[ccache] ccache: FATAL: Could not create xxx.o.tmp.stdout.yyy.zzz (permission denied?)

[Lalit Chhabra]

Hi,

 We have deployed ccache 3.1.7 (over NFS), with the cache being shared amongst about 30-40 people. The cache max size is configured to be 20G. We primarily compile c++ files with g++, each of which take less than a couple of minutes to compile. This has mostly been very sucessful, except that every once in a while, we get the above FATAL error from ccache. (I have seen this 2 times, in the past 4 months that we have been using ccache.)

 My initial guess was that there is some race condition between one users' ccache process doing a clean-up, while another users' compile is going on. But looking at the code, temp files have to be at least one hour old for them to get cleaned up.

 Another odd thing that I have seen (just once so far), is that the cache max size got reduced to 18.8G (which seems to be close to 20G*15/16). This caused a lot more of the "FATAL: Could not create..." messages to appear, until I reset the cache size back to 20G.

 I am not sure if both of these observations are related. Any ideas what could be going on?

 Thanks,
 Lalit Chhabra