Function ext4_ext_remove_space

Ext4Fsd/ext4/ext4_extents.c:2173–2281

}

int ext4_ext_remove_space(void *icb, struct inode *inode, unsigned long start)
{
	struct super_block *sb = inode->i_sb;
	int depth = ext_depth(inode);
	struct ext4_ext_path *path;
	handle_t *handle = NULL;
	int i = 0, err = 0;

	/* probably first extent we're gonna free will be last in block */
	/*handle = ext4_journal_start(inode, depth + 1);*/
	/*if (IS_ERR(icb, handle))*/
	/*return PTR_ERR(icb, handle);*/

	/*
	 * we start scanning from right side freeing all the blocks
	 * after i_size and walking into the deep
	 */
	path = kmalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_KERNEL);
	if (path == NULL) {
		ext4_journal_stop(icb, handle);
		return -ENOMEM;
	}
	memset(path, 0, sizeof(struct ext4_ext_path) * (depth + 1));
	path[0].p_hdr = ext_inode_hdr(inode);
	if (ext4_ext_check_inode(inode)) {
		err = -EIO;
		goto out;
	}
	path[0].p_depth = depth;

	while (i >= 0 && err == 0) {
		if (i == depth) {
			/* this is leaf block */
			err = ext4_ext_rm_leaf(icb, handle, inode, path, start);
			/* root level have p_bh == NULL, extents_brelse() eats this */
			extents_brelse(path[i].p_bh);
			path[i].p_bh = NULL;
			i--;
			continue;
		}

		/* this is index block */
		if (!path[i].p_hdr) {
			path[i].p_hdr = ext_block_hdr(path[i].p_bh);
		}

		if (!path[i].p_idx) {
			/* this level hasn't touched yet */
			path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
			path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
		} else {
			/* we've already was here, see at next index */
			path[i].p_idx--;
		}

		if (ext4_ext_more_to_rm(path + i)) {
			struct buffer_head *bh;
			/* go to the next level */