1 /* 2 * Copyright (c) 1989, 1991 Regents of the University of California. 3 * All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 * 7 * @(#)lfs_balloc.c 7.27 (Berkeley) 03/18/92 8 */ 9 10 #include <sys/param.h> 11 #include <sys/buf.h> 12 #include <sys/proc.h> 13 #include <sys/vnode.h> 14 #include <sys/mount.h> 15 #include <sys/resourcevar.h> 16 #include <sys/specdev.h> 17 #include <sys/trace.h> 18 19 #include <ufs/ufs/quota.h> 20 #include <ufs/ufs/inode.h> 21 #include <ufs/ufs/ufsmount.h> 22 23 #include <ufs/lfs/lfs.h> 24 #include <ufs/lfs/lfs_extern.h> 25 26 int lfs_getlbns __P((struct vnode *, daddr_t, INDIR *, int *)); 27 28 /* 29 * Bmap converts a the logical block number of a file to its physical block 30 * number on the disk. The conversion is done by using the logical block 31 * number to index into the array of block pointers described by the dinode. 32 */ 33 int 34 lfs_bmap(vp, bn, vpp, bnp) 35 struct vnode *vp; 36 register daddr_t bn; 37 struct vnode **vpp; 38 daddr_t *bnp; 39 { 40 #ifdef VERBOSE 41 printf("lfs_bmap\n"); 42 #endif 43 /* 44 * Check for underlying vnode requests and ensure that logical 45 * to physical mapping is requested. 46 */ 47 if (vpp != NULL) 48 *vpp = VTOI(vp)->i_devvp; 49 if (bnp == NULL) 50 return (0); 51 52 return (lfs_bmaparray(vp, bn, bnp, NULL, NULL)); 53 } 54 55 /* 56 * LFS has a different version of bmap from FFS because of a naming conflict. 57 * In FFS, meta blocks are given real disk addresses at allocation time, and 58 * are linked into the device vnode, using a logical block number which is 59 * the same as the physical block number. This can't be done by LFS because 60 * blocks aren't given disk addresses until they're written, so there's no 61 * way to distinguish the meta-data blocks for one file from any other file. 62 * This means that meta-data blocks have to be on the vnode for the file so 63 * they can be found, and have to have "names" different from the standard 64 * data blocks. To do this, we divide the name space into positive and 65 * negative block numbers, and give the meta-data blocks negative logical 66 * numbers. Indirect blocks are addressed by the negative address of the 67 * first data block to which they point. Double indirect blocks are addressed 68 * by one less than the address of the first indirect block to which they 69 * point. Triple indirect blocks are addressed by one less than the address 70 * of the first double indirect block to which they point. 71 */ 72 int 73 lfs_bmaparray(vp, bn, bnp, ap, nump) 74 struct vnode *vp; 75 register daddr_t bn; 76 daddr_t *bnp; 77 INDIR *ap; 78 int *nump; 79 { 80 register struct inode *ip; 81 struct buf *bp; 82 struct lfs *fs; 83 struct vnode *devvp; 84 INDIR a[NIADDR], *xap; 85 daddr_t *bap, daddr; 86 long metalbn; 87 int error, num, off; 88 89 90 ip = VTOI(vp); 91 #ifdef VERBOSE 92 printf("lfs_bmap: block number %d, inode %d\n", bn, ip->i_number); 93 #endif 94 #ifdef DIAGNOSTIC 95 if (ap != NULL && nump == NULL || ap == NULL && nump != NULL) 96 panic("lfs_bmaparray: invalid arguments"); 97 #endif 98 99 xap = ap == NULL ? a : ap; 100 if (error = lfs_getlbns(vp, bn, xap, nump)) 101 return (error); 102 103 num = *nump; 104 105 if (num == 0) { 106 *bnp = ip->i_db[bn]; 107 if (*bnp == 0) 108 *bnp = UNASSIGNED; 109 return (0); 110 } 111 112 113 /* Get disk address out of indirect block array */ 114 daddr = ip->i_ib[xap->in_off]; 115 116 /* Fetch through the indirect blocks. */ 117 fs = ip->i_lfs; 118 devvp = VFSTOUFS(vp->v_mount)->um_devvp; 119 120 for (bp = NULL, ++xap; daddr && --num; ++xap) { 121 /* If looking for a meta-block, break out when we find it. */ 122 metalbn = xap->in_lbn; 123 if (metalbn == bn) 124 break; 125 126 /* 127 * Read in the appropriate indirect block. LFS can't do a 128 * bread because bread knows that FFS will hand it the device 129 * vnode, not the file vnode, so the b_dev and b_blkno would 130 * be wrong. 