xref: /openbmc/linux/fs/9p/vfs_inode.c (revision 4800cd83)
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 <linux/slab.h>
38 #include <linux/xattr.h>
39 #include <linux/posix_acl.h>
40 #include <net/9p/9p.h>
41 #include <net/9p/client.h>
42 
43 #include "v9fs.h"
44 #include "v9fs_vfs.h"
45 #include "fid.h"
46 #include "cache.h"
47 #include "xattr.h"
48 #include "acl.h"
49 
50 static const struct inode_operations v9fs_dir_inode_operations;
51 static const struct inode_operations v9fs_dir_inode_operations_dotu;
52 static const struct inode_operations v9fs_file_inode_operations;
53 static const struct inode_operations v9fs_symlink_inode_operations;
54 
55 /**
56  * unixmode2p9mode - convert unix mode bits to plan 9
57  * @v9ses: v9fs session information
58  * @mode: mode to convert
59  *
60  */
61 
62 static int unixmode2p9mode(struct v9fs_session_info *v9ses, int mode)
63 {
64 	int res;
65 	res = mode & 0777;
66 	if (S_ISDIR(mode))
67 		res |= P9_DMDIR;
68 	if (v9fs_proto_dotu(v9ses)) {
69 		if (S_ISLNK(mode))
70 			res |= P9_DMSYMLINK;
71 		if (v9ses->nodev == 0) {
72 			if (S_ISSOCK(mode))
73 				res |= P9_DMSOCKET;
74 			if (S_ISFIFO(mode))
75 				res |= P9_DMNAMEDPIPE;
76 			if (S_ISBLK(mode))
77 				res |= P9_DMDEVICE;
78 			if (S_ISCHR(mode))
79 				res |= P9_DMDEVICE;
80 		}
81 
82 		if ((mode & S_ISUID) == S_ISUID)
83 			res |= P9_DMSETUID;
84 		if ((mode & S_ISGID) == S_ISGID)
85 			res |= P9_DMSETGID;
86 		if ((mode & S_ISVTX) == S_ISVTX)
87 			res |= P9_DMSETVTX;
88 		if ((mode & P9_DMLINK))
89 			res |= P9_DMLINK;
90 	}
91 
92 	return res;
93 }
94 
95 /**
96  * p9mode2unixmode- convert plan9 mode bits to unix mode bits
97  * @v9ses: v9fs session information
98  * @mode: mode to convert
99  *
100  */
101 
102 static int p9mode2unixmode(struct v9fs_session_info *v9ses, int mode)
103 {
104 	int res;
105 
106 	res = mode & 0777;
107 
108 	if ((mode & P9_DMDIR) == P9_DMDIR)
109 		res |= S_IFDIR;
110 	else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
111 		res |= S_IFLNK;
112 	else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
113 		 && (v9ses->nodev == 0))
114 		res |= S_IFSOCK;
115 	else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
116 		 && (v9ses->nodev == 0))
117 		res |= S_IFIFO;
118 	else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
119 		 && (v9ses->nodev == 0))
120 		res |= S_IFBLK;
121 	else
122 		res |= S_IFREG;
123 
124 	if (v9fs_proto_dotu(v9ses)) {
125 		if ((mode & P9_DMSETUID) == P9_DMSETUID)
126 			res |= S_ISUID;
127 
128 		if ((mode & P9_DMSETGID) == P9_DMSETGID)
129 			res |= S_ISGID;
130 
131 		if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
132 			res |= S_ISVTX;
133 	}
134 
135 	return res;
136 }
137 
138 /**
139  * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
140  * @uflags: flags to convert
141  * @extended: if .u extensions are active
142  */
143 
144 int v9fs_uflags2omode(int uflags, int extended)
145 {
146 	int ret;
147 
148 	ret = 0;
149 	switch (uflags&3) {
150 	default:
151 	case O_RDONLY:
152 		ret = P9_OREAD;
153 		break;
154 
155 	case O_WRONLY:
156 		ret = P9_OWRITE;
157 		break;
158 
159 	case O_RDWR:
160 		ret = P9_ORDWR;
161 		break;
162 	}
163 
164 	if (uflags & O_TRUNC)
165 		ret |= P9_OTRUNC;
166 
167 	if (extended) {
168 		if (uflags & O_EXCL)
169 			ret |= P9_OEXCL;
170 
171 		if (uflags & O_APPEND)
172 			ret |= P9_OAPPEND;
173 	}
174 
175 	return ret;
176 }
177 
178 /**
179  * v9fs_blank_wstat - helper function to setup a 9P stat structure
180  * @wstat: structure to initialize
181  *
182  */
183 
184 void
185 v9fs_blank_wstat(struct p9_wstat *wstat)
186 {
187 	wstat->type = ~0;
188 	wstat->dev = ~0;
189 	wstat->qid.type = ~0;
190 	wstat->qid.version = ~0;
191 	*((long long *)&wstat->qid.path) = ~0;
192 	wstat->mode = ~0;
193 	wstat->atime = ~0;
194 	wstat->mtime = ~0;
195 	wstat->length = ~0;
196 	wstat->name = NULL;
197 	wstat->uid = NULL;
198 	wstat->gid = NULL;
199 	wstat->muid = NULL;
200 	wstat->n_uid = ~0;
201 	wstat->n_gid = ~0;
202 	wstat->n_muid = ~0;
203 	wstat->extension = NULL;
204 }
205 
206 #ifdef CONFIG_9P_FSCACHE
207 /**
208  * v9fs_alloc_inode - helper function to allocate an inode
209  * This callback is executed before setting up the inode so that we
210  * can associate a vcookie with each inode.
