btrfs-ino-cache is running on each reboot

[dima <dolenin@parallels.com>]

Hello all,

About a week or so ago I noticed that [btrfs-ino-cache] process was 
appearing in the 'top' on each reboot and disk is spinning like crazy 
for about five minutes or so. Quite so often this caused X failing to 
start because all I/O was busy with caching.
Even after letting it to calm down and seeing [btrfs-ino-cache] 
disappearing from the process list, on next reboot it starts all over again.

Here is the fstab entry that I have

UUID=430dca92-9541-4201-0f62-373e30beadac / btrfs 
subvol=root_subvolume,defaults,noatime,noacl,compress=lzo,inode_cache,space_cache,autodefrag 
0 0

inode_cache was always enabled since the FS was created about a year or 
so ago, and actually I have never had any problems with it up until 
recently.

Removing inode_cache option from fstab solves the problem, but I am not 
sure if it is the right choice.
I can observe the problem at least in the vanilla kernel 3.10.4 ~ 6 (did 
not try older versions)

What could be the reason for such behavior and how to avoid it?

thanks