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authorChristoph Hellwig <hch@lst.de>2015-04-30 12:49:24 +0300
committerJ. Bruce Fields <bfields@redhat.com>2015-05-04 19:02:41 +0300
commitcba5f62b1830c1919b47544789bc993e6e617dc6 (patch)
tree6f85f8982fe083ea576b7938799e56fe4d675bec /fs/nfsd/nfs4callback.c
parentef2a1b3e1067195f1d6b89d8329454775c87f033 (diff)
downloadlinux-cba5f62b1830c1919b47544789bc993e6e617dc6.tar.xz
nfsd: fix callback restarts
Checking the rpc_client pointer is not a reliable way to detect backchannel changes: cl_cb_client is changed only after shutting down the rpc client, so the condition cl_cb_client = tk_client will always be true. Check the RPC_TASK_KILLED flag instead, and rewrite the code to avoid the buggy cl_callbacks list and fix the lifetime rules due to double calls of the ->prepare callback operations method for this retry case. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'fs/nfsd/nfs4callback.c')
-rw-r--r--fs/nfsd/nfs4callback.c52
1 files changed, 23 insertions, 29 deletions
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index cd58b7cd3f1a..4c993aaf1e6e 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -879,13 +879,6 @@ static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
if (!nfsd41_cb_get_slot(clp, task))
return;
}
- spin_lock(&clp->cl_lock);
- if (list_empty(&cb->cb_per_client)) {
- /* This is the first call, not a restart */
- cb->cb_done = false;
- list_add(&cb->cb_per_client, &clp->cl_callbacks);
- }
- spin_unlock(&clp->cl_lock);
rpc_call_start(task);
}
@@ -907,16 +900,21 @@ static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
clp->cl_cb_session->se_cb_seq_nr);
}
- if (clp->cl_cb_client != task->tk_client) {
- /* We're shutting down or changing cl_cb_client; leave
- * it to nfsd4_process_cb_update to restart the call if
- * necessary. */
+ /*
+ * If the backchannel connection was shut down while this
+ * task was queued, we need to resubmit it after setting up
+ * a new backchannel connection.
+ *
+ * Note that if we lost our callback connection permanently
+ * the submission code will error out, so we don't need to
+ * handle that case here.
+ */
+ if (task->tk_flags & RPC_TASK_KILLED) {
+ task->tk_status = 0;
+ cb->cb_need_restart = true;
return;
}
- if (cb->cb_done)
- return;
-
if (cb->cb_status) {
WARN_ON_ONCE(task->tk_status);
task->tk_status = cb->cb_status;
@@ -936,21 +934,17 @@ static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
default:
BUG();
}
- cb->cb_done = true;
}
static void nfsd4_cb_release(void *calldata)
{
struct nfsd4_callback *cb = calldata;
- struct nfs4_client *clp = cb->cb_clp;
-
- if (cb->cb_done) {
- spin_lock(&clp->cl_lock);
- list_del(&cb->cb_per_client);
- spin_unlock(&clp->cl_lock);
+ if (cb->cb_need_restart)
+ nfsd4_run_cb(cb);
+ else
cb->cb_ops->release(cb);
- }
+
}
static const struct rpc_call_ops nfsd4_cb_ops = {
@@ -1045,9 +1039,6 @@ static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
nfsd4_mark_cb_down(clp, err);
return;
}
- /* Yay, the callback channel's back! Restart any callbacks: */
- list_for_each_entry(cb, &clp->cl_callbacks, cb_per_client)
- queue_work(callback_wq, &cb->cb_work);
}
static void
@@ -1058,8 +1049,12 @@ nfsd4_run_cb_work(struct work_struct *work)
struct nfs4_client *clp = cb->cb_clp;
struct rpc_clnt *clnt;
- if (cb->cb_ops && cb->cb_ops->prepare)
- cb->cb_ops->prepare(cb);
+ if (cb->cb_need_restart) {
+ cb->cb_need_restart = false;
+ } else {
+ if (cb->cb_ops && cb->cb_ops->prepare)
+ cb->cb_ops->prepare(cb);
+ }
if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
nfsd4_process_cb_update(cb);
@@ -1085,9 +1080,8 @@ void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
cb->cb_msg.rpc_resp = cb;
cb->cb_ops = ops;
INIT_WORK(&cb->cb_work, nfsd4_run_cb_work);
- INIT_LIST_HEAD(&cb->cb_per_client);
cb->cb_status = 0;
- cb->cb_done = true;
+ cb->cb_need_restart = false;
}
void nfsd4_run_cb(struct nfsd4_callback *cb)