xref: /linux/fs/afs/dir.c (revision d257f9bf06129613de539ea71ecea60848b662cd)
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 				 unsigned int flags);
24 static int afs_dir_open(struct inode *inode, struct file *file);
25 static int afs_readdir(struct file *file, struct dir_context *ctx);
26 static int afs_d_revalidate(struct dentry *dentry, unsigned int flags);
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(struct dir_context *ctx, 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 		      bool excl);
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 		      unsigned int flags);
43 
44 const struct file_operations afs_dir_file_operations = {
45 	.open		= afs_dir_open,
46 	.release	= afs_release,
47 	.iterate_shared	= afs_readdir,
48 	.lock		= afs_lock,
49 	.llseek		= generic_file_llseek,
50 };
51 
52 const struct inode_operations afs_dir_inode_operations = {
53 	.create		= afs_create,
54 	.lookup		= afs_lookup,
55 	.link		= afs_link,
56 	.unlink		= afs_unlink,
57 	.symlink	= afs_symlink,
58 	.mkdir		= afs_mkdir,
59 	.rmdir		= afs_rmdir,
60 	.rename		= afs_rename,
61 	.permission	= afs_permission,
62 	.getattr	= afs_getattr,
63 	.setattr	= afs_setattr,
64 	.listxattr	= afs_listxattr,
65 };
66 
67 const struct dentry_operations afs_fs_dentry_operations = {
68 	.d_revalidate	= afs_d_revalidate,
69 	.d_delete	= afs_d_delete,
70 	.d_release	= afs_d_release,
71 	.d_automount	= afs_d_automount,
72 };
73 
74 #define AFS_DIR_HASHTBL_SIZE	128
75 #define AFS_DIR_DIRENT_SIZE	32
76 #define AFS_DIRENT_PER_BLOCK	64
77 
78 union afs_dirent {
79 	struct {
80 		uint8_t		valid;
81 		uint8_t		unused[1];
82 		__be16		hash_next;
83 		__be32		vnode;
84 		__be32		unique;
85 		uint8_t		name[16];
86 		uint8_t		overflow[4];	/* if any char of the name (inc
87 						 * NUL) reaches here, consume
88 						 * the next dirent too */
89 	} u;
90 	uint8_t	extended_name[32];
91 };
92 
93 /* AFS directory page header (one at the beginning of every 2048-byte chunk) */
94 struct afs_dir_pagehdr {
95 	__be16		npages;
96 	__be16		magic;
97 #define AFS_DIR_MAGIC htons(1234)
98 	uint8_t		nentries;
99 	uint8_t		bitmap[8];
100 	uint8_t		pad[19];
101 };
102 
103 /* directory block layout */
104 union afs_dir_block {
105 
106 	struct afs_dir_pagehdr pagehdr;
107 
108 	struct {
109 		struct afs_dir_pagehdr	pagehdr;
110 		uint8_t			alloc_ctrs[128];
111 		/* dir hash table */
112 		uint16_t		hashtable[AFS_DIR_HASHTBL_SIZE];
113 	} hdr;
114 
115 	union afs_dirent dirents[AFS_DIRENT_PER_BLOCK];
116 };
117 
118 /* layout on a linux VM page */
119 struct afs_dir_page {
120 	union afs_dir_block blocks[PAGE_SIZE / sizeof(union afs_dir_block)];
121 };
122 
123 struct afs_lookup_cookie {
124 	struct dir_context ctx;
125 	struct afs_fid	fid;
126 	struct qstr name;
127 	int		found;
128 };
129 
130 /*
131  * check that a directory page is valid
132  */
133 static inline bool afs_dir_check_page(struct inode *dir, struct page *page)
134 {
135 	struct afs_dir_page *dbuf;
136 	loff_t latter;
137 	int tmp, qty;
138 
139 #if 0
140 	/* check the page count */
141 	qty = desc.size / sizeof(dbuf->blocks[0]);
142 	if (qty == 0)
143 		goto error;
144 
145 	if (page->index == 0 && qty != ntohs(dbuf->blocks[0].pagehdr.npages)) {
146 		printk("kAFS: %s(%lu): wrong number of dir blocks %d!=%hu\n",
147 		       __func__, dir->i_ino, qty,
148 		       ntohs(dbuf->blocks[0].pagehdr.npages));
