* THE SOFTWARE.
*/
#include "config-host.h"
-#ifdef HOST_BSD
-/* include native header before sys-queue.h */
-#include <sys/queue.h>
-#endif
-
#include "qemu-common.h"
#include "monitor.h"
#include "block_int.h"
#include "module.h"
-#ifdef HOST_BSD
+#ifdef CONFIG_BSD
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
+#include <sys/queue.h>
#ifndef __DragonFly__
#include <sys/disk.h>
#endif
static BlockDriverAIOCB *bdrv_aio_writev_em(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque);
+static BlockDriverAIOCB *bdrv_aio_flush_em(BlockDriverState *bs,
+ BlockDriverCompletionFunc *cb, void *opaque);
static int bdrv_read_em(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors);
static int bdrv_write_em(BlockDriverState *bs, int64_t sector_num,
bdrv->bdrv_read = bdrv_read_em;
bdrv->bdrv_write = bdrv_write_em;
}
+
+ if (!bdrv->bdrv_aio_flush)
+ bdrv->bdrv_aio_flush = bdrv_aio_flush_em;
+
bdrv->next = first_drv;
first_drv = bdrv;
}
}
bs->drv = drv;
bs->opaque = qemu_mallocz(drv->instance_size);
+
+ /*
+ * Yes, BDRV_O_NOCACHE aka O_DIRECT means we have to present a
+ * write cache to the guest. We do need the fdatasync to flush
+ * out transactions for block allocations, and we maybe have a
+ * volatile write cache in our backing device to deal with.
+ */
+ if (flags & (BDRV_O_CACHE_WB|BDRV_O_NOCACHE))
+ bs->enable_write_cache = 1;
+
/* Note: for compatibility, we open disk image files as RDWR, and
RDONLY as fallback */
if (!(flags & BDRV_O_FILE))
- open_flags = BDRV_O_RDWR | (flags & BDRV_O_CACHE_MASK);
+ open_flags = BDRV_O_RDWR |
+ (flags & (BDRV_O_CACHE_MASK|BDRV_O_NATIVE_AIO));
else
open_flags = flags & ~(BDRV_O_FILE | BDRV_O_SNAPSHOT);
ret = drv->bdrv_open(bs, filename, open_flags);
return bs->sg;
}
+int bdrv_enable_write_cache(BlockDriverState *bs)
+{
+ return bs->enable_write_cache;
+}
+
/* XXX: no longer used */
void bdrv_set_change_cb(BlockDriverState *bs,
void (*change_cb)(void *opaque), void *opaque)
return ret;
}
+
+typedef struct MultiwriteCB {
+ int error;
+ int num_requests;
+ int num_callbacks;
+ struct {
+ BlockDriverCompletionFunc *cb;
+ void *opaque;
+ QEMUIOVector *free_qiov;
+ void *free_buf;
+ } callbacks[];
+} MultiwriteCB;
+
+static void multiwrite_user_cb(MultiwriteCB *mcb)
+{
+ int i;
+
+ for (i = 0; i < mcb->num_callbacks; i++) {
+ mcb->callbacks[i].cb(mcb->callbacks[i].opaque, mcb->error);
+ qemu_free(mcb->callbacks[i].free_qiov);
+ qemu_free(mcb->callbacks[i].free_buf);
+ }
+}
+
+static void multiwrite_cb(void *opaque, int ret)
+{
+ MultiwriteCB *mcb = opaque;
+
+ if (ret < 0) {
+ mcb->error = ret;
+ multiwrite_user_cb(mcb);
+ }
+
+ mcb->num_requests--;
+ if (mcb->num_requests == 0) {
+ if (mcb->error == 0) {
+ multiwrite_user_cb(mcb);
+ }
+ qemu_free(mcb);
+ }
+}
+
+static int multiwrite_req_compare(const void *a, const void *b)
+{
+ return (((BlockRequest*) a)->sector - ((BlockRequest*) b)->sector);
+}
+
+/*
+ * Takes a bunch of requests and tries to merge them. Returns the number of
+ * requests that remain after merging.
+ */
+static int multiwrite_merge(BlockDriverState *bs, BlockRequest *reqs,
+ int num_reqs, MultiwriteCB *mcb)
+{
+ int i, outidx;
+
+ // Sort requests by start sector
+ qsort(reqs, num_reqs, sizeof(*reqs), &multiwrite_req_compare);
+
+ // Check if adjacent requests touch the same clusters. If so, combine them,
+ // filling up gaps with zero sectors.
+ outidx = 0;
+ for (i = 1; i < num_reqs; i++) {
+ int merge = 0;
+ int64_t oldreq_last = reqs[outidx].sector + reqs[outidx].nb_sectors;
+
+ // This handles the cases that are valid for all block drivers, namely
+ // exactly sequential writes and overlapping writes.
+ if (reqs[i].sector <= oldreq_last) {
+ merge = 1;
+ }
+
+ // The block driver may decide that it makes sense to combine requests
+ // even if there is a gap of some sectors between them. In this case,
+ // the gap is filled with zeros (therefore only applicable for yet
+ // unused space in format like qcow2).
