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" 116fa5ffb5Skaashoek #include "dev.h" 1211a9947fSrtm 1311a9947fSrtm // these are inodes currently in use 1411a9947fSrtm // an entry is free if count == 0 1511a9947fSrtm struct inode inode[NINODE]; 16*5be0039cSrtm struct spinlock inode_table_lock; 1711a9947fSrtm 189d3fb671Srtm uint rootdev = 1; 199d3fb671Srtm 20*5be0039cSrtm void 21*5be0039cSrtm iinit(void) 22*5be0039cSrtm { 23*5be0039cSrtm initlock(&inode_table_lock, "inode_table"); 24*5be0039cSrtm } 25*5be0039cSrtm 2624111398Skaashoek static uint 2724111398Skaashoek balloc(uint dev) 2824111398Skaashoek { 2924111398Skaashoek int b; 3024111398Skaashoek struct buf *bp; 3124111398Skaashoek struct superblock *sb; 3228d9ef04Skaashoek int bi = 0; 3324111398Skaashoek int size; 3424111398Skaashoek int ninodes; 3524111398Skaashoek uchar m; 3624111398Skaashoek 3724111398Skaashoek bp = bread(dev, 1); 3824111398Skaashoek sb = (struct superblock *) bp->data; 3924111398Skaashoek size = sb->size; 4024111398Skaashoek ninodes = sb->ninodes; 4124111398Skaashoek 4224111398Skaashoek for (b = 0; b < size; b++) { 4324111398Skaashoek if (b % BPB == 0) { 4424111398Skaashoek brelse(bp); 4524111398Skaashoek bp = bread(dev, BBLOCK(b, ninodes)); 4624111398Skaashoek } 4724111398Skaashoek bi = b % BPB; 4824111398Skaashoek m = 0x1 << (bi % 8); 4924111398Skaashoek if ((bp->data[bi/8] & m) == 0) { // is block free? 5024111398Skaashoek break; 5124111398Skaashoek } 5224111398Skaashoek } 5324111398Skaashoek if (b >= size) 5424111398Skaashoek panic("balloc: out of blocks\n"); 5524111398Skaashoek 5624111398Skaashoek cprintf ("balloc: allocate block %d\n", b); 5724111398Skaashoek bp->data[bi/8] |= 0x1 << (bi % 8); 5824111398Skaashoek bwrite (dev, bp, BBLOCK(b, ninodes)); // mark it allocated on disk 5928d9ef04Skaashoek brelse(bp); 6024111398Skaashoek return b; 6124111398Skaashoek } 6224111398Skaashoek 6328d9ef04Skaashoek static void 6428d9ef04Skaashoek bfree(int dev, uint b) 6528d9ef04Skaashoek { 6628d9ef04Skaashoek struct buf *bp; 6728d9ef04Skaashoek struct superblock *sb; 6828d9ef04Skaashoek int bi; 6928d9ef04Skaashoek int ninodes; 7028d9ef04Skaashoek uchar m; 7128d9ef04Skaashoek 7228d9ef04Skaashoek cprintf ("bfree: free block %d\n", b); 7328d9ef04Skaashoek bp = bread(dev, 1); 7428d9ef04Skaashoek sb = (struct superblock *) bp->data; 7528d9ef04Skaashoek ninodes = sb->ninodes; 7628d9ef04Skaashoek brelse(bp); 7728d9ef04Skaashoek 7828d9ef04Skaashoek bp = bread(dev, BBLOCK(b, ninodes)); 7928d9ef04Skaashoek bi = b % BPB; 8028d9ef04Skaashoek m = ~(0x1 << (bi %8)); 8128d9ef04Skaashoek bp->data[bi/8] &= m; 8228d9ef04Skaashoek bwrite (dev, bp, BBLOCK(b, ninodes)); // mark it free on disk 8328d9ef04Skaashoek brelse(bp); 8428d9ef04Skaashoek } 8524111398Skaashoek 869d3fb671Srtm // returns an inode with busy set and incremented reference count. 