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>
18 #include <linux/smp_lock.h>
21 #include <rxrpc/call.h>
25 static struct dentry *afs_dir_lookup(struct inode *dir, struct dentry *dentry,
26 struct nameidata *nd);
27 static int afs_dir_open(struct inode *inode, struct file *file);
28 static int afs_dir_readdir(struct file *file, void *dirent, filldir_t filldir);
29 static int afs_d_revalidate(struct dentry *dentry, struct nameidata *nd);
30 static int afs_d_delete(struct dentry *dentry);
31 static int afs_dir_lookup_filldir(void *_cookie, const char *name, int nlen,
32 loff_t fpos, u64 ino, unsigned dtype);
34 const struct file_operations afs_dir_file_operations = {
36 .readdir = afs_dir_readdir,
39 const struct inode_operations afs_dir_inode_operations = {
40 .lookup = afs_dir_lookup,
41 .getattr = afs_inode_getattr,
43 .create = afs_dir_create,
45 .unlink = afs_dir_unlink,
46 .symlink = afs_dir_symlink,
47 .mkdir = afs_dir_mkdir,
48 .rmdir = afs_dir_rmdir,
49 .mknod = afs_dir_mknod,
50 .rename = afs_dir_rename,
54 static struct dentry_operations afs_fs_dentry_operations = {
55 .d_revalidate = afs_d_revalidate,
56 .d_delete = afs_d_delete,
59 #define AFS_DIR_HASHTBL_SIZE 128
60 #define AFS_DIR_DIRENT_SIZE 32
61 #define AFS_DIRENT_PER_BLOCK 64
71 uint8_t overflow[4]; /* if any char of the name (inc
72 * NUL) reaches here, consume
73 * the next dirent too */
75 uint8_t extended_name[32];
78 /* AFS directory page header (one at the beginning of every 2048-byte chunk) */
79 struct afs_dir_pagehdr {
82 #define AFS_DIR_MAGIC htons(1234)
88 /* directory block layout */
91 struct afs_dir_pagehdr pagehdr;
94 struct afs_dir_pagehdr pagehdr;
95 uint8_t alloc_ctrs[128];
97 uint16_t hashtable[AFS_DIR_HASHTBL_SIZE];
100 union afs_dirent dirents[AFS_DIRENT_PER_BLOCK];
103 /* layout on a linux VM page */
104 struct afs_dir_page {
105 union afs_dir_block blocks[PAGE_SIZE / sizeof(union afs_dir_block)];
108 struct afs_dir_lookup_cookie {
116 * check that a directory page is valid
118 static inline void afs_dir_check_page(struct inode *dir, struct page *page)
120 struct afs_dir_page *dbuf;
125 /* check the page count */
126 qty = desc.size / sizeof(dbuf->blocks[0]);
130 if (page->index==0 && qty!=ntohs(dbuf->blocks[0].pagehdr.npages)) {
131 printk("kAFS: %s(%lu): wrong number of dir blocks %d!=%hu\n",
132 __FUNCTION__,dir->i_ino,qty,ntohs(dbuf->blocks[0].pagehdr.npages));
137 /* determine how many magic numbers there should be in this page */
138 latter = dir->i_size - page_offset(page);
139 if (latter >= PAGE_SIZE)
143 qty /= sizeof(union afs_dir_block);
146 dbuf = page_address(page);
147 for (tmp = 0; tmp < qty; tmp++) {
148 if (dbuf->blocks[tmp].pagehdr.magic != AFS_DIR_MAGIC) {
149 printk("kAFS: %s(%lu): bad magic %d/%d is %04hx\n",
