package/grub/patches/020-ext4_support.patch

   1 --- a/stage2/fsys_ext2fs.c
   2 +++ b/stage2/fsys_ext2fs.c
   3 @@ -51,6 +51,9 @@ typedef unsigned int __u32;
   4  #define EXT2_TIND_BLOCK                 (EXT2_DIND_BLOCK + 1)
   5  #define EXT2_N_BLOCKS                   (EXT2_TIND_BLOCK + 1)
   6
   7 +/* Inode flags */
   8 +#define EXT4_EXTENTS_FL                 0x00080000 /* Inode uses extents */
   9 +
  10  /* include/linux/ext2_fs.h */
  11  struct ext2_super_block
  12    {
  13 @@ -191,6 +194,42 @@ struct ext2_dir_entry
  14  #define EXT2_DIR_REC_LEN(name_len)      (((name_len) + 8 + EXT2_DIR_ROUND) & \
  15                                           ~EXT2_DIR_ROUND)
  16
  17 +/* linux/ext4_fs_extents.h */
  18 +/*
  19 + * This is the extent on-disk structure.
  20 + * It's used at the bottom of the tree.
  21 + */
  22 +struct ext4_extent {
  23 +    __u32 ee_block;       /* first logical block extent covers */
  24 +    __u16 ee_len;         /* number of blocks covered by extent */
  25 +    __u16 ee_start_hi;    /* high 16 bits of physical block */
  26 +    __u32 ee_start;       /* low 32 bits of physical block */
  27 +};
  28 +
  29 +/*
  30 + * This is index on-disk structure.
  31 + * It's used at all the levels except the bottom.
  32 + */
  33 +struct ext4_extent_idx {
  34 +    __u32 ei_block;       /* index covers logical blocks from 'block' */
  35 +    __u32 ei_leaf;        /* pointer to the physical block of the next *
  36 +                                 * level. leaf or next index could be there */
  37 +    __u16 ei_leaf_hi;     /* high 16 bits of physical block */
  38 +    __u16 ei_unused;
  39 +};
  40 +
  41 +/*
  42 + * Each block (leaves and indexes), even inode-stored has header.
  43 + */
  44 +struct ext4_extent_header {
  45 +    __u16  eh_magic;       /* probably will support different formats */
  46 +    __u16  eh_entries;     /* number of valid entries */
  47 +    __u16  eh_max;         /* capacity of store in entries */
  48 +    __u16  eh_depth;       /* has tree real underlying blocks? */
  49 +    __u32  eh_generation;  /* generation of the tree */
  50 +};
  51 +
  52 +#define EXT4_EXT_MAGIC          0xf30a
  53
  54  /* ext2/super.c */
  55  #define log2(n) ffz(~(n))
  56 @@ -279,6 +318,27 @@ ext2_rdfsb (int fsblock, int buffer)
  57                   EXT2_BLOCK_SIZE (SUPERBLOCK), (char *) buffer);
  58  }
  59
  60 +/* Walk through extents index tree to find the good leaf */
  61 +static struct ext4_extent_header *
  62 +ext4_recurse_extent_index(struct ext4_extent_header *extent_block, int logical_block)
  63 +{
  64 +  int i;
  65 +  struct ext4_extent_idx *index = (struct ext4_extent_idx *) (extent_block + 1);
  66 +  if (extent_block->eh_magic != EXT4_EXT_MAGIC)
  67 +    return NULL;
  68 +  if (extent_block->eh_depth == 0)
  69 +    return extent_block;
  70 +  for (i = 0; i < extent_block->eh_entries; i++)
  71 +    {
  72 +      if (logical_block < index[i].ei_block)
  73 +        break;
  74 +    }
  75 +  if (i == 0 || !ext2_rdfsb(index[i-1].ei_leaf, DATABLOCK1))
  76 +    return NULL;
  77 +  return (ext4_recurse_extent_index((struct ext4_extent_header *) DATABLOCK1, logical_block));
  78 +}
  79 +
  80 +
  81  /* from
  82    ext2/inode.c:ext2_bmap()
  83  */
  84 @@ -287,7 +347,6 @@ ext2_rdfsb (int fsblock, int buffer)
  85  static int
  86  ext2fs_block_map (int logical_block)
  87  {
  88 -
  89  #ifdef E2DEBUG
  90    unsigned char *i;
  91    for (i = (unsigned char *) INODE;
  92 @@ -308,82 +367,106 @@ ext2fs_block_map (int logical_block)