211  *
212  */
213 
214 struct inode *v9fs_alloc_inode(struct super_block *sb)
215 {
216 	struct v9fs_cookie *vcookie;
217 	vcookie = (struct v9fs_cookie *)kmem_cache_alloc(vcookie_cache,
218 							 GFP_KERNEL);
219 	if (!vcookie)
220 		return NULL;
221 
222 	vcookie->fscache = NULL;
223 	vcookie->qid = NULL;
224 	spin_lock_init(&vcookie->lock);
225 	return &vcookie->inode;
226 }
227 
228 /**
229  * v9fs_destroy_inode - destroy an inode
230  *
231  */
232 
233 static void v9fs_i_callback(struct rcu_head *head)
234 {
235 	struct inode *inode = container_of(head, struct inode, i_rcu);
236 	INIT_LIST_HEAD(&inode->i_dentry);
237 	kmem_cache_free(vcookie_cache, v9fs_inode2cookie(inode));
238 }
239 
240 void v9fs_destroy_inode(struct inode *inode)
241 {
242 	call_rcu(&inode->i_rcu, v9fs_i_callback);
243 }
244 #endif
245 
246 /**
247  * v9fs_get_inode - helper function to setup an inode
248  * @sb: superblock
249  * @mode: mode to setup inode with
250  *
251  */
252 
253 struct inode *v9fs_get_inode(struct super_block *sb, int mode)
254 {
255 	int err;
256 	struct inode *inode;
257 	struct v9fs_session_info *v9ses = sb->s_fs_info;
258 
259 	P9_DPRINTK(P9_DEBUG_VFS, "super block: %p mode: %o\n", sb, mode);
260 
261 	inode = new_inode(sb);
262 	if (!inode) {
263 		P9_EPRINTK(KERN_WARNING, "Problem allocating inode\n");
264 		return ERR_PTR(-ENOMEM);
265 	}
266 
267 	inode_init_owner(inode, NULL, mode);
268 	inode->i_blocks = 0;
269 	inode->i_rdev = 0;
270 	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
271 	inode->i_mapping->a_ops = &v9fs_addr_operations;
272 
273 	switch (mode & S_IFMT) {
274 	case S_IFIFO:
275 	case S_IFBLK:
276 	case S_IFCHR:
277 	case S_IFSOCK:
278 		if (v9fs_proto_dotl(v9ses)) {
279 			inode->i_op = &v9fs_file_inode_operations_dotl;
280 			inode->i_fop = &v9fs_file_operations_dotl;
281 		} else if (v9fs_proto_dotu(v9ses)) {
282 			inode->i_op = &v9fs_file_inode_operations;
283 			inode->i_fop = &v9fs_file_operations;
284 		} else {
285 			P9_DPRINTK(P9_DEBUG_ERROR,
286 				   "special files without extended mode\n");
287 			err = -EINVAL;
288 			goto error;
289 		}
290 		init_special_inode(inode, inode->i_mode, inode->i_rdev);
291 		break;
292 	case S_IFREG:
293 		if (v9fs_proto_dotl(v9ses)) {
294 			inode->i_op = &v9fs_file_inode_operations_dotl;
295 			inode->i_fop = &v9fs_file_operations_dotl;
296 		} else {
297 			inode->i_op = &v9fs_file_inode_operations;
298 			inode->i_fop = &v9fs_file_operations;
299 		}
300 
301 		break;
302 
303 	case S_IFLNK:
304 		if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
305 			P9_DPRINTK(P9_DEBUG_ERROR, "extended modes used with "
306 						"legacy protocol.\n");
307 			err = -EINVAL;
308 			goto error;
309 		}
310 
311 		if (v9fs_proto_dotl(v9ses))
312 			inode->i_op = &v9fs_symlink_inode_operations_dotl;
313 		else
314 			inode->i_op = &v9fs_symlink_inode_operations;
315 
316 		break;
317 	case S_IFDIR:
318 		inc_nlink(inode);
319 		if (v9fs_proto_dotl(v9ses))
320 			inode->i_op = &v9fs_dir_inode_operations_dotl;
321 		else if (v9fs_proto_dotu(v9ses))
322 			inode->i_op = &v9fs_dir_inode_operations_dotu;
323 		else
324 			inode->i_op = &v9fs_dir_inode_operations;
325 
326 		if (v9fs_proto_dotl(v9ses))
327 			inode->i_fop = &v9fs_dir_operations_dotl;
328 		else
329 			inode->i_fop = &v9fs_dir_operations;
330 
331 		break;
332 	default:
333 		P9_DPRINTK(P9_DEBUG_ERROR, "BAD mode 0x%x S_IFMT 0x%x\n",
