Patch "btrfs: fix btrfs_compat_ioctl failures on non-compat ioctls" has been added to the 4.9-stable tree

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

btrfs: fix btrfs_compat_ioctl failures on non-compat ioctls

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-fix-btrfs_compat_ioctl-failures-on-non-compat-ioctls.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 <[email protected]> know about it.

From: Jeff Mahoney <[email protected]>
Date: Mon, 6 Feb 2017 19:39:09 -0500
Subject: btrfs: fix btrfs_compat_ioctl failures on non-compat ioctls

From: Jeff Mahoney <[email protected]>

commit 2a362249187a8d0f6d942d6e1d763d150a296f47 upstream.

Commit 4c63c2454ef incorrectly assumed that returning -ENOIOCTLCMD would cause the native ioctl to be called. The ->compat_ioctl callback is expected to handle all ioctls, not just compat variants. As a result, when using 32-bit userspace on 64-bit kernels, everything except those three ioctls would return -ENOTTY.

---
 fs/btrfs/ioctl.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

@@ -5648,6 +5648,10 @@ long btrfs_ioctl(struct file *file, unsi
 #ifdef CONFIG_COMPAT
 long btrfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
+	/*
+	 * These all access 32-bit values anyway so no further
+	 * handling is necessary.
+	 */
 	switch (cmd) {
 	case FS_IOC32_GETFLAGS:
 		cmd = FS_IOC_GETFLAGS;

@@ -5658,8 +5662,6 @@ long btrfs_compat_ioctl(struct file *fil
 	case FS_IOC32_GETVERSION:
 		cmd = FS_IOC_GETVERSION;
 		break;
-	default:
-		return -ENOIOCTLCMD;
 	}
 
 	return btrfs_ioctl(file, cmd, (unsigned long) compat_ptr(arg));

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/btrfs-fix-btrfs_compat_ioctl-failures-on-non-compat-ioctls.patch