block/qapi: Move 'aio' option to file driver

The option whether or not to use a native AIO interface really isn't a
generic option for all drivers, but only applies to the native file
protocols. This patch moves the option in blockdev-add to the
appropriate places (raw-posix and raw-win32).

We still have to keep the flag BDRV_O_NATIVE_AIO for compatibility
because so far the AIO option was usually specified on the wrong layer
(the top-level format driver, which didn't even look at it) and then
inherited by the protocol driver (where it was actually used). We can't
forbid this use except in new interfaces.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>

1 files changed, 51 insertions, 5 deletions

diff --git a/block/raw-win32.c b/block/raw-win32.c
index 56f45fea9e..734bb105bd 100644
--- a/block/raw-win32.c
+++ b/block/raw-win32.c
@@ -32,6 +32,7 @@
 #include "block/thread-pool.h"
 #include "qemu/iov.h"
 #include "qapi/qmp/qstring.h"
+#include "qapi/util.h"
 #include <windows.h>
 #include <winioctl.h>
 
@@ -252,7 +253,8 @@ static void raw_probe_alignment(BlockDriverState *bs, Error **errp)
     }
 }
 
-static void raw_parse_flags(int flags, int *access_flags, DWORD *overlapped)
+static void raw_parse_flags(int flags, bool use_aio, int *access_flags,
+                            DWORD *overlapped)
 {
     assert(access_flags != NULL);
     assert(overlapped != NULL);
@@ -264,7 +266,7 @@ static void raw_parse_flags(int flags, int *access_flags, DWORD *overlapped)
     }
 
     *overlapped = FILE_ATTRIBUTE_NORMAL;
-    if (flags & BDRV_O_NATIVE_AIO) {
+    if (use_aio) {
         *overlapped |= FILE_FLAG_OVERLAPPED;
     }
     if (flags & BDRV_O_NOCACHE) {
@@ -292,10 +294,35 @@ static QemuOptsList raw_runtime_opts = {
             .type = QEMU_OPT_STRING,
             .help = "File name of the image",
         },
+        {
+            .name = "aio",
+            .type = QEMU_OPT_STRING,
+            .help = "host AIO implementation (threads, native)",
+        },
         { /* end of list */ }
     },
 };
 
+static bool get_aio_option(QemuOpts *opts, int flags, Error **errp)
+{
+    BlockdevAioOptions aio, aio_default;
+
+    aio_default = (flags & BDRV_O_NATIVE_AIO) ? BLOCKDEV_AIO_OPTIONS_NATIVE
+                                              : BLOCKDEV_AIO_OPTIONS_THREADS;
+    aio = qapi_enum_parse(BlockdevAioOptions_lookup, qemu_opt_get(opts, "aio"),
+                          BLOCKDEV_AIO_OPTIONS__MAX, aio_default, errp);
+
+    switch (aio) {
+    case BLOCKDEV_AIO_OPTIONS_NATIVE:
+        return true;
+    case BLOCKDEV_AIO_OPTIONS_THREADS:
+        return false;
+    default:
+        error_setg(errp, "Invalid AIO option");
+    }
+    return false;
+}
+
 static int raw_open(BlockDriverState *bs, QDict *options, int flags,
                     Error **errp)
 {
@@ -305,6 +332,7 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags,
     QemuOpts *opts;
     Error *local_err = NULL;
     const char *filename;
+    bool use_aio;
     int ret;
 
     s->type = FTYPE_FILE;
@@ -319,7 +347,14 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags,
 
     filename = qemu_opt_get(opts, "filename");
 
-    raw_parse_flags(flags, &access_flags, &overlapped);
+    use_aio = get_aio_option(opts, flags, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        ret = -EINVAL;
+        goto fail;
+    }
+
+    raw_parse_flags(flags, use_aio, &access_flags, &overlapped);
 
     if (filename[0] && filename[1] == ':') {
         snprintf(s->drive_path, sizeof(s->drive_path), "%c:\\", filename[0]);
@@ -346,7 +381,7 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags,
         goto fail;
     }
 
-    if (flags & BDRV_O_NATIVE_AIO) {
+    if (use_aio) {
         s->aio = win32_aio_init();
         if (s->aio == NULL) {
             CloseHandle(s->hfile);
@@ -647,6 +682,7 @@ static int hdev_open(BlockDriverState *bs, QDict *options, int flags,
 
     Error *local_err = NULL;
     const char *filename;
+    bool use_aio;
 
     QemuOpts *opts = qemu_opts_create(&raw_runtime_opts, NULL, 0,
                                       &error_abort);
@@ -659,6 +695,16 @@ static int hdev_open(BlockDriverState *bs, QDict *options, int flags,
 
     filename = qemu_opt_get(opts, "filename");
 
+    use_aio = get_aio_option(opts, flags, &local_err);
+    if (!local_err && use_aio) {
+        error_setg(&local_err, "AIO is not supported on Windows host devices");
+    }
+    if (local_err) {
+        error_propagate(errp, local_err);
+        ret = -EINVAL;
+        goto done;
+    }
+
     if (strstart(filename, "/dev/cdrom", NULL)) {
         if (find_cdrom(device_name, sizeof(device_name)) < 0) {
             error_setg(errp, "Could not open CD-ROM drive");
@@ -677,7 +723,7 @@ static int hdev_open(BlockDriverState *bs, QDict *options, int flags,
     }
     s->type = find_device_type(bs, filename);
 
-    raw_parse_flags(flags, &access_flags, &overlapped);
+    raw_parse_flags(flags, use_aio, &access_flags, &overlapped);
 
     create_flags = OPEN_EXISTING;