9p: treat read return values of 0 as EOF

If your 9p server shares a synthetic file system such as sysfs, the file
size from stat often disagrees with the actual file size.

Treat non-error reads of 0 as EOF, except in the case where the request
was for 0 bytes.

Tested:
	git@github.com:hugelgupf/p9.git, served "/" on 10.0.2.2

	bash-5.3# mount -t 9p -o trans=tcp,port=12345,cache=none 10.0.2.2 /tmp/foo
	bash-5.3# cat /tmp/foo/sys/devices/system/cpu/online
	0-47

Fixes: eb497943fa21 ("9p: Convert to using the netfs helper lib to do reads and caching")
Signed-off-by: Barret Rhoden <brho@google.com>
Message-ID: <20260702090941.1298188-1-brho@google.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>

0 files changed, 0 insertions, 0 deletions