Merge tag 'block-pull-request' of https://gitlab.com/stefanha/qemu into staging
Pull request
Fix for an fd leak in the blkio block driver.
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# gpg: Signature made Thu 03 Aug 2023 08:55:41 AM PDT
# gpg: using RSA key 8695A8BFD3F97CDAAC35775A9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>" [full]
# gpg: aka "Stefan Hajnoczi <stefanha@gmail.com>" [full]
* tag 'block-pull-request' of https://gitlab.com/stefanha/qemu:
block/blkio: add more comments on the fd passing handling
block/blkio: close the fd when blkio_connect() fails
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
diff --git a/block/blkio.c b/block/blkio.c
index 8e7ce42..1dd4956 100644
--- a/block/blkio.c
+++ b/block/blkio.c
@@ -678,7 +678,7 @@
const char *path = qdict_get_try_str(options, "path");
BDRVBlkioState *s = bs->opaque;
bool fd_supported = false;
- int fd, ret;
+ int fd = -1, ret;
if (!path) {
error_setg(errp, "missing 'path' option");
@@ -713,12 +713,19 @@
*/
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);
if (ret < 0) {
fd_supported = false;
qemu_close(fd);
+ fd = -1;
}
}
}
@@ -733,14 +740,21 @@
}
ret = blkio_connect(s->blkio);
+ if (ret < 0 && fd >= 0) {
+ /* Failed to give the FD to libblkio, close it */
+ qemu_close(fd);
+ fd = -1;
+ }
+
/*
- * 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) {
- qemu_close(fd);
-
/*
* We need to clear the `fd` property we set previously by setting
* it to -1.
