btrfs: rename flags for vol args v2

Rename BTRFS_DEVICE_BY_ID so it's more descriptive that we specify the
device by id, it'll be part of the public API. The mask of supported
flags is also renamed, only for internal use.

The error code for unknown flags is EOPNOTSUPP, fixed.
Reviewed-by: NAnand Jain <anand.jain@oracle.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/ioctl.c

@@ -2687,8 +2687,8 @@ static long btrfs_ioctl_rm_dev_v2(struct file *file, void __user *arg)
 	}
 
 	/* Check for compatibility reject unknown flags */
-	if (vol_args->flags & ~BTRFS_VOL_ARG_V2_FLAGS)
-		return -ENOTTY;
+	if (vol_args->flags & ~BTRFS_VOL_ARG_V2_FLAGS_SUPPORTED)
+		return -EOPNOTSUPP;
 
 	if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running,
 			1)) {
@@ -2697,7 +2697,7 @@ static long btrfs_ioctl_rm_dev_v2(struct file *file, void __user *arg)
 	}
 
 	mutex_lock(&root->fs_info->volume_mutex);
-	if (vol_args->flags & BTRFS_DEVICE_BY_ID) {
+	if (vol_args->flags & BTRFS_DEVICE_SPEC_BY_ID) {
 		ret = btrfs_rm_device(root, NULL, vol_args->devid);
 	} else {
 		vol_args->name[BTRFS_SUBVOL_NAME_MAX] = '\0';
@@ -2707,7 +2707,7 @@ static long btrfs_ioctl_rm_dev_v2(struct file *file, void __user *arg)
 	atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0);
 
 	if (!ret) {
-		if (vol_args->flags & BTRFS_DEVICE_BY_ID)
+		if (vol_args->flags & BTRFS_DEVICE_SPEC_BY_ID)
 			btrfs_info(root->fs_info, "device deleted: id %llu",
 					vol_args->devid);
 		else

include/uapi/linux/btrfs.h

@@ -36,12 +36,13 @@ struct btrfs_ioctl_vol_args {
 #define BTRFS_SUBVOL_CREATE_ASYNC	(1ULL << 0)
 #define BTRFS_SUBVOL_RDONLY		(1ULL << 1)
 #define BTRFS_SUBVOL_QGROUP_INHERIT	(1ULL << 2)
-#define BTRFS_DEVICE_BY_ID		(1ULL << 3)
-#define BTRFS_VOL_ARG_V2_FLAGS				\
+#define BTRFS_DEVICE_SPEC_BY_ID		(1ULL << 3)
+
+#define BTRFS_VOL_ARG_V2_FLAGS_SUPPORTED		\
 			(BTRFS_SUBVOL_CREATE_ASYNC |	\
 			BTRFS_SUBVOL_RDONLY |		\
 			BTRFS_SUBVOL_QGROUP_INHERIT |	\
-			BTRFS_DEVICE_BY_ID)
+			BTRFS_DEVICE_SPEC_BY_ID)
 
 #define BTRFS_FSID_SIZE 16
 #define BTRFS_UUID_SIZE 16