131 * 132 * XXX 133 * This REALLY needs to be fixed, at the very least it needs 134 * to be rethought when the buffer cache goes away. When it's 135 * fixed, change lfs_bmaparray and lfs_getlbns to take an ip, 136 * not a vp. 137 */ 138 if (bp) 139 brelse(bp); 140 bp = getblk(vp, metalbn, fs->lfs_bsize); 141 if (bp->b_flags & (B_DONE | B_DELWRI)) { 142 trace(TR_BREADHIT, pack(vp, size), metalbn); 143 } else { 144 trace(TR_BREADMISS, pack(vp, size), metalbn); 145 bp->b_blkno = daddr; 146 bp->b_flags |= B_READ; 147 bp->b_dev = devvp->v_rdev; 148 (devvp->v_op->vop_strategy)(bp); 149 curproc->p_stats->p_ru.ru_inblock++; /* XXX */ 150 if (error = biowait(bp)) { 151 brelse(bp); 152 return (error); 153 } 154 } 155 daddr = bp->b_un.b_daddr[xap->in_off]; 156 } 157 if (bp) 158 brelse(bp); 159 160 *bnp = daddr == 0 ? UNASSIGNED : daddr; 161 return (0); 162 } 163 164 /* 165 * Create an array of logical block number/offset pairs which represent the 166 * path of indirect blocks required to access a data block. The first "pair" 167 * contains the logical block number of the appropriate single, double or 168 * triple indirect block and the offset into the inode indirect block array. 169 * Note, the logical block number of the inode single/double/triple indirect 170 * block appears twice in the array, once with the offset into the i_ib and 171 * once with the offset into the page itself. 172 */ 173 int 174 lfs_getlbns(vp, bn, ap, nump) 175 struct vnode *vp; 176 register daddr_t bn; 177 INDIR *ap; 178 int *nump; 179 { 180 struct lfs *fs; 181 long metalbn, realbn; 182 int j, off, sh; 183 184 #ifdef VERBOSE 185 printf("lfs_getlbns: bn %d, inode %d\n", bn, VTOI(vp)->i_number); 186 #endif 187 *nump = 0; 188 realbn = bn; 189 if ((long)bn < 0) 190 bn = -(long)bn; 191 192 /* The first NDADDR blocks are direct blocks. */ 193 if (bn < NDADDR) 194 return (0); 195 196 /* 197 * Determine the number of levels of indirection. After this loop 198 * is done, sh indicates the number of data blocks possible at the 199 * given level of indirection, and NIADDR - j is the number of levels 200 * of indirection needed to locate the requested block. 201 */ 202 bn -= NDADDR; 203 fs = VTOI(vp)->i_lfs; 204 sh = 1; 205 for (j = NIADDR; j > 0; j--) { 206 sh *= NINDIR(fs); 207 if (bn < sh) 208 break; 209 bn -= sh; 210 } 211 if (j == 0) 212 return (EFBIG); 213 214 /* Calculate the address of the first meta-block. */ 215 if (realbn >= 0) 216 metalbn = -(realbn - bn + NIADDR - j); 217 else 218 metalbn = -(-realbn - bn + NIADDR - j); 219 220 /* 221 * At each iteration, off is the offset into the bap array which is 222 * an array of disk addresses at the current level of indirection. 223 * The logical block number and the offset in that block are stored 224 * into the argument array. 225 */ 226 ++*nump; 227 ap->in_lbn = metalbn; 228 ap->in_off = off = NIADDR - j; 229 ap++; 230 for (; j <= NIADDR; j++) { 231 /* If searching for a meta-data block, quit when found. */ 232 if (metalbn == realbn) 233 break; 234 235 sh /= NINDIR(fs); 236 off = (bn / sh) % NINDIR(fs); 237 238 ++*nump; 239 ap->in_lbn = metalbn; 240 ap->in_off = off; 241 ++ap; 242 243 metalbn -= -1 + off * sh; 244 } 245 return (0); 246 } 247 248 int 249 lfs_balloc(vp, iosize, lbn, bpp) 250 struct vnode *vp; 251 u_long iosize; 252 daddr_t lbn; 253 struct buf **bpp; 254 { 255 struct buf *bp; 256 struct inode *ip; 257 struct lfs *fs; 258 daddr_t daddr; 259 int error, newblock; 260 261 ip = VTOI(vp); 262 fs = ip->i_lfs; 263 264 /* 265 * Three cases: it's a block beyond the end of file, it's a block in 266 * the file that may or may not have been assigned a disk address or 267 * we're writing an entire block. Note, if the daddr is unassigned, 268 * the block might still have existed in the cache. If it did, make 269 * sure we don't count it as a new block or zero out its contents. 270 */ 271 newblock = ip->i_size <= lbn << fs->lfs_bshift; 272 if (!newblock && (error = lfs_bmap(vp, lbn, NULL, &daddr))) 273 return (error); 274 275 if (newblock || daddr == UNASSIGNED || iosize == fs->lfs_bsize) { 276 *bpp = bp = getblk(vp, lbn, fs->lfs_bsize); 277 if (newblock || 278 daddr == UNASSIGNED && !(bp->b_flags & B_CACHE)) { 279 ++ip->i_blocks; 280 if (iosize != fs->lfs_bsize) 281 clrbuf(bp); 282 } 283 return (0); 284 } 285 return (bread(vp, lbn, fs->lfs_bsize, NOCRED, bpp)); 286 287 } 288