ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
		 struct ext4_ext_path *path,
		 struct partial_cluster *partial,
		 ext4_lblk_t start, ext4_lblk_t end)
{
	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
	int err = 0, correct_index = 0;
	int depth = ext_depth(inode), credits, revoke_credits;
	struct ext4_extent_header *eh;
	ext4_lblk_t a, b;
	unsigned num;
	ext4_lblk_t ex_ee_block;
	unsigned short ex_ee_len;
	unsigned unwritten = 0;
	struct ext4_extent *ex;
	ext4_fsblk_t pblk;

	/* the header must be checked already in ext4_ext_remove_space() */
	ext_debug(inode, "truncate since %u in leaf to %u\n", start, end);
	if (!path[depth].p_hdr)
		path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
	eh = path[depth].p_hdr;
	if (unlikely(path[depth].p_hdr == NULL)) {
		EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
		return -EFSCORRUPTED;
	}
	/* find where to start removing */
	ex = path[depth].p_ext;
	if (!ex)
		ex = EXT_LAST_EXTENT(eh);

	ex_ee_block = le32_to_cpu(ex->ee_block);
	ex_ee_len = ext4_ext_get_actual_len(ex);

	trace_ext4_ext_rm_leaf(inode, start, ex, partial);

	while (ex >= EXT_FIRST_EXTENT(eh) &&
			ex_ee_block + ex_ee_len > start) {

		if (ext4_ext_is_unwritten(ex))
			unwritten = 1;
		else
			unwritten = 0;

		ext_debug(inode, "remove ext %u:[%d]%d\n", ex_ee_block,
			  unwritten, ex_ee_len);
		path[depth].p_ext = ex;

		a = ex_ee_block > start ? ex_ee_block : start;
		b = ex_ee_block+ex_ee_len - 1 < end ?
			ex_ee_block+ex_ee_len - 1 : end;

		ext_debug(inode, "  border %u:%u\n", a, b);

		/* If this extent is beyond the end of the hole, skip it */
		if (end < ex_ee_block) {
			/*
			 * We're going to skip this extent and move to another,
			 * so note that its first cluster is in use to avoid
			 * freeing it when removing blocks.  Eventually, the
			 * right edge of the truncated/punched region will
			 * be just to the left.
			 */
			if (sbi->s_cluster_ratio > 1) {
				pblk = ext4_ext_pblock(ex);
				partial->pclu = EXT4_B2C(sbi, pblk);
				partial->state = nofree;
			}
			ex--;
			ex_ee_block = le32_to_cpu(ex->ee_block);
			ex_ee_len = ext4_ext_get_actual_len(ex);
			continue;
		} else if (b != ex_ee_block + ex_ee_len - 1) {
			EXT4_ERROR_INODE(inode,
					 "can not handle truncate %u:%u "
					 "on extent %u:%u",
					 start, end, ex_ee_block,
					 ex_ee_block + ex_ee_len - 1);
			err = -EFSCORRUPTED;
			goto out;
		} else if (a != ex_ee_block) {
			/* remove tail of the extent */
			num = a - ex_ee_block;
		} else {
			/* remove whole extent: excellent! */
			num = 0;
		}
		/*
		 * 3 for leaf, sb, and inode plus 2 (bmap and group
		 * descriptor) for each block group; assume two block
		 * groups plus ex_ee_len/blocks_per_block_group for
		 * the worst case
		 */
		credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
		if (ex == EXT_FIRST_EXTENT(eh)) {
			correct_index = 1;
			credits += (ext_depth(inode)) + 1;
		}
		credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
		/*
		 * We may end up freeing some index blocks and data from the
		 * punched range. Note that partial clusters are accounted for
		 * by ext4_free_data_revoke_credits().
		 */
		revoke_credits =
			ext4_free_metadata_revoke_credits(inode->i_sb,
							  ext_depth(inode)) +
			ext4_free_data_revoke_credits(inode, b - a + 1);

		err = ext4_datasem_ensure_credits(handle, inode, credits,
						  credits, revoke_credits);
		if (err) {
			if (err > 0)
				err = -EAGAIN;
			goto out;
		}

		err = ext4_ext_get_access(handle, inode, path + depth);
		if (err)
			goto out;

		err = ext4_remove_blocks(handle, inode, ex, partial, a, b);
		if (err)
			goto out;

		if (num == 0)
			/* this extent is removed; mark slot entirely unused */
			ext4_ext_store_pblock(ex, 0);

		ex->ee_len = cpu_to_le16(num);
		/*
		 * Do not mark unwritten if all the blocks in the
		 * extent have been removed.
		 */
		if (unwritten && num)
			ext4_ext_mark_unwritten(ex);
		/*
		 * If the extent was completely released,
		 * we need to remove it from the leaf
		 */
		if (num == 0) {
			if (end != EXT_MAX_BLOCKS - 1) {
				/*
				 * For hole punching, we need to scoot all the
				 * extents up when an extent is removed so that
				 * we dont have blank extents in the middle
				 */
				memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
					sizeof(struct ext4_extent));

				/* Now get rid of the one at the end */
				memset(EXT_LAST_EXTENT(eh), 0,
					sizeof(struct ext4_extent));
			}
			le16_add_cpu(&eh->eh_entries, -1);
		}

		err = ext4_ext_dirty(handle, inode, path + depth);
		if (err)
			goto out;

		ext_debug(inode, "new extent: %u:%u:%llu\n", ex_ee_block, num,
				ext4_ext_pblock(ex));
		ex--;
		ex_ee_block = le32_to_cpu(ex->ee_block);
		ex_ee_len = ext4_ext_get_actual_len(ex);
	}

	if (correct_index && eh->eh_entries)
		err = ext4_ext_correct_indexes(handle, inode, path);

	/*
	 * If there's a partial cluster and at least one extent remains in
	 * the leaf, free the partial cluster if it isn't shared with the
	 * current extent.  If it is shared with the current extent
	 * we reset the partial cluster because we've reached the start of the
	 * truncated/punched region and we're done removing blocks.
	 */
	if (partial->state == tofree && ex >= EXT_FIRST_EXTENT(eh)) {
		pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
		if (partial->pclu != EXT4_B2C(sbi, pblk)) {
			int flags = get_default_free_blocks_flags(inode);

			if (ext4_is_pending(inode, partial->lblk))
				flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
			ext4_free_blocks(handle, inode, NULL,
					 EXT4_C2B(sbi, partial->pclu),
					 sbi->s_cluster_ratio, flags);
			if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
				ext4_rereserve_cluster(inode, partial->lblk);
		}
		partial->state = initial;
	}

	/* if this leaf is free, then we should
	 * remove it from index block above */
	if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
		err = ext4_ext_rm_idx(handle, inode, path, depth);

out:
	return err;
}