ref: 5dfdaf27ae4bdfab84d4853612b21e460fbd1c75
dir: /lwext4/ext4_extent.c/
/*
* Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)
*
*
* 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_extent.c
* @brief More complex filesystem functions.
*/
#include "ext4_config.h"
#include "ext4_extent.h"
#include "ext4_inode.h"
#include "ext4_super.h"
#include "ext4_crc32c.h"
#include "ext4_blockdev.h"
#include "ext4_balloc.h"
#include "ext4_fs.h"
#include <string.h>
#include <stdlib.h>
#if !CONFIG_EXTENT_FULL
static struct ext4_extent_header *ext_inode_hdr(struct ext4_inode *inode)
{
return (struct ext4_extent_header *)inode->blocks;
}
static uint16_t ext_depth(struct ext4_inode *inode)
{
return to_le16(ext_inode_hdr(inode)->depth);
}
static struct ext4_extent_tail *
find_ext4_extent_tail(struct ext4_extent_header *eh)
{
return (struct ext4_extent_tail *)(((char *)eh) +
EXT4_EXTENT_TAIL_OFFSET(eh));
}
#if CONFIG_META_CSUM_ENABLE
static uint32_t ext4_ext_block_csum(struct ext4_inode_ref *inode_ref,
struct ext4_extent_header *eh)
{
uint32_t checksum = 0;
struct ext4_sblock *sb = &inode_ref->fs->sb;
if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
uint32_t ino_index = to_le32(inode_ref->index);
uint32_t ino_gen =
to_le32(ext4_inode_get_generation(inode_ref->inode));
/* First calculate crc32 checksum against fs uuid */
checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
sizeof(sb->uuid));
/* Then calculate crc32 checksum against inode number
* and inode generation */
checksum = ext4_crc32c(checksum, &ino_index,
sizeof(ino_index));
checksum = ext4_crc32c(checksum, &ino_gen,
sizeof(ino_gen));
/* Finally calculate crc32 checksum against
* the entire extent block up to the checksum field */
checksum = ext4_crc32c(checksum, eh,
EXT4_EXTENT_TAIL_OFFSET(eh));
}
return checksum;
}
#else
#define ext4_ext_block_csum(...) 0
#endif
static void ext4_extent_block_csum_set(struct ext4_inode_ref *inode_ref,
struct ext4_extent_header *eh)
{
struct ext4_extent_tail *tail;
if (!ext4_sb_feature_ro_com(&inode_ref->fs->sb,
EXT4_FRO_COM_METADATA_CSUM))
return;
if (to_le16(eh->depth) < ext_depth(inode_ref->inode)) {
tail = find_ext4_extent_tail(eh);
tail->et_checksum = to_le32(ext4_ext_block_csum(inode_ref, eh));
}
}
#if CONFIG_META_CSUM_ENABLE
static bool
ext4_extent_verify_block_csum(struct ext4_inode_ref *inode_ref,
struct ext4_block *block)
{
struct ext4_extent_header *eh;
struct ext4_extent_tail *tail;
eh = (struct ext4_extent_header *)block->data;
if (!ext4_sb_feature_ro_com(&inode_ref->fs->sb,
EXT4_FRO_COM_METADATA_CSUM))
return true;
if (to_le16(eh->depth) < ext_depth(inode_ref->inode)) {
tail = find_ext4_extent_tail(eh);
return tail->et_checksum ==
to_le32(ext4_ext_block_csum(inode_ref, eh));
}
return true;
}
#else
#define ext4_extent_verify_block_csum(...) true
#endif
/**@brief 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(struct ext4_extent_header *header,
struct ext4_extent_index **index,
uint32_t iblock)
{
struct ext4_extent_index *r;
struct ext4_extent_index *l;
struct ext4_extent_index *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;
}
/**@brief 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(struct ext4_extent_header *header,
struct ext4_extent **extent, uint32_t iblock)
{
struct ext4_extent *r;
struct ext4_extent *l;
struct ext4_extent *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;
}
/**@brief Get 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*/
static int
ext4_extent_find_block(struct ext4_inode_ref *inode_ref, uint32_t iblock,
ext4_fsblk_t *fblock)
{
int rc;
/* Compute bound defined by i-node size */
uint64_t inode_size =
ext4_inode_get_size(&inode_ref->fs->sb, inode_ref->inode);
uint32_t block_size = ext4_sb_get_block_size(&inode_ref->fs->sb);
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;
}
struct ext4_block block;
block.lb_id = 0;
/* Walk through extent tree */
struct ext4_extent_header *header =
ext4_inode_get_extent_header(inode_ref->inode);
while (ext4_extent_header_get_depth(header) != 0) {
/* Search index in node */
struct ext4_extent_index *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.lb_id) {
rc = ext4_block_set(inode_ref->fs->bdev, &block);
if (rc != EOK)
return rc;
}
int rc = ext4_block_get(inode_ref->fs->bdev, &block, child);
if (rc != EOK)
return rc;
if (!ext4_extent_verify_block_csum(inode_ref,
&block)) {
ext4_dbg(DEBUG_EXTENT,
DBG_WARN "Extent block checksum failed."
