[add tytso to cc since he asked about "How do you actually /get/ fsdax mode these days?" this morning] On Tue, Oct 25, 2022 at 10:56:19AM -0700, Darrick J. Wong wrote: > On Tue, Oct 25, 2022 at 02:26:50PM +0000, ruansy.fnst@xxxxxxxxxxx wrote: > > > > > > 在 2022/10/24 13:31, Dave Chinner 写道: > > > On Mon, Oct 24, 2022 at 03:17:52AM +0000, ruansy.fnst@xxxxxxxxxxx wrote: > > >> 在 2022/10/24 6:00, Dave Chinner 写道: > > >>> On Fri, Oct 21, 2022 at 07:11:02PM -0700, Darrick J. Wong wrote: > > >>>> On Thu, Oct 20, 2022 at 10:17:45PM +0800, Yang, Xiao/杨 晓 wrote: > > >>>>> In addition, I don't like your idea about the test change because it will > > >>>>> make generic/470 become the special test for XFS. Do you know if we can fix > > >>>>> the issue by changing the test in another way? blkdiscard -z can fix the > > >>>>> issue because it does zero-fill rather than discard on the block device. > > >>>>> However, blkdiscard -z will take a lot of time when the block device is > > >>>>> large. > > >>>> > > >>>> Well we /could/ just do that too, but that will suck if you have 2TB of > > >>>> pmem. ;) > > >>>> > > >>>> Maybe as an alternative path we could just create a very small > > >>>> filesystem on the pmem and then blkdiscard -z it? > > >>>> > > >>>> That said -- does persistent memory actually have a future? Intel > > >>>> scuttled the entire Optane product, cxl.mem sounds like expansion > > >>>> chassis full of DRAM, and fsdax is horribly broken in 6.0 (weird kernel > > >>>> asserts everywhere) and 6.1 (every time I run fstests now I see massive > > >>>> data corruption). > > >>> > > >>> Yup, I see the same thing. fsdax was a train wreck in 6.0 - broken > > >>> on both ext4 and XFS. Now that I run a quick check on 6.1-rc1, I > > >>> don't think that has changed at all - I still see lots of kernel > > >>> warnings, data corruption and "XFS_IOC_CLONE_RANGE: Invalid > > >>> argument" errors. > > >> > > >> Firstly, I think the "XFS_IOC_CLONE_RANGE: Invalid argument" error is > > >> caused by the restrictions which prevent reflink work together with DAX: > > >> > > >> a. fs/xfs/xfs_ioctl.c:1141 > > >> /* Don't allow us to set DAX mode for a reflinked file for now. */ > > >> if ((fa->fsx_xflags & FS_XFLAG_DAX) && xfs_is_reflink_inode(ip)) > > >> return -EINVAL; > > >> > > >> b. fs/xfs/xfs_iops.c:1174 > > >> /* Only supported on non-reflinked files. */ > > >> if (xfs_is_reflink_inode(ip)) > > >> return false; > > >> > > >> These restrictions were removed in "drop experimental warning" patch[1]. > > >> I think they should be separated from that patch. > > >> > > >> [1] > > >> https://lore.kernel.org/linux-xfs/1663234002-17-1-git-send-email-ruansy.fnst@xxxxxxxxxxx/ > > >> > > >> > > >> Secondly, how the data corruption happened? > > > > > > No idea - i"m just reporting that lots of fsx tests failed with data > > > corruptions. I haven't had time to look at why, I'm still trying to > > > sort out the fix for a different data corruption... > > > > > >> Or which case failed? > > > > > > *lots* of them failed with kernel warnings with reflink turned off: > > > > > > SECTION -- xfs_dax_noreflink > > > ========================= > > > Failures: generic/051 generic/068 generic/075 generic/083 > > > generic/112 generic/127 generic/198 generic/231 generic/247 > > > generic/269 generic/270 generic/340 generic/344 generic/388 > > > generic/461 generic/471 generic/476 generic/519 generic/561 xfs/011 > > > xfs/013 xfs/073 xfs/297 xfs/305 xfs/517 xfs/538 > > > Failed 26 of 1079 tests > > > > > > All of those except xfs/073 and generic/471 are failures due to > > > warnings found in dmesg. > > > > > > With reflink enabled, I terminated the run after g/075, g/091, g/112 > > > and generic/127 reported fsx data