diff options
| -rw-r--r-- | fs/btrfs/ioctl.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 18e328ce4b54..12ae31e1813e 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -4252,7 +4252,19 @@ static long btrfs_ioctl_scrub(struct file *file, void __user *arg) &sa->progress, sa->flags & BTRFS_SCRUB_READONLY, 0); - if (ret == 0 && copy_to_user(arg, sa, sizeof(*sa))) + /* + * Copy scrub args to user space even if btrfs_scrub_dev() returned an + * error. This is important as it allows user space to know how much + * progress scrub has done. For example, if scrub is canceled we get + * -ECANCELED from btrfs_scrub_dev() and return that error back to user + * space. Later user space can inspect the progress from the structure + * btrfs_ioctl_scrub_args and resume scrub from where it left off + * previously (btrfs-progs does this). + * If we fail to copy the btrfs_ioctl_scrub_args structure to user space + * then return -EFAULT to signal the structure was not copied or it may + * be corrupt and unreliable due to a partial copy. + */ + if (copy_to_user(arg, sa, sizeof(*sa))) ret = -EFAULT; if (!(sa->flags & BTRFS_SCRUB_READONLY)) |