149 		goto error;
150 	}
151 #endif
152 
153 	/* determine how many magic numbers there should be in this page */
154 	latter = dir->i_size - page_offset(page);
155 	if (latter >= PAGE_SIZE)
156 		qty = PAGE_SIZE;
157 	else
158 		qty = latter;
159 	qty /= sizeof(union afs_dir_block);
160 
161 	/* check them */
162 	dbuf = page_address(page);
163 	for (tmp = 0; tmp < qty; tmp++) {
164 		if (dbuf->blocks[tmp].pagehdr.magic != AFS_DIR_MAGIC) {
165 			printk("kAFS: %s(%lu): bad magic %d/%d is %04hx\n",
166 			       __func__, dir->i_ino, tmp, qty,
167 			       ntohs(dbuf->blocks[tmp].pagehdr.magic));
168 			goto error;
169 		}
170 	}
171 
172 	SetPageChecked(page);
173 	return true;
174 
175 error:
176 	SetPageError(page);
177 	return false;
178 }
179 
180 /*
181  * discard a page cached in the pagecache
182  */
183 static inline void afs_dir_put_page(struct page *page)
184 {
185 	kunmap(page);
186 	put_page(page);
187 }
188 
189 /*
190  * get a page into the pagecache
191  */
192 static struct page *afs_dir_get_page(struct inode *dir, unsigned long index,
193 				     struct key *key)
194 {
195 	struct page *page;
196 	_enter("{%lu},%lu", dir->i_ino, index);
197 
198 	page = read_cache_page(dir->i_mapping, index, afs_page_filler, key);
199 	if (!IS_ERR(page)) {
200 		kmap(page);
201 		if (unlikely(!PageChecked(page))) {
202 			if (PageError(page) || !afs_dir_check_page(dir, page))
203 				goto fail;
204 		}
205 	}
206 	return page;
207 
208 fail:
209 	afs_dir_put_page(page);
210 	_leave(" = -EIO");
211 	return ERR_PTR(-EIO);
212 }
213 
214 /*
215  * open an AFS directory file
216  */
217 static int afs_dir_open(struct inode *inode, struct file *file)
218 {
219 	_enter("{%lu}", inode->i_ino);
220 
221 	BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);
222 	BUILD_BUG_ON(sizeof(union afs_dirent) != 32);
223 
224 	if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(inode)->flags))
225 		return -ENOENT;
226 
227 	return afs_open(inode, file);
228 }
229 
230 /*
231  * deal with one block in an AFS directory
232  */
233 static int afs_dir_iterate_block(struct dir_context *ctx,
234 				 union afs_dir_block *block,
235 				 unsigned blkoff)
236 {
237 	union afs_dirent *dire;
238 	unsigned offset, next, curr;
239 	size_t nlen;
240 	int tmp;
241 
242 	_enter("%u,%x,%p,,",(unsigned)ctx->pos,blkoff,block);
243 
244 	curr = (ctx->pos - 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 				ctx->pos = 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 		if (!dir_emit(ctx, dire->u.name, nlen,
306 			      ntohl(dire->u.vnode),
307 			      ctx->actor == afs_lookup_filldir ?
308 			      ntohl(dire->u.unique) : DT_UNKNOWN)) {
309 			_leave(" = 0 [full]");
310 			return 0;
311 		}
312 
313 		ctx->pos = blkoff + next * sizeof(union afs_dirent);
314 	}
315 
316 	_leave(" = 1 [more]");
317 	return 1;
318 }
319 
320 /*
321  * iterate through the data blob that lists the contents of an AFS directory
322  */
323 static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
324 			   struct key *key)
325 {
326 	union afs_dir_block *dblock;
327 	struct afs_dir_page *dbuf;
328 	struct page *page;
329 	unsigned blkoff, limit;
330 	int ret;
331 
332 	_enter("{%lu},%u,,", dir->i_ino, (unsigned)ctx->pos);
333 
334 	if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(dir)->flags)) {
335 		_leave(" = -ESTALE");
336 		return -ESTALE;
337 	}
338 
