Open a file in a specific block on Linux

Question

For debugging purposes, I want to open the file on a specific predefined block. For example, if I suspect that a particular block is damaged, I want to write and read it, and I would rather do it in user mode while the section is installed.

Is there a way to say Linux: "Hey, open this new file on block 4579 if it is free."

Yes, I can edit the block device directly, but this can cause the file system to crash if a disk is installed.

General answers are welcome, but even the answer for ext filesystems families is good enough.

Answer 1

For example, if I suspect that a particular block is damaged, I want to write and read it ... Is there a way to tell Linux: "Hey, open this new file on block 4579 if it is free."

Yes, you can use the basic block device as a file and search for it in this file. This seems appropriate given your “debugging” option. Please note that writing to this block may destroy the integrity of the file system above (even for writing just read content).

Otherwise, no, file systems are designed to hide , often mask the layout of the device real geometry and as such there is no such mechanism to give clues about where the file should be created.