// SPDX-License-Identifier: GPL-2.0-only /* * This file is part of UBIFS. * * Copyright (C) 2006-2008 Nokia Corporation. * * Authors: Adrian Hunter * Artem Bityutskiy (Битюцкий Артём)
*/
/* * This file implements TNC (Tree Node Cache) which caches indexing nodes of * the UBIFS B-tree. * * At the moment the locking rules of the TNC tree are quite simple and * straightforward. We just have a mutex and lock it when we traverse the * tree. If a znode is not in memory, we read it from flash while still having * the mutex locked.
*/
/* * Returned codes of 'matches_name()' and 'fallible_matches_name()' functions. * @NAME_LESS: name corresponding to the first argument is less than second * @NAME_MATCHES: names match * @NAME_GREATER: name corresponding to the second argument is greater than * first * @NOT_ON_MEDIA: node referred by zbranch does not exist on the media * * These constants were introduce to improve readability.
*/ enum {
NAME_LESS = 0,
NAME_MATCHES = 1,
NAME_GREATER = 2,
NOT_ON_MEDIA = 3,
};
p = &c->old_idx.rb_node; while (*p) {
parent = *p;
o = rb_entry(parent, struct ubifs_old_idx, rb); if (old_idx->lnum < o->lnum)
p = &(*p)->rb_left; elseif (old_idx->lnum > o->lnum)
p = &(*p)->rb_right; elseif (old_idx->offs < o->offs)
p = &(*p)->rb_left; elseif (old_idx->offs > o->offs)
p = &(*p)->rb_right; else {
ubifs_err(c, "old idx added twice!");
kfree(old_idx); return;
}
}
rb_link_node(&old_idx->rb, parent, p);
rb_insert_color(&old_idx->rb, &c->old_idx);
}
/** * insert_old_idx - record an index node obsoleted since the last commit start. * @c: UBIFS file-system description object * @lnum: LEB number of obsoleted index node * @offs: offset of obsoleted index node * * Returns %0 on success, and a negative error code on failure. * * For recovery, there must always be a complete intact version of the index on * flash at all times. That is called the "old index". It is the index as at the * time of the last successful commit. Many of the index nodes in the old index * may be dirty, but they must not be erased until the next successful commit * (at which point that index becomes the old index). * * That means that the garbage collection and the in-the-gaps method of * committing must be able to determine if an index node is in the old index. * Most of the old index nodes can be found by looking up the TNC using the * 'lookup_znode()' function. However, some of the old index nodes may have * been deleted from the current index or may have been changed so much that * they cannot be easily found. In those cases, an entry is added to an RB-tree. * That is what this function does. The RB-tree is ordered by LEB number and * offset because they uniquely identify the old index node.
*/ staticint insert_old_idx(struct ubifs_info *c, int lnum, int offs)
{ struct ubifs_old_idx *old_idx;
/** * insert_old_idx_znode - record a znode obsoleted since last commit start. * @c: UBIFS file-system description object * @znode: znode of obsoleted index node * * Returns %0 on success, and a negative error code on failure.
*/ int insert_old_idx_znode(struct ubifs_info *c, struct ubifs_znode *znode)
{ if (znode->parent) { struct ubifs_zbranch *zbr;
zbr = &znode->parent->zbranch[znode->iip]; if (zbr->len) return insert_old_idx(c, zbr->lnum, zbr->offs);
} else if (c->zroot.len) return insert_old_idx(c, c->zroot.lnum,
c->zroot.offs); return 0;
}
/** * ins_clr_old_idx_znode - record a znode obsoleted since last commit start. * @c: UBIFS file-system description object * @znode: znode of obsoleted index node * * Returns %0 on success, and a negative error code on failure.
*/ staticint ins_clr_old_idx_znode(struct ubifs_info *c, struct ubifs_znode *znode)
{ int err;
/** * destroy_old_idx - destroy the old_idx RB-tree. * @c: UBIFS file-system description object * * During start commit, the old_idx RB-tree is used to avoid overwriting index * nodes that were in the index last commit but have since been deleted. This * is necessary for recovery i.e. the old index must be kept intact until the * new index is successfully written. The old-idx RB-tree is used for the * in-the-gaps method of writing index nodes and is destroyed every commit.
*/ void destroy_old_idx(struct ubifs_info *c)
{ struct ubifs_old_idx *old_idx, *n;
rbtree_postorder_for_each_entry_safe(old_idx, n, &c->old_idx, rb)
kfree(old_idx);
c->old_idx = RB_ROOT;
}
/** * copy_znode - copy a dirty znode. * @c: UBIFS file-system description object * @znode: znode to copy * * A dirty znode being committed may not be changed, so it is copied.
*/ staticstruct ubifs_znode *copy_znode(struct ubifs_info *c, struct ubifs_znode *znode)
{ struct ubifs_znode *zn;
zn = kmemdup(znode, c->max_znode_sz, GFP_NOFS); if (unlikely(!zn)) return ERR_PTR(-ENOMEM);
/** * add_idx_dirt - add dirt due to a dirty znode. * @c: UBIFS file-system description object * @lnum: LEB number of index node * @dirt: size of index node * * This function updates lprops dirty space and the new size of the index.
*/ staticint add_idx_dirt(struct ubifs_info *c, int lnum, int dirt)
{
c->calc_idx_sz -= ALIGN(dirt, 8); return ubifs_add_dirt(c, lnum, dirt);
}
/** * replace_znode - replace old znode with new znode. * @c: UBIFS file-system description object * @new_zn: new znode * @old_zn: old znode * @zbr: the branch of parent znode * * Replace old znode with new znode in TNC.
*/ staticvoid replace_znode(struct ubifs_info *c, struct ubifs_znode *new_zn, struct ubifs_znode *old_zn, struct ubifs_zbranch *zbr)
{
ubifs_assert(c, !ubifs_zn_obsolete(old_zn));
__set_bit(OBSOLETE_ZNODE, &old_zn->flags);
if (old_zn->level != 0) { int i; constint n = new_zn->child_cnt;
/* The children now have new parent */ for (i = 0; i < n; i++) { struct ubifs_zbranch *child = &new_zn->zbranch[i];
if (child->znode)
child->znode->parent = new_zn;
}
}
/** * dirty_cow_znode - ensure a znode is not being committed. * @c: UBIFS file-system description object * @zbr: branch of znode to check * * Returns dirtied znode on success or negative error code on failure.
*/ staticstruct ubifs_znode *dirty_cow_znode(struct ubifs_info *c, struct ubifs_zbranch *zbr)
{ struct ubifs_znode *znode = zbr->znode; struct ubifs_znode *zn; int err;
if (!ubifs_zn_cow(znode)) { /* znode is not being committed */ if (!test_and_set_bit(DIRTY_ZNODE, &znode->flags)) {
atomic_long_inc(&c->dirty_zn_cnt);
atomic_long_dec(&c->clean_zn_cnt);
atomic_long_dec(&ubifs_clean_zn_cnt);
err = add_idx_dirt(c, zbr->lnum, zbr->len); if (unlikely(err)) return ERR_PTR(err);
} return znode;
}
zn = copy_znode(c, znode); if (IS_ERR(zn)) return zn;
/** * lnc_add - add a leaf node to the leaf node cache. * @c: UBIFS file-system description object * @zbr: zbranch of leaf node * @node: leaf node * * Leaf nodes are non-index nodes directory entry nodes or data nodes. The * purpose of the leaf node cache is to save re-reading the same leaf node over * and over again. Most things are cached by VFS, however the file system must * cache directory entries for readdir and for resolving hash collisions. The * present implementation of the leaf node cache is extremely simple, and * allows for error returns that are not used but that may be needed if a more * complex implementation is created. * * Note, this function does not add the @node object to LNC directly, but * allocates a copy of the object and adds the copy to LNC. The reason for this * is that @node has been allocated outside of the TNC subsystem and will be * used with @c->tnc_mutex unlock upon return from the TNC subsystem. But LNC * may be changed at any time, e.g. freed by the shrinker.
*/ staticint lnc_add(struct ubifs_info *c, struct ubifs_zbranch *zbr, constvoid *node)
{ int err; void *lnc_node; conststruct ubifs_dent_node *dent = node;
lnc_node = kmemdup(node, zbr->len, GFP_NOFS); if (!lnc_node) /* We don't have to have the cache, so no error */ return 0;
zbr->leaf = lnc_node; return 0;
}
/** * lnc_add_directly - add a leaf node to the leaf-node-cache. * @c: UBIFS file-system description object * @zbr: zbranch of leaf node * @node: leaf node * * This function is similar to 'lnc_add()', but it does not create a copy of * @node but inserts @node to TNC directly.
*/ staticint lnc_add_directly(struct ubifs_info *c, struct ubifs_zbranch *zbr, void *node)
{ int err;
/** * lnc_free - remove a leaf node from the leaf node cache. * @zbr: zbranch of leaf node
*/ staticvoid lnc_free(struct ubifs_zbranch *zbr)
{ if (!zbr->leaf) return;
kfree(zbr->leaf);
zbr->leaf = NULL;
}
/** * tnc_read_hashed_node - read a "hashed" leaf node. * @c: UBIFS file-system description object * @zbr: key and position of the node * @node: node is returned here * * This function reads a "hashed" node defined by @zbr from the leaf node cache * (in it is there) or from the hash media, in which case the node is also * added to LNC. Returns zero in case of success or a negative error * code in case of failure.