339 	/* round the file position up to the next entry boundary */
340 	ctx->pos += sizeof(union afs_dirent) - 1;
341 	ctx->pos &= ~(sizeof(union afs_dirent) - 1);
342 
343 	/* walk through the blocks in sequence */
344 	ret = 0;
345 	while (ctx->pos < dir->i_size) {
346 		blkoff = ctx->pos & ~(sizeof(union afs_dir_block) - 1);
347 
348 		/* fetch the appropriate page from the directory */
349 		page = afs_dir_get_page(dir, blkoff / PAGE_SIZE, key);
350 		if (IS_ERR(page)) {
351 			ret = PTR_ERR(page);
352 			break;
353 		}
354 
355 		limit = blkoff & ~(PAGE_SIZE - 1);
356 
357 		dbuf = page_address(page);
358 
359 		/* deal with the individual blocks stashed on this page */
360 		do {
361 			dblock = &dbuf->blocks[(blkoff % PAGE_SIZE) /
362 					       sizeof(union afs_dir_block)];
363 			ret = afs_dir_iterate_block(ctx, dblock, blkoff);
364 			if (ret != 1) {
365 				afs_dir_put_page(page);
366 				goto out;
367 			}
368 
369 			blkoff += sizeof(union afs_dir_block);
370 
371 		} while (ctx->pos < dir->i_size && blkoff < limit);
372 
373 		afs_dir_put_page(page);
374 		ret = 0;
375 	}
376 
377 out:
378 	_leave(" = %d", ret);
379 	return ret;
380 }
381 
382 /*
383  * read an AFS directory
384  */
385 static int afs_readdir(struct file *file, struct dir_context *ctx)
386 {
387 	return afs_dir_iterate(file_inode(file),
388 			      ctx, file->private_data);
389 }
390 
391 /*
392  * search the directory for a name
393  * - if afs_dir_iterate_block() spots this function, it'll pass the FID
394  *   uniquifier through dtype
395  */
396 static int afs_lookup_filldir(struct dir_context *ctx, const char *name,
397 			      int nlen, loff_t fpos, u64 ino, unsigned dtype)
398 {
399 	struct afs_lookup_cookie *cookie =
400 		container_of(ctx, struct afs_lookup_cookie, ctx);
401 
402 	_enter("{%s,%u},%s,%u,,%llu,%u",
403 	       cookie->name.name, cookie->name.len, name, nlen,
404 	       (unsigned long long) ino, dtype);
405 
406 	/* insanity checks first */
407 	BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);
408 	BUILD_BUG_ON(sizeof(union afs_dirent) != 32);
409 
410 	if (cookie->name.len != nlen ||
411 	    memcmp(cookie->name.name, name, nlen) != 0) {
412 		_leave(" = 0 [no]");
413 		return 0;
414 	}
415 
416 	cookie->fid.vnode = ino;
417 	cookie->fid.unique = dtype;
418 	cookie->found = 1;
419 
420 	_leave(" = -1 [found]");
421 	return -1;
422 }
423 
424 /*
425  * do a lookup in a directory
426  * - just returns the FID the dentry name maps to if found
427  */
428 static int afs_do_lookup(struct inode *dir, struct dentry *dentry,
429 			 struct afs_fid *fid, struct key *key)
430 {
431 	struct afs_super_info *as = dir->i_sb->s_fs_info;
432 	struct afs_lookup_cookie cookie = {
433 		.ctx.actor = afs_lookup_filldir,
434 		.name = dentry->d_name,
435 		.fid.vid = as->volume->vid
436 	};
437 	int ret;
438 
439 	_enter("{%lu},%p{%pd},", dir->i_ino, dentry, dentry);
440 
441 	/* search the directory */
442 	ret = afs_dir_iterate(dir, &cookie.ctx, key);
443 	if (ret < 0) {
444 		_leave(" = %d [iter]", ret);
445 		return ret;
446 	}
447 
448 	ret = -ENOENT;
449 	if (!cookie.found) {
450 		_leave(" = -ENOENT [not found]");
451 		return -ENOENT;
452 	}
453 
454 	*fid = cookie.fid;
455 	_leave(" = 0 { vn=%u u=%u }", fid->vnode, fid->unique);
456 	return 0;
457 }
458 
459 /*
460  * Try to auto mount the mountpoint with pseudo directory, if the autocell
461  * operation is setted.
