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authorDenis V. Lunev <den@openvz.org>2015-01-30 11:42:14 +0300
committerKevin Wolf <kwolf@redhat.com>2015-02-06 17:24:20 +0100
commitb953f075007a7860adce9fa410b2e116a3d5e29c (patch)
treea74183d720dfb65c01b65fc9acd93c9939f11f2e
parent37cc9f7f684ed035da63274daca1594c7ee16213 (diff)
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>
-rw-r--r--block/raw-posix.c15
-rwxr-xr-xconfigure19
2 files changed, 32 insertions, 2 deletions
diff --git a/block/raw-posix.c b/block/raw-posix.c
index d3910fdbf3..5a777e7137 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -60,7 +60,7 @@
#define FS_NOCOW_FL 0x00800000 /* Do not cow file */
#endif
#endif
-#ifdef CONFIG_FALLOCATE_PUNCH_HOLE
+#if defined(CONFIG_FALLOCATE_PUNCH_HOLE) || defined(CONFIG_FALLOCATE_ZERO_RANGE)
#include <linux/falloc.h>
#endif
#if defined (__FreeBSD__) || defined(__FreeBSD_kernel__)
@@ -902,7 +902,7 @@ static int translate_err(int err)
return err;
}
-#if defined(CONFIG_FALLOCATE_PUNCH_HOLE)
+#if defined(CONFIG_FALLOCATE_PUNCH_HOLE) || defined(CONFIG_FALLOCATE_ZERO_RANGE)
static int do_fallocate(int fd, int mode, off_t offset, off_t len)
{
do {
@@ -954,6 +954,17 @@ static ssize_t handle_aiocb_write_zeroes(RawPosixAIOData *aiocb)
}
#endif
+#ifdef CONFIG_FALLOCATE_ZERO_RANGE
+ if (s->has_write_zeroes) {
+ int ret = do_fallocate(s->fd, FALLOC_FL_ZERO_RANGE,
+ aiocb->aio_offset, aiocb->aio_nbytes);
+ if (ret == 0 || ret != -ENOTSUP) {
+ return ret;
+ }
+ s->has_write_zeroes = false;
+ }
+#endif
+
return -ENOTSUP;
}
diff --git a/configure b/configure
index f185dd0838..e00e03af32 100755
--- a/configure
+++ b/configure
@@ -3335,6 +3335,22 @@ if compile_prog "" "" ; then
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 > $TMPC << EOF
@@ -4567,6 +4583,9 @@ fi
if test "$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