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 {
  50         struct ext4_extent_header *ehp = path->ep_header;
  51         struct ext4_extent_index *first, *last, *l, *r, *m;
  52
  53         first = (struct ext4_extent_index *)(char *)(ehp + 1);
  54         last = first + ehp->eh_ecount - 1;
  55         l = first;
  56         r = last;
  57         while (l <= r) {
  58                 m = l + (r - l) / 2;
  59                 if (lbn < m->ei_blk)
  60                         r = m - 1;
  61                 else
  62                         l = m + 1;
  63         }
  64
  65         if (l == first) {
  66                 path->ep_sparse_ext.e_blk = *first_lbn;
  67                 path->ep_sparse_ext.e_len = first->ei_blk - *first_lbn;
  68                 path->ep_sparse_ext.e_start_hi = 0;
  69                 path->ep_sparse_ext.e_start_lo = 0;
  70                 path->ep_is_sparse = true;
  71                 return (true);
  72         }
  73         path->ep_index = l - 1;
  74         *first_lbn = path->ep_index->ei_blk;
  75         if (path->ep_index < last)
  76                 *last_lbn = l->ei_blk - 1;
  77         return (false);
  78 }
  79
  80 static void
  81 ext4_ext_binsearch(struct inode *ip, struct ext4_extent_path *path, daddr_t lbn,
  82                 daddr_t first_lbn, daddr_t last_lbn)
  83 {
  84         struct ext4_extent_header *ehp = path->ep_header;
  85         struct ext4_extent *first, *l, *r, *m;
  86
  87         if (ehp->eh_ecount == 0)
  88                 return;
  89
  90         first = (struct ext4_extent *)(char *)(ehp + 1);
  91         l = first;
  92         r = first + ehp->eh_ecount - 1;
  93         while (l <= r) {
  94                 m = l + (r - l) / 2;
  95                 if (lbn < m->e_blk)
  96                         r = m - 1;
  97                 else
  98                         l = m + 1;
  99         }
 100
 101         if (l == first) {
 102                 path->ep_sparse_ext.e_blk = first_lbn;
 103                 path->ep_sparse_ext.e_len = first->e_blk - first_lbn;
 104                 path->ep_sparse_ext.e_start_hi = 0;
 105                 path->ep_sparse_ext.e_start_lo = 0;
 106                 path->ep_is_sparse = true;
 107                 return;
 108         }
 109         path->ep_ext = l - 1;
 110         if (path->ep_ext->e_blk + path->ep_ext->e_len <= lbn) {
 111                 path->ep_sparse_ext.e_blk = path->ep_ext->e_blk +
 112                     path->ep_ext->e_len;
 113                 if (l <= (first + ehp->eh_ecount - 1))
 114                         path->ep_sparse_ext.e_len = l->e_blk -
 115                             path->ep_sparse_ext.e_blk;
 116                 else
 117                         path->ep_sparse_ext.e_len = last_lbn -
 118                             path->ep_sparse_ext.e_blk + 1;
 119                 path->ep_sparse_ext.e_start_hi = 0;
 120                 path->ep_sparse_ext.e_start_lo = 0;
 121                 path->ep_is_sparse = true;
 122         }
 123 }
 124
 125 /*
 126  * Find a block in ext4 extent cache.
 127  */
 128 int
 129 ext4_ext_in_cache(struct inode *ip, daddr_t lbn, struct ext4_extent *ep)
 130 {
 131         struct ext4_extent_cache *ecp;
 132         int ret = EXT4_EXT_CACHE_NO;
 133
 134         ecp = &ip->i_ext_cache;
 135
 136         /* cache is invalid */
 137         if (ecp->ec_type == EXT4_EXT_CACHE_NO)
 138                 return (ret);
 139
 140         if (lbn >= ecp->ec_blk && lbn < ecp->ec_blk + ecp->ec_len) {
 141                 ep->e_blk = ecp->ec_blk;
 142                 ep->e_start_lo = ecp->ec_start & 0xffffffff;
 143                 ep->e_start_hi = ecp->ec_start >> 32 & 0xffff;
 144                 ep->e_len = ecp->ec_len;
 145                 ret = ecp->ec_type;
 146         }
 147         return (ret);
 148 }
 149
 150 /*
 151  * Put an ext4_extent structure in ext4 cache.
 152  */
 153 void
 154 ext4_ext_put_cache(struct inode *ip, struct ext4_extent *ep, int type)
 155 {
 156         struct ext4_extent_cache *ecp;
 157
 158         ecp = &ip->i_ext_cache;
 159         ecp->ec_type = type;
 160         ecp->ec_blk = ep->e_blk;
 161         ecp->ec_len = ep->e_len;
 162         ecp->ec_start = (daddr_t)ep->e_start_hi << 32 | ep->e_start_lo;
 163 }
 164
 165 /*
 166  * Find an extent.
 167  */
 168 struct ext4_extent_path *
 169 ext4_ext_find_extent(struct m_ext2fs *fs, struct inode *ip,
 170                      daddr_t lbn, struct ext4_extent_path *path)
 171 {
 172         struct ext4_extent_header *ehp;
 173         uint16_t i;
 174         int error, size;
 175         daddr_t nblk;
 176
 177         ehp = (struct ext4_extent_header *)(char *)ip->i_db;
 178
 179         if (ehp->eh_magic != EXT4_EXT_MAGIC)
 180                 return (NULL);
 181
 182         path->ep_header = ehp;
 183
 184         daddr_t first_lbn = 0;
 185         daddr_t last_lbn = lblkno(ip->i_e2fs, ip->i_size);
 186
 187         for (i = ehp->eh_depth; i != 0; --i) {
 188                 path->ep_depth = i;
 189                 path->ep_ext = NULL;
 190                 if (ext4_ext_binsearch_index(ip, path, lbn, &first_lbn,
 191                     &last_lbn)) {
 192                         return (path);
 193                 }
 194
 195                 nblk = (daddr_t)path->ep_index->ei_leaf_hi << 32 |
 196                     path->ep_index->ei_leaf_lo;
 197                 size = blksize(fs, ip, nblk);
 198                 if (path->ep_bp != NULL) {
 199                         brelse(path->ep_bp);
 200                         path->ep_bp = NULL;
 201                 }
 202                 error = bread(ip->i_devvp, fsbtodb(fs, nblk), size, NOCRED,
 203                             &path->ep_bp);
 204                 if (error) {
 205                         brelse(path->ep_bp);
 206                         path->ep_bp = NULL;
 207                         return (NULL);
 208                 }
 209                 ehp = (struct ext4_extent_header *)path->ep_bp->b_data;
 210                 path->ep_header = ehp;
 211         }
 212
 213         path->ep_depth = i;
 214         path->ep_ext = NULL;
 215         path->ep_index = NULL;
 216         path->ep_is_sparse = false;
 217
 218         ext4_ext_binsearch(ip, path, lbn, first_lbn, last_lbn);
 219         return (path);
 220 }