462  */
463 static struct inode *afs_try_auto_mntpt(
464 	int ret, struct dentry *dentry, struct inode *dir, struct key *key,
465 	struct afs_fid *fid)
466 {
467 	const char *devname = dentry->d_name.name;
468 	struct afs_vnode *vnode = AFS_FS_I(dir);
469 	struct inode *inode;
470 
471 	_enter("%d, %p{%pd}, {%x:%u}, %p",
472 	       ret, dentry, dentry, vnode->fid.vid, vnode->fid.vnode, key);
473 
474 	if (ret != -ENOENT ||
475 	    !test_bit(AFS_VNODE_AUTOCELL, &vnode->flags))
476 		goto out;
477 
478 	inode = afs_iget_autocell(dir, devname, strlen(devname), key);
479 	if (IS_ERR(inode)) {
480 		ret = PTR_ERR(inode);
481 		goto out;
482 	}
483 
484 	*fid = AFS_FS_I(inode)->fid;
485 	_leave("= %p", inode);
486 	return inode;
487 
488 out:
489 	_leave("= %d", ret);
490 	return ERR_PTR(ret);
491 }
492 
493 /*
494  * look up an entry in a directory
495  */
496 static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
497 				 unsigned int flags)
498 {
499 	struct afs_vnode *vnode;
500 	struct afs_fid fid;
501 	struct inode *inode;
502 	struct key *key;
503 	int ret;
504 
505 	vnode = AFS_FS_I(dir);
506 
507 	_enter("{%x:%u},%p{%pd},",
508 	       vnode->fid.vid, vnode->fid.vnode, dentry, dentry);
509 
510 	ASSERTCMP(d_inode(dentry), ==, NULL);
511 
512 	if (dentry->d_name.len >= AFSNAMEMAX) {
513 		_leave(" = -ENAMETOOLONG");
514 		return ERR_PTR(-ENAMETOOLONG);
515 	}
516 
517 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
518 		_leave(" = -ESTALE");
519 		return ERR_PTR(-ESTALE);
520 	}
521 
522 	key = afs_request_key(vnode->volume->cell);
523 	if (IS_ERR(key)) {
524 		_leave(" = %ld [key]", PTR_ERR(key));
525 		return ERR_CAST(key);
526 	}
527 
528 	ret = afs_validate(vnode, key);
529 	if (ret < 0) {
530 		key_put(key);
531 		_leave(" = %d [val]", ret);
532 		return ERR_PTR(ret);
533 	}
534 
535 	ret = afs_do_lookup(dir, dentry, &fid, key);
536 	if (ret < 0) {
537 		inode = afs_try_auto_mntpt(ret, dentry, dir, key, &fid);
538 		if (!IS_ERR(inode)) {
539 			key_put(key);
540 			goto success;
541 		}
542 
543 		ret = PTR_ERR(inode);
544 		key_put(key);
545 		if (ret == -ENOENT) {
546 			d_add(dentry, NULL);
547 			_leave(" = NULL [negative]");
548 			return NULL;
549 		}
550 		_leave(" = %d [do]", ret);
551 		return ERR_PTR(ret);
552 	}
553 	dentry->d_fsdata = (void *)(unsigned long) vnode->status.data_version;
554 
555 	/* instantiate the dentry */
556 	inode = afs_iget(dir->i_sb, key, &fid, NULL, NULL);
557 	key_put(key);
558 	if (IS_ERR(inode)) {
559 		_leave(" = %ld", PTR_ERR(inode));
560 		return ERR_CAST(inode);
561 	}
562 
563 success:
564 	d_add(dentry, inode);
565 	_leave(" = 0 { vn=%u u=%u } -> { ino=%lu v=%u }",
566 	       fid.vnode,
567 	       fid.unique,
568 	       d_inode(dentry)->i_ino,
569 	       d_inode(dentry)->i_generation);
570 
571 	return NULL;
572 }
573 
574 /*
575  * check that a dentry lookup hit has found a valid entry
576  * - NOTE! the hit can be a negative hit too, so we can't assume we have an
577  *   inode
578  */
579 static int afs_d_revalidate(struct dentry *dentry, unsigned int flags)
580 {
581 	struct afs_vnode *vnode, *dir;
582 	struct afs_fid uninitialized_var(fid);
583 	struct dentry *parent;
584 	struct key *key;
585 	void *dir_version;
