On Sun, Aug 29, 2021 at 03:12:16PM -0700, Jon Steinhart wrote:
> After a bit of poking around I discovered that btrfs SILENTLY remounted the
> filesystem because it had errors.  Sure, it put something in a log file,
> but I don't spend all day surfing logs for things that shouldn't be going
> wrong.  Maybe my expectation that filesystems just work is antiquated.

I give them credit for remounting read-only when seeing errors, they may
have gotten that from BitKeeper.  When we opened a history file, if we
encountered any errors we opened the history file in read only mode so
if it worked enough you could see your data, great, but don't write on
top of bad data.

> Although it's been discredited by some, I'm still a believer in "stop and
> fsck" policing of disk drives. 

Me too.  Though with a 32TB drive (I'm guessing rotating media), that's
going to take a long time.   If I had a drive that big, I'd divide it
into managable chunks and mount them all under /drive/{a,b,c,d,e...}
so that when something goes wrong you don't have to check the whole
32TB.

> Near the top of the manual page it says:
>
>   Warning
>     Do not use --repair unless you are advised to do so by a developer
>     or an experienced user, and then only after having accepted that
>     no fsck successfully repair all types of filesystem corruption. Eg.
>     some other software or hardware bugs can fatally damage a volume.
>
> Whoa!  I'm sure that operators are standing by, call 1-800-FIX-BTRFS.
> Really?  Is a ploy by the developers to form a support business?

That's a stretch, they are just trying to not encourage you to make a
mess.

I sent Linus an email to find out where btrfs is, I'll report back when
he replies.

--lm