Blkdiscard c

But last week I used the mmc tool to turn the user space into enhanced format. And since the default discard option of mkfs. Can you try erasing a smaller region of the device using the program below? Hi Arnd, Hmm, after one or two minutes I lost my patience. I did an strace, and the last few lines look like this:.


Post by Arnd Bergmann Can you try erasing a smaller region of the device Sure, this seems to work. I believe, mkfs. It would be helpful to understand where that kernel thread is stuck, but that is harder to do.

You should be able to erase up to 4GB at a time.

blkdiscard c

I had the exact same issue on an i. MX6 machine via amos with mkfs. When cross checking on a different i. I tried to understand how mkfs.

Theodore: Maybe you can help out here? The relevant line seems to be:. Can you try applying this series to see if it helps? Referring to this thread on the freescale forum:.

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Fabio Estevam from freescale suggested I report this to you. Are you aware of this issue? With above patches, the issue can be fixed. Is this sdhci-esdhc-imx. Are you using DMA mode?By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

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It only takes a minute to sign up. I would like to know how to delete a USB flash drive via the terminal if possible so data can't be recovered. You can follow it by an erase command designed for flash hardware, if you are on a recent enough distribution.

In theory, overwriting with zero with dd is just fine. However, due to how the internals of a flash drive are built, if you use a single overwrite pass, there may be several layers of data hidden behind the actual blocks that are still storing leftover information. Typically a part of flash storage is faulty, and is marked so during manufacturing.

There are also other bits that can go wrong becoming unchangeable, unsettable, or unclearablethese parts must be marked faulty as well during the lifetime.

This information is stored in a reserved space, on the same chips as your data. Flash storage is also internally organised in larger blocks, sometimes much larger than the filesystems working on the drive. A typical filesystem block size is 4KB, and the flash segments that can be erased in one go may range from 64KB to even several megabytes.

These large blocks can only be erased in whole, which resets all of the block to a known state all 1s or all 0s. Afterwards a data write can alter any of the bits change the default 1s into 0s where needed, or change the default 0s into 1sbut only once.

To change any of the bits back into the default, all of the segment needs to be erased again! So, when you want to change a 4KB block the filesystem is asked to change a single character in the middle of a filethe flash controller would need to read and buffer all 64KB of the old data, erase all of it, and write back the new contents.

This would be very slow, erasing segments is the slowest operation. Also, a segment can only erased by a limited times tens of thousands is typicalso if you make too many changes to a single file, that can quickly deteriorate the drive.

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But this is not how it's done. Intelligent flash controllers simply write the 4KB new data elsewhere, and make a note to redirect reads to this 4KB of data in the middle of the old block. They need some more space, that we can't see to store this information about redirects.

They also try to make sure that they go through all the accessible segments to store data, this is called wear levelling. This means that typically old data is still on the drive somewhere! If you just cleared all accessible blocks, all the hidden blocks still keep a quite recent version of the data. Whether this is accessible to an attacker you want your data to be protected from, is a different question.

If you have a recent enough distribution, and the USB drive is programmed to reveal that it is a flash drive, blkdiscard can use the underlying TRIM operation, which is the segment erase that we talked about above. It also has an additional flag to make sure that even the invisible hidden data is fully erased by the hardware:.

A secure discard is the same as a regular discard except that all copies of the discarded blocks that were possibly created by garbage collection must also be erased.We regularly and successfully use USB sticks for courses where participants bring their own notebooks. The big benefit is that students learn Linux, and realize that they can easily use the hardware they already own. Current notebook hardware is by far fast enough for data processing, structure solution and coot visualization.

Reclaim Freed Space Fails with error - BLKDISCARD: ioctl failed: operation not supported

What we found:. For performance, make sure that the big partitions are aligned to sector boundaries; gdisk default is sector boundaries - the default can be adjusted. Note: in the following, whenever you see the X in sdX, you must fill in the appropriate drive letter e. Not much to say about the installation of programs CCP4? You should also install the. Cheap USB sticks can hold a lot of data, but when it comes to writing small files which happens when used as the operating system diskthey are either slow from the beginning, or their write performance quickly degrades as soon as free space becomes low for the first time.

