On Tue, Apr 15, 2014 at 06:06:00PM -0400, Brian Foster wrote: > On Wed, Apr 16, 2014 at 07:46:42AM +1000, Dave Chinner wrote: > > On Tue, Apr 15, 2014 at 03:40:00PM -0400, Brian Foster wrote: > > > Should we always expect an unchecked buffer to be read with an ops > > > vector before being written? Even if so, this might look cleaner if we > > > didn't encode the possibility of running a read verifier on a dirty > > > buffer. I presume that would always fail as the crc is updated in the > > > write verifier. > > > > It should fail, and that's a good thing because writing to an > > unchecked buffer would indicate that we didn't validate it properly > > in the first place. Hence I thought that doing it this way leaves > > a canary that traps other problem usage with unchecked buffers. > > > > Realistically, we shouldn't be writing unchecked buffers - prefetch > > doesn't touch buffers, it just does IO, and so someone else has to > > read the buffers before they can be dirtied. If it's read without an > > ops structure then modified and read again with an ops structure, > > we'll catch it... > > > > Ah, I see. That sounds good, but a small comment there with the > reasoning to allow a read verifier to run on a dirty buffer would be > nice. :) Ok, I'll add one. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
