3.16.40-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Kashyap Desai <[email protected]> commit 1e793f6fc0db920400574211c48f9157a37e3945 upstream. Commit 02b01e010afe ("megaraid_sas: return sync cache call with success") modified the driver to successfully complete SYNCHRONIZE_CACHE commands without passing them to the controller. Disk drive caches are only explicitly managed by controller firmware when operating in RAID mode. So this commit effectively disabled writeback cache flushing for any drives used in JBOD mode, leading to data integrity failures. [mkp: clarified patch description] Fixes: 02b01e010afeeb49328d35650d70721d2ca3fd59 Signed-off-by: Kashyap Desai <[email protected]> Signed-off-by: Sumit Saxena <[email protected]> Reviewed-by: Tomas Henzl <[email protected]> Reviewed-by: Hannes Reinecke <[email protected]> Reviewed-by: Ewan D. Milne <[email protected]> Signed-off-by: Martin K. Petersen <[email protected]> Signed-off-by: Ben Hutchings <[email protected]> --- drivers/scsi/megaraid/megaraid_sas_base.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) --- a/drivers/scsi/megaraid/megaraid_sas_base.c +++ b/drivers/scsi/megaraid/megaraid_sas_base.c @@ -1586,16 +1586,13 @@ megasas_queue_command_lck(struct scsi_cm goto out_done; } - switch (scmd->cmnd[0]) { - case SYNCHRONIZE_CACHE: - /* - * FW takes care of flush cache on its own - * No need to send it down - */ + /* + * FW takes care of flush cache on its own for Virtual Disk. + * No need to send it down for VD. For JBOD send SYNCHRONIZE_CACHE to FW. + */ + if ((scmd->cmnd[0] == SYNCHRONIZE_CACHE) && MEGASAS_IS_LOGICAL(scmd)) { scmd->result = DID_OK << 16; goto out_done; - default: - break; } if (instance->instancet->build_and_issue_cmd(instance, scmd)) {
