From a12c768df372747ebe0551fbc386b701f02c2b0b Mon Sep 17 00:00:00 2001 From: David Jeffery Date: Mon, 16 Sep 2019 13:15:14 -0400 Subject: md: improve handling of bio with REQ_PREFLUSH in md_flush_request() commit 775d78319f1ceb32be8eb3b1202ccdc60e9cb7f1 upstream. If pers->make_request fails in md_flush_request(), the bio is lost. To fix this, pass back a bool to indicate if the original make_request call should continue to handle the I/O and instead of assuming the flush logic will push it to completion. Convert md_flush_request to return a bool and no longer calls the raid driver's make_request function. If the return is true, then the md flush logic has or will complete the bio and the md make_request call is done. If false, then the md make_request function needs to keep processing like it is a normal bio. Let the original call to md_handle_request handle any need to retry sending the bio to the raid driver's make_request function should it be needed. Also mark md_flush_request and the make_request function pointer as __must_check to issue warnings should these critical return values be ignored. Fixes: 2bc13b83e629 ("md: batch flush requests.") Cc: stable@vger.kernel.org # # v4.19+ Cc: NeilBrown Signed-off-by: David Jeffery Reviewed-by: Xiao Ni Signed-off-by: Song Liu Signed-off-by: Greg Kroah-Hartman --- drivers/md/raid10.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'drivers/md/raid10.c') diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 4cf3d8ad0b4a..02c5e390f89f 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -1562,10 +1562,9 @@ static bool raid10_make_request(struct mddev *mddev, struct bio *bio) int chunk_sects = chunk_mask + 1; int sectors = bio_sectors(bio); - if (unlikely(bio->bi_opf & REQ_PREFLUSH)) { - md_flush_request(mddev, bio); + if (unlikely(bio->bi_opf & REQ_PREFLUSH) + && md_flush_request(mddev, bio)) return true; - } if (!md_write_start(mddev, bio)) return false; -- cgit v1.2.3