diff options
Diffstat (limited to 'fs/ubifs/tnc_misc.c')
-rw-r--r-- | fs/ubifs/tnc_misc.c | 500 |
1 files changed, 500 insertions, 0 deletions
diff --git a/fs/ubifs/tnc_misc.c b/fs/ubifs/tnc_misc.c new file mode 100644 index 000000000..d90ee0107 --- /dev/null +++ b/fs/ubifs/tnc_misc.c @@ -0,0 +1,500 @@ +/* + * This file is part of UBIFS. + * + * Copyright (C) 2006-2008 Nokia Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., 51 + * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + * + * Authors: Adrian Hunter + * Artem Bityutskiy (Битюцкий Артём) + */ + +/* + * This file contains miscelanious TNC-related functions shared betweend + * different files. This file does not form any logically separate TNC + * sub-system. The file was created because there is a lot of TNC code and + * putting it all in one file would make that file too big and unreadable. + */ + +#include "ubifs.h" + +/** + * ubifs_tnc_levelorder_next - next TNC tree element in levelorder traversal. + * @c: UBIFS file-system description object + * @zr: root of the subtree to traverse + * @znode: previous znode + * + * This function implements levelorder TNC traversal. The LNC is ignored. + * Returns the next element or %NULL if @znode is already the last one. + */ +struct ubifs_znode *ubifs_tnc_levelorder_next(const struct ubifs_info *c, + struct ubifs_znode *zr, + struct ubifs_znode *znode) +{ + int level, iip, level_search = 0; + struct ubifs_znode *zn; + + ubifs_assert(c, zr); + + if (unlikely(!znode)) + return zr; + + if (unlikely(znode == zr)) { + if (znode->level == 0) + return NULL; + return ubifs_tnc_find_child(zr, 0); + } + + level = znode->level; + + iip = znode->iip; + while (1) { + ubifs_assert(c, znode->level <= zr->level); + + /* + * First walk up until there is a znode with next branch to + * look at. + */ + while (znode->parent != zr && iip >= znode->parent->child_cnt) { + znode = znode->parent; + iip = znode->iip; + } + + if (unlikely(znode->parent == zr && + iip >= znode->parent->child_cnt)) { + /* This level is done, switch to the lower one */ + level -= 1; + if (level_search || level < 0) + /* + * We were already looking for znode at lower + * level ('level_search'). As we are here + * again, it just does not exist. Or all levels + * were finished ('level < 0'). + */ + return NULL; + + level_search = 1; + iip = -1; + znode = ubifs_tnc_find_child(zr, 0); + ubifs_assert(c, znode); + } + + /* Switch to the next index */ + zn = ubifs_tnc_find_child(znode->parent, iip + 1); + if (!zn) { + /* No more children to look at, we have walk up */ + iip = znode->parent->child_cnt; + continue; + } + + /* Walk back down to the level we came from ('level') */ + while (zn->level != level) { + znode = zn; + zn = ubifs_tnc_find_child(zn, 0); + if (!zn) { + /* + * This path is not too deep so it does not + * reach 'level'. Try next path. + */ + iip = znode->iip; + break; + } + } + + if (zn) { + ubifs_assert(c, zn->level >= 0); + return zn; + } + } +} + +/** + * ubifs_search_zbranch - search znode branch. + * @c: UBIFS file-system description object + * @znode: znode to search in + * @key: key to search for + * @n: znode branch slot number is returned here + * + * This is a helper function which search branch with key @key in @znode using + * binary search. The result of the search may be: + * o exact match, then %1 is returned, and the slot number of the branch is + * stored in @n; + * o no exact match, then %0 is returned and the slot number of the left + * closest branch is returned in @n; the slot if all keys in this znode are + * greater than @key, then %-1 is returned in @n. + */ +int ubifs_search_zbranch(const struct ubifs_info *c, + const struct ubifs_znode *znode, + const union ubifs_key *key, int *n) +{ + int beg = 0, end = znode->child_cnt, uninitialized_var(mid); + int uninitialized_var(cmp); + const struct ubifs_zbranch *zbr = &znode->zbranch[0]; + + ubifs_assert(c, end > beg); + + while (end > beg) { + mid = (beg + end) >> 1; + cmp = keys_cmp(c, key, &zbr[mid].key); + if (cmp > 0) + beg = mid + 1; + else if (cmp < 0) + end = mid; + else { + *n = mid; + return 1; + } + } + + *n = end - 1; + + /* The insert point is after *n */ + ubifs_assert(c, *n >= -1 && *n < znode->child_cnt); + if (*n == -1) + ubifs_assert(c, keys_cmp(c, key, &zbr[0].key) < 0); + else + ubifs_assert(c, keys_cmp(c, key, &zbr[*n].key) > 