Re: Fwd: Re: A new look at old NFS readdir() problems?

Peter Eisentraut <peter@eisentraut.org> writes:
> On 03.01.25 02:58, Tom Lane wrote:
>> I poked at this a little further.  I made the attached stand-alone
>> test case (you don't need any more than "cc -o rmtree rmtree.c"
>> to build it, then point the script at some NFS-mounted directory).
>> This fails with my NAS at least as far back as FreeBSD 11.0.
>> I also tried it on NetBSD 9.2 which seems fine.

> If you use some GUI file manager, point at a directory, and select 
> "remove this directory with everything in it", what does it do 
> internally?  Surely it runs a readdir() loop and unlinks the files as it 
> gets to them?  Or does it indeed slurp the whole directory tree into 
> memory before starting the deletion?

One thing I noticed while testing yesterday is that "rm -rf foo"
worked even in cases where "rmtree foo" didn't.  I did not look
into FreeBSD's rm code, but I'll bet it has the sort of retry
logic that was recommended to us upthread.  I agree with your
point though that it's hard to believe that everyone does that
in every case where it would matter.

As for pre-existing bug reports, I found

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=57696

but there's basically no new information there, other than
the not-so-surprising fact that renaming directory entries
triggers the failure as efficiently as unlinking does.

            regards, tom lane