Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 164 insertions, 0 deletions

diff --git a/fs/nfs/getroot.c b/fs/nfs/getroot.c
new file mode 100644
index 000000000..11ff2b2e0
--- /dev/null
+++ b/fs/nfs/getroot.c
@@ -0,0 +1,164 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* getroot.c: get the root dentry for an NFS mount
+ *
+ * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+
+#include <linux/time.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/stat.h>
+#include <linux/errno.h>
+#include <linux/unistd.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/stats.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_mount.h>
+#include <linux/lockd/bind.h>
+#include <linux/seq_file.h>
+#include <linux/mount.h>
+#include <linux/vfs.h>
+#include <linux/namei.h>
+#include <linux/security.h>
+
+#include <linux/uaccess.h>
+
+#include "internal.h"
+
+#define NFSDBG_FACILITY		NFSDBG_CLIENT
+
+/*
+ * Set the superblock root dentry.
+ * Note that this function frees the inode in case of error.
+ */
+static int nfs_superblock_set_dummy_root(struct super_block *sb, struct inode *inode)
+{
+	/* The mntroot acts as the dummy root dentry for this superblock */
+	if (sb->s_root == NULL) {
+		sb->s_root = d_make_root(inode);
+		if (sb->s_root == NULL)
+			return -ENOMEM;
+		ihold(inode);
+		/*
+		 * Ensure that this dentry is invisible to d_find_alias().
+		 * Otherwise, it may be spliced into the tree by
+		 * d_splice_alias if a parent directory from the same
+		 * filesystem gets mounted at a later time.
+		 * This again causes shrink_dcache_for_umount_subtree() to
+		 * Oops, since the test for IS_ROOT() will fail.
+		 */
+		spin_lock(&d_inode(sb->s_root)->i_lock);
+		spin_lock(&sb->s_root->d_lock);
+		hlist_del_init(&sb->s_root->d_u.d_alias);
+		spin_unlock(&sb->s_root->d_lock);
+		spin_unlock(&d_inode(sb->s_root)->i_lock);
+	}
+	return 0;
+}
+
+/*
+ * get an NFS2/NFS3 root dentry from the root filehandle
+ */
+int nfs_get_root(struct super_block *s, struct fs_context *fc)
+{
+	struct nfs_fs_context *ctx = nfs_fc2context(fc);
+	struct nfs_server *server = NFS_SB(s), *clone_server;
+	struct nfs_fsinfo fsinfo;
+	struct dentry *root;
+	struct inode *inode;
+	char *name;
+	int error = -ENOMEM;
+	unsigned long kflags = 0, kflags_out = 0;
+
+	name = kstrdup(fc->source, GFP_KERNEL);
+	if (!name)
+		goto out;
+
+	/* get the actual root for this mount */
+	fsinfo.fattr = nfs_alloc_fattr_with_label(server);
+	if (fsinfo.fattr == NULL)
+		goto out_name;
+
+	error = server->nfs_client->rpc_ops->getroot(server, ctx->mntfh, &fsinfo);
+	if (error < 0) {
+		dprintk("nfs_get_root: getattr error = %d\n", -error);
+		nfs_errorf(fc, "NFS: Couldn't getattr on root");
+		goto out_fattr;
+	}
+
+	inode = nfs_fhget(s, ctx->mntfh, fsinfo.fattr);
+	if (IS_ERR(inode)) {
+		dprintk("nfs_get_root: get root inode failed\n");
+		error = PTR_ERR(inode);
+		nfs_errorf(fc, "NFS: Couldn't get root inode");
+		goto out_fattr;
+	}
+
+	error = nfs_superblock_set_dummy_root(s, inode);
+	if (error != 0)
+		goto out_fattr;
+
+	/* root dentries normally start off anonymous and get spliced in later
+	 * if the dentry tree reaches them; however if the dentry already
+	 * exists, we'll pick it up at this point and use it as the root
+	 */
+	root = d_obtain_root(inode);
+	if (IS_ERR(root)) {
+		dprintk("nfs_get_root: get root dentry failed\n");
+		error = PTR_ERR(root);
+		nfs_errorf(fc, "NFS: Couldn't get root dentry");
+		goto out_fattr;
+	}
+
+	security_d_instantiate(root, inode);
+	spin_lock(&root->d_lock);
+	if (IS_ROOT(root) && !root->d_fsdata &&
+	    !(root->d_flags & DCACHE_NFSFS_RENAMED)) {
+		root->d_fsdata = name;
+		name = NULL;
+	}
+	spin_unlock(&root->d_lock);
+	fc->root = root;
+	if (server->caps & NFS_CAP_SECURITY_LABEL)
+		kflags |= SECURITY_LSM_NATIVE_LABELS;
+	if (ctx->clone_data.sb) {
+		if (d_inode(fc->root)->i_fop != &nfs_dir_operations) {
+			error = -ESTALE;
+			goto error_splat_root;
+		}
+		/* clone lsm security options from the parent to the new sb */
+		error = security_sb_clone_mnt_opts(ctx->clone_data.sb,
+						   s, kflags, &kflags_out);
+		if (error)
+			goto error_splat_root;
+		clone_server = NFS_SB(ctx->clone_data.sb);
+		server->has_sec_mnt_opts = clone_server->has_sec_mnt_opts;
+	} else {
+		error = security_sb_set_mnt_opts(s, fc->security,
+							kflags, &kflags_out);
+	}
+	if (error)
+		goto error_splat_root;
+	if (server->caps & NFS_CAP_SECURITY_LABEL &&
+		!(kflags_out & SECURITY_LSM_NATIVE_LABELS))
+		server->caps &= ~NFS_CAP_SECURITY_LABEL;
+
+	nfs_setsecurity(inode, fsinfo.fattr);
+	error = 0;
+
+out_fattr:
+	nfs_free_fattr(fsinfo.fattr);
+out_name:
+	kfree(name);
+out:
+	return error;
+error_splat_root:
+	dput(fc->root);
+	fc->root = NULL;
+	goto out_fattr;
+}