LU-10188 osd-zfs: handle non 4K aligned block size

LU-10188 osd-zfs: handle non 4K aligned block size

After restored from server side file level backup, the files
created via ZPL may use non 4K-bytes aligned block size. When
the device is mounted as Lustre, the zfs-osd will adjust the
client visible OST-objects' block size as at least 4K-bytes
aligned. For the objects that cannot be reset the block size,
the OSD logic needs to handle the non aligned case properly.
Otherwise, Lustre I/O handler may cause osd-zfs or ZFS panic
when osd_bufs_get_read().

Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: Ic07aeec3fc774508cedd6d24cca54b76171d143b
Reviewed-on: https://review.whamcloud.com/29241
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>