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Diffstat (limited to '')
| -rw-r--r-- | fs/ubifs/tnc.c | 2956 |
1 files changed, 2956 insertions, 0 deletions
diff --git a/fs/ubifs/tnc.c b/fs/ubifs/tnc.c new file mode 100644 index 000000000000..e909f4a96443 --- /dev/null +++ b/fs/ubifs/tnc.c @@ -0,0 +1,2956 @@ +/* + * 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 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. + */ + +#include <linux/crc32.h> +#include "ubifs.h" + +/* + * 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, +}; + +/** + * 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. + */ +static int insert_old_idx(struct ubifs_info *c, int lnum, int offs) +{ + struct ubifs_old_idx *old_idx, *o; + struct rb_node **p, *parent = NULL; + + old_idx = kmalloc(sizeof(struct ubifs_old_idx), GFP_NOFS); + if (unlikely(!old_idx)) + return -ENOMEM; + old_idx->lnum = lnum; + old_idx->offs = offs; + + p = &c->old_idx.rb_node; + while (*p) { + parent = *p; + o = rb_entry(parent, struct ubifs_old_idx, rb); + if (lnum < o->lnum) + p = &(*p)->rb_left; + else if (lnum > o->lnum) + p = &(*p)->rb_right; + else if (offs < o->offs) + p = &(*p)->rb_left; + else if (offs > o->offs) + p = &(*p)->rb_right; + else { + ubifs_err("old idx added twice!"); + kfree(old_idx); + return 0; + } + } + rb_link_node(&old_idx->rb, parent, p); + rb_insert_color(&old_idx->rb, &c->old_idx); + return 0; +} + +/** + * 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. + */ +static int ins_clr_old_idx_znode(struct ubifs_info *c, + struct ubifs_znode *znode) +{ + int err; + + if (znode->parent) { + struct ubifs_zbranch *zbr; + + zbr = &znode->parent->zbranch[znode->iip]; + if (zbr->len) { + err = insert_old_idx(c, zbr->lnum, zbr->offs); + if (err) + return err; + zbr->lnum = 0; + zbr->offs = 0; + zbr->len = 0; + } + } else + if (c->zroot.len) { + err = insert_old_idx(c, c->zroot.lnum, c->zroot.offs); + if (err) + return err; + c->zroot.lnum = 0; + c->zroot.offs = 0; + c->zroot.len = 0; + } + return 0; +} + +/** + * 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 rb_node *this = c->old_idx.rb_node; + struct ubifs_old_idx *old_idx; + + while (this) { + if (this->rb_left) { + this = this->rb_left; + continue; + } else if (this->rb_right) { + this = this->rb_right; + continue; + } + old_idx = rb_entry(this, struct ubifs_old_idx, rb); + this = rb_parent(this); + if (this) { + if (this->rb_left == &old_idx->rb) + this->rb_left = NULL; + else + this->rb_right = NULL; + } + 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. + */ +static struct ubifs_znode *copy_znode(struct ubifs_info *c, + struct ubifs_znode *znode) +{ + struct ubifs_znode *zn; + + zn = kmalloc(c->max_znode_sz, GFP_NOFS); + if (unlikely(!zn)) + return ERR_PTR(-ENOMEM); + + memcpy(zn, znode, c->max_znode_sz); + zn->cnext = NULL; + __set_bit(DIRTY_ZNODE, &zn->flags); + __clear_bit(COW_ZNODE, &zn->flags); + + ubifs_assert(!test_bit(OBSOLETE_ZNODE, &znode->flags)); + __set_bit(OBSOLETE_ZNODE, &znode->flags); + + if (znode->level != 0) { + int i; + const int n = zn->child_cnt; + + /* The children now have new parent */ + for (i = 0; i < n; i++) { + struct ubifs_zbranch *zbr = &zn->zbranch[i]; + + if (zbr->znode) + zbr->znode->parent = zn; + } + } + + atomic_long_inc(&c->dirty_zn_cnt); + return zn; +} + +/** + * 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. + */ +static int 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); +} + +/** + * 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. + */ +static struct 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 (!test_bit(COW_ZNODE, &znode->flags)) { + /* 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 (unlikely(IS_ERR(zn))) + return zn; + + if (zbr->len) { + err = insert_old_idx(c, zbr->lnum, zbr->offs); + if (unlikely(err)) + return ERR_PTR(err); + err = add_idx_dirt(c, zbr->lnum, zbr->len); + } else + err = 