586 	int ret;
587 
588 	if (flags & LOOKUP_RCU)
589 		return -ECHILD;
590 
591 	vnode = AFS_FS_I(d_inode(dentry));
592 
593 	if (d_really_is_positive(dentry))
594 		_enter("{v={%x:%u} n=%pd fl=%lx},",
595 		       vnode->fid.vid, vnode->fid.vnode, dentry,
596 		       vnode->flags);
597 	else
598 		_enter("{neg n=%pd}", dentry);
599 
600 	key = afs_request_key(AFS_FS_S(dentry->d_sb)->volume->cell);
601 	if (IS_ERR(key))
602 		key = NULL;
603 
604 	/* lock down the parent dentry so we can peer at it */
605 	parent = dget_parent(dentry);
606 	dir = AFS_FS_I(d_inode(parent));
607 
608 	/* validate the parent directory */
609 	if (test_bit(AFS_VNODE_MODIFIED, &dir->flags))
610 		afs_validate(dir, key);
611 
612 	if (test_bit(AFS_VNODE_DELETED, &dir->flags)) {
613 		_debug("%pd: parent dir deleted", dentry);
614 		goto out_bad;
615 	}
616 
617 	dir_version = (void *) (unsigned long) dir->status.data_version;
618 	if (dentry->d_fsdata == dir_version)
619 		goto out_valid; /* the dir contents are unchanged */
620 
621 	_debug("dir modified");
622 
623 	/* search the directory for this vnode */
624 	ret = afs_do_lookup(&dir->vfs_inode, dentry, &fid, key);
625 	switch (ret) {
626 	case 0:
627 		/* the filename maps to something */
628 		if (d_really_is_negative(dentry))
629 			goto out_bad;
630 		if (is_bad_inode(d_inode(dentry))) {
631 			printk("kAFS: afs_d_revalidate: %pd2 has bad inode\n",
632 			       dentry);
633 			goto out_bad;
634 		}
635 
636 		/* if the vnode ID has changed, then the dirent points to a
637 		 * different file */
638 		if (fid.vnode != vnode->fid.vnode) {
639 			_debug("%pd: dirent changed [%u != %u]",
640 			       dentry, fid.vnode,
641 			       vnode->fid.vnode);
642 			goto not_found;
643 		}
644 
645 		/* if the vnode ID uniqifier has changed, then the file has
646 		 * been deleted and replaced, and the original vnode ID has
647 		 * been reused */
648 		if (fid.unique != vnode->fid.unique) {
649 			_debug("%pd: file deleted (uq %u -> %u I:%u)",
650 			       dentry, fid.unique,
651 			       vnode->fid.unique,
652 			       d_inode(dentry)->i_generation);
653 			spin_lock(&vnode->lock);
654 			set_bit(AFS_VNODE_DELETED, &vnode->flags);
655 			spin_unlock(&vnode->lock);
656 			goto not_found;
657 		}
658 		goto out_valid;
659 
660 	case -ENOENT:
661 		/* the filename is unknown */
662 		_debug("%pd: dirent not found", dentry);
663 		if (d_really_is_positive(dentry))
664 			goto not_found;
665 		goto out_valid;
666 
667 	default:
668 		_debug("failed to iterate dir %pd: %d",
669 		       parent, ret);
670 		goto out_bad;
671 	}
672 
673 out_valid:
674 	dentry->d_fsdata = dir_version;
675 	dput(parent);
676 	key_put(key);
677 	_leave(" = 1 [valid]");
678 	return 1;
679 
680 	/* the dirent, if it exists, now points to a different vnode */
681 not_found:
682 	spin_lock(&dentry->d_lock);
683 	dentry->d_flags |= DCACHE_NFSFS_RENAMED;
684 	spin_unlock(&dentry->d_lock);
685 
686 out_bad:
687 	_debug("dropping dentry %pd2", dentry);
688 	dput(parent);
689 	key_put(key);
690 
691 	_leave(" = 0 [bad]");
692 	return 0;
693 }
694 
695 /*
696  * allow the VFS to enquire as to whether a dentry should be unhashed (mustn't
697  * sleep)
698  * - called from dput() when d_count is going to 0.
