xref: /openbmc/linux/fs/9p/vfs_inode.c (revision 49c23519)
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);
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 	inode->i_atime = inode->i_mtime = inode_set_ctime_current(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 		else
308 			inode->i_op = &v9fs_symlink_inode_operations;
309 
310 		break;
311 	case S_IFDIR:
312 		inc_nlink(inode);
313 		if (v9fs_proto_dotl(v9ses))
314 			inode->i_op = &v9fs_dir_inode_operations_dotl;
315 		else if (v9fs_proto_dotu(v9ses))
316 			inode->i_op = &v9fs_dir_inode_operations_dotu;
317 		else
318 			inode->i_op = &v9fs_dir_inode_operations;
319 
320 		if (v9fs_proto_dotl(v9ses))
321 			inode->i_fop = &v9fs_dir_operations_dotl;
322 		else
323 			inode->i_fop = &v9fs_dir_operations;
324 
325 		break;
326 	default:
327 		p9_debug(P9_DEBUG_ERROR, "BAD mode 0x%hx S_IFMT 0x%x\n",
328 			 mode, mode & S_IFMT);
329 		err = -EINVAL;
330 		goto error;
331 	}
332 error:
333 	return err;
334 
335 }
336 
337 /**
338  * v9fs_get_inode - helper function to setup an inode
339  * @sb: superblock
340  * @mode: mode to setup inode with
341  * @rdev: The device numbers to set
342  */
343 
344 struct inode *v9fs_get_inode(struct super_block *sb, umode_t mode, dev_t rdev)
345 {
346 	int err;
347 	struct inode *inode;
348 	struct v9fs_session_info *v9ses = sb->s_fs_info;
349 
350 	p9_debug(P9_DEBUG_VFS, "super block: %p mode: %ho\n", sb, mode);
351 
352 	inode = new_inode(sb);
353 	if (!inode) {
354 		pr_warn("%s (%d): Problem allocating inode\n",
355 			__func__, task_pid_nr(current));
356 		return ERR_PTR(-ENOMEM);
357 	}
358 	err = v9fs_init_inode(v9ses, inode, mode, rdev);
359 	if (err) {
360 		iput(inode);
361 		return ERR_PTR(err);
362 	}
363 	v9fs_set_netfs_context(inode);
364 	return inode;
365 }
366 
367 /**
368  * v9fs_evict_inode - Remove an inode from the inode cache
369  * @inode: inode to release
370  *
371  */
372 void v9fs_evict_inode(struct inode *inode)
373 {
374 	struct v9fs_inode __maybe_unused *v9inode = V9FS_I(inode);
375 	__le32 __maybe_unused version;
376 
377 	truncate_inode_pages_final(&inode->i_data);
378 
379 #ifdef CONFIG_9P_FSCACHE
380 	version = cpu_to_le32(v9inode->qid.version);
381 	fscache_clear_inode_writeback(v9fs_inode_cookie(v9inode), inode,
382 				      &version);
383 #endif
384 
385 	clear_inode(inode);
386 	filemap_fdatawrite(&inode->i_data);
387 
388 #ifdef CONFIG_9P_FSCACHE
389 	fscache_relinquish_cookie(v9fs_inode_cookie(v9inode), false);
390 #endif
391 }
392 
393 static int v9fs_test_inode(struct inode *inode, void *data)
394 {
395 	int umode;
396 	dev_t rdev;
397 	struct v9fs_inode *v9inode = V9FS_I(inode);
398 	struct p9_wstat *st = (struct p9_wstat *)data;
399 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
400 
401 	umode = p9mode2unixmode(v9ses, st, &rdev);
402 	/* don't match inode of different type */
403 	if (inode_wrong_type(inode, umode))
404 		return 0;
405 
406 	/* compare qid details */
407 	if (memcmp(&v9inode->qid.version,
408 		   &st->qid.version, sizeof(v9inode->qid.version)))
409 		return 0;
410 
411 	if (v9inode->qid.type != st->qid.type)
412 		return 0;
413 
414 	if (v9inode->qid.path != st->qid.path)
415 		return 0;
416 	return 1;
417 }
418 
419 static int v9fs_test_new_inode(struct inode *inode, void *data)
420 {
421 	return 0;
422 }
423 
424 static int v9fs_set_inode(struct inode *inode,  void *data)
425 {
426 	struct v9fs_inode *v9inode = V9FS_I(inode);
427 	struct p9_wstat *st = (struct p9_wstat *)data;
428 
429 	memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
430 	return 0;
431 }
432 
433 static struct inode *v9fs_qid_iget(struct super_block *sb,
434 				   struct p9_qid *qid,
435 				   struct p9_wstat *st,
436 				   int new)
437 {
438 	dev_t rdev;
439 	int retval;
440 	umode_t umode;
441 	unsigned long i_ino;
442 	struct inode *inode;
443 	struct v9fs_session_info *v9ses = sb->s_fs_info;
444 	int (*test)(struct inode *inode, void *data);
445 
446 	if (new)
447 		test = v9fs_test_new_inode;
448 	else
449 		test = v9fs_test_inode;
450 
451 	i_ino = v9fs_qid2ino(qid);
452 	inode = iget5_locked(sb, i_ino, test, v9fs_set_inode, st);
453 	if (!inode)
454 		return ERR_PTR(-ENOMEM);
455 	if (!(inode->i_state & I_NEW))
456 		return inode;
457 	/*
458 	 * initialize the inode with the stat info
459 	 * FIXME!! we may need support for stale inodes
460 	 * later.
