Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-qg0-f49.google.com ([209.85.192.49]:51906 "EHLO mail-qg0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752186AbaE3NJs (ORCPT ); Fri, 30 May 2014 09:09:48 -0400 Received: by mail-qg0-f49.google.com with SMTP id a108so5099728qge.36 for ; Fri, 30 May 2014 06:09:48 -0700 (PDT) From: Jeff Layton To: bfields@fieldses.org Cc: trond.myklebust@primarydata.com, bhalevy@primarydata.com, linux-nfs@vger.kernel.org Subject: [PATCH 3/9] nfsd4: use recall_lock for delegation hashing Date: Fri, 30 May 2014 09:09:27 -0400 Message-Id: <1401455373-18207-4-git-send-email-jlayton@primarydata.com> In-Reply-To: <1401455373-18207-1-git-send-email-jlayton@primarydata.com> References: <1401455373-18207-1-git-send-email-jlayton@primarydata.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: From: Benny Halevy This fixes a bug in the handling of the fi_delegations list. nfs4_setlease does not hold the recall_lock when adding to it. The client_mutex is held, which prevents against concurrent list changes, but nfsd_break_deleg_cb does not hold while walking it. New delegations could theoretically creep onto the list while we're walking it there. Signed-off-by: Benny Halevy Signed-off-by: Jeff Layton --- fs/nfsd/nfs4state.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index be6199cc8711..96bdd90b96b1 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -433,12 +433,21 @@ static void unhash_stid(struct nfs4_stid *s) s->sc_type = 0; } +static void +hash_delegation_locked(struct nfs4_delegation *dp, struct nfs4_file *fp) +{ + lockdep_assert_held(&recall_lock); + + list_add(&dp->dl_perfile, &fp->fi_delegations); + list_add(&dp->dl_perclnt, &dp->dl_stid.sc_client->cl_delegations); +} + /* Called under the state lock. */ static void unhash_delegation(struct nfs4_delegation *dp) { - list_del_init(&dp->dl_perclnt); spin_lock(&recall_lock); + list_del_init(&dp->dl_perclnt); list_del_init(&dp->dl_perfile); list_del_init(&dp->dl_recall_lru); spin_unlock(&recall_lock); @@ -3053,11 +3062,12 @@ static int nfs4_setlease(struct nfs4_delegation *dp) status = vfs_setlease(fl->fl_file, fl->fl_type, &fl); if (status) goto out_free; - list_add(&dp->dl_perclnt, &dp->dl_stid.sc_client->cl_delegations); fp->fi_lease = fl; fp->fi_deleg_file = get_file(fl->fl_file); atomic_set(&fp->fi_delegees, 1); - list_add(&dp->dl_perfile, &fp->fi_delegations); + spin_lock(&recall_lock); + hash_delegation_locked(dp, fp); + spin_unlock(&recall_lock); return 0; out_free: locks_free_lock(fl); @@ -3078,9 +3088,8 @@ static int nfs4_set_delegation(struct nfs4_delegation *dp, struct nfs4_file *fp) spin_unlock(&recall_lock); return -EAGAIN; } - list_add(&dp->dl_perfile, &fp->fi_delegations); + hash_delegation_locked(dp, fp); spin_unlock(&recall_lock); - list_add(&dp->dl_perclnt, &dp->dl_stid.sc_client->cl_delegations); return 0; } @@ -4891,6 +4900,7 @@ static u64 nfsd_find_all_delegations(struct nfs4_client *clp, u64 max, struct nfs4_delegation *dp, *next; u64 count = 0; + lockdep_assert_held(&recall_lock); list_for_each_entry_safe(dp, next, &clp->cl_delegations, dl_perclnt) { if (victims) list_move(&dp->dl_recall_lru, victims); -- 1.9.3