Re: [PATCH] uapi: add EROBLK

On Tue, Nov 19, 2024 at 08:22:08AM -0800, Christoph Hellwig wrote:

On Tue, Nov 19, 2024 at 06:54:52PM +0300, Alexey Dobriyan wrote:

quoted

Block drivers and DM sometimes use EROFS to report errors. There is
no confusion about what happens but naive error reporting code might
pass -EROFS to strerror(3) which will print "filesystem" when clearly
there is no filesystem anywhere, it is layer above.

Or in other words, if EROFS exists, why not EROBLK?
It is not like there is a tax on errno values.

And where would you return this value without breaking existing
userspace?

New code may start returning it right away.

Old code may start checking for both and in ~100 years delete EROFS
clause.