mirror of
https://github.com/genodelabs/genode.git
synced 2024-12-20 14:13:09 +00:00
330 lines
8.5 KiB
C++
330 lines
8.5 KiB
C++
/*
|
|
* \brief Block device file system
|
|
* \author Josef Soentgen
|
|
* \author Norman Feske
|
|
* \date 2013-12-20
|
|
*/
|
|
|
|
/*
|
|
* Copyright (C) 2013-2014 Genode Labs GmbH
|
|
*
|
|
* This file is part of the Genode OS framework, which is distributed
|
|
* under the terms of the GNU General Public License version 2.
|
|
*/
|
|
|
|
#ifndef _INCLUDE__VFS__BLOCK_FILE_SYSTEM_H_
|
|
#define _INCLUDE__VFS__BLOCK_FILE_SYSTEM_H_
|
|
|
|
#include <base/allocator_avl.h>
|
|
#include <block_session/connection.h>
|
|
#include <vfs/single_file_system.h>
|
|
|
|
namespace Vfs { class Block_file_system; }
|
|
|
|
|
|
class Vfs::Block_file_system : public Single_file_system
|
|
{
|
|
private:
|
|
|
|
struct Label
|
|
{
|
|
enum { LABEL_MAX_LEN = 64 };
|
|
char string[LABEL_MAX_LEN];
|
|
|
|
Label(Xml_node config)
|
|
{
|
|
string[0] = 0;
|
|
try { config.attribute("label").value(string, sizeof(string)); }
|
|
catch (...) { }
|
|
}
|
|
} _label;
|
|
|
|
/*
|
|
* Serialize access to packet stream of the block session
|
|
*/
|
|
Lock _lock;
|
|
|
|
char *_block_buffer;
|
|
unsigned _block_buffer_count;
|
|
|
|
Genode::Allocator_avl _tx_block_alloc;
|
|
Block::Connection _block;
|
|
Genode::size_t _block_size;
|
|
Block::sector_t _block_count;
|
|
Block::Session::Operations _block_ops;
|
|
Block::Session::Tx::Source *_tx_source;
|
|
|
|
bool _readable;
|
|
bool _writeable;
|
|
|
|
file_size _block_io(file_size nr, void *buf, file_size sz,
|
|
bool write, bool bulk = false)
|
|
{
|
|
Lock::Guard guard(_lock);
|
|
|
|
Block::Packet_descriptor::Opcode op;
|
|
op = write ? Block::Packet_descriptor::WRITE : Block::Packet_descriptor::READ;
|
|
|
|
file_size packet_size = bulk ? sz : _block_size;
|
|
file_size packet_count = bulk ? (sz / _block_size) : 1;
|
|
|
|
/* sanity check */
|
|
if (packet_count > _block_buffer_count) {
|
|
packet_size = _block_buffer_count * _block_size;
|
|
packet_count = _block_buffer_count;
|
|
}
|
|
|
|
Block::Packet_descriptor p(_tx_source->alloc_packet(packet_size), op,
|
|
nr, packet_count);
|
|
|
|
if (write)
|
|
Genode::memcpy(_tx_source->packet_content(p), buf, packet_size);
|
|
|
|
_tx_source->submit_packet(p);
|
|
p = _tx_source->get_acked_packet();
|
|
|
|
if (!p.succeeded()) {
|
|
PERR("Could not read block(s)");
|
|
_tx_source->release_packet(p);
|
|
return 0;
|
|
}
|
|
|
|
if (!write)
|
|
Genode::memcpy(buf, _tx_source->packet_content(p), packet_size);
|
|
|
|
_tx_source->release_packet(p);
|
|
return packet_size;
|
|
}
|
|
|
|
public:
|
|
|
|
Block_file_system(Xml_node config)
|
|
:
|
|
Single_file_system(NODE_TYPE_BLOCK_DEVICE, name(), config),
|
|
_label(config),
|
|
_block_buffer(0),
|
|
_block_buffer_count(1),
|
|
_tx_block_alloc(env()->heap()),
