From c24ac5d76353d04955cc348f1cb5b95743c42b38 Mon Sep 17 00:00:00 2001 From: Frans Kaashoek Date: Fri, 3 Apr 2015 08:22:02 -0400 Subject: [PATCH] Disentangle block size from the disk's sector size. Set block size to 1024 to show that they can be different. Clean up mkfs, simplifying specifying fs parameters, remove some redundancy between fs and mkfs, and fix disk layout bugs. Call blocks in the file system blocks instead of sectors. Passes usertests for different block sizes. --- bio.c | 20 ++++++------ bootmain.c | 2 +- buf.h | 4 +-- fs.c | 2 +- fs.h | 2 +- ide.c | 20 ++++++++---- kill.c | 2 +- log.c | 18 +++++------ memide.c | 12 +++---- mkfs.c | 93 ++++++++++++++++++++++++++---------------------------- param.h | 2 +- 11 files changed, 91 insertions(+), 86 deletions(-) diff --git a/bio.c b/bio.c index 6a28053ea6..629bb2c52c 100644 --- a/bio.c +++ b/bio.c @@ -24,6 +24,7 @@ #include "defs.h" #include "param.h" #include "spinlock.h" +#include "fs.h" #include "buf.h" struct { @@ -55,20 +56,20 @@ binit(void) } } -// Look through buffer cache for sector on device dev. +// Look through buffer cache for block on device dev. // If not found, allocate a buffer. // In either case, return B_BUSY buffer. static struct buf* -bget(uint dev, uint sector) +bget(uint dev, uint blockno) { struct buf *b; acquire(&bcache.lock); loop: - // Is the sector already cached? + // Is the block already cached? for(b = bcache.head.next; b != &bcache.head; b = b->next){ - if(b->dev == dev && b->sector == sector){ + if(b->dev == dev && b->blockno == blockno){ if(!(b->flags & B_BUSY)){ b->flags |= B_BUSY; release(&bcache.lock); @@ -85,7 +86,7 @@ bget(uint dev, uint sector) for(b = bcache.head.prev; b != &bcache.head; b = b->prev){ if((b->flags & B_BUSY) == 0 && (b->flags & B_DIRTY) == 0){ b->dev = dev; - b->sector = sector; + b->blockno = blockno; b->flags = B_BUSY; release(&bcache.lock); return b; @@ -94,15 +95,16 @@ bget(uint dev, uint sector) panic("bget: no buffers"); } -// Return a B_BUSY buf with the contents of the indicated disk sector. +// Return a B_BUSY buf with the contents of the indicated block. struct buf* -bread(uint dev, uint sector) +bread(uint dev, uint blockno) { struct buf *b; - b = bget(dev, sector); - if(!(b->flags & B_VALID)) + b = bget(dev, blockno); + if(!(b->flags & B_VALID)) { iderw(b); + } return b; } diff --git a/bootmain.c b/bootmain.c index d24bf665e9..97d5258727 100644 --- a/bootmain.c +++ b/bootmain.c @@ -1,6 +1,6 @@ // Boot loader. // -// Part of the boot sector, along with bootasm.S, which calls bootmain(). +// Part of the boot block, along with bootasm.S, which calls bootmain(). // bootasm.S has put the processor into protected 32-bit mode. // bootmain() loads an ELF kernel image from the disk starting at // sector 1 and then jumps to the kernel entry routine. diff --git a/buf.h b/buf.h index 9c586f21d8..f18fd87686 100644 --- a/buf.h +++ b/buf.h @@ -1,11 +1,11 @@ struct buf { int flags; uint dev; - uint sector; + uint blockno; struct buf *prev; // LRU cache list struct buf *next; struct buf *qnext; // disk queue - uchar data[512]; + uchar data[BSIZE]; }; #define B_BUSY 0x1 // buffer is locked by some process #define B_VALID 0x2 // buffer has been read from disk diff --git a/fs.c b/fs.c index 1803cb489d..286252d994 100644 --- a/fs.c +++ b/fs.c @@ -16,8 +16,8 @@ #include "mmu.h" #include "proc.h" #include "spinlock.h" -#include "buf.h" #include "fs.h" +#include "buf.h" #include "file.h" #define min(a, b) ((a) < (b) ? (a) : (b)) diff --git a/fs.h b/fs.h index