forked from Bananymous/banan-os
507 lines
16 KiB
C++
507 lines
16 KiB
C++
#include <BAN/ScopeGuard.h>
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#include <kernel/FS/Ext2/FileSystem.h>
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#include <kernel/Lock/LockGuard.h>
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#define EXT2_DEBUG_PRINT 0
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#define EXT2_VERIFY_INODE 0
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#define EXT2_VERIFY_NO_BLOCKS 1
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namespace Kernel
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{
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BAN::ErrorOr<Ext2FS*> Ext2FS::create(BAN::RefPtr<BlockDevice> block_device)
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{
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Ext2FS* ext2fs = new Ext2FS(block_device);
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if (ext2fs == nullptr)
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return BAN::Error::from_errno(ENOMEM);
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BAN::ScopeGuard guard([ext2fs] { delete ext2fs; });
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TRY(ext2fs->initialize_superblock());
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TRY(ext2fs->initialize_root_inode());
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guard.disable();
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return ext2fs;
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}
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BAN::ErrorOr<void> Ext2FS::initialize_superblock()
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{
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// Read superblock from disk
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{
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const uint32_t sector_size = m_block_device->blksize();
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ASSERT(1024 % sector_size == 0);
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const uint32_t lba = 1024 / sector_size;
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const uint32_t sector_count = BAN::Math::div_round_up<uint32_t>(sizeof(Ext2::Superblock), sector_size);
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BAN::Vector<uint8_t> superblock_buffer;
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TRY(superblock_buffer.resize(sector_count * sector_size));
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TRY(m_block_device->read_blocks(lba, sector_count, BAN::ByteSpan(superblock_buffer.span())));
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memcpy(&m_superblock, superblock_buffer.data(), sizeof(Ext2::Superblock));
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}
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if (m_superblock.magic != Ext2::Enum::SUPER_MAGIC)
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return BAN::Error::from_error_code(ErrorCode::Ext2_Invalid);
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if (m_superblock.rev_level == Ext2::Enum::GOOD_OLD_REV)
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{
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memset(m_superblock.__extension_start, 0, sizeof(Ext2::Superblock) - offsetof(Ext2::Superblock, Ext2::Superblock::__extension_start));
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m_superblock.first_ino = Ext2::Enum::GOOD_OLD_FIRST_INO;
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m_superblock.inode_size = Ext2::Enum::GOOD_OLD_INODE_SIZE;
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}
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const uint32_t number_of_block_groups = BAN::Math::div_round_up(superblock().inodes_count, superblock().inodes_per_group);
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const uint32_t number_of_block_groups_check = BAN::Math::div_round_up(superblock().blocks_count, superblock().blocks_per_group);
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if (number_of_block_groups != number_of_block_groups_check)
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return BAN::Error::from_error_code(ErrorCode::Ext2_Corrupted);
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if (!(m_superblock.feature_incompat & Ext2::Enum::FEATURE_INCOMPAT_FILETYPE))
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{
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dwarnln("Directory entries without filetype not supported");
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return BAN::Error::from_errno(ENOTSUP);
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}
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if (m_superblock.feature_incompat & Ext2::Enum::FEATURE_INCOMPAT_COMPRESSION)
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{
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dwarnln("Required FEATURE_INCOMPAT_COMPRESSION");
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return BAN::Error::from_errno(ENOTSUP);
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}
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if (m_superblock.feature_incompat & Ext2::Enum::FEATURE_INCOMPAT_JOURNAL_DEV)
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{
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dwarnln("Required FEATURE_INCOMPAT_JOURNAL_DEV");
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return BAN::Error::from_errno(ENOTSUP);
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}
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if (m_superblock.feature_incompat & Ext2::Enum::FEATURE_INCOMPAT_META_BG)
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{
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dwarnln("Required FEATURE_INCOMPAT_META_BG");
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return BAN::Error::from_errno(ENOTSUP);
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}
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if (m_superblock.feature_incompat & Ext2::Enum::FEATURE_INCOMPAT_RECOVER)
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{
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dwarnln("Required FEATURE_INCOMPAT_RECOVER");
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return BAN::Error::from_errno(ENOTSUP);
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}
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#if EXT2_DEBUG_PRINT
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dprintln("EXT2");
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dprintln(" inodes {}", m_superblock.inodes_count);
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dprintln(" blocks {}", m_superblock.blocks_count);
