NFS: Create a common xdev_mount() function

The only difference between nfs_xdev_mount() and nfs4_xdev_mount() is the
clone_super() function called to clone the super block.  I can combine
these two functions by using the fill_super field in the mount_info
structure.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 32 insertions, 90 deletions

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 64a62da6612d..707d1f67fb32 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -280,6 +280,7 @@ static match_table_t nfs_vers_tokens = {
 struct nfs_mount_info {
         void (*fill_super)(struct super_block *, struct nfs_mount_info *);
         struct nfs_parsed_mount_data *parsed;
+        struct nfs_clone_mount *cloned;
 };
 
 static void nfs_umount_begin(struct super_block *);
@@ -2160,8 +2161,9 @@ static void nfs_fill_super(struct super_block *sb,
  * Finish setting up a cloned NFS2/3 superblock
  */
 static void nfs_clone_super(struct super_block *sb,
-                            const struct super_block *old_sb)
+                            struct nfs_mount_info *mount_info)
 {
+        const struct super_block *old_sb = mount_info->cloned->sb;
         struct nfs_server *server = NFS_SB(sb);
 
         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
@@ -2454,13 +2456,13 @@ static void nfs_kill_super(struct super_block *s)
 }
 
 /*
- * Clone an NFS2/3 server record on xdev traversal (FSID-change)
+ * Clone an NFS2/3/4 server record on xdev traversal (FSID-change)
  */
 static struct dentry *
-nfs_xdev_mount(struct file_system_type *fs_type, int flags,
-                const char *dev_name, void *raw_data)
+nfs_xdev_mount_common(struct file_system_type *fs_type, int flags,
+                const char *dev_name, struct nfs_mount_info *mount_info)
 {
-        struct nfs_clone_mount *data = raw_data;
+        struct nfs_clone_mount *data = mount_info->cloned;
         struct super_block *s;
         struct nfs_server *server;
         struct dentry *mntroot;
@@ -2470,7 +2472,7 @@ nfs_xdev_mount(struct file_system_type *fs_type, int flags,
         };
         int error;
 
-        dprintk("--> nfs_xdev_mount()\n");
+        dprintk("--> nfs_xdev_mount_common()\n");
 
         /* create a new volume representation */
         server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr, data->authflavor);
@@ -2505,7 +2507,7 @@ nfs_xdev_mount(struct file_system_type *fs_type, int flags,
 
         if (!s->s_root) {
                 /* initial superblock/root creation */
-                nfs_clone_super(s, data->sb);
+                mount_info->fill_super(s, mount_info);
                 nfs_get_cache_cookie(s, NULL, data);
         }
 
@@ -2525,13 +2527,13 @@ nfs_xdev_mount(struct file_system_type *fs_type, int flags,
         /* clone any lsm security options from the parent to the new sb */
         security_sb_clone_mnt_opts(data->sb, s);
 
-        dprintk("<-- nfs_xdev_mount() = 0\n");
+        dprintk("<-- nfs_xdev_mount_common() = 0\n");
         return mntroot;
 
 out_err_nosb:
         nfs_free_server(server);
 out_err_noserver:
-        dprintk("<-- nfs_xdev_mount() = %d [error]\n", error);
+        dprintk("<-- nfs_xdev_mount_common() = %d [error]\n", error);
         return ERR_PTR(error);
 
 error_splat_super:
@@ -2539,18 +2541,33 @@ error_splat_super:
                 bdi_unregister(&server->backing_dev_info);
 error_splat_bdi:
         deactivate_locked_super(s);
-        dprintk("<-- nfs_xdev_mount() = %d [splat]\n", error);
+        dprintk("<-- nfs_xdev_mount_common() = %d [splat]\n", error);
         return ERR_PTR(error);
 }
 
+/*
+ * Clone an NFS2/3 server record on xdev traversal (FSID-change)
+ */
+static struct dentry *
+nfs_xdev_mount(struct file_system_type *fs_type, int flags,
+                const char *dev_name, void *raw_data)
+{
+        struct nfs_mount_info mount_info = {
+                .fill_super = nfs_clone_super,
+                .cloned   = raw_data,
+        };
+        return nfs_xdev_mount_common(&nfs_fs_type, flags, dev_name, &mount_info);
+}
+
 #ifdef CONFIG_NFS_V4
 
 /*
  * Finish setting up a cloned NFS4 superblock
  */
 static void nfs4_clone_super(struct super_block *sb,
-                            const struct super_block *old_sb)
+                             struct nfs_mount_info *mount_info)
 {
+        const struct super_block *old_sb = mount_info->cloned->sb;
         sb->s_blocksize_bits = old_sb->s_blocksize_bits;
         sb->s_blocksize = old_sb->s_blocksize;
         sb->s_maxbytes = old_sb->s_maxbytes;
@@ -2930,86 +2947,11 @@ static struct dentry *
 nfs4_xdev_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_server *server;
-        struct dentry *mntroot;
-        int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
-        struct nfs_sb_mountdata sb_mntdata = {
-                .mntflags = flags,
+        struct nfs_mount_info mount_info = {
+                .fill_super = nfs4_clone_super,
+                .cloned = raw_data,
         };
-        int error;
-
-        dprintk("--> nfs4_xdev_mount()\n");
-
-        /* create a new volume representation */
-        server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr, data->authflavor);
-        if (IS_ERR(server)) {
-                error = PTR_ERR(server);
-                goto out_err_noserver;
-        }
-        sb_mntdata.server = server;
-
-        if (server->flags & NFS_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_clone_super(s, data->sb);
-                nfs_get_cache_cookie(s, NULL, data);
-        }
-
-        mntroot = nfs_get_root(s, data->fh, 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;
-        }
-
-        s->s_flags |= MS_ACTIVE;
-
-        security_sb_clone_mnt_opts(data->sb, s);
-
-        dprintk("<-- nfs4_xdev_mount() = 0\n");
-        return mntroot;
-
-out_err_nosb:
-        nfs_free_server(server);
-out_err_noserver:
-        dprintk("<-- nfs4_xdev_mount() = %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);
-        dprintk("<-- nfs4_xdev_mount() = %d [splat]\n", error);
-        return ERR_PTR(error);
+        return nfs_xdev_mount_common(&nfs4_fs_type, flags, dev_name, &mount_info);
 }
 
 static struct dentry *