xref: /linux/fs/afs/dir.c (revision c0e297dc61f8d4453e07afbea1fa8d0e67cd4a34)
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 
43 const struct file_operations afs_dir_file_operations = {
44 	.open		= afs_dir_open,
45 	.release	= afs_release,
46 	.iterate	= 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 dir_context ctx;
123 	struct afs_fid	fid;
124 	struct qstr name;
125 	int		found;
126 };
127 
128 /*
129  * check that a directory page is valid
130  */
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  */
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  */
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  */
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  */
231 static int afs_dir_iterate_block(struct dir_context *ctx,
232 				 union afs_dir_block *block,
233 				 unsigned blkoff)
234 {
235 	union afs_dirent *dire;
236 	unsigned offset, next, curr;
237 	size_t nlen;
238 	int tmp;
239 
240 	_enter("%u,%x,%p,,",(unsigned)ctx->pos,blkoff,block);
241 
242 	curr = (ctx->pos - blkoff) / sizeof(union afs_dirent);
243 
244 	/* walk through the block, an entry at a time */
245 	for (offset = AFS_DIRENT_PER_BLOCK - block->pagehdr.nentries;
246 	     offset < AFS_DIRENT_PER_BLOCK;
247 	     offset = next
248 	     ) {
249 		next = offset + 1;
250 
251 		/* skip entries marked unused in the bitmap */
252 		if (!(block->pagehdr.bitmap[offset / 8] &
253 		      (1 << (offset % 8)))) {
254 			_debug("ENT[%Zu.%u]: unused",
255 			       blkoff / sizeof(union afs_dir_block), offset);
256 			if (offset >= curr)
257 				ctx->pos = blkoff +
258 					next * sizeof(union afs_dirent);
259 			continue;
260 		}
261 
262 		/* got a valid entry */
263 		dire = &block->dirents[offset];
264 		nlen = strnlen(dire->u.name,
265 			       sizeof(*block) -
266 			       offset * sizeof(union afs_dirent));
267 
268 		_debug("ENT[%Zu.%u]: %s %Zu \"%s\"",
269 		       blkoff / sizeof(union afs_dir_block), offset,
270 		       (offset < curr ? "skip" : "fill"),
271 		       nlen, dire->u.name);
272 
273 		/* work out where the next possible entry is */
274 		for (tmp = nlen; tmp > 15; tmp -= sizeof(union afs_dirent)) {
275 			if (next >= AFS_DIRENT_PER_BLOCK) {
276 				_debug("ENT[%Zu.%u]:"
277 				       " %u travelled beyond end dir block"
278 				       " (len %u/%Zu)",
279 				       blkoff / sizeof(union afs_dir_block),
280 				       offset, next, tmp, nlen);
281 				return -EIO;
282 			}
283 			if (!(block->pagehdr.bitmap[next / 8] &
284 			      (1 << (next % 8)))) {
285 				_debug("ENT[%Zu.%u]:"
286 				       " %u unmarked extension (len %u/%Zu)",
287 				       blkoff / sizeof(union afs_dir_block),
288 				       offset, next, tmp, nlen);
289 				return -EIO;
290 			}
291 
292 			_debug("ENT[%Zu.%u]: ext %u/%Zu",
293 			       blkoff / sizeof(union afs_dir_block),
294 			       next, tmp, nlen);
295 			next++;
296 		}
297 
298 		/* skip if starts before the current position */
299 		if (offset < curr)
300 			continue;
301 
302 		/* found the next entry */
303 		if (!dir_emit(ctx, dire->u.name, nlen,
304 			      ntohl(dire->u.vnode),
305 			      ctx->actor == afs_lookup_filldir ?
