Reconstruct source directory tree.

1 files changed, 267 insertions, 0 deletions

diff --git a/src/ext4_super.c b/src/ext4_super.c
new file mode 100644
index 0000000..582d1fb
--- /dev/null
+++ b/src/ext4_super.c
@@ -0,0 +1,267 @@
+/*
+ * Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)
+ *
+ *
+ * HelenOS:
+ * Copyright (c) 2012 Martin Sucha
+ * Copyright (c) 2012 Frantisek Princ
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * - The name of the author may not be used to endorse or promote products
+ *   derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/** @addtogroup lwext4
+ * @{
+ */
+/**
+ * @file  ext4_super.h
+ * @brief Superblock operations.
+ */
+
+#include "ext4_config.h"
+#include "ext4_super.h"
+#include "ext4_crc32.h"
+
+uint32_t ext4_block_group_cnt(struct ext4_sblock *s)
+{
+	uint64_t blocks_count = ext4_sb_get_blocks_cnt(s);
+	uint32_t blocks_per_group = ext4_get32(s, blocks_per_group);
+
+	uint32_t block_groups_count = (uint32_t)(blocks_count / blocks_per_group);
+
+	if (blocks_count % blocks_per_group)
+		block_groups_count++;
+
+	return block_groups_count;
+}
+
+uint32_t ext4_blocks_in_group_cnt(struct ext4_sblock *s, uint32_t bgid)
+{
+	uint32_t block_group_count = ext4_block_group_cnt(s);
+	uint32_t blocks_per_group = ext4_get32(s, blocks_per_group);
+	uint64_t total_blocks = ext4_sb_get_blocks_cnt(s);
+
+	if (bgid < block_group_count - 1)
+		return blocks_per_group;
+
+	return (uint32_t)(total_blocks - ((block_group_count - 1) * blocks_per_group));
+}
+
+uint32_t ext4_inodes_in_group_cnt(struct ext4_sblock *s, uint32_t bgid)
+{
+	uint32_t block_group_count = ext4_block_group_cnt(s);
+	uint32_t inodes_per_group = ext4_get32(s, inodes_per_group);
+	uint32_t total_inodes = ext4_get32(s, inodes_count);
+
+	if (bgid < block_group_count - 1)
+		return inodes_per_group;
+
+	return (total_inodes - ((block_group_count - 1) * inodes_per_group));
+}
+
+#if CONFIG_META_CSUM_ENABLE
+static uint32_t ext4_sb_csum(struct ext4_sblock *s)
+{
+
+	return ext4_crc32c(EXT4_CRC32_INIT, s,
+			offsetof(struct ext4_sblock, checksum));
+}
+#else
+#define ext4_sb_csum(...) 0
+#endif
+
+static bool ext4_sb_verify_csum(struct ext4_sblock *s)
+{
+	if (!ext4_sb_feature_ro_com(s, EXT4_FRO_COM_METADATA_CSUM))
+		return true;
+
+	if (s->checksum_type != to_le32(EXT4_CHECKSUM_CRC32C))
+		return false;
+
+	return s->checksum == to_le32(ext4_sb_csum(s));
+}
+
+static void ext4_sb_set_csum(struct ext4_sblock *s)
+{
+	if (!ext4_sb_feature_ro_com(s, EXT4_FRO_COM_METADATA_CSUM))
+		return;
+
+	s->checksum = to_le32(ext4_sb_csum(s));
+}
+
+int ext4_sb_write(struct ext4_blockdev *bdev, struct ext4_sblock *s)
+{
+	ext4_sb_set_csum(s);
+	return ext4_block_writebytes(bdev, EXT4_SUPERBLOCK_OFFSET, s,
+				     EXT4_SUPERBLOCK_SIZE);
+}
+
+int ext4_sb_read(struct ext4_blockdev *bdev, struct ext4_sblock *s)
+{
+	return ext4_block_readbytes(bdev, EXT4_SUPERBLOCK_OFFSET, s,
+				    EXT4_SUPERBLOCK_SIZE);
+}
+
+bool ext4_sb_check(struct ext4_sblock *s)
+{
+	if (ext4_get16(s, magic) != EXT4_SUPERBLOCK_MAGIC)
+		return false;
+
+	if (ext4_get32(s, inodes_count) == 0)
+		return false;
+
+	if (ext4_sb_get_blocks_cnt(s) == 0)
+		return false;
