Initial Spring 2016 commit.
This commit is contained in:
Geoffrey Challen
464
userland/sbin/sfsck/sfs.c
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464
userland/sbin/sfsck/sfs.c
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/*
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* Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2009, 2013
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* The President and Fellows of Harvard College.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <assert.h>
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#include <err.h>
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#include "compat.h"
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#include <kern/sfs.h>
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#include "disk.h"
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#include "utils.h"
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#include "ibmacros.h"
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#include "sfs.h"
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#include "main.h"
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////////////////////////////////////////////////////////////
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// global setup
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void
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sfs_setup(void)
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{
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assert(sizeof(struct sfs_superblock)==SFS_BLOCKSIZE);
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assert(sizeof(struct sfs_dinode)==SFS_BLOCKSIZE);
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assert(SFS_BLOCKSIZE % sizeof(struct sfs_direntry) == 0);
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}
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////////////////////////////////////////////////////////////
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// byte-swap functions
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static
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void
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swapsb(struct sfs_superblock *sb)
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{
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sb->sb_magic = SWAP32(sb->sb_magic);
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sb->sb_nblocks = SWAP32(sb->sb_nblocks);
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}
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static
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void
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swapbits(uint8_t *bits)
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{
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/* nothing to do */
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(void)bits;
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}
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static
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void
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swapinode(struct sfs_dinode *sfi)
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{
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int i;
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sfi->sfi_size = SWAP32(sfi->sfi_size);
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sfi->sfi_type = SWAP16(sfi->sfi_type);
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sfi->sfi_linkcount = SWAP16(sfi->sfi_linkcount);
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for (i=0; i<NUM_D; i++) {
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SET_D(sfi, i) = SWAP32(GET_D(sfi, i));
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}
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for (i=0; i<NUM_I; i++) {
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SET_I(sfi, i) = SWAP32(GET_I(sfi, i));
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}
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for (i=0; i<NUM_II; i++) {
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SET_II(sfi, i) = SWAP32(GET_II(sfi, i));
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}
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for (i=0; i<NUM_III; i++) {
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SET_III(sfi, i) = SWAP32(GET_III(sfi, i));
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}
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}
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static
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void
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swapdir(struct sfs_direntry *sfd)
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{
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sfd->sfd_ino = SWAP32(sfd->sfd_ino);
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}
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static
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void
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swapindir(uint32_t *entries)
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{
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int i;
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for (i=0; i<SFS_DBPERIDB; i++) {
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entries[i] = SWAP32(entries[i]);
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}
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}
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////////////////////////////////////////////////////////////
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// bmap()
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/*
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* Indirect block bmap: in indirect block IBLOCK, read the entry at
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* block OFFSET from the first file block mapped by this indirect
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* block.
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*
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* ENTRYSIZE is how many blocks each entry describes; for a
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* singly-indirect block this is 1. For a multiply-indirect block,
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* it is more than 1; in this case recurse.
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*/
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static
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uint32_t
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ibmap(uint32_t iblock, uint32_t offset, uint32_t entrysize)
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{
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uint32_t entries[SFS_DBPERIDB];
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if (iblock == 0) {
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return 0;
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}
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diskread(entries, iblock);
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swapindir(entries);
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if (entrysize > 1) {
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uint32_t index = offset / entrysize;
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offset %= entrysize;
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return ibmap(entries[index], offset, entrysize/SFS_DBPERIDB);
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}
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else {
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assert(offset < SFS_DBPERIDB);
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return entries[offset];
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}
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}
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/*
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* bmap() for SFS.
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*
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* Given an inode and a file block, returns a disk block.
