ref: 87a7e379a51eb7aaf4943a57298f67a15646f929
dir: /lwext4/ext4_balloc.c/
/*
* Copyright (c) 2013 Grzegorz Kostka ([email protected])
*
*
* HelenOS:
* Copyright (c) 2012 Martin Sucha
* Copyright (c) 2012 Frantisek Princ
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - 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.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
/** @addtogroup lwext4
* @{
*/
/**
* @file ext4_balloc.c
* @brief Physical block allocator.
*/
#include <ext4_config.h>
#include <ext4_balloc.h>
#include <ext4_super.h>
#include <ext4_block_group.h>
#include <ext4_fs.h>
#include <ext4_bitmap.h>
#include <ext4_inode.h>
/**@brief Compute number of block group from block address.
* @param sb Superblock pointer.
* @param baddr Absolute address of block.
* @return Block group index
*/
static uint32_t ext4_balloc_get_bgid_of_block(struct ext4_sblock *s,
uint32_t baddr)
{
if (ext4_get32(s, first_data_block))
baddr--;
return baddr / ext4_get32(s, blocks_per_group);
}
uint32_t
ext4_balloc_get_first_data_block_in_group(struct ext4_sblock *s,
struct ext4_block_group_ref *bg_ref)
{
uint32_t block_group_count = ext4_block_group_cnt(s);
uint32_t inode_table_first_block =
ext4_bg_get_inode_table_first_block(bg_ref->block_group, s);
uint32_t block_size = ext4_sb_get_block_size(s);
uint16_t inode_size = ext4_get16(s, inode_size);
uint32_t inodes_per_group = ext4_get32(s, inodes_per_group);
uint32_t inode_table_bytes;
if (bg_ref->index < block_group_count - 1) {
inode_table_bytes = inodes_per_group * inode_size;
} else {
/* Last block group could be smaller */
uint32_t inodes_count_total = ext4_get32(s, inodes_count);
inode_table_bytes = (inodes_count_total -
((block_group_count - 1) * inodes_per_group)) *
inode_size;
}
uint32_t inode_table_blocks = inode_table_bytes / block_size;
if (inode_table_bytes % block_size)
inode_table_blocks++;
return inode_table_first_block + inode_table_blocks;
}
int ext4_balloc_free_block(struct ext4_inode_ref *inode_ref, uint32_t baddr)
{
struct ext4_fs *fs = inode_ref->fs;
struct ext4_sblock *sb = &fs->sb;
uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, baddr);
uint32_t index_in_group = ext4_fs_baddr2_index_in_group(sb, baddr);
/* Load block group reference */
struct ext4_block_group_ref bg_ref;
int rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
if (rc != EOK)
return rc;
/* Load block with bitmap */
uint32_t bitmap_block_addr =
ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
struct ext4_block bitmap_block;
rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
if (rc != EOK) {
ext4_fs_put_block_group_ref(&bg_ref);
return rc;
}
/* Modify bitmap */
ext4_bmap_bit_clr(bitmap_block.data, index_in_group);
bitmap_block.dirty = true;
/* Release block with bitmap */
rc = ext4_block_set(fs->bdev, &bitmap_block);
if (rc != EOK) {
/* Error in saving bitmap */
ext4_fs_put_block_group_ref(&bg_ref);
return rc;
}
uint32_t block_size = ext4_sb_get_block_size(sb);
/* Update superblock free blocks count */
uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
sb_free_blocks++;
ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
/* Update inode blocks count */
uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
ino_blocks -= block_size / EXT4_INODE_BLOCK_SIZE;
ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
inode_ref->dirty = true;
/* Update block group free blocks count */
uint32_t free_blocks =
ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
free_blocks++;
ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, free_blocks);
bg_ref.dirty = true;
/* Release block group reference */
return ext4_fs_put_block_group_ref(&bg_ref);
}
int ext4_balloc_free_blocks(struct ext4_inode_ref *inode_ref, uint32_t first,
uint32_t count)
{
int rc = EOK;
struct ext4_fs *fs = inode_ref->fs;
struct ext4_sblock *sb = &fs->sb;
/* Compute indexes */
uint32_t block_group_first = ext4_balloc_get_bgid_of_block(sb, first);
