void ext2_disk_mount() {
DC = malloc(sizeof(ext2_disk_cache_entry_t) * CACHEENTRIES);
SB = malloc(BLOCKSIZE);
ext2_disk_read_block(1, (uint8_t *)SB);
assert(SB->magic == EXT2_SUPER_MAGIC);
if (SB->inode_size == 0) {
SB->inode_size = 128;
}
BGDS = SB->blocks_count / SB->blocks_per_group;
ext2_disk_inodes_per_group = SB->inodes_count / BGDS;
// load the block group descriptors
BGD = malloc(BLOCKSIZE);
ext2_disk_read_block(2, (uint8_t *)BGD);
#if EXT2_DEBUG_BLOCK_DESCRIPTORS
char bg_buffer[BLOCKSIZE];
for (uint32_t i = 0; i < BGDS; ++i) {
kprintf("Block Group Descriptor #%d @ %d\n", i, 2 + i * SB->blocks_per_group);
kprintf("\tBlock Bitmap @ %d\n", BGD[i].block_bitmap); {
kprintf("\t\tExamining block bitmap at %d\n", BGD[i].block_bitmap);
ext2_disk_read_block(BGD[i].block_bitmap, (uint8_t *)bg_buffer);
uint32_t j = 0;
while (BLOCKBIT(j)) {
++j;
}
kprintf("\t\tFirst free block in group is %d\n", j + BGD[i].block_bitmap - 2);
}
kprintf("\tInode Bitmap @ %d\n", BGD[i].inode_bitmap); {
kprintf("\t\tExamining inode bitmap at %d\n", BGD[i].inode_bitmap);
ext2_disk_read_block(BGD[i].inode_bitmap, (uint8_t *)bg_buffer);
uint32_t j = 0;
while (BLOCKBIT(j)) {
++j;
}
kprintf("\t\tFirst free inode in group is %d\n", j + ext2_disk_inodes_per_group * i + 1);
}
kprintf("\tInode Table @ %d\n", BGD[i].inode_table);
kprintf("\tFree Blocks = %d\n", BGD[i].free_blocks_count);
kprintf("\tFree Inodes = %d\n", BGD[i].free_inodes_count);
}
#endif
ext2_inodetable_t *root_inode = ext2_disk_inode(2);
RN = (fs_node_t *)malloc(sizeof(fs_node_t));
assert(ext2_disk_node_root(root_inode, RN));
fs_root = RN;
LOG(INFO,"Mounted EXT2 disk, root VFS node is at 0x%x", RN);
}
/**
* Allocate memory for a block in an inode whose inode number is 'no'.
*/
void ext2_disk_inode_alloc_block(ext2_inodetable_t *inode, uint32_t no, uint32_t block) {
uint32_t block_no = 0, block_offset = 0, group = 0;
char *bg_buffer = malloc(BLOCKSIZE);
for (uint32_t i = 0; i < BGDS; ++i) {
if (BGD[i].free_blocks_count > 0) {
ext2_disk_read_block(BGD[i].block_bitmap, (uint8_t *)bg_buffer);
while (BLOCKBIT(block_offset))
++block_offset;
block_no = block_offset + SB->blocks_per_group * i + 1;
group = i;
break;
}
}
if (!block_no) {
kprintf("[kernel/ext2] No available blocks!\n");
free(bg_buffer);
return;
}
// Found a block (block_no), we need to mark it as in-use
uint8_t b = BLOCKBYTE(block_offset);
b |= SETBIT(block_offset);
BLOCKBYTE(block_offset) = b;
ext2_disk_write_block(BGD[group].block_bitmap, (uint8_t *)bg_buffer);
free(bg_buffer);
ext2_set_real_block(inode, block, block_no);
// Now update available blocks count
BGD[group].free_blocks_count -= 1;
ext2_disk_write_block(2, (uint8_t *)BGD);
inode->blocks++;
ext2_disk_write_inode(inode, no);
}
/**
* Allocate a new inode with parent as the parent directory node and name as the filename
* within that parent directory. Returns a pointer to a memory-copy of the node which
* the client can (and should) free.
