/*
* 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 libext4
* @{
*/
/**
* @file extent.c
* @brief Ext4 extent structures operations.
*/
#include <byteorder.h>
#include <errno.h>
#include <mem.h>
#include <stdlib.h>
#include "ext4/balloc.h"
#include "ext4/extent.h"
#include "ext4/inode.h"
#include "ext4/superblock.h"
/** Get logical number of the block covered by extent.
*
* @param extent Extent to load number from
*
* @return Logical number of the first block covered by extent
*
*/
uint32_t ext4_extent_get_first_block(ext4_extent_t *extent)
{
return uint32_t_le2host(extent->first_block);
}
/** Set logical number of the first block covered by extent.
*
* @param extent Extent to set number to
* @param iblock Logical number of the first block covered by extent
*
*/
void ext4_extent_set_first_block(ext4_extent_t *extent, uint32_t iblock)
{
extent->first_block = host2uint32_t_le(iblock);
}
/** Get number of blocks covered by extent.
*
* @param extent Extent to load count from
*
* @return Number of blocks covered by extent
*
*/
uint16_t ext4_extent_get_block_count(ext4_extent_t *extent)
{
return uint16_t_le2host(extent->block_count);
}
/** Set number of blocks covered by extent.
*
* @param extent Extent to load count from
* @param count Number of blocks covered by extent
*
*/
void ext4_extent_set_block_count(ext4_extent_t *extent, uint16_t count)
{
extent->block_count = host2uint16_t_le(count);
}
/** Get physical number of the first block covered by extent.
*
* @param extent Extent to load number
*
* @return Physical number of the first block covered by extent
*
*/
uint64_t ext4_extent_get_start(ext4_extent_t *extent)
{
return ((uint64_t)uint16_t_le2host(extent->start_hi)) << 32 |
((uint64_t)uint32_t_le2host(extent->start_lo));
}
/** Set physical number of the first block covered by extent.
*
* @param extent Extent to load number
* @param fblock Physical number of the first block covered by extent
*
*/
void ext4_extent_set_start(ext4_extent_t *extent, uint64_t fblock)
{
extent->start_lo = host2uint32_t_le((fblock << 32) >> 32);
extent->start_hi = host2uint16_t_le((uint16_t)(fblock >> 32));
}
/** Get logical number of the block covered by extent index.
*
* @param index Extent index to load number from
*
* @return Logical number of the first block covered by extent index
*
*/
uint32_t ext4_extent_index_get_first_block(ext4_extent_index_t *index)
{
return uint32_t_le2host(index->first_block);
}
/** Set logical number of the block covered by extent index.
*
* @param index Extent index to set number to
* @param iblock Logical number of the first block covered by extent index
*
*/
void ext4_extent_index_set_first_block(ext4_extent_index_t *index,
uint32_t iblock)
{
index->first_block = host2uint32_t_le(iblock);
}
/** Get physical number of block where the child node is located.
*
* @param index Extent index to load number from
*
* @return Physical number of the block with child node
*
*/
uint64_t ext4_extent_index_get_leaf(ext4_extent_index_t *index)
{
return ((uint64_t) uint16_t_le2host(index->leaf_hi)) << 32 |
((uint64_t)uint32_t_le2host(index->leaf_lo));
}
/** Set physical number of block where the child node is located.
*
* @param index Extent index to set number to
* @param fblock Ohysical number of the block with child node
*
*/
void ext4_extent_index_set_leaf(ext4_extent_index_t *index, uint64_t fblock)
{
index->leaf_lo = host2uint32_t_le((fblock << 32) >> 32);
index->leaf_hi = host2uint16_t_le((uint16_t) (fblock >> 32));
}
/** Get magic value from extent header.
*
* @param header Extent header to load value from
*
* @return Magic value of extent header
*
*/
uint16_t ext4_extent_header_get_magic(ext4_extent_header_t *header)
{
return uint16_t_le2host(header->magic);
}
/** Set magic value to extent header.
