Thanks for the bug report. I pushed the following patch to paxutils and it should propagate into GNU tar in the next release.
>From 63493234ec38ad606a5f726bc82e4fe5d8661cab Mon Sep 17 00:00:00 2001 From: Paul Eggert <egg...@cs.ucla.edu> Date: Mon, 28 Oct 2013 21:16:53 -0700 Subject: [PATCH] paxutils: support --sparse with tiny files on Netapp filers * lib/system.h (ST_IS_SPARSE): Port to NFS + Netapp filers, where a tiny file can have zero blocks but nonzero size. Problem reported by Andrew J. Schorr in <http://lists.gnu.org/archive/html/bug-tar/2013-10/msg00030.html>. --- lib/system.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/lib/system.h b/lib/system.h index ef46267..e7f531c 100644 --- a/lib/system.h +++ b/lib/system.h @@ -389,9 +389,16 @@ extern int errno; # define ST_NBLOCKSIZE 512 #endif +/* Network Appliance file systems store small files directly in the + inode if st_size <= 64; in this case the number of blocks can be + zero. Perhaps other file systems have similar problems; so, + somewhat arbitrarily, do not consider a file to be sparse if + it has no blocks but st_size < ST_NBLOCKSIZE. */ #define ST_IS_SPARSE(st) \ (ST_NBLOCKS (st) \ - < ((st).st_size / ST_NBLOCKSIZE + ((st).st_size % ST_NBLOCKSIZE != 0))) + < ((st).st_size / ST_NBLOCKSIZE \ + + ((st).st_size % ST_NBLOCKSIZE != 0 \ + && (st).st_size / ST_NBLOCKSIZE != 0))) /* Declare standard functions. */ -- 1.8.3.1
