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https://github.com/RGBCube/serenity
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Kernel: Convert read_block method to get a reference instead of pointer
BlockBasedFileSystem::read_block method should get a reference of a UserOrKernelBuffer. If we need to force caching a block, we will call other method to do so.
This commit is contained in:
Liav A
Andreas Kling
parent
d1366b660e
commit
092a13211a
3 changed files with 80 additions and 47 deletions
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@ -32,19 +32,12 @@
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namespace Kernel {
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struct CacheEntry {
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IntrusiveListNode list_node;
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u32 block_index { 0 };
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u8* data { nullptr };
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bool has_data { false };
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};
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class DiskCache {
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public:
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explicit DiskCache(BlockBasedFS& fs)
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: m_fs(fs)
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, m_cached_block_data(KBuffer::create_with_size(m_entry_count * m_fs.block_size()))
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, m_entries(KBuffer::create_with_size(m_entry_count * sizeof(CacheEntry)))
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, m_entries(KBuffer::create_with_size(m_entry_count * sizeof(BlockBasedFS::CacheEntry&)))
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{
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for (size_t i = 0; i < m_entry_count; ++i) {
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entries()[i].data = m_cached_block_data.data() + i * m_fs.block_size();
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@ -64,21 +57,21 @@ public:
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m_dirty = false;
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}
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void mark_dirty(CacheEntry& entry)
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void mark_dirty(BlockBasedFS::CacheEntry& entry)
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{
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m_dirty_list.prepend(entry);
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m_dirty = true;
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}
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void mark_clean(CacheEntry& entry)
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void mark_clean(BlockBasedFS::CacheEntry& entry)
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{
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m_clean_list.prepend(entry);
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}
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CacheEntry& get(u32 block_index) const
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BlockBasedFS::CacheEntry& get(u32 block_index) const
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{
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if (auto it = m_hash.find(block_index); it != m_hash.end()) {
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auto& entry = const_cast<CacheEntry&>(*it->value);
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auto& entry = const_cast<BlockBasedFS::CacheEntry&>(*it->value);
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ASSERT(entry.block_index == block_index);
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return entry;
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}
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@ -104,8 +97,8 @@ public:
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return new_entry;
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}
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const CacheEntry* entries() const { return (const CacheEntry*)m_entries.data(); }
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CacheEntry* entries() { return (CacheEntry*)m_entries.data(); }
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const BlockBasedFS::CacheEntry* entries() const { return (const BlockBasedFS::CacheEntry*)m_entries.data(); }
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BlockBasedFS::CacheEntry* entries() { return (BlockBasedFS::CacheEntry*)m_entries.data(); }
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template<typename Callback>
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void for_each_clean_entry(Callback callback)
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@ -124,9 +117,9 @@ public:
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private:
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BlockBasedFS& m_fs;
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size_t m_entry_count { 10000 };
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mutable HashMap<u32, CacheEntry*> m_hash;
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mutable IntrusiveList<CacheEntry, &CacheEntry::list_node> m_clean_list;
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mutable IntrusiveList<CacheEntry, &CacheEntry::list_node> m_dirty_list;
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mutable HashMap<u32, BlockBasedFS::CacheEntry*> m_hash;
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mutable IntrusiveList<BlockBasedFS::CacheEntry, &BlockBasedFS::CacheEntry::list_node> m_clean_list;
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mutable IntrusiveList<BlockBasedFS::CacheEntry, &BlockBasedFS::CacheEntry::list_node> m_dirty_list;
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KBuffer m_cached_block_data;
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KBuffer m_entries;
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bool m_dirty { false };
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@ -161,19 +154,50 @@ int BlockBasedFS::write_block(unsigned index, const UserOrKernelBuffer& data, si
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return 0;
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}
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auto& entry = cache().get(index);
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auto entry_or_error = cache_block(index);
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if (entry_or_error.is_error())
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return -EIO;
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if (!entry_or_error.value().has_data)
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return -EIO;
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if (count < block_size()) {
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// Fill the cache first.
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read_block(index, nullptr, block_size());
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if (!force_cache_block(index))
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return -EIO;
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}
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if (!data.read(entry.data + offset, count))
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if (!data.read(entry_or_error.value().data + offset, count))
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return -EFAULT;
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cache().mark_dirty(entry);
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entry.has_data = true;
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cache().mark_dirty(entry_or_error.value());
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// Update the actual entry and not the copy of it!
