| /* |
| * 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 <linux/slab.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(!ubifs_zn_obsolete(znode)); |
| __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 (!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; |
| |
| 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. |
| * |
| * 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. |
| */ |
| 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 = ubifs_leb_read(c, lnum, buf, offs, len, 1); |
| 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; |
| |
| if (type == UBIFS_DATA_NODE && c->no_chk_data_crc && !c->mounting && |
| !c->remounting_rw) |
| return 1; |
| |
| 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 && c->replaying) |
| 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 (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 closest 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)); |
| ubifs_assert(key_type(c, key) < UBIFS_INVALID_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 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; |
| } |
| |
| /** |
| * 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. |
| */ |
| static int 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, const union 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; |
| } else if (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_node_nm(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, uninitialized_var(offs); |
| int uninitialized_var(len); |
| unsigned int 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; |
| unsigned int 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. |
| */ |
| static int read_wbuf(struct ubifs_wbuf *wbuf, void *buf, int len, int lnum, |
| int offs) |
| { |
| const struct ubifs_info *c = wbuf->c; |
| int rlen, overlap; |
| |
| dbg_io("LEB %d:%d, length %d", lnum, offs, len); |
| ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0); |
| ubifs_assert(!(offs & 7) && offs < c->leb_size); |
| ubifs_assert(offs + len <= c->leb_size); |
| |
| 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. |
| */ |
| static int 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("bad node type (%d but expected %d)", |
| ch->node_type, UBIFS_DATA_NODE); |
| goto out_err; |
| } |
| |
| err = ubifs_check_node(c, buf, zbr->lnum, zbr->offs, 0, 0); |
| if (err) { |
| ubifs_err("expected node type %d", UBIFS_DATA_NODE); |
| goto out; |
| } |
| |
| len = le32_to_cpu(ch->len); |
| if (len != zbr->len) { |
| ubifs_err("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("bad key in node at LEB %d:%d", |
| zbr->lnum, zbr->offs); |
| dbg_tnc("looked for key %s found node's key %s", |
| DBGKEY(&zbr->key), DBGKEY1(&key1)); |
| goto out_err; |
| } |
| |
| return 0; |
| |
| out_err: |
| err = -EINVAL; |
| out: |
| ubifs_err("bad node at LEB %d:%d", zbr->lnum, zbr->offs); |
| dbg_dump_node(c, buf); |
| dbg_dump_stack(); |
| return 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("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("failed to read from LEB %d:%d, error %d", |
| lnum, offs, err); |
| dbg_dump_stack(); |
| dbg_tnc("key %s", DBGKEY(&bu->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 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; |
| |
| 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; |
| } |
| |
| err = tnc_read_node_nm(c, &znode->zbranch[n], node); |
| |
| 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, *key1; |
| |
| 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 && key_type(c, key) == UBIFS_DATA_KEY) { |
| /* Try not to split consecutive data keys */ |
| if (n == c->fanout) { |
| key1 = &znode->zbranch[n - 1].key; |
| if (key_inum(c, key1) == key_inum(c, key) && |
| key_type(c, key1) == UBIFS_DATA_KEY) |
| appending = 1; |
| } else |
| goto check_split; |
| } else if (appending && n != c->fanout) { |
| /* Try not to split consecutive data keys */ |
| appending = 0; |
| check_split: |
| if (n >= (c->fanout + 1) / 2) { |
| key1 = &znode->zbranch[0].key; |
| if (key_inum(c, key1) == key_inum(c, key) && |
| key_type(c, key1) == UBIFS_DATA_KEY) { |
| key1 = &znode->zbranch[n].key; |
| if (key_inum(c, key1) != key_inum(c, key) || |
| key_type(c, key1) != UBIFS_DATA_KEY) { |
| keep = n; |
| move = c->fanout - keep; |
| zi = znode; |
| goto do_split; |
| } |
| } |
| } |
| } |
| |
| 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; |
| } |
| |
| do_split: |
| |
| __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) { |
| if (n == 0 && zi == znode && znode->iip == 0) |
| correct_parent_keys(c, znode); |
| |
| /* Locate insertion point */ |
| n = znode->iip + 1; |
| |
| /* 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(!ubifs_zn_obsolete(znode)); |
| 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(!ubifs_zn_obsolete(zp)); |
| ubifs_assert(ubifs_zn_dirty(zp)); |
| 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", (unsigned long)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, |
| (unsigned long)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 (ubifs_zn_obsolete(znode)) |
| 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) |
| { |
| tnc_destroy_cnext(c); |
| if (c->zroot.znode) { |
| long n; |
| |
| ubifs_destroy_tnc_subtree(c->zroot.znode); |
| n = atomic_long_read(&c->clean_zn_cnt); |
| atomic_long_sub(n, &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 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. |
| */ |
| 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; |
| |
| ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY); |
| |
| /* |
| * 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
|