Not exactly sure what failure mode for reading you're trying to emulate. Are you checking with -r then if that succeeds doing the open? Because if so then that's introducing a possible race condition. In general it's better to do whatever open operation and deal with the failure than do a test and then take action (the former will be atomic; the latter opens a window something else can change the state of the filesystem under you).

That being said if that is what you're trying to emulate I want to say that I've seen weird access and permissions behavior when running as root on a filesystem with the squash root option on (then again I may be recalling something in Tcl where it was using the access(3) library routine which short circuited and always returned true for root).

The cake is a lie.
The cake is a lie.
The cake is a lie.

In reply to Re: Testing unexpected I/O failures by Fletch
in thread Testing unexpected I/O failures by kcott

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