mirror of
https://github.com/sheumann/hush.git
synced 2024-08-16 09:29:16 +00:00
468 lines
11 KiB
C
468 lines
11 KiB
C
/* vi: set sw=4 ts=4: */
|
|
/*
|
|
* icount.c --- an efficient inode count abstraction
|
|
*
|
|
* Copyright (C) 1997 Theodore Ts'o.
|
|
*
|
|
* %Begin-Header%
|
|
* This file may be redistributed under the terms of the GNU Public
|
|
* License.
|
|
* %End-Header%
|
|
*/
|
|
|
|
#if HAVE_UNISTD_H
|
|
#include <unistd.h>
|
|
#endif
|
|
#include <string.h>
|
|
#include <stdio.h>
|
|
|
|
#include "ext2_fs.h"
|
|
#include "ext2fs.h"
|
|
|
|
/*
|
|
* The data storage strategy used by icount relies on the observation
|
|
* that most inode counts are either zero (for non-allocated inodes),
|
|
* one (for most files), and only a few that are two or more
|
|
* (directories and files that are linked to more than one directory).
|
|
*
|
|
* Also, e2fsck tends to load the icount data sequentially.
|
|
*
|
|
* So, we use an inode bitmap to indicate which inodes have a count of
|
|
* one, and then use a sorted list to store the counts for inodes
|
|
* which are greater than one.
|
|
*
|
|
* We also use an optional bitmap to indicate which inodes are already
|
|
* in the sorted list, to speed up the use of this abstraction by
|
|
* e2fsck's pass 2. Pass 2 increments inode counts as it finds them,
|
|
* so this extra bitmap avoids searching the sorted list to see if a
|
|
* particular inode is on the sorted list already.
|
|
*/
|
|
|
|
struct ext2_icount_el {
|
|
ext2_ino_t ino;
|
|
__u16 count;
|
|
};
|
|
|
|
struct ext2_icount {
|
|
errcode_t magic;
|
|
ext2fs_inode_bitmap single;
|
|
ext2fs_inode_bitmap multiple;
|
|
ext2_ino_t count;
|
|
ext2_ino_t size;
|
|
ext2_ino_t num_inodes;
|
|
ext2_ino_t cursor;
|
|
struct ext2_icount_el *list;
|
|
};
|
|
|
|
void ext2fs_free_icount(ext2_icount_t icount)
|
|
{
|
|
if (!icount)
|
|
return;
|
|
|
|
icount->magic = 0;
|
|
ext2fs_free_mem(&icount->list);
|
|
ext2fs_free_inode_bitmap(icount->single);
|
|
ext2fs_free_inode_bitmap(icount->multiple);
|
|
ext2fs_free_mem(&icount);
|
|
}
|
|
|
|
errcode_t ext2fs_create_icount2(ext2_filsys fs, int flags, unsigned int size,
|
|
ext2_icount_t hint, ext2_icount_t *ret)
|
|
{
|
|
ext2_icount_t icount;
|
|
errcode_t retval;
|
|
size_t bytes;
|
|
ext2_ino_t i;
|
|
|
|
if (hint) {
|
|
EXT2_CHECK_MAGIC(hint, EXT2_ET_MAGIC_ICOUNT);
|
|
if (hint->size > size)
|
|
size = (size_t) hint->size;
|
|
}
|
|
|
|
retval = ext2fs_get_mem(sizeof(struct ext2_icount), &icount);
|
|
if (retval)
|
|
return retval;
|
|
memset(icount, 0, sizeof(struct ext2_icount));
|
|
|
|
retval = ext2fs_allocate_inode_bitmap(fs, 0,
|
|
&icount->single);
|
|
if (retval)
|
|
goto errout;
|
|
|
|
if (flags & EXT2_ICOUNT_OPT_INCREMENT) {
|
|
retval = ext2fs_allocate_inode_bitmap(fs, 0,
|
|
&icount->multiple);
|
|
if (retval)
|
|
goto errout;
|
|
} else
|
|
icount->multiple = 0;
|
|
|
|
if (size) {
|
|
icount->size = size;
|
|
} else {
|
|
/*
|
|
* Figure out how many special case inode counts we will
|
|
* have. We know we will need one for each directory;
|
|
* we also need to reserve some extra room for file links
|
|
*/
|
|
retval = ext2fs_get_num_dirs(fs, &icount->size);
|
|
if (retval)
|
|
goto errout;
|
|
icount->size += fs->super->s_inodes_count / 50;
|
|
}
|
|
|
|
bytes = (size_t) (icount->size * sizeof(struct ext2_icount_el));
|
|
retval = ext2fs_get_mem(bytes, &icount->list);
|
|
if (retval)
|
|
goto errout;
|
|
memset(icount->list, 0, bytes);
|
|
|
|
icount->magic = EXT2_ET_MAGIC_ICOUNT;
|
|
icount->count = 0;
|
|
icount->cursor = 0;
|
|
icount->num_inodes = fs->super->s_inodes_count;
|
|
|
|
/*
|
|
* Populate the sorted list with those entries which were
|
|
* found in the hint icount (since those are ones which will
|
|
* likely need to be in the sorted list this time around).
