Re: files disappearing from ls on NFS

On Sun, 12 May 2013, Rick Macklem wrote:

RM>Hartmut Brandt wrote:
RM>> Hi,
RM>> 
RM>> I've updated one of my -current machines this week (previous update
RM>> was in
RM>> february). Now I see a strange effect (it seems only on NFS mounts):
RM>> ls or
RM>> even echo * will list only some files (strange enough the first files
RM>> from
RM>> the normal, alphabetically ordered list). If I change something in the
RM>> directory (delete a file or create a new one) for some time the
RM>> complete
RM>> listing will appear but after sime time (seconds to a minute or so)
RM>> again
RM>> only part of the files is listed.
RM>> 
RM>> A ktrace on ls /usr/src/lib/libc/gen shows that getdirentries is
RM>> called
RM>> only once (returning 4096). For a full listing getdirentries is called
RM>> 5
RM>> times with the last returning 0.
RM>> 
RM>> I can still open files that are not listed if I know their name,
RM>> though.
RM>> 
RM>> The NFS server is a Windows 2008 server with an OpenText NFS Server
RM>> which
RM>> works without problems to all the other FreeBSD machines.
RM>> 
RM>> So what could that be?
RM>> 
RM>I've attached a patch that might be worth trying. It is a "shot in the dark",
RM>but brings the new NFS client's readdir closer to the old one (which you
RM>mentioned still works ok).
RM>
RM>Please let me know how it goes, if you have a chance to test it, rick

Hi Rick,

the patch doesn't help.

I wrote a small test program, which opens a directory, calls getdents(2) 
in a loop and dumps that. I figured out, that the return of the system 
call depends on the buffer size I pass to it. The directory has a block 
size of 4k according to fstat(2). If I use that, I get some 300 of the 
almost 500 directory entries. If I use 8k, I get just around 200 and if I 
use 16k I get a handfull. If I dump the buffer in this case I see 0x200 
bytes filled with directory entries, then a lot of zeros and starting from 
0x1000 again data. This is of course ignored because of the zeros before.

All this looks very strange.

harti