2011/7/26 Kevin Wolf <kw...@redhat.com>: > In order to be able to transparently replace bdrv_read calls by bdrv_co_read, > reading beyond EOF must produce zeros instead of short reads for AIO, too. > > Signed-off-by: Kevin Wolf <kw...@redhat.com> > --- > posix-aio-compat.c | 19 +++++++++++++++++++ > 1 files changed, 19 insertions(+), 0 deletions(-) > > diff --git a/posix-aio-compat.c b/posix-aio-compat.c > index 788d113..8dc00cb 100644 > --- a/posix-aio-compat.c > +++ b/posix-aio-compat.c > @@ -198,6 +198,12 @@ static ssize_t handle_aiocb_rw_vector(struct qemu_paiocb > *aiocb) > return len; > } > > +/* > + * Read/writes the data to/from a given linear buffer. > + * > + * Returns the number of bytes handles or -errno in case of an error. Short > + * reads are only returned if the end of the file is reached. > + */ > static ssize_t handle_aiocb_rw_linear(struct qemu_paiocb *aiocb, char *buf) > { > ssize_t offset = 0; > @@ -334,6 +340,19 @@ static void *aio_thread(void *unused) > > switch (aiocb->aio_type & QEMU_AIO_TYPE_MASK) { > case QEMU_AIO_READ: > + ret = handle_aiocb_rw(aiocb); > + if (ret >= 0 && ret < aiocb->aio_nbytes && > aiocb->common.bs->growable) { > + /* A short read means that we have reached EOF. Pad the > buffer > + * with zeros for bytes after EOF. */ > + QEMUIOVector qiov; > + > + qemu_iovec_init_external(&qiov, aiocb->aio_iov, > + aiocb->aio_niov); > + qemu_iovec_memset_skip(&qiov, 0, aiocb->aio_nbytes - ret, > ret); > + > + ret = aiocb->aio_nbytes; > + } > + break; > case QEMU_AIO_WRITE: > ret = handle_aiocb_rw(aiocb); > break; > -- > 1.7.6 >
Still not tested but I think to know what does it solve :) I think Linux AIO require same attention. Frediano