UBIFS: add new flash file system

This is a new flash file system. See
http://www.linux-mtd.infradead.org/doc/ubifs.html

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>

1 files changed, 494 insertions, 0 deletions

diff --git a/fs/ubifs/tnc_misc.c b/fs/ubifs/tnc_misc.c
new file mode 100644
index 000000000000..a25c1cc1f8d9
--- /dev/null
+++ b/fs/ubifs/tnc_misc.c
@@ -0,0 +1,494 @@
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * Authors: Adrian Hunter
+ *          Artem Bityutskiy (Битюцкий Артём)
+ */
+
+/*
+ * This file contains miscelanious TNC-related functions shared betweend
+ * different files. This file does not form any logically separate TNC
+ * sub-system. The file was created because there is a lot of TNC code and
+ * putting it all in one file would make that file too big and unreadable.
+ */
+
+#include "ubifs.h"
+
+/**
+ * ubifs_tnc_levelorder_next - next TNC tree element in levelorder traversal.
+ * @zr: root of the subtree to traverse
+ * @znode: previous znode
+ *
+ * This function implements levelorder TNC traversal. The LNC is ignored.
+ * Returns the next element or %NULL if @znode is already the last one.
+ */
+struct ubifs_znode *ubifs_tnc_levelorder_next(struct ubifs_znode *zr,
+                                              struct ubifs_znode *znode)
+{
+        int level, iip, level_search = 0;
+        struct ubifs_znode *zn;
+
+        ubifs_assert(zr);
+
+        if (unlikely(!znode))
+                return zr;
+
+        if (unlikely(znode == zr)) {
+                if (znode->level == 0)
+                        return NULL;
+                return ubifs_tnc_find_child(zr, 0);
+        }
+
+        level = znode->level;
+
+        iip = znode->iip;
+        while (1) {
+                ubifs_assert(znode->level <= zr->level);
+
+                /*
+                 * First walk up until there is a znode with next branch to
+                 * look at.
+                 */
+                while (znode->parent != zr && iip >= znode->parent->child_cnt) {
+                        znode = znode->parent;
+                        iip = znode->iip;
+                }
+
+                if (unlikely(znode->parent == zr &&
+                             iip >= znode->parent->child_cnt)) {
+                        /* This level is done, switch to the lower one */
+                        level -= 1;
+                        if (level_search || level < 0)
+                                /*
+                                 * We were already looking for znode at lower
+                                 * level ('level_search'). As we are here
+                                 * again, it just does not exist. Or all levels
+                                 * were finished ('level < 0').
+                                 */
+                                return NULL;
+
+                        level_search = 1;
+                        iip = -1;
+                        znode = ubifs_tnc_find_child(zr, 0);
+                        ubifs_assert(znode);
+                }
+
+                /* Switch to the next index */
+                zn = ubifs_tnc_find_child(znode->parent, iip + 1);
+                if (!zn) {
+                        /* No more children to look at, we have walk up */
+                        iip = znode->parent->child_cnt;
+                        continue;
+                }
+
+                /* Walk back down to the level we came from ('level') */
+                while (zn->level != level) {
+                        znode = zn;
+                        zn = ubifs_tnc_find_child(zn, 0);
+                        if (!zn) {
+                                /*
+                                 * This path is not too deep so it does not
+                                 * reach 'level'. Try next path.
+                                 */
+                                iip = znode->iip;
+                                break;
+                        }
+                }
+
+                if (zn) {
+                        ubifs_assert(zn->level >= 0);
+                        return zn;
+                }
+        }
+}
+
+/**
+ * ubifs_search_zbranch - search znode branch.
+ * @c: UBIFS file-system description object
+ * @znode: znode to search in
+ * @key: key to search for
+ * @n: znode branch slot number is returned here
+ *
+ * This is a helper function which search branch with key @key in @znode using
+ * binary search. The result of the search may be:
+ *   o exact match, then %1 is returned, and the slot number of the branch is
+ *     stored in @n;
+ *   o no exact match, then %0 is returned and the slot number of the left
+ *     closest branch is returned in @n; the slot if all keys in this znode are
+ *     greater than @key, then %-1 is returned in @n.
