UBIFS: Implement read-only UBIFS support in U-Boot

The U-Boot UBIFS implementation is largely a direct copy from the current
Linux version (2.6.29-rc6). As already done in the UBI version we have an
"abstraction layer" to redefine or remove some OS calls (e.g. mutex_lock()
...). This makes it possible to use the original Linux code with very
little changes. And by this we can better update to later Linux versions.

I removed some of the Linux features that are not used in the U-Boot
version (e.g. garbage-collection, write support).

Signed-off-by: Stefan Roese <sr@denx.de>
CC: Artem Bityutskiy <dedekind@infradead.org>
CC: Adrian Hunter <ext-Adrian.Hunter@nokia.com>

1 files changed, 104 insertions, 0 deletions

diff --git a/fs/ubifs/log.c b/fs/ubifs/log.c
new file mode 100644
index 0000000..68a9bd9
--- /dev/null
+++ b/fs/ubifs/log.c
@@ -0,0 +1,104 @@
+/*
+ * 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"
+
+/**
+ * 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_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);
+}