xref: /linux/fs/9p/vfs_inode.c (revision 850925a8133c73c4a2453c360b2c3beb3bab67c9)
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 
unixmode2p9mode(struct v9fs_session_info * v9ses,umode_t mode)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  */
p9mode2perm(struct v9fs_session_info * v9ses,struct p9_wstat * stat)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  */
p9mode2unixmode(struct v9fs_session_info * v9ses,struct p9_wstat * stat,dev_t * rdev)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 
v9fs_uflags2omode(int uflags,int extended)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
v9fs_blank_wstat(struct p9_wstat * wstat)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  */
v9fs_alloc_inode(struct super_block * sb)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 
v9fs_free_inode(struct inode * inode)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  */
v9fs_set_netfs_context(struct inode * inode)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 
v9fs_init_inode(struct v9fs_session_info * v9ses,struct inode * inode,umode_t mode,dev_t rdev)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 		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_evict_inode - Remove an inode from the inode cache
339  * @inode: inode to release
340  *
341  */
v9fs_evict_inode(struct inode * inode)342 void v9fs_evict_inode(struct inode *inode)
343 {
344 	struct v9fs_inode __maybe_unused *v9inode = V9FS_I(inode);
345 	__le32 __maybe_unused version;
346 
347 	if (!is_bad_inode(inode)) {
348 		netfs_wait_for_outstanding_io(inode);
349 		truncate_inode_pages_final(&inode->i_data);
350 
351 		version = cpu_to_le32(v9inode->qid.version);
352 		netfs_clear_inode_writeback(inode, &version);
353 
354 		clear_inode(inode);
355 		filemap_fdatawrite(&inode->i_data);
356 
357 #ifdef CONFIG_9P_FSCACHE
358 		if (v9fs_inode_cookie(v9inode))
359 			fscache_relinquish_cookie(v9fs_inode_cookie(v9inode), false);
360 #endif
361 	} else
362 		clear_inode(inode);
363 }
364 
v9fs_test_inode(struct inode * inode,void * data)365 static int v9fs_test_inode(struct inode *inode, void *data)
366 {
367 	int umode;
368 	dev_t rdev;
369 	struct v9fs_inode *v9inode = V9FS_I(inode);
370 	struct p9_wstat *st = (struct p9_wstat *)data;
371 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
372 
373 	umode = p9mode2unixmode(v9ses, st, &rdev);
374 	/* don't match inode of different type */
375 	if (inode_wrong_type(inode, umode))
376 		return 0;
377 
378 	/* compare qid details */
379 	if (memcmp(&v9inode->qid.version,
380 		   &st->qid.version, sizeof(v9inode->qid.version)))
381 		return 0;
382 
383 	if (v9inode->qid.type != st->qid.type)
384 		return 0;
385 
386 	if (v9inode->qid.path != st->qid.path)
387 		return 0;
388 	return 1;
389 }
390 
v9fs_test_new_inode(struct inode * inode,void * data)391 static int v9fs_test_new_inode(struct inode *inode, void *data)
392 {
393 	return 0;
394 }
395 
v9fs_set_inode(struct inode * inode,void * data)396 static int v9fs_set_inode(struct inode *inode,  void *data)
397 {
398 	struct v9fs_inode *v9inode = V9FS_I(inode);
399 	struct p9_wstat *st = (struct p9_wstat *)data;
400 
401 	memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
402 	return 0;
403 }
404 
v9fs_qid_iget(struct super_block * sb,struct p9_qid * qid,struct p9_wstat * st,int new)405 static struct inode *v9fs_qid_iget(struct super_block *sb,
406 				   struct p9_qid *qid,
407 				   struct p9_wstat *st,
408 				   int new)
409 {
410 	dev_t rdev;
411 	int retval;
412 	umode_t umode;
413 	struct inode *inode;
414 	struct v9fs_session_info *v9ses = sb->s_fs_info;
415 	int (*test)(struct inode *inode, void *data);
416 
417 	if (new)
418 		test = v9fs_test_new_inode;
419 	else
420 		test = v9fs_test_inode;
421 
422 	inode = iget5_locked(sb, QID2INO(qid), test, v9fs_set_inode, st);
423 	if (!inode)
424 		return ERR_PTR(-ENOMEM);
425 	if (!(inode->i_state & I_NEW))
426 		return inode;
427 	/*
428 	 * initialize the inode with the stat info
429 	 * FIXME!! we may need support for stale inodes
430 	 * later.
431 	 */
432 	inode->i_ino = QID2INO(qid);
433 	umode = p9mode2unixmode(v9ses, st, &rdev);
434 	retval = v9fs_init_inode(v9ses, inode, umode, rdev);
435 	if (retval)
436 		goto error;
437 
438 	v9fs_stat2inode(st, inode, sb, 0);
439 	v9fs_set_netfs_context(inode);
440 	v9fs_cache_inode_get_cookie(inode);
441 	unlock_new_inode(inode);
442 	return inode;
443 error:
444 	iget_failed(inode);
445 	return ERR_PTR(retval);
446 
447 }
448 
449 struct inode *
v9fs_inode_from_fid(struct v9fs_session_info * v9ses,struct p9_fid * fid,struct super_block * sb,int new)450 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
451 		    struct super_block *sb, int new)
452 {
453 	struct p9_wstat *st;
454 	struct inode *inode = NULL;
455 
456 	st = p9_client_stat(fid);
457 	if (IS_ERR(st))
458 		return ERR_CAST(st);
459 
460 	inode = v9fs_qid_iget(sb, &st->qid, st, new);
461 	p9stat_free(st);
462 	kfree(st);
463 	return inode;
464 }
465 
466 /**
467  * v9fs_at_to_dotl_flags- convert Linux specific AT flags to
468  * plan 9 AT flag.