8711a9947fSrtm struct inode * 8811a9947fSrtm iget(uint dev, uint inum) 8911a9947fSrtm { 9011a9947fSrtm struct inode *ip, *nip = 0; 9111a9947fSrtm struct dinode *dip; 9211a9947fSrtm struct buf *bp; 9311a9947fSrtm 9411a9947fSrtm acquire(&inode_table_lock); 9511a9947fSrtm 9611a9947fSrtm loop: 9711a9947fSrtm for(ip = &inode[0]; ip < &inode[NINODE]; ip++){ 9811a9947fSrtm if(ip->count > 0 && ip->dev == dev && ip->inum == inum){ 9911a9947fSrtm if(ip->busy){ 10011a9947fSrtm sleep(ip, &inode_table_lock); 10111a9947fSrtm goto loop; 10211a9947fSrtm } 10311a9947fSrtm ip->count++; 10411a9947fSrtm release(&inode_table_lock); 10511a9947fSrtm return ip; 10611a9947fSrtm } 10711a9947fSrtm if(nip == 0 && ip->count == 0) 10811a9947fSrtm nip = ip; 10911a9947fSrtm } 11011a9947fSrtm 11111a9947fSrtm if(nip == 0) 11211a9947fSrtm panic("out of inodes"); 11311a9947fSrtm 11411a9947fSrtm nip->dev = dev; 11511a9947fSrtm nip->inum = inum; 11611a9947fSrtm nip->count = 1; 11711a9947fSrtm nip->busy = 1; 11811a9947fSrtm 11911a9947fSrtm release(&inode_table_lock); 12011a9947fSrtm 12124111398Skaashoek bp = bread(dev, IBLOCK(inum)); 12211a9947fSrtm dip = &((struct dinode *)(bp->data))[inum % IPB]; 12311a9947fSrtm nip->type = dip->type; 124e8d11c2eSkaashoek nip->major = dip->major; 125e8d11c2eSkaashoek nip->minor = dip->minor; 12611a9947fSrtm nip->nlink = dip->nlink; 12711a9947fSrtm nip->size = dip->size; 12811a9947fSrtm memmove(nip->addrs, dip->addrs, sizeof(nip->addrs)); 12911a9947fSrtm brelse(bp); 13011a9947fSrtm 13111a9947fSrtm return nip; 13211a9947fSrtm } 13311a9947fSrtm 13428d9ef04Skaashoek void 13528d9ef04Skaashoek iupdate (struct inode *ip) 13628d9ef04Skaashoek { 13728d9ef04Skaashoek struct buf *bp; 13828d9ef04Skaashoek struct dinode *dip; 13928d9ef04Skaashoek 14028d9ef04Skaashoek bp = bread(ip->dev, IBLOCK(ip->inum)); 14128d9ef04Skaashoek dip = &((struct dinode *)(bp->data))[ip->inum % IPB]; 14228d9ef04Skaashoek dip->type = ip->type; 14328d9ef04Skaashoek dip->major = ip->major; 14428d9ef04Skaashoek dip->minor = ip->minor; 14528d9ef04Skaashoek dip->nlink = ip->nlink; 14628d9ef04Skaashoek dip->size = ip->size; 14728d9ef04Skaashoek memmove(dip->addrs, ip->addrs, sizeof(ip->addrs)); 14828d9ef04Skaashoek bwrite (ip->dev, bp, IBLOCK(ip->inum)); // mark it allocated on the disk 14928d9ef04Skaashoek brelse(bp); 