Recent changes (master)

index 81244064..41b959d1 100644
@@ -1998,6 +1998,8 @@ I/O engine
 			requests for IME. FIO will then decide when to commit these requests.
 		**libiscsi**
 			Read and write iscsi lun with libiscsi.
+		**nbd**
+			Read and write a Network Block Device (NBD).
 
 I/O engine specific parameters
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

@@ -2299,6 +2301,15 @@ with the caveat that when used on the command line, they must come after the
 	turns on verbose logging from libcurl, 2 additionally enables
 	HTTP IO tracing. Default is **0**
 
+.. option:: uri=str : [nbd]
+
+	Specify the NBD URI of the server to test.  The string
+	is a standard NBD URI
+	(see https://github.com/NetworkBlockDevice/nbd/tree/master/doc).
+	Example URIs: nbd://localhost:10809
+	nbd+unix:///?socket=/tmp/socket
+	nbds://tlshost/exportname
+
 I/O depth
 ~~~~~~~~~
 

index d7e5fca7..fe02bf1d 100644
@@ -65,6 +65,12 @@ ifdef CONFIG_LIBISCSI
   SOURCE += engines/libiscsi.c
 endif
 
+ifdef CONFIG_LIBNBD
+  CFLAGS += $(LIBNBD_CFLAGS)
+  LIBS += $(LIBNBD_LIBS)
+  SOURCE += engines/nbd.c
+endif
+
 ifdef CONFIG_64BIT
   CFLAGS += -DBITS_PER_LONG=64
 endif

index a0692d58..b11b2dce 100755
@@ -149,6 +149,7 @@ disable_pmem="no"
 disable_native="no"
 march_set="no"
 libiscsi="no"
+libnbd="no"
 prefix=/usr/local
 
 # parse options

@@ -207,6 +208,8 @@ for opt do
   ;;
   --enable-libiscsi) libiscsi="yes"
   ;;
+  --enable-libnbd) libnbd="yes"
+  ;;
   --disable-tcmalloc) disable_tcmalloc="yes"
   ;;
   --help)

@@ -245,6 +248,7 @@ if test "$show_help" = "yes" ; then
   echo "--disable-native        Don't build for native host"
   echo "--with-ime=             Install path for DDN's Infinite Memory Engine"
   echo "--enable-libiscsi       Enable iscsi support"
+  echo "--enable-libnbd         Enable libnbd (NBD engine) support"
   echo "--disable-tcmalloc	Disable tcmalloc support"
   exit $exit_val
 fi

@@ -2014,6 +2018,23 @@ if test "$libiscsi" = "yes" ; then
 fi
 print_config "iscsi engine" "$libiscsi"
 
+##########################################
+# Check if we have libnbd (for NBD support).
+minimum_libnbd=0.9.6
+if test "$libnbd" = "yes" ; then
+  if $(pkg-config --atleast-version=$minimum_libnbd libnbd); then
+    libnbd="yes"
+    libnbd_cflags=$(pkg-config --cflags libnbd)
+    libnbd_libs=$(pkg-config --libs libnbd)
+  else
+    if test "$libnbd" = "yes" ; then
+      echo "libnbd" "Install libnbd >= $minimum_libnbd"
+    fi
+    libnbd="no"
+  fi
+fi
+print_config "NBD engine" "$libnbd"
+
 ##########################################
 # Check if we have lex/yacc available
 yacc="no"

@@ -2698,6 +2719,12 @@ if test "$libiscsi" = "yes" ; then
   echo "LIBISCSI_CFLAGS=$libiscsi_cflags" >> $config_host_mak
   echo "LIBISCSI_LIBS=$libiscsi_libs" >> $config_host_mak
 fi
+if test "$libnbd" = "yes" ; then
+  output_sym "CONFIG_LIBNBD"
+  echo "CONFIG_LIBNBD=m" >> $config_host_mak
+  echo "LIBNBD_CFLAGS=$libnbd_cflags" >> $config_host_mak
+  echo "LIBNBD_LIBS=$libnbd_libs" >> $config_host_mak
+fi
 cat > $TMPC << EOF
 int main(int argc, char **argv)
 {

new file mode 100644
index 00000000..27e15086
@@ -0,0 +1,35 @@
+# To use fio to test nbdkit:
+#
+# nbdkit -U - memory size=256M --run 'export unixsocket; fio examples/nbd.fio'
+#
+# To use fio to test qemu-nbd:
+#
+# rm -f /tmp/disk.img /tmp/socket
+# truncate -s 256M /tmp/disk.img
+# export unixsocket=/tmp/socket
+# qemu-nbd -t -k $unixsocket -f raw /tmp/disk.img &
+# fio examples/nbd.fio
+# killall qemu-nbd
+
+[global]
+ioengine=nbd
+uri=nbd+unix:///?socket=${unixsocket}
+# Starting from nbdkit 1.14 the following will work:
+#uri=${uri}
+rw=randrw
+time_based
+runtime=60
+group_reporting
+iodepth=64
+
+[job0]
+offset=0
+
+[job1]
+offset=064m
+
+[job2]
+offset=128m
+
+[job3]
+offset=192m

index 2966d9d5..97371d77 100644
@@ -1756,6 +1756,9 @@ FIO will then decide when to commit these requests.
 .TP
 .B libiscsi
 Read and write iscsi lun with libiscsi.
+.TP
+.B nbd
+Synchronous read and write a Network Block Device (NBD).
 .SS "I/O engine specific parameters"
 In addition, there are some parameters which are only valid when a specific
 \fBioengine\fR is in use. These are used identically to normal parameters,

@@ -2019,6 +2022,22 @@ blocksize=8k will write 16 sectors with each command. fio will still
 generate 8k of data for each command butonly the first 512 bytes will
 be used and transferred to the device. The writefua option is ignored
 with this selection.
+.RE
+.RE
+.TP
+.BI (nbd)uri \fR=\fPstr
+Specify the NBD URI of the server to test.
+The string is a standard NBD URI (see
+\fIhttps://github.com/NetworkBlockDevice/nbd/tree/master/doc\fR).
+Example URIs:
+.RS
+.RS
+.TP
+\fInbd://localhost:10809\fR
+.TP
+\fInbd+unix:///?socket=/tmp/socket\fR
+.TP
+\fInbds://tlshost/exportname\fR
 
 .SS "I/O depth"
 .TP