NFS: Avoid unnecessary rescanning of the per-server delegation list

[ Upstream commit f92214e4c312f6ea9d78650cc6291d200f17abb6 ]

If the call to nfs_delegation_grab_inode() fails, we will not have
dropped any locks that require us to rescan the list.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index cf7365581031b5c4442956a6643572580abc9abc..a2034511b6314435a420481cd6add663339c327e 100644 (file)
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -627,6 +627,9 @@ restart:
                                prev = delegation;
                        continue;
                }
+               inode = nfs_delegation_grab_inode(delegation);
+               if (inode == NULL)
+                       continue;
 
                if (prev) {
                        struct inode *tmp = nfs_delegation_grab_inode(prev);
@@ -637,12 +640,6 @@ restart:
                        }
                }
 
-               inode = nfs_delegation_grab_inode(delegation);
-               if (inode == NULL) {
-                       rcu_read_unlock();
-                       iput(to_put);
-                       goto restart;
-               }
                delegation = nfs_start_delegation_return_locked(NFS_I(inode));
                rcu_read_unlock();
 
@@ -1164,7 +1161,6 @@ static int nfs_server_reap_unclaimed_delegations(struct nfs_server *server,
        struct inode *inode;
 restart:
        rcu_read_lock();
-restart_locked:
        list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
                if (test_bit(NFS_DELEGATION_INODE_FREEING,
                                        &delegation->flags) ||
@@ -1175,7 +1171,7 @@ restart_locked:
                        continue;
                inode = nfs_delegation_grab_inode(delegation);
                if (inode == NULL)
-                       goto restart_locked;
+                       continue;
                delegation = nfs_start_delegation_return_locked(NFS_I(inode));
                rcu_read_unlock();
                if (delegation != NULL) {
@@ -1296,7 +1292,6 @@ static int nfs_server_reap_expired_delegations(struct nfs_server *server,
        nfs4_stateid stateid;
 restart:
        rcu_read_lock();
-restart_locked:
        list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
                if (test_bit(NFS_DELEGATION_INODE_FREEING,
                                        &delegation->flags) ||
@@ -1307,7 +1302,7 @@ restart_locked:
                        continue;
                inode = nfs_delegation_grab_inode(delegation);
                if (inode == NULL)
-                       goto restart_locked;
+                       continue;
                spin_lock(&delegation->lock);
                cred = get_cred_rcu(delegation->cred);
                nfs4_stateid_copy(&stateid, &delegation->stateid);