111a9947fSrtm #include "types.h" 211a9947fSrtm #include "param.h" 311a9947fSrtm #include "x86.h" 411a9947fSrtm #include "mmu.h" 511a9947fSrtm #include "proc.h" 611a9947fSrtm #include "defs.h" 711a9947fSrtm #include "spinlock.h" 811a9947fSrtm #include "buf.h" 911a9947fSrtm #include "fs.h" 1011a9947fSrtm #include "fsvar.h" 1111a9947fSrtm 1211a9947fSrtm // these are inodes currently in use 1311a9947fSrtm // an entry is free if count == 0 1411a9947fSrtm struct inode inode[NINODE]; 1532630628Srtm struct spinlock inode_table_lock = { "inode_table" }; 1611a9947fSrtm 179d3fb671Srtm uint rootdev = 1; 189d3fb671Srtm 19*24111398Skaashoek static uint 20*24111398Skaashoek balloc(uint dev) 21*24111398Skaashoek { 22*24111398Skaashoek int b; 23*24111398Skaashoek struct buf *bp; 24*24111398Skaashoek struct superblock *sb; 25*24111398Skaashoek int bi; 26*24111398Skaashoek int size; 27*24111398Skaashoek int ninodes; 28*24111398Skaashoek uchar m; 29*24111398Skaashoek 30*24111398Skaashoek bp = bread(dev, 1); 31*24111398Skaashoek sb = (struct superblock *) bp->data; 32*24111398Skaashoek size = sb->size; 33*24111398Skaashoek ninodes = sb->ninodes; 34*24111398Skaashoek 35*24111398Skaashoek for (b = 0; b < size; b++) { 36*24111398Skaashoek if (b % BPB == 0) { 37*24111398Skaashoek brelse(bp); 38*24111398Skaashoek bp = bread(dev, BBLOCK(b, ninodes)); 39*24111398Skaashoek } 40*24111398Skaashoek bi = b % BPB; 41*24111398Skaashoek m = 0x1 << (bi % 8); 42*24111398Skaashoek if ((bp->data[bi/8] & m) == 0) { // is block free? 43*24111398Skaashoek break; 44*24111398Skaashoek } 45*24111398Skaashoek } 46*24111398Skaashoek if (b >= size) 47*24111398Skaashoek panic("balloc: out of blocks\n"); 48*24111398Skaashoek 49*24111398Skaashoek cprintf ("balloc: allocate block %d\n", b); 50*24111398Skaashoek bp->data[bi/8] |= 0x1 << (bi % 8); 51*24111398Skaashoek bwrite (dev, bp, BBLOCK(b, ninodes)); // mark it allocated on disk 52*24111398Skaashoek return b; 53*24111398Skaashoek } 54*24111398Skaashoek 55*24111398Skaashoek 569d3fb671Srtm // returns an inode with busy set and incremented reference count. 5711a9947fSrtm struct inode * 5811a9947fSrtm iget(uint dev, uint inum) 5911a9947fSrtm { 6011a9947fSrtm struct inode *ip, *nip = 0; 6111a9947fSrtm struct dinode *dip; 6211a9947fSrtm struct buf *bp; 6311a9947fSrtm 6411a9947fSrtm acquire(&inode_table_lock); 6511a9947fSrtm 6611a9947fSrtm loop: 6711a9947fSrtm for(ip = &inode[0]; ip < &inode[NINODE]; ip++){ 6811a9947fSrtm if(ip->count > 0 && ip->dev == dev && ip->inum == inum){ 6911a9947fSrtm if(ip->busy){ 7011a9947fSrtm sleep(ip, &inode_table_lock); 7111a9947fSrtm goto loop; 7211a9947fSrtm } 7311a9947fSrtm ip->count++; 7411a9947fSrtm release(&inode_table_lock); 7511a9947fSrtm return ip; 7611a9947fSrtm } 7711a9947fSrtm if(nip == 0 && ip->count == 0) 7811a9947fSrtm nip = ip; 7911a9947fSrtm } 8011a9947fSrtm 8111a9947fSrtm if(nip == 0) 8211a9947fSrtm panic("out of inodes"); 8311a9947fSrtm 8411a9947fSrtm nip->dev = dev; 8511a9947fSrtm nip->inum = inum; 8611a9947fSrtm nip->count = 