*/ staticint tnc_read_hashed_node(struct ubifs_info *c, struct ubifs_zbranch *zbr, void *node)
{ int err;
ubifs_assert(c, is_hash_key(c, &zbr->key));
if (zbr->leaf) { /* Read from the leaf node cache */
ubifs_assert(c, zbr->len != 0);
memcpy(node, zbr->leaf, zbr->len); return 0;
}
if (c->replaying) {
err = fallible_read_node(c, &zbr->key, zbr, node); /* * When the node was not found, return -ENOENT, 0 otherwise. * Negative return codes stay as-is.
*/ if (err == 0)
err = -ENOENT; elseif (err == 1)
err = 0;
} else {
err = ubifs_tnc_read_node(c, zbr, node);
} if (err) return err;
/* Add the node to the leaf node cache */
err = lnc_add(c, zbr, node); return err;
}
/** * try_read_node - read a node if it is a node. * @c: UBIFS file-system description object * @buf: buffer to read to * @type: node type * @zbr: the zbranch describing the node to read * * This function tries to read a node of known type and length, checks it and * stores it in @buf. This function returns %1 if a node is present and %0 if * a node is not present. A negative error code is returned for I/O errors. * This function performs that same function as ubifs_read_node except that * it does not require that there is actually a node present and instead * the return code indicates if a node was read. * * Note, this function does not check CRC of data nodes if @c->no_chk_data_crc * is true (it is controlled by corresponding mount option). However, if * @c->mounting or @c->remounting_rw is true (we are mounting or re-mounting to * R/W mode), @c->no_chk_data_crc is ignored and CRC is checked. This is * because during mounting or re-mounting from R/O mode to R/W mode we may read * journal nodes (when replying the journal or doing the recovery) and the * journal nodes may potentially be corrupted, so checking is required.
*/ staticint try_read_node(conststruct ubifs_info *c, void *buf, int type, struct ubifs_zbranch *zbr)
{ int len = zbr->len; int lnum = zbr->lnum; int offs = zbr->offs; int err, node_len; struct ubifs_ch *ch = buf;
uint32_t crc, node_crc;
/** * fallible_read_node - try to read a leaf node. * @c: UBIFS file-system description object * @key: key of node to read * @zbr: position of node * @node: node returned * * This function tries to read a node and returns %1 if the node is read, %0 * if the node is not present, and a negative error code in the case of error.
*/ staticint fallible_read_node(struct ubifs_info *c, constunion ubifs_key *key, struct ubifs_zbranch *zbr, void *node)
{ int ret;
ret = try_read_node(c, node, key_type(c, key), zbr); if (ret == 1) { union ubifs_key node_key; struct ubifs_dent_node *dent = node;
/* All nodes have key in the same place */
key_read(c, &dent->key, &node_key); if (keys_cmp(c, key, &node_key) != 0)
ret = 0;
} if (ret == 0 && c->replaying)
dbg_mntk(key, "dangling branch LEB %d:%d len %d, key ",
zbr->lnum, zbr->offs, zbr->len); return ret;
}
/** * matches_name - determine if a direntry or xattr entry matches a given name. * @c: UBIFS file-system description object * @zbr: zbranch of dent * @nm: name to match * * This function checks if xentry/direntry referred by zbranch @zbr matches name * @nm. Returns %NAME_MATCHES if it does, %NAME_LESS if the name referred by * @zbr is less than @nm, and %NAME_GREATER if it is greater than @nm. In case * of failure, a negative error code is returned.
*/ staticint matches_name(struct ubifs_info *c, struct ubifs_zbranch *zbr, conststruct fscrypt_name *nm)
{ struct ubifs_dent_node *dent; int nlen, err;
/* If possible, match against the dent in the leaf node cache */ if (!zbr->leaf) {
dent = kmalloc(zbr->len, GFP_NOFS); if (!dent) return -ENOMEM;
err = ubifs_tnc_read_node(c, zbr, dent); if (err) goto out_free;
/* Add the node to the leaf node cache */
err = lnc_add_directly(c, zbr, dent); if (err) goto out_free;
} else
dent = zbr->leaf;
/** * get_znode - get a TNC znode that may not be loaded yet. * @c: UBIFS file-system description object * @znode: parent znode * @n: znode branch slot number * * This function returns the znode or a negative error code.
*/ staticstruct ubifs_znode *get_znode(struct ubifs_info *c, struct ubifs_znode *znode, int n)
{ struct ubifs_zbranch *zbr;
/** * tnc_next - find next TNC entry. * @c: UBIFS file-system description object * @zn: znode is passed and returned here * @n: znode branch slot number is passed and returned here * * This function returns %0 if the next TNC entry is found, %-ENOENT if there is * no next entry, or a negative error code otherwise.
*/ staticint tnc_next(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
{ struct ubifs_znode *znode = *zn; int nn = *n;
nn += 1; if (nn < znode->child_cnt) {
*n = nn; return 0;
} while (1) { struct ubifs_znode *zp;
zp = znode->parent; if (!zp) return -ENOENT;
nn = znode->iip + 1;
znode = zp; if (nn < znode->child_cnt) {
znode = get_znode(c, znode, nn); if (IS_ERR(znode)) return PTR_ERR(znode); while (znode->level != 0) {
znode = get_znode(c, znode, 0); if (IS_ERR(znode)) return PTR_ERR(znode);
}
nn = 0; break;
}
}
*zn = znode;
*n = nn; return 0;
}
/** * tnc_prev - find previous TNC entry. * @c: UBIFS file-system description object * @zn: znode is returned here * @n: znode branch slot number is passed and returned here * * This function returns %0 if the previous TNC entry is found, %-ENOENT if * there is no next entry, or a negative error code otherwise.
*/ staticint tnc_prev(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
{ struct ubifs_znode *znode = *zn; int nn = *n;
if (nn > 0) {
*n = nn - 1; return 0;
} while (1) { struct ubifs_znode *zp;
zp = znode->parent; if (!zp) return -ENOENT;
nn = znode->iip - 1;
znode = zp; if (nn >= 0) {
znode = get_znode(c, znode, nn); if (IS_ERR(znode)) return PTR_ERR(znode); while (znode->level != 0) {
nn = znode->child_cnt - 1;
znode = get_znode(c, znode, nn); if (IS_ERR(znode)) return PTR_ERR(znode);
}
nn = znode->child_cnt - 1; break;
}
}
*zn = znode;
*n = nn; return 0;
}
/** * resolve_collision - resolve a collision. * @c: UBIFS file-system description object * @key: key of a directory or extended attribute entry * @zn: znode is returned here * @n: zbranch number is passed and returned here * @nm: name of the entry * * This function is called for "hashed" keys to make sure that the found key * really corresponds to the looked up node (directory or extended attribute * entry). It returns %1 and sets @zn and @n if the collision is resolved. * %0 is returned if @nm is not found and @zn and @n are set to the previous * entry, i.e. to the entry after which @nm could follow if it were in TNC. * This means that @n may be set to %-1 if the leftmost key in @zn is the * previous one. A negative error code is returned on failures.
*/ staticint resolve_collision(struct ubifs_info *c, constunion ubifs_key *key, struct ubifs_znode **zn, int *n, conststruct fscrypt_name *nm)
{ int err;
err = matches_name(c, &(*zn)->zbranch[*n], nm); if (unlikely(err < 0)) return err; if (err == NAME_MATCHES) return 1;
if (err == NAME_GREATER) { /* Look left */ while (1) {
err = tnc_prev(c, zn, n); if (err == -ENOENT) {
ubifs_assert(c, *n == 0);
*n = -1; return 0;
} if (err < 0) return err; if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) { /* * We have found the branch after which we would * like to insert, but inserting in this znode * may still be wrong. Consider the following 3 * znodes, in the case where we are resolving a * collision with Key2. * * znode zp * ---------------------- * level 1 | Key0 | Key1 | * ----------------------- * | | * znode za | | znode zb * ------------ ------------ * level 0 | Key0 | | Key2 | * ------------ ------------ * * The lookup finds Key2 in znode zb. Lets say * there is no match and the name is greater so * we look left. When we find Key0, we end up * here. If we return now, we will insert into * znode za at slot n = 1. But that is invalid * according to the parent's keys. Key2 must * be inserted into znode zb. * * Note, this problem is not relevant for the * case when we go right, because * 'tnc_insert()' would correct the parent key.
