On Tuesday, March 03/17/20, 2020 at 09:39:39 -0700, Sagi Grimberg wrote: > > >>>For TCP we can set BDI_CAP_STABLE_WRITES. For RDMA I don't think > >>that > >>>is a good idea as pretty much all RDMA block drivers rely on the > >>>DMA behavior above. The answer is to bounce buffer the data in > >>>SoftiWARP / SoftRoCE. > >> > >>We already do, see nvme_alloc_ns. > >> > >> > > > >Krishna was getting the issue when testing TCP/NVMeF with -G > >during connect. That enables data digest and STABLE_WRITES > >I think. So to me it seems we don't get stable pages, but > >pages which are touched after handover to the provider. > > Non of the transports modifies the data at any point, both will > scan it to compute crc. So surely this is coming from the fs, > Krishna does this happen with xfs as well? Yes, but rare(took ~15min to recreate), whereas with ext3/4 its almost immediate. Here is the error log for NVMe/TCP with xfs. dmesg at Host: [ +0.000323] nvme nvme2: creating 12 I/O queues. [ +0.008991] nvme nvme2: Successfully reconnected (1 attempt) [ +25.277733] blk_update_request: I/O error, dev nvme2n1, sector 0 op 0x3:(DISCARD) flags 0x800 phys_seg 1 prio class 0 [ +6.043879] XFS (nvme2n1): Mounting V5 Filesystem [ +0.017745] XFS (nvme2n1): Ending clean mount [ +0.000174] xfs filesystem being mounted at /mnt supports timestamps until 2038 (0x7fffffff) [Mar18 00:14] nvme nvme2: Reconnecting in 10 seconds... [ +0.000453] nvme nvme2: creating 12 I/O queues. [ +0.009216] nvme nvme2: Successfully reconnected (1 attempt) [Mar18 00:43] nvme nvme2: Reconnecting in 10 seconds... [ +0.000383] nvme nvme2: creating 12 I/O queues. [ +0.009239] nvme nvme2: Successfully reconnected (1 attempt) dmesg at Target: [Mar18 00:14] nvmet_tcp: queue 9: cmd 17 pdu (4) data digest error: recv 0x8e85d882 expected 0x9a46fac3 [ +0.000011] nvmet: ctrl 1 fatal error occurred! [ +10.240266] nvmet: creating controller 1 for subsystem nvme-ram0 for NQN nqn.2014-08.org.nvmexpress.chelsio. [Mar18 00:42] nvmet_tcp: queue 7: cmd 89 pdu (4) data digest error: recv 0xc0ce3dfd expected 0x7ee136b5 [ +0.000012] nvmet: ctrl 1 fatal error occurred! [Mar18 00:43] nvmet: creating controller 1 for subsystem nvme-ram0 for NQN nqn.2014-08.org.nvmexpress.chelsio.
