For a similar issue in cifs vfs (samba bugzilla 8950), I was going to try unset the bit DCACHE_OP_REVALIDATE of d_flags of the dentry. Would something like work for the mountpoint dentry? On Mon, Nov 4, 2013 at 7:16 PM, Jeff Layton <jlayton@xxxxxxxxxx> wrote: > We had a couple of reports of people that are mounting NFS filesystems, > and then bind mounting certain local files onto dentries in that nfs > mount (sort of like a poor-man's unionmount). > > This all works well until the dentry serving as the mountpoint fails > d_revalidate. The dentry will end up being invalidated which makes the > bind mount unreachable via pathwalk. > > It doesn't make much sense to me to allow dentries to serve as > mountpoints to end up invalidated, so there's no real point in > attempting to d_revalidate them at all. > > Reported-by: Patrick McLean <chutzpah@xxxxxxxxxx> > Reported-by: Guang Cheng Li <liguangc@xxxxxxxxxx> > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> > --- > fs/namei.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/fs/namei.c b/fs/namei.c > index caa2805..5b10ad0 100644 > --- a/fs/namei.c > +++ b/fs/namei.c > @@ -585,6 +585,9 @@ drop_root_mnt: > > static inline int d_revalidate(struct dentry *dentry, unsigned int flags) > { > + /* dentries that serve as mountpoints are always considered valid */ > + if (d_mountpoint(dentry)) > + return 1; > return dentry->d_op->d_revalidate(dentry, flags); > } > > -- > 1.8.3.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html