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Message-Id: <1206629746-4298-13-git-send-email-Artem.Bityutskiy@nokia.com>
Date: Thu, 27 Mar 2008 16:55:32 +0200
From: Artem Bityutskiy <Artem.Bityutskiy@...ia.com>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Adrian Hunter <ext-adrian.hunter@...ia.com>,
Artem Bityutskiy <Artem.Bityutskiy@...ia.com>
Subject: [RFC PATCH 12/26] UBIFS: add TNC implementation
TNC - tree node cache - the central UBIFS entity. It is basically
in-RAM cache of the on-flash indexing B-tree. But TNC also indexes
the journal, so that they are not always equivalent.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@...ia.com>
Signed-off-by: Adrian Hunter <ext-adrian.hunter@...ia.com>
---
fs/ubifs/tnc.c | 3483 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 3483 insertions(+), 0 deletions(-)
diff --git a/fs/ubifs/tnc.c b/fs/ubifs/tnc.c
new file mode 100644
index 0000000..27e2b60
--- /dev/null
+++ b/fs/ubifs/tnc.c
@@ -0,0 +1,3483 @@
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * Authors: Adrian Hunter
+ * Artem Bityutskiy (Битюцкий Артём)
+ */
+
+/*
+ * This file implements TNC (Tree Node Cache) which caches indexing nodes of
+ * the UBIFS B-tree.
+ *
+ * At the moment the locking rules of the TNC tree are quite simple and
+ * straightforward. We just have a mutex and lock it when we traverse the
+ * tree. If a znode is not in memory, we read it from flash while still having
+ * the mutex locked.
+ */
+
+#include <linux/crc32.h>
+#include "ubifs.h"
+
+/**
+ * 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.
+ */
+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;
+
+ ubifs_assert(lnum >= c->main_first && lnum < c->leb_cnt);
+ ubifs_assert(offs >= 0 && offs < c->leb_size);
+
+ old_idx = kmalloc(sizeof(struct ubifs_old_idx), GFP_NOFS);
+ if (!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;
+}
+
+/**
+ * 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.
+ */
+static int 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;
+}
+
+/**
+ * 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_KERNEL);
+ if (!idx)
+ return -ENOMEM;
+
+ err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs);
+ if (err < 0)
+ goto out;
+
+ 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);
+ 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 (unlikely(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);
+ 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_key(c, &zbr->key, "bad key type at slot %d: ", i);
+ goto out_dump;
+ }
+
+ if (znode->level)
+ continue;
+
+ type = key_type(c, &zbr->key);
+ if (c->ranges[type].max_len == 0) {
+ if (unlikely(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);
+ goto out_dump;
+ }
+ } else if (unlikely(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);
+ 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);
+ 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);
+ goto out_dump;
+ }
+ }
+
+ kfree(idx);
+ return 0;
+
+out:
+ kfree(idx);
+ return err;
+
+out_dump:
+ ubifs_err("bad indexing node at LEB %d:%d", lnum, offs);
+ dbg_dump_node(c, idx);
+ kfree(idx);
+ return -EINVAL;
+}
+
+/**
+ * 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.
+ */
+static struct ubifs_znode *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);
+}
+
+/**
+ * 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 = kzalloc(c->max_znode_sz, GFP_NOFS);
+ if (!zn)
+ return ERR_PTR(-ENOMEM);
+
+ memcpy(zn, znode, c->max_znode_sz);
+
+ ubifs_assert(!test_bit(OBSOLETE_ZNODE, &znode->flags));
+ set_bit(OBSOLETE_ZNODE, &znode->flags);
+
+ if (znode->level != 0) {
+ int i;
+ const int n = zn->child_cnt;
+
+ /* The children now have new parent */
+ for (i = 0; i < n; i++) {
+ struct ubifs_zbranch *zbr = &zn->zbranch[i];
+
+ if (zbr->znode)
+ zbr->znode->parent = zn;
+ }
+ }
+
+ zn->cnext = NULL;
+ set_bit(DIRTY_ZNODE, &zn->flags);
+ clear_bit(COW_ZNODE, &zn->flags);
+ atomic_long_inc(&c->dirty_zn_cnt);
+
+ return zn;
+}
+
+/**
+ * add_idx_dirt - add dirt due to a dirty znode.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number of index node
+ * @dirt: size of index node
+ *
+ * This function updates lprops dirty space and the new size of the index.
+ */
+static int add_idx_dirt(struct ubifs_info *c, int lnum, int dirt)
+{
+ c->calc_idx_sz -= ALIGN(dirt, 8);
+ return ubifs_add_dirt(c, lnum, dirt);
+}
+
+/**
+ * dirty_cow_znode - ensure a znode is not being committed.
+ * @c: UBIFS file-system description object
+ * @zbr: branch of znode to check
+ *
+ * Returns dirtied znode on success or negative error code on failure.
+ */
+static struct ubifs_znode *dirty_cow_znode(struct ubifs_info *c,
+ struct ubifs_zbranch *zbr)
+{
+ struct ubifs_znode *znode = zbr->znode;
+ struct ubifs_znode *zn;
+ int err;
+
+ if (!test_bit(COW_ZNODE, &znode->flags)) {
+ /* znode is not being committed */
+ if (!test_and_set_bit(DIRTY_ZNODE, &znode->flags)) {
+ atomic_long_inc(&c->dirty_zn_cnt);
+ atomic_long_dec(&c->clean_zn_cnt);
+ atomic_long_dec(&ubifs_clean_zn_cnt);
+ err = add_idx_dirt(c, zbr->lnum, zbr->len);
+ if (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 (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 (err)
+ return ERR_PTR(err);
+
+ return zn;
+}
+
+/**
+ * lookup_level0 - search for zero-level znode
+ * @c: UBIFS file-system description object
+ * @key: key to lookup
+ * @zn: znode is returned here
+ * @n: znode branch slot number is returned here
+ *
+ * This function looks up the TNC tree and search for zero-level znode which
+ * refers key @key. The found zero-level znode is returned in @zn. There are 3
+ * cases:
+ * o exact match, i.e. the found zero-level znode contains key @key, then %1
+ * is returned and slot number of the matched branch is stored in @n;
+ * o not exact match, which means that zero-level znode does not contain @key
+ * then %0 is returned and slot number of the closed branch is stored in
+ * @n;
+ * o @key is so small that it is even less then 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.
+ */
+static int lookup_level0(struct ubifs_info *c, const union ubifs_key *key,
+ struct ubifs_znode **zn, int *n)
+{
+ int exact;
+ struct ubifs_znode *znode;
+ unsigned long time = get_seconds();
+
+ dbg_tnc_key(c, key, "search key");
+
+ znode = c->zroot.znode;
+ if (unlikely(!znode)) {
+ znode = load_znode(c, &c->zroot, NULL, 0);
+ if (IS_ERR(znode))
+ return PTR_ERR(znode);
+ }
+
+ znode->time = time;
+
+ while (1) {
+ struct ubifs_zbranch *zbr;
+
+ /*
+ * The below is a debugging hack to make UBIFS eat RAM and
+ * cause fake memory pressure. It is compiled out if it is not
+ * enabled in kernel configuration.
+ */
+ dbg_eat_memory();
+
+ exact = search_zbranch(c, znode, key, n);
+
+ if (znode->level == 0)
+ break;
+
+ if (*n < 0)
+ *n = 0;
+ zbr = &znode->zbranch[*n];
+
+ dbg_tnc_key(c, &zbr->key, "at lvl %d, next zbr %d, key",
+ znode->level, *n);
+
+ if (zbr->znode) {
+ znode->time = time;
+ znode = zbr->znode;
+ continue;
+ }
+
+ /* znode is not in TNC cache, load it from the media */
+ znode = load_znode(c, zbr, znode, *n);
+ if (IS_ERR(znode))
+ return PTR_ERR(znode);
+ }
+
+ *zn = znode;
+ ubifs_assert(exact >= 0 && exact < c->fanout);
+ return exact;
+}
+
+/**
+ * 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 then the lowest key of the
+ * leftmost zero-level node, then %0 is returned and %0 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 exact;
+ struct ubifs_znode *znode;
+ unsigned long time = get_seconds();
+
+ dbg_tnc_key(c, key, "search and dirty key");
+
+ znode = c->zroot.znode;
+ if (unlikely(!znode)) {
+ znode = 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;
+
+ /*
+ * The below is a debugging hack to make UBIFS eat RAM and
+ * cause fake memory pressure. It is compiled out if it is not
+ * enabled in kernel configuration.
+ */
+ dbg_eat_memory();
+
+ exact = search_zbranch(c, znode, key, n);
+
+ if (znode->level == 0)
+ break;
+
+ if (*n < 0)
+ *n = 0;
+ zbr = &znode->zbranch[*n];
+
+ dbg_tnc_key(c, &zbr->key, "at lvl %d, next zbr %d, key",
+ znode->level, *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 = 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;
+ ubifs_assert(exact >= 0 && exact < c->fanout);
+ return exact;
+}
+
+/**
+ * lnc_lookup - lookup the leaf-node-cache.
+ * @c: UBIFS file-system description object
+ * @zbr: zbranch of leaf node
+ * @node: leaf node
+ *
+ * Leaf nodes are non-index nodes like dent (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.
+ *
+ * This function returns %1 if the leaf node is in the cache, %0 if it is not,
+ * and a negative error code otherwise.
