* Josef Bacik:
As for your ENOSPC issue, I've made improvements on that area.
I
see this in production as well, I have monitoring in place to deal
with the machine before it gets to this point. That being said if
you run the box out of metadata space things get tricky to fix.
I've been working my way down the list of issues in this area for
years, this last go around of patches I sent were in these corner
cases.
Is there anything we need to do in userspace to improve the behavior
of fflush and similar interfaces?
This is not strictly a btrfs issue: Some of us are worried about
scenarios where the write system call succeeds and the data never
makes it to storage *without a catastrophic failure*. (I do not
consider running out of disk space a catastrophic failure.) NFS
apparently has this property, and you have to call fsync or close the
descriptor to detect this. fsync is not desirable due to its
performance impact.