add ext4 support

SVN-Revision: 24079

package/grub/patches/020-ext4_support.patch

@@ -0,0 +1,267 @@
+--- a/stage2/fsys_ext2fs.c
++++ b/stage2/fsys_ext2fs.c
+@@ -51,6 +51,9 @@ typedef unsigned int __u32;
+ #define EXT2_TIND_BLOCK                 (EXT2_DIND_BLOCK + 1)
+ #define EXT2_N_BLOCKS                   (EXT2_TIND_BLOCK + 1)
+ 
++/* Inode flags */
++#define EXT4_EXTENTS_FL                 0x00080000 /* Inode uses extents */
++
+ /* include/linux/ext2_fs.h */
+ struct ext2_super_block
+   {
+@@ -191,6 +194,42 @@ struct ext2_dir_entry
+ #define EXT2_DIR_REC_LEN(name_len)      (((name_len) + 8 + EXT2_DIR_ROUND) & \
+                                          ~EXT2_DIR_ROUND)
+ 
++/* linux/ext4_fs_extents.h */
++/*
++ * This is the extent on-disk structure.
++ * It's used at the bottom of the tree.
++ */
++struct ext4_extent {
++    __u32 ee_block;       /* first logical block extent covers */
++    __u16 ee_len;         /* number of blocks covered by extent */
++    __u16 ee_start_hi;    /* high 16 bits of physical block */
++    __u32 ee_start;       /* low 32 bits of physical block */
++};
++
++/*
++ * This is index on-disk structure.
++ * It's used at all the levels except the bottom.
++ */
++struct ext4_extent_idx {
++    __u32 ei_block;       /* index covers logical blocks from 'block' */
++    __u32 ei_leaf;        /* pointer to the physical block of the next *
++                                 * level. leaf or next index could be there */
++    __u16 ei_leaf_hi;     /* high 16 bits of physical block */
++    __u16 ei_unused;
++};
++
++/*
++ * Each block (leaves and indexes), even inode-stored has header.
++ */
++struct ext4_extent_header {
++    __u16  eh_magic;       /* probably will support different formats */
++    __u16  eh_entries;     /* number of valid entries */
++    __u16  eh_max;         /* capacity of store in entries */
++    __u16  eh_depth;       /* has tree real underlying blocks? */
++    __u32  eh_generation;  /* generation of the tree */
++};
++
++#define EXT4_EXT_MAGIC          0xf30a
+ 
+ /* ext2/super.c */
+ #define log2(n) ffz(~(n))
+@@ -279,6 +318,27 @@ ext2_rdfsb (int fsblock, int buffer)
+ 		  EXT2_BLOCK_SIZE (SUPERBLOCK), (char *) buffer);
+ }
+ 
++/* Walk through extents index tree to find the good leaf */
++static struct ext4_extent_header *
++ext4_recurse_extent_index(struct ext4_extent_header *extent_block, int logical_block)
++{
++  int i;
++  struct ext4_extent_idx *index = (struct ext4_extent_idx *) (extent_block + 1);
++  if (extent_block->eh_magic != EXT4_EXT_MAGIC)
++    return NULL;
++  if (extent_block->eh_depth == 0)
++    return extent_block;
++  for (i = 0; i < extent_block->eh_entries; i++)
++    {
++      if (logical_block < index[i].ei_block)
++        break;
++    }
++  if (i == 0 || !ext2_rdfsb(index[i-1].ei_leaf, DATABLOCK1))
++    return NULL;
++  return (ext4_recurse_extent_index((struct ext4_extent_header *) DATABLOCK1, logical_block));
++}
++
++
+ /* from
+   ext2/inode.c:ext2_bmap()
+ */
+@@ -287,7 +347,6 @@ ext2_rdfsb (int fsblock, int buffer)
+ static int
+ ext2fs_block_map (int logical_block)
+ {
+-
+ #ifdef E2DEBUG
+   unsigned char *i;
+   for (i = (unsigned char *) INODE;
