Determining ->last_piece based on the value of ->page_offset + length
is incorrect because length here is the length of the entire message.
->last_piece set to false even if page array data item length is <=
PAGE_SIZE, which results in invalid length passed to
ceph_tcp_{send,recv}page() and causes various asserts to fire.
# cat pages-cursor-init.sh
#!/bin/bash
rbd create --size 10 --image-format 2 foo
FOO_DEV=$(rbd map foo)
dd if=/dev/urandom of=$FOO_DEV bs=1M &>/dev/null
rbd snap create foo@snap
rbd snap protect foo@snap
rbd clone foo@snap bar
# rbd_resize calls librbd rbd_resize(), size is in bytes
./rbd_resize bar $(((4 << 20) + 512))
rbd resize --size 10 bar
BAR_DEV=$(rbd map bar)
# trigger a 512-byte copyup -- 512-byte page array data item
dd if=/dev/urandom of=$BAR_DEV bs=1M count=1 seek=5
The problem exists only in ceph_msg_data_pages_cursor_init(),
ceph_msg_data_pages_advance() does the right thing. The size_t cast is
unnecessary.
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Sage Weil <sage@redhat.com>
Reviewed-by: Alex Elder <elder@linaro.org>
5f740d7e15