|
|
*/
|
|
if (hint) {
|
|
for (i=0; i < hint->count; i++)
|
|
icount->list[i].ino = hint->list[i].ino;
|
|
icount->count = hint->count;
|
|
}
|
|
|
|
*ret = icount;
|
|
return 0;
|
|
|
|
errout:
|
|
ext2fs_free_icount(icount);
|
|
return retval;
|
|
}
|
|
|
|
errcode_t ext2fs_create_icount(ext2_filsys fs, int flags,
|
|
unsigned int size,
|
|
ext2_icount_t *ret)
|
|
{
|
|
return ext2fs_create_icount2(fs, flags, size, 0, ret);
|
|
}
|
|
|
|
/*
|
|
* insert_icount_el() --- Insert a new entry into the sorted list at a
|
|
* specified position.
|
|
*/
|
|
static struct ext2_icount_el *insert_icount_el(ext2_icount_t icount,
|
|
ext2_ino_t ino, int pos)
|
|
{
|
|
struct ext2_icount_el *el;
|
|
errcode_t retval;
|
|
ext2_ino_t new_size = 0;
|
|
int num;
|
|
|
|
if (icount->count >= icount->size) {
|
|
if (icount->count) {
|
|
new_size = icount->list[(unsigned)icount->count-1].ino;
|
|
new_size = (ext2_ino_t) (icount->count *
|
|
((float) icount->num_inodes / new_size));
|
|
}
|
|
if (new_size < (icount->size + 100))
|
|
new_size = icount->size + 100;
|
|
retval = ext2fs_resize_mem((size_t) icount->size *
|
|
sizeof(struct ext2_icount_el),
|
|
(size_t) new_size *
|
|
sizeof(struct ext2_icount_el),
|
|
&icount->list);
|
|
if (retval)
|
|
return 0;
|
|
icount->size = new_size;
|
|
}
|
|
num = (int) icount->count - pos;
|
|
if (num < 0)
|
|
return 0; /* should never happen */
|
|
if (num) {
|
|
memmove(&icount->list[pos+1], &icount->list[pos],
|
|
sizeof(struct ext2_icount_el) * num);
|
|
}
|
|
icount->count++;
|
|
el = &icount->list[pos];
|
|
el->count = 0;
|
|
el->ino = ino;
|
|
return el;
|
|
}
|
|
|
|
/*
|
|
* get_icount_el() --- given an inode number, try to find icount
|
|
* information in the sorted list. If the create flag is set,
|
|
* and we can't find an entry, create one in the sorted list.
|
|
*/
|
|
static struct ext2_icount_el *get_icount_el(ext2_icount_t icount,
|
|
ext2_ino_t ino, int create)
|
|
{
|
|
float range;
|
|
int low, high, mid;
|
|
ext2_ino_t lowval, highval;
|
|
|
|
if (!icount || !icount->list)
|
|
return 0;
|
|
|
|
if (create && ((icount->count == 0) ||
|
|
(ino > icount->list[(unsigned)icount->count-1].ino))) {
|
|
return insert_icount_el(icount, ino, (unsigned) icount->count);
|
|
}
|
|
if (icount->count == 0)
|
|
return 0;
|
|
|
|
if (icount->cursor >= icount->count)
|
|
icount->cursor = 0;
|
|
if (ino == icount->list[icount->cursor].ino)
|
|
return &icount->list[icount->cursor++];
|
|
low = 0;
|
|
high = (int) icount->count-1;
|
|
while (low <= high) {
|
|
if (low == high)
|
|
mid = low;
|
|
else {
|
|
/* Interpolate for efficiency */
|
|
lowval = icount->list[low].ino;
|
|
highval = icount->list[high].ino;
|
|
|
|
if (ino < lowval)
|
|
range = 0;
|
|
else if (ino > highval)
|
|
range = 1;
|
|
else
|
|
range = ((float) (ino - lowval)) /
|
|
(highval - lowval);
|
|
mid = low + ((int) (range * (high-low)));
|
|
}
|
|
if (ino == icount->list[mid].ino) {
|
|
icount->cursor = mid+1;
|
|
return &icount->list[mid];
|
|
}
|
|
if (ino < icount->list[mid].ino)
|
|
high = mid-1;
|
|
else
|
|
low = mid+1;
|
|
}
|
|
/*
|
|
* If we need to create a new entry, it should be right at
|
|
* low (where high will be left at low-1).
