Messages in this thread | | | Date | Tue, 2 Dec 2008 20:10:42 +0100 | From | Folkert van Heusden <> | Subject | Re: writing file to disk: not as easy as it looks |
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> > If disk looses data after acknowledging the write, all hope is lost. > > Else I expect filesystem to preserve data I successfully synced. > > (In the b-tree split failed case I'd expect transaction commit to > > fail because new data could not be weitten; at that point > > disk+journal should still contain all the data needed for > > recovery of synced/old files, right?) > > Not necessarily. For filesystems that do logical journalling (i.e., > xfs, jfs, et. al), the only thing written in the journal is the > logical change (i.e., "new dir entry 'file_that_causes_the_node_split'").
> The transaction commits *first*, and then the filesystem tries to > write update the filesystem with the change, and it's only then that > the write fails. Data can very easily get lost.
> Even for ext3/ext4 which is doing physical journalling, it's still the
So do I understand this right that ext3/4 are more robust?
Folkert van Heusden
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