https://bugzilla.kernel.org/show_bug.cgi?id=200015 Theodore Tso (tytso@xxxxxxx) changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |tytso@xxxxxxx --- Comment #2 from Theodore Tso (tytso@xxxxxxx) --- Thanks for the simplified POC. But unfortunately that doesn't really tell me anything new. What I need is a simplified POC *image*. I can add a simplistic check to see if we get a negative group number in ext4_discard_preallocations(), but that's not the real root cause. And it wouldn't be a complete solution, since we would have add gazillions of checks anywhere we use s_first_data_block. It's much better if we can check s_first_data_block at mount time (which we do), and then make sure that it can't get corrupted afterwards. So the real root cause is somehow, the superblock buffer has gotten corrupted. We have a lot of checks to prevent this from happening --- that's what the ext4_data_block_valid() function in fs/ext4/block_validity.c is all about --- but obviously, we're missing a check somewhere. The question is where. If we had a simplified POC image, I could look to find the file system corruption that was causing the superblock to get trashed. The problem is that there are so many random corruptions, many of them completely irrelevant to the bug at hand, that this is extremely difficult. -- You are receiving this mail because: You are watching the assignee of the bug.
