Messages in this thread | | | Subject | Re: scary ext2 filesystem question | Date | Sat, 26 Dec 1998 02:27:09 -0400 | From | Horst von Brand <> |
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alan@lxorguk.ukuu.org.uk (Alan Cox) said:
[...]
> Standard BSD writes metadata synchronously. This means it writes the size > and block lists before the data. On a crash and fsck you get files that are > correct to fsck (the block info is right) but whose data was never written.
> On Linux you may also not get the file itself if it was just created. > fsck has to be a little smarter but there is no difference on a data > integrity issue.
Isn't it that Linux may write data before writing metadata, so it could write the data, but it doesn't show up in the (on-disk) file? As a result, FFS might give you a file with garbage (allocated blocks that were never written to), Linux might give you a short file (or loose it completely). Is that correct?
Next question, how long are the respective windows of vulnerability to a crash? To the next sync(2), i.e., on average 15s?
If the above is true, it looks like both are roughly equally vulnerable, but I'd prefer the Linux failure mode. -- Horst von Brand vonbrand@sleipnir.valparaiso.cl Casilla 9G, Viña del Mar, Chile +56 32 672616
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