461 	 */
462 	inode->i_ino = i_ino;
463 	umode = p9mode2unixmode(v9ses, st, &rdev);
464 	retval = v9fs_init_inode(v9ses, inode, umode, rdev);
465 	if (retval)
466 		goto error;
467 
468 	v9fs_stat2inode(st, inode, sb, 0);
469 	v9fs_set_netfs_context(inode);
470 	v9fs_cache_inode_get_cookie(inode);
471 	unlock_new_inode(inode);
472 	return inode;
473 error:
474 	iget_failed(inode);
475 	return ERR_PTR(retval);
476 
477 }
478 
479 struct inode *
480 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
481 		    struct super_block *sb, int new)
482 {
483 	struct p9_wstat *st;
484 	struct inode *inode = NULL;
485 
486 	st = p9_client_stat(fid);
487 	if (IS_ERR(st))
488 		return ERR_CAST(st);
489 
490 	inode = v9fs_qid_iget(sb, &st->qid, st, new);
491 	p9stat_free(st);
492 	kfree(st);
493 	return inode;
494 }
495 
496 /**
497  * v9fs_at_to_dotl_flags- convert Linux specific AT flags to
498  * plan 9 AT flag.
499  * @flags: flags to convert
500  */
501 static int v9fs_at_to_dotl_flags(int flags)
502 {
503 	int rflags = 0;
504 
505 	if (flags & AT_REMOVEDIR)
506 		rflags |= P9_DOTL_AT_REMOVEDIR;
507 
508 	return rflags;
509 }
510 
511 /**
512  * v9fs_dec_count - helper functon to drop i_nlink.
513  *
514  * If a directory had nlink <= 2 (including . and ..), then we should not drop
515  * the link count, which indicates the underlying exported fs doesn't maintain
516  * nlink accurately. e.g.
517  * - overlayfs sets nlink to 1 for merged dir
518  * - ext4 (with dir_nlink feature enabled) sets nlink to 1 if a dir has more
519  *   than EXT4_LINK_MAX (65000) links.
520  *
521  * @inode: inode whose nlink is being dropped
522  */
523 static void v9fs_dec_count(struct inode *inode)
524 {
525 	if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
526 		drop_nlink(inode);
527 }
528 
529 /**
530  * v9fs_remove - helper function to remove files and directories
531  * @dir: directory inode that is being deleted
532  * @dentry:  dentry that is being deleted
533  * @flags: removing a directory
534  *
535  */
536 
537 static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
538 {
539 	struct inode *inode;
540 	int retval = -EOPNOTSUPP;
541 	struct p9_fid *v9fid, *dfid;
542 	struct v9fs_session_info *v9ses;
543 
544 	p9_debug(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
545 		 dir, dentry, flags);
546 
547 	v9ses = v9fs_inode2v9ses(dir);
548 	inode = d_inode(dentry);
549 	dfid = v9fs_parent_fid(dentry);
550 	if (IS_ERR(dfid)) {
551 		retval = PTR_ERR(dfid);
552 		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
553 		return retval;
554 	}
555 	if (v9fs_proto_dotl(v9ses))
556 		retval = p9_client_unlinkat(dfid, dentry->d_name.name,
557 					    v9fs_at_to_dotl_flags(flags));
558 	p9_fid_put(dfid);
559 	if (retval == -EOPNOTSUPP) {
560 		/* Try the one based on path */
561 		v9fid = v9fs_fid_clone(dentry);
562 		if (IS_ERR(v9fid))
563 			return PTR_ERR(v9fid);
564 		retval = p9_client_remove(v9fid);
565 	}
566 	if (!retval) {
567 		/*
568 		 * directories on unlink should have zero
569 		 * link count
570 		 */
571 		if (flags & AT_REMOVEDIR) {
572 			clear_nlink(inode);
573 			v9fs_dec_count(dir);
574 		} else
575 			v9fs_dec_count(inode);
576 
577 		v9fs_invalidate_inode_attr(inode);
578 		v9fs_invalidate_inode_attr(dir);
579 
580 		/* invalidate all fids associated with dentry */
581 		/* NOTE: This will not include open fids */
582 		dentry->d_op->d_release(dentry);
583 	}
584 	return retval;
585 }
586 
587 /**
588  * v9fs_create - Create a file
589  * @v9ses: session information
590  * @dir: directory that dentry is being created in
591  * @dentry:  dentry that is being created
592  * @extension: 9p2000.u extension string to support devices, etc.
