On 21/08/2015 07:01, Colin Booth wrote:
Not a bug in s6-rc or s6 but in some Debian script somewhere. Some single-user script appears to re-mount all mount points, which has the net result of causing all file handles into tmpfs mounts to go stale.
Wow. Is it a "mount -o remount", or a umount followed by a mount ? If a -o remount has this effect on file handles, then it's probably worth reporting to the kernel guys, because it's insane. Even if the script does something nonsensical such as remounting everything read-only, which hardly makes any sense for a tmpfs, this is not normal behaviour: when I remount a partition in read-only mode, and there are still open descriptors for writing, the mount() call fails with EBUSY; it does not silently invalidate all the writing descriptors!
I am learning way more about the complexities of the distro boot cycle than I'd ever expected to this week.
Last time I looked at a mainstream distro's boot cycle, i.e. almost 10 years ago, it was already unnecessarily complex and convoluted; and Debian was far from the worst. I doubt it has become simpler since. systemd will probably make scripting simpler, by moving a lot of the complexity into the C code. Which is obviously the worst possible solution. -- Laurent