However, CrystalDiskMark does not capture the effect of degrading write performance, which can only be mitigated by TRIMming the media - a feature that few USB sticks support see below. The following is about performance and durability of the USB media. If you don't know what TRIM is and how it relates to flash media, read this. The suitability of the media makes a notable difference, in particular when the operating system or CCP4 is upgraded, or when e. The drawback of the "good" solution above is: from time to time e.

This naturally begs the question whether it wouldn't be much smarter to not use an USB adapter for microSD cards, but rather just use the SD adapter in a SD slot right away. That would have advantages - the SD card vanishes in most SD slots which is better than an USB stick sticking out, fstrim works, and possibly the SD controller is faster than the USB3 controller depending on the notebook model.

Thus, setup of a microSD card for booting in SD slot needs to be investigated. TRIMming informs the firmware about blocks of the filesystem that do not contain file data.

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The wiper. Since wiper. The same goes for blkdiscard.

blkdiscard c

This could be done after updating the software or data on the USB media, and before saving and compressing an image of it. Low-level formatting restores the write performance, and removes any sensitive information e. So use at your own risk:.

If you tried with --security-erase-enhanced, but the disk does not support it, then an error will occur and the disk will still be locked after the failed command, and you will not be able to write anything to it! If this happens, you can unlock it with.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

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Surely, somebody at some point in the past decided that 0x would get the physical sector size of a device and documented that somewhere.

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Where does this information come from and where can I find it? I am looking for a definitive, standardized source that states what argument types it should take and what its behavior should be for any driver that implements it. Specifically, I am asking because there appears to be a bug in blkdiscard in util-linux 2. So before I submit a patch, I need to determine, with absolute certainty, if the problem is that blkdiscard should be using a bit integer, or if the driver implementation in my kernel should be using a bit integer.

Edit 2: Since we're on the topic, the proposed patch presuming blkdiscard is incorrect is:. Applied to e.

I had been hesitant to mention the blkdiscard tool in both my mailing list post and the original version of this SO question specifically for this reason: I know what's in my kernel's source, it's already easy enough to modify blkdiscard to agree with the source, and this ended up distracting from the real question of "where is this documented?

So, as for the specifics, somebody more official than me has also stated that the BLKSSZGET ioctl takes an int, but the general question regarding documentation remained. He wrote :. I also asked about the use of "int" in general for public kernel APIs, his response is there although that is off-topic here. Answer: So, there you have it, the final answer is: The ioctl interfaces are specified by the kernel source itself; there is no document that the kernel adheres to.

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There is documentation to describe the kernel's implementations of various ioctls, but if there is a mismatch, it is an error in the documentation, not in the kernel.

Learn more. Ask Question. Asked 6 years, 5 months ago. Active 4 years, 1 month ago. Viewed 2k times. Roman C Jason C Jason C 32k 11 11 gold badges 89 89 silver badges bronze badges. I'm looking for a definitive specification of its behavior.

In particular, does it take a pointer to a or bit integer as a parameter and, more importantly, how do you know? Fair enough, I know 0 about it, thought that might help; will keep digging.

Given few probably know about this could you elaborate your Q a bit adding some context? Yeah I know you're an avid user over there, that's why I asked before starting the migration cycle ALL - please do not vote to close this Q, this is likely the best home for it, it will just waste time.

Let it bake here and hopefully someone that knows the answer or can provide guidance will get it. Did you post this on any of the linux kernel forums?

I'm thinking IRC might be another place to ask it. Active Oldest Votes. The answer to "where is this specified? If you look at the sources of util-linux v2.

The kernel source is the specification. That is man pages are descriptive, not perscriptive.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. Ask Ubuntu is a question and answer site for Ubuntu users and developers. It only takes a minute to sign up. I've just received my new SSD since the old one died. For testing purposes, my dealer put Windows on it, but I want to get rid of this and install Kubuntu on it.

