Re: 2.6.36 io bring the system to its knees

[Christoph Hellwig]

On Wed, Nov 10, 2010 at 03:27:21PM +0100, Ingo Molnar wrote:
> That is data that was freshly touched around the time the system went down, right?
> 
> I.e. data that was probably half-modified by user-space to begin with.

It's data that wasn't synced out yet, yes.  Which isn't the problem per
se.  With ext3/4 in ordered mode, or xfs, or btrfs the file size won't
be incremented until the data is written.  in ext3/4 in writeback mode
(or various non-journaling filesystems) however the inode size is
updated, and metadagta changes are logged.  Besides exposing stale
data which is a security risk in multi-user systems it also means the
inode looks modified (by size and timestamps), but contains other data
than actually written.

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