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Kernel: Made DiskCache entries a KBuffer

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The Cache entries found in `DiskBackedFileSystem` are now stored in a
`KBuffer` object, instead of relying on `kmalloc_eternal`. The number
of entries was exceeding that of the number of bytes allocated to
`kmalloc_eternal`, which in turn caused `mount()` to fail epically
when called.
This commit is contained in:
Jesse Buhagiar 2019-10-08 19:42:52 +11:00 • committed by Andreas Kling
parent 1ce8a175e1
commit 06b6af61c6
1 changed files with 10 additions and 6 deletions
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16
Kernel/FileSystem/DiskBackedFileSystem.cpp
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@ -18,10 +18,10 @@ public:
explicit DiskCache(DiskBackedFS& fs) explicit DiskCache(DiskBackedFS& fs)
: m_fs(fs) : m_fs(fs)
, m_cached_block_data(KBuffer::create_with_size(m_entry_count * m_fs.block_size())) , m_cached_block_data(KBuffer::create_with_size(m_entry_count * m_fs.block_size()))
, m_entries(KBuffer::create_with_size(m_entry_count * sizeof(CacheEntry)))
{ {
m_entries = (CacheEntry*)kmalloc_eternal(m_entry_count * sizeof(CacheEntry));
for (size_t i = 0; i < m_entry_count; ++i) { for (size_t i = 0; i < m_entry_count; ++i) {
m_entries[i].data = m_cached_block_data.data() + i * m_fs.block_size(); entries()[i].data = m_cached_block_data.data() + i * m_fs.block_size();
} }
} }
@ -36,7 +36,7 @@ public:
CacheEntry* oldest_clean_entry = nullptr; CacheEntry* oldest_clean_entry = nullptr;
for (size_t i = 0; i < m_entry_count; ++i) { for (size_t i = 0; i < m_entry_count; ++i) {
auto& entry = m_entries[i]; auto& entry = const_cast<CacheEntry&>(entries()[i]);
if (entry.block_index == block_index) { if (entry.block_index == block_index) {
entry.timestamp = now; entry.timestamp = now;
return entry; return entry;
@ -63,18 +63,21 @@ public:
return new_entry; return new_entry;
} }
const CacheEntry* entries() const { return (const CacheEntry*)m_entries.data(); }
CacheEntry* entries() { return (CacheEntry*)m_entries.data(); }
template<typename Callback> template<typename Callback>
void for_each_entry(Callback callback) void for_each_entry(Callback callback)
{ {
for (size_t i = 0; i < m_entry_count; ++i) for (size_t i = 0; i < m_entry_count; ++i)
callback(m_entries[i]); callback(entries()[i]);
} }
private: private:
DiskBackedFS& m_fs; DiskBackedFS& m_fs;
size_t m_entry_count { 10000 }; size_t m_entry_count { 10000 };
KBuffer m_cached_block_data; KBuffer m_cached_block_data;
CacheEntry* m_entries { nullptr }; KBuffer m_entries;
bool m_dirty { false }; bool m_dirty { false };
}; };
@ -160,7 +163,8 @@ void DiskBackedFS::flush_writes()
entry.is_dirty = false; entry.is_dirty = false;
}); });
cache().set_dirty(false); cache().set_dirty(false);
dbg() << class_name() << ": " << "Flushed " << count << " blocks to disk"; dbg() << class_name() << ": "
<< "Flushed " << count << " blocks to disk";
} }
DiskCache& DiskBackedFS::cache() const DiskCache& DiskBackedFS::cache() const