As discussed here [1], there are a few places in ext4 and jbd2 code where it
is assumed that a tid of '0' is not valid.  Which isn't true.

This small patchset tries to fix (hopefully!) all these places.  Jan Kara
had already identified the functions that needed to be fixed.  I believe
that the only other issue is the handling of sbi->s_fc_ineligible_tid.

Each patch in this series fixes a single function; the last one also fixes
the sbi->s_fc_ineligible_tid handling.

[1] https://lore.kernel.org/all/20240716095201.o7kkrhfdy2bps3rw@quack3/

Luis Henriques (SUSE) (4):
  ext4: fix incorrect tid assumption in ext4_wait_for_tail_page_commit()
  ext4: fix incorrect tid assumption in __jbd2_log_wait_for_space()
  ext4: fix incorrect tid assumption in
    jbd2_journal_shrink_checkpoint_list()
  ext4: fix incorrect tid assumption in ext4_fc_mark_ineligible()

 fs/ext4/fast_commit.c | 15 +++++++++++----
 fs/ext4/inode.c       | 10 ++++++----
 fs/jbd2/checkpoint.c  | 15 +++++++++++----
 3 files changed, 28 insertions(+), 12 deletions(-)