Re: [PATCH] fs: show locked and lock_ro options in mountinfo

From: Richard Weinberger
Date: Fri Mar 27 2015 - 17:42:43 EST


On Fri, Mar 27, 2015 at 9:39 PM, Andrey Vagin <avagin@xxxxxxxxxx> wrote:
> I don't see any reasons to hide them. This information can help to
> understand errors.

Because these flags are set/read only internally by the VFS. In contrast
to the other flags shown by mountinfo MNT_LOCKED is not a mount option.

Why does it help to debug errors?
How would a user know that mount() with MS_BIND returns EINVAL because
the mount source is MNT_LOCKED? This information is useless for her.
If you argue like that you'd have to expose the whole VFS state to userland.

> And this information is required for correct checkpoint/restore of mount
> namespaces.

Why especially MNT_LOCKED and not all the other flags used by VFS?
Say MNT_DOOMED?

--
Thanks,
//richard
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