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

fdmanana
2018-12-14T19:45:18Z

From: Filipe Manana <fdmanana@suse.com>

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.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
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 01d18e1a393e..76848214a39f 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4331,7 +4331,7 @@ 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);
--
2.11.0