# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1261393001 0
# Node ID aa61264ed7d97f1478008992954a6ab008aa8977
# Parent b24854b13e16e8acbb51403e3ac762b382960c6d
pygrub: add ext4 support
This is a port of the following two patches:
http://patches.ubuntulinux.org/g/grub/extracted/ext4_support.diff
http://patches.ubuntulinux.org/g/grub/extracted/ext4_fix_variable_sized_inodes.diff
Signed-off-by: Mark Johnson <mark.johnson@xxxxxxx>
xen-unstable changeset: 20652:c6ee21dca848
xen-unstable date: Wed Dec 16 16:42:44 2009 +0000
---
tools/libfsimage/ext2fs/fsys_ext2fs.c | 237 +++++++++++++++++++++++-----------
1 files changed, 161 insertions(+), 76 deletions(-)
diff -r b24854b13e16 -r aa61264ed7d9 tools/libfsimage/ext2fs/fsys_ext2fs.c
--- a/tools/libfsimage/ext2fs/fsys_ext2fs.c Wed Dec 16 13:57:10 2009 +0000
+++ b/tools/libfsimage/ext2fs/fsys_ext2fs.c Mon Dec 21 10:56:41 2009 +0000
@@ -48,6 +48,9 @@ typedef unsigned int __u32;
#define EXT2_DIND_BLOCK (EXT2_IND_BLOCK + 1)
#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
@@ -234,6 +237,42 @@ 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) grub_log2(n)
@@ -311,6 +350,27 @@ ext2_rdfsb (fsi_file_t *ffi, int fsblock
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(fsi_file_t *ffi, 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(ffi, index[i-1].ei_leaf, DATABLOCK1))
+ return NULL;
+ return (ext4_recurse_extent_index(ffi, (struct ext4_extent_header *)
DATABLOCK1, logical_block));
+}
+
+
/* from
ext2/inode.c:ext2_bmap()
*/
@@ -319,7 +379,6 @@ static int
static int
ext2fs_block_map (fsi_file_t *ffi, int logical_block)
{
-
#ifdef E2DEBUG
unsigned char *i;
for (i = (unsigned char *) INODE;
@@ -340,82 +399,106 @@ ext2fs_block_map (fsi_file_t *ffi, int l
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))
+ {
+ /* 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 (ffi,
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 (ffi,
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 (ffi, 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 (ffi, INODE->i_block[EXT2_TIND_BLOCK], DATABLOCK1))
+ {
+ errnum = ERR_FSYS_CORRUPT;
+ return -1;
+ }
+ mapblock1 = 3;
+ if (!ext2_rdfsb (ffi, ((__u32 *) DATABLOCK1)
+ [logical_block >> (EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK)
+ * 2)],
+ DATABLOCK2))
+ {
+ errnum = ERR_FSYS_CORRUPT;
+ return -1;
+ }
+ if (!ext2_rdfsb (ffi, ((__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)];
+ }
+ /* inode is in extents format */
+ else
{
-#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 (ffi, 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 (ffi, 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 (ffi, 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 (ffi, INODE->i_block[EXT2_TIND_BLOCK], DATABLOCK1))
- {
+ int i;
+ struct ext4_extent_header *extent_hdr =
+ ext4_recurse_extent_index(ffi, (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;
}
- mapblock1 = 3;
- if (!ext2_rdfsb (ffi, ((__u32 *) DATABLOCK1)
- [logical_block >> (EXT2_ADDR_PER_BLOCK_BITS (SUPERBLOCK)
- * 2)],
- DATABLOCK2))
- {
- errnum = ERR_FSYS_CORRUPT;
- return -1;
- }
- if (!ext2_rdfsb (ffi, ((__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)];
}
/* preconditions: all preconds of ext2fs_block_map */
@@ -548,6 +631,8 @@ ext2fs_dir (fsi_file_t *ffi, char *dirna
int off; /* offset within block of directory entry (off
mod blocksize) */
int loc; /* location within a directory */
int blk; /* which data blk within dir entry (off div
blocksize) */
+ int inodes_per_block; /* number of inodes in each block */
+ int inode_offset; /* inode offset in block */
long map; /* fs pointer of a particular block from dir
entry */
struct ext2_dir_entry *dp; /* pointer to directory entry */
#ifdef E2DEBUG
@@ -583,9 +668,9 @@ ext2fs_dir (fsi_file_t *ffi, char *dirna
return 0;
}
gdp = GROUP_DESC;
- ino_blk = gdp[desc].bg_inode_table +
- (((current_ino - 1) % (SUPERBLOCK->s_inodes_per_group))
- >> log2 (EXT2_INODES_PER_BLOCK (SUPERBLOCK)));
+ inodes_per_block = EXT2_BLOCK_SIZE (SUPERBLOCK) /
EXT2_INODE_SIZE(SUPERBLOCK);
+ inode_offset = ((current_ino - 1) % (SUPERBLOCK->s_inodes_per_group));
+ ino_blk = gdp[desc].bg_inode_table + (inode_offset / inodes_per_block);
#ifdef E2DEBUG
printf ("inode table fsblock=%d\n", ino_blk);
#endif /* E2DEBUG */
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