From f8c6759f29db7b78ed3bc042ced53aa6bcdcb4aa Mon Sep 17 00:00:00 2001
From: David Sterba <dsterba@suse.com>
Date: Mon, 18 Jun 2018 17:56:22 +0200
Subject: [PATCH] btrfs-progs: btrfstune: prepare for enhanced mount check

We'll want to pass non-default superblock flags so let's use the other
helper that allows that. We can reuse the filesystem handle so it needs
to open it read-write, unlike what the plain check_mounted does.

Signed-off-by: David Sterba <dsterba@suse.com>
---
 btrfstune.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/btrfstune.c b/btrfstune.c
index eccedf79..889b931c 100644
--- a/btrfstune.c
+++ b/btrfstune.c
@@ -394,6 +394,7 @@ int main(int argc, char *argv[])
 	char *new_fsid_str = NULL;
 	int ret;
 	u64 super_flags = 0;
+	int fd = -1;
 
 	while(1) {
 		static const struct option long_options[] = {
@@ -467,17 +468,25 @@ int main(int argc, char *argv[])
 		}
 	}
 
-	ret = check_mounted(device);
-	if (ret < 0) {
-		error("could not check mount status of %s: %s", device,
-			strerror(-ret));
-		return 1;
-	} else if (ret) {
-		error("%s is mounted", device);
+	fd = open(device, O_RDWR);
+	if (fd < 0) {
+		error("mount check: cannot open %s: %m", device);
 		return 1;
 	}
 
-	root = open_ctree(device, 0, ctree_flags);
+	ret = check_mounted_where(fd, device, NULL, 0, NULL, SBREAD_DEFAULT);
+	if (ret < 0) {
+		error("could not check mount status of %s: %s", device,
+			strerror(-ret));
+		close(fd);
+		return 1;
+	} else if (ret) {
+		error("%s is mounted", device);
+		close(fd);
+		return 1;
+	}
+
+	root = open_ctree_fd(fd, device, 0, ctree_flags);
 
 	if (!root) {
 		error("open ctree failed");