BTRFS_IOC_TRANS_START should be privilegued

As mentioned in the comment next to it btrfs_ioctl_trans_start can
do bad damage to filesystems and thus should be limited to privilegued
users.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index da8de6cfdb5a3eb9ae7451f221e3f134e18a878e..6fb455802759ea268b2e2c0e9ce46e24a595e7cc 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -706,6 +706,9 @@ long btrfs_ioctl_trans_start(struct file *file)
        struct btrfs_trans_handle *trans;
        int ret = 0;
 
+       if (!capable(CAP_SYS_ADMIN))
+               return -EPERM;
+
        mutex_lock(&root->fs_info->fs_mutex);
        if (file->private_data) {
                ret = -EINPROGRESS;