True, thanks for pointing that out; the simplest way to solve this for
my purposes is to snapshot those superblock fields and restore them
That's an interesting approach, although as you point out it only
works on file systems with a 4k block size. Your design seems to be
focused on recording only the most recent logs, which makes sense in a
debugging environment. My assumption was that the most recent
problems would probably be recorded in /var/log/messages, although if
the problem occurred on a single-disk system, that assumption probably
wouldn't hold true. I wonder if the a better solution for this
particular use case is much larger ring buffer, and a hook into the
printk system which is guaranteed to record *everything*, even after a
panic or after the journal has been aborted and the file system has
been remounted read-only.
For the patch I wrote, my intention was as a supplement to
/var/log/messages --- where s_first_error_time might be from long
after /var/log/messages had rolled over. So I was trying to solve a
somewhat different problem. (Hmm, actually, it would probably be good
to save both details about the first as well as the most recent error.)
- Ted
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