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/sched.h>
16 #include <linux/slab.h>
18 #include <linux/pagemap.h>
19 #include <linux/smp_lock.h>
22 #include <rxrpc/call.h>
26 static struct dentry
*afs_dir_lookup(struct inode
*dir
, struct dentry
*dentry
,
27 struct nameidata
*nd
);
28 static int afs_dir_open(struct inode
*inode
, struct file
*file
);
29 static int afs_dir_readdir(struct file
*file
, void *dirent
, filldir_t filldir
);
30 static int afs_d_revalidate(struct dentry
*dentry
, struct nameidata
*nd
);
31 static int afs_d_delete(struct dentry
*dentry
);
32 static int afs_dir_lookup_filldir(void *_cookie
, const char *name
, int nlen
,
33 loff_t fpos
, u64 ino
, unsigned dtype
);
35 const struct file_operations afs_dir_file_operations
= {
37 .readdir
= afs_dir_readdir
,
40 struct inode_operations afs_dir_inode_operations
= {
41 .lookup
= afs_dir_lookup
,
42 .getattr
= afs_inode_getattr
,
44 .create
= afs_dir_create
,
46 .unlink
= afs_dir_unlink
,
47 .symlink
= afs_dir_symlink
,
48 .mkdir
= afs_dir_mkdir
,
49 .rmdir
= afs_dir_rmdir
,
50 .mknod
= afs_dir_mknod
,
51 .rename
= afs_dir_rename
,
55 static struct dentry_operations afs_fs_dentry_operations
= {
56 .d_revalidate
= afs_d_revalidate
,
57 .d_delete
= afs_d_delete
,
60 #define AFS_DIR_HASHTBL_SIZE 128
61 #define AFS_DIR_DIRENT_SIZE 32
62 #define AFS_DIRENT_PER_BLOCK 64
72 uint8_t overflow
[4]; /* if any char of the name (inc
73 * NUL) reaches here, consume
74 * the next dirent too */
76 uint8_t extended_name
[32];
79 /* AFS directory page header (one at the beginning of every 2048-byte chunk) */
80 struct afs_dir_pagehdr
{
83 #define AFS_DIR_MAGIC htons(1234)
89 /* directory block layout */
92 struct afs_dir_pagehdr pagehdr
;
95 struct afs_dir_pagehdr pagehdr
;
96 uint8_t alloc_ctrs
[128];
98 uint16_t hashtable
[AFS_DIR_HASHTBL_SIZE
];
101 union afs_dirent dirents
[AFS_DIRENT_PER_BLOCK
];
104 /* layout on a linux VM page */
105 struct afs_dir_page
{
106 union afs_dir_block blocks
[PAGE_SIZE
/ sizeof(union afs_dir_block
)];
109 struct afs_dir_lookup_cookie
{
116 /*****************************************************************************/
118 * check that a directory page is valid
120 static inline void afs_dir_check_page(struct inode
*dir
, struct page
*page
)
122 struct afs_dir_page
*dbuf
;
127 /* check the page count */
128 qty
= desc
.size
/ sizeof(dbuf
->blocks
[0]);
132 if (page
->index
==0 && qty
!=ntohs(dbuf
->blocks
[0].pagehdr
.npages
)) {
133 printk("kAFS: %s(%lu): wrong number of dir blocks %d!=%hu\n",
134 __FUNCTION__
,dir
->i_ino
,qty
,ntohs(dbuf
->blocks
[0].pagehdr
.npages
));
139 /* determine how many magic numbers there should be in this page */
140 latter
= dir
->i_size
- page_offset(page
);
141 if (latter
>= PAGE_SIZE
)
145 qty
/= sizeof(union afs_dir_block
);
148 dbuf
= page_address(page
);
149 for (tmp
= 0; tmp
< qty
; tmp
++) {
150 if (dbuf
->blocks
[tmp
].pagehdr
.magic
!= AFS_DIR_MAGIC
) {
151 printk("kAFS: %s(%lu): bad magic %d/%d is %04hx\n",
152 __FUNCTION__
, dir
->i_ino
, tmp
, qty
,
153 ntohs(dbuf
->blocks
[tmp
].pagehdr
.magic
));
158 SetPageChecked(page
);
162 SetPageChecked(page
);
165 } /* end afs_dir_check_page() */
167 /*****************************************************************************/
169 * discard a page cached in the pagecache
171 static inline void afs_dir_put_page(struct page
*page
)
174 page_cache_release(page
);
176 } /* end afs_dir_put_page() */
178 /*****************************************************************************/
