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MontaukOS/kernel/src/Fs/FsProbe.cpp
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/*
* FsProbe.cpp
* Filesystem probe registry
* Copyright (c) 2026 Daniel Hammer
*/
#include "FsProbe.hpp"
#include <Drivers/Storage/Gpt.hpp>
#include <Drivers/Storage/BlockDevice.hpp>
#include <Terminal/Terminal.hpp>
#include <Libraries/Memory.hpp>
namespace Fs::FsProbe {
static ProbeFn g_probes[MaxProbes] = {};
static int g_probeCount = 0;
static bool g_mounted[Drivers::Storage::Gpt::MaxPartitions] = {};
static int g_driveForPart[Drivers::Storage::Gpt::MaxPartitions] = {};
void Register(ProbeFn fn) {
if (g_probeCount < MaxProbes && fn) {
g_probes[g_probeCount++] = fn;
}
}
static bool IsEfiPartition(const Drivers::Storage::Gpt::PartitionInfo* part) {
auto& a = part->TypeGuid;
auto& b = Drivers::Storage::Gpt::GUID_EFI_SYSTEM;
return a.Data1 == b.Data1 && a.Data2 == b.Data2 && a.Data3 == b.Data3 &&
memcmp(a.Data4, b.Data4, 8) == 0;
}
static int TryMountPartitionAtLowestDrive(int partIndex, int firstDrive, bool efiLog) {
if (!Vfs::IsInitialized()) return 0;
if (partIndex < 0 || partIndex >= Drivers::Storage::Gpt::MaxPartitions) return 0;
if (g_mounted[partIndex]) return 0;
auto* part = Drivers::Storage::Gpt::GetPartition(partIndex);
if (!part) return 0;
int driveNum = Vfs::FindLowestAvailableDrive(firstDrive);
if (driveNum < 0) {
Kt::KernelLogStream(Kt::WARNING, "FsProbe") << "No free drive slot for partition "
<< partIndex;
return -1;
}
for (int p = 0; p < g_probeCount; p++) {
Vfs::FsDriver* driver = g_probes[p](
part->BlockDevIndex, part->StartLba, part->SectorCount);
if (!driver) continue;
if (Vfs::RegisterDrive(driveNum, driver) == 0) {
g_mounted[partIndex] = true;
g_driveForPart[partIndex] = driveNum;
Kt::KernelLogStream(Kt::OK, "FsProbe")
<< (efiLog ? "Mounted EFI partition " : "Mounted partition ")
<< partIndex << " as drive " << driveNum;
return 1;
}
return -1;
}
Kt::KernelLogStream(Kt::INFO, "FsProbe") << "No filesystem recognized on partition "
<< partIndex;
return 0;
}
void MountPartitions(int firstDrive) {
int partCount = Drivers::Storage::Gpt::GetPartitionCount();
if (partCount == 0 || g_probeCount == 0) return;
// First pass: mount non-EFI partitions so they get lower drive numbers.
for (int i = 0; i < partCount; i++) {
auto* part = Drivers::Storage::Gpt::GetPartition(i);
if (!part || IsEfiPartition(part)) continue;
TryMountPartitionAtLowestDrive(i, firstDrive, false);
}
// Second pass: mount EFI system partitions after all others.