+ */
+static int lnc_lookup(struct ubifs_info *c, struct ubifs_zbranch *zbr,
+ void *node)
+{
+ if (zbr->leaf == NULL)
+ return 0;
+ ubifs_assert(zbr->len != 0);
+ memcpy(node, zbr->leaf, zbr->len);
+ return 1;
+}
+
+/**
+ * ubifs_validate_entry - validate directory or extended attribute entry node.
+ * @c: UBIFS file-system description object
+ * @dent: the node to validate
+ *
+ * This function validates directory or extended attribute entry node @dent.
+ * Returns zero if the node is all right and a %-EINVAL if not.
+ */
+int ubifs_validate_entry(struct ubifs_info *c,
+ const struct ubifs_dent_node *dent)
+{
+ int key_type, nlen = le16_to_cpu(dent->nlen);
+
+ if (le32_to_cpu(dent->ch.len) != nlen + UBIFS_DENT_NODE_SZ + 1 ||
+ dent->type >= UBIFS_ITYPES_CNT ||
+ nlen > UBIFS_MAX_NLEN || dent->name[nlen] != 0 ||
+ strnlen(dent->name, nlen) != nlen ||
+ le64_to_cpu(dent->inum) > MAX_INUM) {
+ const char *node_type;
+
+ if (key_type_flash(c, dent->key) == UBIFS_DENT_KEY)
+ node_type = "directory entry";
+ else
+ node_type = "extended attribute entry";
+
+ ubifs_err("bad %s node", node_type);
+ return -EINVAL;
+ }
+
+ key_type = key_type_flash(c, dent->key);
+ if (key_type_flash(c, dent->key) != UBIFS_DENT_KEY &&
+ key_type_flash(c, dent->key) != UBIFS_XENT_KEY) {
+ ubifs_err("bad key type %d", key_type);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/**
+ * 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
+ *
+ * This function returns %0 to indicate success and a negative error code
+ * otherwise.
+ */
+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 == NULL);
+ ubifs_assert(zbr->len != 0);
+
+ /* Add all dents, but nothing else */
+ if (key_type(c, &zbr->key) != UBIFS_DENT_KEY)
+ return 0;
+
+ err = ubifs_validate_entry(c, dent);
+ if (err) {
+ dbg_dump_node(c, dent);
+ return err;
+ }
+
+ lnc_node = kmalloc(zbr->len, GFP_NOFS);
+ if (!lnc_node)
+ return 0; /* We don't have to have the cache, so no error */
+
+ memcpy(lnc_node, node, zbr->len);
+ zbr->leaf = lnc_node;
+ return 0;
+}
+
+/**
+ * lnc_free - remove a leaf node from the leaf-node-cache.
+ * @zbr: zbranch of leaf node
+ * @node: leaf node
+ *
+ * This function returns %0 to indicate success and a negative error code
+ * otherwise.
+ */
+static void lnc_free(struct ubifs_zbranch *zbr)
+{
+ if (zbr->leaf == NULL)
+ return;
+ kfree(zbr->leaf);
+ zbr->leaf = NULL;
+}
+
+/**
+ * tnc_read_node - read a leaf node.
+ * @c: UBIFS file-system description object
+ * @zbr: key and position of node
+ * @node: node returned
+ *
+ * This function reads a node or returns a negative error code.
+ */
+static int 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);
+ const struct ubifs_bud *bud;
+
+ dbg_tnc_key(c, key, "LEB %d:%d, len %d, key",
+ zbr->lnum, zbr->offs, zbr->len);
+
+ if (lnc_lookup(c, zbr, node))
+ return 0; /* Read from the leaf-node-cache */
+ /*
+ * '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.
+ */
+ if (c->jheads)
+ bud = ubifs_search_bud(c, zbr->lnum);
+ else
+ bud = NULL;
+ if (bud)
+ /* The bud can't go because we are under @c->commit_sem */
+ err = ubifs_read_node_wbuf(&c->jheads[bud->jhead].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(c, key, "key");
+ return err;
+ }
+
+ /* Make sure the key of the read node is correct */
+ key_read(c, key, &key1);
+ if (memcmp(node + UBIFS_CH_SZ, &key1, c->key_len)) {
+ ubifs_err("bad key in node at LEB %d:%d",
+ zbr->lnum, zbr->offs);
+ dbg_tnc_key(c, key, "looked for key");
+ dbg_tnc_key(c, &key1, "found node's key");
+ dbg_dump_node(c, node);
+ return err;
+ }
+
+ /* Consider adding the node to the leaf node cache */
+ err = lnc_add(c, zbr, node);
+ return err;
+}
+
+/**
+ * ubifs_try_read_node - read a node if it is a node.
+ * @c: UBIFS file-system description object
+ * @buf: buffer to read to
+ * @type: node type
+ * @len: node length (not aligned)
+ * @lnum: LEB number of node to read
+ * @offs: offset of node to read
+ *
+ * This function tries to read a node of known type and length, checks it and
+ * stores it in @buf. This function returns %1 if a node is present and %0 if
+ * a node is not present. A negative error code is returned for I/O errors.
+ * This function performs that same function as ubifs_read_node except that
+ * it does not require that there is actually a node present and instead
+ * the return code indicates if a node was read.
+ */
+static int try_read_node(const struct ubifs_info *c, void *buf, int type,
+ int len, int lnum, int offs)
+{
+ int err, node_len;
+ struct ubifs_ch *ch = buf;
+ uint32_t crc, node_crc;
+
+ dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
+ ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
+ ubifs_assert(len >= UBIFS_CH_SZ && offs + len <= c->leb_size);
+ ubifs_assert(!(offs & 7) && offs < c->leb_size);
+ ubifs_assert(type >= 0 && type < UBIFS_NODE_TYPES_CNT);
+
+ err = ubi_read(c->ubi, lnum, buf, offs, len);
+ if (err) {
+ ubifs_err("cannot read node type %d from LEB %d:%d, error %d",
+ type, lnum, offs, err);
+ return err;
+ }
+
+ if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC)
+ return 0;
+
+ if (ch->node_type != type)
+ return 0;
+
+ node_len = le32_to_cpu(ch->len);
+ if (node_len != len)
+ return 0;
+
+ crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
+ node_crc = le32_to_cpu(ch->crc);
+ if (crc != node_crc)
+ return 0;
+
+ return 1;
+}
+
+/**
+ * fallible_read_node - try to read a leaf node.
+ * @c: UBIFS file-system description object
+ * @key: key of node to read
+ * @zbr: position of node
+ * @node: node returned
+ *
+ * This function tries to read a node and returns %1 if the node is read, %0
+ * if the node is not present, and a negative error code in the case of error.
+ */
+static int fallible_read_node(struct ubifs_info *c, const union ubifs_key *key,
+ struct ubifs_zbranch *zbr, void *node)
+{
+ int ret;
+
+ dbg_tnc_key(c, key, "key");
+
+ if (lnc_lookup(c, zbr, node))
+ return 0; /* Read from the leaf-node-cache */
+
+ ret = try_read_node(c, node, key_type(c, key), zbr->len, zbr->lnum,
+ zbr->offs);
+ if (ret == 1) {
+ union ubifs_key node_key;
+
+ /* All nodes have key in the same place */
+ key_read(c, &((struct ubifs_dent_node *)node)->key, &node_key);
+ if (keys_cmp(c, key, &node_key) == 0) {
+ /* Consider adding the node to the leaf node cache */
+ int err = lnc_add(c, zbr, node);
+
+ if (err)
+ return err;
+ } else
+ ret = 0;
+ } else if (ret == 0)
+ dbg_gc_key(c, key, "dangling branch LEB %d:%d len %d, key",
+ zbr->lnum, zbr->offs, zbr->len);
+ return ret;
+}
+
+/**
+ * matches_name - determine if a directory or extended attribute entry matches
+ * a given name.
+ * @c: UBIFS file-system description object
+ * @zt: zbranch of dent
+ * @nm: name to match
+ *
+ * This function returns %1 if the name matches, %0 if the name does not match
+ * and a negative error code otherwise.
+ */
+static int matches_name(struct ubifs_info *c, struct ubifs_zbranch *zt,
+ const struct qstr *nm)
+{
+ struct ubifs_dent_node *dent;
+ int nlen, err;
+
+ /* If possible, match against the dent in the leaf-node-cache */
+ dent = zt->leaf;
+ if (dent) {
+ nlen = le16_to_cpu(dent->nlen);
+
+ if (nlen == nm->len && !memcmp(dent->name, nm->name, nlen))
+ return 1;
+ return 0;
+ }
+
+ dent = kmalloc(zt->len, GFP_NOFS);
+ if (!dent)
+ return -ENOMEM;
+ /*
+ * In this case we end up allocating another dent object in lnc_add(),
+ * although it could have just inserted this dent.
+ */
+ err = tnc_read_node(c, zt, dent);
+ if (!err) {
+ err = ubifs_validate_entry(c, dent);
+ if (err) {
+ dbg_dump_node(c, dent);
+ goto out;
+ }
+
+ nlen = le16_to_cpu(dent->nlen);
+ if (nlen == nm->len && !memcmp(dent->name, nm->name, nlen))
+ err = 1;
+ }
+
+out:
+ 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 = 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
+ * @nn: 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 *nn)
+{
+ struct ubifs_znode *znode = *zn;
+ int n = *nn;
+
+ n += 1;
+ if (n < znode->child_cnt) {
+ *nn = n;
+ return 0;
+ }
+ while (1) {
+ struct ubifs_znode *zp;
+
+ zp = znode->parent;
+ if (!zp)
+ return -ENOENT;
+ n = znode->iip + 1;
+ znode = zp;
+ if (n < znode->child_cnt) {
+ znode = get_znode(c, znode, n);
+ 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);
+ }
+ n = 0;
+ break;
+ }
+ }
+ *zn = znode;
+ *nn = n;
+ return 0;
+}
+
+/**
+ * tnc_prev - find previous TNC entry.
