xref: /openbmc/linux/fs/9p/vfs_inode.c (revision 002dff36)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  linux/fs/9p/vfs_inode.c
4  *
5  * This file contains vfs inode ops for the 9P2000 protocol.
6  *
7  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
8  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
9  */
10 
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12 
13 #include <linux/module.h>
14 #include <linux/errno.h>
15 #include <linux/fs.h>
16 #include <linux/file.h>
17 #include <linux/pagemap.h>
18 #include <linux/stat.h>
19 #include <linux/string.h>
20 #include <linux/inet.h>
21 #include <linux/namei.h>
22 #include <linux/idr.h>
23 #include <linux/sched.h>
24 #include <linux/slab.h>
25 #include <linux/xattr.h>
26 #include <linux/posix_acl.h>
27 #include <net/9p/9p.h>
28 #include <net/9p/client.h>
29 
30 #include "v9fs.h"
31 #include "v9fs_vfs.h"
32 #include "fid.h"
33 #include "cache.h"
34 #include "xattr.h"
35 #include "acl.h"
36 
37 static const struct inode_operations v9fs_dir_inode_operations;
38 static const struct inode_operations v9fs_dir_inode_operations_dotu;
39 static const struct inode_operations v9fs_file_inode_operations;
40 static const struct inode_operations v9fs_symlink_inode_operations;
41 
42 /**
43  * unixmode2p9mode - convert unix mode bits to plan 9
44  * @v9ses: v9fs session information
45  * @mode: mode to convert
46  *
47  */
48 
49 static u32 unixmode2p9mode(struct v9fs_session_info *v9ses, umode_t mode)
50 {
51 	int res;
52 	res = mode & 0777;
53 	if (S_ISDIR(mode))
54 		res |= P9_DMDIR;
55 	if (v9fs_proto_dotu(v9ses)) {
56 		if (v9ses->nodev == 0) {
57 			if (S_ISSOCK(mode))
58 				res |= P9_DMSOCKET;
59 			if (S_ISFIFO(mode))
60 				res |= P9_DMNAMEDPIPE;
61 			if (S_ISBLK(mode))
62 				res |= P9_DMDEVICE;
63 			if (S_ISCHR(mode))
64 				res |= P9_DMDEVICE;
65 		}
66 
67 		if ((mode & S_ISUID) == S_ISUID)
68 			res |= P9_DMSETUID;
69 		if ((mode & S_ISGID) == S_ISGID)
70 			res |= P9_DMSETGID;
71 		if ((mode & S_ISVTX) == S_ISVTX)
72 			res |= P9_DMSETVTX;
73 	}
74 	return res;
75 }
76 
77 /**
78  * p9mode2perm- convert plan9 mode bits to unix permission bits
79  * @v9ses: v9fs session information
80  * @stat: p9_wstat from which mode need to be derived
81  *
82  */
83 static int p9mode2perm(struct v9fs_session_info *v9ses,
84 		       struct p9_wstat *stat)
85 {
86 	int res;
87 	int mode = stat->mode;
88 
89 	res = mode & S_IALLUGO;
90 	if (v9fs_proto_dotu(v9ses)) {
91 		if ((mode & P9_DMSETUID) == P9_DMSETUID)
92 			res |= S_ISUID;
93 
94 		if ((mode & P9_DMSETGID) == P9_DMSETGID)
95 			res |= S_ISGID;
96 
97 		if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
98 			res |= S_ISVTX;
99 	}
100 	return res;
101 }
102 
103 /**
104  * p9mode2unixmode- convert plan9 mode bits to unix mode bits
105  * @v9ses: v9fs session information
106  * @stat: p9_wstat from which mode need to be derived
107  * @rdev: major number, minor number in case of device files.
108  *
109  */
110 static umode_t p9mode2unixmode(struct v9fs_session_info *v9ses,
111 			       struct p9_wstat *stat, dev_t *rdev)
112 {
113 	int res;
114 	u32 mode = stat->mode;
115 
116 	*rdev = 0;
117 	res = p9mode2perm(v9ses, stat);
118 
119 	if ((mode & P9_DMDIR) == P9_DMDIR)
120 		res |= S_IFDIR;
121 	else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
122 		res |= S_IFLNK;
123 	else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
124 		 && (v9ses->nodev == 0))
125 		res |= S_IFSOCK;
126 	else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
127 		 && (v9ses->nodev == 0))
128 		res |= S_IFIFO;
129 	else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
130 		 && (v9ses->nodev == 0)) {
131 		char type = 0, ext[32];
132 		int major = -1, minor = -1;
133 
134 		strlcpy(ext, stat->extension, sizeof(ext));
135 		sscanf(ext, "%c %i %i", &type, &major, &minor);
136 		switch (type) {
137 		case 'c':
138 			res |= S_IFCHR;
139 			break;
140 		case 'b':
141 			res |= S_IFBLK;
142 			break;
143 		default:
144 			p9_debug(P9_DEBUG_ERROR, "Unknown special type %c %s\n",
145 				 type, stat->extension);
146 		}
147 		*rdev = MKDEV(major, minor);
148 	} else
149 		res |= S_IFREG;
150 
151 	return res;
152 }
153 
154 /**
155  * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
156  * @uflags: flags to convert
157  * @extended: if .u extensions are active
158  */
159 
160 int v9fs_uflags2omode(int uflags, int extended)
161 {
162 	int ret;
163 
164 	ret = 0;
165 	switch (uflags&3) {
166 	default:
167 	case O_RDONLY:
168 		ret = P9_OREAD;
169 		break;
170 
171 	case O_WRONLY:
172 		ret = P9_OWRITE;
173 		break;
174 
175 	case O_RDWR:
176 		ret = P9_ORDWR;
177 		break;
178 	}
179 
180 	if (extended) {
181 		if (uflags & O_EXCL)
182 			ret |= P9_OEXCL;
183 
184 		if (uflags & O_APPEND)
185 			ret |= P9_OAPPEND;
