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, 805 insertions, 0 deletions

diff --git a/fs/ubifs/log.c b/fs/ubifs/log.c
new file mode 100644
index 000000000000..36857b9ed59e
--- /dev/null
+++ b/fs/ubifs/log.c
@@ -0,0 +1,805 @@
+/*
+ * 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: Artem Bityutskiy (Битюцкий Артём)
+ *          Adrian Hunter
+ */
+
+/*
+ * This file is a part of UBIFS journal implementation and contains various
+ * functions which manipulate the log. The log is a fixed area on the flash
+ * which does not contain any data but refers to buds. The log is a part of the
+ * journal.
+ */
+
+#include "ubifs.h"
+
+#ifdef CONFIG_UBIFS_FS_DEBUG
+static int dbg_check_bud_bytes(struct ubifs_info *c);
+#else
+#define dbg_check_bud_bytes(c) 0
+#endif
+
+/**
+ * ubifs_search_bud - search bud LEB.
+ * @c: UBIFS file-system description object
+ * @lnum: logical eraseblock number to search
+ *
+ * This function searches bud LEB @lnum. Returns bud description object in case
+ * of success and %NULL if there is no bud with this LEB number.
+ */
+struct ubifs_bud *ubifs_search_bud(struct ubifs_info *c, int lnum)
+{
+        struct rb_node *p;
+        struct ubifs_bud *bud;
+
+        spin_lock(&c->buds_lock);
+        p = c->buds.rb_node;
+        while (p) {
+                bud = rb_entry(p, struct ubifs_bud, rb);
+                if (lnum < bud->lnum)
+                        p = p->rb_left;
+                else if (lnum > bud->lnum)
+                        p = p->rb_right;
+                else {
+                        spin_unlock(&c->buds_lock);
+                        return bud;
+                }
+        }
+        spin_unlock(&c->buds_lock);
+        return NULL;
+}
+
+/**
+ * ubifs_get_wbuf - get the wbuf associated with a LEB, if there is one.
+ * @c: UBIFS file-system description object
+ * @lnum: logical eraseblock number to search
+ *
+ * This functions returns the wbuf for @lnum or %NULL if there is not one.
+ */
+struct ubifs_wbuf *ubifs_get_wbuf(struct ubifs_info *c, int lnum)
+{
+        struct rb_node *p;
+        struct ubifs_bud *bud;
+        int jhead;
+
+        if (!c->jheads)
+                return NULL;
+
+        spin_lock(&c->buds_lock);
+        p = c->buds.rb_node;
+        while (p) {
+                bud = rb_entry(p, struct ubifs_bud, rb);
+                if (lnum < bud->lnum)
+                        p = p->rb_left;
+                else if (lnum > bud->lnum)
+                        p = p->rb_right;
+                else {
+                        jhead = bud->jhead;
+                        spin_unlock(&c->buds_lock);
+                        return &c->jheads[jhead].wbuf;
+                }
+        }
+        spin_unlock(&c->buds_lock);
+        return NULL;
+}
+
+/**
+ * next_log_lnum - switch to the next log LEB.
+ * @c: UBIFS file-system description object
+ * @lnum: current log LEB
+ */
+static inline int next_log_lnum(const struct ubifs_info *c, int lnum)
+{
+        lnum += 1;
+        if (lnum > c->log_last)
+                lnum = UBIFS_LOG_LNUM;
+
+        return lnum;
+}
+
+/**
+ * empty_log_bytes - calculate amount of empty space in the log.
+ * @c: UBIFS file-system description object
+ */
+static inline long long empty_log_bytes(const struct ubifs_info *c)
+{
+        long long h, t;
+
+        h = (long long)c->lhead_lnum * c->leb_size + c->lhead_offs;
+        t = (long long)c->ltail_lnum * c->leb_size;
+
+        if (h >= t)
+                return c->log_bytes - h + t;
+        else
+                return t - h;
+}
+
+/**
+ * ubifs_add_bud - add bud LEB to the tree of buds and its journal head list.