|
|
*/
|
|
if (create)
|
|
return insert_icount_el(icount, ino, low);
|
|
return 0;
|
|
}
|
|
|
|
errcode_t ext2fs_icount_validate(ext2_icount_t icount, FILE *out)
|
|
{
|
|
errcode_t ret = 0;
|
|
unsigned int i;
|
|
const char *bad = "bad icount";
|
|
|
|
EXT2_CHECK_MAGIC(icount, EXT2_ET_MAGIC_ICOUNT);
|
|
|
|
if (icount->count > icount->size) {
|
|
fprintf(out, "%s: count > size\n", bad);
|
|
return EXT2_ET_INVALID_ARGUMENT;
|
|
}
|
|
for (i=1; i < icount->count; i++) {
|
|
if (icount->list[i-1].ino >= icount->list[i].ino) {
|
|
fprintf(out, "%s: list[%d].ino=%u, list[%d].ino=%u\n",
|
|
bad, i-1, icount->list[i-1].ino,
|
|
i, icount->list[i].ino);
|
|
ret = EXT2_ET_INVALID_ARGUMENT;
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
errcode_t ext2fs_icount_fetch(ext2_icount_t icount, ext2_ino_t ino, __u16 *ret)
|
|
{
|
|
struct ext2_icount_el *el;
|
|
|
|
EXT2_CHECK_MAGIC(icount, EXT2_ET_MAGIC_ICOUNT);
|
|
|
|
if (!ino || (ino > icount->num_inodes))
|
|
return EXT2_ET_INVALID_ARGUMENT;
|
|
|
|
if (ext2fs_test_inode_bitmap(icount->single, ino)) {
|
|
*ret = 1;
|
|
return 0;
|
|
}
|
|
if (icount->multiple &&
|
|
!ext2fs_test_inode_bitmap(icount->multiple, ino)) {
|
|
*ret = 0;
|
|
return 0;
|
|
}
|
|
el = get_icount_el(icount, ino, 0);
|
|
if (!el) {
|
|
*ret = 0;
|
|
return 0;
|
|
}
|
|
*ret = el->count;
|
|
return 0;
|
|
}
|
|
|
|
errcode_t ext2fs_icount_increment(ext2_icount_t icount, ext2_ino_t ino,
|
|
__u16 *ret)
|
|
{
|
|
struct ext2_icount_el *el;
|
|
|
|
EXT2_CHECK_MAGIC(icount, EXT2_ET_MAGIC_ICOUNT);
|
|
|
|
if (!ino || (ino > icount->num_inodes))
|
|
return EXT2_ET_INVALID_ARGUMENT;
|
|
|
|
if (ext2fs_test_inode_bitmap(icount->single, ino)) {
|
|
/*
|
|
* If the existing count is 1, then we know there is
|
|
* no entry in the list.
|
|
*/
|
|
el = get_icount_el(icount, ino, 1);
|
|
if (!el)
|
|
return EXT2_ET_NO_MEMORY;
|
|
ext2fs_unmark_inode_bitmap(icount->single, ino);
|
|
el->count = 2;
|
|
} else if (icount->multiple) {
|
|
/*
|
|
* The count is either zero or greater than 1; if the
|
|
* inode is set in icount->multiple, then there should
|
|
* be an entry in the list, so find it using
|
|
* get_icount_el().
|
|
*/
|
|
if (ext2fs_test_inode_bitmap(icount->multiple, ino)) {
|
|
el = get_icount_el(icount, ino, 1);
|
|
if (!el)
|
|
return EXT2_ET_NO_MEMORY;
|
|
el->count++;
|
|
} else {
|
|
/*
|
|
* The count was zero; mark the single bitmap
|
|
* and return.
|
|
*/
|
|
zero_count:
|
|
ext2fs_mark_inode_bitmap(icount->single, ino);
|
|
if (ret)
|
|
*ret = 1;
|
|
return 0;
|
|
}
|
|
} else {
|
|
/*
|
|
* The count is either zero or greater than 1; try to
|
|
* find an entry in the list to determine which.