334 			   mode, mode & S_IFMT);
335 		err = -EINVAL;
336 		goto error;
337 	}
338 
339 	return inode;
340 
341 error:
342 	iput(inode);
343 	return ERR_PTR(err);
344 }
345 
346 /*
347 static struct v9fs_fid*
348 v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
349 {
350 	int err;
351 	int nfid;
352 	struct v9fs_fid *ret;
353 	struct v9fs_fcall *fcall;
354 
355 	nfid = v9fs_get_idpool(&v9ses->fidpool);
356 	if (nfid < 0) {
357 		eprintk(KERN_WARNING, "no free fids available\n");
358 		return ERR_PTR(-ENOSPC);
359 	}
360 
361 	err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
362 		&fcall);
363 
364 	if (err < 0) {
365 		if (fcall && fcall->id == RWALK)
366 			goto clunk_fid;
367 
368 		PRINT_FCALL_ERROR("walk error", fcall);
369 		v9fs_put_idpool(nfid, &v9ses->fidpool);
370 		goto error;
371 	}
372 
373 	kfree(fcall);
374 	fcall = NULL;
375 	ret = v9fs_fid_create(v9ses, nfid);
376 	if (!ret) {
377 		err = -ENOMEM;
378 		goto clunk_fid;
379 	}
380 
381 	err = v9fs_fid_insert(ret, dentry);
382 	if (err < 0) {
383 		v9fs_fid_destroy(ret);
384 		goto clunk_fid;
385 	}
386 
387 	return ret;
388 
389 clunk_fid:
390 	v9fs_t_clunk(v9ses, nfid);
391 
392 error:
393 	kfree(fcall);
394 	return ERR_PTR(err);
395 }
396 */
397 
398 
399 /**
400  * v9fs_clear_inode - release an inode
401  * @inode: inode to release
402  *
403  */
404 void v9fs_evict_inode(struct inode *inode)
405 {
406 	truncate_inode_pages(inode->i_mapping, 0);
407 	end_writeback(inode);
408 	filemap_fdatawrite(inode->i_mapping);
409 
410 #ifdef CONFIG_9P_FSCACHE
411 	v9fs_cache_inode_put_cookie(inode);
412 #endif
413 }
414 
415 struct inode *
416 v9fs_inode(struct v9fs_session_info *v9ses, struct p9_fid *fid,
417 	struct super_block *sb)
418 {
419 	int err, umode;
420 	struct inode *ret = NULL;
421 	struct p9_wstat *st;
422 
423 	st = p9_client_stat(fid);
424 	if (IS_ERR(st))
425 		return ERR_CAST(st);
426 
427 	umode = p9mode2unixmode(v9ses, st->mode);
428 	ret = v9fs_get_inode(sb, umode);
429 	if (IS_ERR(ret)) {
430 		err = PTR_ERR(ret);
431 		goto error;
432 	}
433 
434 	v9fs_stat2inode(st, ret, sb);
435 	ret->i_ino = v9fs_qid2ino(&st->qid);
436 
437 #ifdef CONFIG_9P_FSCACHE
438 	v9fs_vcookie_set_qid(ret, &st->qid);
439 	v9fs_cache_inode_get_cookie(ret);
440 #endif
441 	p9stat_free(st);
442 	kfree(st);
443 	return ret;
444 error:
445 	p9stat_free(st);
446 	kfree(st);
447 	return ERR_PTR(err);
448 }
449 
450 /**
451  * v9fs_remove - helper function to remove files and directories
452  * @dir: directory inode that is being deleted
453  * @file:  dentry that is being deleted
454  * @rmdir: removing a directory
455  *
456  */
457 
458 static int v9fs_remove(struct inode *dir, struct dentry *file, int rmdir)
459 {
460 	int retval;
461 	struct inode *file_inode;
462 	struct p9_fid *v9fid;
463 
464 	P9_DPRINTK(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %d\n", dir, file,
465 		rmdir);
466 
467 	file_inode = file->d_inode;
468 	v9fid = v9fs_fid_clone(file);
469 	if (IS_ERR(v9fid))
470 		return PTR_ERR(v9fid);
471 
472 	retval = p9_client_remove(v9fid);
473 	if (!retval)
474 		drop_nlink(file_inode);
475 	return retval;
476 }
477 
478 /**
479  * v9fs_create - Create a file
480  * @v9ses: session information
481  * @dir: directory that dentry is being created in
482  * @dentry:  dentry that is being created
483  * @extension: 9p2000.u extension string to support devices, etc.
