1 /* dir.c: AFS filesystem directory handling
2  *
3  * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11 
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/fs.h>
16 #include <linux/namei.h>
17 #include <linux/pagemap.h>
18 #include <linux/ctype.h>
19 #include <linux/sched.h>
20 #include "internal.h"
21 
22 static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
23 				 struct nameidata *nd);
24 static int afs_dir_open(struct inode *inode, struct file *file);
25 static int afs_readdir(struct file *file, void *dirent, filldir_t filldir);
26 static int afs_d_revalidate(struct dentry *dentry, struct nameidata *nd);
27 static int afs_d_delete(const struct dentry *dentry);
28 static void afs_d_release(struct dentry *dentry);
29 static int afs_lookup_filldir(void *_cookie, const char *name, int nlen,
30 				  loff_t fpos, u64 ino, unsigned dtype);
31 static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
32 		      struct nameidata *nd);
33 static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode);
34 static int afs_rmdir(struct inode *dir, struct dentry *dentry);
35 static int afs_unlink(struct inode *dir, struct dentry *dentry);
36 static int afs_link(struct dentry *from, struct inode *dir,
37 		    struct dentry *dentry);
38 static int afs_symlink(struct inode *dir, struct dentry *dentry,
39 		       const char *content);
40 static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
41 		      struct inode *new_dir, struct dentry *new_dentry);
42 
43 const struct file_operations afs_dir_file_operations = {
44 	.open		= afs_dir_open,
45 	.release	= afs_release,
46 	.readdir	= afs_readdir,
47 	.lock		= afs_lock,
48 	.llseek		= generic_file_llseek,
49 };
50 
51 const struct inode_operations afs_dir_inode_operations = {
52 	.create		= afs_create,
53 	.lookup		= afs_lookup,
54 	.link		= afs_link,
55 	.unlink		= afs_unlink,
56 	.symlink	= afs_symlink,
57 	.mkdir		= afs_mkdir,
58 	.rmdir		= afs_rmdir,
59 	.rename		= afs_rename,
60 	.permission	= afs_permission,
61 	.getattr	= afs_getattr,
62 	.setattr	= afs_setattr,
63 };
64 
65 const struct dentry_operations afs_fs_dentry_operations = {
66 	.d_revalidate	= afs_d_revalidate,
67 	.d_delete	= afs_d_delete,
68 	.d_release	= afs_d_release,
69 	.d_automount	= afs_d_automount,
70 };
71 
72 #define AFS_DIR_HASHTBL_SIZE	128
73 #define AFS_DIR_DIRENT_SIZE	32
74 #define AFS_DIRENT_PER_BLOCK	64
75 
76 union afs_dirent {
77 	struct {
78 		uint8_t		valid;
79 		uint8_t		unused[1];
80 		__be16		hash_next;
81 		__be32		vnode;
82 		__be32		unique;
83 		uint8_t		name[16];
84 		uint8_t		overflow[4];	/* if any char of the name (inc
85 						 * NUL) reaches here, consume
86 						 * the next dirent too */
87 	} u;
88 	uint8_t	extended_name[32];
89 };
90 
91 /* AFS directory page header (one at the beginning of every 2048-byte chunk) */
92 struct afs_dir_pagehdr {
93 	__be16		npages;
94 	__be16		magic;
95 #define AFS_DIR_MAGIC htons(1234)
96 	uint8_t		nentries;
97 	uint8_t		bitmap[8];
98 	uint8_t		pad[19];
99 };
100 
101 /* directory block layout */
102 union afs_dir_block {
103 
104 	struct afs_dir_pagehdr pagehdr;
105 
106 	struct {
107 		struct afs_dir_pagehdr	pagehdr;
108 		uint8_t			alloc_ctrs[128];
109 		/* dir hash table */
110 		uint16_t		hashtable[AFS_DIR_HASHTBL_SIZE];
111 	} hdr;
112 
113 	union afs_dirent dirents[AFS_DIRENT_PER_BLOCK];
114 };
115 
116 /* layout on a linux VM page */
117 struct afs_dir_page {
118 	union afs_dir_block blocks[PAGE_SIZE / sizeof(union afs_dir_block)];
119 };
120 
121 struct afs_lookup_cookie {
122 	struct afs_fid	fid;
123 	const char	*name;
124 	size_t		nlen;
125 	int		found;
126 };
127 
128 /*
129  * check that a directory page is valid
130  */
afs_dir_check_page(struct inode * dir,struct page * page)131 static inline void afs_dir_check_page(struct inode *dir, struct page *page)
132 {
133 	struct afs_dir_page *dbuf;
134 	loff_t latter;
135 	int tmp, qty;
136 
137 #if 0
138 	/* check the page count */
139 	qty = desc.size / sizeof(dbuf->blocks[0]);
140 	if (qty == 0)
141 		goto error;
142 
143 	if (page->index == 0 && qty != ntohs(dbuf->blocks[0].pagehdr.npages)) {
144 		printk("kAFS: %s(%lu): wrong number of dir blocks %d!=%hu\n",
145 		       __func__, dir->i_ino, qty,
146 		       ntohs(dbuf->blocks[0].pagehdr.npages));
147 		goto error;
148 	}
149 #endif
150 
151 	/* determine how many magic numbers there should be in this page */
152 	latter = dir->i_size - page_offset(page);
153 	if (latter >= PAGE_SIZE)
154 		qty = PAGE_SIZE;
155 	else
156 		qty = latter;
157 	qty /= sizeof(union afs_dir_block);
158 