+ */
+int ubifs_search_zbranch(const struct ubifs_info *c,
+                         const struct ubifs_znode *znode,
+                         const union ubifs_key *key, int *n)
+{
+        int beg = 0, end = znode->child_cnt, uninitialized_var(mid);
+        int uninitialized_var(cmp);
+        const struct ubifs_zbranch *zbr = &znode->zbranch[0];
+
+        ubifs_assert(end > beg);
+
+        while (end > beg) {
+                mid = (beg + end) >> 1;
+                cmp = keys_cmp(c, key, &zbr[mid].key);
+                if (cmp > 0)
+                        beg = mid + 1;
+                else if (cmp < 0)
+                        end = mid;
+                else {
+                        *n = mid;
+                        return 1;
+                }
+        }
+
+        *n = end - 1;
+
+        /* The insert point is after *n */
+        ubifs_assert(*n >= -1 && *n < znode->child_cnt);
+        if (*n == -1)
+                ubifs_assert(keys_cmp(c, key, &zbr[0].key) < 0);
+        else
+                ubifs_assert(keys_cmp(c, key, &zbr[*n].key) > 0);
+        if (*n + 1 < znode->child_cnt)
+                ubifs_assert(keys_cmp(c, key, &zbr[*n + 1].key) < 0);
+
+        return 0;
+}
+
+/**
+ * ubifs_tnc_postorder_first - find first znode to do postorder tree traversal.
+ * @znode: znode to start at (root of the sub-tree to traverse)
+ *
+ * Find the lowest leftmost znode in a subtree of the TNC tree. The LNC is
+ * ignored.
+ */
+struct ubifs_znode *ubifs_tnc_postorder_first(struct ubifs_znode *znode)
+{
+        if (unlikely(!znode))
+                return NULL;
+
+        while (znode->level > 0) {
+                struct ubifs_znode *child;
+
+                child = ubifs_tnc_find_child(znode, 0);
+                if (!child)
+                        return znode;
+                znode = child;
+        }
+
+        return znode;
+}
+
+/**
+ * ubifs_tnc_postorder_next - next TNC tree element in postorder traversal.
+ * @znode: previous znode
+ *
+ * This function implements postorder TNC traversal. The LNC is ignored.
+ * Returns the next element or %NULL if @znode is already the last one.
+ */
+struct ubifs_znode *ubifs_tnc_postorder_next(struct ubifs_znode *znode)
+{
+        struct ubifs_znode *zn;
+
+        ubifs_assert(znode);
+        if (unlikely(!znode->parent))
+                return NULL;
+
+        /* Switch to the next index in the parent */
+        zn = ubifs_tnc_find_child(znode->parent, znode->iip + 1);
+        if (!zn)
+                /* This is in fact the last child, return parent */
+                return znode->parent;
+
+        /* Go to the first znode in this new subtree */
+        return ubifs_tnc_postorder_first(zn);
+}
+
+/**
+ * ubifs_destroy_tnc_subtree - destroy all znodes connected to a subtree.
+ * @znode: znode defining subtree to destroy
+ *
+ * This function destroys subtree of the TNC tree. Returns number of clean
+ * znodes in the subtree.
+ */
+long ubifs_destroy_tnc_subtree(struct ubifs_znode *znode)
+{
+        struct ubifs_znode *zn = ubifs_tnc_postorder_first(znode);
+        long clean_freed = 0;
+        int n;
+
+        ubifs_assert(zn);
+        while (1) {
+                for (n = 0; n < zn->child_cnt; n++) {
+                        if (!zn->zbranch[n].znode)
+                                continue;
+
+                        if (zn->level > 0 &&
+                            !ubifs_zn_dirty(zn->zbranch[n].znode))
+                                clean_freed += 1;
+
+                        cond_resched();
+                        kfree(zn->zbranch[n].znode);
+                }
+
+                if (zn == znode) {
+                        if (!ubifs_zn_dirty(zn))
+                                clean_freed += 1;
+                        kfree(zn);
+                        return clean_freed;
+                }
+
+                zn = ubifs_tnc_postorder_next(zn);
+        }
+}
+
+/**
+ * read_znode - read an indexing node from flash and fill znode.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB of the indexing node to read
+ * @offs: node offset
+ * @len: node length
+ * @znode: znode to read to
+ *
+ * This function reads an indexing node from the flash media and fills znode
+ * with the read data. Returns zero in case of success and a negative error
+ * code in case of failure. The read indexing node is validated and if anything
+ * is wrong with it, this function prints complaint messages and returns
+ * %-EINVAL.
