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

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

[gregkh]

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 <stable@vger.kernel.org> know about it.


>From 2a362249187a8d0f6d942d6e1d763d150a296f47 Mon Sep 17 00:00:00 2001
From: Jeff Mahoney <jeffm@suse.com>
Date: Mon, 6 Feb 2017 19:39:09 -0500
Subject: btrfs: fix btrfs_compat_ioctl failures on non-compat ioctls

From: Jeff Mahoney <jeffm@suse.com>

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.

Fixes: 4c63c2454ef ("btrfs: bugfix: handle FS_IOC32_{GETFLAGS,SETFLAGS,GETVERSION} in btrfs_ioctl")
Signed-off-by: Jeff Mahoney <jeffm@suse.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 |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -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 jeffm@suse.com are

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