+@@ -308,82 +367,106 @@ ext2fs_block_map (int logical_block)
+   printf ("logical block %d\n", logical_block);
+ #endif /* E2DEBUG */
+ 
+-  /* if it is directly pointed to by the inode, return that physical addr */
+-  if (logical_block < EXT2_NDIR_BLOCKS)
++  if (!(INODE->i_flags & EXT4_EXTENTS_FL))
+     {
+-#ifdef E2DEBUG
+-      printf ("returning %d\n", (unsigned char *) (INODE->i_block[logical_block]));
+-      printf ("returning %d\n", INODE->i_block[logical_block]);
+-#endif /* E2DEBUG */
+-      return INODE->i_block[logical_block];
+-    }
+-  /* else */
+-  logical_block -= EXT2_NDIR_BLOCKS;
+-  /* try the indirect block */
+-  if (logical_block < EXT2_ADDR_PER_BLOCK (SUPERBLOCK))
+-    {
+-      if (mapblock1 != 1
+-	  && !ext2_rdfsb (INODE->i_block[EXT2_IND_BLOCK], DATABLOCK1))
+-	{
+-	  errnum = ERR_FSYS_CORRUPT;
+-	  return -1;
+-	}
+-      mapblock1 = 1;
+-      return ((__u32 *) DATABLOCK1)[logical_block];
+-    }
+-  /* else */
+-  logical_block -= EXT2_ADDR_PER_BLOCK (SUPERBLOCK);
+-  /* now try the double indirect block */
+-  if (logical_block < (1 << (EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK) * 2)))
+-    {
+-      int bnum;
+-      if (mapblock1 != 2
+-	  && !ext2_rdfsb (INODE->i_block[EXT2_DIND_BLOCK], DATABLOCK1))
+-	{
+-	  errnum = ERR_FSYS_CORRUPT;
+-	  return -1;
+-	}
+-      mapblock1 = 2;
+-      if ((bnum = (((__u32 *) DATABLOCK1)
+-		   [logical_block >> EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK)]))
+-	  != mapblock2
+-	  && !ext2_rdfsb (bnum, DATABLOCK2))
+-	{
+-	  errnum = ERR_FSYS_CORRUPT;
+-	  return -1;
+-	}
+-      mapblock2 = bnum;
++      /* if it is directly pointed to by the inode, return that physical addr */
++      if (logical_block < EXT2_NDIR_BLOCKS)
++        {
++#ifdef E2DEBUG
++          printf ("returning %d\n", (unsigned char *) (INODE->i_block[logical_block]));
++          printf ("returning %d\n", INODE->i_block[logical_block]);
++#endif /* E2DEBUG */
++          return INODE->i_block[logical_block];
++        }
++      /* else */
++      logical_block -= EXT2_NDIR_BLOCKS;
++      /* try the indirect block */
++      if (logical_block < EXT2_ADDR_PER_BLOCK (SUPERBLOCK))
++        {
++          if (mapblock1 != 1 && !ext2_rdfsb (INODE->i_block[EXT2_IND_BLOCK], DATABLOCK1))
++            {
++              errnum = ERR_FSYS_CORRUPT;
++              return -1;
++            }
++          mapblock1 = 1;
++          return ((__u32 *) DATABLOCK1)[logical_block];
++        }
++      /* else */
++      logical_block -= EXT2_ADDR_PER_BLOCK (SUPERBLOCK);
++      /* now try the double indirect block */
++      if (logical_block < (1 << (EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK) * 2)))
++        {
++          int bnum;
++          if (mapblock1 != 2 && !ext2_rdfsb (INODE->i_block[EXT2_DIND_BLOCK], DATABLOCK1))
++            {
++              errnum = ERR_FSYS_CORRUPT;
++              return -1;
++            }
++          mapblock1 = 2;
++          if ((bnum = (((__u32 *) DATABLOCK1)
++                  [logical_block >> EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK)]))
++         != mapblock2
++         && !ext2_rdfsb (bnum, DATABLOCK2))
