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Kernel: Make Inode::read_entire() return a KBuffer (not ByteBuffer)

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ByteBuffer is backed by kmalloc heap memory which is a scarce resource.
This fixes an OOM panic when traversing a large directory.
This commit is contained in:
Andreas Kling 2020-08-11 19:47:24 +02:00
parent ec93d6ffdc
commit 62ec6e5fe0
7 changed files with 12 additions and 16 deletions
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2
Kernel/FileSystem/FileDescription.cpp
View file

@ -163,7 +163,7 @@ bool FileDescription::can_read() const
return m_file->can_read(*this, offset());
}
KResultOr<ByteBuffer> FileDescription::read_entire_file()
KResultOr<KBuffer> FileDescription::read_entire_file()
{
// HACK ALERT: (This entire function)
ASSERT(m_file->is_inode());

2
Kernel/FileSystem/FileDescription.h
View file

@ -71,7 +71,7 @@ public:
ssize_t get_dir_entries(u8* buffer, ssize_t);
KResultOr<ByteBuffer> read_entire_file();
KResultOr<KBuffer> read_entire_file();
String absolute_path() const;

16
Kernel/FileSystem/Inode.cpp
View file

@ -31,6 +31,7 @@
#include <Kernel/FileSystem/Inode.h>
#include <Kernel/FileSystem/InodeWatcher.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/KBufferBuilder.h>
#include <Kernel/Net/LocalSocket.h>
#include <Kernel/VM/SharedInodeVMObject.h>
@ -65,10 +66,9 @@ void Inode::sync()
}
}
KResultOr<ByteBuffer> Inode::read_entire(FileDescription* descriptor) const
KResultOr<KBuffer> Inode::read_entire(FileDescription* descriptor) const
{
size_t initial_size = metadata().size ? metadata().size : 4096;
StringBuilder builder(initial_size);
KBufferBuilder builder;
ssize_t nread;
u8 buffer[4096];
@ -85,10 +85,10 @@ KResultOr<ByteBuffer> Inode::read_entire(FileDescription* descriptor) const
}
if (nread < 0) {
klog() << "Inode::read_entire: ERROR: " << nread;
return nullptr;
return KResult(nread);
}
return builder.to_byte_buffer();
return builder.build();
}
KResultOr<NonnullRefPtr<Custody>> Inode::resolve_as_link(Custody& base, RefPtr<Custody>* out_parent, int options, int symlink_recursion_level) const
@ -101,12 +101,6 @@ KResultOr<NonnullRefPtr<Custody>> Inode::resolve_as_link(Custody& base, RefPtr<C
return contents_or.error();
auto& contents = contents_or.value();
if (!contents) {
if (out_parent)
*out_parent = nullptr;
return KResult(-ENOENT);
}
auto path = StringView(contents.data(), contents.size());
return VFS::the().resolve_path(path, base, out_parent, options, symlink_recursion_level);
}

2
Kernel/FileSystem/Inode.h
View file

@ -67,7 +67,7 @@ public:
InodeIdentifier identifier() const { return { fsid(), index() }; }
virtual InodeMetadata metadata() const = 0;
KResultOr<ByteBuffer> read_entire(FileDescription* = nullptr) const;
KResultOr<KBuffer> read_entire(FileDescription* = nullptr) const;
virtual ssize_t read_bytes(off_t, ssize_t, u8* buffer, FileDescription*) const = 0;
virtual KResult traverse_as_directory(Function<bool(const FS::DirectoryEntry&)>) const = 0;