On Wed, 22 Jul 2015 15:23:42 -0700 Mike Kravetz [off-list ref] wrote:

On 07/22/2015 03:03 PM, Andrew Morton wrote:

quoted

On Tue, 21 Jul 2015 11:09:43 -0700 Mike Kravetz [off-list ref] wrote:

...

quoted

quoted

+
+	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
+		return -EOPNOTSUPP;

EOPNOTSUPP is a networking thing.  It's inappropriate here.

The problem is that if this error is ever returned to userspace, the
user will be sitting looking at "Operation not supported on transport
endpoint" and wondering what went wrong in the networking stack.

Trying to follow FALLOCATE(2) man page:

"EOPNOTSUPP
	The filesystem containing the file referred to by  fd  does  not
	support  this  operation;  or  the  mode is not supported by the
	filesystem containing the file referred to by fd."

Sigh.