On Tue, 2017-06-06 at 17:19 +0800, Eryu Guan wrote: > On Wed, May 31, 2017 at 09:08:20AM -0400, Jeff Layton wrote: > > With btrfs, we can't really put the log on a separate device. What we > > can do however is mirror the metadata across two devices and make the > > data striped across all devices. When we turn on dmerror then the > > metadata can fall back to using the other mirror while the data errors > > out. > > > > Note that the current incarnation of btrfs has a fixed 64k stripe > > width. If that ever changes or becomes settable, we may need to adjust > > the amount of data that the test program writes. > > > > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> > > --- > > common/rc | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/common/rc b/common/rc > > index 83765aacfb06..078270451b53 100644 > > --- a/common/rc > > +++ b/common/rc > > @@ -830,6 +830,8 @@ _scratch_mkfs() > > ;; > > btrfs) > > mkfs_cmd="$MKFS_BTRFS_PROG" > > + [ "$USE_EXTERNAL" = yes -a ! -z "$SCRATCH_LOGDEV" ] && \ > > + mkfs_cmd="$mkfs_cmd -d raid0 -m raid1 $SCRATCH_LOGDEV" > > I don't think this is the correct way to do it. If btrfs doesn't support > external log device, then this test doesn't fit btrfs, or we need other > ways to test btrfs. > > One of the problems of this hack is that raid1 requires all devices are > in the same size, we have a _require_scratch_dev_pool_equal_size() rule > to check on it, but this hack doesn't do the proper check and test fails > if SCRATCH_LOGDEV is smaller or bigger in size. > > If btrfs "-d raid0 -m raid1" is capable to do this writeback error test, > perhaps you can write a new btrfs test and mkfs with "-d raid0 -m raid1" > explicitly. e.g. > > ... > _require_scratch_dev_pool 2 > _require_scratch_dev_pool_equal_size > ... > _scratch_mkfs "-d raid0 -m raid1" > ... > > Thanks, > Eryu Yeah, that's probably the right way to do this. It looks like btrfs also has $SCRATCH_DEV_POOL, and we can probably base it on that. I'll look at reworking it. -- Jeff Layton <jlayton@xxxxxxxxxx>
