Instead of it, just do not verify checksums of currently mutated objects.
When clean data modification during flush runs in parallel to a read request,
that request may read a mix of old and new data. It may even read a mix of
multiple flushed versions if it lasts too long... And attempts to verify it
using temporary copies of metadata make the algorithm too complex and creepy.
Fixes two bugs found during HDD testing :-)
1) OSD crashed with "BUG: Attempt to overwrite used offset of the journal" during
`fio -bs=900k -iodepth=128` test with 16 MB journal
2) OSD stalled during `fio -bs=512k -iodepth=128` test with 64 MB journal
Vitaliy Filippov