"Blocknr: %" PRIu64"\n",
child);
}
header = (struct ext4_extent_header *)block.data;
}
/* Search extent in the leaf block */
struct ext4_extent *extent = NULL;
ext4_extent_binsearch(header, &extent, iblock);
/* Prevent empty leaf */
if (extent == NULL) {
*fblock = 0;
} else {
/* Compute requested physical block address */
ext4_fsblk_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.lb_id) {
rc = ext4_block_set(inode_ref->fs->bdev, &block);
if (rc != EOK)
return rc;
}
return EOK;
}
/**@brief 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 int ext4_extent_find_extent(struct ext4_inode_ref *inode_ref,
uint32_t iblock,
struct ext4_extent_path **ret_path)
{
struct ext4_extent_header *eh =
ext4_inode_get_extent_header(inode_ref->inode);
uint16_t depth = ext4_extent_header_get_depth(eh);
uint16_t i;
struct ext4_extent_path *tmp_path;
/* Added 2 for possible tree growing */
tmp_path = malloc(sizeof(struct ext4_extent_path) * (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;
int rc;
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;
ext4_assert(tmp_path[pos].index != 0);
/* Load information for the next iteration */
uint64_t fblock =
ext4_extent_index_get_leaf(tmp_path[pos].index);
struct ext4_block block;
rc = ext4_block_get(inode_ref->fs->bdev, &block, fblock);
if (rc != EOK)
goto cleanup;
if (!ext4_extent_verify_block_csum(inode_ref,
&block)) {
ext4_dbg(DEBUG_EXTENT,
DBG_WARN "Extent block checksum failed."
"Blocknr: %" PRIu64"\n",
fblock);
}
pos++;
eh = (struct ext4_extent_header *)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:
/*
* Put loaded blocks
* From 1: 0 is a block with inode data
*/
for (i = 1; i < tmp_path->depth; ++i) {
if (tmp_path[i].block.lb_id) {
int r = ext4_block_set(inode_ref->fs->bdev,
&tmp_path[i].block);
if (r != EOK)
rc = r;
}
}
/* Destroy temporary data structure */
free(tmp_path);
return rc;
}
/**@brief 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 int ext4_extent_release(struct ext4_inode_ref *inode_ref,
struct ext4_extent *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 int ext4_extent_release_branch(struct ext4_inode_ref *inode_ref,
struct ext4_extent_index *index)
{
ext4_fsblk_t fblock = ext4_extent_index_get_leaf(index);
uint32_t i;
struct ext4_block block;
int rc = ext4_block_get(inode_ref->fs->bdev, &block, fblock);
if (rc != EOK)
return rc;
if (!ext4_extent_verify_block_csum(inode_ref,
&block)) {
ext4_dbg(DEBUG_EXTENT,
DBG_WARN "Extent block checksum failed."
