Re: NFS locking bug -- limited mtime resolution means nfs_lock() does not provide coherency guarantee

From: Trond Myklebust (trond.myklebust@fys.uio.no)
Date: Wed Sep 13 2000 - 05:42:15 EST


>>>>> " " == Andi Kleen <ak@suse.de> writes:

> On Tue, Sep 12, 2000 at 09:10:56PM +0200, Trond Myklebust
> wrote:
>> Making mtime a true 64-bit cookie on Linux servers would be a
>> solution that works on all clients.

> Making mtime 64bit would also be useful for local parallel make
> runs, the current second resolution leads to race conditions on
> bigger SMP boxes.

> Unfortunately the only FS that supports <s on disk timestamps
> currently is XFS afaik, and there is no VFS interface for it.

You'd have to fix make as well: 'stat' & friends alway return the
timestamp in seconds.

Is there any 'standard' function for reading the microseconds fields
in userland? I couldn't find anything with a brief search in the
X/Open docs.

Cheers,
  Trond
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