186 	}
187 
188 	return ret;
189 }
190 
191 /**
192  * v9fs_blank_wstat - helper function to setup a 9P stat structure
193  * @wstat: structure to initialize
194  *
195  */
196 
197 void
198 v9fs_blank_wstat(struct p9_wstat *wstat)
199 {
200 	wstat->type = ~0;
201 	wstat->dev = ~0;
202 	wstat->qid.type = ~0;
203 	wstat->qid.version = ~0;
204 	*((long long *)&wstat->qid.path) = ~0;
205 	wstat->mode = ~0;
206 	wstat->atime = ~0;
207 	wstat->mtime = ~0;
208 	wstat->length = ~0;
209 	wstat->name = NULL;
210 	wstat->uid = NULL;
211 	wstat->gid = NULL;
212 	wstat->muid = NULL;
213 	wstat->n_uid = INVALID_UID;
214 	wstat->n_gid = INVALID_GID;
215 	wstat->n_muid = INVALID_UID;
216 	wstat->extension = NULL;
217 }
218 
219 /**
220  * v9fs_alloc_inode - helper function to allocate an inode
221  *
222  */
223 struct inode *v9fs_alloc_inode(struct super_block *sb)
224 {
225 	struct v9fs_inode *v9inode;
226 	v9inode = (struct v9fs_inode *)kmem_cache_alloc(v9fs_inode_cache,
227 							GFP_KERNEL);
228 	if (!v9inode)
229 		return NULL;
230 #ifdef CONFIG_9P_FSCACHE
231 	v9inode->fscache = NULL;
232 	mutex_init(&v9inode->fscache_lock);
233 #endif
234 	v9inode->writeback_fid = NULL;
235 	v9inode->cache_validity = 0;
236 	mutex_init(&v9inode->v_mutex);
237 	return &v9inode->vfs_inode;
238 }
239 
240 /**
241  * v9fs_free_inode - destroy an inode
242  *
243  */
244 
245 void v9fs_free_inode(struct inode *inode)
246 {
247 	kmem_cache_free(v9fs_inode_cache, V9FS_I(inode));
248 }
249 
250 int v9fs_init_inode(struct v9fs_session_info *v9ses,
251 		    struct inode *inode, umode_t mode, dev_t rdev)
252 {
253 	int err = 0;
254 
255 	inode_init_owner(inode, NULL, mode);
256 	inode->i_blocks = 0;
257 	inode->i_rdev = rdev;
258 	inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
259 	inode->i_mapping->a_ops = &v9fs_addr_operations;
260 
261 	switch (mode & S_IFMT) {
262 	case S_IFIFO:
263 	case S_IFBLK:
264 	case S_IFCHR:
265 	case S_IFSOCK:
266 		if (v9fs_proto_dotl(v9ses)) {
267 			inode->i_op = &v9fs_file_inode_operations_dotl;
268 		} else if (v9fs_proto_dotu(v9ses)) {
269 			inode->i_op = &v9fs_file_inode_operations;
270 		} else {
271 			p9_debug(P9_DEBUG_ERROR,
272 				 "special files without extended mode\n");
273 			err = -EINVAL;
274 			goto error;
275 		}
276 		init_special_inode(inode, inode->i_mode, inode->i_rdev);
277 		break;
278 	case S_IFREG:
279 		if (v9fs_proto_dotl(v9ses)) {
280 			inode->i_op = &v9fs_file_inode_operations_dotl;
281 			if (v9ses->cache == CACHE_LOOSE ||
282 			    v9ses->cache == CACHE_FSCACHE)
283 				inode->i_fop =
284 					&v9fs_cached_file_operations_dotl;
285 			else if (v9ses->cache == CACHE_MMAP)
286 				inode->i_fop = &v9fs_mmap_file_operations_dotl;
287 			else
288 				inode->i_fop = &v9fs_file_operations_dotl;
289 		} else {
290 			inode->i_op = &v9fs_file_inode_operations;
291 			if (v9ses->cache == CACHE_LOOSE ||
292 			    v9ses->cache == CACHE_FSCACHE)
293 				inode->i_fop =
294 					&v9fs_cached_file_operations;
295 			else if (v9ses->cache == CACHE_MMAP)
296 				inode->i_fop = &v9fs_mmap_file_operations;
297 			else
298 				inode->i_fop = &v9fs_file_operations;
299 		}
300 
301 		break;
302 	case S_IFLNK:
303 		if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
304 			p9_debug(P9_DEBUG_ERROR,
305 				 "extended modes used with legacy protocol\n");
306 			err = -EINVAL;
307 			goto error;
308 		}
309 
310 		if (v9fs_proto_dotl(v9ses))
311 			inode->i_op = &v9fs_symlink_inode_operations_dotl;
312 		else
313 			inode->i_op = &v9fs_symlink_inode_operations;
314 
315 		break;
316 	case S_IFDIR:
317 		inc_nlink(inode);
318 		if (v9fs_proto_dotl(v9ses))
319 			inode->i_op = &v9fs_dir_inode_operations_dotl;
320 		else if (v9fs_proto_dotu(v9ses))
321 			inode->i_op = &v9fs_dir_inode_operations_dotu;
322 		else
323 			inode->i_op = &v9fs_dir_inode_operations;
324 
325 		if (v9fs_proto_dotl(v9ses))
326 			inode->i_fop = &v9fs_dir_operations_dotl;
327 		else
328 			inode->i_fop = &v9fs_dir_operations;
329 
330 		break;
331 	default:
332 		p9_debug(P9_DEBUG_ERROR, "BAD mode 0x%hx S_IFMT 0x%x\n",
333 			 mode, mode & S_IFMT);
334 		err = -EINVAL;
335 		goto error;
336 	}
337 error:
338 	return err;
339 
340 }
341 
342 /**
343  * v9fs_get_inode - helper function to setup an inode
344  * @sb: superblock
345  * @mode: mode to setup inode with
346  *
347  */
348 
349 struct inode *v9fs_get_inode(struct super_block *sb, umode_t mode, dev_t rdev)
350 {
351 	int err;
352 	struct inode *inode;
353 	struct v9fs_session_info *v9ses = sb->s_fs_info;
354 
355 	p9_debug(P9_DEBUG_VFS, "super block: %p mode: %ho\n", sb, mode);
356 
357 	inode = new_inode(sb);
358 	if (!inode) {
359 		pr_warn("%s (%d): Problem allocating inode\n",
360 			__func__, task_pid_nr(current));
361 		return ERR_PTR(-ENOMEM);
362 	}