306 			      ntohl(dire->u.unique) : DT_UNKNOWN)) {
307 			_leave(" = 0 [full]");
308 			return 0;
309 		}
310 
311 		ctx->pos = blkoff + next * sizeof(union afs_dirent);
312 	}
313 
314 	_leave(" = 1 [more]");
315 	return 1;
316 }
317 
318 /*
319  * iterate through the data blob that lists the contents of an AFS directory
320  */
321 static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
322 			   struct key *key)
323 {
324 	union afs_dir_block *dblock;
325 	struct afs_dir_page *dbuf;
326 	struct page *page;
327 	unsigned blkoff, limit;
328 	int ret;
329 
330 	_enter("{%lu},%u,,", dir->i_ino, (unsigned)ctx->pos);
331 
332 	if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(dir)->flags)) {
333 		_leave(" = -ESTALE");
334 		return -ESTALE;
335 	}
336 
337 	/* round the file position up to the next entry boundary */
338 	ctx->pos += sizeof(union afs_dirent) - 1;
339 	ctx->pos &= ~(sizeof(union afs_dirent) - 1);
340 
341 	/* walk through the blocks in sequence */
342 	ret = 0;
343 	while (ctx->pos < dir->i_size) {
344 		blkoff = ctx->pos & ~(sizeof(union afs_dir_block) - 1);
345 
346 		/* fetch the appropriate page from the directory */
347 		page = afs_dir_get_page(dir, blkoff / PAGE_SIZE, key);
348 		if (IS_ERR(page)) {
349 			ret = PTR_ERR(page);
350 			break;
351 		}
352 
353 		limit = blkoff & ~(PAGE_SIZE - 1);
354 
355 		dbuf = page_address(page);
356 
357 		/* deal with the individual blocks stashed on this page */
358 		do {
359 			dblock = &dbuf->blocks[(blkoff % PAGE_SIZE) /
360 					       sizeof(union afs_dir_block)];
361 			ret = afs_dir_iterate_block(ctx, dblock, blkoff);
362 			if (ret != 1) {
363 				afs_dir_put_page(page);
364 				goto out;
365 			}
366 
367 			blkoff += sizeof(union afs_dir_block);
368 
369 		} while (ctx->pos < dir->i_size && blkoff < limit);
370 
371 		afs_dir_put_page(page);
372 		ret = 0;
373 	}
374 
375 out:
376 	_leave(" = %d", ret);
377 	return ret;
378 }
379 
380 /*
381  * read an AFS directory
382  */
383 static int afs_readdir(struct file *file, struct dir_context *ctx)
384 {
385 	return afs_dir_iterate(file_inode(file),
386 			      ctx, file->private_data);
387 }
388 
389 /*
390  * search the directory for a name
391  * - if afs_dir_iterate_block() spots this function, it'll pass the FID
392  *   uniquifier through dtype
393  */
394 static int afs_lookup_filldir(struct dir_context *ctx, const char *name,
395 			      int nlen, loff_t fpos, u64 ino, unsigned dtype)
396 {
397 	struct afs_lookup_cookie *cookie =
398 		container_of(ctx, struct afs_lookup_cookie, ctx);
399 
400 	_enter("{%s,%u},%s,%u,,%llu,%u",
401 	       cookie->name.name, cookie->name.len, name, nlen,
402 	       (unsigned long long) ino, dtype);
403 
404 	/* insanity checks first */
405 	BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);
406 	BUILD_BUG_ON(sizeof(union afs_dirent) != 32);
407 
408 	if (cookie->name.len != nlen ||
409 	    memcmp(cookie->name.name, name, nlen) != 0) {
410 		_leave(" = 0 [no]");
411 		return 0;
412 	}
413 
414 	cookie->fid.vnode = ino;
415 	cookie->fid.unique = dtype;
416 	cookie->found = 1;
417 
418 	_leave(" = -1 [found]");
419 	return -1;
420 }
421 
422 /*
423  * do a lookup in a directory
424  * - just returns the FID the dentry name maps to if found
425  */
426 static int afs_do_lookup(struct inode *dir, struct dentry *dentry,
427 			 struct afs_fid *fid, struct key *key)
428 {
429 	struct afs_super_info *as = dir->i_sb->s_fs_info;
430 	struct afs_lookup_cookie cookie = {
431 		.ctx.actor = afs_lookup_filldir,
432 		.name = dentry->d_name,
433 		.fid.vid = as->volume->vid
434 	};
435 	int ret;
436 
437 	_enter("{%lu},%p{%pd},", dir->i_ino, dentry, dentry);
438 
439 	/* search the directory */
440 	ret = afs_dir_iterate(dir, &cookie.ctx, key);
441 	if (ret < 0) {
442 		_leave(" = %d [iter]", ret);
443 		return ret;
444 	}
445 
446 	ret = -ENOENT;
447 	if (!cookie.found) {
448 		_leave(" = -ENOENT [not found]");
449 		return -ENOENT;
450 	}
451 
452 	*fid = cookie.fid;
453 	_leave(" = 0 { vn=%u u=%u }", fid->vnode, fid->unique);
454 	return 0;
455 }
456 
457 /*
458  * Try to auto mount the mountpoint with pseudo directory, if the autocell
459  * operation is setted.
