On 11/2/26 17:30, Eric Blake wrote: > On Fri, Oct 30, 2026 at 12:08:24PM +0100, Denis V. Lunev wrote: >> On 8/12/26 14:14, Denis V. Lunev wrote: >>> 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 > Looks like this one has sat for a while; while it is not directly > related to my usual NBD pulls, I'm in the middle of preparing a block > layer pull request today so I'll add this one in my queue if it passes > my testing. > That would be very kind of you.
This one is circulating here for months. Den