  93    printf ("logical block %d\n", logical_block);
  94  #endif /* E2DEBUG */
  95
  96 -  /* if it is directly pointed to by the inode, return that physical addr */
  97 -  if (logical_block < EXT2_NDIR_BLOCKS)
  98 +  if (!(INODE->i_flags & EXT4_EXTENTS_FL))
  99      {
 100 -#ifdef E2DEBUG
 101 -      printf ("returning %d\n", (unsigned char *) (INODE->i_block[logical_block]));
 102 -      printf ("returning %d\n", INODE->i_block[logical_block]);
 103 -#endif /* E2DEBUG */
 104 -      return INODE->i_block[logical_block];
 105 -    }
 106 -  /* else */
 107 -  logical_block -= EXT2_NDIR_BLOCKS;
 108 -  /* try the indirect block */
 109 -  if (logical_block < EXT2_ADDR_PER_BLOCK (SUPERBLOCK))
 110 -    {
 111 -      if (mapblock1 != 1
 112 -         && !ext2_rdfsb (INODE->i_block[EXT2_IND_BLOCK], DATABLOCK1))
 113 -       {
 114 -         errnum = ERR_FSYS_CORRUPT;
 115 -         return -1;
 116 -       }
 117 -      mapblock1 = 1;
 118 -      return ((__u32 *) DATABLOCK1)[logical_block];
 119 -    }
 120 -  /* else */
 121 -  logical_block -= EXT2_ADDR_PER_BLOCK (SUPERBLOCK);
 122 -  /* now try the double indirect block */
 123 -  if (logical_block < (1 << (EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK) * 2)))
 124 -    {
 125 -      int bnum;
 126 -      if (mapblock1 != 2
 127 -         && !ext2_rdfsb (INODE->i_block[EXT2_DIND_BLOCK], DATABLOCK1))
 128 -       {
 129 -         errnum = ERR_FSYS_CORRUPT;
 130 -         return -1;
 131 -       }
 132 -      mapblock1 = 2;
 133 -      if ((bnum = (((__u32 *) DATABLOCK1)
 134 -                  [logical_block >> EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK)]))
 135 -         != mapblock2
 136 -         && !ext2_rdfsb (bnum, DATABLOCK2))
 137 -       {
 138 -         errnum = ERR_FSYS_CORRUPT;
 139 -         return -1;
 140 -       }
 141 -      mapblock2 = bnum;
 142 +      /* if it is directly pointed to by the inode, return that physical addr */
 143 +      if (logical_block < EXT2_NDIR_BLOCKS)
 144 +        {
 145 +#ifdef E2DEBUG
 146 +          printf ("returning %d\n", (unsigned char *) (INODE->i_block[logical_block]));
 147 +          printf ("returning %d\n", INODE->i_block[logical_block]);
 148 +#endif /* E2DEBUG */
 149 +          return INODE->i_block[logical_block];
 150 +        }
 151 +      /* else */
 152 +      logical_block -= EXT2_NDIR_BLOCKS;
 153 +      /* try the indirect block */
 154 +      if (logical_block < EXT2_ADDR_PER_BLOCK (SUPERBLOCK))
 155 +        {
 156 +          if (mapblock1 != 1 && !ext2_rdfsb (INODE->i_block[EXT2_IND_BLOCK], DATABLOCK1))
 157 +            {
 158 +              errnum = ERR_FSYS_CORRUPT;
 159 +              return -1;
 160 +            }
 161 +          mapblock1 = 1;
 162 +          return ((__u32 *) DATABLOCK1)[logical_block];
 163 +        }
 164 +      /* else */
 165 +      logical_block -= EXT2_ADDR_PER_BLOCK (SUPERBLOCK);
 166 +      /* now try the double indirect block */
 167 +      if (logical_block < (1 << (EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK) * 2)))
 168 +        {
 169 +          int bnum;
 170 +          if (mapblock1 != 2 && !ext2_rdfsb (INODE->i_block[EXT2_DIND_BLOCK], DATABLOCK1))
 171 +            {
 172 +              errnum = ERR_FSYS_CORRUPT;
 173 +              return -1;
 174 +            }
 175 +          mapblock1 = 2;
 176 +          if ((bnum = (((__u32 *) DATABLOCK1)
 177 +                  [logical_block >> EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK)]))
 178 +         != mapblock2
 179 +         && !ext2_rdfsb (bnum, DATABLOCK2))
 180 +           {