460  */
461 static struct inode *afs_try_auto_mntpt(
462 	int ret, struct dentry *dentry, struct inode *dir, struct key *key,
463 	struct afs_fid *fid)
464 {
465 	const char *devname = dentry->d_name.name;
466 	struct afs_vnode *vnode = AFS_FS_I(dir);
467 	struct inode *inode;
468 
469 	_enter("%d, %p{%pd}, {%x:%u}, %p",
470 	       ret, dentry, dentry, vnode->fid.vid, vnode->fid.vnode, key);
471 
472 	if (ret != -ENOENT ||
473 	    !test_bit(AFS_VNODE_AUTOCELL, &vnode->flags))
474 		goto out;
475 
476 	inode = afs_iget_autocell(dir, devname, strlen(devname), key);
477 	if (IS_ERR(inode)) {
478 		ret = PTR_ERR(inode);
479 		goto out;
480 	}
481 
482 	*fid = AFS_FS_I(inode)->fid;
483 	_leave("= %p", inode);
484 	return inode;
485 
486 out:
487 	_leave("= %d", ret);
488 	return ERR_PTR(ret);
489 }
490 
491 /*
492  * look up an entry in a directory
493  */
494 static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
495 				 unsigned int flags)
496 {
497 	struct afs_vnode *vnode;
498 	struct afs_fid fid;
499 	struct inode *inode;
500 	struct key *key;
501 	int ret;
502 
503 	vnode = AFS_FS_I(dir);
504 
505 	_enter("{%x:%u},%p{%pd},",
506 	       vnode->fid.vid, vnode->fid.vnode, dentry, dentry);
507 
508 	ASSERTCMP(d_inode(dentry), ==, NULL);
509 
510 	if (dentry->d_name.len >= AFSNAMEMAX) {
511 		_leave(" = -ENAMETOOLONG");
512 		return ERR_PTR(-ENAMETOOLONG);
513 	}
514 
515 	if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
516 		_leave(" = -ESTALE");
517 		return ERR_PTR(-ESTALE);
518 	}
519 
520 	key = afs_request_key(vnode->volume->cell);
521 	if (IS_ERR(key)) {
522 		_leave(" = %ld [key]", PTR_ERR(key));
523 		return ERR_CAST(key);
524 	}
525 
526 	ret = afs_validate(vnode, key);
527 	if (ret < 0) {
528 		key_put(key);
529 		_leave(" = %d [val]", ret);
530 		return ERR_PTR(ret);
531 	}
532 
533 	ret = afs_do_lookup(dir, dentry, &fid, key);
534 	if (ret < 0) {
535 		inode = afs_try_auto_mntpt(ret, dentry, dir, key, &fid);
536 		if (!IS_ERR(inode)) {
537 			key_put(key);
538 			goto success;
539 		}
540 
541 		ret = PTR_ERR(inode);
542 		key_put(key);
543 		if (ret == -ENOENT) {
544 			d_add(dentry, NULL);
545 			_leave(" = NULL [negative]");
546 			return NULL;
547 		}
548 		_leave(" = %d [do]", ret);
549 		return ERR_PTR(ret);
550 	}
551 	dentry->d_fsdata = (void *)(unsigned long) vnode->status.data_version;
552 
553 	/* instantiate the dentry */
554 	inode = afs_iget(dir->i_sb, key, &fid, NULL, NULL);
555 	key_put(key);
556 	if (IS_ERR(inode)) {
557 		_leave(" = %ld", PTR_ERR(inode));
558 		return ERR_CAST(inode);
559 	}
560 
561 success:
562 	d_add(dentry, inode);
563 	_leave(" = 0 { vn=%u u=%u } -> { ino=%lu v=%u }",
564 	       fid.vnode,
565 	       fid.unique,
566 	       d_inode(dentry)->i_ino,
567 	       d_inode(dentry)->i_generation);
568 
