Import backup from 2004-12-29

Makefile

@@ -59,7 +59,7 @@ install_img:
 
 initrd:
 	dd if=/dev/zero of=$(INITRD) bs=1024 count=$(INITRD_SIZE)
-	mke2fs -Fv -m0 -r0 $(INITRD)
+	mke2fs -Fv -m0 -r0 -i1024 $(INITRD)
 	-mkdir $(INITRD_MOUNT)
 	mount -t ext2 -o loop $(INITRD) $(INITRD_MOUNT)
 	mkdir $(INITRD_MOUNT)/txt

kernel/fs/ext2.c

@@ -109,9 +109,69 @@ u32_t	ext2_get_inode_number(vfs_mount_t *mount, char *file)
 	return inode_number;
 }
 
+// DEBUG
+void	ext2_dump_root(vfs_mount_t *mount)
+{
+	ext2_open_dir_t *root_dir = ext2_open_dir(mount, 2);
+	ext2_dir_entry_t dentry;
+	while (!ext2_dir_read_entry(mount, root_dir, &dentry))
+	{
+		kprintf("Directory Entry: inode %d, length %d, name_length %d, file_type 0x%x, name '%s'\n",
+			dentry.inode, dentry.length, dentry.name_length, dentry.file_type, dentry.name);
+	}
+	ext2_close_dir(mount, root_dir);
+}
+
+// open a directory by inode number for reading
+ext2_open_dir_t *ext2_open_dir(vfs_mount_t *mount, u32_t inode_number)
+{
+	ext2_open_dir_t *open_dir = New(ext2_open_dir_t);
+	ext2_open_inode_t *open_inode = ext2_open_inode(mount, inode_number);
+	if (!open_inode)
+	{
+		kfree(open_dir);
+		return NULL;
+	}
+	open_dir->open_inode = open_inode;
+	open_dir->position = 0;
+	return open_dir;
+}
+
+int	ext2_dir_read_entry(vfs_mount_t *mount, ext2_open_dir_t *open_dir, ext2_dir_entry_t *dentry)
+{
+	ext2_super_block_t *super = mount->super;
+	if (open_dir->position >= open_dir->open_inode->inode.i_size)
+		return -1;		// EOF
+	u32_t dir_block = open_dir->position >> (10 + super->s_log_block_size);
+	char *block = kmalloc(2048 << super->s_log_block_size);
+	ext2_inode_seek(mount, open_dir->open_inode, dir_block);
+	if (ext2_read_inode_block(mount, open_dir->open_inode, block))
+		ext2_read_inode_block(mount, open_dir->open_inode, block + (1024 << super->s_log_block_size));
+	ext2_dir_entry_t *dir_entry = (ext2_dir_entry_t *)(block + open_dir->position % (1024 << super->s_log_block_size));
+	if (!dir_entry->inode)
+	{
+		kfree(block);
+		return -2;		// EOF
+	}
+	
+	memcpy(dentry, dir_entry, min(dir_entry->length, sizeof(ext2_dir_entry_t)));
+	open_dir->position += dir_entry->length;
+	kfree(block);
+	return 0;
+}
+
+int	ext2_close_dir(vfs_mount_t *mount, ext2_open_dir_t *open_dir)
+{
+	ext2_close_inode(mount, open_dir->open_inode);
+	kfree(open_dir);
+	return 0;
+}
+
 // open an inode for reading
 ext2_open_inode_t *ext2_open_inode(vfs_mount_t *mount, u32_t inode_number)
 {
+	if (ext2_inode_status(mount, inode_number) != 1)
+		return NULL;
 	ext2_inode_t inode = ext2_get_inode(mount, inode_number);
 	ext2_open_inode_t *open_inode = New(ext2_open_inode_t);
 	open_inode->inode = inode;
@@ -122,9 +182,54 @@ ext2_open_inode_t *ext2_open_inode(vfs_mount_t *mount, u32_t inode_number)
 	return open_inode;
 }
 