*/ if (*n == (*zn)->child_cnt - 1) {
err = tnc_next(c, zn, n); if (err) { /* Should be impossible */
ubifs_assert(c, 0); if (err == -ENOENT)
err = -EINVAL; return err;
}
ubifs_assert(c, *n == 0);
*n = -1;
} return 0;
}
err = matches_name(c, &(*zn)->zbranch[*n], nm); if (err < 0) return err; if (err == NAME_LESS) return 0; if (err == NAME_MATCHES) return 1;
ubifs_assert(c, err == NAME_GREATER);
}
} else { int nn = *n; struct ubifs_znode *znode = *zn;
/* Look right */ while (1) {
err = tnc_next(c, &znode, &nn); if (err == -ENOENT) return 0; if (err < 0) return err; if (keys_cmp(c, &znode->zbranch[nn].key, key)) return 0;
err = matches_name(c, &znode->zbranch[nn], nm); if (err < 0) return err; if (err == NAME_GREATER) return 0;
*zn = znode;
*n = nn; if (err == NAME_MATCHES) return 1;
ubifs_assert(c, err == NAME_LESS);
}
}
}
/** * fallible_matches_name - determine if a dent matches a given name. * @c: UBIFS file-system description object * @zbr: zbranch of dent * @nm: name to match * * This is a "fallible" version of 'matches_name()' function which does not * panic if the direntry/xentry referred by @zbr does not exist on the media. * * This function checks if xentry/direntry referred by zbranch @zbr matches name * @nm. Returns %NAME_MATCHES it does, %NAME_LESS if the name referred by @zbr * is less than @nm, %NAME_GREATER if it is greater than @nm, and @NOT_ON_MEDIA * if xentry/direntry referred by @zbr does not exist on the media. A negative * error code is returned in case of failure.
*/ staticint fallible_matches_name(struct ubifs_info *c, struct ubifs_zbranch *zbr, conststruct fscrypt_name *nm)
{ struct ubifs_dent_node *dent; int nlen, err;
/* If possible, match against the dent in the leaf node cache */ if (!zbr->leaf) {
dent = kmalloc(zbr->len, GFP_NOFS); if (!dent) return -ENOMEM;
err = fallible_read_node(c, &zbr->key, zbr, dent); if (err < 0) goto out_free; if (err == 0) { /* The node was not present */
err = NOT_ON_MEDIA; goto out_free;
}
ubifs_assert(c, err == 1);
/** * fallible_resolve_collision - resolve a collision even if nodes are missing. * @c: UBIFS file-system description object * @key: key * @zn: znode is returned here * @n: branch number is passed and returned here * @nm: name of directory entry * @adding: indicates caller is adding a key to the TNC * * This is a "fallible" version of the 'resolve_collision()' function which * does not panic if one of the nodes referred to by TNC does not exist on the * media. This may happen when replaying the journal if a deleted node was * Garbage-collected and the commit was not done. A branch that refers to a node * that is not present is called a dangling branch. The following are the return * codes for this function: * o if @nm was found, %1 is returned and @zn and @n are set to the found * branch; * o if we are @adding and @nm was not found, %0 is returned; * o if we are not @adding and @nm was not found, but a dangling branch was * found, then %1 is returned and @zn and @n are set to the dangling branch; * o a negative error code is returned in case of failure.
*/ staticint fallible_resolve_collision(struct ubifs_info *c, constunion ubifs_key *key, struct ubifs_znode **zn, int *n, conststruct fscrypt_name *nm, int adding)
{ struct ubifs_znode *o_znode = NULL, *znode = *zn; int o_n, err, cmp, unsure = 0, nn = *n;
cmp = fallible_matches_name(c, &znode->zbranch[nn], nm); if (unlikely(cmp < 0)) return cmp; if (cmp == NAME_MATCHES) return 1; if (cmp == NOT_ON_MEDIA) {
o_znode = znode;
o_n = nn; /* * We are unlucky and hit a dangling branch straight away. * Now we do not really know where to go to find the needed * branch - to the left or to the right. Well, let's try left.
*/
unsure = 1;
} elseif (!adding)
unsure = 1; /* Remove a dangling branch wherever it is */
if (cmp == NAME_GREATER || unsure) { /* Look left */ while (1) {
err = tnc_prev(c, zn, n); if (err == -ENOENT) {
ubifs_assert(c, *n == 0);
*n = -1; break;
} if (err < 0) return err; if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) { /* See comments in 'resolve_collision()' */ if (*n == (*zn)->child_cnt - 1) {
err = tnc_next(c, zn, n); if (err) { /* Should be impossible */
ubifs_assert(c, 0); if (err == -ENOENT)
err = -EINVAL; return err;
}
ubifs_assert(c, *n == 0);
*n = -1;
} break;
}
err = fallible_matches_name(c, &(*zn)->zbranch[*n], nm); if (err < 0) return err; if (err == NAME_MATCHES) return 1; if (err == NOT_ON_MEDIA) {
o_znode = *zn;
o_n = *n; continue;
} if (!adding) continue; if (err == NAME_LESS) break; else
unsure = 0;
}
}
if (cmp == NAME_LESS || unsure) { /* Look right */
*zn = znode;
*n = nn; while (1) {
err = tnc_next(c, &znode, &nn); if (err == -ENOENT) break; if (err < 0) return err; if (keys_cmp(c, &znode->zbranch[nn].key, key)) break;
err = fallible_matches_name(c, &znode->zbranch[nn], nm); if (err < 0) return err; if (err == NAME_GREATER) break;
*zn = znode;
*n = nn; if (err == NAME_MATCHES) return 1; if (err == NOT_ON_MEDIA) {
o_znode = znode;
o_n = nn;
}
}
}
/* Never match a dangling branch when adding */ if (adding || !o_znode) return 0;
/** * matches_position - determine if a zbranch matches a given position. * @zbr: zbranch of dent * @lnum: LEB number of dent to match * @offs: offset of dent to match * * This function returns %1 if @lnum:@offs matches, and %0 otherwise.
*/ staticint matches_position(struct ubifs_zbranch *zbr, int lnum, int offs)
{ if (zbr->lnum == lnum && zbr->offs == offs) return 1; else return 0;
}
/** * resolve_collision_directly - resolve a collision directly. * @c: UBIFS file-system description object * @key: key of directory entry * @zn: znode is passed and returned here * @n: zbranch number is passed and returned here * @lnum: LEB number of dent node to match * @offs: offset of dent node to match * * This function is used for "hashed" keys to make sure the found directory or * extended attribute entry node is what was looked for. It is used when the * flash address of the right node is known (@lnum:@offs) which makes it much * easier to resolve collisions (no need to read entries and match full * names). This function returns %1 and sets @zn and @n if the collision is * resolved, %0 if @lnum:@offs is not found and @zn and @n are set to the * previous directory entry. Otherwise a negative error code is returned.
*/ staticint resolve_collision_directly(struct ubifs_info *c, constunion ubifs_key *key, struct ubifs_znode **zn, int *n, int lnum, int offs)
{ struct ubifs_znode *znode; int nn, err;
znode = *zn;
nn = *n; if (matches_position(&znode->zbranch[nn], lnum, offs)) return 1;
/* Look left */ while (1) {
err = tnc_prev(c, &znode, &nn); if (err == -ENOENT) break; if (err < 0) return err; if (keys_cmp(c, &znode->zbranch[nn].key, key)) break; if (matches_position(&znode->zbranch[nn], lnum, offs)) {
*zn = znode;
*n = nn; return 1;
}
}
/* Look right */
znode = *zn;
nn = *n; while (1) {
err = tnc_next(c, &znode, &nn); if (err == -ENOENT) return 0; if (err < 0) return err; if (keys_cmp(c, &znode->zbranch[nn].key, key)) return 0;
*zn = znode;
*n = nn; if (matches_position(&znode->zbranch[nn], lnum, offs)) return 1;
}
}
/** * dirty_cow_bottom_up - dirty a znode and its ancestors. * @c: UBIFS file-system description object * @znode: znode to dirty * * If we do not have a unique key that resides in a znode, then we cannot * dirty that znode from the top down (i.e. by using lookup_level0_dirty) * This function records the path back to the last dirty ancestor, and then * dirties the znodes on that path.
*/ staticstruct ubifs_znode *dirty_cow_bottom_up(struct ubifs_info *c, struct ubifs_znode *znode)
{ struct ubifs_znode *zp; int *path = c->bottom_up_buf, p = 0;
ubifs_assert(c, c->zroot.znode);
ubifs_assert(c, znode); if (c->zroot.znode->level > BOTTOM_UP_HEIGHT) {
kfree(c->bottom_up_buf);
c->bottom_up_buf = kmalloc_array(c->zroot.znode->level, sizeof(int),
GFP_NOFS); if (!c->bottom_up_buf) return ERR_PTR(-ENOMEM);
path = c->bottom_up_buf;
} if (c->zroot.znode->level) { /* Go up until parent is dirty */ while (1) { int n;
zp = znode->parent; if (!zp) break;
n = znode->iip;
ubifs_assert(c, p < c->zroot.znode->level);
path[p++] = n; if (!zp->cnext && ubifs_zn_dirty(znode)) break;
znode = zp;
}
}
/* Come back down, dirtying as we go */ while (1) { struct ubifs_zbranch *zbr;
/** * ubifs_lookup_level0 - search for zero-level znode. * @c: UBIFS file-system description object * @key: key to lookup * @zn: znode is returned here * @n: znode branch slot number is returned here * * This function looks up the TNC tree and search for zero-level znode which * refers key @key. The found zero-level znode is returned in @zn. There are 3 * cases: * o exact match, i.e. the found zero-level znode contains key @key, then %1 * is returned and slot number of the matched branch is stored in @n; * o not exact match, which means that zero-level znode does not contain * @key, then %0 is returned and slot number of the closest branch or %-1 * is stored in @n; In this case calling tnc_next() is mandatory. * o @key is so small that it is even less than the lowest key of the * leftmost zero-level node, then %0 is returned and %0 is stored in @n. * * Note, when the TNC tree is traversed, some znodes may be absent, then this * function reads corresponding indexing nodes and inserts them to TNC. In * case of failure, a negative error code is returned.
