btrfs: implement decoding of BTRFS_IOC_FORGET_DEV argument

... introduced by Linux kernel commit v5.1-rc1~47^2~47.

* btrfs.c (btrfs_ioctl) [BTRFS_IOC_FORGET_DEV]: Handle
BTRFS_IOC_FORGET_DEV.
* tests/btrfs.c (btrfs_test_device_ioctls) [BTRFS_IOC_FORGET_DEV]:
Check it.

2 files changed, 14 insertions, 0 deletions

diff --git a/btrfs.c b/btrfs.c
index b8fa1091f..dc5eff1a2 100644
--- a/btrfs.c
+++ b/btrfs.c
@@ -1161,6 +1161,9 @@ MPERS_PRINTER_DECL(int, btrfs_ioctl,
 	case BTRFS_IOC_SNAP_CREATE:
 	case BTRFS_IOC_RESIZE:
 	case BTRFS_IOC_SCAN_DEV:
+# ifdef BTRFS_IOC_FORGET_DEV
+	case BTRFS_IOC_FORGET_DEV:
+# endif
 	case BTRFS_IOC_ADD_DEV:
 	case BTRFS_IOC_RM_DEV:
 	case BTRFS_IOC_SUBVOL_CREATE:
diff --git a/tests/btrfs.c b/tests/btrfs.c
index 27ace56fa..1fd5d55a5 100644
--- a/tests/btrfs.c
+++ b/tests/btrfs.c
@@ -752,6 +752,17 @@ btrfs_test_device_ioctls(void)
 	printf("ioctl(-1, %s, {fd=%d, name=\"%s\"}) = -1 EBADF (%m)\n",
 	       ioc(BTRFS_IOC_SCAN_DEV), (int) args.fd, args.name);
 
+# ifdef BTRFS_IOC_FORGET_DEV
+	ioctl(-1, BTRFS_IOC_FORGET_DEV, NULL);
+	printf("ioctl(-1, %s, NULL) = -1 EBADF (%m)\n",
+	       ioc(BTRFS_IOC_FORGET_DEV));
+
+	strcpy(args.name, devname);
+	ioctl(-1, BTRFS_IOC_FORGET_DEV, &args);
+	printf("ioctl(-1, %s, {fd=%d, name=\"%s\"}) = -1 EBADF (%m)\n",
+	       ioc(BTRFS_IOC_FORGET_DEV), (int) args.fd, args.name);
+# endif
+
 	ioctl(-1, BTRFS_IOC_ADD_DEV, NULL);
 	printf("ioctl(-1, %s, NULL) = -1 EBADF (%m)\n", ioc(BTRFS_IOC_ADD_DEV));