2015-12-23 00:50:04 +00:00

267 lines
6.5 KiB
C

/*
* Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2009, 2013
* The President and Fellows of Harvard College.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <err.h>
#include "compat.h"
#include <kern/sfs.h>
#include "utils.h"
#include "sfs.h"
#include "freemap.h"
#include "inode.h"
#include "main.h"
/*
* Stuff we remember about inodes.
* FUTURE: should count the number of blocks allocated to this inode
*/
struct inodeinfo {
uint32_t ino;
uint32_t linkcount; /* files only */
int visited; /* dirs only */
int type;
};
/* Table of inodes found. */
static struct inodeinfo *inodes = NULL;
static unsigned ninodes = 0, maxinodes = 0;
/* Whether the table is sorted and can be looked up with binary search. */
static int inodes_sorted = 0;
////////////////////////////////////////////////////////////
// inode table ops
/*
* Add an entry to the inode table, realloc'ing it if needed.
*/
static
void
inode_addtable(uint32_t ino, int type)
{
unsigned newmax;
assert(ninodes <= maxinodes);
if (ninodes == maxinodes) {
newmax = maxinodes ? maxinodes * 2 : 4;
inodes = dorealloc(inodes, maxinodes * sizeof(inodes[0]),
newmax * sizeof(inodes[0]));
maxinodes = newmax;
}
inodes[ninodes].ino = ino;
inodes[ninodes].linkcount = 0;
inodes[ninodes].visited = 0;
inodes[ninodes].type = type;
ninodes++;
inodes_sorted = 0;
}
/*
* Compare function for inodes.
*/
static
int
inode_compare(const void *av, const void *bv)
{
const struct inodeinfo *a = av;
const struct inodeinfo *b = bv;
if (a->ino < b->ino) {
return -1;
}
if (a->ino > b->ino) {
return 1;
}
/*
* There should be no duplicates in the table! But C99 makes
* no guarantees about whether the implementation of qsort can
* ask us to compare an element to itself. Assert that this is
* what happened.
*/
assert(av == bv);
return 0;
}
/*
* After pass1, we sort the inode table for faster access.
*/
void
inode_sorttable(void)
{
qsort(inodes, ninodes, sizeof(inodes[0]), inode_compare);
inodes_sorted = 1;
}
/*
* Find an inode by binary search.
*
* This will error out if asked for an inode not in the table; that's
* not supposed to happen. (This might need to change; if we improve
* the handling of crosslinked directories as suggested in comments in
* pass2.c, we'll need to be able to ask if an inode number is valid
* and names a directory.)
*/
static
struct inodeinfo *
inode_find(uint32_t ino)
{
unsigned min, max, i;
assert(inodes_sorted);
assert(ninodes > 0);
min = 0;
max = ninodes;
while (1) {
assert(min <= max);
if (min == max) {
errx(EXIT_UNRECOV, "FATAL: inode %u wasn't found in my inode table", ino);
}
i = min + (max - min)/2;
if (inodes[i].ino < ino) {
min = i + 1;
}
else if (inodes[i].ino > ino) {
max = i;
}
else {
assert(inodes[i].ino == ino);
return &inodes[i];
}
}
/* NOTREACHED */
}
////////////////////////////////////////////////////////////
// inode ops
/*
* Add an inode; returns 1 if we've already seen it.
*
* Uses linear search because we only sort the table for faster access
* after all inodes have been added. In the FUTURE this could be
* changed to a better data structure.
*/
int
inode_add(uint32_t ino, int type)
{
unsigned i;
for (i=0; i<ninodes; i++) {
if (inodes[i].ino==ino) {
assert(inodes[i].linkcount == 0);
assert(inodes[i].type == type);
return 1;
}
}
inode_addtable(ino, type);
return 0;
}
/*
* Mark an inode (directories only, because that's all the caller
* does) visited. Returns nonzero if already visited.
*
* Note that there is no way to clear the visited flag for now because
* it's only used once (by pass2).
*/
int
inode_visitdir(uint32_t ino)
{
struct inodeinfo *inf;
inf = inode_find(ino);
assert(inf->type == SFS_TYPE_DIR);
assert(inf->linkcount == 0);
if (inf->visited) {
return 1;
}
inf->visited = 1;
return 0;
}
/*
* Count a link. Only for regular files because that's what the caller
* does. (And that, in turn, is because the link count of a directory
* is a local property.)
*/
void
inode_addlink(uint32_t ino)
{
struct inodeinfo *inf;
inf = inode_find(ino);
assert(inf->type == SFS_TYPE_FILE);
assert(inf->visited == 0);
inf->linkcount++;
}
/*
* Correct link counts. This is effectively pass3. (FUTURE: change the
* name accordingly.)
*/
void
inode_adjust_filelinks(void)
{
struct sfs_dinode sfi;
unsigned i;
for (i=0; i<ninodes; i++) {
if (inodes[i].type == SFS_TYPE_DIR) {
/* directory */
continue;
}
assert(inodes[i].type == SFS_TYPE_FILE);
/* because we've seen it, there must be at least one link */
assert(inodes[i].linkcount > 0);
sfs_readinode(inodes[i].ino, &sfi);
assert(sfi.sfi_type == SFS_TYPE_FILE);
if (sfi.sfi_linkcount != inodes[i].linkcount) {
warnx("File %lu link count %lu should be %lu (fixed)",
(unsigned long) inodes[i].ino,
(unsigned long) sfi.sfi_linkcount,
(unsigned long) inodes[i].linkcount);
sfi.sfi_linkcount = inodes[i].linkcount;
setbadness(EXIT_RECOV);
sfs_writeinode(inodes[i].ino, &sfi);
}
}
}