NFS: Fix a deadlock with lazy umount
We can't allow rpc callback functions like task->tk_ops->rpc_call_prepare()
and task->tk_ops->rpc_call_done() to call mntput() in any way, since
that will cause a deadlock when the call to rpc_shutdown_client() attempts
to wait on 'task' to complete.
We can avoid the above deadlock by moving calls to mntput to
task->tk_ops->rpc_release() callback, since at that time the task will be
marked as completed, and so rpc_shutdown_client won't attempt to wait on
it.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 80c61fdb..69b4158 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -105,8 +105,11 @@
call_rcu_bh(&wdata->task.u.tk_rcu, nfs_writedata_rcu_free);
}
-void nfs_writedata_release(void *wdata)
+void nfs_writedata_release(void *data)
{
+ struct nfs_write_data *wdata = data;
+
+ put_nfs_open_context(wdata->args.context);
nfs_writedata_free(wdata);
}
@@ -816,7 +819,7 @@
data->args.pgbase = req->wb_pgbase + offset;
data->args.pages = data->pagevec;
data->args.count = count;
- data->args.context = req->wb_context;
+ data->args.context = get_nfs_open_context(req->wb_context);
data->args.stable = NFS_UNSTABLE;
if (how & FLUSH_STABLE) {
data->args.stable = NFS_DATA_SYNC;
@@ -1153,8 +1156,11 @@
#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
-void nfs_commit_release(void *wdata)
+void nfs_commit_release(void *data)
{
+ struct nfs_write_data *wdata = data;
+
+ put_nfs_open_context(wdata->args.context);
nfs_commit_free(wdata);
}
@@ -1197,6 +1203,7 @@
/* Note: we always request a commit of the entire inode */
data->args.offset = 0;
data->args.count = 0;
+ data->args.context = get_nfs_open_context(first->wb_context);
data->res.count = 0;
data->res.fattr = &data->fattr;
data->res.verf = &data->verf;