NFSv4: Fix atomicity problems with lock stateid updates

When we update the lock stateid, we really do need to ensure that this is
done under the state->state_lock, and that we are indeed only updating
confirmed locks with a newer version of the same stateid.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 0a279ad..db9d98e 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1297,6 +1297,23 @@ no_delegation:
        return ret;
 }
 
+static bool nfs4_update_lock_stateid(struct nfs4_lock_state *lsp,
+               const nfs4_stateid *stateid)
+{
+       struct nfs4_state *state = lsp->ls_state;
+       bool ret = false;
+
+       spin_lock(&state->state_lock);
+       if (!nfs4_stateid_match_other(stateid, &lsp->ls_stateid))
+               goto out_noupdate;
+       if (!nfs4_stateid_is_newer(stateid, &lsp->ls_stateid))
+               goto out_noupdate;
+       nfs4_stateid_copy(&lsp->ls_stateid, stateid);
+       ret = true;
+out_noupdate:
+       spin_unlock(&state->state_lock);
+       return ret;
+}
 
 static void nfs4_return_incompatible_delegation(struct inode *inode, fmode_t fmode)
 {
@@ -5403,9 +5420,9 @@ static void nfs4_locku_done(struct rpc_task *task, void *data)
                return;
        switch (task->tk_status) {
                case 0:
-                       nfs4_stateid_copy(&calldata->lsp->ls_stateid,
-                                       &calldata->res.stateid);
                        renew_lease(calldata->server, calldata->timestamp);
+                       nfs4_update_lock_stateid(calldata->lsp,
+                                       &calldata->res.stateid);
                        break;
                case -NFS4ERR_BAD_STATEID:
                case -NFS4ERR_OLD_STATEID:
@@ -5626,6 +5643,7 @@ out_wait:
 static void nfs4_lock_done(struct rpc_task *task, void *calldata)
 {
        struct nfs4_lockdata *data = calldata;
+       struct nfs4_lock_state *lsp = data->lsp;
 
        dprintk("%s: begin!\n", __func__);
 
@@ -5633,18 +5651,16 @@ static void nfs4_lock_done(struct rpc_task *task, void *calldata)
                return;
 
        data->rpc_status = task->tk_status;
-       if (data->arg.new_lock_owner != 0) {
-               if (data->rpc_status == 0)
-                       nfs_confirm_seqid(&data->lsp->ls_seqid, 0);
-               else
-                       goto out;
-       }
-       if (data->rpc_status == 0) {
-               nfs4_stateid_copy(&data->lsp->ls_stateid, &data->res.stateid);
-               set_bit(NFS_LOCK_INITIALIZED, &data->lsp->ls_flags);
-               renew_lease(NFS_SERVER(data->ctx->dentry->d_inode), data->timestamp);
+       if (task->tk_status == 0) {
+               renew_lease(NFS_SERVER(data->ctx->dentry->d_inode),
+                               data->timestamp);
+               if (data->arg.new_lock_owner != 0) {
+                       nfs_confirm_seqid(&lsp->ls_seqid, 0);
+                       nfs4_stateid_copy(&lsp->ls_stateid, &data->res.stateid);
+                       set_bit(NFS_LOCK_INITIALIZED, &lsp->ls_flags);
+               } else if (!nfs4_update_lock_stateid(lsp, &data->res.stateid))
+                       rpc_restart_call_prepare(task);
        }
-out:
        dprintk("%s: done, ret = %d!\n", __func__, data->rpc_status);
 }