#ifndef _LINUX_EXT4_EXT
#define _LINUX_EXT4_EXT
/*
* This is the extent tail on-disk structure.
* All other extent structures are 12 bytes long. It turns out that
* block_size % 12 >= 4 for at least all powers of 2 greater than 512, which
* covers all valid ext4 block sizes. Therefore, this tail structure can be
* crammed into the end of the block without having to rebalance the tree.
*/
struct ext4_extent_tail {
uint32_t et_checksum; /* crc32c(uuid+inum+extent_block) */
};
/*
* This is the extent on-disk structure.
* It's used at the bottom of the tree.
*/
typedef struct ext4_extent {
uint32_t ee_block; /* first logical block extent covers */
uint16_t ee_len; /* number of blocks covered by extent */
uint16_t ee_start_hi; /* high 16 bits of physical block */
uint32_t ee_start_lo; /* low 32 bits of physical block */
} __attribute__ ((__packed__)) EXT4_EXTENT;
/*
* This is index on-disk structure.
* It's used at all the levels except the bottom.
*/
typedef struct ext4_extent_idx {
uint32_t ei_block; /* index covers logical blocks from 'block' */
uint32_t ei_leaf_lo; /* pointer to the physical block of the next *
* level. leaf or next index could be there */
uint16_t ei_leaf_hi; /* high 16 bits of physical block */
uint16_t ei_unused;
}__attribute__ ((__packed__)) EXT4_EXTENT_IDX;
/*
* Each block (leaves and indexes), even inode-stored has header.
*/
typedef struct ext4_extent_header {
uint16_t eh_magic; /* probably will support different formats */
uint16_t eh_entries; /* number of valid entries */
uint16_t eh_max; /* capacity of store in entries */
uint16_t eh_depth; /* has tree real underlying blocks? */
uint32_t eh_generation; /* generation of the tree */
}__attribute__ ((__packed__)) EXT4_EXTENT_HEADER;
#define EXT4_EXT_MAGIC 0xf30a
#define get_ext4_header(i) ((struct ext4_extent_header *) (i)->i_block)
#define EXT4_EXTENT_TAIL_OFFSET(hdr) \
(sizeof(struct ext4_extent_header) + \
(sizeof(struct ext4_extent) * (hdr)->eh_max))
static inline struct ext4_extent_tail *
find_ext4_extent_tail(struct ext4_extent_header *eh)
{
return (struct ext4_extent_tail *)(((char *)eh) +
EXT4_EXTENT_TAIL_OFFSET(eh));
}
/*
* Array of ext4_ext_path contains path to some extent.
* Creation/lookup routines use it for traversal/splitting/etc.
* Truncate uses it to simulate recursive walking.
*/
struct ext4_ext_path
{
ext4_fsblk_t p_block;
int p_depth;
int p_maxdepth;
struct ext4_extent *p_ext;
struct ext4_extent_idx *p_idx;
struct ext4_extent_header *p_hdr;
struct buffer_head *p_bh;
};
/*
* structure for external API
*/
/*
* EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an
* initialized extent. This is 2^15 and not (2^16 - 1), since we use the
* MSB of ee_len field in the extent datastructure to signify if this
* particular extent is an initialized extent or an uninitialized (i.e.
* preallocated).
* EXT_UNINIT_MAX_LEN is the maximum number of blocks we can have in an
* uninitialized extent.
* If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an
* uninitialized one. In other words, if MSB of ee_len is set, it is an
* uninitialized extent with only one special scenario when ee_len = 0x8000.
* In this case we can not have an uninitialized extent of zero length and
* thus we make it as a special case of initialized extent with 0x8000 length.
* This way we get better extent-to-group alignment for initialized extents.
* Hence, the maximum number of blocks we can have in an *initialized*
* extent is 2^15 (32768) and in an *uninitialized* extent is 2^15-1 (32767).