363 	err = v9fs_init_inode(v9ses, inode, mode, rdev);
364 	if (err) {
365 		iput(inode);
366 		return ERR_PTR(err);
367 	}
368 	return inode;
369 }
370 
371 /*
372 static struct v9fs_fid*
373 v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
374 {
375 	int err;
376 	int nfid;
377 	struct v9fs_fid *ret;
378 	struct v9fs_fcall *fcall;
379 
380 	nfid = v9fs_get_idpool(&v9ses->fidpool);
381 	if (nfid < 0) {
382 		eprintk(KERN_WARNING, "no free fids available\n");
383 		return ERR_PTR(-ENOSPC);
384 	}
385 
386 	err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
387 		&fcall);
388 
389 	if (err < 0) {
390 		if (fcall && fcall->id == RWALK)
391 			goto clunk_fid;
392 
393 		PRINT_FCALL_ERROR("walk error", fcall);
394 		v9fs_put_idpool(nfid, &v9ses->fidpool);
395 		goto error;
396 	}
397 
398 	kfree(fcall);
399 	fcall = NULL;
400 	ret = v9fs_fid_create(v9ses, nfid);
401 	if (!ret) {
402 		err = -ENOMEM;
403 		goto clunk_fid;
404 	}
405 
406 	err = v9fs_fid_insert(ret, dentry);
407 	if (err < 0) {
408 		v9fs_fid_destroy(ret);
409 		goto clunk_fid;
410 	}
411 
412 	return ret;
413 
414 clunk_fid:
415 	v9fs_t_clunk(v9ses, nfid);
416 
417 error:
418 	kfree(fcall);
419 	return ERR_PTR(err);
420 }
421 */
422 
423 
424 /**
425  * v9fs_clear_inode - release an inode
426  * @inode: inode to release
427  *
428  */
429 void v9fs_evict_inode(struct inode *inode)
430 {
431 	struct v9fs_inode *v9inode = V9FS_I(inode);
432 
433 	truncate_inode_pages_final(&inode->i_data);
434 	clear_inode(inode);
435 	filemap_fdatawrite(&inode->i_data);
436 
437 	v9fs_cache_inode_put_cookie(inode);
438 	/* clunk the fid stashed in writeback_fid */
439 	if (v9inode->writeback_fid) {
440 		p9_client_clunk(v9inode->writeback_fid);
441 		v9inode->writeback_fid = NULL;
442 	}
443 }
444 
445 static int v9fs_test_inode(struct inode *inode, void *data)
446 {
447 	int umode;
448 	dev_t rdev;
449 	struct v9fs_inode *v9inode = V9FS_I(inode);
450 	struct p9_wstat *st = (struct p9_wstat *)data;
451 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
452 
453 	umode = p9mode2unixmode(v9ses, st, &rdev);
454 	/* don't match inode of different type */
455 	if ((inode->i_mode & S_IFMT) != (umode & S_IFMT))
456 		return 0;
457 
458 	/* compare qid details */
459 	if (memcmp(&v9inode->qid.version,
460 		   &st->qid.version, sizeof(v9inode->qid.version)))
461 		return 0;
462 
463 	if (v9inode->qid.type != st->qid.type)
464 		return 0;
465 
466 	if (v9inode->qid.path != st->qid.path)
467 		return 0;
468 	return 1;
469 }
470 
471 static int v9fs_test_new_inode(struct inode *inode, void *data)
472 {
473 	return 0;
474 }
475 
476 static int v9fs_set_inode(struct inode *inode,  void *data)
477 {
478 	struct v9fs_inode *v9inode = V9FS_I(inode);
479 	struct p9_wstat *st = (struct p9_wstat *)data;
480 
481 	memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
482 	return 0;
483 }
484 
485 static struct inode *v9fs_qid_iget(struct super_block *sb,
486 				   struct p9_qid *qid,
487 				   struct p9_wstat *st,
488 				   int new)
489 {
490 	dev_t rdev;
491 	int retval;
492 	umode_t umode;
493 	unsigned long i_ino;
494 	struct inode *inode;
495 	struct v9fs_session_info *v9ses = sb->s_fs_info;
496 	int (*test)(struct inode *, void *);
497 
498 	if (new)
499 		test = v9fs_test_new_inode;
500 	else
501 		test = v9fs_test_inode;
502 
503 	i_ino = v9fs_qid2ino(qid);
504 	inode = iget5_locked(sb, i_ino, test, v9fs_set_inode, st);
505 	if (!inode)
506 		return ERR_PTR(-ENOMEM);
507 	if (!(inode->i_state & I_NEW))
508 		return inode;
509 	/*
510 	 * initialize the inode with the stat info
511 	 * FIXME!! we may need support for stale inodes
512 	 * later.
513 	 */
514 	inode->i_ino = i_ino;
515 	umode = p9mode2unixmode(v9ses, st, &rdev);
516 	retval = v9fs_init_inode(v9ses, inode, umode, rdev);
517 	if (retval)
518 		goto error;
519 
520 	v9fs_stat2inode(st, inode, sb, 0);
521 	v9fs_cache_inode_get_cookie(inode);
522 	unlock_new_inode(inode);
523 	return inode;
524 error:
525 	iget_failed(inode);
526 	return ERR_PTR(retval);
527 
528 }
529 
530 struct inode *
531 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
532 		    struct super_block *sb, int new)
533 {
534 	struct p9_wstat *st;
535 	struct inode *inode = NULL;
536 
537 	st = p9_client_stat(fid);
538 	if (IS_ERR(st))
539 		return ERR_CAST(st);
540 
541 	inode = v9fs_qid_iget(sb, &st->qid, st, new);
542 	p9stat_free(st);
543 	kfree(st);
544 	return inode;
545 }
546 
547 /**
548  * v9fs_at_to_dotl_flags- convert Linux specific AT flags to
549  * plan 9 AT flag.
550  * @flags: flags to convert
551  */
552 static int v9fs_at_to_dotl_flags(int flags)
553 {
554 	int rflags = 0;
555 	if (flags & AT_REMOVEDIR)
556 		rflags |= P9_DOTL_AT_REMOVEDIR;
557 	return rflags;
558 }
559 
560 /**
561  * v9fs_dec_count - helper functon to drop i_nlink.
