NFSv4: Use RCU to protect delegations
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/delegation.h b/fs/nfs/delegation.h
index 8f79a31..5874ce7 100644
--- a/fs/nfs/delegation.h
+++ b/fs/nfs/delegation.h
@@ -22,6 +22,7 @@
long flags;
loff_t maxsize;
__u64 change_attr;
+ struct rcu_head rcu;
};
int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res);
@@ -45,11 +46,16 @@
static inline int nfs_have_delegation(struct inode *inode, int flags)
{
+ struct nfs_delegation *delegation;
+ int ret = 0;
+
flags &= FMODE_READ|FMODE_WRITE;
- smp_rmb();
- if ((NFS_I(inode)->delegation_state & flags) == flags)
- return 1;
- return 0;
+ rcu_read_lock();
+ delegation = rcu_dereference(NFS_I(inode)->delegation);
+ if (delegation != NULL && (delegation->type & flags) == flags)
+ ret = 1;
+ rcu_read_unlock();
+ return ret;
}
#else