0); + if (*n + 1 < znode->child_cnt) + ubifs_assert(c, keys_cmp(c, key, &zbr[*n + 1].key) < 0); + + return 0; +} + +/** + * ubifs_tnc_postorder_first - find first znode to do postorder tree traversal. + * @znode: znode to start at (root of the sub-tree to traverse) + * + * Find the lowest leftmost znode in a subtree of the TNC tree. The LNC is + * ignored. + */ +struct ubifs_znode *ubifs_tnc_postorder_first(struct ubifs_znode *znode) +{ + if (unlikely(!znode)) + return NULL; + + while (znode->level > 0) { + struct ubifs_znode *child; + + child = ubifs_tnc_find_child(znode, 0); + if (!child) + return znode; + znode = child; + } + + return znode; +} + +/** + * ubifs_tnc_postorder_next - next TNC tree element in postorder traversal. + * @c: UBIFS file-system description object + * @znode: previous znode + * + * This function implements postorder TNC traversal. The LNC is ignored. + * Returns the next element or %NULL if @znode is already the last one. + */ +struct ubifs_znode *ubifs_tnc_postorder_next(const struct ubifs_info *c, + struct ubifs_znode *znode) +{ + struct ubifs_znode *zn; + + ubifs_assert(c, znode); + if (unlikely(!znode->parent)) + return NULL; + + /* Switch to the next index in the parent */ + zn = ubifs_tnc_find_child(znode->parent, znode->iip + 1); + if (!zn) + /* This is in fact the last child, return parent */ + return znode->parent; + + /* Go to the first znode in this new subtree */ + return ubifs_tnc_postorder_first(zn); +} + +/** + * ubifs_destroy_tnc_subtree - destroy all znodes connected to a subtree. + * @c: UBIFS file-system description object + * @znode: znode defining subtree to destroy + * + * This function destroys subtree of the TNC tree. Returns number of clean + * znodes in the subtree. + */ +long ubifs_destroy_tnc_subtree(const struct ubifs_info *c, + struct ubifs_znode *znode) +{ + struct ubifs_znode *zn = ubifs_tnc_postorder_first(znode); + long clean_freed = 0; + int n; + + ubifs_assert(c, zn); + while (1) { + for (n = 0; n < zn->child_cnt; n++) { + if (!zn->zbranch[n].znode) + continue; + + if (zn->level > 0 && + !ubifs_zn_dirty(zn->zbranch[n].znode)) + clean_freed += 1; + + cond_resched(); + kfree(zn->zbranch[n].znode); + } + + if (zn == znode) { + if (!ubifs_zn_dirty(zn)) + clean_freed += 1; + kfree(zn); + return clean_freed; + } + + zn = ubifs_tnc_postorder_next(c, zn); + } +} + +/** + * read_znode - read an indexing node from flash and fill znode. + * @c: UBIFS file-system description object + * @lnum: LEB of the indexing node to read + * @offs: node offset + * @len: node length + * @znode: znode to read to + * + * This function reads an indexing node from the flash media and fills znode + * with the read data. Returns zero in case of success and a negative error + * code in case of failure. The read indexing node is validated and if anything + * is wrong with it, this function prints complaint messages and returns + * %-EINVAL. + */ +static int read_znode(struct ubifs_info *c, int lnum, int offs, int len, + struct ubifs_znode *znode) +{ + int i, err, type, cmp; + struct ubifs_idx_node *idx; + + idx = kmalloc(c->max_idx_node_sz, GFP_NOFS); + if (!idx) + return -ENOMEM; + + err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs); + if (err < 0) { + kfree(idx); + return err; + } + + znode->child_cnt = le16_to_cpu(idx->child_cnt); + znode->level = le16_to_cpu(idx->level); + + dbg_tnc("LEB %d:%d, level %d, %d branch", + lnum, offs, znode->level, znode->child_cnt); + + if (znode->child_cnt > c->fanout || znode->level > UBIFS_MAX_LEVELS) { + ubifs_err(c, "current fanout %d, branch count %d", + c->fanout, znode->child_cnt); + ubifs_err(c, "max levels %d, znode level %d", + UBIFS_MAX_LEVELS, znode->level); + err = 1; + goto out_dump; + } + + for (i = 0; i < znode->child_cnt; i++) { + const struct ubifs_branch *br = ubifs_idx_branch(c, idx, i); + struct ubifs_zbranch *zbr = &znode->zbranch[i]; + + key_read(c, &br->key, &zbr->key); + zbr->lnum = le32_to_cpu(br->lnum); + zbr->offs = le32_to_cpu(br->offs); + zbr->len = le32_to_cpu(br->len); + zbr->znode = NULL; + + /* Validate branch */ + + if (zbr->lnum < c->main_first || + zbr->lnum >= c->leb_cnt || zbr->offs < 0 || + zbr->offs + zbr->len > c->leb_size || zbr->offs & 7) { + ubifs_err(c, "bad branch %d", i); + err = 2; + goto out_dump; + } + + switch (key_type(c, &zbr->key)) { + case