xref: /linux/fs/9p/vfs_inode.c (revision 1bc18858358d7a4e263a63b59a12cbfd25c16670)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * This file contains vfs inode ops for the 9P2000 protocol.
4  *
5  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
6  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
7  */
8 
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 
11 #include <linux/module.h>
12 #include <linux/errno.h>
13 #include <linux/fs.h>
14 #include <linux/file.h>
15 #include <linux/pagemap.h>
16 #include <linux/stat.h>
17 #include <linux/string.h>
18 #include <linux/namei.h>
19 #include <linux/sched.h>
20 #include <linux/slab.h>
21 #include <linux/xattr.h>
22 #include <linux/posix_acl.h>
23 #include <net/9p/9p.h>
24 #include <net/9p/client.h>
25 
26 #include "v9fs.h"
27 #include "v9fs_vfs.h"
28 #include "fid.h"
29 #include "cache.h"
30 #include "xattr.h"
31 #include "acl.h"
32 
33 static const struct inode_operations v9fs_dir_inode_operations;
34 static const struct inode_operations v9fs_dir_inode_operations_dotu;
35 static const struct inode_operations v9fs_file_inode_operations;
36 static const struct inode_operations v9fs_symlink_inode_operations;
37 
38 /**
39  * unixmode2p9mode - convert unix mode bits to plan 9
40  * @v9ses: v9fs session information
41  * @mode: mode to convert
42  *
43  */
44 
45 static u32 unixmode2p9mode(struct v9fs_session_info *v9ses, umode_t mode)
46 {
47 	int res;
48 
49 	res = mode & 0777;
50 	if (S_ISDIR(mode))
51 		res |= P9_DMDIR;
52 	if (v9fs_proto_dotu(v9ses)) {
53 		if (v9ses->nodev == 0) {
54 			if (S_ISSOCK(mode))
55 				res |= P9_DMSOCKET;
56 			if (S_ISFIFO(mode))
57 				res |= P9_DMNAMEDPIPE;
58 			if (S_ISBLK(mode))
59 				res |= P9_DMDEVICE;
60 			if (S_ISCHR(mode))
61 				res |= P9_DMDEVICE;
62 		}
63 
64 		if ((mode & S_ISUID) == S_ISUID)
65 			res |= P9_DMSETUID;
66 		if ((mode & S_ISGID) == S_ISGID)
67 			res |= P9_DMSETGID;
68 		if ((mode & S_ISVTX) == S_ISVTX)
69 			res |= P9_DMSETVTX;
70 	}
71 	return res;
72 }
73 
74 /**
75  * p9mode2perm- convert plan9 mode bits to unix permission bits
76  * @v9ses: v9fs session information
77  * @stat: p9_wstat from which mode need to be derived
78  *
79  */
80 static int p9mode2perm(struct v9fs_session_info *v9ses,
81 		       struct p9_wstat *stat)
82 {
83 	int res;
84 	int mode = stat->mode;
85 
86 	res = mode & 0777; /* S_IRWXUGO */
87 	if (v9fs_proto_dotu(v9ses)) {
88 		if ((mode & P9_DMSETUID) == P9_DMSETUID)
89 			res |= S_ISUID;
90 
91 		if ((mode & P9_DMSETGID) == P9_DMSETGID)
92 			res |= S_ISGID;
93 
94 		if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
95 			res |= S_ISVTX;
96 	}
97 	return res;
98 }
99 
100 /**
101  * p9mode2unixmode- convert plan9 mode bits to unix mode bits
102  * @v9ses: v9fs session information
103  * @stat: p9_wstat from which mode need to be derived
104  * @rdev: major number, minor number in case of device files.
105  *
106  */
107 static umode_t p9mode2unixmode(struct v9fs_session_info *v9ses,
108 			       struct p9_wstat *stat, dev_t *rdev)
109 {
110 	int res, r;
111 	u32 mode = stat->mode;
112 
113 	*rdev = 0;
114 	res = p9mode2perm(v9ses, stat);
115 
116 	if ((mode & P9_DMDIR) == P9_DMDIR)
117 		res |= S_IFDIR;
118 	else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
119 		res |= S_IFLNK;
120 	else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
121 		 && (v9ses->nodev == 0))
122 		res |= S_IFSOCK;
123 	else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
124 		 && (v9ses->nodev == 0))
125 		res |= S_IFIFO;
126 	else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
127 		 && (v9ses->nodev == 0)) {
128 		char type = 0;
129 		int major = -1, minor = -1;
130 
131 		r = sscanf(stat->extension, "%c %i %i", &type, &major, &minor);
132 		if (r != 3) {
133 			p9_debug(P9_DEBUG_ERROR,
134 				 "invalid device string, umode will be bogus: %s\n",
135 				 stat->extension);
136 			return res;
137 		}
138 		switch (type) {
139 		case 'c':
140 			res |= S_IFCHR;
141 			break;
142 		case 'b':
143 			res |= S_IFBLK;
144 			break;
145 		default:
146 			p9_debug(P9_DEBUG_ERROR, "Unknown special type %c %s\n",
147 				 type, stat->extension);
148 		}
149 		*rdev = MKDEV(major, minor);
150 	} else
151 		res |= S_IFREG;
152 
153 	return res;
154 }
155 
156 /**
157  * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
158  * @uflags: flags to convert
159  * @extended: if .u extensions are active
160  */
161 
162 int v9fs_uflags2omode(int uflags, int extended)
163 {
164 	int ret;
165 
166 	switch (uflags&3) {
167 	default:
168 	case O_RDONLY:
169 		ret = P9_OREAD;
170 		break;
171 
172 	case O_WRONLY:
173 		ret = P9_OWRITE;
174 		break;
175 
176 	case O_RDWR:
177 		ret = P9_ORDWR;
178 		break;
179 	}
180 
181 	if (uflags & O_TRUNC)
182 		ret |= P9_OTRUNC;
183 
184 	if (extended) {
185 		if (uflags & O_EXCL)
186 			ret |= P9_OEXCL;
187 
188 		if (uflags & O_APPEND)
189 			ret |= P9_OAPPEND;
190 	}
191 
192 	return ret;
193 }
194 
195 /**
196  * v9fs_blank_wstat - helper function to setup a 9P stat structure
197  * @wstat: structure to initialize
198  *
199  */
200 
201 void
202 v9fs_blank_wstat(struct p9_wstat *wstat)
203 {
204 	wstat->type = ~0;