562  *
563  * If a directory had nlink <= 2 (including . and ..), then we should not drop
564  * the link count, which indicates the underlying exported fs doesn't maintain
565  * nlink accurately. e.g.
566  * - overlayfs sets nlink to 1 for merged dir
567  * - ext4 (with dir_nlink feature enabled) sets nlink to 1 if a dir has more
568  *   than EXT4_LINK_MAX (65000) links.
569  *
570  * @inode: inode whose nlink is being dropped
571  */
572 static void v9fs_dec_count(struct inode *inode)
573 {
574 	if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
575 		drop_nlink(inode);
576 }
577 
578 /**
579  * v9fs_remove - helper function to remove files and directories
580  * @dir: directory inode that is being deleted
581  * @dentry:  dentry that is being deleted
582  * @flags: removing a directory
583  *
584  */
585 
586 static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
587 {
588 	struct inode *inode;
589 	int retval = -EOPNOTSUPP;
590 	struct p9_fid *v9fid, *dfid;
591 	struct v9fs_session_info *v9ses;
592 
593 	p9_debug(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
594 		 dir, dentry, flags);
595 
596 	v9ses = v9fs_inode2v9ses(dir);
597 	inode = d_inode(dentry);
598 	dfid = v9fs_parent_fid(dentry);
599 	if (IS_ERR(dfid)) {
600 		retval = PTR_ERR(dfid);
601 		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
602 		return retval;
603 	}
604 	if (v9fs_proto_dotl(v9ses))
605 		retval = p9_client_unlinkat(dfid, dentry->d_name.name,
606 					    v9fs_at_to_dotl_flags(flags));
607 	if (retval == -EOPNOTSUPP) {
608 		/* Try the one based on path */
609 		v9fid = v9fs_fid_clone(dentry);
610 		if (IS_ERR(v9fid))
611 			return PTR_ERR(v9fid);
612 		retval = p9_client_remove(v9fid);
613 	}
614 	if (!retval) {
615 		/*
616 		 * directories on unlink should have zero
617 		 * link count
618 		 */
619 		if (flags & AT_REMOVEDIR) {
620 			clear_nlink(inode);
621 			v9fs_dec_count(dir);
622 		} else
623 			v9fs_dec_count(inode);
624 
625 		v9fs_invalidate_inode_attr(inode);
626 		v9fs_invalidate_inode_attr(dir);
627 	}
628 	return retval;
629 }
630 
631 /**
632  * v9fs_create - Create a file
633  * @v9ses: session information
634  * @dir: directory that dentry is being created in
635  * @dentry:  dentry that is being created
636  * @extension: 9p2000.u extension string to support devices, etc.
637  * @perm: create permissions
638  * @mode: open mode
639  *
640  */
641 static struct p9_fid *
642 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
643 		struct dentry *dentry, char *extension, u32 perm, u8 mode)
644 {
645 	int err;
646 	const unsigned char *name;
647 	struct p9_fid *dfid, *ofid, *fid;
648 	struct inode *inode;
649 
650 	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
651 
652 	err = 0;
653 	ofid = NULL;
654 	fid = NULL;
655 	name = dentry->d_name.name;
656 	dfid = v9fs_parent_fid(dentry);
657 	if (IS_ERR(dfid)) {
658 		err = PTR_ERR(dfid);
659 		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
660 		return ERR_PTR(err);
661 	}
662 
663 	/* clone a fid to use for creation */
664 	ofid = clone_fid(dfid);
665 	if (IS_ERR(ofid)) {
666 		err = PTR_ERR(ofid);
667 		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
668 		return ERR_PTR(err);
669 	}
670 
671 	err = p9_client_fcreate(ofid, name, perm, mode, extension);
672 	if (err < 0) {
673 		p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
674 		goto error;
675 	}
676 
677 	if (!(perm & P9_DMLINK)) {
678 		/* now walk from the parent so we can get unopened fid */
679 		fid = p9_client_walk(dfid, 1, &name, 1);
680 		if (IS_ERR(fid)) {
681 			err = PTR_ERR(fid);
682 			p9_debug(P9_DEBUG_VFS,
683 				   "p9_client_walk failed %d\n", err);
684 			fid = NULL;
685 			goto error;
686 		}
687 		/*
688 		 * instantiate inode and assign the unopened fid to the dentry
689 		 */
690 		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
691 		if (IS_ERR(inode)) {
692 			err = PTR_ERR(inode);
693 			p9_debug(P9_DEBUG_VFS,
694 				   "inode creation failed %d\n", err);
695 			goto error;
696 		}
697 		v9fs_fid_add(dentry, fid);
698 		d_instantiate(dentry, inode);
699 	}
700 	return ofid;
701 error:
702 	if (ofid)
703 		p9_client_clunk(ofid);
704 
705 	if (fid)
706 		p9_client_clunk(fid);
707 
708 	return ERR_PTR(err);
709 }
710 
711 /**
712  * v9fs_vfs_create - VFS hook to create a regular file
713  *
714  * open(.., O_CREAT) is handled in v9fs_vfs_atomic_open().  This is only called
715  * for mknod(2).
716  *
717  * @dir: directory inode that is being created
718  * @dentry:  dentry that is being deleted
719  * @mode: create permissions
720  *
721  */
722 
723 static int
724 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
725 		bool excl)
726 {
727 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
728 	u32 perm = unixmode2p9mode(v9ses, mode);
729 	struct p9_fid *fid;
730 
731 	/* P9_OEXCL? */
732 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_ORDWR);
733 	if (IS_ERR(fid))
734 		return PTR_ERR(fid);
735 
736 	v9fs_invalidate_inode_attr(dir);
737 	p9_client_clunk(fid);
738 
739 	return 0;
740 }
741 
742 /**
743  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
744  * @dir:  inode that is being unlinked
745  * @dentry: dentry that is being unlinked
746  * @mode: mode for new directory
747  *
748  */
749 
750 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
751 {
752 	int err;
753 	u32 perm;
754 	struct p9_fid *fid;
755 	struct v9fs_session_info *v9ses;
756 
757 	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
758 	err = 0;
759 	v9ses = v9fs_inode2v9ses(dir);
760 	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
761 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
762 	if (IS_ERR(fid)) {
763 		err = PTR_ERR(fid);
764 		fid = NULL;
765 	} else {
766 		inc_nlink(dir);
767 		v9fs_invalidate_inode_attr(dir);
768 	}
769 
770 	if (fid)
771 		p9_client_clunk(fid);
772 
773 	return err;
774 }
775 
776 /**
777  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
778  * @dir:  inode that is being walked from
779  * @dentry: dentry that is being walked to?
