Re: [BUG] two raid consistency bugs

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

在 2026/7/15 01:40, Zhang Boyang 写道:
> Hello btrfs devs,
> 
> I found two raid-related bugs in btrfs. Two test cases are provided.
> 
> 
> BUG 1. fstests: btrfs/348: test ambiguous generation handling on raid1 profile
> 
> This test simulates a ambiguous generation which can be caused by, for
> example, two successive power failures. Please note this is not related
> to degraded mounts or nodatacow.
> 
> This bug may affect several raid levels, take raid1 (say disk A and B)
> as an example:
> 
> At first power failure during transaction N, metadata trees of
> generation N are written to disk A, but super is not committed. Nothing
> is written to disk B.
> 
> At second power failure during a different transaction N,

If it's a different transaction, why it will still have the same transid N?

> nothing is
> written to disk A, but metadata trees and super is committed to disk B.
> 
> This creates a ambiguous generation N in two disks. Currently btrfs
> can't detect this, and can lead to severe damages.