NFS: Add a super_block backpointer to the nfs_server struct

NFS_SB() returns the pointer to an nfs_server struct, given a
pointer to a super_block.  But we have no way to go back the other
way.

Add a super_block backpointer field so that, given an nfs_server
struct, it is easy to get to the filesystem's root dentry.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

2 files changed, 2 insertions, 0 deletions

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 3f5a7a85c9c2..e26647be69ce 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -2534,6 +2534,7 @@ struct dentry *nfs_fs_mount_common(struct nfs_server *server,
                         mntroot = ERR_PTR(error);
                         goto error_splat_bdi;
                 }
+                server->super = s;
         }
 
         if (!s->s_root) {
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index f9c0a6cb41e9..46b0cb4bee09 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -148,6 +148,7 @@ struct nfs_server {
         __u64                   maxfilesize;    /* maximum file size */
         struct timespec         time_delta;     /* smallest time granularity */
         unsigned long           mount_time;     /* when this fs was mounted */
+        struct super_block      *super;         /* VFS super block */
         dev_t                   s_dev;          /* superblock dev numbers */
 
 #ifdef CONFIG_NFS_FSCACHE