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support indirect datablock read/write

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This commit is contained in:
Ziao 2023-11-18 13:57:47 -08:00
parent c45667461b
commit a04c3d6334
1 changed files with 33 additions and 8 deletions
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41
lib/files.cpp
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@ -46,17 +46,43 @@ FilesOperation::FilesOperation(RawDisk& disk_): disk(disk_) {
inop.initialize(disk);
}
u_int64_t index_to_offset(disk& disk, u_int64_t index) {
if (index < 48) {
return inode.blocks[index];
} else if (index < 48 + 512){
char indirect_buffer[IO_BLOCK_SIZE] = {0};
disk.rawdisk_read(inode.single_indirect, indirect_buffer, IO_BLOCK_SIZE);
return INode::read_byte_at(8*(index-48), indirect_buffer);
} else if (index < 48 + 512 + 512*512) {
char indirect_buffer[IO_BLOCK_SIZE] = {0};
disk.rawdisk_read(inode.double_indirect, indirect_buffer, IO_BLOCK_SIZE);
u_int64_t offset = INode::read_byte_at(8*((index-48-512)/512), indirect_buffer);
disk.rawdisk_read(offset,indirect_buffer, IO_BLOCK_SIZE);
return INode::read_byte_at(8*((index-48-512)%512), indirect_buffer);
} else if (index < 48 + 512 + 512*512 + 512*512*512){
char indirect_buffer[IO_BLOCK_SIZE] = {0};
disk.rawdisk_read(inode.triple_indirect, indirect_buffer, IO_BLOCK_SIZE);
u_int64_t offset = INode::read_byte_at(8*((index-48-512-512*512)/(512*512)), indirect_buffer);
disk.rawdisk_read(offset,indirect_buffer, IO_BLOCK_SIZE);
offset = INode::read_byte_at(8*(((index-48-512-512*512)%(512*512))/512), indirect_buffer);
disk.rawdisk_read(offset,indirect_buffer, IO_BLOCK_SIZE);
return INode::read_byte_at(8*(((index-48-512-512*512)%512), indirect_buffer);
} else {
printf("index out of range, tried to access index %llu, max index %llu\n", index, 48+512+512*512+512*512*512);
return -1;
}
}
int FilesOperation::read_datablock(INode& inode, u_int64_t index, char* buffer) {
if (index >= inode.size) {
printf("Read datablock out of range, inode number %llu", inode.block_number);
return -1;
}
if (index < 48) {
return disk.rawdisk_read(inode.blocks[index], buffer, IO_BLOCK_SIZE);
} else {
perror("Read indirect datablocks not implemented yet");
u_int64_t read_offset = index_to_offset(disk, index);
if (read_offset == (u_int64_t)(-1)) {
return -1;
}
return disk.rawdisk_read(read_offset, buffer, IO_BLOCK_SIZE);
}
int FilesOperation::write_datablock(INode& inode, u_int64_t index, char* buffer) {
@ -64,12 +90,11 @@ int FilesOperation::write_datablock(INode& inode, u_int64_t index, char* buffer)
u_int64_t ret = inode.datablock_allocate(disk);
inode.size += 1;
}
if (index < 48) {
return disk.rawdisk_write(inode.blocks[index], buffer, IO_BLOCK_SIZE);
} else {
perror("Write indirect datablocks not implemented yet");
u_int64_t write_offset = index_to_offset(disk, index);
if (write_offset == (u_int64_t)(-1)) {
return -1;
}
return disk.rawdisk_read(write_offset, buffer, IO_BLOCK_SIZE);
}
INode* FilesOperation::new_inode(u_int64_t inode_number, u_int64_t permissions) {