1; 8711a9947fSrtm nip->busy = 1; 8811a9947fSrtm 8911a9947fSrtm release(&inode_table_lock); 9011a9947fSrtm 91*24111398Skaashoek bp = bread(dev, IBLOCK(inum)); 9211a9947fSrtm dip = &((struct dinode *)(bp->data))[inum % IPB]; 9311a9947fSrtm nip->type = dip->type; 94e8d11c2eSkaashoek nip->major = dip->major; 95e8d11c2eSkaashoek nip->minor = dip->minor; 9611a9947fSrtm nip->nlink = dip->nlink; 9711a9947fSrtm nip->size = dip->size; 9811a9947fSrtm memmove(nip->addrs, dip->addrs, sizeof(nip->addrs)); 9911a9947fSrtm brelse(bp); 10011a9947fSrtm 10111a9947fSrtm return nip; 10211a9947fSrtm } 10311a9947fSrtm 104e8d11c2eSkaashoek // allocate an inode on disk 105e8d11c2eSkaashoek struct inode * 106e8d11c2eSkaashoek ialloc(uint dev, short type) 107e8d11c2eSkaashoek { 108e8d11c2eSkaashoek struct inode *ip; 109e8d11c2eSkaashoek struct dinode *dip = 0; 110e8d11c2eSkaashoek struct superblock *sb; 111e8d11c2eSkaashoek int ninodes; 112e8d11c2eSkaashoek int inum; 113e8d11c2eSkaashoek struct buf *bp; 114e8d11c2eSkaashoek 115e8d11c2eSkaashoek bp = bread(dev, 1); 116*24111398Skaashoek sb = (struct superblock *) bp->data; 117e8d11c2eSkaashoek ninodes = sb->ninodes; 118e8d11c2eSkaashoek brelse(bp); 119e8d11c2eSkaashoek 120e8d11c2eSkaashoek for (inum = 1; inum < ninodes; inum++) { // loop over inode blocks 121*24111398Skaashoek bp = bread(dev, IBLOCK(inum)); 122e8d11c2eSkaashoek dip = &((struct dinode *)(bp->data))[inum % IPB]; 123e8d11c2eSkaashoek if (dip->type == 0) { // a free inode 124e8d11c2eSkaashoek break; 125e8d11c2eSkaashoek } 126e8d11c2eSkaashoek brelse(bp); 127e8d11c2eSkaashoek } 128e8d11c2eSkaashoek 129e8d11c2eSkaashoek if (inum >= ninodes) { 130*24111398Skaashoek panic ("ialloc: no inodes left\n"); 131e8d11c2eSkaashoek } 132e8d11c2eSkaashoek 133e8d11c2eSkaashoek cprintf ("ialloc: %d\n", inum); 134e8d11c2eSkaashoek dip->type = type; 135*24111398Skaashoek bwrite (dev, bp, IBLOCK(inum)); // mark it allocated on the disk 136e8d11c2eSkaashoek brelse(bp); 137e8d11c2eSkaashoek ip = iget (dev, inum); 138e8d11c2eSkaashoek return ip; 139e8d11c2eSkaashoek } 140e8d11c2eSkaashoek 141e8d11c2eSkaashoek void 142e8d11c2eSkaashoek iupdate (struct inode *ip) 143e8d11c2eSkaashoek { 144e8d11c2eSkaashoek struct buf *bp; 145e8d11c2eSkaashoek struct dinode *dip; 146e8d11c2eSkaashoek 147*24111398Skaashoek bp = bread(ip->dev, IBLOCK(ip->inum)); 148e8d11c2eSkaashoek dip = &((struct dinode *)(bp->data))[ip->inum % IPB]; 149e8d11c2eSkaashoek dip->type = ip->type; 150e8d11c2eSkaashoek dip->major = ip->major; 151e8d11c2eSkaashoek dip->minor = ip->minor; 152e8d11c2eSkaashoek dip->nlink = ip->nlink; 153e8d11c2eSkaashoek dip->size = ip->size; 154*24111398Skaashoek bwrite (ip->dev, bp, IBLOCK(ip->inum)); // mark it allocated on the disk 155e8d11c2eSkaashoek brelse(bp); 156e8d11c2eSkaashoek } 157e8d11c2eSkaashoek 15811a9947fSrtm void 1599d3fb671Srtm ilock(struct inode *ip) 1609d3fb671Srtm { 1619d3fb671Srtm if(ip->count < 1) 1629d3fb671Srtm panic("ilock"); 1639d3fb671Srtm 1649d3fb671Srtm acquire(&inode_table_lock); 1659d3fb671Srtm 