Messages in this thread | | | Date | Fri, 7 Oct 2011 16:21:37 +0100 | From | Hugo Mills <> | Subject | Re: A Plumber’ s Wish List for Linux |
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On Fri, Oct 07, 2011 at 02:46:23PM +0200, Kay Sievers wrote: > On Fri, Oct 7, 2011 at 12:38, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote: > > On Fri, 7 Oct 2011 12:28:46 +0200 Kay Sievers <kay.sievers@vrfy.org> wrote: > > > >> What do you mean would be ugly? > > > > I have an ext4fs. It supports every possible file name allowed by POSIX > > and SuS. What name are you going to use for your 'hidden directory' that > > won't clash with a real file ? > > Ah, no. The label on FAT (similar on NTFS) are 'magic entries' in the > root dir list, not a real file in the root dir. > > We need kernel support for changing a mounted fs, because, unlike > ext4, the blocks containing the strings are inside the fs, which the > kernel might change any time.
It's worth noting that there are similar issues with btrfs around changing label. A common API for it would make sense. The only btrfs patches I've seen to change label after mkfs-time work either as:
* unmounted only, single underlying device only, pure userspace implementation * mounted only, multiple underlying devices, kernel support needed
The kernel-side patches never got integrated, so we're still unable to change the label on the majority of btrfs filesystems.
Changing the UUID for the filesystem is even harder, as I think it's written to every metadata block. I'm not sure we can do that sanely on a mounted filesystem.
Hugo (just a spear-carrier from the btrfs chorus).
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