vfs: Allocate anon_inode_inode in anon_inode_init()

Currently we allocated anon_inode_inode in anon_inodefs_mount. This is
somewhat fragile as if that function ever gets called again, it will
overwrite anon_inode_inode pointer. So move the initialization of
anon_inode_inode to anon_inode_init().

Signed-off-by: Jan Kara <jack@suse.cz>
[ Further simplified on suggestion from Dave Jones ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 22 deletions

diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c
index 42fcc46e2cca..80ef38c73e5a 100644
--- a/fs/anon_inodes.c
+++ b/fs/anon_inodes.c
@@ -41,19 +41,8 @@ static const struct dentry_operations anon_inodefs_dentry_operations = {
 static struct dentry *anon_inodefs_mount(struct file_system_type *fs_type,
                                 int flags, const char *dev_name, void *data)
 {
-        struct dentry *root;
-        root = mount_pseudo(fs_type, "anon_inode:", NULL,
+        return mount_pseudo(fs_type, "anon_inode:", NULL,
                         &anon_inodefs_dentry_operations, ANON_INODE_FS_MAGIC);
-        if (!IS_ERR(root)) {
-                struct super_block *s = root->d_sb;
-                anon_inode_inode = alloc_anon_inode(s);
-                if (IS_ERR(anon_inode_inode)) {
-                        dput(root);
-                        deactivate_locked_super(s);
-                        root = ERR_CAST(anon_inode_inode);
-                }
-        }
-        return root;
 }
 
 static struct file_system_type anon_inode_fs_type = {
@@ -175,18 +164,15 @@ EXPORT_SYMBOL_GPL(anon_inode_getfd);
 
 static int __init anon_inode_init(void)
 {
-        int error;
-
         anon_inode_mnt = kern_mount(&anon_inode_fs_type);
-        if (IS_ERR(anon_inode_mnt)) {
-                error = PTR_ERR(anon_inode_mnt);
-                goto err_unregister_filesystem;
-        }
-        return 0;
+        if (IS_ERR(anon_inode_mnt))
+                panic("anon_inode_init() kernel mount failed (%ld)\n", PTR_ERR(anon_inode_mnt));
 
-err_unregister_filesystem:
-        unregister_filesystem(&anon_inode_fs_type);
-        panic(KERN_ERR "anon_inode_init() failed (%d)\n", error);
+        anon_inode_inode = alloc_anon_inode(anon_inode_mnt->mnt_sb);
+        if (IS_ERR(anon_inode_inode))
+                panic("anon_inode_init() inode allocation failed (%ld)\n", PTR_ERR(anon_inode_inode));
+
+        return 0;
 }
 
 fs_initcall(anon_inode_init);