+ * @c: UBIFS file-system description object
+ * @bud: the bud to add
+ */
+void ubifs_add_bud(struct ubifs_info *c, struct ubifs_bud *bud)
+{
+        struct rb_node **p, *parent = NULL;
+        struct ubifs_bud *b;
+        struct ubifs_jhead *jhead;
+
+        spin_lock(&c->buds_lock);
+        p = &c->buds.rb_node;
+        while (*p) {
+                parent = *p;
+                b = rb_entry(parent, struct ubifs_bud, rb);
+                ubifs_assert(bud->lnum != b->lnum);
+                if (bud->lnum < b->lnum)
+                        p = &(*p)->rb_left;
+                else
+                        p = &(*p)->rb_right;
+        }
+
+        rb_link_node(&bud->rb, parent, p);
+        rb_insert_color(&bud->rb, &c->buds);
+        if (c->jheads) {
+                jhead = &c->jheads[bud->jhead];
+                list_add_tail(&bud->list, &jhead->buds_list);
+        } else
+                ubifs_assert(c->replaying && (c->vfs_sb->s_flags & MS_RDONLY));
+
+        /*
+         * Note, although this is a new bud, we anyway account this space now,
+         * before any data has been written to it, because this is about to
+         * guarantee fixed mount time, and this bud will anyway be read and
+         * scanned.
+         */
+        c->bud_bytes += c->leb_size - bud->start;
+
+        dbg_log("LEB %d:%d, jhead %d, bud_bytes %lld", bud->lnum,
+                bud->start, bud->jhead, c->bud_bytes);
+        spin_unlock(&c->buds_lock);
+}
+
+/**
+ * ubifs_create_buds_lists - create journal head buds lists for remount rw.
+ * @c: UBIFS file-system description object
+ */
+void ubifs_create_buds_lists(struct ubifs_info *c)
+{
+        struct rb_node *p;
+
+        spin_lock(&c->buds_lock);
+        p = rb_first(&c->buds);
+        while (p) {
+                struct ubifs_bud *bud = rb_entry(p, struct ubifs_bud, rb);
+                struct ubifs_jhead *jhead = &c->jheads[bud->jhead];
+
+                list_add_tail(&bud->list, &jhead->buds_list);
+                p = rb_next(p);
+        }
+        spin_unlock(&c->buds_lock);
+}
+
+/**
+ * ubifs_add_bud_to_log - add a new bud to the log.
+ * @c: UBIFS file-system description object
+ * @jhead: journal head the bud belongs to
+ * @lnum: LEB number of the bud
+ * @offs: starting offset of the bud
+ *
+ * This function writes reference node for the new bud LEB @lnum it to the log,
+ * and adds it to the buds tress. It also makes sure that log size does not
+ * exceed the 'c->max_bud_bytes' limit. Returns zero in case of success,
+ * %-EAGAIN if commit is required, and a negative error codes in case of
+ * failure.
+ */
+int ubifs_add_bud_to_log(struct ubifs_info *c, int jhead, int lnum, int offs)
+{
+        int err;
+        struct ubifs_bud *bud;
+        struct ubifs_ref_node *ref;
+
+        bud = kmalloc(sizeof(struct ubifs_bud), GFP_NOFS);
+        if (!bud)
+                return -ENOMEM;
+        ref = kzalloc(c->ref_node_alsz, GFP_NOFS);
+        if (!ref) {
+                kfree(bud);
+                return -ENOMEM;
+        }
+
+        mutex_lock(&c->log_mutex);
+
+        if (c->ro_media) {
+                err = -EROFS;
+                goto out_unlock;
+        }
+
+        /* Make sure we have enough space in the log */
+        if (empty_log_bytes(c) - c->ref_node_alsz < c->min_log_bytes) {
+                dbg_log("not enough log space - %lld, required %d",
+                        empty_log_bytes(c), c->min_log_bytes);
+                ubifs_commit_required(c);
+                err = -EAGAIN;
+                goto out_unlock;
+        }
+
+        /*
+         * Make sure the the amount of space in buds will not exceed
+         * 'c->max_bud_bytes' limit, because we want to guarantee mount time
+         * limits.
