[CLUE-Tech] Converting ext2 to ext3

[Sean Reifschneider]

On Sat, Jul 20, 2002 at 07:03:00PM -0600, Jeffery C. Cann wrote:
>On Thursday 18 July 2002 11:54 am, you wrote:
>>  I believe the only on-disk difference between 2 and 3 is the journal, and 
>> an old ext2 kernel will just ignore the journal, with no ill-effects.  All 
>> of the journaling magic must live in the kernel driver.
>
>I think you are correct.  The only difference is the journaling.  Ext3 
>filesystem structure is the same as ext2:

Ext3 can also have B+Tree structured directories, which ext2 doesn't know
about.  However, you have to explicitly convert the directories from
old-style to B+Tree, so it won't happen unless you ask for it.  ext2 will
ignore the directory if it doesn't understand it.

It's true that ext2 can use ext3 file-systems, but only if they've been
cleanly unmounted.  If the journal contains transactions that need to be
replayed, ext2 will not mount it (at least not read/write, maybe ro).

Sean
-- 
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Sean Reifschneider, Inimitably Superfluous <jafo at tummy.com>
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