mirror of
https://github.com/psankar/simplefs.git
synced 2025-07-26 07:24:53 +02:00
mkfs: split into more helpers (and drop malloc just do seek instead)
This commit is contained in:
Azat Khuzhin
parent
bb70d76497
commit
7610120b10
267
mkfs-simplefs.c
267
mkfs-simplefs.c
@ -9,22 +9,138 @@
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#include "simple.h"
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const uint64_t WELCOMEFILE_DATABLOCK_NUMBER = 3;
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const uint64_t WELCOMEFILE_INODE_NUMBER = 2;
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static int write_superblock(int fd)
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{
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struct simplefs_super_block sb;
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ssize_t ret;
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sb.version = 1;
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sb.magic = SIMPLEFS_MAGIC;
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sb.block_size = SIMPLEFS_DEFAULT_BLOCK_SIZE;
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/* One inode for rootdirectory and another for a welcome file that we are going to create */
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sb.inodes_count = 2;
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/* FIXME: Free blocks management is not implemented yet */
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sb.free_blocks = ~0;
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sb.free_blocks &= ~(1 << WELCOMEFILE_DATABLOCK_NUMBER);
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ret = write(fd, &sb, sizeof(sb));
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if (ret != SIMPLEFS_DEFAULT_BLOCK_SIZE) {
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printf
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("bytes written [%d] are not equal to the default block size\n",
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(int)ret);
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return -1;
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}
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printf("Super block written succesfully\n");
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return 0;
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}
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static int write_inode_store(int fd)
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{
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ssize_t ret;
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struct simplefs_inode root_inode;
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root_inode.mode = S_IFDIR;
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root_inode.inode_no = SIMPLEFS_ROOTDIR_INODE_NUMBER;
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root_inode.data_block_number = SIMPLEFS_ROOTDIR_DATABLOCK_NUMBER;
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root_inode.dir_children_count = 1;
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ret = write(fd, &root_inode, sizeof(root_inode));
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if (ret != sizeof(root_inode)) {
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printf
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("The inode store was not written properly. Retry your mkfs\n");
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return -1;
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}
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printf("root directory inode written succesfully\n");
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return 0;
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}
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static int write_inode(int fd, const struct simplefs_inode *i)
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{
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off_t nbytes;
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ssize_t ret;
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ret = write(fd, i, sizeof(*i));
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if (ret != sizeof(*i)) {
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printf
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("The welcomefile inode was not written properly. Retry your mkfs\n");
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return -1;
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}
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printf("welcomefile inode written succesfully\n");
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nbytes = SIMPLEFS_DEFAULT_BLOCK_SIZE - sizeof(*i) - sizeof(*i);
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ret = lseek(fd, nbytes, SEEK_CUR);
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if (ret == (off_t)-1) {
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printf
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("The padding bytes are not written properly. Retry your mkfs\n");
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return -1;
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}
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printf
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("inode store padding bytes (after the two inodes) written sucessfully\n");
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return 0;
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}
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int write_dirent(int fd, const struct simplefs_dir_record *record)
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{
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ssize_t nbytes = sizeof(*record), ret;
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ret = write(fd, record, nbytes);
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if (ret != nbytes) {
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printf
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("Writing the rootdirectory datablock (name+inode_no pair for welcomefile) has failed\n");
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return -1;
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}
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printf
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("root directory datablocks (name+inode_no pair for welcomefile) written succesfully\n");
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nbytes = SIMPLEFS_DEFAULT_BLOCK_SIZE - sizeof(*record);
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ret = lseek(fd, nbytes, SEEK_CUR);
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if (ret == (off_t)-1) {
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printf
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("Writing the padding for rootdirectory children datablock has failed\n");
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return -1;
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}
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printf
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("padding after the rootdirectory children written succesfully\n");
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return 0;
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}
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int write_block(int fd, char *block, size_t len)
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{
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ssize_t ret;
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ret = write(fd, block, len);
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if (ret != len) {
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printf("Writing file body has failed\n");
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return -1;
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}
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printf("block has been written succesfully\n");
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return 0;
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}
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int main(int argc, char *argv[])
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{
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int fd, nbytes;
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int fd;
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ssize_t ret;
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struct simplefs_super_block sb;
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struct simplefs_inode root_inode;
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struct simplefs_inode welcomefile_inode;
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char welcomefile_name[] = "vanakkam";
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char welcomefile_body[] = "Love is God. God is Love. Anbe Murugan.\n";
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const uint64_t WELCOMEFILE_INODE_NUMBER = 2;
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const uint64_t WELCOMEFILE_DATABLOCK_NUMBER = 3;
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char *block_padding = NULL;
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struct simplefs_dir_record record;
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struct simplefs_inode welcome = {
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.mode = S_IFREG,
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.inode_no = WELCOMEFILE_INODE_NUMBER,
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.data_block_number = WELCOMEFILE_DATABLOCK_NUMBER,
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.file_size = sizeof(welcomefile_body),
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};
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struct simplefs_dir_record record = {
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.filename = "vanakkam",
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.inode_no = WELCOMEFILE_INODE_NUMBER,