+
+	if (ext4_get32(s, blocks_per_group) == 0)
+		return false;
+
+	if (ext4_get32(s, inodes_per_group) == 0)
+		return false;
+
+	if (ext4_get16(s, inode_size) < 128)
+		return false;
+
+	if (ext4_get32(s, first_inode) < 11)
+		return false;
+
+	if (ext4_sb_get_desc_size(s) < EXT4_MIN_BLOCK_GROUP_DESCRIPTOR_SIZE)
+		return false;
+
+	if (ext4_sb_get_desc_size(s) > EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
+		return false;
+
+	if (!ext4_sb_verify_csum(s))
+		return false;
+
+	return true;
+}
+
+static inline int is_power_of(uint32_t a, uint32_t b)
+{
+	while (1) {
+		if (a < b)
+			return 0;
+		if (a == b)
+			return 1;
+		if ((a % b) != 0)
+			return 0;
+		a = a / b;
+	}
+}
+
+bool ext4_sb_sparse(uint32_t group)
+{
+	if (group <= 1)
+		return 1;
+
+	if (!(group & 1))
+		return 0;
+
+	return (is_power_of(group, 7) || is_power_of(group, 5) ||
+		is_power_of(group, 3));
+}
+
+bool ext4_sb_is_super_in_bg(struct ext4_sblock *s, uint32_t group)
+{
+	if (ext4_sb_feature_ro_com(s, EXT4_FRO_COM_SPARSE_SUPER) &&
+	    !ext4_sb_sparse(group))
+		return false;
+	return true;
+}
+
+static uint32_t ext4_bg_num_gdb_meta(struct ext4_sblock *s, uint32_t group)
+{
+	uint32_t dsc_per_block =
+	    ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s);
+
+	uint32_t metagroup = group / dsc_per_block;
+	uint32_t first = metagroup * dsc_per_block;
+	uint32_t last = first + dsc_per_block - 1;
+
+	if (group == first || group == first + 1 || group == last)
+		return 1;
+	return 0;
+}
+
+static uint32_t ext4_bg_num_gdb_nometa(struct ext4_sblock *s, uint32_t group)
+{
+	if (!ext4_sb_is_super_in_bg(s, group))
+		return 0;
+	uint32_t dsc_per_block =
+	    ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s);
+
+	uint32_t db_count =
+	    (ext4_block_group_cnt(s) + dsc_per_block - 1) / dsc_per_block;
+
+	if (ext4_sb_feature_incom(s, EXT4_FINCOM_META_BG))
+		return ext4_sb_first_meta_bg(s);
+
+	return db_count;
+}
+
+uint32_t ext4_bg_num_gdb(struct ext4_sblock *s, uint32_t group)
+{
+	uint32_t dsc_per_block =
+	    ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s);
+	uint32_t first_meta_bg = ext4_sb_first_meta_bg(s);
+	uint32_t metagroup = group / dsc_per_block;
+
+	if (!ext4_sb_feature_incom(s,EXT4_FINCOM_META_BG) ||
+	    metagroup < first_meta_bg)
+		return ext4_bg_num_gdb_nometa(s, group);
+
+	return ext4_bg_num_gdb_meta(s, group);
+}
+
+uint32_t ext4_num_base_meta_clusters(struct ext4_sblock *s,
+				     uint32_t block_group)
+{
+	uint32_t num;
+	uint32_t dsc_per_block =
+	    ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s);
+
+	num = ext4_sb_is_super_in_bg(s, block_group);
+
+	if (!ext4_sb_feature_incom(s, EXT4_FINCOM_META_BG) ||
+	    block_group < ext4_sb_first_meta_bg(s) * dsc_per_block) {
+		if (num) {
+			num += ext4_bg_num_gdb(s, block_group);
+			num += ext4_get16(s, s_reserved_gdt_blocks);
+		}
+	} else {
+		num += ext4_bg_num_gdb(s, block_group);
+	}
+
+	uint32_t clustersize = 1024 << ext4_get32(s, log_cluster_size);
+	uint32_t cluster_ratio = clustersize / ext4_sb_get_block_size(s);
+	uint32_t v =
+	    (num + cluster_ratio - 1) >> ext4_get32(s, log_cluster_size);
+
+	return v;
+}
+
+/**
+ * @}
+ */