469  * @flags: flags to convert
470  */
v9fs_at_to_dotl_flags(int flags)471 static int v9fs_at_to_dotl_flags(int flags)
472 {
473 	int rflags = 0;
474 
475 	if (flags & AT_REMOVEDIR)
476 		rflags |= P9_DOTL_AT_REMOVEDIR;
477 
478 	return rflags;
479 }
480 
481 /**
482  * v9fs_dec_count - helper functon to drop i_nlink.
483  *
484  * If a directory had nlink <= 2 (including . and ..), then we should not drop
485  * the link count, which indicates the underlying exported fs doesn't maintain
486  * nlink accurately. e.g.
487  * - overlayfs sets nlink to 1 for merged dir
488  * - ext4 (with dir_nlink feature enabled) sets nlink to 1 if a dir has more
489  *   than EXT4_LINK_MAX (65000) links.
490  *
491  * @inode: inode whose nlink is being dropped
492  */
v9fs_dec_count(struct inode * inode)493 static void v9fs_dec_count(struct inode *inode)
494 {
495 	if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
496 		drop_nlink(inode);
497 }
498 
499 /**
500  * v9fs_remove - helper function to remove files and directories
501  * @dir: directory inode that is being deleted
502  * @dentry:  dentry that is being deleted
503  * @flags: removing a directory
504  *
505  */
506 
v9fs_remove(struct inode * dir,struct dentry * dentry,int flags)507 static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
508 {
509 	struct inode *inode;
510 	int retval = -EOPNOTSUPP;
511 	struct p9_fid *v9fid, *dfid;
512 	struct v9fs_session_info *v9ses;
513 
514 	p9_debug(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
515 		 dir, dentry, flags);
516 
517 	v9ses = v9fs_inode2v9ses(dir);
518 	inode = d_inode(dentry);
519 	dfid = v9fs_parent_fid(dentry);
520 	if (IS_ERR(dfid)) {
521 		retval = PTR_ERR(dfid);
522 		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
523 		return retval;
524 	}
525 	if (v9fs_proto_dotl(v9ses))
526 		retval = p9_client_unlinkat(dfid, dentry->d_name.name,
527 					    v9fs_at_to_dotl_flags(flags));
528 	p9_fid_put(dfid);
529 	if (retval == -EOPNOTSUPP) {
530 		/* Try the one based on path */
531 		v9fid = v9fs_fid_clone(dentry);
532 		if (IS_ERR(v9fid))
533 			return PTR_ERR(v9fid);
534 		retval = p9_client_remove(v9fid);
535 	}
536 	if (!retval) {
537 		/*
538 		 * directories on unlink should have zero
539 		 * link count
540 		 */
541 		if (flags & AT_REMOVEDIR) {
542 			clear_nlink(inode);
543 			v9fs_dec_count(dir);
544 		} else
545 			v9fs_dec_count(inode);
546 
547 		v9fs_invalidate_inode_attr(inode);
548 		v9fs_invalidate_inode_attr(dir);
549 
550 		/* invalidate all fids associated with dentry */
551 		/* NOTE: This will not include open fids */
552 		dentry->d_op->d_release(dentry);
553 	}
554 	return retval;
555 }
556 
557 /**
558  * v9fs_create - Create a file
559  * @v9ses: session information
560  * @dir: directory that dentry is being created in
561  * @dentry:  dentry that is being created
562  * @extension: 9p2000.u extension string to support devices, etc.
