[PATCH v2] Btrfs: do not overwrite scrub error with fault error in scrub ioctl

[fdmanana@kernel.org]

From: Filipe Manana <fdmanana@suse.com>

If scrub returned an error and then the copy_to_user() call did not
succeed, we would overwrite the error returned by scrub with -EFAULT.
Fix that by removing the call to copy_to_user() as there is no need
to do it at all.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
---

V2: Leave to copy_to_user() call since progress needs to be reported back
    to user space.

 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 3a27efa2b955..4c05d9c4fe3d 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4301,7 +4301,7 @@ static long btrfs_ioctl_scrub(struct file *file, void __user *arg)
 			      &sa->progress, sa->flags & BTRFS_SCRUB_READONLY,
 			      0);
 
-	if (copy_to_user(arg, sa, sizeof(*sa)))
+	if (ret == 0 && copy_to_user(arg, sa, sizeof(*sa)))
 		ret = -EFAULT;
 
 	if (!(sa->flags & BTRFS_SCRUB_READONLY))
-- 
2.11.0