Flush I/O should be forwarded to core and cache device. In case of core
this is simple - just mirror the I/O from the top volume. Since
cache data is owned by OCF it makes sense to send a simple flush I/O
with 0 address and size.
Current implementation attempts to use cache data I/O interface
(ocf_submit_cache_reqs function) instead of submitting empty flush to
the underlying cache device. This function is designed to read/write
from mapped cachelines while there is no traversation/mapping
performed on flush I/O.
If request map allocation succeeds, this results in sending I/O to
addres 0 with size and flags inherited from the top adapter I/O.
This doesn't make any sense, and can even result in invalid I/O if the
size is greater than cache device size.
Even worse, if flush request map allocation fails (which happens
always in case of large flush requests) then the erroneous call to
ocf_submit_cache_reqs results in NULL pointer dereference.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
When single request to cache was issued, stats updating function was called with
0 bytes as value to update. In case of many request issued to cache, stats were
updated only in case of error.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
Refactoring ocf_submit_cache_reqs to make it clear that
req->map is accessed at index derived from offset argument,
not necesarily starting at 0.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
Write-only cache mode is similar to writeback, however read
operations do not promote data to cache. Reads are mostly serviced
by the core device, only dirty sectors are fetched from the cache.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
This simplifies cases when we want to call completion callback
and immediately return from void-returning function, by allowing
to explicitly express programmers intent. That way we can avoid
cases when return statement is missing by mistake (this patch
fixes at least one bug related to this).
Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
NOTE: This is still not the real asynchronism. Metadata interfaces
are still not fully asynchronous.
Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
Propagate id of ocf_queue where it is possible
This resolves the issue of
bottom adapter always getting an ocf_io with io_queue = 0,
no matter from which queue function to bottom adapter was called
Signed-off-by: Vitaliy Mysak <vitaliy.mysak@intel.com>
