/* * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com * Written by Alex Tomas * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public Licens * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111- */ #ifndef _LINUX_EXT4_EXTENTS #define _LINUX_EXT4_EXTENTS #include /* * with AGRESSIVE_TEST defined capacity of index/leaf blocks * become very little, so index split, in-depth growing and * other hard changes happens much more often * this is for debug purposes only */ #define AGRESSIVE_TEST_ /* * with EXTENTS_STATS defined number of blocks and extents * are collected in truncate path. they'll be showed at * umount time */ #define EXTENTS_STATS__ /* * if CHECK_BINSEARCH defined, then results of binary search * will be checked by linear search */ #define CHECK_BINSEARCH__ /* * if EXT_DEBUG is defined you can use 'extdebug' mount option * to get lots of info what's going on */ #define EXT_DEBUG__ #ifdef EXT_DEBUG #define ext_debug(a...) printk(a) #else #define ext_debug(a...) #endif /* * if EXT_STATS is defined then stats numbers are collected * these number will be displayed at umount time */ #define EXT_STATS_ /* * ext4_inode has i_block array (60 bytes total) * first 12 bytes store ext4_extent_header * the remain stores array of ext4_extent */ /* * this is extent on-disk structure * it's used at the bottom of the tree */ struct ext4_extent { __le32 ee_block; /* first logical block extent covers */ __le16 ee_len; /* number of blocks covered by extent */ __le16 ee_start_hi; /* high 16 bits of physical block */ __le32 ee_start; /* low 32 bigs of physical block */ }; /* * this is index on-disk structure * it's used at all the levels, but the bottom */ struct ext4_extent_idx { __le32 ei_block; /* index covers logical blocks from 'block' */ __le32 ei_leaf; /* pointer to the physical block of the next * * level. leaf or next index could bet here */ __le16 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 { __le16 eh_magic; /* probably will support different formats */ __le16 eh_entries; /* number of valid entries */ __le16 eh_max; /* capacity of store in entries */ __le16 eh_depth; /* has tree real underlaying blocks? */ __le32 eh_generation; /* generation of the tree */ }; #define EXT4_EXT_MAGIC cpu_to_le16(0xf30a) /* * 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; __u16 p_depth; 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 */ #define EXT4_EXT_CACHE_NO 0 #define EXT4_EXT_CACHE_GAP 1 #define EXT4_EXT_CACHE_EXTENT 2 /* * to be called by ext4_ext_walk_space() * negative retcode - error * positive retcode - signal for ext4_ext_walk_space(), see below * callback must return valid extent (passed or newly created) */ typedef int (*ext_prepare_callback)(struct inode *, struct ext4_ext_path *, struct ext4_ext_cache *, void *); #define EXT_CONTINUE 0 #define EXT_BREAK 1 #define EXT_REPEAT 2 #define EXT_MAX_BLOCK 0xffffffff #define EXT_MAX_LEN ((1UL << 15) - 1) #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__) \ (le16_to_cpu((__path__)->p_hdr->eh_entries) \ < le16_to_cpu((__path__)->p_hdr->eh_max)) #define EXT_LAST_EXTENT(__hdr__) \ (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1) #define EXT_LAST_INDEX(__hdr__) \ (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1) #define EXT_MAX_EXTENT(__hdr__) \ (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1) #define EXT_MAX_INDEX(__hdr__) \ (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1) static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode) { return (struct ext4_extent_header *) EXT4_I(inode)->i_data; } 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 le16_to_cpu(ext_inode_hdr(inode)->eh_depth); } static inline void ext4_ext_tree_changed(struct inode *inode) { EXT4_I(inode)->i_ext_generation++; } static inline void ext4_ext_invalidate_cache(struct inode *inode) { EXT4_I(inode)->i_cached_extent.ec_type = EXT4_EXT_CACHE_NO; } extern int ext4_extent_tree_init(handle_t *, struct inode *); extern int ext4_ext_calc_credits_for_insert(struct inode *, struct ext4_ext_path *); extern int ext4_ext_insert_extent(handle_t *, struct inode *, struct ext4_ext_path *, struct ext4_extent *); extern int ext4_ext_walk_space(struct inode *, unsigned long, unsigned long, ext_prepare_callback, void *); extern struct ext4_ext_path * ext4_ext_find_extent(struct inode *, int, struct ext4_ext_path *); #endif /* _LINUX_EXT4_EXTENTS */