Messages in this thread | | | Date | Sun, 4 Jan 2009 14:36:37 -0500 | From | Theodore Tso <> | Subject | Re: document ext3 requirements |
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On Sun, Jan 04, 2009 at 08:21:06PM +0100, Geert Uytterhoeven wrote: > As mentioned before, suspending a laptop (running from hdd), running > a live CD, and expecting everything to work fine when resuming from > hdd? > > I think most people get shocked when they discover that mounting > something read-only may actualy write to the media. This is a bit > unexpected (hey, if I mount `read-only', I expect that no writes > will happen), as it behaved differently before the introduction of > journalling.
It's been this way for about a decade.... that being said, if you really want to do this, you can today via "mount -o ro,noload /dev/XXX /mntpt". However, the system could crash or fail because the filesystem without having run the journal could be quite inconsistent.
> As for mounting the root file system read-only during early boot up, and > remounting it read-write later, I guess it's quite complicated to replay the > journal (in RAM) on read-only mount, and deferring the replay writeback until > remounting read-write?
It's not *that* hard; if someone would like to cons up a patch, please feel free.... but it's certainly not a high priority for me or most of the other ext3 filesystem developers.
- Ted
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