593  * @perm: create permissions
594  * @mode: open mode
595  *
596  */
597 static struct p9_fid *
598 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
599 		struct dentry *dentry, char *extension, u32 perm, u8 mode)
600 {
601 	int err;
602 	const unsigned char *name;
603 	struct p9_fid *dfid, *ofid = NULL, *fid = NULL;
604 	struct inode *inode;
605 
606 	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
607 
608 	name = dentry->d_name.name;
609 	dfid = v9fs_parent_fid(dentry);
610 	if (IS_ERR(dfid)) {
611 		err = PTR_ERR(dfid);
612 		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
613 		return ERR_PTR(err);
614 	}
615 
616 	/* clone a fid to use for creation */
617 	ofid = clone_fid(dfid);
618 	if (IS_ERR(ofid)) {
619 		err = PTR_ERR(ofid);
620 		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
621 		goto error;
622 	}
623 
624 	err = p9_client_fcreate(ofid, name, perm, mode, extension);
625 	if (err < 0) {
626 		p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
627 		goto error;
628 	}
629 
630 	if (!(perm & P9_DMLINK)) {
631 		/* now walk from the parent so we can get unopened fid */
632 		fid = p9_client_walk(dfid, 1, &name, 1);
633 		if (IS_ERR(fid)) {
634 			err = PTR_ERR(fid);
635 			p9_debug(P9_DEBUG_VFS,
636 				   "p9_client_walk failed %d\n", err);
637 			goto error;
638 		}
639 		/*
640 		 * instantiate inode and assign the unopened fid to the dentry
641 		 */
642 		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
643 		if (IS_ERR(inode)) {
644 			err = PTR_ERR(inode);
645 			p9_debug(P9_DEBUG_VFS,
646 				   "inode creation failed %d\n", err);
647 			goto error;
648 		}
649 		v9fs_fid_add(dentry, &fid);
650 		d_instantiate(dentry, inode);
651 	}
652 	p9_fid_put(dfid);
653 	return ofid;
654 error:
655 	p9_fid_put(dfid);
656 	p9_fid_put(ofid);
657 	p9_fid_put(fid);
658 	return ERR_PTR(err);
659 }
660 
661 /**
662  * v9fs_vfs_create - VFS hook to create a regular file
663  * @idmap: idmap of the mount
664  * @dir: The parent directory
665  * @dentry: The name of file to be created
666  * @mode: The UNIX file mode to set
667  * @excl: True if the file must not yet exist
668  *
669  * open(.., O_CREAT) is handled in v9fs_vfs_atomic_open().  This is only called
670  * for mknod(2).
671  *
672  */
673 
674 static int
675 v9fs_vfs_create(struct mnt_idmap *idmap, struct inode *dir,
676 		struct dentry *dentry, umode_t mode, bool excl)
677 {
678 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
679 	u32 perm = unixmode2p9mode(v9ses, mode);
680 	struct p9_fid *fid;
681 
682 	/* P9_OEXCL? */
683 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_ORDWR);
684 	if (IS_ERR(fid))
685 		return PTR_ERR(fid);
686 
687 	v9fs_invalidate_inode_attr(dir);
688 	p9_fid_put(fid);
689 
690 	return 0;
691 }
692 
693 /**
694  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
695  * @idmap: idmap of the mount
696  * @dir:  inode that is being unlinked
697  * @dentry: dentry that is being unlinked
698  * @mode: mode for new directory
699  *
700  */
701 
702 static int v9fs_vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
703 			  struct dentry *dentry, umode_t mode)
704 {
705 	int err;
706 	u32 perm;
707 	struct p9_fid *fid;
708 	struct v9fs_session_info *v9ses;
709 
710 	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
711 	err = 0;
712 	v9ses = v9fs_inode2v9ses(dir);
713 	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
714 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
715 	if (IS_ERR(fid)) {
716 		err = PTR_ERR(fid);
717 		fid = NULL;
718 	} else {
719 		inc_nlink(dir);
720 		v9fs_invalidate_inode_attr(dir);
721 	}
722 
723 	if (fid)
724 		p9_fid_put(fid);
725 
726 	return err;
727 }
728 
729 /**
730  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
731  * @dir:  inode that is being walked from
732  * @dentry: dentry that is being walked to?
733  * @flags: lookup flags (unused)
734  *
735  */
736 
737 struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
738 				      unsigned int flags)
739 {
740 	struct dentry *res;
741 	struct v9fs_session_info *v9ses;
742 	struct p9_fid *dfid, *fid;
743 	struct inode *inode;
744 	const unsigned char *name;
745 
746 	p9_debug(P9_DEBUG_VFS, "dir: %p dentry: (%pd) %p flags: %x\n",
747 		 dir, dentry, dentry, flags);
748 
749 	if (dentry->d_name.len > NAME_MAX)
750 		return ERR_PTR(-ENAMETOOLONG);
751 
752 	v9ses = v9fs_inode2v9ses(dir);
753 	/* We can walk d_parent because we hold the dir->i_mutex */
754 	dfid = v9fs_parent_fid(dentry);
755 	if (IS_ERR(dfid))
756 		return ERR_CAST(dfid);
757 
758 	/*
759 	 * Make sure we don't use a wrong inode due to parallel
760 	 * unlink. For cached mode create calls request for new
761 	 * inode. But with cache disabled, lookup should do this.
