Jeff King <peff@xxxxxxxx> writes: > One brief aside: I'm still not entirely convinced that NonStop isn't > violating POSIX. Yes, as Eric noted, fsync() is allowed to return EINTR. > But should it do so when the signal it got was set up with SA_RESTART? > > The sigaction(3posix) page says: > > SA_RESTART This flag affects the behavior of interruptible functions; > that is, those specified to fail with errno set to > [EINTR]. If set, and a function specified as > interruptible is interrupted by this signal, the > function shall restart and shall not fail with [EINTR] > unless otherwise specified. [...] > > and I could not find anywhere that it is "otherwise specified" for > fsync(). Of course, whatever POSIX says, if NonStop needs this > workaround, we should provide it. But this may explain why we never saw > it on other systems. Yeah, I think all of the above makes sense. > It also means it's less important for this workaround to kick in > everywhere. But given how low-cost it is, I'm just as happy to avoid > having a separate knob to enable it. Yes, any caller who cares about the result of fsync() is willing to wait, and on a well benaved system, we would never see EINTR so the loop won't iterate. Having to carry just a handful of extra bytes in ICache in a codepath that is not performance critical is probably an acceptable cost for simpler code.