159 	/* check them */
160 	dbuf = page_address(page);
161 	for (tmp = 0; tmp < qty; tmp++) {
162 		if (dbuf->blocks[tmp].pagehdr.magic != AFS_DIR_MAGIC) {
163 			printk("kAFS: %s(%lu): bad magic %d/%d is %04hx\n",
164 			       __func__, dir->i_ino, tmp, qty,
165 			       ntohs(dbuf->blocks[tmp].pagehdr.magic));
166 			goto error;
167 		}
168 	}
169 
170 	SetPageChecked(page);
171 	return;
172 
173 error:
174 	SetPageChecked(page);
175 	SetPageError(page);
176 }
177 
178 /*
179  * discard a page cached in the pagecache
180  */
afs_dir_put_page(struct page * page)181 static inline void afs_dir_put_page(struct page *page)
182 {
183 	kunmap(page);
184 	page_cache_release(page);
185 }
186 
187 /*
188  * get a page into the pagecache
189  */
afs_dir_get_page(struct inode * dir,unsigned long index,struct key * key)190 static struct page *afs_dir_get_page(struct inode *dir, unsigned long index,
191 				     struct key *key)
192 {
193 	struct page *page;
194 	_enter("{%lu},%lu", dir->i_ino, index);
195 
196 	page = read_cache_page(dir->i_mapping, index, afs_page_filler, key);
197 	if (!IS_ERR(page)) {
198 		kmap(page);
199 		if (!PageChecked(page))
200 			afs_dir_check_page(dir, page);
201 		if (PageError(page))
202 			goto fail;
203 	}
204 	return page;
205 
206 fail:
207 	afs_dir_put_page(page);
208 	_leave(" = -EIO");
209 	return ERR_PTR(-EIO);
210 }
211 
212 /*
213  * open an AFS directory file
214  */
afs_dir_open(struct inode * inode,struct file * file)215 static int afs_dir_open(struct inode *inode, struct file *file)
216 {
217 	_enter("{%lu}", inode->i_ino);
218 
219 	BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);
220 	BUILD_BUG_ON(sizeof(union afs_dirent) != 32);
221 
222 	if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(inode)->flags))
223 		return -ENOENT;
224 
225 	return afs_open(inode, file);
226 }
227 
228 /*
229  * deal with one block in an AFS directory
230  */
afs_dir_iterate_block(unsigned * fpos,union afs_dir_block * block,unsigned blkoff,void * cookie,filldir_t filldir)231 static int afs_dir_iterate_block(unsigned *fpos,
232 				 union afs_dir_block *block,
233 				 unsigned blkoff,
234 				 void *cookie,
235 				 filldir_t filldir)
236 {
237 	union afs_dirent *dire;
238 	unsigned offset, next, curr;
239 	size_t nlen;
240 	int tmp, ret;
241 
242 	_enter("%u,%x,%p,,",*fpos,blkoff,block);
243 
244 	curr = (*fpos - blkoff) / sizeof(union afs_dirent);
245 
246 	/* walk through the block, an entry at a time */
247 	for (offset = AFS_DIRENT_PER_BLOCK - block->pagehdr.nentries;
248 	     offset < AFS_DIRENT_PER_BLOCK;
249 	     offset = next
250 	     ) {
251 		next = offset + 1;
252 
253 		/* skip entries marked unused in the bitmap */
254 		if (!(block->pagehdr.bitmap[offset / 8] &
255 		      (1 << (offset % 8)))) {
256 			_debug("ENT[%Zu.%u]: unused",
257 			       blkoff / sizeof(union afs_dir_block), offset);
258 			if (offset >= curr)
259 				*fpos = blkoff +
260 					next * sizeof(union afs_dirent);
261 			continue;
262 		}
263 
264 		/* got a valid entry */
265 		dire = &block->dirents[offset];
266 		nlen = strnlen(dire->u.name,
267 			       sizeof(*block) -
268 			       offset * sizeof(union afs_dirent));
269 
270 		_debug("ENT[%Zu.%u]: %s %Zu \"%s\"",
271 		       blkoff / sizeof(union afs_dir_block), offset,
272 		       (offset < curr ? "skip" : "fill"),
273 		       nlen, dire->u.name);
274 
275 		/* work out where the next possible entry is */
276 		for (tmp = nlen; tmp > 15; tmp -= sizeof(union afs_dirent)) {
277 			if (next >= AFS_DIRENT_PER_BLOCK) {
278 				_debug("ENT[%Zu.%u]:"
279 				       " %u travelled beyond end dir block"
280 				       " (len %u/%Zu)",
281 				       blkoff / sizeof(union afs_dir_block),
282 				       offset, next, tmp, nlen);
283 				return -EIO;
284 			}
285 			if (!(block->pagehdr.bitmap[next / 8] &
286 			      (1 << (next % 8)))) {
287 				_debug("ENT[%Zu.%u]:"
288 				       " %u unmarked extension (len %u/%Zu)",
289 				       blkoff / sizeof(union afs_dir_block),
290 				       offset, next, tmp, nlen);
291 				return -EIO;
292 			}
293 
294 			_debug("ENT[%Zu.%u]: ext %u/%Zu",
295 			       blkoff / sizeof(union afs_dir_block),
296 			       next, tmp, nlen);
297 			next++;
298 		}
299 
300 		/* skip if starts before the current position */
301 		if (offset < curr)
302 			continue;
303 
304 		/* found the next entry */
305 		ret = filldir(cookie,
306 			      dire->u.name,
307 			      nlen,
308 			      blkoff + offset * sizeof(union afs_dirent),
309 			      ntohl(dire->u.vnode),
310 			      filldir == afs_lookup_filldir ?
