2 * This file is part of UBIFS.
4 * Copyright (C) 2006-2008 Nokia Corporation.
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 51
17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 * Authors: Adrian Hunter
20 * Artem Bityutskiy (Битюцкий Артём)
24 * This file contains miscelanious TNC-related functions shared betweend
25 * different files. This file does not form any logically separate TNC
26 * sub-system. The file was created because there is a lot of TNC code and
27 * putting it all in one file would make that file too big and unreadable.
33 * ubifs_tnc_levelorder_next - next TNC tree element in levelorder traversal.
34 * @zr: root of the subtree to traverse
35 * @znode: previous znode
37 * This function implements levelorder TNC traversal. The LNC is ignored.
38 * Returns the next element or %NULL if @znode is already the last one.
40 struct ubifs_znode
*ubifs_tnc_levelorder_next(struct ubifs_znode
*zr
,
41 struct ubifs_znode
*znode
)
43 int level
, iip
, level_search
= 0;
44 struct ubifs_znode
*zn
;
51 if (unlikely(znode
== zr
)) {
52 if (znode
->level
== 0)
54 return ubifs_tnc_find_child(zr
, 0);
61 ubifs_assert(znode
->level
<= zr
->level
);
64 * First walk up until there is a znode with next branch to
67 while (znode
->parent
!= zr
&& iip
>= znode
->parent
->child_cnt
) {
68 znode
= znode
->parent
;
72 if (unlikely(znode
->parent
== zr
&&
73 iip
>= znode
->parent
->child_cnt
)) {
74 /* This level is done, switch to the lower one */
76 if (level_search
|| level
< 0)
78 * We were already looking for znode at lower
79 * level ('level_search'). As we are here
80 * again, it just does not exist. Or all levels
81 * were finished ('level < 0').
87 znode
= ubifs_tnc_find_child(zr
, 0);
91 /* Switch to the next index */
92 zn
= ubifs_tnc_find_child(znode
->parent
, iip
+ 1);
94 /* No more children to look at, we have walk up */
95 iip
= znode
->parent
->child_cnt
;
99 /* Walk back down to the level we came from ('level') */
100 while (zn
->level
!= level
) {
102 zn
= ubifs_tnc_find_child(zn
, 0);
105 * This path is not too deep so it does not
106 * reach 'level'. Try next path.
114 ubifs_assert(zn
->level
>= 0);
121 * ubifs_search_zbranch - search znode branch.
122 * @c: UBIFS file-system description object
123 * @znode: znode to search in
124 * @key: key to search for
125 * @n: znode branch slot number is returned here
127 * This is a helper function which search branch with key @key in @znode using
128 * binary search. The result of the search may be:
129 * o exact match, then %1 is returned, and the slot number of the branch is
131 * o no exact match, then %0 is returned and the slot number of the left
132 * closest branch is returned in @n; the slot if all keys in this znode are
133 * greater than @key, then %-1 is returned in @n.
135 int ubifs_search_zbranch(const struct ubifs_info
*c
,
136 const struct ubifs_znode
*znode
,
137 const union ubifs_key
*key
, int *n
)
139 int beg
= 0, end
= znode
->child_cnt
, uninitialized_var(mid
);
140 int uninitialized_var(cmp
);
141 const struct ubifs_zbranch
*zbr
= &znode
->zbranch
[0];
143 ubifs_assert(end
> beg
);
146 mid
= (beg
+ end
) >> 1;
147 cmp
= keys_cmp(c
, key
, &zbr
[mid
].key
);
160 /* The insert point is after *n */
161 ubifs_assert(*n
>= -1 && *n
< znode
->child_cnt
);
163 ubifs_assert(keys_cmp(c
, key
, &zbr
[0].key
) < 0);
165 ubifs_assert(keys_cmp(c
, key
, &zbr
[*n
].key
) > 0);
166 if (*n
+ 1 < znode
->child_cnt
)
167 ubifs_assert(keys_cmp(c
, key
, &zbr
[*n
+ 1].key
) < 0);
173 * ubifs_tnc_postorder_first - find first znode to do postorder tree traversal.
174 * @znode: znode to start at (root of the sub-tree to traverse)
176 * Find the lowest leftmost znode in a subtree of the TNC tree. The LNC is
179 struct ubifs_znode
*ubifs_tnc_postorder_first(struct ubifs_znode
*znode
)
181 if (unlikely(!znode
))
184 while (znode
->level
> 0) {
185 struct ubifs_znode
*child
;
187 child
= ubifs_tnc_find_child(znode
, 0);
197 * ubifs_tnc_postorder_next - next TNC tree element in postorder traversal.
