Date: Wed, 30 Jan 2019 14:30:59 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 235322] it should be possible to remount nullfs mount from readonly to writable and back Message-ID: <bug-235322-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D235322 Bug ID: 235322 Summary: it should be possible to remount nullfs mount from readonly to writable and back Product: Base System Version: 12.0-RELEASE Hardware: Any OS: Any Status: New Severity: Affects Many People Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: eto.freebsd@ethome.sk This has been bugging me for quite some time, but it seems, that it is impossible to remount nullfs mount from "ro" to "rw" and back, without actu= ally unmounting it first and then remounting it back the other way. Since nobody seems to know or cares about it, I am creating this bug. Case in point: 01 # mkdir ~/test 02 # mount -o ro -t nullfs /etc /usr/home/eto/test So far all is good, but now: 01 # mount -o rw /usr/home/eto/test 02 > mount: /usr/home/eto/test: unknown special file or file system 03 # mount -o rw /etc /usr/home/eto/test 04 > mount: /etc: Block device required It's been some time when I played with nmount() from C, but if I remember correctly, one gets "not supported" error when trying to update mount flags. I tried to look at nullfs code, but it's hard to follow for non-kernel experienced programmers. Anyway I believe sysadmins should be able to change writability flags of nu= ffs mounts (like when updating jails). "ro" mounted jails are very sturdy and protected against unexpected modifications, but are quite the hassle during base updates. --=20 You are receiving this mail because: You are the assignee for the bug.=
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