*/ int ubifs_lookup_level0(struct ubifs_info *c, constunion ubifs_key *key, struct ubifs_znode **zn, int *n)
{ int err, exact; struct ubifs_znode *znode;
time64_t time = ktime_get_seconds();
/* * Here is a tricky place. We have not found the key and this is a * "hashed" key, which may collide. The rest of the code deals with * situations like this: * * | 3 | 5 | * / \ * | 3 | 5 | | 6 | 7 | (x) * * Or more a complex example: * * | 1 | 5 | * / \ * | 1 | 3 | | 5 | 8 | * \ / * | 5 | 5 | | 6 | 7 | (x) * * In the examples, if we are looking for key "5", we may reach nodes * marked with "(x)". In this case what we have do is to look at the * left and see if there is "5" key there. If there is, we have to * return it. * * Note, this whole situation is possible because we allow to have * elements which are equivalent to the next key in the parent in the * children of current znode. For example, this happens if we split a * znode like this: | 3 | 5 | 5 | 6 | 7 |, which results in something * like this: * | 3 | 5 | * / \ * | 3 | 5 | | 5 | 6 | 7 | * ^ * And this becomes what is at the first "picture" after key "5" marked * with "^" is removed. What could be done is we could prohibit * splitting in the middle of the colliding sequence. Also, when * removing the leftmost key, we would have to correct the key of the * parent node, which would introduce additional complications. Namely, * if we changed the leftmost key of the parent znode, the garbage * collector would be unable to find it (GC is doing this when GC'ing * indexing LEBs). Although we already have an additional RB-tree where * we save such changed znodes (see 'ins_clr_old_idx_znode()') until * after the commit. But anyway, this does not look easy to implement * so we did not try this.
*/
err = tnc_prev(c, &znode, n); if (err == -ENOENT) {
dbg_tnc("found 0, lvl %d, n -1", znode->level);
*n = -1; return 0;
} if (unlikely(err < 0)) return err; if (keys_cmp(c, key, &znode->zbranch[*n].key)) {
dbg_tnc("found 0, lvl %d, n -1", znode->level);
*n = -1; return 0;
}
/** * lookup_level0_dirty - search for zero-level znode dirtying. * @c: UBIFS file-system description object * @key: key to lookup * @zn: znode is returned here * @n: znode branch slot number is returned here * * This function looks up the TNC tree and search for zero-level znode which * refers key @key. The found zero-level znode is returned in @zn. There are 3 * cases: * o exact match, i.e. the found zero-level znode contains key @key, then %1 * is returned and slot number of the matched branch is stored in @n; * o not exact match, which means that zero-level znode does not contain @key * then %0 is returned and slot number of the closed branch is stored in * @n; * o @key is so small that it is even less than the lowest key of the * leftmost zero-level node, then %0 is returned and %-1 is stored in @n. * * Additionally all znodes in the path from the root to the located zero-level * znode are marked as dirty. * * Note, when the TNC tree is traversed, some znodes may be absent, then this * function reads corresponding indexing nodes and inserts them to TNC. In * case of failure, a negative error code is returned.
*/ staticint lookup_level0_dirty(struct ubifs_info *c, constunion ubifs_key *key, struct ubifs_znode **zn, int *n)
{ int err, exact; struct ubifs_znode *znode;
time64_t time = ktime_get_seconds();
dbg_tnck(key, "search and dirty key ");
znode = c->zroot.znode; if (unlikely(!znode)) {
znode = ubifs_load_znode(c, &c->zroot, NULL, 0); if (IS_ERR(znode)) return PTR_ERR(znode);
}
znode = dirty_cow_znode(c, &c->zroot); if (IS_ERR(znode)) return PTR_ERR(znode);
znode->time = time;
while (1) { struct ubifs_zbranch *zbr;
exact = ubifs_search_zbranch(c, znode, key, n);
if (znode->level == 0) break;
if (*n < 0)
*n = 0;
zbr = &znode->zbranch[*n];
if (zbr->znode) {
znode->time = time;
znode = dirty_cow_znode(c, zbr); if (IS_ERR(znode)) return PTR_ERR(znode); continue;
}
/* znode is not in TNC cache, load it from the media */
znode = ubifs_load_znode(c, zbr, znode, *n); if (IS_ERR(znode)) return PTR_ERR(znode);
znode = dirty_cow_znode(c, zbr); if (IS_ERR(znode)) return PTR_ERR(znode);
}
/** * maybe_leb_gced - determine if a LEB may have been garbage collected. * @c: UBIFS file-system description object * @lnum: LEB number * @gc_seq1: garbage collection sequence number * * This function determines if @lnum may have been garbage collected since * sequence number @gc_seq1. If it may have been then %1 is returned, otherwise * %0 is returned.
*/ staticint maybe_leb_gced(struct ubifs_info *c, int lnum, int gc_seq1)
{ int gc_seq2, gced_lnum;
gced_lnum = c->gced_lnum;
smp_rmb();
gc_seq2 = c->gc_seq; /* Same seq means no GC */ if (gc_seq1 == gc_seq2) return 0; /* Different by more than 1 means we don't know */ if (gc_seq1 + 1 != gc_seq2) return 1; /* * We have seen the sequence number has increased by 1. Now we need to * be sure we read the right LEB number, so read it again.
*/
smp_rmb(); if (gced_lnum != c->gced_lnum) return 1; /* Finally we can check lnum */ if (gced_lnum == lnum) return 1; return 0;
}
/** * ubifs_tnc_locate - look up a file-system node and return it and its location. * @c: UBIFS file-system description object * @key: node key to lookup * @node: the node is returned here * @lnum: LEB number is returned here * @offs: offset is returned here * * This function looks up and reads node with key @key. The caller has to make * sure the @node buffer is large enough to fit the node. Returns zero in case * of success, %-ENOENT if the node was not found, and a negative error code in * case of failure. The node location can be returned in @lnum and @offs.
*/ int ubifs_tnc_locate(struct ubifs_info *c, constunion ubifs_key *key, void *node, int *lnum, int *offs)
{ int found, n, err, safely = 0, gc_seq1; struct ubifs_znode *znode; struct ubifs_zbranch zbr, *zt;
again:
mutex_lock(&c->tnc_mutex);
found = ubifs_lookup_level0(c, key, &znode, &n); if (!found) {
err = -ENOENT; goto out;
} elseif (found < 0) {
err = found; goto out;
}
zt = &znode->zbranch[n]; if (lnum) {
*lnum = zt->lnum;
*offs = zt->offs;
} if (is_hash_key(c, key)) { /* * In this case the leaf node cache gets used, so we pass the * address of the zbranch and keep the mutex locked
*/
err = tnc_read_hashed_node(c, zt, node); goto out;
} if (safely) {
err = ubifs_tnc_read_node(c, zt, node); goto out;
} /* Drop the TNC mutex prematurely and race with garbage collection */
zbr = znode->zbranch[n];
gc_seq1 = c->gc_seq;
mutex_unlock(&c->tnc_mutex);
if (ubifs_get_wbuf(c, zbr.lnum)) { /* We do not GC journal heads */
err = ubifs_tnc_read_node(c, &zbr, node); return err;
}
err = fallible_read_node(c, key, &zbr, node); if (err <= 0 || maybe_leb_gced(c, zbr.lnum, gc_seq1)) { /* * The node may have been GC'ed out from under us so try again * while keeping the TNC mutex locked.
*/
safely = 1; goto again;
} return 0;
out:
mutex_unlock(&c->tnc_mutex); return err;
}
/** * ubifs_tnc_get_bu_keys - lookup keys for bulk-read. * @c: UBIFS file-system description object * @bu: bulk-read parameters and results * * Lookup consecutive data node keys for the same inode that reside * consecutively in the same LEB. This function returns zero in case of success * and a negative error code in case of failure. * * Note, if the bulk-read buffer length (@bu->buf_len) is known, this function * makes sure bulk-read nodes fit the buffer. Otherwise, this function prepares * maximum possible amount of nodes for bulk-read.
*/ int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu)
{ int n, err = 0, lnum = -1, offs; int len; unsignedint block = key_block(c, &bu->key); struct ubifs_znode *znode;
bu->cnt = 0;
bu->blk_cnt = 0;
bu->eof = 0;
mutex_lock(&c->tnc_mutex); /* Find first key */
err = ubifs_lookup_level0(c, &bu->key, &znode, &n); if (err < 0) goto out; if (err) { /* Key found */
len = znode->zbranch[n].len; /* The buffer must be big enough for at least 1 node */ if (len > bu->buf_len) {
err = -EINVAL; goto out;
} /* Add this key */
bu->zbranch[bu->cnt++] = znode->zbranch[n];
bu->blk_cnt += 1;
lnum = znode->zbranch[n].lnum;
offs = ALIGN(znode->zbranch[n].offs + len, 8);
} while (1) { struct ubifs_zbranch *zbr; union ubifs_key *key; unsignedint next_block;
/* Find next key */
err = tnc_next(c, &znode, &n); if (err) goto out;
zbr = &znode->zbranch[n];
key = &zbr->key; /* See if there is another data key for this file */ if (key_inum(c, key) != key_inum(c, &bu->key) ||
key_type(c, key) != UBIFS_DATA_KEY) {
err = -ENOENT; goto out;
} if (lnum < 0) { /* First key found */
lnum = zbr->lnum;
offs = ALIGN(zbr->offs + zbr->len, 8);
len = zbr->len; if (len > bu->buf_len) {
err = -EINVAL; goto out;
}
} else { /* * The data nodes must be in consecutive positions in * the same LEB.
