Re: Strange remount behaviour with ext3-2.4-0.9.4

Chris Wedgwood
2001-07-27T21:08:41Z

On Fri, Jul 27, 2001 at 09:46:57PM +0100, Alan Cox wrote:

2. The software suspend case is horrible. Right now mixing a
journalling fs and swsuspend tends to cause disk corruption because
journalling fs's write to disk when told to mount read only

this is hard to fix... the fs needs to replay things to make things
consistent, and in many cases doing an 'in-memory' replay isn't an
option (ie. remember which stuff needs to replayed and read from the
journal instead of disk when required to do so)

4. Snapshots. Making read only snapshots can be very useful, and there
you want the replay of the log to be into the page cache but not
written back to physical media until its marked read-write

R/O snapshots are best done in the fs if possible, al la
WAFL. Something like that for resierfs or TUX2 would rule so much (you
more-or-less need need a tree-based fs and reference counting for all
the magic bits). In fact, doing it as the fs layer means you could
have r/w snapshots with COW semantics.

--cw