* 'ftype' is file type, used when adding the entry to the parent dir. 1 for regular file,
* 2 for directory, etc... 'no' is the inode number of 'parent'.
* Upon return, the inode number of the newly allocated inode will be stored in 'inode_no'.
*
* This function assumes that parent directory 'parent' does not contain any entry with
* same name as 'name'. Caller shuold ensure this.
* Note that inode just created using this function has size of 0, which means no data
* blocks have been allocated to the inode.
*/
ext2_inodetable_t *ext2_disk_alloc_inode
(
ext2_inodetable_t *parent,
uint32_t no,
char *name,
uint16_t mode,
uint32_t *inode_no
) {
if ((parent->mode & EXT2_S_IFDIR) == 0 || name == NULL) {
kprintf("[kernel/ext2] No name or bad parent.\n");
return NULL;
}
ext2_inodetable_t *inode;
uint32_t node_no = 0, node_offset = 0, group = 0;
char *bg_buffer = malloc(BLOCKSIZE);
/* Locate a block with an available inode. Will probably be the first block group. */
for (uint32_t i = 0; i < BGDS; ++i) {
if (BGD[i].free_inodes_count > 0) {
#if EXT2_DEBUG_BLOCK_DESCRIPTORS
kprintf("Group %d has %d free inodes!\n", i, BGD[i].free_inodes_count);
#endif
ext2_disk_read_block(BGD[i].inode_bitmap, (uint8_t *)bg_buffer);
while (BLOCKBIT(node_offset))
++node_offset;
node_no = node_offset + ext2_disk_inodes_per_group * i + 1;
group = i;
break;
}
}
if (!node_no) {
kprintf("[kernel/ext2] Failure: No free inodes in block descriptors!\n");
free(bg_buffer);
return NULL;
}
/* Alright, we found an inode (node_no), we need to mark it as in-use... */
uint8_t b = BLOCKBYTE(node_offset);
#if EXT2_DEBUG_BLOCK_DESCRIPTORS
kprintf("Located an inode at #%d (%d), the byte for this block is currently set to %x\n", node_no, node_offset, (uint32_t)b);
#endif
b |= SETBIT(node_offset);
#if EXT2_DEBUG_BLOCK_DESCRIPTORS
kprintf("We would want to set it to %x\n", (uint32_t)b);
kprintf("Setting it in our temporary buffer...\n");
#endif
BLOCKBYTE(node_offset) = b;
#if EXT2_DEBUG_BLOCK_DESCRIPTORS
kprintf("\nWriting back out.\n");
#endif
ext2_disk_write_block(BGD[group].inode_bitmap, (uint8_t *)bg_buffer);
free(bg_buffer);
#if EXT2_DEBUG_BLOCK_DESCRIPTORS
kprintf("Okay, now we need to update the available inodes count...\n");
kprintf("it is %d, it should be %d\n", BGD[group].free_inodes_count, BGD[group].free_inodes_count - 1);
kprintf("\n");
kprintf("%d\n", BGD[group].free_inodes_count);
#endif
BGD[group].free_inodes_count -= 1;
#if EXT2_DEBUG_BLOCK_DESCRIPTORS
kprintf("%d\n", BGD[group].free_inodes_count);
kprintf("\nOkay, writing the block descriptors back to disk.\n");
#endif
ext2_disk_write_block(2, (uint8_t *)BGD);
#if EXT2_DEBUG_BLOCK_DESCRIPTORS
kprintf("Alright, we have an inode (%d), time to write it out to disk and make the file in the directory.\n", node_no);
#endif
// Get the inode struct from the disk and init it
inode = ext2_disk_inode(node_no);
inode->size = 0;
inode->blocks = 0;
inode->mode = mode;
ext2_disk_write_inode(inode, node_no);
*inode_no = node_no;
// Create an entry in the parent directory
uint8_t ftype = mode_to_filetype(mode);