484  * @perm: create permissions
485  * @mode: open mode
486  *
487  */
488 static struct p9_fid *
489 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
490 		struct dentry *dentry, char *extension, u32 perm, u8 mode)
491 {
492 	int err;
493 	char *name;
494 	struct p9_fid *dfid, *ofid, *fid;
495 	struct inode *inode;
496 
497 	P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
498 
499 	err = 0;
500 	ofid = NULL;
501 	fid = NULL;
502 	name = (char *) dentry->d_name.name;
503 	dfid = v9fs_fid_lookup(dentry->d_parent);
504 	if (IS_ERR(dfid)) {
505 		err = PTR_ERR(dfid);
506 		P9_DPRINTK(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
507 		return ERR_PTR(err);
508 	}
509 
510 	/* clone a fid to use for creation */
511 	ofid = p9_client_walk(dfid, 0, NULL, 1);
512 	if (IS_ERR(ofid)) {
513 		err = PTR_ERR(ofid);
514 		P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
515 		return ERR_PTR(err);
516 	}
517 
518 	err = p9_client_fcreate(ofid, name, perm, mode, extension);
519 	if (err < 0) {
520 		P9_DPRINTK(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
521 		goto error;
522 	}
523 
524 	/* now walk from the parent so we can get unopened fid */
525 	fid = p9_client_walk(dfid, 1, &name, 1);
526 	if (IS_ERR(fid)) {
527 		err = PTR_ERR(fid);
528 		P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
529 		fid = NULL;
530 		goto error;
531 	}
532 
533 	/* instantiate inode and assign the unopened fid to the dentry */
534 	inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
535 	if (IS_ERR(inode)) {
536 		err = PTR_ERR(inode);
537 		P9_DPRINTK(P9_DEBUG_VFS, "inode creation failed %d\n", err);
538 		goto error;
539 	}
540 	d_instantiate(dentry, inode);
541 	err = v9fs_fid_add(dentry, fid);
542 	if (err < 0)
543 		goto error;
544 
545 	return ofid;
546 
547 error:
548 	if (ofid)
549 		p9_client_clunk(ofid);
550 
551 	if (fid)
552 		p9_client_clunk(fid);
553 
554 	return ERR_PTR(err);
555 }
556 
557 /**
558  * v9fs_vfs_create - VFS hook to create files
559  * @dir: directory inode that is being created
560  * @dentry:  dentry that is being deleted
561  * @mode: create permissions
562  * @nd: path information
563  *
564  */
565 
566 static int
567 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
568 		struct nameidata *nd)
569 {
570 	int err;
571 	u32 perm;
572 	int flags;
573 	struct v9fs_session_info *v9ses;
574 	struct p9_fid *fid;
575 	struct file *filp;
576 
577 	err = 0;
578 	fid = NULL;
579 	v9ses = v9fs_inode2v9ses(dir);
580 	perm = unixmode2p9mode(v9ses, mode);
581 	if (nd && nd->flags & LOOKUP_OPEN)
582 		flags = nd->intent.open.flags - 1;
583 	else
584 		flags = O_RDWR;
585 
586 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
587 				v9fs_uflags2omode(flags,
588 						v9fs_proto_dotu(v9ses)));
589 	if (IS_ERR(fid)) {
590 		err = PTR_ERR(fid);
591 		fid = NULL;
592 		goto error;
593 	}
594 
595 	/* if we are opening a file, assign the open fid to the file */
596 	if (nd && nd->flags & LOOKUP_OPEN) {
597 		filp = lookup_instantiate_filp(nd, dentry, generic_file_open);
598 		if (IS_ERR(filp)) {
599 			err = PTR_ERR(filp);
600 			goto error;
601 		}
602 
603 		filp->private_data = fid;
604 	} else
605 		p9_client_clunk(fid);
606 
607 	return 0;
608 
609 error:
610 	if (fid)
611 		p9_client_clunk(fid);
612 
613 	return err;
614 }
615 
616 /**
617  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
618  * @dir:  inode that is being unlinked
619  * @dentry: dentry that is being unlinked
620  * @mode: mode for new directory
621  *
622  */
623 
624 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
625 {
626 	int err;
627 	u32 perm;
628 	struct v9fs_session_info *v9ses;
629 	struct p9_fid *fid;
630 
631 	P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
632 	err = 0;
633 	v9ses = v9fs_inode2v9ses(dir);
634 	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
635 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
636 	if (IS_ERR(fid)) {
637 		err = PTR_ERR(fid);
638 		fid = NULL;
639 	}
640 
641 	if (fid)
642 		p9_client_clunk(fid);
643 
644 	return err;
645 }
646 
647 /**
648  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
649  * @dir:  inode that is being walked from
650  * @dentry: dentry that is being walked to?