311 			      ntohl(dire->u.unique) : DT_UNKNOWN);
312 		if (ret < 0) {
313 			_leave(" = 0 [full]");
314 			return 0;
315 		}
316 
317 		*fpos = blkoff + next * sizeof(union afs_dirent);
318 	}
319 
320 	_leave(" = 1 [more]");
321 	return 1;
322 }
323 
324 /*
325  * iterate through the data blob that lists the contents of an AFS directory
326  */
afs_dir_iterate(struct inode * dir,unsigned * fpos,void * cookie,filldir_t filldir,struct key * key)327 static int afs_dir_iterate(struct inode *dir, unsigned *fpos, void *cookie,
328 			   filldir_t filldir, struct key *key)
329 {
330 	union afs_dir_block *dblock;
331 	struct afs_dir_page *dbuf;
332 	struct page *page;
333 	unsigned blkoff, limit;
334 	int ret;
335 
336 	_enter("{%lu},%u,,", dir->i_ino, *fpos);
337 
338 	if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(dir)->flags)) {
339 		_leave(" = -ESTALE");
340 		return -ESTALE;
341 	}
342 
343 	/* round the file position up to the next entry boundary */
344 	*fpos += sizeof(union afs_dirent) - 1;
345 	*fpos &= ~(sizeof(union afs_dirent) - 1);
346 
347 	/* walk through the blocks in sequence */
348 	ret = 0;
349 	while (*fpos < dir->i_size) {
350 		blkoff = *fpos & ~(sizeof(union afs_dir_block) - 1);
351 
352 		/* fetch the appropriate page from the directory */
353 		page = afs_dir_get_page(dir, blkoff / PAGE_SIZE, key);
354 		if (IS_ERR(page)) {
355 			ret = PTR_ERR(page);
356 			break;
357 		}
358 
359 		limit = blkoff & ~(PAGE_SIZE - 1);
360 
361 		dbuf = page_address(page);
362 
363 		/* deal with the individual blocks stashed on this page */
364 		do {
365 			dblock = &dbuf->blocks[(blkoff % PAGE_SIZE) /
366 					       sizeof(union afs_dir_block)];
367 			ret = afs_dir_iterate_block(fpos, dblock, blkoff,
368 						    cookie, filldir);
369 			if (ret != 1) {
370 				afs_dir_put_page(page);
371 				goto out;
372 			}
373 
374 			blkoff += sizeof(union afs_dir_block);
375 
376 		} while (*fpos < dir->i_size && blkoff < limit);
377 
378 		afs_dir_put_page(page);
379 		ret = 0;
380 	}
381 
382 out:
383 	_leave(" = %d", ret);
384 	return ret;
385 }
386 
387 /*
388  * read an AFS directory
389  */
afs_readdir(struct file * file,void * cookie,filldir_t filldir)390 static int afs_readdir(struct file *file, void *cookie, filldir_t filldir)
391 {
392 	unsigned fpos;
393 	int ret;
394 
395 	_enter("{%Ld,{%lu}}",
396 	       file->f_pos, file->f_path.dentry->d_inode->i_ino);
397 
398 	ASSERT(file->private_data != NULL);
399 
400 	fpos = file->f_pos;
401 	ret = afs_dir_iterate(file->f_path.dentry->d_inode, &fpos,
402 			      cookie, filldir, file->private_data);
403 	file->f_pos = fpos;
404 
405 	_leave(" = %d", ret);
406 	return ret;
407 }
408 
409 /*
410  * search the directory for a name
411  * - if afs_dir_iterate_block() spots this function, it'll pass the FID
412  *   uniquifier through dtype
413  */
afs_lookup_filldir(void * _cookie,const char * name,int nlen,loff_t fpos,u64 ino,unsigned dtype)414 static int afs_lookup_filldir(void *_cookie, const char *name, int nlen,
415 			      loff_t fpos, u64 ino, unsigned dtype)
416 {
417 	struct afs_lookup_cookie *cookie = _cookie;
418 
419 	_enter("{%s,%Zu},%s,%u,,%llu,%u",
420 	       cookie->name, cookie->nlen, name, nlen,
421 	       (unsigned long long) ino, dtype);
422 
423 	/* insanity checks first */
424 	BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);
425 	BUILD_BUG_ON(sizeof(union afs_dirent) != 32);
426 
427 	if (cookie->nlen != nlen || memcmp(cookie->name, name, nlen) != 0) {
428 		_leave(" = 0 [no]");
429 		return 0;
430 	}
431 
432 	cookie->fid.vnode = ino;
433 	cookie->fid.unique = dtype;
434 	cookie->found = 1;
435 
436 	_leave(" = -1 [found]");
437 	return -1;
438 }
439 
440 /*
441  * do a lookup in a directory
442  * - just returns the FID the dentry name maps to if found
443  */
afs_do_lookup(struct inode * dir,struct dentry * dentry,struct afs_fid * fid,struct key * key)444 static int afs_do_lookup(struct inode *dir, struct dentry *dentry,
445 			 struct afs_fid *fid, struct key *key)
446 {
447 	struct afs_lookup_cookie cookie;
448 	struct afs_super_info *as;
449 	unsigned fpos;
450 	int ret;
451 
452 	_enter("{%lu},%p{%s},", dir->i_ino, dentry, dentry->d_name.name);
453 
454 	as = dir->i_sb->s_fs_info;
455 
456 	/* search the directory */
457 	cookie.name	= dentry->d_name.name;
458 	cookie.nlen	= dentry->d_name.len;
459 	cookie.fid.vid	= as->volume->vid;
460 	cookie.found	= 0;
461 
462 	fpos = 0;
463 	ret = afs_dir_iterate(dir, &fpos, &cookie, afs_lookup_filldir,
464 			      key);
465 	if (ret < 0) {
466 		_leave(" = %d [iter]", ret);
467 		return ret;
468 	}
469 
470 	ret = -ENOENT;
471 	if (!cookie.found) {
472 		_leave(" = -ENOENT [not found]");
473 		return -ENOENT;
474 	}
475 
476 	*fid = cookie.fid;
477 	_leave(" = 0 { vn=%u u=%u }", fid->vnode, fid->unique);
478 	return 0;
479 }
480 
481 /*
482  * Try to auto mount the mountpoint with pseudo directory, if the autocell
483  * operation is setted.