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*/
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static
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uint32_t
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bmap(const struct sfs_dinode *sfi, uint32_t fileblock)
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{
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uint32_t iblock, offset;
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if (fileblock < INOMAX_D) {
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return GET_D(sfi, fileblock);
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}
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else if (fileblock < INOMAX_I) {
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iblock = (fileblock - INOMAX_D) / RANGE_I;
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offset = (fileblock - INOMAX_D) % RANGE_I;
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return ibmap(GET_I(sfi, iblock), offset, RANGE_D);
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}
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else if (fileblock < INOMAX_II) {
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iblock = (fileblock - INOMAX_I) / RANGE_II;
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offset = (fileblock - INOMAX_I) % RANGE_II;
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return ibmap(GET_II(sfi, iblock), offset, RANGE_I);
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}
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else if (fileblock < INOMAX_III) {
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iblock = (fileblock - INOMAX_II) / RANGE_III;
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offset = (fileblock - INOMAX_II) % RANGE_III;
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return ibmap(GET_III(sfi, iblock), offset, RANGE_II);
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}
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return 0;
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}
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////////////////////////////////////////////////////////////
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// superblock, free block bitmap, and inode I/O
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/*
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* superblock - blocknum is a disk block number.
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*/
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void
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sfs_readsb(uint32_t blocknum, struct sfs_superblock *sb)
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{
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diskread(sb, blocknum);
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swapsb(sb);
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}
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void
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sfs_writesb(uint32_t blocknum, struct sfs_superblock *sb)
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{
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swapsb(sb);
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diskwrite(sb, blocknum);
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swapsb(sb);
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}
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/*
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* freemap blocks - whichblock is a block number within the free block
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* bitmap.
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*/
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void
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sfs_readfreemapblock(uint32_t whichblock, uint8_t *bits)
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{
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diskread(bits, SFS_FREEMAP_START + whichblock);
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swapbits(bits);
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}
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void
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sfs_writefreemapblock(uint32_t whichblock, uint8_t *bits)
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{
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swapbits(bits);
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diskwrite(bits, SFS_FREEMAP_START + whichblock);
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swapbits(bits);
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}
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/*
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* inodes - ino is an inode number, which is a disk block number.
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*/
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void
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sfs_readinode(uint32_t ino, struct sfs_dinode *sfi)
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{
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diskread(sfi, ino);
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swapinode(sfi);
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}
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void
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sfs_writeinode(uint32_t ino, struct sfs_dinode *sfi)
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{
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swapinode(sfi);
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diskwrite(sfi, ino);
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swapinode(sfi);
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}
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/*
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* indirect blocks - blocknum is a disk block number.
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*/
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void
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sfs_readindirect(uint32_t blocknum, uint32_t *entries)
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{
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diskread(entries, blocknum);
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swapindir(entries);
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}
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void
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sfs_writeindirect(uint32_t blocknum, uint32_t *entries)
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{
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swapindir(entries);
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diskwrite(entries, blocknum);
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swapindir(entries);
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}
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////////////////////////////////////////////////////////////
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// directory I/O
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/*
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* Read the directory block at DISKBLOCK into D.
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*/
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static
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void
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sfs_readdirblock(struct sfs_direntry *d, uint32_t diskblock)
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{
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const unsigned atonce = SFS_BLOCKSIZE/sizeof(struct sfs_direntry);
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unsigned j;
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if (diskblock != 0) {
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diskread(d, diskblock);
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for (j=0; j<atonce; j++) {
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swapdir(&d[j]);
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}
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}
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else {
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warnx("Warning: sparse directory found");
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bzero(d, SFS_BLOCKSIZE);
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}
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}
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/*
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* Read in a directory, from the inode SFI, into D, which is a buffer
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* with ND slots. The caller is assumed to have figured out the right
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* number of slots.
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*/
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void
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sfs_readdir(struct sfs_dinode *sfi, struct sfs_direntry *d, unsigned nd)
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{
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const unsigned atonce = SFS_BLOCKSIZE/sizeof(struct sfs_direntry);
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unsigned nblocks = SFS_ROUNDUP(nd, atonce) / atonce;
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unsigned i, j;
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unsigned left, thismany;
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struct sfs_direntry buffer[atonce];
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uint32_t diskblock;
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left = nd;
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for (i=0; i<nblocks; i++) {
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diskblock = bmap(sfi, i);
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if (left < atonce) {
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thismany = left;
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sfs_readdirblock(buffer, diskblock);
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for (j=0; j<thismany; j++) {
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d[i*atonce + j] = buffer[j];
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}
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}
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else {
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thismany = atonce;
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sfs_readdirblock(d + i*atonce, diskblock);
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}
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left -= thismany;
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}
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assert(left == 0);
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}
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/*
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* Write the directory block D to DISKBLOCK.
