When adding the comments for subpage metadata code, I inserted the comment patch into the wrong position, and then use that patch as a separator between data and metadata write path.
Thus the submitted metadata write path patchset lacks the real functions to submit subpage metadata write bio. Qu Wenruo (4): btrfs: introduce end_bio_subpage_eb_writepage() function btrfs: introduce write_one_subpage_eb() function btrfs: make lock_extent_buffer_for_io() to be subpage compatible btrfs: introduce submit_eb_subpage() to submit a subpage metadata page fs/btrfs/extent_io.c | 293 ++++++++++++++++++++++++++++++++++++++----- 1 file changed, 263 insertions(+), 30 deletions(-) -- 2.31.1