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dprintln(" version {}.{}", m_superblock.rev_level, m_superblock.minor_rev_level);
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dprintln(" first data at {}", m_superblock.first_data_block);
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dprintln(" block size {}", 1024 << m_superblock.log_block_size);
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dprintln(" inode size {}", m_superblock.inode_size);
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dprintln(" inodes/group {}", m_superblock.inodes_per_group);
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#endif
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TRY(m_buffer_manager.initialize(block_size()));
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{
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auto block_buffer = m_buffer_manager.get_buffer();
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if (superblock().rev_level == Ext2::Enum::GOOD_OLD_REV)
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{
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// In revision 0 all blockgroups contain superblock backup
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TRY(m_superblock_backups.reserve(number_of_block_groups - 1));
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for (uint32_t i = 1; i < number_of_block_groups; i++)
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MUST(m_superblock_backups.push_back(i));
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}
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else
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{
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// In other revision superblock backups are on blocks 1 and powers of 3, 5 and 7
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if (1 < number_of_block_groups)
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TRY(m_superblock_backups.push_back(1));
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for (uint32_t i = 3; i < number_of_block_groups; i *= 3)
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TRY(m_superblock_backups.push_back(i));
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for (uint32_t i = 5; i < number_of_block_groups; i *= 5)
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TRY(m_superblock_backups.push_back(i));
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for (uint32_t i = 7; i < number_of_block_groups; i *= 7)
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TRY(m_superblock_backups.push_back(i));
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// We don't really care if this succeeds or not
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(void)m_superblock_backups.shrink_to_fit();
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}
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for (uint32_t bg : m_superblock_backups)
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{
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read_block(superblock().first_data_block + superblock().blocks_per_group * bg, block_buffer);
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Ext2::Superblock& superblock_backup = *(Ext2::Superblock*)block_buffer.data();
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if (superblock_backup.magic != Ext2::Enum::SUPER_MAGIC)
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derrorln("superblock backup at block {} is invalid ({4H})", bg, superblock_backup.magic);
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}
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}
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return {};
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}
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BAN::ErrorOr<void> Ext2FS::initialize_root_inode()
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{
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m_root_inode = TRY(Ext2Inode::create(*this, Ext2::Enum::ROOT_INO));
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return {};
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}
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BAN::ErrorOr<uint32_t> Ext2FS::create_inode(const Ext2::Inode& ext2_inode)
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{
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LockGuard _(m_mutex);
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ASSERT(ext2_inode.size == 0);
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if (m_superblock.free_inodes_count == 0)
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return BAN::Error::from_errno(ENOSPC);
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const uint32_t block_size = this->block_size();
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auto bgd_buffer = m_buffer_manager.get_buffer();
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auto inode_bitmap = m_buffer_manager.get_buffer();
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uint32_t current_group = -1;
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BlockLocation bgd_location {};
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Ext2::BlockGroupDescriptor* bgd = nullptr;
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for (uint32_t ino = superblock().first_ino; ino <= superblock().inodes_count; ino++)
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{
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const uint32_t ino_group = (ino - 1) / superblock().inodes_per_group;
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const uint32_t ino_index = (ino - 1) % superblock().inodes_per_group;
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if (ino_group != current_group)
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{
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current_group = ino_group;
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bgd_location = locate_block_group_descriptior(current_group);
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read_block(bgd_location.block, bgd_buffer);
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bgd = (Ext2::BlockGroupDescriptor*)(bgd_buffer.data() + bgd_location.offset);
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if (bgd->free_inodes_count == 0)
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{
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ino = superblock().first_ino + (current_group + 1) * superblock().inodes_per_group - 1;
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continue;
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}
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read_block(bgd->inode_bitmap, inode_bitmap);
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}
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const uint32_t ino_bitmap_byte = ino_index / 8;
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const uint32_t ino_bitmap_bit = ino_index % 8;