+ * @c: UBIFS file-system description object
+ * @zn: znode is returned here
+ * @nn: 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 *nn)
+{
+ struct ubifs_znode *znode = *zn;
+ int n = *nn;
+
+ if (n > 0) {
+ *nn = n - 1;
+ return 0;
+ }
+ while (1) {
+ struct ubifs_znode *zp;
+
+ zp = znode->parent;
+ if (!zp)
+ return -ENOENT;
+ n = znode->iip - 1;
+ znode = zp;
+ if (n >= 0) {
+ znode = get_znode(c, znode, n);
+ if (IS_ERR(znode))
+ return PTR_ERR(znode);
+ while (znode->level != 0) {
+ n = znode->child_cnt - 1;
+ znode = get_znode(c, znode, n);
+ if (IS_ERR(znode))
+ return PTR_ERR(znode);
+ }
+ n = znode->child_cnt - 1;
+ break;
+ }
+ }
+ *zn = znode;
+ *nn = n;
+ 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
+ * @nn: znode branch slot number is passed and returned here
+ * @nm: name of the entry
+ *
+ * This function returns %1 and sets @zn and @nn if the collision is resolved.
+ * %0 is returned if @nm is not found and @zn and @nn are set to the next
+ * entry. %-ENOENT is returned if there are no following entries for the same
+ * inode. Otherwise a negative error code is returned.
+ */
+static int resolve_collision(struct ubifs_info *c, const union ubifs_key *key,
+ struct ubifs_znode **zn, int *nn,
+ const struct qstr *nm)
+{
+ struct ubifs_znode *znode;
+ union ubifs_key *okey;
+ int n, err;
+
+ dbg_tnc_key(c, key, "key");
+
+ znode = *zn;
+ n = *nn;
+ err = matches_name(c, &znode->zbranch[n], nm);
+ if (err < 0)
+ return err;
+ if (err == 1)
+ return 1;
+
+ /* Look left */
+ while (1) {
+ err = tnc_prev(c, &znode, &n);
+ if (err == -ENOENT)
+ break;
+ if (err)
+ return err;
+ if (keys_cmp(c, &znode->zbranch[n].key, key))
+ break;
+ err = matches_name(c, &znode->zbranch[n], nm);
+ if (err < 0)
+ return err;
+ if (err == 1) {
+ dbg_tnc_key(c, key, "collision resolved");
+ *zn = znode;
+ *nn = n;
+ return 1;
+ }
+ }
+
+ /* Look right */
+ znode = *zn;
+ n = *nn;
+ while (1) {
+ err = tnc_next(c, &znode, &n);
+ if (err)
+ return err;
+ okey = &znode->zbranch[n].key;
+ if (keys_cmp(c, okey, key))
+ return -ENOENT;
+ err = matches_name(c, &znode->zbranch[n], nm);
+ if (err < 0)
+ return err;
+ if (err == 1) {
+ dbg_tnc_key(c, key, "collision resolved");
+ *zn = znode;
+ *nn = n;
+ return 1;
+ }
+ }
+
+ return -EINVAL;
+}
+
+/**
+ * fallible_matches_name - determine if a dent matches a given name.
+ * @c: UBIFS file-system description object
+ * @zt: zbranch of dent
+ * @nm: name to match
+ *
+ * This function returns %1 if the name matches, %0 if the name does not match,
+ * %2 if the node was not present, and a negative error code otherwise.
+ */
+static int fallible_matches_name(struct ubifs_info *c, struct ubifs_zbranch *zt,
+ const struct qstr *nm)
+{
+ struct ubifs_dent_node *dent;
+ int nlen, err;
+
+ /* If possible, match against the dent in the leaf-node-cache */
+ dent = zt->leaf;
+ if (dent) {
+ nlen = le16_to_cpu(dent->nlen);
+
+ if (nlen == nm->len && !memcmp(dent->name, nm->name, nlen))
+ return 1;
+ return 0;
+ }
+
+ dent = kmalloc(zt->len, GFP_NOFS);
+ if (!dent)
+ return -ENOMEM;
+ /*
+ * In this case we end up allocating another dent object in lnc_add(),
+ * although it could have just inserted this dent.
+ */
+ err = fallible_read_node(c, &zt->key, zt, dent);
+ if (err < 0)
+ goto out;
+ if (err == 0) {
+ err = 2; /* The node was not present */
+ goto out;
+ }
+ if (err == 1) {
+ err = ubifs_validate_entry(c, dent);
+ if (err) {
+ dbg_dump_node(c, dent);
+ goto out;
+ }
+
+ nlen = le16_to_cpu(dent->nlen);
+ if (nlen == nm->len && !memcmp(dent->name, nm->name, nlen))
+ err = 1;
+ else
+ err = 0;
+ }
+out:
+ kfree(dent);
+ return err;
+}
+
+/**
+ * fallible_resolve_collision - resolve a collision even if nodes are missing.
+ * @c: UBIFS file-system description object
+ * @key: key of directory entry
+ * @zn: znode is returned here
+ * @nn: znode branch slot number is passed and returned here
+ * @nm: name of directory entry
+ *
+ * This function returns %1 and sets @zn and @nn if the collision is resolved.
+ * %0 is returned if @nm is not found and @zn and @nn are set to the
+ * next directory entry. %-ENOENT is returned if there are no
+ * following directory entries for the same inode. Otherwise a negative error
+ * code is returned.
+ */
+static int fallible_resolve_collision(struct ubifs_info *c,
+ const union ubifs_key *key,
+ struct ubifs_znode **zn, int *nn,
+ const struct qstr *nm)
+{
+ struct ubifs_znode *znode, *o_znode = NULL;
+ union ubifs_key *okey;
+ int n, o_n = 0, err;
+
+ dbg_tnc_key(c, key, "key");
+ znode = *zn;
+ n = *nn;
+ err = fallible_matches_name(c, &znode->zbranch[n], nm);
+ if (err < 0)
+ return err;
+ if (err == 1)
+ return 1;
+ if (err == 2) {
+ o_znode = znode;
+ o_n = n;
+ }
+
+ /* Look left */
+ while (1) {
+ err = tnc_prev(c, &znode, &n);
+ if (err == -ENOENT)
+ break;
+ if (err)
+ return err;
+ if (keys_cmp(c, &znode->zbranch[n].key, key))
+ break;
+ err = fallible_matches_name(c, &znode->zbranch[n], nm);
+ if (err < 0)
+ return err;
+ if (err == 1) {
+ dbg_tnc_key(c, key, "collision resolved");
+ *zn = znode;
+ *nn = n;
+ return 1;
+ }
+ if (err == 2) {
+ o_znode = znode;
+ o_n = n;
+ }
+ }
+ /* Look right */
+ znode = *zn;
+ n = *nn;
+ while (1) {
+ err = tnc_next(c, &znode, &n);
+ if (err == -ENOENT && o_znode) {
+ dbg_tnc_key(c, key, "collision resolved by default");
+ dbg_gc_key(c, key, "dangling match LEB %d:%d len %d ",
+ o_znode->zbranch[o_n].lnum,
+ o_znode->zbranch[o_n].offs,
+ o_znode->zbranch[o_n].len);
+ *zn = o_znode;
+ *nn = o_n;
+ return 1;
+ }
+ if (err)
+ return err;
+ okey = &znode->zbranch[n].key;
+ if (keys_cmp(c, okey, key)) {
+ if (!o_znode)
+ return -ENOENT;
+ dbg_tnc_key(c, key, "collision resolved by default");
+ dbg_gc_key(c, key, "dangling match LEB %d:%d len %d ",
+ o_znode->zbranch[o_n].lnum,
+ o_znode->zbranch[o_n].offs,
+ o_znode->zbranch[o_n].len);
+ *zn = o_znode;
+ *nn = o_n;
+ return 1;
+ }
+ err = fallible_matches_name(c, &znode->zbranch[n], nm);
+ if (err < 0)
+ return err;
+ if (err == 1) {
+ dbg_tnc_key(c, key, "collision resolved");
+ *zn = znode;
+ *nn = n;
+ return 1;
+ }
+ if (err == 2) {
+ o_znode = znode;
+ o_n = n;
+ }
+ }
+ return -EINVAL;
+}
+
+/**
+ * matches_position - determine if a zbranch matches a given position.
+ * @zt: 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 *zt, int lnum, int offs)
+{
+ if (zt->lnum == lnum && zt->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
+ * @nn: znode branch slot number is passed and returned here
+ * @lnum: LEB number of dent node to match
+ * @offs: offset of dent node to match
+ *
+ * This function returns %1 and sets @zn and @nn if the collision is resolved.
+ * %0 is returned if @lnum:@offs is not found and @zn and @nn are set to the
+ * next directory entry. %-ENOENT is returned if there are no
+ * following directory entries for the same inode. 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 *nn,
+ int lnum, int offs)
+{
+ struct ubifs_znode *znode;
+ union ubifs_key *okey;
+ int n, err;
+
+ dbg_tnc_key(c, key, "key");
+ dbg_mnt_key(c, key, "LEB %d:%d", lnum, offs);
+ znode = *zn;
+ n = *nn;
+ if (matches_position(&znode->zbranch[n], lnum, offs))
+ return 1;
+
+ /* Look left */
+ while (1) {
+ err = tnc_prev(c, &znode, &n);
+ if (err == -ENOENT)
+ break;
+ if (err)
+ return err;
+ if (keys_cmp(c, &znode->zbranch[n].key, key))
+ break;
+ if (matches_position(&znode->zbranch[n], lnum, offs)) {
+ dbg_tnc_key(c, key, "collision resolved");
+ dbg_mnt_key(c, key, "LEB %d:%d collision resolved",
+ lnum, offs);
+ *zn = znode;
+ *nn = n;
+ return 1;
+ }
+ }
+
+ /* Look right */
+ znode = *zn;
+ n = *nn;
+ while (1) {
+ err = tnc_next(c, &znode, &n);
+ if (err)
+ return err;
+ okey = &znode->zbranch[n].key;
+ if (keys_cmp(c, okey, key))
+ return 0;
+ if (matches_position(&znode->zbranch[n], lnum, offs)) {
+ dbg_tnc_key(c, key, "collision resolved");
+ dbg_mnt_key(c, key, "LEB %d:%d collision resolved",
+ lnum, offs);
+ *zn = znode;
+ *nn = n;
+ return 1;
+ }
+ }
+}
+
+/**
+ * ubifs_tnc_lookup - look up a file-system node.
+ * @c: UBIFS file-system description object
+ * @key: node key to lookup
+ * @node: the node is returned here
+ *
+ * This function look up and reads node with key @key. The caller has to make
+ * sure the @node buffer is large enough to fit the node. Returns zero in case
+ * of success, %-ENOENT if the node was not found, and a negative error code in
+ * case of failure.
+ */
+int ubifs_tnc_lookup(struct ubifs_info *c, const union ubifs_key *key,
+ void *node)
+{
+ int found, n, err;
+ struct ubifs_znode *znode;
+ struct ubifs_zbranch zbr, *zt;
+
+ mutex_lock(&c->tnc_mutex);
+ found = lookup_level0(c, key, &znode, &n);
+ if (!found) {
+ err = -ENOENT;
+ goto out;
+ } else if (found < 0) {
+ err = found;
+ goto out;
+ }
+ zt = &znode->zbranch[n];
+ if (is_hash_key(c, key)) {
+ /*
+ * In this case the leaf-node-cache gets used, so we pass the
+ * address of the zbranch and keep the mutex locked
+ */
+ err = tnc_read_node(c, zt, node);
+ goto out;
+ }
+ zbr = znode->zbranch[n];
+ mutex_unlock(&c->tnc_mutex);
+
+ err = tnc_read_node(c, &zbr, node);
+ return err;
+
+out:
+ mutex_unlock(&c->tnc_mutex);
+ return err;
+}
+
+/**
+ * ubifs_tnc_locate - look up a file-system node and return it and its location.
+ * @c: UBIFS file-system description object
+ * @key: node key to lookup
+ * @node: the node is returned here
+ * @lnum: LEB number is returned here
+ * @offs: offset is returned here
+ *
+ * This function is the same as 'ubifs_tnc_lookup()' but it returns the node
+ * location also. See 'ubifs_tnc_lookup()'.
+ */
+int ubifs_tnc_locate(struct ubifs_info *c, const union ubifs_key *key,
+ void *node, int *lnum, int *offs)
+{
+ int found, n, err;
+ struct ubifs_znode *znode;
+ struct ubifs_zbranch zbr, *zt;
+
+ mutex_lock(&c->tnc_mutex);
+ found = lookup_level0(c, key, &znode, &n);
+ if (!found) {
+ err = -ENOENT;
+ goto out;
+ } else if (found < 0) {
+ err = found;
+ goto out;
+ }
+ zt = &znode->zbranch[n];
+ if (is_hash_key(c, key)) {
+ /*
+ * In this case the leaf-node-cache gets used, so we pass the
+ * address of the zbranch and keep the mutex locked
+ */
+ *lnum = zt->lnum;
+ *offs = zt->offs;
+ err = tnc_read_node(c, zt, node);
+ goto out;
+ }
+ zbr = znode->zbranch[n];
+ mutex_unlock(&c->tnc_mutex);
+
+ *lnum = zbr.lnum;
+ *offs = zbr.offs;
+
+ err = tnc_read_node(c, &zbr, node);
+ return err;
+
+out:
+ mutex_unlock(&c->tnc_mutex);
+ return err;
+}
+
+/**
+ * do_lookup_nm- look up a "hashed" node.
+ * directory entry file-system node.
+ * @c: UBIFS file-system description object
+ * @key: node key to lookup
+ * @node: the node is returned here
+ * @nm: node name
+ *
+ * This function look up and reads a node which contains name hash in the key.
+ * Since the hash may have collisions, there may be many nodes with the same
+ * key, so we have to sequentially look to all of them until the needed one is
+ * found. This function returns zero in case of success, %-ENOENT if the node
+ * was not found, and a negative error code in case of failure.
+ */
+static int do_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
+ void *node, const struct qstr *nm)
+{
+ int found, n, err;
+ struct ubifs_znode *znode;
+ struct ubifs_zbranch zbr;
+
+ dbg_tnc_key(c, key, "key");
+ mutex_lock(&c->tnc_mutex);
+ found = lookup_level0(c, key, &znode, &n);
+ if (!found) {
+ err = -ENOENT;
+ goto out;
+ } else if (found < 0) {
+ err = found;
+ goto out;
+ }
+
+ ubifs_assert(n >= 0);
+
+ err = resolve_collision(c, key, &znode, &n, nm);
+ if (err < 0)
+ goto out;
+ if (err == 0) {
+ err = -ENOENT;
+ goto out;
+ }
+
+ zbr = znode->zbranch[n];
+ mutex_unlock(&c->tnc_mutex);
+
+ err = tnc_read_node(c, &zbr, node);
+
+ return err;
+
+out:
+ mutex_unlock(&c->tnc_mutex);
+ return err;
+}
+
+/**
+ * ubifs_tnc_lookup_nm- look up a "hashed" node.
+ * directory entry file-system 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;
+ if (!znode->parent || znode->iip)
+ break;
+ key1 = &znode->parent->zbranch[0].key;
+ }
+}
+
+/**
+ * insert_zbranch - insert a zbranch into a znode.
+ * @znode: znode into which to insert
+ * @zbr: zbranch to insert
+ * @n: slot number to insert to
+ *
+ * This is a helper function for 'tnc_insert()'. UBIFS does not allow "gaps" in
+ * znode's array of zbranches and keeps zbranches consolidated, so when a new
+ * zbranch has to be inserted to the @znode->zbranches[]' array at the @n-th
+ * slot, zbranches starting from @n have to be moved right.
+ */
+static void insert_zbranch(struct ubifs_znode *znode,
+ const struct ubifs_zbranch *zbr, int n)
+{
+ int i;
+
+ ubifs_assert(ubifs_zn_dirty(znode));
+
+ if (znode->level) {
+ for (i = znode->child_cnt; i > n; i--) {
+ znode->zbranch[i] = znode->zbranch[i - 1];
+ if (znode->zbranch[i].znode)
+ znode->zbranch[i].znode->iip = i;
+ }
+ if (zbr->znode)
+ zbr->znode->iip = n;
+ } else
+ for (i = znode->child_cnt; i > n; i--)
+ znode->zbranch[i] = znode->zbranch[i - 1];
+
+ znode->zbranch[n] = *zbr;
+ znode->child_cnt += 1;
+ /*
+ * After inserting at slot zero, the lower bound of the key range of
+ * this znode may have changed. If this znode is subsequently split
+ * then the upper bound of the key range may change, and furthermore
+ * it could change to be lower than the original lower bound. If that
+ * happens, then it will no longer be possible to find this znode in the
+ * TNC using the key from the index node on flash. That is bad because
+ * if it is not found, we will assume it is obsolete and may overwrite
+ * it. Then if there is an unclean unmount, we will start using the
+ * old index which will be broken.
+ *
+ * So we first mark znodes that have insertions at slot zero, and then
+ * if they are split we add their lnum/offs to the old_idx tree.
+ */
+ if (n == 0)
+ znode->alt = 1;
+}
+
+/**
+ * tnc_insert - insert a node into TNC.
+ * @c: UBIFS file-system description object
+ * @znode: znode to insert into
+ * @zbr: branch to insert
+ * @n: slot number to insert new zbranch to
+ *
+ * This function inserts a new node described by @zbr into znode @znode. If
+ * znode does not have a free slot for new zbranch, it is split. Parent znodes
+ * are splat as well if needed. Returns zero in case of success or a negative
+ * error code in case of failure.
+ */
+static int tnc_insert(struct ubifs_info *c, struct ubifs_znode *znode,
+ struct ubifs_zbranch *zbr, int n)
+{
+ struct ubifs_znode *zn, *zi, *zp;
+ int i, keep, move, appending = 0;
+ union ubifs_key *key = &zbr->key;
+
+ ubifs_assert(n >= 0 && n <= c->fanout);
+
+ /* Implement naive insert for now */
+again:
+ zp = znode->parent;
+ if (znode->child_cnt < c->fanout) {
+ ubifs_assert(n != c->fanout);
+ dbg_tnc_key(c, key, "inserted at %d level %d, key ", n,
+ znode->level);
+
+ 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_key(c, key, "splitting level %d, key ", znode->level);
+
+ if (znode->alt)
+ /*
+ * We can no longer be sure of finding this znode by key, so we
+ * record it in the old_idx tree.
