qemu-iotests: add read/write from smaller backing image test

Some image formats support backing images that are smaller than the
image file.  This patch adds a test that verifies that reads and writes
beyond the end of backing image work.

Unallocated reads beyond the end of the backing file should produce
zeroes.

Writes beyond the end of the backing file should copy-on-write using
zeroes.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Stefan Hajnoczi 2010-10-15 07:56:35 -07:00 committed by Kevin Wolf
parent 89d22bc306
commit 8268b7675c
3 changed files with 560 additions and 0 deletions

View file

@ -34,3 +34,4 @@
025 rw auto
026 rw blkdbg auto
027 rw auto
028 rw backing auto