180 * get a page into the pagecache
182 static struct page
*afs_dir_get_page(struct inode
*dir
, unsigned long index
)
186 _enter("{%lu},%lu", dir
->i_ino
, index
);
188 page
= read_mapping_page(dir
->i_mapping
, index
, NULL
);
190 wait_on_page_locked(page
);
192 if (!PageUptodate(page
))
194 if (!PageChecked(page
))
195 afs_dir_check_page(dir
, page
);
202 afs_dir_put_page(page
);
203 return ERR_PTR(-EIO
);
204 } /* end afs_dir_get_page() */
206 /*****************************************************************************/
208 * open an AFS directory file
210 static int afs_dir_open(struct inode
*inode
, struct file
*file
)
212 _enter("{%lu}", inode
->i_ino
);
214 BUILD_BUG_ON(sizeof(union afs_dir_block
) != 2048);
215 BUILD_BUG_ON(sizeof(union afs_dirent
) != 32);
217 if (AFS_FS_I(inode
)->flags
& AFS_VNODE_DELETED
)
223 } /* end afs_dir_open() */
225 /*****************************************************************************/
227 * deal with one block in an AFS directory
229 static int afs_dir_iterate_block(unsigned *fpos
,
230 union afs_dir_block
*block
,
235 union afs_dirent
*dire
;
236 unsigned offset
, next
, curr
;
240 _enter("%u,%x,%p,,",*fpos
,blkoff
,block
);
242 curr
= (*fpos
- blkoff
) / sizeof(union afs_dirent
);
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
;
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\n",
255 blkoff
/ sizeof(union afs_dir_block
), offset
);
258 next
* sizeof(union afs_dirent
);
262 /* got a valid entry */
263 dire
= &block
->dirents
[offset
];
264 nlen
= strnlen(dire
->u
.name
,
266 offset
* sizeof(union afs_dirent
));
268 _debug("ENT[%Zu.%u]: %s %Zu \"%s\"\n",
269 blkoff
/ sizeof(union afs_dir_block
), offset
,
270 (offset
< curr
? "skip" : "fill"),
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"
279 blkoff
/ sizeof(union afs_dir_block
),
280 offset
, next
, tmp
, nlen
);
283 if (!(block
->pagehdr
.bitmap
[next
/ 8] &
284 (1 << (next
% 8)))) {
285 _debug("ENT[%Zu.%u]:"
286 " %u unmarked extension (len %u/%Zu)\n",
287 blkoff
/ sizeof(union afs_dir_block
),
288 offset
, next
, tmp
, nlen
);
292 _debug("ENT[%Zu.%u]: ext %u/%Zu\n",
293 blkoff
/ sizeof(union afs_dir_block
),
298 /* skip if starts before the current position */
302 /* found the next entry */
303 ret
= filldir(cookie
,
306 blkoff
+ offset
* sizeof(union afs_dirent
),
307 ntohl(dire
->u
.vnode
),
308 filldir
== afs_dir_lookup_filldir
?
309 ntohl(dire
->u
.unique
) : DT_UNKNOWN
);
311 _leave(" = 0 [full]");
315 *fpos
= blkoff
+ next
* sizeof(union afs_dirent
);
318 _leave(" = 1 [more]");
320 } /* end afs_dir_iterate_block() */
322 /*****************************************************************************/
324 * read an AFS directory
326 static int afs_dir_iterate(struct inode
*dir
, unsigned *fpos
, void *cookie
,
329 union afs_dir_block
*dblock
;
330 struct afs_dir_page
*dbuf
;
332 unsigned blkoff
, limit
;
335 _enter("{%lu},%u,,", dir
->i_ino
, *fpos
);
337 if (AFS_FS_I(dir
)->flags
& AFS_VNODE_DELETED
) {
338 _leave(" = -ESTALE");
342 /* round the file position up to the next entry boundary */
343 *fpos
+= sizeof(union afs_dirent
) - 1;
344 *fpos
&= ~(sizeof(union afs_dirent
) - 1);
346 /* walk through the blocks in sequence */
348 while (*fpos
< dir
->i_size
) {
349 blkoff
= *fpos
& ~(sizeof(union afs_dir_block
) - 1);
351 /* fetch the appropriate page from the directory */
352 page
= afs_dir_get_page(dir
, blkoff
/ PAGE_SIZE
);
358 limit
= blkoff
& ~(PAGE_SIZE
