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    SubjectRe: Back to the future.
    Kyle Moffett wrote:
    > On May 03, 2007, at 11:10:47, Pavel Machek wrote:
    >> How mature is freezing filesystems -- will it work on at least ext2/3
    >> and vfat?
    >
    > I'm pretty sure it works on ext2/3 and xfs and possibly others, I don't
    > know either way about VFAT though. Essentially the "freeze" part
    > involves telling the filesystem to sync all data, flush the journal, and
    > mark the filesystem clean. The intent under dm/LVM was to allow you to
    > make snapshots without having to fsck the just-created snapshot before
    > you mounted it.
    >
    >> What happens if you try to boot and filesystems are frozen from
    >> previous run?
    >
    > If you're just doing a fresh boot then the filesystem is already clean
    > due to the dm freeze and so it mounts up normally. All you need to do
    > then is have a little startup script which purges the saved image before
    > you fsck or remount things read-write since either case means the image
    > is no longer safe to resume.

    Wouldn't it be better if freeze wrote a freeze-ID to the fs and returned it?
    This would naturally be kept in the image and a UUID mismatch would be
    detectable - seems safer and more flexible than 'a script'.

    "This isn't the freeze you're looking for, move along"

    David
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