NFS4.1 Fix data server connection race
Unlike meta data server mounts which support multiple mount points to
the same server via struct nfs_server, data servers support a single connection.
Concurrent calls to setup the data server connection can race where the first
call allocates the nfs_client struct, and before the cache struct nfs_client
pointer can be set, a second call also tries to setup the connection, finds the
already allocated nfs_client, bumps the reference count, re-initializes the
session,etc. This results in a hanging data server session after umount.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4filelayout.h b/fs/nfs/nfs4filelayout.h
index b8da955..235ff95 100644
--- a/fs/nfs/nfs4filelayout.h
+++ b/fs/nfs/nfs4filelayout.h
@@ -70,6 +70,8 @@
struct list_head ds_addrs;
struct nfs_client *ds_clp;
atomic_t ds_count;
+ unsigned long ds_state;
+#define NFS4DS_CONNECTING 0 /* ds is establishing connection */
};
struct nfs4_file_layout_dsaddr {