651  * @nameidata: path data
652  *
653  */
654 
655 struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
656 				      struct nameidata *nameidata)
657 {
658 	struct super_block *sb;
659 	struct v9fs_session_info *v9ses;
660 	struct p9_fid *dfid, *fid;
661 	struct inode *inode;
662 	char *name;
663 	int result = 0;
664 
665 	P9_DPRINTK(P9_DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
666 		dir, dentry->d_name.name, dentry, nameidata);
667 
668 	if (dentry->d_name.len > NAME_MAX)
669 		return ERR_PTR(-ENAMETOOLONG);
670 
671 	sb = dir->i_sb;
672 	v9ses = v9fs_inode2v9ses(dir);
673 	/* We can walk d_parent because we hold the dir->i_mutex */
674 	dfid = v9fs_fid_lookup(dentry->d_parent);
675 	if (IS_ERR(dfid))
676 		return ERR_CAST(dfid);
677 
678 	name = (char *) dentry->d_name.name;
679 	fid = p9_client_walk(dfid, 1, &name, 1);
680 	if (IS_ERR(fid)) {
681 		result = PTR_ERR(fid);
682 		if (result == -ENOENT) {
683 			inode = NULL;
684 			goto inst_out;
685 		}
686 
687 		return ERR_PTR(result);
688 	}
689 
690 	inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
691 	if (IS_ERR(inode)) {
692 		result = PTR_ERR(inode);
693 		inode = NULL;
694 		goto error;
695 	}
696 
697 	result = v9fs_fid_add(dentry, fid);
698 	if (result < 0)
699 		goto error_iput;
700 
701 inst_out:
702 	d_add(dentry, inode);
703 	return NULL;
704 
705 error_iput:
706 	iput(inode);
707 error:
708 	p9_client_clunk(fid);
709 
710 	return ERR_PTR(result);
711 }
712 
713 /**
714  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
715  * @i:  inode that is being unlinked
716  * @d: dentry that is being unlinked
717  *
718  */
719 
720 int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
721 {
722 	return v9fs_remove(i, d, 0);
723 }
724 
725 /**
726  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
727  * @i:  inode that is being unlinked
728  * @d: dentry that is being unlinked
729  *
730  */
731 
732 int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
733 {
734 	return v9fs_remove(i, d, 1);
735 }
736 
737 /**
738  * v9fs_vfs_rename - VFS hook to rename an inode
739  * @old_dir:  old dir inode
740  * @old_dentry: old dentry
741  * @new_dir: new dir inode
742  * @new_dentry: new dentry
743  *
744  */
745 
746 int
747 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
748 		struct inode *new_dir, struct dentry *new_dentry)
749 {
750 	struct inode *old_inode;
751 	struct v9fs_session_info *v9ses;
752 	struct p9_fid *oldfid;
753 	struct p9_fid *olddirfid;
754 	struct p9_fid *newdirfid;
755 	struct p9_wstat wstat;
756 	int retval;
757 
758 	P9_DPRINTK(P9_DEBUG_VFS, "\n");
759 	retval = 0;
760 	old_inode = old_dentry->d_inode;
761 	v9ses = v9fs_inode2v9ses(old_inode);
762 	oldfid = v9fs_fid_lookup(old_dentry);
763 	if (IS_ERR(oldfid))
764 		return PTR_ERR(oldfid);
765 
766 	olddirfid = v9fs_fid_clone(old_dentry->d_parent);
767 	if (IS_ERR(olddirfid)) {
768 		retval = PTR_ERR(olddirfid);
769 		goto done;
770 	}
771 
772 	newdirfid = v9fs_fid_clone(new_dentry->d_parent);
773 	if (IS_ERR(newdirfid)) {
774 		retval = PTR_ERR(newdirfid);
775 		goto clunk_olddir;
776 	}
777 
778 	down_write(&v9ses->rename_sem);
779 	if (v9fs_proto_dotl(v9ses)) {
780 		retval = p9_client_rename(oldfid, newdirfid,
781 					(char *) new_dentry->d_name.name);
782 		if (retval != -ENOSYS)
783 			goto clunk_newdir;
784 	}
785 	if (old_dentry->d_parent != new_dentry->d_parent) {
786 		/*
787 		 * 9P .u can only handle file rename in the same directory
788 		 */
789 
790 		P9_DPRINTK(P9_DEBUG_ERROR,
791 				"old dir and new dir are different\n");
792 		retval = -EXDEV;
793 		goto clunk_newdir;
794 	}
795 	v9fs_blank_wstat(&wstat);
796 	wstat.muid = v9ses->uname;
797 	wstat.name = (char *) new_dentry->d_name.name;
798 	retval = p9_client_wstat(oldfid, &wstat);
799 
800 clunk_newdir:
801 	if (!retval)
802 		/* successful rename */
803 		d_move(old_dentry, new_dentry);
804 	up_write(&v9ses->rename_sem);
805 	p9_client_clunk(newdirfid);
806 
807 clunk_olddir:
808 	p9_client_clunk(olddirfid);
809 
810 done:
811 	return retval;
812 }
813 
814 /**
815  * v9fs_vfs_getattr - retrieve file metadata
816  * @mnt: mount information
817  * @dentry: file to get attributes on
818  * @stat: metadata structure to populate
819  *
820  */
821 
822 static int
823 v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
824 		 struct kstat *stat)
825 {
826 	int err;
827 	struct v9fs_session_info *v9ses;
828 	struct p9_fid *fid;
829 	struct p9_wstat *st;
830 
831 	P9_DPRINTK(P9_DEBUG_VFS, "dentry: %p\n", dentry);
