Patch "btrfs: prevent to set invalid default subvolid" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    btrfs: prevent to set invalid default subvolid

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     btrfs-prevent-to-set-invalid-default-subvolid.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 6d6d282932d1a609e60dc4467677e0e863682f57 Mon Sep 17 00:00:00 2001
From: satoru takeuchi <satoru.takeuchi@gmail.com>
Date: Tue, 12 Sep 2017 22:42:52 +0900
Subject: btrfs: prevent to set invalid default subvolid

From: satoru takeuchi <satoru.takeuchi@gmail.com>

commit 6d6d282932d1a609e60dc4467677e0e863682f57 upstream.

`btrfs sub set-default` succeeds to set an ID which isn't corresponding to any
fs/file tree. If such the bad ID is set to a filesystem, we can't mount this
filesystem without specifying `subvol` or `subvolid` mount options.

Fixes: 6ef5ed0d386b ("Btrfs: add ioctl and incompat flag to set the default mount subvol")
Signed-off-by: Satoru Takeuchi <satoru.takeuchi@gmail.com>
Reviewed-by: Qu Wenruo <quwenruo.btrfs@gmx.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/btrfs/ioctl.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4082,6 +4082,10 @@ static long btrfs_ioctl_default_subvol(s
 		ret = PTR_ERR(new_root);
 		goto out;
 	}
+	if (!is_fstree(new_root->objectid)) {
+		ret = -ENOENT;
+		goto out;
+	}
 
 	path = btrfs_alloc_path();
 	if (!path) {


Patches currently in stable-queue which might be from satoru.takeuchi@gmail.com are

queue-4.9/btrfs-prevent-to-set-invalid-default-subvolid.patch