On Fri, Jun 6, 2025 at 3:12 AM Zorro Lang <zlang@xxxxxxxxxx> wrote: > > On Thu, Jun 05, 2025 at 08:30:53PM +0200, Amir Goldstein wrote: > > On Thu, Jun 5, 2025 at 7:51 PM Zorro Lang <zlang@xxxxxxxxxx> wrote: > > > > > > On Tue, Jun 03, 2025 at 12:07:40PM +0200, Amir Goldstein wrote: > > > > libmount >= v1.39 calls several unneeded fsconfig() calls to reconfigure > > > > lowerdir/upperdir when user requests only -o remount,ro. > > > > > > > > Those calls fail because overlayfs does not allow making any config > > > > changes with new mount api, besides MS_RDONLY. > > > > > > > > We workaround this problem with --options-mode ignore. > > > > > > > > Reported-by: André Almeida <andrealmeid@xxxxxxxxxx> > > > > Suggested-by: Karel Zak <kzak@xxxxxxxxxx> > > > > Link: https://lore.kernel.org/linux-fsdevel/20250521-ovl_ro-v1-1-2350b1493d94@xxxxxxxxxx/ > > > > Link: https://lore.kernel.org/fstests/CAJfpegtJ3SDKmC80B4AfWiC3JmtWdW2+78fRZVtsuhe-wSRPvg@xxxxxxxxxxxxxx/ > > > > Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx> > > > > --- > > > > > > > > Changes since v1 [1]: > > > > - Change workaround from LIBMOUNT_FORCE_MOUNT2 to --options-mode=ignore > > > > > > > > [1] https://lore.kernel.org/fstests/20250526143500.1520660-1-amir73il@xxxxxxxxx/ > > > > > > I'm not sure if I understand clearly. Does overlay list are fixing this issue > > > on kernel side, then providing a workaround to fstests to avoid the issue be > > > triggered too? > > > > > > > Noone agreed to fix it on the kernel side. > > At least not yet. > > If so, I have two questions:) > 1) Will overlay fix it on kernel or mount util side? This is not known at this time. > 2) Do you plan to keep this workaround until the issue be fixed in one day? > Then revert this workaround? Maybe, but keep in mind that the workaround is simply telling the library what we want to do. We want to remount overlay ro and nothing else and that is exactly what "--options-mode ignore" tells the library to do. I could have just as well written a test helper src/remount_rdonly.c and not have to deal with the question of which libmount version the test machine is using. Note that the tests in question are not intended to test the remount,ro functionality itself, they are intended to test the behavior of fs in some scenarios involving a rdonly mount. I do not want to lose important test coverage of these scenarios because of regressions in the kernel/libmount API. We can add a new test that ONLY tests remount,ro and let that test fail on overlayfs to keep us reminded of the real regresion that needs to be fixed, but the "workaround" or as I prefer to call it "using the right tool for the test case" has to stay for those other tests. Thanks, Amir.