+ */
+ ins_clr_old_idx_znode(c, znode);
+
+ zn = kzalloc(c->max_znode_sz, GFP_NOFS);
+ if (!zn)
+ return -ENOMEM;
+ zn->parent = zp;
+ zn->level = znode->level;
+
+ /* Decide where to split */
+ if (znode->level == 0 && n == c->fanout &&
+ key_type(c, key) == UBIFS_DATA_KEY) {
+ union ubifs_key *key1;
+
+ /*
+ * If this is an inode which is being appended - do not split
+ * it because no other zbranches can be inserted between
+ * zbranches of consecutive data nodes anyway.
+ */
+ key1 = &znode->zbranch[n - 1].key;
+ if (key_ino(c, key1) == key_ino(c, key) &&
+ key_type(c, key1) == UBIFS_DATA_KEY &&
+ key_block(c, key1) == key_block(c, key) - 1)
+ appending = 1;
+ }
+
+ if (appending) {
+ keep = c->fanout;
+ move = 0;
+ } else {
+ keep = (c->fanout + 1) / 2;
+ move = c->fanout - keep;
+ }
+
+ /*
+ * Although we don't at present, we could look at the neighbors and see
+ * if we can move some zbranches there.
+ */
+
+ if (n < keep) {
+ /* Insert into existing znode */
+ zi = znode;
+ move += 1;
+ keep -= 1;
+ } else {
+ /* Insert into new znode */
+ zi = zn;
+ n -= keep;
+ /* Re-parent */
+ if (zn->level != 0)
+ zbr->znode->parent = zn;
+ }
+
+ set_bit(DIRTY_ZNODE, &zn->flags);
+ atomic_long_inc(&c->dirty_zn_cnt);
+
+ zn->child_cnt = move;
+ znode->child_cnt = keep;
+
+ dbg_tnc("moving %d, keeping %d", move, keep);
+
+ /* Move zbranch */
+ for (i = 0; i < move; i++) {
+ zn->zbranch[i] = znode->zbranch[keep + i];
+ /* Re-parent */
+ if (zn->level != 0)
+ if (zn->zbranch[i].znode) {
+ zn->zbranch[i].znode->parent = zn;
+ zn->zbranch[i].znode->iip = i;
+ }
+ }
+
+ /* Insert new key and branch */
+ dbg_tnc_key(c, key, "inserting at %d level %d, key ", n,
+ zn->level);
+
+ insert_zbranch(zi, zbr, n);
+
+ /* Insert new znode (produced by spitting) into the parent */
+ if (zp) {
+ i = n;
+ /* Locate insertion point */
+ n = znode->iip + 1;
+ if (appending && n != c->fanout)
+ appending = 0;
+
+ if (i == 0 && zi == znode && znode->iip == 0)
+ correct_parent_keys(c, znode);
+
+ /* Tail recursion */
+ zbr->key = zn->zbranch[0].key;
+ zbr->znode = zn;
+ zbr->lnum = 0;
+ zbr->offs = 0;
+ zbr->len = 0;
+ znode = zp;
+
+ goto again;
+ }
+
+ /* We have to split root znode */
+ dbg_tnc("creating new zroot at level %d", znode->level + 1);
+
+ zi = kzalloc(c->max_znode_sz, GFP_NOFS);
+ if (!zi)
+ return -ENOMEM;
+
+ zi->child_cnt = 2;
+ zi->level = znode->level + 1;
+
+ set_bit(DIRTY_ZNODE, &zi->flags);
+ atomic_long_inc(&c->dirty_zn_cnt);
+
+ zi->zbranch[0].key = znode->zbranch[0].key;
+ zi->zbranch[0].znode = znode;
+ zi->zbranch[0].lnum = c->zroot.lnum;
+ zi->zbranch[0].offs = c->zroot.offs;
+ zi->zbranch[0].len = c->zroot.len;
+ zi->zbranch[1].key = zn->zbranch[0].key;
+ zi->zbranch[1].znode = zn;
+
+ c->zroot.lnum = 0;
+ c->zroot.offs = 0;
+ c->zroot.len = 0;
+ c->zroot.znode = zi;
+
+ zn->parent = zi;
+ zn->iip = 1;
+ znode->parent = zi;
+ znode->iip = 0;
+
+ return 0;
+}
+
+/**
+ * ubifs_tnc_add - add a node to TNC.
+ * @c: UBIFS file-system description object
+ * @key: key to add
+ * @lnum: LEB number of node
+ * @offs: node offset
+ * @len: node length
+ *
+ * This function adds a node with key @key to TNC. The node may be new or it may
+ * obsolete some existing one. Returns %0 on success or negative error code on
+ * failure.
+ */
+int ubifs_tnc_add(struct ubifs_info *c, const union ubifs_key *key, int lnum,
+ int offs, int len)
+{
+ int found, n, err = 0;
+ struct ubifs_znode *znode;
+
+ mutex_lock(&c->tnc_mutex);
+ 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;
+ zbr.key = *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;
+}
+
+/**
+ * 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 = NULL, h, p = 0;
+
+ ubifs_assert(c->zroot.znode != NULL);
+ ubifs_assert(znode != NULL);
+ h = c->zroot.znode->level;
+ if (h) {
+ path = kmalloc(sizeof(int) * h, GFP_NOFS);
+ if (!path)
+ return ERR_PTR(-ENOMEM);
+ /* Go up until parent is dirty */
+ while (1) {
+ int n;
+
+ zp = znode->parent;
+ if (!zp)
+ break;
+ n = znode->iip;
+ ubifs_assert(p < h);
+ 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;
+ }
+ kfree(path);
+ return znode;
+}
+
+/**
+ * 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);
+ found = lookup_level0_dirty(c, key, &znode, &n);
+ if (found < 0) {
+ err = found;
+ goto out;
+ } else 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;
+ 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);
+ if (found == -ENOENT)
+ found = 0;
+ if (found < 0) {
+ err = found;
+ goto out;
+ } else 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;
+ }
+ }
+ zbr = &znode->zbranch[n];
+ lnc_free(zbr);
+ err = ubifs_add_dirt(c, zbr->lnum,
+ zbr->len);
+ if (err)
+ goto out;
+ zbr->lnum = lnum;
+ zbr->offs = offs;
+ zbr->len = len;
+ }
+ }
+ }
+
+ if (found == 0) {
+ err = ubifs_add_dirt(c, lnum, len);
+ if (err)
+ goto out;
+ }
+
+ err = dbg_check_tnc(c, 0);
+
+out:
+ 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);
+ found = lookup_level0_dirty(c, key, &znode, &n);
+ if (found < 0) {
+ err = found;
+ goto out;
+ }
+ if (found == 1) {
+ if (c->replaying)
+ found = fallible_resolve_collision(c, key, &znode, &n,
+ nm);
+ else
+ found = resolve_collision(c, key, &znode, &n, nm);
+ if (found < 0 && found != -ENOENT) {
+ err = found;
+ goto out;
+ }
+ /* 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;
+ }
+ }
+ if (found == 0)
+ n -= 1;
+ else if (found == -ENOENT)
+ found = 0;
+ 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;
+ goto out;
+ }
+ }
+ if (!found) {
+ struct ubifs_zbranch zbr;
+
+ zbr.znode = NULL;
+ zbr.lnum = lnum;
+ zbr.offs = offs;
+ zbr.len = len;
+ zbr.key = *key;
+ err = tnc_insert(c, znode, &zbr, n + 1);
+ }
+
+out:
+ 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_key(c, &znode->zbranch[n].key, "deleting");
+
+ zbr = &znode->zbranch[n];
+ lnc_free(zbr);
+
+ err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
+ if (err) {
+ dbg_dump_znode(c, znode);
+ return err;
+ }
+
+ /* We do not "gap" zbranch slots */
+ for (i = n; i < znode->child_cnt - 1; i++)
+ znode->zbranch[i] = znode->zbranch[i + 1];
+ znode->child_cnt -= 1;
+
+ if (znode->child_cnt > 0)
+ return 0;
+
+ /*
+ * This was the last zbranch, we have to delete this znode from the
+ * parent.
+ */
+
+ do {
+ ubifs_assert(!test_bit(OBSOLETE_ZNODE, &znode->flags));
+ ubifs_assert(ubifs_zn_dirty(znode));
+
+ zp = znode->parent;
+ n = znode->iip;
+
+ atomic_long_dec(&c->dirty_zn_cnt);
+
+ err = insert_old_idx_znode(c, znode);
+ if (err)
+ return err;
+
+ if (znode->cnext) {
+ set_bit(OBSOLETE_ZNODE, &znode->flags);
+ atomic_long_inc(&c->clean_zn_cnt);
+ atomic_long_inc(&ubifs_clean_zn_cnt);
+ } else
+ kfree(znode);
+ znode = zp;
+ } while (znode->child_cnt == 1); /* while removing last child */
+
+ /* Remove from znode, entry n - 1 */
+ znode->child_cnt -= 1;
+ ubifs_assert(znode->level != 0);
+ for (i = n; i < znode->child_cnt; i++) {
+ znode->zbranch[i] = znode->zbranch[i + 1];
+ if (znode->zbranch[i].znode)
+ znode->zbranch[i].znode->iip = i;
+ }
+
+ /*
+ * If this is the root and it has only 1 child then
+ * collapse the tree.
