system/ulib/minfs/inode-manager.cpp

// Copyright 2018 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.

#include <stdlib.h>

#include <minfs/block-txn.h>

#include "inode-manager.h"

namespace minfs {

InodeManager::InodeManager() = default;
InodeManager::~InodeManager() = default;

zx_status_t InodeManager::Initialize(Bcache* bc, ReadTxn* txn,
                                     blk_t start_block, size_t inodes) {
    start_block_ = start_block;
#ifdef __Fuchsia__
    zx_status_t status;
    uint32_t inoblks = (static_cast<uint32_t>(inodes) + kMinfsInodesPerBlock - 1) /
            kMinfsInodesPerBlock;
    if ((status = fs::MappedVmo::Create(inoblks * kMinfsBlockSize, "minfs-inode-table",
                                        &inode_table_)) != ZX_OK) {
        return status;
    }

    vmoid_t vmoid;
    if ((status = bc->AttachVmo(inode_table_->GetVmo(), &vmoid)) != ZX_OK) {
        return status;
    }
    txn->Enqueue(vmoid, 0, start_block_, inoblks);
#else
    bc_ = bc;
#endif
    return ZX_OK;
}

void InodeManager::Update(WriteTxn* txn, ino_t ino, const minfs_inode_t* inode) {
    // Obtain the offset of the inode within its containing block
    const uint32_t off_of_ino = (ino % kMinfsInodesPerBlock) * kMinfsInodeSize;
    const blk_t inoblock_rel = ino / kMinfsInodesPerBlock;
    const blk_t inoblock_abs = inoblock_rel + start_block_;
    assert(inoblock_abs < kFVMBlockDataStart);
#ifdef __Fuchsia__
    void* inodata = (void*)((uintptr_t)(inode_table_->GetData()) +
                            (uintptr_t)(inoblock_rel * kMinfsBlockSize));
    memcpy((void*)((uintptr_t)inodata + off_of_ino), inode, kMinfsInodeSize);
    txn->Enqueue(inode_table_->GetVmo(), inoblock_rel, inoblock_abs, 1);
#else
    // Since host-side tools don't have "mapped vmos", just read / update /
    // write the single absolute inode block.
    uint8_t inodata[kMinfsBlockSize];
    bc_->Readblk(inoblock_abs, inodata);
    memcpy((void*)((uintptr_t)inodata + off_of_ino), inode, kMinfsInodeSize);
    bc_->Writeblk(inoblock_abs, inodata);
#endif
}

void InodeManager::Load(ino_t ino, minfs_inode_t* out) const {
    // obtain the block of the inode table we need
    uint32_t off_of_ino = (ino % kMinfsInodesPerBlock) * kMinfsInodeSize;
#ifdef __Fuchsia__
    void* inodata = (void*)((uintptr_t)(inode_table_->GetData()) +
                            (uintptr_t)((ino / kMinfsInodesPerBlock) * kMinfsBlockSize));
#else
    uint8_t inodata[kMinfsBlockSize];
    bc_->Readblk(start_block_ + (ino / kMinfsInodesPerBlock), inodata);
#endif
    const minfs_inode_t* inode = reinterpret_cast<const minfs_inode_t*>((uintptr_t)inodata +
                                                                        off_of_ino);
    memcpy(out, inode, kMinfsInodeSize);
}

zx_status_t InodeManager::Grow(size_t inodes) {
#ifdef __Fuchsia__
    uint32_t inoblks = (static_cast<uint32_t>(inodes) + kMinfsInodesPerBlock - 1) /
            kMinfsInodesPerBlock;
    if (inode_table_->Grow(inoblks * kMinfsBlockSize) != ZX_OK) {
        return ZX_ERR_NO_SPACE;
    }
    return ZX_OK;
#else
    return ZX_ERR_NO_SPACE;
#endif
}

} // namespace minfs