1669d3fb671Srtm while(ip->busy) 1679d3fb671Srtm sleep(ip, &inode_table_lock); 1689d3fb671Srtm ip->busy = 1; 1699d3fb671Srtm 1709d3fb671Srtm release(&inode_table_lock); 1719d3fb671Srtm } 1729d3fb671Srtm 1739d3fb671Srtm // caller is holding onto a reference to this inode, but no 1749d3fb671Srtm // longer needs to examine or change it, so clear ip->busy. 1759d3fb671Srtm void 1769d3fb671Srtm iunlock(struct inode *ip) 1779d3fb671Srtm { 1789d3fb671Srtm if(ip->busy != 1) 1799d3fb671Srtm panic("iunlock"); 1809d3fb671Srtm 1819d3fb671Srtm acquire(&inode_table_lock); 1829d3fb671Srtm 1839d3fb671Srtm ip->busy = 0; 1849d3fb671Srtm wakeup(ip); 1859d3fb671Srtm 1869d3fb671Srtm release(&inode_table_lock); 1879d3fb671Srtm } 1889d3fb671Srtm 1899d3fb671Srtm // caller is releasing a reference to this inode. 1909d3fb671Srtm // you must have the inode lock. 1919d3fb671Srtm void 19211a9947fSrtm iput(struct inode *ip) 19311a9947fSrtm { 1949d3fb671Srtm if(ip->count < 1 || ip->busy != 1) 1959d3fb671Srtm panic("iput"); 1969d3fb671Srtm 19711a9947fSrtm acquire(&inode_table_lock); 19811a9947fSrtm 19911a9947fSrtm ip->count -= 1; 20011a9947fSrtm ip->busy = 0; 20111a9947fSrtm wakeup(ip); 20211a9947fSrtm 20311a9947fSrtm release(&inode_table_lock); 20411a9947fSrtm } 2059d3fb671Srtm 2069d3fb671Srtm void 20732630628Srtm idecref(struct inode *ip) 2089d3fb671Srtm { 2099d3fb671Srtm acquire(&inode_table_lock); 2109d3fb671Srtm 21132630628Srtm if(ip->count < 1) 21232630628Srtm panic("idecref"); 21332630628Srtm 21432630628Srtm ip->count -= 1; 2159d3fb671Srtm 2169d3fb671Srtm release(&inode_table_lock); 2179d3fb671Srtm } 2189d3fb671Srtm 2199d3fb671Srtm uint 2209d3fb671Srtm bmap(struct inode *ip, uint bn) 2219d3fb671Srtm { 2229d3fb671Srtm unsigned x; 2239d3fb671Srtm 2249d3fb671Srtm if(bn >= NDIRECT) 2259d3fb671Srtm panic("bmap 1"); 2269d3fb671Srtm x = ip->addrs[bn]; 2279d3fb671Srtm if(x == 0) 2289d3fb671Srtm panic("bmap 2"); 2299d3fb671Srtm return x; 2309d3fb671Srtm } 2319d3fb671Srtm 232c59361f1Srtm #define min(a, b) ((a) < (b) ? (a) : (b)) 233c59361f1Srtm 234c59361f1Srtm int 235c59361f1Srtm readi(struct inode *ip, void *xdst, uint off, uint n) 236c59361f1Srtm { 237c59361f1Srtm char *dst = (char *) xdst; 238c59361f1Srtm uint target = n, n1; 239c59361f1Srtm struct buf *bp; 240c59361f1Srtm 241c59361f1Srtm while(n > 0 && off < ip->size){ 242*24111398Skaashoek bp = bread(ip->dev, bmap(ip, off / BSIZE)); 243c59361f1Srtm n1 = min(n, ip->size - off); 244*24111398Skaashoek n1 = min(n1, BSIZE - (off % BSIZE)); 245*24111398Skaashoek memmove(dst, bp->data + (off % BSIZE), n1); 246c59361f1Srtm n -= n1; 247c59361f1Srtm off += n1; 248c59361f1Srtm dst += n1; 249c59361f1Srtm brelse(bp); 250c59361f1Srtm } 251c59361f1Srtm 252c59361f1Srtm return target - n; 253c59361f1Srtm } 254c59361f1Srtm 2559d3fb671Srtm struct inode * 2569d3fb671Srtm namei(char *path) 2579d3fb671Srtm { 2589d3fb671Srtm struct inode *dp; 2599d3fb671Srtm char *cp = path; 2609d3fb671Srtm uint off, dev; 2619d3fb671Srtm struct buf *bp; 2629d3fb671Srtm struct dirent *ep; 