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};
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if (argc != 2) {
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printf("Usage: mkfs-simplefs <device>\n");
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@ -37,126 +153,23 @@ int main(int argc, char *argv[])
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return -1;
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}
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/* Begin writing of Block 0 - Super Block */
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sb.version = 1;
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sb.magic = SIMPLEFS_MAGIC;
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sb.block_size = SIMPLEFS_DEFAULT_BLOCK_SIZE;
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ret = 1;
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do {
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if (write_superblock(fd))
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break;
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if (write_inode_store(fd))
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break;
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/* One inode for rootdirectory and another for a welcome file that we are going to create */
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sb.inodes_count = 2;
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/* FIXME: Free blocks management is not implemented yet */
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sb.free_blocks = ~0;
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sb.free_blocks &= ~(1 << WELCOMEFILE_DATABLOCK_NUMBER);
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ret = write(fd, (char *)&sb, sizeof(sb));
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if (ret != SIMPLEFS_DEFAULT_BLOCK_SIZE) {
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printf
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("bytes written [%d] are not equal to the default block size\n",
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(int)ret);
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ret = -1;
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goto exit;
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}
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printf("Super block written succesfully\n");
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/* End of writing of Block 0 - Super block */
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/* Begin writing of Block 1 - Inode Store */
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root_inode.mode = S_IFDIR;
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root_inode.inode_no = SIMPLEFS_ROOTDIR_INODE_NUMBER;
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root_inode.data_block_number = SIMPLEFS_ROOTDIR_DATABLOCK_NUMBER;
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root_inode.dir_children_count = 1;
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ret = write(fd, (char *)&root_inode, sizeof(root_inode));
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if (ret != sizeof(root_inode)) {
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printf
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("The inode store was not written properly. Retry your mkfs\n");
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ret = -1;
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goto exit;
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}
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printf("root directory inode written succesfully\n");
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welcomefile_inode.mode = S_IFREG;
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welcomefile_inode.inode_no = WELCOMEFILE_INODE_NUMBER;
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welcomefile_inode.data_block_number = WELCOMEFILE_DATABLOCK_NUMBER;
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welcomefile_inode.file_size = sizeof(welcomefile_body);
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ret = write(fd, (char *)&welcomefile_inode, sizeof(root_inode));
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if (ret != sizeof(root_inode)) {
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printf
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("The welcomefile inode was not written properly. Retry your mkfs\n");
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ret = -1;
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goto exit;
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}
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printf("welcomefile inode written succesfully\n");
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nbytes =
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SIMPLEFS_DEFAULT_BLOCK_SIZE - sizeof(root_inode) -
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sizeof(welcomefile_inode);
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block_padding = malloc(nbytes);
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ret = write(fd, block_padding, nbytes);
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if (ret != nbytes) {
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printf
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("The padding bytes are not written properly. Retry your mkfs\n");
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ret = -1;
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goto exit;
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}
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printf
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("inode store padding bytes (after the two inodes) written sucessfully\n");
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/* End of writing of Block 1 - inode Store */
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/* Begin writing of Block 2 - Root Directory datablocks */
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strcpy(record.filename, welcomefile_name);
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record.inode_no = WELCOMEFILE_INODE_NUMBER;
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nbytes = sizeof(record);
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ret = write(fd, (char *)&record, nbytes);
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if (ret != nbytes) {
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printf
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("Writing the rootdirectory datablock (name+inode_no pair for welcomefile) has failed\n");
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ret = -1;
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goto exit;
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}
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printf
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("root directory datablocks (name+inode_no pair for welcomefile) written succesfully\n");
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nbytes = SIMPLEFS_DEFAULT_BLOCK_SIZE - sizeof(record);
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block_padding = realloc(block_padding, nbytes);
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ret = write(fd, block_padding, nbytes);
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if (ret != nbytes) {
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printf
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("Writing the padding for rootdirectory children datablock has failed\n");
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ret = -1;
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goto exit;
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}
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printf
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("padding after the rootdirectory children written succesfully\n");
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/* End of writing of Block 2 - Root directory contents */
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/* Begin writing of Block 3 - Welcome file contents */
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nbytes = sizeof(welcomefile_body);
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ret = write(fd, welcomefile_body, nbytes);
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if (ret != nbytes) {
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printf("Writing welcomefile body has failed\n");
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ret = -1;
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goto exit;
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}
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printf("welcomefilebody has been written succesfully\n");
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/* End of writing of Block 3 - Welcome file contents */
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if (write_inode(fd, &welcome))
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break;
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if (write_dirent(fd, &record))
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break;
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if (write_block(fd, welcomefile_body, welcome.file_size))
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break;
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ret = 0;
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} while (0);
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exit:
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if (block_padding) {
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free(block_padding);
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}
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close(fd);
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return ret;
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}
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