It does not have to be a "secure wipe", I just need the empty the disk in the most healthy way. I've seen the answer How to enable TRIMbut it looks like it's suited for clearing empty blocks, not wiping the disk.

blkdiscard c

From its manual page:. You should use the drive's security erase feature. Make sure the drive Security is not frozen. If it is, it may help to suspend and resume the computer. Set a User Password this password is cleared too, the exact choice does not matter. This is useful for solid-state drivers SSDs and thinly-provisioned storage. Unlike fstrim 8 this command is used directly on the block device. By default, blkdiscard will discard all blocks on the device.

SDカードのSecure Eraseの方法 (Linux向け)

Options may be used to modify this behavior based on range or size, as explained below. The command is there since Ubuntu If you don't need a secure wipe, why don't you just install kubuntu using the options to 'use entire disk' and the equivalent of 'quick format' can't remember the exact terminology right now. That way you ditch the file allocation table and the drive is effectively emptied for overwriting.

You don't actually need to empty it. If the drive has a Linux filestem on it, you can use fstrim.A vulnerability classified as problematic was found in Google Android 9.

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As an impact it is known to affect confidentiality. The advisory is shared for download at source. The attack needs to be approached locally. No form of authentication is required for a successful exploitation.

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There are known technical details, but no exploit is available. The vulnerability was handled as a non-public zero-day exploit for at least 9 days. The entries, and are pretty similar.

The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system. Our analysts are monitoring exploit markets and are in contact with vulnerability brokers.

The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack. Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time.

A high score indicates an elevated risk to be targeted for this vulnerability.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. It only takes a minute to sign up. I need to securely erase harddisks from time to time and have used a variety of tools to do this:.

Is there a "good enough" approach to achieve that any data on the disk is made unusable in a timely fashion? Overwriting superblocks and a couple of strategically important blocks or somesuch? The disks both, spinning and ssd come from donated computers and will be used to install Linux-Desktops on them afterwards, handed out to people who can't afford to buy a computer, but need one. The disks of the donated computers will usually not have been encrypted.

And sometimes donors don't even think of deleting files beforehand. From the answers that have come in so far, it seems there is no cutting corners. My best bet is probably setting up a lab-computer to erase multiple disks at once. One more reason to ask big companies for donations Overwriting the superblock or partition table just makes it inconvenient to reconstruct the data, which is obviously still there if you just do a hex dump.

Hard disks have a built-in erasing feature: ATA Secure Erasewhich you can activate using hdparm :. Since this is a built-in feature, it is unlikely that you'll find a faster method that actually offers real erasure. It's up to you, though, to determine whether it meets your level of paranoia.

Alternatively, use the disk with full-disk encryption, then just throw away the key when you want to dispose of the data. Potentially unpopular answer: Put up with the time to completely wipe the disks securely.

You've accepted donation hardware from various sources, and made promises that their data will be securely erased. So you have to do as you promised and securely erase the disks. If I was a donor and I found that you weren't keeping your promises, I'd not give you any more hardware in the future.

To make your DBAN runs more convenient, do you generally remove drives from hosts? If so, have a fairly low-power desktop aside with multiple SATA ports. Then leave the machine running until the last one is complete.

Second, do you have a workflow of storing donations then processing them? Or do you accept the hardware in, test it, wipe it and then store the items for use?

I'd suggest you make a pipeline that works for you, and make DBAN a stage in that pipeline. So when you pull a machine from the store, its already wiped as well as known-good. The only question is how close to that you can get. I haven't tried this, but from a quick read, you could try blkdiscard. This will just send simple commands to the drive and should be very fast, but I have not found any guarantee that the data in the blocks will be erased.

There are some hints though. For a very brief time, the data could still reside on the flash internally. However, after the TRIM command is issued and garbage collection has taken place, it's highly unlikely that even a forensic scientist would be able to recover the data. I would obviously not trust this for serious business, but since your requirement is "good enough", it might be a viable option.

Presumably it only works on SSDs as well, which may be a more serious hurdle if you're dealing with old donated computers. There is one scenario when you can rewrite an only a small part of the disk, and most people will consider it save. If a drive was encrypted overwriting the encryption header a place where the encryption key is stored should make it impossible to recover.

But there is another problem - the SSD can potentially keep header data the random data that was used to overwrite header can be saved to other cells.

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