484  */
afs_try_auto_mntpt(int ret,struct dentry * dentry,struct inode * dir,struct key * key,struct afs_fid * fid)485 static struct inode *afs_try_auto_mntpt(
486 	int ret, struct dentry *dentry, struct inode *dir, struct key *key,
487 	struct afs_fid *fid)
488 {
489 	const char *devname = dentry->d_name.name;
490 	struct afs_vnode *vnode = AFS_FS_I(dir);
491 	struct inode *inode;
492 
493 	_enter("%d, %p{%s}, {%x:%u}, %p",
494 	       ret, dentry, devname, vnode->fid.vid, vnode->fid.vnode, key);
495 
496 	if (ret != -ENOENT ||
497 	    !test_bit(AFS_VNODE_AUTOCELL, &vnode->flags))
498 		goto out;
499 
500 	inode = afs_iget_autocell(dir, devname, strlen(devname), key);
501 	if (IS_ERR(inode)) {
502 		ret = PTR_ERR(inode);
503 		goto out;
504 	}
505 
506 	*fid = AFS_FS_I(inode)->fid;
507 	_leave("= %p", inode);
508 	return inode;
509 
510 out:
511 	_leave("= %d", ret);
512 	return ERR_PTR(ret);
513 }
514 
515 /*
516  * look up an entry in a directory
517  */
afs_lookup(struct inode * dir,struct dentry * dentry,struct nameidata * nd)518 static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
519 				 struct nameidata *nd)
520 {
521 	struct afs_vnode *vnode;
522 	struct afs_fid fid;
523 	struct inode *inode;
524 	struct key *key;
525 	int ret;
526 
527 	vnode = AFS_FS_I(dir);
528 
529 	_enter("{%x:%u},%p{%s},",
530 	       vnode->fid.vid, vnode->fid.vnode, dentry, dentry->d_name.name);
531 
532 	ASSERTCMP(dentry->d_inode, ==, NULL);
533 
534 	if (dentry->d_name.len >= AFSNAMEMAX) {
535 		_leave(" = -ENAMETOOLONG");
536 		return ERR_PTR(-ENAMETOOLONG);
537 	}
538 
539 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
540 		_leave(" = -ESTALE");
541 		return ERR_PTR(-ESTALE);
542 	}
543 
544 	key = afs_request_key(vnode->volume->cell);
545 	if (IS_ERR(key)) {
546 		_leave(" = %ld [key]", PTR_ERR(key));
547 		return ERR_CAST(key);
548 	}
549 
550 	ret = afs_validate(vnode, key);
551 	if (ret < 0) {
552 		key_put(key);
553 		_leave(" = %d [val]", ret);
554 		return ERR_PTR(ret);
555 	}
556 
557 	ret = afs_do_lookup(dir, dentry, &fid, key);
558 	if (ret < 0) {
559 		inode = afs_try_auto_mntpt(ret, dentry, dir, key, &fid);
560 		if (!IS_ERR(inode)) {
561 			key_put(key);
562 			goto success;
563 		}
564 
565 		ret = PTR_ERR(inode);
566 		key_put(key);
567 		if (ret == -ENOENT) {
568 			d_add(dentry, NULL);
569 			_leave(" = NULL [negative]");
570 			return NULL;
571 		}
572 		_leave(" = %d [do]", ret);
573 		return ERR_PTR(ret);
574 	}
575 	dentry->d_fsdata = (void *)(unsigned long) vnode->status.data_version;
576 
577 	/* instantiate the dentry */
578 	inode = afs_iget(dir->i_sb, key, &fid, NULL, NULL);
579 	key_put(key);
580 	if (IS_ERR(inode)) {
581 		_leave(" = %ld", PTR_ERR(inode));
582 		return ERR_CAST(inode);
583 	}
584 
585 success:
586 	d_add(dentry, inode);
587 	_leave(" = 0 { vn=%u u=%u } -> { ino=%lu v=%u }",
588 	       fid.vnode,
589 	       fid.unique,
590 	       dentry->d_inode->i_ino,
591 	       dentry->d_inode->i_generation);
592 
593 	return NULL;
594 }
595 
596 /*
597  * check that a dentry lookup hit has found a valid entry
598  * - NOTE! the hit can be a negative hit too, so we can't assume we have an
599  *   inode
600  */
afs_d_revalidate(struct dentry * dentry,struct nameidata * nd)601 static int afs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
602 {
603 	struct afs_vnode *vnode, *dir;
604 	struct afs_fid uninitialized_var(fid);
605 	struct dentry *parent;
606 	struct key *key;
607 	void *dir_version;
608 	int ret;
609 
610 	if (nd->flags & LOOKUP_RCU)
611 		return -ECHILD;
612 