*
* @param header Extent header to set value to
* @param magic Magic value of extent header
*
*/
void ext4_extent_header_set_magic(ext4_extent_header_t *header, uint16_t magic)
{
header->magic = host2uint16_t_le(magic);
}
/** Get number of entries from extent header
*
* @param header Extent header to get value from
*
* @return Number of entries covered by extent header
*
*/
uint16_t ext4_extent_header_get_entries_count(ext4_extent_header_t *header)
{
return uint16_t_le2host(header->entries_count);
}
/** Set number of entries to extent header
*
* @param header Extent header to set value to
* @param count Number of entries covered by extent header
*
*/
void ext4_extent_header_set_entries_count(ext4_extent_header_t *header,
uint16_t count)
{
header->entries_count = host2uint16_t_le(count);
}
/** Get maximum number of entries from extent header
*
* @param header Extent header to get value from
*
* @return Maximum number of entries covered by extent header
*
*/
uint16_t ext4_extent_header_get_max_entries_count(ext4_extent_header_t *header)
{
return uint16_t_le2host(header->max_entries_count);
}
/** Set maximum number of entries to extent header
*
* @param header Extent header to set value to
* @param max_count Maximum number of entries covered by extent header
*
*/
void ext4_extent_header_set_max_entries_count(ext4_extent_header_t *header,
uint16_t max_count)
{
header->max_entries_count = host2uint16_t_le(max_count);
}
/** Get depth of extent subtree.
*
* @param header Extent header to get value from
*
* @return Depth of extent subtree
*
*/
uint16_t ext4_extent_header_get_depth(ext4_extent_header_t *header)
{
return uint16_t_le2host(header->depth);
}
/** Set depth of extent subtree.
*
* @param header Extent header to set value to
* @param depth Depth of extent subtree
*
*/
void ext4_extent_header_set_depth(ext4_extent_header_t *header, uint16_t depth)
{
header->depth = host2uint16_t_le(depth);
}
/** Get generation from extent header
*
* @param header Extent header to get value from
*
* @return Generation
*
*/
uint32_t ext4_extent_header_get_generation(ext4_extent_header_t *header)
{
return uint32_t_le2host(header->generation);
}
/** Set generation to extent header
*
* @param header Extent header to set value to
* @param generation Generation
*
*/
void ext4_extent_header_set_generation(ext4_extent_header_t *header,
uint32_t generation)
{
header->generation = host2uint32_t_le(generation);
}
/** Binary search in extent index node.
*
* @param header Extent header of index node
* @param index Output value - found index will be set here
* @param iblock Logical block number to find in index node
*
*/
static void ext4_extent_binsearch_idx(ext4_extent_header_t *header,
ext4_extent_index_t **index, uint32_t iblock)
{
ext4_extent_index_t *r;
ext4_extent_index_t *l;
ext4_extent_index_t *m;
uint16_t entries_count =
ext4_extent_header_get_entries_count(header);
/* Initialize bounds */
l = EXT4_EXTENT_FIRST_INDEX(header) + 1;
r = EXT4_EXTENT_FIRST_INDEX(header) + entries_count - 1;
/* Do binary search */
while (l <= r) {
m = l + (r - l) / 2;
uint32_t first_block = ext4_extent_index_get_first_block(m);
if (iblock < first_block)
r = m - 1;
else
l = m + 1;
}
/* Set output value */
*index = l - 1;
}
/** Binary search in extent leaf node.
