[PATCH] nfsd: try nfsdcld client tracker in containers

[Stanislav Kinsbursky <skinsbursky@parallels.com>]

Currently, UMH and Legacy trackers are disabled in containers.
But existent logic can lookup nfs4_recoverydir in a container, and in this
case will try to init Legacy tracker and skip nfsdcld client tracker.
This actually means, that no client tracker will be started in a container at
all, because Legacy tracker init will return -EINVAL for a container.
So, let's change "-EINVAL" on "-ENOTSUPP" for legacy tracker init call in a
container and in case of this error code, try nfsdcld client tracker instead
of returning a error.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
---
 fs/nfsd/nfs4recover.c |   12 ++++++++----
 1 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index e0ae1cf..8aa069a 100644
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -524,7 +524,7 @@ nfsd4_legacy_tracking_init(struct net *net)
 	if (net != &init_net) {
 		WARN(1, KERN_ERR "NFSD: attempt to initialize legacy client "
 			"tracking in a container!\n");
-		return -EINVAL;
+		return -ENOTSUPP;
 	}
 
 	status = nfs4_legacy_state_init(net);
@@ -1285,14 +1285,17 @@ nfsd4_client_tracking_init(struct net *net)
 	/*
 	 * See if the recoverydir exists and is a directory. If it is,
 	 * then use the legacy ops.
+	 * If legacy ops init return -ENOSUPP, then we are in a container and
+	 * should try nfsdcld client tracking.
 	 */
 	nn->client_tracking_ops = &nfsd4_legacy_tracking_ops;
 	status = kern_path(nfs4_recoverydir(), LOOKUP_FOLLOW, &path);
 	if (!status) {
-		status = S_ISDIR(path.dentry->d_inode->i_mode);
+		if (S_ISDIR(path.dentry->d_inode->i_mode))
+			status = nn->client_tracking_ops->init(net);
 		path_put(&path);
-		if (status)
-			goto do_init;
+		if (status != -ENOTSUPP)
+			goto do_exit;
 	}
 
 	/* Finally, try to use nfsdcld */
@@ -1302,6 +1305,7 @@ nfsd4_client_tracking_init(struct net *net)
 			"nfsdcltrack.\n");
 do_init:
 	status = nn->client_tracking_ops->init(net);
+do_exit:
 	if (status) {
 		printk(KERN_WARNING "NFSD: Unable to initialize client "
 				    "recovery tracking! (%d)\n", status);