From 666eed46769d929c3e13636134ecfc67d75ef548 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Thu, 30 Mar 2023 15:09:29 -0400 Subject: [PATCH] dm: fix __send_duplicate_bios() to always allow for splitting IO Commit 7dd76d1feec70 ("dm: improve bio splitting and associated IO accounting") only called setup_split_accounting() from __send_duplicate_bios() if a single bio were being issued. But the case where duplicate bios are issued must call it too. Otherwise the bio won't be split and resubmitted (via recursion through block core back to DM) to submit the later portions of a bio (which may map to an entirely different target). For example, when discarding an entire DM striped device with the following DM table: vg-lvol0: 0 159744 striped 2 128 7:0 2048 7:1 2048 vg-lvol0: 159744 45056 striped 2 128 7:2 2048 7:3 2048 Before (broken, discards the first striped target's devices twice): device-mapper: striped: target_stripe=0, bdev=7:0, start=2048 len=79872 device-mapper: striped: target_stripe=1, bdev=7:1, start=2048 len=79872 device-mapper: striped: target_stripe=0, bdev=7:0, start=2049 len=22528 device-mapper: striped: target_stripe=1, bdev=7:1, start=2048 len=22528 After (works as expected): device-mapper: striped: target_stripe=0, bdev=7:0, start=2048 len=79872 device-mapper: striped: target_stripe=1, bdev=7:1, start=2048 len=79872 device-mapper: striped: target_stripe=0, bdev=7:2, start=2048 len=22528 device-mapper: striped: target_stripe=1, bdev=7:3, start=2048 len=22528 Fixes: 7dd76d1feec70 ("dm: improve bio splitting and associated IO accounting") Cc: stable@vger.kernel.org Reported-by: Orange Kao Signed-off-by: Mike Snitzer --- drivers/md/dm.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/md/dm.c b/drivers/md/dm.c index e67a275..dfde008 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1514,6 +1514,8 @@ static int __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti, ret = 1; break; default: + if (len) + setup_split_accounting(ci, *len); /* dm_accept_partial_bio() is not supported with shared tio->len_ptr */ alloc_multiple_bios(&blist, ci, ti, num_bios, len); while ((clone = bio_list_pop(&blist))) { -- 2.7.4