762 	 */
763 	name = dentry->d_name.name;
764 	fid = p9_client_walk(dfid, 1, &name, 1);
765 	p9_fid_put(dfid);
766 	if (fid == ERR_PTR(-ENOENT))
767 		inode = NULL;
768 	else if (IS_ERR(fid))
769 		inode = ERR_CAST(fid);
770 	else if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
771 		inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
772 	else
773 		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
774 	/*
775 	 * If we had a rename on the server and a parallel lookup
776 	 * for the new name, then make sure we instantiate with
777 	 * the new name. ie look up for a/b, while on server somebody
778 	 * moved b under k and client parallely did a lookup for
779 	 * k/b.
780 	 */
781 	res = d_splice_alias(inode, dentry);
782 	if (!IS_ERR(fid)) {
783 		if (!res)
784 			v9fs_fid_add(dentry, &fid);
785 		else if (!IS_ERR(res))
786 			v9fs_fid_add(res, &fid);
787 		else
788 			p9_fid_put(fid);
789 	}
790 	return res;
791 }
792 
793 static int
794 v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
795 		     struct file *file, unsigned int flags, umode_t mode)
796 {
797 	int err;
798 	u32 perm;
799 	struct v9fs_inode __maybe_unused *v9inode;
800 	struct v9fs_session_info *v9ses;
801 	struct p9_fid *fid;
802 	struct dentry *res = NULL;
803 	struct inode *inode;
804 	int p9_omode;
805 
806 	if (d_in_lookup(dentry)) {
807 		res = v9fs_vfs_lookup(dir, dentry, 0);
808 		if (IS_ERR(res))
809 			return PTR_ERR(res);
810 
811 		if (res)
812 			dentry = res;
813 	}
814 
815 	/* Only creates */
816 	if (!(flags & O_CREAT) || d_really_is_positive(dentry))
817 		return finish_no_open(file, res);
818 
819 	v9ses = v9fs_inode2v9ses(dir);
820 	perm = unixmode2p9mode(v9ses, mode);
821 	p9_omode = v9fs_uflags2omode(flags, v9fs_proto_dotu(v9ses));
822 
823 	if ((v9ses->cache & CACHE_WRITEBACK) && (p9_omode & P9_OWRITE)) {
824 		p9_omode = (p9_omode & ~P9_OWRITE) | P9_ORDWR;
825 		p9_debug(P9_DEBUG_CACHE,
826 			"write-only file with writeback enabled, creating w/ O_RDWR\n");
827 	}
828 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, p9_omode);
829 	if (IS_ERR(fid)) {
830 		err = PTR_ERR(fid);
831 		goto error;
832 	}
833 
834 	v9fs_invalidate_inode_attr(dir);
835 	inode = d_inode(dentry);
836 	v9inode = V9FS_I(inode);
837 	err = finish_open(file, dentry, generic_file_open);
838 	if (err)
839 		goto error;
840 
841 	file->private_data = fid;
842 #ifdef CONFIG_9P_FSCACHE
843 	if (v9ses->cache & CACHE_FSCACHE)
844 		fscache_use_cookie(v9fs_inode_cookie(v9inode),
845 				   file->f_mode & FMODE_WRITE);
846 #endif
847 
848 	v9fs_fid_add_modes(fid, v9ses->flags, v9ses->cache, file->f_flags);
849 	v9fs_open_fid_add(inode, &fid);
850 
851 	file->f_mode |= FMODE_CREATED;
852 out:
853 	dput(res);
854 	return err;
855 
856 error:
857 	p9_fid_put(fid);
858 	goto out;
859 }
860 
861 /**
862  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
863  * @i:  inode that is being unlinked
864  * @d: dentry that is being unlinked
865  *
866  */
867 
868 int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
869 {
870 	return v9fs_remove(i, d, 0);
871 }
872 
873 /**
874  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
875  * @i:  inode that is being unlinked
876  * @d: dentry that is being unlinked
877  *
878  */
879 
880 int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
881 {
882 	return v9fs_remove(i, d, AT_REMOVEDIR);
883 }
884 
885 /**
886  * v9fs_vfs_rename - VFS hook to rename an inode
887  * @idmap: The idmap of the mount
888  * @old_dir:  old dir inode
889  * @old_dentry: old dentry
890  * @new_dir: new dir inode
891  * @new_dentry: new dentry
892  * @flags: RENAME_* flags
893  *
894  */
895 
896 int
897 v9fs_vfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
898 		struct dentry *old_dentry, struct inode *new_dir,
899 		struct dentry *new_dentry, unsigned int flags)
900 {
901 	int retval;
902 	struct inode *old_inode;
903 	struct inode *new_inode;
904 	struct v9fs_session_info *v9ses;
