inode_operations;
226 			inode->i_fop = &v9fs_file_operations;
227 			break;
228 		case S_IFLNK:
229 			if(!v9ses->extended) {
230 				dprintk(DEBUG_ERROR, "extended modes used w/o 9P2000.u\n");
231 				return ERR_PTR(-EINVAL);
232 			}
233 			inode->i_op = &v9fs_symlink_inode_operations;
234 			break;
235 		case S_IFDIR:
236 			inc_nlink(inode);
237 			if(v9ses->extended)
238 				inode->i_op = &v9fs_dir_inode_operations_ext;
239 			else
240 				inode->i_op = &v9fs_dir_inode_operations;
241 			inode->i_fop = &v9fs_dir_operations;
242 			break;
243 		default:
244 			dprintk(DEBUG_ERROR, "BAD mode 0x%x S_IFMT 0x%x\n",
245 				mode, mode & S_IFMT);
246 			return ERR_PTR(-EINVAL);
247 		}
248 	} else {
249 		eprintk(KERN_WARNING, "Problem allocating inode\n");
250 		return ERR_PTR(-ENOMEM);
251 	}
252 	return inode;
253 }
254 
255 static int
256 v9fs_create(struct v9fs_session_info *v9ses, u32 pfid, char *name, u32 perm,
257 	u8 mode, char *extension, u32 *fidp, struct v9fs_qid *qid, u32 *iounit)
258 {
259 	int fid;
260 	int err;
261 	struct v9fs_fcall *fcall;
262 
263 	fid = v9fs_get_idpool(&v9ses->fidpool);
264 	if (fid < 0) {
265 		eprintk(KERN_WARNING, "no free fids available\n");
266 		return -ENOSPC;
267 	}
268 
269 	err = v9fs_t_walk(v9ses, pfid, fid, NULL, &fcall);
270 	if (err < 0) {
271 		PRINT_FCALL_ERROR("clone error", fcall);
272 		if (fcall && fcall->id == RWALK)
273 			goto clunk_fid;
274 		else
275 			goto put_fid;
276 	}
277 	kfree(fcall);
278 
279 	err = v9fs_t_create(v9ses, fid, name, perm, mode, extension, &fcall);
280 	if (err < 0) {
281 		PRINT_FCALL_ERROR("create fails", fcall);
282 		goto clunk_fid;
283 	}
284 
285 	if (iounit)
286 		*iounit = fcall->params.rcreate.iounit;
287 
288 	if (qid)
289 		*qid = fcall->params.rcreate.qid;
290 
291 	if (fidp)
292 		*fidp = fid;
293 
294 	kfree(fcall);
295 	return 0;
296 
297 clunk_fid:
298 	v9fs_t_clunk(v9ses, fid);
299 	fid = V9FS_NOFID;
300 
301 put_fid:
302 	if (fid != V9FS_NOFID)
303 		v9fs_put_idpool(fid, &v9ses->fidpool);
304 
305 	kfree(fcall);
306 	return err;
307 }
308 
309 static struct v9fs_fid*
310 v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
311 {
312 	int err;
313 	int nfid;
314 	struct v9fs_fid *ret;
315 	struct v9fs_fcall *fcall;
316 
317 	nfid = v9fs_get_idpool(&v9ses->fidpool);
318 	if (nfid < 0) {
319 		eprintk(KERN_WARNING, "no free fids available\n");
320 		return ERR_PTR(-ENOSPC);
321 	}
322 
323 	err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
324 		&fcall);
325 
326 	if (err < 0) {
327 		if (fcall && fcall->id == RWALK)
328 			goto clunk_fid;
329 
330 		PRINT_FCALL_ERROR("walk error", fcall);
331 		v9fs_put_idpool(nfid, &v9ses->fidpool);
332 		goto error;
333 	}
334 
335 	kfree(fcall);
336 	fcall = NULL;
337 	ret = v9fs_fid_create(v9ses, nfid);
338 	if (!ret) {
339 		err = -ENOMEM;
340 		goto clunk_fid;
341 	}
342 
343 	err = v9fs_fid_insert(ret, dentry);
344 	if (err < 0) {
345 		v9fs_fid_destroy(ret);
346 		goto clunk_fid;
347 	}
348 
349 	return ret;
350 
351 clunk_fid:
352 	v9fs_t_clunk(v9ses, nfid);
353 
354 error:
355 	kfree(fcall);
356 	return ERR_PTR(err);
357 }
358 
359 static struct inode *
360 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, u32 fid,
361 	struct super_block *sb)
362 {
363 	int err, umode;
364 	struct inode *ret;
365 	struct v9fs_fcall *fcall;
366 
367 	ret = NULL;
368 	err = v9fs_t_stat(v9ses, fid, &fcall);
369 	if (err) {
370 		PRINT_FCALL_ERROR("stat error", fcall);
371 		goto error;
372 	}
373 
374 	umode = p9mode2unixmode(v9ses, fcall->params.rstat.stat.mode);
