From 20916c2846303e900f00e3206df5a011a87c5494 Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Fri, 15 Nov 2013 09:05:43 +0000
Subject: [PATCH] daemon: btrfs: Upstream 'btrfs device add' command now needs
 '--force' option to work.

However earlier versions didn't have the --force option, so we
have to detect it.

(cherry picked from commit 59596810b009744316941da8ef18b7e75b503b9f)
(cherry picked from commit 899d0af8291baa1b714024fcdd684db10f4ae262)
---
 daemon/btrfs.c | 35 +++++++++++++++++++++++++++++++----
 1 file changed, 31 insertions(+), 4 deletions(-)

diff --git a/daemon/btrfs.c b/daemon/btrfs.c
index 765dec6..0b877f8 100644
--- a/daemon/btrfs.c
+++ b/daemon/btrfs.c
@@ -588,14 +588,29 @@ do_btrfs_filesystem_balance (const char *fs)
   return 0;
 }
 
+/* Test if 'btrfs device add' needs the --force option (added
+ * c.2013-09) in order to work.
+ */
+static int
+test_btrfs_device_add_needs_force (void)
+{
+  int r;
+  CLEANUP_FREE char *out = NULL, *err = NULL;
+
+  r = command (&out, &err, "btrfs", "device", "add", "--help", NULL);
+  if (r == -1) {
+    reply_with_error ("%s: %s", "btrfs device add --help", err);
+    return -1;
+  }
+
+  return strstr (out, "--force") != NULL;
+}
+
 int
 do_btrfs_device_add (char *const *devices, const char *fs)
 {
+  static int btrfs_device_add_needs_force = -1;
   size_t nr_devices = count_strings (devices);
-
-  if (nr_devices == 0)
-    return 0;
-
   size_t MAX_ARGS = nr_devices + 8;
   const char *argv[MAX_ARGS];
   size_t i = 0, j;
@@ -603,6 +618,15 @@ do_btrfs_device_add (char *const *devices, const char *fs)
   CLEANUP_FREE char *err = NULL;
   int r;
 
+  if (nr_devices == 0)
+    return 0;
+
+  if (btrfs_device_add_needs_force == -1) {
+    btrfs_device_add_needs_force = test_btrfs_device_add_needs_force ();
+    if (btrfs_device_add_needs_force == -1)
+      return -1;
+  }
+
   fs_buf = sysroot_path (fs);
   if (fs_buf == NULL) {
     reply_with_perror ("malloc");
@@ -613,6 +637,9 @@ do_btrfs_device_add (char *const *devices, const char *fs)
   ADD_ARG (argv, i, "device");
   ADD_ARG (argv, i, "add");
 
+  if (btrfs_device_add_needs_force)
+    ADD_ARG (argv, i, "--force");
+
   for (j = 0; j < nr_devices; ++j)
     ADD_ARG (argv, i, devices[j]);
 
-- 
1.8.3.1