CVS commit: src/sys/kern

["YAMAMOTO Takashi" <yamt%netbsd.org@localhost>]

Module Name:    src
Committed By:   yamt
Date:           Fri Mar 27 23:43:13 UTC 2026

Modified Files:
        src/sys/kern: vfs_init.c

Log Message:
vfs_attach: reject file system with non-unique fstype

while currently our fstype values are still unique, given the poor
hash function used by makefstype [1], it isn't too unlikely for a future
or out-of-tree file system to have a conflicting value. it's safer
to reject it explicitly. note that, we can't lightly change the hash
function because it's exposed as a part of nfs file handles.

[1] for example, makefstype("qa") == makefstype("uq") == 0x1a5.

the current list of fstype values used by the in-tree file systems:

    0000064b zfs
    000006a6 udf
    0000070b nfs
    0000072b lfs
    0000073b mfs
    0000076b hfs
    0000078b ffs
    000007bb efs
    000007fb afs
    00001a64 umap
    00001d0c null
    00001d2b ntfs
    00001f1b v7fs
    00001fc1 coda
    000069ab tmpfs
    000069c2 union
    00006acb puffs
    00006b7b ptyfs
    00006f8b smbfs
    0000736b nilfs
    0000764f msdos
    000078ff fdesc
    0001a0ab rumpfs
    0001ae1b procfs
    0001d28b kernfs
    0001e5c8 cd9660
    0001eb1b autofs
    0001f3cb ext2fs
    0001fd1b adosfs
    0006bd4b sysvbfs
    000756bd overlay
    001eda9d filecore

related to PR/60135
https://gnats.netbsd.org/60135


To generate a diff of this commit:
cvs rdiff -u -r1.67 -r1.68 src/sys/kern/vfs_init.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.