On 10/10/17 21:09, Jes Sorensen wrote:

quoted

Both operations would share the current code, just apply a different
sanity check before proceeding.

"grow" in mdadmlish translates to reshape/resize in English. Starting to
introduce new keywords for this really makes no sense and just cause
confusion, so I am not going to support that.

But saying "grow" when the result is a shrink also causes confusion.
Would you accept changing "grow" to "resize"?

But personally I think adding a new keyword is sensible. Firstly, in
normal use no-one is ever going to want to shrink an array, so this is
rarely going to be used.

And secondly, if you use "grow" to grow an array, it's a "safe"
operation (unless something goes wrong). If you use "grow" to *shrink*
an array, as Eli found out, it's very dangerous.

I think abusing the English language is far more dangerous than adding a
new keyword. No disrespect to them, but you forget your average sysadmin
is, well, average. Handing them a loaded foot-gun with no safety-catch
is *not* a good idea. (And even a good sysadmin will spend little time
with mdadm. Even if they know this now, there's a good chance they'll
forget before they need it again, and it becomes a land-mine waiting to
go off ...)

One only has to look at the "hung grow" thread to see what the lack of
safety-catches can do - if anybody wants another little project, might
it be an idea to make a load of operations (like resize for example)
block on a degraded array?

Cheers,
Wol