+ */
+static int read_znode(struct ubifs_info *c, int lnum, int offs, int len,
+                      struct ubifs_znode *znode)
+{
+        int i, err, type, cmp;
+        struct ubifs_idx_node *idx;
+
+        idx = kmalloc(c->max_idx_node_sz, GFP_NOFS);
+        if (!idx)
+                return -ENOMEM;
+
+        err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs);
+        if (err < 0) {
+                kfree(idx);
+                return err;
+        }
+
+        znode->child_cnt = le16_to_cpu(idx->child_cnt);
+        znode->level = le16_to_cpu(idx->level);
+
+        dbg_tnc("LEB %d:%d, level %d, %d branch",
+                lnum, offs, znode->level, znode->child_cnt);
+
+        if (znode->child_cnt > c->fanout || znode->level > UBIFS_MAX_LEVELS) {
+                dbg_err("current fanout %d, branch count %d",
+                        c->fanout, znode->child_cnt);
+                dbg_err("max levels %d, znode level %d",
+                        UBIFS_MAX_LEVELS, znode->level);
+                err = 1;
+                goto out_dump;
+        }
+
+        for (i = 0; i < znode->child_cnt; i++) {
+                const struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);
+                struct ubifs_zbranch *zbr = &znode->zbranch[i];
+
+                key_read(c, &br->key, &zbr->key);
+                zbr->lnum = le32_to_cpu(br->lnum);
+                zbr->offs = le32_to_cpu(br->offs);
+                zbr->len  = le32_to_cpu(br->len);
+                zbr->znode = NULL;
+
+                /* Validate branch */
+
+                if (zbr->lnum < c->main_first ||
+                    zbr->lnum >= c->leb_cnt || zbr->offs < 0 ||
+                    zbr->offs + zbr->len > c->leb_size || zbr->offs & 7) {
+                        dbg_err("bad branch %d", i);
+                        err = 2;
+                        goto out_dump;
+                }
+
+                switch (key_type(c, &zbr->key)) {
+                case UBIFS_INO_KEY:
+                case UBIFS_DATA_KEY:
+                case UBIFS_DENT_KEY:
+                case UBIFS_XENT_KEY:
+                        break;
+                default:
+                        dbg_msg("bad key type at slot %d: %s", i,
+                                DBGKEY(&zbr->key));
+                        err = 3;
+                        goto out_dump;
+                }
+
+                if (znode->level)
+                        continue;
+
+                type = key_type(c, &zbr->key);
+                if (c->ranges[type].max_len == 0) {
+                        if (zbr->len != c->ranges[type].len) {
+                                dbg_err("bad target node (type %d) length (%d)",
+                                        type, zbr->len);
+                                dbg_err("have to be %d", c->ranges[type].len);
+                                err = 4;
+                                goto out_dump;
+                        }
+                } else if (zbr->len < c->ranges[type].min_len ||
+                           zbr->len > c->ranges[type].max_len) {
+                        dbg_err("bad target node (type %d) length (%d)",
+                                type, zbr->len);
+                        dbg_err("have to be in range of %d-%d",
+                                c->ranges[type].min_len,
+                                c->ranges[type].max_len);
+                        err = 5;
+                        goto out_dump;
+                }
+        }
+
+        /*
+         * Ensure that the next key is greater or equivalent to the
+         * previous one.