*/ if (zbr->lnum != lnum || zbr->offs != offs) goto out;
offs += ALIGN(zbr->len, 8);
len = ALIGN(len, 8) + zbr->len; /* Must not exceed buffer length */ if (len > bu->buf_len) goto out;
} /* Allow for holes */
next_block = key_block(c, key);
bu->blk_cnt += (next_block - block - 1); if (bu->blk_cnt >= UBIFS_MAX_BULK_READ) goto out;
block = next_block; /* Add this key */
bu->zbranch[bu->cnt++] = *zbr;
bu->blk_cnt += 1; /* See if we have room for more */ if (bu->cnt >= UBIFS_MAX_BULK_READ) goto out; if (bu->blk_cnt >= UBIFS_MAX_BULK_READ) goto out;
}
out: if (err == -ENOENT) {
bu->eof = 1;
err = 0;
}
bu->gc_seq = c->gc_seq;
mutex_unlock(&c->tnc_mutex); if (err) return err; /* * An enormous hole could cause bulk-read to encompass too many * page cache pages, so limit the number here.
*/ if (bu->blk_cnt > UBIFS_MAX_BULK_READ)
bu->blk_cnt = UBIFS_MAX_BULK_READ; /* * Ensure that bulk-read covers a whole number of page cache * pages.
*/ if (UBIFS_BLOCKS_PER_PAGE == 1 ||
!(bu->blk_cnt & (UBIFS_BLOCKS_PER_PAGE - 1))) return 0; if (bu->eof) { /* At the end of file we can round up */
bu->blk_cnt += UBIFS_BLOCKS_PER_PAGE - 1; return 0;
} /* Exclude data nodes that do not make up a whole page cache page */
block = key_block(c, &bu->key) + bu->blk_cnt;
block &= ~(UBIFS_BLOCKS_PER_PAGE - 1); while (bu->cnt) { if (key_block(c, &bu->zbranch[bu->cnt - 1].key) < block) break;
bu->cnt -= 1;
} return 0;
}
/** * read_wbuf - bulk-read from a LEB with a wbuf. * @wbuf: wbuf that may overlap the read * @buf: buffer into which to read * @len: read length * @lnum: LEB number from which to read * @offs: offset from which to read * * This functions returns %0 on success or a negative error code on failure.
*/ staticint read_wbuf(struct ubifs_wbuf *wbuf, void *buf, int len, int lnum, int offs)
{ conststruct ubifs_info *c = wbuf->c; int rlen, overlap;
spin_lock(&wbuf->lock);
overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs); if (!overlap) { /* We may safely unlock the write-buffer and read the data */
spin_unlock(&wbuf->lock); return ubifs_leb_read(c, lnum, buf, offs, len, 0);
}
/* Don't read under wbuf */
rlen = wbuf->offs - offs; if (rlen < 0)
rlen = 0;
/* Copy the rest from the write-buffer */
memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
spin_unlock(&wbuf->lock);
if (rlen > 0) /* Read everything that goes before write-buffer */ return ubifs_leb_read(c, lnum, buf, offs, rlen, 0);
return 0;
}
/** * validate_data_node - validate data nodes for bulk-read. * @c: UBIFS file-system description object * @buf: buffer containing data node to validate * @zbr: zbranch of data node to validate * * This functions returns %0 on success or a negative error code on failure.
*/ staticint validate_data_node(struct ubifs_info *c, void *buf, struct ubifs_zbranch *zbr)
{ union ubifs_key key1; struct ubifs_ch *ch = buf; int err, len;
if (ch->node_type != UBIFS_DATA_NODE) {
ubifs_err(c, "bad node type (%d but expected %d)",
ch->node_type, UBIFS_DATA_NODE); goto out_err;
}
len = le32_to_cpu(ch->len); if (len != zbr->len) {
ubifs_err(c, "bad node length %d, expected %d", len, zbr->len); goto out_err;
}
/* Make sure the key of the read node is correct */
key_read(c, buf + UBIFS_KEY_OFFSET, &key1); if (!keys_eq(c, &zbr->key, &key1)) {
ubifs_err(c, "bad key in node at LEB %d:%d",
zbr->lnum, zbr->offs);
dbg_tnck(&zbr->key, "looked for key ");
dbg_tnck(&key1, "found node's key "); goto out_err;
}
/** * ubifs_tnc_bulk_read - read a number of data nodes in one go. * @c: UBIFS file-system description object * @bu: bulk-read parameters and results * * This functions reads and validates the data nodes that were identified by the * 'ubifs_tnc_get_bu_keys()' function. This functions returns %0 on success, * -EAGAIN to indicate a race with GC, or another negative error code on * failure.
*/ int ubifs_tnc_bulk_read(struct ubifs_info *c, struct bu_info *bu)
{ int lnum = bu->zbranch[0].lnum, offs = bu->zbranch[0].offs, len, err, i; struct ubifs_wbuf *wbuf; void *buf;
len = bu->zbranch[bu->cnt - 1].offs;
len += bu->zbranch[bu->cnt - 1].len - offs; if (len > bu->buf_len) {
ubifs_err(c, "buffer too small %d vs %d", bu->buf_len, len); return -EINVAL;
}
/* Do the read */
wbuf = ubifs_get_wbuf(c, lnum); if (wbuf)
err = read_wbuf(wbuf, bu->buf, len, lnum, offs); else
err = ubifs_leb_read(c, lnum, bu->buf, offs, len, 0);
/* Check for a race with GC */ if (maybe_leb_gced(c, lnum, bu->gc_seq)) return -EAGAIN;
if (err && err != -EBADMSG) {
ubifs_err(c, "failed to read from LEB %d:%d, error %d",
lnum, offs, err);
dump_stack();
dbg_tnck(&bu->key, "key "); return err;
}
/* Validate the nodes read */
buf = bu->buf; for (i = 0; i < bu->cnt; i++) {
err = validate_data_node(c, buf, &bu->zbranch[i]); if (err) return err;
buf = buf + ALIGN(bu->zbranch[i].len, 8);
}
return 0;
}
/** * do_lookup_nm- look up a "hashed" node. * @c: UBIFS file-system description object * @key: node key to lookup * @node: the node is returned here * @nm: node name * * This function looks up and reads a node which contains name hash in the key. * Since the hash may have collisions, there may be many nodes with the same * key, so we have to sequentially look to all of them until the needed one is * found. This function returns zero in case of success, %-ENOENT if the node * was not found, and a negative error code in case of failure.
*/ staticint do_lookup_nm(struct ubifs_info *c, constunion ubifs_key *key, void *node, conststruct fscrypt_name *nm)
{ int found, n, err; struct ubifs_znode *znode;
/** * ubifs_tnc_lookup_nm - look up a "hashed" node. * @c: UBIFS file-system description object * @key: node key to lookup * @node: the node is returned here * @nm: node name * * This function looks up and reads a node which contains name hash in the key. * Since the hash may have collisions, there may be many nodes with the same * key, so we have to sequentially look to all of them until the needed one is * found. This function returns zero in case of success, %-ENOENT if the node * was not found, and a negative error code in case of failure.
*/ int ubifs_tnc_lookup_nm(struct ubifs_info *c, constunion ubifs_key *key, void *node, conststruct fscrypt_name *nm)
{ int err, len; conststruct ubifs_dent_node *dent = node;
/* * We assume that in most of the cases there are no name collisions and * 'ubifs_tnc_lookup()' returns us the right direntry.
*/
err = ubifs_tnc_lookup(c, key, node); if (err) return err;
len = le16_to_cpu(dent->nlen); if (fname_len(nm) == len && !memcmp(dent->name, fname_name(nm), len)) return 0;
/* * Unluckily, there are hash collisions and we have to iterate over * them look at each direntry with colliding name hash sequentially.
*/
return do_lookup_nm(c, key, node, nm);
}
staticint search_dh_cookie(struct ubifs_info *c, constunion ubifs_key *key, struct ubifs_dent_node *dent, uint32_t cookie, struct ubifs_znode **zn, int *n, int exact)
{ int err; struct ubifs_znode *znode = *zn; struct ubifs_zbranch *zbr; union ubifs_key *dkey;
if (!exact) {
err = tnc_next(c, &znode, n); if (err) return err;
}
for (;;) {
zbr = &znode->zbranch[*n];
dkey = &zbr->key;
/** * ubifs_tnc_lookup_dh - look up a "double hashed" node. * @c: UBIFS file-system description object * @key: node key to lookup * @node: the node is returned here * @cookie: node cookie for collision resolution * * This function looks up and reads a node which contains name hash in the key. * Since the hash may have collisions, there may be many nodes with the same * key, so we have to sequentially look to all of them until the needed one * with the same cookie value is found. * This function returns zero in case of success, %-ENOENT if the node * was not found, and a negative error code in case of failure.
*/ int ubifs_tnc_lookup_dh(struct ubifs_info *c, constunion ubifs_key *key, void *node, uint32_t cookie)
{ int err; conststruct ubifs_dent_node *dent = node;
if (!c->double_hash) return -EOPNOTSUPP;
/* * We assume that in most of the cases there are no name collisions and * 'ubifs_tnc_lookup()' returns us the right direntry.