699  * - return 1 to request dentry be unhashed, 0 otherwise
700  */
701 static int afs_d_delete(const struct dentry *dentry)
702 {
703 	_enter("%pd", dentry);
704 
705 	if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
706 		goto zap;
707 
708 	if (d_really_is_positive(dentry) &&
709 	    (test_bit(AFS_VNODE_DELETED,   &AFS_FS_I(d_inode(dentry))->flags) ||
710 	     test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(d_inode(dentry))->flags)))
711 		goto zap;
712 
713 	_leave(" = 0 [keep]");
714 	return 0;
715 
716 zap:
717 	_leave(" = 1 [zap]");
718 	return 1;
719 }
720 
721 /*
722  * handle dentry release
723  */
724 static void afs_d_release(struct dentry *dentry)
725 {
726 	_enter("%pd", dentry);
727 }
728 
729 /*
730  * create a directory on an AFS filesystem
731  */
732 static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
733 {
734 	struct afs_file_status status;
735 	struct afs_callback cb;
736 	struct afs_server *server;
737 	struct afs_vnode *dvnode, *vnode;
738 	struct afs_fid fid;
739 	struct inode *inode;
740 	struct key *key;
741 	int ret;
742 
743 	dvnode = AFS_FS_I(dir);
744 
745 	_enter("{%x:%u},{%pd},%ho",
746 	       dvnode->fid.vid, dvnode->fid.vnode, dentry, mode);
747 
748 	key = afs_request_key(dvnode->volume->cell);
749 	if (IS_ERR(key)) {
750 		ret = PTR_ERR(key);
751 		goto error;
752 	}
753 
754 	mode |= S_IFDIR;
755 	ret = afs_vnode_create(dvnode, key, dentry->d_name.name,
756 			       mode, &fid, &status, &cb, &server);
757 	if (ret < 0)
758 		goto mkdir_error;
759 
760 	inode = afs_iget(dir->i_sb, key, &fid, &status, &cb);
761 	if (IS_ERR(inode)) {
762 		/* ENOMEM at a really inconvenient time - just abandon the new
763 		 * directory on the server */
764 		ret = PTR_ERR(inode);
765 		goto iget_error;
766 	}
767 
768 	/* apply the status report we've got for the new vnode */
769 	vnode = AFS_FS_I(inode);
770 	spin_lock(&vnode->lock);
771 	vnode->update_cnt++;
772 	spin_unlock(&vnode->lock);
773 	afs_vnode_finalise_status_update(vnode, server);
774 	afs_put_server(server);
775 
776 	d_instantiate(dentry, inode);
777 	if (d_unhashed(dentry)) {
778 		_debug("not hashed");
779 		d_rehash(dentry);
780 	}
781 	key_put(key);
782 	_leave(" = 0");
783 	return 0;
784 
785 iget_error:
786 	afs_put_server(server);
787 mkdir_error:
788 	key_put(key);
789 error:
790 	d_drop(dentry);
791 	_leave(" = %d", ret);
792 	return ret;
793 }
794 
795 /*
796  * remove a directory from an AFS filesystem
797  */
798 static int afs_rmdir(struct inode *dir, struct dentry *dentry)
799 {
800 	struct afs_vnode *dvnode, *vnode;
801 	struct key *key;
802 	int ret;
803 
804 	dvnode = AFS_FS_I(dir);
805 
806 	_enter("{%x:%u},{%pd}",
807 	       dvnode->fid.vid, dvnode->fid.vnode, dentry);
808 
809 	key = afs_request_key(dvnode->volume->cell);
810 	if (IS_ERR(key)) {
811 		ret = PTR_ERR(key);
812 		goto error;
813 	}
814 
815 	ret = afs_vnode_remove(dvnode, key, dentry->d_name.name, true);
816 	if (ret < 0)
817 		goto rmdir_error;
818 
819 	if (d_really_is_positive(dentry)) {
820 		vnode = AFS_FS_I(d_inode(dentry));
821 		clear_nlink(&vnode->vfs_inode);
822 		set_bit(AFS_VNODE_DELETED, &vnode->flags);
823 		afs_discard_callback_on_delete(vnode);
824 	}
825 
826 	key_put(key);
827 	_leave(" = 0");
828 	return 0;
829 
830 rmdir_error:
831 	key_put(key);
832 error:
833 	_leave(" = %d", ret);
834 	return ret;
835 }
836 
837 /*
838  * remove a file from an AFS filesystem
839  */
840 static int afs_unlink(struct inode *dir, struct dentry *dentry)
841 {
842 	struct afs_vnode *dvnode, *vnode;
843 	struct key *key;
844 	int ret;
845 
846 	dvnode = AFS_FS_I(dir);
847 
848 	_enter("{%x:%u},{%pd}",
849 	       dvnode->fid.vid, dvnode->fid.vnode, dentry);
850 
851 	ret = -ENAMETOOLONG;
852 	if (dentry->d_name.len >= AFSNAMEMAX)
853 		goto error;
854 
855 	key = afs_request_key(dvnode->volume->cell);
856 	if (IS_ERR(key)) {
857 		ret = PTR_ERR(key);
858 		goto error;
859 	}
860 
861 	if (d_really_is_positive(dentry)) {
862 		vnode = AFS_FS_I(d_inode(dentry));
863 
864 		/* make sure we have a callback promise on the victim */
865 		ret = afs_validate(vnode, key);
866 		if (ret < 0)
867 			goto error;
868 	}
869 
870 	ret = afs_vnode_remove(dvnode, key, dentry->d_name.name, false);
871 	if (ret < 0)
872 		goto remove_error;
873 
874 	if (d_really_is_positive(dentry)) {
875 		/* if the file wasn't deleted due to excess hard links, the
876 		 * fileserver will break the callback promise on the file - if
877 		 * it had one - before it returns to us, and if it was deleted,
878 		 * it won't
879 		 *
880 		 * however, if we didn't have a callback promise outstanding,
881 		 * or it was outstanding on a different server, then it won't
882 		 * break it either...
