Hi Boaz,
The OSD protocol has the concept of caching and that the FUA (force
unit access) bit can be used to tell the server to commit a write to
stable storage, much like NFS' stable_how4. the object layout driver
does not switch on the server caching logic and does not implement
commit_pagelist method and its satellites. instead, it assumes write
is always to stable storage.
the pNFS client communicates stable_how4 (along with other infomation)
to the layout drivers via the 'how' argument of the write_pagelist
method. the object layout driver currently uses the 'how' argument to
decide whether or not to wait for the OSD requests to end or use a
callback, but translation of stable_how4 via 'how' to FUA bit is
missing.
--
Idan Kedar
Tonian