ext4: make ext4_da_reserve_space() reserve multi-clusters

Add 'nr_resv' parameter to ext4_da_reserve_space(), which indicates the
number of clusters wants to reserve, make it reserve multiple clusters
at a time.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20240517124005.347221-8-yi.zhang@huaweicloud.com


Signed-off-by: Theodore Ts'o <tytso@mit.edu>