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