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From: Bernd Petrovitsch <>
To: Bharath Vedartham <>,
Subject: Re: Overwriting copy functionality in filesystem
Date: Sat, 23 Mar 2019 20:03:20 +0100
Message-ID: <> (raw)
In-Reply-To: <20190323165945.GA13199@bharath12345-Inspiron-5559>

Hi all!

On 23/03/2019 17:59, Bharath Vedartham wrote:
> I was wondering how we can overwrite the copy functionality while
> writing our own filesystem in linux. 
> VFS does not offer any sort of API for copy. I think it calls create and


> write when we execute the copy the file/dir.
> I am interested in overwriting the way copy happens in my
> filesystem(which I am writing for fun :p). 
> Any ideas?

strace a "cp" and see which system calls are used.
Look into the source code and see how it's implemented.

There is actually more than one method but the usual (while simplest,
most versatile and probably fastest) method used is: open source and
destination files, read from the source, write into the destination
until EOF.

Bernd Petrovitsch                  Email :
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Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-23 16:59 Bharath Vedartham
2019-03-23 19:01 ` Valdis Klētnieks
2019-03-24 13:18   ` Bharath Vedartham
2019-03-24 14:06     ` Valdis Klētnieks
2019-03-28 18:30       ` Bharath Vedartham
2019-03-28 20:07         ` Valdis Klētnieks
2019-03-23 19:03 ` Bernd Petrovitsch [this message]
2019-03-24 13:21   ` Bharath Vedartham
2019-03-23 19:05 ` Greg KH

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