569 	return NULL;
570 }
571 
572 /*
573  * check that a dentry lookup hit has found a valid entry
574  * - NOTE! the hit can be a negative hit too, so we can't assume we have an
575  *   inode
576  */
577 static int afs_d_revalidate(struct dentry *dentry, unsigned int flags)
578 {
579 	struct afs_vnode *vnode, *dir;
580 	struct afs_fid uninitialized_var(fid);
581 	struct dentry *parent;
582 	struct key *key;
583 	void *dir_version;
584 	int ret;
585 
586 	if (flags & LOOKUP_RCU)
587 		return -ECHILD;
588 
589 	vnode = AFS_FS_I(d_inode(dentry));
590 
591 	if (d_really_is_positive(dentry))
592 		_enter("{v={%x:%u} n=%pd fl=%lx},",
593 		       vnode->fid.vid, vnode->fid.vnode, dentry,
594 		       vnode->flags);
595 	else
596 		_enter("{neg n=%pd}", dentry);
597 
598 	key = afs_request_key(AFS_FS_S(dentry->d_sb)->volume->cell);
599 	if (IS_ERR(key))
600 		key = NULL;
601 
602 	/* lock down the parent dentry so we can peer at it */
603 	parent = dget_parent(dentry);
604 	dir = AFS_FS_I(d_inode(parent));
605 
606 	/* validate the parent directory */
607 	if (test_bit(AFS_VNODE_MODIFIED, &dir->flags))
608 		afs_validate(dir, key);
609 
610 	if (test_bit(AFS_VNODE_DELETED, &dir->flags)) {
611 		_debug("%pd: parent dir deleted", dentry);
612 		goto out_bad;
613 	}
614 
615 	dir_version = (void *) (unsigned long) dir->status.data_version;
616 	if (dentry->d_fsdata == dir_version)
617 		goto out_valid; /* the dir contents are unchanged */
618 
619 	_debug("dir modified");
620 
621 	/* search the directory for this vnode */
622 	ret = afs_do_lookup(&dir->vfs_inode, dentry, &fid, key);
623 	switch (ret) {
624 	case 0:
625 		/* the filename maps to something */
626 		if (d_really_is_negative(dentry))
627 			goto out_bad;
628 		if (is_bad_inode(d_inode(dentry))) {
629 			printk("kAFS: afs_d_revalidate: %pd2 has bad inode\n",
630 			       dentry);
631 			goto out_bad;
632 		}
633 
634 		/* if the vnode ID has changed, then the dirent points to a
635 		 * different file */
636 		if (fid.vnode != vnode->fid.vnode) {
637 			_debug("%pd: dirent changed [%u != %u]",
638 			       dentry, fid.vnode,
639 			       vnode->fid.vnode);
640 			goto not_found;
641 		}
642 
643 		/* if the vnode ID uniqifier has changed, then the file has
644 		 * been deleted and replaced, and the original vnode ID has
645 		 * been reused */
646 		if (fid.unique != vnode->fid.unique) {
647 			_debug("%pd: file deleted (uq %u -> %u I:%u)",
648 			       dentry, fid.unique,
649 			       vnode->fid.unique,
650 			       d_inode(dentry)->i_generation);
651 			spin_lock(&vnode->lock);
652 			set_bit(AFS_VNODE_DELETED, &vnode->flags);
653 			spin_unlock(&vnode->lock);
654 			goto not_found;
655 		}
656 		goto out_valid;
657 
658 	case -ENOENT:
659 		/* the filename is unknown */
660 		_debug("%pd: dirent not found", dentry);