150 __FUNCTION__, dir->i_ino, tmp, qty,
151 ntohs(dbuf->blocks[tmp].pagehdr.magic));
156 SetPageChecked(page);
160 SetPageChecked(page);
165 * discard a page cached in the pagecache
167 static inline void afs_dir_put_page(struct page *page)
170 page_cache_release(page);
174 * get a page into the pagecache
176 static struct page *afs_dir_get_page(struct inode *dir, unsigned long index)
180 _enter("{%lu},%lu", dir->i_ino, index);
182 page = read_mapping_page(dir->i_mapping, index, NULL);
184 wait_on_page_locked(page);
186 if (!PageUptodate(page))
188 if (!PageChecked(page))
189 afs_dir_check_page(dir, page);
196 afs_dir_put_page(page);
197 return ERR_PTR(-EIO);
201 * open an AFS directory file
203 static int afs_dir_open(struct inode *inode, struct file *file)
205 _enter("{%lu}", inode->i_ino);
207 BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);
208 BUILD_BUG_ON(sizeof(union afs_dirent) != 32);
210 if (AFS_FS_I(inode)->flags & AFS_VNODE_DELETED)
218 * deal with one block in an AFS directory
220 static int afs_dir_iterate_block(unsigned *fpos,
221 union afs_dir_block *block,
226 union afs_dirent *dire;
227 unsigned offset, next, curr;
231 _enter("%u,%x,%p,,",*fpos,blkoff,block);
233 curr = (*fpos - blkoff) / sizeof(union afs_dirent);
235 /* walk through the block, an entry at a time */
236 for (offset = AFS_DIRENT_PER_BLOCK - block->pagehdr.nentries;
237 offset < AFS_DIRENT_PER_BLOCK;
242 /* skip entries marked unused in the bitmap */
243 if (!(block->pagehdr.bitmap[offset / 8] &
244 (1 << (offset % 8)))) {
245 _debug("ENT[%Zu.%u]: unused\n",
246 blkoff / sizeof(union afs_dir_block), offset);
249 next * sizeof(union afs_dirent);
253 /* got a valid entry */
254 dire = &block->dirents[offset];
255 nlen = strnlen(dire->u.name,
257 offset * sizeof(union afs_dirent));
259 _debug("ENT[%Zu.%u]: %s %Zu \"%s\"\n",
260 blkoff / sizeof(union afs_dir_block), offset,
261 (offset < curr ? "skip" : "fill"),
264 /* work out where the next possible entry is */
265 for (tmp = nlen; tmp > 15; tmp -= sizeof(union afs_dirent)) {
266 if (next >= AFS_DIRENT_PER_BLOCK) {
267 _debug("ENT[%Zu.%u]:"
268 " %u travelled beyond end dir block"
270 blkoff / sizeof(union afs_dir_block),
271 offset, next, tmp, nlen);
274 if (!(block->pagehdr.bitmap[next / 8] &
275 (1 << (next % 8)))) {
276 _debug("ENT[%Zu.%u]:"
277 " %u unmarked extension (len %u/%Zu)\n",
278 blkoff / sizeof(union afs_dir_block),
279 offset, next, tmp, nlen);
283 _debug("ENT[%Zu.%u]: ext %u/%Zu\n",
284 blkoff / sizeof(union afs_dir_block),
289 /* skip if starts before the current position */
293 /* found the next entry */
294 ret = filldir(cookie,
297 blkoff + offset * sizeof(union afs_dirent),
298 ntohl(dire->u.vnode),
299 filldir == afs_dir_lookup_filldir ?
