[33/70] NFSd: Ensure atomicity of stateid destruction and idr tree removal

Commit Message

Trond Myklebust April 18, 2014, 6:44 p.m. UTC

Signed-off-by: Trond Myklebust <[e-mail]>
---
 fs/nfsd/nfs4state.c | 26 +++++++++++++++-----------
 1 file changed, 15 insertions(+), 11 deletions(-)

Patch

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 7b897ff03a27..f463aaf9cd13 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -461,31 +461,37 @@  alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct sv
 	return dp;
 }
 
-static void remove_stid(struct nfs4_stid *s)
+static void remove_stid_locked(struct nfs4_client *clp, struct nfs4_stid *s)
 {
-	struct nfs4_client *clp = s->sc_client;
 	struct idr *stateids = &clp->cl_stateids;
 
-	spin_lock(&clp->cl_lock);
 	idr_remove(stateids, s->sc_stateid.si_opaque.so_id);
-	spin_unlock(&clp->cl_lock);
 }
 
 static void nfs4_free_stid(struct kmem_cache *slab, struct nfs4_stid *s)
 {
-	remove_stid(s);
 	if (s->sc_file)
 		put_nfs4_file(s->sc_file);
 	kmem_cache_free(slab, s);
 }
 
+static bool nfs4_put_stid(struct kmem_cache *slab, struct nfs4_stid *s)
+{
+	struct nfs4_client *clp = s->sc_client;
+
+	if (!atomic_dec_and_lock(&s->sc_count, &clp->cl_lock))
+		return false;
+	remove_stid_locked(clp, s);
+	spin_unlock(&clp->cl_lock);
+	nfs4_free_stid(slab, s);
+	return true;
+}
+
 void
 nfs4_put_delegation(struct nfs4_delegation *dp)
 {
-	if (atomic_dec_and_test(&dp->dl_stid.sc_count)) {
-		nfs4_free_stid(deleg_slab, &dp->dl_stid);
+	if (nfs4_put_stid(deleg_slab, &dp->dl_stid))
 		num_delegations--;
-	}
 }
 
 /* Call under fp->fi_lock */
@@ -712,9 +718,7 @@  static void close_generic_stateid(struct nfs4_ol_stateid *stp)
 
 static void put_generic_stateid(struct nfs4_ol_stateid *stp)
 {
-	if (!atomic_dec_and_test(&stp->st_stid.sc_count))
-		return;
-	nfs4_free_stid(stateid_slab, &stp->st_stid);
+	nfs4_put_stid(stateid_slab, &stp->st_stid);
 }
 
 static void __release_lock_stateid(struct nfs4_lockowner *lo,