sys/fs/ext2fs/ext2_extents.c

   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  * $FreeBSD$
  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
  46 static bool
  47 ext4_ext_binsearch_index(struct inode *ip, struct ext4_extent_path *path,
  48     daddr_t lbn, daddr_t *first_lbn, daddr_t *last_lbn){
  49         struct ext4_extent_header *ehp = path->ep_header;
  50         struct ext4_extent_index *first, *last, *l, *r, *m;
  51
  52         first = (struct ext4_extent_index *)(char *)(ehp + 1);
  53         last = first + ehp->eh_ecount - 1;
  54         l = first;
  55         r = last;
  56         while (l <= r) {
  57                 m = l + (r - l) / 2;
  58                 if (lbn < m->ei_blk)
  59                         r = m - 1;
  60                 else
  61                         l = m + 1;
  62         }
  63
  64         if (l == first) {
  65                 path->ep_sparse_ext.e_blk = *first_lbn;
  66                 path->ep_sparse_ext.e_len = first->ei_blk - *first_lbn;
  67                 path->ep_sparse_ext.e_start_hi = 0;
  68                 path->ep_sparse_ext.e_start_lo = 0;
  69                 path->ep_is_sparse = true;
  70                 return (true);
  71         }
  72         path->ep_index = l - 1;
  73         *first_lbn = path->ep_index->ei_blk;
  74         if (path->ep_index < last)
  75                 *last_lbn = l->ei_blk - 1;
  76         return (false);
  77 }
  78
  79 static void
  80 ext4_ext_binsearch(struct inode *ip, struct ext4_extent_path *path, daddr_t lbn,
  81     daddr_t first_lbn, daddr_t last_lbn)
  82 {
  83         struct ext4_extent_header *ehp = path->ep_header;
  84         struct ext4_extent *first, *l, *r, *m;
  85
  86         if (ehp->eh_ecount == 0)
  87                 return;
  88
  89         first = (struct ext4_extent *)(char *)(ehp + 1);
  90         l = first;
  91         r = first + ehp->eh_ecount - 1;
  92         while (l <= r) {
  93                 m = l + (r - l) / 2;
  94                 if (lbn < m->e_blk)
  95                         r = m - 1;
  96                 else
  97                         l = m + 1;
  98         }
  99
 100         if (l == first) {
 101                 path->ep_sparse_ext.e_blk = first_lbn;
 102                 path->ep_sparse_ext.e_len = first->e_blk - first_lbn;
 103                 path->ep_sparse_ext.e_start_hi = 0;
 104                 path->ep_sparse_ext.e_start_lo = 0;
 105                 path->ep_is_sparse = true;
 106                 return;
 107         }
 108         path->ep_ext = l - 1;
 109         if (path->ep_ext->e_blk + path->ep_ext->e_len <= lbn) {
 110                 path->ep_sparse_ext.e_blk = path->ep_ext->e_blk +
 111                     path->ep_ext->e_len;
 112                 if (l <= (first + ehp->eh_ecount - 1))
 113                         path->ep_sparse_ext.e_len = l->e_blk -
 114                             path->ep_sparse_ext.e_blk;
 115                 else
 116                         path->ep_sparse_ext.e_len = last_lbn -
 117                             path->ep_sparse_ext.e_blk + 1;
 118                 path->ep_sparse_ext.e_start_hi = 0;
 119                 path->ep_sparse_ext.e_start_lo = 0;
 120                 path->ep_is_sparse = true;
 121         }
 122 }
 123
 124 /*
 125  * Find a block in ext4 extent cache.
 126  */
 127 int
 128 ext4_ext_in_cache(struct inode *ip, daddr_t lbn, struct ext4_extent *ep)
 129 {
 130         struct ext4_extent_cache *ecp;
 131         int ret = EXT4_EXT_CACHE_NO;
 132
 133         ecp = &ip->i_ext_cache;
 134
 135         /* cache is invalid */
 136         if (ecp->ec_type == EXT4_EXT_CACHE_NO)
 137                 return (ret);
 138
 139         if (lbn >= ecp->ec_blk && lbn < ecp->ec_blk + ecp->ec_len) {
 140                 ep->e_blk = ecp->ec_blk;
 141                 ep->e_start_lo = ecp->ec_start & 0xffffffff;
 142                 ep->e_start_hi = ecp->ec_start >> 32 & 0xffff;
 143                 ep->e_len = ecp->ec_len;
 144                 ret = ecp->ec_type;
 145         }
 146         return (ret);
 147 }
 148
 149 /*
 150  * Put an ext4_extent structure in ext4 cache.
 151  */
 152 void
 153 ext4_ext_put_cache(struct inode *ip, struct ext4_extent *ep, int type)
 154 {
 155         struct ext4_extent_cache *ecp;
 156
 157         ecp = &ip->i_ext_cache;
 158         ecp->ec_type = type;
 159         ecp->ec_blk = ep->e_blk;
 160         ecp->ec_len = ep->e_len;
 161         ecp->ec_start = (daddr_t)ep->e_start_hi << 32 | ep->e_start_lo;
 162 }
 163
 164 /*
 165  * Find an extent.
 166  */
 167 struct ext4_extent_path *
 168 ext4_ext_find_extent(struct m_ext2fs *fs, struct inode *ip,
 169     daddr_t lbn, struct ext4_extent_path *path)
 170 {
 171         struct ext4_extent_header *ehp;
 172         uint16_t i;
 173         int error, size;
 174         daddr_t nblk;
 175
 176         ehp = (struct ext4_extent_header *)(char *)ip->i_db;
 177
 178         if (ehp->eh_magic != EXT4_EXT_MAGIC)
 179                 return (NULL);
 180
 181         path->ep_header = ehp;
 182
 183         daddr_t first_lbn = 0;
 184         daddr_t last_lbn = lblkno(ip->i_e2fs, ip->i_size);
 185
 186         for (i = ehp->eh_depth; i != 0; --i) {
 187                 path->ep_depth = i;
 188                 path->ep_ext = NULL;
 189                 if (ext4_ext_binsearch_index(ip, path, lbn, &first_lbn,
 190                     &last_lbn)) {
 191                         return (path);
 192                 }
 193
 194                 nblk = (daddr_t)path->ep_index->ei_leaf_hi << 32 |
 195                     path->ep_index->ei_leaf_lo;
 196                 size = blksize(fs, ip, nblk);
 197                 if (path->ep_bp != NULL) {
 198                         brelse(path->ep_bp);
 199                         path->ep_bp = NULL;
 200                 }
 201                 error = bread(ip->i_devvp, fsbtodb(fs, nblk), size, NOCRED,
 202                     &path->ep_bp);
 203                 if (error) {
 204                         brelse(path->ep_bp);
 205                         path->ep_bp = NULL;
 206                         return (NULL);
 207                 }
 208                 ehp = (struct ext4_extent_header *)path->ep_bp->b_data;
 209                 path->ep_header = ehp;
 210         }
 211
 212         path->ep_depth = i;
 213         path->ep_ext = NULL;
 214         path->ep_index = NULL;
 215         path->ep_is_sparse = false;
 216
 217         ext4_ext_binsearch(ip, path, lbn, first_lbn, last_lbn);
 218         return (path);
 219 }