+         *
+         * It is not necessary to hold @c->buds_lock when reading @c->bud_bytes
+         * because we are holding @c->log_mutex. All @c->bud_bytes take place
+         * when both @c->log_mutex and @c->bud_bytes are locked.
+         */
+        if (c->bud_bytes + c->leb_size - offs > c->max_bud_bytes) {
+                dbg_log("bud bytes %lld (%lld max), require commit",
+                        c->bud_bytes, c->max_bud_bytes);
+                ubifs_commit_required(c);
+                err = -EAGAIN;
+                goto out_unlock;
+        }
+
+        /*
+         * If the journal is full enough - start background commit. Note, it is
+         * OK to read 'c->cmt_state' without spinlock because integer reads
+         * are atomic in the kernel.
+         */
+        if (c->bud_bytes >= c->bg_bud_bytes &&
+            c->cmt_state == COMMIT_RESTING) {
+                dbg_log("bud bytes %lld (%lld max), initiate BG commit",
+                        c->bud_bytes, c->max_bud_bytes);
+                ubifs_request_bg_commit(c);
+        }
+
+        bud->lnum = lnum;
+        bud->start = offs;
+        bud->jhead = jhead;
+
+        ref->ch.node_type = UBIFS_REF_NODE;
+        ref->lnum = cpu_to_le32(bud->lnum);
+        ref->offs = cpu_to_le32(bud->start);
+        ref->jhead = cpu_to_le32(jhead);
+
+        if (c->lhead_offs > c->leb_size - c->ref_node_alsz) {
+                c->lhead_lnum = next_log_lnum(c, c->lhead_lnum);
+                c->lhead_offs = 0;
+        }
+
+        if (c->lhead_offs == 0) {
+                /* Must ensure next log LEB has been unmapped */
+                err = ubifs_leb_unmap(c, c->lhead_lnum);
+                if (err)
+                        goto out_unlock;
+        }
+
+        if (bud->start == 0) {
+                /*
+                 * Before writing the LEB reference which refers an empty LEB
+                 * to the log, we have to make sure it is mapped, because
+                 * otherwise we'd risk to refer an LEB with garbage in case of
+                 * an unclean reboot, because the target LEB might have been
+                 * unmapped, but not yet physically erased.
+                 */
+                err = ubi_leb_map(c->ubi, bud->lnum, UBI_SHORTTERM);
+                if (err)
+                        goto out_unlock;
+        }
+
+        dbg_log("write ref LEB %d:%d",
+                c->lhead_lnum, c->lhead_offs);
+        err = ubifs_write_node(c, ref, UBIFS_REF_NODE_SZ, c->lhead_lnum,
+                               c->lhead_offs, UBI_SHORTTERM);
+        if (err)
+                goto out_unlock;
+
+        c->lhead_offs += c->ref_node_alsz;
+
+        ubifs_add_bud(c, bud);
+
+        mutex_unlock(&c->log_mutex);
+        kfree(ref);
+        return 0;
+
+out_unlock:
+        mutex_unlock(&c->log_mutex);
+        kfree(ref);
+        kfree(bud);
+        return err;
+}
+
+/**
+ * remove_buds - remove used buds.
+ * @c: UBIFS file-system description object
+ *
+ * This function removes use buds from the buds tree. It does not remove the
+ * buds which are pointed to by journal heads.
+ */
+static void remove_buds(struct ubifs_info *c)
+{
+        struct rb_node *p;
+
+        ubifs_assert(list_empty(&c->old_buds));
+        c->cmt_bud_bytes = 0;
+        spin_lock(&c->buds_lock);
+        p = rb_first(&c->buds);
+        while (p) {
+                struct rb_node *p1 = p;
+                struct ubifs_bud *bud;
+                struct ubifs_wbuf *wbuf;
+
+                p = rb_next(p);
+                bud = rb_entry(p1, struct ubifs_bud, rb);
+                wbuf = &c->jheads[bud->jhead].wbuf;
+
+                if (wbuf->lnum == bud->lnum) {
+                        /*
+                         * Do not remove buds which are pointed to by journal
+                         * heads (non-closed buds).