613 	vnode = AFS_FS_I(dentry->d_inode);
614 
615 	if (dentry->d_inode)
616 		_enter("{v={%x:%u} n=%s fl=%lx},",
617 		       vnode->fid.vid, vnode->fid.vnode, dentry->d_name.name,
618 		       vnode->flags);
619 	else
620 		_enter("{neg n=%s}", dentry->d_name.name);
621 
622 	key = afs_request_key(AFS_FS_S(dentry->d_sb)->volume->cell);
623 	if (IS_ERR(key))
624 		key = NULL;
625 
626 	/* lock down the parent dentry so we can peer at it */
627 	parent = dget_parent(dentry);
628 	if (!parent->d_inode)
629 		goto out_bad;
630 
631 	dir = AFS_FS_I(parent->d_inode);
632 
633 	/* validate the parent directory */
634 	if (test_bit(AFS_VNODE_MODIFIED, &dir->flags))
635 		afs_validate(dir, key);
636 
637 	if (test_bit(AFS_VNODE_DELETED, &dir->flags)) {
638 		_debug("%s: parent dir deleted", dentry->d_name.name);
639 		goto out_bad;
640 	}
641 
642 	dir_version = (void *) (unsigned long) dir->status.data_version;
643 	if (dentry->d_fsdata == dir_version)
644 		goto out_valid; /* the dir contents are unchanged */
645 
646 	_debug("dir modified");
647 
648 	/* search the directory for this vnode */
649 	ret = afs_do_lookup(&dir->vfs_inode, dentry, &fid, key);
650 	switch (ret) {
651 	case 0:
652 		/* the filename maps to something */
653 		if (!dentry->d_inode)
654 			goto out_bad;
655 		if (is_bad_inode(dentry->d_inode)) {
656 			printk("kAFS: afs_d_revalidate: %s/%s has bad inode\n",
657 			       parent->d_name.name, dentry->d_name.name);
658 			goto out_bad;
659 		}
660 
661 		/* if the vnode ID has changed, then the dirent points to a
662 		 * different file */
663 		if (fid.vnode != vnode->fid.vnode) {
664 			_debug("%s: dirent changed [%u != %u]",
665 			       dentry->d_name.name, fid.vnode,
666 			       vnode->fid.vnode);
667 			goto not_found;
668 		}
669 
670 		/* if the vnode ID uniqifier has changed, then the file has
671 		 * been deleted and replaced, and the original vnode ID has
672 		 * been reused */
673 		if (fid.unique != vnode->fid.unique) {
674 			_debug("%s: file deleted (uq %u -> %u I:%u)",
675 			       dentry->d_name.name, fid.unique,
676 			       vnode->fid.unique,
677 			       dentry->d_inode->i_generation);
678 			spin_lock(&vnode->lock);
679 			set_bit(AFS_VNODE_DELETED, &vnode->flags);
680 			spin_unlock(&vnode->lock);
681 			goto not_found;
682 		}
683 		goto out_valid;
684 
685 	case -ENOENT:
686 		/* the filename is unknown */
687 		_debug("%s: dirent not found", dentry->d_name.name);
688 		if (dentry->d_inode)
689 			goto not_found;
690 		goto out_valid;
691 
692 	default:
693 		_debug("failed to iterate dir %s: %d",
694 		       parent->d_name.name, ret);
695 		goto out_bad;
696 	}
697 
698 out_valid:
699 	dentry->d_fsdata = dir_version;
700 out_skip:
701 	dput(parent);
702 	key_put(key);
703 	_leave(" = 1 [valid]");
704 	return 1;
705 
706 	/* the dirent, if it exists, now points to a different vnode */
707 not_found:
708 	spin_lock(&dentry->d_lock);
709 	dentry->d_flags |= DCACHE_NFSFS_RENAMED;
710 	spin_unlock(&dentry->d_lock);
711 
712 out_bad:
713 	if (dentry->d_inode) {
714 		/* don't unhash if we have submounts */
715 		if (have_submounts(dentry))
716 			goto out_skip;
717 	}
718 
719 	_debug("dropping dentry %s/%s",
720 	       parent->d_name.name, dentry->d_name.name);
721 	shrink_dcache_parent(dentry);
722 	d_drop(dentry);
723 	dput(parent);
724 	key_put(key);
725 
726 	_leave(" = 0 [bad]");
727 	return 0;
728 }
729 
730 /*
731  * allow the VFS to enquire as to whether a dentry should be unhashed (mustn't
732  * sleep)
733  * - called from dput() when d_count is going to 0.
