Currently, both destroy_revoked_delegation and revoke_delegation
manipulate the cl_revoked list without any locking. Ensure that the
clp->cl_lock is held when manipulating it, except for the list walking
in destroy_client. At that point, the client should no longer be in use,
so we should be safe to walk the list without any locking, which also
means that we don't need to do the list_splice_init there either.
Also, the fact that destroy_revoked_delegation and revoke_delegation
delete dl_recall_lru without any locking makes it difficult to know
whether they're doing so safely in all cases. Move the list_del_init
calls into the callers, and add WARN_ONs in the event that these calls
are passed a delegation that has a non-empty list.
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
---
fs/nfsd/nfs4state.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 561c77a02920..8267531ed455 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -649,7 +649,7 @@ static void unhash_and_destroy_delegation(struct nfs4_delegation *dp)
static void destroy_revoked_delegation(struct nfs4_delegation *dp)
{
- list_del_init(&dp->dl_recall_lru);
+ WARN_ON(!list_empty(&dp->dl_recall_lru));
nfs4_put_delegation(dp);
}
@@ -657,11 +657,15 @@ static void revoke_delegation(struct nfs4_delegation *dp)
{
struct nfs4_client *clp = dp->dl_stid.sc_client;
+ WARN_ON(!list_empty(&dp->dl_recall_lru));
+
if (clp->cl_minorversion == 0)
destroy_revoked_delegation(dp);
else {
dp->dl_stid.sc_type = NFS4_REVOKED_DELEG_STID;
- list_move(&dp->dl_recall_lru, &clp->cl_revoked);
+ spin_lock(&clp->cl_lock);
+ list_add(&dp->dl_recall_lru, &clp->cl_revoked);
+ spin_unlock(&clp->cl_lock);
}
}
@@ -1459,9 +1463,9 @@ __destroy_client(struct nfs4_client *clp)
list_del_init(&dp->dl_recall_lru);
destroy_delegation(dp);
}
- list_splice_init(&clp->cl_revoked, &reaplist);
- while (!list_empty(&reaplist)) {
+ while (!list_empty(&clp->cl_revoked)) {
dp = list_entry(reaplist.next, struct nfs4_delegation, dl_recall_lru);
+ list_del_init(&dp->dl_recall_lru);
destroy_revoked_delegation(dp);
}
while (!list_empty(&clp->cl_openowners)) {
@@ -4391,6 +4395,11 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
break;
case NFS4_REVOKED_DELEG_STID:
dp = delegstateid(s);
+
+ spin_lock(&cl->cl_lock);
+ list_del_init(&dp->dl_recall_lru);
+ spin_unlock(&cl->cl_lock);
+
destroy_revoked_delegation(dp);
ret = nfs_ok;
break;
--
1.9.3
--
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