Re: [PATCH 00/19 v5] Fix filesystem freezing deadlocks

From: Andreas Dilger
Date: Mon Apr 16 2012 - 17:59:55 EST


On 2012-04-16, at 9:13 AM, Jan Kara wrote:
> Another potential contention point might be patch 19. In that patch
> we make freeze_super() refuse to freeze the filesystem when there
> are open but unlinked files which may be impractical in some cases.
> The main reason for this is the problem with handling of file deletion
> from fput() called with mmap_sem held (e.g. from munmap(2)), and
> then there's the fact that we cannot really force such filesystem
> into a consistent state... But if people think that freezing with
> open but unlinked files should happen, then I have some possible
> solutions in mind (maybe as a separate patchset since this is
> large enough).

Looking at a desktop system, I think it is very typical that there
are open-unlinked files present, so I don't know if this is really
an acceptable solution. It isn't clear from your comments whether
this is a blanket refusal for all open-unlinked files, or only in
some particular cases...

lsof | grep deleted
nautilus 25393 adilger 19r REG 253,0 340 253954 /home/adilger/.local/share/gvfs-metadata/home (deleted)
nautilus 25393 adilger 20r REG 253,0 32768 253964 /home/adilger/.local/share/gvfs-metadata/home-f332a8f3.log (deleted)
gnome-ter 25623 adilger 22u REG 0,18 17841 2717846 /tmp/vtePIRJCW (deleted)
gnome-ter 25623 adilger 23u REG 0,18 5568 2717847 /tmp/vteDCSJCW (deleted)
gnome-ter 25623 adilger 29u REG 0,18 480 2728484 /tmp/vte6C1TCW (deleted)

Cheers, Andreas





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