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