kprintf("[kernel/ext2] Allocated inode, inserting directory entry [%d]...\n", node_no);
insertdir_ext2_disk(parent, no, node_no, name, ftype);
return inode;
}
void ext2_disk_mount(uint32_t offset_sector, uint32_t max_sector) {
debug_print(NOTICE, "Mounting EXT2 partition between sectors [%d:%d].", offset_sector, max_sector);
ext2_offset = offset_sector;
BLOCKSIZE = 1024;
SB = malloc(BLOCKSIZE);
ext2_disk_read_block(1, (uint8_t *)SB);
assert(SB->magic == EXT2_SUPER_MAGIC);
if (SB->inode_size == 0) {
SB->inode_size = 128;
}
BLOCKSIZE = 1024 << SB->log_block_size;
if (BLOCKSIZE > 2048) {
CACHEENTRIES /= 4;
}
PTRS_PER_BLOCK = BLOCKSIZE / 4;
debug_print(NOTICE, "Log block size = %d -> %d", SB->log_block_size, BLOCKSIZE);
BGDS = SB->blocks_count / SB->blocks_per_group;
if (SB->blocks_per_group * BGDS < SB->blocks_count) {
BGDS += 1;
}
ext2_disk_inodes_per_group = SB->inodes_count / BGDS;
debug_print(NOTICE, "Allocating cache...");
DC = malloc(sizeof(ext2_disk_cache_entry_t) * CACHEENTRIES);
for (uint32_t i = 0; i < CACHEENTRIES; ++i) {
DC[i].block = malloc(BLOCKSIZE);
if (i % 128 == 0) {
debug_print(INFO, "Allocated cache block #%d", i+1);
}
}
debug_print(NOTICE, "Allocated cache.");
// load the block group descriptors
int bgd_block_span = sizeof(ext2_bgdescriptor_t) * BGDS / BLOCKSIZE + 1;
BGD = malloc(BLOCKSIZE * bgd_block_span);
debug_print(INFO, "bgd_block_span = %d", bgd_block_span);
int bgd_offset = 2;
if (BLOCKSIZE > 1024) {
bgd_offset = 1;
}
for (int i = 0; i < bgd_block_span; ++i) {
ext2_disk_read_block(bgd_offset + i, (uint8_t *)((uint32_t)BGD + BLOCKSIZE * i));
}
#if EXT2_DEBUG_BLOCK_DESCRIPTORS
char * bg_buffer = malloc(BLOCKSIZE * sizeof(char));
for (uint32_t i = 0; i < BGDS; ++i) {
debug_print(INFO, "Block Group Descriptor #%d @ %d", i, bgd_offset + i * SB->blocks_per_group);
debug_print(INFO, "\tBlock Bitmap @ %d", BGD[i].block_bitmap); {
debug_print(INFO, "\t\tExamining block bitmap at %d", BGD[i].block_bitmap);
ext2_disk_read_block(BGD[i].block_bitmap, (uint8_t *)bg_buffer);
uint32_t j = 0;
while (BLOCKBIT(j)) {
++j;
}
debug_print(INFO, "\t\tFirst free block in group is %d", j + BGD[i].block_bitmap - 2);
}
debug_print(INFO, "\tInode Bitmap @ %d", BGD[i].inode_bitmap); {
debug_print(INFO, "\t\tExamining inode bitmap at %d", BGD[i].inode_bitmap);
ext2_disk_read_block(BGD[i].inode_bitmap, (uint8_t *)bg_buffer);
uint32_t j = 0;
while (BLOCKBIT(j)) {
++j;
}
debug_print(INFO, "\t\tFirst free inode in group is %d", j + ext2_disk_inodes_per_group * i + 1);
}
debug_print(INFO, "\tInode Table @ %d", BGD[i].inode_table);
debug_print(INFO, "\tFree Blocks = %d", BGD[i].free_blocks_count);
debug_print(INFO, "\tFree Inodes = %d", BGD[i].free_inodes_count);
}
free(bg_buffer);
#endif
ext2_inodetable_t *root_inode = ext2_disk_inode(2);
RN = (fs_node_t *)malloc(sizeof(fs_node_t));
if (!ext2_disk_node_root(root_inode, RN)) {
debug_print(NOTICE, "Oh dear...");
}
debug_print(NOTICE, "Root file system is ready.");
fs_root = RN;
debug_print(NOTICE, "Mounted EXT2 disk, root VFS node is at 0x%x", RN);
}