/* Compute indexes */
uint32_t block_group_last =
ext4_balloc_get_bgid_of_block(sb, first + count - 1);
if (!ext4_sb_has_feature_incompatible(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
/*It is not possible withot flex_bg that blocks are continuous
* and and last block belongs to other bg.*/
ext4_assert(block_group_first ==
ext4_balloc_get_bgid_of_block(sb, first + count - 1));
}
/* Load block group reference */
struct ext4_block_group_ref bg_ref;
while (block_group_first <= block_group_last) {
rc = ext4_fs_get_block_group_ref(fs, block_group_first, &bg_ref);
if (rc != EOK)
return rc;
uint32_t index_in_group_first =
ext4_fs_baddr2_index_in_group(sb, first);
/* Load block with bitmap */
uint32_t bitmap_block_addr =
ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
struct ext4_block bitmap_block;
rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
if (rc != EOK) {
ext4_fs_put_block_group_ref(&bg_ref);
return rc;
}
uint32_t free_cnt =
ext4_sb_get_block_size(sb) * 8 - index_in_group_first;
/*If last block, free only count blocks*/
free_cnt = count > free_cnt ? free_cnt : count;
/* Modify bitmap */
ext4_bmap_bits_free(bitmap_block.data, index_in_group_first, free_cnt);
bitmap_block.dirty = true;
count -= free_cnt;
first += free_cnt;
/* Release block with bitmap */
rc = ext4_block_set(fs->bdev, &bitmap_block);
if (rc != EOK) {
ext4_fs_put_block_group_ref(&bg_ref);
return rc;
}
uint32_t block_size = ext4_sb_get_block_size(sb);
/* Update superblock free blocks count */
uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
sb_free_blocks += free_cnt;
ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
/* Update inode blocks count */
uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
ino_blocks -= free_cnt * (block_size / EXT4_INODE_BLOCK_SIZE);
ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
inode_ref->dirty = true;
/* Update block group free blocks count */
uint32_t free_blocks =
ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
free_blocks += free_cnt;
ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, free_blocks);
bg_ref.dirty = true;
/* Release block group reference */
rc = ext4_fs_put_block_group_ref(&bg_ref);
if (rc != EOK)
break;
block_group_first++;
}
/*All blocks should be released*/
ext4_assert(count == 0);
return rc;
}
/**@brief Compute 'goal' for allocation algorithm.
* @param inode_ref Reference to inode, to allocate block for
* @param goal
* @return error code
*/
static int ext4_balloc_find_goal(struct ext4_inode_ref *inode_ref,
uint32_t *goal)
{
struct ext4_sblock *sb = &inode_ref->fs->sb;
*goal = 0;
uint64_t inode_size = ext4_inode_get_size(sb, inode_ref->inode);
uint32_t block_size = ext4_sb_get_block_size(sb);
uint32_t inode_block_count = inode_size / block_size;
if (inode_size % block_size != 0)
inode_block_count++;
/* If inode has some blocks, get last block address + 1 */
if (inode_block_count > 0) {
int rc = ext4_fs_get_inode_data_block_index(
inode_ref, inode_block_count - 1, goal);
if (rc != EOK)
return rc;
if (*goal != 0) {
(*goal)++;
return rc;
}
/* If goal == 0, sparse file -> continue */
}
/* Identify block group of inode */
uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);
uint32_t block_group = (inode_ref->index - 1) / inodes_per_group;
block_size = ext4_sb_get_block_size(sb);
/* Load block group reference */
struct ext4_block_group_ref bg_ref;
int rc = ext4_fs_get_block_group_ref(inode_ref->fs, block_group, &bg_ref);
if (rc != EOK)
return rc;
/* Compute indexes */
uint32_t block_group_count = ext4_block_group_cnt(sb);
uint32_t inode_table_first_block =
ext4_bg_get_inode_table_first_block(bg_ref.block_group, sb);
uint16_t inode_table_item_size = ext4_get16(sb, inode_size);
uint32_t inode_table_bytes;
/* Check for last block group */
if (block_group < block_group_count - 1) {
inode_table_bytes = inodes_per_group * inode_table_item_size;
} else {
/* Last block group could be smaller */