*
* @param header Extent header of leaf node
* @param extent Output value - found extent will be set here,
* or NULL if node is empty
* @param iblock Logical block number to find in leaf node
*
*/
static void ext4_extent_binsearch(ext4_extent_header_t *header,
ext4_extent_t **extent, uint32_t iblock)
{
ext4_extent_t *r;
ext4_extent_t *l;
ext4_extent_t *m;
uint16_t entries_count =
ext4_extent_header_get_entries_count(header);
if (entries_count == 0) {
/* this leaf is empty */
*extent = NULL;
return;
}
/* Initialize bounds */
l = EXT4_EXTENT_FIRST(header) + 1;
r = EXT4_EXTENT_FIRST(header) + entries_count - 1;
/* Do binary search */
while (l <= r) {
m = l + (r - l) / 2;
uint32_t first_block = ext4_extent_get_first_block(m);
if (iblock < first_block)
r = m - 1;
else
l = m + 1;
}
/* Set output value */
*extent = l - 1;
}
/** Find physical block in the extent tree by logical block number.
*
* There is no need to save path in the tree during this algorithm.
*
* @param inode_ref I-node to load block from
* @param iblock Logical block number to find
* @param fblock Output value for physical block number
*
* @return Error code
*
*/
errno_t ext4_extent_find_block(ext4_inode_ref_t *inode_ref, uint32_t iblock,
uint32_t *fblock)
{
errno_t rc = EOK;
/* Compute bound defined by i-node size */
uint64_t inode_size =
ext4_inode_get_size(inode_ref->fs->superblock, inode_ref->inode);
uint32_t block_size =
ext4_superblock_get_block_size(inode_ref->fs->superblock);
uint32_t last_idx = (inode_size - 1) / block_size;
/* Check if requested iblock is not over size of i-node */
if (iblock > last_idx) {
*fblock = 0;
return EOK;
}
block_t *block = NULL;
/* Walk through extent tree */
ext4_extent_header_t *header =
ext4_inode_get_extent_header(inode_ref->inode);
while (ext4_extent_header_get_depth(header) != 0) {
/* Search index in node */
ext4_extent_index_t *index;
ext4_extent_binsearch_idx(header, &index, iblock);
/* Load child node and set values for the next iteration */
uint64_t child = ext4_extent_index_get_leaf(index);
if (block != NULL) {
rc = block_put(block);
if (rc != EOK)
return rc;
}
rc = block_get(&block, inode_ref->fs->device, child,
BLOCK_FLAGS_NONE);
if (rc != EOK)
return rc;
header = (ext4_extent_header_t *)block->data;
}
/* Search extent in the leaf block */
ext4_extent_t *extent = NULL;
ext4_extent_binsearch(header, &extent, iblock);
/* Prevent empty leaf */
if (extent == NULL) {
*fblock = 0;
} else {
/* Compute requested physical block address */
uint32_t phys_block;
uint32_t first = ext4_extent_get_first_block(extent);
phys_block = ext4_extent_get_start(extent) + iblock - first;
*fblock = phys_block;
}
/* Cleanup */
if (block != NULL)
rc = block_put(block);
return rc;
}
/** Find extent for specified iblock.
*
* This function is used for finding block in the extent tree with
* saving the path through the tree for possible future modifications.