661 		if (d_really_is_positive(dentry))
662 			goto not_found;
663 		goto out_valid;
664 
665 	default:
666 		_debug("failed to iterate dir %pd: %d",
667 		       parent, ret);
668 		goto out_bad;
669 	}
670 
671 out_valid:
672 	dentry->d_fsdata = dir_version;
673 	dput(parent);
674 	key_put(key);
675 	_leave(" = 1 [valid]");
676 	return 1;
677 
678 	/* the dirent, if it exists, now points to a different vnode */
679 not_found:
680 	spin_lock(&dentry->d_lock);
681 	dentry->d_flags |= DCACHE_NFSFS_RENAMED;
682 	spin_unlock(&dentry->d_lock);
683 
684 out_bad:
685 	_debug("dropping dentry %pd2", dentry);
686 	dput(parent);
687 	key_put(key);
688 
689 	_leave(" = 0 [bad]");
690 	return 0;
691 }
692 
693 /*
694  * allow the VFS to enquire as to whether a dentry should be unhashed (mustn't
695  * sleep)
696  * - called from dput() when d_count is going to 0.
697  * - return 1 to request dentry be unhashed, 0 otherwise
698  */
699 static int afs_d_delete(const struct dentry *dentry)
700 {
701 	_enter("%pd", dentry);
702 
703 	if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
704 		goto zap;
705 
706 	if (d_really_is_positive(dentry) &&
707 	    (test_bit(AFS_VNODE_DELETED,   &AFS_FS_I(d_inode(dentry))->flags) ||
708 	     test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(d_inode(dentry))->flags)))
709 		goto zap;
710 
711 	_leave(" = 0 [keep]");
712 	return 0;
713 
714 zap:
715 	_leave(" = 1 [zap]");
716 	return 1;
717 }
718 
719 /*
720  * handle dentry release
721  */
722 static void afs_d_release(struct dentry *dentry)
723 {
724 	_enter("%pd", dentry);
725 }
726 
727 /*
728  * create a directory on an AFS filesystem
729  */
730 static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
731 {
732 	struct afs_file_status status;
733 	struct afs_callback cb;
734 	struct afs_server *server;
735 	struct afs_vnode *dvnode, *vnode;
736 	struct afs_fid fid;
737 	struct inode *inode;
738 	struct key *key;
739 	int ret;
740 
741 	dvnode = AFS_FS_I(dir);
742 
743 	_enter("{%x:%u},{%pd},%ho",
744 	       dvnode->fid.vid, dvnode->fid.vnode, dentry, mode);
745 
746 	key = afs_request_key(dvnode->volume->cell);
747 	if (IS_ERR(key)) {
748 		ret = PTR_ERR(key);
749 		goto error;
750 	}
751 
752 	mode |= S_IFDIR;
753 	ret = afs_vnode_create(dvnode, key, dentry->d_name.name,
754 			       mode, &fid, &status, &cb, &server);
755 	if (ret < 0)
756 		goto mkdir_error;
757 
758 	inode = afs_iget(dir->i_sb, key, &fid, &status, &cb);
759 	if (IS_ERR(inode)) {
760 		/* ENOMEM at a really inconvenient time - just abandon the new
761 		 * directory on the server */
762 		ret = PTR_ERR(inode);
763 		goto iget_error;
764 	}
765 
766 	/* apply the status report we've got for the new vnode */
767 	vnode = AFS_FS_I(inode);
768 	spin_lock(&vnode->lock);
769 	vnode->update_cnt++;
