Messages in this thread | | | Date | Tue, 9 Sep 2014 12:18:21 -0400 | From | "J. Bruce Fields" <> | Subject | Re: [PATCH] locks: Ability to test for flock presence on fd |
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On Tue, Sep 02, 2014 at 11:07:14PM +0400, Pavel Emelyanov wrote: > > Would it make sense to return the lock type held instead, so you could > > do one flock(fd, LOCK_TEST) instead of flock(fd, LOCK_TEST|LOCK_SH) and > > flock(fd, LOCK_TEST|LOCK_EX) ? > > Well, in our case we parse /proc/locks anyway to see what > files at least to test for being locked. But what you propose > looks even better. I'll look what can be done here.
Actually I think I prefer your version. It seems cleaner to define LOCK_TEST as returning the same result as you'd get if you actually tried the lock, just without applying the lock. It avoids having a different return-value convention for this one command. It might avoid some ambiguity in cases where the flock might be denied for reasons other than a conflicting flock (e.g. on NFS where flocks and fcntl locks conflict). It's closer to what GETLK does in the fcntl case.
--b.
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