563  * @perm: create permissions
564  * @mode: open mode
565  *
566  */
567 static struct p9_fid *
v9fs_create(struct v9fs_session_info * v9ses,struct inode * dir,struct dentry * dentry,char * extension,u32 perm,u8 mode)568 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
569 		struct dentry *dentry, char *extension, u32 perm, u8 mode)
570 {
571 	int err;
572 	const unsigned char *name;
573 	struct p9_fid *dfid, *ofid = NULL, *fid = NULL;
574 	struct inode *inode;
575 
576 	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
577 
578 	name = dentry->d_name.name;
579 	dfid = v9fs_parent_fid(dentry);
580 	if (IS_ERR(dfid)) {
581 		err = PTR_ERR(dfid);
582 		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
583 		return ERR_PTR(err);
584 	}
585 
586 	/* clone a fid to use for creation */
587 	ofid = clone_fid(dfid);
588 	if (IS_ERR(ofid)) {
589 		err = PTR_ERR(ofid);
590 		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
591 		goto error;
592 	}
593 
594 	err = p9_client_fcreate(ofid, name, perm, mode, extension);
595 	if (err < 0) {
596 		p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
597 		goto error;
598 	}
599 
600 	if (!(perm & P9_DMLINK)) {
601 		/* now walk from the parent so we can get unopened fid */
602 		fid = p9_client_walk(dfid, 1, &name, 1);
603 		if (IS_ERR(fid)) {
604 			err = PTR_ERR(fid);
605 			p9_debug(P9_DEBUG_VFS,
606 				   "p9_client_walk failed %d\n", err);
607 			goto error;
608 		}
609 		/*
610 		 * instantiate inode and assign the unopened fid to the dentry
611 		 */
612 		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
613 		if (IS_ERR(inode)) {
614 			err = PTR_ERR(inode);
615 			p9_debug(P9_DEBUG_VFS,
616 				   "inode creation failed %d\n", err);
617 			goto error;
618 		}
619 		v9fs_fid_add(dentry, &fid);
620 		d_instantiate(dentry, inode);
621 	}
622 	p9_fid_put(dfid);
623 	return ofid;
624 error:
625 	p9_fid_put(dfid);
626 	p9_fid_put(ofid);
627 	p9_fid_put(fid);
628 	return ERR_PTR(err);
629 }
630 
631 /**
632  * v9fs_vfs_create - VFS hook to create a regular file
633  * @idmap: idmap of the mount
634  * @dir: The parent directory
635  * @dentry: The name of file to be created
636  * @mode: The UNIX file mode to set
637  * @excl: True if the file must not yet exist
638  *
639  * open(.., O_CREAT) is handled in v9fs_vfs_atomic_open().  This is only called
640  * for mknod(2).
641  *
642  */
643 
644 static int
v9fs_vfs_create(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode,bool excl)645 v9fs_vfs_create(struct mnt_idmap *idmap, struct inode *dir,
646 		struct dentry *dentry, umode_t mode, bool excl)
647 {
648 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
649 	u32 perm = unixmode2p9mode(v9ses, mode);
650 	struct p9_fid *fid;
651 
652 	/* P9_OEXCL? */
653 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_ORDWR);
654 	if (IS_ERR(fid))
655 		return PTR_ERR(fid);
656 
657 	v9fs_invalidate_inode_attr(dir);
658 	p9_fid_put(fid);
659 
660 	return 0;
661 }
662 
663 /**
664  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
665  * @idmap: idmap of the mount
666  * @dir:  inode that is being unlinked
667  * @dentry: dentry that is being unlinked
668  * @mode: mode for new directory
669  *
670  */
671 
v9fs_vfs_mkdir(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode)672 static int v9fs_vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
673 			  struct dentry *dentry, umode_t mode)
674 {
675 	int err;
676 	u32 perm;
677 	struct p9_fid *fid;
678 	struct v9fs_session_info *v9ses;
679 
680 	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
681 	err = 0;
682 	v9ses = v9fs_inode2v9ses(dir);
683 	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
684 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
685 	if (IS_ERR(fid)) {
686 		err = PTR_ERR(fid);
687 		fid = NULL;
688 	} else {
689 		inc_nlink(dir);
690 		v9fs_invalidate_inode_attr(dir);
691 	}
692 
693 	if (fid)
694 		p9_fid_put(fid);
695 
696 	return err;
697 }
698 
699 /**
700  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
701  * @dir:  inode that is being walked from
702  * @dentry: dentry that is being walked to?
703  * @flags: lookup flags (unused)
704  *
705  */
706 
v9fs_vfs_lookup(struct inode * dir,struct dentry * dentry,unsigned int flags)707 struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
708 				      unsigned int flags)
709 {
710 	struct dentry *res;
711 	struct v9fs_session_info *v9ses;
712 	struct p9_fid *dfid, *fid;
713 	struct inode *inode;
714 	const unsigned char *name;
715 
716 	p9_debug(P9_DEBUG_VFS, "dir: %p dentry: (%pd) %p flags: %x\n",
717 		 dir, dentry, dentry, flags);
718 
719 	if (dentry->d_name.len > NAME_MAX)
720 		return ERR_PTR(-ENAMETOOLONG);
721 
722 	v9ses = v9fs_inode2v9ses(dir);
723 	/* We can walk d_parent because we hold the dir->i_mutex */
724 	dfid = v9fs_parent_fid(dentry);
725 	if (IS_ERR(dfid))
726 		return ERR_CAST(dfid);
727 
728 	/*
729 	 * Make sure we don't use a wrong inode due to parallel
730 	 * unlink. For cached mode create calls request for new
731 	 * inode. But with cache disabled, lookup should do this.
732 	 */
733 	name = dentry->d_name.name;
734 	fid = p9_client_walk(dfid, 1, &name, 1);
735 	p9_fid_put(dfid);
736 	if (fid == ERR_PTR(-ENOENT))
737 		inode = NULL;
738 	else if (IS_ERR(fid))
739 		inode = ERR_CAST(fid);
740 	else if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
741 		inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
742 	else
743 		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
744 	/*
745 	 * If we had a rename on the server and a parallel lookup
746 	 * for the new name, then make sure we instantiate with
747 	 * the new name. ie look up for a/b, while on server somebody
748 	 * moved b under k and client parallely did a lookup for
749 	 * k/b.
