<br><br><div class="gmail_quote">On Tue, Nov 8, 2011 at 5:26 PM, Dan Luedtke <span dir="ltr"><<a href="mailto:maildanrl@googlemail.com">maildanrl@googlemail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Hallo,<br>
<br>
On Tue, Nov 8, 2011 at 12:27 PM, Stephen Gream <<a href="mailto:poisonthemon@gmail.com">poisonthemon@gmail.com</a>> wrote:<br>
> Once you have the device registered (on /sys or /dev), register a read<br>
> callback on the file and use copy_to_user to output the data<br>
<br>
I read that article you referred to, but I don't think it addresses my<br>
problem, as I may have been more clear on what I want to achieve<br>
before. Sorry for that!<br>
I want to eventually implement a file system, and therefore I am<br>
studying the kernel sources to get an idea about all that.<br>
<br>
Here is my general understanding on how thinks may work :)<br>
<br>
virtual file system (VFS) <-[1]-> my file system implementation<br>
<-[2]-> a block device<br>
<br>
As I understood, all these subsystems are running in kernel mode.<br>
<br>
For [1] I read vfs.txt and learned about the VFS-API<br>
For [2] I have no idea where I can find the API documentation, however<br>
there were some hints on the book "Linux Driver Development" from<br>
O'Reilly in chapter "block devices". Nothing really helpful, as they<br>
were talking about registering new block devices. I want to use<br>
already present devices where I expect my filesystem to be present on.<br>
To check that, I have to read the first 512 bytes.<br>
<br>
The userspace implementation I was talking about previously is<br>
something like a mkfs.myfilesystem, that's why i referred to fopen()<br>
there.<br>
<br>
Thank you!<br>
<br>
Greetings,<br>
<div><div></div><div class="h5"><br>
Dan<br>
--<br>
Dan Luedtke<br>
<a href="http://www.danrl.de" target="_blank">http://www.danrl.de</a><br>
<br>
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</div></div></blockquote></div>Dan,<br><br>You need to look at other block-based file systems in the kernel sources in fs dir for examples and understand how they do it.<br><br>Regards,<br>Rohan Puri<br>