770 	spin_unlock(&vnode->lock);
771 	afs_vnode_finalise_status_update(vnode, server);
772 	afs_put_server(server);
773 
774 	d_instantiate(dentry, inode);
775 	if (d_unhashed(dentry)) {
776 		_debug("not hashed");
777 		d_rehash(dentry);
778 	}
779 	key_put(key);
780 	_leave(" = 0");
781 	return 0;
782 
783 iget_error:
784 	afs_put_server(server);
785 mkdir_error:
786 	key_put(key);
787 error:
788 	d_drop(dentry);
789 	_leave(" = %d", ret);
790 	return ret;
791 }
792 
793 /*
794  * remove a directory from an AFS filesystem
795  */
796 static int afs_rmdir(struct inode *dir, struct dentry *dentry)
797 {
798 	struct afs_vnode *dvnode, *vnode;
799 	struct key *key;
800 	int ret;
801 
802 	dvnode = AFS_FS_I(dir);
803 
804 	_enter("{%x:%u},{%pd}",
805 	       dvnode->fid.vid, dvnode->fid.vnode, dentry);
806 
807 	key = afs_request_key(dvnode->volume->cell);
808 	if (IS_ERR(key)) {
809 		ret = PTR_ERR(key);
810 		goto error;
811 	}
812 
813 	ret = afs_vnode_remove(dvnode, key, dentry->d_name.name, true);
814 	if (ret < 0)
815 		goto rmdir_error;
816 
817 	if (d_really_is_positive(dentry)) {
818 		vnode = AFS_FS_I(d_inode(dentry));
819 		clear_nlink(&vnode->vfs_inode);
820 		set_bit(AFS_VNODE_DELETED, &vnode->flags);
821 		afs_discard_callback_on_delete(vnode);
822 	}
823 
824 	key_put(key);
825 	_leave(" = 0");
826 	return 0;
827 
828 rmdir_error:
829 	key_put(key);
830 error:
831 	_leave(" = %d", ret);
832 	return ret;
833 }
834 
835 /*
836  * remove a file from an AFS filesystem
837  */
838 static int afs_unlink(struct inode *dir, struct dentry *dentry)
839 {
840 	struct afs_vnode *dvnode, *vnode;
841 	struct key *key;
842 	int ret;
843 
844 	dvnode = AFS_FS_I(dir);
845 
846 	_enter("{%x:%u},{%pd}",
847 	       dvnode->fid.vid, dvnode->fid.vnode, dentry);
848 
849 	ret = -ENAMETOOLONG;
850 	if (dentry->d_name.len >= AFSNAMEMAX)
851 		goto error;
852 
853 	key = afs_request_key(dvnode->volume->cell);
854 	if (IS_ERR(key)) {
855 		ret = PTR_ERR(key);
856 		goto error;
857 	}
858 
859 	if (d_really_is_positive(dentry)) {
860 		vnode = AFS_FS_I(d_inode(dentry));
861 
862 		/* make sure we have a callback promise on the victim */
863 		ret = afs_validate(vnode, key);
864 		if (ret < 0)
865 			goto error;
866 	}
867 
868 	ret = afs_vnode_remove(dvnode, key, dentry->d_name.name, false);
869 	if (ret < 0)
870 		goto remove_error;
871 
872 	if (d_really_is_positive(dentry)) {
873 		/* if the file wasn't deleted due to excess hard links, the
874 		 * fileserver will break the callback promise on the file - if
875 		 * it had one - before it returns to us, and if it was deleted,
876 		 * it won't
877 		 *
878 		 * however, if we didn't have a callback promise outstanding,
879 		 * or it was outstanding on a different server, then it won't
880 		 * break it either...
