EX-8369 ldiskfs: fix dense writes

EX-8369 ldiskfs: fix dense writes

don't mix "dense" and regular writes as regular are bound
to logical offsets.

Fixes: f36eda6a1e ("LU-10026 osd-ldiskfs: use preallocation for dense writes")
Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Change-Id: I9f6b2c600f2132dcad23726f2fb3848ab02cc117
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/52888
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>