uint32_t inodes_count_total = ext4_get32(sb, inodes_count);
inode_table_bytes = (inodes_count_total -
((block_group_count - 1) * inodes_per_group)) *
inode_table_item_size;
}
uint32_t inode_table_blocks = inode_table_bytes / block_size;
if (inode_table_bytes % block_size)
inode_table_blocks++;
*goal = inode_table_first_block + inode_table_blocks;
return ext4_fs_put_block_group_ref(&bg_ref);
}
int ext4_balloc_alloc_block(struct ext4_inode_ref *inode_ref, uint32_t *fblock)
{
uint32_t allocated_block = 0;
uint32_t bitmap_block_addr;
uint32_t rel_block_idx = 0;
uint32_t free_blocks;
uint32_t goal;
struct ext4_block bitmap_block;
int rc = ext4_balloc_find_goal(inode_ref, &goal);
if (rc != EOK) {
/* no goal found => partition is full */
return rc;
}
struct ext4_sblock *sb = &inode_ref->fs->sb;
/* Load block group number for goal and relative index */
uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, goal);
uint32_t index_in_group = ext4_fs_baddr2_index_in_group(sb, goal);
/* Load block group reference */
struct ext4_block_group_ref bg_ref;
rc = ext4_fs_get_block_group_ref(inode_ref->fs, block_group, &bg_ref);
if (rc != EOK)
return rc;
free_blocks = ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
if (free_blocks == 0) {
/* This group has no free blocks */
goto goal_failed;
}
/* Compute indexes */
uint32_t first_in_group =
ext4_balloc_get_first_data_block_in_group(sb, &bg_ref);
uint32_t first_in_group_index =
ext4_fs_baddr2_index_in_group(sb, first_in_group);
if (index_in_group < first_in_group_index)
index_in_group = first_in_group_index;
/* Load block with bitmap */
bitmap_block_addr = ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
rc = ext4_block_get(inode_ref->fs->bdev, &bitmap_block, bitmap_block_addr);
if (rc != EOK) {
ext4_fs_put_block_group_ref(&bg_ref);
return rc;
}
/* Check if goal is free */
if (ext4_bmap_is_bit_clr(bitmap_block.data, index_in_group)) {
ext4_bmap_bit_set(bitmap_block.data, index_in_group);
bitmap_block.dirty = true;
rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
if (rc != EOK) {
ext4_fs_put_block_group_ref(&bg_ref);
return rc;
}
allocated_block =
ext4_fs_index_in_group2_baddr(sb, index_in_group, block_group);
goto success;
}
uint32_t blocks_in_group = ext4_blocks_in_group_cnt(sb, block_group);
uint32_t end_idx = (index_in_group + 63) & ~63;
if (end_idx > blocks_in_group)
end_idx = blocks_in_group;
/* Try to find free block near to goal */
uint32_t tmp_idx;
for (tmp_idx = index_in_group + 1; tmp_idx < end_idx; ++tmp_idx) {
if (ext4_bmap_is_bit_clr(bitmap_block.data, tmp_idx)) {
ext4_bmap_bit_set(bitmap_block.data, tmp_idx);
bitmap_block.dirty = true;
rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
if (rc != EOK)
return rc;
allocated_block =
ext4_fs_index_in_group2_baddr(sb, tmp_idx, block_group);
goto success;
}
}
/* Find free bit in bitmap */
rc = ext4_bmap_bit_find_clr(bitmap_block.data, index_in_group,
blocks_in_group, &rel_block_idx);
if (rc == EOK) {
ext4_bmap_bit_set(bitmap_block.data, rel_block_idx);
bitmap_block.dirty = true;
rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
if (rc != EOK)
return rc;
allocated_block =
ext4_fs_index_in_group2_baddr(sb, rel_block_idx, block_group);
goto success;
}
/* No free block found yet */
rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
if (rc != EOK) {
ext4_fs_put_block_group_ref(&bg_ref);
return rc;
}
goal_failed:
rc = ext4_fs_put_block_group_ref(&bg_ref);
if (rc != EOK)
return rc;
/* Try other block groups */
uint32_t block_group_count = ext4_block_group_cnt(sb);
uint32_t bgid = (block_group + 1) % block_group_count;
uint32_t count = block_group_count;
while (count > 0) {
rc = ext4_fs_get_block_group_ref(inode_ref->fs, bgid, &bg_ref);
if (rc != EOK)
return rc;
free_blocks = ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
if (free_blocks == 0) {
/* This group has no free blocks */
goto next_group;
}
/* Load block with bitmap */