205 	wstat->dev = ~0;
206 	wstat->qid.type = ~0;
207 	wstat->qid.version = ~0;
208 	*((long long *)&wstat->qid.path) = ~0;
209 	wstat->mode = ~0;
210 	wstat->atime = ~0;
211 	wstat->mtime = ~0;
212 	wstat->length = ~0;
213 	wstat->name = NULL;
214 	wstat->uid = NULL;
215 	wstat->gid = NULL;
216 	wstat->muid = NULL;
217 	wstat->n_uid = INVALID_UID;
218 	wstat->n_gid = INVALID_GID;
219 	wstat->n_muid = INVALID_UID;
220 	wstat->extension = NULL;
221 }
222 
223 /**
224  * v9fs_alloc_inode - helper function to allocate an inode
225  * @sb: The superblock to allocate the inode from
226  */
227 struct inode *v9fs_alloc_inode(struct super_block *sb)
228 {
229 	struct v9fs_inode *v9inode;
230 
231 	v9inode = alloc_inode_sb(sb, v9fs_inode_cache, GFP_KERNEL);
232 	if (!v9inode)
233 		return NULL;
234 	v9inode->cache_validity = 0;
235 	mutex_init(&v9inode->v_mutex);
236 	return &v9inode->netfs.inode;
237 }
238 
239 /**
240  * v9fs_free_inode - destroy an inode
241  * @inode: The inode to be freed
242  */
243 
244 void v9fs_free_inode(struct inode *inode)
245 {
246 	kmem_cache_free(v9fs_inode_cache, V9FS_I(inode));
247 }
248 
249 /*
250  * Set parameters for the netfs library
251  */
252 void v9fs_set_netfs_context(struct inode *inode)
253 {
254 	struct v9fs_inode *v9inode = V9FS_I(inode);
255 	netfs_inode_init(&v9inode->netfs, &v9fs_req_ops, true);
256 }
257 
258 int v9fs_init_inode(struct v9fs_session_info *v9ses,
259 		    struct inode *inode, umode_t mode, dev_t rdev)
260 {
261 	int err = 0;
262 
263 	inode_init_owner(&nop_mnt_idmap, inode, NULL, mode);
264 	inode->i_blocks = 0;
265 	inode->i_rdev = rdev;
266 	simple_inode_init_ts(inode);
267 	inode->i_mapping->a_ops = &v9fs_addr_operations;
268 	inode->i_private = NULL;
269 
270 	switch (mode & S_IFMT) {
271 	case S_IFIFO:
272 	case S_IFBLK:
273 	case S_IFCHR:
274 	case S_IFSOCK:
275 		if (v9fs_proto_dotl(v9ses)) {
276 			inode->i_op = &v9fs_file_inode_operations_dotl;
277 		} else if (v9fs_proto_dotu(v9ses)) {
278 			inode->i_op = &v9fs_file_inode_operations;
279 		} else {
280 			p9_debug(P9_DEBUG_ERROR,
281 				 "special files without extended mode\n");
282 			err = -EINVAL;
283 			goto error;
284 		}
285 		init_special_inode(inode, inode->i_mode, inode->i_rdev);
286 		break;
287 	case S_IFREG:
288 		if (v9fs_proto_dotl(v9ses)) {
289 			inode->i_op = &v9fs_file_inode_operations_dotl;
290 			inode->i_fop = &v9fs_file_operations_dotl;
291 		} else {
292 			inode->i_op = &v9fs_file_inode_operations;
293 			inode->i_fop = &v9fs_file_operations;
294 		}
295 
296 		break;
297 	case S_IFLNK:
298 		if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
299 			p9_debug(P9_DEBUG_ERROR,
300 				 "extended modes used with legacy protocol\n");
301 			err = -EINVAL;
302 			goto error;
303 		}
304 
305 		if (v9fs_proto_dotl(v9ses)) {
306 			inode->i_op = &v9fs_symlink_inode_operations_dotl;
307 			inode_nohighmem(inode);
308 		} else {
309 			inode->i_op = &v9fs_symlink_inode_operations;
310 		}
311 
312 		break;
313 	case S_IFDIR:
314 		inc_nlink(inode);
315 		if (v9fs_proto_dotl(v9ses))
316 			inode->i_op = &v9fs_dir_inode_operations_dotl;
317 		else if (v9fs_proto_dotu(v9ses))
318 			inode->i_op = &v9fs_dir_inode_operations_dotu;
319 		else
320 			inode->i_op = &v9fs_dir_inode_operations;
321 
322 		if (v9fs_proto_dotl(v9ses))
323 			inode->i_fop = &v9fs_dir_operations_dotl;
324 		else
325 			inode->i_fop = &v9fs_dir_operations;
326 
327 		break;
328 	default:
329 		p9_debug(P9_DEBUG_ERROR, "BAD mode 0x%hx S_IFMT 0x%x\n",
330 			 mode, mode & S_IFMT);
331 		err = -EINVAL;
332 		goto error;
333 	}
334 error:
335 	return err;
336 
337 }
338 
339 /**
340  * v9fs_evict_inode - Remove an inode from the inode cache
341  * @inode: inode to release
342  *
343  */
344 void v9fs_evict_inode(struct inode *inode)
345 {
346 	struct v9fs_inode __maybe_unused *v9inode = V9FS_I(inode);
347 	__le32 __maybe_unused version;
348 
349 	if (!is_bad_inode(inode)) {
350 		netfs_wait_for_outstanding_io(inode);
351 		truncate_inode_pages_final(&inode->i_data);
352 
353 		version = cpu_to_le32(v9inode->qid.version);
354 		netfs_clear_inode_writeback(inode, &version);
355 
356 		clear_inode(inode);
357 		filemap_fdatawrite(&inode->i_data);
358 
359 #ifdef CONFIG_9P_FSCACHE
360 		if (v9fs_inode_cookie(v9inode))
361 			fscache_relinquish_cookie(v9fs_inode_cookie(v9inode), false);
362 #endif
363 	} else
364 		clear_inode(inode);
365 }
366 
367 static int v9fs_test_inode(struct inode *inode, void *data)
368 {
369 	int umode;
370 	dev_t rdev;
371 	struct v9fs_inode *v9inode = V9FS_I(inode);
372 	struct p9_wstat *st = (struct p9_wstat *)data;
373 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
374 
375 	umode = p9mode2unixmode(v9ses, st, &rdev);
376 	/* don't match inode of different type */
377 	if (inode_wrong_type(inode, umode))
378 		return 0;
379 
380 	/* compare qid details */
381 	if (memcmp(&v9inode->qid.version,
382 		   &st->qid.version, sizeof(v9inode->qid.version)))
383 		return 0;
384 
385 	if (v9inode->qid.type != st->qid.type)
386 		return 0;
387 
388 	if (v9inode->qid.path != st->qid.path)
389 		return 0;
390 	return 1;
391 }
392 
393 static int v9fs_test_new_inode(struct inode *inode, void *data)