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if (inode_bitmap[ino_bitmap_byte] & (1 << ino_bitmap_bit))
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continue;
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inode_bitmap[ino_bitmap_byte] |= 1 << ino_bitmap_bit;
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write_block(bgd->inode_bitmap, inode_bitmap);
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bgd->free_inodes_count--;
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if (Inode::Mode(ext2_inode.mode).ifdir())
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bgd->used_dirs_count++;
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write_block(bgd_location.block, bgd_buffer);
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const uint32_t inode_table_offset = ino_index * superblock().inode_size;
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const BlockLocation inode_location
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{
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.block = inode_table_offset / block_size + bgd->inode_table,
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.offset = inode_table_offset % block_size
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};
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// NOTE: we don't need inode bitmap anymore, so we can reuse it
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auto& inode_buffer = inode_bitmap;
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read_block(inode_location.block, inode_buffer);
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memcpy(inode_buffer.data() + inode_location.offset, &ext2_inode, sizeof(Ext2::Inode));
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if (superblock().inode_size > sizeof(Ext2::Inode))
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memset(inode_buffer.data() + inode_location.offset + sizeof(Ext2::Inode), 0, superblock().inode_size - sizeof(Ext2::Inode));
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write_block(inode_location.block, inode_buffer);
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m_superblock.free_inodes_count--;
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sync_superblock();
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return ino;
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}
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derrorln("Corrupted file system. Superblock indicates free inodes but none were found.");
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return BAN::Error::from_error_code(ErrorCode::Ext2_Corrupted);
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}
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void Ext2FS::delete_inode(uint32_t ino)
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{
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LockGuard _(m_mutex);
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ASSERT(ino >= superblock().first_ino);
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ASSERT(ino <= superblock().inodes_count);
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auto bgd_buffer = get_block_buffer();
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auto bitmap_buffer = get_block_buffer();
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auto inode_buffer = get_block_buffer();
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const uint32_t inode_group = (ino - 1) / superblock().inodes_per_group;
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const uint32_t inode_index = (ino - 1) % superblock().inodes_per_group;
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auto bgd_location = locate_block_group_descriptior(inode_group);
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read_block(bgd_location.block, bgd_buffer);
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auto& bgd = bgd_buffer.span().slice(bgd_location.offset).as<Ext2::BlockGroupDescriptor>();
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// update inode bitmap
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read_block(bgd.inode_bitmap, bitmap_buffer);
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const uint32_t byte = inode_index / 8;
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const uint32_t bit = inode_index % 8;
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ASSERT(bitmap_buffer[byte] & (1 << bit));
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bitmap_buffer[byte] &= ~(1 << bit);
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write_block(bgd.inode_bitmap, bitmap_buffer);
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// memset inode to zero or fsck will complain
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auto inode_location = locate_inode(ino);
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read_block(inode_location.block, inode_buffer);
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auto& inode = inode_buffer.span().slice(inode_location.offset).as<Ext2::Inode>();
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#if EXT2_VERIFY_NO_BLOCKS
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static const char zero_buffer[sizeof(inode.block)] {};
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ASSERT(memcmp(inode.block, zero_buffer, sizeof(inode.block)) == 0);
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#endif
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bool is_directory = Inode::Mode(inode.mode).ifdir();
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memset(&inode, 0x00, m_superblock.inode_size);
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write_block(inode_location.block, inode_buffer);
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// update bgd counts
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bgd.free_inodes_count++;
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if (is_directory)
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bgd.used_dirs_count--;
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write_block(bgd_location.block, bgd_buffer);
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// update superblock inode count
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m_superblock.free_inodes_count++;
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sync_superblock();
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// remove inode from cache
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if (m_inode_cache.contains(ino))
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m_inode_cache.remove(ino);
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}
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void Ext2FS::read_block(uint32_t block, BlockBufferWrapper& buffer)
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{
