Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/fs/ext2fs/ext2_balloc.c
Version:
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1 /*- 2 * modified for Lites 1.1 3 * 4 * Aug 1995, Godmar Back (gback@cs.utah.edu) 5 * University of Utah, Department of Computer Science 6 */ 7 /*- 8 * Copyright (c) 1982, 1986, 1989, 1993 9 * The Regents of the University of California. All rights reserved. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)ffs_balloc.c 8.4 (Berkeley) 9/23/93 36 * $FreeBSD$ 37 */ 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/bio.h> 42 #include <sys/buf.h> 43 #include <sys/lock.h> 44 #include <sys/mount.h> 45 #include <sys/vnode.h> 46 47 #include <fs/ext2fs/fs.h> 48 #include <fs/ext2fs/inode.h> 49 #include <fs/ext2fs/ext2fs.h> 50 #include <fs/ext2fs/ext2_dinode.h> 51 #include <fs/ext2fs/ext2_extern.h> 52 #include <fs/ext2fs/ext2_mount.h> 53 54 /* 55 * Balloc defines the structure of filesystem storage 56 * by allocating the physical blocks on a device given 57 * the inode and the logical block number in a file. 58 */ 59 int 60 ext2_balloc(struct inode *ip, e2fs_lbn_t lbn, int size, struct ucred *cred, 61 struct buf **bpp, int flags) 62 { 63 struct m_ext2fs *fs; 64 struct ext2mount *ump; 65 struct buf *bp, *nbp; 66 struct vnode *vp = ITOV(ip); 67 struct indir indirs[NIADDR + 2]; 68 e4fs_daddr_t nb, newb; 69 e2fs_daddr_t *bap, pref; 70 int num, i, error; 71 72 *bpp = NULL; 73 if (lbn < 0) 74 return (EFBIG); 75 fs = ip->i_e2fs; 76 ump = ip->i_ump; 77 78 /* 79 * check if this is a sequential block allocation. 80 * If so, increment next_alloc fields to allow ext2_blkpref 81 * to make a good guess 82 */ 83 if (lbn == ip->i_next_alloc_block + 1) { 84 ip->i_next_alloc_block++; 85 ip->i_next_alloc_goal++; 86 } 87 /* 88 * The first NDADDR blocks are direct blocks 89 */ 90 if (lbn < NDADDR) { 91 nb = ip->i_db[lbn]; 92 /* 93 * no new block is to be allocated, and no need to expand 94 * the file 95 */ 96 if (nb != 0) { 97 error = bread(vp, lbn, fs->e2fs_bsize, NOCRED, &bp); 98 if (error) { 99 brelse(bp); 100 return (error); 101 } 102 bp->b_blkno = fsbtodb(fs, nb); 103 if (ip->i_size >= (lbn + 1) * fs->e2fs_bsize) { 104 *bpp = bp; 105 return (0); 106 } 107 } else { 108 EXT2_LOCK(ump); 109 error = ext2_alloc(ip, lbn, 110 ext2_blkpref(ip, lbn, (int)lbn, &ip->i_db[0], 0), 111 fs->e2fs_bsize, cred, &newb); 112 if (error) 113 return (error); 114 bp = getblk(vp, lbn, fs->e2fs_bsize, 0, 0, 0); 115 bp->b_blkno = fsbtodb(fs, newb); 116 if (flags & BA_CLRBUF) 117 vfs_bio_clrbuf(bp); 118 } 119 ip->i_db[lbn] = dbtofsb(fs, bp->b_blkno); 120 ip->i_flag |= IN_CHANGE | IN_UPDATE; 121 *bpp = bp; 122 return (0); 123 } 124 /* 125 * Determine the number of levels of indirection. 126 */ 127 pref = 0; 128 if ((error = ext2_getlbns(vp, lbn, indirs, &num)) != 0) 129 return (error); 130 #ifdef INVARIANTS 131 if (num < 1) 132 panic("ext2_balloc: ext2_getlbns returned indirect block"); 133 #endif 134 /* 135 * Fetch the first indirect block allocating if necessary. 