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Stefan Roese9eefe2a2009-03-19 15:35:05 +01001/*
2 * This file is part of UBIFS.
3 *
4 * Copyright (C) 2006-2008 Nokia Corporation.
5 *
Heiko Schocherff94bc42014-06-24 10:10:04 +02006 * SPDX-License-Identifier: GPL-2.0+
Stefan Roese9eefe2a2009-03-19 15:35:05 +01007 *
8 * Authors: Adrian Hunter
9 * Artem Bityutskiy (Битюцкий Артём)
10 */
11
12/*
13 * This file contains miscelanious TNC-related functions shared betweend
14 * different files. This file does not form any logically separate TNC
15 * sub-system. The file was created because there is a lot of TNC code and
16 * putting it all in one file would make that file too big and unreadable.
17 */
18
Heiko Schocherff94bc42014-06-24 10:10:04 +020019#ifdef __UBOOT__
20#include <linux/err.h>
21#endif
Stefan Roese9eefe2a2009-03-19 15:35:05 +010022#include "ubifs.h"
23
24/**
25 * ubifs_tnc_levelorder_next - next TNC tree element in levelorder traversal.
26 * @zr: root of the subtree to traverse
27 * @znode: previous znode
28 *
29 * This function implements levelorder TNC traversal. The LNC is ignored.
30 * Returns the next element or %NULL if @znode is already the last one.
31 */
32struct ubifs_znode *ubifs_tnc_levelorder_next(struct ubifs_znode *zr,
33 struct ubifs_znode *znode)
34{
35 int level, iip, level_search = 0;
36 struct ubifs_znode *zn;
37
38 ubifs_assert(zr);
39
40 if (unlikely(!znode))
41 return zr;
42
43 if (unlikely(znode == zr)) {
44 if (znode->level == 0)
45 return NULL;
46 return ubifs_tnc_find_child(zr, 0);
47 }
48
49 level = znode->level;
50
51 iip = znode->iip;
52 while (1) {
53 ubifs_assert(znode->level <= zr->level);
54
55 /*
56 * First walk up until there is a znode with next branch to
57 * look at.
58 */
59 while (znode->parent != zr && iip >= znode->parent->child_cnt) {
60 znode = znode->parent;
61 iip = znode->iip;
62 }
63
64 if (unlikely(znode->parent == zr &&
65 iip >= znode->parent->child_cnt)) {
66 /* This level is done, switch to the lower one */
67 level -= 1;
68 if (level_search || level < 0)
69 /*
70 * We were already looking for znode at lower
71 * level ('level_search'). As we are here
72 * again, it just does not exist. Or all levels
73 * were finished ('level < 0').
74 */
75 return NULL;
76
77 level_search = 1;
78 iip = -1;
79 znode = ubifs_tnc_find_child(zr, 0);
80 ubifs_assert(znode);
81 }
82
83 /* Switch to the next index */
84 zn = ubifs_tnc_find_child(znode->parent, iip + 1);
85 if (!zn) {
86 /* No more children to look at, we have walk up */
87 iip = znode->parent->child_cnt;
88 continue;
89 }
90
91 /* Walk back down to the level we came from ('level') */
92 while (zn->level != level) {
93 znode = zn;
94 zn = ubifs_tnc_find_child(zn, 0);
95 if (!zn) {
96 /*
97 * This path is not too deep so it does not
98 * reach 'level'. Try next path.
99 */
100 iip = znode->iip;
101 break;
102 }
103 }
104
105 if (zn) {
106 ubifs_assert(zn->level >= 0);
107 return zn;
108 }
109 }
110}
111
112/**
113 * ubifs_search_zbranch - search znode branch.
114 * @c: UBIFS file-system description object
115 * @znode: znode to search in
116 * @key: key to search for
117 * @n: znode branch slot number is returned here
118 *
119 * This is a helper function which search branch with key @key in @znode using
120 * binary search. The result of the search may be:
121 * o exact match, then %1 is returned, and the slot number of the branch is
122 * stored in @n;
123 * o no exact match, then %0 is returned and the slot number of the left
124 * closest branch is returned in @n; the slot if all keys in this znode are
125 * greater than @key, then %-1 is returned in @n.
