Re: kern/59563: Use of FS_UFS2_MAGIC is problematic

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

The following reply was made to PR kern/59563; it has been noted by GNATS.

From: Christos Zoulas <christos%zoulas.com@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: kern-bug-people%netbsd.org@localhost,
 gnats-admin%netbsd.org@localhost,
 netbsd-bugs%netbsd.org@localhost
Subject: Re: kern/59563: Use of FS_UFS2_MAGIC is problematic
Date: Tue, 29 Jul 2025 15:09:41 -0400

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 Does not matter, because:
 
         /* Allow converting from UFS2 to UFS2EA but not vice versa. */
         if (newfs->fs_magic =3D=3D FS_UFS2EA_MAGIC) {
                 ump->um_flags |=3D UFS_EA;
                 newfs->fs_magic =3D FS_UFS2_MAGIC;
         } else {
                 if ((ump->um_flags & UFS_EA) !=3D 0)
                         return EINVAL;
         }
 
 If that was not the case we would get corruption and crashes. But I =
 agree with you, it is better to do the test one way and perhaps put it =
 in a macro.
 
 christos=
 
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