*
* @param inode_ref I-node to read extent tree from
* @param iblock Iblock to find extent for
* @param ret_path Output value for loaded path from extent tree
*
* @return Error code
*
*/
static errno_t ext4_extent_find_extent(ext4_inode_ref_t *inode_ref, uint32_t iblock,
ext4_extent_path_t **ret_path)
{
ext4_extent_header_t *eh =
ext4_inode_get_extent_header(inode_ref->inode);
uint16_t depth = ext4_extent_header_get_depth(eh);
ext4_extent_path_t *tmp_path;
/* Added 2 for possible tree growing */
tmp_path = malloc(sizeof(ext4_extent_path_t) * (depth + 2));
if (tmp_path == NULL)
return ENOMEM;
/* Initialize structure for algorithm start */
tmp_path[0].block = inode_ref->block;
tmp_path[0].header = eh;
/* Walk through the extent tree */
uint16_t pos = 0;
errno_t rc;
errno_t rc2;
while (ext4_extent_header_get_depth(eh) != 0) {
/* Search index in index node by iblock */
ext4_extent_binsearch_idx(tmp_path[pos].header,
&tmp_path[pos].index, iblock);
tmp_path[pos].depth = depth;
tmp_path[pos].extent = NULL;
assert(tmp_path[pos].index != NULL);
/* Load information for the next iteration */
uint64_t fblock = ext4_extent_index_get_leaf(tmp_path[pos].index);
block_t *block;
rc = block_get(&block, inode_ref->fs->device, fblock,
BLOCK_FLAGS_NONE);
if (rc != EOK)
goto cleanup;
pos++;
eh = (ext4_extent_header_t *)block->data;
tmp_path[pos].block = block;
tmp_path[pos].header = eh;
}
tmp_path[pos].depth = 0;
tmp_path[pos].extent = NULL;
tmp_path[pos].index = NULL;
/* Find extent in the leaf node */
ext4_extent_binsearch(tmp_path[pos].header, &tmp_path[pos].extent, iblock);
*ret_path = tmp_path;
return EOK;
cleanup:
rc2 = EOK;
/*
* Put loaded blocks
* From 1: 0 is a block with inode data
*/
for (uint16_t i = 1; i < tmp_path->depth; ++i) {
if (tmp_path[i].block) {
rc2 = block_put(tmp_path[i].block);
if (rc == EOK && rc2 != EOK)
rc = rc2;
}
}
/* Destroy temporary data structure */
free(tmp_path);
return rc;
}
/** Release extent and all data blocks covered by the extent.
*
* @param inode_ref I-node to release extent and block from
* @param extent Extent to release
*
* @return Error code
*
*/
static errno_t ext4_extent_release(ext4_inode_ref_t *inode_ref,
ext4_extent_t *extent)
{
/* Compute number of the first physical block to release */
uint64_t start = ext4_extent_get_start(extent);
uint16_t block_count = ext4_extent_get_block_count(extent);
return ext4_balloc_free_blocks(inode_ref, start, block_count);
}
/** Recursively release the whole branch of the extent tree.
*
* For each entry of the node release the subbranch and finally release
* the node. In the leaf node all extents will be released.
*
* @param inode_ref I-node where the branch is released
* @param index Index in the non-leaf node to be released
* with the whole subtree
*
* @return Error code
*
*/
static errno_t ext4_extent_release_branch(ext4_inode_ref_t *inode_ref,
ext4_extent_index_t *index)
{
uint32_t fblock = ext4_extent_index_get_leaf(index);
block_t *block;
errno_t rc = block_get(&block, inode_ref->fs->device, fblock, BLOCK_FLAGS_NONE);
if (rc != EOK)
return rc;
ext4_extent_header_t *header = block->data;
if (ext4_extent_header_get_depth(header)) {
/* The node is non-leaf, do recursion */
ext4_extent_index_t *idx = EXT4_EXTENT_FIRST_INDEX(header);
/* Release all subbranches */
for (uint32_t i = 0;
i < ext4_extent_header_get_entries_count(header);
++i, ++idx) {
rc = ext4_extent_release_branch(inode_ref, idx);
if (rc != EOK)
return rc;
}
} else {
/* Leaf node reached */
ext4_extent_t *ext = EXT4_EXTENT_FIRST(header);
/* Release all extents and stop recursion */
for (uint32_t i = 0;
i < ext4_extent_header_get_entries_count(header);
++i, ++ext) {
rc = ext4_extent_release(inode_ref, ext);
if (rc != EOK)
return rc;
}
}
/* Release data block where the node was stored */
rc = block_put(block);
if (rc != EOK)
return rc;
return ext4_balloc_free_block(inode_ref, fblock);
}
/** Release all data blocks starting from specified logical block.