905 	struct p9_fid *oldfid = NULL, *dfid = NULL;
906 	struct p9_fid *olddirfid = NULL;
907 	struct p9_fid *newdirfid = NULL;
908 	struct p9_wstat wstat;
909 
910 	if (flags)
911 		return -EINVAL;
912 
913 	p9_debug(P9_DEBUG_VFS, "\n");
914 	old_inode = d_inode(old_dentry);
915 	new_inode = d_inode(new_dentry);
916 	v9ses = v9fs_inode2v9ses(old_inode);
917 	oldfid = v9fs_fid_lookup(old_dentry);
918 	if (IS_ERR(oldfid))
919 		return PTR_ERR(oldfid);
920 
921 	dfid = v9fs_parent_fid(old_dentry);
922 	olddirfid = clone_fid(dfid);
923 	p9_fid_put(dfid);
924 	dfid = NULL;
925 
926 	if (IS_ERR(olddirfid)) {
927 		retval = PTR_ERR(olddirfid);
928 		goto error;
929 	}
930 
931 	dfid = v9fs_parent_fid(new_dentry);
932 	newdirfid = clone_fid(dfid);
933 	p9_fid_put(dfid);
934 	dfid = NULL;
935 
936 	if (IS_ERR(newdirfid)) {
937 		retval = PTR_ERR(newdirfid);
938 		goto error;
939 	}
940 
941 	down_write(&v9ses->rename_sem);
942 	if (v9fs_proto_dotl(v9ses)) {
943 		retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
944 					    newdirfid, new_dentry->d_name.name);
945 		if (retval == -EOPNOTSUPP)
946 			retval = p9_client_rename(oldfid, newdirfid,
947 						  new_dentry->d_name.name);
948 		if (retval != -EOPNOTSUPP)
949 			goto error_locked;
950 	}
951 	if (old_dentry->d_parent != new_dentry->d_parent) {
952 		/*
953 		 * 9P .u can only handle file rename in the same directory
954 		 */
955 
956 		p9_debug(P9_DEBUG_ERROR, "old dir and new dir are different\n");
957 		retval = -EXDEV;
958 		goto error_locked;
959 	}
960 	v9fs_blank_wstat(&wstat);
961 	wstat.muid = v9ses->uname;
962 	wstat.name = new_dentry->d_name.name;
963 	retval = p9_client_wstat(oldfid, &wstat);
964 
965 error_locked:
966 	if (!retval) {
967 		if (new_inode) {
968 			if (S_ISDIR(new_inode->i_mode))
969 				clear_nlink(new_inode);
970 			else
971 				v9fs_dec_count(new_inode);
972 		}
973 		if (S_ISDIR(old_inode->i_mode)) {
974 			if (!new_inode)
975 				inc_nlink(new_dir);
976 			v9fs_dec_count(old_dir);
977 		}
978 		v9fs_invalidate_inode_attr(old_inode);
979 		v9fs_invalidate_inode_attr(old_dir);
980 		v9fs_invalidate_inode_attr(new_dir);
981 
982 		/* successful rename */
983 		d_move(old_dentry, new_dentry);
984 	}
985 	up_write(&v9ses->rename_sem);
986 
987 error:
988 	p9_fid_put(newdirfid);
989 	p9_fid_put(olddirfid);
990 	p9_fid_put(oldfid);
991 	return retval;
992 }
993 
994 /**
995  * v9fs_vfs_getattr - retrieve file metadata
996  * @idmap: idmap of the mount
997  * @path: Object to query
998  * @stat: metadata structure to populate
999  * @request_mask: Mask of STATX_xxx flags indicating the caller's interests
1000  * @flags: AT_STATX_xxx setting
1001  *
1002  */
1003 
1004 static int
1005 v9fs_vfs_getattr(struct mnt_idmap *idmap, const struct path *path,
1006 		 struct kstat *stat, u32 request_mask, unsigned int flags)
1007 {
1008 	struct dentry *dentry = path->dentry;
1009 	struct inode *inode = d_inode(dentry);
1010 	struct v9fs_session_info *v9ses;
1011 	struct p9_fid *fid;
1012 	struct p9_wstat *st;
1013 
1014 	p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
1015 	v9ses = v9fs_dentry2v9ses(dentry);
1016 	if (v9ses->cache & (CACHE_META|CACHE_LOOSE)) {
1017 		generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
1018 		return 0;
1019 	} else if (v9ses->cache & CACHE_WRITEBACK) {
1020 		if (S_ISREG(inode->i_mode)) {
1021 			int retval = filemap_fdatawrite(inode->i_mapping);
1022 
1023 			if (retval)
1024 				p9_debug(P9_DEBUG_ERROR,
1025 				    "flushing writeback during getattr returned %d\n", retval);
1026 		}
1027 	}
1028 	fid = v9fs_fid_lookup(dentry);
1029 	if (IS_ERR(fid))
1030 		return PTR_ERR(fid);
1031 
1032 	st = p9_client_stat(fid);
1033 	p9_fid_put(fid);
1034 	if (IS_ERR(st))
1035 		return PTR_ERR(st);
1036 
1037 	v9fs_stat2inode(st, d_inode(dentry), dentry->d_sb, 0);
1038 	generic_fillattr(&nop_mnt_idmap, request_mask, d_inode(dentry), stat);
1039 
