inode.c

LINUX 1.0 内核c源代码,是一份精简的linux内核源代码

		goal = inode->u.ext2_i.i_next_alloc_goal;
	if (!goal) {
		for (tmp = nr - 1; tmp >= 0; tmp--) {
			if (((unsigned long *) bh->b_data)[tmp]) {
				goal = ((unsigned long *)bh->b_data)[tmp];
				break;
			}
		}
		if (!goal)
			goal = bh->b_blocknr;
	}
	tmp = ext2_alloc_block (inode, goal);
	if (!tmp) {
		brelse (bh);
		return NULL;
	}
	result = getblk (bh->b_dev, tmp, blocksize);
	if (*p) {
		ext2_free_blocks (inode->i_sb, tmp, 1);
		brelse (result);
		goto repeat;
	}
	*p = tmp;
	bh->b_dirt = 1;
	if (IS_SYNC(inode)) {
		ll_rw_block (WRITE, 1, &bh);
		wait_on_buffer (bh);
	}
	inode->i_ctime = CURRENT_TIME;
	inode->i_blocks += blocks;
	inode->i_dirt = 1;
	inode->u.ext2_i.i_next_alloc_block = new_block;
	inode->u.ext2_i.i_next_alloc_goal = tmp;
	brelse (bh);
	return result;
}

struct buffer_head * ext2_getblk (struct inode * inode, long block,
				  int create, int * err)
{
	struct buffer_head * bh;
	unsigned long b;
	unsigned long addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);

	*err = -EIO;
	if (block < 0) {
		ext2_warning (inode->i_sb, "ext2_getblk", "block < 0");
		return NULL;
	}
	if (block > EXT2_NDIR_BLOCKS + addr_per_block  +
		    addr_per_block * addr_per_block +
		    addr_per_block * addr_per_block * addr_per_block) {
		ext2_warning (inode->i_sb, "ext2_getblk", "block > big");
		return NULL;
	}
	/*
	 * If this is a sequential block allocation, set the next_alloc_block
	 * to this block now so that all the indblock and data block
	 * allocations use the same goal zone
	 */

	ext2_debug ("block %lu, next %lu, goal %lu.\n", block, 
		    inode->u.ext2_i.i_next_alloc_block,
		    inode->u.ext2_i.i_next_alloc_goal);

	if (block == inode->u.ext2_i.i_next_alloc_block + 1) {
		inode->u.ext2_i.i_next_alloc_block++;
		inode->u.ext2_i.i_next_alloc_goal++;
	}

	*err = -ENOSPC;
	b = block;
	if (block < EXT2_NDIR_BLOCKS)
		return inode_getblk (inode, block, create, b, err);
	block -= EXT2_NDIR_BLOCKS;
	if (block < addr_per_block) {
		bh = inode_getblk (inode, EXT2_IND_BLOCK, create, b, err);
		return block_getblk (inode, bh, block, create,
				     inode->i_sb->s_blocksize, b, err);
	}
	block -= addr_per_block;
	if (block < addr_per_block * addr_per_block) {
		bh = inode_getblk (inode, EXT2_DIND_BLOCK, create, b, err);
		bh = block_getblk (inode, bh, block / addr_per_block, create,
				   inode->i_sb->s_blocksize, b, err);
		return block_getblk (inode, bh, block & (addr_per_block - 1),
				     create, inode->i_sb->s_blocksize, b, err);
	}
	block -= addr_per_block * addr_per_block;
	bh = inode_getblk (inode, EXT2_TIND_BLOCK, create, b, err);
	bh = block_getblk (inode, bh, block/(addr_per_block * addr_per_block),
			   create, inode->i_sb->s_blocksize, b, err);
	bh = block_getblk (inode, bh, (block/addr_per_block) & (addr_per_block - 1),
			   create, inode->i_sb->s_blocksize, b, err);
	return block_getblk (inode, bh, block & (addr_per_block - 1), create,
			     inode->i_sb->s_blocksize, b, err);
}

struct buffer_head * ext2_bread (struct inode * inode, int block, 
				 int create, int *err)
{
	struct buffer_head * bh;

	bh = ext2_getblk (inode, block, create, err);
	if (!bh || bh->b_uptodate)
		return bh;
	ll_rw_block (READ, 1, &bh);
	wait_on_buffer (bh);
	if (bh->b_uptodate)
		return bh;
	brelse (bh);
	*err = -EIO;
	return NULL;
}

