Re: [gentoo-user] USB crucial file recovery

[J. Roeleveld]

On August 29, 2016 3:24:18 AM GMT+02:00, Grant <emailgrant@×××××.com> wrote:
>>> I have a USB stick with a crucial file on it (and only an old backup
>>> elsewhere).  It's formatted NTFS because I wanted to be able to open
>>> the file on various Gentoo systems and my research indicated that
>NTFS
>>> was the best solution.
>>>
>>> I decided to copy a 10GB file from a USB hard disk directly to the
>USB
>>> stick this morning and I ran into errors so I canceled the operation
>>> and now the file manager (thunar) has been stuck for well over an
>hour
>>> and I'm getting errors like these over and over:
>>>
>>> [ 2794.535814] Buffer I/O error on dev sdc1, logical block 2134893,
>>> lost async page write
>>> [ 2794.535819] Buffer I/O error on dev sdc1, logical block 2134894,
>>> lost async page write
>>> [ 2794.535822] Buffer I/O error on dev sdc1, logical block 2134895,
>>> lost async page write
>>> [ 2794.535824] Buffer I/O error on dev sdc1, logical block 2134896,
>>> lost async page write
>>> [ 2794.535826] Buffer I/O error on dev sdc1, logical block 2134897,
>>> lost async page write
>>> [ 2794.535828] Buffer I/O error on dev sdc1, logical block 2134898,
>>> lost async page write
>>> [ 2794.535830] Buffer I/O error on dev sdc1, logical block 2134899,
>>> lost async page write
>>> [ 2794.535832] Buffer I/O error on dev sdc1, logical block 2134900,
>>> lost async page write
>>> [ 2794.535835] Buffer I/O error on dev sdc1, logical block 2134901,
>>> lost async page write
>>> [ 2794.535837] Buffer I/O error on dev sdc1, logical block 2134902,
>>> lost async page write
>>> [ 2842.568843] sd 9:0:0:0: [sdc] tag#0 FAILED Result:
>>> hostbyte=DID_ERROR driverbyte=DRIVER_SENSE
>>> [ 2842.568849] sd 9:0:0:0: [sdc] tag#0 Sense Key : Hardware Error
>[current]
>>> [ 2842.568852] sd 9:0:0:0: [sdc] tag#0 Add. Sense: No additional
>sense
>>> information
>>> [ 2842.568857] sd 9:0:0:0: [sdc] tag#0 CDB: Write(10) 2a 00 01 04 a4
>>> 58 00 00 f0 00
>>> [ 2842.568859] blk_update_request: I/O error, dev sdc, sector
>17081432
>>> [ 2842.568862] buffer_io_error: 20 callbacks suppressed
>>>
>>> nmon says sdc is 100% busy but doesn't show any reading or writing.
>I
>>> once pulled the USB stick in a situation like this and I ended up
>>> having to reformat it which I need to avoid this time since the file
>>> is crucial.  What should I do?
>>>
>>> - Grant
>>
>> Whatever you do, do NOT try to unplug the USB you were writing to
>unless you
>> first manage to successfully unmount it.  If you do pull the USB
>stick
>> regardless of its current I/O state you will likely corrupt whatever
>file you
>> were writing onto, or potentially more.
>>
>> You could well have a hardware failure here, which manifested itself
>during
>> your copying operation.  Things you could try:
>>
>> Run lsof to find out which process is trying to access the USB fs and
>kill it.
>> Then see if you can remount it read-only.
>>
>> Run dd, dcfldd, ddrescue to make an image of the complete USB stick
>on your
>> hard drive and then try to recover any lost files with testdisk.
>>
>> Use any low level recovery tools the manufacturer may offer - they
>will likely
>> require MSWindows.
>>
>> Shut down your OS and disconnect the USB stick, then reboot and try
>again to
>> access it, although I would first create an image of the device using
>any of
>> the above tools.
>
>
>dd errored and lsof returned no output at all so I tried to reboot but
>even that hung after the first 2 lines of output so I did a hard reset
>after waiting an hour or so.  Once it came back up I tried to do 'dd
>if=/dev/sdb1 of=usbstick' but I got this after awhile:
>
>dd: error reading ‘/dev/sdb1’: Input/output error
>16937216+0 records in
>16937216+0 records out
>8671854592 bytes (8.7 GB) copied, 230.107 s, 37.7 MB/s
>
>It's a 64GB USB stick.  dmesg says:
>
>[  744.729873] sd 8:0:0:0: [sdb] tag#0 FAILED Result: hostbyte=DID_OK
>driverbyte=DRIVER_SENSE
>[  744.729879] sd 8:0:0:0: [sdb] tag#0 Sense Key : Medium Error
>[current]
>[  744.729883] sd 8:0:0:0: [sdb] tag#0 Add. Sense: Unrecovered read
>error
>[  744.729886] sd 8:0:0:0: [sdb] tag#0 CDB: Read(10) 28 00 01 02 78 e0
>00 00 f0 00
>[  744.729889] blk_update_request: critical medium error, dev sdb,
>sector 16939232
>[  744.763468] sd 8:0:0:0: [sdb] tag#0 FAILED Result: hostbyte=DID_OK
>driverbyte=DRIVER_SENSE
>[  744.763472] sd 8:0:0:0: [sdb] tag#0 Sense Key : Medium Error
>[current]
>[  744.763474] sd 8:0:0:0: [sdb] tag#0 Add. Sense: Unrecovered read
>error
>[  744.763478] sd 8:0:0:0: [sdb] tag#0 CDB: Read(10) 28 00 01 02 79 00
>00 00 04 00
>[  744.763480] blk_update_request: critical medium error, dev sdb,
>sector 16939264
>[  744.763482] Buffer I/O error on dev sdb1, logical block 4234304,
>async page read
>[  744.786743] sd 8:0:0:0: [sdb] tag#0 FAILED Result: hostbyte=DID_OK
>driverbyte=DRIVER_SENSE
>[  744.786747] sd 8:0:0:0: [sdb] tag#0 Sense Key : Medium Error
>[current]
>[  744.786750] sd 8:0:0:0: [sdb] tag#0 Add. Sense: Unrecovered read
>error
>[  744.786753] sd 8:0:0:0: [sdb] tag#0 CDB: Read(10) 28 00 01 02 79 04
>00 00 04 00
>[  744.786755] blk_update_request: critical medium error, dev sdb,
>sector 16939268
>[  744.786758] Buffer I/O error on dev sdb1, logical block 4234305,
>async page read
>
>I haven't tried to mount it yet.  Any suggestions?
>
>- Grant

Try ddrescue.
It tries to skip the really bad parts.

Then try data recovery on copies of the resulting image file.

--
Joost
-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.