*/
err = ubifs_tnc_lookup(c, key, node); if (err) return err;
if (le32_to_cpu(dent->cookie) == cookie) return 0;
/* * Unluckily, there are hash collisions and we have to iterate over * them look at each direntry with colliding name hash sequentially.
*/ return do_lookup_dh(c, key, node, cookie);
}
/** * correct_parent_keys - correct parent znodes' keys. * @c: UBIFS file-system description object * @znode: znode to correct parent znodes for * * This is a helper function for 'tnc_insert()'. When the key of the leftmost * zbranch changes, keys of parent znodes have to be corrected. This helper * function is called in such situations and corrects the keys if needed.
*/ staticvoid correct_parent_keys(conststruct ubifs_info *c, struct ubifs_znode *znode)
{ union ubifs_key *key, *key1;
/** * insert_zbranch - insert a zbranch into a znode. * @c: UBIFS file-system description object * @znode: znode into which to insert * @zbr: zbranch to insert * @n: slot number to insert to * * This is a helper function for 'tnc_insert()'. UBIFS does not allow "gaps" in * znode's array of zbranches and keeps zbranches consolidated, so when a new * zbranch has to be inserted to the @znode->zbranches[]' array at the @n-th * slot, zbranches starting from @n have to be moved right.
*/ staticvoid insert_zbranch(struct ubifs_info *c, struct ubifs_znode *znode, conststruct ubifs_zbranch *zbr, int n)
{ int i;
ubifs_assert(c, ubifs_zn_dirty(znode));
if (znode->level) { for (i = znode->child_cnt; i > n; i--) {
znode->zbranch[i] = znode->zbranch[i - 1]; if (znode->zbranch[i].znode)
znode->zbranch[i].znode->iip = i;
} if (zbr->znode)
zbr->znode->iip = n;
} else for (i = znode->child_cnt; i > n; i--)
znode->zbranch[i] = znode->zbranch[i - 1];
znode->zbranch[n] = *zbr;
znode->child_cnt += 1;
/* * After inserting at slot zero, the lower bound of the key range of * this znode may have changed. If this znode is subsequently split * then the upper bound of the key range may change, and furthermore * it could change to be lower than the original lower bound. If that * happens, then it will no longer be possible to find this znode in the * TNC using the key from the index node on flash. That is bad because * if it is not found, we will assume it is obsolete and may overwrite * it. Then if there is an unclean unmount, we will start using the * old index which will be broken. * * So we first mark znodes that have insertions at slot zero, and then * if they are split we add their lnum/offs to the old_idx tree.
*/ if (n == 0)
znode->alt = 1;
}
/** * tnc_insert - insert a node into TNC. * @c: UBIFS file-system description object * @znode: znode to insert into * @zbr: branch to insert * @n: slot number to insert new zbranch to * * This function inserts a new node described by @zbr into znode @znode. If * znode does not have a free slot for new zbranch, it is split. Parent znodes * are splat as well if needed. Returns zero in case of success or a negative * error code in case of failure.
*/ staticint tnc_insert(struct ubifs_info *c, struct ubifs_znode *znode, struct ubifs_zbranch *zbr, int n)
{ struct ubifs_znode *zn, *zi, *zp; int i, keep, move, appending = 0; union ubifs_key *key = &zbr->key, *key1;
ubifs_assert(c, n >= 0 && n <= c->fanout);
/* Implement naive insert for now */
again:
zp = znode->parent; if (znode->child_cnt < c->fanout) {
ubifs_assert(c, n != c->fanout);
dbg_tnck(key, "inserted at %d level %d, key ", n, znode->level);
insert_zbranch(c, znode, zbr, n);
/* Ensure parent's key is correct */ if (n == 0 && zp && znode->iip == 0)
correct_parent_keys(c, znode);
return 0;
}
/* * Unfortunately, @znode does not have more empty slots and we have to * split it.
*/
dbg_tnck(key, "splitting level %d, key ", znode->level);
if (znode->alt) /* * We can no longer be sure of finding this znode by key, so we * record it in the old_idx tree.
*/
ins_clr_old_idx_znode(c, znode);
/** * ubifs_tnc_add - add a node to TNC. * @c: UBIFS file-system description object * @key: key to add * @lnum: LEB number of node * @offs: node offset * @len: node length * @hash: The hash over the node * * This function adds a node with key @key to TNC. The node may be new or it may * obsolete some existing one. Returns %0 on success or negative error code on * failure.
*/ int ubifs_tnc_add(struct ubifs_info *c, constunion ubifs_key *key, int lnum, int offs, int len, const u8 *hash)
{ int found, n, err = 0; struct ubifs_znode *znode;
mutex_lock(&c->tnc_mutex);
dbg_tnck(key, "%d:%d, len %d, key ", lnum, offs, len);
found = lookup_level0_dirty(c, key, &znode, &n); if (!found) { struct ubifs_zbranch zbr;
/** * ubifs_tnc_replace - replace a node in the TNC only if the old node is found. * @c: UBIFS file-system description object * @key: key to add * @old_lnum: LEB number of old node * @old_offs: old node offset * @lnum: LEB number of node * @offs: node offset * @len: node length * * This function replaces a node with key @key in the TNC only if the old node * is found. This function is called by garbage collection when node are moved. * Returns %0 on success or negative error code on failure.
*/ int ubifs_tnc_replace(struct ubifs_info *c, constunion ubifs_key *key, int old_lnum, int old_offs, int lnum, int offs, int len)
{ int found, n, err = 0; struct ubifs_znode *znode;
mutex_lock(&c->tnc_mutex);
dbg_tnck(key, "old LEB %d:%d, new LEB %d:%d, len %d, key ", old_lnum,
old_offs, lnum, offs, len);
found = lookup_level0_dirty(c, key, &znode, &n); if (found < 0) {
err = found; goto out_unlock;
}
if (found == 1) { struct ubifs_zbranch *zbr = &znode->zbranch[n];
found = 0; if (zbr->lnum == old_lnum && zbr->offs == old_offs) {
lnc_free(zbr);
err = ubifs_add_dirt(c, zbr->lnum, zbr->len); if (err) goto out_unlock;
zbr->lnum = lnum;
zbr->offs = offs;
zbr->len = len;
found = 1;
} elseif (is_hash_key(c, key)) {
found = resolve_collision_directly(c, key, &znode, &n,
old_lnum, old_offs);
dbg_tnc("rc returned %d, znode %p, n %d, LEB %d:%d",
found, znode, n, old_lnum, old_offs); if (found < 0) {
err = found; goto out_unlock;
}
if (found) { /* Ensure the znode is dirtied */ if (znode->cnext || !ubifs_zn_dirty(znode)) {
znode = dirty_cow_bottom_up(c, znode); if (IS_ERR(znode)) {
err = PTR_ERR(znode); goto out_unlock;
}
}
zbr = &znode->zbranch[n];
lnc_free(zbr);
err = ubifs_add_dirt(c, zbr->lnum,
zbr->len); if (err) goto out_unlock;
zbr->lnum = lnum;
zbr->offs = offs;
zbr->len = len;
}
}
}
/** * ubifs_tnc_add_nm - add a "hashed" node to TNC. * @c: UBIFS file-system description object * @key: key to add * @lnum: LEB number of node * @offs: node offset * @len: node length * @hash: The hash over the node * @nm: node name * * This is the same as 'ubifs_tnc_add()' but it should be used with keys which * may have collisions, like directory entry keys.
*/ int ubifs_tnc_add_nm(struct ubifs_info *c, constunion ubifs_key *key, int lnum, int offs, int len, const u8 *hash, conststruct fscrypt_name *nm)
{ int found, n, err = 0; struct ubifs_znode *znode;
zbr.znode = NULL;
zbr.lnum = lnum;
zbr.offs = offs;
zbr.len = len;
ubifs_copy_hash(c, hash, zbr.hash);
key_copy(c, key, &zbr.key);
err = tnc_insert(c, znode, &zbr, n + 1); if (err) goto out_unlock; if (c->replaying) { /* * We did not find it in the index so there may be a * dangling branch still in the index. So we remove it * by passing 'ubifs_tnc_remove_nm()' the same key but * an unmatchable name.
*/ struct fscrypt_name noname = { .disk_name = { .name = "", .len = 1 } };
/** * tnc_delete - delete a znode form TNC. * @c: UBIFS file-system description object * @znode: znode to delete from * @n: zbranch slot number to delete * * This function deletes a leaf node from @n-th slot of @znode. Returns zero in * case of success and a negative error code in case of failure.
*/ staticint tnc_delete(struct ubifs_info *c, struct ubifs_znode *znode, int n)
{ struct ubifs_zbranch *zbr; struct ubifs_znode *zp; int i, err;
/* Delete without merge for now */
ubifs_assert(c, znode->level == 0);
ubifs_assert(c, n >= 0 && n < c->fanout);
dbg_tnck(&znode->zbranch[n].key, "deleting key ");
/** * ubifs_tnc_remove - remove an index entry of a node. * @c: UBIFS file-system description object * @key: key of node * * Returns %0 on success or negative error code on failure.
