This adds assertions that ensure that the necessary write permissions have been granted before someone attempts to write to a node.
Signed-off-by: Kevin Wolf <kw...@redhat.com> --- block/io.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/block/io.c b/block/io.c index cb2feff..74929e5 100644 --- a/block/io.c +++ b/block/io.c @@ -925,9 +925,11 @@ bdrv_driver_pwritev_compressed(BlockDriverState *bs, uint64_t offset, return drv->bdrv_co_pwritev_compressed(bs, offset, bytes, qiov); } -static int coroutine_fn bdrv_co_do_copy_on_readv(BlockDriverState *bs, +static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child, int64_t offset, unsigned int bytes, QEMUIOVector *qiov) { + BlockDriverState *bs = child->bs; + /* Perform I/O through a temporary buffer so that users who scribble over * their read buffer while the operation is in progress do not end up * modifying the image file. This is critical for zero-copy guest I/O @@ -943,6 +945,8 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BlockDriverState *bs, size_t skip_bytes; int ret; + assert(child->perm & (BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE)); + /* Cover entire cluster so no additional backing file I/O is required when * allocating cluster in the image file. */ @@ -1051,7 +1055,7 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child, } if (!ret || pnum != nb_sectors) { - ret = bdrv_co_do_copy_on_readv(bs, offset, bytes, qiov); + ret = bdrv_co_do_copy_on_readv(child, offset, bytes, qiov); goto out; } } @@ -1334,6 +1338,7 @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child, assert(!waited || !req->serialising); assert(req->overlap_offset <= offset); assert(offset + bytes <= req->overlap_offset + req->overlap_bytes); + assert(child->perm & BLK_PERM_WRITE); ret = notifier_with_return_list_notify(&bs->before_write_notifiers, req); -- 1.8.3.1