From 6f41469c627fe118121dfce2a8134ad24da3df28 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sun, 19 Apr 2009 07:00:41 +0900 Subject: [PATCH] block: clear req->errors on bio completion only for fs requests Impact: subtle behavior change For fs requests, rq is only carrier of bios and rq error status as a whole doesn't mean much. This is the reason why rq->errors is being cleared on each partial completion of a request as on each partial completion the error status is transferred to the respective bios. For pc requests, rq->errors is used to carry error status to the issuer and thus __end_that_request_first() doesn't clear it on such cases. The condition was fine till now as only fs and pc requests have used bio and thus the bio completion path. However, future changes will unify data accesses to bio and all non fs users care about rq error status. Clear rq->errors on bio completion only for fs requests. In general, the implicit clearing is a bit too subtle especially as the meaning of rq->errors is completely dependent on low level drivers. Unifying / cleaning up rq->errors usage and letting llds manage it would be better. TODO comment added. Signed-off-by: Tejun Heo Acked-by: Jens Axboe --- block/blk-core.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 07ab75403e1a..cce7a88dc612 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1739,10 +1739,14 @@ static int __end_that_request_first(struct request *req, int error, trace_block_rq_complete(req->q, req); /* - * for a REQ_TYPE_BLOCK_PC request, we want to carry any eventual - * sense key with us all the way through + * For fs requests, rq is just carrier of independent bio's + * and each partial completion should be handled separately. + * Reset per-request error on each partial completion. + * + * TODO: tj: This is too subtle. It would be better to let + * low level drivers do what they see fit. */ - if (!blk_pc_request(req)) + if (blk_fs_request(req)) req->errors = 0; if (error && (blk_fs_request(req) && !(req->cmd_flags & REQ_QUIET))) {