375 	ret = v9fs_get_inode(sb, umode);
376 	if (IS_ERR(ret)) {
377 		err = PTR_ERR(ret);
378 		ret = NULL;
379 		goto error;
380 	}
381 
382 	v9fs_stat2inode(&fcall->params.rstat.stat, ret, sb);
383 	kfree(fcall);
384 	return ret;
385 
386 error:
387 	kfree(fcall);
388 	if (ret)
389 		iput(ret);
390 
391 	return ERR_PTR(err);
392 }
393 
394 /**
395  * v9fs_remove - helper function to remove files and directories
396  * @dir: directory inode that is being deleted
397  * @file:  dentry that is being deleted
398  * @rmdir: removing a directory
399  *
400  */
401 
402 static int v9fs_remove(struct inode *dir, struct dentry *file, int rmdir)
403 {
404 	struct v9fs_fcall *fcall = NULL;
405 	struct super_block *sb = NULL;
406 	struct v9fs_session_info *v9ses = NULL;
407 	struct v9fs_fid *v9fid = NULL;
408 	struct inode *file_inode = NULL;
409 	int fid = -1;
410 	int result = 0;
411 
412 	dprintk(DEBUG_VFS, "inode: %p dentry: %p rmdir: %d\n", dir, file,
413 		rmdir);
414 
415 	file_inode = file->d_inode;
416 	sb = file_inode->i_sb;
417 	v9ses = v9fs_inode2v9ses(file_inode);
418 	v9fid = v9fs_fid_lookup(file);
419 	if(IS_ERR(v9fid))
420 		return PTR_ERR(v9fid);
421 
422 	fid = v9fid->fid;
423 	if (fid < 0) {
424 		dprintk(DEBUG_ERROR, "inode #%lu, no fid!\n",
425 			file_inode->i_ino);
426 		return -EBADF;
427 	}
428 
429 	result = v9fs_t_remove(v9ses, fid, &fcall);
430 	if (result < 0) {
431 		PRINT_FCALL_ERROR("remove fails", fcall);
432 		goto Error;
433 	}
434 
435 	v9fs_put_idpool(fid, &v9ses->fidpool);
436 	v9fs_fid_destroy(v9fid);
437 
438 Error:
439 	kfree(fcall);
440 	return result;
441 }
442 
443 static int
444 v9fs_open_created(struct inode *inode, struct file *file)
445 {
446 	return 0;
447 }
448 
449 /**
450  * v9fs_vfs_create - VFS hook to create files
451  * @inode: directory inode that is being deleted
452  * @dentry:  dentry that is being deleted
453  * @mode: create permissions
454  * @nd: path information
455  *
456  */
457 
458 static int
459 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
460 		struct nameidata *nd)
461 {
462 	int err;
463 	u32 fid, perm, iounit;
464 	int flags;
465 	struct v9fs_session_info *v9ses;
466 	struct v9fs_fid *dfid, *vfid, *ffid;
467 	struct inode *inode;
468 	struct v9fs_qid qid;
469 	struct file *filp;
470 
471 	inode = NULL;
472 	vfid = NULL;
473 	v9ses = v9fs_inode2v9ses(dir);
474 	dfid = v9fs_fid_clone(dentry->d_parent);
475 	if(IS_ERR(dfid)) {
476 		err = PTR_ERR(dfid);
477 		goto error;
478 	}
479 
480 	perm = unixmode2p9mode(v9ses, mode);
481 	if (nd && nd->flags & LOOKUP_OPEN)
482 		flags = nd->intent.open.flags - 1;
483 	else
484 		flags = O_RDWR;
485 
486 	err = v9fs_create(v9ses, dfid->fid, (char *) dentry->d_name.name,
487 		perm, v9fs_uflags2omode(flags), NULL, &fid, &qid, &iounit);
488 
489 	if (err)
490 		goto clunk_dfid;
491 
492 	vfid = v9fs_clone_walk(v9ses, dfid->fid, dentry);
493 	v9fs_fid_clunk(v9ses, dfid);
494 	if (IS_ERR(vfid)) {
495 		err = PTR_ERR(vfid);
496 		vfid = NULL;
497 		goto error;
498 	}
499 
500 	inode = v9fs_inode_from_fid(v9ses, vfid->fid, dir->i_sb);
501 	if (IS_ERR(inode)) {
502 		err = PTR_ERR(inode);
503 		inode = NULL;
504 		goto error;
505 	}
506 
507 	dentry->d_op = &v9fs_dentry_operations;
508 	d_instantiate(dentry, inode);
509 
510 	if (nd && nd->flags & LOOKUP_OPEN) {
511 		ffid = v9fs_fid_create(v9ses, fid);
512 		if (!ffid)
513 			return -ENOMEM;
514 
515 		filp = lookup_instantiate_filp(nd, dentry, v9fs_open_created);
516 		if (IS_ERR(filp)) {
