From ba1ef838a9e275933683edbd08b6e2226f16e351 Mon Sep 17 00:00:00 2001 From: Benny Halevy Date: Fri, 30 May 2014 09:09:27 -0400 Subject: nfsd4: use recall_lock for delegation hashing commit 931ee56c67573eb4e51c8a4e78598d965b8b059e upstream. 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 Signed-off-by: J. Bruce Fields [bwh: Backported to 3.2: - Adjust context - Also remove a list_del_init() in nfs4_setlease() which would now be before the corresponding list_add() - Drop change to nfsd_find_all_delegations(), which doesn't exist] Signed-off-by: Ben Hutchings --- fs/nfsd/nfs4state.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) (limited to 'fs') diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index b2e0a5585aed..7e1a7a8f2370 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -337,13 +337,22 @@ static void unhash_stid(struct nfs4_stid *s) idr_remove(stateids, s->sc_stateid.si_opaque.so_id); } +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) { unhash_stid(&dp->dl_stid); - 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); @@ -2810,10 +2819,8 @@ static int nfs4_setlease(struct nfs4_delegation *dp, int flag) if (!fl) return -ENOMEM; fl->fl_file = find_readable_file(fp); - list_add(&dp->dl_perclnt, &dp->dl_stid.sc_client->cl_delegations); status = vfs_setlease(fl->fl_file, fl->fl_type, &fl); if (status) { - list_del_init(&dp->dl_perclnt); locks_free_lock(fl); return -ENOMEM; } @@ -2821,7 +2828,9 @@ static int nfs4_setlease(struct nfs4_delegation *dp, int flag) fp->fi_deleg_file = fl->fl_file; get_file(fp->fi_deleg_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; } @@ -2837,9 +2846,8 @@ static int nfs4_set_delegation(struct nfs4_delegation *dp, int flag) return -EAGAIN; } atomic_inc(&fp->fi_delegees); - 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; } -- cgit v1.2.3