On Fri, Nov 16, 2018 at 08:06:36PM +0800, Anand Jain wrote:
>
>
> On 11/15/2018 11:35 PM, David Sterba wrote:
> > On Sun, Nov 11, 2018 at 10:22:22PM +0800, Anand Jain wrote:
> >> When we successfully cancel the replace its scrub returns -ECANCELED,
> >> which then passed to btrfs_dev_replace_finishing(), it cleans up based
> >> on the scrub returned status and propagates the same -ECANCELED back
> >> the parent function. As of now only user can cancel the replace-scrub,
> >> so its ok to quieten the warn here.
> >>
> >> Signed-off-by: Anand Jain <anand.j...@oracle.com>
> >> ---
> >> fs/btrfs/dev-replace.c | 4 ++--
> >> 1 file changed, 2 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
> >> index 1dc8e86546db..9031a362921a 100644
> >> --- a/fs/btrfs/dev-replace.c
> >> +++ b/fs/btrfs/dev-replace.c
> >> @@ -497,7 +497,7 @@ static int btrfs_dev_replace_start(struct
> >> btrfs_fs_info *fs_info,
> >> ret = btrfs_dev_replace_finishing(fs_info, ret);
> >> if (ret == -EINPROGRESS) {
> >> ret = BTRFS_IOCTL_DEV_REPLACE_RESULT_SCRUB_INPROGRESS;
> >> - } else {
> >> + } else if (ret != -ECANCELED) {
> >> WARN_ON(ret);
> >
> > While this looks ok, can you please rework it so there are no WARN_ON at
> > random places in device-replace, poorly substituting error handling?
> >
> > The code flow in this case could be changed to make explicit checks for
> > the know codes and then a catch-all branch like:
> >
> > if (ret == -EINPROGRESS) {
> > ...
> > } else (if == -ESOMETHINGELSE) {
> > ...
> > } else {
> > unknown error, print error and do a proper cleanup
> > }
> >
>
> As below..
>
> >> }
> >>
> >> @@ -954,7 +954,7 @@ static int btrfs_dev_replace_kthread(void *data)
> >> btrfs_device_get_total_bytes(dev_replace->srcdev),
> >> &dev_replace->scrub_progress, 0, 1);
> >> ret = btrfs_dev_replace_finishing(fs_info, ret);
> >> - WARN_ON(ret);
> >> + WARN_ON(ret && ret != -ECANCELED);
> >
> > This one too, thanks.
>
>
> btrfs_dev_scrub() can return quite a lot of errno, which is passed
> here through the btrfs_dev_replace_finishing(), so it won't be
> possible to code them all.
>
> (we use -ECANCELED only in replace and balance).
I see, filtering out only the replace error codes makes more sense.