517 			v9fs_fid_destroy(ffid);
518 			return PTR_ERR(filp);
519 		}
520 
521 		ffid->rdir_pos = 0;
522 		ffid->rdir_fcall = NULL;
523 		ffid->fidopen = 1;
524 		ffid->iounit = iounit;
525 		ffid->filp = filp;
526 		filp->private_data = ffid;
527 	}
528 
529 	return 0;
530 
531 clunk_dfid:
532 	v9fs_fid_clunk(v9ses, dfid);
533 
534 error:
535 	if (vfid)
536 		v9fs_fid_destroy(vfid);
537 
538 	return err;
539 }
540 
541 /**
542  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
543  * @inode:  inode that is being unlinked
544  * @dentry: dentry that is being unlinked
545  * @mode: mode for new directory
546  *
547  */
548 
549 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
550 {
551 	int err;
552 	u32 fid, perm;
553 	struct v9fs_session_info *v9ses;
554 	struct v9fs_fid *dfid, *vfid;
555 	struct inode *inode;
556 
557 	inode = NULL;
558 	vfid = NULL;
559 	v9ses = v9fs_inode2v9ses(dir);
560 	dfid = v9fs_fid_clone(dentry->d_parent);
561 	if(IS_ERR(dfid)) {
562 		err = PTR_ERR(dfid);
563 		goto error;
564 	}
565 
566 	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
567 
568 	err = v9fs_create(v9ses, dfid->fid, (char *) dentry->d_name.name,
569 		perm, V9FS_OREAD, NULL, &fid, NULL, NULL);
570 
571 	if (err) {
572 		dprintk(DEBUG_ERROR, "create error %d\n", err);
573 		goto clean_up_dfid;
574 	}
575 
576 	vfid = v9fs_clone_walk(v9ses, dfid->fid, dentry);
577 	if (IS_ERR(vfid)) {
578 		err = PTR_ERR(vfid);
579 		vfid = NULL;
580 		goto clean_up_dfid;
581 	}
582 
583 	v9fs_fid_clunk(v9ses, dfid);
584 	inode = v9fs_inode_from_fid(v9ses, vfid->fid, dir->i_sb);
585 	if (IS_ERR(inode)) {
586 		err = PTR_ERR(inode);
587 		inode = NULL;
588 		goto clean_up_fids;
589 	}
590 
591 	dentry->d_op = &v9fs_dentry_operations;
592 	d_instantiate(dentry, inode);
593 	return 0;
594 
595 clean_up_fids:
596 	if (vfid)
597 		v9fs_fid_destroy(vfid);
598 
599 clean_up_dfid:
600 	v9fs_fid_clunk(v9ses, dfid);
601 
602 error:
603 	return err;
604 }
605 
606 /**
607  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
608  * @dir:  inode that is being walked from
609  * @dentry: dentry that is being walked to?
610  * @nameidata: path data
611  *
612  */
613 
614 static struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
615 				      struct nameidata *nameidata)
616 {
617 	struct super_block *sb;
618 	struct v9fs_session_info *v9ses;
619 	struct v9fs_fid *dirfid;
620 	struct v9fs_fid *fid;
621 	struct inode *inode;
622 	struct v9fs_fcall *fcall = NULL;
623 	int dirfidnum = -1;
624 	int newfid = -1;
625 	int result = 0;
626 
627 	dprintk(DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
628 		dir, dentry->d_name.name, dentry, nameidata);
629 
630 	sb = dir->i_sb;
631 	v9ses = v9fs_inode2v9ses(dir);
632 	dentry->d_op = &v9fs_dentry_operations;
633 	dirfid = v9fs_fid_lookup(dentry->d_parent);
634 
635 	if(IS_ERR(dirfid))
636 		return ERR_PTR(PTR_ERR(dirfid));
637 
638 	dirfidnum = dirfid->fid;
639 
640 	newfid = v9fs_get_idpool(&v9ses->fidpool);
641 	if (newfid < 0) {
642 		eprintk(KERN_WARNING, "newfid fails!\n");
643 		result = -ENOSPC;
644 		goto Release_Dirfid;
645 	}
646 
647 	result = v9fs_t_walk(v9ses, dirfidnum, newfid,
648 		(char *)dentry->d_name.name, &fcall);
649 
650 	up(&dirfid->lock);
651 
652 	if (result < 0) {
653 		if (fcall && fcall->id == RWALK)
654 			v9fs_t_clunk(v9ses, newfid);
655 		else
656 			v9fs_put_idpool(newfid, &v9ses->fidpool);
657 
658 		if (result == -ENOENT) {
659 			d_add(dentry, NULL);
660 			dprintk(DEBUG_VFS,
661 				"Return negative dentry %p count %d\n",
