1/* 2 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com 3 * Written by Alex Tomas <alex@clusterfs.com> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public Licens 15 * along with this program; if not, write to the Free Software 16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111- 17 */ 18 19#ifndef _LINUX_EXT4_EXTENTS 20#define _LINUX_EXT4_EXTENTS 21 22#include <linux/ext4_fs.h> 23 24/* 25 * With AGGRESSIVE_TEST defined, the capacity of index/leaf blocks 26 * becomes very small, so index split, in-depth growing and 27 * other hard changes happen much more often. 28 * This is for debug purposes only. 29 */ 30#define AGGRESSIVE_TEST_ 31 32/* 33 * With EXTENTS_STATS defined, the number of blocks and extents 34 * are collected in the truncate path. They'll be shown at 35 * umount time. 36 */ 37#define EXTENTS_STATS__ 38 39/* 40 * If CHECK_BINSEARCH is defined, then the results of the binary search 41 * will also be checked by linear search. 42 */ 43#define CHECK_BINSEARCH__ 44 45/* 46 * If EXT_DEBUG is defined you can use the 'extdebug' mount option 47 * to get lots of info about what's going on. 48 */ 49#define EXT_DEBUG__ 50#ifdef EXT_DEBUG 51#define ext_debug(a...) printk(a) 52#else 53#define ext_debug(a...) 54#endif 55 56/* 57 * If EXT_STATS is defined then stats numbers are collected. 58 * These number will be displayed at umount time. 59 */ 60#define EXT_STATS_ 61 62 63/* 64 * ext4_inode has i_block array (60 bytes total). 65 * The first 12 bytes store ext4_extent_header; 66 * the remainder stores an array of ext4_extent. 67 */ 68 69/* 70 * This is the extent on-disk structure. 71 * It's used at the bottom of the tree. 72 */ 73struct ext4_extent { 74 __le32 ee_block; /* first logical block extent covers */ 75 __le16 ee_len; /* number of blocks covered by extent */ 76 __le16 ee_start_hi; /* high 16 bits of physical block */ 77 __le32 ee_start; /* low 32 bits of physical block */ 78}; 79 80/* 81 * This is index on-disk structure. 82 * It's used at all the levels except the bottom. 83 */ 84struct ext4_extent_idx { 85 __le32 ei_block; /* index covers logical blocks from 'block' */ 86 __le32 ei_leaf; /* pointer to the physical block of the next * 87 * level. leaf or next index could be there */ 88 __le16 ei_leaf_hi; /* high 16 bits of physical block */ 89 __u16 ei_unused; 90}; 91 92/* 93 * Each block (leaves and indexes), even inode-stored has header. 94 */ 95struct ext4_extent_header { 96 __le16 eh_magic; /* probably will support different formats */ 97 __le16 eh_entries; /* number of valid entries */ 98 __le16 eh_max; /* capacity of store in entries */ 99 __le16 eh_depth; /* has tree real underlying blocks? */ 100 __le32 eh_generation; /* generation of the tree */ 101}; 102 103#define EXT4_EXT_MAGIC cpu_to_le16(0xf30a) 104 105/* 106 * Array of ext4_ext_path contains path to some extent. 107 * Creation/lookup routines use it for traversal/splitting/etc. 108 * Truncate uses it to simulate recursive walking. 109 */ 110struct ext4_ext_path { 111 ext4_fsblk_t p_block; 112 __u16 p_depth; 113 struct ext4_extent *p_ext; 114 struct ext4_extent_idx *p_idx; 115 struct ext4_extent_header *p_hdr; 116 struct buffer_head *p_bh; 117}; 118 119/* 120 * structure for external API 121 */ 122 123#define EXT4_EXT_CACHE_NO 0 124#define EXT4_EXT_CACHE_GAP 1 125#define EXT4_EXT_CACHE_EXTENT 2 126 127/* 128 * to be called by ext4_ext_walk_space() 129 * negative retcode - error 130 * positive retcode - signal for ext4_ext_walk_space(), see below 131 * callback must return valid extent (passed or newly created) 132 */ 133typedef int (*ext_prepare_callback)(struct inode *, struct ext4_ext_path *, 134 struct ext4_ext_cache *, 135 void *); 136 137#define EXT_CONTINUE 0 138#define EXT_BREAK 1 139#define EXT_REPEAT 2 140 141 142#define EXT_MAX_BLOCK 0xffffffff 143 144#define EXT_MAX_LEN ((1UL << 15) - 1) 145 146 147#define EXT_FIRST_EXTENT(__hdr__) \ 148 ((struct ext4_extent *) (((char *) (__hdr__)) + \ 149 sizeof(struct ext4_extent_header))) 150#define EXT_FIRST_INDEX(__hdr__) \ 151 ((struct ext4_extent_idx *) (((char *) (__hdr__)) + \ 152 sizeof(struct ext4_extent_header))) 153#define EXT_HAS_FREE_INDEX(__path__) \ 154 (le16_to_cpu((__path__)->p_hdr->eh_entries) \ 155 < le16_to_cpu((__path__)->p_hdr->eh_max)) 156#define EXT_LAST_EXTENT(__hdr__) \ 157 (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1) 158#define EXT_LAST_INDEX(__hdr__) \ 159 (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1) 160#define EXT_MAX_EXTENT(__hdr__) \ 161 (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1) 162#define EXT_MAX_INDEX(__hdr__) \ 163 (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1) 164 165static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode) 166{ 167 return (struct ext4_extent_header *) EXT4_I(inode)->i_data; 168} 169 170static inline struct ext4_extent_header *ext_block_hdr(struct buffer_head *bh) 171{ 172 return (struct ext4_extent_header *) bh->b_data; 173} 174 175static inline unsigned short ext_depth(struct inode *inode) 176{ 177 return le16_to_cpu(ext_inode_hdr(inode)->eh_depth); 178} 179 180static inline void ext4_ext_tree_changed(struct inode *inode) 181{ 182 EXT4_I(inode)->i_ext_generation++; 183} 184 185static inline void 186ext4_ext_invalidate_cache(struct inode *inode) 187{ 188 EXT4_I(inode)->i_cached_extent.ec_type = EXT4_EXT_CACHE_NO; 189} 190 191extern int ext4_extent_tree_init(handle_t *, struct inode *); 192extern int ext4_ext_calc_credits_for_insert(struct inode *, struct ext4_ext_path *); 193extern unsigned int ext4_ext_check_overlap(struct inode *, struct ext4_extent *, struct ext4_ext_path *); 194extern int ext4_ext_insert_extent(handle_t *, struct inode *, struct ext4_ext_path *, struct ext4_extent *); 195extern int ext4_ext_walk_space(struct inode *, unsigned long, unsigned long, ext_prepare_callback, void *); 196extern struct ext4_ext_path * ext4_ext_find_extent(struct inode *, int, struct ext4_ext_path *); 197 198#endif /* _LINUX_EXT4_EXTENTS */ 199