mounting without -o loop
I have written a dummy (ram disk) block device driver for linux kernel. When the driver is loaded, I can see it as /dev/mybd.
I can successfully transfer data onto it using dd command, compare the copie开发者_如何学God data successfully.
The problem is that when I create ext2/3 filesystem on it, I have to use -o loop option with the mount command. Otherwise mount fails with following result:
mount: wrong fs type, bad option, bad superblock on mybd, missing codepage or helper program, or other error
What could be the problem? Please help.
Thanks.
Hmm, if it works with -o loop
and doesn't work without, then I have bad news for you: your "device" is actually just a plain file in /dev. What does ls -l /dev/mybd
show? If its filesize is non-zero, it's a regular file, and has nothing to do with your driver.
Use mknod
to create the device file yourself if needed.
I see you're starting over again. As a quick note about your previous attempt, did you make sure your device appeared in /dev as a block device and not a character one?
Create a filesytem on the device before mounting it:
mkfs -t ext2 /dev/mybd
or
mke2fs /dev/mybd
The loop device is used to mount block special files on the linux filesystem emulating them as block devices. Hence, the mount throws error.
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