883 		 */
884 		vnode = AFS_FS_I(d_inode(dentry));
885 		if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
886 			_debug("AFS_VNODE_DELETED");
887 		if (test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags))
888 			_debug("AFS_VNODE_CB_BROKEN");
889 		set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
890 		ret = afs_validate(vnode, key);
891 		_debug("nlink %d [val %d]", vnode->vfs_inode.i_nlink, ret);
892 	}
893 
894 	key_put(key);
895 	_leave(" = 0");
896 	return 0;
897 
898 remove_error:
899 	key_put(key);
900 error:
901 	_leave(" = %d", ret);
902 	return ret;
903 }
904 
905 /*
906  * create a regular file on an AFS filesystem
907  */
908 static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
909 		      bool excl)
910 {
911 	struct afs_file_status status;
912 	struct afs_callback cb;
913 	struct afs_server *server;
914 	struct afs_vnode *dvnode, *vnode;
915 	struct afs_fid fid;
916 	struct inode *inode;
917 	struct key *key;
918 	int ret;
919 
920 	dvnode = AFS_FS_I(dir);
921 
922 	_enter("{%x:%u},{%pd},%ho,",
923 	       dvnode->fid.vid, dvnode->fid.vnode, dentry, mode);
924 
925 	key = afs_request_key(dvnode->volume->cell);
926 	if (IS_ERR(key)) {
927 		ret = PTR_ERR(key);
928 		goto error;
929 	}
930 
931 	mode |= S_IFREG;
932 	ret = afs_vnode_create(dvnode, key, dentry->d_name.name,
933 			       mode, &fid, &status, &cb, &server);
934 	if (ret < 0)
935 		goto create_error;
936 
937 	inode = afs_iget(dir->i_sb, key, &fid, &status, &cb);
938 	if (IS_ERR(inode)) {
939 		/* ENOMEM at a really inconvenient time - just abandon the new
940 		 * directory on the server */
941 		ret = PTR_ERR(inode);
942 		goto iget_error;
943 	}
944 
945 	/* apply the status report we've got for the new vnode */
946 	vnode = AFS_FS_I(inode);
947 	spin_lock(&vnode->lock);
948 	vnode->update_cnt++;
949 	spin_unlock(&vnode->lock);
950 	afs_vnode_finalise_status_update(vnode, server);
951 	afs_put_server(server);
952 
953 	d_instantiate(dentry, inode);
954 	if (d_unhashed(dentry)) {
955 		_debug("not hashed");
956 		d_rehash(dentry);
957 	}
958 	key_put(key);
959 	_leave(" = 0");
960 	return 0;
961 
962 iget_error:
963 	afs_put_server(server);
964 create_error:
965 	key_put(key);
966 error:
967 	d_drop(dentry);
968 	_leave(" = %d", ret);
969 	return ret;
970 }
971 
972 /*
973  * create a hard link between files in an AFS filesystem
974  */
975 static int afs_link(struct dentry *from, struct inode *dir,
976 		    struct dentry *dentry)
977 {
978 	struct afs_vnode *dvnode, *vnode;
979 	struct key *key;
980 	int ret;
981 
982 	vnode = AFS_FS_I(d_inode(from));
983 	dvnode = AFS_FS_I(dir);
984 
985 	_enter("{%x:%u},{%x:%u},{%pd}",
986 	       vnode->fid.vid, vnode->fid.vnode,
987 	       dvnode->fid.vid, dvnode->fid.vnode,
988 	       dentry);
989 
990 	key = afs_request_key(dvnode->volume->cell);
991 	if (IS_ERR(key)) {
992 		ret = PTR_ERR(key);
993 		goto error;
994 	}
995 
996 	ret = afs_vnode_link(dvnode, vnode, key, dentry->d_name.name);
997 	if (ret < 0)
998 		goto link_error;
999 
1000 	ihold(&vnode->vfs_inode);
1001 	d_instantiate(dentry, &vnode->vfs_inode);
1002 	key_put(key);
1003 	_leave(" = 0");
1004 	return 0;
1005 
1006 link_error:
1007 	key_put(key);
