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Kernel/Ext2: Extract common calculations to functions

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This also makes it easier to understand and reference where these
(sometimes rather arbitrary) calculations come from.

This also fixes a bug where group_index_from_block_index assumed 1KiB
blocks.
This commit is contained in:
kleines Filmröllchen 2023-07-18 15:09:48 +02:00 • committed by Jelle Raaijmakers
parent 6a17a30e2e
commit cc1cb72fb5
2 changed files with 16 additions and 4 deletions
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18
Kernel/FileSystem/Ext2FS/FileSystem.cpp
View file

@ -95,7 +95,7 @@ ErrorOr<void> Ext2FS::initialize_while_locked()
} }
auto blocks_to_read = ceil_div(m_block_group_count * sizeof(ext2_group_desc), block_size()); auto blocks_to_read = ceil_div(m_block_group_count * sizeof(ext2_group_desc), block_size());
BlockIndex first_block_of_bgdt = block_size() == 1024 ? 2 : 1; BlockIndex first_block_of_bgdt = first_block_of_block_group_descriptors();
m_cached_group_descriptor_table = TRY(KBuffer::try_create_with_size("Ext2FS: Block group descriptors"sv, block_size() * blocks_to_read, Memory::Region::Access::ReadWrite)); m_cached_group_descriptor_table = TRY(KBuffer::try_create_with_size("Ext2FS: Block group descriptors"sv, block_size() * blocks_to_read, Memory::Region::Access::ReadWrite));
auto buffer = UserOrKernelBuffer::for_kernel_buffer(m_cached_group_descriptor_table->data()); auto buffer = UserOrKernelBuffer::for_kernel_buffer(m_cached_group_descriptor_table->data());
TRY(read_blocks(first_block_of_bgdt, blocks_to_read, buffer)); TRY(read_blocks(first_block_of_bgdt, blocks_to_read, buffer));
@ -271,7 +271,7 @@ auto Ext2FS::allocate_blocks(GroupIndex preferred_group_index, size_t count) ->
int blocks_in_group = min(blocks_per_group(), super_block().s_blocks_count); int blocks_in_group = min(blocks_per_group(), super_block().s_blocks_count);
auto block_bitmap = cached_bitmap->bitmap(blocks_in_group); auto block_bitmap = cached_bitmap->bitmap(blocks_in_group);
BlockIndex first_block_in_group = (group_index.value() - 1) * blocks_per_group() + first_block_index().value(); BlockIndex first_block_in_group = first_block_of_group(group_index);
size_t free_region_size = 0; size_t free_region_size = 0;
auto first_unset_bit_index = block_bitmap.find_longest_range_of_unset_bits(count - blocks.size(), free_region_size); auto first_unset_bit_index = block_bitmap.find_longest_range_of_unset_bits(count - blocks.size(), free_region_size);
VERIFY(first_unset_bit_index.has_value()); VERIFY(first_unset_bit_index.has_value());
@ -352,7 +352,17 @@ Ext2FS::GroupIndex Ext2FS::group_index_from_block_index(BlockIndex block_index)
{ {
if (!block_index) if (!block_index)
return 0; return 0;
return (block_index.value() - 1) / blocks_per_group() + 1; return (block_index.value() - first_block_index().value()) / blocks_per_group() + 1;
}
Ext2FS::BlockIndex Ext2FS::first_block_of_group(GroupIndex group_index) const
{
return (group_index.value() - 1) * blocks_per_group() + first_block_index().value();
}
Ext2FS::BlockIndex Ext2FS::first_block_of_block_group_descriptors() const
{
return block_size() == 1024 ? 2 : 1;
} }
auto Ext2FS::group_index_from_inode(InodeIndex inode) const -> GroupIndex auto Ext2FS::group_index_from_inode(InodeIndex inode) const -> GroupIndex
@ -612,7 +622,7 @@ void Ext2FS::flush_block_group_descriptor_table()
{ {
MutexLocker locker(m_lock); MutexLocker locker(m_lock);
auto blocks_to_write = ceil_div(m_block_group_count * sizeof(ext2_group_desc), block_size()); auto blocks_to_write = ceil_div(m_block_group_count * sizeof(ext2_group_desc), block_size());
auto first_block_of_bgdt = block_size() == 1024 ? 2 : 1; auto first_block_of_bgdt = first_block_of_block_group_descriptors();
auto buffer = UserOrKernelBuffer::for_kernel_buffer((u8*)block_group_descriptors()); auto buffer = UserOrKernelBuffer::for_kernel_buffer((u8*)block_group_descriptors());
if (auto result = write_blocks(first_block_of_bgdt, blocks_to_write, buffer); result.is_error()) if (auto result = write_blocks(first_block_of_bgdt, blocks_to_write, buffer); result.is_error())
dbgln("Ext2FS[{}]::flush_block_group_descriptor_table(): Failed to write blocks: {}", fsid(), result.error()); dbgln("Ext2FS[{}]::flush_block_group_descriptor_table(): Failed to write blocks: {}", fsid(), result.error());

2
Kernel/FileSystem/Ext2FS/FileSystem.h
View file

@ -77,10 +77,12 @@ private:
virtual void flush_writes() override; virtual void flush_writes() override;
BlockIndex first_block_index() const; BlockIndex first_block_index() const;
BlockIndex first_block_of_block_group_descriptors() const;
ErrorOr<InodeIndex> allocate_inode(GroupIndex preferred_group = 0); ErrorOr<InodeIndex> allocate_inode(GroupIndex preferred_group = 0);
ErrorOr<Vector<BlockIndex>> allocate_blocks(GroupIndex preferred_group_index, size_t count); ErrorOr<Vector<BlockIndex>> allocate_blocks(GroupIndex preferred_group_index, size_t count);
GroupIndex group_index_from_inode(InodeIndex) const; GroupIndex group_index_from_inode(InodeIndex) const;
GroupIndex group_index_from_block_index(BlockIndex) const; GroupIndex group_index_from_block_index(BlockIndex) const;
BlockIndex first_block_of_group(GroupIndex) const;
ErrorOr<bool> get_inode_allocation_state(InodeIndex) const; ErrorOr<bool> get_inode_allocation_state(InodeIndex) const;
ErrorOr<void> set_inode_allocation_state(InodeIndex, bool); ErrorOr<void> set_inode_allocation_state(InodeIndex, bool);