-// seek to a certain block of an open inode
+// check the status of an inode
-int	ext2_inode_seek(ext2_open_inode_t *open_inode, u32_t block_number)
+// -1: invalid inode number
+// 0: free inode
+// 1: allocated inode
+int	ext2_inode_status(vfs_mount_t *mount, u32_t inode_number)
 {
+	ext2_super_block_t *super = mount->super;
+	if (inode_number < 1 || inode_number > super->s_inodes_count)	// inode number invalid
+		return -1;
+	inode_number--;				// turn inode_number into a 0-based index
+	u32_t group = inode_number / super->s_inodes_per_group;
+	u32_t index = inode_number % super->s_inodes_per_group;
+	u32_t inode_bitmap_block = ext2_get_group_desc(mount, group).bg_inode_bitmap + (index >> (13 + super->s_log_block_size));
+	u32_t bitmap_index = index % (8192 << super->s_log_block_size);
+	u8_t *inode_bitmap = kmalloc(1024 << super->s_log_block_size);
+	block_read(mount->major, mount->minor,
+		ext2_FSToDiskBlock(inode_bitmap_block, super), 2 << super->s_log_block_size, inode_bitmap);
+	int inode_status = (inode_bitmap[bitmap_index >> 3] >> (bitmap_index & 0x7)) & 1;
+	kfree(inode_bitmap);
+	return inode_status;
+}
+
+// check the status of a block
+// -1: invalid block number
+// 0: free block
+// 1: allocated block
+int	ext2_block_status(vfs_mount_t *mount, u32_t block_number)
+{
+	ext2_super_block_t *super = mount->super;
+	if (block_number < super->s_first_data_block || block_number > super->s_blocks_count)	// block number invalid
+		return -1;
+	block_number -= super->s_first_data_block;
+	u32_t group = block_number / super->s_blocks_per_group;
+	u32_t index = block_number % super->s_blocks_per_group;
+	u32_t block_bitmap_block = ext2_get_group_desc(mount, group).bg_block_bitmap + (index >> (13 + super->s_log_block_size));
+	u32_t bitmap_index = index % (8192 << super->s_log_block_size);
+	u8_t *block_bitmap = kmalloc(1024 << super->s_log_block_size);
+	block_read(mount->major, mount->minor,
+		ext2_FSToDiskBlock(block_bitmap_block, super), 2 << super->s_log_block_size, block_bitmap);
+	int block_status = (block_bitmap[bitmap_index >> 3] >> (bitmap_index & 0x7)) & 1;
+	kfree(block_bitmap);
+	return block_status;
+}
+
+// seek to a certain block of an open inode
+int	ext2_inode_seek(vfs_mount_t *mount, ext2_open_inode_t *open_inode, u32_t block_number)
+{
+	ext2_super_block_t *super = mount->super;
 	if (open_inode->inode.i_size <= (block_number << (10 + super->s_log_block_size)))
 		return -1;	// at or past EOF
 	open_inode->block = block_number;

kernel/fs/ext2.h

@@ -146,6 +146,12 @@ typedef struct
 	u32_t	block_pointers_start;
 } ext2_open_inode_t;
 
+typedef struct
+{
+	ext2_open_inode_t	*open_inode;
+	u32_t	position;
+} ext2_open_dir_t;
+
 
 static inline u32_t	ext2_diskToFSBlock(u32_t block, ext2_super_block_t *super)
 {
@@ -172,7 +178,15 @@ int	ext2_close_inode(vfs_mount_t *mount, ext2_open_inode_t *open_inode);
 int	ext2_read_inode_block(vfs_mount_t *mount, ext2_open_inode_t *open_inode, void *block);
 u32_t	ext2_block_number(vfs_mount_t *mount, ext2_open_inode_t *open_inode);
 u32_t	ext2_get_inode_number(vfs_mount_t *mount, char *file);
-int	ext2_inode_seek(ext2_open_inode_t *open_inode, u32_t block_number);
+int	ext2_inode_seek(vfs_mount_t *mount, ext2_open_inode_t *open_inode, u32_t block_number);
+int	ext2_inode_status(vfs_mount_t *mount, u32_t inode_number);
+int	ext2_block_status(vfs_mount_t *mount, u32_t block_number);
+
+ext2_open_dir_t *ext2_open_dir(vfs_mount_t *mount, u32_t inode_number);
+int	ext2_dir_read_entry(vfs_mount_t *mount, ext2_open_dir_t *open_dir, ext2_dir_entry_t *dentry);
+int	ext2_close_dir(vfs_mount_t *mount, ext2_open_dir_t *open_dir);
+
+void	ext2_dump_root(vfs_mount_t *mount);
 
 #endif
 

kernel/fs/vfs.c

@@ -63,6 +63,9 @@ int	vfs_mount(major_t maj, minor_t min, int fsType, char *mountPoint)
 		kfree(mnt);
 		return -4;				// could not add mount
 	}
+	// DEBUG
+	ext2_dump_root(mnt);
+
 	return 0;
 }