++           {
++             errnum = ERR_FSYS_CORRUPT;
++             return -1;
++           }
++          mapblock2 = bnum;
++          return ((__u32 *) DATABLOCK2)
++            [logical_block & (EXT2_ADDR_PER_BLOCK (SUPERBLOCK) - 1)];
++        }
++      /* else */
++      mapblock2 = -1;
++      logical_block -= (1 << (EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK) * 2));
++      if (mapblock1 != 3
++          && !ext2_rdfsb (INODE->i_block[EXT2_TIND_BLOCK], DATABLOCK1))
++        {
++          errnum = ERR_FSYS_CORRUPT;
++          return -1;
++        }
++      mapblock1 = 3;
++      if (!ext2_rdfsb (((__u32 *) DATABLOCK1)
++                  [logical_block >> (EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK)
++                                     * 2)],
++                  DATABLOCK2))
++        {
++          errnum = ERR_FSYS_CORRUPT;
++          return -1;
++        }
++      if (!ext2_rdfsb (((__u32 *) DATABLOCK2)
++                  [(logical_block >> EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK))
++                   & (EXT2_ADDR_PER_BLOCK (SUPERBLOCK) - 1)],
++                  DATABLOCK2))
++        {
++          errnum = ERR_FSYS_CORRUPT;
++          return -1;
++        }
++
+       return ((__u32 *) DATABLOCK2)
+-	[logical_block & (EXT2_ADDR_PER_BLOCK (SUPERBLOCK) - 1)];
++       [logical_block & (EXT2_ADDR_PER_BLOCK (SUPERBLOCK) - 1)];
+     }
+-  /* else */
+-  mapblock2 = -1;
+-  logical_block -= (1 << (EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK) * 2));
+-  if (mapblock1 != 3
+-      && !ext2_rdfsb (INODE->i_block[EXT2_TIND_BLOCK], DATABLOCK1))
+-    {
+-      errnum = ERR_FSYS_CORRUPT;
+-      return -1;
+-    }
+-  mapblock1 = 3;
+-  if (!ext2_rdfsb (((__u32 *) DATABLOCK1)
+-		   [logical_block >> (EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK)
+-				      * 2)],
+-		   DATABLOCK2))
+-    {
+-      errnum = ERR_FSYS_CORRUPT;
+-      return -1;
+-    }
+-  if (!ext2_rdfsb (((__u32 *) DATABLOCK2)
+-		   [(logical_block >> EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK))
+-		    & (EXT2_ADDR_PER_BLOCK (SUPERBLOCK) - 1)],
+-		   DATABLOCK2))
++    /* inode is in extents format */
++    else
+     {
++      int i;
++      struct ext4_extent_header *extent_hdr =
++         ext4_recurse_extent_index((struct ext4_extent_header *) INODE->i_block, logical_block);
++      struct ext4_extent *extent = (struct ext4_extent *) (extent_hdr + 1);
++      if ( extent_hdr == NULL || extent_hdr->eh_magic != EXT4_EXT_MAGIC)
++        {
++          errnum = ERR_FSYS_CORRUPT;
++          return -1;
++        }
++      for (i = 0; i<extent_hdr->eh_entries; i++)
++        {
++          if (extent[i].ee_block <= logical_block && logical_block < extent[i].ee_block + extent[i].ee_len && !(extent[i].ee_len>>15))
++            return (logical_block - extent[i].ee_block + extent[i].ee_start);
++        }
++      /* We should not arrive here */
++
+       errnum = ERR_FSYS_CORRUPT;
+       return -1;
+     }
+-  return ((__u32 *) DATABLOCK2)
+-    [logical_block & (EXT2_ADDR_PER_BLOCK (SUPERBLOCK) - 1)];
+ }
+ 
+ /* preconditions: all preconds of ext2fs_block_map */