[1699] 2008-07-13 Bean <address@hidden>

[Bean]

Revision: 1699
          http://svn.sv.gnu.org/viewvc/?view=rev&root=grub&revision=1699
Author:   bean
Date:     2008-07-13 01:13:12 +0000 (Sun, 13 Jul 2008)

Log Message:
-----------
2008-07-13  Bean  <address@hidden>

        * fs/ext2.c (EXT4_EXTENTS_FLAG): New macro.
        (grub_ext4_extent_header): New structure.
        (grub_ext4_extent): Likewise.
        (grub_ext4_extent_idx): Likewise.
        (grub_ext4_find_leaf): New function.
        (grub_ext2_read_block): Handle extents.

Modified Paths:
--------------
    trunk/grub2/ChangeLog
    trunk/grub2/fs/ext2.c

Modified: trunk/grub2/ChangeLog
===================================================================
--- trunk/grub2/ChangeLog       2008-07-12 15:40:50 UTC (rev 1698)
+++ trunk/grub2/ChangeLog       2008-07-13 01:13:12 UTC (rev 1699)
@@ -1,3 +1,12 @@
+2008-07-13  Bean  <address@hidden>
+
+       * fs/ext2.c (EXT4_EXTENTS_FLAG): New macro.
+       (grub_ext4_extent_header): New structure.
+       (grub_ext4_extent): Likewise.
+       (grub_ext4_extent_idx): Likewise.
+       (grub_ext4_find_leaf): New function.
+       (grub_ext2_read_block): Handle extents.
+
 2008-07-12  Robert Millan  <address@hidden>
 
        * util/i386/pc/grub-mkrescue.in: s/grub-install/grub-mkrescue/g.

Modified: trunk/grub2/fs/ext2.c
===================================================================
--- trunk/grub2/fs/ext2.c       2008-07-12 15:40:50 UTC (rev 1698)
+++ trunk/grub2/fs/ext2.c       2008-07-13 01:13:12 UTC (rev 1699)
@@ -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 @@
   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;
@@ -262,7 +291,46 @@
                         sizeof (struct grub_ext2_block_group), (char *) 
blkgrp);
 }
 
+static struct grub_ext4_extent_header *
+grub_ext4_find_leaf (struct grub_ext2_data *data, char *buf,
+                     struct grub_ext4_extent_header *ext_block,
+                     grub_uint32_t fileblock)
+{
+  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, EXT2_BLOCK_SIZE(data), 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 +340,50 @@
   unsigned int blksz = EXT2_BLOCK_SIZE (data);
   int log2_blksz = LOG2_EXT2_BLOCK_SIZE (data);
   
+  if (inode->flags & EXT4_EXTENTS_FLAG)
+    {
+      char buf[EXT2_BLOCK_SIZE(data)];
+      struct grub_ext4_extent_header *leaf;
+      struct grub_ext4_extent *ext;
+      int i;
+
+      leaf = grub_ext4_find_leaf (data, buf,
+                                  (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))
+            break;
+        }
+
+      if (--i >= 0)
+        {
+          fileblock -= grub_le_to_cpu32 (ext[i].block);
+          if (fileblock >= grub_le_to_cpu16 (ext[i].len))
+            return 0;
+          else
+            {
+              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 + start;
+            }
+        }
+      else
+        {
+          grub_error (GRUB_ERR_BAD_FS, "something wrong with extent");
+          return -1;
+        }
+    }
   /* Direct blocks.  */
   if (fileblock < INDIRECT_BLOCKS)
     blknr = grub_le_to_cpu32 (inode->blocks.dir_blocks[fileblock]);