Re: [PATCH 7/7] NFS: Use nfs_fs_mount_common() for remote referral mounts

["Myklebust, Trond" <Trond.Myklebust@xxxxxxxxxx>]

On Mon, 2012-04-30 at 14:40 -0400, bjschuma@xxxxxxxxxx wrote:
> From: Bryan Schumaker <bjschuma@xxxxxxxxxx>
> 
> Signed-off-by: Bryan Schumaker <bjschuma@xxxxxxxxxx>
> ---
>  fs/nfs/super.c |   90 +++++++++-----------------------------------------------
>  1 file changed, 14 insertions(+), 76 deletions(-)
> 
> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> index 9ed670b..21b229c 100644
> --- a/fs/nfs/super.c
> +++ b/fs/nfs/super.c
> @@ -2774,95 +2774,33 @@ static struct dentry *
>  nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
>  			   const char *dev_name, void *raw_data)
>  {
> -	struct nfs_clone_mount *data = raw_data;
> -	struct super_block *s;
> +	struct nfs_mount_info mount_info = {
> +		.fill_super = nfs4_fill_super,
> +		.set_security = nfs_clone_sb_security,
> +		.cloned = raw_data,
> +		.unshared = NFS4_MOUNT_UNSHARED,

This seems to be setting all referral mounts to NFS4_MOUNT_UNSHARED. Why
the change in behaviour?

> +	};
>  	struct nfs_server *server;
> -	struct dentry *mntroot;
> +	struct dentry *mntroot = ERR_PTR(-ENOMEM);
>  	struct nfs_fh *mntfh;
> -	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
> -	struct nfs_sb_mountdata sb_mntdata = {
> -		.mntflags = flags,
> -	};
> -	int error = -ENOMEM;
>  
>  	dprintk("--> nfs4_referral_get_sb()\n");
>  
>  	mntfh = nfs_alloc_fhandle();
> -	if (mntfh == NULL)
> -		goto out_err_nofh;
> +	if (mount_info.cloned == NULL || mntfh == NULL)
> +		goto out;
>  
>  	/* create a new volume representation */
> -	server = nfs4_create_referral_server(data, mntfh);
> +	server = nfs4_create_referral_server(mount_info.cloned, mntfh);
>  	if (IS_ERR(server)) {
> -		error = PTR_ERR(server);
> -		goto out_err_noserver;
> -	}
> -	sb_mntdata.server = server;
> -
> -	if (server->flags & NFS4_MOUNT_UNSHARED)
> -		compare_super = NULL;
> -
> -	/* -o noac implies -o sync */
> -	if (server->flags & NFS_MOUNT_NOAC)
> -		sb_mntdata.mntflags |= MS_SYNCHRONOUS;
> -
> -	/* Get a superblock - note that we may end up sharing one that already exists */
> -	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
> -	if (IS_ERR(s)) {
> -		error = PTR_ERR(s);
> -		goto out_err_nosb;
> -	}
> -
> -	if (s->s_fs_info != server) {
> -		nfs_free_server(server);
> -		server = NULL;
> -	} else {
> -		error = nfs_bdi_register(server);
> -		if (error)
> -			goto error_splat_bdi;
> -	}
> -
> -	if (!s->s_root) {
> -		/* initial superblock/root creation */
> -		nfs4_fill_super(s, NULL);
> -		nfs_fscache_get_super_cookie(s, NULL, data);
> -	}
> -
> -	mntroot = nfs_get_root(s, mntfh, dev_name);
> -	if (IS_ERR(mntroot)) {
> -		error = PTR_ERR(mntroot);
> -		goto error_splat_super;
> -	}
> -	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
> -		dput(mntroot);
> -		error = -ESTALE;
> -		goto error_splat_super;
> +		mntroot = ERR_CAST(server);
> +		goto out;
>  	}
>  
> -	s->s_flags |= MS_ACTIVE;
> -
> -	security_sb_clone_mnt_opts(data->sb, s);
> -
> +	mntroot = nfs_fs_mount_common(&nfs4_fs_type, server, flags, dev_name, mntfh, &mount_info);
> +out:
>  	nfs_free_fhandle(mntfh);
> -	dprintk("<-- nfs4_referral_get_sb() = 0\n");
>  	return mntroot;
> -
> -out_err_nosb:
> -	nfs_free_server(server);
> -out_err_noserver:
> -	nfs_free_fhandle(mntfh);
> -out_err_nofh:
> -	dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
> -	return ERR_PTR(error);
> -
> -error_splat_super:
> -	if (server && !s->s_root)
> -		bdi_unregister(&server->backing_dev_info);
> -error_splat_bdi:
> -	deactivate_locked_super(s);
> -	nfs_free_fhandle(mntfh);
> -	dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
> -	return ERR_PTR(error);
>  }
>  
>  /*

-- 
Trond Myklebust
Linux NFS client maintainer

NetApp
Trond.Myklebust@xxxxxxxxxx
www.netapp.com

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