- 1);
360 dbuf
= page_address(page
);
362 /* deal with the individual blocks stashed on this page */
364 dblock
= &dbuf
->blocks
[(blkoff
% PAGE_SIZE
) /
365 sizeof(union afs_dir_block
)];
366 ret
= afs_dir_iterate_block(fpos
, dblock
, blkoff
,
369 afs_dir_put_page(page
);
373 blkoff
+= sizeof(union afs_dir_block
);
375 } while (*fpos
< dir
->i_size
&& blkoff
< limit
);
377 afs_dir_put_page(page
);
382 _leave(" = %d", ret
);
384 } /* end afs_dir_iterate() */
386 /*****************************************************************************/
388 * read an AFS directory
390 static int afs_dir_readdir(struct file
*file
, void *cookie
, filldir_t filldir
)
395 _enter("{%Ld,{%lu}}", file
->f_pos
, file
->f_path
.dentry
->d_inode
->i_ino
);
398 ret
= afs_dir_iterate(file
->f_path
.dentry
->d_inode
, &fpos
, cookie
, filldir
);
401 _leave(" = %d", ret
);
403 } /* end afs_dir_readdir() */
405 /*****************************************************************************/
407 * search the directory for a name
408 * - if afs_dir_iterate_block() spots this function, it'll pass the FID
409 * uniquifier through dtype
411 static int afs_dir_lookup_filldir(void *_cookie
, const char *name
, int nlen
,
412 loff_t fpos
, u64 ino
, unsigned dtype
)
414 struct afs_dir_lookup_cookie
*cookie
= _cookie
;
416 _enter("{%s,%Zu},%s,%u,,%lu,%u",
417 cookie
->name
, cookie
->nlen
, name
, nlen
, ino
, dtype
);
419 if (cookie
->nlen
!= nlen
|| memcmp(cookie
->name
, name
, nlen
) != 0) {
424 cookie
->fid
.vnode
= ino
;
425 cookie
->fid
.unique
= dtype
;
428 _leave(" = -1 [found]");
430 } /* end afs_dir_lookup_filldir() */
432 /*****************************************************************************/
434 * look up an entry in a directory
436 static struct dentry
*afs_dir_lookup(struct inode
*dir
, struct dentry
*dentry
,
437 struct nameidata
*nd
)
439 struct afs_dir_lookup_cookie cookie
;
440 struct afs_super_info
*as
;
441 struct afs_vnode
*vnode
;
446 _enter("{%lu},%p{%s}", dir
->i_ino
, dentry
, dentry
->d_name
.name
);
448 /* insanity checks first */
449 BUILD_BUG_ON(sizeof(union afs_dir_block
) != 2048);
450 BUILD_BUG_ON(sizeof(union afs_dirent
) != 32);
452 if (dentry
->d_name
.len
> 255) {
453 _leave(" = -ENAMETOOLONG");
454 return ERR_PTR(-ENAMETOOLONG
);
457 vnode
= AFS_FS_I(dir
);
458 if (vnode
->flags
& AFS_VNODE_DELETED
) {
459 _leave(" = -ESTALE");
460 return ERR_PTR(-ESTALE
);
463 as
= dir
->i_sb
->s_fs_info
;
465 /* search the directory */
466 cookie
.name
= dentry
->d_name
.name
;
467 cookie
.nlen
= dentry
->d_name
.len
;
468 cookie
.fid
.vid
= as
->volume
->vid
;
472 ret
= afs_dir_iterate(dir
, &fpos
, &cookie
, afs_dir_lookup_filldir
);
474 _leave(" = %d", ret
);
480 _leave(" = %d", ret
);
484 /* instantiate the dentry */
485 ret
= afs_iget(dir
->i_sb
, &cookie
.fid
, &inode
);
487 _leave(" = %d", ret
);
491 dentry
->d_op
= &afs_fs_dentry_operations
;
492 dentry
->d_fsdata
= (void *) (unsigned long) vnode
->status
.version
;
494 d_add(dentry
, inode
);
495 _leave(" = 0 { vn=%u u=%u } -> { ino=%lu v=%lu }",
498 dentry
->d_inode
->i_ino
,
499 dentry
->d_inode
->i_version
);
502 } /* end afs_dir_lookup() */
504 /*****************************************************************************/
506 * check that a dentry lookup hit has found a valid entry
507 * - NOTE! the hit can be a negative hit too, so we can't assume we have an
509 * (derived from nfs_lookup_revalidate)
511 static int afs_d_revalidate(struct dentry
*dentry
