On 8/12/26 14:14, Denis V. Lunev wrote: > This email originated from an IP that might not be authorized by the domain > it was sent from. > Do not click links or open attachments unless it is an email you expected to > receive. > qom-set of the 'drive' property is allowed on a realized device and ends > up in bdrv_replace_child_bs(), which swaps the node a BdrvChild points to > without telling the parent anything about it. Every other way the size of > a node changes goes through bdrv_co_truncate(), which does notify, so a > device model caching the size of its child has no way to learn that it > changed. > > scsi-disk is the one really hurt by this. check_lba_range() validates > every guest request against SCSIDevice.max_lba, filled in by > scsi_disk_reset() and updated only by the READ CAPACITY(10) and (16) > handlers. Point a scsi-hd at a larger node and every request past the end > of the old one is refused with ILLEGAL REQUEST / LOGICAL BLOCK ADDRESS > OUT OF RANGE for the whole life of the device, which Linux turns into > EREMOTEIO for reads as well as writes. It is silent on the host: > out-of-range requests are answered by scsi_check_condition() and never > reach scsi_handle_rw_error(), so there is no BLOCK_IO_ERROR event and > io-status stays 'ok'. virtio-blk and ide call blk_get_geometry() for > every request, so they end up with a stale idea of the size but never > refuse I/O the node underneath can serve. > > Signed-off-by: Denis V. Lunev <[email protected]> > Cc: Kevin Wolf <[email protected]> > Cc: Hanna Reitz <[email protected]> > Cc: Paolo Bonzini <[email protected]> > Cc: Fam Zheng <[email protected]> > > Denis V. Lunev (4): > block: notify the parent when a replaced child has a different size > scsi-disk: refresh the cached capacity from the resize callback > tests/qtest/virtio-scsi: cover a replacement that changes the size > tests/qemu-iotests/qom-set-drive: replace with a differently sized > node > > block.c | 13 +++++ > hw/scsi/scsi-disk.c | 16 ++++-- > include/block/block_int-io.h | 3 ++ > tests/qemu-iotests/tests/qom-set-drive | 14 +++-- > tests/qemu-iotests/tests/qom-set-drive.out | 2 + > tests/qtest/virtio-scsi-test.c | 63 ++++++++++++++++++++++ > 6 files changed, 104 insertions(+), 7 deletions(-) > > > base-commit: 3e3ccab106f879b1512f8e0d51a827dd4de30e22 ping
