linux-ext4 - [PATCH] extend e2fsprogs functionality to add EXT2_FLAG

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Date:	Fri, 08 Jan 2010 10:36:50 +0100
From:	Michal Novotny <minovotn@...hat.com>
To:	linux-ext4@...r.kernel.org
Subject: [PATCH] extend e2fsprogs functionality to add EXT2_FLAG_DIRECT option

This patch extends functionality of e{2|4}fsprogs to add 
EXT2_FLAG_DIRECT flag to be passed to ext2fs_open2() function. This 
internally calls open() function with O_DIRECT and handles the memory 
alignment for both read and write operations.
In some cases direct access to devices is necessary and that was the 
main reason for this patch to be done.

The main reason why this was done is that pygrub (used by xen 
virtualization user-space package, it's a python version of grub for 
paravirtualized guests) sometimes uses outdated version of grub.conf 
file. Modifications to xen package were *not* enough because e2fsprogs 
doesn't open the files directly. That's why I added EXT2_FLAG_DIRECT 
support to make read/write operations work directly when passed. It's 
been tested with pygrub like mentioned above for read operation and it's 
working fine.

Signed-off-by: Michal Novotny <minovotn@...hat.com>

View attachment "mig-e4fsprogs-direct-read-write.patch" of type "text/x-patch" (5619 bytes)