Hi, I was wondering how (excluding possible crashes) dm-integrity guarantees that the hashes that it stores for each sector is consistent with the data for each sector. I've been told that outside of FUAs or flushes, block IOs can be arbitrarily reordered (see this article https://lwn.net/Articles/400541/). So, let's say there are 2 write operations, A and B, writing to the same sector, not separated by any FUA or flushes. We know that even if they are concurrent, dm-integrity will ensure that they are not submitted concurrently: write A must complete first (its end_io is called) before write B is submitted. This is the add_new_range() logic, if I am interpreting it correctly. In this case, the hash of write B is written to disk. Can the disk order write B before write A, thereby making the hash check fail? Or is there an ordering guarantee, that if write B is submitted after write A's end_io, it must be ordered after? The add_new_range() logic seems to suggest that that is the case. Are there any special flags that dm-integrity appends in order to get this ordering guarantee? Thanks, David