+ if (!merge && bs->drv->bdrv_merge_requests) {
+ merge = bs->drv->bdrv_merge_requests(bs, &reqs[outidx], &reqs[i]);
+ }
+
+ if (merge) {
+ size_t size;
+ QEMUIOVector *qiov = qemu_mallocz(sizeof(*qiov));
+ qemu_iovec_init(qiov,
+ reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1);
+
+ // Add the first request to the merged one. If the requests are
+ // overlapping, drop the last sectors of the first request.
+ size = (reqs[i].sector - reqs[outidx].sector) << 9;
+ qemu_iovec_concat(qiov, reqs[outidx].qiov, size);
+
+ // We might need to add some zeros between the two requests
+ if (reqs[i].sector > oldreq_last) {
+ size_t zero_bytes = (reqs[i].sector - oldreq_last) << 9;
+ uint8_t *buf = qemu_blockalign(bs, zero_bytes);
+ memset(buf, 0, zero_bytes);
+ qemu_iovec_add(qiov, buf, zero_bytes);
+ mcb->callbacks[i].free_buf = buf;
+ }
+
+ // Add the second request
+ qemu_iovec_concat(qiov, reqs[i].qiov, reqs[i].qiov->size);
+
+ reqs[outidx].nb_sectors += reqs[i].nb_sectors;
+ reqs[outidx].qiov = qiov;
+
+ mcb->callbacks[i].free_qiov = reqs[outidx].qiov;
+ } else {
+ outidx++;
+ reqs[outidx].sector = reqs[i].sector;
+ reqs[outidx].nb_sectors = reqs[i].nb_sectors;
+ reqs[outidx].qiov = reqs[i].qiov;
+ }
+ }
+
+ return outidx + 1;
+}
+
+/*
+ * Submit multiple AIO write requests at once.
+ *
+ * On success, the function returns 0 and all requests in the reqs array have
+ * been submitted. In error case this function returns -1, and any of the
+ * requests may or may not be submitted yet. In particular, this means that the
+ * callback will be called for some of the requests, for others it won't. The
+ * caller must check the error field of the BlockRequest to wait for the right
+ * callbacks (if error != 0, no callback will be called).
+ *
+ * The implementation may modify the contents of the reqs array, e.g. to merge
+ * requests. However, the fields opaque and error are left unmodified as they
+ * are used to signal failure for a single request to the caller.
+ */
+int bdrv_aio_multiwrite(BlockDriverState *bs, BlockRequest *reqs, int num_reqs)
+{
+ BlockDriverAIOCB *acb;
+ MultiwriteCB *mcb;
+ int i;
+
+ if (num_reqs == 0) {
+ return 0;
+ }
+
+ // Create MultiwriteCB structure
+ mcb = qemu_mallocz(sizeof(*mcb) + num_reqs * sizeof(*mcb->callbacks));
+ mcb->num_requests = 0;
+ mcb->num_callbacks = num_reqs;
+
+ for (i = 0; i < num_reqs; i++) {
+ mcb->callbacks[i].cb = reqs[i].cb;
+ mcb->callbacks[i].opaque = reqs[i].opaque;
+ }
+
+ // Check for mergable requests
+ num_reqs = multiwrite_merge(bs, reqs, num_reqs, mcb);
+
+ // Run the aio requests
+ for (i = 0; i < num_reqs; i++) {
+ acb = bdrv_aio_writev(bs, reqs[i].sector, reqs[i].qiov,
+ reqs[i].nb_sectors, multiwrite_cb, mcb);
+
+ if (acb == NULL) {
+ // We can only fail the whole thing if no request has been
+ // submitted yet. Otherwise we'll wait for the submitted AIOs to
+ // complete and report the error in the callback.
+ if (mcb->num_requests == 0) {
+ reqs[i].error = EIO;
+ goto fail;
+ } else {
+ mcb->error = EIO;
+ break;
+ }
+ } else {
+ mcb->num_requests++;
+ }
+ }
+
+ return 0;
+
+fail:
+ free(mcb);
+ return -1;
+}
+
+BlockDriverAIOCB *bdrv_aio_flush(BlockDriverState *bs,
+ BlockDriverCompletionFunc *cb, void *opaque)
+{
+ BlockDriver *drv = bs->drv;
+
+ if (!drv)
+ return NULL;
+
+ /*
+ * Note that unlike bdrv_flush the driver is reponsible for flushing a
+ * backing image if it exists.
+ */
+ return drv->bdrv_aio_flush(bs, cb, opaque);
+}
+
void bdrv_aio_cancel(BlockDriverAIOCB *acb)
{
acb->pool->cancel(acb);
return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
}
+static BlockDriverAIOCB *bdrv_aio_flush_em(BlockDriverState *bs,
+ BlockDriverCompletionFunc *cb, void *opaque)
+{
+ BlockDriverAIOCBSync *acb;
+
+ acb = qemu_aio_get(&bdrv_em_aio_pool, bs, cb, opaque);
+ acb->is_write = 1; /* don't bounce in the completion hadler */
+ acb->qiov = NULL;
+ acb->bounce = NULL;
+ acb->ret = 0;
+
+ if (!acb->bh)
+ acb->bh = qemu_bh_new(bdrv_aio_bh_cb, acb);
+
+ bdrv_flush(bs);
+ qemu_bh_schedule(acb->bh);
+ return &acb->common;
+}
+
/**************************************************************/
/* sync block device emulation */
projects / qemu / blobdiff