/**
* 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(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(*n >= -1 && *n < znode->child_cnt);
if (*n == -1)
ubifs_assert(keys_cmp(c, key, &zbr[0].key) < 0);
else
ubifs_assert(keys_cmp(c, key, &zbr[*n].key) > 0);
if (*n + 1 < znode->child_cnt)
ubifs_assert(keys_cmp(c, key, &zbr[*n + 1].key) < 0);
return 0;
}
/**
* dbg_check_old_index - check the old copy of the index.
* @c: UBIFS file-system description object
* @zroot: root of the new index
*
* In order to be able to recover from an unclean unmount, a complete copy of
* the index must exist on flash. This is the "old" index. The commit process
* must write the "new" index to flash without overwriting or destroying any
* part of the old index. This function is run at commit end in order to check
* that the old index does indeed exist completely intact.
*
* This function returns %0 on success and a negative error code on failure.
*/
int dbg_check_old_index(struct ubifs_info *c, struct ubifs_zbranch *zroot)
{
int lnum, offs, len, err = 0, uninitialized_var(last_level), child_cnt;
int first = 1, iip;
struct ubifs_debug_info *d = c->dbg;
union ubifs_key lower_key, upper_key, l_key, u_key;
unsigned long long uninitialized_var(last_sqnum);
struct ubifs_idx_node *idx;
struct list_head list;
struct idx_node *i;
size_t sz;
if (!(ubifs_chk_flags & UBIFS_CHK_OLD_IDX))
goto out;
INIT_LIST_HEAD(&list);
sz = sizeof(struct idx_node) + ubifs_idx_node_sz(c, c->fanout) -
UBIFS_IDX_NODE_SZ;
/* Start at the old zroot */
lnum = d->old_zroot.lnum;
offs = d->old_zroot.offs;
len = d->old_zroot.len;
iip = 0;
/*
* Traverse the index tree preorder depth-first i.e. do a node and then
* its subtrees from left to right.
*/
while (1) {
struct ubifs_branch *br;
/* Get the next index node */
i = kmalloc(sz, GFP_NOFS);
if (!i) {
err = -ENOMEM;
goto out_free;
}
i->iip = iip;
/* Keep the index nodes on our path in a linked list */
list_add_tail(&i->list, &list);
/* Read the index node */
idx = &i->idx;
err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs);
if (err)
goto out_free;
/* Validate index node */
child_cnt = le16_to_cpu(idx->child_cnt);
if (child_cnt < 1 || child_cnt > c->fanout) {
err = 1;
goto out_dump;
}
if (first) {
first = 0;
/* Check root level and sqnum */
if (le16_to_cpu(idx->level) != d->old_zroot_level) {
err = 2;
goto out_dump;
}
if (le64_to_cpu(idx->ch.sqnum) != d->old_zroot_sqnum) {
err = 3;
goto out_dump;
}
/* Set last values as though root had a parent */
last_level = le16_to_cpu(idx->level) + 1;
last_sqnum = le64_to_cpu(idx->ch.sqnum) + 1;
key_read(c, ubifs_idx_key(c, idx), &lower_key);
highest_ino_key(c, &upper_key, INUM_WATERMARK);
}
key_copy(c, &upper_key, &i->upper_key);
if (le16_to_cpu(idx->level) != last_level - 1) {
err = 3;
goto out_dump;
}
/*
* The index is always written bottom up hence a child's sqnum
* is always less than the parents.
*/
if (le64_to_cpu(idx->ch.sqnum) >= last_sqnum) {
err = 4;
goto out_dump;
}
/* Check key range */
key_read(c, ubifs_idx_key(c, idx), &l_key);
br = ubifs_idx_branch(c, idx, child_cnt - 1);
key_read(c, &br->key, &u_key);
if (keys_cmp(c, &lower_key, &l_key) > 0) {
err = 5;
goto out_dump;
}
if (keys_cmp(c, &upper_key, &u_key) < 0) {
err = 6;
goto out_dump;
}
if (keys_cmp(c, &upper_key, &u_key) == 0)
if (!is_hash_key(c, &u_key)) {
err = 7;
goto out_dump;
}
/* Go to next index node */
if (le16_to_cpu(idx->level) == 0) {
/* At the bottom, so go up until can go right */
while (1) {
/* Drop the bottom of the list */
list_del(&i->list);
kfree(i);
/* No more list means we are done */
if (list_empty(&list))
goto out;
/* Look at the new bottom */
i = list_entry(list.prev, struct idx_node,
list);
idx = &i->idx;
/* Can we go right */
if (iip + 1 < le16_to_cpu(idx->child_cnt)) {
iip = iip + 1;
break;
} else
/* Nope, so go up again */
iip = i->iip;
}
} else
/* Go down left */
iip = 0;
/*
* We have the parent in 'idx' and now we set up for reading the
* child pointed to by slot 'iip'.
*/
last_level = le16_to_cpu(idx->level);
last_sqnum = le64_to_cpu(idx->ch.sqnum);
br = ubifs_idx_branch(c, idx, iip);
lnum = le32_to_cpu(br->lnum);
offs = le32_to_cpu(br->offs);
len = le32_to_cpu(br->len);
key_read(c, &br->key, &lower_key);
if (iip + 1 < le16_to_cpu(idx->child_cnt)) {
br = ubifs_idx_branch(c, idx, iip + 1);
key_read(c, &br->key, &upper_key);
} else
key_copy(c, &i->upper_key, &upper_key);
}
/**
* 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) {
dbg_err("current fanout %d, branch count %d",
c->fanout, znode->child_cnt);
dbg_err("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) {
dbg_err("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:
dbg_msg("bad key type at slot %d: %s", i,
DBGKEY(&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) {
dbg_err("bad target node (type %d) length (%d)",
type, zbr->len);
dbg_err("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) {
dbg_err("bad target node (type %d) length (%d)",
type, zbr->len);
dbg_err("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) {
dbg_err("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 */
dbg_err("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("bad indexing node at LEB %d:%d, error %d", lnum, offs, err);
dbg_dump_node(c, idx);
kfree(idx);
return -EINVAL;
}
