linux-ext4 - Directio flags in dd command causes file corruption on ext4 filesystem

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Message-ID: <CABx-mUmNtkpUJCNRWBieu0B0vgwB5QyoLLmrbkKr6Qo0X7Zx8A@mail.gmail.com>
Date:	Fri, 6 Feb 2015 00:46:57 +0530
From:	Ramesh M <rameshandram@...il.com>
To:	linux-ext4@...r.kernel.org
Subject: Directio flags in dd command causes file corruption on ext4 filesystem

Hello All,

I am using linux 3.3.8 kernel on AP and trying to copy  5200  bytes
of data from AP to USB disk
( /dev/sda1 -contains ext4 ) using directio method .

For  example
  mount  /dev/sda1 /mnt/usb-ext4/

   dd if=inptu.data  of=/mnt/usb-ext4/output.data bs=4096
conv=notrunc oflag=append,direct

the input.data  file contains know pattern for example 0xaa55. and
after writing this file from AP to USB disk, randomly  i observed
that  the output.data  file was corrupted (instead of 0xaa55, zero is
written in the middle of the output file ) .

is there any patches already available to fix this issue ?

Thanks in advance for your help.

Regards
Ramesh
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