780  * @flags: lookup flags (unused)
781  *
782  */
783 
784 struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
785 				      unsigned int flags)
786 {
787 	struct dentry *res;
788 	struct v9fs_session_info *v9ses;
789 	struct p9_fid *dfid, *fid;
790 	struct inode *inode;
791 	const unsigned char *name;
792 
793 	p9_debug(P9_DEBUG_VFS, "dir: %p dentry: (%pd) %p flags: %x\n",
794 		 dir, dentry, dentry, flags);
795 
796 	if (dentry->d_name.len > NAME_MAX)
797 		return ERR_PTR(-ENAMETOOLONG);
798 
799 	v9ses = v9fs_inode2v9ses(dir);
800 	/* We can walk d_parent because we hold the dir->i_mutex */
801 	dfid = v9fs_parent_fid(dentry);
802 	if (IS_ERR(dfid))
803 		return ERR_CAST(dfid);
804 
805 	/*
806 	 * Make sure we don't use a wrong inode due to parallel
807 	 * unlink. For cached mode create calls request for new
808 	 * inode. But with cache disabled, lookup should do this.
809 	 */
810 	name = dentry->d_name.name;
811 	fid = p9_client_walk(dfid, 1, &name, 1);
812 	if (fid == ERR_PTR(-ENOENT))
813 		inode = NULL;
814 	else if (IS_ERR(fid))
815 		inode = ERR_CAST(fid);
816 	else if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
817 		inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
818 	else
819 		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
820 	/*
821 	 * If we had a rename on the server and a parallel lookup
822 	 * for the new name, then make sure we instantiate with
823 	 * the new name. ie look up for a/b, while on server somebody
824 	 * moved b under k and client parallely did a lookup for
825 	 * k/b.
826 	 */
827 	res = d_splice_alias(inode, dentry);
828 	if (!IS_ERR(fid)) {
829 		if (!res)
830 			v9fs_fid_add(dentry, fid);
831 		else if (!IS_ERR(res))
832 			v9fs_fid_add(res, fid);
833 		else
834 			p9_client_clunk(fid);
835 	}
836 	return res;
837 }
838 
839 static int
840 v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
841 		     struct file *file, unsigned flags, umode_t mode)
842 {
843 	int err;
844 	u32 perm;
845 	struct v9fs_inode *v9inode;
846 	struct v9fs_session_info *v9ses;
847 	struct p9_fid *fid, *inode_fid;
848 	struct dentry *res = NULL;
849 
850 	if (d_in_lookup(dentry)) {
851 		res = v9fs_vfs_lookup(dir, dentry, 0);
852 		if (IS_ERR(res))
853 			return PTR_ERR(res);
854 
855 		if (res)
856 			dentry = res;
857 	}
858 
859 	/* Only creates */
860 	if (!(flags & O_CREAT) || d_really_is_positive(dentry))
861 		return finish_no_open(file, res);
862 
863 	err = 0;
864 
865 	v9ses = v9fs_inode2v9ses(dir);
866 	perm = unixmode2p9mode(v9ses, mode);
867 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
868 				v9fs_uflags2omode(flags,
869 						v9fs_proto_dotu(v9ses)));
870 	if (IS_ERR(fid)) {
871 		err = PTR_ERR(fid);
872 		fid = NULL;
873 		goto error;
874 	}
875 
876 	v9fs_invalidate_inode_attr(dir);
877 	v9inode = V9FS_I(d_inode(dentry));
878 	mutex_lock(&v9inode->v_mutex);
879 	if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
880 	    !v9inode->writeback_fid &&
881 	    ((flags & O_ACCMODE) != O_RDONLY)) {
882 		/*
883 		 * clone a fid and add it to writeback_fid
884 		 * we do it during open time instead of
885 		 * page dirty time via write_begin/page_mkwrite
886 		 * because we want write after unlink usecase
887 		 * to work.
888 		 */
889 		inode_fid = v9fs_writeback_fid(dentry);
890 		if (IS_ERR(inode_fid)) {
891 			err = PTR_ERR(inode_fid);
892 			mutex_unlock(&v9inode->v_mutex);
893 			goto error;
894 		}
895 		v9inode->writeback_fid = (void *) inode_fid;
896 	}
897 	mutex_unlock(&v9inode->v_mutex);
898 	err = finish_open(file, dentry, generic_file_open);
899 	if (err)
900 		goto error;
901 
902 	file->private_data = fid;
903 	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
904 		v9fs_cache_inode_set_cookie(d_inode(dentry), file);
905 
906 	file->f_mode |= FMODE_CREATED;
907 out:
908 	dput(res);
909 	return err;
910 
911 error:
912 	if (fid)
913 		p9_client_clunk(fid);
914 	goto out;
915 }
916 
917 /**
918  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
919  * @i:  inode that is being unlinked
920  * @d: dentry that is being unlinked
921  *
922  */
923 
924 int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
925 {
926 	return v9fs_remove(i, d, 0);
927 }
928 
929 /**
930  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
931  * @i:  inode that is being unlinked
932  * @d: dentry that is being unlinked
933  *
934  */
935 
936 int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
937 {
938 	return v9fs_remove(i, d, AT_REMOVEDIR);
939 }
940 
941 /**
942  * v9fs_vfs_rename - VFS hook to rename an inode
943  * @old_dir:  old dir inode
944  * @old_dentry: old dentry
945  * @new_dir: new dir inode
946  * @new_dentry: new dentry
947  *
948  */
949 
950 int
951 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
952 		struct inode *new_dir, struct dentry *new_dentry,
953 		unsigned int flags)
954 {