*/ int ubifs_tnc_remove(struct ubifs_info *c, constunion ubifs_key *key)
{ int found, n, err = 0; struct ubifs_znode *znode;
mutex_lock(&c->tnc_mutex);
dbg_tnck(key, "key ");
found = lookup_level0_dirty(c, key, &znode, &n); if (found < 0) {
err = found; goto out_unlock;
} if (found == 1)
err = tnc_delete(c, znode, n); if (!err)
err = dbg_check_tnc(c, 0);
/** * ubifs_tnc_remove_nm - remove an index entry for a "hashed" node. * @c: UBIFS file-system description object * @key: key of node * @nm: directory entry name * * Returns %0 on success or negative error code on failure.
*/ int ubifs_tnc_remove_nm(struct ubifs_info *c, constunion ubifs_key *key, conststruct fscrypt_name *nm)
{ int n, err; struct ubifs_znode *znode;
/** * key_in_range - determine if a key falls within a range of keys. * @c: UBIFS file-system description object * @key: key to check * @from_key: lowest key in range * @to_key: highest key in range * * This function returns %1 if the key is in range and %0 otherwise.
*/ staticint key_in_range(struct ubifs_info *c, union ubifs_key *key, union ubifs_key *from_key, union ubifs_key *to_key)
{ if (keys_cmp(c, key, from_key) < 0) return 0; if (keys_cmp(c, key, to_key) > 0) return 0; return 1;
}
/** * ubifs_tnc_remove_range - remove index entries in range. * @c: UBIFS file-system description object * @from_key: lowest key to remove * @to_key: highest key to remove * * This function removes index entries starting at @from_key and ending at * @to_key. This function returns zero in case of success and a negative error * code in case of failure.
*/ int ubifs_tnc_remove_range(struct ubifs_info *c, union ubifs_key *from_key, union ubifs_key *to_key)
{ int i, n, k, err = 0; struct ubifs_znode *znode; union ubifs_key *key;
mutex_lock(&c->tnc_mutex); while (1) { /* Find first level 0 znode that contains keys to remove */
err = ubifs_lookup_level0(c, from_key, &znode, &n); if (err < 0) goto out_unlock;
/* Ensure the znode is dirtied */ if (znode->cnext || !ubifs_zn_dirty(znode)) {
znode = dirty_cow_bottom_up(c, znode); if (IS_ERR(znode)) {
err = PTR_ERR(znode); goto out_unlock;
}
}
/* Remove all keys in range except the first */ for (i = n + 1, k = 0; i < znode->child_cnt; i++, k++) {
key = &znode->zbranch[i].key; if (!key_in_range(c, key, from_key, to_key)) break;
lnc_free(&znode->zbranch[i]);
err = ubifs_add_dirt(c, znode->zbranch[i].lnum,
znode->zbranch[i].len); if (err) {
ubifs_dump_znode(c, znode); goto out_unlock;
}
dbg_tnck(key, "removing key ");
} if (k) { for (i = n + 1 + k; i < znode->child_cnt; i++)
znode->zbranch[i - k] = znode->zbranch[i];
znode->child_cnt -= k;
}
/* Now delete the first */
err = tnc_delete(c, znode, n); if (err) goto out_unlock;
}
/** * ubifs_tnc_remove_ino - remove an inode from TNC. * @c: UBIFS file-system description object * @inum: inode number to remove * * This function remove inode @inum and all the extended attributes associated * with the anode from TNC and returns zero in case of success or a negative * error code in case of failure.
*/ int ubifs_tnc_remove_ino(struct ubifs_info *c, ino_t inum)
{ union ubifs_key key1, key2; struct ubifs_dent_node *xent, *pxent = NULL; struct fscrypt_name nm = {0};
dbg_tnc("ino %lu", (unsignedlong)inum);
/* * Walk all extended attribute entries and remove them together with * corresponding extended attribute inodes.
*/
lowest_xent_key(c, &key1, inum); while (1) {
ino_t xattr_inum; int err;
xent = ubifs_tnc_next_ent(c, &key1, &nm); if (IS_ERR(xent)) {
err = PTR_ERR(xent); if (err == -ENOENT) break;
kfree(pxent); return err;
}
/** * ubifs_tnc_next_ent - walk directory or extended attribute entries. * @c: UBIFS file-system description object * @key: key of last entry * @nm: name of last entry found or %NULL * * This function finds and reads the next directory or extended attribute entry * after the given key (@key) if there is one. @nm is used to resolve * collisions. * * If the name of the current entry is not known and only the key is known, * @nm->name has to be %NULL. In this case the semantics of this function is a * little bit different and it returns the entry corresponding to this key, not * the next one. If the key was not found, the closest "right" entry is * returned. * * If the fist entry has to be found, @key has to contain the lowest possible * key value for this inode and @name has to be %NULL. * * This function returns the found directory or extended attribute entry node * in case of success, %-ENOENT is returned if no entry was found, and a * negative error code is returned in case of failure.
*/ struct ubifs_dent_node *ubifs_tnc_next_ent(struct ubifs_info *c, union ubifs_key *key, conststruct fscrypt_name *nm)
{ int n, err, type = key_type(c, key); struct ubifs_znode *znode; struct ubifs_dent_node *dent; struct ubifs_zbranch *zbr; union ubifs_key *dkey;
if (fname_len(nm) > 0) { if (err) { /* Handle collisions */ if (c->replaying)
err = fallible_resolve_collision(c, key, &znode, &n,
nm, 0); else
err = resolve_collision(c, key, &znode, &n, nm);
dbg_tnc("rc returned %d, znode %p, n %d",
err, znode, n); if (unlikely(err < 0)) goto out_unlock;
}
/* Now find next entry */
err = tnc_next(c, &znode, &n); if (unlikely(err)) goto out_unlock;
} else { /* * The full name of the entry was not given, in which case the * behavior of this function is a little different and it * returns current entry, not the next one.
*/ if (!err) { /* * However, the given key does not exist in the TNC * tree and @znode/@n variables contain the closest * "preceding" element. Switch to the next one.
*/
err = tnc_next(c, &znode, &n); if (err) goto out_unlock;
}
}
/* * The above 'tnc_next()' call could lead us to the next inode, check * this.
*/
dkey = &zbr->key; if (key_inum(c, dkey) != key_inum(c, key) ||
key_type(c, dkey) != type) {
err = -ENOENT; goto out_free;
}
err = tnc_read_hashed_node(c, zbr, dent); if (unlikely(err)) goto out_free;
/** * tnc_destroy_cnext - destroy left-over obsolete znodes from a failed commit. * @c: UBIFS file-system description object * * Destroy left-over obsolete znodes from a failed commit.
*/ staticvoid tnc_destroy_cnext(struct ubifs_info *c)
{ struct ubifs_znode *cnext;
if (!c->cnext) return;
ubifs_assert(c, c->cmt_state == COMMIT_BROKEN);
cnext = c->cnext; do { struct ubifs_znode *znode = cnext;
cnext = cnext->cnext; if (ubifs_zn_obsolete(znode))
kfree(znode); elseif (!ubifs_zn_cow(znode)) { /* * Don't forget to update clean znode count after * committing failed, because ubifs will check this * count while closing tnc. Non-obsolete znode could * be re-dirtied during committing process, so dirty * flag is untrustable. The flag 'COW_ZNODE' is set * for each dirty znode before committing, and it is * cleared as long as the znode become clean, so we * can statistic clean znode count according to this * flag.
*/
atomic_long_inc(&c->clean_zn_cnt);
atomic_long_inc(&ubifs_clean_zn_cnt);
}
} while (cnext && cnext != c->cnext);
}
/** * ubifs_tnc_close - close TNC subsystem and free all related resources. * @c: UBIFS file-system description object
*/ void ubifs_tnc_close(struct ubifs_info *c)
{
tnc_destroy_cnext(c);
ubifs_destroy_tnc_tree(c);
kfree(c->gap_lebs);
kfree(c->ilebs);
destroy_old_idx(c);
}
/** * left_znode - get the znode to the left. * @c: UBIFS file-system description object * @znode: znode * * This function returns a pointer to the znode to the left of @znode or NULL if * there is not one. A negative error code is returned on failure.
*/ staticstruct ubifs_znode *left_znode(struct ubifs_info *c, struct ubifs_znode *znode)
{ int level = znode->level;
while (1) { int n = znode->iip - 1;
/* Go up until we can go left */
znode = znode->parent; if (!znode) return NULL; if (n >= 0) { /* Now go down the rightmost branch to 'level' */
znode = get_znode(c, znode, n); if (IS_ERR(znode)) return znode; while (znode->level != level) {
n = znode->child_cnt - 1;
znode = get_znode(c, znode, n); if (IS_ERR(znode)) return znode;
} break;
}
} return znode;
}
/** * right_znode - get the znode to the right. * @c: UBIFS file-system description object * @znode: znode * * This function returns a pointer to the znode to the right of @znode or NULL * if there is not one. A negative error code is returned on failure.
