On Wed, Oct 10, 2012 at 06:07:24PM +0800, zwu.kernel@xxxxxxxxx wrote: > +void hot_track_init(struct super_block *sb) > +{ ... > +} > +void hot_track_exit(struct super_block *sb) > +{ > + hot_cache_exit(); > +} Needs to be exported if btrfs is built as a module, otherwise does not link LDS arch/x86/boot/compressed/vmlinux.lds AS arch/x86/boot/compressed/head_64.o CC arch/x86/boot/compressed/misc.o CC arch/x86/boot/compressed/string.o CC arch/x86/boot/compressed/cmdline.o CC arch/x86/boot/compressed/early_serial_console.o OBJCOPY arch/x86/boot/compressed/vmlinux.bin ERROR: "hot_track_init" [fs/btrfs/btrfs.ko] undefined! ERROR: "hot_track_exit" [fs/btrfs/btrfs.ko] undefined! make[1]: *** [__modpost] Error 1 make: *** [modules] Error 2 make: *** Waiting for unfinished jobs.... david -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html