734  * - return 1 to request dentry be unhashed, 0 otherwise
735  */
afs_d_delete(const struct dentry * dentry)736 static int afs_d_delete(const struct dentry *dentry)
737 {
738 	_enter("%s", dentry->d_name.name);
739 
740 	if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
741 		goto zap;
742 
743 	if (dentry->d_inode &&
744 	    (test_bit(AFS_VNODE_DELETED,   &AFS_FS_I(dentry->d_inode)->flags) ||
745 	     test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(dentry->d_inode)->flags)))
746 		goto zap;
747 
748 	_leave(" = 0 [keep]");
749 	return 0;
750 
751 zap:
752 	_leave(" = 1 [zap]");
753 	return 1;
754 }
755 
756 /*
757  * handle dentry release
758  */
afs_d_release(struct dentry * dentry)759 static void afs_d_release(struct dentry *dentry)
760 {
761 	_enter("%s", dentry->d_name.name);
762 }
763 
764 /*
765  * create a directory on an AFS filesystem
766  */
afs_mkdir(struct inode * dir,struct dentry * dentry,umode_t mode)767 static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
768 {
769 	struct afs_file_status status;
770 	struct afs_callback cb;
771 	struct afs_server *server;
772 	struct afs_vnode *dvnode, *vnode;
773 	struct afs_fid fid;
774 	struct inode *inode;
775 	struct key *key;
776 	int ret;
777 
778 	dvnode = AFS_FS_I(dir);
779 
780 	_enter("{%x:%u},{%s},%ho",
781 	       dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name, mode);
782 
783 	ret = -ENAMETOOLONG;
784 	if (dentry->d_name.len >= AFSNAMEMAX)
785 		goto error;
786 
787 	key = afs_request_key(dvnode->volume->cell);
788 	if (IS_ERR(key)) {
789 		ret = PTR_ERR(key);
790 		goto error;
791 	}
792 
793 	mode |= S_IFDIR;
794 	ret = afs_vnode_create(dvnode, key, dentry->d_name.name,
795 			       mode, &fid, &status, &cb, &server);
796 	if (ret < 0)
797 		goto mkdir_error;
798 
799 	inode = afs_iget(dir->i_sb, key, &fid, &status, &cb);
800 	if (IS_ERR(inode)) {
801 		/* ENOMEM at a really inconvenient time - just abandon the new
802 		 * directory on the server */
803 		ret = PTR_ERR(inode);
804 		goto iget_error;
805 	}
806 
807 	/* apply the status report we've got for the new vnode */
808 	vnode = AFS_FS_I(inode);
809 	spin_lock(&vnode->lock);
810 	vnode->update_cnt++;
811 	spin_unlock(&vnode->lock);
812 	afs_vnode_finalise_status_update(vnode, server);
813 	afs_put_server(server);
814 
815 	d_instantiate(dentry, inode);
816 	if (d_unhashed(dentry)) {
817 		_debug("not hashed");
818 		d_rehash(dentry);
819 	}
820 	key_put(key);
821 	_leave(" = 0");
822 	return 0;
823 
824 iget_error:
825 	afs_put_server(server);
826 mkdir_error:
827 	key_put(key);
828 error:
829 	d_drop(dentry);
830 	_leave(" = %d", ret);
831 	return ret;
832 }
833 
834 /*
835  * remove a directory from an AFS filesystem
836  */
afs_rmdir(struct inode * dir,struct dentry * dentry)837 static int afs_rmdir(struct inode *dir, struct dentry *dentry)
838 {
839 	struct afs_vnode *dvnode, *vnode;
840 	struct key *key;
841 	int ret;
842 
843 	dvnode = AFS_FS_I(dir);
844 
845 	_enter("{%x:%u},{%s}",
846 	       dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name);
847 
848 	ret = -ENAMETOOLONG;
849 	if (dentry->d_name.len >= AFSNAMEMAX)
850 		goto error;
851 
852 	key = afs_request_key(dvnode->volume->cell);
853 	if (IS_ERR(key)) {
854 		ret = PTR_ERR(key);
855 		goto error;
856 	}
857 
858 	ret = afs_vnode_remove(dvnode, key, dentry->d_name.name, true);
859 	if (ret < 0)
860 		goto rmdir_error;
861 
862 	if (dentry->d_inode) {
863 		vnode = AFS_FS_I(dentry->d_inode);
864 		clear_nlink(&vnode->vfs_inode);
865 		set_bit(AFS_VNODE_DELETED, &vnode->flags);
866 		afs_discard_callback_on_delete(vnode);
867 	}
868 
869 	key_put(key);
870 	_leave(" = 0");
871 	return 0;
872 
873 rmdir_error:
874 	key_put(key);
875 error:
876 	_leave(" = %d", ret);
877 	return ret;
878 }
879 
880 /*
881  * remove a file from an AFS filesystem
882  */
afs_unlink(struct inode * dir,struct dentry * dentry)883 static int afs_unlink(struct inode *dir, struct dentry *dentry)
884 {
885 	struct afs_vnode *dvnode, *vnode;
886 	struct key *key;
887 	int ret;
888 
889 	dvnode = AFS_FS_I(dir);
890 
891 	_enter("{%x:%u},{%s}",
892 	       dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name);
893 
894 	ret = -ENAMETOOLONG;
895 	if (dentry->d_name.len >= AFSNAMEMAX)
896 		goto error;
897 
898 	key = afs_request_key(dvnode->volume->cell);
899 	if (IS_ERR(key)) {
900 		ret = PTR_ERR(key);
901 		goto error;
902 	}
903 
904 	if (dentry->d_inode) {
905 		vnode = AFS_FS_I(dentry->d_inode);
906 
907 		/* make sure we have a callback promise on the victim */
908 		ret = afs_validate(vnode, key);
909 		if (ret < 0)
910 			goto error;
911 	}
912 
913 	ret = afs_vnode_remove(dvnode, key, dentry->d_name.name, false);
914 	if (ret < 0)
915 		goto remove_error;
916 
917 	if (dentry->d_inode) {
918 		/* if the file wasn't deleted due to excess hard links, the
919 		 * fileserver will break the callback promise on the file - if
920 		 * it had one - before it returns to us, and if it was deleted,
921 		 * it won't
922 		 *
923 		 * however, if we didn't have a callback promise outstanding,
924 		 * or it was outstanding on a different server, then it won't
925 		 * break it either...