0; + + zbr->znode = zn; + zbr->lnum = 0; + zbr->offs = 0; + zbr->len = 0; + + if (unlikely(err)) + return ERR_PTR(err); + 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. + */ +static int lnc_add(struct ubifs_info *c, struct ubifs_zbranch *zbr, + const void *node) +{ + int err; + void *lnc_node; + const struct ubifs_dent_node *dent = node; + + ubifs_assert(!zbr->leaf); + ubifs_assert(zbr->len != 0); + ubifs_assert(is_hash_key(c, &zbr->key)); + + err = ubifs_validate_entry(c, dent); + if (err) { + dbg_dump_stack(); + dbg_dump_node(c, dent); + return err; + } + + lnc_node = kmalloc(zbr->len, GFP_NOFS); + if (!lnc_node) + /* We don't have to have the cache, so no error */ + return 0; + + memcpy(lnc_node, node, zbr->len); + 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. + */ +static int lnc_add_directly(struct ubifs_info *c, struct ubifs_zbranch *zbr, + void *node) +{ + int err; + + ubifs_assert(!zbr->leaf); + ubifs_assert(zbr->len != 0); + + err = ubifs_validate_entry(c, node); + if (err) { + dbg_dump_stack(); + dbg_dump_node(c, node); + return err; + } + + zbr->leaf = node; + return 0; +} + +/** + * lnc_free - remove a leaf node from the leaf node cache. + * @zbr: zbranch of leaf node + * @node: leaf node + */ +static void lnc_free(struct ubifs_zbranch *zbr) +{ + if (!zbr->leaf) + return; + kfree(zbr->leaf); + zbr->leaf = NULL; +} + +/** + * tnc_read_node_nm - 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 negative error + * code in case of failure. + */ +static int tnc_read_node_nm(struct ubifs_info *c, struct ubifs_zbranch *zbr, + void *node) +{ + int err; + + ubifs_assert(is_hash_key(c, &zbr->key)); + + if (zbr->leaf) { + /* Read from the leaf node cache */ + ubifs_assert(zbr->len != 0); + memcpy(node, zbr->leaf, zbr->len); + return 0; + } + + 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 + * @len: node length (not aligned) + * @lnum: LEB number of node to read + * @offs: offset of 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. + */ +static int try_read_node(const struct ubifs_info *c, void *buf, int type, + int len, int lnum, int offs) +{ + int err, node_len; + struct ubifs_ch *ch = buf; + uint32_t crc, node_crc; + + dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len); + + err = ubi_read(c->ubi, lnum, buf, offs, len); + if (err) { + ubifs_err("cannot read node type %d from LEB %d:%d, error %d", + type, lnum, offs, err); + return err; + } + + if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC) + return 0; + + if (ch->node_type != type) + return 0; + + node_len = le32_to_cpu(ch->len); + if (node_len != len) + return 0; + + crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8); + node_crc = le32_to_cpu(ch->crc); + if (crc != node_crc) + return 0; + + return 1; +} + +/** + * 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. + */ +static int fallible_read_node(struct ubifs_info *c, const union ubifs_key *key, + struct ubifs_zbranch *zbr, void *node) +{ + int ret; + + dbg_tnc("LEB %d:%d, key %s", zbr->lnum, zbr->offs, DBGKEY(key)); + + ret = try_read_node(c, node, key_type(c, key), zbr->len, zbr->lnum, + zbr->offs); + 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) + dbg_mnt("dangling branch LEB %d:%d len %d, key %s", + zbr->lnum, zbr->offs, zbr->len, DBGKEY(key)); + 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. + */ +static int matches_name(struct ubifs_info *c, struct ubifs_zbranch *zbr, + const struct qstr *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; + + nlen = le16_to_cpu(dent->nlen); + err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len)); + if (err == 0) { + if (nlen == nm->len) + return NAME_MATCHES; + else if (nlen < nm->len) + return NAME_LESS; + else + return NAME_GREATER; + } else if (err < 0) + return NAME_LESS; + else + return NAME_GREATER; + +out_free: + kfree(dent); + return err; +} + +/** + * 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. + */ +static struct ubifs_znode *get_znode(struct ubifs_info *c, + struct ubifs_znode *znode, int n) +{ + struct ubifs_zbranch *zbr; + + zbr = &znode->zbranch[n]; + if (zbr->znode) + znode = zbr->znode; + else + znode = ubifs_load_znode(c, zbr, znode, n); + return znode; +} + +/** + * 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. + */ +static int 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. + */ +static int 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. + */ +static int resolve_collision(struct ubifs_info *c, const union ubifs_key *key, + struct ubifs_znode **zn, int *n, + const struct qstr *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(*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(0); + if (err == -ENOENT) + err = -EINVAL; + return err; + } + ubifs_assert(*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(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(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. + */ +static int fallible_matches_name(struct ubifs_info *c, + struct ubifs_zbranch *zbr, + const struct qstr *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(err == 1); + + err = lnc_add_directly(c, zbr, dent); + if (err) + goto out_free; + } else + dent = zbr->leaf; + + nlen = le16_to_cpu(dent->nlen); + err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len)); + if (err == 0) { + if (nlen == nm->len) + return NAME_MATCHES; + else if (nlen < nm->len) + return NAME_LESS; + else + return NAME_GREATER; + } else if (err < 0) + return NAME_LESS; + else + return NAME_GREATER; + +out_free: + kfree(dent); + return err; +} + +/** + * 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. + */ +static int fallible_resolve_collision(struct ubifs_info *c, + const union ubifs_key *key, + struct ubifs_znode **zn, int *n, + const struct qstr *nm, int adding) +{ + struct ubifs_znode *o_znode = NULL, *znode = *zn; + int uninitialized_var(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; + } else if (!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(*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(0); + if (err == -ENOENT) + err = -EINVAL; + return err; + } + ubifs_assert(*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; + + dbg_mnt("dangling match LEB %d:%d len %d %s", + o_znode->zbranch[o_n].lnum, o_znode->zbranch[o_n].offs, + o_znode->zbranch[o_n].len, DBGKEY(key)); + *zn = o_znode; + *n = o_n; + return 1; +} + +/** + * 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. + */ +static int 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. + */ +static int resolve_collision_directly(struct ubifs_info *c, + const union 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. + */ +static struct 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->zroot.znode); + ubifs_assert(znode); + if (c->zroot.znode->level > BOTTOM_UP_HEIGHT) { + kfree(c->bottom_up_buf); + c->bottom_up_buf = kmalloc(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(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; + + zp = znode->parent; + if (zp) { + ubifs_assert(path[p - 1] >= 0); + ubifs_assert(path[p - 1] < zp->child_cnt); + zbr = &zp->zbranch[path[--p]]; + znode = dirty_cow_znode(c, zbr); + } else { + ubifs_assert(znode == c->zroot.znode); + znode = dirty_cow_znode(c, &c->zroot); + } + if (unlikely(IS_ERR(znode)) || !p) + break; + ubifs_assert(path[p - 1] >= 0); + ubifs_assert(path[p - 1] < znode->child_cnt); + znode = znode->zbranch[path[p - 1]].znode; + } + + return znode; +} + +/** + * 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 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 %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, const union ubifs_key *key, + struct ubifs_znode **zn, int *n) +{ + int err, exact; + struct ubifs_znode *znode; + unsigned long time = get_seconds(); + + dbg_tnc("search key %s", DBGKEY(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->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 = zbr->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); + } + + *zn = znode; + if (exact || !is_hash_key(c, key) || *n != -1) { + dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n); + return exact; + } + + /* + * 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 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; + } + + dbg_tnc("found 1, lvl %d, n %d", znode->level, *n); + *zn = znode; + return 1; +} + +/** + * 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. + */ +static int lookup_level0_dirty(struct ubifs_info *c, const union ubifs_key *key, + struct ubifs_znode **zn, int *n) +{ + int err, exact; + struct ubifs_znode *znode; + unsigned long time = get_seconds(); + + dbg_tnc("search and dirty key %s", DBGKEY(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); + } + + *zn = znode; + if (exact || !is_hash_key(c, key) || *n != -1) { + dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n); + return exact; + } + + /* + * See huge comment at 'lookup_level0_dirty()' what is the rest of the + * code. + */ + err = tnc_prev(c, &znode, n); + if (err == -ENOENT) { + *n = -1; + dbg_tnc("found 0, lvl %d, n -1", znode->level); + return 0; + } + if (unlikely(err < 0)) + return err; + if (keys_cmp(c, key, &znode->zbranch[*n].key)) { + *n = -1; + dbg_tnc("found 0, lvl %d, n -1", znode->level); + return 0; + } + + if (znode->cnext || !ubifs_zn_dirty(znode)) { + znode = dirty_cow_bottom_up(c, znode); + if (IS_ERR(znode)) + return PTR_ERR(znode); + } + + dbg_tnc("found 1, lvl %d, n %d", znode->level, *n); + *zn = znode; + return 1; +} + +/** + * ubifs_tnc_lookup - look up a file-system node. + * @c: UBIFS file-system description object + * @key: node key to lookup + * @node: the node is returned here + * + * This function look 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. + */ +int ubifs_tnc_lookup(struct ubifs_info *c, const union ubifs_key *key, + void *node) +{ + int found, n, err; + struct ubifs_znode *znode; + struct ubifs_zbranch zbr, *zt; + + mutex_lock(&c->tnc_mutex); + found = ubifs_lookup_level0(c, key, &znode, &n); + if (!found) { + err = -ENOENT; + goto out; + } else if (found < 0) { + err = found; + goto out; + } + zt = &znode->zbranch[n]; + 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_node_nm(c, zt, node); + goto out; + } + zbr = znode->zbranch[n]; + mutex_unlock(&c->tnc_mutex); + + err = ubifs_tnc_read_node(c, &zbr, node); + return err; + +out: + mutex_unlock(&c->tnc_mutex); + return err; +} + +/** + * 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 is the same as 'ubifs_tnc_lookup()' but it returns the node + * location also. See 'ubifs_tnc_lookup()'. + */ +int ubifs_tnc_locate(struct ubifs_info *c, const union ubifs_key *key, + void *node, int *lnum, int *offs) +{ + int found, n, err; + struct ubifs_znode *znode; + struct ubifs_zbranch zbr, *zt; + + mutex_lock(&c->tnc_mutex); + found = ubifs_lookup_level0(c, key, &znode, &n); + if (!found) { + err = -ENOENT; + goto out; + } else if (found < 0) { + err = found; + goto out; + } + zt = &znode->zbranch[n]; + 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 + */ + *lnum = zt->lnum; + *offs = zt->offs; + err = tnc_read_node_nm(c, zt, node); + goto out; + } + zbr = znode->zbranch[n]; + mutex_unlock(&c->tnc_mutex); + + *lnum = zbr.lnum; + *offs = zbr.offs; + + err = ubifs_tnc_read_node(c, &zbr, node); + return err; + +out: + mutex_unlock(&c->tnc_mutex); + return err; +} + +/** + * 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 look 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. + */ +static int do_lookup_nm(struct ubifs_info *c, const union ubifs_key *key, + void *node, const struct qstr *nm) +{ + int found, n, err; + struct ubifs_znode *znode; + struct ubifs_zbranch zbr; + + dbg_tnc("name '%.