@@ -7055,7 +7055,7 @@ nfsd4_open_downgrade(struct svc_rqst *rqstp,
return status;
}
-static void nfsd4_close_open_stateid(struct nfs4_ol_stateid *s)
+static bool nfsd4_close_open_stateid(struct nfs4_ol_stateid *s)
{
struct nfs4_client *clp = s->st_stid.sc_client;
bool unhashed;
@@ -7072,11 +7072,11 @@ static void nfsd4_close_open_stateid(struct nfs4_ol_stateid *s)
list_for_each_entry(stp, &reaplist, st_locks)
nfs4_free_cpntf_statelist(clp->net, &stp->st_stid);
free_ol_stateid_reaplist(&reaplist);
+ return false;
} else {
spin_unlock(&clp->cl_lock);
free_ol_stateid_reaplist(&reaplist);
- if (unhashed)
- move_to_close_lru(s, clp->net);
+ return unhashed;
}
}
@@ -7092,6 +7092,7 @@ nfsd4_close(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
struct nfs4_ol_stateid *stp;
struct net *net = SVC_NET(rqstp);
struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+ bool need_move_to_close_list;
dprintk("NFSD: nfsd4_close on file %pd\n",
cstate->current_fh.fh_dentry);
@@ -7114,8 +7115,10 @@ nfsd4_close(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
*/
nfs4_inc_and_copy_stateid(&close->cl_stateid, &stp->st_stid);
- nfsd4_close_open_stateid(stp);
+ need_move_to_close_list = nfsd4_close_open_stateid(stp);
mutex_unlock(&stp->st_mutex);
+ if (need_move_to_close_list)
+ move_to_close_lru(stp, net);
/* v4.1+ suggests that we send a special stateid in here, since the
* clients should just ignore this anyway. Since this is not useful
move_to_close_lru() is currently called with ->st_mutex held. This can lead to a deadlock as move_to_close_lru() waits for sc_count to drop to 2, and some threads holding a reference might be waiting for the mutex. These references will never be dropped so sc_count will never reach 2. There can be no harm in dropping ->st_mutex to before move_to_close_lru() because the only place that takes the mutex is nfsd4_lock_ol_stateid(), and it quickly aborts if sc_type is NFS4_CLOSED_STID, which it will be before move_to_close_lru() is called. See also https://lore.kernel.org/lkml/4dd1fe21e11344e5969bb112e954affb@jd.com/T/ where this problem was raised but not successfully resolved. Signed-off-by: NeilBrown <neilb@suse.de> --- fs/nfsd/nfs4state.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)