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Kernel: Use ProtectedValue for VirtualFileSystem::m_mounts

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This is what VirtualFileSystem::m_lock was actually guarding, and
wrapping it in a ProtectedValue makes it so much more obvious how it
all works. :^)
This commit is contained in:
Andreas Kling 2021-08-16 01:40:19 +02:00
parent 7089135a07
commit 29a58459ab
2 changed files with 56 additions and 51 deletions
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100
Kernel/FileSystem/VirtualFileSystem.cpp
View file

@ -51,38 +51,36 @@ InodeIdentifier VirtualFileSystem::root_inode_id() const
KResult VirtualFileSystem::mount(FileSystem& fs, Custody& mount_point, int flags)
{
MutexLocker locker(m_lock);
auto& inode = mount_point.inode();
dbgln("VirtualFileSystem: Mounting {} at {} (inode: {}) with flags {}",
fs.class_name(),
mount_point.try_create_absolute_path(),
inode.identifier(),
flags);
// FIXME: check that this is not already a mount point
Mount mount { fs, &mount_point, flags };
m_mounts.append(move(mount));
return KSuccess;
return m_mounts.with_exclusive([&](auto& mounts) -> KResult {
auto& inode = mount_point.inode();
dbgln("VirtualFileSystem: Mounting {} at {} (inode: {}) with flags {}",
fs.class_name(),
mount_point.try_create_absolute_path(),
inode.identifier(),
flags);
// FIXME: check that this is not already a mount point
Mount mount { fs, &mount_point, flags };
mounts.append(move(mount));
return KSuccess;
});
}
KResult VirtualFileSystem::bind_mount(Custody& source, Custody& mount_point, int flags)
{
MutexLocker locker(m_lock);
dbgln("VirtualFileSystem: Bind-mounting {} at {}", source.try_create_absolute_path(), mount_point.try_create_absolute_path());
// FIXME: check that this is not already a mount point
Mount mount { source.inode(), mount_point, flags };
m_mounts.append(move(mount));
return KSuccess;
return m_mounts.with_exclusive([&](auto& mounts) -> KResult {
dbgln("VirtualFileSystem: Bind-mounting {} at {}", source.try_create_absolute_path(), mount_point.try_create_absolute_path());
// FIXME: check that this is not already a mount point
Mount mount { source.inode(), mount_point, flags };
mounts.append(move(mount));
return KSuccess;
});
}
KResult VirtualFileSystem::remount(Custody& mount_point, int new_flags)
{
MutexLocker locker(m_lock);
dbgln("VirtualFileSystem: Remounting {}", mount_point.try_create_absolute_path());
Mount* mount = find_mount_for_guest(mount_point.inode().identifier());
auto* mount = find_mount_for_guest(mount_point.inode().identifier());
if (!mount)
return ENODEV;
@ -92,24 +90,24 @@ KResult VirtualFileSystem::remount(Custody& mount_point, int new_flags)
KResult VirtualFileSystem::unmount(Inode& guest_inode)
{
MutexLocker locker(m_lock);
dbgln("VirtualFileSystem: unmount called with inode {}", guest_inode.identifier());
for (size_t i = 0; i < m_mounts.size(); ++i) {
auto& mount = m_mounts.at(i);
if (&mount.guest() == &guest_inode) {
return m_mounts.with_exclusive([&](auto& mounts) -> KResult {
for (size_t i = 0; i < mounts.size(); ++i) {
auto& mount = mounts[i];
if (&mount.guest() != &guest_inode)
continue;
if (auto result = mount.guest_fs().prepare_to_unmount(); result.is_error()) {
dbgln("VirtualFileSystem: Failed to unmount!");
return result;
}
dbgln("VirtualFileSystem: found fs {} at mount index {}! Unmounting...", mount.guest_fs().fsid(), i);
m_mounts.unstable_take(i);
dbgln("VirtualFileSystem: Unmounting file system {}...", mount.guest_fs().fsid());
mounts.unstable_take(i);
return KSuccess;
}
}
dbgln("VirtualFileSystem: Nothing mounted on inode {}", guest_inode.identifier());
return ENODEV;
dbgln("VirtualFileSystem: Nothing mounted on inode {}", guest_inode.identifier());
return ENODEV;
});
}
bool VirtualFileSystem::mount_root(FileSystem& fs)
@ -130,7 +128,9 @@ bool VirtualFileSystem::mount_root(FileSystem& fs)
m_root_inode = root_inode;
dmesgln("VirtualFileSystem: mounted root from {} ({})", fs.class_name(), static_cast<FileBackedFileSystem&>(fs).file_description().absolute_path());
m_mounts.append(move(mount));
m_mounts.with_exclusive([&](auto& mounts) {
mounts.append(move(mount));
});
auto custody_or_error = Custody::try_create(nullptr, "", *m_root_inode, root_mount_flags);
if (custody_or_error.is_error())
@ -141,20 +141,24 @@ bool VirtualFileSystem::mount_root(FileSystem& fs)
auto VirtualFileSystem::find_mount_for_host(InodeIdentifier id) -> Mount*
{
for (auto& mount : m_mounts) {
if (mount.host() && mount.host()->identifier() == id)
return &mount;
}
return nullptr;
return m_mounts.with_exclusive([&](auto& mounts) -> Mount* {
for (auto& mount : mounts) {
if (mount.host() && mount.host()->identifier() == id)
return &mount;
}
return nullptr;
});
}
auto VirtualFileSystem::find_mount_for_guest(InodeIdentifier id) -> Mount*
{
for (auto& mount : m_mounts) {
if (mount.guest().identifier() == id)
return &mount;
}
return nullptr;
return m_mounts.with_exclusive([&](auto& mounts) -> Mount* {
for (auto& mount : mounts) {
if (mount.guest().identifier() == id)
return &mount;
}
return nullptr;
});
}
bool VirtualFileSystem::is_vfs_root(InodeIdentifier inode) const
@ -795,11 +799,13 @@ KResult VirtualFileSystem::rmdir(StringView path, Custody& base)
return parent_inode.remove_child(KLexicalPath::basename(path));
}
void VirtualFileSystem::for_each_mount(Function<void(const Mount&)> callback) const
void VirtualFileSystem::for_each_mount(Function<void(Mount const&)> callback) const
{
for (auto& mount : m_mounts) {
callback(mount);
}
m_mounts.with_shared([&](auto& mounts) {
for (auto& mount : mounts) {
callback(mount);
}
});
}
void VirtualFileSystem::sync()