nfs42: add NFS_IOC_CLONE_RANGE ioctl

It follows btrfs BTRFS_IOC_CLONE_RANGE lead on ioctl number and
arguments.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

2 files changed, 22 insertions, 1 deletions

diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
index 4f463dd8bae3..4384a1d00ceb 100644
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -288,14 +288,28 @@ out_drop_write:
         mnt_drop_write_file(dst_file);
         return ret;
 }
+
+static long nfs42_ioctl_clone_range(struct file *dst_file, void __user *argp)
+{
+        struct nfs_ioctl_clone_range_args args;
+
+        if (copy_from_user(&args, argp, sizeof(args)))
+                return -EFAULT;
+
+        return nfs42_ioctl_clone(dst_file, args.src_fd, args.src_off, args.dst_off, args.count);
+}
 #endif /* CONFIG_NFS_V4_2 */
 
 long nfs4_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
+        void __user *argp = (void __user *)arg;
+
         switch (cmd) {
 #ifdef CONFIG_NFS_V4_2
         case NFS_IOC_CLONE:
                 return nfs42_ioctl_clone(file, arg, 0, 0, 0);
+        case NFS_IOC_CLONE_RANGE:
+                return nfs42_ioctl_clone_range(file, argp);
 #endif
         }
 
diff --git a/include/uapi/linux/nfs.h b/include/uapi/linux/nfs.h
index d85748d3564d..c6b86cc404f8 100644
--- a/include/uapi/linux/nfs.h
+++ b/include/uapi/linux/nfs.h
@@ -33,7 +33,14 @@
 
 /* NFS ioctls */
 /* Let's follow btrfs lead on CLONE to avoid messing userspace */
-#define NFS_IOC_CLONE   _IOW(0x94, 9, int)
+#define NFS_IOC_CLONE           _IOW(0x94, 9, int)
+#define NFS_IOC_CLONE_RANGE     _IOW(0x94, 13, int)
+
+struct nfs_ioctl_clone_range_args {
+        __s64 src_fd;
+        __u64 src_off, count;
+        __u64 dst_off;
+};
 
 /*
  * NFS stats. The good thing with these values is that NFSv3 errors are