"Blocknr: %" PRIu64"\n",
fblock);
}
struct ext4_extent_header *header = (void *)block.data;
if (ext4_extent_header_get_depth(header)) {
/* The node is non-leaf, do recursion */
struct ext4_extent_index *idx = EXT4_EXTENT_FIRST_INDEX(header);
/* Release all subbranches */
for (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 */
struct ext4_extent *ext = EXT4_EXTENT_FIRST(header);
/* Release all extents and stop recursion */
for (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 = ext4_block_set(inode_ref->fs->bdev, &block);
if (rc != EOK)
return rc;
return ext4_balloc_free_block(inode_ref, fblock);
}
int ext4_extent_remove_space(struct ext4_inode_ref *inode_ref, ext4_lblk_t from,
ext4_lblk_t to)
{
if (to != EXT_MAX_BLOCKS)
return ENOTSUP;
/* Find the first extent to modify */
struct ext4_extent_path *path;
uint16_t i;
int rc = ext4_extent_find_extent(inode_ref, from, &path);
if (rc != EOK)
return rc;
/* Jump to last item of the path (extent) */
struct ext4_extent_path *path_ptr = path;
while (path_ptr->depth != 0)
path_ptr++;
ext4_assert(path_ptr->extent != NULL);
/* First extent maybe released partially */
uint32_t first_iblock = ext4_extent_get_first_block(path_ptr->extent);
ext4_fsblk_t first_fblock = ext4_extent_get_start(path_ptr->extent) +
from - first_iblock;
uint16_t block_count = ext4_extent_get_block_count(path_ptr->extent);
uint16_t delete_count =
block_count -
(ext4_extent_get_start(path_ptr->extent) - first_fblock);
/* 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,
EXT4_EXT_IS_UNWRITTEN(path_ptr->extent));
/* Initialize the following loop */
uint16_t entries =
ext4_extent_header_get_entries_count(path_ptr->header);
struct ext4_extent *tmp_ext = path_ptr->extent + 1;
struct ext4_extent *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);
ext4_extent_block_csum_set(inode_ref, path_ptr->header);
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.lb_id);
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);
struct ext4_extent_index *index = path_ptr->index + 1;
struct ext4_extent_index *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);
ext4_extent_block_csum_set(inode_ref, path_ptr->header);
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.lb_id);
if (rc != EOK)
goto cleanup;
/* Mark parent to be checked */
remove_parent_record = true;
} else
remove_parent_record = false;
--path_ptr;
}
if (!entries)
ext4_extent_header_set_depth(path->header, 0);
cleanup:
/*
* Put loaded blocks
* starting from 1: 0 is a block with inode data
*/
for (i = 1; i <= path->depth; ++i) {
if (path[i].block.lb_id) {
int r =
ext4_block_set(inode_ref->fs->bdev, &path[i].block);
if (r != EOK)
rc = r;
}
}
/* Destroy temporary data structure */
free(path);
return rc;
}
/**@brief 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 int ext4_extent_append_extent(struct ext4_inode_ref *inode_ref,
struct ext4_extent_path *path,
uint32_t iblock)
{
struct ext4_extent_path *path_ptr = path + path->depth;
uint32_t block_size = ext4_sb_get_block_size(&inode_ref->fs->sb);
/* 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 */
ext4_fsblk_t goal, fblock;
int rc = ext4_fs_indirect_find_goal(inode_ref, &goal);
if (rc != EOK)
return rc;
rc = ext4_balloc_alloc_block(inode_ref, goal, &fblock);
if (rc != EOK)
return rc;
struct ext4_block block;
rc =
ext4_block_get_noread(inode_ref->fs->bdev, &block, fblock);
if (rc != EOK) {
ext4_balloc_free_block(inode_ref, fblock);
return rc;
}
/* Put back not modified old block */
rc = ext4_block_set(inode_ref->fs->bdev,
&path_ptr->block);
if (rc != EOK) {
ext4_balloc_free_block(inode_ref, fblock);
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 = (void *)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.lb_id);
limit = (block_size -
sizeof(struct ext4_extent_header)) /
sizeof(struct ext4_extent_index);
} else {
path_ptr->extent =
EXT4_EXTENT_FIRST(path_ptr->header);
ext4_extent_set_first_block(path_ptr->extent,
iblock);
limit = (block_size -
sizeof(struct ext4_extent_header)) /
sizeof(struct ext4_extent);
}
/* 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);
ext4_extent_block_csum_set(inode_ref, path_ptr->header);
path_ptr->block.dirty = true;
/* Jump to the preceding 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.lb_id);
} 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);
ext4_extent_block_csum_set(inode_ref, path_ptr->header);
path_ptr->block.dirty = true;
/* No more splitting needed */
return EOK;
}
}
ext4_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) {
ext4_fsblk_t goal, new_fblock;
int rc = ext4_fs_indirect_find_goal(inode_ref, &goal);