832 	err = -EPERM;
833 	v9ses = v9fs_inode2v9ses(dentry->d_inode);
834 	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
835 		return simple_getattr(mnt, dentry, stat);
836 
837 	fid = v9fs_fid_lookup(dentry);
838 	if (IS_ERR(fid))
839 		return PTR_ERR(fid);
840 
841 	st = p9_client_stat(fid);
842 	if (IS_ERR(st))
843 		return PTR_ERR(st);
844 
845 	v9fs_stat2inode(st, dentry->d_inode, dentry->d_inode->i_sb);
846 		generic_fillattr(dentry->d_inode, stat);
847 
848 	p9stat_free(st);
849 	kfree(st);
850 	return 0;
851 }
852 
853 /**
854  * v9fs_vfs_setattr - set file metadata
855  * @dentry: file whose metadata to set
856  * @iattr: metadata assignment structure
857  *
858  */
859 
860 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
861 {
862 	int retval;
863 	struct v9fs_session_info *v9ses;
864 	struct p9_fid *fid;
865 	struct p9_wstat wstat;
866 
867 	P9_DPRINTK(P9_DEBUG_VFS, "\n");
868 	retval = -EPERM;
869 	v9ses = v9fs_inode2v9ses(dentry->d_inode);
870 	fid = v9fs_fid_lookup(dentry);
871 	if(IS_ERR(fid))
872 		return PTR_ERR(fid);
873 
874 	v9fs_blank_wstat(&wstat);
875 	if (iattr->ia_valid & ATTR_MODE)
876 		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
877 
878 	if (iattr->ia_valid & ATTR_MTIME)
879 		wstat.mtime = iattr->ia_mtime.tv_sec;
880 
881 	if (iattr->ia_valid & ATTR_ATIME)
882 		wstat.atime = iattr->ia_atime.tv_sec;
883 
884 	if (iattr->ia_valid & ATTR_SIZE)
885 		wstat.length = iattr->ia_size;
886 
887 	if (v9fs_proto_dotu(v9ses)) {
888 		if (iattr->ia_valid & ATTR_UID)
889 			wstat.n_uid = iattr->ia_uid;
890 
891 		if (iattr->ia_valid & ATTR_GID)
892 			wstat.n_gid = iattr->ia_gid;
893 	}
894 
895 	retval = p9_client_wstat(fid, &wstat);
896 	if (retval < 0)
897 		return retval;
898 
899 	if ((iattr->ia_valid & ATTR_SIZE) &&
900 	    iattr->ia_size != i_size_read(dentry->d_inode)) {
901 		retval = vmtruncate(dentry->d_inode, iattr->ia_size);
902 		if (retval)
903 			return retval;
904 	}
905 
906 	setattr_copy(dentry->d_inode, iattr);
907 	mark_inode_dirty(dentry->d_inode);
908 	return 0;
909 }
910 
911 /**
912  * v9fs_stat2inode - populate an inode structure with mistat info
913  * @stat: Plan 9 metadata (mistat) structure
914  * @inode: inode to populate
915  * @sb: superblock of filesystem
916  *
917  */
918 
919 void
920 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
921 	struct super_block *sb)
922 {
923 	char ext[32];
924 	char tag_name[14];
925 	unsigned int i_nlink;
926 	struct v9fs_session_info *v9ses = sb->s_fs_info;
927 
928 	inode->i_nlink = 1;
929 
930 	inode->i_atime.tv_sec = stat->atime;
931 	inode->i_mtime.tv_sec = stat->mtime;
932 	inode->i_ctime.tv_sec = stat->mtime;
933 
934 	inode->i_uid = v9ses->dfltuid;
935 	inode->i_gid = v9ses->dfltgid;
936 
937 	if (v9fs_proto_dotu(v9ses)) {
938 		inode->i_uid = stat->n_uid;
939 		inode->i_gid = stat->n_gid;
940 	}
941 	if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
942 		if (v9fs_proto_dotu(v9ses) && (stat->extension[0] != '\0')) {
943 			/*
944 			 * Hadlink support got added later to
945 			 * to the .u extension. So there can be
946 			 * server out there that doesn't support
947 			 * this even with .u extension. So check
948 			 * for non NULL stat->extension
949 			 */
950 			strncpy(ext, stat->extension, sizeof(ext));
951 			/* HARDLINKCOUNT %u */
952 			sscanf(ext, "%13s %u", tag_name, &i_nlink);
953 			if (!strncmp(tag_name, "HARDLINKCOUNT", 13))
954 				inode->i_nlink = i_nlink;
955 		}
956 	}
957 	inode->i_mode = p9mode2unixmode(v9ses, stat->mode);
958 	if ((S_ISBLK(inode->i_mode)) || (S_ISCHR(inode->i_mode))) {
959 		char type = 0;
960 		int major = -1;
961 		int minor = -1;
962 
963 		strncpy(ext, stat->extension, sizeof(ext));
964 		sscanf(ext, "%c %u %u", &type, &major, &minor);
965 		switch (type) {
966 		case 'c':
967 			inode->i_mode &= ~S_IFBLK;
968 			inode->i_mode |= S_IFCHR;
969 			break;
970 		case 'b':
971 			break;
972 		default:
973 			P9_DPRINTK(P9_DEBUG_ERROR,
974 				"Unknown special type %c %s\n", type,
975 				stat->extension);
976 		};
977 		inode->i_rdev = MKDEV(major, minor);
978 		init_special_inode(inode, inode->i_mode, inode->i_rdev);
979 	} else
980 		inode->i_rdev = 0;
981 
982 	i_size_write(inode, stat->length);
983 
984 	/* not real number of blocks, but 512 byte ones ... */
985 	inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
986 }
987 
988 /**
989  * v9fs_qid2ino - convert qid into inode number
990  * @qid: qid to hash
991  *
992  * BUG: potential for inode number collisions?
