From: Filipe Manana <fdmanana@suse.com>
Date: Fri, 14 Dec 2018 19:45:13 +0000 (+0000)
Subject: Btrfs: do not overwrite error return value in scrub progress ioctl
X-Git-Tag: v5.1-rc1~138^2~88
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=4fa99b008fb53ade9bacea51d29b24efee8914a8;p=thirdparty%2Fkernel%2Flinux.git

Btrfs: do not overwrite error return value in scrub progress ioctl

If the call to btrfs_scrub_progress() 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 btrfs_scrub_progress()
returned success.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index d34e54d80149d..02ea03d220e86 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4414,7 +4414,7 @@ static long btrfs_ioctl_scrub_progress(struct btrfs_fs_info *fs_info,
 
 	ret = btrfs_scrub_progress(fs_info, sa->devid, &sa->progress);
 
-	if (copy_to_user(arg, sa, sizeof(*sa)))
+	if (ret == 0 && copy_to_user(arg, sa, sizeof(*sa)))
 		ret = -EFAULT;
 
 	kfree(sa);