Hi Kent,

thanks for reply. i read the document in the code. just to make sure i
understand correctly, the stale key nodes are produced by invalidation
(replacement) of the buckets they reside on, right?
in another word, the stale key nodes might be the recently evict out data?

Thanks,
Sheng

On Mon, Jul 8, 2013 at 5:48 PM, Kent Overstreet [off-list ref] wrote:

On Mon, Jul 08, 2013 at 09:44:41AM -0400, sheng qiu wrote:

quoted

Hi Kent,

Thanks a lot for your reply.

Then i have a question about the bucket invalidation. when bcache
choose to replace a bucket, will the keys that reside on that bucket
still be in the btree? since you do not have information about which
keys reside on the bucket, how do you update the btree?

i can think out two ways, one is you periodically scan the btree nodes
and delete the stale nodes, the other way is when you get a cache hit
on stale nodes, then you delete it at that moment. How bcache does
this? Can you tell me the functions involve for these operations? i am
interested in this part of codes.

This is documented in the code - start here:
http://evilpiepirate.org/git/linux-bcache.git/tree/drivers/md/bcache/bcache.h?h=bcache-dev

-- 
Sheng Qiu
Texas A & M University
Room 332B Wisenbaker
email: herbert1984106-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
College Station, TX 77843-3259