993  */
994 
995 ino_t v9fs_qid2ino(struct p9_qid *qid)
996 {
997 	u64 path = qid->path + 2;
998 	ino_t i = 0;
999 
1000 	if (sizeof(ino_t) == sizeof(path))
1001 		memcpy(&i, &path, sizeof(ino_t));
1002 	else
1003 		i = (ino_t) (path ^ (path >> 32));
1004 
1005 	return i;
1006 }
1007 
1008 /**
1009  * v9fs_readlink - read a symlink's location (internal version)
1010  * @dentry: dentry for symlink
1011  * @buffer: buffer to load symlink location into
1012  * @buflen: length of buffer
1013  *
1014  */
1015 
1016 static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
1017 {
1018 	int retval;
1019 
1020 	struct v9fs_session_info *v9ses;
1021 	struct p9_fid *fid;
1022 	struct p9_wstat *st;
1023 
1024 	P9_DPRINTK(P9_DEBUG_VFS, " %s\n", dentry->d_name.name);
1025 	retval = -EPERM;
1026 	v9ses = v9fs_inode2v9ses(dentry->d_inode);
1027 	fid = v9fs_fid_lookup(dentry);
1028 	if (IS_ERR(fid))
1029 		return PTR_ERR(fid);
1030 
1031 	if (!v9fs_proto_dotu(v9ses))
1032 		return -EBADF;
1033 
1034 	st = p9_client_stat(fid);
1035 	if (IS_ERR(st))
1036 		return PTR_ERR(st);
1037 
1038 	if (!(st->mode & P9_DMSYMLINK)) {
1039 		retval = -EINVAL;
1040 		goto done;
1041 	}
1042 
1043 	/* copy extension buffer into buffer */
1044 	strncpy(buffer, st->extension, buflen);
1045 
1046 	P9_DPRINTK(P9_DEBUG_VFS,
1047 		"%s -> %s (%s)\n", dentry->d_name.name, st->extension, buffer);
1048 
1049 	retval = strnlen(buffer, buflen);
1050 done:
1051 	p9stat_free(st);
1052 	kfree(st);
1053 	return retval;
1054 }
1055 
1056 /**
1057  * v9fs_vfs_follow_link - follow a symlink path
1058  * @dentry: dentry for symlink
1059  * @nd: nameidata
1060  *
1061  */
1062 
1063 static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
1064 {
1065 	int len = 0;
1066 	char *link = __getname();
1067 
1068 	P9_DPRINTK(P9_DEBUG_VFS, "%s n", dentry->d_name.name);
1069 
1070 	if (!link)
1071 		link = ERR_PTR(-ENOMEM);
1072 	else {
1073 		len = v9fs_readlink(dentry, link, PATH_MAX);
1074 
1075 		if (len < 0) {
1076 			__putname(link);
1077 			link = ERR_PTR(len);
1078 		} else
1079 			link[min(len, PATH_MAX-1)] = 0;
1080 	}
1081 	nd_set_link(nd, link);
1082 
1083 	return NULL;
1084 }
1085 
1086 /**
1087  * v9fs_vfs_put_link - release a symlink path
1088  * @dentry: dentry for symlink
1089  * @nd: nameidata
1090  * @p: unused
1091  *
1092  */
1093 
1094 void
1095 v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
1096 {
1097 	char *s = nd_get_link(nd);
1098 
1099 	P9_DPRINTK(P9_DEBUG_VFS, " %s %s\n", dentry->d_name.name,
1100 		IS_ERR(s) ? "<error>" : s);
1101 	if (!IS_ERR(s))
1102 		__putname(s);
1103 }
1104 
1105 /**
1106  * v9fs_vfs_mkspecial - create a special file
1107  * @dir: inode to create special file in
1108  * @dentry: dentry to create
1109  * @mode: mode to create special file
1110  * @extension: 9p2000.u format extension string representing special file
1111  *
1112  */
1113 
1114 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1115 	int mode, const char *extension)
1116 {
1117 	u32 perm;
1118 	struct v9fs_session_info *v9ses;
1119 	struct p9_fid *fid;
1120 
1121 	v9ses = v9fs_inode2v9ses(dir);
1122 	if (!v9fs_proto_dotu(v9ses)) {
1123 		P9_DPRINTK(P9_DEBUG_ERROR, "not extended\n");
1124 		return -EPERM;
1125 	}
1126 
1127 	perm = unixmode2p9mode(v9ses, mode);
1128 	fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1129 								P9_OREAD);
1130 	if (IS_ERR(fid))
1131 		return PTR_ERR(fid);
1132 
1133 	p9_client_clunk(fid);
1134 	return 0;
1135 }
1136 
1137 /**
1138  * v9fs_vfs_symlink - helper function to create symlinks
1139  * @dir: directory inode containing symlink
1140  * @dentry: dentry for symlink
1141  * @symname: symlink data
1142  *