198 * @znode: previous znode
200 * This function implements postorder TNC traversal. The LNC is ignored.
201 * Returns the next element or %NULL if @znode is already the last one.
203 struct ubifs_znode
*ubifs_tnc_postorder_next(struct ubifs_znode
*znode
)
205 struct ubifs_znode
*zn
;
208 if (unlikely(!znode
->parent
))
211 /* Switch to the next index in the parent */
212 zn
= ubifs_tnc_find_child(znode
->parent
, znode
->iip
+ 1);
214 /* This is in fact the last child, return parent */
215 return znode
->parent
;
217 /* Go to the first znode in this new subtree */
218 return ubifs_tnc_postorder_first(zn
);
222 * ubifs_destroy_tnc_subtree - destroy all znodes connected to a subtree.
223 * @znode: znode defining subtree to destroy
225 * This function destroys subtree of the TNC tree. Returns number of clean
226 * znodes in the subtree.
228 long ubifs_destroy_tnc_subtree(struct ubifs_znode
*znode
)
230 struct ubifs_znode
*zn
= ubifs_tnc_postorder_first(znode
);
231 long clean_freed
= 0;
236 for (n
= 0; n
< zn
->child_cnt
; n
++) {
237 if (!zn
->zbranch
[n
].znode
)
241 !ubifs_zn_dirty(zn
->zbranch
[n
].znode
))
245 kfree(zn
->zbranch
[n
].znode
);
249 if (!ubifs_zn_dirty(zn
))
255 zn
= ubifs_tnc_postorder_next(zn
);
260 * read_znode - read an indexing node from flash and fill znode.
261 * @c: UBIFS file-system description object
262 * @lnum: LEB of the indexing node to read
265 * @znode: znode to read to
267 * This function reads an indexing node from the flash media and fills znode
268 * with the read data. Returns zero in case of success and a negative error
269 * code in case of failure. The read indexing node is validated and if anything
270 * is wrong with it, this function prints complaint messages and returns
273 static int read_znode(struct ubifs_info
*c
, int lnum
, int offs
, int len
,
274 struct ubifs_znode
*znode
)
276 int i
, err
, type
, cmp
;
277 struct ubifs_idx_node
*idx
;
279 idx
= kmalloc(c
->max_idx_node_sz
, GFP_NOFS
);
283 err
= ubifs_read_node(c
, idx
, UBIFS_IDX_NODE
, len
, lnum
, offs
);
289 znode
->child_cnt
= le16_to_cpu(idx
->child_cnt
);
290 znode
->level
= le16_to_cpu(idx
->level
);
292 dbg_tnc("LEB %d:%d, level %d, %d branch",
293 lnum
, offs
, znode
->level
, znode
->child_cnt
);
295 if (znode
->child_cnt
> c
->fanout
|| znode
->level
> UBIFS_MAX_LEVELS
) {
296 dbg_err("current fanout %d, branch count %d",
297 c
->fanout
, znode
->child_cnt
);
298 dbg_err("max levels %d, znode level %d",
299 UBIFS_MAX_LEVELS
, znode
->level
);
304 for (i
= 0; i
< znode
->child_cnt
; i
++) {
305 const struct ubifs_branch
*br
= ubifs_idx_branch(c
, idx
, i
);
306 struct ubifs_zbranch
*zbr
= &znode
->zbranch
[i
];
308 key_read(c
, &br
->key
, &zbr
->key
);
309 zbr
->lnum
= le32_to_cpu(br
->lnum
);
310 zbr
->offs
= le32_to_cpu(br
->offs
);
311 zbr
->len
= le32_to_cpu(br
->len
);
314 /* Validate branch */
316 if (zbr
->lnum
< c
->main_first
||
317 zbr
->lnum
>= c
->leb_cnt
|| zbr
->offs
< 0 ||
318 zbr
->offs
+ zbr
->len
> c
->leb_size
|| zbr
->offs
& 7) {
319 dbg_err("bad branch %d", i
);
324 switch (key_type(c
, &zbr
->key
)) {
331 dbg_msg("bad key type at slot %d: %s", i
,
340 type
= key_type(c
, &zbr
->key
);
341 if (c
->ranges
[type
].max_len
== 0) {
342 if (zbr
->len
!= c
->ranges
[type
].len
) {
343 dbg_err("bad target node (type %d) length (%d)",
345 dbg_err("have to be %d", c
->ranges
[type
].len
);
349 } else if (zbr