1040 	p9stat_free(st);
1041 	kfree(st);
1042 	return 0;
1043 }
1044 
1045 /**
1046  * v9fs_vfs_setattr - set file metadata
1047  * @idmap: idmap of the mount
1048  * @dentry: file whose metadata to set
1049  * @iattr: metadata assignment structure
1050  *
1051  */
1052 
1053 static int v9fs_vfs_setattr(struct mnt_idmap *idmap,
1054 			    struct dentry *dentry, struct iattr *iattr)
1055 {
1056 	int retval, use_dentry = 0;
1057 	struct inode *inode = d_inode(dentry);
1058 	struct v9fs_session_info *v9ses;
1059 	struct p9_fid *fid = NULL;
1060 	struct p9_wstat wstat;
1061 
1062 	p9_debug(P9_DEBUG_VFS, "\n");
1063 	retval = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
1064 	if (retval)
1065 		return retval;
1066 
1067 	v9ses = v9fs_dentry2v9ses(dentry);
1068 	if (iattr->ia_valid & ATTR_FILE) {
1069 		fid = iattr->ia_file->private_data;
1070 		WARN_ON(!fid);
1071 	}
1072 	if (!fid) {
1073 		fid = v9fs_fid_lookup(dentry);
1074 		use_dentry = 1;
1075 	}
1076 	if (IS_ERR(fid))
1077 		return PTR_ERR(fid);
1078 
1079 	v9fs_blank_wstat(&wstat);
1080 	if (iattr->ia_valid & ATTR_MODE)
1081 		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
1082 
1083 	if (iattr->ia_valid & ATTR_MTIME)
1084 		wstat.mtime = iattr->ia_mtime.tv_sec;
1085 
1086 	if (iattr->ia_valid & ATTR_ATIME)
1087 		wstat.atime = iattr->ia_atime.tv_sec;
1088 
1089 	if (iattr->ia_valid & ATTR_SIZE)
1090 		wstat.length = iattr->ia_size;
1091 
1092 	if (v9fs_proto_dotu(v9ses)) {
1093 		if (iattr->ia_valid & ATTR_UID)
1094 			wstat.n_uid = iattr->ia_uid;
1095 
1096 		if (iattr->ia_valid & ATTR_GID)
1097 			wstat.n_gid = iattr->ia_gid;
1098 	}
1099 
1100 	/* Write all dirty data */
1101 	if (d_is_reg(dentry)) {
1102 		retval = filemap_fdatawrite(inode->i_mapping);
1103 		if (retval)
1104 			p9_debug(P9_DEBUG_ERROR,
1105 			    "flushing writeback during setattr returned %d\n", retval);
1106 	}
1107 
1108 	retval = p9_client_wstat(fid, &wstat);
1109 
1110 	if (use_dentry)
1111 		p9_fid_put(fid);
1112 
1113 	if (retval < 0)
1114 		return retval;
1115 
1116 	if ((iattr->ia_valid & ATTR_SIZE) &&
1117 		 iattr->ia_size != i_size_read(inode)) {
1118 		truncate_setsize(inode, iattr->ia_size);
1119 		truncate_pagecache(inode, iattr->ia_size);
1120 
1121 #ifdef CONFIG_9P_FSCACHE
1122 		if (v9ses->cache & CACHE_FSCACHE) {
1123 			struct v9fs_inode *v9inode = V9FS_I(inode);
1124 
1125 			fscache_resize_cookie(v9fs_inode_cookie(v9inode), iattr->ia_size);
1126 		}
1127 #endif
1128 	}
1129 
1130 	v9fs_invalidate_inode_attr(inode);
1131 
1132 	setattr_copy(&nop_mnt_idmap, inode, iattr);
1133 	mark_inode_dirty(inode);
1134 	return 0;
1135 }
1136 
1137 /**
1138  * v9fs_stat2inode - populate an inode structure with mistat info
1139  * @stat: Plan 9 metadata (mistat) structure
1140  * @inode: inode to populate
1141  * @sb: superblock of filesystem
1142  * @flags: control flags (e.g. V9FS_STAT2INODE_KEEP_ISIZE)
1143  *
1144  */
1145 
1146 void
1147 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
1148 		 struct super_block *sb, unsigned int flags)
1149 {
1150 	umode_t mode;
1151 	struct v9fs_session_info *v9ses = sb->s_fs_info;
1152 	struct v9fs_inode *v9inode = V9FS_I(inode);
1153 
1154 	set_nlink(inode, 1);
1155 
1156 	inode->i_atime.tv_sec = stat->atime;
1157 	inode->i_mtime.tv_sec = stat->mtime;
1158 	inode_set_ctime(inode, stat->mtime, 0);
1159 
1160 	inode->i_uid = v9ses->dfltuid;
1161 	inode->i_gid = v9ses->dfltgid;
1162 
1163 	if (v9fs_proto_dotu(v9ses)) {
1164 		inode->i_uid = stat->n_uid;
1165 		inode->i_gid = stat->n_gid;
1166 	}
1167 	if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
1168 		if (v9fs_proto_dotu(v9ses)) {
1169 			unsigned int i_nlink;
1170 			/*
1171 			 * Hadlink support got added later to the .u extension.
1172 			 * So there can be a server out there that doesn't
1173 			 * support this even with .u extension. That would
1174 			 * just leave us with stat->extension being an empty
1175 			 * string, though.
