On Wed, 28 May 2025 at 15:13, Karel Zak <kzak@xxxxxxxxxx> wrote: > Why can't filesystems silently ignore fsconfig() requests that do not > introduce a change? For example, if the current setting is foo=123 and > fsconfig() is used to change it to foo=123, why is it reported as an > error? It's stupid, but just no op. It's a workaround for legacy behavior. For overlayfs it doesn't make sense to specify "lowerdir=" option for reconfigure and as such it is rejected. What you suggest is a hack, which if there was no other way I'd accept, but I think there are better ways to fix this. > I'm not sure I understand how it will affect userspace. Do you mean > that with the flag, the kernel will assume a completely new set of > options from userspace, and the filesystem will adapt (if possible) to > the new settings? Maybe the naming wasn't good. I meant the opposite of what you describe: the kernel would guarantee that only the supplied options change. This is already what sane filesystems do and they would not have to be changed at all to support this flag. Or maybe all filesystems do this? I haven't checked, but I assumed that libmount does the "append to current options" even for the new API because without it some fs are broke. Thanks, Miklos > > Karel > > -- > Karel Zak <kzak@xxxxxxxxxx> > http://karelzak.blogspot.com >