750 	 */
751 	res = d_splice_alias(inode, dentry);
752 	if (!IS_ERR(fid)) {
753 		if (!res)
754 			v9fs_fid_add(dentry, &fid);
755 		else if (!IS_ERR(res))
756 			v9fs_fid_add(res, &fid);
757 		else
758 			p9_fid_put(fid);
759 	}
760 	return res;
761 }
762 
763 static int
v9fs_vfs_atomic_open(struct inode * dir,struct dentry * dentry,struct file * file,unsigned int flags,umode_t mode)764 v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
765 		     struct file *file, unsigned int flags, umode_t mode)
766 {
767 	int err;
768 	u32 perm;
769 	struct v9fs_inode __maybe_unused *v9inode;
770 	struct v9fs_session_info *v9ses;
771 	struct p9_fid *fid;
772 	struct dentry *res = NULL;
773 	struct inode *inode;
774 	int p9_omode;
775 
776 	if (d_in_lookup(dentry)) {
777 		res = v9fs_vfs_lookup(dir, dentry, 0);
778 		if (IS_ERR(res))
779 			return PTR_ERR(res);
780 
781 		if (res)
782 			dentry = res;
783 	}
784 
785 	/* Only creates */
786 	if (!(flags & O_CREAT) || d_really_is_positive(dentry))
787 		return finish_no_open(file, res);
788 
789 	v9ses = v9fs_inode2v9ses(dir);
790 	perm = unixmode2p9mode(v9ses, mode);
791 	p9_omode = v9fs_uflags2omode(flags, v9fs_proto_dotu(v9ses));
792 
793 	if ((v9ses->cache & CACHE_WRITEBACK) && (p9_omode & P9_OWRITE)) {
794 		p9_omode = (p9_omode & ~P9_OWRITE) | P9_ORDWR;
795 		p9_debug(P9_DEBUG_CACHE,
796 			"write-only file with writeback enabled, creating w/ O_RDWR\n");
797 	}
798 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, p9_omode);
799 	if (IS_ERR(fid)) {
800 		err = PTR_ERR(fid);
801 		goto error;
802 	}
803 
804 	v9fs_invalidate_inode_attr(dir);
805 	inode = d_inode(dentry);
806 	v9inode = V9FS_I(inode);
807 	err = finish_open(file, dentry, generic_file_open);
808 	if (err)
809 		goto error;
810 
811 	file->private_data = fid;
812 #ifdef CONFIG_9P_FSCACHE
813 	if (v9ses->cache & CACHE_FSCACHE)
814 		fscache_use_cookie(v9fs_inode_cookie(v9inode),
815 				   file->f_mode & FMODE_WRITE);
816 #endif
817 
818 	v9fs_fid_add_modes(fid, v9ses->flags, v9ses->cache, file->f_flags);
819 	v9fs_open_fid_add(inode, &fid);
820 
821 	file->f_mode |= FMODE_CREATED;
822 out:
823 	dput(res);
824 	return err;
825 
826 error:
827 	p9_fid_put(fid);
828 	goto out;
829 }
830 
831 /**
832  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
833  * @i:  inode that is being unlinked
834  * @d: dentry that is being unlinked
835  *
836  */
837 
v9fs_vfs_unlink(struct inode * i,struct dentry * d)838 int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
839 {
840 	return v9fs_remove(i, d, 0);
841 }
842 
843 /**
844  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
845  * @i:  inode that is being unlinked
846  * @d: dentry that is being unlinked
847  *
848  */
849 
v9fs_vfs_rmdir(struct inode * i,struct dentry * d)850 int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
851 {
852 	return v9fs_remove(i, d, AT_REMOVEDIR);
853 }
854 
855 /**
856  * v9fs_vfs_rename - VFS hook to rename an inode
857  * @idmap: The idmap of the mount
858  * @old_dir:  old dir inode
859  * @old_dentry: old dentry
860  * @new_dir: new dir inode
861  * @new_dentry: new dentry
862  * @flags: RENAME_* flags
863  *
864  */
865 
866 int
v9fs_vfs_rename(struct mnt_idmap * idmap,struct inode * old_dir,struct dentry * old_dentry,struct inode * new_dir,struct dentry * new_dentry,unsigned int flags)867 v9fs_vfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
868 		struct dentry *old_dentry, struct inode *new_dir,
869 		struct dentry *new_dentry, unsigned int flags)
870 {
871 	int retval;
872 	struct inode *old_inode;
873 	struct inode *new_inode;
874 	struct v9fs_session_info *v9ses;
875 	struct p9_fid *oldfid = NULL, *dfid = NULL;
876 	struct p9_fid *olddirfid = NULL;
877 	struct p9_fid *newdirfid = NULL;
878 	struct p9_wstat wstat;
879 
880 	if (flags)
881 		return -EINVAL;
882 
883 	p9_debug(P9_DEBUG_VFS, "\n");
884 	old_inode = d_inode(old_dentry);
