diff options
| -rw-r--r-- | fs/nfs/delegation.c | 57 |
1 files changed, 53 insertions, 4 deletions
diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c index c454532b6f03..105b0f39a5b2 100644 --- a/fs/nfs/delegation.c +++ b/fs/nfs/delegation.c @@ -483,28 +483,73 @@ out: int nfs_client_return_marked_delegations(struct nfs_client *clp) { struct nfs_delegation *delegation; + struct nfs_delegation *prev; struct nfs_server *server; struct inode *inode; + struct inode *place_holder = NULL; + struct nfs_delegation *place_holder_deleg = NULL; int err = 0; restart: + /* + * To avoid quadratic looping we hold a reference + * to an inode place_holder. Each time we restart, we + * list nfs_servers from the server of that inode, and + * delegation in the server from the delegations of that + * inode. + * prev is an RCU-protected pointer to a delegation which + * wasn't marked for return and might be a good choice for + * the next place_holder. + */ rcu_read_lock(); - list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) { - list_for_each_entry_rcu(delegation, &server->delegations, - super_list) { - if (!nfs_delegation_need_return(delegation)) + prev = NULL; + if (place_holder) + server = NFS_SERVER(place_holder); + else + server = list_entry_rcu(clp->cl_superblocks.next, + struct nfs_server, client_link); + list_for_each_entry_from_rcu(server, &clp->cl_superblocks, client_link) { + delegation = NULL; + if (place_holder && server == NFS_SERVER(place_holder)) + delegation = rcu_dereference(NFS_I(place_holder)->delegation); + if (!delegation || delegation != place_holder_deleg) + delegation = list_entry_rcu(server->delegations.next, + struct nfs_delegation, super_list); + list_for_each_entry_from_rcu(delegation, &server->delegations, super_list) { + struct inode *to_put = NULL; + + if (!nfs_delegation_need_return(delegation)) { + prev = delegation; continue; + } if (!nfs_sb_active(server->super)) break; /* continue in outer loop */ + + if (prev) { + struct inode *tmp; + + tmp = nfs_delegation_grab_inode(prev); + if (tmp) { + to_put = place_holder; + place_holder = tmp; + place_holder_deleg = prev; + } + } + inode = nfs_delegation_grab_inode(delegation); if (inode == NULL) { rcu_read_unlock(); + if (to_put) + iput(to_put); nfs_sb_deactive(server->super); goto restart; } delegation = nfs_start_delegation_return_locked(NFS_I(inode)); rcu_read_unlock(); + if (to_put) + iput(to_put); + err = nfs_end_delegation_return(inode, delegation, 0); iput(inode); nfs_sb_deactive(server->super); @@ -512,10 +557,14 @@ restart: if (!err) goto restart; set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state); + if (place_holder) + iput(place_holder); return err; } } rcu_read_unlock(); + if (place_holder) + iput(place_holder); return 0; } |