955 	int retval;
956 	struct inode *old_inode;
957 	struct inode *new_inode;
958 	struct v9fs_session_info *v9ses;
959 	struct p9_fid *oldfid;
960 	struct p9_fid *olddirfid;
961 	struct p9_fid *newdirfid;
962 	struct p9_wstat wstat;
963 
964 	if (flags)
965 		return -EINVAL;
966 
967 	p9_debug(P9_DEBUG_VFS, "\n");
968 	retval = 0;
969 	old_inode = d_inode(old_dentry);
970 	new_inode = d_inode(new_dentry);
971 	v9ses = v9fs_inode2v9ses(old_inode);
972 	oldfid = v9fs_fid_lookup(old_dentry);
973 	if (IS_ERR(oldfid))
974 		return PTR_ERR(oldfid);
975 
976 	olddirfid = clone_fid(v9fs_parent_fid(old_dentry));
977 	if (IS_ERR(olddirfid)) {
978 		retval = PTR_ERR(olddirfid);
979 		goto done;
980 	}
981 
982 	newdirfid = clone_fid(v9fs_parent_fid(new_dentry));
983 	if (IS_ERR(newdirfid)) {
984 		retval = PTR_ERR(newdirfid);
985 		goto clunk_olddir;
986 	}
987 
988 	down_write(&v9ses->rename_sem);
989 	if (v9fs_proto_dotl(v9ses)) {
990 		retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
991 					    newdirfid, new_dentry->d_name.name);
992 		if (retval == -EOPNOTSUPP)
993 			retval = p9_client_rename(oldfid, newdirfid,
994 						  new_dentry->d_name.name);
995 		if (retval != -EOPNOTSUPP)
996 			goto clunk_newdir;
997 	}
998 	if (old_dentry->d_parent != new_dentry->d_parent) {
999 		/*
1000 		 * 9P .u can only handle file rename in the same directory
1001 		 */
1002 
1003 		p9_debug(P9_DEBUG_ERROR, "old dir and new dir are different\n");
1004 		retval = -EXDEV;
1005 		goto clunk_newdir;
1006 	}
1007 	v9fs_blank_wstat(&wstat);
1008 	wstat.muid = v9ses->uname;
1009 	wstat.name = new_dentry->d_name.name;
1010 	retval = p9_client_wstat(oldfid, &wstat);
1011 
1012 clunk_newdir:
1013 	if (!retval) {
1014 		if (new_inode) {
1015 			if (S_ISDIR(new_inode->i_mode))
1016 				clear_nlink(new_inode);
1017 			else
1018 				v9fs_dec_count(new_inode);
1019 		}
1020 		if (S_ISDIR(old_inode->i_mode)) {
1021 			if (!new_inode)
1022 				inc_nlink(new_dir);
1023 			v9fs_dec_count(old_dir);
1024 		}
1025 		v9fs_invalidate_inode_attr(old_inode);
1026 		v9fs_invalidate_inode_attr(old_dir);
1027 		v9fs_invalidate_inode_attr(new_dir);
1028 
1029 		/* successful rename */
1030 		d_move(old_dentry, new_dentry);
1031 	}
1032 	up_write(&v9ses->rename_sem);
1033 	p9_client_clunk(newdirfid);
1034 
1035 clunk_olddir:
1036 	p9_client_clunk(olddirfid);
1037 
1038 done:
1039 	return retval;
1040 }
1041 
1042 /**
1043  * v9fs_vfs_getattr - retrieve file metadata
1044  * @path: Object to query
1045  * @stat: metadata structure to populate
1046  * @request_mask: Mask of STATX_xxx flags indicating the caller's interests
1047  * @flags: AT_STATX_xxx setting
1048  *
1049  */
1050 
1051 static int
1052 v9fs_vfs_getattr(const struct path *path, struct kstat *stat,
1053 		 u32 request_mask, unsigned int flags)
1054 {
1055 	struct dentry *dentry = path->dentry;
1056 	struct v9fs_session_info *v9ses;
1057 	struct p9_fid *fid;
1058 	struct p9_wstat *st;
1059 
1060 	p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
1061 	v9ses = v9fs_dentry2v9ses(dentry);
1062 	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
1063 		generic_fillattr(d_inode(dentry), stat);
1064 		return 0;
1065 	}
1066 	fid = v9fs_fid_lookup(dentry);
1067 	if (IS_ERR(fid))
1068 		return PTR_ERR(fid);
1069 
1070 	st = p9_client_stat(fid);
1071 	if (IS_ERR(st))
1072 		return PTR_ERR(st);
1073 
1074 	v9fs_stat2inode(st, d_inode(dentry), dentry->d_sb, 0);
1075 	generic_fillattr(d_inode(dentry), stat);
1076 
1077 	p9stat_free(st);
1078 	kfree(st);
1079 	return 0;
1080 }
1081 
1082 /**
1083  * v9fs_vfs_setattr - set file metadata
1084  * @dentry: file whose metadata to set
1085  * @iattr: metadata assignment structure
1086  *
1087  */
1088 
1089 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
1090 {
1091 	int retval;
1092 	struct v9fs_session_info *v9ses;
1093 	struct p9_fid *fid;
1094 	struct p9_wstat wstat;
1095 
1096 	p9_debug(P9_DEBUG_VFS, "\n");
1097 	retval = setattr_prepare(dentry, iattr);
1098 	if (retval)
1099 		return retval;
1100 
1101 	retval = -EPERM;
1102 	v9ses = v9fs_dentry2v9ses(dentry);
1103 	fid = v9fs_fid_lookup(dentry);
1104 	if(IS_ERR(fid))
1105 		return PTR_ERR(fid);
1106 
1107 	v9fs_blank_wstat(&wstat);
1108 	if (iattr->ia_valid & ATTR_MODE)
1109 		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
1110 
1111 	if (iattr->ia_valid & ATTR_MTIME)
1112 		wstat.mtime = iattr->ia_mtime.tv_sec;
1113 
1114 	if (iattr->ia_valid & ATTR_ATIME)
1115 		wstat.atime = iattr->ia_atime.tv_sec;
1116 
1117 	if (iattr->ia_valid & ATTR_SIZE)
1118 		wstat.length = iattr->ia_size;
1119 
1120 	if (v9fs_proto_dotu(v9ses)) {
1121 		if (iattr->ia_valid & ATTR_UID)
1122 			wstat.n_uid = iattr->ia_uid;
1123 
1124 		if (iattr->ia_valid & ATTR_GID)
1125 			wstat.n_gid = iattr->ia_gid;
1126 	}
1127 
1128 	/* Write all dirty data */
1129 	if (d_is_reg(dentry))