662 				dentry, atomic_read(&dentry->d_count));
663 			kfree(fcall);
664 			return NULL;
665 		}
666 		dprintk(DEBUG_ERROR, "walk error:%d\n", result);
667 		goto FreeFcall;
668 	}
669 	kfree(fcall);
670 
671 	result = v9fs_t_stat(v9ses, newfid, &fcall);
672 	if (result < 0) {
673 		dprintk(DEBUG_ERROR, "stat error\n");
674 		goto FreeFcall;
675 	}
676 
677 	inode = v9fs_get_inode(sb, p9mode2unixmode(v9ses,
678 		fcall->params.rstat.stat.mode));
679 
680 	if (IS_ERR(inode) && (PTR_ERR(inode) == -ENOSPC)) {
681 		eprintk(KERN_WARNING, "inode alloc failes, returns %ld\n",
682 			PTR_ERR(inode));
683 
684 		result = -ENOSPC;
685 		goto FreeFcall;
686 	}
687 
688 	inode->i_ino = v9fs_qid2ino(&fcall->params.rstat.stat.qid);
689 
690 	fid = v9fs_fid_create(v9ses, newfid);
691 	if (fid == NULL) {
692 		dprintk(DEBUG_ERROR, "couldn't insert\n");
693 		result = -ENOMEM;
694 		goto FreeFcall;
695 	}
696 
697 	result = v9fs_fid_insert(fid, dentry);
698 	if (result < 0)
699 		goto FreeFcall;
700 
701 	fid->qid = fcall->params.rstat.stat.qid;
702 	v9fs_stat2inode(&fcall->params.rstat.stat, inode, inode->i_sb);
703 
704 	d_add(dentry, inode);
705 	kfree(fcall);
706 
707 	return NULL;
708 
709 Release_Dirfid:
710 	up(&dirfid->lock);
711 
712 FreeFcall:
713 	kfree(fcall);
714 
715 	return ERR_PTR(result);
716 }
717 
718 /**
719  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
720  * @i:  inode that is being unlinked
721  * @d: dentry that is being unlinked
722  *
723  */
724 
725 static int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
726 {
727 	return v9fs_remove(i, d, 0);
728 }
729 
730 /**
731  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
732  * @i:  inode that is being unlinked
733  * @d: dentry that is being unlinked
734  *
735  */
736 
737 static int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
738 {
739 	return v9fs_remove(i, d, 1);
740 }
741 
742 /**
743  * v9fs_vfs_rename - VFS hook to rename an inode
744  * @old_dir:  old dir inode
745  * @old_dentry: old dentry
746  * @new_dir: new dir inode
747  * @new_dentry: new dentry
748  *
749  */
750 
751 static int
752 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
753 		struct inode *new_dir, struct dentry *new_dentry)
754 {
755 	struct inode *old_inode = old_dentry->d_inode;
756 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(old_inode);
757 	struct v9fs_fid *oldfid = v9fs_fid_lookup(old_dentry);
758 	struct v9fs_fid *olddirfid;
759 	struct v9fs_fid *newdirfid;
760 	struct v9fs_wstat wstat;
761 	struct v9fs_fcall *fcall = NULL;
762 	int fid = -1;
763 	int olddirfidnum = -1;
764 	int newdirfidnum = -1;
765 	int retval = 0;
766 
767 	dprintk(DEBUG_VFS, "\n");
768 
769 	if(IS_ERR(oldfid))
770 		return PTR_ERR(oldfid);
771 
772 	olddirfid = v9fs_fid_clone(old_dentry->d_parent);
773 	if(IS_ERR(olddirfid)) {
774 		retval = PTR_ERR(olddirfid);
775 		goto Release_lock;
776 	}
777 
778 	newdirfid = v9fs_fid_clone(new_dentry->d_parent);
779 	if(IS_ERR(newdirfid)) {
780 		retval = PTR_ERR(newdirfid);
781 		goto Clunk_olddir;
782 	}
783 
784 	/* 9P can only handle file rename in the same directory */
785 	if (memcmp(&olddirfid->qid, &newdirfid->qid, sizeof(newdirfid->qid))) {
786 		dprintk(DEBUG_ERROR, "old dir and new dir are different\n");
787 		retval = -EXDEV;
788 		goto Clunk_newdir;
789 	}
790 
791 	fid = oldfid->fid;
792 	olddirfidnum = olddirfid->fid;
793 	newdirfidnum = newdirfid->fid;
794 
795 	if (fid < 0) {
796 		dprintk(DEBUG_ERROR, "no fid for old file #%lu\n",