126 */
127int ubifs_search_zbranch(const struct ubifs_info *c,
128 const struct ubifs_znode *znode,
129 const union ubifs_key *key, int *n)
130{
131 int beg = 0, end = znode->child_cnt, uninitialized_var(mid);
132 int uninitialized_var(cmp);
133 const struct ubifs_zbranch *zbr = &znode->zbranch[0];
134
135 ubifs_assert(end > beg);
136
137 while (end > beg) {
138 mid = (beg + end) >> 1;
139 cmp = keys_cmp(c, key, &zbr[mid].key);
140 if (cmp > 0)
141 beg = mid + 1;
142 else if (cmp < 0)
143 end = mid;
144 else {
145 *n = mid;
146 return 1;
147 }
148 }
149
150 *n = end - 1;
151
152 /* The insert point is after *n */
153 ubifs_assert(*n >= -1 && *n < znode->child_cnt);
154 if (*n == -1)
155 ubifs_assert(keys_cmp(c, key, &zbr[0].key) < 0);
156 else
157 ubifs_assert(keys_cmp(c, key, &zbr[*n].key) > 0);
158 if (*n + 1 < znode->child_cnt)
159 ubifs_assert(keys_cmp(c, key, &zbr[*n + 1].key) < 0);
160
161 return 0;
162}
163
164/**
165 * ubifs_tnc_postorder_first - find first znode to do postorder tree traversal.
166 * @znode: znode to start at (root of the sub-tree to traverse)
167 *
168 * Find the lowest leftmost znode in a subtree of the TNC tree. The LNC is
169 * ignored.
170 */
171struct ubifs_znode *ubifs_tnc_postorder_first(struct ubifs_znode *znode)
172{
173 if (unlikely(!znode))
174 return NULL;
175
176 while (znode->level > 0) {
177 struct ubifs_znode *child;
178
179 child = ubifs_tnc_find_child(znode, 0);
180 if (!child)
181 return znode;
182 znode = child;
183 }
184
185 return znode;
186}
187
188/**
189 * ubifs_tnc_postorder_next - next TNC tree element in postorder traversal.
190 * @znode: previous znode
191 *
192 * This function implements postorder TNC traversal. The LNC is ignored.
193 * Returns the next element or %NULL if @znode is already the last one.
194 */
195struct ubifs_znode *ubifs_tnc_postorder_next(struct ubifs_znode *znode)
196{
197 struct ubifs_znode *zn;
198
199 ubifs_assert(znode);
200 if (unlikely(!znode->parent))
201 return NULL;
202
203 /* Switch to the next index in the parent */
204 zn = ubifs_tnc_find_child(znode->parent, znode->iip + 1);
205 if (!zn)
206 /* This is in fact the last child, return parent */
207 return znode->parent;
208
209 /* Go to the first znode in this new subtree */
210 return ubifs_tnc_postorder_first(zn);
211}
212
213/**
Heiko Schocherff94bc42014-06-24 10:10:04 +0200214 * ubifs_destroy_tnc_subtree - destroy all znodes connected to a subtree.
215 * @znode: znode defining subtree to destroy
216 *
217 * This function destroys subtree of the TNC tree. Returns number of clean
218 * znodes in the subtree.
219 */
220long ubifs_destroy_tnc_subtree(struct ubifs_znode *znode)
221{
222 struct ubifs_znode *zn = ubifs_tnc_postorder_first(znode);
223 long clean_freed = 0;
224 int n;
225
226 ubifs_assert(zn);
227 while (1) {
228 for (n = 0; n < zn->child_cnt; n++) {
229 if (!zn->zbranch[n].znode)
230 continue;
231
232 if (zn->level > 0 &&
233 !ubifs_zn_dirty(zn->zbranch[n].znode))
234 clean_freed += 1;
235
236 cond_resched();
237 kfree(zn->zbranch[n].znode);
238 }
239
240 if (zn == znode) {
241 if (!ubifs_zn_dirty(zn))
242 clean_freed += 1;
243 kfree(zn);
244 return clean_freed;
245 }
246
247 zn = ubifs_tnc_postorder_next(zn);
248 }
249}
250
251/**
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100252 * read_znode - read an indexing node from flash and fill znode.
253 * @c: UBIFS file-system description object
254 * @lnum: LEB of the indexing node to read
255 * @offs: node offset
256 * @len: node length
257 * @znode: znode to read to
258 *
259 * This function reads an indexing node from the flash media and fills znode
260 * with the read data. Returns zero in case of success and a negative error
261 * code in case of failure. The read indexing node is validated and if anything
262 * is wrong with it, this function prints complaint messages and returns
263 * %-EINVAL.
