mirrors/ladybird
0
0
Fork 0
mirror of https://github.com/LadybirdBrowser/ladybird.git synced 2025-04-26 14:28:49 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 9

Kernel/FileSystem: Discard safely filesystems when unmounted last time

Browse source 
This commit reached that goal of "safely discarding" a filesystem by
doing the following:
1. Stop using the s_file_system_map HashMap as it was an unsafe measure
to access pointers of FileSystems. Instead, make sure to register all
FileSystems at the VFS layer, with an IntrusiveList, to avoid problems
related to OOM conditions.
2. Make sure to cleanly remove the DiskCache object from a BlockBased
filesystem, so the destructor of such object will not need to do that in
the destruction point.
3. For ext2 filesystems, don't cache the root inode at m_inode_cache
HashMap. The reason for this is that when unmounting an ext2 filesystem,
we lookup at the cache to see if there's a reference to a cached inode
and if that's the case, we fail with EBUSY. If we keep the m_root_inode
also being referenced at the m_inode_cache map, we have 2 references to
that object, which will lead to fail with EBUSY. Also, it's much simpler
to always ask for a root inode and get it immediately from m_root_inode,
instead of looking up the cache for that inode.
This commit is contained in:
Liav A 2022-08-20 09:28:02 +03:00 • committed by Andrew Kaster
parent 24977996a6
commit fea3cb5ff9
Notes: sideshowbarker 2024-07-17 05:12:43 +09:00
9 changed files with 103 additions and 54 deletions
Download patch file Download diff file Expand all files Collapse all files

62
Kernel/FileSystem/VirtualFileSystem.cpp
View file

@ -111,6 +111,30 @@ ErrorOr<void> VirtualFileSystem::remount(Custody& mount_point, int new_flags)
return {};
}
void VirtualFileSystem::sync_filesystems()
{
NonnullLockRefPtrVector<FileSystem, 32> file_systems;
m_file_systems_list.with([&](auto const& list) {
for (auto& fs : list)
file_systems.append(fs);
});
for (auto& fs : file_systems)
fs.flush_writes();
}
void VirtualFileSystem::lock_all_filesystems()
{
NonnullLockRefPtrVector<FileSystem, 32> file_systems;
m_file_systems_list.with([&](auto const& list) {
for (auto& fs : list)
file_systems.append(fs);
});
for (auto& fs : file_systems)
fs.m_lock.lock();
}
ErrorOr<void> VirtualFileSystem::unmount(Custody& mountpoint_custody)
{
auto& guest_inode = mountpoint_custody.inode();
@ -125,11 +149,27 @@ ErrorOr<void> VirtualFileSystem::unmount(Custody& mountpoint_custody)
auto mountpoint_path = TRY(mount->absolute_path());
if (custody_path->view() != mountpoint_path->view())
continue;
TRY(mount->guest_fs().prepare_to_unmount());
mount->guest_fs().mounted_count({}).with([&](auto& mounted_count) {
mounted_count--;
NonnullRefPtr<FileSystem> fs = mount->guest_fs();
TRY(fs->prepare_to_unmount());
fs->mounted_count({}).with([&](auto& mounted_count) {
VERIFY(mounted_count > 0);
if (mounted_count == 1) {
dbgln("VirtualFileSystem: Unmounting file system {} for the last time...", fs->fsid());
m_file_systems_list.with([&](auto& list) {
list.remove(*fs);
});
if (fs->is_file_backed()) {
dbgln("VirtualFileSystem: Unmounting file backed file system {} for the last time...", fs->fsid());
auto& file_backed_fs = static_cast<FileBackedFileSystem&>(*fs);
m_file_backed_file_systems_list.with([&](auto& list) {
list.remove(file_backed_fs);
});
}
} else {
mounted_count--;
}
});
dbgln("VirtualFileSystem: Unmounting file system {}...", mount->guest_fs().fsid());
dbgln("VirtualFileSystem: Unmounting file system {}...", fs->fsid());
(void)mounts.unstable_take(i);
return {};
}
@ -154,15 +194,20 @@ ErrorOr<void> VirtualFileSystem::mount_root(FileSystem& fs)
}
m_root_inode = root_inode;
auto pseudo_path = TRY(static_cast<FileBackedFileSystem&>(fs).file_description().pseudo_path());
dmesgln("VirtualFileSystem: mounted root({}) from {} ({})", fs.fsid(), fs.class_name(), pseudo_path);
if (fs.is_file_backed()) {
auto pseudo_path = TRY(static_cast<FileBackedFileSystem&>(fs).file_description().pseudo_path());
dmesgln("VirtualFileSystem: mounted root({}) from {} ({})", fs.fsid(), fs.class_name(), pseudo_path);
m_file_backed_file_systems_list.with([&](auto& list) {
list.append(static_cast<FileBackedFileSystem&>(fs));
});
} else {
dmesgln("VirtualFileSystem: mounted root({}) from {}", fs.fsid(), fs.class_name());
}
m_file_systems_list.with([&](auto& fs_list) {
fs_list.append(fs);
});
// Note: Actually add a mount for the filesystem and increment the filesystem mounted count
m_mounts.with([&](auto& mounts) {
new_mount->guest_fs().mounted_count({}).with([&](auto& mounted_count) {
@ -278,6 +323,9 @@ ErrorOr<NonnullLockRefPtr<FileBackedFileSystem>> VirtualFileSystem::find_already
auto fs = TRY(callback(description));
VERIFY(fs->is_file_backed());
list.append(static_cast<FileBackedFileSystem&>(*fs));
m_file_systems_list.with([&](auto& fs_list) {
fs_list.append(*fs);
});
return static_ptr_cast<FileBackedFileSystem>(fs);
}));
}