void ext2_read_inode (struct inode * inode)
{
	struct buffer_head * bh;
	struct ext2_inode * raw_inode;
	unsigned long block_group;
	unsigned long group_desc;
	unsigned long desc;
	unsigned long block;
	struct ext2_group_desc * gdp;

	if ((inode->i_ino != EXT2_ROOT_INO && inode->i_ino != EXT2_ACL_IDX_INO &&
	     inode->i_ino != EXT2_ACL_DATA_INO && inode->i_ino < EXT2_FIRST_INO) ||
	    inode->i_ino > inode->i_sb->u.ext2_sb.s_es->s_inodes_count) {
		ext2_error (inode->i_sb, "ext2_read_inode",
			    "bad inode number: %lu", inode->i_ino);
		return;
	}
	block_group = (inode->i_ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
	if (block_group >= inode->i_sb->u.ext2_sb.s_groups_count)
		ext2_panic (inode->i_sb, "ext2_read_inode",
			    "group >= groups count");
	group_desc = block_group / EXT2_DESC_PER_BLOCK(inode->i_sb);
	desc = block_group % EXT2_DESC_PER_BLOCK(inode->i_sb);
	bh = inode->i_sb->u.ext2_sb.s_group_desc[group_desc];
	if (!bh)
		ext2_panic (inode->i_sb, "ext2_read_inode",
			    "Descriptor not loaded");
	gdp = (struct ext2_group_desc *) bh->b_data;
	block = gdp[desc].bg_inode_table +
		(((inode->i_ino - 1) % EXT2_INODES_PER_GROUP(inode->i_sb))
		 / EXT2_INODES_PER_BLOCK(inode->i_sb));
	if (!(bh = bread (inode->i_dev, block, inode->i_sb->s_blocksize)))
		ext2_panic (inode->i_sb, "ext2_read_inode",
			    "unable to read i-node block\n"
			    "inode=%lu, block=%lu", inode->i_ino, block);
	raw_inode = ((struct ext2_inode *) bh->b_data) +
		(inode->i_ino - 1) % EXT2_INODES_PER_BLOCK(inode->i_sb);
	inode->i_mode = raw_inode->i_mode;
	inode->i_uid = raw_inode->i_uid;
	inode->i_gid = raw_inode->i_gid;
	inode->i_nlink = raw_inode->i_links_count;
	inode->i_size = raw_inode->i_size;
	inode->i_atime = raw_inode->i_atime;
	inode->i_ctime = raw_inode->i_ctime;
	inode->i_mtime = raw_inode->i_mtime;
	inode->u.ext2_i.i_dtime = raw_inode->i_dtime;
	inode->i_blksize = inode->i_sb->s_blocksize;
	inode->i_blocks = raw_inode->i_blocks;
	inode->u.ext2_i.i_flags = raw_inode->i_flags;
	inode->u.ext2_i.i_faddr = raw_inode->i_faddr;
	inode->u.ext2_i.i_frag = raw_inode->i_frag;
	inode->u.ext2_i.i_fsize = raw_inode->i_fsize;
	inode->u.ext2_i.i_file_acl = raw_inode->i_file_acl;
	inode->u.ext2_i.i_dir_acl = raw_inode->i_dir_acl;
	inode->u.ext2_i.i_version = raw_inode->i_version;
	inode->u.ext2_i.i_block_group = block_group;
	inode->u.ext2_i.i_next_alloc_block = 0;
	inode->u.ext2_i.i_next_alloc_goal = 0;
	if (inode->u.ext2_i.i_prealloc_count)
		ext2_error (inode->i_sb, "ext2_read_inode",
			    "New inode has non-zero prealloc count!");
	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
		inode->i_rdev = raw_inode->i_block[0];
	else for (block = 0; block < EXT2_N_BLOCKS; block++)
		inode->u.ext2_i.i_data[block] = raw_inode->i_block[block];
	brelse (bh);
	inode->i_op = NULL;
	if (inode->i_ino == EXT2_ACL_IDX_INO ||
	    inode->i_ino == EXT2_ACL_DATA_INO)
		/* Nothing to do */ ;
	else if (S_ISREG(inode->i_mode))
		inode->i_op = &ext2_file_inode_operations;
	else if (S_ISDIR(inode->i_mode))
		inode->i_op = &ext2_dir_inode_operations;
	else if (S_ISLNK(inode->i_mode))
		inode->i_op = &ext2_symlink_inode_operations;
	else if (S_ISCHR(inode->i_mode))
		inode->i_op = &chrdev_inode_operations;
	else if (S_ISBLK(inode->i_mode))
		inode->i_op = &blkdev_inode_operations;
	else if (S_ISFIFO(inode->i_mode))
		init_fifo(inode);
	if (inode->u.ext2_i.i_flags & EXT2_SYNC_FL)
		inode->i_flags |= MS_SYNC;
}