1130 		filemap_write_and_wait(d_inode(dentry)->i_mapping);
1131 
1132 	retval = p9_client_wstat(fid, &wstat);
1133 	if (retval < 0)
1134 		return retval;
1135 
1136 	if ((iattr->ia_valid & ATTR_SIZE) &&
1137 	    iattr->ia_size != i_size_read(d_inode(dentry)))
1138 		truncate_setsize(d_inode(dentry), iattr->ia_size);
1139 
1140 	v9fs_invalidate_inode_attr(d_inode(dentry));
1141 
1142 	setattr_copy(d_inode(dentry), iattr);
1143 	mark_inode_dirty(d_inode(dentry));
1144 	return 0;
1145 }
1146 
1147 /**
1148  * v9fs_stat2inode - populate an inode structure with mistat info
1149  * @stat: Plan 9 metadata (mistat) structure
1150  * @inode: inode to populate
1151  * @sb: superblock of filesystem
1152  * @flags: control flags (e.g. V9FS_STAT2INODE_KEEP_ISIZE)
1153  *
1154  */
1155 
1156 void
1157 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
1158 		 struct super_block *sb, unsigned int flags)
1159 {
1160 	umode_t mode;
1161 	char ext[32];
1162 	char tag_name[14];
1163 	unsigned int i_nlink;
1164 	struct v9fs_session_info *v9ses = sb->s_fs_info;
1165 	struct v9fs_inode *v9inode = V9FS_I(inode);
1166 
1167 	set_nlink(inode, 1);
1168 
1169 	inode->i_atime.tv_sec = stat->atime;
1170 	inode->i_mtime.tv_sec = stat->mtime;
1171 	inode->i_ctime.tv_sec = stat->mtime;
1172 
1173 	inode->i_uid = v9ses->dfltuid;
1174 	inode->i_gid = v9ses->dfltgid;
1175 
1176 	if (v9fs_proto_dotu(v9ses)) {
1177 		inode->i_uid = stat->n_uid;
1178 		inode->i_gid = stat->n_gid;
1179 	}
1180 	if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
1181 		if (v9fs_proto_dotu(v9ses) && (stat->extension[0] != '\0')) {
1182 			/*
1183 			 * Hadlink support got added later to
1184 			 * to the .u extension. So there can be
1185 			 * server out there that doesn't support
1186 			 * this even with .u extension. So check
1187 			 * for non NULL stat->extension
1188 			 */
1189 			strlcpy(ext, stat->extension, sizeof(ext));
1190 			/* HARDLINKCOUNT %u */
1191 			sscanf(ext, "%13s %u", tag_name, &i_nlink);
1192 			if (!strncmp(tag_name, "HARDLINKCOUNT", 13))
1193 				set_nlink(inode, i_nlink);
1194 		}
1195 	}
1196 	mode = p9mode2perm(v9ses, stat);
1197 	mode |= inode->i_mode & ~S_IALLUGO;
1198 	inode->i_mode = mode;
1199 
1200 	if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
1201 		v9fs_i_size_write(inode, stat->length);
1202 	/* not real number of blocks, but 512 byte ones ... */
1203 	inode->i_blocks = (stat->length + 512 - 1) >> 9;
1204 	v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
1205 }
1206 
1207 /**
1208  * v9fs_qid2ino - convert qid into inode number
1209  * @qid: qid to hash
1210  *
1211  * BUG: potential for inode number collisions?
1212  */
1213 
1214 ino_t v9fs_qid2ino(struct p9_qid *qid)
1215 {
1216 	u64 path = qid->path + 2;
1217 	ino_t i = 0;
1218 
1219 	if (sizeof(ino_t) == sizeof(path))
1220 		memcpy(&i, &path, sizeof(ino_t));
1221 	else
1222 		i = (ino_t) (path ^ (path >> 32));
1223 
1224 	return i;
1225 }
1226 
1227 /**
1228  * v9fs_vfs_get_link - follow a symlink path
1229  * @dentry: dentry for symlink
1230  * @inode: inode for symlink
1231  * @done: delayed call for when we are done with the return value
1232  */
1233 
1234 static const char *v9fs_vfs_get_link(struct dentry *dentry,
1235 				     struct inode *inode,
1236 				     struct delayed_call *done)
1237 {
1238 	struct v9fs_session_info *v9ses;
1239 	struct p9_fid *fid;
1240 	struct p9_wstat *st;
1241 	char *res;
1242 
1243 	if (!dentry)
1244 		return ERR_PTR(-ECHILD);
1245 
1246 	v9ses = v9fs_dentry2v9ses(dentry);
1247 	fid = v9fs_fid_lookup(dentry);
1248 	p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
1249 
1250 	if (IS_ERR(fid))
1251 		return ERR_CAST(fid);
1252 
1253 	if (!v9fs_proto_dotu(v9ses))
1254 		return ERR_PTR(-EBADF);
1255 
1256 	st = p9_client_stat(fid);
1257 	if (IS_ERR(st))
1258 		return ERR_CAST(st);
1259 
1260 	if (!(st->mode & P9_DMSYMLINK)) {
1261 		p9stat_free(st);
1262 		kfree(st);
1263 		return ERR_PTR(-EINVAL);
1264 	}
1265 	res = st->extension;
1266 	st->extension = NULL;
1267 	if (strlen(res) >= PATH_MAX)
1268 		res[PATH_MAX - 1] = '\0';
1269 
1270 	p9stat_free(st);
1271 	kfree(st);
1272 	set_delayed_call(done, kfree_link, res);
1273 	return res;
1274 }
1275 
1276 /**
1277  * v9fs_vfs_mkspecial - create a special file
1278  * @dir: inode to create special file in
1279  * @dentry: dentry to create
1280  * @perm: mode to create special file
1281  * @extension: 9p2000.u format extension string representing special file
1282  *
1283  */
1284 
1285 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1286 	u32 perm, const char *extension)
1287 {
1288 	struct p9_fid *fid;
1289 	struct v9fs_session_info *v9ses;
1290 
1291 	v9ses = v9fs_inode2v9ses(dir);
1292 	if (!v9fs_proto_dotu(v9ses)) {
1293 		p9_debug(P9_DEBUG_ERROR, "not extended\n");
1294 		return -EPERM;
1295 	}
1296 
1297 	fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1298 								P9_OREAD);
