writes to unmounted partitions

writes to unmounted partitions

[Prashant Shah]

Hi,

I am confused on how does Linux kernel handle writes done directly to
the /dev/sda3 partitions which is not even mounted.

Is the kernel even aware of such writes, does it go though the request
queue, I/O scheduler, etc ? Is it possible to monitor such writes ?

Regards.

writes to unmounted partitions

[Prashant Shah]

Hi Asutosh,

> It does a raw read and write. The I/O operations go through request queue
> and I/O scheduler but not through any file-system. The writes and reads
> would start from the offset that is provided in the read and write call.
>
>>> Is it possible to monitor such writes ?
> Please explain what you mean by monitor ?

I meant how can I track the reads/writes happening to the unmounted
partitions from within a kernel module ? I can do that easily when the
partition is mounted.

Regards.

writes to unmounted partitions

[Mulyadi Santosa]

Hi..

On Sat, Nov 17, 2012 at 5:29 PM, Prashant Shah <pshah.mumbai@gmail.com> wrote:
> Hi,
>
> I am confused on how does Linux kernel handle writes done directly to
> the /dev/sda3 partitions which is not even mounted.
>
> Is the kernel even aware of such writes, does it go though the request
> queue, I/O scheduler, etc ? Is it possible to monitor such writes ?

IIRC, blktrace is designed to monitor such I/O events at the block
level. Try it :)

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com

writes to unmounted partitions

[Prashant Shah]

Hi,

> IIRC, blktrace is designed to monitor such I/O events at the block
> level. Try it :)

Ok I will try that. I was thinking about it and something that made it
clear to me is : "Since its writing to the actual disk through
/dev/sdaX the kernel knows about it, since its the one that is
translating the writes from the /dev/sdaX file to the actual disk"

Regards.