Cannot format USB drive

ralph_hellgrind · 2016-09-26 12:39:43

Hello, I have a 16 GB USB 3.0 flashdrive and I want to format it but whenever I try to do so, I get the following output:

cannot open /dev/sdb: Read-only file system

I have tried commands like 'dd', 'fdisk', cfdisk', 'sfdisk', 'mkfs.vfat' but I always get the same output.

What do I do to get this corrected. [I have unmounted the USB drive before trying the above mentioned commands to format it, but to no avail].

Thanks!

WorMzy · 2016-09-26 12:45:58

Does the USB stick have a hardware switch that locks it to read-only mode?

If not, please post the output of

mount | grep "on /dev"

as well as the journal from an affected session.

ralph_hellgrind · 2016-09-27 03:13:55

There is no hardware switch to lock it into read only mode.

The output of

mount | grep "on /dev"

dev on /dev type devtmpfs (rw,nosuid,relatime,size=4035504k,nr_inodes=1008876,mode=755)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
mqueue on /dev/mqueue type mqueue (rw,relatime)
hugetlbfs on /dev/hugepages type hugetlbfs (rw,relatime)

And the output of

fdisk -l

Disk /dev/sdb: 14.5 GiB, 15504900096 bytes, 30283008 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x00000000

Thanks!

ayekat · 2016-09-27 06:36:10

Is the read-only flag set on the device?

hdparm -r /dev/sdb

If yes, you can try to unset it with

hdparm -r0 /dev/sdb

and then see whether you can write to the device.

But if it still fails, something might be broken there...

Anon1234 · 2016-09-27 12:54:58

Another newbie here, so not sure if this will help

But what file system are you trying to format in? If for example it is NTFS, have you installed the ntfs-3g package?

I had a similar issue writing to a USB stick that was only mounting in read only mode

headkase · 2016-09-27 15:15:05

Sanity check, you are trying to format the drive with root privileges right? Like either in a su'd console or with the sudo command?

ralph_hellgrind · 2016-10-01 07:32:58

Yes, I am trying to format it by being root user (or su).
I am trying to format it with FAT filesystem and I am using the command:

mkfs.vfat

I tried using 'hdparm' as follows:

# hdparm -r0 /dev/sdb

/dev/sdb:
setting readonly to 0 (off)
readonly = 0 (off)

But when I try to format it I again get the error:

Could not open /dev/sdb: Read-only file system

Thanks!

ukhippo · 2016-10-01 11:47:48

Sanity check: you are trying to format the partition (presumably /dev/sdb1) and not the device (/dev/sdb)?

If so, can you delete and recreate the partition?

ralph_hellgrind · 2016-10-01 14:18:57

There is no '/dev/sdbx'. It only shows '/dev/sdb' when I try to use the 'fdisk -l' command.
The modified output of 'fdisk -l' is:

Disk /dev/sdb: 14.5 GiB, 15504900096 bytes, 30283008 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x00000000

I cannot delete and recreate the partition. When I try to do so:

fdisk /dev/sdb

It gives the output-

fdisk: cannot open /dev/sdb: Read-only file system

Thanks

Lone_Wolf · 2016-10-01 14:59:17

remove the usb drive, wait a few seconds then plug it in again.

post dmesg | tail -n 25 , partx -s /dev/sdb and lsblk output .

ralph_hellgrind · 2016-10-02 06:21:52

The outputs of 'dmesg', 'partx' and 'lsblk' are as follows:

tail -n 25
[ 43.213293] fuse init (API version 7.25)
[ 165.433200] usb 1-3: new high-speed USB device number 5 using xhci_hcd
[ 165.670015] usb-storage 1-3:1.0: USB Mass Storage device detected
[ 165.673509] scsi host4: usb-storage 1-3:1.0
[ 165.673654] usbcore: registered new interface driver usb-storage
[ 165.910520] usbcore: registered new interface driver uas
[ 166.677402] scsi 4:0:0:0: Direct-Access SanDisk SanDisk Ultra PMAP PQ: 0 ANSI: 6
[ 166.677937] sd 4:0:0:0: [sdb] 30283008 512-byte logical blocks: (15.5 GB/14.4 GiB)
[ 166.678136] sd 4:0:0:0: [sdb] Write Protect is off
[ 166.678140] sd 4:0:0:0: [sdb] Mode Sense: 2b 00 00 08
[ 166.678345] sd 4:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
[ 166.961737] sdb:
[ 166.962365] sd 4:0:0:0: [sdb] Write Protect is on
[ 166.962371] sd 4:0:0:0: [sdb] Mode Sense: 2b 00 80 08
[ 166.962567] sd 4:0:0:0: [sdb] Attached SCSI removable disk

# partx -s /dev/sdb
partx: /dev/sdb: failed to read partition table

# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 931.5G 0 disk
├─sda1 8:1 0 30G 0 part /
├─sda2 8:2 0 8G 0 part [SWAP]
└─sda3 8:3 0 893.5G 0 part /home
sdb 8:16 1 14.5G 1 disk /run/media/<user>/Movies
sr0 11:0 1 1024M 0 rom

Thanks!

philo · 2016-10-02 09:31:04

Please use code, not bold.

ukhippo · 2016-10-02 12:00:18

1. As philo says, please use “code” tags, not “b” tags, when posting program output. It preserves formatting and makes it easier to read.