|
|
_block(&_tx_block_alloc, 128*1024, _label.string),
|
|
_tx_source(_block.tx()),
|
|
_readable(false),
|
|
_writeable(false)
|
|
{
|
|
try { config.attribute("block_buffer_count").value(&_block_buffer_count); }
|
|
catch (...) { }
|
|
|
|
_block.info(&_block_count, &_block_size, &_block_ops);
|
|
|
|
_readable = _block_ops.supported(Block::Packet_descriptor::READ);
|
|
_writeable = _block_ops.supported(Block::Packet_descriptor::WRITE);
|
|
|
|
_block_buffer = new (env()->heap()) char[_block_buffer_count * _block_size];
|
|
}
|
|
|
|
~Block_file_system()
|
|
{
|
|
destroy(env()->heap(), _block_buffer);
|
|
}
|
|
|
|
static char const *name() { return "block"; }
|
|
|
|
|
|
/*********************************
|
|
** Directory service interface **
|
|
*********************************/
|
|
|
|
Stat_result stat(char const *path, Stat &out) override
|
|
{
|
|
Stat_result const result = Single_file_system::stat(path, out);
|
|
out.size = _block_count * _block_size;
|
|
return result;
|
|
}
|
|
|
|
|
|
/********************************
|
|
** File I/O service interface **
|
|
********************************/
|
|
|
|
Write_result write(Vfs_handle *vfs_handle, char const *buf,
|
|
file_size count, file_size &out_count) override
|
|
{
|
|
if (!_writeable) {
|
|
PERR("block device is not writeable");
|
|
return WRITE_ERR_INVALID;
|
|
}
|
|
|
|
file_size seek_offset = vfs_handle->seek();
|
|
|
|
file_size written = 0;
|
|
while (count > 0) {
|
|
file_size displ = 0;
|
|
file_size length = 0;
|
|
file_size nbytes = 0;
|
|
file_size blk_nr = seek_offset / _block_size;
|
|
|
|
displ = seek_offset % _block_size;
|
|
|
|
if ((displ + count) > _block_size)
|
|
length = (_block_size - displ);
|
|
else
|
|
length = count;
|
|
|
|
/*
|
|
* We take a shortcut and write as much as possible without
|
|
* using the block buffer if the offset is aligned on a block
|
|
* boundary and the count is a multiple of the block size,
|
|
* e.g. 4K writes will be written at once.
|
|
*
|
|
* XXX this is quite hackish because we have to omit partial
|
|
* blocks at the end.
|
|
*/
|
|
if (displ == 0 && (count % _block_size) >= 0 && !(count < _block_size)) {
|
|
file_size bytes_left = count - (count % _block_size);
|
|
|
|
nbytes = _block_io(blk_nr, (void*)(buf + written),
|
|
bytes_left, true, true);
|
|
if (nbytes == 0) {
|
|
PERR("error while write block:%llu from block device",
|
|
blk_nr);
|
|
return WRITE_ERR_INVALID;
|
|
}
|
|
|
|
written += nbytes;
|
|
count -= nbytes;
|
|
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* The offset is not aligned on a block boundary. Therefore
|
|
* we need to read the block to the block buffer first and
|
|
* put the buffer content at the right offset before we can
|
|
* write the whole block back. In addition if length is less
|
|
* than block size, we also have to read the block first.