f191d43a66..e74ff5baea 100644 --- a/fs.h +++ b/fs.h @@ -9,7 +9,7 @@ // Then sb.nlog log blocks. #define ROOTINO 1 // root i-number -#define BSIZE 512 // block size +#define BSIZE 1024 // block size // File system super block struct superblock { diff --git a/ide.c b/ide.c index 6850a09105..96216ea17a 100644 --- a/ide.c +++ b/ide.c @@ -9,8 +9,10 @@ #include "x86.h" #include "traps.h" #include "spinlock.h" +#include "fs.h" #include "buf.h" +#define SECTOR_SIZE 512 #define IDE_BSY 0x80 #define IDE_DRDY 0x40 #define IDE_DF 0x20 @@ -71,17 +73,21 @@ idestart(struct buf *b) { if(b == 0) panic("idestart"); + int sector_per_block = BSIZE/SECTOR_SIZE; + int sector = b->blockno * sector_per_block; + if (sector_per_block > 7) panic("idestart"); + idewait(0); outb(0x3f6, 0); // generate interrupt - outb(0x1f2, 1); // number of sectors - outb(0x1f3, b->sector & 0xff); - outb(0x1f4, (b->sector >> 8) & 0xff); - outb(0x1f5, (b->sector >> 16) & 0xff); - outb(0x1f6, 0xe0 | ((b->dev&1)<<4) | ((b->sector>>24)&0x0f)); + outb(0x1f2, sector_per_block); // number of sectors + outb(0x1f3, sector & 0xff); + outb(0x1f4, (sector >> 8) & 0xff); + outb(0x1f5, (sector >> 16) & 0xff); + outb(0x1f6, 0xe0 | ((b->dev&1)<<4) | ((sector>>24)&0x0f)); if(b->flags & B_DIRTY){ outb(0x1f7, IDE_CMD_WRITE); - outsl(0x1f0, b->data, 512/4); + outsl(0x1f0, b->data, BSIZE/4); } else { outb(0x1f7, IDE_CMD_READ); } @@ -104,7 +110,7 @@ ideintr(void) // Read data if needed. if(!(b->flags & B_DIRTY) && idewait(1) >= 0) - insl(0x1f0, b->data, 512/4); + insl(0x1f0, b->data, BSIZE/4); // Wake process waiting for this buf. b->flags |= B_VALID; diff --git a/kill.c b/kill.c index 5e601135b5..364f6af2eb 100644 --- a/kill.c +++ b/kill.c @@ -7,7 +7,7 @@ main(int argc, char **argv) { int i; - if(argc < 1){ + if(argc < 2){ printf(2, "usage: kill pid...\n"); exit(); } diff --git a/log.c b/log.c index f519a8c27f..01aa580758 100644 --- a/log.c +++ b/log.c @@ -21,7 +21,7 @@ // // The log is a physical re-do log containing disk blocks. // The on-disk log format: -// header block, containing sector #s for block A, B, C, ... +// header block, containing block #s for block A, B, C, ... // block A // block B // block C @@ -29,10 +29,10 @@ // Log appends are synchronous. // Contents of the header block, used for both the on-disk header block -// and to keep track in memory of logged sector #s before commit. +// and to keep track in memory of logged block# before commit. struct logheader { int n; - int sector[LOGSIZE]; + int block[LOGSIZE]; }; struct log { @@ -72,7 +72,7 @@ install_trans(void) for (tail = 0; tail < log.lh.n; tail++) { struct buf *lbuf = bread(log.dev, log.start+tail+1); // read log block - struct buf *dbuf = bread(log.dev, log.lh.sector[tail]); // read dst + struct buf *dbuf = bread(log.dev, log.lh.block[tail]); // read dst memmove(dbuf->data, lbuf->data, BSIZE); // copy block to dst bwrite(dbuf); // write dst to disk brelse(lbuf); @@ -89,7 +89,7 @@ read_head(void) int i; log.lh.n = lh->n; for (i = 0; i < log.lh.n; i++) { - log.lh.sector[i] = lh->sector[i]; + log.lh.block[i] = lh->block[i]; } brelse(buf); } @@ -105,7 +105,7 @@ write_head(void) int i; hb->n = log.lh.n; for (i = 0; i < log.lh.n; i++) { - hb->sector[i] = log.lh.sector[i]; + hb->block[i] = log.lh.block[i]; } bwrite(buf); brelse(buf); @@ -178,7 +178,7 @@ write_log(void) for (tail = 0; tail < log.lh.n; tail++) { struct buf *to = bread(log.dev, log.start+tail+1); // log block - struct buf *from = bread(log.dev, log.lh.sector[tail]); // cache block + struct buf *from = bread(log.dev, log.lh.block[tail]); // cache block memmove(to->data, from->data, BSIZE); bwrite(to); // write the log brelse(from); @@ -219,10 +219,10 @@ log_write(struct buf *b) acquire(&log.lock); for (i = 0; i < log.lh.n; i++) { - if (log.lh.sector[i] == b->sector) // log absorbtion + if (log.lh.block[i] == b->blockno) // log absorbtion break; } - log.lh.sector[i] = b->sector; + log.lh.block[i] = b->blockno; if (i == log.lh.n) log.lh.n++; b->flags |= B_DIRTY; // prevent eviction diff --git a/memide.c b/memide.c index d2c5bb7e16..2e09e339cc 100644 --- a/memide.c +++ b/memide.c @@ -20,7 +20,7 @@ void ideinit(void) { memdisk = _binary_fs_img_start; - disksize = (uint)_binary_fs_img_size/512; + disksize = (uint)_binary_fs_img_size/BSIZE; } // Interrupt handler. @@ -44,15 +44,15 @@ iderw(struct buf *b) panic("iderw: nothing to do"); if(b->dev != 1) panic("iderw: request not for disk 1"); - if(b->sector >= disksize) - panic("iderw: sector out of range"); + if(b->block >= disksize) + panic("iderw: block out of range"); - p = memdisk + b->sector*512; + p = memdisk + b->block*BSIZE; if(b->flags & B_DIRTY){ b->flags &= ~B_DIRTY; - memmove(p, b->data, 512); + memmove(p, b->data, BSIZE); } else - memmove(b->data, p, 512); + memmove(b->data, p, BSIZE); b->flags |= B_VALID; } diff --git a/mkfs.c b/mkfs.c index c168377275..2d2859d432 100644 --- a/mkfs.c +++ b/mkfs.c @@ -13,18 +13,24 @@ #define static_assert(a, b) do { switch (0) case 0: case (a): ; } while (0) -int nblocks = (995-LOGSIZE); -int nlog = LOGSIZE; -int ninodes = 200; -int size = 1024; +#define SIZE 1000 +#define NINODES 200 + +// Disk layout: +// [ boot block | sb block | inode blocks | bit map | data blocks | log ] + +int nbitmap = SIZE/(BSIZE*8) + 1; +int ninodeblocks = NINODES / IPB + 1; +int nlog = LOGSIZE; +int nmeta; // Number of meta blocks (inode, bitmap, and 2 extra) +int nblocks; // Number of data blocks int fsfd; struct superblock sb; -char zeroes[512]; -uint freeblock; -uint usedblocks; -uint bitblocks; +char zeroes[BSIZE]; uint freeinode = 1; +uint freeblock; + void balloc(int); void wsect(uint, void*); @@ -63,7 +69,7 @@ main(int argc, char *argv[]) int i, cc, fd; uint rootino, inum, off; struct dirent de; - char buf[512]; + char buf[BSIZE]; struct dinode din; @@ -74,8 +80,8 @@ main(int argc, char *argv[]) exit(1); } - assert((512 % sizeof(struct dinode)) == 0); - assert((512 % sizeof(struct dirent)) == 0); + assert((BSIZE % sizeof(struct dinode)) == 0); + assert((BSIZE % sizeof(struct dirent)) == 0); fsfd = open(argv[1], O_RDWR|O_CREAT|O_TRUNC, 0666); if(fsfd < 0){ @@ -83,21 +89,19 @@ main(int argc, char *argv[]) exit(1); } - sb.size = xint(size); + nmeta = 2 + ninodeblocks + nbitmap; + nblocks = SIZE - nlog - nmeta; + + sb.size = xint(SIZE); sb.nblocks = xint(nblocks); // so whole disk is size sectors - sb.ninodes = xint(ninodes); + sb.ninodes = xint(NINODES); sb.nlog = xint(nlog); - bitblocks = size/(512*8) + 1; - usedblocks = ninodes / IPB + 3 + bitblocks; - freeblock = usedblocks; + printf("nmeta %d (boot, super, inode blocks %u, bitmap blocks %u) blocks %d log %u total %d\n", nmeta, ninodeblocks, nbitmap, nblocks, nlog, SIZE); - printf("used %d (bit %d ninode %zu) free %u log %u total %d\n", usedblocks, - bitblocks, ninodes/IPB + 1, freeblock, nlog, nblocks+usedblocks+nlog); + freeblock = nmeta; // the first free block that we can allocate - assert(nblocks + usedblocks + nlog == size); - - for(i = 0; i < nblocks + usedblocks + nlog; i++) + for(i = 0; i < SIZE; i++) wsect(i, zeroes); memset(buf, 0, sizeof(buf)); @@ -152,7 +156,7 @@ main(int argc, char *argv[]) din.size = xint(off); winode(rootino, &din); - balloc(usedblocks); + balloc(freeblock); exit(0); } @@ -160,30 +164,26 @@ main(int argc, char *argv[]) void wsect(uint sec, void *buf) { - if(lseek(fsfd, sec * 512L, 0) != sec * 512L){ + printf("seek to %d\n", sec * BSIZE); + if(lseek(fsfd, sec * BSIZE, 0) != sec * BSIZE){ perror("lseek"); exit(1); } - if(write(fsfd, buf, 512) != 512){ + if(write(fsfd, buf, BSIZE) != BSIZE){ perror("write"); exit(1); } } -uint -i2b(uint inum) -{ - return (inum / IPB) + 2; -} - void winode(uint inum, struct dinode *ip) { - char buf[512]; + char buf[BSIZE]; uint bn; struct dinode *dip; - bn = i2b(inum); + bn = IBLOCK(inum); + printf("winode %d\n", bn); rsect(bn, buf); dip = ((struct dinode*)buf) + (inum % IPB); *dip = *ip; @@ -193,11 +193,11 @@ winode(uint inum, struct dinode *ip) void rinode(uint inum, struct dinode *ip) { - char buf[512]; + char buf[BSIZE]; uint bn; struct dinode *dip; - bn = i2b(inum); + bn = IBLOCK(inum); rsect(bn, buf); dip = ((struct dinode*)buf) + (inum % IPB); *ip = *dip; @@ -206,11 +206,11 @@ rinode(uint inum, struct dinode *ip) void rsect(uint sec, void *buf) { - if(lseek(fsfd, sec * 512L, 0) != sec * 512L){ + if(lseek(fsfd, sec * BSIZE, 0) != sec * BSIZE){ perror("lseek"); exit(1); } - if(read(fsfd, buf, 512) != 512){ + if(read(fsfd, buf, BSIZE) != BSIZE){ perror("read"); exit(1); } @@ -233,17 +233,17 @@ ialloc(ushort type) void balloc(int used) { - uchar buf[512]; + uchar buf[BSIZE]; int i; printf("balloc: first %d blocks have been allocated\n", used); - assert(used < 512*8); - bzero(buf, 512); + assert(used < BSIZE*8); + bzero(buf, BSIZE); for(i = 0; i < used; i++){ buf[i/8] = buf[i/8] | (0x1 << (i%8)); } - printf("balloc: write bitmap block at sector %zu\n", ninodes/IPB + 3); - wsect(ninodes / IPB + 3, buf); + printf("balloc: write bitmap block at sector %d\n", ninodeblocks+2); + wsect(ninodeblocks+2, buf); } #define min(a, b) ((a) < (b) ? (a) : (b)) @@ -254,7 +254,7 @@ iappend(uint inum, void *xp, int n) char *p = (char*)xp; uint fbn, off, n1; struct dinode din; - char buf[512]; + char buf[BSIZE]; uint indirect[NINDIRECT]; uint x; @@ -262,32 +262,29 @@ iappend(uint inum, void *xp, int n) off = xint(din.size); while(n > 0){ - fbn = off / 512; + fbn = off / BSIZE; assert(fbn < MAXFILE); if(fbn < NDIRECT){ if(xint(din.addrs[fbn]) == 0){ din.addrs[fbn] = xint(freeblock++); - usedblocks++; } x = xint(din.addrs[fbn]); } else { if(xint(din.addrs[NDIRECT]) == 0){ // printf("allocate indirect block\n"); din.addrs[NDIRECT] = xint(freeblock++); - usedblocks++; } // printf("read indirect block\n"); rsect(xint(din.addrs[NDIRECT]), (char*)indirect); if(indirect[fbn - NDIRECT] == 0){ indirect[fbn - NDIRECT] = xint(freeblock++); - usedblocks++; wsect(xint(din.addrs[NDIRECT]), (char*)indirect); } x = xint(indirect[fbn-NDIRECT]); } - n1 = min(n, (fbn + 1) * 512 - off); + n1 = min(n, (fbn + 1) * BSIZE - off); rsect(x, buf); - bcopy(p, buf + off - (fbn * 512), n1); + bcopy(p, buf + off - (fbn * BSIZE), n1); wsect(x, buf); n -= n1; off += n1; diff --git a/param.h b/param.h index 8e007ca3f6..1a73f42adb 100644 --- a/param.h +++ b/param.h @@ -8,6 +8,6 @@ #define ROOTDEV 1 // device number of file system root disk #define MAXARG 32 // max exec arguments #define MAXOPBLOCKS 10 // max # of blocks any FS op writes -#define LOGSIZE (MAXOPBLOCKS*3) // max data sectors in on-disk log +#define LOGSIZE (MAXOPBLOCKS*3) // max data blocks in on-disk log #define NBUF (MAXOPBLOCKS*3) // size of disk block cache