From 931ee56c67573eb4e51c8a4e78598d965b8b059e 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 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 Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields --- fs/nfsd/nfs4state.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) (limited to 'fs/nfsd') diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 01a0e4384500..05ca64c4599d 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); @@ -3065,11 +3074,12 @@ 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); @@ -3090,9 +3100,8 @@ 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; } @@ -4903,6 +4912,7 @@ 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); -- cgit v1.2.3