264 */
265static int read_znode(struct ubifs_info *c, int lnum, int offs, int len,
266 struct ubifs_znode *znode)
267{
268 int i, err, type, cmp;
269 struct ubifs_idx_node *idx;
270
271 idx = kmalloc(c->max_idx_node_sz, GFP_NOFS);
272 if (!idx)
273 return -ENOMEM;
274
275 err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs);
276 if (err < 0) {
277 kfree(idx);
278 return err;
279 }
280
281 znode->child_cnt = le16_to_cpu(idx->child_cnt);
282 znode->level = le16_to_cpu(idx->level);
283
284 dbg_tnc("LEB %d:%d, level %d, %d branch",
285 lnum, offs, znode->level, znode->child_cnt);
286
287 if (znode->child_cnt > c->fanout || znode->level > UBIFS_MAX_LEVELS) {
Heiko Schocherff94bc42014-06-24 10:10:04 +0200288 ubifs_err("current fanout %d, branch count %d",
289 c->fanout, znode->child_cnt);
290 ubifs_err("max levels %d, znode level %d",
291 UBIFS_MAX_LEVELS, znode->level);
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100292 err = 1;
293 goto out_dump;
294 }
295
296 for (i = 0; i < znode->child_cnt; i++) {
297 const struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);
298 struct ubifs_zbranch *zbr = &znode->zbranch[i];
299
300 key_read(c, &br->key, &zbr->key);
301 zbr->lnum = le32_to_cpu(br->lnum);
302 zbr->offs = le32_to_cpu(br->offs);
303 zbr->len = le32_to_cpu(br->len);
304 zbr->znode = NULL;
305
306 /* Validate branch */
307
308 if (zbr->lnum < c->main_first ||
309 zbr->lnum >= c->leb_cnt || zbr->offs < 0 ||
310 zbr->offs + zbr->len > c->leb_size || zbr->offs & 7) {
Heiko Schocherff94bc42014-06-24 10:10:04 +0200311 ubifs_err("bad branch %d", i);
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100312 err = 2;
313 goto out_dump;
314 }
315
316 switch (key_type(c, &zbr->key)) {
317 case UBIFS_INO_KEY:
318 case UBIFS_DATA_KEY:
319 case UBIFS_DENT_KEY:
320 case UBIFS_XENT_KEY:
321 break;
322 default:
Heiko Schocherff94bc42014-06-24 10:10:04 +0200323 ubifs_err("bad key type at slot %d: %d",
324 i, key_type(c, &zbr->key));
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100325 err = 3;
326 goto out_dump;
327 }
328
329 if (znode->level)
330 continue;
331
332 type = key_type(c, &zbr->key);
333 if (c->ranges[type].max_len == 0) {
334 if (zbr->len != c->ranges[type].len) {
Heiko Schocherff94bc42014-06-24 10:10:04 +0200335 ubifs_err("bad target node (type %d) length (%d)",
336 type, zbr->len);
337 ubifs_err("have to be %d", c->ranges[type].len);
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100338 err = 4;
339 goto out_dump;
340 }
341 } else if (zbr->len < c->ranges[type].min_len ||
342 zbr->len > c->ranges[type].max_len) {
Heiko Schocherff94bc42014-06-24 10:10:04 +0200343 ubifs_err("bad target node (type %d) length (%d)",
344 type, zbr->len);
345 ubifs_err("have to be in range of %d-%d",
346 c->ranges[type].min_len,
347 c->ranges[type].max_len);
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100348 err = 5;
349 goto out_dump;
350 }
351 }
352
353 /*
354 * Ensure that the next key is greater or equivalent to the
355 * previous one.
356 */
357 for (i = 0; i < znode->child_cnt - 1; i++) {
358 const union ubifs_key *key1, *key2;
359
360 key1 = &znode->zbranch[i].key;
361 key2 = &znode->zbranch[i + 1].key;
362
363 cmp = keys_cmp(c, key1, key2);
364 if (cmp > 0) {
Heiko Schocherff94bc42014-06-24 10:10:04 +0200365 ubifs_err("bad key order (keys %d and %d)", i, i + 1);
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100366 err = 6;
367 goto out_dump;
368 } else if (cmp == 0 && !is_hash_key(c, key1)) {
369 /* These can only be keys with colliding hash */
Heiko Schocherff94bc42014-06-24 10:10:04 +0200370 ubifs_err("keys %d and %d are not hashed but equivalent",
371 i, i + 1);
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100372 err = 7;
373 goto out_dump;
374 }
375 }
376
377 kfree(idx);
378 return 0;
379
380out_dump:
381 ubifs_err("bad indexing node at LEB %d:%d, error %d", lnum, offs, err);
Heiko Schocherff94bc42014-06-24 10:10:04 +0200382 ubifs_dump_node(c, idx);
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100383 kfree(idx);
384 return -EINVAL;
385}
386
387/**
388 * ubifs_load_znode - load znode to TNC cache.
