From: Carlos Maiolino <cmaiolino@redhat.com>
Subject: Still about ext2/ext3 mount options while using ext4.ko driver
Date: Mon, 9 Dec 2013 19:25:31 -0200
Message-ID: <20131209212531.GB4296@orion.maiolino.org>
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To: linux-ext4@vger.kernel.org
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Sender: linux-ext4-owner@vger.kernel.org

Hi guys,

Ted released some months ago a patch to deny some options to be used by ext4.ko
driver while mounting an ext2/3 filesystem.

But, there are still some mount options that IMHO needs a review of what should
and shouldn't be allowed while using ext4 to mount ex2/3 filesystems.

These are the options:

inode_readahead_blks=32 # ext2/3 might get some benefits from it

stripe=4 	 # Feasible to all extX IMHO

max_batch_time=5 #I'm not sure ir this has any gain for ext2 and if it might
		  work well with ext3, any comments?

min_batch_time=5 #same as above

journal_ioprio=5 #doesn't make sense for ext2, but might be useful for ext3 FS?!

auto_da_alloc    #ext4 only

noauto_da_alloc  #same as above

discard		 #ex2 shouldn't be allowed to use it ?!

nodiscard	 #same as above

block_validity   #ext4 and debugging purposes only, should be off for ext2/3 too

noblock_validity #same as above

i_version  # I believe this is only valid for Ext4 

journal=11 #doesn't make sense for ext2

barrier=1 #doesn't make sense for ext2

barrier #doesn't make sense for ext2

nobarrier #doesn't make sense for ext2

commit=5  #doesn't make sense for ext2

abort  #call ext4_abort(), devel usage only, and it fails to put ext2 FS on RO,
       if this should be kept enabled, I can look why ext2 keep RW after its use


Let me know what you guys think.

Cheers

-- 
Carlos