fs/ext4: Support device block sizes != 512 bytes

The 512 byte block size was hard coded in the ext4 file systems.
Large harddisks today support bigger block sizes typically 4096
bytes.
This patch removes this limitation.

Signed-off-by: Egbert Eich <eich@suse.com>
diff --git a/fs/ext4/ext4_common.c b/fs/ext4/ext4_common.c
index f12b805..58880b4 100644
--- a/fs/ext4/ext4_common.c
+++ b/fs/ext4/ext4_common.c
@@ -71,18 +71,18 @@
 	uint64_t startblock;
 	uint64_t remainder;
 	unsigned char *temp_ptr = NULL;
-	ALLOC_CACHE_ALIGN_BUFFER(unsigned char, sec_buf, SECTOR_SIZE);
 	struct ext_filesystem *fs = get_fs();
+	int log2blksz = fs->dev_desc->log2blksz;
+	ALLOC_CACHE_ALIGN_BUFFER(unsigned char, sec_buf, fs->dev_desc->blksz);
 
-	startblock = off / (uint64_t)SECTOR_SIZE;
+	startblock = off >> log2blksz;
 	startblock += part_offset;
-	remainder = off % (uint64_t)SECTOR_SIZE;
-	remainder &= SECTOR_SIZE - 1;
+	remainder = off & (uint64_t)(fs->dev_desc->blksz - 1);
 
 	if (fs->dev_desc == NULL)
 		return;
 
-	if ((startblock + (size / SECTOR_SIZE)) >
+	if ((startblock + (size >> log2blksz)) >
 	    (part_offset + fs->total_sect)) {
 		printf("part_offset is %lu\n", part_offset);
 		printf("total_sector is %llu\n", fs->total_sect);
@@ -101,10 +101,10 @@
 						  startblock, 1, sec_buf);
 		}
 	} else {
-		if (size / SECTOR_SIZE != 0) {
+		if (size >> log2blksz != 0) {
 			fs->dev_desc->block_write(fs->dev_desc->dev,
 						  startblock,
-						  size / SECTOR_SIZE,
+						  size >> log2blksz,
 						  (unsigned long *)buf);
 		} else {
 			fs->dev_desc->block_read(fs->dev_desc->dev,
@@ -1459,6 +1459,7 @@
 {
 	long int blkno;
 	unsigned int blkoff, desc_per_blk;
+	int log2blksz = get_fs()->dev_desc->log2blksz;
 
 	desc_per_blk = EXT2_BLOCK_SIZE(data) / sizeof(struct ext2_block_group);
 
@@ -1469,7 +1470,7 @@
 	debug("ext4fs read %d group descriptor (blkno %ld blkoff %u)\n",
 	      group, blkno, blkoff);
 
-	return ext4fs_devread(blkno << LOG2_EXT2_BLOCK_SIZE(data),
+	return ext4fs_devread(blkno << (LOG2_BLOCK_SIZE(data) - log2blksz),
 			      blkoff, sizeof(struct ext2_block_group),
 			      (char *)blkgrp);
 }
@@ -1479,6 +1480,7 @@
 	struct ext2_block_group blkgrp;
 	struct ext2_sblock *sblock = &data->sblock;
 	struct ext_filesystem *fs = get_fs();
+	int log2blksz = get_fs()->dev_desc->log2blksz;
 	int inodes_per_block, status;
 	long int blkno;
 	unsigned int blkoff;
@@ -1495,7 +1497,8 @@
 	    (ino % __le32_to_cpu(sblock->inodes_per_group)) / inodes_per_block;
 	blkoff = (ino % inodes_per_block) * fs->inodesz;
 	/* Read the inode. */
-	status = ext4fs_devread(blkno << LOG2_EXT2_BLOCK_SIZE(data), blkoff,
+	status = ext4fs_devread(blkno << (LOG2_BLOCK_SIZE(data) - log2blksz),
+				blkoff,
 				sizeof(struct ext2_inode), (char *)inode);
 	if (status == 0)
 		return 0;
@@ -1515,7 +1518,9 @@
 	unsigned long long start;
 	/* get the blocksize of the filesystem */
 	blksz = EXT2_BLOCK_SIZE(ext4fs_root);
-	log2_blksz = LOG2_EXT2_BLOCK_SIZE(ext4fs_root);
+	log2_blksz = LOG2_BLOCK_SIZE(ext4fs_root)
+		- get_fs()->dev_desc->log2blksz;
+
 	if (le32_to_cpu(inode->flags) & EXT4_EXTENTS_FL) {
 		char *buf = zalloc(blksz);
 		if (!buf)
@@ -1523,11 +1528,11 @@
 		struct ext4_extent_header *ext_block;
 		struct ext4_extent *extent;
 		int i = -1;
-		ext_block = ext4fs_get_extent_block(ext4fs_root, buf,
-						    (struct ext4_extent_header
-						     *)inode->b.
-						    blocks.dir_blocks,
-						    fileblock, log2_blksz);
+		ext_block =
+			ext4fs_get_extent_block(ext4fs_root, buf,
+						(struct ext4_extent_header *)
+						inode->b.blocks.dir_blocks,
+						fileblock, log2_blksz);
 		if (!ext_block) {
 			printf("invalid extent block\n");
 			free(buf);
@@ -1839,7 +1844,7 @@
 		blknr = __le32_to_cpu(ext4fs_indir3_block
 				      [rblock % perblock_child]);
 	}
-	debug("ext4fs_read_block %ld\n", blknr);
+	debug("read_allocated_block %ld\n", blknr);
 
 	return blknr;
 }
@@ -2193,13 +2198,12 @@
 	struct ext2_data *data;
 	int status;
 	struct ext_filesystem *fs = get_fs();
-	data = zalloc(sizeof(struct ext2_data));
+	data = zalloc(SUPERBLOCK_SIZE);
 	if (!data)
 		return 0;
 
 	/* Read the superblock. */
-	status = ext4fs_devread(1 * 2, 0, sizeof(struct ext2_sblock),
-				(char *)&data->sblock);
+	status = ext4_read_superblock((char *)&data->sblock);
 
 	if (status == 0)
 		goto fail;