 181 +             errnum = ERR_FSYS_CORRUPT;
 182 +             return -1;
 183 +           }
 184 +          mapblock2 = bnum;
 185 +          return ((__u32 *) DATABLOCK2)
 186 +            [logical_block & (EXT2_ADDR_PER_BLOCK (SUPERBLOCK) - 1)];
 187 +        }
 188 +      /* else */
 189 +      mapblock2 = -1;
 190 +      logical_block -= (1 << (EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK) * 2));
 191 +      if (mapblock1 != 3
 192 +          && !ext2_rdfsb (INODE->i_block[EXT2_TIND_BLOCK], DATABLOCK1))
 193 +        {
 194 +          errnum = ERR_FSYS_CORRUPT;
 195 +          return -1;
 196 +        }
 197 +      mapblock1 = 3;
 198 +      if (!ext2_rdfsb (((__u32 *) DATABLOCK1)
 199 +                  [logical_block >> (EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK)
 200 +                                     * 2)],
 201 +                  DATABLOCK2))
 202 +        {
 203 +          errnum = ERR_FSYS_CORRUPT;
 204 +          return -1;
 205 +        }
 206 +      if (!ext2_rdfsb (((__u32 *) DATABLOCK2)
 207 +                  [(logical_block >> EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK))
 208 +                   & (EXT2_ADDR_PER_BLOCK (SUPERBLOCK) - 1)],
 209 +                  DATABLOCK2))
 210 +        {
 211 +          errnum = ERR_FSYS_CORRUPT;
 212 +          return -1;
 213 +        }
 214 +
 215        return ((__u32 *) DATABLOCK2)
 216 -       [logical_block & (EXT2_ADDR_PER_BLOCK (SUPERBLOCK) - 1)];
 217 +       [logical_block & (EXT2_ADDR_PER_BLOCK (SUPERBLOCK) - 1)];
 218      }
 219 -  /* else */
 220 -  mapblock2 = -1;
 221 -  logical_block -= (1 << (EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK) * 2));
 222 -  if (mapblock1 != 3
 223 -      && !ext2_rdfsb (INODE->i_block[EXT2_TIND_BLOCK], DATABLOCK1))
 224 -    {
 225 -      errnum = ERR_FSYS_CORRUPT;
 226 -      return -1;
 227 -    }
 228 -  mapblock1 = 3;
 229 -  if (!ext2_rdfsb (((__u32 *) DATABLOCK1)
 230 -                  [logical_block >> (EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK)
 231 -                                     * 2)],
 232 -                  DATABLOCK2))
 233 -    {
 234 -      errnum = ERR_FSYS_CORRUPT;
 235 -      return -1;
 236 -    }
 237 -  if (!ext2_rdfsb (((__u32 *) DATABLOCK2)
 238 -                  [(logical_block >> EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK))
 239 -                   & (EXT2_ADDR_PER_BLOCK (SUPERBLOCK) - 1)],
 240 -                  DATABLOCK2))
 241 +    /* inode is in extents format */
 242 +    else
 243      {
 244 +      int i;
 245 +      struct ext4_extent_header *extent_hdr =
 246 +         ext4_recurse_extent_index((struct ext4_extent_header *) INODE->i_block, logical_block);
 247 +      struct ext4_extent *extent = (struct ext4_extent *) (extent_hdr + 1);
 248 +      if ( extent_hdr == NULL || extent_hdr->eh_magic != EXT4_EXT_MAGIC)
 249 +        {
 250 +          errnum = ERR_FSYS_CORRUPT;
 251 +          return -1;
 252 +        }
 253 +      for (i = 0; i<extent_hdr->eh_entries; i++)
 254 +        {
 255 +          if (extent[i].ee_block <= logical_block && logical_block < extent[i].ee_block + extent[i].ee_len && !(extent[i].ee_len>>15))
 256 +            return (logical_block - extent[i].ee_block + extent[i].ee_start);
 257 +        }
 258 +      /* We should not arrive here */
 259 +
 260        errnum = ERR_FSYS_CORRUPT;
 261        return -1;
 262      }
 263 -  return ((__u32 *) DATABLOCK2)
 264 -    [logical_block & (EXT2_ADDR_PER_BLOCK (SUPERBLOCK) - 1)];
 265  }
 266
 267  /* preconditions: all preconds of ext2fs_block_map */