1008 error:
1009 	d_drop(dentry);
1010 	_leave(" = %d", ret);
1011 	return ret;
1012 }
1013 
1014 /*
1015  * create a symlink in an AFS filesystem
1016  */
1017 static int afs_symlink(struct inode *dir, struct dentry *dentry,
1018 		       const char *content)
1019 {
1020 	struct afs_file_status status;
1021 	struct afs_server *server;
1022 	struct afs_vnode *dvnode, *vnode;
1023 	struct afs_fid fid;
1024 	struct inode *inode;
1025 	struct key *key;
1026 	int ret;
1027 
1028 	dvnode = AFS_FS_I(dir);
1029 
1030 	_enter("{%x:%u},{%pd},%s",
1031 	       dvnode->fid.vid, dvnode->fid.vnode, dentry,
1032 	       content);
1033 
1034 	ret = -EINVAL;
1035 	if (strlen(content) >= AFSPATHMAX)
1036 		goto error;
1037 
1038 	key = afs_request_key(dvnode->volume->cell);
1039 	if (IS_ERR(key)) {
1040 		ret = PTR_ERR(key);
1041 		goto error;
1042 	}
1043 
1044 	ret = afs_vnode_symlink(dvnode, key, dentry->d_name.name, content,
1045 				&fid, &status, &server);
1046 	if (ret < 0)
1047 		goto create_error;
1048 
1049 	inode = afs_iget(dir->i_sb, key, &fid, &status, NULL);
1050 	if (IS_ERR(inode)) {
1051 		/* ENOMEM at a really inconvenient time - just abandon the new
1052 		 * directory on the server */
1053 		ret = PTR_ERR(inode);
1054 		goto iget_error;
1055 	}
1056 
1057 	/* apply the status report we've got for the new vnode */
1058 	vnode = AFS_FS_I(inode);
1059 	spin_lock(&vnode->lock);
1060 	vnode->update_cnt++;
1061 	spin_unlock(&vnode->lock);
1062 	afs_vnode_finalise_status_update(vnode, server);
1063 	afs_put_server(server);
1064 
1065 	d_instantiate(dentry, inode);
1066 	if (d_unhashed(dentry)) {
1067 		_debug("not hashed");
1068 		d_rehash(dentry);
1069 	}
1070 	key_put(key);
1071 	_leave(" = 0");
1072 	return 0;
1073 
1074 iget_error:
1075 	afs_put_server(server);
1076 create_error:
1077 	key_put(key);
1078 error:
1079 	d_drop(dentry);
1080 	_leave(" = %d", ret);
1081 	return ret;
1082 }
1083 
1084 /*
1085  * rename a file in an AFS filesystem and/or move it between directories
1086  */
1087 static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
1088 		      struct inode *new_dir, struct dentry *new_dentry,
1089 		      unsigned int flags)
1090 {
1091 	struct afs_vnode *orig_dvnode, *new_dvnode, *vnode;
1092 	struct key *key;
1093 	int ret;
1094 
1095 	if (flags)
1096 		return -EINVAL;
1097 
1098 	vnode = AFS_FS_I(d_inode(old_dentry));
1099 	orig_dvnode = AFS_FS_I(old_dir);
1100 	new_dvnode = AFS_FS_I(new_dir);
1101 
1102 	_enter("{%x:%u},{%x:%u},{%x:%u},{%pd}",
1103 	       orig_dvnode->fid.vid, orig_dvnode->fid.vnode,
1104 	       vnode->fid.vid, vnode->fid.vnode,
1105 	       new_dvnode->fid.vid, new_dvnode->fid.vnode,
1106 	       new_dentry);
1107 
1108 	key = afs_request_key(orig_dvnode->volume->cell);
1109 	if (IS_ERR(key)) {
1110 		ret = PTR_ERR(key);
1111 		goto error;
1112 	}
1113 
1114 	ret = afs_vnode_rename(orig_dvnode, new_dvnode, key,
1115 			       old_dentry->d_name.name,
1116 			       new_dentry->d_name.name);
1117 	if (ret < 0)
1118 		goto rename_error;
1119 	key_put(key);
1120 	_leave(" = 0");
1121 	return 0;
1122 
1123 rename_error:
1124 	key_put(key);
1125 error:
1126 	d_drop(new_dentry);
1127 	_leave(" = %d", ret);
1128 	return ret;
1129 }
1130