#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 */