*
* @param inode_ref I-node to release blocks from
* @param iblock_from First logical block to release
*
*/
errno_t ext4_extent_release_blocks_from(ext4_inode_ref_t *inode_ref,
uint32_t iblock_from)
{
/* Find the first extent to modify */
ext4_extent_path_t *path;
errno_t rc2;
errno_t rc = ext4_extent_find_extent(inode_ref, iblock_from, &path);
if (rc != EOK)
return rc;
/* Jump to last item of the path (extent) */
ext4_extent_path_t *path_ptr = path;
while (path_ptr->depth != 0)
path_ptr++;
assert(path_ptr->extent != NULL);
/* First extent maybe released partially */
uint32_t first_iblock =
ext4_extent_get_first_block(path_ptr->extent);
uint32_t first_fblock =
ext4_extent_get_start(path_ptr->extent) + iblock_from - first_iblock;
uint16_t block_count = ext4_extent_get_block_count(path_ptr->extent);
uint16_t delete_count = block_count -
(first_fblock - ext4_extent_get_start(path_ptr->extent));
/* Release all blocks */
rc = ext4_balloc_free_blocks(inode_ref, first_fblock, delete_count);
if (rc != EOK)
goto cleanup;
/* Correct counter */
block_count -= delete_count;
ext4_extent_set_block_count(path_ptr->extent, block_count);
/* Initialize the following loop */
uint16_t entries =
ext4_extent_header_get_entries_count(path_ptr->header);
ext4_extent_t *tmp_ext = path_ptr->extent + 1;
ext4_extent_t *stop_ext = EXT4_EXTENT_FIRST(path_ptr->header) + entries;
/* If first extent empty, release it */
if (block_count == 0)
entries--;
/* Release all successors of the first extent in the same node */
while (tmp_ext < stop_ext) {
first_fblock = ext4_extent_get_start(tmp_ext);
delete_count = ext4_extent_get_block_count(tmp_ext);
rc = ext4_balloc_free_blocks(inode_ref, first_fblock, delete_count);
if (rc != EOK)
goto cleanup;
entries--;
tmp_ext++;
}
ext4_extent_header_set_entries_count(path_ptr->header, entries);
path_ptr->block->dirty = true;
/* If leaf node is empty, parent entry must be modified */
bool remove_parent_record = false;
/* Don't release root block (including inode data) !!! */
if ((path_ptr != path) && (entries == 0)) {
rc = ext4_balloc_free_block(inode_ref, path_ptr->block->lba);
if (rc != EOK)
goto cleanup;
remove_parent_record = true;
}
/* Jump to the parent */
--path_ptr;
/* Release all successors in all tree levels */
while (path_ptr >= path) {
entries = ext4_extent_header_get_entries_count(path_ptr->header);
ext4_extent_index_t *index = path_ptr->index + 1;
ext4_extent_index_t *stop =
EXT4_EXTENT_FIRST_INDEX(path_ptr->header) + entries;
/* Correct entries count because of changes in the previous iteration */
if (remove_parent_record)
entries--;
/* Iterate over all entries and release the whole subtrees */
while (index < stop) {
rc = ext4_extent_release_branch(inode_ref, index);
if (rc != EOK)
goto cleanup;
++index;
--entries;
}
ext4_extent_header_set_entries_count(path_ptr->header, entries);
path_ptr->block->dirty = true;
/* Free the node if it is empty */
if ((entries == 0) && (path_ptr != path)) {
rc = ext4_balloc_free_block(inode_ref, path_ptr->block->lba);
if (rc != EOK)
goto cleanup;
/* Mark parent to be checked */
remove_parent_record = true;
} else
remove_parent_record = false;
--path_ptr;
}
cleanup:
rc2 = EOK;
/*
* Put loaded blocks
* starting from 1: 0 is a block with inode data
*/
for (uint16_t i = 1; i <= path->depth; ++i) {
if (path[i].block) {
rc2 = block_put(path[i].block);
if (rc == EOK && rc2 != EOK)
rc = rc2;
}
}
/* Destroy temporary data structure */
free(path);
return rc;
}
/** Append new extent to the i-node and do some splitting if necessary.
