From d3a53286c191c3d598eae09a68bb99a0db4e2466 Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Tue, 8 Jan 2019 11:42:09 +0000 Subject: [PATCH] Btrfs: do not overwrite error return value in the device replace ioctl If the call to btrfs_dev_replace_by_ioctl() failed we would overwrite the error returned to user space with -EFAULT if the call to copy_to_user() failed as well. Fix that by calling copy_to_user() only if no error happened before or a device replace operation was canceled. Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/ioctl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 816fa7dce79f..b07b19acdbb1 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -4475,7 +4475,7 @@ static long btrfs_ioctl_dev_replace(struct btrfs_fs_info *fs_info, break; } - if (copy_to_user(arg, p, sizeof(*p))) + if ((ret == 0 || ret == -ECANCELED) && copy_to_user(arg, p, sizeof(*p))) ret = -EFAULT; out: kfree(p);