mkfs: split into more helpers (and drop malloc just do seek instead)

This commit is contained in:
Azat Khuzhin 2014-07-12 17:38:22 +04:00
parent bb70d76497
commit 7610120b10

View File

@ -9,22 +9,138 @@
#include "simple.h"
const uint64_t WELCOMEFILE_DATABLOCK_NUMBER = 3;
const uint64_t WELCOMEFILE_INODE_NUMBER = 2;
static int write_superblock(int fd)
{
struct simplefs_super_block sb;
ssize_t ret;
sb.version = 1;
sb.magic = SIMPLEFS_MAGIC;
sb.block_size = SIMPLEFS_DEFAULT_BLOCK_SIZE;
/* One inode for rootdirectory and another for a welcome file that we are going to create */
sb.inodes_count = 2;
/* FIXME: Free blocks management is not implemented yet */
sb.free_blocks = ~0;
sb.free_blocks &= ~(1 << WELCOMEFILE_DATABLOCK_NUMBER);
ret = write(fd, &sb, sizeof(sb));
if (ret != SIMPLEFS_DEFAULT_BLOCK_SIZE) {
printf
("bytes written [%d] are not equal to the default block size\n",
(int)ret);
return -1;
}
printf("Super block written succesfully\n");
return 0;
}
static int write_inode_store(int fd)
{
ssize_t ret;
struct simplefs_inode root_inode;
root_inode.mode = S_IFDIR;
root_inode.inode_no = SIMPLEFS_ROOTDIR_INODE_NUMBER;
root_inode.data_block_number = SIMPLEFS_ROOTDIR_DATABLOCK_NUMBER;
root_inode.dir_children_count = 1;
ret = write(fd, &root_inode, sizeof(root_inode));
if (ret != sizeof(root_inode)) {
printf
("The inode store was not written properly. Retry your mkfs\n");
return -1;
}
printf("root directory inode written succesfully\n");
return 0;
}
static int write_inode(int fd, const struct simplefs_inode *i)
{
off_t nbytes;
ssize_t ret;
ret = write(fd, i, sizeof(*i));
if (ret != sizeof(*i)) {
printf
("The welcomefile inode was not written properly. Retry your mkfs\n");
return -1;
}
printf("welcomefile inode written succesfully\n");
nbytes = SIMPLEFS_DEFAULT_BLOCK_SIZE - sizeof(*i) - sizeof(*i);
ret = lseek(fd, nbytes, SEEK_CUR);
if (ret == (off_t)-1) {
printf
("The padding bytes are not written properly. Retry your mkfs\n");
return -1;
}
printf
("inode store padding bytes (after the two inodes) written sucessfully\n");
return 0;
}
int write_dirent(int fd, const struct simplefs_dir_record *record)
{
ssize_t nbytes = sizeof(*record), ret;
ret = write(fd, record, nbytes);
if (ret != nbytes) {
printf
("Writing the rootdirectory datablock (name+inode_no pair for welcomefile) has failed\n");
return -1;
}
printf
("root directory datablocks (name+inode_no pair for welcomefile) written succesfully\n");
nbytes = SIMPLEFS_DEFAULT_BLOCK_SIZE - sizeof(*record);
ret = lseek(fd, nbytes, SEEK_CUR);
if (ret == (off_t)-1) {
printf
("Writing the padding for rootdirectory children datablock has failed\n");
return -1;
}
printf
("padding after the rootdirectory children written succesfully\n");
return 0;
}
int write_block(int fd, char *block, size_t len)
{
ssize_t ret;
ret = write(fd, block, len);
if (ret != len) {
printf("Writing file body has failed\n");
return -1;
}
printf("block has been written succesfully\n");
return 0;
}
int main(int argc, char *argv[])
{
int fd, nbytes;
int fd;
ssize_t ret;
struct simplefs_super_block sb;
struct simplefs_inode root_inode;
struct simplefs_inode welcomefile_inode;
char welcomefile_name[] = "vanakkam";
char welcomefile_body[] = "Love is God. God is Love. Anbe Murugan.\n";
const uint64_t WELCOMEFILE_INODE_NUMBER = 2;
const uint64_t WELCOMEFILE_DATABLOCK_NUMBER = 3;
char *block_padding = NULL;
struct simplefs_dir_record record;
struct simplefs_inode welcome = {
.mode = S_IFREG,
.inode_no = WELCOMEFILE_INODE_NUMBER,
.data_block_number = WELCOMEFILE_DATABLOCK_NUMBER,
.file_size = sizeof(welcomefile_body),
};
struct simplefs_dir_record record = {
.filename = "vanakkam",
