e2find: new ext2/3/4 tool for fast directory entry iterations

Vincent Caron vcaron at bearstech.com
Tue Aug 23 09:14:46 UTC 2016


  thanks for your feedback !

On 21/08/16 13:31, Bodo Thiesen wrote:
> For an ext2 fs with journal, you could try interpreting the journal and
> fixup your cache to bring it up to date like this:
> 1. Get a copy of the journal
> 2. Read the blocks you're interested in (i.e. do the normal traversing
>    step).
> 	-> from time to time, get a new copy of the journal, check what
> 	changed, process the changes. This also means, you need to keep
> 	some meta data about when and where you got your data from, so you
> 	can actually fixup stuff. Remember: While traversing, you can read
> 	any kind of trash.
> 3. Upon completion of 2. get a final copy of the journal to bring
>    your cache up-to-date.

  I see. However libe2fs has some support to create journals but does
not seem to have an API to read and interpret the journal inode data,
that would be much more complex to implement for me.

> I leave the details to you're implementation skills, since I don't know
> what your strategies in e2find are.

  e2find does not track any file<->block relationship, which I guess is
needed in my case to map back journal data to files, and I would meed
more I/O and way more memory to implement this. I feel I'm going to give
up on the journal idea and add a clear warning of this limitation of
e2find in its documentation ...

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