926 		 */
927 		vnode = AFS_FS_I(dentry->d_inode);
928 		if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
929 			_debug("AFS_VNODE_DELETED");
930 		if (test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags))
931 			_debug("AFS_VNODE_CB_BROKEN");
932 		set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
933 		ret = afs_validate(vnode, key);
934 		_debug("nlink %d [val %d]", vnode->vfs_inode.i_nlink, ret);
935 	}
936 
937 	key_put(key);
938 	_leave(" = 0");
939 	return 0;
940 
941 remove_error:
942 	key_put(key);
943 error:
944 	_leave(" = %d", ret);
945 	return ret;
946 }
947 
948 /*
949  * create a regular file on an AFS filesystem
950  */
afs_create(struct inode * dir,struct dentry * dentry,umode_t mode,struct nameidata * nd)951 static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
952 		      struct nameidata *nd)
953 {
954 	struct afs_file_status status;
955 	struct afs_callback cb;
956 	struct afs_server *server;
957 	struct afs_vnode *dvnode, *vnode;
958 	struct afs_fid fid;
959 	struct inode *inode;
960 	struct key *key;
961 	int ret;
962 
963 	dvnode = AFS_FS_I(dir);
964 
965 	_enter("{%x:%u},{%s},%ho,",
966 	       dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name, mode);
967 
968 	ret = -ENAMETOOLONG;
969 	if (dentry->d_name.len >= AFSNAMEMAX)
970 		goto error;
971 
972 	key = afs_request_key(dvnode->volume->cell);
973 	if (IS_ERR(key)) {
974 		ret = PTR_ERR(key);
975 		goto error;
976 	}
977 
978 	mode |= S_IFREG;
979 	ret = afs_vnode_create(dvnode, key, dentry->d_name.name,
980 			       mode, &fid, &status, &cb, &server);
981 	if (ret < 0)
982 		goto create_error;
983 
984 	inode = afs_iget(dir->i_sb, key, &fid, &status, &cb);
985 	if (IS_ERR(inode)) {
986 		/* ENOMEM at a really inconvenient time - just abandon the new
987 		 * directory on the server */
988 		ret = PTR_ERR(inode);
989 		goto iget_error;
990 	}
991 
992 	/* apply the status report we've got for the new vnode */
993 	vnode = AFS_FS_I(inode);
994 	spin_lock(&vnode->lock);
995 	vnode->update_cnt++;
996 	spin_unlock(&vnode->lock);
997 	afs_vnode_finalise_status_update(vnode, server);
998 	afs_put_server(server);
999 
1000 	d_instantiate(dentry, inode);
1001 	if (d_unhashed(dentry)) {
1002 		_debug("not hashed");
1003 		d_rehash(dentry);
1004 	}
1005 	key_put(key);
1006 	_leave(" = 0");
1007 	return 0;
1008 
1009 iget_error:
1010 	afs_put_server(server);
1011 create_error:
1012 	key_put(key);
1013 error:
1014 	d_drop(dentry);
1015 	_leave(" = %d", ret);
1016 	return ret;
1017 }
1018 
1019 /*
1020  * create a hard link between files in an AFS filesystem
1021  */
afs_link(struct dentry * from,struct inode * dir,struct dentry * dentry)1022 static int afs_link(struct dentry *from, struct inode *dir,
1023 		    struct dentry *dentry)
1024 {
1025 	struct afs_vnode *dvnode, *vnode;
1026 	struct key *key;
1027 	int ret;
1028 
1029 	vnode = AFS_FS_I(from->d_inode);
1030 	dvnode = AFS_FS_I(dir);
1031 
1032 	_enter("{%x:%u},{%x:%u},{%s}",
1033 	       vnode->fid.vid, vnode->fid.vnode,
1034 	       dvnode->fid.vid, dvnode->fid.vnode,
1035 	       dentry->d_name.name);
1036 
1037 	ret = -ENAMETOOLONG;
1038 	if (dentry->d_name.len >= AFSNAMEMAX)
1039 		goto error;
1040 
1041 	key = afs_request_key(dvnode->volume->cell);
1042 	if (IS_ERR(key)) {
1043 		ret = PTR_ERR(key);
1044 		goto error;
1045 	}
1046 
1047 	ret = afs_vnode_link(dvnode, vnode, key, dentry->d_name.name);
1048 	if (ret < 0)
1049 		goto link_error;
1050 
1051 	ihold(&vnode->vfs_inode);
1052 	d_instantiate(dentry, &vnode->vfs_inode);
1053 	key_put(key);
1054 	_leave(" = 0");
1055 	return 0;
