On Thu, Aug 29, 2019 at 09:22:36PM -0400, Theodore Y. Ts'o wrote: > (Changing the cc from linux-fsdevel to linux-ext4.) > > On Thu, Aug 29, 2019 at 04:53:48PM -0600, dann frazier wrote: > > JBD2: Invalid checksum recovering data block 517634 in log > > > > So is it correct to say that the checksum errors were identifying > > filesystem correctness issues, and therefore e2fsck was needed to > > correct them? > > That's correct. More precisely, checksum errors for journal blocks > are presumed to mean that file system might be corrupt, so a full > e2fsck check was needed to make sure the file system was consistent. > > > You're probably right - this issue is very easy to reproduce w/ > > data=journal,journal_checksum. I was never able to reproduce it > > otherwise. > > I've looked at the data block numbers that you've reported, and they > come from a journald file. The problem is with data=journal + > journal_checksum + mmap. Unfortunately, we don't handle that > combination correctly at the moment. > > The fix is going to have to involve fixing __ext4_journalled_writepage() > to call set_page_writeback() before it unlocks the page, adding a list of > pages under data=journalled writeback which is attached to the > transaction handle, have the jbd2 commit hook call end_page_writeback() > on all of these pages, and then in the places where ext4 calls > wait_for_stable_page() or grab_cache_page_write_begin(), > we need to add: > > if (ext4_should_journal_data(inode)) > wait_on_page_writeback(page); > > It's all relatively straightforward except for the part where we have to > attach a list of pages to the currently running transaction. That > will require adding some plumbing into the jbd2 layer. > > Dann, any interest in trying to code this fix? Thanks Ted. I've the interest, I'll see if I can find the time :) -dann
