[PATCH 3.16.y-ckt 30/94] btrfs: check unsupported filters in balance arguments

[Luis Henriques]

3.16.7-ckt20 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Sterba <dsterba@xxxxxxxx>

commit 8eb934591f8bf584969454a658f629cd06e59f3a upstream.

We don't verify that all the balance filter arguments supplemented by
the flags are actually known to the kernel. Thus we let it silently pass
and do nothing.

At the moment this means only the 'limit' filter, but we're going to add
a few more soon so it's better to have that fixed. Also in older stable
kernels so that it works with newer userspace tools.

Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Chris Mason <clm@xxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
 fs/btrfs/ioctl.c   | 5 +++++
 fs/btrfs/volumes.h | 8 ++++++++
 2 files changed, 13 insertions(+)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index b9d2ce0d4093..8b71c6755e04 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4528,6 +4528,11 @@ locked:
 		bctl->flags |= BTRFS_BALANCE_TYPE_MASK;
 	}
 
+	if (bctl->flags & ~(BTRFS_BALANCE_ARGS_MASK | BTRFS_BALANCE_TYPE_MASK)) {
+		ret = -EINVAL;
+		goto out_bargs;
+	}
+
 do_balance:
 	/*
 	 * Ownership of bctl and mutually_exclusive_operation_running
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 2aaa00c47816..4292c68196ff 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -260,6 +260,14 @@ struct map_lookup {
 #define BTRFS_BALANCE_ARGS_VRANGE	(1ULL << 4)
 #define BTRFS_BALANCE_ARGS_LIMIT	(1ULL << 5)
 
+#define BTRFS_BALANCE_ARGS_MASK			\
+	(BTRFS_BALANCE_ARGS_PROFILES |		\
+	 BTRFS_BALANCE_ARGS_USAGE |		\
+	 BTRFS_BALANCE_ARGS_DEVID | 		\
+	 BTRFS_BALANCE_ARGS_DRANGE |		\
+	 BTRFS_BALANCE_ARGS_VRANGE |		\
+	 BTRFS_BALANCE_ARGS_LIMIT)
+
 /*
  * Profile changing flags.  When SOFT is set we won't relocate chunk if
  * it already has the target profile (even though it may be
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