My current interpretation of this problem is that it is some pathological condition caused by not rebalancing and being nearly out of space for allocating more metadata and hence it is rarely being seen by anyone else (because most users are regularly doing rebalances).
See this thread for details about rebalancing and out of space: "ENOSPC with mkdir and rename" on 2014-08-02: http://thread.gmane.org/gmane.comp.file-systems.btrfs/37415 I haven't had the lockups now since July and I'm now trialling a nightly rebalance: $ btrfs filesystem balance start -dusage=50 -musage=10 "$mount" I'll report back if I encounter further problems. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html