394 {
395 	return 0;
396 }
397 
398 static int v9fs_set_inode(struct inode *inode,  void *data)
399 {
400 	struct v9fs_inode *v9inode = V9FS_I(inode);
401 	struct p9_wstat *st = (struct p9_wstat *)data;
402 
403 	memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
404 	return 0;
405 }
406 
407 static struct inode *v9fs_qid_iget(struct super_block *sb,
408 				   struct p9_qid *qid,
409 				   struct p9_wstat *st,
410 				   int new)
411 {
412 	dev_t rdev;
413 	int retval;
414 	umode_t umode;
415 	struct inode *inode;
416 	struct v9fs_session_info *v9ses = sb->s_fs_info;
417 	int (*test)(struct inode *inode, void *data);
418 
419 	if (new)
420 		test = v9fs_test_new_inode;
421 	else
422 		test = v9fs_test_inode;
423 
424 	inode = iget5_locked(sb, QID2INO(qid), test, v9fs_set_inode, st);
425 	if (!inode)
426 		return ERR_PTR(-ENOMEM);
427 	if (!(inode_state_read_once(inode) & I_NEW))
428 		return inode;
429 	/*
430 	 * initialize the inode with the stat info
431 	 * FIXME!! we may need support for stale inodes
432 	 * later.
433 	 */
434 	inode->i_ino = QID2INO(qid);
435 	umode = p9mode2unixmode(v9ses, st, &rdev);
436 	retval = v9fs_init_inode(v9ses, inode, umode, rdev);
437 	if (retval)
438 		goto error;
439 
440 	v9fs_stat2inode(st, inode, sb, 0);
441 	v9fs_set_netfs_context(inode);
442 	v9fs_cache_inode_get_cookie(inode);
443 	unlock_new_inode(inode);
444 	return inode;
445 error:
446 	iget_failed(inode);
447 	return ERR_PTR(retval);
448 
449 }
450 
451 struct inode *
452 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
453 		    struct super_block *sb, int new)
454 {
455 	struct p9_wstat *st;
456 	struct inode *inode = NULL;
457 
458 	st = p9_client_stat(fid);
459 	if (IS_ERR(st))
460 		return ERR_CAST(st);
461 
462 	inode = v9fs_qid_iget(sb, &st->qid, st, new);
463 	p9stat_free(st);
464 	kfree(st);
465 	return inode;
466 }
467 
468 /**
469  * v9fs_at_to_dotl_flags- convert Linux specific AT flags to
470  * plan 9 AT flag.
471  * @flags: flags to convert
472  */
473 static int v9fs_at_to_dotl_flags(int flags)
474 {
475 	int rflags = 0;
476 
477 	if (flags & AT_REMOVEDIR)
478 		rflags |= P9_DOTL_AT_REMOVEDIR;
479 
480 	return rflags;
481 }
482 
483 /**
484  * v9fs_dec_count - helper functon to drop i_nlink.
485  *
486  * If a directory had nlink <= 2 (including . and ..), then we should not drop
487  * the link count, which indicates the underlying exported fs doesn't maintain
488  * nlink accurately. e.g.
489  * - overlayfs sets nlink to 1 for merged dir
490  * - ext4 (with dir_nlink feature enabled) sets nlink to 1 if a dir has more
491  *   than EXT4_LINK_MAX (65000) links.
492  *
493  * In cacheless mode the server is the source of truth for nlink and the
494  * inode is going away immediately, so locally adjusting i_nlink buys
495  * nothing and races with concurrent metadata fetches that may already
496  * have observed the post-unlink value (nlink == 0).
497  *
498  * @inode: inode whose nlink is being dropped
499  */
500 static void v9fs_dec_count(struct inode *inode)
501 {
502 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
503 
504 	if (!(v9ses->cache & (CACHE_META | CACHE_LOOSE)))
505 		return;
506 	if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
507 		drop_nlink(inode);
508 }
509 
510 /**
511  * v9fs_remove - helper function to remove files and directories
512  * @dir: directory inode that is being deleted
513  * @dentry:  dentry that is being deleted
514  * @flags: removing a directory
515  *
516  */
517 
518 static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
519 {
520 	struct inode *inode;
521 	int retval = -EOPNOTSUPP;
522 	struct p9_fid *v9fid, *dfid;
523 	struct v9fs_session_info *v9ses;
524 
525 	p9_debug(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
526 		 dir, dentry, flags);
527 
528 	v9ses = v9fs_inode2v9ses(dir);
529 	inode = d_inode(dentry);
530 	dfid = v9fs_parent_fid(dentry);
531 	if (IS_ERR(dfid)) {
532 		retval = PTR_ERR(dfid);
533 		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
534 		return retval;
535 	}
536 	if (v9fs_proto_dotl(v9ses))
537 		retval = p9_client_unlinkat(dfid, dentry->d_name.name,
538 					    v9fs_at_to_dotl_flags(flags));
539 	p9_fid_put(dfid);
540 	if (retval == -EOPNOTSUPP) {
541 		/* Try the one based on path */
542 		v9fid = v9fs_fid_clone(dentry);
543 		if (IS_ERR(v9fid))
544 			return PTR_ERR(v9fid);
545 		retval = p9_client_remove(v9fid);
546 	}
547 	if (!retval) {
548 		/*
549 		 * directories on unlink should have zero
550 		 * link count
551 		 */
552 		if (flags & AT_REMOVEDIR) {
553 			clear_nlink(inode);
554 			v9fs_dec_count(dir);
555 		} else
556 			v9fs_dec_count(inode);
557 
558 		v9fs_invalidate_inode_attr(inode);
559 		v9fs_invalidate_inode_attr(dir);
560 
561 		/* invalidate all fids associated with dentry */
562 		/* NOTE: This will not include open fids */
563 		v9fs_dentry_fid_remove(dentry);
564 	}
565 	return retval;
566 }
567 
568 /**
569  * v9fs_create - Create a file
570  * @v9ses: session information
571  * @dir: directory that dentry is being created in
572  * @dentry:  dentry that is being created
573  * @extension: 9p2000.u extension string to support devices, etc.
