block: use fallocate(FALLOC_FL_ZERO_RANGE) in handle_aiocb_write_zeroes
This efficiently writes zeroes on Linux if the kernel is capable enough.
FALLOC_FL_ZERO_RANGE correctly handles all cases, including and not
including file expansion.
CC: Kevin Wolf <kwolf@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Peter Lieven <pl@kamp.de>
CC: Fam Zheng <famz@redhat.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/configure b/configure
index f185dd0..e00e03a 100755
--- a/configure
+++ b/configure
@@ -3335,6 +3335,22 @@
fallocate_punch_hole=yes
fi
+# check that fallocate supports range zeroing inside the file
+fallocate_zero_range=no
+cat > $TMPC << EOF
+#include <fcntl.h>
+#include <linux/falloc.h>
+
+int main(void)
+{
+ fallocate(0, FALLOC_FL_ZERO_RANGE, 0, 0);
+ return 0;
+}
+EOF
+if compile_prog "" "" ; then
+ fallocate_zero_range=yes
+fi
+
# check for posix_fallocate
posix_fallocate=no
cat > $TMPC << EOF
@@ -4567,6 +4583,9 @@
if test "$fallocate_punch_hole" = "yes" ; then
echo "CONFIG_FALLOCATE_PUNCH_HOLE=y" >> $config_host_mak
fi
+if test "$fallocate_zero_range" = "yes" ; then
+ echo "CONFIG_FALLOCATE_ZERO_RANGE=y" >> $config_host_mak
+fi
if test "$posix_fallocate" = "yes" ; then
echo "CONFIG_POSIX_FALLOCATE=y" >> $config_host_mak
fi