881 		 */
882 		vnode = AFS_FS_I(d_inode(dentry));
883 		if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
884 			_debug("AFS_VNODE_DELETED");
885 		if (test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags))
886 			_debug("AFS_VNODE_CB_BROKEN");
887 		set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
888 		ret = afs_validate(vnode, key);
889 		_debug("nlink %d [val %d]", vnode->vfs_inode.i_nlink, ret);
890 	}
891 
892 	key_put(key);
893 	_leave(" = 0");
894 	return 0;
895 
896 remove_error:
897 	key_put(key);
898 error:
899 	_leave(" = %d", ret);
900 	return ret;
901 }
902 
903 /*
904  * create a regular file on an AFS filesystem
905  */
906 static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
907 		      bool excl)
908 {
909 	struct afs_file_status status;
910 	struct afs_callback cb;
911 	struct afs_server *server;
912 	struct afs_vnode *dvnode, *vnode;
913 	struct afs_fid fid;
914 	struct inode *inode;
915 	struct key *key;
916 	int ret;
917 
918 	dvnode = AFS_FS_I(dir);
919 
920 	_enter("{%x:%u},{%pd},%ho,",
921 	       dvnode->fid.vid, dvnode->fid.vnode, dentry, mode);
922 
923 	key = afs_request_key(dvnode->volume->cell);
924 	if (IS_ERR(key)) {
925 		ret = PTR_ERR(key);
926 		goto error;
927 	}
928 
929 	mode |= S_IFREG;
930 	ret = afs_vnode_create(dvnode, key, dentry->d_name.name,
931 			       mode, &fid, &status, &cb, &server);
932 	if (ret < 0)
933 		goto create_error;
934 
935 	inode = afs_iget(dir->i_sb, key, &fid, &status, &cb);
936 	if (IS_ERR(inode)) {
937 		/* ENOMEM at a really inconvenient time - just abandon the new
938 		 * directory on the server */
939 		ret = PTR_ERR(inode);
940 		goto iget_error;
941 	}
942 
943 	/* apply the status report we've got for the new vnode */
944 	vnode = AFS_FS_I(inode);
945 	spin_lock(&vnode->lock);
946 	vnode->update_cnt++;
947 	spin_unlock(&vnode->lock);
948 	afs_vnode_finalise_status_update(vnode, server);
949 	afs_put_server(server);
950 
951 	d_instantiate(dentry, inode);
952 	if (d_unhashed(dentry)) {
953 		_debug("not hashed");
954 		d_rehash(dentry);
955 	}
956 	key_put(key);
957 	_leave(" = 0");
958 	return 0;
959 
960 iget_error:
961 	afs_put_server(server);
962 create_error:
963 	key_put(key);
964 error:
965 	d_drop(dentry);
966 	_leave(" = %d", ret);
967 	return ret;
968 }
969 
970 /*
971  * create a hard link between files in an AFS filesystem
972  */
973 static int afs_link(struct dentry *from, struct inode *dir,
974 		    struct dentry *dentry)
975 {
976 	struct afs_vnode *dvnode, *vnode;
977 	struct key *key;
978 	int ret;
979 
980 	vnode = AFS_FS_I(d_inode(from));
981 	dvnode = AFS_FS_I(dir);
982 
983 	_enter("{%x:%u},{%x:%u},{%pd}",
984 	       vnode->fid.vid, vnode->fid.vnode,
985 	       dvnode->fid.vid, dvnode->fid.vnode,
986 	       dentry);
987 
988 	key = afs_request_key(dvnode->volume->cell);
989 	if (IS_ERR(key)) {
990 		ret = PTR_ERR(key);
991 		goto error;
992 	}
993 
994 	ret = afs_vnode_link(dvnode, vnode, key, dentry->d_name.name);
995 	if (ret < 0)
996 		goto link_error;
997 
998 	ihold(&vnode->vfs_inode);
999 	d_instantiate(dentry, &vnode->vfs_inode);
1000 	key_put(key);
1001 	_leave(" = 0");
1002 	return 0;
1003 