885 	new_inode = d_inode(new_dentry);
886 	v9ses = v9fs_inode2v9ses(old_inode);
887 	oldfid = v9fs_fid_lookup(old_dentry);
888 	if (IS_ERR(oldfid))
889 		return PTR_ERR(oldfid);
890 
891 	dfid = v9fs_parent_fid(old_dentry);
892 	olddirfid = clone_fid(dfid);
893 	p9_fid_put(dfid);
894 	dfid = NULL;
895 
896 	if (IS_ERR(olddirfid)) {
897 		retval = PTR_ERR(olddirfid);
898 		goto error;
899 	}
900 
901 	dfid = v9fs_parent_fid(new_dentry);
902 	newdirfid = clone_fid(dfid);
903 	p9_fid_put(dfid);
904 	dfid = NULL;
905 
906 	if (IS_ERR(newdirfid)) {
907 		retval = PTR_ERR(newdirfid);
908 		goto error;
909 	}
910 
911 	down_write(&v9ses->rename_sem);
912 	if (v9fs_proto_dotl(v9ses)) {
913 		retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
914 					    newdirfid, new_dentry->d_name.name);
915 		if (retval == -EOPNOTSUPP)
916 			retval = p9_client_rename(oldfid, newdirfid,
917 						  new_dentry->d_name.name);
918 		if (retval != -EOPNOTSUPP)
919 			goto error_locked;
920 	}
921 	if (old_dentry->d_parent != new_dentry->d_parent) {
922 		/*
923 		 * 9P .u can only handle file rename in the same directory
924 		 */
925 
926 		p9_debug(P9_DEBUG_ERROR, "old dir and new dir are different\n");
927 		retval = -EXDEV;
928 		goto error_locked;
929 	}
930 	v9fs_blank_wstat(&wstat);
931 	wstat.muid = v9ses->uname;
932 	wstat.name = new_dentry->d_name.name;
933 	retval = p9_client_wstat(oldfid, &wstat);
934 
935 error_locked:
936 	if (!retval) {
937 		if (new_inode) {
938 			if (S_ISDIR(new_inode->i_mode))
939 				clear_nlink(new_inode);
940 			else
941 				v9fs_dec_count(new_inode);
942 		}
943 		if (S_ISDIR(old_inode->i_mode)) {
944 			if (!new_inode)
945 				inc_nlink(new_dir);
946 			v9fs_dec_count(old_dir);
947 		}
948 		v9fs_invalidate_inode_attr(old_inode);
949 		v9fs_invalidate_inode_attr(old_dir);
950 		v9fs_invalidate_inode_attr(new_dir);
951 
952 		/* successful rename */
953 		d_move(old_dentry, new_dentry);
954 	}
955 	up_write(&v9ses->rename_sem);
956 
957 error:
958 	p9_fid_put(newdirfid);
959 	p9_fid_put(olddirfid);
960 	p9_fid_put(oldfid);
961 	return retval;
962 }
963 
964 /**
965  * v9fs_vfs_getattr - retrieve file metadata
966  * @idmap: idmap of the mount
967  * @path: Object to query
968  * @stat: metadata structure to populate
969  * @request_mask: Mask of STATX_xxx flags indicating the caller's interests
970  * @flags: AT_STATX_xxx setting
971  *
972  */
973 
974 static int
v9fs_vfs_getattr(struct mnt_idmap * idmap,const struct path * path,struct kstat * stat,u32 request_mask,unsigned int flags)975 v9fs_vfs_getattr(struct mnt_idmap *idmap, const struct path *path,
976 		 struct kstat *stat, u32 request_mask, unsigned int flags)
977 {
978 	struct dentry *dentry = path->dentry;
979 	struct inode *inode = d_inode(dentry);
980 	struct v9fs_session_info *v9ses;
981 	struct p9_fid *fid;
982 	struct p9_wstat *st;
983 
984 	p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
985 	v9ses = v9fs_dentry2v9ses(dentry);
986 	if (v9ses->cache & (CACHE_META|CACHE_LOOSE)) {
987 		generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
988 		return 0;
989 	} else if (v9ses->cache & CACHE_WRITEBACK) {
990 		if (S_ISREG(inode->i_mode)) {
991 			int retval = filemap_fdatawrite(inode->i_mapping);
992 
993 			if (retval)
994 				p9_debug(P9_DEBUG_ERROR,
995 				    "flushing writeback during getattr returned %d\n", retval);
996 		}
997 	}
998 	fid = v9fs_fid_lookup(dentry);
999 	if (IS_ERR(fid))
1000 		return PTR_ERR(fid);
1001 
1002 	st = p9_client_stat(fid);
1003 	p9_fid_put(fid);
1004 	if (IS_ERR(st))
1005 		return PTR_ERR(st);
1006 
1007 	v9fs_stat2inode(st, d_inode(dentry), dentry->d_sb, 0);
1008 	generic_fillattr(&nop_mnt_idmap, request_mask, d_inode(dentry), stat);
1009 
1010 	p9stat_free(st);
1011 	kfree(st);
1012 	return 0;
1013 }
1014 
1015 /**
1016  * v9fs_vfs_setattr - set file metadata
1017  * @idmap: idmap of the mount
1018  * @dentry: file whose metadata to set