574  * @perm: create permissions
575  * @mode: open mode
576  *
577  */
578 static struct p9_fid *
579 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
580 		struct dentry *dentry, char *extension, u32 perm, u8 mode)
581 {
582 	int err;
583 	const unsigned char *name;
584 	struct p9_fid *dfid, *ofid = NULL, *fid = NULL;
585 	struct inode *inode;
586 
587 	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
588 
589 	name = dentry->d_name.name;
590 	dfid = v9fs_parent_fid(dentry);
591 	if (IS_ERR(dfid)) {
592 		err = PTR_ERR(dfid);
593 		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
594 		return ERR_PTR(err);
595 	}
596 
597 	/* clone a fid to use for creation */
598 	ofid = clone_fid(dfid);
599 	if (IS_ERR(ofid)) {
600 		err = PTR_ERR(ofid);
601 		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
602 		goto error;
603 	}
604 
605 	err = p9_client_fcreate(ofid, name, perm, mode, extension);
606 	if (err < 0) {
607 		p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
608 		goto error;
609 	}
610 
611 	if (!(perm & P9_DMLINK)) {
612 		/* now walk from the parent so we can get unopened fid */
613 		fid = p9_client_walk(dfid, 1, &name, 1);
614 		if (IS_ERR(fid)) {
615 			err = PTR_ERR(fid);
616 			p9_debug(P9_DEBUG_VFS,
617 				   "p9_client_walk failed %d\n", err);
618 			goto error;
619 		}
620 		/*
621 		 * instantiate inode and assign the unopened fid to the dentry
622 		 */
623 		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
624 		if (IS_ERR(inode)) {
625 			err = PTR_ERR(inode);
626 			p9_debug(P9_DEBUG_VFS,
627 				   "inode creation failed %d\n", err);
628 			goto error;
629 		}
630 		v9fs_fid_add(dentry, &fid);
631 		d_instantiate(dentry, inode);
632 	}
633 	p9_fid_put(dfid);
634 	return ofid;
635 error:
636 	p9_fid_put(dfid);
637 	p9_fid_put(ofid);
638 	p9_fid_put(fid);
639 	return ERR_PTR(err);
640 }
641 
642 /**
643  * v9fs_vfs_create - VFS hook to create a regular file
644  * @idmap: idmap of the mount
645  * @dir: The parent directory
646  * @dentry: The name of file to be created
647  * @mode: The UNIX file mode to set
648  * @excl: True if the file must not yet exist
649  *
650  * open(.., O_CREAT) is handled in v9fs_vfs_atomic_open().  This is only called
651  * for mknod(2).
652  *
653  */
654 
655 static int
656 v9fs_vfs_create(struct mnt_idmap *idmap, struct inode *dir,
657 		struct dentry *dentry, umode_t mode, bool excl)
658 {
659 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
660 	u32 perm = unixmode2p9mode(v9ses, mode);
661 	struct p9_fid *fid;
662 
663 	/* P9_OEXCL? */
664 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_ORDWR);
665 	if (IS_ERR(fid))
666 		return PTR_ERR(fid);
667 
668 	v9fs_invalidate_inode_attr(dir);
669 	p9_fid_put(fid);
670 
671 	return 0;
672 }
673 
674 /**
675  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
676  * @idmap: idmap of the mount
677  * @dir:  inode that is being unlinked
678  * @dentry: dentry that is being unlinked
679  * @mode: mode for new directory
680  *
681  */
682 
683 static struct dentry *v9fs_vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
684 				     struct dentry *dentry, umode_t mode)
685 {
686 	u32 perm;
687 	struct p9_fid *fid;
688 	struct v9fs_session_info *v9ses;
689 
690 	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
691 	v9ses = v9fs_inode2v9ses(dir);
692 	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
693 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
694 	if (IS_ERR(fid))
695 		return ERR_CAST(fid);
696 	inc_nlink(dir);
697 	v9fs_invalidate_inode_attr(dir);
698 	p9_fid_put(fid);
699 	return NULL;
700 }
701 
702 /**
703  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
704  * @dir:  inode that is being walked from
705  * @dentry: dentry that is being walked to?
706  * @flags: lookup flags (unused)
707  *
708  */
709 
710 struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
711 				      unsigned int flags)
712 {
713 	struct dentry *res;
714 	struct v9fs_session_info *v9ses;
715 	struct p9_fid *dfid, *fid;
716 	struct inode *inode;
717 	const unsigned char *name;
718 
719 	p9_debug(P9_DEBUG_VFS, "dir: %p dentry: (%pd) %p flags: %x\n",
720 		 dir, dentry, dentry, flags);
721 
722 	if (dentry->d_name.len > NAME_MAX)
723 		return ERR_PTR(-ENAMETOOLONG);
724 
725 	v9ses = v9fs_inode2v9ses(dir);
726 	/* We can walk d_parent because we hold the dir->i_mutex */
727 	dfid = v9fs_parent_fid(dentry);
728 	if (IS_ERR(dfid))
729 		return ERR_CAST(dfid);
730 
731 	/*
732 	 * Make sure we don't use a wrong inode due to parallel
733 	 * unlink. For cached mode create calls request for new
734 	 * inode. But with cache disabled, lookup should do this.
