Messages in this thread | ![/](/images/icornerl.gif) | | Date | Thu, 4 Sep 2003 09:12:56 -0700 | From | Andrew Morton <> | Subject | Re: precise characterization of ext3 atomicity |
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Hans Reiser <reiser@namesys.com> wrote: > > Perhaps the following is correct? > > By contrast, ext3 in data=journal and data=ordered modes only guarantees the atomicity of a single write > that does not span a page boundary, and it guarantees that its internal > metadata will not be corrupted even if your application's data is > corrupted after the crash (due to the application spreading what should be committed atomically across more than one block).
Correct != comprehensible ;)
"In all journalling modes ext3 guarantees metadata consistency after a crash. In its data=journal and data=ordered modes ext3 also guarantees that user data is consistent with metadata after a crash.
However ext3 does not provide user data atomicity guarantees beyond the scope of a single filesystem disk block (usually 4 kilobytes). If a single write() spans two disk blocks it is possible that a crash partway through the write will result in only one of those blocks appearing in the file after recovery"
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