|
|
*/
|
|
el = get_icount_el(icount, ino, 0);
|
|
if (!el) {
|
|
/* No entry means the count was zero */
|
|
goto zero_count;
|
|
}
|
|
el = get_icount_el(icount, ino, 1);
|
|
if (!el)
|
|
return EXT2_ET_NO_MEMORY;
|
|
el->count++;
|
|
}
|
|
if (icount->multiple)
|
|
ext2fs_mark_inode_bitmap(icount->multiple, ino);
|
|
if (ret)
|
|
*ret = el->count;
|
|
return 0;
|
|
}
|
|
|
|
errcode_t ext2fs_icount_decrement(ext2_icount_t icount, ext2_ino_t ino,
|
|
__u16 *ret)
|
|
{
|
|
struct ext2_icount_el *el;
|
|
|
|
if (!ino || (ino > icount->num_inodes))
|
|
return EXT2_ET_INVALID_ARGUMENT;
|
|
|
|
EXT2_CHECK_MAGIC(icount, EXT2_ET_MAGIC_ICOUNT);
|
|
|
|
if (ext2fs_test_inode_bitmap(icount->single, ino)) {
|
|
ext2fs_unmark_inode_bitmap(icount->single, ino);
|
|
if (icount->multiple)
|
|
ext2fs_unmark_inode_bitmap(icount->multiple, ino);
|
|
else {
|
|
el = get_icount_el(icount, ino, 0);
|
|
if (el)
|
|
el->count = 0;
|
|
}
|
|
if (ret)
|
|
*ret = 0;
|
|
return 0;
|
|
}
|
|
|
|
if (icount->multiple &&
|
|
!ext2fs_test_inode_bitmap(icount->multiple, ino))
|
|
return EXT2_ET_INVALID_ARGUMENT;
|
|
|
|
el = get_icount_el(icount, ino, 0);
|
|
if (!el || el->count == 0)
|
|
return EXT2_ET_INVALID_ARGUMENT;
|
|
|
|
el->count--;
|
|
if (el->count == 1)
|
|
ext2fs_mark_inode_bitmap(icount->single, ino);
|
|
if ((el->count == 0) && icount->multiple)
|
|
ext2fs_unmark_inode_bitmap(icount->multiple, ino);
|
|
|
|
if (ret)
|
|
*ret = el->count;
|
|
return 0;
|
|
}
|
|
|
|
errcode_t ext2fs_icount_store(ext2_icount_t icount, ext2_ino_t ino,
|
|
__u16 count)
|
|
{
|
|
struct ext2_icount_el *el;
|
|
|
|
if (!ino || (ino > icount->num_inodes))
|
|
return EXT2_ET_INVALID_ARGUMENT;
|
|
|
|
EXT2_CHECK_MAGIC(icount, EXT2_ET_MAGIC_ICOUNT);
|
|
|
|
if (count == 1) {
|
|
ext2fs_mark_inode_bitmap(icount->single, ino);
|
|
if (icount->multiple)
|
|
ext2fs_unmark_inode_bitmap(icount->multiple, ino);
|
|
return 0;
|
|
}
|
|
if (count == 0) {
|
|
ext2fs_unmark_inode_bitmap(icount->single, ino);
|
|
if (icount->multiple) {
|
|
/*
|
|
* If the icount->multiple bitmap is enabled,
|
|
* we can just clear both bitmaps and we're done
|
|
*/
|
|
ext2fs_unmark_inode_bitmap(icount->multiple, ino);
|
|
} else {
|
|
el = get_icount_el(icount, ino, 0);
|
|
if (el)
|
|
el->count = 0;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Get the icount element
|
|
*/
|
|
el = get_icount_el(icount, ino, 1);
|
|
if (!el)
|
|
return EXT2_ET_NO_MEMORY;
|
|
el->count = count;
|
|
ext2fs_unmark_inode_bitmap(icount->single, ino);
|
|
if (icount->multiple)
|
|
ext2fs_mark_inode_bitmap(icount->multiple, ino);
|
|
return 0;
|
|
}
|
|
|
|
ext2_ino_t ext2fs_get_icount_size(ext2_icount_t icount)
|
|
{
|
|
if (!icount || icount->magic != EXT2_ET_MAGIC_ICOUNT)
|
|
return 0;
|
|
|
|
return icount->size;
|
|
}
|