Messages in this thread | | | Date | Mon, 23 Jan 2006 16:57:28 +0100 | From | Jan Blunck <> | Subject | Re: [PATCH] shrink_dcache_parent() races against shrink_dcache_memory() |
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On Mon, Jan 23, Kirill Korotaev wrote:
> > 1. this patch doesn't fix the whole problem. iput() after sb free is > still possible. So busy inodes after umount too. > 2. it has big problems with locking... >
Yes, you're right. I'll fix that and send an updated version.
> >+ goto repeat; > <<<< I would prefer to have "goto repeat" as it was before... > >+ /* out */ > >+ }
Fair.
> >+ if (atomic_add_unless(&dentry->d_count, -1, 1)) > >+ return; > <<<< I would better introduce __dput_locked() w/o atomic_dec_and_test() > instead of using this atomic_add_unless()... > <<<< For me it looks like an obfuscation of a code, which must be clean > and tidy.
Then it isn't dput_locked() anymore and you have to manually dereference before you use __dput_locked(). Doesn't sound better. I'll give it a try ...
> >+ > >+ spin_lock(&dcache_lock); > >+ dput_locked(dentry, &free_list); > >+ spin_unlock(&dcache_lock); > >+ > <<<< 1. locking here is totally broken... spin_unlock() in dentry_iput()
Yes, I totally missed the locking issue here. I'll rework that one.
> <<<< 2. it doesn't help the situation I wrote to you, > <<<< since iput() can be done on inode _after_ sb freeing...
Hmm, will think about that one again. shrink_dcache_parent() and shrink_dcache_memory()/dput() are not racing against each other now since the reference counting is done before giving up dcache_lock and the select_parent could start.
Regards, Jan
-- Jan Blunck jblunck@suse.de SuSE LINUX AG - A Novell company Maxfeldstr. 5 +49-911-74053-608 D-90409 Nürnberg http://www.suse.de - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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