797 			old_inode->i_ino);
798 		retval = -EBADF;
799 		goto Clunk_newdir;
800 	}
801 
802 	v9fs_blank_wstat(&wstat);
803 	wstat.muid = v9ses->name;
804 	wstat.name = (char *) new_dentry->d_name.name;
805 
806 	retval = v9fs_t_wstat(v9ses, fid, &wstat, &fcall);
807 
808 	if (retval < 0)
809 		PRINT_FCALL_ERROR("wstat error", fcall);
810 
811 	kfree(fcall);
812 
813 Clunk_newdir:
814 	v9fs_fid_clunk(v9ses, newdirfid);
815 
816 Clunk_olddir:
817 	v9fs_fid_clunk(v9ses, olddirfid);
818 
819 Release_lock:
820 	up(&oldfid->lock);
821 
822 	return retval;
823 }
824 
825 /**
826  * v9fs_vfs_getattr - retrieve file metadata
827  * @mnt - mount information
828  * @dentry - file to get attributes on
829  * @stat - metadata structure to populate
830  *
831  */
832 
833 static int
834 v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
835 		 struct kstat *stat)
836 {
837 	struct v9fs_fcall *fcall = NULL;
838 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dentry->d_inode);
839 	struct v9fs_fid *fid = v9fs_fid_clone(dentry);
840 	int err = -EPERM;
841 
842 	dprintk(DEBUG_VFS, "dentry: %p\n", dentry);
843 	if(IS_ERR(fid))
844 		return PTR_ERR(fid);
845 
846 	err = v9fs_t_stat(v9ses, fid->fid, &fcall);
847 
848 	if (err < 0)
849 		dprintk(DEBUG_ERROR, "stat error\n");
850 	else {
851 		v9fs_stat2inode(&fcall->params.rstat.stat, dentry->d_inode,
852 				  dentry->d_inode->i_sb);
853 		generic_fillattr(dentry->d_inode, stat);
854 	}
855 
856 	kfree(fcall);
857 	v9fs_fid_clunk(v9ses, fid);
858 	return err;
859 }
860 
861 /**
862  * v9fs_vfs_setattr - set file metadata
863  * @dentry: file whose metadata to set
864  * @iattr: metadata assignment structure
865  *
866  */
867 
868 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
869 {
870 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dentry->d_inode);
871 	struct v9fs_fid *fid = v9fs_fid_clone(dentry);
872 	struct v9fs_fcall *fcall = NULL;
873 	struct v9fs_wstat wstat;
874 	int res = -EPERM;
875 
876 	dprintk(DEBUG_VFS, "\n");
877 	if(IS_ERR(fid))
878 		return PTR_ERR(fid);
879 
880 	v9fs_blank_wstat(&wstat);
881 	if (iattr->ia_valid & ATTR_MODE)
882 		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
883 
884 	if (iattr->ia_valid & ATTR_MTIME)
885 		wstat.mtime = iattr->ia_mtime.tv_sec;
886 
887 	if (iattr->ia_valid & ATTR_ATIME)
888 		wstat.atime = iattr->ia_atime.tv_sec;
889 
890 	if (iattr->ia_valid & ATTR_SIZE)
891 		wstat.length = iattr->ia_size;
892 
893 	if (v9ses->extended) {
894 		if (iattr->ia_valid & ATTR_UID)
895 			wstat.n_uid = iattr->ia_uid;
896 
897 		if (iattr->ia_valid & ATTR_GID)
898 			wstat.n_gid = iattr->ia_gid;
899 	}
900 
901 	res = v9fs_t_wstat(v9ses, fid->fid, &wstat, &fcall);
902 
903 	if (res < 0)
904 		PRINT_FCALL_ERROR("wstat error", fcall);
905 
906 	kfree(fcall);
907 	if (res >= 0)
908 		res = inode_setattr(dentry->d_inode, iattr);
909 
910 	v9fs_fid_clunk(v9ses, fid);
911 	return res;
912 }
913 
914 /**
915  * v9fs_stat2inode - populate an inode structure with mistat info
916  * @stat: Plan 9 metadata (mistat) structure
917  * @inode: inode to populate
918  * @sb: superblock of filesystem
919  *
920  */
921 
922 void
923 v9fs_stat2inode(struct v9fs_stat *stat, struct inode *inode,
924 	struct super_block *sb)
925 {
926 	int n;
927 	char ext[32];
928 	struct v9fs_session_info *v9ses = sb->s_fs_info;
929 
930 	inode->i_nlink = 1;
931 
932 	inode->i_atime.tv_sec = stat->atime;
933 	inode->i_mtime.tv_sec = stat->mtime;
934 	inode->i_ctime.tv_sec = stat->mtime;
935 
936 	inode->i_uid = v9ses->uid;
