btrfs: error handling fixes

[CHANGELOG]
v4:
- Rebased to the latest for-next branch
This involves several minor conflicts due to the recent cleanup.

- Minor comment/commit message update

- Use btrfs_root_id() for error messages

- Fix the double accounting error reintroduced in the last patch Where the run_delalloc_nocow() function has a very weird handling for COW fallback, where @cur_offset can either be @cow_start or @cow_end depending on the fallback_to_cow() entrance.

v3:
- Add a new patch to move the ordered extent cleanup into cow_file_range() and run_delalloc_nocow()

- Update the comment of writepage_dealloc()
To give a more detailed view on what should be done for all the 3 return value patterns

- Rename the variable @last_finished to @last_finished_delalloc_end And enhance the comment of it.

- Add a comment on why we want submit_one_bio() after submit_one_sector() failed

- Add a comment explaining what cleanup_dirty_folios() does

- Update the ASCII graph to use @cur_offset other than @cur_start

v2:
- Fix the btrfs_cleanup_ordered_extents() call inside btrfs_run_delalloc_range()

Since we no longer call btrfs_mark_ordered_io_finished() if btrfs_run_delalloc_range() failed, the existing btrfs_cleanup_ordered_extents() call with @locked_folio will cause the subpage range not to be properly cleaned up.

This can lead to hanging ordered extents for subpage cases.

- Update the commit message of the first patch
With more detailed analyse on how the double accounting happens. It's pretty complex and very lengthy, but is easier to understand (as least I hope so).

The root cause is the btrfs_cleanup_ordered_extents()'s range split behavior, which is not subpage compatible and is cursed in the first place.

So the fix is still the same, by removing the split OE handling completely.

- A new patch to cleanup the @locked_folio parameter of btrfs_cleanup_ordered_extents()

I believe there is a regression in the last 2 or 3 releases where metadata/data space reservation code is no longer working properly, result us to hit -ENOSPC during btrfs_run_delalloc_range().

One of the most common situation to hit such problem is during generic/750, along with other long running generic tests.

Although I should start bisecting the space reservation bug, but I can not help but fixing the exposed bugs first.

This exposed quite some long existing bugs, all in the error handling paths, that can lead to the following crashes

- Double ordered extent accounting
Triggers WARN_ON_OCE() inside can_finish_ordered_extent() then crash.

This bug is fixed by the first 3 patches.
The first patch is the most important one, since it's pretty easy to trigger in the real world, and very long existing.

The second patch is just a precautious fix, not easy to happen in the real world.

The third one is also possible in the real world, but only possible with the recently enabled subpage compression write support.

- Subpage ASSERT() triggered, where subpage folio bitmap differs from folio status
This happens most likey in submit_uncompressed_range(), where it unlock the folio without updating the subpage bitmaps.

This bug is fixed by the 3rd patch.

- WARN_ON() if out-of-tree patch "btrfs: reject out-of-band dirty folios during writeback" applied
This is a more complex case, where error handling leaves some folios dirty, but with EXTENT_DELALLOC flag cleared from extent io tree.

Such dirty folios are still possible to be written back later, but since there is no EXTENT_DELALLOC flag, it will be treat as out-of-band dirty flags and trigger COW fixup.

This bug is fixed by the 4th and 5th patch

With so many existing bugs exposed, there is more than enough motivation to make btrfs_run_delalloc_range() (and its delalloc range functions) output extra error messages so that at least we know something is wrong.

And those error messages have already helped a lot during my development.

Patches 6~8 are here to enhance the error messages.

Patch 9 is to cleanup the unnecessary @locked_folio parameter of btrfs_cleanup_ordered_extents().

The final one is to make ordered extent cleanup to be more sane, following the common reclaim-asap principle, other than delay the cleanup until btrfs_run_delalloc_range().

With all these patches applied, at least fstests can finish reliably, otherwise it frequently crashes in generic tests that I was unable to finish even one full run since the space reservation regression.

Qu Wenruo (10):
btrfs: fix double accounting race when btrfs_run_delalloc_range()
failed
btrfs: fix double accounting race when extent_writepage_io() failed
btrfs: fix the error handling of submit_uncompressed_range()
btrfs: do proper folio cleanup when cow_file_range() failed
btrfs: do proper folio cleanup when run_delalloc_nocow() failed
btrfs: subpage: fix the bitmap dump for the locked flags
btrfs: subpage: dump the involved bitmap when ASSERT() failed
btrfs: add extra error messages for delalloc range related errors
btrfs: remove the unused @locked_folio parameter from
btrfs_cleanup_ordered_extents()
btrfs: move ordered extent cleanup to where they are allocated

 fs/btrfs/extent_io.c | 104 ++++++++++++----
 fs/btrfs/inode.c     | 279 ++++++++++++++++++++++++++-----------------
 fs/btrfs/subpage.c   |  47 ++++++--
 fs/btrfs/subpage.h   |  13 ++
 4 files changed, 300 insertions(+), 143 deletions(-)

2.47.1