Hello, I'll inline the answers... Am 21.02.2017 um 02:34 schrieb 박마루한:
Hello, When I activate a volume using cryptsetup, I have the following: 1. Original image file 2. Block device from the image file 3. Image file that was created using cryptsetup
No. cryptsetup sets up a crypto mapping consisting of a pseudo-blockdevice and operates on a blockdevice. It transforms writes to the pseudoblockdevice to writes of encrypted data onto the backing blockdevice, while a read operation will read from the backing blockdevice, decipher the encrypted content and then deliver it to the read() that was issued to the cleartext (pseudo)device.
Then, you would make another block device from number 3.
No, since 3 is a blockdevice already.
Now, here's where I am confused. I assume when you mount and write to the block device from the last step. I assume that this will cause writes to the file in number 3, which then cause writes to number 2 and 1. But when you read, do you just simply read from number 3? Or are you actually reading from number 1?
You usually read/write to and from the pseudoblockdevice created by cryptsetup (the dmcrypt target, i.e. /dev/mapper/<cryptotargetname>), which will in turn read from/write to the backing blockdevice. The backing-device can also be called lower-device in terms of looking at a stack, when it comes to Linux' storage system.
Regards -Sven _______________________________________________ dm-crypt mailing list dm-crypt@xxxxxxxx http://www.saout.de/mailman/listinfo/dm-crypt