+ */
+ if (znode->parent == NULL) {
+ while (znode->child_cnt == 1 && znode->level != 0) {
+ zp = znode;
+ zbr = &znode->zbranch[0];
+ znode = get_znode(c, znode, 0);
+ if (IS_ERR(znode))
+ return PTR_ERR(znode);
+ znode = dirty_cow_znode(c, zbr);
+ if (IS_ERR(znode))
+ return PTR_ERR(znode);
+ znode->parent = NULL;
+ znode->iip = 0;
+ if (c->zroot.len) {
+ err = insert_old_idx(c, c->zroot.lnum,
+ c->zroot.offs);
+ if (err)
+ return err;
+ }
+ c->zroot.lnum = zbr->lnum;
+ c->zroot.offs = zbr->offs;
+ c->zroot.len = zbr->len;
+ c->zroot.znode = znode;
+ ubifs_assert(!test_bit(OBSOLETE_ZNODE,
+ &zp->flags));
+ ubifs_assert(test_bit(DIRTY_ZNODE, &zp->flags));
+ atomic_long_dec(&c->dirty_zn_cnt);
+
+ if (zp->cnext) {
+ set_bit(OBSOLETE_ZNODE, &zp->flags);
+ atomic_long_inc(&c->clean_zn_cnt);
+ atomic_long_inc(&ubifs_clean_zn_cnt);
+ } else
+ kfree(zp);
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * ubifs_tnc_remove - remove an index entry of a node.
+ * @c: UBIFS file-system description object
+ * @key: key of node
+ *
+ * Returns %0 on success or negative error code on failure.
+ */
+int ubifs_tnc_remove(struct ubifs_info *c, const union ubifs_key *key)
+{
+ int found, n, err = 0;
+ struct ubifs_znode *znode;
+
+ mutex_lock(&c->tnc_mutex);
+ found = lookup_level0_dirty(c, key, &znode, &n);
+ if (found == 1)
+ err = tnc_delete(c, znode, n);
+ else if (found < 0)
+ err = found;
+ if (!err)
+ err = dbg_check_tnc(c, 0);
+ 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 found, n, err = 0;
+ struct ubifs_znode *znode;
+
+ mutex_lock(&c->tnc_mutex);
+ found = lookup_level0_dirty(c, key, &znode, &n);
+ if (found < 0) {
+ err = found;
+ goto out;
+ }
+ if (found) {
+ if (c->replaying)
+ found = fallible_resolve_collision(c, key, &znode, &n,
+ nm);
+ else
+ found = resolve_collision(c, key, &znode, &n, nm);
+ if (found == -ENOENT)
+ found = 0;
+ if (found < 0) {
+ err = found;
+ goto out;
+ }
+ 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;
+ }
+ }
+ err = tnc_delete(c, znode, n);
+ }
+ }
+out:
+ 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 found, 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 */
+ found = lookup_level0(c, from_key, &znode, &n);
+ if (found < 0) {
+ err = found;
+ goto out;
+ }
+ if (found)
+ key = from_key;
+ else {
+ err = tnc_next(c, &znode, &n);
+ if (err == -ENOENT) {
+ err = 0;
+ goto out;
+ }
+ if (err < 0)
+ goto out;
+ key = &znode->zbranch[n].key;
+ if (!key_in_range(c, key, from_key, to_key)) {
+ err = 0;
+ goto out;
+ }
+ }
+ /* 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;
+ }
+ }
+ /* 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;
+ }
+ dbg_tnc_key(c, key, "removing");
+ }
+ 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;
+ }
+out:
+ if (!err)
+ err = dbg_check_tnc(c, 0);
+ mutex_unlock(&c->tnc_mutex);
+ return err;
+}
+
+/**
+ * ubifs_tnc_remove_ino - remove an inode from TNC.
+ * @c: UBIFS file-system description object
+ * @inum: inode number to remove
+ *
+ * This function remove inode @inum and all the extended attributes associated
+ * with the anode from TNC and returns zero in case of success or a negative
+ * error code in case of failure.
+ */
+int ubifs_tnc_remove_ino(struct ubifs_info *c, ino_t inum)
+{
+ union ubifs_key key1, key2;
+ struct ubifs_dent_node *xent, *pxent = NULL;
+ struct qstr nm = { .name = NULL };
+
+ dbg_tnc("ino %lu", inum);
+
+ /*
+ * Walk all extended attribute entries and remove them together with
+ * corresponding extended attribute inodes.
+ */
+ lowest_xent_key(c, &key1, inum);
+ while (1) {
+ ino_t xattr_inum;
+ int err;
+
+ xent = ubifs_tnc_next_ent(c, &key1, &nm);
+ if (IS_ERR(xent)) {
+ err = PTR_ERR(xent);
+ if (err == -ENOENT)
+ break;
+ return err;
+ }
+
+ xattr_inum = le64_to_cpu(xent->inum);
+ dbg_tnc("xent '%s', ino %lu", xent->name, xattr_inum);
+
+ nm.name = xent->name;
+ nm.len = le16_to_cpu(xent->nlen);
+ err = ubifs_tnc_remove_nm(c, &key1, &nm);
+ if (err) {
+ kfree(xent);
+ return err;
+ }
+
+ lowest_ino_key(c, &key1, xattr_inum);
+ highest_ino_key(c, &key2, xattr_inum);
+ err = ubifs_tnc_remove_range(c, &key1, &key2);
+ if (err) {
+ kfree(xent);
+ return err;
+ }
+
+ kfree(pxent);
+ pxent = xent;
+ key_read(c, &xent->key, &key1);
+ }
+
+ kfree(pxent);
+ lowest_ino_key(c, &key1, inum);
+ highest_ino_key(c, &key2, inum);
+
+ return ubifs_tnc_remove_range(c, &key1, &key2);
+}
+
+/**
+ * ubifs_tnc_next_ent - walk directory or extended attribute entries.
+ * @c: UBIFS file-system description object
+ * @key: key of last entry
+ * @nm: name of last entry found or %NULL
+ *
+ * This function finds and reads the next directory or extended attribute entry
+ * after the given key (@key) if there is one. @name is used to resolve
+ * collisions. 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 is found, or a negative
+ * error code 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 found, n, err, type = key_type(c, key), dlen = 0;
+ struct ubifs_znode *znode;
+ struct ubifs_dent_node *dent = NULL;
+ struct ubifs_zbranch *zbr;
+ union ubifs_key *dkey;
+
+ dbg_tnc_key(c, key, "%s",
+ ((nm && nm->name) ? (char *)nm->name : "(lowest)"));
+ ubifs_assert(type == UBIFS_DENT_KEY || type == UBIFS_XENT_KEY);
+
+ mutex_lock(&c->tnc_mutex);
+ found = lookup_level0(c, key, &znode, &n);
+ if (found < 0) {
+ err = found;
+ goto out;
+ }
+
+ /* Handle collisions */
+ if (found && nm && nm->name) {
+ err = resolve_collision(c, key, &znode, &n, nm);
+ if (err < 0)
+ goto out;
+ if (err == 0)
+ goto name_not_found;
+ }
+
+again:
+ /* Now find next entry */
+ err = tnc_next(c, &znode, &n);
+ if (err)
+ goto out;
+
+name_not_found:
+ dkey = &znode->zbranch[n].key;
+ zbr = &znode->zbranch[n];
+
+ if (key_ino(c, dkey) != key_ino(c, key) ||
+ key_type(c, dkey) != type) {
+ err = -ENOENT;
+ goto out;
+ }
+
+ if (!dent || dlen < zbr->len) {
+ kfree(dent);
+ dlen = zbr->len;
+ dent = kmalloc(dlen, GFP_NOFS);
+ if (!dent) {
+ err = -ENOMEM;
+ goto out;
+ }
+ }
+
+ err = tnc_read_node(c, zbr, dent);
+ if (err)
+ goto out;
+
+ if (dent->inum == 0)
+ goto again;
+
+ mutex_unlock(&c->tnc_mutex);
+ return dent;
+
+out:
+ kfree(dent);
+ mutex_unlock(&c->tnc_mutex);
+ return ERR_PTR(err);
+}
+
+/**
+ * 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.
+ */
+static struct ubifs_znode *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;
+}
+
+/**
+ * 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.
+ */
+static struct ubifs_znode *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 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 = 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 = tnc_postorder_next(zn);
+ }
+}
+
+/**
+ * tnc_destroy_cnext - destroy left-over obsolete znodes from a failed commit.
+ * @c: UBIFS file-system description object
+ *
+ * Destroy left-over obsolete znodes from a failed commit.
+ */
+static void tnc_destroy_cnext(struct ubifs_info *c)
+{
+ struct ubifs_znode *cnext;
+
+ if (!c->cnext)
+ return;
+ ubifs_assert(c->cmt_state == COMMIT_BROKEN);
+ cnext = c->cnext;
+ do {
+ struct ubifs_znode *znode = cnext;
+
+ cnext = cnext->cnext;
+ if (test_bit(OBSOLETE_ZNODE, &znode->flags))
+ kfree(znode);
+ } while (cnext != NULL && cnext != c->cnext);
+}
+
+/**
+ * ubifs_tnc_close - close TNC subsystem and free all related resources.
+ * @c: UBIFS file-system description object
+ */
+void ubifs_tnc_close(struct ubifs_info *c)
+{
+ long clean_freed;
+
+ tnc_destroy_cnext(c);
+ if (c->zroot.znode) {
+ clean_freed = ubifs_destroy_tnc_subtree(c->zroot.znode);
+ atomic_long_sub(clean_freed, &ubifs_clean_zn_cnt);
+ }
+ kfree(c->cbuf);
+ 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 znode.