*/
#define EXT_INIT_MAX_LEN (1UL << 15)
#define EXT_UNWRITTEN_MAX_LEN (EXT_INIT_MAX_LEN - 1)
#define EXT_EXTENT_SIZE sizeof(struct ext4_extent)
#define EXT_INDEX_SIZE sizeof(struct ext4_extent_idx)
#define EXT_FIRST_EXTENT(__hdr__) \
((struct ext4_extent *)(((char *)(__hdr__)) + \
sizeof(struct ext4_extent_header)))
#define EXT_FIRST_INDEX(__hdr__) \
((struct ext4_extent_idx *)(((char *)(__hdr__)) + \
sizeof(struct ext4_extent_header)))
#define EXT_HAS_FREE_INDEX(__path__) \
((__path__)->p_hdr->eh_entries < (__path__)->p_hdr->eh_max)
#define EXT_LAST_EXTENT(__hdr__) \
(EXT_FIRST_EXTENT((__hdr__)) + (__hdr__)->eh_entries - 1)
#define EXT_LAST_INDEX(__hdr__) \
(EXT_FIRST_INDEX((__hdr__)) + (__hdr__)->eh_entries - 1)
#define EXT_MAX_EXTENT(__hdr__) \
(EXT_FIRST_EXTENT((__hdr__)) + (__hdr__)->eh_max - 1)
#define EXT_MAX_INDEX(__hdr__) \
(EXT_FIRST_INDEX((__hdr__)) + (__hdr__)->eh_max - 1)
static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode)
{
return get_ext4_header(inode);
}
static inline struct ext4_extent_header *ext_block_hdr(struct buffer_head *bh)
{
return (struct ext4_extent_header *)bh->b_data;
}
static inline unsigned short ext_depth(struct inode *inode)
{
return ext_inode_hdr(inode)->eh_depth;
}
static inline void ext4_ext_mark_uninitialized(struct ext4_extent *ext)
{
/* We can not have an uninitialized extent of zero length! */
ext->ee_len |= EXT_INIT_MAX_LEN;
}
static inline int ext4_ext_is_uninitialized(struct ext4_extent *ext)
{
/* Extent with ee_len of 0x8000 is treated as an initialized extent */
return (ext->ee_len > EXT_INIT_MAX_LEN);
}
static inline uint16_t ext4_ext_get_actual_len(struct ext4_extent *ext)
{
return (ext->ee_len <= EXT_INIT_MAX_LEN
? ext->ee_len
: (ext->ee_len - EXT_INIT_MAX_LEN));
}
static inline void ext4_ext_mark_initialized(struct ext4_extent *ext)
{
ext->ee_len = ext4_ext_get_actual_len(ext);
}
static inline void ext4_ext_mark_unwritten(struct ext4_extent *ext)
{
/* We can not have an unwritten extent of zero length! */
ext->ee_len |= EXT_INIT_MAX_LEN;
}
static inline int ext4_ext_is_unwritten(struct ext4_extent *ext)
{
/* Extent with ee_len of 0x8000 is treated as an initialized extent */
return (ext->ee_len > EXT_INIT_MAX_LEN);
}
/*
* ext4_ext_pblock:
* combine low and high parts of physical block number into ext4_fsblk_t
*/
static inline ext4_fsblk_t ext4_ext_pblock(struct ext4_extent *ex)
{
ext4_fsblk_t block;
block = ex->ee_start_lo;
block |= ((ext4_fsblk_t)ex->ee_start_hi << 31) << 1;
return block;
}
/*
* ext4_idx_pblock:
* combine low and high parts of a leaf physical block number into ext4_fsblk_t
*/
static inline ext4_fsblk_t ext4_idx_pblock(struct ext4_extent_idx *ix)
{
ext4_fsblk_t block;
block = ix->ei_leaf_lo;
block |= ((ext4_fsblk_t)ix->ei_leaf_hi << 31) << 1;
return block;
}
/*
* ext4_ext_store_pblock:
* stores a large physical block number into an extent struct,
* breaking it into parts
*/
static inline void ext4_ext_store_pblock(struct ext4_extent *ex,
ext4_fsblk_t pb)
{
ex->ee_start_lo = (uint32_t)(pb & 0xffffffff);
ex->ee_start_hi = (uint16_t)((pb >> 31) >> 1) & 0xffff;
}
/*
* ext4_idx_store_pblock:
* stores a large physical block number into an index struct,
* breaking it into parts
*/
static inline void ext4_idx_store_pblock(struct ext4_extent_idx *ix,
ext4_fsblk_t pb)
{
ix->ei_leaf_lo = (uint32_t)(pb & 0xffffffff);
ix->ei_leaf_hi = (uint16_t)((pb >> 31) >> 1) & 0xffff;
}
#define ext4_ext_dirty(icb, handle, inode, path) \
__ext4_ext_dirty("", __LINE__, (icb), (handle), (inode), (path))
#define INODE_HAS_EXTENT(i) ((i)->i_flags & EXT2_EXTENTS_FL)
static inline uint64_t ext_to_block(EXT4_EXTENT *extent)
{
uint64_t block;
block = (uint64_t)extent->ee_start_lo;
block |= ((uint64_t) extent->ee_start_hi << 31) << 1;
return block;
}
static inline uint64_t idx_to_block(EXT4_EXTENT_IDX *idx)
{
uint64_t block;
block = (uint64_t)idx->ei_leaf_lo;
block |= ((uint64_t) idx->ei_leaf_hi << 31) << 1;
return block;
}
int ext4_ext_get_blocks(void *icb, handle_t *handle, struct inode *inode, ext4_fsblk_t iblock,
unsigned long max_blocks, struct buffer_head *bh_result,
int create, int flags);
int ext4_ext_tree_init(void *icb, handle_t *handle, struct inode *inode);
int ext4_ext_truncate(void *icb, struct inode *inode, unsigned long start);
#endif /* _LINUX_EXT4_EXT */