*/ staticstruct ubifs_znode *right_znode(struct ubifs_info *c, struct ubifs_znode *znode)
{ int level = znode->level;
while (1) { int n = znode->iip + 1;
/* Go up until we can go right */
znode = znode->parent; if (!znode) return NULL; if (n < znode->child_cnt) { /* Now go down the leftmost branch to 'level' */
znode = get_znode(c, znode, n); if (IS_ERR(znode)) return znode; while (znode->level != level) {
znode = get_znode(c, znode, 0); if (IS_ERR(znode)) return znode;
} break;
}
} return znode;
}
/** * lookup_znode - find a particular indexing node from TNC. * @c: UBIFS file-system description object * @key: index node key to lookup * @level: index node level * @lnum: index node LEB number * @offs: index node offset * * This function searches an indexing node by its first key @key and its * address @lnum:@offs. It looks up the indexing tree by pulling all indexing * nodes it traverses to TNC. This function is called for indexing nodes which * were found on the media by scanning, for example when garbage-collecting or * when doing in-the-gaps commit. This means that the indexing node which is * looked for does not have to have exactly the same leftmost key @key, because * the leftmost key may have been changed, in which case TNC will contain a * dirty znode which still refers the same @lnum:@offs. This function is clever * enough to recognize such indexing nodes. * * Note, if a znode was deleted or changed too much, then this function will * not find it. For situations like this UBIFS has the old index RB-tree * (indexed by @lnum:@offs). * * This function returns a pointer to the znode found or %NULL if it is not * found. A negative error code is returned on failure.
*/ staticstruct ubifs_znode *lookup_znode(struct ubifs_info *c, union ubifs_key *key, int level, int lnum, int offs)
{ struct ubifs_znode *znode, *zn; int n, nn;
/* * The arguments have probably been read off flash, so don't assume * they are valid.
*/ if (level < 0) return ERR_PTR(-EINVAL);
/* Get the root znode */
znode = c->zroot.znode; if (!znode) {
znode = ubifs_load_znode(c, &c->zroot, NULL, 0); if (IS_ERR(znode)) return znode;
} /* Check if it is the one we are looking for */ if (c->zroot.lnum == lnum && c->zroot.offs == offs) return znode; /* Descend to the parent level i.e. (level + 1) */ if (level >= znode->level) return NULL; while (1) {
ubifs_search_zbranch(c, znode, key, &n); if (n < 0) { /* * We reached a znode where the leftmost key is greater * than the key we are searching for. This is the same * situation as the one described in a huge comment at * the end of the 'ubifs_lookup_level0()' function. And * for exactly the same reasons we have to try to look * left before giving up.
*/
znode = left_znode(c, znode); if (!znode) return NULL; if (IS_ERR(znode)) return znode;
ubifs_search_zbranch(c, znode, key, &n);
ubifs_assert(c, n >= 0);
} if (znode->level == level + 1) break;
znode = get_znode(c, znode, n); if (IS_ERR(znode)) return znode;
} /* Check if the child is the one we are looking for */ if (znode->zbranch[n].lnum == lnum && znode->zbranch[n].offs == offs) return get_znode(c, znode, n); /* If the key is unique, there is nowhere else to look */ if (!is_hash_key(c, key)) return NULL; /* * The key is not unique and so may be also in the znodes to either * side.
*/
zn = znode;
nn = n; /* Look left */ while (1) { /* Move one branch to the left */ if (n)
n -= 1; else {
znode = left_znode(c, znode); if (!znode) break; if (IS_ERR(znode)) return znode;
n = znode->child_cnt - 1;
} /* Check it */ if (znode->zbranch[n].lnum == lnum &&
znode->zbranch[n].offs == offs) return get_znode(c, znode, n); /* Stop if the key is less than the one we are looking for */ if (keys_cmp(c, &znode->zbranch[n].key, key) < 0) break;
} /* Back to the middle */
znode = zn;
n = nn; /* Look right */ while (1) { /* Move one branch to the right */ if (++n >= znode->child_cnt) {
znode = right_znode(c, znode); if (!znode) break; if (IS_ERR(znode)) return znode;
n = 0;
} /* Check it */ if (znode->zbranch[n].lnum == lnum &&
znode->zbranch[n].offs == offs) return get_znode(c, znode, n); /* Stop if the key is greater than the one we are looking for */ if (keys_cmp(c, &znode->zbranch[n].key, key) > 0) break;
} return NULL;
}
/** * is_idx_node_in_tnc - determine if an index node is in the TNC. * @c: UBIFS file-system description object * @key: key of index node * @level: index node level * @lnum: LEB number of index node * @offs: offset of index node * * This function returns %0 if the index node is not referred to in the TNC, %1 * if the index node is referred to in the TNC and the corresponding znode is * dirty, %2 if an index node is referred to in the TNC and the corresponding * znode is clean, and a negative error code in case of failure. * * Note, the @key argument has to be the key of the first child. Also note, * this function relies on the fact that 0:0 is never a valid LEB number and * offset for a main-area node.
*/ int is_idx_node_in_tnc(struct ubifs_info *c, union ubifs_key *key, int level, int lnum, int offs)
{ struct ubifs_znode *znode;
znode = lookup_znode(c, key, level, lnum, offs); if (!znode) return 0; if (IS_ERR(znode)) return PTR_ERR(znode);
return ubifs_zn_dirty(znode) ? 1 : 2;
}
/** * is_leaf_node_in_tnc - determine if a non-indexing not is in the TNC. * @c: UBIFS file-system description object * @key: node key * @lnum: node LEB number * @offs: node offset * * This function returns %1 if the node is referred to in the TNC, %0 if it is * not, and a negative error code in case of failure. * * Note, this function relies on the fact that 0:0 is never a valid LEB number * and offset for a main-area node.
*/ staticint is_leaf_node_in_tnc(struct ubifs_info *c, union ubifs_key *key, int lnum, int offs)
{ struct ubifs_zbranch *zbr; struct ubifs_znode *znode, *zn; int n, found, err, nn; constint unique = !is_hash_key(c, key);
found = ubifs_lookup_level0(c, key, &znode, &n); if (found < 0) return found; /* Error code */ if (!found) return 0;
zbr = &znode->zbranch[n]; if (lnum == zbr->lnum && offs == zbr->offs) return 1; /* Found it */ if (unique) return 0; /* * Because the key is not unique, we have to look left * and right as well
*/
zn = znode;
nn = n; /* Look left */ while (1) {
err = tnc_prev(c, &znode, &n); if (err == -ENOENT) break; if (err) return err; if (keys_cmp(c, key, &znode->zbranch[n].key)) break;
zbr = &znode->zbranch[n]; if (lnum == zbr->lnum && offs == zbr->offs) return 1; /* Found it */
} /* Look right */
znode = zn;
n = nn; while (1) {
err = tnc_next(c, &znode, &n); if (err) { if (err == -ENOENT) return 0; return err;
} if (keys_cmp(c, key, &znode->zbranch[n].key)) break;
zbr = &znode->zbranch[n]; if (lnum == zbr->lnum && offs == zbr->offs) return 1; /* Found it */
} return 0;
}
/** * ubifs_tnc_has_node - determine whether a node is in the TNC. * @c: UBIFS file-system description object * @key: node key * @level: index node level (if it is an index node) * @lnum: node LEB number * @offs: node offset * @is_idx: non-zero if the node is an index node * * This function returns %1 if the node is in the TNC, %0 if it is not, and a * negative error code in case of failure. For index nodes, @key has to be the * key of the first child. An index node is considered to be in the TNC only if * the corresponding znode is clean or has not been loaded.
*/ int ubifs_tnc_has_node(struct ubifs_info *c, union ubifs_key *key, int level, int lnum, int offs, int is_idx)
{ int err;
mutex_lock(&c->tnc_mutex); if (is_idx) {
err = is_idx_node_in_tnc(c, key, level, lnum, offs); if (err < 0) goto out_unlock; if (err == 1) /* The index node was found but it was dirty */
err = 0; elseif (err == 2) /* The index node was found and it was clean */
err = 1; else
BUG_ON(err != 0);
} else
err = is_leaf_node_in_tnc(c, key, lnum, offs);
/** * ubifs_dirty_idx_node - dirty an index node. * @c: UBIFS file-system description object * @key: index node key * @level: index node level * @lnum: index node LEB number * @offs: index node offset * * This function loads and dirties an index node so that it can be garbage * collected. The @key argument has to be the key of the first child. This * function relies on the fact that 0:0 is never a valid LEB number and offset * for a main-area node. Returns %0 on success and a negative error code on * failure.
*/ int ubifs_dirty_idx_node(struct ubifs_info *c, union ubifs_key *key, int level, int lnum, int offs)
{ struct ubifs_znode *znode; int err = 0;
/** * dbg_check_inode_size - check if inode size is correct. * @c: UBIFS file-system description object * @inode: inode to check * @size: inode size * * This function makes sure that the inode size (@size) is correct and it does * not have any pages beyond @size. Returns zero if the inode is OK, %-EINVAL * if it has a data page beyond @size, and other negative error code in case of * other errors.
*/ int dbg_check_inode_size(struct ubifs_info *c, conststruct inode *inode,
loff_t size)
{ int err, n; union ubifs_key from_key, to_key, *key; struct ubifs_znode *znode; unsignedint block;
if (!S_ISREG(inode->i_mode)) return 0; if (!dbg_is_chk_gen(c)) return 0;
out_dump:
block = key_block(c, key);
ubifs_err(c, "inode %lu has size %lld, but there are data at offset %lld",
(unsignedlong)inode->i_ino, size,
((loff_t)block) << UBIFS_BLOCK_SHIFT);
mutex_unlock(&c->tnc_mutex);
ubifs_dump_inode(c, inode);
dump_stack(); return -EINVAL;
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