300 ntohl(dire->u.unique) : DT_UNKNOWN);
302 _leave(" = 0 [full]");
306 *fpos = blkoff + next * sizeof(union afs_dirent);
309 _leave(" = 1 [more]");
314 * read an AFS directory
316 static int afs_dir_iterate(struct inode *dir, unsigned *fpos, void *cookie,
319 union afs_dir_block *dblock;
320 struct afs_dir_page *dbuf;
322 unsigned blkoff, limit;
325 _enter("{%lu},%u,,", dir->i_ino, *fpos);
327 if (AFS_FS_I(dir)->flags & AFS_VNODE_DELETED) {
328 _leave(" = -ESTALE");
332 /* round the file position up to the next entry boundary */
333 *fpos += sizeof(union afs_dirent) - 1;
334 *fpos &= ~(sizeof(union afs_dirent) - 1);
336 /* walk through the blocks in sequence */
338 while (*fpos < dir->i_size) {
339 blkoff = *fpos & ~(sizeof(union afs_dir_block) - 1);
341 /* fetch the appropriate page from the directory */
342 page = afs_dir_get_page(dir, blkoff / PAGE_SIZE);
348 limit = blkoff & ~(PAGE_SIZE - 1);
350 dbuf = page_address(page);
352 /* deal with the individual blocks stashed on this page */
354 dblock = &dbuf->blocks[(blkoff % PAGE_SIZE) /
355 sizeof(union afs_dir_block)];
356 ret = afs_dir_iterate_block(fpos, dblock, blkoff,
359 afs_dir_put_page(page);
363 blkoff += sizeof(union afs_dir_block);
365 } while (*fpos < dir->i_size && blkoff < limit);
367 afs_dir_put_page(page);
372 _leave(" = %d", ret);
377 * read an AFS directory
379 static int afs_dir_readdir(struct file *file, void *cookie, filldir_t filldir)
384 _enter("{%Ld,{%lu}}", file->f_pos, file->f_path.dentry->d_inode->i_ino);
387 ret = afs_dir_iterate(file->f_path.dentry->d_inode, &fpos, cookie, filldir);
390 _leave(" = %d", ret);
395 * search the directory for a name
396 * - if afs_dir_iterate_block() spots this function, it'll pass the FID
397 * uniquifier through dtype
399 static int afs_dir_lookup_filldir(void *_cookie, const char *name, int nlen,
400 loff_t fpos, u64 ino, unsigned dtype)
402 struct afs_dir_lookup_cookie *cookie = _cookie;
404 _enter("{%s,%Zu},%s,%u,,%lu,%u",
405 cookie->name, cookie->nlen, name, nlen, ino, dtype);
407 if (cookie->nlen != nlen || memcmp(cookie->name, name, nlen) != 0) {
412 cookie->fid.vnode = ino;
413 cookie->fid.unique = dtype;
416 _leave(" = -1 [found]");
421 * look up an entry in a directory
423 static struct dentry *afs_dir_lookup(struct inode *dir, struct dentry *dentry,
424 struct nameidata *nd)
426 struct afs_dir_lookup_cookie cookie;
427 struct afs_super_info *as;
428 struct afs_vnode *vnode;
433 _enter("{%lu},%p{%s}", dir->i_ino, dentry, dentry->d_name.name);
435 /* insanity checks first */
436 BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);
437 BUILD_BUG_ON(sizeof(union afs_dirent) != 32);
439 if (dentry->d_name.len > 255) {
440 _leave(" = -ENAMETOOLONG");
441 return ERR_PTR(-ENAMETOOLONG);
444 vnode = AFS_FS_I(dir);
445 if (vnode->flags & AFS_VNODE_DELETED) {
446 _leave(" = -ESTALE");
447 return ERR_PTR(-ESTALE);
450 as = dir->i_sb->s_fs_info;
452 /* search the directory */
453 cookie.name = dentry->d_name.name;
454 cookie.nlen = dentry->d_name.len;
455 cookie.fid.vid = as->volume->vid;
459 ret = afs_dir_iterate(dir, &fpos, &cookie, afs_dir_lookup_filldir);
461 _leave(" = %d", ret);
467 _leave(" = %d", ret);
471 /* instantiate the dentry */
472 ret = afs_iget(dir->i_sb, &cookie.fid, &inode);
474 _leave(" = %d", ret);
478 dentry->d_op = &afs_fs_dentry_operations;
479 dentry->d_fsdata = (void *) (unsigned long) vnode->status.version;
481 d_add(dentry, inode);
482 _leave(" = 0 { vn=%u u=%u } -> { ino=%lu v=%lu }",
