Re: [PATCH blktests] bcache: add bcache/001

[Christoph Hellwig <hch@infradead.org>]

On Wed, Jan 21, 2026 at 01:48:27PM +0100, Daniel Wagner wrote:
> Sure, I'll update the documentation.
> 
> On this note, It took me a while to understand that using
> TEST_DEVS="/dev/nvme0n1 /dev/vdb /dev/vdc" is not populating the
> TEST_DEV_ARRAY array.
> 
> Commit 653ace845911 ("check, new: introduce test_device_array()")
> explains why:
> 
>     As to the test target devices defined in TEST_DEVS variable, blktests
>     assumes that each test case with test_device() function is run for each
>     single device defined in TEST_DEVS. On the other hand, it is suggested
>     to support a test case for not a single device but multiple devices.
> 
> Maybe we could add a default config with all options listed and
> documented but commented out.

The default config would be useful for sure.

But I also thing the TEST_DEVS vs TEST_DEV_ARRAY thing is weird, and the
fact that you need to declare the array for multiple tests doesn't help.

IMHO having a TEST_DEV_ARRAY should imply that normal single device tests
pick the first one from it if not explicit TEST_DEVS is set, and tests
using multiple devices can grab as many as they support from it.  That
would mirror what SCRATCH_DEV_POOL does in xfstests, which works very
well.

I'd love to help with this, but I'm not sure my bash abilities are
enough for this :(