*
* @param inode_ref I-node to append extent to
* @param path Path in the extent tree for possible splitting
* @param last_path_item Input/output parameter for pointer to the last
* valid item in the extent tree path
* @param iblock Logical index of block to append extent for
*
* @return Error code
*
*/
static errno_t ext4_extent_append_extent(ext4_inode_ref_t *inode_ref,
ext4_extent_path_t *path, uint32_t iblock)
{
ext4_extent_path_t *path_ptr = path + path->depth;
uint32_t block_size =
ext4_superblock_get_block_size(inode_ref->fs->superblock);
/* Start splitting */
while (path_ptr > path) {
uint16_t entries =
ext4_extent_header_get_entries_count(path_ptr->header);
uint16_t limit =
ext4_extent_header_get_max_entries_count(path_ptr->header);
if (entries == limit) {
/* Full node - allocate block for new one */
uint32_t fblock;
errno_t rc = ext4_balloc_alloc_block(inode_ref, &fblock);
if (rc != EOK)
return rc;
block_t *block;
rc = block_get(&block, inode_ref->fs->device, fblock,
BLOCK_FLAGS_NOREAD);
if (rc != EOK) {
ext4_balloc_free_block(inode_ref, fblock);
return rc;
}
/* Put back not modified old block */
rc = block_put(path_ptr->block);
if (rc != EOK) {
ext4_balloc_free_block(inode_ref, fblock);
block_put(block);
return rc;
}
/* Initialize newly allocated block and remember it */
memset(block->data, 0, block_size);
path_ptr->block = block;
/* Update pointers in extent path structure */
path_ptr->header = block->data;
if (path_ptr->depth) {
path_ptr->index = EXT4_EXTENT_FIRST_INDEX(path_ptr->header);
ext4_extent_index_set_first_block(path_ptr->index, iblock);
ext4_extent_index_set_leaf(path_ptr->index, (path_ptr + 1)->block->lba);
limit = (block_size - sizeof(ext4_extent_header_t)) /
sizeof(ext4_extent_index_t);
} else {
path_ptr->extent = EXT4_EXTENT_FIRST(path_ptr->header);
ext4_extent_set_first_block(path_ptr->extent, iblock);
limit = (block_size - sizeof(ext4_extent_header_t)) /
sizeof(ext4_extent_t);
}
/* Initialize on-disk structure (header) */
ext4_extent_header_set_entries_count(path_ptr->header, 1);
ext4_extent_header_set_max_entries_count(path_ptr->header, limit);
ext4_extent_header_set_magic(path_ptr->header, EXT4_EXTENT_MAGIC);
ext4_extent_header_set_depth(path_ptr->header, path_ptr->depth);
ext4_extent_header_set_generation(path_ptr->header, 0);
path_ptr->block->dirty = true;
/* Jump to the preceeding item */
path_ptr--;
} else {
/* Node with free space */
if (path_ptr->depth) {
path_ptr->index = EXT4_EXTENT_FIRST_INDEX(path_ptr->header) + entries;
ext4_extent_index_set_first_block(path_ptr->index, iblock);
ext4_extent_index_set_leaf(path_ptr->index, (path_ptr + 1)->block->lba);
} else {
path_ptr->extent = EXT4_EXTENT_FIRST(path_ptr->header) + entries;
ext4_extent_set_first_block(path_ptr->extent, iblock);
}
ext4_extent_header_set_entries_count(path_ptr->header, entries + 1);
path_ptr->block->dirty = true;
/* No more splitting needed */
return EOK;
}
}
assert(path_ptr == path);
/* Should be the root split too? */
uint16_t entries = ext4_extent_header_get_entries_count(path->header);
