tail,stat: improve support for ZFS

This change enables tail -f to use inotify and lets
stat -f --format=%T report the file system type name, "zfs".
* src/stat.c (human_fstype): Add a case: zfs, 0x2fc12fc1.
* NEWS (Improvements): Mention it.
* THANKS.in: Update.
Reported by Raimonds Miltins in http://bugs.gnu.org/12301.

NEWS

@@ -19,6 +19,13 @@ GNU coreutils NEWS                                    -*- outline -*-
   than ignoring the -d option and failing with an 'Is a directory' error.
   [bug introduced in coreutils-8.19, with the addition of --dir (-d)]
 
+** Improvements
+
+  stat and tail work better with ZFS.  stat -f --format=%T now reports the
+  file system type, "zfs", and tail -f now uses inotify for files on ZFS
+  file systems, rather than the default (for unknown file system types)
+  of polling.
+
 
 * Noteworthy changes in release 8.19 (2012-08-20) [stable]
 

THANKS.in

@@ -507,6 +507,7 @@ Piotr Kwapulinski                   kwap@univ.gda.pl
 Prashant TR                         tr@eth.net
 Priit Jõerüüt                       jemm4jemm@yahoo.com
 Primoz PETERLIN                     primozz.peterlin@gmail.com
+Raimonds Miltins                    raimonds@pro-9.com
 Rainer Orth                         ro@TechFak.Uni-Bielefeld.DE
 Ralf W. Stephan                     stephan@tmt.de
 Ralph Loader                        loader@maths.ox.ac.uk

src/stat.c

@@ -423,6 +423,8 @@ human_fstype (STRUCT_STATVFS const *statfsbuf)
       return "xfs";
     case S_MAGIC_XIAFS: /* 0x012FD16D local */
       return "xia";
+    case S_MAGIC_ZFS: /* 0x2FC12FC1 local */
+      return "zfs";
 
 # elif __GNU__
     case FSTYPE_UFS: