Thanks for analysis and preparing the patch! LGTM - gave it a spin on a VM (with nested guest for testing) on kernel 6.8 - works as expected.
Tested-by: Stoiko Ivanov <s.iva...@proxmox.com> Reviewed-by: Stoiko Ivanov <s.iva...@proxmox.com> On Tue, 11 Mar 2025 09:44:03 +0100 Fabian Grünbichler <f.gruenbich...@proxmox.com> wrote: > this broke with 2.2.7, and can potentially cause data loss or > inconsistency. the patch basically reverts to pre-2.2.7 behaviour, > verified via a fio benchmark. > > reported on our forum: https://forum.proxmox.com/threads/163066 > > upstream PR: https://github.com/openzfs/zfs/pull/17131 > > Signed-off-by: Fabian Grünbichler <f.gruenbich...@proxmox.com> > --- > module only change, needs kernel bump to be active > > ...vols-correctly-detect-flush-requests.patch | 58 +++++++++++++++++++ > debian/patches/series | 1 + > 2 files changed, 59 insertions(+) > create mode 100644 > debian/patches/0012-linux-zvols-correctly-detect-flush-requests.patch > > diff --git > a/debian/patches/0012-linux-zvols-correctly-detect-flush-requests.patch > b/debian/patches/0012-linux-zvols-correctly-detect-flush-requests.patch > new file mode 100644 > index 0000000..609934a > --- /dev/null > +++ b/debian/patches/0012-linux-zvols-correctly-detect-flush-requests.patch > @@ -0,0 +1,58 @@ > +From c9ae14e064f961709557fdcbdb40e692a97225ec Mon Sep 17 00:00:00 2001 > +From: =?UTF-8?q?Fabian=20Gr=C3=BCnbichler?= <f.gruenbich...@proxmox.com> > +Date: Mon, 10 Mar 2025 15:51:09 +0100 > +Subject: [PATCH] linux: zvols: correctly detect flush requests > +MIME-Version: 1.0 > +Content-Type: text/plain; charset=UTF-8 > +Content-Transfer-Encoding: 8bit > + > +since 4.10, bio->bi_opf needs to be checked to determine all kinds of > +flush requests. this was the case prior to the commit referenced below, > +but the order of ifdefs was not the usual one (newest up top), which > +might have caused this to slip through. > + > +this fixes a regression when using zvols as Qemu block devices, but > +might have broken other use cases as well. the symptoms are that all > +sync writes from within a VM configured to use such a virtual block > +devices are ignored and treated as async writes by the host ZFS layer. > + > +this can be verified using fio in sync mode inside the VM, for example > +with > + > + fio \ > + --filename=/dev/sda --ioengine=libaio --loops=1 --size=10G \ > + --time_based --runtime=60 --group_reporting --stonewall --name=cc1 \ > + --description="CC1" --rw=write --bs=4k --direct=1 --iodepth=1 \ > + --numjobs=1 --sync=1 > + > +which shows an IOPS number way above what the physical device underneath > +supports, with "zpool iostat -r 1" on the hypervisor side showing no > +sync IO occuring during the benchmark. > + > +with the regression fixed, both fio inside the VM and the IO stats on > +the host show the expected numbers. > + > +Fixes: 846b5985192467acabf5484ae610b4b37b7f8162 > +"config: remove HAVE_REQ_OP_* and HAVE_REQ_*" > + > +Signed-off-by: Fabian Grünbichler <f.gruenbich...@proxmox.com> > +--- > + include/os/linux/kernel/linux/blkdev_compat.h | 2 +- > + 1 file changed, 1 insertion(+), 1 deletion(-) > + > +diff --git a/include/os/linux/kernel/linux/blkdev_compat.h > b/include/os/linux/kernel/linux/blkdev_compat.h > +index d96708c60..084869c34 100644 > +--- a/include/os/linux/kernel/linux/blkdev_compat.h > ++++ b/include/os/linux/kernel/linux/blkdev_compat.h > +@@ -383,7 +383,7 @@ bio_set_flush(struct bio *bio) > + static inline boolean_t > + bio_is_flush(struct bio *bio) > + { > +- return (bio_op(bio) == REQ_OP_FLUSH); > ++ return (bio_op(bio) == REQ_OP_FLUSH) || (op_is_flush(bio->bi_opf)); > + } > + > + /* > +-- > +2.39.5 > + > diff --git a/debian/patches/series b/debian/patches/series > index 229027f..938488c 100644 > --- a/debian/patches/series > +++ b/debian/patches/series > @@ -9,3 +9,4 @@ > 0009-arc-stat-summary-guard-access-to-freshly-introduced-.patch > 0010-Fix-nfs_truncate_shares-without-etc-exports.d.patch > 0011-zpool-status-tighten-bounds-for-noalloc-stat-availab.patch > +0012-linux-zvols-correctly-detect-flush-requests.patch _______________________________________________ pve-devel mailing list pve-devel@lists.proxmox.com https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel
