Problem writing sparse files over NFS to xfs filesystem

[Craig Tierney <ctierney@xxxxxxxx>]

I am having a problem with exporting xfs over
NFS. I have two servers that are exhibiting the
same problem where a piece of code writing a sparse
file gives the wrong filesize.

x86, smp, linux-2.4.5, Trond's NFS patches, 
    and linux-2.4.5-xfs-06112001.patch
alpha, uniprocessor, linux-2.4.6, Trond's NFS patches,
    and linux-2.4.6-xfs-07052001.patch

Both boxes are mounting luns from a fiber channel
storage device (both use Qlogic 2200, v4.27beta driver).

The filesystems on the x86 are lvm partitions (both
xfs and ext2, striped).  The filesystem on the alpha is not
lvm.

The size of the file written by the code below should be 40500 bytes.  
When this code is run on a xfs exported nfs filesystem, the filesize  
is 40960. This happens to both x86 and alpha NFS fileservers
over NFSv3 (udp packets, rsize=wsize=8192).  The code
runs correctly when run on the xfs filesystem directly.  The code
run correctly to a ext2 exported nfs filesystem on the x86 box.


/*********************/
#include <stdlib.h>
#include <stdio.h>
  
main (int argc, char **argv)
 {
 int x[588];
 long sA;
 FILE *f;
 int i;
#define ByteCount 2352
#define SeekIncr  (long) 3468
 sA = 0;
 f = fopen ("test40500", "w");
 sA = 0;
  
 for (i=0; i < 12; i++)
  {
  (void) fseek (f, sA, SEEK_SET);
  (void) fwrite (x, (size_t) ByteCount, (size_t) 1, f);
  sA += (SeekIncr);
  }
 (void) fclose(f);
 exit(0);
 }
/**************************/

Thanks,
Craig

-- 
Craig Tierney (ctierney@xxxxxxxx)
phone: 303-497-3112