Used by userspace to detect DAX.
Signed-off-by: Adam Borowski <kilobyte@xxxxxxxxxx>
---
fs/btrfs/file.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 196c8f37ff9d..8efdb040bc1d 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -16,6 +16,7 @@
#include <linux/btrfs.h>
#include <linux/uio.h>
#include <linux/iversion.h>
+#include <linux/mman.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
@@ -3320,6 +3321,7 @@ const struct file_operations btrfs_file_operations = {
.splice_read = generic_file_splice_read,
.write_iter = btrfs_file_write_iter,
.mmap = btrfs_file_mmap,
+ .mmap_supported_flags = MAP_SYNC,
.open = btrfs_file_open,
.release = btrfs_release_file,
.fsync = btrfs_sync_file,
--
2.20.1