|
|
*/
|
|
if (displ > 0 || length < _block_size) {
|
|
PWRN("offset:%llu block_size:%zd displacement:%llu length:%llu",
|
|
seek_offset, _block_size, displ, length);
|
|
|
|
_block_io(blk_nr, _block_buffer, _block_size, false);
|
|
/* rewind seek offset to account for the block read */
|
|
seek_offset -= _block_size;
|
|
}
|
|
|
|
Genode::memcpy(_block_buffer + displ, buf + written, length);
|
|
|
|
nbytes = _block_io(blk_nr, _block_buffer, _block_size, true);
|
|
if ((unsigned)nbytes != _block_size) {
|
|
PERR("error while writing block:%llu from Block_device",
|
|
blk_nr);
|
|
return WRITE_ERR_INVALID;
|
|
}
|
|
|
|
written += length;
|
|
count -= length;
|
|
}
|
|
|
|
out_count = written;
|
|
|
|
return WRITE_OK;
|
|
}
|
|
|
|
Read_result read(Vfs_handle *vfs_handle, char *dst, file_size count,
|
|
file_size &out_count) override
|
|
{
|
|
if (!_readable) {
|
|
PERR("block device is not readable");
|
|
return READ_ERR_INVALID;
|
|
}
|
|
|
|
file_size seek_offset = vfs_handle->seek();
|
|
|
|
file_size read = 0;
|
|
while (count > 0) {
|
|
file_size displ = 0;
|
|
file_size length = 0;
|
|
file_size nbytes = 0;
|
|
file_size blk_nr = seek_offset / _block_size;
|
|
|
|
displ = seek_offset % _block_size;
|
|
|
|
if ((displ + count) > _block_size)
|
|
length = (_block_size - displ);
|
|
else
|
|
length = count;
|
|
|
|
/*
|
|
* We take a shortcut and read the blocks all at once if t he
|
|
* offset is aligned on a block boundary and we the count is a
|
|
* multiple of the block size, e.g. 4K reads will be read at
|
|
* once.
|
|
*
|
|
* XXX this is quite hackish because we have to omit partial
|
|
* blocks at the end.
|
|
*/
|
|
if (displ == 0 && (count % _block_size) >= 0 && !(count < _block_size)) {
|
|
file_size bytes_left = count - (count % _block_size);
|
|
|
|
nbytes = _block_io(blk_nr, dst + read, bytes_left, false, true);
|
|
if (nbytes == 0) {
|
|
PERR("error while reading block:%llu from block device",
|
|
blk_nr);
|
|
return READ_ERR_INVALID;
|
|
}
|
|
|
|
read += nbytes;
|
|
count -= nbytes;
|
|
|
|
continue;
|
|
}
|
|
|
|
if (displ > 0)
|
|
PWRN("offset:%llu is not aligned to block_size:%zu"
|
|
" displacement:%llu", seek_offset, _block_size,
|
|
displ);
|
|
|
|
nbytes = _block_io(blk_nr, _block_buffer, _block_size, false);
|
|
if ((unsigned)nbytes != _block_size) {
|
|
PERR("error while reading block:%llu from block device",
|
|
blk_nr);
|
|
return READ_ERR_INVALID;
|
|
}
|
|
|
|
Genode::memcpy(dst + read, _block_buffer + displ, length);
|
|
|
|
read += length;
|
|
count -= length;
|
|
}
|
|
|
|
out_count = read;
|
|
|
|
return READ_OK;
|
|
}
|
|
|
|
Ftruncate_result ftruncate(Vfs_handle *vfs_handle, file_size) override
|
|
{
|
|
return FTRUNCATE_OK;
|
|
}
|
|
|
|
Ioctl_result ioctl(Vfs_handle *vfs_handle, Ioctl_opcode opcode, Ioctl_arg,
|
|
Ioctl_out &out) override
|
|
{
|
|
switch (opcode) {
|
|
case IOCTL_OP_DIOCGMEDIASIZE:
|
|
|
|
out.diocgmediasize.size = _block_count * _block_size;
|
|
return IOCTL_OK;
|
|
|
|
default:
|
|
|
|
PDBG("invalid ioctl request %d", opcode);
|
|
break;
|
|
}
|
|
|
|
/* never reached */
|
|
return IOCTL_ERR_INVALID;
|
|
}
|
|
};
|
|
|
|
#endif /* _INCLUDE__VFS__BLOCK_FILE_SYSTEM_H_ */
|