Bugs in fsck(8) and fsck_ufs(8)

[Polytropon]

On Sun, 12 Feb 2017 19:09:59 -0800, Perry Hutchison wrote:
> I have a UFS filesystem that will not mount, and it confuses fsck(8):
> 
> # mount /dev/da2p2 /mnt
> mount: /dev/da2p2 : Operation not permitted
> 
> # fsck /dev/da2p2
> fsck: Could not determine filesystem type
> 
> Why can't fsck(8) recognize the filesystem type?

If I remember correctly, the information for the -t option is
taken from /etc/fstab, so when /dev/da2p2 doesn't have an entry
in that file, fsck will not automatically select the right type.



> To be outdone by file(1) in filesystem type recognition is pretty
> clearly a bug in fsck(8), but not a terribly serious one since it
> can be gotten around easy enough by running fsck_ufs(8) directly.

Or use "fsck -t ufs" plus additional options you might need.



> However, fsck_ufs(8) also has trouble with this filesystem:  it
> claims something is wrong, but it doesn't even identify any specific
> problems much less fix them:
> 
> # fsck_ufs /dev/da2p2
> ** /dev/da2p2
> ** Last Mounted on /mnt
> ** Phase 1 - Check Blocks and Sizes
> ** Phase 2 - Check Pathnames
> ** Phase 3 - Check Connectivity
> ** Phase 4 - Check Reference Counts
> ** Phase 5 - Check Cyl groups
> 13527 files, 628739 used, 43580 free (236 frags, 5418 blocks,
> 0.0% fragmentation)
> 
> ***** FILE SYSTEM STILL DIRTY *****
> 
> ***** PLEASE RERUN FSCK *****

Do you have journaling enabled with UFS for that file system?
Any other "non-standard" options which might be interfering?



> So it seems this filesystem also provokes a bug in fsck_ufs(8):
> any problem serious enough to not mark the filesystem as clean
> is serious enough to at least report, if not fix.  (I've rerun
> it several times, always getting the same result.)

That indicates a severe problem with the file system.



> I'd try falling back to lower-level tools, but it seems they no
> longer exist:
> 
> # which icheck
> icheck: Command not found.
> 
> # which dcheck
> dcheck: Command not found.
> 
> # which ncheck
> ncheck: Command not found.
> 
> Now what?

A lower-level tool included with the OS is "fsdb".



-- 
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...