Commit 502aa0a5 authored Aug 10, 2016 by Josef Bacik Committed by J. Bruce Fields Aug 11, 2016

nfsd: fix dentry refcounting on create



b44061d0 introduced a dentry ref counting bug.  Previously we were
grabbing one ref to dchild in nfsd_create(), but with the creation of
nfsd_create_locked() we have a ref for dchild from the lookup in
nfsd_create(), and then another ref in nfsd_create_locked().  The ref
from the lookup in nfsd_create() is never dropped and results in
dentries still in use at unmount.

Signed-off-by: Josef Bacik <jbacik@fb.com>
Fixes: b44061d0 "nfsd: reorganize nfsd_create"
Reported-by: kernel test robot <xiaolong.ye@intel.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

parent 29b4817d

fs/nfsd/vfs.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -1252,10 +1252,13 @@ nfsd_create(struct svc_rqst rqstp, struct svc_fh fhp,
		if (IS_ERR(dchild))
		return nfserrno(host_err);
		err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
		if (err) {
		/*
		* We unconditionally drop our ref to dchild as fh_compose will have
		* already grabbed its own ref for it.
		*/
		dput(dchild);
		if (err)
		return err;
		}
		return nfsd_create_locked(rqstp, fhp, fname, flen, iap, type,
		rdev, resfhp);
		}