Re: kern/60855: FFSv2ea superblok mismatch

["Phako via gnats" <gnats-admin%NetBSD.org@localhost>]

The following reply was made to PR kern/60855; it has been noted by GNATS.

From: Phako <phako%free.fr@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: kern/60855: FFSv2ea superblok mismatch
Date: Sat, 31 Oct 2026 16:29:50 +0100

 Le 29/10/2026 à 01:05, Showta Ishizaki via gnats a écrit :
 > The following reply was made to PR kern/60855; it has been noted by GNATS.
 > 
 > From: Showta Ishizaki <zakinko%snowrabbit.org@localhost>
 >   I ran into the same thing while testing UFS2ea images in CI: a file
 >   system made with newfs -O 2ea fails fsck_ffs -n -f with "ALTERNATE
 >   SUPERBLK(S) ARE INCORRECT" straight after newfs.  As far as I can tell
 >   there are two causes, one in newfs and one in fsck_ffs.
 >   
 
 [...]>   File systems that already have the wrong alternates can be repaired
 >   with fsck_ffs -y -f, even without the patch, since pass5 rewrites the
 >   alternates from the superblock.
 >   
 
 I don't understand all the implications of this response (eg: does it 
 correct also the following problem or not) but I have found a new 
 unexpected behavior:
 With a newly created FFSv2ea filesystem and non repaired by fsck_ffs, 
 checking it with the -n -X options (Use internal snapshot to check a 
 mounted FS) on it once mounted, no error are reported.  And inversely 
 when a mounted but now repaired filesystem, running fsck_ffs -n -X, get 
 you back the error "ALTERNATE SUPERBLK(S) ARE INCORRECT".
 
 Regards