+                         */
+                        c->cmt_bud_bytes += wbuf->offs - bud->start;
+                        dbg_log("preserve %d:%d, jhead %d, bud bytes %d, "
+                                "cmt_bud_bytes %lld", bud->lnum, bud->start,
+                                bud->jhead, wbuf->offs - bud->start,
+                                c->cmt_bud_bytes);
+                        bud->start = wbuf->offs;
+                } else {
+                        c->cmt_bud_bytes += c->leb_size - bud->start;
+                        dbg_log("remove %d:%d, jhead %d, bud bytes %d, "
+                                "cmt_bud_bytes %lld", bud->lnum, bud->start,
+                                bud->jhead, c->leb_size - bud->start,
+                                c->cmt_bud_bytes);
+                        rb_erase(p1, &c->buds);
+                        list_del(&bud->list);
+                        /*
+                         * If the commit does not finish, the recovery will need
+                         * to replay the journal, in which case the old buds
+                         * must be unchanged. Do not release them until post
+                         * commit i.e. do not allow them to be garbage
+                         * collected.
+                         */
+                        list_add(&bud->list, &c->old_buds);
+                }
+        }
+        spin_unlock(&c->buds_lock);
+}
+
+/**
+ * ubifs_log_start_commit - start commit.
+ * @c: UBIFS file-system description object
+ * @ltail_lnum: return new log tail LEB number
+ *
+ * The commit operation starts with writing "commit start" node to the log and
+ * reference nodes for all journal heads which will define new journal after
+ * the commit has been finished. The commit start and reference nodes are
+ * written in one go to the nearest empty log LEB (hence, when commit is
+ * finished UBIFS may safely unmap all the previous log LEBs). This function
+ * returns zero in case of success and a negative error code in case of
+ * failure.
+ */
+int ubifs_log_start_commit(struct ubifs_info *c, int *ltail_lnum)
+{
+        void *buf;
+        struct ubifs_cs_node *cs;
+        struct ubifs_ref_node *ref;
+        int err, i, max_len, len;
+
+        err = dbg_check_bud_bytes(c);
+        if (err)
+                return err;
+
+        max_len = UBIFS_CS_NODE_SZ + c->jhead_cnt * UBIFS_REF_NODE_SZ;
+        max_len = ALIGN(max_len, c->min_io_size);
+        buf = cs = kmalloc(max_len, GFP_NOFS);
+        if (!buf)
+                return -ENOMEM;
+
+        cs->ch.node_type = UBIFS_CS_NODE;
+        cs->cmt_no = cpu_to_le64(c->cmt_no + 1);
+        ubifs_prepare_node(c, cs, UBIFS_CS_NODE_SZ, 0);
+
+        /*
+         * Note, we do not lock 'c->log_mutex' because this is the commit start
+         * phase and we are exclusively using the log. And we do not lock
+         * write-buffer because nobody can write to the file-system at this
+         * phase.