+ * @c: UBIFS file-system description object
+ * @key: index node key
+ * @level: index node level
+ * @lnum: index node LEB number
+ * @offs: index node offset
+ *
+ * This function returns a pointer to the znode found or NULL if it is not
+ * found. A negative error code is returned on failure.
+ */
+static struct ubifs_znode *lookup_znode(struct ubifs_info *c,
+ union ubifs_key *key, int level,
+ int lnum, int offs)
+{
+ struct ubifs_znode *znode, *zn;
+ int n, nn;
+
+ /*
+ * The arguments have probably been read off flash, so don't assume
+ * they are valid.
+ */
+ if (level < 0)
+ return ERR_PTR(-EINVAL);
+
+ /* Get the root znode */
+ znode = c->zroot.znode;
+ if (!znode) {
+ znode = 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) {
+ search_zbranch(c, znode, key, &n);
+ if (n < 0)
+ return NULL;
+ 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 == NULL)
+ 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 == NULL)
+ break;
+ if (IS_ERR(znode))
+ return znode;
+ n = 0;
+ }
+ /* Check it */
+ if (znode->zbranch[n].lnum == lnum &&
+ znode->zbranch[n].offs == offs)
+ return get_znode(c, znode, n);
+ /* Stop if the key is greater than the one we are looking for */
+ if (keys_cmp(c, &znode->zbranch[n].key, key) > 0)
+ break;
+ }
+ return NULL;
+}
+
+/**
+ * is_idx_node_in_tnc - determine if an index node is in the TNC.
+ * @c: UBIFS file-system description object
+ * @key: key of index node
+ * @level: index node level
+ * @lnum: LEB number of index node
+ * @offs: offset of index node
+ *
+ * This function returns %0 if the index node is not referred to in the TNC.
+ * This function returns %1 if the index node is referred to in the TNC and the
+ * corresponding znode is dirty.
+ * This function returns %2 if an index node is referred to in the TNC and the
+ * corresponding znode is clean.
+ * Otherwise, this function returns a negative error code.
+ *
+ * For index nodes, the key is the key of the first child.
+ *
+ * This function relies on the fact that 0:0 is never a valid LEB number and
+ * offset for a main-area node.
+ */
+int is_idx_node_in_tnc(struct ubifs_info *c, union ubifs_key *key, int level,
+ int lnum, int offs)
+{
+ struct ubifs_znode *znode;
+
+ znode = lookup_znode(c, key, level, lnum, offs);
+ if (znode == NULL)
+ return 0;
+ if (IS_ERR(znode))
+ return PTR_ERR(znode);
+ if (ubifs_zn_dirty(znode))
+ return 1;
+ else
+ return 2;
+}
+
+/**
+ * is_node_clean - determine if a node is clean.
+ * @c: UBIFS file-system description object
+ * @key: node key
+ * @lnum: node LEB number
+ * @offs: node offset
+ *
+ * This function returns %1 if a node is referred to in the TNC and %0
+ * if it is not. Otherwise a negative error code is returned.
+ *
+ * This function relies on the fact that 0:0 is never a valid LEB number and
+ * offset for a main-area node.
+ */
+static int is_node_clean(struct ubifs_info *c, union ubifs_key *key,
+ int lnum, int offs)
+{
+ struct ubifs_zbranch *zbr;
+ struct ubifs_znode *znode, *zn;
+ int n, found, err, nn;
+ const int unique = !is_hash_key(c, key);
+
+ found = lookup_level0(c, key, &znode, &n);
+ if (found < 0)
+ return found; /* Error code */
+ if (!found)
+ return 0;
+ zbr = &znode->zbranch[n];
+ if (lnum == zbr->lnum && offs == zbr->offs)
+ return 1; /* Found it */
+ if (unique)
+ return 0;
+ /*
+ * Because the key is not unique, we have to look left
+ * and right as well
+ */
+ zn = znode;
+ nn = n;
+ /* Look left */
+ while (1) {
+ err = tnc_prev(c, &znode, &n);
+ if (err == -ENOENT)
+ break;
+ if (err)
+ return err;
+ if (keys_cmp(c, key, &znode->zbranch[n].key))
+ break;
+ zbr = &znode->zbranch[n];
+ if (lnum == zbr->lnum && offs == zbr->offs)
+ return 1; /* Found it */
+ }
+ /* Look right */
+ znode = zn;
+ n = nn;
+ while (1) {
+ err = tnc_next(c, &znode, &n);
+ if (err) {
+ if (err == -ENOENT)
+ return 0;
+ return err;
+ }
+ if (keys_cmp(c, key, &znode->zbranch[n].key))
+ break;
+ zbr = &znode->zbranch[n];
+ if (lnum == zbr->lnum && offs == zbr->offs)
+ return 1; /* Found it */
+ }
+ return 0;
+}
+
+/**
+ * ubifs_tnc_has_node - determine whether a node is in the TNC.
+ * @c: UBIFS file-system description object
+ * @key: node key
+ * @level: index node level (if it is an index node)
+ * @lnum: node LEB number
+ * @offs: node offset
+ * @is_idx: non-zero if the node is an index node
+ *
+ * This function returns %1 if a node is in the TNC and %0 if it is not.
+ * Otherwise a negative error code is returned.
+ * For index nodes, the key is the key of the first child.
+ * An index node is considered to be in the TNC only if the corresponding znode
+ * is clean or has not been loaded.
+ */
+int ubifs_tnc_has_node(struct ubifs_info *c, union ubifs_key *key, int level,
+ int lnum, int offs, int is_idx)
+{
+ int ret;
+
+ mutex_lock(&c->tnc_mutex);
+ if (is_idx) {
+ ret = is_idx_node_in_tnc(c, key, level, lnum, offs);
+ if (ret < 0)
+ goto out; /* Error code */
+ if (ret == 1)
+ /* The index node was found but it was dirty */
+ ret = 0;
+ else if (ret == 2)
+ /* The index node was found and it was clean */
+ ret = 1;
+ else if (ret != 0)
+ BUG();
+ } else
+ ret = is_node_clean(c, key, lnum, offs);
+out:
+ mutex_unlock(&c->tnc_mutex);
+ return ret;
+}
+
+/**
+ * ubifs_dirty_idx_node - dirty an index node.
+ * @c: UBIFS file-system description object
+ * @key: index node key
+ * @level: index node level
+ * @lnum: index node LEB number
+ * @offs: index node offset
+ *
+ * This function loads and dirties an index node so that it can be garbage
+ * collected.
+ *
+ * For index nodes, the key is the key of the first child.
+ *
+ * This function relies on the fact that 0:0 is never a valid LEB number and
+ * offset for a main-area node.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int ubifs_dirty_idx_node(struct ubifs_info *c, union ubifs_key *key, int level,
+ int lnum, int offs)
+{
+ struct ubifs_znode *znode;
+ int err = 0;
+
+ mutex_lock(&c->tnc_mutex);
+ znode = lookup_znode(c, key, level, lnum, offs);
+ if (!znode)
+ goto out;
+ if (IS_ERR(znode)) {
+ err = PTR_ERR(znode);
+ goto out;
+ }
+ znode = dirty_cow_bottom_up(c, znode);
+ if (IS_ERR(znode)) {
+ err = PTR_ERR(znode);
+ goto out;
+ }
+out:
+ mutex_unlock(&c->tnc_mutex);
+ return err;
+}
+
+#ifdef CONFIG_UBIFS_FS_DEBUG_CHK_TNC
+
+/**
+ * dbg_check_znode - check if znode is all right.
+ * @c: UBIFS file-system description object
+ * @zbr: zbranch which points to this znode
+ *
+ * This function makes sure that znode referred to by @zbr is all right.
+ * Returns zero if it is, and %-EINVAL if it is not.
+ */
+static int dbg_check_znode(const struct ubifs_info *c,
+ const struct ubifs_zbranch *zbr)
+{
+ const struct ubifs_znode *znode = zbr->znode;
+ const struct ubifs_znode *zp = znode->parent;
+ int n, err, cmp;
+
+ if (znode->child_cnt <= 0 || znode->child_cnt > c->fanout) {
+ err = 1;
+ goto out;
+ }
+ if (znode->level < 0) {
+ err = 2;
+ goto out;
+ }
+ if (znode->iip < 0 || znode->iip >= c->fanout) {
+ err = 3;
+ goto out;
+ }
+
+ if (zbr->len == 0)
+ /* Only dirty zbranch may have no on-flash nodes */
+ if (!ubifs_zn_dirty(znode)) {
+ err = 4;
+ goto out;
+ }
+
+ if (ubifs_zn_dirty(znode))
+ /* If znode is dirty, its parent has to be dirty as well */
+ if (zp && !ubifs_zn_dirty(zp))
+ /*
+ * The dirty flag is atomic and is cleared outside the
+ * TNC mutex, so znode's dirty flag may now have
+ * been cleared. The child is always cleared before the
+ * parent, so we just need to check again.
+ */
+ if (ubifs_zn_dirty(znode)) {
+ err = 5;
+ goto out;
+ }
+
+ if (zp) {
+ const union ubifs_key *min, *max;
+
+ if (znode->level != zp->level - 1) {
+ err = 6;
+ goto out;
+ }
+
+ /* Make sure the 'parent' pointer in our znode is correct */
+ err = search_zbranch(c, zp, &zbr->key, &n);
+ if (!err) {
+ /* This zbranch does not exist in the parent */
+ err = 7;
+ goto out;
+ }
+
+ if (znode->iip != n) {
+ err = 8;
+ goto out;
+ }
+
+ /*
+ * Make sure that the first key in our znode is greater than or
+ * equal to the key in the pointing zbranch.
