ext2_extents.c revision 314937
1/*- 2 * Copyright (c) 2010 Zheng Liu <lz@freebsd.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: stable/10/sys/fs/ext2fs/ext2_extents.c 314937 2017-03-09 02:47:01Z pfg $ 27 */ 28 29#include <sys/param.h> 30#include <sys/systm.h> 31#include <sys/types.h> 32#include <sys/kernel.h> 33#include <sys/malloc.h> 34#include <sys/vnode.h> 35#include <sys/bio.h> 36#include <sys/buf.h> 37#include <sys/conf.h> 38 39#include <fs/ext2fs/ext2_mount.h> 40#include <fs/ext2fs/fs.h> 41#include <fs/ext2fs/inode.h> 42#include <fs/ext2fs/ext2fs.h> 43#include <fs/ext2fs/ext2_extents.h> 44#include <fs/ext2fs/ext2_extern.h> 45 46static void ext4_ext_binsearch_index(struct inode *ip, struct ext4_extent_path 47 *path, daddr_t lbn) 48{ 49 struct ext4_extent_header *ehp = path->ep_header; 50 struct ext4_extent_index *l, *r, *m; 51 52 l = (struct ext4_extent_index *)(char *)(ehp + 1); 53 r = (struct ext4_extent_index *)(char *)(ehp + 1) + ehp->eh_ecount - 1; 54 while (l <= r) { 55 m = l + (r - l) / 2; 56 if (lbn < m->ei_blk) 57 r = m - 1; 58 else 59 l = m + 1; 60 } 61 62 path->ep_index = l - 1; 63} 64 65static void 66ext4_ext_binsearch(struct inode *ip, struct ext4_extent_path *path, daddr_t lbn) 67{ 68 struct ext4_extent_header *ehp = path->ep_header; 69 struct ext4_extent *first, *l, *r, *m; 70 71 if (ehp->eh_ecount == 0) 72 return; 73 74 first = (struct ext4_extent *)(char *)(ehp + 1); 75 l = first; 76 r = first + ehp->eh_ecount - 1; 77 while (l <= r) { 78 m = l + (r - l) / 2; 79 if (lbn < m->e_blk) 80 r = m - 1; 81 else 82 l = m + 1; 83 } 84 85 if (l == first) { 86 path->ep_sparse_ext.e_blk = lbn; 87 path->ep_sparse_ext.e_len = first->e_blk - lbn; 88 path->ep_sparse_ext.e_start_hi = 0; 89 path->ep_sparse_ext.e_start_lo = 0; 90 path->ep_is_sparse = 1; 91 return; 92 } 93 path->ep_ext = l - 1; 94 if (path->ep_ext->e_blk + path->ep_ext->e_len <= lbn) { 95 path->ep_sparse_ext.e_blk = lbn; 96 if (l <= (first + ehp->eh_ecount - 1)) 97 path->ep_sparse_ext.e_len = l->e_blk - lbn; 98 else // XXX: where does it end? 99 path->ep_sparse_ext.e_len = 1; 100 path->ep_sparse_ext.e_start_hi = 0; 101 path->ep_sparse_ext.e_start_lo = 0; 102 path->ep_is_sparse = 1; 103 } 104} 105 106/* 107 * Find a block in ext4 extent cache. 108 */ 109int 110ext4_ext_in_cache(struct inode *ip, daddr_t lbn, struct ext4_extent *ep) 111{ 112 struct ext4_extent_cache *ecp; 113 int ret = EXT4_EXT_CACHE_NO; 114 115 ecp = &ip->i_ext_cache; 116 117 /* cache is invalid */ 118 if (ecp->ec_type == EXT4_EXT_CACHE_NO) 119 return (ret); 120 121 if (lbn >= ecp->ec_blk && lbn < ecp->ec_blk + ecp->ec_len) { 122 ep->e_blk = ecp->ec_blk; 123 ep->e_start_lo = ecp->ec_start & 0xffffffff; 124 ep->e_start_hi = ecp->ec_start >> 32 & 0xffff; 125 ep->e_len = ecp->ec_len; 126 ret = ecp->ec_type; 127 } 128 return (ret); 129} 130 131/* 132 * Put an ext4_extent structure in ext4 cache. 133 */ 134void 135ext4_ext_put_cache(struct inode *ip, struct ext4_extent *ep, int type) 136{ 137 struct ext4_extent_cache *ecp; 138 139 ecp = &ip->i_ext_cache; 140 ecp->ec_type = type; 141 ecp->ec_blk = ep->e_blk; 142 ecp->ec_len = ep->e_len; 143 ecp->ec_start = (daddr_t)ep->e_start_hi << 32 | ep->e_start_lo; 144} 145 146/* 147 * Find an extent. 148 */ 149struct ext4_extent_path * 150ext4_ext_find_extent(struct m_ext2fs *fs, struct inode *ip, 151 daddr_t lbn, struct ext4_extent_path *path) 152{ 153 struct ext4_extent_header *ehp; 154 uint16_t i; 155 int error, size; 156 daddr_t nblk; 157 158 ehp = (struct ext4_extent_header *)(char *)ip->i_db; 159 160 if (ehp->eh_magic != EXT4_EXT_MAGIC) 161 return (NULL); 162 163 path->ep_header = ehp; 164 165 for (i = ehp->eh_depth; i != 0; --i) { 166 ext4_ext_binsearch_index(ip, path, lbn); 167 path->ep_depth = 0; 168 path->ep_ext = NULL; 169 170 nblk = (daddr_t)path->ep_index->ei_leaf_hi << 32 | 171 path->ep_index->ei_leaf_lo; 172 size = blksize(fs, ip, nblk); 173 if (path->ep_bp != NULL) { 174 brelse(path->ep_bp); 175 path->ep_bp = NULL; 176 } 177 error = bread(ip->i_devvp, fsbtodb(fs, nblk), size, NOCRED, 178 &path->ep_bp); 179 if (error) { 180 brelse(path->ep_bp); 181 path->ep_bp = NULL; 182 return (NULL); 183 } 184 ehp = (struct ext4_extent_header *)path->ep_bp->b_data; 185 path->ep_header = ehp; 186 } 187 188 path->ep_depth = i; 189 path->ep_ext = NULL; 190 path->ep_index = NULL; 191 path->ep_is_sparse = 0; 192 193 ext4_ext_binsearch(ip, path, lbn); 194 return (path); 195} 196