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LockGuard _(m_mutex);
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const uint32_t sector_size = m_block_device->blksize();
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const uint32_t block_size = this->block_size();
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const uint32_t sectors_per_block = block_size / sector_size;
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ASSERT(block >= superblock().first_data_block + 1);
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ASSERT(buffer.size() >= block_size);
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MUST(m_block_device->read_blocks(block * sectors_per_block, sectors_per_block, buffer.span()));
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}
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void Ext2FS::write_block(uint32_t block, const BlockBufferWrapper& buffer)
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{
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LockGuard _(m_mutex);
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const uint32_t sector_size = m_block_device->blksize();
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const uint32_t block_size = this->block_size();
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const uint32_t sectors_per_block = block_size / sector_size;
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ASSERT(block >= superblock().first_data_block + 1);
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ASSERT(buffer.size() >= block_size);
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MUST(m_block_device->write_blocks(block * sectors_per_block, sectors_per_block, buffer.span()));
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}
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void Ext2FS::sync_superblock()
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{
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LockGuard _(m_mutex);
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const uint32_t sector_size = m_block_device->blksize();
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ASSERT(1024 % sector_size == 0);
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const uint32_t superblock_bytes =
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(m_superblock.rev_level == Ext2::Enum::GOOD_OLD_REV)
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? offsetof(Ext2::Superblock, __extension_start)
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: sizeof(Ext2::Superblock);
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const uint32_t lba = 1024 / sector_size;
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const uint32_t sector_count = BAN::Math::div_round_up<uint32_t>(superblock_bytes, sector_size);
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auto superblock_buffer = get_block_buffer();
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MUST(m_block_device->read_blocks(lba, sector_count, superblock_buffer.span()));
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if (memcmp(superblock_buffer.data(), &m_superblock, superblock_bytes))
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{
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memcpy(superblock_buffer.data(), &m_superblock, superblock_bytes);
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MUST(m_block_device->write_blocks(lba, sector_count, superblock_buffer.span()));
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}
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}
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Ext2FS::BlockBufferWrapper Ext2FS::get_block_buffer()
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{
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LockGuard _(m_mutex);
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return m_buffer_manager.get_buffer();
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}
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BAN::ErrorOr<uint32_t> Ext2FS::reserve_free_block(uint32_t primary_bgd)
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{
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LockGuard _(m_mutex);
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if (m_superblock.r_blocks_count >= m_superblock.free_blocks_count)
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return BAN::Error::from_errno(ENOSPC);
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auto bgd_buffer = m_buffer_manager.get_buffer();
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auto block_bitmap = m_buffer_manager.get_buffer();
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auto check_block_group =
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[&](uint32_t block_group) -> uint32_t
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{
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auto bgd_location = locate_block_group_descriptior(block_group);
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read_block(bgd_location.block, bgd_buffer);
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auto& bgd = *(Ext2::BlockGroupDescriptor*)(bgd_buffer.data() + bgd_location.offset);
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if (bgd.free_blocks_count == 0)
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return 0;
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read_block(bgd.block_bitmap, block_bitmap);
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for (uint32_t block_offset = 0; block_offset < m_superblock.blocks_per_group; block_offset++)
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{
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const uint32_t fs_block_index = m_superblock.first_data_block + m_superblock.blocks_per_group * block_group + block_offset;
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if (fs_block_index >= m_superblock.blocks_count)
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break;
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uint32_t byte = block_offset / 8;
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uint32_t bit = block_offset % 8;
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if (block_bitmap[byte] & (1 << bit))
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continue;
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block_bitmap[byte] |= 1 << bit;
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write_block(bgd.block_bitmap, block_bitmap);
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bgd.free_blocks_count--;
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write_block(bgd_location.block, bgd_buffer);
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m_superblock.free_blocks_count--;
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sync_superblock();
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return fs_block_index;
