system/dev/block/fvm/fvm-private.h

// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#pragma once

#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>

#include <ddk/device.h>
#include <fvm/fvm.h>
#include <zircon/device/block.h>
#include <zircon/thread_annotations.h>
#include <zircon/types.h>

#ifdef __cplusplus

#include <atomic>
#include <ddktl/device.h>
#include <ddktl/protocol/block.h>
#include <ddktl/protocol/block/partition.h>
#include <fbl/algorithm.h>
#include <fbl/intrusive_wavl_tree.h>
#include <fbl/mutex.h>
#include <fbl/unique_ptr.h>
#include <fbl/vector.h>
#include <lib/fzl/owned-vmo-mapper.h>
#include <lib/zx/vmo.h>

#include "slice-extent.h"
#include "vpartition.h"

namespace fvm {

// Forward declaration
class VPartitionManager;
using ManagerDeviceType = ddk::Device<VPartitionManager, ddk::Ioctlable, ddk::Unbindable>;

class VPartitionManager : public ManagerDeviceType {
public:
    DISALLOW_COPY_ASSIGN_AND_MOVE(VPartitionManager);
    static zx_status_t Bind(zx_device_t* dev);

    // Read the underlying block device, initialize the recorded VPartitions.
    zx_status_t Load();

    // Block Protocol
    size_t BlockOpSize() const { return block_op_size_; }
    void Queue(block_op_t* txn, block_impl_queue_callback completion_cb, void* cookie) const {
        bp_.ops->queue(bp_.ctx, txn, completion_cb, cookie);
    }

    // Acquire access to a VPart Entry which has already been modified (and
    // will, as a consequence, not be de-allocated underneath us).
    vpart_entry_t* GetAllocatedVPartEntry(size_t index) const TA_NO_THREAD_SAFETY_ANALYSIS {
        auto entry = GetVPartEntryLocked(index);
        ZX_DEBUG_ASSERT(entry->slices > 0);
        return entry;
    }

    // Allocate 'count' slices, write back the FVM.
    zx_status_t AllocateSlices(VPartition* vp, size_t vslice_start, size_t count) TA_EXCL(lock_);

    // Deallocate 'count' slices, write back the FVM.
    // If a request is made to remove vslice_count = 0, deallocates the entire
    // VPartition.
    zx_status_t FreeSlices(VPartition* vp, size_t vslice_start, size_t count) TA_EXCL(lock_);

    // Returns global information about the FVM.
    void Query(fvm_info_t* info) TA_EXCL(lock_);

    size_t DiskSize() const { return info_.block_count * info_.block_size; }
    size_t SliceSize() const { return slice_size_; }
    size_t VSliceMax() const { return VSLICE_MAX; }
    const block_info_t& Info() const { return info_; }

    zx_status_t DdkIoctl(uint32_t op, const void* cmd, size_t cmdlen, void* reply, size_t max,
                         size_t* out_actual);
    void DdkUnbind();
    void DdkRelease();

    VPartitionManager(zx_device_t* dev, const block_info_t& info, size_t block_op_size,
                      const block_impl_protocol_t* bp);
    ~VPartitionManager();

private:
    // Marks the partition with instance GUID |old_guid| as inactive,
    // and marks partitions with instance GUID |new_guid| as active.
    //
    // If a partition with |old_guid| does not exist, it is ignored.
    // If |old_guid| equals |new_guid|, then |old_guid| is ignored.
    // If a partition with |new_guid| does not exist, |ZX_ERR_NOT_FOUND|
    // is returned.
    //
    // Updates the FVM metadata atomically.
    zx_status_t Upgrade(const uint8_t* old_guid, const uint8_t* new_guid) TA_EXCL(lock_);

    // Given a VPartition object, add a corresponding ddk device.
    zx_status_t AddPartition(fbl::unique_ptr<VPartition> vp) const;

    // Update, hash, and write back the current copy of the FVM metadata.
    // Automatically handles alternating writes to primary / backup copy of FVM.
    zx_status_t WriteFvmLocked() TA_REQ(lock_);

    zx_status_t AllocateSlicesLocked(VPartition* vp, size_t vslice_start, size_t count)
        TA_REQ(lock_);

    zx_status_t FreeSlicesLocked(VPartition* vp, size_t vslice_start, size_t count) TA_REQ(lock_);

    zx_status_t FindFreeVPartEntryLocked(size_t* out) const TA_REQ(lock_);
    zx_status_t FindFreeSliceLocked(size_t* out, size_t hint) const TA_REQ(lock_);

    fvm_t* GetFvmLocked() const TA_REQ(lock_) {
        return reinterpret_cast<fvm_t*>(metadata_.start());
    }

    // Mark a slice as free in the metadata structure.
    // Update free slice accounting.
    void FreePhysicalSlice(VPartition* vp, size_t pslice) TA_REQ(lock_);

    // Mark a slice as allocated in the metadata structure.
    // Update allocated slice accounting.
    void AllocatePhysicalSlice(VPartition* vp, size_t pslice, uint64_t vslice) TA_REQ(lock_);

    // Given a physical slice (acting as an index into the slice table),
    // return the associated slice entry.
    slice_entry_t* GetSliceEntryLocked(size_t index) const TA_REQ(lock_);

    // Given an index into the vpartition table, return the associated
    // virtual partition entry.
    vpart_entry_t* GetVPartEntryLocked(size_t index) const TA_REQ(lock_);

    size_t PrimaryOffsetLocked() const TA_REQ(lock_) {
        return first_metadata_is_primary_ ? 0 : MetadataSize();
    }

    size_t BackupOffsetLocked() const TA_REQ(lock_) {
        return first_metadata_is_primary_ ? MetadataSize() : 0;
    }

    size_t MetadataSize() const { return metadata_size_; }

    zx_status_t DoIoLocked(zx_handle_t vmo, size_t off, size_t len, uint32_t command);

    thrd_t initialization_thread_;
    block_info_t info_; // Cached info from parent device

    fbl::Mutex lock_;
    fzl::OwnedVmoMapper metadata_ TA_GUARDED(lock_);
    bool first_metadata_is_primary_ TA_GUARDED(lock_);
    size_t metadata_size_;
    size_t slice_size_;
    // Number of allocatable slices.
    size_t pslice_total_count_;
    // Number of currently allocated slices.
    size_t pslice_allocated_count_ TA_GUARDED(lock_);

    // Block Protocol
    const size_t block_op_size_;
    block_impl_protocol_t bp_;

    // Lock used to prevent multiple device remove calls.
    std::atomic<bool> device_remove_ = false;
};

} // namespace fvm

#endif // ifdef __cplusplus

__BEGIN_CDECLS

/////////////////// C-compatibility definitions (Provided to C from C++)

// Binds FVM driver to a device; loads the VPartition devices asynchronously in
// a background thread.
zx_status_t fvm_bind(zx_device_t* dev);

__END_CDECLS