937 	inode->i_gid = v9ses->gid;
938 
939 	if (v9ses->extended) {
940 		inode->i_uid = stat->n_uid;
941 		inode->i_gid = stat->n_gid;
942 	}
943 
944 	inode->i_mode = p9mode2unixmode(v9ses, stat->mode);
945 	if ((S_ISBLK(inode->i_mode)) || (S_ISCHR(inode->i_mode))) {
946 		char type = 0;
947 		int major = -1;
948 		int minor = -1;
949 
950 		n = stat->extension.len;
951 		if (n > sizeof(ext)-1)
952 			n = sizeof(ext)-1;
953 		memmove(ext, stat->extension.str, n);
954 		ext[n] = 0;
955 		sscanf(ext, "%c %u %u", &type, &major, &minor);
956 		switch (type) {
957 		case 'c':
958 			inode->i_mode &= ~S_IFBLK;
959 			inode->i_mode |= S_IFCHR;
960 			break;
961 		case 'b':
962 			break;
963 		default:
964 			dprintk(DEBUG_ERROR, "Unknown special type %c (%.*s)\n",
965 				type, stat->extension.len, stat->extension.str);
966 		};
967 		inode->i_rdev = MKDEV(major, minor);
968 	} else
969 		inode->i_rdev = 0;
970 
971 	inode->i_size = stat->length;
972 
973 	inode->i_blocks =
974 	    (inode->i_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
975 }
976 
977 /**
978  * v9fs_qid2ino - convert qid into inode number
979  * @qid: qid to hash
980  *
981  * BUG: potential for inode number collisions?
982  */
983 
984 ino_t v9fs_qid2ino(struct v9fs_qid *qid)
985 {
986 	u64 path = qid->path + 2;
987 	ino_t i = 0;
988 
989 	if (sizeof(ino_t) == sizeof(path))
990 		memcpy(&i, &path, sizeof(ino_t));
991 	else
992 		i = (ino_t) (path ^ (path >> 32));
993 
994 	return i;
995 }
996 
997 /**
998  * v9fs_readlink - read a symlink's location (internal version)
999  * @dentry: dentry for symlink
1000  * @buffer: buffer to load symlink location into
1001  * @buflen: length of buffer
1002  *
1003  */
1004 
1005 static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
1006 {
1007 	int retval = -EPERM;
1008 
1009 	struct v9fs_fcall *fcall = NULL;
1010 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dentry->d_inode);
1011 	struct v9fs_fid *fid = v9fs_fid_clone(dentry);
1012 
1013 	if(IS_ERR(fid))
1014 		return PTR_ERR(fid);
1015 
1016 	if (!v9ses->extended) {
1017 		retval = -EBADF;
1018 		dprintk(DEBUG_ERROR, "not extended\n");
1019 		goto ClunkFid;
1020 	}
1021 
1022 	dprintk(DEBUG_VFS, " %s\n", dentry->d_name.name);
1023 	retval = v9fs_t_stat(v9ses, fid->fid, &fcall);
1024 
1025 	if (retval < 0) {
1026 		dprintk(DEBUG_ERROR, "stat error\n");
1027 		goto FreeFcall;
1028 	}
1029 
1030 	if (!fcall) {
1031 		retval = -EIO;
1032 		goto ClunkFid;
1033 	}
1034 
1035 	if (!(fcall->params.rstat.stat.mode & V9FS_DMSYMLINK)) {
1036 		retval = -EINVAL;
1037 		goto FreeFcall;
1038 	}
1039 
1040 	/* copy extension buffer into buffer */
1041 	if (fcall->params.rstat.stat.extension.len < buflen)
1042 		buflen = fcall->params.rstat.stat.extension.len + 1;
1043 
1044 	memmove(buffer, fcall->params.rstat.stat.extension.str, buflen - 1);
1045 	buffer[buflen-1] = 0;
1046 
1047 	dprintk(DEBUG_ERROR, "%s -> %.*s (%s)\n", dentry->d_name.name, fcall->params.rstat.stat.extension.len,
1048 		fcall->params.rstat.stat.extension.str, buffer);
1049 	retval = buflen;
1050 
1051 FreeFcall:
1052 	kfree(fcall);
1053 
1054 ClunkFid:
1055 	v9fs_fid_clunk(v9ses, fid);
1056 
1057 	return retval;
1058 }
1059 
1060 /**
1061  * v9fs_vfs_readlink - read a symlink's location
1062  * @dentry: dentry for symlink
1063  * @buf: buffer to load symlink location into
1064  * @buflen: length of buffer
1065  *
1066  */
1067 
1068 static int v9fs_vfs_readlink(struct dentry *dentry, char __user * buffer,
1069 			     int buflen)
1070 {
