1 /* dir.c: AFS filesystem directory handling
3 * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
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.
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/slab.h>
17 #include <linux/pagemap.h>
20 static struct dentry *afs_dir_lookup(struct inode *dir, struct dentry *dentry,
21 struct nameidata *nd);
22 static int afs_dir_open(struct inode *inode, struct file *file);
23 static int afs_dir_readdir(struct file *file, void *dirent, filldir_t filldir);
24 static int afs_d_revalidate(struct dentry *dentry, struct nameidata *nd);
25 static int afs_d_delete(struct dentry *dentry);
26 static int afs_dir_lookup_filldir(void *_cookie, const char *name, int nlen,
27 loff_t fpos, u64 ino, unsigned dtype);
29 const struct file_operations afs_dir_file_operations = {
31 .readdir = afs_dir_readdir,
34 const struct inode_operations afs_dir_inode_operations = {
35 .lookup = afs_dir_lookup,
36 .getattr = afs_inode_getattr,
38 .create = afs_dir_create,
40 .unlink = afs_dir_unlink,
41 .symlink = afs_dir_symlink,
42 .mkdir = afs_dir_mkdir,
43 .rmdir = afs_dir_rmdir,
44 .mknod = afs_dir_mknod,
45 .rename = afs_dir_rename,
49 static struct dentry_operations afs_fs_dentry_operations = {
50 .d_revalidate = afs_d_revalidate,
51 .d_delete = afs_d_delete,
54 #define AFS_DIR_HASHTBL_SIZE 128
55 #define AFS_DIR_DIRENT_SIZE 32
56 #define AFS_DIRENT_PER_BLOCK 64
66 uint8_t overflow[4]; /* if any char of the name (inc
67 * NUL) reaches here, consume
68 * the next dirent too */
70 uint8_t extended_name[32];
73 /* AFS directory page header (one at the beginning of every 2048-byte chunk) */
74 struct afs_dir_pagehdr {
77 #define AFS_DIR_MAGIC htons(1234)
83 /* directory block layout */
86 struct afs_dir_pagehdr pagehdr;
89 struct afs_dir_pagehdr pagehdr;
90 uint8_t alloc_ctrs[128];
92 uint16_t hashtable[AFS_DIR_HASHTBL_SIZE];
95 union afs_dirent dirents[AFS_DIRENT_PER_BLOCK];
98 /* layout on a linux VM page */
100 union afs_dir_block blocks[PAGE_SIZE / sizeof(union afs_dir_block)];
103 struct afs_dir_lookup_cookie {
111 * check that a directory page is valid
113 static inline void afs_dir_check_page(struct inode *dir, struct page *page)
115 struct afs_dir_page *dbuf;
120 /* check the page count */
121 qty = desc.size / sizeof(dbuf->blocks[0]);
125 if (page->index == 0 && qty != ntohs(dbuf->blocks[0].pagehdr.npages)) {
126 printk("kAFS: %s(%lu): wrong number of dir blocks %d!=%hu\n",
127 __FUNCTION__, dir->i_ino, qty,
128 ntohs(dbuf->blocks[0].pagehdr.npages));
133 /* determine how many magic numbers there should be in this page */
134 latter = dir->i_size - page_offset(page);
135 if (latter >= PAGE_SIZE)
139 qty /= sizeof(union afs_dir_block);
142 dbuf = page_address(page);
143 for (tmp = 0; tmp < qty; tmp++) {
144 if (dbuf->blocks[tmp].pagehdr.magic != AFS_DIR_MAGIC) {
145 printk("kAFS: %s(%lu): bad magic %d/%d is %04hx\n",
146 __FUNCTION__, dir->i_ino, tmp, qty,
147 ntohs(dbuf->blocks[tmp].pagehdr.magic));
152 SetPageChecked(page);
156 SetPageChecked(page);
161 * discard a page cached in the pagecache
163 static inline void afs_dir_put_page(struct page *page)
166 page_cache_release(page);
170 * get a page into the pagecache
172 static struct page *afs_dir_get_page(struct inode *dir, unsigned long index)
176 _enter("{%lu},%lu", dir->i_ino, index);
178 page = read_mapping_page(dir->i_mapping, index, NULL);
180 wait_on_page_locked(page);
182 if (!PageUptodate(page))
184 if (!PageChecked(page))
185 afs_dir_check_page(dir, page);
192 afs_dir_put_page(page);
194 return ERR_PTR(-EIO);
198 * open an AFS directory file
200 static int afs_dir_open(struct inode *inode, struct file *file)