15028d9ef04Skaashoek } 15128d9ef04Skaashoek 152e8d11c2eSkaashoek struct inode * 153e8d11c2eSkaashoek ialloc(uint dev, short type) 154e8d11c2eSkaashoek { 155e8d11c2eSkaashoek struct inode *ip; 156e8d11c2eSkaashoek struct dinode *dip = 0; 157e8d11c2eSkaashoek struct superblock *sb; 158e8d11c2eSkaashoek int ninodes; 159e8d11c2eSkaashoek int inum; 160e8d11c2eSkaashoek struct buf *bp; 161e8d11c2eSkaashoek 162e8d11c2eSkaashoek bp = bread(dev, 1); 16324111398Skaashoek sb = (struct superblock *) bp->data; 164e8d11c2eSkaashoek ninodes = sb->ninodes; 165e8d11c2eSkaashoek brelse(bp); 166e8d11c2eSkaashoek 167e8d11c2eSkaashoek for (inum = 1; inum < ninodes; inum++) { // loop over inode blocks 16824111398Skaashoek bp = bread(dev, IBLOCK(inum)); 169e8d11c2eSkaashoek dip = &((struct dinode *)(bp->data))[inum % IPB]; 170e8d11c2eSkaashoek if (dip->type == 0) { // a free inode 171e8d11c2eSkaashoek break; 172e8d11c2eSkaashoek } 173e8d11c2eSkaashoek brelse(bp); 174e8d11c2eSkaashoek } 175e8d11c2eSkaashoek 176e8d11c2eSkaashoek if (inum >= ninodes) { 17724111398Skaashoek panic ("ialloc: no inodes left\n"); 178e8d11c2eSkaashoek } 179e8d11c2eSkaashoek 180e8d11c2eSkaashoek cprintf ("ialloc: %d\n", inum); 181e8d11c2eSkaashoek dip->type = type; 18224111398Skaashoek bwrite (dev, bp, IBLOCK(inum)); // mark it allocated on the disk 183e8d11c2eSkaashoek brelse(bp); 184e8d11c2eSkaashoek ip = iget (dev, inum); 185e8d11c2eSkaashoek return ip; 186e8d11c2eSkaashoek } 187e8d11c2eSkaashoek 18828d9ef04Skaashoek static void 18928d9ef04Skaashoek ifree(uint dev, struct inode *ip) 190e8d11c2eSkaashoek { 19128d9ef04Skaashoek ip->type = 0; 19228d9ef04Skaashoek iupdate(ip); 193e8d11c2eSkaashoek } 194e8d11c2eSkaashoek 19511a9947fSrtm void 1969d3fb671Srtm ilock(struct inode *ip) 1979d3fb671Srtm { 1989d3fb671Srtm if(ip->count < 1) 1999d3fb671Srtm panic("ilock"); 2009d3fb671Srtm 2019d3fb671Srtm acquire(&inode_table_lock); 2029d3fb671Srtm 2039d3fb671Srtm while(ip->busy) 2049d3fb671Srtm sleep(ip, &inode_table_lock); 2059d3fb671Srtm ip->busy = 1; 2069d3fb671Srtm 2079d3fb671Srtm release(&inode_table_lock); 2089d3fb671Srtm } 2099d3fb671Srtm 2109d3fb671Srtm // caller is holding onto a reference to this inode, but no 2119d3fb671Srtm // longer needs to examine or change it, so clear ip->busy. 2129d3fb671Srtm void 2139d3fb671Srtm iunlock(struct inode *ip) 2149d3fb671Srtm { 2159d3fb671Srtm if(ip->busy != 1) 2169d3fb671Srtm panic("iunlock"); 2179d3fb671Srtm 2189d3fb671Srtm acquire(&inode_table_lock); 2199d3fb671Srtm 2209d3fb671Srtm ip->busy = 0; 2219d3fb671Srtm wakeup(ip); 2229d3fb671Srtm 2239d3fb671Srtm release(&inode_table_lock); 2249d3fb671Srtm } 2259d3fb671Srtm 2269d3fb671Srtm // caller is releasing a reference to this inode. 