1071 	int retval;
1072 	int ret;
1073 	char *link = __getname();
1074 
1075 	if (unlikely(!link))
1076 		return -ENOMEM;
1077 
1078 	if (buflen > PATH_MAX)
1079 		buflen = PATH_MAX;
1080 
1081 	dprintk(DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);
1082 
1083 	retval = v9fs_readlink(dentry, link, buflen);
1084 
1085 	if (retval > 0) {
1086 		if ((ret = copy_to_user(buffer, link, retval)) != 0) {
1087 			dprintk(DEBUG_ERROR, "problem copying to user: %d\n",
1088 				ret);
1089 			retval = ret;
1090 		}
1091 	}
1092 
1093 	__putname(link);
1094 	return retval;
1095 }
1096 
1097 /**
1098  * v9fs_vfs_follow_link - follow a symlink path
1099  * @dentry: dentry for symlink
1100  * @nd: nameidata
1101  *
1102  */
1103 
1104 static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
1105 {
1106 	int len = 0;
1107 	char *link = __getname();
1108 
1109 	dprintk(DEBUG_VFS, "%s n", dentry->d_name.name);
1110 
1111 	if (!link)
1112 		link = ERR_PTR(-ENOMEM);
1113 	else {
1114 		len = v9fs_readlink(dentry, link, PATH_MAX);
1115 
1116 		if (len < 0) {
1117 			__putname(link);
1118 			link = ERR_PTR(len);
1119 		} else
1120 			link[len] = 0;
1121 	}
1122 	nd_set_link(nd, link);
1123 
1124 	return NULL;
1125 }
1126 
1127 /**
1128  * v9fs_vfs_put_link - release a symlink path
1129  * @dentry: dentry for symlink
1130  * @nd: nameidata
1131  *
1132  */
1133 
1134 static void v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
1135 {
1136 	char *s = nd_get_link(nd);
1137 
1138 	dprintk(DEBUG_VFS, " %s %s\n", dentry->d_name.name, s);
1139 	if (!IS_ERR(s))
1140 		__putname(s);
1141 }
1142 
1143 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1144 	int mode, const char *extension)
1145 {
1146 	int err;
1147 	u32 fid, perm;
1148 	struct v9fs_session_info *v9ses;
1149 	struct v9fs_fid *dfid, *vfid = NULL;
1150 	struct inode *inode = NULL;
1151 
1152 	v9ses = v9fs_inode2v9ses(dir);
1153 	if (!v9ses->extended) {
1154 		dprintk(DEBUG_ERROR, "not extended\n");
1155 		return -EPERM;
1156 	}
1157 
1158 	dfid = v9fs_fid_clone(dentry->d_parent);
1159 	if(IS_ERR(dfid)) {
1160 		err = PTR_ERR(dfid);
1161 		goto error;
1162 	}
1163 
1164 	perm = unixmode2p9mode(v9ses, mode);
1165 
1166 	err = v9fs_create(v9ses, dfid->fid, (char *) dentry->d_name.name,
1167 		perm, V9FS_OREAD, (char *) extension, &fid, NULL, NULL);
1168 
1169 	if (err)
1170 		goto clunk_dfid;
1171 
1172 	err = v9fs_t_clunk(v9ses, fid);
1173 	if (err)
1174 		goto clunk_dfid;
1175 
1176 	vfid = v9fs_clone_walk(v9ses, dfid->fid, dentry);
1177 	if (IS_ERR(vfid)) {
1178 		err = PTR_ERR(vfid);
1179 		vfid = NULL;
1180 		goto clunk_dfid;
1181 	}
1182 
1183 	inode = v9fs_inode_from_fid(v9ses, vfid->fid, dir->i_sb);
1184 	if (IS_ERR(inode)) {
1185 		err = PTR_ERR(inode);
1186 		inode = NULL;
1187 		goto free_vfid;
1188 	}
1189 
1190 	dentry->d_op = &v9fs_dentry_operations;
1191 	d_instantiate(dentry, inode);
1192 	return 0;
1193 
1194 free_vfid:
1195 	v9fs_fid_destroy(vfid);
1196 
1197 clunk_dfid:
1198 	v9fs_fid_clunk(v9ses, dfid);
1199 
1200 error:
1201 	return err;
1202 
1203 }
1204 
1205 /**
1206  * v9fs_vfs_symlink - helper function to create symlinks
1207  * @dir: directory inode containing symlink
1208  * @dentry: dentry for symlink
1209  * @symname: symlink data
1210  *
1211  * See 9P2000.u RFC for more information
1212  *
1213  */
1214 
1215 static int
1216 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1217 {
1218 	dprintk(DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
1219 		symname);
1220 