if (rc != EOK)
return rc;
rc = ext4_balloc_alloc_block(inode_ref, goal, &new_fblock);
if (rc != EOK)
return rc;
struct ext4_block block;
rc = ext4_block_get_noread(inode_ref->fs->bdev, &block, new_fblock);
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 */
struct ext4_block *root_block = &path->block;
uint16_t root_depth = path->depth;
struct ext4_extent_header *root_header = path->header;
/* Make space for tree growing */
struct ext4_extent_path *new_root = path;
struct ext4_extent_path *old_root = path + 1;
size_t nbytes =
sizeof(struct ext4_extent_path) * (path->depth + 1);
memmove(old_root, new_root, nbytes);
memset(new_root, 0, sizeof(struct ext4_extent_path));
/* Update old root structure */
old_root->block = block;
old_root->header = (struct ext4_extent_header *)block.data;
/* Add new entry and update limit for entries */
if (old_root->depth) {
limit =
(block_size - sizeof(struct ext4_extent_header)) /
sizeof(struct ext4_extent_index);
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.lb_id);
old_root->extent = NULL;
} else {
limit =
(block_size - sizeof(struct ext4_extent_header)) /
sizeof(struct ext4_extent);
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);
ext4_extent_block_csum_set(inode_ref, old_root->header);
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);
/* Since new_root belongs to on-disk inode,
* we don't do checksum here */
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.lb_id);
} 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);
/* Since new_root belongs to on-disk inode,
* we don't do checksum here */
path->block.dirty = true;
}
return EOK;
}
/**@brief 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*/
static int
ext4_extent_append_block(struct ext4_inode_ref *inode_ref, uint32_t *iblock,
ext4_fsblk_t *fblock, bool update_size)
{
uint16_t i;
ext4_fsblk_t goal;
struct ext4_sblock *sb = &inode_ref->fs->sb;
uint64_t inode_size = ext4_inode_get_size(sb, inode_ref->inode);
uint32_t block_size = ext4_sb_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) */
struct ext4_extent_path *path;
int rc = ext4_extent_find_extent(inode_ref, new_block_idx, &path);
if (rc != EOK)
return rc;
/* Jump to last item of the path (extent) */
struct ext4_extent_path *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);
ext4_fsblk_t phys_block = 0;
if (block_count < block_limit) {
/* There is space for new block in the extent */
if (block_count == 0) {
int rc = ext4_fs_indirect_find_goal(inode_ref, &goal);
if (rc != EOK)
goto finish;
/* Existing extent is empty */
rc = ext4_balloc_alloc_block(inode_ref, goal, &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,
false);
/* Update i-node */
if (update_size) {
ext4_inode_set_size(inode_ref->inode,
inode_size + block_size);
inode_ref->dirty = true;
}
ext4_extent_block_csum_set(inode_ref, path_ptr->header);
path_ptr->block.dirty = true;
goto finish;
} else {
ext4_fsblk_t goal;
int rc = ext4_fs_indirect_find_goal(inode_ref, &goal);
if (rc != EOK)
goto finish;
/* 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,
false);
/* Update i-node */
if (update_size) {
ext4_inode_set_size(inode_ref->inode,
inode_size + block_size);
inode_ref->dirty = true;
}
ext4_extent_block_csum_set(inode_ref, path_ptr->header);
path_ptr->block.dirty = true;
goto finish;
}
}
append_extent:
/* Append new extent to the tree */
phys_block = 0;
rc = ext4_fs_indirect_find_goal(inode_ref, &goal);
if (rc != EOK)
goto finish;
/* Allocate new data block */
rc = ext4_balloc_alloc_block(inode_ref, goal, &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, false);
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;
}
ext4_extent_block_csum_set(inode_ref, path_ptr->header);
path_ptr->block.dirty = true;
finish:
/* Set return values */
*iblock = new_block_idx;
*fblock = phys_block;
/*
* Put loaded blocks
* starting from 1: 0 is a block with inode data
*/
for (i = 1; i <= path->depth; ++i) {
if (path[i].block.lb_id) {
int r =
ext4_block_set(inode_ref->fs->bdev, &path[i].block);
if (r != EOK)
rc = r;
}
}
/* Destroy temporary data structure */
free(path);
return rc;
}
int ext4_extent_get_blocks(struct ext4_inode_ref *inode_ref, ext4_fsblk_t iblock,
ext4_lblk_t max_blocks, ext4_fsblk_t *result, bool create,
ext4_lblk_t *blocks_count)
{
uint32_t iblk = iblock;
ext4_fsblk_t fblk = 0;
int r;
if (blocks_count)
return ENOTSUP;
if (max_blocks != 1)
return ENOTSUP;
if (!create)
r = ext4_extent_find_block(inode_ref, iblk, &fblk);
else
r = ext4_extent_append_block(inode_ref, &iblk, &fblk, false);
*result = fblk;
return r;
}
#endif
/**
* @}
*/