2279d3fb671Srtm // you must have the inode lock. 2289d3fb671Srtm void 22911a9947fSrtm iput(struct inode *ip) 23011a9947fSrtm { 2319d3fb671Srtm if(ip->count < 1 || ip->busy != 1) 2329d3fb671Srtm panic("iput"); 2339d3fb671Srtm 23411a9947fSrtm acquire(&inode_table_lock); 23511a9947fSrtm 23611a9947fSrtm ip->count -= 1; 23711a9947fSrtm ip->busy = 0; 23811a9947fSrtm wakeup(ip); 23911a9947fSrtm 24011a9947fSrtm release(&inode_table_lock); 24111a9947fSrtm } 2429d3fb671Srtm 2439d3fb671Srtm void 24432630628Srtm idecref(struct inode *ip) 2459d3fb671Srtm { 2469d3fb671Srtm acquire(&inode_table_lock); 2479d3fb671Srtm 24832630628Srtm if(ip->count < 1) 24932630628Srtm panic("idecref"); 25032630628Srtm 25132630628Srtm ip->count -= 1; 2529d3fb671Srtm 2539d3fb671Srtm release(&inode_table_lock); 2549d3fb671Srtm } 2559d3fb671Srtm 2569d3fb671Srtm uint 2579d3fb671Srtm bmap(struct inode *ip, uint bn) 2589d3fb671Srtm { 2599d3fb671Srtm unsigned x; 2609d3fb671Srtm 2619d3fb671Srtm if(bn >= NDIRECT) 2629d3fb671Srtm panic("bmap 1"); 2639d3fb671Srtm x = ip->addrs[bn]; 2649d3fb671Srtm if(x == 0) 2659d3fb671Srtm panic("bmap 2"); 2669d3fb671Srtm return x; 2679d3fb671Srtm } 2689d3fb671Srtm 269c59361f1Srtm #define min(a, b) ((a) < (b) ? (a) : (b)) 270c59361f1Srtm 271c59361f1Srtm int 272c59361f1Srtm readi(struct inode *ip, void *xdst, uint off, uint n) 273c59361f1Srtm { 274c59361f1Srtm char *dst = (char *) xdst; 275c59361f1Srtm uint target = n, n1; 276c59361f1Srtm struct buf *bp; 277c59361f1Srtm 278939f9edeSkaashoek if (ip->type == T_DEV) { 279939f9edeSkaashoek if (ip->major < 0 || ip->major >= NDEV || !devsw[ip->major].d_read) 280939f9edeSkaashoek return -1; 281939f9edeSkaashoek return devsw[ip->major].d_read (ip->minor, xdst, n); 282939f9edeSkaashoek } 283939f9edeSkaashoek 284c59361f1Srtm while(n > 0 && off < ip->size){ 28524111398Skaashoek bp = bread(ip->dev, bmap(ip, off / BSIZE)); 286c59361f1Srtm n1 = min(n, ip->size - off); 28724111398Skaashoek n1 = min(n1, BSIZE - (off % BSIZE)); 28824111398Skaashoek memmove(dst, bp->data + (off % BSIZE), n1); 289c59361f1Srtm n -= n1; 290c59361f1Srtm off += n1; 291c59361f1Srtm dst += n1; 292c59361f1Srtm brelse(bp); 293c59361f1Srtm } 294c59361f1Srtm 295c59361f1Srtm return target - n; 296c59361f1Srtm } 297c59361f1Srtm 29828d9ef04Skaashoek #define MIN(a, b) ((a < b) ? a : b) 29928d9ef04Skaashoek 3006fa5ffb5Skaashoek int 30128d9ef04Skaashoek writei(struct inode *ip, void *addr, uint off, uint n) 