+         */
+
+        len = UBIFS_CS_NODE_SZ;
+        for (i = 0; i < c->jhead_cnt; i++) {
+                int lnum = c->jheads[i].wbuf.lnum;
+                int offs = c->jheads[i].wbuf.offs;
+
+                if (lnum == -1 || offs == c->leb_size)
+                        continue;
+
+                dbg_log("add ref to LEB %d:%d for jhead %d", lnum, offs, i);
+                ref = buf + len;
+                ref->ch.node_type = UBIFS_REF_NODE;
+                ref->lnum = cpu_to_le32(lnum);
+                ref->offs = cpu_to_le32(offs);
+                ref->jhead = cpu_to_le32(i);
+
+                ubifs_prepare_node(c, ref, UBIFS_REF_NODE_SZ, 0);
+                len += UBIFS_REF_NODE_SZ;
+        }
+
+        ubifs_pad(c, buf + len, ALIGN(len, c->min_io_size) - len);
+
+        /* Switch to the next log LEB */
+        if (c->lhead_offs) {
+                c->lhead_lnum = next_log_lnum(c, c->lhead_lnum);
+                c->lhead_offs = 0;
+        }
+
+        if (c->lhead_offs == 0) {
+                /* Must ensure next LEB has been unmapped */
+                err = ubifs_leb_unmap(c, c->lhead_lnum);
+                if (err)
+                        goto out;
+        }
+
+        len = ALIGN(len, c->min_io_size);
+        dbg_log("writing commit start at LEB %d:0, len %d", c->lhead_lnum, len);
+        err = ubifs_leb_write(c, c->lhead_lnum, cs, 0, len, UBI_SHORTTERM);
+        if (err)
+                goto out;
+
+        *ltail_lnum = c->lhead_lnum;
+
+        c->lhead_offs += len;
+        if (c->lhead_offs == c->leb_size) {
+                c->lhead_lnum = next_log_lnum(c, c->lhead_lnum);
+                c->lhead_offs = 0;
+        }
+
+        remove_buds(c);
+
+        /*
+         * We have started the commit and now users may use the rest of the log
+         * for new writes.
+         */
+        c->min_log_bytes = 0;
+
+out:
+        kfree(buf);
+        return err;
+}
+
+/**
+ * ubifs_log_end_commit - end commit.
+ * @c: UBIFS file-system description object
+ * @ltail_lnum: new log tail LEB number
+ *
+ * This function is called on when the commit operation was finished. It
+ * moves log tail to new position and unmaps LEBs which contain obsolete data.
+ * Returns zero in case of success and a negative error code in case of
+ * failure.
+ */
+int ubifs_log_end_commit(struct ubifs_info *c, int ltail_lnum)
+{
+        int err;
+
+        /*
+         * At this phase we have to lock 'c->log_mutex' because UBIFS allows FS
+         * writes during commit. Its only short "commit" start phase when
+         * writers are blocked.
+         */
+        mutex_lock(&c->log_mutex);
+
+        dbg_log("old tail was LEB %d:0, new tail is LEB %d:0",
+                c->ltail_lnum, ltail_lnum);
+
+        c->ltail_lnum = ltail_lnum;
+        /*
+         * The commit is finished and from now on it must be guaranteed that
+         * there is always enough space for the next commit.
+         */
+        c->min_log_bytes = c->leb_size;
+
+        spin_lock(&c->buds_lock);
+        c->bud_bytes -= c->cmt_bud_bytes;
+        spin_unlock(&c->buds_lock);
+
+        err = dbg_check_bud_bytes(c);
+
+        mutex_unlock(&c->log_mutex);
+        return err;
+}
+
+/**
+ * ubifs_log_post_commit - things to do after commit is completed.
+ * @c: UBIFS file-system description object
+ * @old_ltail_lnum: old log tail LEB number
+ *
+ * Release buds only after commit is completed, because they must be unchanged
+ * if recovery is needed.
+ *
+ * Unmap log LEBs only after commit is completed, because they may be needed for
+ * recovery.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int ubifs_log_post_commit(struct ubifs_info *c, int old_ltail_lnum)
+{
+        int lnum, err = 0;
+
+        while (!list_empty(&c->old_buds)) {
+                struct ubifs_bud *bud;
+
+                bud = list_entry(c->old_buds.next, struct ubifs_bud, list);
+                err = ubifs_return_leb(c, bud->lnum);
+                if (err)
+                        return err;
+                list_del(&bud->list);
+                kfree(bud);
+        }
+        mutex_lock(&c->log_mutex);
+        for (lnum = old_ltail_lnum; lnum != c->ltail_lnum;
+             lnum = next_log_lnum(c, lnum)) {
+                dbg_log("unmap log LEB %d", lnum);
+                err = ubifs_leb_unmap(c, lnum);
+                if (err)
+                        goto out;
+        }
+out:
+        mutex_unlock(&c->log_mutex);
+        return err;
+}
+
+/**
+ * struct done_ref - references that have been done.
