Re: Write protect access on USB port
Amit a écrit :
>
> However, this still poses a problem. Check out the following case:
>
> 1. Plug in a USB drive with an ext4 filesystem.
> 2. Set the readonly flag using blockdev.
> 3. Compute the checksum on this block device.
> 4. Mount the ext4 filesytem and then unmount it without doing anything.
> 5. Compute the checksum on the block device (checksum does not match).
>
> The ext4 filesystem still updates the journal on the device and changes
> the whole checksum.
That's because the filesystem is on a partition, not on the whole disk,
an the partition block device is still read-write.
The read-only flag must be set on the disk and all its partitions. I
guess udev can do this.
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