bitmap_block_addr = ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
rc = ext4_block_get(inode_ref->fs->bdev, &bitmap_block,
bitmap_block_addr);
if (rc != EOK) {
ext4_fs_put_block_group_ref(&bg_ref);
return rc;
}
/* Compute indexes */
first_in_group = ext4_balloc_get_first_data_block_in_group(sb, &bg_ref);
index_in_group = ext4_fs_baddr2_index_in_group(sb, first_in_group);
blocks_in_group = ext4_blocks_in_group_cnt(sb, bgid);
first_in_group_index =
ext4_fs_baddr2_index_in_group(sb, first_in_group);
if (index_in_group < first_in_group_index)
index_in_group = first_in_group_index;
rc = ext4_bmap_bit_find_clr(bitmap_block.data, index_in_group,
blocks_in_group, &rel_block_idx);
if (rc == EOK) {
ext4_bmap_bit_set(bitmap_block.data, rel_block_idx);
bitmap_block.dirty = true;
rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
if (rc != EOK) {
ext4_fs_put_block_group_ref(&bg_ref);
return rc;
}
allocated_block =
ext4_fs_index_in_group2_baddr(sb, rel_block_idx, bgid);
goto success;
}
rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
if (rc != EOK) {
ext4_fs_put_block_group_ref(&bg_ref);
return rc;
}
next_group:
rc = ext4_fs_put_block_group_ref(&bg_ref);
if (rc != EOK) {
return rc;
}
/* Goto next group */
bgid = (bgid + 1) % block_group_count;
count--;
}
return ENOSPC;
success:
/* Empty command - because of syntax */
;
uint32_t block_size = ext4_sb_get_block_size(sb);
/* Update superblock free blocks count */
uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
sb_free_blocks--;
ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
/* Update inode blocks (different block size!) count */
uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE;
ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
inode_ref->dirty = true;
/* Update block group free blocks count */
uint32_t bg_free_blocks =
ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
bg_free_blocks--;
ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, bg_free_blocks);
bg_ref.dirty = true;
rc = ext4_fs_put_block_group_ref(&bg_ref);
*fblock = allocated_block;
return rc;
}
int ext4_balloc_try_alloc_block(struct ext4_inode_ref *inode_ref,
uint32_t baddr, bool *free)
{
int rc;
struct ext4_fs *fs = inode_ref->fs;
struct ext4_sblock *sb = &fs->sb;
/* Compute indexes */
uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, baddr);
uint32_t index_in_group = ext4_fs_baddr2_index_in_group(sb, baddr);
/* Load block group reference */
struct ext4_block_group_ref bg_ref;
rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
if (rc != EOK)
return rc;
/* Load block with bitmap */
uint32_t bitmap_block_addr =
ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
struct ext4_block bitmap_block;
rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
if (rc != EOK) {
ext4_fs_put_block_group_ref(&bg_ref);
return rc;
}
/* Check if block is free */
*free = ext4_bmap_is_bit_clr(bitmap_block.data, index_in_group);
/* Allocate block if possible */
if (*free) {
ext4_bmap_bit_set(bitmap_block.data, index_in_group);
bitmap_block.dirty = true;
}
/* Release block with bitmap */
rc = ext4_block_set(fs->bdev, &bitmap_block);
if (rc != EOK) {
/* Error in saving bitmap */
ext4_fs_put_block_group_ref(&bg_ref);
return rc;
}
/* If block is not free, return */
if (!(*free))
goto terminate;
uint32_t block_size = ext4_sb_get_block_size(sb);
/* Update superblock free blocks count */
uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
sb_free_blocks--;
ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
/* Update inode blocks count */
uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE;
ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
inode_ref->dirty = true;
/* Update block group free blocks count */
uint32_t free_blocks =
ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
free_blocks--;
ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, free_blocks);
bg_ref.dirty = true;
terminate:
return ext4_fs_put_block_group_ref(&bg_ref);
}
/**
* @}
*/