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cache().get(index).has_data = true;
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return 0;
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}
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bool BlockBasedFS::force_cache_block(unsigned index) const
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{
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auto& entry = cache().get(index);
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u32 base_offset = static_cast<u32>(index) * static_cast<u32>(block_size());
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file_description().seek(base_offset, SEEK_SET);
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auto entry_data_buffer = UserOrKernelBuffer::for_kernel_buffer(entry.data);
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auto nread = file_description().read(entry_data_buffer, block_size());
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if (nread.is_error())
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return false;
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ASSERT(nread.value() == block_size());
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entry.has_data = true;
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return true;
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}
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KResultOr<BlockBasedFS::CacheEntry> BlockBasedFS::cache_block(unsigned index) const
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{
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auto& entry = cache().get(index);
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if (!entry.has_data) {
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if (!force_cache_block(index))
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return KResult(-EIO);
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}
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return entry;
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}
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bool BlockBasedFS::raw_read(unsigned index, UserOrKernelBuffer& buffer)
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{
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u32 base_offset = static_cast<u32>(index) * static_cast<u32>(m_logical_block_size);
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@ -225,7 +249,7 @@ int BlockBasedFS::write_blocks(unsigned index, unsigned count, const UserOrKerne
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return 0;
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}
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int BlockBasedFS::read_block(unsigned index, UserOrKernelBuffer* buffer, size_t count, size_t offset, bool allow_cache) const
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int BlockBasedFS::read_block(unsigned index, UserOrKernelBuffer& buffer, size_t count, size_t offset, bool allow_cache) const
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{
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ASSERT(m_logical_block_size);
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ASSERT(offset + count <= block_size());
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@ -237,25 +261,19 @@ int BlockBasedFS::read_block(unsigned index, UserOrKernelBuffer* buffer, size_t
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const_cast<BlockBasedFS*>(this)->flush_specific_block_if_needed(index);
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u32 base_offset = static_cast<u32>(index) * static_cast<u32>(block_size()) + static_cast<u32>(offset);
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file_description().seek(base_offset, SEEK_SET);
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auto nread = file_description().read(*buffer, count);
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auto nread = file_description().read(buffer, count);
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if (nread.is_error())
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return -EIO;
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ASSERT(nread.value() == count);
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return 0;
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}
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auto& entry = cache().get(index);
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if (!entry.has_data) {
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u32 base_offset = static_cast<u32>(index) * static_cast<u32>(block_size());
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file_description().seek(base_offset, SEEK_SET);
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auto entry_data_buffer = UserOrKernelBuffer::for_kernel_buffer(entry.data);
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auto nread = file_description().read(entry_data_buffer, block_size());
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if (nread.is_error())
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return -EIO;
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ASSERT(nread.value() == block_size());
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entry.has_data = true;
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}
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if (buffer && !buffer->write(entry.data + offset, count))
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auto entry_or_error = cache_block(index);
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if (entry_or_error.is_error())
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return -EIO;
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if (!entry_or_error.value().has_data)
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return -EIO;
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if (!buffer.write(entry_or_error.value().data + offset, count))
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return -EFAULT;
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return 0;
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}
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@ -266,10 +284,10 @@ int BlockBasedFS::read_blocks(unsigned index, unsigned count, UserOrKernelBuffer
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if (!count)
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return false;
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if (count == 1)
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return read_block(index, &buffer, block_size(), 0, allow_cache);
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return read_block(index, buffer, block_size(), 0, allow_cache);
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auto out = buffer;
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for (unsigned i = 0; i < count; ++i) {
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auto err = read_block(index + i, &out, block_size(), 0, allow_cache);
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auto err = read_block(index + i, out, block_size(), 0, allow_cache);
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if (err < 0)
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return err;
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out = out.offset(block_size());
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@ -284,7 +302,7 @@ void BlockBasedFS::flush_specific_block_if_needed(unsigned index)
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if (!cache().is_dirty())
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return;
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Vector<CacheEntry*, 32> cleaned_entries;
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cache().for_each_dirty_entry([&](CacheEntry& entry) {
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cache().for_each_dirty_entry([&](BlockBasedFS::CacheEntry& entry) {
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if (entry.block_index != index) {
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u32 base_offset = static_cast<u32>(entry.block_index) * static_cast<u32>(block_size());
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file_description().seek(base_offset, SEEK_SET);
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@ -306,7 +324,7 @@ void BlockBasedFS::flush_writes_impl()
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if (!cache().is_dirty())
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return;
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u32 count = 0;
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cache().for_each_dirty_entry([&](CacheEntry& entry) {
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cache().for_each_dirty_entry([&](BlockBasedFS::CacheEntry& entry) {
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u32 base_offset = static_cast<u32>(entry.block_index) * static_cast<u32>(block_size());
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file_description().seek(base_offset, SEEK_SET);
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// FIXME: Should this error path be surfaced somehow?
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