389 * @c: UBIFS file-system description object
390 * @zbr: znode branch
391 * @parent: znode's parent
392 * @iip: index in parent
393 *
394 * This function loads znode pointed to by @zbr into the TNC cache and
395 * returns pointer to it in case of success and a negative error code in case
396 * of failure.
397 */
398struct ubifs_znode *ubifs_load_znode(struct ubifs_info *c,
399 struct ubifs_zbranch *zbr,
400 struct ubifs_znode *parent, int iip)
401{
402 int err;
403 struct ubifs_znode *znode;
404
405 ubifs_assert(!zbr->znode);
406 /*
407 * A slab cache is not presently used for znodes because the znode size
408 * depends on the fanout which is stored in the superblock.
409 */
410 znode = kzalloc(c->max_znode_sz, GFP_NOFS);
411 if (!znode)
412 return ERR_PTR(-ENOMEM);
413
414 err = read_znode(c, zbr->lnum, zbr->offs, zbr->len, znode);
415 if (err)
416 goto out;
417
Heiko Schocherff94bc42014-06-24 10:10:04 +0200418 atomic_long_inc(&c->clean_zn_cnt);
419
420 /*
421 * Increment the global clean znode counter as well. It is OK that
422 * global and per-FS clean znode counters may be inconsistent for some
423 * short time (because we might be preempted at this point), the global
424 * one is only used in shrinker.
425 */
426 atomic_long_inc(&ubifs_clean_zn_cnt);
427
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100428 zbr->znode = znode;
429 znode->parent = parent;
430 znode->time = get_seconds();
431 znode->iip = iip;
432
433 return znode;
434
435out:
436 kfree(znode);
437 return ERR_PTR(err);
438}
439
440/**
441 * ubifs_tnc_read_node - read a leaf node from the flash media.
442 * @c: UBIFS file-system description object
443 * @zbr: key and position of the node
444 * @node: node is returned here
445 *
446 * This function reads a node defined by @zbr from the flash media. Returns
447 * zero in case of success or a negative negative error code in case of
448 * failure.
449 */
450int ubifs_tnc_read_node(struct ubifs_info *c, struct ubifs_zbranch *zbr,
451 void *node)
452{
453 union ubifs_key key1, *key = &zbr->key;
454 int err, type = key_type(c, key);
Heiko Schocherff94bc42014-06-24 10:10:04 +0200455 struct ubifs_wbuf *wbuf;
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100456
Heiko Schocherff94bc42014-06-24 10:10:04 +0200457 /*
458 * 'zbr' has to point to on-flash node. The node may sit in a bud and
459 * may even be in a write buffer, so we have to take care about this.
460 */
461 wbuf = ubifs_get_wbuf(c, zbr->lnum);
462 if (wbuf)
463 err = ubifs_read_node_wbuf(wbuf, node, type, zbr->len,
464 zbr->lnum, zbr->offs);
465 else
466 err = ubifs_read_node(c, node, type, zbr->len, zbr->lnum,
467 zbr->offs);
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100468
469 if (err) {
Heiko Schocherff94bc42014-06-24 10:10:04 +0200470 dbg_tnck(key, "key ");
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100471 return err;
472 }
473
474 /* Make sure the key of the read node is correct */
475 key_read(c, node + UBIFS_KEY_OFFSET, &key1);
476 if (!keys_eq(c, key, &key1)) {
477 ubifs_err("bad key in node at LEB %d:%d",
478 zbr->lnum, zbr->offs);
Heiko Schocherff94bc42014-06-24 10:10:04 +0200479 dbg_tnck(key, "looked for key ");
480 dbg_tnck(&key1, "but found node's key ");
481 ubifs_dump_node(c, node);
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100482 return -EINVAL;
483 }
484
485 return 0;
486}