Hello, On Tue, Jul 26, 2022 at 10:01:04AM -1000, Tejun Heo wrote: > On Tue, Jul 26, 2022 at 04:32:46PM +0200, Michal Koutný wrote: > > On Thu, Jul 14, 2022 at 06:38:43PM -1000, Tejun Heo <tj@xxxxxxxxxx> wrote: > > > We allow modifying these mount options via remount. Let's add "no" prefixed > > > variants so that they can be turned off too. > > > > They can be turned off: > > > > > // on v5.19-rc? > > > :~ # grep cg /proc/mounts > > > cgroup2 /sys/fs/cgroup cgroup2 rw,nosuid,nodev,noexec,relatime,nsdelegate 0 0 > > > :~ # mount -t cgroup2 cgroup2 /sys/fs/cgroup/ -oremount > > > :~ # grep cg /proc/mounts > > > cgroup2 /sys/fs/cgroup cgroup2 rw,relatime 0 0 root@test ~# grep cgroup /proc/mounts cgroup2 /sys/fs/cgroup cgroup2 rw,nosuid,nodev,noexec,relatime,nsdelegate,memory_recursiveprot 0 0 root@test ~# mount -o remount,exec /sys/fs/cgroup root@test ~# grep cgroup /proc/mounts cgroup2 /sys/fs/cgroup cgroup2 rw,nosuid,nodev,relatime,nsdelegate,memory_recursiveprot 0 0 root@test ~# mount -o remount /sys/fs/cgroup root@test ~# grep cgroup /proc/mounts cgroup2 /sys/fs/cgroup cgroup2 rw,nosuid,nodev,relatime,nsdelegate,memory_recursiveprot 0 0 root@test ~# mount -o remount,nsdelegate,memory_recursiveprot cgroup2 /sys/fs/cgroup root@test ~# grep cgroup /proc/mounts cgroup2 /sys/fs/cgroup cgroup2 rw,relatime,nsdelegate,memory_recursiveprot 0 0 root@test ~# mount -o remount,memory_recursiveprot cgroup2 /sys/fs/cgroup root@test ~# grep cgroup /proc/mounts cgroup2 /sys/fs/cgroup cgroup2 rw,relatime,memory_recursiveprot 0 0 root@test ~# mount -o remount cgroup2 /sys/fs/cgroup root@test ~# grep cgroup /proc/mounts cgroup2 /sys/fs/cgroup cgroup2 rw,relatime 0 0 Man, I had no idea that `mount -o remount,$OPTS $MOUNT_POINT` and `mount -o remount,$OPTS $SRC $MOUNT_POINT` behave completely differently in how they handle existing options. I wonder why other filesystems are implementing explicit no prefixed options. Anyways, will soon post a patch to remove the no prefixed options. Thanks for pointing it out. -- tejun