+         */
+        for (i = 0; i < znode->child_cnt - 1; i++) {
+                const union ubifs_key *key1, *key2;
+
+                key1 = &znode->zbranch[i].key;
+                key2 = &znode->zbranch[i + 1].key;
+
+                cmp = keys_cmp(c, key1, key2);
+                if (cmp > 0) {
+                        dbg_err("bad key order (keys %d and %d)", i, i + 1);
+                        err = 6;
+                        goto out_dump;
+                } else if (cmp == 0 && !is_hash_key(c, key1)) {
+                        /* These can only be keys with colliding hash */
+                        dbg_err("keys %d and %d are not hashed but equivalent",
+                                i, i + 1);
+                        err = 7;
+                        goto out_dump;
+                }
+        }
+
+        kfree(idx);
+        return 0;
+
+out_dump:
+        ubifs_err("bad indexing node at LEB %d:%d, error %d", lnum, offs, err);
+        dbg_dump_node(c, idx);
+        kfree(idx);
+        return -EINVAL;
+}
+
+/**
+ * ubifs_load_znode - load znode to TNC cache.
+ * @c: UBIFS file-system description object
+ * @zbr: znode branch
+ * @parent: znode's parent
+ * @iip: index in parent
+ *
+ * This function loads znode pointed to by @zbr into the TNC cache and
+ * returns pointer to it in case of success and a negative error code in case
+ * of failure.
+ */
+struct ubifs_znode *ubifs_load_znode(struct ubifs_info *c,
+                                     struct ubifs_zbranch *zbr,
+                                     struct ubifs_znode *parent, int iip)
+{
+        int err;
+        struct ubifs_znode *znode;
+
+        ubifs_assert(!zbr->znode);
+        /*
+         * A slab cache is not presently used for znodes because the znode size
+         * depends on the fanout which is stored in the superblock.
+         */
+        znode = kzalloc(c->max_znode_sz, GFP_NOFS);
+        if (!znode)
+                return ERR_PTR(-ENOMEM);
+
+        err = read_znode(c, zbr->lnum, zbr->offs, zbr->len, znode);
+        if (err)
+                goto out;
+
+        atomic_long_inc(&c->clean_zn_cnt);
+
+        /*
+         * Increment the global clean znode counter as well. It is OK that
+         * global and per-FS clean znode counters may be inconsistent for some
+         * short time (because we might be preempted at this point), the global
+         * one is only used in shrinker.
+         */
+        atomic_long_inc(&ubifs_clean_zn_cnt);
+
+        zbr->znode = znode;
+        znode->parent = parent;
+        znode->time = get_seconds();
+        znode->iip = iip;
+
+        return znode;
+
+out:
+        kfree(znode);
+        return ERR_PTR(err);
+}
+
+/**
+ * ubifs_tnc_read_node - read a leaf node from the flash media.
+ * @c: UBIFS file-system description object
+ * @zbr: key and position of the node
+ * @node: node is returned here
+ *
+ * This function reads a node defined by @zbr from the flash media. Returns
+ * zero in case of success or a negative negative error code in case of
+ * failure.
+ */
+int ubifs_tnc_read_node(struct ubifs_info *c, struct ubifs_zbranch *zbr,
+                        void *node)
+{
+        union ubifs_key key1, *key = &zbr->key;
+        int err, type = key_type(c, key);
+        struct ubifs_wbuf *wbuf;
+
+        /*
+         * 'zbr' has to point to on-flash node. The node may sit in a bud and
+         * may even be in a write buffer, so we have to take care about this.
+         */
+        wbuf = ubifs_get_wbuf(c, zbr->lnum);
+        if (wbuf)
+                err = ubifs_read_node_wbuf(wbuf, node, type, zbr->len,
+                                           zbr->lnum, zbr->offs);
+        else
+                err = ubifs_read_node(c, node, type, zbr->len, zbr->lnum,
+                                      zbr->offs);
+
+        if (err) {
+                dbg_tnc("key %s", DBGKEY(key));
+                return err;
+        }
+
+        /* Make sure the key of the read node is correct */
+        key_read(c, key, &key1);
+        if (memcmp(node + UBIFS_KEY_OFFSET, &key1, c->key_len)) {
+                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(key), DBGKEY1(&key1));
+                dbg_dump_node(c, node);
+                return -EINVAL;
+        }
+
+        return 0;
+}