uint16_t limit = ext4_extent_header_get_max_entries_count(path->header);
if (entries == limit) {
uint32_t new_fblock;
errno_t rc = ext4_balloc_alloc_block(inode_ref, &new_fblock);
if (rc != EOK)
return rc;
block_t *block;
rc = block_get(&block, inode_ref->fs->device, new_fblock,
BLOCK_FLAGS_NOREAD);
if (rc != EOK)
return rc;
/* Initialize newly allocated block */
memset(block->data, 0, block_size);
/* Move data from root to the new block */
memcpy(block->data, inode_ref->inode->blocks,
EXT4_INODE_BLOCKS * sizeof(uint32_t));
/* Data block is initialized */
block_t *root_block = path->block;
uint16_t root_depth = path->depth;
ext4_extent_header_t *root_header = path->header;
/* Make space for tree growing */
ext4_extent_path_t *new_root = path;
ext4_extent_path_t *old_root = path + 1;
size_t nbytes = sizeof(ext4_extent_path_t) * (path->depth + 1);
memmove(old_root, new_root, nbytes);
memset(new_root, 0, sizeof(ext4_extent_path_t));
/* Update old root structure */
old_root->block = block;
old_root->header = (ext4_extent_header_t *)block->data;
/* Add new entry and update limit for entries */
if (old_root->depth) {
limit = (block_size - sizeof(ext4_extent_header_t)) /
sizeof(ext4_extent_index_t);
old_root->index = EXT4_EXTENT_FIRST_INDEX(old_root->header) + entries;
ext4_extent_index_set_first_block(old_root->index, iblock);
ext4_extent_index_set_leaf(old_root->index, (old_root + 1)->block->lba);
old_root->extent = NULL;
} else {
limit = (block_size - sizeof(ext4_extent_header_t)) /
sizeof(ext4_extent_t);
old_root->extent = EXT4_EXTENT_FIRST(old_root->header) + entries;
ext4_extent_set_first_block(old_root->extent, iblock);
old_root->index = NULL;
}
ext4_extent_header_set_entries_count(old_root->header, entries + 1);
ext4_extent_header_set_max_entries_count(old_root->header, limit);
old_root->block->dirty = true;
/* Re-initialize new root metadata */
new_root->depth = root_depth + 1;
new_root->block = root_block;
new_root->header = root_header;
new_root->extent = NULL;
new_root->index = EXT4_EXTENT_FIRST_INDEX(new_root->header);
ext4_extent_header_set_depth(new_root->header, new_root->depth);
/* Create new entry in root */
ext4_extent_header_set_entries_count(new_root->header, 1);
ext4_extent_index_set_first_block(new_root->index, 0);
ext4_extent_index_set_leaf(new_root->index, new_fblock);
new_root->block->dirty = true;
} else {
if (path->depth) {
path->index = EXT4_EXTENT_FIRST_INDEX(path->header) + entries;
ext4_extent_index_set_first_block(path->index, iblock);
ext4_extent_index_set_leaf(path->index, (path + 1)->block->lba);
} else {
path->extent = EXT4_EXTENT_FIRST(path->header) + entries;
ext4_extent_set_first_block(path->extent, iblock);
}
ext4_extent_header_set_entries_count(path->header, entries + 1);
path->block->dirty = true;
}
return EOK;
}
/** Append data block to the i-node.
*
* This function allocates data block, tries to append it
* to some existing extent or creates new extents.
* It includes possible extent tree modifications (splitting).