735 	 */
736 	name = dentry->d_name.name;
737 	fid = p9_client_walk(dfid, 1, &name, 1);
738 	p9_fid_put(dfid);
739 	if (fid == ERR_PTR(-ENOENT)) {
740 		inode = NULL;
741 		v9fs_ndentry_refresh_timeout(dentry);
742 	} else if (IS_ERR(fid)) {
743 		inode = ERR_CAST(fid);
744 	} else if (v9ses->cache & (CACHE_META|CACHE_LOOSE)) {
745 		inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
746 	} else {
747 		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
748 	}
749 	/*
750 	 * If we had a rename on the server and a parallel lookup
751 	 * for the new name, then make sure we instantiate with
752 	 * the new name. ie look up for a/b, while on server somebody
753 	 * moved b under k and client parallely did a lookup for
754 	 * k/b.
755 	 */
756 	res = d_splice_alias(inode, dentry);
757 	if (!IS_ERR(fid)) {
758 		if (!res)
759 			v9fs_fid_add(dentry, &fid);
760 		else if (!IS_ERR(res))
761 			v9fs_fid_add(res, &fid);
762 		else
763 			p9_fid_put(fid);
764 	}
765 	return res;
766 }
767 
768 static int
769 v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
770 		     struct file *file, unsigned int flags, umode_t mode)
771 {
772 	int err;
773 	u32 perm;
774 	struct v9fs_inode __maybe_unused *v9inode;
775 	struct v9fs_session_info *v9ses;
776 	struct p9_fid *fid;
777 	struct inode *inode;
778 	int p9_omode;
779 
780 	if (d_in_lookup(dentry)) {
781 		struct dentry *res = v9fs_vfs_lookup(dir, dentry, 0);
782 		if (res || d_really_is_positive(dentry))
783 			return finish_no_open(file, res);
784 	}
785 
786 	/* Only creates */
787 	if (!(flags & O_CREAT))
788 		return finish_no_open(file, NULL);
789 
790 	v9ses = v9fs_inode2v9ses(dir);
791 	perm = unixmode2p9mode(v9ses, mode);
792 	p9_omode = v9fs_uflags2omode(flags, v9fs_proto_dotu(v9ses));
793 
794 	if ((v9ses->cache & CACHE_WRITEBACK) && (p9_omode & P9_OWRITE)) {
795 		p9_omode = (p9_omode & ~(P9_OWRITE | P9_OAPPEND)) | P9_ORDWR;
796 		p9_debug(P9_DEBUG_CACHE,
797 			"write-only file with writeback enabled, creating w/ O_RDWR\n");
798 	}
799 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, p9_omode);
800 	if (IS_ERR(fid))
801 		return PTR_ERR(fid);
802 
803 	v9fs_invalidate_inode_attr(dir);
804 	inode = d_inode(dentry);
805 	v9inode = V9FS_I(inode);
806 	err = finish_open(file, dentry, generic_file_open);
807 	if (unlikely(err)) {
808 		p9_fid_put(fid);
809 		return err;
810 	}
811 
812 	file->private_data = fid;
813 #ifdef CONFIG_9P_FSCACHE
814 	if (v9ses->cache & CACHE_FSCACHE)
815 		fscache_use_cookie(v9fs_inode_cookie(v9inode),
816 				   file->f_mode & FMODE_WRITE);
817 #endif
818 
819 	v9fs_fid_add_modes(fid, v9ses->flags, v9ses->cache, file->f_flags);
820 	v9fs_open_fid_add(inode, &fid);
821 
822 	file->f_mode |= FMODE_CREATED;
823 	return 0;
824 }
825 
826 /**
827  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
828  * @i:  inode that is being unlinked
829  * @d: dentry that is being unlinked
830  *
831  */
832 
833 int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
834 {
835 	return v9fs_remove(i, d, 0);
836 }
837 
838 /**
839  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
840  * @i:  inode that is being unlinked
841  * @d: dentry that is being unlinked
842  *
843  */
844 
845 int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
846 {
847 	return v9fs_remove(i, d, AT_REMOVEDIR);
848 }
849 
850 /**
851  * v9fs_vfs_rename - VFS hook to rename an inode
852  * @idmap: The idmap of the mount
853  * @old_dir:  old dir inode
854  * @old_dentry: old dentry
855  * @new_dir: new dir inode
856  * @new_dentry: new dentry
857  * @flags: RENAME_* flags
858  *
859  */
860 
861 int
862 v9fs_vfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
863 		struct dentry *old_dentry, struct inode *new_dir,
864 		struct dentry *new_dentry, unsigned int flags)
865 {
866 	int retval;
867 	struct inode *old_inode;
868 	struct inode *new_inode;
869 	struct v9fs_session_info *v9ses;
870 	struct p9_fid *oldfid = NULL, *dfid = NULL;
871 	struct p9_fid *olddirfid = NULL;
872 	struct p9_fid *newdirfid = NULL;
873 	struct p9_wstat wstat;
874 
875 	if (flags)
876 		return -EINVAL;
877 
878 	p9_debug(P9_DEBUG_VFS, "\n");
879 	old_inode = d_inode(old_dentry);
880 	new_inode = d_inode(new_dentry);
881 	v9ses = v9fs_inode2v9ses(old_inode);
882 	oldfid = v9fs_fid_lookup(old_dentry);
883 	if (IS_ERR(oldfid))
884 		return PTR_ERR(oldfid);
885 
886 	dfid = v9fs_parent_fid(old_dentry);
887 	olddirfid = clone_fid(dfid);
888 	p9_fid_put(dfid);
889 	dfid = NULL;
890 
891 	if (IS_ERR(olddirfid)) {
892 		retval = PTR_ERR(olddirfid);
893 		goto error;
894 	}
895 
896 	dfid = v9fs_parent_fid(new_dentry);
897 	newdirfid = clone_fid(dfid);
898 	p9_fid_put(dfid);
899 	dfid = NULL;
900 
901 	if (IS_ERR(newdirfid)) {
902 		retval = PTR_ERR(newdirfid);
903 		goto error;
904 	}
905 
906 	down_write(&v9ses->rename_sem);