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*/
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static
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void
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sfs_writedirblock(struct sfs_direntry *d, uint32_t diskblock)
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{
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const unsigned atonce = SFS_BLOCKSIZE/sizeof(struct sfs_direntry);
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unsigned j, bad;
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if (diskblock != 0) {
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for (j=0; j<atonce; j++) {
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swapdir(&d[j]);
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}
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diskwrite(d, diskblock);
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}
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else {
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for (j=bad=0; j<atonce; j++) {
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if (d[j].sfd_ino != SFS_NOINO ||
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d[j].sfd_name[0] != 0) {
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bad = 1;
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}
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}
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if (bad) {
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warnx("Cannot write to missing block in "
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"sparse directory (ERROR)");
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setbadness(EXIT_UNRECOV);
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}
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}
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}
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/*
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* Write out a directory, from the inode SFI, using D, which is a
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* buffer with ND slots. The caller is assumed to have set the inode
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* size accordingly.
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*/
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void
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sfs_writedir(const struct sfs_dinode *sfi, struct sfs_direntry *d, unsigned nd)
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{
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const unsigned atonce = SFS_BLOCKSIZE/sizeof(struct sfs_direntry);
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unsigned nblocks = SFS_ROUNDUP(nd, atonce) / atonce;
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unsigned i, j;
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unsigned left, thismany;
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struct sfs_direntry buffer[atonce];
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uint32_t diskblock;
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left = nd;
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for (i=0; i<nblocks; i++) {
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diskblock = bmap(sfi, i);
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if (left < atonce) {
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thismany = left;
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for (j=0; j<thismany; j++) {
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buffer[j] = d[i*atonce + j];
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}
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for (; j<atonce; j++) {
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memset(&buffer[j], 0, sizeof(buffer[j]));
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}
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sfs_writedirblock(buffer, diskblock);
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}
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else {
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thismany = atonce;
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sfs_writedirblock(d + i*atonce, diskblock);
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}
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left -= thismany;
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}
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assert(left == 0);
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}
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////////////////////////////////////////////////////////////
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// directory utilities
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/* this exists because qsort() doesn't pass a context pointer through */
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static struct sfs_direntry *global_sortdirs;
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/*
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* Compare function for the permutation vector produced by
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* sfsdir_sort().
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*/
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static
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int
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dirsortfunc(const void *aa, const void *bb)
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{
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const int *a = (const int *)aa;
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const int *b = (const int *)bb;
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const struct sfs_direntry *ad = &global_sortdirs[*a];
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const struct sfs_direntry *bd = &global_sortdirs[*b];
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/* Sort unallocated entries last */
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if (ad->sfd_ino == SFS_NOINO && bd->sfd_ino == SFS_NOINO) {
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return 0;
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}
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if (ad->sfd_ino == SFS_NOINO) {
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return 1;
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}
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if (bd->sfd_ino == SFS_NOINO) {
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return -1;
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}
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return strcmp(ad->sfd_name, bd->sfd_name);
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}
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/*
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* Sort the directory contents in D (with ND entries) by producing a
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* permutation vector into VECTOR, which should be allocated to hold
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* ND ints.
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*/
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void
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sfsdir_sort(struct sfs_direntry *d, unsigned nd, int *vector)
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{
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unsigned i;
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for (i=0; i<nd; i++) {
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vector[i] = i;
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}
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global_sortdirs = d;
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qsort(vector, nd, sizeof(int), dirsortfunc);
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}
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/*
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* Try to add an entry NAME/INO to D (which has ND entries) by
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* finding an empty slot. Cannot allocate new space.
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*
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* Returns 0 on success and nonzero on failure.
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*/
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int
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sfsdir_tryadd(struct sfs_direntry *d, int nd, const char *name, uint32_t ino)
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{
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int i;
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for (i=0; i<nd; i++) {
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if (d[i].sfd_ino==SFS_NOINO) {
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d[i].sfd_ino = ino;
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assert(strlen(name) < sizeof(d[i].sfd_name));
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strcpy(d[i].sfd_name, name);
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return 0;
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}
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}
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return -1;
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}
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