fs: avoid inode RCU freeing for pseudo fs

Pseudo filesystems that don't put inode on RCU list or reachable by
rcu-walk dentries do not need to RCU free their inodes.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 1ff4d0a..ea202ff 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2233,6 +2233,7 @@
 extern void end_writeback(struct inode *);
 extern void __destroy_inode(struct inode *);
 extern struct inode *new_inode(struct super_block *);
+extern void free_inode_nonrcu(struct inode *inode);
 extern int should_remove_suid(struct dentry *);
 extern int file_remove_suid(struct file *);