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Re: not mounting ext3, 2.4.10



Hi,

On Tue, Sep 25, 2001 at 04:55:07PM -0700, Mike Fedyk wrote:

> Is it true now that you can't modify the block device once it is mounted now
> that the buffer cache is in the page cache?

The buffer cache is still separate from the page cache.  What changed
is that block device IO from user space is now done through the page
cache (filesystems can still go via the buffer cache).

The impact is that user-space IO to a mounted block device is unsafe,
not that it is impossible.  If the filesystem has a block cached in
the buffer cache and the user modifies it in the page cache, then
neither will see the change done by the other, and they can overwrite
each others' updates.

Cheers,
 Stephen





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