485 dentry->d_inode->i_ino,
486 dentry->d_inode->i_version);
492 * check that a dentry lookup hit has found a valid entry
493 * - NOTE! the hit can be a negative hit too, so we can't assume we have an
495 * (derived from nfs_lookup_revalidate)
497 static int afs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
499 struct afs_dir_lookup_cookie cookie;
500 struct dentry *parent;
501 struct inode *inode, *dir;
505 _enter("{sb=%p n=%s},", dentry->d_sb, dentry->d_name.name);
507 /* lock down the parent dentry so we can peer at it */
508 parent = dget_parent(dentry->d_parent);
510 dir = parent->d_inode;
511 inode = dentry->d_inode;
513 /* handle a negative dentry */
517 /* handle a bad inode */
518 if (is_bad_inode(inode)) {
519 printk("kAFS: afs_d_revalidate: %s/%s has bad inode\n",
520 dentry->d_parent->d_name.name, dentry->d_name.name);
524 /* force a full look up if the parent directory changed since last the
525 * server was consulted
526 * - otherwise this inode must still exist, even if the inode details
527 * themselves have changed
529 if (AFS_FS_I(dir)->flags & AFS_VNODE_CHANGED)
530 afs_vnode_fetch_status(AFS_FS_I(dir));
532 if (AFS_FS_I(dir)->flags & AFS_VNODE_DELETED) {
533 _debug("%s: parent dir deleted", dentry->d_name.name);
537 if (AFS_FS_I(inode)->flags & AFS_VNODE_DELETED) {
538 _debug("%s: file already deleted", dentry->d_name.name);
542 if ((unsigned long) dentry->d_fsdata !=
543 (unsigned long) AFS_FS_I(dir)->status.version) {
544 _debug("%s: parent changed %lu -> %u",
546 (unsigned long) dentry->d_fsdata,
547 (unsigned) AFS_FS_I(dir)->status.version);
549 /* search the directory for this vnode */
550 cookie.name = dentry->d_name.name;
551 cookie.nlen = dentry->d_name.len;
552 cookie.fid.vid = AFS_FS_I(inode)->volume->vid;
556 ret = afs_dir_iterate(dir, &fpos, &cookie,
557 afs_dir_lookup_filldir);
559 _debug("failed to iterate dir %s: %d",
560 parent->d_name.name, ret);
565 _debug("%s: dirent not found", dentry->d_name.name);
569 /* if the vnode ID has changed, then the dirent points to a
571 if (cookie.fid.vnode != AFS_FS_I(inode)->fid.vnode) {
572 _debug("%s: dirent changed", dentry->d_name.name);
576 /* if the vnode ID uniqifier has changed, then the file has
578 if (cookie.fid.unique != AFS_FS_I(inode)->fid.unique) {
579 _debug("%s: file deleted (uq %u -> %u I:%lu)",
582 AFS_FS_I(inode)->fid.unique,
584 spin_lock(&AFS_FS_I(inode)->lock);
585 AFS_FS_I(inode)->flags |= AFS_VNODE_DELETED;
586 spin_unlock(&AFS_FS_I(inode)->lock);
587 invalidate_remote_inode(inode);
592 (void *) (unsigned long) AFS_FS_I(dir)->status.version;
597 _leave(" = 1 [valid]");
600 /* the dirent, if it exists, now points to a different vnode */
602 spin_lock(&dentry->d_lock);
603 dentry->d_flags |= DCACHE_NFSFS_RENAMED;
604 spin_unlock(&dentry->d_lock);
608 /* don't unhash if we have submounts */
609 if (have_submounts(dentry))
613 shrink_dcache_parent(dentry);
615 _debug("dropping dentry %s/%s",
616 dentry->d_parent->d_name.name, dentry->d_name.name);
621 _leave(" = 0 [bad]");
626 * allow the VFS to enquire as to whether a dentry should be unhashed (mustn't
628 * - called from dput() when d_count is going to 0.
629 * - return 1 to request dentry be unhashed, 0 otherwise
631 static int afs_d_delete(struct dentry *dentry)
633 _enter("%s", dentry->d_name.name);
635 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
638 if (dentry->d_inode) {
639 if (AFS_FS_I(dentry->d_inode)->flags & AFS_VNODE_DELETED)
643 _leave(" = 0 [keep]");
647 _leave(" = 1 [zap]");