On 2/18/25 11:26 PM, Shinichiro Kawasaki wrote:
CC+: Alan, On Feb 13, 2025 / 08:18, Jens Axboe wrote:The conditions for whether or not a request is allowed adding to a completion batch are a bit hard to read, and they also have a few issues. One is that ioerror may indeed be a random value on passthrough, and it's being checked unconditionally of whether or not the given request is a passthrough request or not. Rewrite the conditions to be separate for easier reading, and only check ioerror for non-passthrough requests. This fixes an issue with bio unmapping on passthrough, where it fails getting added to a batch. This both leads to suboptimal performance, and may trigger a potential schedule-under-atomic condition for polled passthrough IO. Fixes: f794f3351f26 ("block: add support for blk_mq_end_request_batch()") Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>I observed the blktests test case nvme/039 failure with v6.14-rc3 kernel. I bisected and found that this patch in the v6.14-rc3 is the trigger. The test run output is as follows: nvme/039 => nvme0n1 (test error logging) [failed] runtime 5.378s ... 5.354s --- tests/nvme/039.out 2024-09-20 11:20:26.405380875 +0900 +++ /home/shin/Blktests/blktests/results/nvme0n1/nvme/039.out.bad 2025-02-19 16:13:05.061387179 +0900 @@ -1,7 +1,3 @@ Running nvme/039 - Read(0x2) @ LBA 0, 1 blocks, Unrecovered Read Error (sct 0x2 / sc 0x81) DNR - Read(0x2) @ LBA 0, 1 blocks, Unknown (sct 0x3 / sc 0x75) DNR - Write(0x1) @ LBA 0, 1 blocks, Write Fault (sct 0x2 / sc 0x80) DNR Identify(0x6), Access Denied (sct 0x2 / sc 0x86) DNR cdw10=0x1 cdw11=0x0 cdw12=0x0 cdw13=0x0 cdw14=0x0 cdw15=0x0 - Read(0x2), Invalid Command Opcode (sct 0x0 / sc 0x1) DNR cdw10=0x0 cdw11=0x0 cdw12=0x1 cdw13=0x0 cdw14=0x0 cdw15=0x0 Test complete The test case does error injection. Test method requires reconsideration to adjust to this kernel change, probably. Help for fix will be appreciated.
Not really an issue with the test, rather the error injector is broken. I'll investigate.
Alan