corruptions and g/051, g/068, > > > g/075 and g/083 had reported kernel warnings in dmesg. > > > > > >> Could > > >> you give me more info (such as mkfs options, xfstests configs)? > > > > > > They are exactly the same as last time I reported these problems. > > > > > > For the "no reflink" test issues: > > > > > > mkfs options are "-m reflink=0,rmapbt=1", mount options "-o > > > dax=always" for both filesytems. Config output at start of test > > > run: > > > > > > SECTION -- xfs_dax_noreflink > > > FSTYP -- xfs (debug) > > > PLATFORM -- Linux/x86_64 test3 6.1.0-rc1-dgc+ #1615 SMP PREEMPT_DYNAMIC Wed Oct 19 12:24:16 AEDT 2022 > > > MKFS_OPTIONS -- -f -m reflink=0,rmapbt=1 /dev/pmem1 > > > MOUNT_OPTIONS -- -o dax=always -o context=system_u:object_r:root_t:s0 /dev/pmem1 /mnt/scratch > > > > > > pmem devices are a pair of fake 8GB pmem regions set up by kernel > > > CLI via "memmap=8G!15G,8G!24G". I don't have anything special set up > > > - the kernel config is kept minimal for these VMs - and the only > > > kernel debug option I have turned on for these specific test runs is > > > CONFIG_XFS_DEBUG=y. > > > > Thanks for the detailed info. But, in my environment (and my > > colleagues', and our real server with DCPMM) these failure cases (you > > mentioned above, in dax+non_reflink mode, with same test options) cannot > > reproduce. > > > > Here's our test environment info: > > - Ruan's env: fedora 36(v6.0-rc1) on kvm,pmem 2x4G:file backended > > - Yang's env: fedora 35(v6.1-rc1) on kvm,pmem 2x1G:memmap=1G!1G,1G!2G > > - Server's : Ubuntu 20.04(v6.0-rc1) real machine,pmem 2x4G:real DCPMM > > > > (To quickly confirm the difference, I just ran the failed 26 cases you > > mentioned above.) Except for generic/471 and generic/519, which failed > > even when dax is off, the rest passed. > > > > > > We don't want fsdax to be truned off. Right now, I think the most > > important thing is solving the failed cases in dax+non_reflink mode. > > So, firstly, I have to reproduce those failures. Is there any thing > > wrong with my test environments? I konw you are using 'memmap=XXG!YYG' to > > simulate pmem. So, (to Darrick) could you show me your config of dev > > environment and the 'testcloud'(I am guessing it's a server with real > > nvdimm just like ours)? > > Nope. Since the announcement of pmem as a product, I have had 15 > minutes of acces to one preproduction prototype server with actual > optane DIMMs in them. > > I have /never/ had access to real hardware to test any of this, so it's > all configured via libvirt to simulate pmem in qemu: > https://lore.kernel.org/linux-xfs/YzXsavOWMSuwTBEC@magnolia/ > > /run/mtrdisk/[gh].mem are both regular files on a tmpfs filesystem: > > $ grep mtrdisk /proc/mounts > none /run/mtrdisk tmpfs rw,relatime,size=82894848k,inode64 0 0 > > $ ls -la /run/mtrdisk/[gh].mem > -rw-r--r-- 1 libvirt-qemu kvm 10739515392 Oct 24 18:09 /run/mtrdisk/g.mem > -rw-r--r-- 1 libvirt-qemu kvm 10739515392 Oct 24 19:28 /run/mtrdisk/h.mem Also forgot to mention that the VM with the fake pmem attached has a script to do: ndctl create-namespace --mode fsdax --map dev -e namespace0.0 -f ndctl create-namespace --mode fsdax --map dev -e namespace1.0 -f Every time the pmem device gets recreated, because apparently that's the only way to get S_DAX mode nowadays? --D > --D > > > > > > > (I just found I only tested on 4G and smaller pmem device. I'll try the > > test on 8G pmem) > > > > > > > > THe only difference between the noreflink and reflink runs is that I > > > drop the "-m reflink=0" mkfs parameter. Otherwise they are identical > > > and the errors I reported are from back-to-back fstests runs without > > > rebooting the VM.... > > > > > > -Dave. > > > > > > -- > > Thanks, > > Ruan.