136 */ 137 --num; 138 nb = ip->i_ib[indirs[0].in_off]; 139 if (nb == 0) { 140 EXT2_LOCK(ump); 141 pref = ext2_blkpref(ip, lbn, indirs[0].in_off + 142 EXT2_NDIR_BLOCKS, &ip->i_db[0], 0); 143 if ((error = ext2_alloc(ip, lbn, pref, fs->e2fs_bsize, cred, 144 &newb))) 145 return (error); 146 nb = newb; 147 bp = getblk(vp, indirs[1].in_lbn, fs->e2fs_bsize, 0, 0, 0); 148 bp->b_blkno = fsbtodb(fs, newb); 149 vfs_bio_clrbuf(bp); 150 /* 151 * Write synchronously so that indirect blocks 152 * never point at garbage. 153 */ 154 if ((error = bwrite(bp)) != 0) { 155 ext2_blkfree(ip, nb, fs->e2fs_bsize); 156 return (error); 157 } 158 ip->i_ib[indirs[0].in_off] = newb; 159 ip->i_flag |= IN_CHANGE | IN_UPDATE; 160 } 161 /* 162 * Fetch through the indirect blocks, allocating as necessary. 163 */ 164 for (i = 1;;) { 165 error = bread(vp, 166 indirs[i].in_lbn, (int)fs->e2fs_bsize, NOCRED, &bp); 167 if (error) { 168 brelse(bp); 169 return (error); 170 } 171 bap = (e2fs_daddr_t *)bp->b_data; 172 nb = bap[indirs[i].in_off]; 173 if (i == num) 174 break; 175 i += 1; 176 if (nb != 0) { 177 bqrelse(bp); 178 continue; 179 } 180 EXT2_LOCK(ump); 181 if (pref == 0) 182 pref = ext2_blkpref(ip, lbn, indirs[i].in_off, bap, 183 bp->b_lblkno); 184 error = ext2_alloc(ip, lbn, pref, (int)fs->e2fs_bsize, cred, &newb); 185 if (error) { 186 brelse(bp); 187 return (error); 188 } 189 nb = newb; 190 nbp = getblk(vp, indirs[i].in_lbn, fs->e2fs_bsize, 0, 0, 0); 191 nbp->b_blkno = fsbtodb(fs, nb); 192 vfs_bio_clrbuf(nbp); 193 /* 194 * Write synchronously so that indirect blocks 195 * never point at garbage. 196 */ 197 if ((error = bwrite(nbp)) != 0) { 198 ext2_blkfree(ip, nb, fs->e2fs_bsize); 199 brelse(bp); 200 return (error); 201 } 202 bap[indirs[i - 1].in_off] = nb; 203 /* 204 * If required, write synchronously, otherwise use 205 * delayed write. 206 */ 207 if (flags & IO_SYNC) { 208 bwrite(bp); 209 } else { 210 if (bp->b_bufsize == fs->e2fs_bsize) 211 bp->b_flags |= B_CLUSTEROK; 212 bdwrite(bp); 213 } 214 } 215 /* 216 * Get the data block, allocating if necessary. 217 */ 218 if (nb == 0) { 219 EXT2_LOCK(ump); 220 pref = ext2_blkpref(ip, lbn, indirs[i].in_off, &bap[0], 221 bp->b_lblkno); 222 if ((error = ext2_alloc(ip, 223 lbn, pref, (int)fs->e2fs_bsize, cred, &newb)) != 0) { 224 brelse(bp); 225 return (error); 226 } 227 nb = newb; 228 nbp = getblk(vp, lbn, fs->e2fs_bsize, 0, 0, 0); 229 nbp->b_blkno = fsbtodb(fs, nb); 230 if (flags & BA_CLRBUF) 231 vfs_bio_clrbuf(nbp); 232 bap[indirs[i].in_off] = nb; 233 /* 234 * If required, write synchronously, otherwise use 235 * delayed write. 236 */ 237 if (flags & IO_SYNC) { 238 bwrite(bp); 239 } else { 240 if (bp->b_bufsize == fs->e2fs_bsize) 241 bp->b_flags |= B_CLUSTEROK; 242 bdwrite(bp); 243 } 244 *bpp = nbp; 245 return (0); 246 } 247 brelse(bp); 248 if (flags & BA_CLRBUF) { 249 int seqcount = (flags & BA_SEQMASK) >> BA_SEQSHIFT; 250 251 if (seqcount && (vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) { 252 error = cluster_read(vp, ip->i_size, lbn, 253 (int)fs->e2fs_bsize, NOCRED, 254 MAXBSIZE, seqcount, 0, &nbp); 255 } else { 256 error = bread(vp, lbn, (int)fs->e2fs_bsize, NOCRED, &nbp); 257 } 258 if (error) { 259 brelse(nbp); 260 return (error); 261 } 262 } else { 263 nbp = getblk(vp, lbn, fs->e2fs_bsize, 0, 0, 0); 264 nbp->b_blkno = fsbtodb(fs, nb); 265 } 266 *bpp = nbp; 267 return (0); 268 }
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