202 _enter("{%lu}", inode->i_ino);
204 BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);
205 BUILD_BUG_ON(sizeof(union afs_dirent) != 32);
207 if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(inode)->flags))
215 * deal with one block in an AFS directory
217 static int afs_dir_iterate_block(unsigned *fpos,
218 union afs_dir_block *block,
223 union afs_dirent *dire;
224 unsigned offset, next, curr;
228 _enter("%u,%x,%p,,",*fpos,blkoff,block);
230 curr = (*fpos - blkoff) / sizeof(union afs_dirent);
232 /* walk through the block, an entry at a time */
233 for (offset = AFS_DIRENT_PER_BLOCK - block->pagehdr.nentries;
234 offset < AFS_DIRENT_PER_BLOCK;
239 /* skip entries marked unused in the bitmap */
240 if (!(block->pagehdr.bitmap[offset / 8] &
241 (1 << (offset % 8)))) {
242 _debug("ENT[%Zu.%u]: unused",
243 blkoff / sizeof(union afs_dir_block), offset);
246 next * sizeof(union afs_dirent);
250 /* got a valid entry */
251 dire = &block->dirents[offset];
252 nlen = strnlen(dire->u.name,
254 offset * sizeof(union afs_dirent));
256 _debug("ENT[%Zu.%u]: %s %Zu \"%s\"",
257 blkoff / sizeof(union afs_dir_block), offset,
258 (offset < curr ? "skip" : "fill"),
261 /* work out where the next possible entry is */
262 for (tmp = nlen; tmp > 15; tmp -= sizeof(union afs_dirent)) {
263 if (next >= AFS_DIRENT_PER_BLOCK) {
264 _debug("ENT[%Zu.%u]:"
265 " %u travelled beyond end dir block"
267 blkoff / sizeof(union afs_dir_block),
268 offset, next, tmp, nlen);
271 if (!(block->pagehdr.bitmap[next / 8] &
272 (1 << (next % 8)))) {
273 _debug("ENT[%Zu.%u]:"
274 " %u unmarked extension (len %u/%Zu)",
275 blkoff / sizeof(union afs_dir_block),
276 offset, next, tmp, nlen);
280 _debug("ENT[%Zu.%u]: ext %u/%Zu",
281 blkoff / sizeof(union afs_dir_block),
286 /* skip if starts before the current position */
290 /* found the next entry */
291 ret = filldir(cookie,
294 blkoff + offset * sizeof(union afs_dirent),
295 ntohl(dire->u.vnode),
296 filldir == afs_dir_lookup_filldir ?
297 ntohl(dire->u.unique) : DT_UNKNOWN);
299 _leave(" = 0 [full]");
303 *fpos = blkoff + next * sizeof(union afs_dirent);
306 _leave(" = 1 [more]");
311 * iterate through the data blob that lists the contents of an AFS directory
313 static int afs_dir_iterate(struct inode *dir, unsigned *fpos, void *cookie,
316 union afs_dir_block *dblock;
317 struct afs_dir_page *dbuf;
319 unsigned blkoff, limit;
322 _enter("{%lu},%u,,", dir->i_ino, *fpos);
324 if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(dir)->flags)) {
325 _leave(" = -ESTALE");
329 /* round the file position up to the next entry boundary */
330 *fpos += sizeof(union afs_dirent) - 1;
331 *fpos &= ~(sizeof(union afs_dirent) - 1);
333 /* walk through the blocks in sequence */
335 while (*fpos < dir->i_size) {
336 blkoff = *fpos & ~(sizeof(union afs_dir_block) - 1);
338 /* fetch the appropriate page from the directory */
339 page = afs_dir_get_page(dir, blkoff / PAGE_SIZE);
345 limit = blkoff & ~(PAGE_SIZE - 1);
347 dbuf = page_address(page);
349 /* deal with the individual blocks stashed on this page */
351 dblock = &dbuf->blocks[(blkoff % PAGE_SIZE) /
352 sizeof(union afs_dir_block)];
353 ret = afs_dir_iterate_block(fpos, dblock, blkoff,
356 afs_dir_put_page(page);
360 blkoff += sizeof(union afs_dir_block);
362 } while (*fpos < dir->i_size && blkoff < limit);
364 afs_dir_put_page(page);
369 _leave(" = %d", ret);
374 * read an AFS directory
376 static int afs_dir_readdir(struct file *file, void *cookie, filldir_t filldir)
381 _enter("{%Ld,{%lu}}",
382 file->f_pos, file->f_path.dentry->d_inode->i_ino);
385 ret = afs_dir_iterate(file->f_path.dentry->d_inode, &fpos,
389 _leave(" = %d", ret);