3026fa5ffb5Skaashoek { 3036fa5ffb5Skaashoek if (ip->type == T_DEV) { 304939f9edeSkaashoek if (ip->major < 0 || ip->major >= NDEV || !devsw[ip->major].d_write) 305939f9edeSkaashoek return -1; 3066fa5ffb5Skaashoek return devsw[ip->major].d_write (ip->minor, addr, n); 30728d9ef04Skaashoek } else if (ip->type == T_FILE || ip->type == T_DIR) { // XXX dir here too? 30828d9ef04Skaashoek struct buf *bp; 30928d9ef04Skaashoek int r = 0; 31028d9ef04Skaashoek int m; 31128d9ef04Skaashoek int lbn; 31228d9ef04Skaashoek uint b; 31328d9ef04Skaashoek while (r < n) { 31428d9ef04Skaashoek lbn = off / BSIZE; 31528d9ef04Skaashoek if (lbn >= NDIRECT) return r; 31628d9ef04Skaashoek if (ip->addrs[lbn] == 0) { 31728d9ef04Skaashoek b = balloc(ip->dev); 31828d9ef04Skaashoek if (b <= 0) return r; 31928d9ef04Skaashoek ip->addrs[lbn] = b; 32028d9ef04Skaashoek } 32128d9ef04Skaashoek m = MIN(BSIZE - off % BSIZE, n-r); 32228d9ef04Skaashoek bp = bread(ip->dev, bmap(ip, off / BSIZE)); 32328d9ef04Skaashoek memmove (bp->data + off % BSIZE, addr, m); 32428d9ef04Skaashoek bwrite (ip->dev, bp, bmap(ip, off/BSIZE)); 32528d9ef04Skaashoek brelse (bp); 32628d9ef04Skaashoek r += m; 32728d9ef04Skaashoek off += m; 32828d9ef04Skaashoek } 32928d9ef04Skaashoek if (r > 0) { 33028d9ef04Skaashoek if (off > ip->size) { 33128d9ef04Skaashoek ip->size = off; 33228d9ef04Skaashoek } 33328d9ef04Skaashoek iupdate(ip); 33428d9ef04Skaashoek } 33528d9ef04Skaashoek return r; 3366fa5ffb5Skaashoek } else { 3376fa5ffb5Skaashoek panic ("writei: unknown type\n"); 3388a8be1b8Srtm return 0; 3396fa5ffb5Skaashoek } 3406fa5ffb5Skaashoek } 3416fa5ffb5Skaashoek 3429d3fb671Srtm struct inode * 3439d3fb671Srtm namei(char *path) 3449d3fb671Srtm { 3459d3fb671Srtm struct inode *dp; 3469d3fb671Srtm char *cp = path; 3479d3fb671Srtm uint off, dev; 3489d3fb671Srtm struct buf *bp; 3499d3fb671Srtm struct dirent *ep; 3509d3fb671Srtm int i; 3519d3fb671Srtm unsigned ninum; 3529d3fb671Srtm 3539d3fb671Srtm dp = iget(rootdev, 1); 3549d3fb671Srtm 3559d3fb671Srtm while(*cp == '/') 3569d3fb671Srtm cp++; 3579d3fb671Srtm 3589d3fb671Srtm while(1){ 3599d3fb671Srtm if(*cp == '\0') 3609d3fb671Srtm return dp; 3619d3fb671Srtm 3629d3fb671Srtm if(dp->type != T_DIR){ 3639d3fb671Srtm iput(dp); 3649d3fb671Srtm return 0; 3659d3fb671Srtm } 3669d3fb671Srtm 36724111398Skaashoek for(off = 0; off < dp->size; off += BSIZE){ 36824111398Skaashoek bp = bread(dp->dev, bmap(dp, off / BSIZE)); 3699d3fb671Srtm for(ep = (struct dirent *) bp->data; 37024111398Skaashoek ep < (struct dirent *) (bp->data + BSIZE); 3719d3fb671Srtm ep++){ 3729d3fb671Srtm if(ep->inum == 0) 