--- /dev/null
+--- 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 */
projects / openwrt / staging / jow.git / commitdiff