[PATCH 0/2] btrfs: fixes for subpage which also affect read-only mount

[Qu Wenruo <wqu@suse.com>]

During the fstests run for btrfs subpage read-write support, generic/475
crashes the system with a very high chance.

It turns out the cause is also affecting btrfs subpage read-only mount
so it's worthy a quick fix.

Also the crash call site shows a new rabbit hole of hard coded
PAGE_SHIFT in readahead.
This reada problem does not only greatly slow down my test on my ARM
board, but also affects read-only mount.

So this patchset is here to address the problems, and hope these fixes
can fit into current merge window.

Qu Wenruo (2):
  btrfs: fix wild pointer access during metadata read failure for
    subpage
  btrfs: make reada to be subpage compatible

 fs/btrfs/extent_io.c | 31 ++++++++++++++++++++++++++++++-
 fs/btrfs/reada.c     | 35 ++++++++++++++++++-----------------
 2 files changed, 48 insertions(+), 18 deletions(-)

-- 
2.30.1