Messages in this thread |  | | | Date | Thu, 10 Dec 2009 15:20:20 -0500 | | From | Valerie Aurora <> | | Subject | Re: [PATCH 01/41] VFS: BUG() if somebody tries to rehash an already hashed dentry |
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On Sun, Nov 29, 2009 at 08:43:58PM -0500, Erez Zadok wrote: > In message <1256152779-10054-2-git-send-email-vaurora@redhat.com>, Valerie Aurora writes: > > From: Jan Blunck <jblunck@suse.de> > > > > Break early when somebody tries to rehash an already hashed dentry. > > Otherwise this leads to interesting corruptions in the dcache hash table > > later on. > > > > Signed-off-by: Jan Blunck <jblunck@suse.de> > > Signed-off-by: Valerie Aurora <vaurora@redhat.com> > > --- > > fs/dcache.c | 1 + > > 1 files changed, 1 insertions(+), 0 deletions(-) > > > > diff --git a/fs/dcache.c b/fs/dcache.c > > index 9e5cd3c..38bf982 100644 > > --- a/fs/dcache.c > > +++ b/fs/dcache.c > > @@ -1550,6 +1550,7 @@ void d_rehash(struct dentry * entry) > > { > > spin_lock(&dcache_lock); > > spin_lock(&entry->d_lock); > > + BUG_ON(!d_unhashed(entry)); > > _d_rehash(entry); > > spin_unlock(&entry->d_lock); > > spin_unlock(&dcache_lock); > > This patch seems unrelated to union mounts. If so, can you get it pushed > upstream sooner? Or is this a debugging patch useful only when developing > union mounts? > > You also said that it can lead to "ineresting corruptions". What kind of > corruptions exactly? Also, would it make more sense to allow _d_rehash() to > hash in an unhashed dentry for the first time?
Hi Erez,
Thanks for your great review! I am working my way through your comments one by one.
This is a trivial patch which happened to be useful during our development and seems like it might be useful for other VFS-related development. I will submit it as part of our VFS patch set and drop it if the maintainers don't want it.
I don't have an opinion on _d_rehash(), I'm afraid.
-VAL
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