1004 link_error:
1005 	key_put(key);
1006 error:
1007 	d_drop(dentry);
1008 	_leave(" = %d", ret);
1009 	return ret;
1010 }
1011 
1012 /*
1013  * create a symlink in an AFS filesystem
1014  */
1015 static int afs_symlink(struct inode *dir, struct dentry *dentry,
1016 		       const char *content)
1017 {
1018 	struct afs_file_status status;
1019 	struct afs_server *server;
1020 	struct afs_vnode *dvnode, *vnode;
1021 	struct afs_fid fid;
1022 	struct inode *inode;
1023 	struct key *key;
1024 	int ret;
1025 
1026 	dvnode = AFS_FS_I(dir);
1027 
1028 	_enter("{%x:%u},{%pd},%s",
1029 	       dvnode->fid.vid, dvnode->fid.vnode, dentry,
1030 	       content);
1031 
1032 	ret = -EINVAL;
1033 	if (strlen(content) >= AFSPATHMAX)
1034 		goto error;
1035 
1036 	key = afs_request_key(dvnode->volume->cell);
1037 	if (IS_ERR(key)) {
1038 		ret = PTR_ERR(key);
1039 		goto error;
1040 	}
1041 
1042 	ret = afs_vnode_symlink(dvnode, key, dentry->d_name.name, content,
1043 				&fid, &status, &server);
1044 	if (ret < 0)
1045 		goto create_error;
1046 
1047 	inode = afs_iget(dir->i_sb, key, &fid, &status, NULL);
1048 	if (IS_ERR(inode)) {
1049 		/* ENOMEM at a really inconvenient time - just abandon the new
1050 		 * directory on the server */
1051 		ret = PTR_ERR(inode);
1052 		goto iget_error;
1053 	}
1054 
1055 	/* apply the status report we've got for the new vnode */
1056 	vnode = AFS_FS_I(inode);
1057 	spin_lock(&vnode->lock);
1058 	vnode->update_cnt++;
1059 	spin_unlock(&vnode->lock);
1060 	afs_vnode_finalise_status_update(vnode, server);
1061 	afs_put_server(server);
1062 
1063 	d_instantiate(dentry, inode);
1064 	if (d_unhashed(dentry)) {
1065 		_debug("not hashed");
1066 		d_rehash(dentry);
1067 	}
1068 	key_put(key);
1069 	_leave(" = 0");
1070 	return 0;
1071 
1072 iget_error:
1073 	afs_put_server(server);
1074 create_error:
1075 	key_put(key);
1076 error:
1077 	d_drop(dentry);
1078 	_leave(" = %d", ret);
1079 	return ret;
1080 }
1081 
1082 /*
1083  * rename a file in an AFS filesystem and/or move it between directories
1084  */
1085 static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
1086 		      struct inode *new_dir, struct dentry *new_dentry)
1087 {
1088 	struct afs_vnode *orig_dvnode, *new_dvnode, *vnode;
1089 	struct key *key;
1090 	int ret;
1091 
1092 	vnode = AFS_FS_I(d_inode(old_dentry));
1093 	orig_dvnode = AFS_FS_I(old_dir);
1094 	new_dvnode = AFS_FS_I(new_dir);
1095 
1096 	_enter("{%x:%u},{%x:%u},{%x:%u},{%pd}",
1097 	       orig_dvnode->fid.vid, orig_dvnode->fid.vnode,
1098 	       vnode->fid.vid, vnode->fid.vnode,
1099 	       new_dvnode->fid.vid, new_dvnode->fid.vnode,
1100 	       new_dentry);
1101 
1102 	key = afs_request_key(orig_dvnode->volume->cell);
1103 	if (IS_ERR(key)) {
1104 		ret = PTR_ERR(key);
1105 		goto error;
1106 	}
1107 
1108 	ret = afs_vnode_rename(orig_dvnode, new_dvnode, key,
1109 			       old_dentry->d_name.name,
1110 			       new_dentry->d_name.name);
1111 	if (ret < 0)
1112 		goto rename_error;
1113 	key_put(key);
1114 	_leave(" = 0");
1115 	return 0;
1116 
1117 rename_error:
1118 	key_put(key);
1119 error:
1120 	d_drop(new_dentry);
1121 	_leave(" = %d", ret);
1122 	return ret;
1123 }
1124