+ * @rb: rb-tree node
+ * @lnum: LEB number
+ */
+struct done_ref {
+        struct rb_node rb;
+        int lnum;
+};
+
+/**
+ * done_already - determine if a reference has been done already.
+ * @done_tree: rb-tree to store references that have been done
+ * @lnum: LEB number of reference
+ *
+ * This function returns %1 if the reference has been done, %0 if not, otherwise
+ * a negative error code is returned.
+ */
+static int done_already(struct rb_root *done_tree, int lnum)
+{
+        struct rb_node **p = &done_tree->rb_node, *parent = NULL;
+        struct done_ref *dr;
+
+        while (*p) {
+                parent = *p;
+                dr = rb_entry(parent, struct done_ref, rb);
+                if (lnum < dr->lnum)
+                        p = &(*p)->rb_left;
+                else if (lnum > dr->lnum)
+                        p = &(*p)->rb_right;
+                else
+                        return 1;
+        }
+
+        dr = kzalloc(sizeof(struct done_ref), GFP_NOFS);
+        if (!dr)
+                return -ENOMEM;
+
+        dr->lnum = lnum;
+
+        rb_link_node(&dr->rb, parent, p);
+        rb_insert_color(&dr->rb, done_tree);
+
+        return 0;
+}
+
+/**
+ * destroy_done_tree - destroy the done tree.
+ * @done_tree: done tree to destroy
+ */
+static void destroy_done_tree(struct rb_root *done_tree)
+{
+        struct rb_node *this = done_tree->rb_node;
+        struct done_ref *dr;
+
+        while (this) {
+                if (this->rb_left) {
+                        this = this->rb_left;
+                        continue;
+                } else if (this->rb_right) {
+                        this = this->rb_right;
+                        continue;
+                }
+                dr = rb_entry(this, struct done_ref, rb);
+                this = rb_parent(this);
+                if (this) {
+                        if (this->rb_left == &dr->rb)
+                                this->rb_left = NULL;
+                        else
+                                this->rb_right = NULL;
+                }
+                kfree(dr);
+        }
+}
+
+/**
+ * add_node - add a node to the consolidated log.
+ * @c: UBIFS file-system description object
+ * @buf: buffer to which to add
+ * @lnum: LEB number to which to write is passed and returned here
+ * @offs: offset to where to write is passed and returned here
+ * @node: node to add
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int add_node(struct ubifs_info *c, void *buf, int *lnum, int *offs,
+                    void *node)
+{
+        struct ubifs_ch *ch = node;
+        int len = le32_to_cpu(ch->len), remains = c->leb_size - *offs;
+
+        if (len > remains) {
+                int sz = ALIGN(*offs, c->min_io_size), err;
+
+                ubifs_pad(c, buf + *offs, sz - *offs);
+                err = ubifs_leb_change(c, *lnum, buf, sz, UBI_SHORTTERM);
+                if (err)
+                        return err;
+                *lnum = next_log_lnum(c, *lnum);
+                *offs = 0;
+        }
+        memcpy(buf + *offs, node, len);
+        *offs += ALIGN(len, 8);
+        return 0;
+}
+
+/**
+ * ubifs_consolidate_log - consolidate the log.