1143  * See Also: 9P2000.u RFC for more information
1144  *
1145  */
1146 
1147 static int
1148 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1149 {
1150 	P9_DPRINTK(P9_DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino,
1151 					dentry->d_name.name, symname);
1152 
1153 	return v9fs_vfs_mkspecial(dir, dentry, S_IFLNK, symname);
1154 }
1155 
1156 /**
1157  * v9fs_vfs_link - create a hardlink
1158  * @old_dentry: dentry for file to link to
1159  * @dir: inode destination for new link
1160  * @dentry: dentry for link
1161  *
1162  */
1163 
1164 static int
1165 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1166 	      struct dentry *dentry)
1167 {
1168 	int retval;
1169 	struct p9_fid *oldfid;
1170 	char *name;
1171 
1172 	P9_DPRINTK(P9_DEBUG_VFS,
1173 		" %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
1174 		old_dentry->d_name.name);
1175 
1176 	oldfid = v9fs_fid_clone(old_dentry);
1177 	if (IS_ERR(oldfid))
1178 		return PTR_ERR(oldfid);
1179 
1180 	name = __getname();
1181 	if (unlikely(!name)) {
1182 		retval = -ENOMEM;
1183 		goto clunk_fid;
1184 	}
1185 
1186 	sprintf(name, "%d\n", oldfid->fid);
1187 	retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1188 	__putname(name);
1189 
1190 clunk_fid:
1191 	p9_client_clunk(oldfid);
1192 	return retval;
1193 }
1194 
1195 /**
1196  * v9fs_vfs_mknod - create a special file
1197  * @dir: inode destination for new link
1198  * @dentry: dentry for file
1199  * @mode: mode for creation
1200  * @rdev: device associated with special file
1201  *
1202  */
1203 
1204 static int
1205 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
1206 {
1207 	int retval;
1208 	char *name;
1209 
1210 	P9_DPRINTK(P9_DEBUG_VFS,
1211 		" %lu,%s mode: %x MAJOR: %u MINOR: %u\n", dir->i_ino,
1212 		dentry->d_name.name, mode, MAJOR(rdev), MINOR(rdev));
1213 
1214 	if (!new_valid_dev(rdev))
1215 		return -EINVAL;
1216 
1217 	name = __getname();
1218 	if (!name)
1219 		return -ENOMEM;
1220 	/* build extension */
1221 	if (S_ISBLK(mode))
1222 		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1223 	else if (S_ISCHR(mode))
1224 		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1225 	else if (S_ISFIFO(mode))
1226 		*name = 0;
1227 	else if (S_ISSOCK(mode))
1228 		*name = 0;
1229 	else {
1230 		__putname(name);
1231 		return -EINVAL;
1232 	}
1233 
1234 	retval = v9fs_vfs_mkspecial(dir, dentry, mode, name);
1235 	__putname(name);
1236 
1237 	return retval;
1238 }
1239 
1240 static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1241 	.create = v9fs_vfs_create,
1242 	.lookup = v9fs_vfs_lookup,
1243 	.symlink = v9fs_vfs_symlink,
1244 	.link = v9fs_vfs_link,
1245 	.unlink = v9fs_vfs_unlink,
1246 	.mkdir = v9fs_vfs_mkdir,
1247 	.rmdir = v9fs_vfs_rmdir,
1248 	.mknod = v9fs_vfs_mknod,
1249 	.rename = v9fs_vfs_rename,
1250 	.getattr = v9fs_vfs_getattr,
1251 	.setattr = v9fs_vfs_setattr,
1252 };
1253 
1254 static const struct inode_operations v9fs_dir_inode_operations = {
1255 	.create = v9fs_vfs_create,
1256 	.lookup = v9fs_vfs_lookup,
1257 	.unlink = v9fs_vfs_unlink,
1258 	.mkdir = v9fs_vfs_mkdir,
1259 	.rmdir = v9fs_vfs_rmdir,
1260 	.mknod = v9fs_vfs_mknod,
1261 	.rename = v9fs_vfs_rename,
1262 	.getattr = v9fs_vfs_getattr,
1263 	.setattr = v9fs_vfs_setattr,
1264 };
1265 
1266 static const struct inode_operations v9fs_file_inode_operations = {
1267 	.getattr = v9fs_vfs_getattr,
1268 	.setattr = v9fs_vfs_setattr,
1269 };
1270 
1271 static const struct inode_operations v9fs_symlink_inode_operations = {
1272 	.readlink = generic_readlink,
1273 	.follow_link = v9fs_vfs_follow_link,
1274 	.put_link = v9fs_vfs_put_link,
1275 	.getattr = v9fs_vfs_getattr,
1276 	.setattr = v9fs_vfs_setattr,
1277 };
1278 
1279