394 * search the directory for a name
395 * - if afs_dir_iterate_block() spots this function, it'll pass the FID
396 * uniquifier through dtype
398 static int afs_dir_lookup_filldir(void *_cookie, const char *name, int nlen,
399 loff_t fpos, u64 ino, unsigned dtype)
401 struct afs_dir_lookup_cookie *cookie = _cookie;
403 _enter("{%s,%Zu},%s,%u,,%llu,%u",
404 cookie->name, cookie->nlen, name, nlen, ino, dtype);
406 /* insanity checks first */
407 BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);
408 BUILD_BUG_ON(sizeof(union afs_dirent) != 32);
410 if (cookie->nlen != nlen || memcmp(cookie->name, name, nlen) != 0) {
415 cookie->fid.vnode = ino;
416 cookie->fid.unique = dtype;
419 _leave(" = -1 [found]");
424 * do a lookup in a directory
426 static int afs_do_lookup(struct inode *dir, struct dentry *dentry,
429 struct afs_dir_lookup_cookie cookie;
430 struct afs_super_info *as;
434 _enter("{%lu},%p{%s},", dir->i_ino, dentry, dentry->d_name.name);
436 as = dir->i_sb->s_fs_info;
438 /* search the directory */
439 cookie.name = dentry->d_name.name;
440 cookie.nlen = dentry->d_name.len;
441 cookie.fid.vid = as->volume->vid;
445 ret = afs_dir_iterate(dir, &fpos, &cookie, afs_dir_lookup_filldir);
447 _leave(" = %d [iter]", ret);
453 _leave(" = -ENOENT [not found]");
458 _leave(" = 0 { vn=%u u=%u }", fid->vnode, fid->unique);
463 * look up an entry in a directory
465 static struct dentry *afs_dir_lookup(struct inode *dir, struct dentry *dentry,
466 struct nameidata *nd)
468 struct afs_vnode *vnode;
473 _enter("{%lu},%p{%s}", dir->i_ino, dentry, dentry->d_name.name);
475 if (dentry->d_name.len > 255) {
476 _leave(" = -ENAMETOOLONG");
477 return ERR_PTR(-ENAMETOOLONG);
480 vnode = AFS_FS_I(dir);
481 if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
482 _leave(" = -ESTALE");
483 return ERR_PTR(-ESTALE);
486 ret = afs_do_lookup(dir, dentry, &fid);
488 _leave(" = %d [do]", ret);
492 /* instantiate the dentry */
493 inode = afs_iget(dir->i_sb, &fid);
495 _leave(" = %ld", PTR_ERR(inode));
496 return ERR_PTR(PTR_ERR(inode));
499 dentry->d_op = &afs_fs_dentry_operations;
501 d_add(dentry, inode);
502 _leave(" = 0 { vn=%u u=%u } -> { ino=%lu v=%lu }",
505 dentry->d_inode->i_ino,
506 dentry->d_inode->i_version);
512 * propagate changed and modified flags on a directory to all the children of
513 * that directory as they may indicate that the ACL on the dir has changed,
514 * potentially rendering the child inaccessible or that a file has been deleted
517 static void afs_propagate_dir_changes(struct dentry *dir)
519 struct dentry *child;
522 c = test_bit(AFS_VNODE_CHANGED, &AFS_FS_I(dir->d_inode)->flags);
523 m = test_bit(AFS_VNODE_MODIFIED, &AFS_FS_I(dir->d_inode)->flags);
525 _enter("{%d,%d}", c, m);
527 spin_lock(&dir->d_lock);
529 list_for_each_entry(child, &dir->d_subdirs, d_u.d_child) {
530 if (child->d_inode) {
531 struct afs_vnode *vnode;
533 _debug("tag %s", child->d_name.name);
534 vnode = AFS_FS_I(child->d_inode);
536 set_bit(AFS_VNODE_DIR_CHANGED, &vnode->flags);
538 set_bit(AFS_VNODE_DIR_MODIFIED, &vnode->flags);
542 spin_unlock(&dir->d_lock);
546 * check that a dentry lookup hit has found a valid entry
547 * - NOTE! the hit can be a negative hit too, so we can't assume we have an
549 * - there are several things we need to check
550 * - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
552 * - parent dir metadata changed (security changes)
553 * - dentry data changed (write, truncate)
554 * - dentry metadata changed (security changes)
556 static int afs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
558 struct afs_vnode *vnode;
560 struct dentry *parent;
561 struct inode *inode, *dir;
564 vnode = AFS_FS_I(dentry->d_inode);
