[Tfug] incorrect super block

[christopher floess]

> 'magic numbers' that appear in the superblock (I don't know the magic
> numbers for UFS, google probably does). Find a backup superblock
> (usually at block 160, but fsck will probably look here for you), give
> the block number to fsck with the '-b [blocknum]'

Ok, upon some testing, I discovered that fsck in FBSD, doesn't
support the '-b' option. I guess fsck_ufs can be used in it's place,
which does support the -b option. Using

#newfs -N /dev/ad0s2c

gives

super-block backups (for fsck -b #) at:
 160, 376512, 752864, 1129216, 1505568, 1881920, 2258272, 2634624, 3010976,
 3387328, 3763680, 4140032, 4516384, 4892736, 5269088, 5645440, 6021792,
 6398144, 6774496, 7150848, 7527200, 7903552, 8279904, 8656256, 9032608,
 9408960, 9785312, 10161664, 10538016, 10914368, 11290720, 11667072, 12043424,
 12419776, 12796128, 13172480, 13548832, 13925184, 14301536, 14677888,
 15054240, 15430592, 15806944, 16183296, 16559648, 16936000, 17312352,
 17688704, 18065056, 18441408, 18817760, 19194112, 19570464, 19946816,
 20323168, 20699520, 21075872, 21452224, 21828576, 22204928, 22581280,
 22957632, 23333984, 23710336, 24086688, 24463040, 24839392, 25215744,
 25592096, 25968448, 26344800, 26721152, 27097504, 27473856, 27850208,
 28226560, 28602912, 28979264, 29355616, 29731968, 30108320, 30484672,
 30861024, 31237376, 31613728, 31990080, 32366432, 32742784, 33119136,.........

 333824384, 334200736, 334577088, 334953440, 335329792, 335706144, 336082496,
 336458848, 336835200, 337211552, 337587904, 337964256, 338340608, 338716960,
 339093312, 339469664, 339846016, 340222368, 340598720, 340975072, 341351424,
 341727776, 342104128, 342480480, 342856832, 343233184, 343609536, 343985888,
 344362240, 344738592, 345114944, 345491296, 345867648, 346244000, 346620352,
 346996704, 347373056, 347749408, 348125760, 348502112, 348878464, 349254816,
 349631168, 350007520, 350383872, 350760224, 351136576, 351512928, 351889280,
 352265632, 352641984, 353018336, 353394688, 353771040, 354147392, 354523744,
 354900096, 355276448, 355652800, 356029152, 356405504, 356781856, 357158208,
 357534560, 357910912, 358287264, 358663616, 359039968, 359416320, 359792672,
 360169024, 360545376, 360921728, 361298080, 361674432, 362050784, 362427136

and then using a random assortment of these of these numbers in

#fsck_ufs -b 350760224 /dev/ad0s2c

gives

'350760224 is not a file system superblock'

not 160, or any of the other values I tried seemed to work. Like I
said, there is no data to be lost there, so I can go pretty extreme
as long as I don't loose all of my other partitions.

It seems to me that running disklabel then newfs is the way to go
here, but I don't feel confident in my HD knowlege to go forward
without someone reassuring me.

Thanks ~ Chris


-- 
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