.inode_no = WELCOMEFILE_INODE_NUMBER,
};
if (argc != 2) {
printf("Usage: mkfs-simplefs <device>\n");
@ -37,126 +153,23 @@ int main(int argc, char *argv[])
return -1;
}
/* Begin writing of Block 0 - Super Block */
sb.version = 1;
sb.magic = SIMPLEFS_MAGIC;
sb.block_size = SIMPLEFS_DEFAULT_BLOCK_SIZE;
ret = 1;
do {
if (write_superblock(fd))
break;
if (write_inode_store(fd))
break;
/* One inode for rootdirectory and another for a welcome file that we are going to create */
sb.inodes_count = 2;
/* FIXME: Free blocks management is not implemented yet */
sb.free_blocks = ~0;
sb.free_blocks &= ~(1 << WELCOMEFILE_DATABLOCK_NUMBER);
ret = write(fd, (char *)&sb, sizeof(sb));
if (ret != SIMPLEFS_DEFAULT_BLOCK_SIZE) {
printf
("bytes written [%d] are not equal to the default block size\n",
(int)ret);
ret = -1;
goto exit;
}
printf("Super block written succesfully\n");
/* End of writing of Block 0 - Super block */
/* Begin writing of Block 1 - Inode Store */
root_inode.mode = S_IFDIR;
root_inode.inode_no = SIMPLEFS_ROOTDIR_INODE_NUMBER;
root_inode.data_block_number = SIMPLEFS_ROOTDIR_DATABLOCK_NUMBER;
root_inode.dir_children_count = 1;
ret = write(fd, (char *)&root_inode, sizeof(root_inode));
if (ret != sizeof(root_inode)) {
printf
("The inode store was not written properly. Retry your mkfs\n");
ret = -1;
goto exit;
}
printf("root directory inode written succesfully\n");
welcomefile_inode.mode = S_IFREG;
welcomefile_inode.inode_no = WELCOMEFILE_INODE_NUMBER;
welcomefile_inode.data_block_number = WELCOMEFILE_DATABLOCK_NUMBER;
welcomefile_inode.file_size = sizeof(welcomefile_body);
ret = write(fd, (char *)&welcomefile_inode, sizeof(root_inode));
if (ret != sizeof(root_inode)) {
printf
("The welcomefile inode was not written properly. Retry your mkfs\n");
ret = -1;
goto exit;
}
printf("welcomefile inode written succesfully\n");
nbytes =
SIMPLEFS_DEFAULT_BLOCK_SIZE - sizeof(root_inode) -
sizeof(welcomefile_inode);
block_padding = malloc(nbytes);
ret = write(fd, block_padding, nbytes);
if (ret != nbytes) {
printf
("The padding bytes are not written properly. Retry your mkfs\n");
ret = -1;
goto exit;
}
printf
("inode store padding bytes (after the two inodes) written sucessfully\n");
/* End of writing of Block 1 - inode Store */
/* Begin writing of Block 2 - Root Directory datablocks */
strcpy(record.filename, welcomefile_name);
record.inode_no = WELCOMEFILE_INODE_NUMBER;
nbytes = sizeof(record);
ret = write(fd, (char *)&record, nbytes);
if (ret != nbytes) {
printf
("Writing the rootdirectory datablock (name+inode_no pair for welcomefile) has failed\n");
ret = -1;
goto exit;
}
printf
("root directory datablocks (name+inode_no pair for welcomefile) written succesfully\n");
nbytes = SIMPLEFS_DEFAULT_BLOCK_SIZE - sizeof(record);
block_padding = realloc(block_padding, nbytes);
ret = write(fd, block_padding, nbytes);
if (ret != nbytes) {
printf
("Writing the padding for rootdirectory children datablock has failed\n");
ret = -1;
goto exit;
}
printf
("padding after the rootdirectory children written succesfully\n");
/* End of writing of Block 2 - Root directory contents */
/* Begin writing of Block 3 - Welcome file contents */
nbytes = sizeof(welcomefile_body);
ret = write(fd, welcomefile_body, nbytes);
if (ret != nbytes) {
printf("Writing welcomefile body has failed\n");
ret = -1;
goto exit;
}
printf("welcomefilebody has been written succesfully\n");
/* End of writing of Block 3 - Welcome file contents */
if (write_inode(fd, &welcome))
break;
if (write_dirent(fd, &record))
break;
if (write_block(fd, welcomefile_body, welcome.file_size))
break;
ret = 0;
} while (0);
exit:
if (block_padding) {
free(block_padding);
}
close(fd);
return ret;
}