On Fri, Mar 04, 2016 at 08:38:55AM -0500, Brian Foster wrote: > One thing I'm a bit suspicious about still is whether the error > propagation is racy. For example, consider we've created two chained > bios A and B, such that A is the parent and thus bio(io_remaining) for > each is A(2) and B(1). Suppose bio A happens to complete first with an > error. A->bi_error is set and bio_endio(A) is called, which IIUC > basically just does A(2)->A(1). If bio B completes successfully, > B->bi_error presumably remains set to 0 and bio_endio(B) is called. The > latter checks that B->bi_end_io == bio_chain_endio, propagates > B->bi_error to A->bi_error unconditionally and then walks up to the > parent bio to drop its reference and finally call A->bi_end_io(). > > Doesn't this mean that we can potentially lose errors in the chain? I > could easily still be missing something here... Yes, it looks like bio_chain_endio and bio_endio should be fixed to only set parent->bi_error if it's not already set. I'll send a patch. _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