UBIFS_INO_KEY: + case UBIFS_DATA_KEY: + case UBIFS_DENT_KEY: + case UBIFS_XENT_KEY: + break; + default: + ubifs_err(c, "bad key type at slot %d: %d", + i, key_type(c, &zbr->key)); + err = 3; + goto out_dump; + } + + if (znode->level) + continue; + + type = key_type(c, &zbr->key); + if (c->ranges[type].max_len == 0) { + if (zbr->len != c->ranges[type].len) { + ubifs_err(c, "bad target node (type %d) length (%d)", + type, zbr->len); + ubifs_err(c, "have to be %d", c->ranges[type].len); + err = 4; + goto out_dump; + } + } else if (zbr->len < c->ranges[type].min_len || + zbr->len > c->ranges[type].max_len) { + ubifs_err(c, "bad target node (type %d) length (%d)", + type, zbr->len); + ubifs_err(c, "have to be in range of %d-%d", + c->ranges[type].min_len, + c->ranges[type].max_len); + err = 5; + goto out_dump; + } + } + + /* + * Ensure that the next key is greater or equivalent to the + * previous one. + */ + for (i = 0; i < znode->child_cnt - 1; i++) { + const union ubifs_key *key1, *key2; + + key1 = &znode->zbranch[i].key; + key2 = &znode->zbranch[i + 1].key; + + cmp = keys_cmp(c, key1, key2); + if (cmp > 0) { + ubifs_err(c, "bad key order (keys %d and %d)", i, i + 1); + err = 6; + goto out_dump; + } else if (cmp == 0 && !is_hash_key(c, key1)) { + /* These can only be keys with colliding hash */ + ubifs_err(c, "keys %d and %d are not hashed but equivalent", + i, i + 1); + err = 7; + goto out_dump; + } + } + + kfree(idx); + return 0; + +out_dump: + ubifs_err(c, "bad indexing node at LEB %d:%d, error %d", lnum, offs, err); + ubifs_dump_node(c, idx); + kfree(idx); + return -EINVAL; +} + +/** + * ubifs_load_znode - load znode to TNC cache. + * @c: UBIFS file-system description object + * @zbr: znode branch + * @parent: znode's parent + * @iip: index in parent + * + * This function loads znode pointed to by @zbr into the TNC cache and + * returns pointer to it in case of success and a negative error code in case + * of failure. + */ +struct ubifs_znode *ubifs_load_znode(struct ubifs_info *c, + struct ubifs_zbranch *zbr, + struct ubifs_znode *parent, int iip) +{ + int err; + struct ubifs_znode *znode; + + ubifs_assert(c, !zbr->znode); + /* + * A slab cache is not presently used for znodes because the znode size + * depends on the fanout which is stored in the superblock. + */ + znode = kzalloc(c->max_znode_sz, GFP_NOFS); + if (!znode) + return ERR_PTR(-ENOMEM); + + err = read_znode(c, zbr->lnum, zbr->offs, zbr->len, znode); + if (err) + goto out; + + atomic_long_inc(&c->clean_zn_cnt); + + /* + * Increment the global clean znode counter as well. It is OK that + * global and per-FS clean znode counters may be inconsistent for some + * short time (because we might be preempted at this point), the global + * one is only used in shrinker. + */ + atomic_long_inc(&ubifs_clean_zn_cnt); + + zbr->znode = znode; + znode->parent = parent; + znode->time = ktime_get_seconds(); + znode->iip = iip; + + return znode; + +out: + kfree(znode); + return ERR_PTR(err); +} + +/** + * ubifs_tnc_read_node - read a leaf node from the flash media. + * @c: UBIFS file-system description object + * @zbr: key and position of the node + * @node: node is returned here + * + * This function reads a node defined by @zbr from the flash media. Returns + * zero in case of success or a negative negative error code in case of + * failure. + */ +int ubifs_tnc_read_node(struct ubifs_info *c, struct ubifs_zbranch *zbr, + void *node) +{ + union ubifs_key key1, *key = &zbr->key; + int err, type = key_type(c, key); + struct ubifs_wbuf *wbuf; + + /* + * 'zbr' has to point to on-flash node. The node may sit in a bud and + * may even be in a write buffer, so we have to take care about this. + */ + wbuf = ubifs_get_wbuf(c, zbr->lnum); + if (wbuf) + err = ubifs_read_node_wbuf(wbuf, node, type, zbr->len, + zbr->lnum, zbr->offs); + else + err = ubifs_read_node(c, node, type, zbr->len, zbr->lnum, + zbr->offs); + + if (err) { + dbg_tnck(key, "key "); + return err; + } + + /* Make sure the key of the read node is correct */ + key_read(c, node + UBIFS_KEY_OFFSET, &key1); + if (!keys_eq(c, key, &key1)) { + ubifs_err(c, "bad key in node at LEB %d:%d", + zbr->lnum, zbr->offs); + dbg_tnck(key, "looked for key "); + dbg_tnck(&key1, "but found node's key "); + ubifs_dump_node(c, node); + return -EINVAL; + } + + return 0; +} |