1176 			 */
1177 			/* HARDLINKCOUNT %u */
1178 			if (sscanf(stat->extension,
1179 				   " HARDLINKCOUNT %u", &i_nlink) == 1)
1180 				set_nlink(inode, i_nlink);
1181 		}
1182 	}
1183 	mode = p9mode2perm(v9ses, stat);
1184 	mode |= inode->i_mode & ~S_IALLUGO;
1185 	inode->i_mode = mode;
1186 
1187 	if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
1188 		v9fs_i_size_write(inode, stat->length);
1189 	/* not real number of blocks, but 512 byte ones ... */
1190 	inode->i_blocks = (stat->length + 512 - 1) >> 9;
1191 	v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
1192 }
1193 
1194 /**
1195  * v9fs_qid2ino - convert qid into inode number
1196  * @qid: qid to hash
1197  *
1198  * BUG: potential for inode number collisions?
1199  */
1200 
1201 ino_t v9fs_qid2ino(struct p9_qid *qid)
1202 {
1203 	u64 path = qid->path + 2;
1204 	ino_t i = 0;
1205 
1206 	if (sizeof(ino_t) == sizeof(path))
1207 		memcpy(&i, &path, sizeof(ino_t));
1208 	else
1209 		i = (ino_t) (path ^ (path >> 32));
1210 
1211 	return i;
1212 }
1213 
1214 /**
1215  * v9fs_vfs_get_link - follow a symlink path
1216  * @dentry: dentry for symlink
1217  * @inode: inode for symlink
1218  * @done: delayed call for when we are done with the return value
1219  */
1220 
1221 static const char *v9fs_vfs_get_link(struct dentry *dentry,
1222 				     struct inode *inode,
1223 				     struct delayed_call *done)
1224 {
1225 	struct v9fs_session_info *v9ses;
1226 	struct p9_fid *fid;
1227 	struct p9_wstat *st;
1228 	char *res;
1229 
1230 	if (!dentry)
1231 		return ERR_PTR(-ECHILD);
1232 
1233 	v9ses = v9fs_dentry2v9ses(dentry);
1234 	if (!v9fs_proto_dotu(v9ses))
1235 		return ERR_PTR(-EBADF);
1236 
1237 	p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
1238 	fid = v9fs_fid_lookup(dentry);
1239 
1240 	if (IS_ERR(fid))
1241 		return ERR_CAST(fid);
1242 
1243 	st = p9_client_stat(fid);
1244 	p9_fid_put(fid);
1245 	if (IS_ERR(st))
1246 		return ERR_CAST(st);
1247 
1248 	if (!(st->mode & P9_DMSYMLINK)) {
1249 		p9stat_free(st);
1250 		kfree(st);
1251 		return ERR_PTR(-EINVAL);
1252 	}
1253 	res = st->extension;
1254 	st->extension = NULL;
1255 	if (strlen(res) >= PATH_MAX)
1256 		res[PATH_MAX - 1] = '\0';
1257 
1258 	p9stat_free(st);
1259 	kfree(st);
1260 	set_delayed_call(done, kfree_link, res);
1261 	return res;
1262 }
1263 
1264 /**
1265  * v9fs_vfs_mkspecial - create a special file
1266  * @dir: inode to create special file in
1267  * @dentry: dentry to create
1268  * @perm: mode to create special file
1269  * @extension: 9p2000.u format extension string representing special file
1270  *
1271  */
1272 
1273 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1274 	u32 perm, const char *extension)
1275 {
1276 	struct p9_fid *fid;
1277 	struct v9fs_session_info *v9ses;
1278 
1279 	v9ses = v9fs_inode2v9ses(dir);
1280 	if (!v9fs_proto_dotu(v9ses)) {
1281 		p9_debug(P9_DEBUG_ERROR, "not extended\n");
1282 		return -EPERM;
1283 	}
1284 
1285 	fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1286 								P9_OREAD);
1287 	if (IS_ERR(fid))
1288 		return PTR_ERR(fid);
1289 
1290 	v9fs_invalidate_inode_attr(dir);
1291 	p9_fid_put(fid);
1292 	return 0;
1293 }
1294 
1295 /**
1296  * v9fs_vfs_symlink - helper function to create symlinks
1297  * @idmap: idmap of the mount
1298  * @dir: directory inode containing symlink
1299  * @dentry: dentry for symlink
1300  * @symname: symlink data
1301  *
1302  * See Also: 9P2000.u RFC for more information
1303  *
1304  */
1305 
1306 static int
1307 v9fs_vfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
1308 		 struct dentry *dentry, const char *symname)
1309 {
1310 	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%s\n",
1311 		 dir->i_ino, dentry, symname);
1312 
1313 	return v9fs_vfs_mkspecial(dir, dentry, P9_DMSYMLINK, symname);
1314 }
1315 
1316 #define U32_MAX_DIGITS 10
1317 
1318 /**
1319  * v9fs_vfs_link - create a hardlink
1320  * @old_dentry: dentry for file to link to
1321  * @dir: inode destination for new link