1019  * @iattr: metadata assignment structure
1020  *
1021  */
1022 
v9fs_vfs_setattr(struct mnt_idmap * idmap,struct dentry * dentry,struct iattr * iattr)1023 static int v9fs_vfs_setattr(struct mnt_idmap *idmap,
1024 			    struct dentry *dentry, struct iattr *iattr)
1025 {
1026 	int retval, use_dentry = 0;
1027 	struct inode *inode = d_inode(dentry);
1028 	struct v9fs_session_info *v9ses;
1029 	struct p9_fid *fid = NULL;
1030 	struct p9_wstat wstat;
1031 
1032 	p9_debug(P9_DEBUG_VFS, "\n");
1033 	retval = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
1034 	if (retval)
1035 		return retval;
1036 
1037 	v9ses = v9fs_dentry2v9ses(dentry);
1038 	if (iattr->ia_valid & ATTR_FILE) {
1039 		fid = iattr->ia_file->private_data;
1040 		WARN_ON(!fid);
1041 	}
1042 	if (!fid) {
1043 		fid = v9fs_fid_lookup(dentry);
1044 		use_dentry = 1;
1045 	}
1046 	if (IS_ERR(fid))
1047 		return PTR_ERR(fid);
1048 
1049 	v9fs_blank_wstat(&wstat);
1050 	if (iattr->ia_valid & ATTR_MODE)
1051 		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
1052 
1053 	if (iattr->ia_valid & ATTR_MTIME)
1054 		wstat.mtime = iattr->ia_mtime.tv_sec;
1055 
1056 	if (iattr->ia_valid & ATTR_ATIME)
1057 		wstat.atime = iattr->ia_atime.tv_sec;
1058 
1059 	if (iattr->ia_valid & ATTR_SIZE)
1060 		wstat.length = iattr->ia_size;
1061 
1062 	if (v9fs_proto_dotu(v9ses)) {
1063 		if (iattr->ia_valid & ATTR_UID)
1064 			wstat.n_uid = iattr->ia_uid;
1065 
1066 		if (iattr->ia_valid & ATTR_GID)
1067 			wstat.n_gid = iattr->ia_gid;
1068 	}
1069 
1070 	/* Write all dirty data */
1071 	if (d_is_reg(dentry)) {
1072 		retval = filemap_fdatawrite(inode->i_mapping);
1073 		if (retval)
1074 			p9_debug(P9_DEBUG_ERROR,
1075 			    "flushing writeback during setattr returned %d\n", retval);
1076 	}
1077 
1078 	retval = p9_client_wstat(fid, &wstat);
1079 
1080 	if (use_dentry)
1081 		p9_fid_put(fid);
1082 
1083 	if (retval < 0)
1084 		return retval;
1085 
1086 	if ((iattr->ia_valid & ATTR_SIZE) &&
1087 		 iattr->ia_size != i_size_read(inode)) {
1088 		truncate_setsize(inode, iattr->ia_size);
1089 		netfs_resize_file(netfs_inode(inode), iattr->ia_size, true);
1090 
1091 #ifdef CONFIG_9P_FSCACHE
1092 		if (v9ses->cache & CACHE_FSCACHE) {
1093 			struct v9fs_inode *v9inode = V9FS_I(inode);
1094 
1095 			fscache_resize_cookie(v9fs_inode_cookie(v9inode), iattr->ia_size);
1096 		}
1097 #endif
1098 	}
1099 
1100 	v9fs_invalidate_inode_attr(inode);
1101 
1102 	setattr_copy(&nop_mnt_idmap, inode, iattr);
1103 	mark_inode_dirty(inode);
1104 	return 0;
1105 }
1106 
1107 /**
1108  * v9fs_stat2inode - populate an inode structure with mistat info
1109  * @stat: Plan 9 metadata (mistat) structure
1110  * @inode: inode to populate
1111  * @sb: superblock of filesystem
1112  * @flags: control flags (e.g. V9FS_STAT2INODE_KEEP_ISIZE)
1113  *
1114  */
1115 
1116 void
v9fs_stat2inode(struct p9_wstat * stat,struct inode * inode,struct super_block * sb,unsigned int flags)1117 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
1118 		 struct super_block *sb, unsigned int flags)
1119 {
1120 	umode_t mode;
1121 	struct v9fs_session_info *v9ses = sb->s_fs_info;
1122 	struct v9fs_inode *v9inode = V9FS_I(inode);
1123 
1124 	inode_set_atime(inode, stat->atime, 0);
1125 	inode_set_mtime(inode, stat->mtime, 0);
1126 	inode_set_ctime(inode, stat->mtime, 0);
1127 
1128 	inode->i_uid = v9ses->dfltuid;
1129 	inode->i_gid = v9ses->dfltgid;
1130 
1131 	if (v9fs_proto_dotu(v9ses)) {
1132 		inode->i_uid = stat->n_uid;
1133 		inode->i_gid = stat->n_gid;
1134 	}
1135 	if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
1136 		if (v9fs_proto_dotu(v9ses)) {
1137 			unsigned int i_nlink;
1138 			/*
1139 			 * Hadlink support got added later to the .u extension.
1140 			 * So there can be a server out there that doesn't
1141 			 * support this even with .u extension. That would
1142 			 * just leave us with stat->extension being an empty
1143 			 * string, though.
