Some filesystem flags seem to be hidden in /proc/mounts, depending on whether they are defined as defaults.
Is there a way to show all flags in /proc/mounts, also including the default ones? And if not, is there another command to see all enabled flags for the mounted filesystems?
My background: I have set the data=writeback flag in fstab and also passed it to the kernel in my grub configuration, but it is still not listed in /proc/mounts. Now, how can I find out whether this is because data=writeback is a default (and thus not shown), or because the flag is indeed not set?