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| author | Stefano Garzarella <sgarzare@redhat.com> | 2023-08-03 10:28:25 +0200 |
|---|---|---|
| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2023-08-03 11:28:43 -0400 |
| commit | 9b06d0d076271d76e5384d767ef94a676f0a9efd (patch) | |
| tree | bb288f9a924193fee5802caa2bc882c1226eaed4 /block | |
| parent | 0b054b4c82ebad6e90111e3ffa3514f841dbb1d0 (diff) | |
| download | qemu-9b06d0d076271d76e5384d767ef94a676f0a9efd.zip qemu-9b06d0d076271d76e5384d767ef94a676f0a9efd.tar.gz qemu-9b06d0d076271d76e5384d767ef94a676f0a9efd.tar.bz2 | |
block/blkio: add more comments on the fd passing handling
As Hanna pointed out, it is not clear in the code why qemu_open()
can fail, and why blkio_set_int("fd") is not enough to discover
the `fd` property support.
Let's fix them by adding more details in the code comments.
Suggested-by: Hanna Czenczek <hreitz@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-id: 20230803082825.25293-3-sgarzare@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blkio.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/block/blkio.c b/block/blkio.c index baba2f0..1dd4956 100644 --- a/block/blkio.c +++ b/block/blkio.c @@ -713,6 +713,12 @@ static int blkio_virtio_blk_connect(BlockDriverState *bs, QDict *options, */ fd = qemu_open(path, O_RDWR, NULL); if (fd < 0) { + /* + * qemu_open() can fail if the user specifies a path that is not + * a file or device, for example in the case of Unix Domain Socket + * for the virtio-blk-vhost-user driver. In such cases let's have + * libblkio open the path directly. + */ fd_supported = false; } else { ret = blkio_set_int(s->blkio, "fd", fd); @@ -741,9 +747,12 @@ static int blkio_virtio_blk_connect(BlockDriverState *bs, QDict *options, } /* - * If the libblkio driver doesn't support the `fd` property, blkio_connect() - * will fail with -EINVAL. So let's try calling blkio_connect() again by - * directly setting `path`. + * Before https://gitlab.com/libblkio/libblkio/-/merge_requests/208 + * (libblkio <= v1.3.0), setting the `fd` property is not enough to check + * whether the driver supports the `fd` property or not. In that case, + * blkio_connect() will fail with -EINVAL. + * So let's try calling blkio_connect() again by directly setting `path` + * to cover this scenario. */ if (fd_supported && ret == -EINVAL) { /* |