This implements an asynchronous version of bdrv_pwrite.
Signed-off-by: Kevin Wolf <kw...@redhat.com>
---
block.c | 167 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
block.h | 2 +
2 files changed, 169 insertions(+), 0 deletions(-)
diff --git a/block.c b/block.c
index 63effd8..f10066e 100644
--- a/block.c
+++ b/block.c
@@ -2106,6 +2106,173 @@ BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs,
int64_t sector_num,
return ret;
}
+typedef struct PwriteAIOCB {
+ BlockDriverAIOCB common;
+ int state;
+ int64_t offset;
+ size_t bytes;
+ uint8_t* buf;
+ uint8_t* tmp_buf;
+ struct iovec iov;
+ QEMUIOVector qiov;
+} PwriteAIOCB;
+
+static void pwrite_aio_cancel(BlockDriverAIOCB *blockacb)
+{
+ qemu_aio_flush();
+}
+
+static AIOPool blkqueue_aio_pool = {
+ .aiocb_size = sizeof(PwriteAIOCB),
+ .cancel = pwrite_aio_cancel,
+};
+
+static void bdrv_aio_pwrite_cb(void *opaque, int ret)
+{
+ PwriteAIOCB *acb = opaque;
+ BlockDriverAIOCB *tmp_acb;
+ int64_t sector_num;
+
+ if (ret < 0) {
+ goto done;
+ }
+
+ sector_num = acb->offset >> BDRV_SECTOR_BITS;
+
+ switch (acb->state) {
+ case 0: {
+ /* Read first sector if needed */
+ int len;
+
+ len = (BDRV_SECTOR_SIZE - acb->offset) & (BDRV_SECTOR_SIZE - 1);
+
+ if (len > 0) {
+ acb->state = 1;
+ acb->tmp_buf = qemu_blockalign(acb->common.bs, BDRV_SECTOR_SIZE);
+ acb->iov.iov_base = acb->tmp_buf;
+ acb->iov.iov_len = BDRV_SECTOR_SIZE;
+ qemu_iovec_init_external(&acb->qiov, &acb->iov, 1);
+ tmp_acb = bdrv_aio_readv(acb->common.bs, sector_num, &acb->qiov, 1,
+ bdrv_aio_pwrite_cb, acb);
+ if (tmp_acb == NULL) {
+ bdrv_aio_pwrite_cb(acb, -EIO);
+ }
+ } else {
+ acb->state = 2;
+ bdrv_aio_pwrite_cb(acb, 0);
+ }
+ break;
+ }
+
+ case 1: {
+ /* Modify first cluster and write it back */
+ int len;
+
+ len = (BDRV_SECTOR_SIZE - acb->offset) & (BDRV_SECTOR_SIZE - 1);
+ if (len > acb->bytes) {
+ len = acb->bytes;
+ }
+
+ memcpy(acb->tmp_buf + (acb->offset & (BDRV_SECTOR_SIZE - 1)),
+ acb->buf, len);
+
+ acb->state = 2;
+ acb->offset += len;
+ acb->buf += len;
+ acb->bytes -= len;
+
+ tmp_acb = bdrv_aio_writev(acb->common.bs, sector_num, &acb->qiov, 1,
+ bdrv_aio_pwrite_cb, acb);
+ if (tmp_acb == NULL) {
+ bdrv_aio_pwrite_cb(acb, -EIO);
+ }
+ break;
+ }
+
+ case 2: {
+ /* Write the sectors "in place" */
+ int nb_sectors = acb->bytes >> BDRV_SECTOR_BITS;
+
+ acb->state = 3;
+ if (nb_sectors > 0) {
+ int len = nb_sectors << BDRV_SECTOR_BITS;
+
+ acb->iov.iov_base = acb->buf;
+ acb->iov.iov_len = len;
+ qemu_iovec_init_external(&acb->qiov, &acb->iov, 1);
+
+ acb->offset += len;
+ acb->buf += len;
+ acb->bytes -= len;
+
+ tmp_acb = bdrv_aio_writev(acb->common.bs, sector_num, &acb->qiov,
+ nb_sectors, bdrv_aio_pwrite_cb, acb);
+ if (tmp_acb == NULL) {
+ bdrv_aio_pwrite_cb(acb, -EIO);
+ }
+ } else {
+ bdrv_aio_pwrite_cb(acb, 0);
+ }
+ break;
+ }
+
+ case 3: {
+ /* Read last sector if needed */
+ if (acb->bytes == 0) {
+ goto done;
+ }
+
+ acb->state = 4;
+ acb->iov.iov_base = acb->tmp_buf;
+ acb->iov.iov_len = BDRV_SECTOR_SIZE;
+ qemu_iovec_init_external(&acb->qiov, &acb->iov, 1);
+ tmp_acb = bdrv_aio_readv(acb->common.bs, sector_num, &acb->qiov, 1,
+ bdrv_aio_pwrite_cb, acb);
+ if (tmp_acb == NULL) {
+ bdrv_aio_pwrite_cb(acb, -EIO);
+ }
+ break;
+ }
+
+ case 4:
+ /* Modify and write last sector */
+ acb->state = 5;
+ memcpy(acb->tmp_buf, acb->buf, acb->bytes);
+ tmp_acb = bdrv_aio_writev(acb->common.bs, sector_num, &acb->qiov, 1,
+ bdrv_aio_pwrite_cb, acb);
+ if (tmp_acb == NULL) {
+ bdrv_aio_pwrite_cb(acb, -EIO);
+ }
+ break;
+
+ case 5:
+ goto done;
+ }
+ return;
+
+done:
+ qemu_free(acb->tmp_buf);
+ acb->common.cb(acb->common.opaque, ret);
+ qemu_aio_release(acb);
+}
+
+BlockDriverAIOCB *bdrv_aio_pwrite(BlockDriverState *bs, int64_t offset,
+ void* buf, size_t bytes, BlockDriverCompletionFunc *cb, void *opaque)
+{
+ PwriteAIOCB *acb;
+
+ acb = qemu_aio_get(&blkqueue_aio_pool, bs, cb, opaque);
+ acb->state = 0;
+ acb->offset = offset;
+ acb->buf = buf;
+ acb->bytes = bytes;
+ acb->tmp_buf = NULL;
+
+ bdrv_aio_pwrite_cb(acb, 0);
+
+ return &acb->common;
+}
+
typedef struct MultiwriteCB {
int error;
diff --git a/block.h b/block.h
index 78ecfac..c6e4d90 100644
--- a/block.h
+++ b/block.h
@@ -116,6 +116,8 @@ BlockDriverAIOCB *bdrv_aio_readv(BlockDriverState *bs,
int64_t sector_num,
BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num,
QEMUIOVector *iov, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque);
+BlockDriverAIOCB *bdrv_aio_pwrite(BlockDriverState *bs, int64_t offset, void*
buf,
+ size_t bytes, BlockDriverCompletionFunc *cb, void *opaque);
BlockDriverAIOCB *bdrv_aio_flush(BlockDriverState *bs,
BlockDriverCompletionFunc *cb, void *opaque);
void bdrv_aio_cancel(BlockDriverAIOCB *acb);
--
1.7.2.3