*
* @param inode_ref I-node to append block to
* @param iblock Output logical number of newly allocated block
* @param fblock Output physical block address of newly allocated block
*
* @return Error code
*
*/
errno_t ext4_extent_append_block(ext4_inode_ref_t *inode_ref, uint32_t *iblock,
uint32_t *fblock, bool update_size)
{
ext4_superblock_t *sb = inode_ref->fs->superblock;
uint64_t inode_size = ext4_inode_get_size(sb, inode_ref->inode);
uint32_t block_size = ext4_superblock_get_block_size(sb);
/* Calculate number of new logical block */
uint32_t new_block_idx = 0;
if (inode_size > 0) {
if ((inode_size % block_size) != 0)
inode_size += block_size - (inode_size % block_size);
new_block_idx = inode_size / block_size;
}
/* Load the nearest leaf (with extent) */
ext4_extent_path_t *path;
errno_t rc2;
errno_t rc = ext4_extent_find_extent(inode_ref, new_block_idx, &path);
if (rc != EOK)
return rc;
/* Jump to last item of the path (extent) */
ext4_extent_path_t *path_ptr = path;
while (path_ptr->depth != 0)
path_ptr++;
/* Add new extent to the node if not present */
if (path_ptr->extent == NULL)
goto append_extent;
uint16_t block_count = ext4_extent_get_block_count(path_ptr->extent);
uint16_t block_limit = (1 << 15);
uint32_t phys_block = 0;
if (block_count < block_limit) {
/* There is space for new block in the extent */
if (block_count == 0) {
/* Existing extent is empty */
rc = ext4_balloc_alloc_block(inode_ref, &phys_block);
if (rc != EOK)
goto finish;
/* Initialize extent */
ext4_extent_set_first_block(path_ptr->extent, new_block_idx);
ext4_extent_set_start(path_ptr->extent, phys_block);
ext4_extent_set_block_count(path_ptr->extent, 1);
/* Update i-node */
if (update_size) {
ext4_inode_set_size(inode_ref->inode, inode_size + block_size);
inode_ref->dirty = true;
}
path_ptr->block->dirty = true;
goto finish;
} else {
/* Existing extent contains some blocks */
phys_block = ext4_extent_get_start(path_ptr->extent);
phys_block += ext4_extent_get_block_count(path_ptr->extent);
/* Check if the following block is free for allocation */
bool free;
rc = ext4_balloc_try_alloc_block(inode_ref, phys_block, &free);
if (rc != EOK)
goto finish;
if (!free) {
/* Target is not free, new block must be appended to new extent */
goto append_extent;
}
/* Update extent */
ext4_extent_set_block_count(path_ptr->extent, block_count + 1);
/* Update i-node */
if (update_size) {
ext4_inode_set_size(inode_ref->inode, inode_size + block_size);
inode_ref->dirty = true;
}
path_ptr->block->dirty = true;
goto finish;
}
}
append_extent:
/* Append new extent to the tree */
phys_block = 0;
/* Allocate new data block */
rc = ext4_balloc_alloc_block(inode_ref, &phys_block);
if (rc != EOK)
goto finish;
/* Append extent for new block (includes tree splitting if needed) */
rc = ext4_extent_append_extent(inode_ref, path, new_block_idx);
if (rc != EOK) {
ext4_balloc_free_block(inode_ref, phys_block);
goto finish;
}
uint32_t tree_depth = ext4_extent_header_get_depth(path->header);
path_ptr = path + tree_depth;
/* Initialize newly created extent */
ext4_extent_set_block_count(path_ptr->extent, 1);
ext4_extent_set_first_block(path_ptr->extent, new_block_idx);
ext4_extent_set_start(path_ptr->extent, phys_block);
/* Update i-node */
if (update_size) {
ext4_inode_set_size(inode_ref->inode, inode_size + block_size);
inode_ref->dirty = true;
}
path_ptr->block->dirty = true;
finish:
rc2 = EOK;
/* Set return values */
*iblock = new_block_idx;
*fblock = phys_block;
/*
* Put loaded blocks
* starting from 1: 0 is a block with inode data
*/
for (uint16_t i = 1; i <= path->depth; ++i) {
if (path[i].block) {
rc2 = block_put(path[i].block);
if (rc == EOK && rc2 != EOK)
rc = rc2;
}
}
/* Destroy temporary data structure */
free(path);
return rc;
}
/**
* @}
*/