1056 
1057 link_error:
1058 	key_put(key);
1059 error:
1060 	d_drop(dentry);
1061 	_leave(" = %d", ret);
1062 	return ret;
1063 }
1064 
1065 /*
1066  * create a symlink in an AFS filesystem
1067  */
afs_symlink(struct inode * dir,struct dentry * dentry,const char * content)1068 static int afs_symlink(struct inode *dir, struct dentry *dentry,
1069 		       const char *content)
1070 {
1071 	struct afs_file_status status;
1072 	struct afs_server *server;
1073 	struct afs_vnode *dvnode, *vnode;
1074 	struct afs_fid fid;
1075 	struct inode *inode;
1076 	struct key *key;
1077 	int ret;
1078 
1079 	dvnode = AFS_FS_I(dir);
1080 
1081 	_enter("{%x:%u},{%s},%s",
1082 	       dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name,
1083 	       content);
1084 
1085 	ret = -ENAMETOOLONG;
1086 	if (dentry->d_name.len >= AFSNAMEMAX)
1087 		goto error;
1088 
1089 	ret = -EINVAL;
1090 	if (strlen(content) >= AFSPATHMAX)
1091 		goto error;
1092 
1093 	key = afs_request_key(dvnode->volume->cell);
1094 	if (IS_ERR(key)) {
1095 		ret = PTR_ERR(key);
1096 		goto error;
1097 	}
1098 
1099 	ret = afs_vnode_symlink(dvnode, key, dentry->d_name.name, content,
1100 				&fid, &status, &server);
1101 	if (ret < 0)
1102 		goto create_error;
1103 
1104 	inode = afs_iget(dir->i_sb, key, &fid, &status, NULL);
1105 	if (IS_ERR(inode)) {
1106 		/* ENOMEM at a really inconvenient time - just abandon the new
1107 		 * directory on the server */
1108 		ret = PTR_ERR(inode);
1109 		goto iget_error;
1110 	}
1111 
1112 	/* apply the status report we've got for the new vnode */
1113 	vnode = AFS_FS_I(inode);
1114 	spin_lock(&vnode->lock);
1115 	vnode->update_cnt++;
1116 	spin_unlock(&vnode->lock);
1117 	afs_vnode_finalise_status_update(vnode, server);
1118 	afs_put_server(server);
1119 
1120 	d_instantiate(dentry, inode);
1121 	if (d_unhashed(dentry)) {
1122 		_debug("not hashed");
1123 		d_rehash(dentry);
1124 	}
1125 	key_put(key);
1126 	_leave(" = 0");
1127 	return 0;
1128 
1129 iget_error:
1130 	afs_put_server(server);
1131 create_error:
1132 	key_put(key);
1133 error:
1134 	d_drop(dentry);
1135 	_leave(" = %d", ret);
1136 	return ret;
1137 }
1138 
1139 /*
1140  * rename a file in an AFS filesystem and/or move it between directories
1141  */
afs_rename(struct inode * old_dir,struct dentry * old_dentry,struct inode * new_dir,struct dentry * new_dentry)1142 static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
1143 		      struct inode *new_dir, struct dentry *new_dentry)
1144 {
1145 	struct afs_vnode *orig_dvnode, *new_dvnode, *vnode;
1146 	struct key *key;
1147 	int ret;
1148 
1149 	vnode = AFS_FS_I(old_dentry->d_inode);
1150 	orig_dvnode = AFS_FS_I(old_dir);
1151 	new_dvnode = AFS_FS_I(new_dir);
1152 
1153 	_enter("{%x:%u},{%x:%u},{%x:%u},{%s}",
1154 	       orig_dvnode->fid.vid, orig_dvnode->fid.vnode,
1155 	       vnode->fid.vid, vnode->fid.vnode,
1156 	       new_dvnode->fid.vid, new_dvnode->fid.vnode,
1157 	       new_dentry->d_name.name);
1158 
1159 	ret = -ENAMETOOLONG;
1160 	if (new_dentry->d_name.len >= AFSNAMEMAX)
1161 		goto error;
1162 
1163 	key = afs_request_key(orig_dvnode->volume->cell);
1164 	if (IS_ERR(key)) {
1165 		ret = PTR_ERR(key);
1166 		goto error;
1167 	}
1168 
1169 	ret = afs_vnode_rename(orig_dvnode, new_dvnode, key,
1170 			       old_dentry->d_name.name,
1171 			       new_dentry->d_name.name);
1172 	if (ret < 0)
1173 		goto rename_error;
1174 	key_put(key);
1175 	_leave(" = 0");
1176 	return 0;
1177 
1178 rename_error:
1179 	key_put(key);
1180 error:
1181 	d_drop(new_dentry);
1182 	_leave(" = %d", ret);
1183 	return ret;
1184 }
1185