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}
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derrorln("Corrupted file system. Block group descriptor indicates free blocks but none were found");
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return 0;
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};
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if (auto ret = check_block_group(primary_bgd))
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return ret;
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uint32_t number_of_block_groups = BAN::Math::div_round_up(m_superblock.blocks_count, m_superblock.blocks_per_group);
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for (uint32_t block_group = 0; block_group < number_of_block_groups; block_group++)
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if (block_group != primary_bgd)
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if (auto ret = check_block_group(block_group))
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return ret;
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derrorln("Corrupted file system. Superblock indicates free blocks but none were found.");
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return BAN::Error::from_error_code(ErrorCode::Ext2_Corrupted);
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}
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void Ext2FS::release_block(uint32_t block)
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{
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LockGuard _(m_mutex);
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ASSERT(block >= m_superblock.first_data_block);
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ASSERT(block < m_superblock.blocks_count);
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const uint32_t block_group = (block - m_superblock.first_data_block) / m_superblock.blocks_per_group;
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const uint32_t block_offset = (block - m_superblock.first_data_block) % m_superblock.blocks_per_group;
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auto bgd_buffer = get_block_buffer();
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auto bitmap_buffer = get_block_buffer();
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auto bgd_location = locate_block_group_descriptior(block_group);
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read_block(bgd_location.block, bgd_buffer);
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auto& bgd = bgd_buffer.span().slice(bgd_location.offset).as<Ext2::BlockGroupDescriptor>();
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read_block(bgd.block_bitmap, bitmap_buffer);
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const uint32_t byte = block_offset / 8;
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const uint32_t bit = block_offset % 8;
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ASSERT(bitmap_buffer[byte] & (1 << bit));
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bitmap_buffer[byte] &= ~(1 << bit);
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write_block(bgd.block_bitmap, bitmap_buffer);
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bgd.free_blocks_count++;
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write_block(bgd_location.block, bgd_buffer);
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m_superblock.free_blocks_count++;
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sync_superblock();
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}
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Ext2FS::BlockLocation Ext2FS::locate_inode(uint32_t ino)
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{
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LockGuard _(m_mutex);
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ASSERT(ino <= superblock().inodes_count);
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const uint32_t block_size = this->block_size();
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auto bgd_buffer = m_buffer_manager.get_buffer();
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const uint32_t inode_group = (ino - 1) / superblock().inodes_per_group;
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const uint32_t inode_index = (ino - 1) % superblock().inodes_per_group;
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auto bgd_location = locate_block_group_descriptior(inode_group);
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read_block(bgd_location.block, bgd_buffer);
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auto& bgd = *(Ext2::BlockGroupDescriptor*)(bgd_buffer.data() + bgd_location.offset);
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const uint32_t inode_byte_offset = inode_index * superblock().inode_size;
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BlockLocation location
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{
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.block = inode_byte_offset / block_size + bgd.inode_table,
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.offset = inode_byte_offset % block_size
|
|
};
|
|
|
|
#if EXT2_VERIFY_INODE
|
|
const uint32_t inode_bitmap_block = bgd.inode_bitmap;
|
|
|
|
// NOTE: we can reuse the bgd_buffer since it is not needed anymore
|
|
auto& inode_bitmap = bgd_buffer;
|
|
|
|
read_block(inode_bitmap_block, inode_bitmap.span());
|
|
|
|
const uint32_t byte = inode_index / 8;
|
|
const uint32_t bit = inode_index % 8;
|
|
ASSERT(inode_bitmap[byte] & (1 << bit));
|
|
#endif
|
|
|
|
return location;
|
|
}
|
|
|
|
Ext2FS::BlockLocation Ext2FS::locate_block_group_descriptior(uint32_t group_index)
|
|
{
|
|
LockGuard _(m_mutex);
|
|
|
|
const uint32_t block_size = this->block_size();
|
|
|
|
const uint32_t block_group_count = BAN::Math::div_round_up(superblock().inodes_count, superblock().inodes_per_group);
|
|
ASSERT(group_index < block_group_count);
|
|
|
|
// Block Group Descriptor table is in the block after superblock
|
|
const uint32_t bgd_byte_offset = (superblock().first_data_block + 1) * block_size + sizeof(Ext2::BlockGroupDescriptor) * group_index;
|
|
|
|
return
|
|
{
|
|
.block = bgd_byte_offset / block_size,
|
|
.offset = bgd_byte_offset % block_size
|
|
};
|
|
}
|
|
|
|
Ext2FS::BlockBufferWrapper Ext2FS::BlockBufferManager::get_buffer()
|
|
{
|
|
for (auto& buffer : m_buffers)
|
|
{
|
|
if (buffer.used)
|
|
continue;
|
|
buffer.used = true;
|
|
return Ext2FS::BlockBufferWrapper(buffer.buffer.span(), buffer.used);
|
|
}
|
|
ASSERT_NOT_REACHED();
|
|
}
|
|
|
|
BAN::ErrorOr<void> Ext2FS::BlockBufferManager::initialize(size_t block_size)
|
|
{
|
|
for (auto& buffer : m_buffers)
|
|
{
|
|
TRY(buffer.buffer.resize(block_size));
|
|
buffer.used = false;
|
|
}
|
|
return {};
|
|
}
|
|
|
|
}
|