On Mon, 2008-01-07 at 15:05 +0100, Hannes Reinecke wrote:
But the assumption your code makes is that if REQ_FAILFAST is set then
it's a dm request ... and that's not true. The code in question
negatively impacts other users of REQ_FAILFAST. For every user other
than dm, the right thing to do is to wait out the block.
If it's a either/or choice between the two that's showing our current
approach to multi-path is broken.
But my point is that if a driver goes blocked, those commands will be
forced to wait the blocked timeout anyway, so your proposed patch does
nothing to improve the case for dm anyway ... you only avoid commands
stuck when a device goes blocked if by chance its request queue was