static struct buffer_head * ext2_update_inode (struct inode * inode)
{
	struct buffer_head * bh;
	struct ext2_inode * raw_inode;
	unsigned long block_group;
	unsigned long group_desc;
	unsigned long desc;
	unsigned long block;
	struct ext2_group_desc * gdp;

	if ((inode->i_ino != EXT2_ROOT_INO && inode->i_ino < EXT2_FIRST_INO) ||
	    inode->i_ino > inode->i_sb->u.ext2_sb.s_es->s_inodes_count) {
		ext2_error (inode->i_sb, "ext2_write_inode",
			    "bad inode number: %lu", inode->i_ino);
		return 0;
	}
	block_group = (inode->i_ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
	if (block_group >= inode->i_sb->u.ext2_sb.s_groups_count)
		ext2_panic (inode->i_sb, "ext2_write_inode",
			    "group >= groups count");
	group_desc = block_group / EXT2_DESC_PER_BLOCK(inode->i_sb);
	desc = block_group % EXT2_DESC_PER_BLOCK(inode->i_sb);
	bh = inode->i_sb->u.ext2_sb.s_group_desc[group_desc];
	if (!bh)
		ext2_panic (inode->i_sb, "ext2_write_inode",
			    "Descriptor not loaded");
	gdp = (struct ext2_group_desc *) bh->b_data;
	block = gdp[desc].bg_inode_table +
		(((inode->i_ino - 1) % EXT2_INODES_PER_GROUP(inode->i_sb))
		 / EXT2_INODES_PER_BLOCK(inode->i_sb));
	if (!(bh = bread (inode->i_dev, block, inode->i_sb->s_blocksize)))
		ext2_panic (inode->i_sb, "ext2_write_inode",
			    "unable to read i-node block\n"
			    "inode=%lu, block=%lu", inode->i_ino, block);
	raw_inode = ((struct ext2_inode *)bh->b_data) +
		(inode->i_ino - 1) % EXT2_INODES_PER_BLOCK(inode->i_sb);
	raw_inode->i_mode = inode->i_mode;
	raw_inode->i_uid = inode->i_uid;
	raw_inode->i_gid = inode->i_gid;
	raw_inode->i_links_count = inode->i_nlink;
	raw_inode->i_size = inode->i_size;
	raw_inode->i_atime = inode->i_atime;
	raw_inode->i_ctime = inode->i_ctime;
	raw_inode->i_mtime = inode->i_mtime;
	raw_inode->i_blocks = inode->i_blocks;
	raw_inode->i_dtime = inode->u.ext2_i.i_dtime;
	raw_inode->i_flags = inode->u.ext2_i.i_flags;
	raw_inode->i_faddr = inode->u.ext2_i.i_faddr;
	raw_inode->i_frag = inode->u.ext2_i.i_frag;
	raw_inode->i_fsize = inode->u.ext2_i.i_fsize;
	raw_inode->i_file_acl = inode->u.ext2_i.i_file_acl;
	raw_inode->i_dir_acl = inode->u.ext2_i.i_dir_acl;
	raw_inode->i_version = inode->u.ext2_i.i_version;
	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
		raw_inode->i_block[0] = inode->i_rdev;
	else for (block = 0; block < EXT2_N_BLOCKS; block++)
		raw_inode->i_block[block] = inode->u.ext2_i.i_data[block];
	bh->b_dirt = 1;
	inode->i_dirt = 0;
	return bh;
}

void ext2_write_inode (struct inode * inode)
{
	struct buffer_head * bh;
	bh = ext2_update_inode (inode);
	brelse (bh);
}

int ext2_sync_inode (struct inode *inode)
{
	int err = 0;
	struct buffer_head *bh;

	bh = ext2_update_inode (inode);
	if (bh && bh->b_dirt)
	{
		ll_rw_block (WRITE, 1, &bh);
		wait_on_buffer (bh);
		if (bh->b_req && !bh->b_uptodate)
		{
			printk ("IO error syncing ext2 inode [%04x:%08lx]\n",
				inode->i_dev, inode->i_ino);
			err = -1;
		}
	}
	else if (!bh)
		err = -1;
	brelse (bh);
	return err;
}