1144 			 */
1145 			/* HARDLINKCOUNT %u */
1146 			if (sscanf(stat->extension,
1147 				   " HARDLINKCOUNT %u", &i_nlink) == 1)
1148 				set_nlink(inode, i_nlink);
1149 		}
1150 	}
1151 	mode = p9mode2perm(v9ses, stat);
1152 	mode |= inode->i_mode & ~S_IALLUGO;
1153 	inode->i_mode = mode;
1154 
1155 	v9inode->netfs.remote_i_size = stat->length;
1156 	if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
1157 		v9fs_i_size_write(inode, stat->length);
1158 	/* not real number of blocks, but 512 byte ones ... */
1159 	inode->i_blocks = (stat->length + 512 - 1) >> 9;
1160 	v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
1161 }
1162 
1163 /**
1164  * v9fs_vfs_get_link - follow a symlink path
1165  * @dentry: dentry for symlink
1166  * @inode: inode for symlink
1167  * @done: delayed call for when we are done with the return value
1168  */
1169 
v9fs_vfs_get_link(struct dentry * dentry,struct inode * inode,struct delayed_call * done)1170 static const char *v9fs_vfs_get_link(struct dentry *dentry,
1171 				     struct inode *inode,
1172 				     struct delayed_call *done)
1173 {
1174 	struct v9fs_session_info *v9ses;
1175 	struct p9_fid *fid;
1176 	struct p9_wstat *st;
1177 	char *res;
1178 
1179 	if (!dentry)
1180 		return ERR_PTR(-ECHILD);
1181 
1182 	v9ses = v9fs_dentry2v9ses(dentry);
1183 	if (!v9fs_proto_dotu(v9ses))
1184 		return ERR_PTR(-EBADF);
1185 
1186 	p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
1187 	fid = v9fs_fid_lookup(dentry);
1188 
1189 	if (IS_ERR(fid))
1190 		return ERR_CAST(fid);
1191 
1192 	st = p9_client_stat(fid);
1193 	p9_fid_put(fid);
1194 	if (IS_ERR(st))
1195 		return ERR_CAST(st);
1196 
1197 	if (!(st->mode & P9_DMSYMLINK)) {
1198 		p9stat_free(st);
1199 		kfree(st);
1200 		return ERR_PTR(-EINVAL);
1201 	}
1202 	res = st->extension;
1203 	st->extension = NULL;
1204 	if (strlen(res) >= PATH_MAX)
1205 		res[PATH_MAX - 1] = '\0';
1206 
1207 	p9stat_free(st);
1208 	kfree(st);
1209 	set_delayed_call(done, kfree_link, res);
1210 	return res;
1211 }
1212 
1213 /**
1214  * v9fs_vfs_mkspecial - create a special file
1215  * @dir: inode to create special file in
1216  * @dentry: dentry to create
1217  * @perm: mode to create special file
1218  * @extension: 9p2000.u format extension string representing special file
1219  *
1220  */
1221 
v9fs_vfs_mkspecial(struct inode * dir,struct dentry * dentry,u32 perm,const char * extension)1222 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1223 	u32 perm, const char *extension)
1224 {
1225 	struct p9_fid *fid;
1226 	struct v9fs_session_info *v9ses;
1227 
1228 	v9ses = v9fs_inode2v9ses(dir);
1229 	if (!v9fs_proto_dotu(v9ses)) {
1230 		p9_debug(P9_DEBUG_ERROR, "not extended\n");
1231 		return -EPERM;
1232 	}
1233 
1234 	fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1235 								P9_OREAD);
1236 	if (IS_ERR(fid))
1237 		return PTR_ERR(fid);
1238 
1239 	v9fs_invalidate_inode_attr(dir);
1240 	p9_fid_put(fid);
1241 	return 0;
1242 }
1243 
1244 /**
1245  * v9fs_vfs_symlink - helper function to create symlinks
1246  * @idmap: idmap of the mount
1247  * @dir: directory inode containing symlink
1248  * @dentry: dentry for symlink
1249  * @symname: symlink data
1250  *
1251  * See Also: 9P2000.u RFC for more information
1252  *
1253  */
1254 
1255 static int
v9fs_vfs_symlink(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,const char * symname)1256 v9fs_vfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
1257 		 struct dentry *dentry, const char *symname)
1258 {
1259 	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%s\n",
1260 		 dir->i_ino, dentry, symname);
1261 
1262 	return v9fs_vfs_mkspecial(dir, dentry, P9_DMSYMLINK, symname);
1263 }
1264 
1265 #define U32_MAX_DIGITS 10
1266 
1267 /**
1268  * v9fs_vfs_link - create a hardlink
1269  * @old_dentry: dentry for file to link to
1270  * @dir: inode destination for new link
1271  * @dentry: dentry for link
1272  *
1273  */
1274 
1275 static int
v9fs_vfs_link(struct dentry * old_dentry,struct inode * dir,struct dentry * dentry)1276 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1277 	      struct dentry *dentry)