2639d3fb671Srtm int i; 2649d3fb671Srtm unsigned ninum; 2659d3fb671Srtm 2669d3fb671Srtm dp = iget(rootdev, 1); 2679d3fb671Srtm 2689d3fb671Srtm while(*cp == '/') 2699d3fb671Srtm cp++; 2709d3fb671Srtm 2719d3fb671Srtm while(1){ 2729d3fb671Srtm if(*cp == '\0') 2739d3fb671Srtm return dp; 2749d3fb671Srtm 2759d3fb671Srtm if(dp->type != T_DIR){ 2769d3fb671Srtm iput(dp); 2779d3fb671Srtm return 0; 2789d3fb671Srtm } 2799d3fb671Srtm 280*24111398Skaashoek for(off = 0; off < dp->size; off += BSIZE){ 281*24111398Skaashoek bp = bread(dp->dev, bmap(dp, off / BSIZE)); 2829d3fb671Srtm for(ep = (struct dirent *) bp->data; 283*24111398Skaashoek ep < (struct dirent *) (bp->data + BSIZE); 2849d3fb671Srtm ep++){ 2859d3fb671Srtm if(ep->inum == 0) 2869d3fb671Srtm continue; 2879d3fb671Srtm for(i = 0; i < DIRSIZ && cp[i] != '/' && cp[i]; i++) 2889d3fb671Srtm if(cp[i] != ep->name[i]) 2899d3fb671Srtm break; 2909d3fb671Srtm if((cp[i] == '\0' || cp[i] == '/') && (i >= DIRSIZ || ep->name[i] == '\0')){ 2919d3fb671Srtm ninum = ep->inum; 2929d3fb671Srtm brelse(bp); 2939d3fb671Srtm cp += i; 2949d3fb671Srtm goto found; 2959d3fb671Srtm } 2969d3fb671Srtm } 2979d3fb671Srtm brelse(bp); 2989d3fb671Srtm } 2999d3fb671Srtm iput(dp); 3009d3fb671Srtm return 0; 3019d3fb671Srtm 3029d3fb671Srtm found: 3039d3fb671Srtm dev = dp->dev; 3049d3fb671Srtm iput(dp); 3059d3fb671Srtm dp = iget(dev, ninum); 3069d3fb671Srtm while(*cp == '/') 3079d3fb671Srtm cp++; 3089d3fb671Srtm } 3099d3fb671Srtm } 310e8d11c2eSkaashoek 311e8d11c2eSkaashoek struct inode * 312e8d11c2eSkaashoek mknod(struct inode *dp, char *cp, short type, short major, short minor) 313e8d11c2eSkaashoek { 314e8d11c2eSkaashoek struct inode *ip; 315e8d11c2eSkaashoek struct dirent *ep = 0; 316e8d11c2eSkaashoek int off; 317e8d11c2eSkaashoek int i; 318e8d11c2eSkaashoek struct buf *bp = 0; 319e8d11c2eSkaashoek 320e8d11c2eSkaashoek cprintf("mknod: %s %d %d %d\n", cp, type, major, minor); 321e8d11c2eSkaashoek 322e8d11c2eSkaashoek ip = ialloc(dp->dev, type); 323e8d11c2eSkaashoek if (ip == 0) return 0; 324e8d11c2eSkaashoek ip->major = major; 325e8d11c2eSkaashoek ip->minor = minor; 326e8d11c2eSkaashoek 327*24111398Skaashoek for(off = 0; off < dp->size; off += BSIZE) { 328*24111398Skaashoek bp = bread(dp->dev, bmap(dp, off / BSIZE)); 329e8d11c2eSkaashoek for(ep = (struct dirent *) bp->data; 330*24111398Skaashoek ep < (struct dirent *) (bp->data + BSIZE); 331e8d11c2eSkaashoek ep++){ 332e8d11c2eSkaashoek if(ep->inum == 0) { 333e8d11c2eSkaashoek goto found; 334e8d11c2eSkaashoek } 335e8d11c2eSkaashoek } 336e8d11c2eSkaashoek brelse(bp); 337e8d11c2eSkaashoek } 338e8d11c2eSkaashoek panic("mknod: no dir entry free\n"); 339e8d11c2eSkaashoek 340e8d11c2eSkaashoek found: 341e8d11c2eSkaashoek ep->inum = ip->inum; 342e8d11c2eSkaashoek for(i = 0; i < DIRSIZ && cp[i]; i++) ep->name[i] = cp[i]; 343*24111398Skaashoek bwrite (dp->dev, bp, bmap(dp, off/BSIZE)); // write directory 344e8d11c2eSkaashoek brelse(bp); 345e8d11c2eSkaashoek iupdate (ip); 346e8d11c2eSkaashoek return ip; 347e8d11c2eSkaashoek } 348