907 	if (v9fs_proto_dotl(v9ses)) {
908 		retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
909 					    newdirfid, new_dentry->d_name.name);
910 		if (retval == -EOPNOTSUPP)
911 			retval = p9_client_rename(oldfid, newdirfid,
912 						  new_dentry->d_name.name);
913 		if (retval != -EOPNOTSUPP)
914 			goto error_locked;
915 	}
916 	if (old_dentry->d_parent != new_dentry->d_parent) {
917 		/*
918 		 * 9P .u can only handle file rename in the same directory
919 		 */
920 
921 		p9_debug(P9_DEBUG_ERROR, "old dir and new dir are different\n");
922 		retval = -EXDEV;
923 		goto error_locked;
924 	}
925 	v9fs_blank_wstat(&wstat);
926 	wstat.muid = v9ses->uname;
927 	wstat.name = new_dentry->d_name.name;
928 	retval = p9_client_wstat(oldfid, &wstat);
929 
930 error_locked:
931 	if (!retval) {
932 		if (new_inode) {
933 			if (S_ISDIR(new_inode->i_mode))
934 				clear_nlink(new_inode);
935 			else
936 				v9fs_dec_count(new_inode);
937 		}
938 		if (S_ISDIR(old_inode->i_mode)) {
939 			if (!new_inode)
940 				inc_nlink(new_dir);
941 			v9fs_dec_count(old_dir);
942 		}
943 		v9fs_invalidate_inode_attr(old_inode);
944 		v9fs_invalidate_inode_attr(old_dir);
945 		v9fs_invalidate_inode_attr(new_dir);
946 
947 		/* successful rename */
948 		d_move(old_dentry, new_dentry);
949 	}
950 	up_write(&v9ses->rename_sem);
951 
952 error:
953 	p9_fid_put(newdirfid);
954 	p9_fid_put(olddirfid);
955 	p9_fid_put(oldfid);
956 	return retval;
957 }
958 
959 /**
960  * v9fs_vfs_getattr - retrieve file metadata
961  * @idmap: idmap of the mount
962  * @path: Object to query
963  * @stat: metadata structure to populate
964  * @request_mask: Mask of STATX_xxx flags indicating the caller's interests
965  * @flags: AT_STATX_xxx setting
966  *
967  */
968 
969 static int
970 v9fs_vfs_getattr(struct mnt_idmap *idmap, const struct path *path,
971 		 struct kstat *stat, u32 request_mask, unsigned int flags)
972 {
973 	struct dentry *dentry = path->dentry;
974 	struct inode *inode = d_inode(dentry);
975 	struct v9fs_session_info *v9ses;
976 	struct p9_fid *fid;
977 	struct p9_wstat *st;
978 
979 	p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
980 	v9ses = v9fs_dentry2v9ses(dentry);
981 	if (v9ses->cache & (CACHE_META|CACHE_LOOSE)) {
982 		generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
983 		return 0;
984 	} else if (v9ses->cache & CACHE_WRITEBACK) {
985 		if (S_ISREG(inode->i_mode)) {
986 			int retval = filemap_fdatawrite(inode->i_mapping);
987 
988 			if (retval)
989 				p9_debug(P9_DEBUG_ERROR,
990 				    "flushing writeback during getattr returned %d\n", retval);
991 		}
992 	}
993 	fid = v9fs_fid_lookup(dentry);
994 	if (IS_ERR(fid))
995 		return PTR_ERR(fid);
996 
997 	st = p9_client_stat(fid);
998 	p9_fid_put(fid);
999 	if (IS_ERR(st))
1000 		return PTR_ERR(st);
1001 
1002 	v9fs_stat2inode(st, d_inode(dentry), dentry->d_sb, 0);
1003 	generic_fillattr(&nop_mnt_idmap, request_mask, d_inode(dentry), stat);
1004 
1005 	p9stat_free(st);
1006 	kfree(st);
1007 	return 0;
1008 }
1009 
1010 /**
1011  * v9fs_vfs_setattr - set file metadata
1012  * @idmap: idmap of the mount
1013  * @dentry: file whose metadata to set
1014  * @iattr: metadata assignment structure
1015  *
1016  */
1017 
1018 static int v9fs_vfs_setattr(struct mnt_idmap *idmap,
1019 			    struct dentry *dentry, struct iattr *iattr)
1020 {
1021 	int retval, use_dentry = 0;
1022 	struct inode *inode = d_inode(dentry);
1023 	struct v9fs_session_info *v9ses;
1024 	struct p9_fid *fid = NULL;
1025 	struct p9_wstat wstat;
1026 
1027 	p9_debug(P9_DEBUG_VFS, "\n");
1028 	retval = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
1029 	if (retval)
1030 		return retval;
1031 
1032 	v9ses = v9fs_dentry2v9ses(dentry);
1033 	if (iattr->ia_valid & ATTR_FILE) {
1034 		fid = iattr->ia_file->private_data;
1035 		WARN_ON(!fid);
1036 	}
1037 	if (!fid) {
1038 		fid = v9fs_fid_lookup(dentry);
1039 		use_dentry = 1;
1040 	}
1041 	if (IS_ERR(fid))
1042 		return PTR_ERR(fid);
1043 
1044 	v9fs_blank_wstat(&wstat);
1045 	if (iattr->ia_valid & ATTR_MODE)
1046 		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
1047 
1048 	if (iattr->ia_valid & ATTR_MTIME)
1049 		wstat.mtime = iattr->ia_mtime.tv_sec;
1050 
1051 	if (iattr->ia_valid & ATTR_ATIME)
1052 		wstat.atime = iattr->ia_atime.tv_sec;
1053 
1054 	if (iattr->ia_valid & ATTR_SIZE)
1055 		wstat.length = iattr->ia_size;
1056 
1057 	if (v9fs_proto_dotu(v9ses)) {
1058 		if (iattr->ia_valid & ATTR_UID)
1059 			wstat.n_uid = iattr->ia_uid;
1060 
1061 		if (iattr->ia_valid & ATTR_GID)
1062 			wstat.n_gid = iattr->ia_gid;
1063 	}
1064 
1065 	/* Write all dirty data */
1066 	if (d_is_reg(dentry)) {
1067 		retval = filemap_fdatawrite(inode->i_mapping);
1068 		if (retval)
1069 			p9_debug(P9_DEBUG_ERROR,
1070 			    "flushing writeback during setattr returned %d\n", retval);
1071 	}
1072 
