Re: Advice about ext3, please (An experiment & results)
> The message doesn't -tell- you what to do, but what I think one should
> do is plug in the USB drive again and do fsck on the device. When fsck
> runs, in immediately reruns the journal and fixes metadata
Mounting the device would have done the same thing (even if mounted
read-only, actually: you'd get a message along the lines of "enabling
read-write while replaying the journal"). So running fsck is really not
needed in this case.
> What it may not do is actually write data that was waiting in some
> buffer. (fsck has a option to force a full check even if the fast,
> incomplete check using the journal indicates that things are
> fixed. I did this, and fsck found no detailed errors either.)
Indeed, fsck can still be useful if you want to force a full check
(which mount won't do).
> The computer did have to be re-booted before the fsck.
AFAIK this depends on many things. In my experience, the system is
still perfectly usable afterwards, except that it still has some
"pending operations" for that now-non-existent device, so you may be
unable to unmount the drive and re-inserting the USB drive will usually
give it some new device name (because the old one is still in use).
So it has never been enough to force me to reboot, but if you do it
often you will eventually need to reboot.
So, yes, unplugging your USB key while it's still mounted is to be
avoided, and even more so while it's being written to.