Re: end to end error recovery musings

["H. Peter Anvin" <hpa@zytor.com>]

Ric Wheeler wrote:
> 
> We still have the following challenges:
> 
>    (1) read-ahead often means that we will  retry every bad sector at 
> least twice from the file system level. The first time, the fs read 
> ahead request triggers a speculative read that includes the bad sector 
> (triggering the error handling mechanisms) right before the real 
> application triggers a read does the same thing.  Not sure what the 
> answer is here since read-ahead is obviously a huge win in the normal case.
> 

Probably the only sane thing to do is to remember the bad sectors and 
avoid attempting reading them; that would mean marking "automatic" 
versus "explicitly requested" requests to determine whether or not to 
filter them against a list of discovered bad blocks.

	-hpa