1073 	retval = p9_client_wstat(fid, &wstat);
1074 
1075 	if (use_dentry)
1076 		p9_fid_put(fid);
1077 
1078 	if (retval < 0)
1079 		return retval;
1080 
1081 	if ((iattr->ia_valid & ATTR_SIZE) &&
1082 		 iattr->ia_size != i_size_read(inode)) {
1083 		truncate_setsize(inode, iattr->ia_size);
1084 		netfs_resize_file(netfs_inode(inode), iattr->ia_size, true);
1085 
1086 #ifdef CONFIG_9P_FSCACHE
1087 		if (v9ses->cache & CACHE_FSCACHE) {
1088 			struct v9fs_inode *v9inode = V9FS_I(inode);
1089 
1090 			fscache_resize_cookie(v9fs_inode_cookie(v9inode), iattr->ia_size);
1091 		}
1092 #endif
1093 	}
1094 
1095 	v9fs_invalidate_inode_attr(inode);
1096 
1097 	setattr_copy(&nop_mnt_idmap, inode, iattr);
1098 	mark_inode_dirty(inode);
1099 	return 0;
1100 }
1101 
1102 /**
1103  * v9fs_stat2inode - populate an inode structure with mistat info
1104  * @stat: Plan 9 metadata (mistat) structure
1105  * @inode: inode to populate
1106  * @sb: superblock of filesystem
1107  * @flags: control flags (e.g. V9FS_STAT2INODE_KEEP_ISIZE)
1108  *
1109  */
1110 
1111 void
1112 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
1113 		 struct super_block *sb, unsigned int flags)
1114 {
1115 	umode_t mode;
1116 	struct v9fs_session_info *v9ses = sb->s_fs_info;
1117 	struct v9fs_inode *v9inode = V9FS_I(inode);
1118 
1119 	inode_set_atime(inode, stat->atime, 0);
1120 	inode_set_mtime(inode, stat->mtime, 0);
1121 	inode_set_ctime(inode, stat->mtime, 0);
1122 
1123 	inode->i_uid = v9ses->dfltuid;
1124 	inode->i_gid = v9ses->dfltgid;
1125 
1126 	if (v9fs_proto_dotu(v9ses)) {
1127 		inode->i_uid = stat->n_uid;
1128 		inode->i_gid = stat->n_gid;
1129 	}
1130 	if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
1131 		if (v9fs_proto_dotu(v9ses)) {
1132 			unsigned int i_nlink;
1133 			/*
1134 			 * Hadlink support got added later to the .u extension.
1135 			 * So there can be a server out there that doesn't
1136 			 * support this even with .u extension. That would
1137 			 * just leave us with stat->extension being an empty
1138 			 * string, though.
1139 			 */
1140 			/* HARDLINKCOUNT %u */
1141 			if (sscanf(stat->extension,
1142 				   " HARDLINKCOUNT %u", &i_nlink) == 1)
1143 				set_nlink(inode, i_nlink);
1144 		}
1145 	}
1146 	mode = p9mode2perm(v9ses, stat);
1147 	mode |= inode->i_mode & ~S_IALLUGO;
1148 	inode->i_mode = mode;
1149 
1150 	spin_lock(&inode->i_lock);
1151 	netfs_write_remote_i_size(inode, stat->length);
1152 	if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
1153 		i_size_write(inode, stat->length);
1154 	/* not real number of blocks, but 512 byte ones ... */
1155 	inode->i_blocks = (stat->length + 512 - 1) >> 9;
1156 	spin_unlock(&inode->i_lock);
1157 	v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
1158 }
1159 
1160 /**
1161  * v9fs_vfs_get_link - follow a symlink path
1162  * @dentry: dentry for symlink
1163  * @inode: inode for symlink
1164  * @done: delayed call for when we are done with the return value
1165  */
1166 
1167 static const char *v9fs_vfs_get_link(struct dentry *dentry,
1168 				     struct inode *inode,
1169 				     struct delayed_call *done)
1170 {
1171 	struct v9fs_session_info *v9ses;
1172 	struct p9_fid *fid;
1173 	struct p9_wstat *st;
1174 	char *res;
1175 
1176 	if (!dentry)
1177 		return ERR_PTR(-ECHILD);
1178 
1179 	v9ses = v9fs_dentry2v9ses(dentry);
1180 	if (!v9fs_proto_dotu(v9ses))
1181 		return ERR_PTR(-EBADF);
1182 
1183 	p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
1184 	fid = v9fs_fid_lookup(dentry);
1185 
1186 	if (IS_ERR(fid))
1187 		return ERR_CAST(fid);
1188 
1189 	st = p9_client_stat(fid);
1190 	p9_fid_put(fid);
1191 	if (IS_ERR(st))
1192 		return ERR_CAST(st);
1193 
1194 	if (!(st->mode & P9_DMSYMLINK)) {
1195 		p9stat_free(st);
1196 		kfree(st);
1197 		return ERR_PTR(-EINVAL);
1198 	}
1199 	res = st->extension;
1200 	st->extension = NULL;
1201 	if (strlen(res) >= PATH_MAX)
1202 		res[PATH_MAX - 1] = '\0';
1203 
1204 	p9stat_free(st);
1205 	kfree(st);
1206 	set_delayed_call(done, kfree_link, res);
1207 	return res;
1208 }
1209 
1210 /**
1211  * v9fs_vfs_mkspecial - create a special file
1212  * @dir: inode to create special file in
1213  * @dentry: dentry to create
1214  * @perm: mode to create special file
1215  * @extension: 9p2000.u format extension string representing special file
1216  *
1217  */
1218 
1219 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1220 	u32 perm, const char *extension)
1221 {
1222 	struct p9_fid *fid;
1223 	struct v9fs_session_info *v9ses;
1224 
1225 	v9ses = v9fs_inode2v9ses(dir);
1226 	if (!v9fs_proto_dotu(v9ses)) {
1227 		p9_debug(P9_DEBUG_ERROR, "not extended\n");
1228 		return -EPERM;
1229 	}
1230 
1231 	fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1232 								P9_OREAD);
1233 	if (IS_ERR(fid))
1234 		return PTR_ERR(fid);
1235 
1236 	v9fs_invalidate_inode_attr(dir);