*s' key %s", nm->len, nm->name, DBGKEY(key)); + mutex_lock(&c->tnc_mutex); + found = ubifs_lookup_level0(c, key, &znode, &n); + if (!found) { + err = -ENOENT; + goto out_unlock; + } else if (found < 0) { + err = found; + goto out_unlock; + } + + ubifs_assert(n >= 0); + + 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; + if (err == 0) { + err = -ENOENT; + goto out_unlock; + } + + zbr = znode->zbranch[n]; + mutex_unlock(&c->tnc_mutex); + + err = tnc_read_node_nm(c, &zbr, node); + return err; + +out_unlock: + mutex_unlock(&c->tnc_mutex); + return err; +} + +/** + * 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 look 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, const union ubifs_key *key, + void *node, const struct qstr *nm) +{ + int err, len; + const struct 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 (nm->len == len && !memcmp(dent->name, nm->name, 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); +} + +/** + * 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. + */ +static void correct_parent_keys(const struct ubifs_info *c, + struct ubifs_znode *znode) +{ + union ubifs_key *key, *key1; + + ubifs_assert(znode->parent); + ubifs_assert(znode->iip == 0); + + key = &znode->zbranch[0].key; + key1 = &znode->parent->zbranch[0].key; + + while (keys_cmp(c, key, key1) < 0) { + key_copy(c, key, key1); + znode = znode->parent; + znode->alt = 1; + if (!znode->parent || znode->iip) + break; + key1 = &znode->parent->zbranch[0].key; + } +} + +/** + * insert_zbranch - insert a zbranch into a znode. + * @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. + */ +static void insert_zbranch(struct ubifs_znode *znode, + const struct ubifs_zbranch *zbr, int n) +{ + int i; + + ubifs_assert(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. + */ +static int 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; + + ubifs_assert(n >= 0 && n <= c->fanout); + + /* Implement naive insert for now */ +again: + zp = znode->parent; + if (znode->child_cnt < c->fanout) { + ubifs_assert(n != c->fanout); + dbg_tnc("inserted at %d level %d, key %s", n, znode->level, + DBGKEY(key)); + + insert_zbranch(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_tnc("splitting level %d, key %s", znode->level, DBGKEY(key)); + + 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); + + zn = kzalloc(c->max_znode_sz, GFP_NOFS); + if (!zn) + return -ENOMEM; + zn->parent = zp; + zn->level = znode->level; + + /* Decide where to split */ + if (znode->level == 0 && n == c->fanout && + key_type(c, key) == UBIFS_DATA_KEY) { + union ubifs_key *key1; + + /* + * If this is an inode which is being appended - do not split + * it because no other zbranches can be inserted between + * zbranches of consecutive data nodes anyway. + */ + key1 = &znode->zbranch[n - 1].key; + if (key_inum(c, key1) == key_inum(c, key) && + key_type(c, key1) == UBIFS_DATA_KEY && + key_block(c, key1) == key_block(c, key) - 1) + appending = 1; + } + + if (appending) { + keep = c->fanout; + move = 0; + } else { + keep = (c->fanout + 1) / 2; + move = c->fanout - keep; + } + + /* + * Although we don't at present, we could look at the neighbors and see + * if we can move some zbranches there. + */ + + if (n < keep) { + /* Insert into existing znode */ + zi = znode; + move += 1; + keep -= 1; + } else { + /* Insert into new znode */ + zi = zn; + n -= keep; + /* Re-parent */ + if (zn->level != 0) + zbr->znode->parent = zn; + } + + __set_bit(DIRTY_ZNODE, &zn->flags); + atomic_long_inc(&c->dirty_zn_cnt); + + zn->child_cnt = move; + znode->child_cnt = keep; + + dbg_tnc("moving %d, keeping %d", move, keep); + + /* Move zbranch */ + for (i = 0; i < move; i++) { + zn->zbranch[i] = znode->zbranch[keep + i]; + /* Re-parent */ + if (zn->level != 0) + if (zn->zbranch[i].znode) { + zn->zbranch[i].znode->parent = zn; + zn->zbranch[i].znode->iip = i; + } + } + + /* Insert new key and branch */ + dbg_tnc("inserting at %d level %d, key %s", n, zn->level, DBGKEY(key)); + + insert_zbranch(zi, zbr, n); + + /* Insert new znode (produced by spitting) into the parent */ + if (zp) { + i = n; + /* Locate insertion point */ + n = znode->iip + 1; + if (appending && n != c->fanout) + appending = 0; + + if (i == 0 && zi == znode && znode->iip == 0) + correct_parent_keys(c, znode); + + /* Tail recursion */ + zbr->key = zn->zbranch[0].key; + zbr->znode = zn; + zbr->lnum = 0; + zbr->offs = 0; + zbr->len = 0; + znode = zp; + + goto again; + } + + /* We have to split root znode */ + dbg_tnc("creating new zroot at level %d", znode->level + 1); + + zi = kzalloc(c->max_znode_sz, GFP_NOFS); + if (!zi) + return -ENOMEM; + + zi->child_cnt = 2; + zi->level = znode->level + 1; + + __set_bit(DIRTY_ZNODE, &zi->flags); + atomic_long_inc(&c->dirty_zn_cnt); + + zi->zbranch[0].key = znode->zbranch[0].key; + zi->zbranch[0].znode = znode; + zi->zbranch[0].lnum = c->zroot.lnum; + zi->zbranch[0].offs = c->zroot.offs; + zi->zbranch[0].len = c->zroot.len; + zi->zbranch[1].key = zn->zbranch[0].key; + zi->zbranch[1].znode = zn; + + c->zroot.lnum = 0; + c->zroot.offs = 0; + c->zroot.len = 0; + c->zroot.znode = zi; + + zn->parent = zi; + zn->iip = 1; + znode->parent = zi; + znode->iip = 0; + + return 0; +} + +/** + * 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 + * + * 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, const union ubifs_key *key, int lnum, + int offs, int len) +{ + int found, n, err = 0; + struct ubifs_znode *znode; + + mutex_lock(&c->tnc_mutex); + dbg_tnc("%d:%d, len %d, key %s", lnum, offs, len, DBGKEY(key)); + found = lookup_level0_dirty(c, key, &znode, &n); + if (!found) { + struct ubifs_zbranch zbr; + + zbr.znode = NULL; + zbr.lnum = lnum; + zbr.offs = offs; + zbr.len = len; + key_copy(c, key, &zbr.key); + err = tnc_insert(c, znode, &zbr, n + 1); + } else if (found == 1) { + struct ubifs_zbranch *zbr = &znode->zbranch[n]; + + lnc_free(zbr); + err = ubifs_add_dirt(c, zbr->lnum, zbr->len); + zbr->lnum = lnum; + zbr->offs = offs; + zbr->len = len; + } else + err = found; + if (!err) + err = dbg_check_tnc(c, 0); + mutex_unlock(&c->tnc_mutex); + + return err; +} + +/** + * 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, const union 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_tnc("old LEB %d:%d, new LEB %d:%d, len %d, key %s", old_lnum, + old_offs, lnum, offs, len, DBGKEY(key)); + 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; + } else if (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; + } + } + } + + if (!found) + err = ubifs_add_dirt(c, lnum, len); + + if (!err) + err = dbg_check_tnc(c, 0); + +out_unlock: + mutex_unlock(&c->tnc_mutex); + return err; +} + +/** + * 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 + * @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, const union ubifs_key *key, + int lnum, int offs, int len, const struct qstr *nm) +{ + int found, n, err = 0; + struct ubifs_znode *znode; + + mutex_lock(&c->tnc_mutex); + dbg_tnc("LEB %d:%d, name '%.*s', key %s", lnum, offs, nm->len, nm->name, + DBGKEY(key)); + found = lookup_level0_dirty(c, key, &znode, &n); + if (found < 0) { + err = found; + goto out_unlock; + } + + if (found == 1) { + if (c->replaying) + found = fallible_resolve_collision(c, key, &znode, &n, + nm, 1); + else + found = resolve_collision(c, key, &znode, &n, nm); + dbg_tnc("rc returned %d, znode %p, n %d", found, znode, n); + if (found < 0) { + err = found; + 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; + } + } + + if (found == 1) { + struct ubifs_zbranch *zbr = &znode->zbranch[n]; + + lnc_free(zbr); + err = ubifs_add_dirt(c, zbr->lnum, zbr->len); + zbr->lnum = lnum; + zbr->offs = offs; + zbr->len = len; + goto out_unlock; + } + } + + if (!found) { + struct ubifs_zbranch zbr; + + zbr.znode = NULL; + zbr.lnum = lnum; + zbr.offs = offs; + zbr.len = len; + 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 qstr noname = { .len = 0, .name = "" }; + + err = dbg_check_tnc(c, 0); + mutex_unlock(&c->tnc_mutex); + if (err) + return err; + return ubifs_tnc_remove_nm(c, key, &noname); + } + } + +out_unlock: + if (!err) + err = dbg_check_tnc(c, 0); + mutex_unlock(&c->tnc_mutex); + return err; +} + +/** + * 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. + */ +static int 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(znode->level == 0); + ubifs_assert(n >= 0 && n < c->fanout); + dbg_tnc("deleting %s", DBGKEY(&znode->zbranch[n].key)); + + zbr = &znode->zbranch[n]; + lnc_free(zbr); + + err = ubifs_add_dirt(c, zbr->lnum, zbr->len); + if (err) { + dbg_dump_znode(c, znode); + return err; + } + + /* We do not "gap" zbranch slots */ + for (i = n; i < znode->child_cnt - 1; i++) + znode->zbranch[i] = znode->zbranch[i + 1]; + znode->child_cnt -= 1; + + if (znode->child_cnt > 0) + return 0; + + /* + * This was the last zbranch, we have to delete this znode from the + * parent. + */ + + do { + ubifs_assert(!test_bit(OBSOLETE_ZNODE, &znode->flags)); + ubifs_assert(ubifs_zn_dirty(znode)); + + zp = znode->parent; + n = znode->iip; + + atomic_long_dec(&c->dirty_zn_cnt); + + err = insert_old_idx_znode(c, znode); + if (err) + return err; + + if (znode->cnext) { + __set_bit(OBSOLETE_ZNODE, &znode->flags); + atomic_long_inc(&c->clean_zn_cnt); + atomic_long_inc(&ubifs_clean_zn_cnt); + } else + kfree(znode); + znode = zp; + } while (znode->child_cnt == 1); /* while removing last child */ + + /* Remove from znode, entry n - 1 */ + znode->child_cnt -= 1; + ubifs_assert(znode->level != 0); + for (i = n; i < znode->child_cnt; i++) { + znode->zbranch[i] = znode->zbranch[i + 1]; + if (znode->zbranch[i].znode) + znode->zbranch[i].znode->iip = i; + } + + /* + * If this is the root and it has only 1 child then + * collapse the tree. + */ + if (!znode->parent) { + while (znode->child_cnt == 1 && znode->level != 0) { + zp = znode; + zbr = &znode->zbranch[0]; + znode = get_znode(c, znode, 0); + if (IS_ERR(znode)) + return PTR_ERR(znode); + znode = dirty_cow_znode(c, zbr); + if (IS_ERR(znode)) + return PTR_ERR(znode); + znode->parent = NULL; + znode->iip = 0; + if (c->zroot.len) { + err = insert_old_idx(c, c->zroot.lnum, + c->zroot.offs); + if (err) + return err; + } + c->zroot.lnum = zbr->lnum; + c->zroot.offs = zbr->offs; + c->zroot.len = zbr->len; + c->zroot.znode = znode; + ubifs_assert(!test_bit(OBSOLETE_ZNODE, + &zp->flags)); + ubifs_assert(test_bit(DIRTY_ZNODE, &zp->flags)); + atomic_long_dec(&c->dirty_zn_cnt); + + if (zp->cnext) { + __set_bit(OBSOLETE_ZNODE, &zp->flags); + atomic_long_inc(&c->clean_zn_cnt); + atomic_long_inc(&ubifs_clean_zn_cnt); + } else + kfree(zp); + } + } + + return 0; +} + +/** + * 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, const union ubifs_key *key) +{ + int found, n, err = 0; + struct ubifs_znode *znode; + + mutex_lock(&c->tnc_mutex); + dbg_tnc("key %s", DBGKEY(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); + +out_unlock: + mutex_unlock(&c->tnc_mutex); + return err; +} + +/** + * 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, const union ubifs_key *key, + const struct qstr *nm) +{ + int n, err; + struct ubifs_znode *znode; + + mutex_lock(&c->tnc_mutex); + dbg_tnc("%.*s, key %s", nm->len, nm->name, DBGKEY(key)); + err = lookup_level0_dirty(c, key, &znode, &n); + if (err < 0) + goto out_unlock; + + if (err) { + 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 (err < 0) + goto out_unlock; + if (err) { + /* 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; + } + } + err = tnc_delete(c, znode, n); + } + } + +out_unlock: + if (!err) + err = dbg_check_tnc(c, 0); + mutex_unlock(&c->tnc_mutex); + return err; +} + +/** + * 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. + */ +static int 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; + + if (err) + key = from_key; + else { + err = tnc_next(c, &znode, &n); + if (err == -ENOENT) { + err = 0; + goto out_unlock; + } + if (err < 0) + goto out_unlock; + key = &znode->zbranch[n].key; + if (!key_in_range(c, key, from_key, to_key)) { + 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) { + dbg_dump_znode(c, znode); + goto out_unlock; + } + dbg_tnc("removing %s", DBGKEY(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; + } + +out_unlock: + if (!err) + err = dbg_check_tnc(c, 0); + mutex_unlock(&c->tnc_mutex); + return err; +} + +/** + * 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 qstr nm = { .name = NULL }; + + dbg_tnc("ino %lu", 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; + return err; + } + + xattr_inum = le64_to_cpu(xent->inum); + dbg_tnc("xent '%s', ino %lu", xent->name, xattr_inum); + + nm.name = xent->name; + nm.len = le16_to_cpu(xent->nlen); + err = ubifs_tnc_remove_nm(c, &key1, &nm); + if (err) { + kfree(xent); + return err; + } + + lowest_ino_key(c, &key1, xattr_inum); + highest_ino_key(c, &key2, xattr_inum); + err = ubifs_tnc_remove_range(c, &key1, &key2); + if (err) { + kfree(xent); + return err; + } + + kfree(pxent); + pxent = xent; + key_read(c, &xent->key, &key1); + } + + kfree(pxent); + lowest_ino_key(c, &key1, inum); + highest_ino_key(c, &key2, inum); + + return ubifs_tnc_remove_range(c, &key1, &key2); +} + +/** + * 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, + const struct qstr *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; + + dbg_tnc("%s %s", nm->name ? (char *)nm->name : "(lowest)", DBGKEY(key)); + ubifs_assert(is_hash_key(c, key)); + + mutex_lock(&c->tnc_mutex); + err = ubifs_lookup_level0(c, key, &znode, &n); + if (unlikely(err < 0)) + goto out_unlock; + + if (nm->name) { + if (err) { + /* Handle collisions */ + 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; + } + } + + zbr = &znode->zbranch[n]; + dent = kmalloc(zbr->len, GFP_NOFS); + if (unlikely(!dent)) { + err = -ENOMEM; + 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_node_nm(c, zbr, dent); + if (unlikely(err)) + goto out_free; + + mutex_unlock(&c->tnc_mutex); + return dent; + +out_free: + kfree(dent); +out_unlock: + mutex_unlock(&c->tnc_mutex); + return ERR_PTR(err); +} + +/** + * 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. + */ +static void tnc_destroy_cnext(struct ubifs_info *c) +{ + struct ubifs_znode *cnext; + + if (!c->cnext) + return; + ubifs_assert(c->cmt_state == COMMIT_BROKEN); + cnext = c->cnext; + do { + struct ubifs_znode *znode = cnext; + + cnext = cnext->cnext; + if (test_bit(OBSOLETE_ZNODE, &znode->flags)) + kfree(znode); + } 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) +{ + long clean_freed; + + tnc_destroy_cnext(c); + if (c->zroot.znode) { + clean_freed = ubifs_destroy_tnc_subtree(c->zroot.znode); + atomic_long_sub(clean_freed, &ubifs_clean_zn_cnt); + } + 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. + */ +static struct 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. + */ +static struct 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 fro 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. + */ +static struct 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(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. + */ +static int 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; + const int 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; + else if (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); + +out_unlock: + mutex_unlock(&c->tnc_mutex); + return err; +} + +/** + * 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; + + mutex_lock(&c->tnc_mutex); + znode = lookup_znode(c, key, level, lnum, offs); + if (!znode) + goto out_unlock; + if (IS_ERR(znode)) { + err = PTR_ERR(znode); + goto out_unlock; + } + znode = dirty_cow_bottom_up(c, znode); + if (IS_ERR(znode)) { + err = PTR_ERR(znode); + goto out_unlock; + } + +out_unlock: + mutex_unlock(&c->tnc_mutex); + return err; +} |