ladybird/Kernel/FileSystem/FileBackedFileSystem.cpp

/*
 * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <Kernel/FileSystem/FileBackedFileSystem.h>

namespace Kernel {

FileBackedFileSystem::FileBackedFileSystem(OpenFileDescription& file_description)
    : m_file_description(file_description)
{
}

FileBackedFileSystem::~FileBackedFileSystem() = default;

ErrorOr<void> FileBackedFileSystem::initialize()
{
    MutexLocker locker(m_lock);
    if (is_initialized_while_locked())
        return {};
    return initialize_while_locked();
}

}
Meta: Add license header to source files As suggested by Joshua, this commit adds the 2-clause BSD license as a comment block to the top of every source file. For the first pass, I've just added myself for simplicity. I encourage everyone to add themselves as copyright holders of any file they've added or modified in some significant way. If I've added myself in error somewhere, feel free to replace it with the appropriate copyright holder instead. Going forward, all new source files should include a license header. 2020-01-18 11:38:21 +03:00			`/*`
Kernel: Rename FileBackedFS => FileBackedFileSystem 2021-07-11 01:33:27 +03:00			`* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>`
Meta: Add license header to source files As suggested by Joshua, this commit adds the 2-clause BSD license as a comment block to the top of every source file. For the first pass, I've just added myself for simplicity. I encourage everyone to add themselves as copyright holders of any file they've added or modified in some significant way. If I've added myself in error somewhere, feel free to replace it with the appropriate copyright holder instead. Going forward, all new source files should include a license header. 2020-01-18 11:38:21 +03:00			`*`
Everything: Move to SPDX license identifiers in all files. SPDX License Identifiers are a more compact / standardized way of representing file license information. See: https://spdx.dev/resources/use/#identifiers This was done with the `ambr` search and replace tool. ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt * 2021-04-22 11:24:48 +03:00			`* SPDX-License-Identifier: BSD-2-Clause`
Meta: Add license header to source files As suggested by Joshua, this commit adds the 2-clause BSD license as a comment block to the top of every source file. For the first pass, I've just added myself for simplicity. I encourage everyone to add themselves as copyright holders of any file they've added or modified in some significant way. If I've added myself in error somewhere, feel free to replace it with the appropriate copyright holder instead. Going forward, all new source files should include a license header. 2020-01-18 11:38:21 +03:00			`*/`

Kernel: Change Ext2FS to be backed by a file instead of a block device In contrast to the previous patchset that was reverted, this time we use a "special" method to access a file with block size of 512 bytes (like a harddrive essentially). 2020-04-06 11:54:21 +03:00			`#include <Kernel/FileSystem/FileBackedFileSystem.h>`
Import all this stuff into a single repo called Serenity. 2018-10-10 12:53:07 +03:00
Kernel: Move all code into the Kernel namespace 2020-02-16 03:27:42 +03:00			`namespace Kernel {`

Kernel: Rename FileDescription => OpenFileDescription Dr. POSIX really calls these "open file description", not just "file description", so let's call them exactly that. :^) 2021-09-07 14:39:11 +03:00			`FileBackedFileSystem::FileBackedFileSystem(OpenFileDescription& file_description)`
Kernel: Change Ext2FS to be backed by a file instead of a block device In contrast to the previous patchset that was reverted, this time we use a "special" method to access a file with block size of 512 bytes (like a harddrive essentially). 2020-04-06 11:54:21 +03:00			`: m_file_description(file_description)`
Import all this stuff into a single repo called Serenity. 2018-10-10 12:53:07 +03:00			`{`
			`}`

Kernel: Use default constructors/destructors https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#cother-other-default-operation-rules "The compiler is more likely to get the default semantics right and you cannot implement these functions better than the compiler." 2022-03-16 22:15:15 +03:00			`FileBackedFileSystem::~FileBackedFileSystem() = default;`
Import all this stuff into a single repo called Serenity. 2018-10-10 12:53:07 +03:00
Kernel: Introduce support for using FileSystem object in multiple mounts The idea is to enable mounting FileSystem objects across multiple mounts in contrast to what happened until now - each mount has its own unique FileSystem object being attached to it. Considering a situation of mounting a block device at 2 different mount points at in system, there were a couple of critical flaws due to how the previous "design" worked: 1. BlockBasedFileSystem(s) that pointed to the same actual device had a separate DiskCache object being attached to them. Because both instances were not synchronized by any means, corruption of the filesystem is most likely achieveable by a simple cache flush of either of the instances. 2. For superblock-oriented filesystems (such as the ext2 filesystem), lack of synchronization between both instances can lead to severe corruption in the superblock, which could render the entire filesystem unusable. 3. Flags of a specific filesystem implementation (for example, with xfs on Linux, one can instruct to mount it with the discard option) must be honored across multiple mounts, to ensure expected behavior against a particular filesystem. This patch put the foundations to start fix the issues mentioned above. However, there are still major issues to solve, so this is only a start. 2022-08-20 00:03:24 +03:00			`ErrorOr<void> FileBackedFileSystem::initialize()`
			`{`
			`MutexLocker locker(m_lock);`
			`if (is_initialized_while_locked())`
			`return {};`
			`return initialize_while_locked();`
			`}`

Kernel: Move all code into the Kernel namespace 2020-02-16 03:27:42 +03:00			`}`