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qcow: Use coroutines 

The old qcow format is another user of the AsyncContext infrastructure.
Converting it to coroutines (and therefore CoMutexes) allows to remove
AsyncContexts.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf 2011-07-15 16:27:42 +02:00
parent 68d100e905
commit 52b8eb6013
1 changed files with 65 additions and 121 deletions
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186
block/qcow.c
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@ -73,6 +73,7 @@ typedef struct BDRVQcowState {
uint32_t crypt_method_header;
AES_KEY aes_encrypt_key;
AES_KEY aes_decrypt_key;
CoMutex lock;
} BDRVQcowState;
static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
@ -517,11 +518,11 @@ static AIOPool qcow_aio_pool = {
static QCowAIOCB *qcow_aio_setup(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque, int is_write)
int is_write)
{
QCowAIOCB *acb;
acb = qemu_aio_get(&qcow_aio_pool, bs, cb, opaque);
acb = qemu_aio_get(&qcow_aio_pool, bs, NULL, NULL);
if (!acb)
return NULL;
acb->hd_aiocb = NULL;
@ -542,48 +543,15 @@ static QCowAIOCB *qcow_aio_setup(BlockDriverState *bs,
return acb;
}
static void qcow_aio_read_cb(void *opaque, int ret);
static void qcow_aio_write_cb(void *opaque, int ret);
static void qcow_aio_rw_bh(void *opaque)
{
QCowAIOCB *acb = opaque;
qemu_bh_delete(acb->bh);
acb->bh = NULL;
if (acb->is_write) {
qcow_aio_write_cb(opaque, 0);
} else {
qcow_aio_read_cb(opaque, 0);
}
}
static int qcow_schedule_bh(QEMUBHFunc *cb, QCowAIOCB *acb)
{
if (acb->bh) {
return -EIO;
}
acb->bh = qemu_bh_new(cb, acb);
if (!acb->bh) {
return -EIO;
}
qemu_bh_schedule(acb->bh);
return 0;
}
static void qcow_aio_read_cb(void *opaque, int ret)
static int qcow_aio_read_cb(void *opaque)
{
QCowAIOCB *acb = opaque;
BlockDriverState *bs = acb->common.bs;
BDRVQcowState *s = bs->opaque;
int index_in_cluster;
int ret;
acb->hd_aiocb = NULL;
if (ret < 0)
goto done;
redo:
/* post process the read buffer */
@ -605,8 +573,7 @@ static void qcow_aio_read_cb(void *opaque, int ret)
if (acb->nb_sectors == 0) {
/* request completed */
ret = 0;
goto done;
return 0;
}
/* prepare next AIO request */
@ -623,11 +590,12 @@ static void qcow_aio_read_cb(void *opaque, int ret)
acb->hd_iov.iov_base = (void *)acb->buf;
acb->hd_iov.iov_len = acb->n * 512;
qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
acb->hd_aiocb = bdrv_aio_readv(bs->backing_hd, acb->sector_num,
&acb->hd_qiov, acb->n, qcow_aio_read_cb, acb);
if (acb->hd_aiocb == NULL) {
ret = -EIO;
goto done;
qemu_co_mutex_unlock(&s->lock);
ret = bdrv_co_readv(bs->backing_hd, acb->sector_num,
acb->n, &acb->hd_qiov);
qemu_co_mutex_lock(&s->lock);
if (ret < 0) {
return -EIO;
}
} else {
/* Note: in this case, no need to wait */
@ -637,64 +605,56 @@ static void qcow_aio_read_cb(void *opaque, int ret)
} else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
/* add AIO support for compressed blocks ? */
if (decompress_cluster(bs, acb->cluster_offset) < 0) {
ret = -EIO;
goto done;
return -EIO;
}
memcpy(acb->buf,
s->cluster_cache + index_in_cluster * 512, 512 * acb->n);
goto redo;
} else {
if ((acb->cluster_offset & 511) != 0) {
ret = -EIO;
goto done;
return -EIO;
}
acb->hd_iov.iov_base = (void *)acb->buf;
acb->hd_iov.iov_len = acb->n * 512;
qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
acb->hd_aiocb = bdrv_aio_readv(bs->file,
qemu_co_mutex_unlock(&s->lock);
ret = bdrv_co_readv(bs->file,
(acb->cluster_offset >> 9) + index_in_cluster,
&acb->hd_qiov, acb->n, qcow_aio_read_cb, acb);
if (acb->hd_aiocb == NULL) {
ret = -EIO;
goto done;
acb->n, &acb->hd_qiov);
qemu_co_mutex_lock(&s->lock);
if (ret < 0) {
return ret;
}
}
return;
return 1;
}
static int qcow_co_readv(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, QEMUIOVector *qiov)
{
BDRVQcowState *s = bs->opaque;
QCowAIOCB *acb;
int ret;
acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, 0);
qemu_co_mutex_lock(&s->lock);
do {
ret = qcow_aio_read_cb(acb);
} while (ret > 0);
qemu_co_mutex_unlock(&s->lock);
done:
if (acb->qiov->niov > 1) {
qemu_iovec_from_buffer(acb->qiov, acb->orig_buf, acb->qiov->size);
qemu_vfree(acb->orig_buf);
}
acb->common.cb(acb->common.opaque, ret);
qemu_aio_release(acb);
return ret;
}
static BlockDriverAIOCB *qcow_aio_readv(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque)
{
QCowAIOCB *acb;
int ret;
acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
if (!acb)
return NULL;
ret = qcow_schedule_bh(qcow_aio_rw_bh, acb);
if (ret < 0) {
if (acb->qiov->niov > 1) {
qemu_vfree(acb->orig_buf);
}
qemu_aio_release(acb);
return NULL;
}
return &acb->common;
}
static void qcow_aio_write_cb(void *opaque, int ret)
static int qcow_aio_write_cb(void *opaque)
{
QCowAIOCB *acb = opaque;
BlockDriverState *bs = acb->common.bs;
@ -702,20 +662,17 @@ static void qcow_aio_write_cb(void *opaque, int ret)
int index_in_cluster;
uint64_t cluster_offset;
const uint8_t *src_buf;
int ret;
acb->hd_aiocb = NULL;
if (ret < 0)
goto done;
acb->nb_sectors -= acb->n;
acb->sector_num += acb->n;
acb->buf += acb->n * 512;
if (acb->nb_sectors == 0) {
/* request completed */
ret = 0;
goto done;
return 0;
}
index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
@ -726,16 +683,11 @@ static void qcow_aio_write_cb(void *opaque, int ret)
index_in_cluster,
index_in_cluster + acb->n);
if (!cluster_offset || (cluster_offset & 511) != 0) {
ret = -EIO;
goto done;
return -EIO;
}
if (s->crypt_method) {
if (!acb->cluster_data) {
acb->cluster_data = qemu_mallocz(s->cluster_size);
if (!acb->cluster_data) {
ret = -ENOMEM;
goto done;
}
}
encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf,
acb->n, 1, &s->aes_encrypt_key);
@ -747,26 +699,19 @@ static void qcow_aio_write_cb(void *opaque, int ret)
acb->hd_iov.iov_base = (void *)src_buf;
acb->hd_iov.iov_len = acb->n * 512;
qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
acb->hd_aiocb = bdrv_aio_writev(bs->file,
(cluster_offset >> 9) + index_in_cluster,
&acb->hd_qiov, acb->n,
qcow_aio_write_cb, acb);
if (acb->hd_aiocb == NULL) {
ret = -EIO;
goto done;
qemu_co_mutex_unlock(&s->lock);
ret = bdrv_co_writev(bs->file,
(cluster_offset >> 9) + index_in_cluster,
acb->n, &acb->hd_qiov);
qemu_co_mutex_lock(&s->lock);
if (ret < 0) {
return ret;
}
return;
done:
if (acb->qiov->niov > 1)
qemu_vfree(acb->orig_buf);
acb->common.cb(acb->common.opaque, ret);
qemu_aio_release(acb);
return 1;
}
static BlockDriverAIOCB *qcow_aio_writev(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque)
static int qcow_co_writev(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, QEMUIOVector *qiov)
{
BDRVQcowState *s = bs->opaque;
QCowAIOCB *acb;
@ -774,21 +719,20 @@ static BlockDriverAIOCB *qcow_aio_writev(BlockDriverState *bs,
s->cluster_cache_offset = -1; /* disable compressed cache */
acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
if (!acb)
return NULL;
acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, 1);
qemu_co_mutex_lock(&s->lock);
do {
ret = qcow_aio_write_cb(acb);
} while (ret > 0);
qemu_co_mutex_unlock(&s->lock);
ret = qcow_schedule_bh(qcow_aio_rw_bh, acb);
if (ret < 0) {
if (acb->qiov->niov > 1) {
qemu_vfree(acb->orig_buf);
}
qemu_aio_release(acb);
return NULL;
if (acb->qiov->niov > 1) {
qemu_vfree(acb->orig_buf);
}
qemu_aio_release(acb);
return &acb->common;
return ret;
}
static void qcow_close(BlockDriverState *bs)
@ -1020,8 +964,8 @@ static BlockDriver bdrv_qcow = {
.bdrv_is_allocated = qcow_is_allocated,
.bdrv_set_key = qcow_set_key,
.bdrv_make_empty = qcow_make_empty,
.bdrv_aio_readv = qcow_aio_readv,
.bdrv_aio_writev = qcow_aio_writev,
.bdrv_co_readv = qcow_co_readv,
.bdrv_co_writev = qcow_co_writev,
.bdrv_aio_flush = qcow_aio_flush,
.bdrv_write_compressed = qcow_write_compressed,
.bdrv_get_info = qcow_get_info,