, struct nameidata
*nd
)
513 struct afs_dir_lookup_cookie cookie
;
514 struct dentry
*parent
;
515 struct inode
*inode
, *dir
;
519 _enter("{sb=%p n=%s},", dentry
->d_sb
, dentry
->d_name
.name
);
521 /* lock down the parent dentry so we can peer at it */
522 parent
= dget_parent(dentry
->d_parent
);
524 dir
= parent
->d_inode
;
525 inode
= dentry
->d_inode
;
527 /* handle a negative dentry */
531 /* handle a bad inode */
532 if (is_bad_inode(inode
)) {
533 printk("kAFS: afs_d_revalidate: %s/%s has bad inode\n",
534 dentry
->d_parent
->d_name
.name
, dentry
->d_name
.name
);
538 /* force a full look up if the parent directory changed since last the
539 * server was consulted
540 * - otherwise this inode must still exist, even if the inode details
541 * themselves have changed
543 if (AFS_FS_I(dir
)->flags
& AFS_VNODE_CHANGED
)
544 afs_vnode_fetch_status(AFS_FS_I(dir
));
546 if (AFS_FS_I(dir
)->flags
& AFS_VNODE_DELETED
) {
547 _debug("%s: parent dir deleted", dentry
->d_name
.name
);
551 if (AFS_FS_I(inode
)->flags
& AFS_VNODE_DELETED
) {
552 _debug("%s: file already deleted", dentry
->d_name
.name
);
556 if ((unsigned long) dentry
->d_fsdata
!=
557 (unsigned long) AFS_FS_I(dir
)->status
.version
) {
558 _debug("%s: parent changed %lu -> %u",
560 (unsigned long) dentry
->d_fsdata
,
561 (unsigned) AFS_FS_I(dir
)->status
.version
);
563 /* search the directory for this vnode */
564 cookie
.name
= dentry
->d_name
.name
;
565 cookie
.nlen
= dentry
->d_name
.len
;
566 cookie
.fid
.vid
= AFS_FS_I(inode
)->volume
->vid
;
570 ret
= afs_dir_iterate(dir
, &fpos
, &cookie
,
571 afs_dir_lookup_filldir
);
573 _debug("failed to iterate dir %s: %d",
574 parent
->d_name
.name
, ret
);
579 _debug("%s: dirent not found", dentry
->d_name
.name
);
583 /* if the vnode ID has changed, then the dirent points to a
585 if (cookie
.fid
.vnode
!= AFS_FS_I(inode
)->fid
.vnode
) {
586 _debug("%s: dirent changed", dentry
->d_name
.name
);
590 /* if the vnode ID uniqifier has changed, then the file has
592 if (cookie
.fid
.unique
!= AFS_FS_I(inode
)->fid
.unique
) {
593 _debug("%s: file deleted (uq %u -> %u I:%lu)",
596 AFS_FS_I(inode
)->fid
.unique
,
598 spin_lock(&AFS_FS_I(inode
)->lock
);
599 AFS_FS_I(inode
)->flags
|= AFS_VNODE_DELETED
;
600 spin_unlock(&AFS_FS_I(inode
)->lock
);
601 invalidate_remote_inode(inode
);
606 (void *) (unsigned long) AFS_FS_I(dir
)->status
.version
;
611 _leave(" = 1 [valid]");
614 /* the dirent, if it exists, now points to a different vnode */
616 spin_lock(&dentry
->d_lock
);
617 dentry
->d_flags
|= DCACHE_NFSFS_RENAMED
;
618 spin_unlock(&dentry
->d_lock
);
622 /* don't unhash if we have submounts */
623 if (have_submounts(dentry
))
627 shrink_dcache_parent(dentry
);
629 _debug("dropping dentry %s/%s",
630 dentry
->d_parent
->d_name
.name
, dentry
->d_name
.name
);
635 _leave(" = 0 [bad]");
637 } /* end afs_d_revalidate() */
639 /*****************************************************************************/
641 * allow the VFS to enquire as to whether a dentry should be unhashed (mustn't
643 * - called from dput() when d_count is going to 0.
644 * - return 1 to request dentry be unhashed, 0 otherwise
646 static int afs_d_delete(struct dentry
*dentry
)
648 _enter("%s", dentry
->d_name
.name
);
650 if (dentry
->d_flags
& DCACHE_NFSFS_RENAMED
)
653 if (dentry
->d_inode
) {
654 if (AFS_FS_I(dentry
->d_inode
)->flags
& AFS_VNODE_DELETED
)
658 _leave(" = 0 [keep]");
662 _leave(" = 1 [zap]");
664 } /* end afs_d_delete() */