On Wed, Oct 11, 2017 at 1:06 PM, Jan Kara <jack@xxxxxxx> wrote:
> Now when everything is prepared, add support in xfs to accept MAP_SYNC
> as an mmap(2) flag.
>
> Signed-off-by: Jan Kara <jack@xxxxxxx>
> ---
> fs/ext4/file.c | 1 +
> fs/xfs/xfs_file.c | 23 +++++++++++++++++++++++
> 2 files changed, 24 insertions(+)
>
> diff --git a/fs/ext4/file.c b/fs/ext4/file.c
> index f013cda84b3d..6b597cc6b29d 100644
> --- a/fs/ext4/file.c
> +++ b/fs/ext4/file.c
> @@ -26,6 +26,7 @@
> #include <linux/quotaops.h>
> #include <linux/pagevec.h>
> #include <linux/uio.h>
> +#include <linux/mman.h>
> #include "ext4.h"
> #include "ext4_jbd2.h"
> #include "xattr.h"
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index c45f24ffab22..fb135224476d 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -44,6 +44,7 @@
> #include <linux/falloc.h>
> #include <linux/pagevec.h>
> #include <linux/backing-dev.h>
> +#include <linux/mman.h>
>
> static const struct vm_operations_struct xfs_file_vm_ops;
>
> @@ -1142,6 +1143,27 @@ xfs_file_mmap(
> return 0;
> }
>
> +#define XFS_MAP_SUPPORTED (LEGACY_MAP_MASK | MAP_SYNC)
> +
> +static int
> +xfs_file_mmap_validate(
> + struct file *filp,
> + struct vm_area_struct *vma,
> + unsigned long map_flags)
> +{
> + if (map_flags & ~XFS_MAP_SUPPORTED)
> + return -EOPNOTSUPP;
> +
> + /*
> + * We don't support synchronous mappings for non-DAX files. At least
> + * until someone comes with a sensible use case.
> + */
> + if (!IS_DAX(file_inode(filp)) && (map_flags & MAP_SYNC))
> + return -EOPNOTSUPP;
Same comment about using EPERM here. That's also what I'm returning in
the MAP_DIRECT case when the inode is a reflink inode and does not
support MAP_DIRECT.
