Quite so :/ Even 'man 7 signal' says clearly that 'The details vary across Unix systems; below, the details for Linux', and that's not terribly useful really for the vast majority of software....
It seems you are right. http://www.opengroup.org/onlinepubs/9699919799/functions/... appears to allow any read to be interrupted, and says in the "informative" section "The issue of which f...
It's notable how many of those faults are *completely unchanged* from the days I was doing DOS, back in the DOS 3.3 days. MS really has strangled itself in the name of backward compatibility w...
I've heard this over and over again, but I've looked through the POSIX specs and I can't find it. No mention of slow reads, no mention that some devices are guaranteed not to get EINTR, no menti...
Great post! A little perspective can be nice at times.
Fair point, though that is really an NFS issue rather than a general Posix issue. And NFS has a lot more than just that to answer for. Posix has a concept of 'slow' and 'not slow' reads where ...
Sure, POSIX has flaws. But at least it's not Win32. When you're frustrated by POSIX, take a deep breath and say that three times. In the free world, there's no arbitrary 64-handle wait limit ....
You do get EINTR on read from a regular file if you're unlucky enough to have that file on a network device (e.g. NFS with intr turned on). And before you say 'don't do that then', before very r...
> Excellent idea - you've just described fallthru dentries. :) Yes.... after writing that I went back through the original article, noticed 'fallthru' this time, and felt a bit sheepish. I d...
Excellent idea - you've just described fallthru dentries. :) The implementation of fallthrus is pretty small, around a hundred lines in main VFS and then you reuse the whiteout infrastructure ...
?? You don't get EINTR on read from a regular file - only pipes, sockets, char devices and similar things. But in general I agree - signals make it very hard to write correct programs.
> It could be a nice long series - with lots of guest editors > probably. Hell yes. And the suck extends to fairly simple areas. Just saying 'EINTR' and 'short reads' is enough to ...
Yes, we need "Why POSIX made the Editor Grumpy". It could be a nice long series - with lots of guest editors probably. But telldir/seekdir isn't something that POSIX got wrong. Maybe the cooki...
> One of the great tragedies of the UNIX file system interface is the > enshrinement of readdir(), telldir(), seekdir(), etc. family in the > POSIX standard... I keep hea...
It works fine if you use unfs3 and probably also knfsd will partly work. In order to get knfsd properly working, we would need to switch to the low-level fuse interface (presently not on my TODO...
I know that performance needs to be increased and it is on my TODO list for the 2nd next version. However, you really have to compare how much time Radek and I spent on unionfs-fuse compared to ...
I believe unionfs-fuse has been tried for Debian and/or Ubuntu live-CDs and was found to be too slow to be usable. Currently they are both using aufs but they will probably switch to Val's imple...
Did unionfs-fuse work with NFS? Note: NFS needs seekdir()/telldir() to work, and that's the hard part. Last I heard, you couldn't NFS-export fuse filesystems (though that may well have changed n...
Somehow I find it amazing to spent so much time on the kernel implementation. In February 2007 I spent about 2 weeks on unionfs-fuse to add copy-on-write and it was then suitable for my needs....