566 _enter("{sb=%p n=%s fl=%lx},",
567 dentry->d_sb, dentry->d_name.name, vnode->flags);
569 /* lock down the parent dentry so we can peer at it */
570 parent = dget_parent(dentry);
572 dir = parent->d_inode;
573 inode = dentry->d_inode;
575 /* handle a negative dentry */
579 /* handle a bad inode */
580 if (is_bad_inode(inode)) {
581 printk("kAFS: afs_d_revalidate: %s/%s has bad inode\n",
582 parent->d_name.name, dentry->d_name.name);
586 /* check that this dirent still exists if the directory's contents were
588 if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(dir)->flags)) {
589 _debug("%s: parent dir deleted", dentry->d_name.name);
593 if (test_and_clear_bit(AFS_VNODE_DIR_MODIFIED, &vnode->flags)) {
594 /* rm/rmdir/rename may have occurred */
595 _debug("dir modified");
597 /* search the directory for this vnode */
598 ret = afs_do_lookup(dir, dentry, &fid);
599 if (ret == -ENOENT) {
600 _debug("%s: dirent not found", dentry->d_name.name);
604 _debug("failed to iterate dir %s: %d",
605 parent->d_name.name, ret);
609 /* if the vnode ID has changed, then the dirent points to a
611 if (fid.vnode != vnode->fid.vnode) {
612 _debug("%s: dirent changed [%u != %u]",
613 dentry->d_name.name, fid.vnode,
618 /* if the vnode ID uniqifier has changed, then the file has
620 if (fid.unique != vnode->fid.unique) {
621 _debug("%s: file deleted (uq %u -> %u I:%lu)",
622 dentry->d_name.name, fid.unique,
623 vnode->fid.unique, inode->i_version);
624 spin_lock(&vnode->lock);
625 set_bit(AFS_VNODE_DELETED, &vnode->flags);
626 spin_unlock(&vnode->lock);
627 invalidate_remote_inode(inode);
632 /* if the directory's metadata were changed then the security may be
633 * different and we may no longer have access */
634 mutex_lock(&vnode->cb_broken_lock);
636 if (test_and_clear_bit(AFS_VNODE_DIR_CHANGED, &vnode->flags) ||
637 test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
638 _debug("%s: changed", dentry->d_name.name);
639 set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
640 if (afs_vnode_fetch_status(vnode) < 0) {
641 mutex_unlock(&vnode->cb_broken_lock);
646 if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
647 _debug("%s: file already deleted", dentry->d_name.name);
648 mutex_unlock(&vnode->cb_broken_lock);
652 /* if the vnode's data version number changed then its contents are
654 if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
656 invalidate_remote_inode(inode);
659 if (S_ISDIR(inode->i_mode) &&
660 (test_bit(AFS_VNODE_CHANGED, &vnode->flags) ||
661 test_bit(AFS_VNODE_MODIFIED, &vnode->flags)))
662 afs_propagate_dir_changes(dentry);
664 clear_bit(AFS_VNODE_CHANGED, &vnode->flags);
665 clear_bit(AFS_VNODE_MODIFIED, &vnode->flags);
666 mutex_unlock(&vnode->cb_broken_lock);
670 _leave(" = 1 [valid]");
673 /* the dirent, if it exists, now points to a different vnode */
675 spin_lock(&dentry->d_lock);
676 dentry->d_flags |= DCACHE_NFSFS_RENAMED;
677 spin_unlock(&dentry->d_lock);
681 /* don't unhash if we have submounts */
682 if (have_submounts(dentry))
686 _debug("dropping dentry %s/%s",
687 parent->d_name.name, dentry->d_name.name);
688 shrink_dcache_parent(dentry);
692 _leave(" = 0 [bad]");
697 * allow the VFS to enquire as to whether a dentry should be unhashed (mustn't
699 * - called from dput() when d_count is going to 0.
700 * - return 1 to request dentry be unhashed, 0 otherwise
702 static int afs_d_delete(struct dentry *dentry)
704 _enter("%s", dentry->d_name.name);
706 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
709 if (dentry->d_inode &&
710 test_bit(AFS_VNODE_DELETED, &AFS_FS_I(dentry->d_inode)->flags))
713 _leave(" = 0 [keep]");
717 _leave(" = 1 [zap]");