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Subject: [PATCH 20/38] vfs: Convert nfsctl to fs_context
From:   David Howells <dhowells@redhat.com>
To:     viro@zeniv.linux.org.uk
Cc:     "J. Bruce Fields" <bfields@fieldses.org>,
        Jeff Layton <jlayton@kernel.org>, linux-nfs@vger.kernel.org,
        dhowells@redhat.com, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org
Date:   Thu, 14 Mar 2019 16:11:34 +0000
Message-ID: <155257989442.13720.9404403342947215402.stgit@warthog.procyon.org.uk>
In-Reply-To: <155257972443.13720.11743171471060355965.stgit@warthog.procyon.org.uk>
References: <155257972443.13720.11743171471060355965.stgit@warthog.procyon.org.uk>
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Signed-off-by: David Howells <dhowells@redhat.com>
cc: "J. Bruce Fields" <bfields@fieldses.org>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-nfs@vger.kernel.org
---

 fs/nfsd/nfsctl.c |   33 ++++++++++++++++++++++++++-------
 1 file changed, 26 insertions(+), 7 deletions(-)

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index f2feb2d11bae..d4eb4f34a94c 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -7,6 +7,7 @@
 #include <linux/slab.h>
 #include <linux/namei.h>
 #include <linux/ctype.h>
+#include <linux/fs_context.h>
 
 #include <linux/sunrpc/svcsock.h>
 #include <linux/lockd/lockd.h>
@@ -1146,7 +1147,7 @@ static ssize_t write_v4_end_grace(struct file *file, char *buf, size_t size)
  *	populating the filesystem.
  */
 
-static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
+static int nfsd_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	static const struct tree_descr nfsd_files[] = {
 		[NFSD_List] = {"exports", &exports_nfsd_operations, S_IRUGO},
@@ -1176,15 +1177,33 @@ static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
 #endif
 		/* last one */ {""}
 	};
-	get_net(sb->s_fs_info);
+
 	return simple_fill_super(sb, 0x6e667364, nfsd_files);
 }
 
-static struct dentry *nfsd_mount(struct file_system_type *fs_type,
-	int flags, const char *dev_name, void *data)
+static int nfsd_fs_get_tree(struct fs_context *fc)
+{
+	fc->s_fs_info = get_net(fc->net_ns);
+	return vfs_get_super(fc, vfs_get_keyed_super, nfsd_fill_super);
+}
+
+static void nfsd_fs_free_fc(struct fs_context *fc)
+{
+	if (fc->s_fs_info)
+		put_net(fc->s_fs_info);
+}
+
+static const struct fs_context_operations nfsd_fs_context_ops = {
+	.free		= nfsd_fs_free_fc,
+	.get_tree	= nfsd_fs_get_tree,
+};
+
+static int nfsd_init_fs_context(struct fs_context *fc)
 {
-	struct net *net = current->nsproxy->net_ns;
-	return mount_ns(fs_type, flags, data, net, net->user_ns, nfsd_fill_super);
+	put_user_ns(fc->user_ns);
+	fc->user_ns = get_user_ns(fc->net_ns->user_ns);
+	fc->ops = &nfsd_fs_context_ops;
+	return 0;
 }
 
 static void nfsd_umount(struct super_block *sb)
@@ -1198,7 +1217,7 @@ static void nfsd_umount(struct super_block *sb)
 static struct file_system_type nfsd_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "nfsd",
-	.mount		= nfsd_mount,
+	.init_fs_context = nfsd_init_fs_context,
 	.kill_sb	= nfsd_umount,
 };
 MODULE_ALIAS_FS("nfsd");