1278 {
1279 	int retval;
1280 	char name[1 + U32_MAX_DIGITS + 2]; /* sign + number + \n + \0 */
1281 	struct p9_fid *oldfid;
1282 
1283 	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%pd\n",
1284 		 dir->i_ino, dentry, old_dentry);
1285 
1286 	oldfid = v9fs_fid_clone(old_dentry);
1287 	if (IS_ERR(oldfid))
1288 		return PTR_ERR(oldfid);
1289 
1290 	sprintf(name, "%d\n", oldfid->fid);
1291 	retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1292 	if (!retval) {
1293 		v9fs_refresh_inode(oldfid, d_inode(old_dentry));
1294 		v9fs_invalidate_inode_attr(dir);
1295 	}
1296 	p9_fid_put(oldfid);
1297 	return retval;
1298 }
1299 
1300 /**
1301  * v9fs_vfs_mknod - create a special file
1302  * @idmap: idmap of the mount
1303  * @dir: inode destination for new link
1304  * @dentry: dentry for file
1305  * @mode: mode for creation
1306  * @rdev: device associated with special file
1307  *
1308  */
1309 
1310 static int
v9fs_vfs_mknod(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode,dev_t rdev)1311 v9fs_vfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
1312 	       struct dentry *dentry, umode_t mode, dev_t rdev)
1313 {
1314 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
1315 	int retval;
1316 	char name[2 + U32_MAX_DIGITS + 1 + U32_MAX_DIGITS + 1];
1317 	u32 perm;
1318 
1319 	p9_debug(P9_DEBUG_VFS, " %lu,%pd mode: %x MAJOR: %u MINOR: %u\n",
1320 		 dir->i_ino, dentry, mode,
1321 		 MAJOR(rdev), MINOR(rdev));
1322 
1323 	/* build extension */
1324 	if (S_ISBLK(mode))
1325 		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1326 	else if (S_ISCHR(mode))
1327 		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1328 	else
1329 		*name = 0;
1330 
1331 	perm = unixmode2p9mode(v9ses, mode);
1332 	retval = v9fs_vfs_mkspecial(dir, dentry, perm, name);
1333 
1334 	return retval;
1335 }
1336 
v9fs_refresh_inode(struct p9_fid * fid,struct inode * inode)1337 int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
1338 {
1339 	int umode;
1340 	dev_t rdev;
1341 	struct p9_wstat *st;
1342 	struct v9fs_session_info *v9ses;
1343 	unsigned int flags;
1344 
1345 	v9ses = v9fs_inode2v9ses(inode);
1346 	st = p9_client_stat(fid);
1347 	if (IS_ERR(st))
1348 		return PTR_ERR(st);
1349 	/*
1350 	 * Don't update inode if the file type is different
1351 	 */
1352 	umode = p9mode2unixmode(v9ses, st, &rdev);
1353 	if (inode_wrong_type(inode, umode))
1354 		goto out;
1355 
1356 	/*
1357 	 * We don't want to refresh inode->i_size,
1358 	 * because we may have cached data
1359 	 */
1360 	flags = (v9ses->cache & CACHE_LOOSE) ?
1361 		V9FS_STAT2INODE_KEEP_ISIZE : 0;
1362 	v9fs_stat2inode(st, inode, inode->i_sb, flags);
1363 out:
1364 	p9stat_free(st);
1365 	kfree(st);
1366 	return 0;
1367 }
1368 
1369 static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1370 	.create = v9fs_vfs_create,
1371 	.lookup = v9fs_vfs_lookup,
1372 	.atomic_open = v9fs_vfs_atomic_open,
1373 	.symlink = v9fs_vfs_symlink,
1374 	.link = v9fs_vfs_link,
1375 	.unlink = v9fs_vfs_unlink,
1376 	.mkdir = v9fs_vfs_mkdir,
1377 	.rmdir = v9fs_vfs_rmdir,
1378 	.mknod = v9fs_vfs_mknod,
1379 	.rename = v9fs_vfs_rename,
1380 	.getattr = v9fs_vfs_getattr,
1381 	.setattr = v9fs_vfs_setattr,
1382 };
1383 
1384 static const struct inode_operations v9fs_dir_inode_operations = {
1385 	.create = v9fs_vfs_create,
1386 	.lookup = v9fs_vfs_lookup,
1387 	.atomic_open = v9fs_vfs_atomic_open,
1388 	.unlink = v9fs_vfs_unlink,
1389 	.mkdir = v9fs_vfs_mkdir,
1390 	.rmdir = v9fs_vfs_rmdir,
1391 	.mknod = v9fs_vfs_mknod,
1392 	.rename = v9fs_vfs_rename,
1393 	.getattr = v9fs_vfs_getattr,
1394 	.setattr = v9fs_vfs_setattr,
1395 };
1396 
1397 static const struct inode_operations v9fs_file_inode_operations = {
1398 	.getattr = v9fs_vfs_getattr,
1399 	.setattr = v9fs_vfs_setattr,
1400 };
1401 
1402 static const struct inode_operations v9fs_symlink_inode_operations = {
1403 	.get_link = v9fs_vfs_get_link,
1404 	.getattr = v9fs_vfs_getattr,
1405 	.setattr = v9fs_vfs_setattr,
1406 };
1407 
1408