[gentoo-user] Re: repair FAT-fs

[Kai Krakow]

Am Fri, 02 Mar 2018 22:17:02 -0700 schrieb thelma:

>>> I 've "dosfstools" installed but I can not run: dosfsck - it doesn't exist.
>>
>>
>> Try 'fsck.vfat' instead. There is also 'fsck.fat' or 'fsck.exfat', at least on my installation.
>
> I've tried:
> fsck.vfat -v -a -w /dev/sdb1
> fsck.fat 4.0 (2016-05-06)
> open: No such file or directory
>
> This doesn't work either:
> fdisk /dev/sdb
>
> Welcome to fdisk (util-linux 2.28.2).
> Changes will remain in memory only, until you decide to write them.
> Be careful before using the write command.
>
> fdisk: cannot open /dev/sdb: No such file or directory
>
>
> Here is a dmesg:
>
> [10930879.950647] usb-storage 8-1:1.0: USB Mass Storage device detected
> [10930879.950742] scsi host8: usb-storage 8-1:1.0
> [10930881.068652] scsi 8:0:0:0: Direct-Access     Kingston DataTraveler G3  PMAP PQ: 0 ANSI: 4
> [10930881.068839] sd 8:0:0:0: Attached scsi generic sg2 type 0
> [10930882.544966] sd 8:0:0:0: [sdb] 30489408 512-byte logical blocks: (15.6 GB/14.5 GiB)
> [10930882.545153] sd 8:0:0:0: [sdb] Write Protect is off
> [10930882.545155] sd 8:0:0:0: [sdb] Mode Sense: 23 00 00 00
> [10930882.545283] sd 8:0:0:0: [sdb] No Caching mode page found
> [10930882.545284] sd 8:0:0:0: [sdb] Assuming drive cache: write through
> [10930882.567263]  sdb: sdb1
> [10930882.568351] sd 8:0:0:0: [sdb] Attached SCSI removable disk
> [10930887.640395] FAT-fs (sdb1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.

This message is probably an artifact of what follows.

> [10930894.488038] sd 8:0:0:0: [sdb] tag#0 FAILED Result: hostbyte=DID_ERROR driverbyte=DRIVER_SENSE
> [10930894.488041] sd 8:0:0:0: [sdb] tag#0 Sense Key : Hardware Error [current]
> [10930894.488043] sd 8:0:0:0: [sdb] tag#0 Add. Sense: No additional sense information
> [10930894.488045] sd 8:0:0:0: [sdb] tag#0 CDB: Synchronize Cache(10) 35 00 00 00 00 00 00 00 00 00

This USB thumb drive is quite obviously broken, or incompatible with your
USB controller. Try a different port or different system. Otherwise,
throw it away and learn not to store important stuff on thumb drives.

Most USB thumb drive use terrifying cheap and weak storage chips, sometimes
supporting only hundreds of write cycles. It's going to break more soon
than later, especially if you write a lot or leave it in the drawer without
connection to a power source for weeks or months.

Some sticks are even crafted in a way to support heavy write-cycles only
where the FAT table is going to be. Reformatting or putting something other
on it than FAT can have catastrophic consequences after a short time.

I was able to completely destroy some cheap USB sticks within a few weeks
by putting f2fs on them.


> [10930894.497472] usb 8-1: USB disconnect, device number 106
> [10932073.936844] usb 3-1: USB disconnect, device number 19

This message means: disconnect, the device node is gone.

> [10932092.353300] usb 3-1: new high-speed USB device number 20 using ehci-pci
> [10932092.473483] usb 3-1: New USB device found, idVendor=1043, idProduct=8012
> [10932092.473486] usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
> [10932092.473487] usb 3-1: Product: Flash Disk
> [10932092.473488] usb 3-1: Manufacturer: Generic


In the future, please ensure to post complete logs right from the
beginning without hiding the important stuff. ;-)


BTW: dosfsck is afair part of the mtools package. On a modern system,
use the fsck.{vfat,fat} equivalents. The message you got tells you
that the device was not found, not that the tool was not found:

> I've tried:
> fsck.vfat -v -a -w /dev/sdb1
> fsck.fat 4.0 (2016-05-06)
  ^^^^^^^^^^^^
This comes from the tool starting, so it's there.

> open: No such file or directory
  ^^^^^^^^^^
This is an error message from the tool, it could not open the device.


-- 
Regards,
Kai

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