Re: [PATCH] Busy inodes after unmount, be more verbose in generic_shutdown_super

[Kirill Korotaev]

Hello Jan,

> > > mntput(path->mnt);   // too early mntput()
> > > dput(path->dentry);
> > >
> > > Assuming that in-between this sequence someone unmounts the file system, 
> > > your
> > > patch will wait for this dput() to finish before it proceeds with 
> > > unmounting
> > > the file system. I think this isn't what we want.
> >
> > No, it won't wait for anything, because if umount happened between 
> > mntput/dput, dentry is not in s_dshrinkers list.
> > if umount happens in parallell with dput() (where shrinker operations 
> > are), then it will behave ok - will wait for dput() and then umount. It 
> > was intended behaviour!
>
>
> It should not wait.
why?! it makes sure, that dentries/inodes are gone _before_ super block 
destroyed.

> > Also, please, note that such early mntput()'s are bugs!!! because such 
> > dentries can reference freed memory after last mntput(). And I remember 
> > some patches in 2.4.x/2.6.x which fixed this sequence everywhere.
>
>
> Thats why I'm complaining ...
about what?
my patch doesn't hide this bug, nor helps it anyhow.

Kirill


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