ext4: fix races of writeback with punch hole and zero range

ext4: fix races of writeback with punch hole and zero range

Orabug: 23331012

When doing delayed allocation, update of on-disk inode size is postponed
until IO submission time. However hole punch or zero range fallocate
calls can end up discarding the tail page cache page and thus on-disk
inode size would never be properly updated.

Make sure the on-disk inode size is updated before truncating page
cache.

Signed-off-by: Jan Kara <jack@suse.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Mingming Cao <mingming.cao@oracle.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
(cherry picked from commit f2b132595b89d9236b386e1d6ed3fcf5e9edf4cb)

Signed-off-by: Dan Duval <dan.duval@oracle.com>