3739d3fb671Srtm continue; 3749d3fb671Srtm for(i = 0; i < DIRSIZ && cp[i] != '/' && cp[i]; i++) 3759d3fb671Srtm if(cp[i] != ep->name[i]) 3769d3fb671Srtm break; 3779d3fb671Srtm if((cp[i] == '\0' || cp[i] == '/') && (i >= DIRSIZ || ep->name[i] == '\0')){ 3789d3fb671Srtm ninum = ep->inum; 3799d3fb671Srtm brelse(bp); 3809d3fb671Srtm cp += i; 3819d3fb671Srtm goto found; 3829d3fb671Srtm } 3839d3fb671Srtm } 3849d3fb671Srtm brelse(bp); 3859d3fb671Srtm } 3869d3fb671Srtm iput(dp); 3879d3fb671Srtm return 0; 3889d3fb671Srtm 3899d3fb671Srtm found: 3909d3fb671Srtm dev = dp->dev; 3919d3fb671Srtm iput(dp); 3929d3fb671Srtm dp = iget(dev, ninum); 3939d3fb671Srtm while(*cp == '/') 3949d3fb671Srtm cp++; 3959d3fb671Srtm } 3969d3fb671Srtm } 397e8d11c2eSkaashoek 398e8d11c2eSkaashoek struct inode * 399e8d11c2eSkaashoek mknod(struct inode *dp, char *cp, short type, short major, short minor) 400e8d11c2eSkaashoek { 401e8d11c2eSkaashoek struct inode *ip; 402e8d11c2eSkaashoek struct dirent *ep = 0; 403e8d11c2eSkaashoek int off; 404e8d11c2eSkaashoek int i; 405e8d11c2eSkaashoek struct buf *bp = 0; 406e8d11c2eSkaashoek 407e8d11c2eSkaashoek cprintf("mknod: %s %d %d %d\n", cp, type, major, minor); 408e8d11c2eSkaashoek 409e8d11c2eSkaashoek ip = ialloc(dp->dev, type); 410e8d11c2eSkaashoek if (ip == 0) return 0; 411e8d11c2eSkaashoek ip->major = major; 412e8d11c2eSkaashoek ip->minor = minor; 4136c0e444fSkaashoek ip->size = 0; 4146c0e444fSkaashoek ip->nlink = 0; 4156c0e444fSkaashoek 4166c0e444fSkaashoek iupdate (ip); // write new inode to disk 417e8d11c2eSkaashoek 41824111398Skaashoek for(off = 0; off < dp->size; off += BSIZE) { 41924111398Skaashoek bp = bread(dp->dev, bmap(dp, off / BSIZE)); 420e8d11c2eSkaashoek for(ep = (struct dirent *) bp->data; 42124111398Skaashoek ep < (struct dirent *) (bp->data + BSIZE); 422e8d11c2eSkaashoek ep++){ 423e8d11c2eSkaashoek if(ep->inum == 0) { 424e8d11c2eSkaashoek goto found; 425e8d11c2eSkaashoek } 426e8d11c2eSkaashoek } 427e8d11c2eSkaashoek brelse(bp); 428e8d11c2eSkaashoek } 42928d9ef04Skaashoek panic("mknod: XXXX no dir entry free\n"); 430e8d11c2eSkaashoek 431e8d11c2eSkaashoek found: 432e8d11c2eSkaashoek ep->inum = ip->inum; 433e8d11c2eSkaashoek for(i = 0; i < DIRSIZ && cp[i]; i++) ep->name[i] = cp[i]; 4346c0e444fSkaashoek bwrite (dp->dev, bp, bmap(dp, off/BSIZE)); // write directory block 435e8d11c2eSkaashoek brelse(bp); 4366c0e444fSkaashoek 4376c0e444fSkaashoek dp->size += sizeof(struct dirent); // update directory inode 4386c0e444fSkaashoek iupdate (dp); 4396c0e444fSkaashoek 440e8d11c2eSkaashoek return ip; 441e8d11c2eSkaashoek } 442