Re: (reiserfs) Re: LVM / Filesystems / High availability

Michael Marxmeier (mike@msede.com)
Wed, 24 Jun 1998 03:59:35 +0200

Theodore Y. Ts'o wrote:
> The plan is to eventually add kernel support for moving the location of
> data blocks of a file, and given an inode number and all of the
> directories in which that inode appears, move an inode to another
> location on disk. This would allow a user-mode program to be able to do
> on-line resizing at some point in the future.
>
> This will be a ways off, but theoretically it really isn't all that hard
> to do. (As always, the devil is in the details. :-)

For example locking the fs without making it effectively unusable
(this is about on-line resizing):
- negotiating with LVM about PEs which should be freed
- the fs may no longer use that PEs for allocation
- in case an inode must be moved
- how to find all directories an inode is in on a life fs w/o
all the possible races (on a big fs)
- how to deal with open files when inode needs to be moved
- how to do it safe so fsck is able to cleanup
- some ext2 metadata must be aligned (block/cylinder groups)?

Just wondering if this is achievable with ext2?

Michael

-- 
Michael Marxmeier           Marxmeier Software GmbH
E-Mail: mike@msede.com      Besenbruchstrasse 9
Voice : +49 202 2431440     42285 Wuppertal, Germany
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