btrfs: clear block dirty if submit_one_sector() failed

btrfs: clear block dirty if submit_one_sector() failed

[BUG]
If submit_one_sector() failed, the block will be kept dirty, but with
their corresponding range finished in the ordered extent.

This means if a writeback happens later again, we can hit the following
problems:

- ASSERT(block_start != EXTENT_MAP_HOLE) in submit_one_sector()
  If the original extent map is a hole, then we can hit this case, as
  the new ordered extent failed, we will drop the new extent map and
  re-read one from the disk.

- DEBUG_WARN() in btrfs_writepage_cow_fixup()
  This is because we no longer have an ordered extent for those dirty
  blocks. The original for them is already finished with error.

[CAUSE]
The function submit_one_sector() is not following the regular error
handling of writeback.  The common practice is to clear the folio dirty,
start and finish the writeback for the block.

This is normally done by extent_clear_unlock_delalloc() with
PAGE_START_WRITEBACK | PAGE_END_WRITEBACK flags during
run_delalloc_range().

So if we keep those failed blocks dirty, they will stay in the page
cache and wait for the next writeback.

And since the original ordered extent is already finished and removed,
depending on the original extent map, we either hit the ASSERT() inside
submit_one_sector(), or hit the DEBUG_WARN() in
btrfs_writepage_cow_fixup().

[FIX]
Follow the regular error handling to clear the dirty flag for the block,
start and finish writeback for that block instead.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>