From fa21e6faa6f1d7de49fd030ebdb0722b59cf9a41 Mon Sep 17 00:00:00 2001 From: "Denis V. Lunev" Date: Fri, 6 Feb 2015 14:24:43 +0300 Subject: [PATCH] nbd: fix max_discard/max_transfer_length nbd_co_discard calls nbd_client_session_co_discard which uses uint32_t as the length in bytes of the data to discard due to the following definition: struct nbd_request { uint32_t magic; uint32_t type; uint64_t handle; uint64_t from; uint32_t len; <-- the length of data to be discarded, in bytes } QEMU_PACKED; Thus we should limit bl_max_discard to UINT32_MAX >> BDRV_SECTOR_BITS to avoid overflow. NBD read/write code uses the same structure for transfers. Fix max_transfer_length accordingly. Signed-off-by: Denis V. Lunev CC: Peter Lieven CC: Kevin Wolf Signed-off-by: Kevin Wolf --- block/nbd.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/block/nbd.c b/block/nbd.c index 2e20831715..b05d1d0407 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -301,6 +301,12 @@ static int nbd_co_flush(BlockDriverState *bs) return nbd_client_session_co_flush(&s->client); } +static void nbd_refresh_limits(BlockDriverState *bs, Error **errp) +{ + bs->bl.max_discard = UINT32_MAX >> BDRV_SECTOR_BITS; + bs->bl.max_transfer_length = UINT32_MAX >> BDRV_SECTOR_BITS; +} + static int nbd_co_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors) { @@ -396,6 +402,7 @@ static BlockDriver bdrv_nbd = { .bdrv_close = nbd_close, .bdrv_co_flush_to_os = nbd_co_flush, .bdrv_co_discard = nbd_co_discard, + .bdrv_refresh_limits = nbd_refresh_limits, .bdrv_getlength = nbd_getlength, .bdrv_detach_aio_context = nbd_detach_aio_context, .bdrv_attach_aio_context = nbd_attach_aio_context, @@ -413,6 +420,7 @@ static BlockDriver bdrv_nbd_tcp = { .bdrv_close = nbd_close, .bdrv_co_flush_to_os = nbd_co_flush, .bdrv_co_discard = nbd_co_discard, + .bdrv_refresh_limits = nbd_refresh_limits, .bdrv_getlength = nbd_getlength, .bdrv_detach_aio_context = nbd_detach_aio_context, .bdrv_attach_aio_context = nbd_attach_aio_context, @@ -430,6 +438,7 @@ static BlockDriver bdrv_nbd_unix = { .bdrv_close = nbd_close, .bdrv_co_flush_to_os = nbd_co_flush, .bdrv_co_discard = nbd_co_discard, + .bdrv_refresh_limits = nbd_refresh_limits, .bdrv_getlength = nbd_getlength, .bdrv_detach_aio_context = nbd_detach_aio_context, .bdrv_attach_aio_context = nbd_attach_aio_context,