On Mon 29-04-19 12:26:43, Goldwyn Rodrigues wrote:
> From: Adam Borowski <kilobyte@xxxxxxxxxx>
>
> Used by userspace to detect DAX.
> [rgoldwyn@xxxxxxxx: Added CONFIG_FS_DAX around mmap_supported_flags]
Why the CONFIG_FS_DAX bit? Your mmap(2) implementation understands
implications of MAP_SYNC flag and that's all that's needed to set
.mmap_supported_flags.
Honza
> Signed-off-by: Adam Borowski <kilobyte@xxxxxxxxxx>
> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
> ---
> fs/btrfs/file.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
> index 9d5a3c99a6b9..362a9cf9dcb2 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"
> @@ -3319,6 +3320,9 @@ const struct file_operations btrfs_file_operations = {
> .splice_read = generic_file_splice_read,
> .write_iter = btrfs_file_write_iter,
> .mmap = btrfs_file_mmap,
> +#ifdef CONFIG_FS_DAX
> + .mmap_supported_flags = MAP_SYNC,
> +#endif
> .open = btrfs_file_open,
> .release = btrfs_release_file,
> .fsync = btrfs_sync_file,
> --
> 2.16.4
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