1237 	p9_fid_put(fid);
1238 	return 0;
1239 }
1240 
1241 /**
1242  * v9fs_vfs_symlink - helper function to create symlinks
1243  * @idmap: idmap of the mount
1244  * @dir: directory inode containing symlink
1245  * @dentry: dentry for symlink
1246  * @symname: symlink data
1247  *
1248  * See Also: 9P2000.u RFC for more information
1249  *
1250  */
1251 
1252 static int
1253 v9fs_vfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
1254 		 struct dentry *dentry, const char *symname)
1255 {
1256 	p9_debug(P9_DEBUG_VFS, " %llu,%pd,%s\n",
1257 		 dir->i_ino, dentry, symname);
1258 
1259 	return v9fs_vfs_mkspecial(dir, dentry, P9_DMSYMLINK, symname);
1260 }
1261 
1262 #define U32_MAX_DIGITS 10
1263 
1264 /**
1265  * v9fs_vfs_link - create a hardlink
1266  * @old_dentry: dentry for file to link to
1267  * @dir: inode destination for new link
1268  * @dentry: dentry for link
1269  *
1270  */
1271 
1272 static int
1273 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1274 	      struct dentry *dentry)
1275 {
1276 	int retval;
1277 	char name[1 + U32_MAX_DIGITS + 2]; /* sign + number + \n + \0 */
1278 	struct p9_fid *oldfid;
1279 
1280 	p9_debug(P9_DEBUG_VFS, " %llu,%pd,%pd\n",
1281 		 dir->i_ino, dentry, old_dentry);
1282 
1283 	oldfid = v9fs_fid_clone(old_dentry);
1284 	if (IS_ERR(oldfid))
1285 		return PTR_ERR(oldfid);
1286 
1287 	sprintf(name, "%d\n", oldfid->fid);
1288 	retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1289 	if (!retval) {
1290 		v9fs_refresh_inode(oldfid, d_inode(old_dentry));
1291 		v9fs_invalidate_inode_attr(dir);
1292 	}
1293 	p9_fid_put(oldfid);
1294 	return retval;
1295 }
1296 
1297 /**
1298  * v9fs_vfs_mknod - create a special file
1299  * @idmap: idmap of the mount
1300  * @dir: inode destination for new link
1301  * @dentry: dentry for file
1302  * @mode: mode for creation
1303  * @rdev: device associated with special file
1304  *
1305  */
1306 
1307 static int
1308 v9fs_vfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
1309 	       struct dentry *dentry, umode_t mode, dev_t rdev)
1310 {
1311 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
1312 	int retval;
1313 	char name[2 + U32_MAX_DIGITS + 1 + U32_MAX_DIGITS + 1];
1314 	u32 perm;
1315 
1316 	p9_debug(P9_DEBUG_VFS, " %llu,%pd mode: %x MAJOR: %u MINOR: %u\n",
1317 		 dir->i_ino, dentry, mode,
1318 		 MAJOR(rdev), MINOR(rdev));
1319 
1320 	/* build extension */
1321 	if (S_ISBLK(mode))
1322 		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1323 	else if (S_ISCHR(mode))
1324 		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1325 	else
1326 		*name = 0;
1327 
1328 	perm = unixmode2p9mode(v9ses, mode);
1329 	retval = v9fs_vfs_mkspecial(dir, dentry, perm, name);
1330 
1331 	return retval;
1332 }
1333 
1334 int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
1335 {
1336 	int umode;
1337 	dev_t rdev;
1338 	struct p9_wstat *st;
1339 	struct v9fs_session_info *v9ses;
1340 	unsigned int flags;
1341 
1342 	v9ses = v9fs_inode2v9ses(inode);
1343 	st = p9_client_stat(fid);
1344 	if (IS_ERR(st))
1345 		return PTR_ERR(st);
1346 	/*
1347 	 * Don't update inode if the file type is different
1348 	 */
1349 	umode = p9mode2unixmode(v9ses, st, &rdev);
1350 	if (inode_wrong_type(inode, umode))
1351 		goto out;
1352 
1353 	/*
1354 	 * We don't want to refresh inode->i_size,
1355 	 * because we may have cached data
1356 	 */
1357 	flags = (v9ses->cache & CACHE_LOOSE) ?
1358 		V9FS_STAT2INODE_KEEP_ISIZE : 0;
1359 	v9fs_stat2inode(st, inode, inode->i_sb, flags);
1360 out:
1361 	p9stat_free(st);
1362 	kfree(st);
1363 	return 0;
1364 }
1365 
1366 static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1367 	.create = v9fs_vfs_create,
1368 	.lookup = v9fs_vfs_lookup,
1369 	.atomic_open = v9fs_vfs_atomic_open,
1370 	.symlink = v9fs_vfs_symlink,
1371 	.link = v9fs_vfs_link,
1372 	.unlink = v9fs_vfs_unlink,
1373 	.mkdir = v9fs_vfs_mkdir,
1374 	.rmdir = v9fs_vfs_rmdir,
1375 	.mknod = v9fs_vfs_mknod,
1376 	.rename = v9fs_vfs_rename,
1377 	.getattr = v9fs_vfs_getattr,
1378 	.setattr = v9fs_vfs_setattr,
1379 };
1380 
1381 static const struct inode_operations v9fs_dir_inode_operations = {
1382 	.create = v9fs_vfs_create,
1383 	.lookup = v9fs_vfs_lookup,
1384 	.atomic_open = v9fs_vfs_atomic_open,
1385 	.unlink = v9fs_vfs_unlink,
1386 	.mkdir = v9fs_vfs_mkdir,
1387 	.rmdir = v9fs_vfs_rmdir,
1388 	.mknod = v9fs_vfs_mknod,
1389 	.rename = v9fs_vfs_rename,
1390 	.getattr = v9fs_vfs_getattr,
1391 	.setattr = v9fs_vfs_setattr,
1392 };
1393 
1394 static const struct inode_operations v9fs_file_inode_operations = {
1395 	.getattr = v9fs_vfs_getattr,
1396 	.setattr = v9fs_vfs_setattr,
1397 };
1398 
1399 static const struct inode_operations v9fs_symlink_inode_operations = {
1400 	.get_link = v9fs_vfs_get_link,
1401 	.getattr = v9fs_vfs_getattr,
1402 	.setattr = v9fs_vfs_setattr,
1403 };
1404