Hi!

> Thankfully it's handled by the only caller, btree_write_cache_pages(),
> as later write_one_eb() call will trigger submit_one_bio().  So there
> shouldn't be any problem.

This explains there should not be any problem in _the
mainline_. AFAICT this talks about this code. Mainline version is:

 prev_eb = eb;
 ret = lock_extent_buffer_for_io(eb, &epd);
 if (!ret) {
 	free_extent_buffer(eb);
 	continue;
 } else if (ret < 0) {
 	done = 1;
 	free_extent_buffer(eb);
 	break;
 }

But 4.19 has:

 ret = lock_extent_buffer_for_io(eb, fs_info, &epd);
 if (!ret) {
  	free_extent_buffer(eb);
 	continue;
 }

IOW missing the code mentioned in the changelog. Is 0607eb1d452d4
prerequisite for this patch?

Best regards,
								Pavel

> +/*
> + * Lock eb pages and flush the bio if we can't the locks
> + *
> + * Return  0 if nothing went wrong
> + * Return >0 is same as 0, except bio is not submitted
> + * Return <0 if something went wrong, no page is locked
> + */

-- 
http://www.livejournal.com/~pavelmachek