Hi,
This patch add support for extents in ext4.
--
Bean
diff --git a/fs/ext2.c b/fs/ext2.c
index 22fd272..3518dcf 100644
--- a/fs/ext2.c
+++ b/fs/ext2.c
@@ -86,6 +86,8 @@
#define EXT3_JOURNAL_FLAG_DELETED 4
#define EXT3_JOURNAL_FLAG_LAST_TAG 8
+#define EXT4_EXTENTS_FLAG 0x80000
+
/* The ext2 superblock. */
struct grub_ext2_sblock
{
@@ -226,6 +228,33 @@ struct grub_ext3_journal_sblock
grub_uint32_t start;
};
+#define EXT4_EXT_MAGIC 0xf30a
+
+struct grub_ext4_extent_header
+{
+ grub_uint16_t magic;
+ grub_uint16_t entries;
+ grub_uint16_t max;
+ grub_uint16_t depth;
+ grub_uint32_t generation;
+};
+
+struct grub_ext4_extent
+{
+ grub_uint32_t block;
+ grub_uint16_t len;
+ grub_uint16_t start_hi;
+ grub_uint32_t start;
+};
+
+struct grub_ext4_extent_idx
+{
+ grub_uint32_t block;
+ grub_uint32_t leaf;
+ grub_uint16_t leaf_hi;
+ grub_uint16_t unused;
+};
+
struct grub_fshelp_node
{
struct grub_ext2_data *data;
@@ -262,6 +291,46 @@ grub_ext2_blockgroup (struct grub_ext2_data *data, int group,
sizeof (struct grub_ext2_block_group), (char *) blkgrp);
}
+static struct grub_ext4_extent_header *
+grub_ext4_find_leaf (struct grub_ext2_data *data,
+ struct grub_ext4_extent_header *ext_block,
+ grub_uint32_t fileblock)
+{
+ char buf[EXT2_BLOCK_SIZE(data)];
+ struct grub_ext4_extent_idx *index;
+
+ while (1)
+ {
+ int i;
+ grub_disk_addr_t block;
+
+ index = (struct grub_ext4_extent_idx *) (ext_block + 1);
+
+ if (grub_le_to_cpu16(ext_block->magic) != EXT4_EXT_MAGIC)
+ return 0;
+
+ if (ext_block->depth == 0)
+ return ext_block;
+
+ for (i = 0; i < grub_le_to_cpu16 (ext_block->entries); i++)
+ {
+ if (fileblock < grub_le_to_cpu32(index[i].block))
+ break;
+ }
+
+ if (i == 0)
+ return 0;
+
+ block = grub_le_to_cpu16 (index[i].leaf_hi);
+ block = (block << 32) + grub_le_to_cpu32 (index[i].leaf);
+ if (grub_disk_read (data->disk,
+ block << LOG2_EXT2_BLOCK_SIZE (data),
+ 0, sizeof (buf), buf))
+ return 0;
+
+ ext_block = (struct grub_ext4_extent_header *) buf;
+ }
+}
static grub_disk_addr_t
grub_ext2_read_block (grub_fshelp_node_t node, grub_disk_addr_t fileblock)
@@ -272,6 +341,41 @@ grub_ext2_read_block (grub_fshelp_node_t node, grub_disk_addr_t fileblock)
unsigned int blksz = EXT2_BLOCK_SIZE (data);
int log2_blksz = LOG2_EXT2_BLOCK_SIZE (data);
+ if (inode->flags & EXT4_EXTENTS_FLAG)
+ {
+ struct grub_ext4_extent_header *leaf;
+ struct grub_ext4_extent *ext;
+ int i;
+
+ leaf = grub_ext4_find_leaf (data,
+ (struct grub_ext4_extent_header *) inode->blocks.dir_blocks,
+ fileblock);
+ if (! leaf)
+ {
+ grub_error (GRUB_ERR_BAD_FS, "invalid extent");
+ return -1;
+ }
+
+ ext = (struct grub_ext4_extent *) (leaf + 1);
+ for (i = 0; i < grub_le_to_cpu16 (leaf->entries); i++)
+ if ((fileblock >= grub_le_to_cpu32 (ext[i].block)) &&
+ (fileblock < grub_le_to_cpu32 (ext[i].block) +
+ grub_le_to_cpu16 (ext[i].len)) &&
+ ((grub_le_to_cpu16 (ext[i].len) >> 15) == 0))
+ {
+ grub_disk_addr_t start;
+
+ start = grub_le_to_cpu16 (ext[i].start_hi);
+ start = (start << 32) + grub_le_to_cpu32 (ext[i].start);
+ return fileblock - grub_le_to_cpu32 (ext[i].block) + start;
+ }
+
+
+
+ grub_printf ("HH\n");
+ return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
+ "ext2fs doesn't support extents");
+ }
/* Direct blocks. */
if (fileblock < INDIRECT_BLOCKS)
blknr = grub_le_to_cpu32 (inode->blocks.dir_blocks[fileblock]);
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