1221 	return v9fs_vfs_mkspecial(dir, dentry, S_IFLNK, symname);
1222 }
1223 
1224 /**
1225  * v9fs_vfs_link - create a hardlink
1226  * @old_dentry: dentry for file to link to
1227  * @dir: inode destination for new link
1228  * @dentry: dentry for link
1229  *
1230  */
1231 
1232 /* XXX - lots of code dup'd from symlink and creates,
1233  * figure out a better reuse strategy
1234  */
1235 
1236 static int
1237 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1238 	      struct dentry *dentry)
1239 {
1240 	int retval;
1241 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
1242 	struct v9fs_fid *oldfid;
1243 	char *name;
1244 
1245 	dprintk(DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
1246 		old_dentry->d_name.name);
1247 
1248 	oldfid = v9fs_fid_clone(old_dentry);
1249 	if(IS_ERR(oldfid))
1250 		return PTR_ERR(oldfid);
1251 
1252 	name = __getname();
1253 	if (unlikely(!name)) {
1254 		retval = -ENOMEM;
1255 		goto clunk_fid;
1256 	}
1257 
1258 	sprintf(name, "%d\n", oldfid->fid);
1259 	retval = v9fs_vfs_mkspecial(dir, dentry, V9FS_DMLINK, name);
1260 	__putname(name);
1261 
1262 clunk_fid:
1263 	v9fs_fid_clunk(v9ses, oldfid);
1264 	return retval;
1265 }
1266 
1267 /**
1268  * v9fs_vfs_mknod - create a special file
1269  * @dir: inode destination for new link
1270  * @dentry: dentry for file
1271  * @mode: mode for creation
1272  * @dev_t: device associated with special file
1273  *
1274  */
1275 
1276 static int
1277 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
1278 {
1279 	int retval;
1280 	char *name;
1281 
1282 	dprintk(DEBUG_VFS, " %lu,%s mode: %x MAJOR: %u MINOR: %u\n", dir->i_ino,
1283 		dentry->d_name.name, mode, MAJOR(rdev), MINOR(rdev));
1284 
1285 	if (!new_valid_dev(rdev))
1286 		return -EINVAL;
1287 
1288 	name = __getname();
1289 	if (!name)
1290 		return -ENOMEM;
1291 	/* build extension */
1292 	if (S_ISBLK(mode))
1293 		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1294 	else if (S_ISCHR(mode))
1295 		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1296 	else if (S_ISFIFO(mode))
1297 		*name = 0;
1298 	else {
1299 		__putname(name);
1300 		return -EINVAL;
1301 	}
1302 
1303 	retval = v9fs_vfs_mkspecial(dir, dentry, mode, name);
1304 	__putname(name);
1305 
1306 	return retval;
1307 }
1308 
1309 static struct inode_operations v9fs_dir_inode_operations_ext = {
1310 	.create = v9fs_vfs_create,
1311 	.lookup = v9fs_vfs_lookup,
1312 	.symlink = v9fs_vfs_symlink,
1313 	.link = v9fs_vfs_link,
1314 	.unlink = v9fs_vfs_unlink,
1315 	.mkdir = v9fs_vfs_mkdir,
1316 	.rmdir = v9fs_vfs_rmdir,
1317 	.mknod = v9fs_vfs_mknod,
1318 	.rename = v9fs_vfs_rename,
1319 	.readlink = v9fs_vfs_readlink,
1320 	.getattr = v9fs_vfs_getattr,
1321 	.setattr = v9fs_vfs_setattr,
1322 };
1323 
1324 static struct inode_operations v9fs_dir_inode_operations = {
1325 	.create = v9fs_vfs_create,
1326 	.lookup = v9fs_vfs_lookup,
1327 	.unlink = v9fs_vfs_unlink,
1328 	.mkdir = v9fs_vfs_mkdir,
1329 	.rmdir = v9fs_vfs_rmdir,
1330 	.mknod = v9fs_vfs_mknod,
1331 	.rename = v9fs_vfs_rename,
1332 	.getattr = v9fs_vfs_getattr,
1333 	.setattr = v9fs_vfs_setattr,
1334 };
1335 
1336 static struct inode_operations v9fs_file_inode_operations = {
1337 	.getattr = v9fs_vfs_getattr,
1338 	.setattr = v9fs_vfs_setattr,
1339 };
1340 
1341 static struct inode_operations v9fs_symlink_inode_operations = {
1342 	.readlink = v9fs_vfs_readlink,
1343 	.follow_link = v9fs_vfs_follow_link,
1344 	.put_link = v9fs_vfs_put_link,
1345 	.getattr = v9fs_vfs_getattr,
1346 	.setattr = v9fs_vfs_setattr,
1347 };
1348