+ * @c: UBIFS file-system description object
+ *
+ * Repeated failed commits could cause the log to be full, but at least 1 LEB is
+ * needed for commit. This function rewrites the reference nodes in the log
+ * omitting duplicates, and failed CS nodes, and leaving no gaps.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int ubifs_consolidate_log(struct ubifs_info *c)
+{
+        struct ubifs_scan_leb *sleb;
+        struct ubifs_scan_node *snod;
+        struct rb_root done_tree = RB_ROOT;
+        int lnum, err, first = 1, write_lnum, offs = 0;
+        void *buf;
+
+        dbg_rcvry("log tail LEB %d, log head LEB %d", c->ltail_lnum,
+                  c->lhead_lnum);
+        buf = vmalloc(c->leb_size);
+        if (!buf)
+                return -ENOMEM;
+        lnum = c->ltail_lnum;
+        write_lnum = lnum;
+        while (1) {
+                sleb = ubifs_scan(c, lnum, 0, c->sbuf);
+                if (IS_ERR(sleb)) {
+                        err = PTR_ERR(sleb);
+                        goto out_free;
+                }
+                list_for_each_entry(snod, &sleb->nodes, list) {
+                        switch (snod->type) {
+                        case UBIFS_REF_NODE: {
+                                struct ubifs_ref_node *ref = snod->node;
+                                int ref_lnum = le32_to_cpu(ref->lnum);
+
+                                err = done_already(&done_tree, ref_lnum);
+                                if (err < 0)
+                                        goto out_scan;
+                                if (err != 1) {
+                                        err = add_node(c, buf, &write_lnum,
+                                                       &offs, snod->node);
+                                        if (err)
+                                                goto out_scan;
+                                }
+                                break;
+                        }
+                        case UBIFS_CS_NODE:
+                                if (!first)
+                                        break;
+                                err = add_node(c, buf, &write_lnum, &offs,
+                                               snod->node);
+                                if (err)
+                                        goto out_scan;
+                                first = 0;
+                                break;
+                        }
+                }
+                ubifs_scan_destroy(sleb);
+                if (lnum == c->lhead_lnum)
+                        break;
+                lnum = next_log_lnum(c, lnum);
+        }
+        if (offs) {
+                int sz = ALIGN(offs, c->min_io_size);
+
+                ubifs_pad(c, buf + offs, sz - offs);
+                err = ubifs_leb_change(c, write_lnum, buf, sz, UBI_SHORTTERM);
+                if (err)
+                        goto out_free;
+                offs = ALIGN(offs, c->min_io_size);
+        }
+        destroy_done_tree(&done_tree);
+        vfree(buf);
+        if (write_lnum == c->lhead_lnum) {
+                ubifs_err("log is too full");
+                return -EINVAL;
+        }
+        /* Unmap remaining LEBs */
+        lnum = write_lnum;
+        do {
+                lnum = next_log_lnum(c, lnum);
+                err = ubifs_leb_unmap(c, lnum);
+                if (err)
+                        return err;
+        } while (lnum != c->lhead_lnum);
+        c->lhead_lnum = write_lnum;
+        c->lhead_offs = offs;
+        dbg_rcvry("new log head at %d:%d", c->lhead_lnum, c->lhead_offs);
+        return 0;
+
+out_scan:
+        ubifs_scan_destroy(sleb);
+out_free:
+        destroy_done_tree(&done_tree);
+        vfree(buf);
+        return err;
+}
+
+#ifdef CONFIG_UBIFS_FS_DEBUG
+
+/**
+ * dbg_check_bud_bytes - make sure bud bytes calculation are all right.
+ * @c: UBIFS file-system description object
+ *
+ * This function makes sure the amount of flash space used by closed buds
+ * ('c->bud_bytes' is correct). Returns zero in case of success and %-EINVAL in
+ * case of failure.
+ */
+static int dbg_check_bud_bytes(struct ubifs_info *c)
+{
+        int i, err = 0;
+        struct ubifs_bud *bud;
+        long long bud_bytes = 0;
+
+        if (!(ubifs_chk_flags & UBIFS_CHK_GEN))
+                return 0;
+
+        spin_lock(&c->buds_lock);
+        for (i = 0; i < c->jhead_cnt; i++)
+                list_for_each_entry(bud, &c->jheads[i].buds_list, list)
+                        bud_bytes += c->leb_size - bud->start;
+
+        if (c->bud_bytes != bud_bytes) {
+                ubifs_err("bad bud_bytes %lld, calculated %lld",
+                          c->bud_bytes, bud_bytes);
+                err = -EINVAL;
+        }
+        spin_unlock(&c->buds_lock);
+
+        return err;
+}
+
+#endif /* CONFIG_UBIFS_FS_DEBUG */