+ */
+ min = &zbr->key;
+ cmp = keys_cmp(c, min, &znode->zbranch[0].key);
+ if (cmp == 1) {
+ err = 9;
+ goto out;
+ }
+
+ if (n + 1 < zp->child_cnt) {
+ max = &zp->zbranch[n + 1].key;
+
+ /*
+ * Make sure the last key in our znode is less than the
+ * the key in zbranch which goes after our pointing
+ * zbranch.
+ */
+ cmp = keys_cmp(c, max,
+ &znode->zbranch[znode->child_cnt - 1].key);
+ if (cmp == -1) {
+ err = 10;
+ goto out;
+ }
+ }
+ } else {
+ /* This may only be root znode */
+ if (zbr != &c->zroot) {
+ err = 11;
+ goto out;
+ }
+ }
+
+ /*
+ * Make sure that next key is greater or equivalent then the previous
+ * one.
+ */
+ for (n = 1; n < znode->child_cnt; n++) {
+ cmp = keys_cmp(c, &znode->zbranch[n].key,
+ &znode->zbranch[n - 1].key);
+ if (cmp < 0) {
+ err = 12;
+ goto out;
+ }
+ if (cmp == 0)
+ /* This can only be keys with colliding hash */
+ if (!is_hash_key(c, &znode->zbranch[n].key)) {
+ err = 13;
+ goto out;
+ }
+ }
+
+ for (n = 0; n < znode->child_cnt; n++) {
+ if (znode->zbranch[n].znode == NULL &&
+ (znode->zbranch[n].lnum == 0 ||
+ znode->zbranch[n].len == 0)) {
+ err = 14;
+ goto out;
+ }
+
+ if (znode->zbranch[n].lnum != 0 &&
+ znode->zbranch[n].len == 0) {
+ err = 15;
+ goto out;
+ }
+
+ if (znode->zbranch[n].lnum == 0 &&
+ znode->zbranch[n].len != 0) {
+ err = 16;
+ goto out;
+ }
+
+ if (znode->zbranch[n].lnum == 0 &&
+ znode->zbranch[n].offs != 0) {
+ err = 17;
+ goto out;
+ }
+
+ if (znode->level != 0 && znode->zbranch[n].znode)
+ if (znode->zbranch[n].znode->parent != znode) {
+ err = 18;
+ goto out;
+ }
+ }
+
+ return 0;
+
+out:
+ ubifs_err("failed, error %d", err);
+ ubifs_msg("dump of the znode");
+ dbg_dump_znode(c, znode);
+ if (zp) {
+ ubifs_msg("dump of the parent znode");
+ dbg_dump_znode(c, zp);
+ }
+ dump_stack();
+ return -EINVAL;
+}
+
+/**
+ * dbg_check_tnc - check TNC tree.
+ * @c: UBIFS file-system description object
+ * @extra: do extra checks that are possible at start commit
+ *
+ * This function traverses whole TNC tree and checks every znode. Returns zero
+ * if everything is all right and %-EINVAL if something is wrong with TNC.
+ */
+int dbg_check_tnc(struct ubifs_info *c, int extra)
+{
+ struct ubifs_znode *znode;
+ long clean_cnt = 0, dirty_cnt = 0;
+ int err;
+
+ ubifs_assert(mutex_is_locked(&c->tnc_mutex));
+ if (!c->zroot.znode)
+ return 0;
+
+ znode = tnc_postorder_first(c->zroot.znode);
+ while (znode) {
+ const struct ubifs_zbranch *zbr;
+
+ if (!znode->parent)
+ zbr = &c->zroot;
+ else
+ zbr = &znode->parent->zbranch[znode->iip];
+
+ err = dbg_check_znode(c, zbr);
+ if (err)
+ return err;
+
+ if (extra) {
+ if (ubifs_zn_dirty(znode))
+ dirty_cnt += 1;
+ else
+ clean_cnt += 1;
+ }
+
+ znode = tnc_postorder_next(znode);
+ }
+
+ if (extra) {
+ if (clean_cnt != atomic_long_read(&c->clean_zn_cnt)) {
+ ubifs_err("incorrect clean_zn_cnt %ld, calculated %ld",
+ atomic_long_read(&c->clean_zn_cnt),
+ clean_cnt);
+ return -EINVAL;
+ }
+ if (dirty_cnt != atomic_long_read(&c->dirty_zn_cnt)) {
+ ubifs_err("incorrect dirty_zn_cnt %ld, calculated %ld",
+ atomic_long_read(&c->dirty_zn_cnt),
+ dirty_cnt);
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
+#endif /* CONFIG_UBIFS_FS_DEBUG_CHK_TNC */
+
+#ifdef CONFIG_UBIFS_FS_DEBUG
+
+/**
+ * dbg_walk_sub_tree - walk index subtree.
+ * @c: UBIFS file-system description object
+ * @znode: root znode of the subtree to walk
+ * @leaf_cb: called for each leaf node
+ * @znode_cb: called for each indexing node
+ * @priv: private date which is passed to callbacks
+ *
+ * This is a helper function which recursively walks the UBIFS index, reading
+ * each indexing node from the media if needed. Returns zero in case of success
+ * and a negative error code in case of failure.
+ */
+static int dbg_walk_sub_tree(struct ubifs_info *c, struct ubifs_znode *znode,
+ dbg_leaf_callback leaf_cb,
+ dbg_znode_callback znode_cb, void *priv)
+{
+ int n, err;
+
+ cond_resched();
+
+ if (znode_cb) {
+ err = znode_cb(c, znode, priv);
+ if (err)
+ return err;
+ }
+
+ if (znode->level == 0) {
+ if (!leaf_cb)
+ return 0;
+
+ for (n = 0; n < znode->child_cnt; n++) {
+ struct ubifs_zbranch *zbr = &znode->zbranch[n];
+
+ err = leaf_cb(c, zbr, priv);
+ if (err)
+ return err;
+ }
+ } else
+ for (n = 0; n < znode->child_cnt; n++) {
+ struct ubifs_znode *zn;
+
+ zn = get_znode(c, znode, n);
+ if (IS_ERR(zn))
+ return PTR_ERR(zn);
+ err = dbg_walk_sub_tree(c, zn, leaf_cb, znode_cb, priv);
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
+/**
+ * dbg_walk_index - walk the on-flash index.
+ * @c: UBIFS file-system description object
+ * @leaf_cb: called for each leaf node
+ * @znode_cb: called for each indexing node
+ * @priv: private date which is passed to callbacks
+ *
+ * This function walks the UBIFS index and calls the @leaf_cb for each leaf
+ * node and @znode_cb for each indexing node. Returns zero in case of success
+ * and a negative error code in case of failure.
+ *
+ * Because 'dbg_walk_sub_tree()' is recursive, it runs the risk of exceeding the
+ * stack space.
+ *
+ * It would be better if this function removed every znode it pulled to into
+ * the TNC, so that the behaviour more closely matched the non-debugging
+ * behaviour.
+ */
+int dbg_walk_index(struct ubifs_info *c, dbg_leaf_callback leaf_cb,
+ dbg_znode_callback znode_cb, void *priv)
+{
+ int err = 0;
+
+ mutex_lock(&c->tnc_mutex);
+ if (!c->zroot.znode) {
+ c->zroot.znode = load_znode(c, &c->zroot, NULL, 0);
+ if (IS_ERR(c->zroot.znode)) {
+ err = PTR_ERR(c->zroot.znode);
+ c->zroot.znode = NULL;
+ goto out;
+ }
+ }
+
+ err = dbg_walk_sub_tree(c, c->zroot.znode, leaf_cb, znode_cb, priv);
+
+out:
+ mutex_unlock(&c->tnc_mutex);
+ return err;
+}
+
+/**
+ * dbg_read_leaf_nolock - read a leaf node.
+ * @c: UBIFS file-system description object
+ * @zbr: key and position of node
+ * @node: node returned
+ *
+ * This function reads leaf defined node by @zbr and returns zero in case of
+ * success or a negative negative error code in case of failure.
+ */
+int dbg_read_leaf_nolock(struct ubifs_info *c, struct ubifs_zbranch *zbr,
+ void *node)
+{
+ return tnc_read_node(c, zbr, node);
+}
+
+#endif /* CONFIG_UBIFS_FS_DEBUG */
+
+#ifdef CONFIG_UBIFS_FS_DEBUG_CHK_IDX_SZ
+
+static int dbg_add_size(struct ubifs_info *c, struct ubifs_znode *znode,
+ void *priv)
+{
+ long long *idx_size = priv;
+ int add;
+
+ add = ubifs_idx_node_sz(c, znode->child_cnt);
+ add = ALIGN(add, 8);
+ *idx_size += add;
+ return 0;
+}
+
+int dbg_check_idx_size(struct ubifs_info *c, long long idx_size)
+{
+ int err;
+ long long calc = 0;
+
+
+ err = dbg_walk_index(c, NULL, dbg_add_size, &calc);
+ if (err) {
+ ubifs_err("error %d while walking the index", err);
+ return err;
+ }
+
+ if (calc != idx_size) {
+ ubifs_err("index size check failed");
+ ubifs_err("calculated size is %lld, should be %lld",
+ calc, idx_size);
+ dump_stack();
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+#endif /* CONFIG_UBIFS_FS_DEBUG_CHK_IDX_SZ */
--
1.5.4.1
--
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