2. You mount disk partitions, not disks - so why is /dev/sdb mounted?
I'm guessing you've got some sort of misconfigured automounter.
Correct your automounter to not mount /dev/sdb and then unmount the disk.
Can you now run fdisk/partx? If not, try replugging.

ralph_hellgrind · 2016-10-03 04:08:01

Ok, will use 'code' tag and not 'b' tag. Sorry.

When mounting other USB drives, the OS mounts them correctly. In case of this particular USB drive, this is happening. When I plug in the device, it opens the drive and I can see the contents in it. I can copy it's contents but cannot write to it.

I tried unmounting the drive and manually mounting it to a folder named 'Mount_USB' but I am getting the following error:

# mkdir Mount_USB
# mount /dev/sdb Mount_USB/
mount: /dev/sdb is write-protected, mounting read-only

I used this USB drive in a laptop where a WD external encrypted drive was also plugged in and it's (WD external HDD) contents were unlocked using the GUI of WD's drive unlocking software. I think that this error is occurring after this incident. Do you think this has got something to do with the errors I am getting?

seth · 2016-10-03 06:14:56

Formatting a mounted device is a bad idea, so always ensure to unmount it first.

The device is considered write protected.
This is either a misinterpretation of the usb stack in the kernel or the device actually is write only.
1. Try another USB slot. Try all you have and avoid any adapters/readers
2. Can you write into it from a windows box?

In case of 2:

Check file permissions "stat /dev/sdb" and try to alter them "chmod +w /dev/sdb" (notice that sdb must of course match the actually troubling device and not some other usb key attached ;-)
Then try again.

In case it's a kernel bug, this might (or not) be due to some FS junk in the first sector of the device. You might be better of creating a partition table (using either fdisk or cfdisk)

ayekat · 2016-10-03 06:30:38

Generally, I don't think that the issue is caused by the FS being directly on /dev/sdX rather than a partition, or the FS not having been unmounted properly, or whatever else...
If even fdisk (and similar) fail, it becomes more of a hardware issue.

ralph_hellgrind wrote:

I tried using 'hdparm' as follows:

# hdparm -r0 /dev/sdb

/dev/sdb:
 setting readonly to 0 (off)
 readonly      =  0 (off)

What was the output of `hdparm -r` before you explicitly turned off read-only mode? If it was on, does it turn back on when you reconnect it?

Last edited by ayekat (2016-10-03 06:30:57)

ralph_hellgrind · 2016-10-05 17:42:32

chmod +w /dev/sdb

did not work.

hdparm -r /dev/sdb 

/dev/sdb:
 readonly      =  1 (on)

hdparm /dev/sdb 

/dev/sdb:
SG_IO: bad/missing sense data, sb[]:  70 00 05 00 00 00 00 0a 00 00 00 00 20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 multcount     =  0 (off)
 readonly      =  1 (on)
 readahead     = 256 (on)
 geometry      = 14786/64/32, sectors = 30283008, start = 0

Thanks

Arch Linux

#1 2016-09-26 12:39:43

Cannot format USB drive

#2 2016-09-26 12:45:58

Re: Cannot format USB drive

#3 2016-09-27 03:13:55

Re: Cannot format USB drive

#4 2016-09-27 06:36:10

Re: Cannot format USB drive

#5 2016-09-27 12:54:58

Re: Cannot format USB drive

#6 2016-09-27 15:15:05

Re: Cannot format USB drive

#7 2016-10-01 07:32:58

Re: Cannot format USB drive

#8 2016-10-01 11:47:48

Re: Cannot format USB drive

#9 2016-10-01 14:18:57

Re: Cannot format USB drive

#10 2016-10-01 14:59:17

Re: Cannot format USB drive

#11 2016-10-02 06:21:52

Re: Cannot format USB drive

#12 2016-10-02 09:31:04

Re: Cannot format USB drive

#13 2016-10-02 12:00:18

Re: Cannot format USB drive

#14 2016-10-03 04:08:01

Re: Cannot format USB drive

#15 2016-10-03 06:14:56

Re: Cannot format USB drive

#16 2016-10-03 06:30:38

Re: Cannot format USB drive

#17 2016-10-05 17:42:32

Re: Cannot format USB drive

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