for (int i = 0; i < partCount; i++) {
auto* part = Drivers::Storage::Gpt::GetPartition(i);
if (!part || !IsEfiPartition(part)) continue;
TryMountPartitionAtLowestDrive(i, firstDrive, true);
}
}
int MountPartitionsForBlockDevice(int blockDevIndex, int firstDrive) {
if (!Vfs::IsInitialized() || g_probeCount == 0) return 0;
int partCount = Drivers::Storage::Gpt::GetPartitionCount();
int mounted = 0;
for (int i = 0; i < partCount; i++) {
auto* part = Drivers::Storage::Gpt::GetPartition(i);
if (!part || part->BlockDevIndex != blockDevIndex || IsEfiPartition(part)) continue;
int result = TryMountPartitionAtLowestDrive(i, firstDrive, false);
if (result > 0) mounted += result;
}
for (int i = 0; i < partCount; i++) {
auto* part = Drivers::Storage::Gpt::GetPartition(i);
if (!part || part->BlockDevIndex != blockDevIndex || !IsEfiPartition(part)) continue;
int result = TryMountPartitionAtLowestDrive(i, firstDrive, true);
if (result > 0) mounted += result;
}
return mounted;
}
int MountPartition(int partIndex, int driveNum) {
if (driveNum < 0 || driveNum >= Vfs::MaxDrives) return -1;
if (g_probeCount == 0) return -1;
if (partIndex >= 0 && partIndex < Drivers::Storage::Gpt::MaxPartitions && g_mounted[partIndex]) return -1;
if (Vfs::IsDriveRegistered(driveNum)) return -1;
auto* part = Drivers::Storage::Gpt::GetPartition(partIndex);
if (!part) return -1;
for (int p = 0; p < g_probeCount; p++) {
Vfs::FsDriver* driver = g_probes[p](
part->BlockDevIndex, part->StartLba, part->SectorCount);
if (driver) {
if (Vfs::RegisterDrive(driveNum, driver) == 0) {
if (partIndex >= 0 && partIndex < Drivers::Storage::Gpt::MaxPartitions) {
g_mounted[partIndex] = true;
g_driveForPart[partIndex] = driveNum;
}
Kt::KernelLogStream(Kt::OK, "FsProbe") << "Mounted partition "
<< partIndex << " as drive " << driveNum;
return 0;
}
return -1;
}
}
Kt::KernelLogStream(Kt::WARNING, "FsProbe") << "No filesystem recognized on partition " << partIndex;
return -1;
}
int GetBlockDeviceForDrive(int driveNum) {
if (driveNum < 0) return -1;
int partCount = Drivers::Storage::Gpt::GetPartitionCount();
for (int i = 0; i < partCount && i < Drivers::Storage::Gpt::MaxPartitions; i++) {
if (g_mounted[i] && g_driveForPart[i] == driveNum) {
auto* part = Drivers::Storage::Gpt::GetPartition(i);
if (part) return part->BlockDevIndex;
}
}
return -1;
}
int UnmountPartitionsForBlockDevice(int blockDevIndex) {
int partCount = Drivers::Storage::Gpt::GetPartitionCount();
int unmounted = 0;
int dst = 0;
for (int src = 0; src < partCount; src++) {
auto* part = Drivers::Storage::Gpt::GetPartition(src);
bool remove = part && part->BlockDevIndex == blockDevIndex;
if (remove) {
if (src < Drivers::Storage::Gpt::MaxPartitions &&
g_mounted[src] && g_driveForPart[src] >= 0) {
if (Vfs::UnregisterDrive(g_driveForPart[src]) == 0) {
unmounted++;
}
}
if (src < Drivers::Storage::Gpt::MaxPartitions) {
g_mounted[src] = false;
g_driveForPart[src] = -1;
}
continue;
}
if (src < Drivers::Storage::Gpt::MaxPartitions &&
dst < Drivers::Storage::Gpt::MaxPartitions) {
if (dst != src) {
g_mounted[dst] = g_mounted[src];
g_driveForPart[dst] = g_driveForPart[src];
}
dst++;
}
}
for (int i = dst; i < partCount && i < Drivers::Storage::Gpt::MaxPartitions; i++) {
g_mounted[i] = false;
g_driveForPart[i] = -1;
}
return unmounted;
}
int SyncAndUnmountAll() {
// 1. Flush every block device's volatile write cache to media. FAT32 and
// ext2 are write-through, so file data already reached the device; the
// flush makes the device commit it to non-volatile storage.
int devCount = Drivers::Storage::GetBlockDeviceCount();
for (int i = 0; i < devCount; i++) {
const auto* dev = Drivers::Storage::GetBlockDevice(i);
if (dev && dev->Flush) {
dev->Flush(dev->Ctx);
}
}
// 2. Cleanly unmount every disk-backed VFS drive. The ramdisk has no
// backing block device (GetBlockDeviceForDrive < 0) and is left
// mounted so the rest of userspace keeps running until power-off.
int drives[Vfs::MaxDrives];
int n = Vfs::VfsDriveList(drives, Vfs::MaxDrives);
int unmounted = 0;
for (int i = 0; i < n; i++) {
int driveNum = drives[i];
if (GetBlockDeviceForDrive(driveNum) < 0) continue;
if (Vfs::UnregisterDrive(driveNum) == 0) {
unmounted++;
for (int p = 0; p < Drivers::Storage::Gpt::MaxPartitions; p++) {
if (g_mounted[p] && g_driveForPart[p] == driveNum) {
g_mounted[p] = false;
g_driveForPart[p] = -1;
}
}
}
}
Kt::KernelLogStream(Kt::OK, "FsProbe") << "Synced and unmounted "
<< unmounted << " disk-backed volume(s) for power-off";
return unmounted;
}
};