RBD APIs don't allow us to write more than the size set with rbd_create() or rbd_resize(). In order to support growing images (eg. qcow2), we resize the image before RW operations that exceed the current size.
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1171007 Signed-off-by: Stefano Garzarella <sgarz...@redhat.com> --- block/rbd.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/block/rbd.c b/block/rbd.c index 0c549c9935..228658e20a 100644 --- a/block/rbd.c +++ b/block/rbd.c @@ -102,6 +102,7 @@ typedef struct BDRVRBDState { rbd_image_t image; char *image_name; char *snap; + uint64_t image_size; } BDRVRBDState; static int qemu_rbd_connect(rados_t *cluster, rados_ioctx_t *io_ctx, @@ -777,6 +778,14 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags, goto failed_open; } + r = rbd_get_size(s->image, &s->image_size); + if (r < 0) { + error_setg_errno(errp, -r, "error reading image size from %s", + s->image_name); + rbd_close(s->image); + goto failed_open; + } + /* If we are using an rbd snapshot, we must be r/o, otherwise * leave as-is */ if (s->snap != NULL) { @@ -921,6 +930,20 @@ static BlockAIOCB *rbd_start_aio(BlockDriverState *bs, rcb->buf = acb->bounce; } + /* + * RBD APIs don't allow us to write more than actual size, so in order + * to support growing images, we resize the image before RW operations + * that exceed the current size. + */ + if (s->image_size < off + size) { + r = rbd_resize(s->image, off + size); + if (r < 0) { + goto failed; + } + + s->image_size = off + size; + } + acb->ret = 0; acb->error = 0; acb->s = s; @@ -1066,6 +1089,8 @@ static int coroutine_fn qemu_rbd_co_truncate(BlockDriverState *bs, return r; } + s->image_size = offset; + return 0; } -- 2.20.1