1299 	if (IS_ERR(fid))
1300 		return PTR_ERR(fid);
1301 
1302 	v9fs_invalidate_inode_attr(dir);
1303 	p9_client_clunk(fid);
1304 	return 0;
1305 }
1306 
1307 /**
1308  * v9fs_vfs_symlink - helper function to create symlinks
1309  * @dir: directory inode containing symlink
1310  * @dentry: dentry for symlink
1311  * @symname: symlink data
1312  *
1313  * See Also: 9P2000.u RFC for more information
1314  *
1315  */
1316 
1317 static int
1318 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1319 {
1320 	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%s\n",
1321 		 dir->i_ino, dentry, symname);
1322 
1323 	return v9fs_vfs_mkspecial(dir, dentry, P9_DMSYMLINK, symname);
1324 }
1325 
1326 #define U32_MAX_DIGITS 10
1327 
1328 /**
1329  * v9fs_vfs_link - create a hardlink
1330  * @old_dentry: dentry for file to link to
1331  * @dir: inode destination for new link
1332  * @dentry: dentry for link
1333  *
1334  */
1335 
1336 static int
1337 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1338 	      struct dentry *dentry)
1339 {
1340 	int retval;
1341 	char name[1 + U32_MAX_DIGITS + 2]; /* sign + number + \n + \0 */
1342 	struct p9_fid *oldfid;
1343 
1344 	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%pd\n",
1345 		 dir->i_ino, dentry, old_dentry);
1346 
1347 	oldfid = v9fs_fid_clone(old_dentry);
1348 	if (IS_ERR(oldfid))
1349 		return PTR_ERR(oldfid);
1350 
1351 	sprintf(name, "%d\n", oldfid->fid);
1352 	retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1353 	if (!retval) {
1354 		v9fs_refresh_inode(oldfid, d_inode(old_dentry));
1355 		v9fs_invalidate_inode_attr(dir);
1356 	}
1357 	p9_client_clunk(oldfid);
1358 	return retval;
1359 }
1360 
1361 /**
1362  * v9fs_vfs_mknod - create a special file
1363  * @dir: inode destination for new link
1364  * @dentry: dentry for file
1365  * @mode: mode for creation
1366  * @rdev: device associated with special file
1367  *
1368  */
1369 
1370 static int
1371 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
1372 {
1373 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
1374 	int retval;
1375 	char name[2 + U32_MAX_DIGITS + 1 + U32_MAX_DIGITS + 1];
1376 	u32 perm;
1377 
1378 	p9_debug(P9_DEBUG_VFS, " %lu,%pd mode: %hx MAJOR: %u MINOR: %u\n",
1379 		 dir->i_ino, dentry, mode,
1380 		 MAJOR(rdev), MINOR(rdev));
1381 
1382 	/* build extension */
1383 	if (S_ISBLK(mode))
1384 		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1385 	else if (S_ISCHR(mode))
1386 		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1387 	else
1388 		*name = 0;
1389 
1390 	perm = unixmode2p9mode(v9ses, mode);
1391 	retval = v9fs_vfs_mkspecial(dir, dentry, perm, name);
1392 
1393 	return retval;
1394 }
1395 
1396 int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
1397 {
1398 	int umode;
1399 	dev_t rdev;
1400 	struct p9_wstat *st;
1401 	struct v9fs_session_info *v9ses;
1402 	unsigned int flags;
1403 
1404 	v9ses = v9fs_inode2v9ses(inode);
1405 	st = p9_client_stat(fid);
1406 	if (IS_ERR(st))
1407 		return PTR_ERR(st);
1408 	/*
1409 	 * Don't update inode if the file type is different
1410 	 */
1411 	umode = p9mode2unixmode(v9ses, st, &rdev);
1412 	if ((inode->i_mode & S_IFMT) != (umode & S_IFMT))
1413 		goto out;
1414 
1415 	/*
1416 	 * We don't want to refresh inode->i_size,
1417 	 * because we may have cached data
1418 	 */
1419 	flags = (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) ?
1420 		V9FS_STAT2INODE_KEEP_ISIZE : 0;
1421 	v9fs_stat2inode(st, inode, inode->i_sb, flags);
1422 out:
1423 	p9stat_free(st);
1424 	kfree(st);
1425 	return 0;
1426 }
1427 
1428 static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1429 	.create = v9fs_vfs_create,
1430 	.lookup = v9fs_vfs_lookup,
1431 	.atomic_open = v9fs_vfs_atomic_open,
1432 	.symlink = v9fs_vfs_symlink,
1433 	.link = v9fs_vfs_link,
1434 	.unlink = v9fs_vfs_unlink,
1435 	.mkdir = v9fs_vfs_mkdir,
1436 	.rmdir = v9fs_vfs_rmdir,
1437 	.mknod = v9fs_vfs_mknod,
1438 	.rename = v9fs_vfs_rename,
1439 	.getattr = v9fs_vfs_getattr,
1440 	.setattr = v9fs_vfs_setattr,
1441 };
1442 
1443 static const struct inode_operations v9fs_dir_inode_operations = {
1444 	.create = v9fs_vfs_create,
1445 	.lookup = v9fs_vfs_lookup,
1446 	.atomic_open = v9fs_vfs_atomic_open,
1447 	.unlink = v9fs_vfs_unlink,
1448 	.mkdir = v9fs_vfs_mkdir,
1449 	.rmdir = v9fs_vfs_rmdir,
1450 	.mknod = v9fs_vfs_mknod,
1451 	.rename = v9fs_vfs_rename,
1452 	.getattr = v9fs_vfs_getattr,
1453 	.setattr = v9fs_vfs_setattr,
1454 };
1455 
1456 static const struct inode_operations v9fs_file_inode_operations = {
1457 	.getattr = v9fs_vfs_getattr,
1458 	.setattr = v9fs_vfs_setattr,
1459 };
1460 
1461 static const struct inode_operations v9fs_symlink_inode_operations = {
1462 	.get_link = v9fs_vfs_get_link,
1463 	.getattr = v9fs_vfs_getattr,
1464 	.setattr = v9fs_vfs_setattr,
1465 };
1466 
1467