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TmpFS: Use fallible KBuffer API

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If allocation fails, some TmpFS operations can now fail with ENOMEM.
This commit is contained in:
Andreas Kling 2020-12-18 13:34:57 +01:00
parent 47da86d136
commit bcd2844439
2 changed files with 25 additions and 19 deletions
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42
Kernel/FileSystem/TmpFS.cpp
View file

@ -153,7 +153,7 @@ ssize_t TmpFSInode::read_bytes(off_t offset, ssize_t size, UserOrKernelBuffer& b
ASSERT(size >= 0); ASSERT(size >= 0);
ASSERT(offset >= 0); ASSERT(offset >= 0);
if (!m_content.has_value()) if (!m_content)
return 0; return 0;
if (offset >= m_metadata.size) if (offset >= m_metadata.size)
@ -162,7 +162,7 @@ ssize_t TmpFSInode::read_bytes(off_t offset, ssize_t size, UserOrKernelBuffer& b
if (static_cast<off_t>(size) > m_metadata.size - offset) if (static_cast<off_t>(size) > m_metadata.size - offset)
size = m_metadata.size - offset; size = m_metadata.size - offset;
if (!buffer.write(m_content.value().data() + offset, size)) if (!buffer.write(m_content->data() + offset, size))
return -EFAULT; return -EFAULT;
return size; return size;
} }
@ -183,8 +183,8 @@ ssize_t TmpFSInode::write_bytes(off_t offset, ssize_t size, const UserOrKernelBu
new_size = offset + size; new_size = offset + size;
if (new_size > old_size) { if (new_size > old_size) {
if (m_content.has_value() && m_content.value().capacity() >= (size_t)new_size) { if (m_content && m_content->capacity() >= (size_t)new_size) {
m_content.value().set_size(new_size); m_content->set_size(new_size);
} else { } else {
// Grow the content buffer 2x the new sizeto accommodate repeating write() calls. // Grow the content buffer 2x the new sizeto accommodate repeating write() calls.
// Note that we're not actually committing physical memory to the buffer // Note that we're not actually committing physical memory to the buffer
@ -193,10 +193,12 @@ ssize_t TmpFSInode::write_bytes(off_t offset, ssize_t size, const UserOrKernelBu
// FIXME: Fix this so that no memcpy() is necessary, and we can just grow the // FIXME: Fix this so that no memcpy() is necessary, and we can just grow the
// KBuffer and it will add physical pages as needed while keeping the // KBuffer and it will add physical pages as needed while keeping the
// existing ones. // existing ones.
auto tmp = KBuffer::create_with_size(new_size * 2); auto tmp = KBuffer::try_create_with_size(new_size * 2);
tmp.set_size(new_size); if (!tmp)
if (m_content.has_value()) return -ENOMEM;
memcpy(tmp.data(), m_content.value().data(), old_size); tmp->set_size(new_size);
if (m_content)
memcpy(tmp->data(), m_content->data(), old_size);
m_content = move(tmp); m_content = move(tmp);
} }
m_metadata.size = new_size; m_metadata.size = new_size;
@ -205,7 +207,7 @@ ssize_t TmpFSInode::write_bytes(off_t offset, ssize_t size, const UserOrKernelBu
inode_size_changed(old_size, new_size); inode_size_changed(old_size, new_size);
} }
if (!buffer.read(m_content.value().data() + offset, size)) // TODO: partial reads? if (!buffer.read(m_content->data() + offset, size)) // TODO: partial reads?
return -EFAULT; return -EFAULT;
inode_contents_changed(offset, size, buffer); inode_contents_changed(offset, size, buffer);
@ -334,17 +336,21 @@ KResult TmpFSInode::truncate(u64 size)
if (size == 0) if (size == 0)
m_content.clear(); m_content.clear();
else if (!m_content.has_value()) { else if (!m_content) {
m_content = KBuffer::create_with_size(size); m_content = KBuffer::try_create_with_size(size);
} else if (static_cast<size_t>(size) < m_content.value().capacity()) { if (!m_content)
return KResult(-ENOMEM);
} else if (static_cast<size_t>(size) < m_content->capacity()) {
size_t prev_size = m_metadata.size; size_t prev_size = m_metadata.size;
m_content.value().set_size(size); m_content->set_size(size);
if (prev_size < static_cast<size_t>(size)) if (prev_size < static_cast<size_t>(size))
memset(m_content.value().data() + prev_size, 0, size - prev_size); memset(m_content->data() + prev_size, 0, size - prev_size);
} else { } else {
size_t prev_size = m_metadata.size; size_t prev_size = m_metadata.size;
KBuffer tmp = KBuffer::create_with_size(size); auto tmp = KBuffer::try_create_with_size(size);
memcpy(tmp.data(), m_content.value().data(), prev_size); if (!tmp)
return KResult(-ENOMEM);
memcpy(tmp->data(), m_content->data(), prev_size);
m_content = move(tmp); m_content = move(tmp);
} }
@ -354,8 +360,8 @@ KResult TmpFSInode::truncate(u64 size)
if (old_size != (size_t)size) { if (old_size != (size_t)size) {
inode_size_changed(old_size, size); inode_size_changed(old_size, size);
if (m_content.has_value()) { if (m_content) {
auto buffer = UserOrKernelBuffer::for_kernel_buffer(m_content.value().data()); auto buffer = UserOrKernelBuffer::for_kernel_buffer(m_content->data());
inode_contents_changed(0, size, buffer); inode_contents_changed(0, size, buffer);
} }
} }

2
Kernel/FileSystem/TmpFS.h
View file

@ -102,7 +102,7 @@ private:
InodeMetadata m_metadata; InodeMetadata m_metadata;
InodeIdentifier m_parent; InodeIdentifier m_parent;
Optional<KBuffer> m_content; OwnPtr<KBuffer> m_content;
struct Child { struct Child {
String name; String name;
NonnullRefPtr<TmpFSInode> inode; NonnullRefPtr<TmpFSInode> inode;