->len
< c
->ranges
[type
].min_len
||
350 zbr
->len
> c
->ranges
[type
].max_len
) {
351 dbg_err("bad target node (type %d) length (%d)",
353 dbg_err("have to be in range of %d-%d",
354 c
->ranges
[type
].min_len
,
355 c
->ranges
[type
].max_len
);
362 * Ensure that the next key is greater or equivalent to the
365 for (i
= 0; i
< znode
->child_cnt
- 1; i
++) {
366 const union ubifs_key
*key1
, *key2
;
368 key1
= &znode
->zbranch
[i
].key
;
369 key2
= &znode
->zbranch
[i
+ 1].key
;
371 cmp
= keys_cmp(c
, key1
, key2
);
373 dbg_err("bad key order (keys %d and %d)", i
, i
+ 1);
376 } else if (cmp
== 0 && !is_hash_key(c
, key1
)) {
377 /* These can only be keys with colliding hash */
378 dbg_err("keys %d and %d are not hashed but equivalent",
389 ubifs_err("bad indexing node at LEB %d:%d, error %d", lnum
, offs
, err
);
390 dbg_dump_node(c
, idx
);
396 * ubifs_load_znode - load znode to TNC cache.
397 * @c: UBIFS file-system description object
399 * @parent: znode's parent
400 * @iip: index in parent
402 * This function loads znode pointed to by @zbr into the TNC cache and
403 * returns pointer to it in case of success and a negative error code in case
406 struct ubifs_znode
*ubifs_load_znode(struct ubifs_info
*c
,
407 struct ubifs_zbranch
*zbr
,
408 struct ubifs_znode
*parent
, int iip
)
411 struct ubifs_znode
*znode
;
413 ubifs_assert(!zbr
->znode
);
415 * A slab cache is not presently used for znodes because the znode size
416 * depends on the fanout which is stored in the superblock.
418 znode
= kzalloc(c
->max_znode_sz
, GFP_NOFS
);
420 return ERR_PTR(-ENOMEM
);
422 err
= read_znode(c
, zbr
->lnum
, zbr
->offs
, zbr
->len
, znode
);
426 atomic_long_inc(&c
->clean_zn_cnt
);
429 * Increment the global clean znode counter as well. It is OK that
430 * global and per-FS clean znode counters may be inconsistent for some
431 * short time (because we might be preempted at this point), the global
432 * one is only used in shrinker.
434 atomic_long_inc(&ubifs_clean_zn_cnt
);
437 znode
->parent
= parent
;
438 znode
->time
= get_seconds();
449 * ubifs_tnc_read_node - read a leaf node from the flash media.
450 * @c: UBIFS file-system description object
451 * @zbr: key and position of the node
452 * @node: node is returned here
454 * This function reads a node defined by @zbr from the flash media. Returns
455 * zero in case of success or a negative negative error code in case of
458 int ubifs_tnc_read_node(struct ubifs_info
*c
, struct ubifs_zbranch
*zbr
,
461 union ubifs_key key1
, *key
= &zbr
->key
;
462 int err
, type
= key_type(c
, key
);
463 struct ubifs_wbuf
*wbuf
;
466 * 'zbr' has to point to on-flash node. The node may sit in a bud and
467 * may even be in a write buffer, so we have to take care about this.
469 wbuf
= ubifs_get_wbuf(c
, zbr
->lnum
);
471 err
= ubifs_read_node_wbuf(wbuf
, node
, type
, zbr
->len
,
472 zbr
->lnum
, zbr
->offs
);
474 err
= ubifs_read_node(c
, node
, type
, zbr
->len
, zbr
->lnum
,
478 dbg_tnc("key %s", DBGKEY(key
));
482 /* Make sure the key of the read node is correct */
483 key_read(c
, node
+ UBIFS_KEY_OFFSET
, &key1
);
484 if (!keys_eq(c
, key
, &key1
)) {
485 ubifs_err("bad key in node at LEB %d:%d",
486 zbr
->lnum
, zbr
->offs
);
487 dbg_tnc("looked for key %s found node's key %s",
488 DBGKEY(key
), DBGKEY1(&key1
));
489 dbg_dump_node(c
, node
);
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