1322  * @dentry: dentry for link
1323  *
1324  */
1325 
1326 static int
1327 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1328 	      struct dentry *dentry)
1329 {
1330 	int retval;
1331 	char name[1 + U32_MAX_DIGITS + 2]; /* sign + number + \n + \0 */
1332 	struct p9_fid *oldfid;
1333 
1334 	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%pd\n",
1335 		 dir->i_ino, dentry, old_dentry);
1336 
1337 	oldfid = v9fs_fid_clone(old_dentry);
1338 	if (IS_ERR(oldfid))
1339 		return PTR_ERR(oldfid);
1340 
1341 	sprintf(name, "%d\n", oldfid->fid);
1342 	retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1343 	if (!retval) {
1344 		v9fs_refresh_inode(oldfid, d_inode(old_dentry));
1345 		v9fs_invalidate_inode_attr(dir);
1346 	}
1347 	p9_fid_put(oldfid);
1348 	return retval;
1349 }
1350 
1351 /**
1352  * v9fs_vfs_mknod - create a special file
1353  * @idmap: idmap of the mount
1354  * @dir: inode destination for new link
1355  * @dentry: dentry for file
1356  * @mode: mode for creation
1357  * @rdev: device associated with special file
1358  *
1359  */
1360 
1361 static int
1362 v9fs_vfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
1363 	       struct dentry *dentry, umode_t mode, dev_t rdev)
1364 {
1365 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
1366 	int retval;
1367 	char name[2 + U32_MAX_DIGITS + 1 + U32_MAX_DIGITS + 1];
1368 	u32 perm;
1369 
1370 	p9_debug(P9_DEBUG_VFS, " %lu,%pd mode: %x MAJOR: %u MINOR: %u\n",
1371 		 dir->i_ino, dentry, mode,
1372 		 MAJOR(rdev), MINOR(rdev));
1373 
1374 	/* build extension */
1375 	if (S_ISBLK(mode))
1376 		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1377 	else if (S_ISCHR(mode))
1378 		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1379 	else
1380 		*name = 0;
1381 
1382 	perm = unixmode2p9mode(v9ses, mode);
1383 	retval = v9fs_vfs_mkspecial(dir, dentry, perm, name);
1384 
1385 	return retval;
1386 }
1387 
1388 int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
1389 {
1390 	int umode;
1391 	dev_t rdev;
1392 	struct p9_wstat *st;
1393 	struct v9fs_session_info *v9ses;
1394 	unsigned int flags;
1395 
1396 	v9ses = v9fs_inode2v9ses(inode);
1397 	st = p9_client_stat(fid);
1398 	if (IS_ERR(st))
1399 		return PTR_ERR(st);
1400 	/*
1401 	 * Don't update inode if the file type is different
1402 	 */
1403 	umode = p9mode2unixmode(v9ses, st, &rdev);
1404 	if (inode_wrong_type(inode, umode))
1405 		goto out;
1406 
1407 	/*
1408 	 * We don't want to refresh inode->i_size,
1409 	 * because we may have cached data
1410 	 */
1411 	flags = (v9ses->cache & CACHE_LOOSE) ?
1412 		V9FS_STAT2INODE_KEEP_ISIZE : 0;
1413 	v9fs_stat2inode(st, inode, inode->i_sb, flags);
1414 out:
1415 	p9stat_free(st);
1416 	kfree(st);
1417 	return 0;
1418 }
1419 
1420 static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1421 	.create = v9fs_vfs_create,
1422 	.lookup = v9fs_vfs_lookup,
1423 	.atomic_open = v9fs_vfs_atomic_open,
1424 	.symlink = v9fs_vfs_symlink,
1425 	.link = v9fs_vfs_link,
1426 	.unlink = v9fs_vfs_unlink,
1427 	.mkdir = v9fs_vfs_mkdir,
1428 	.rmdir = v9fs_vfs_rmdir,
1429 	.mknod = v9fs_vfs_mknod,
1430 	.rename = v9fs_vfs_rename,
1431 	.getattr = v9fs_vfs_getattr,
1432 	.setattr = v9fs_vfs_setattr,
1433 };
1434 
1435 static const struct inode_operations v9fs_dir_inode_operations = {
1436 	.create = v9fs_vfs_create,
1437 	.lookup = v9fs_vfs_lookup,
1438 	.atomic_open = v9fs_vfs_atomic_open,
1439 	.unlink = v9fs_vfs_unlink,
1440 	.mkdir = v9fs_vfs_mkdir,
1441 	.rmdir = v9fs_vfs_rmdir,
1442 	.mknod = v9fs_vfs_mknod,
1443 	.rename = v9fs_vfs_rename,
1444 	.getattr = v9fs_vfs_getattr,
1445 	.setattr = v9fs_vfs_setattr,
1446 };
1447 
1448 static const struct inode_operations v9fs_file_inode_operations = {
1449 	.getattr = v9fs_vfs_getattr,
1450 	.setattr = v9fs_vfs_setattr,
1451 };
1452 
1453 static const struct inode_operations v9fs_symlink_inode_operations = {
1454 	.get_link = v9fs_vfs_get_link,
1455 	.getattr = v9fs_vfs_getattr,
1456 	.setattr = v9fs_vfs_setattr,
1457 };
1458 
1459