qcow2: Use coroutines
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/qcow2.c b/block/qcow2.c
index 48e1b95..f07d550 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -276,6 +276,9 @@
goto fail;
}
+ /* Initialise locks */
+ qemu_co_mutex_init(&s->lock);
+
#ifdef DEBUG_ALLOC
qcow2_check_refcounts(bs);
#endif
@@ -379,7 +382,6 @@
uint64_t cluster_offset;
uint8_t *cluster_data;
bool is_write;
- BlockDriverAIOCB *hd_aiocb;
QEMUIOVector hd_qiov;
QEMUBH *bh;
QCowL2Meta l2meta;
@@ -389,8 +391,6 @@
static void qcow2_aio_cancel(BlockDriverAIOCB *blockacb)
{
QCowAIOCB *acb = container_of(blockacb, QCowAIOCB, common);
- if (acb->hd_aiocb)
- bdrv_aio_cancel(acb->hd_aiocb);
qemu_aio_release(acb);
}
@@ -399,46 +399,16 @@
.cancel = qcow2_aio_cancel,
};
-static void qcow2_aio_read_cb(void *opaque, int ret);
-static void qcow2_aio_write_cb(void *opaque, int ret);
-
-static void qcow2_aio_rw_bh(void *opaque)
+/*
+ * Returns 0 when the request is completed successfully, 1 when there is still
+ * a part left to do and -errno in error cases.
+ */
+static int qcow2_aio_read_cb(QCowAIOCB *acb)
{
- QCowAIOCB *acb = opaque;
- qemu_bh_delete(acb->bh);
- acb->bh = NULL;
-
- if (acb->is_write) {
- qcow2_aio_write_cb(opaque, 0);
- } else {
- qcow2_aio_read_cb(opaque, 0);
- }
-}
-
-static int qcow2_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 qcow2_aio_read_cb(void *opaque, int ret)
-{
- QCowAIOCB *acb = opaque;
BlockDriverState *bs = acb->common.bs;
BDRVQcowState *s = bs->opaque;
int index_in_cluster, n1;
-
- acb->hd_aiocb = NULL;
- if (ret < 0)
- goto done;
+ int ret;
/* post process the read buffer */
if (!acb->cluster_offset) {
@@ -463,8 +433,7 @@
if (acb->remaining_sectors == 0) {
/* request completed */
- ret = 0;
- goto done;
+ return 0;
}
/* prepare next AIO request */
@@ -477,7 +446,7 @@
ret = qcow2_get_cluster_offset(bs, acb->sector_num << 9,
&acb->cur_nr_sectors, &acb->cluster_offset);
if (ret < 0) {
- goto done;
+ return ret;
}
index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
@@ -494,42 +463,35 @@
acb->sector_num, acb->cur_nr_sectors);
if (n1 > 0) {
BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
- acb->hd_aiocb = bdrv_aio_readv(bs->backing_hd, acb->sector_num,
- &acb->hd_qiov, n1, qcow2_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,
+ n1, &acb->hd_qiov);
+ qemu_co_mutex_lock(&s->lock);
+ if (ret < 0) {
+ return ret;
}
- } else {
- ret = qcow2_schedule_bh(qcow2_aio_rw_bh, acb);
- if (ret < 0)
- goto done;
}
+ return 1;
} else {
/* Note: in this case, no need to wait */
qemu_iovec_memset(&acb->hd_qiov, 0, 512 * acb->cur_nr_sectors);
- ret = qcow2_schedule_bh(qcow2_aio_rw_bh, acb);
- if (ret < 0)
- goto done;
+ return 1;
}
} else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
/* add AIO support for compressed blocks ? */
ret = qcow2_decompress_cluster(bs, acb->cluster_offset);
if (ret < 0) {
- goto done;
+ return ret;
}
qemu_iovec_from_buffer(&acb->hd_qiov,
s->cluster_cache + index_in_cluster * 512,
512 * acb->cur_nr_sectors);
- ret = qcow2_schedule_bh(qcow2_aio_rw_bh, acb);
- if (ret < 0)
- goto done;
+ return 1;
} else {
if ((acb->cluster_offset & 511) != 0) {
- ret = -EIO;
- goto done;
+ return -EIO;
}
if (s->crypt_method) {
@@ -550,21 +512,17 @@
}
BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
- 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->cur_nr_sectors,
- qcow2_aio_read_cb, acb);
- if (acb->hd_aiocb == NULL) {
- ret = -EIO;
- goto done;
+ acb->cur_nr_sectors, &acb->hd_qiov);
+ qemu_co_mutex_lock(&s->lock);
+ if (ret < 0) {
+ return ret;
}
}
- return;
-done:
- acb->common.cb(acb->common.opaque, ret);
- qemu_iovec_destroy(&acb->hd_qiov);
- qemu_aio_release(acb);
+ return 1;
}
static QCowAIOCB *qcow2_aio_setup(BlockDriverState *bs, int64_t sector_num,
@@ -577,7 +535,6 @@
acb = qemu_aio_get(&qcow2_aio_pool, bs, cb, opaque);
if (!acb)
return NULL;
- acb->hd_aiocb = NULL;
acb->sector_num = sector_num;
acb->qiov = qiov;
acb->is_write = is_write;
@@ -589,79 +546,73 @@
acb->cur_nr_sectors = 0;
acb->cluster_offset = 0;
acb->l2meta.nb_clusters = 0;
- QLIST_INIT(&acb->l2meta.dependent_requests);
+ qemu_co_queue_init(&acb->l2meta.dependent_requests);
return acb;
}
-static BlockDriverAIOCB *qcow2_aio_readv(BlockDriverState *bs,
- int64_t sector_num,
- QEMUIOVector *qiov, int nb_sectors,
- BlockDriverCompletionFunc *cb,
- void *opaque)
+static int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num,
+ int nb_sectors, QEMUIOVector *qiov)
{
+ BDRVQcowState *s = bs->opaque;
QCowAIOCB *acb;
int ret;
- acb = qcow2_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
- if (!acb)
- return NULL;
+ acb = qcow2_aio_setup(bs, sector_num, qiov, nb_sectors, NULL, NULL, 0);
- ret = qcow2_schedule_bh(qcow2_aio_rw_bh, acb);
- if (ret < 0) {
- qemu_iovec_destroy(&acb->hd_qiov);
- qemu_aio_release(acb);
- return NULL;
- }
+ qemu_co_mutex_lock(&s->lock);
+ do {
+ ret = qcow2_aio_read_cb(acb);
+ } while (ret > 0);
+ qemu_co_mutex_unlock(&s->lock);
- return &acb->common;
+ qemu_iovec_destroy(&acb->hd_qiov);
+ qemu_aio_release(acb);
+
+ return ret;
}
-static void run_dependent_requests(QCowL2Meta *m)
+static void run_dependent_requests(BDRVQcowState *s, QCowL2Meta *m)
{
- QCowAIOCB *req;
- QCowAIOCB *next;
-
/* Take the request off the list of running requests */
if (m->nb_clusters != 0) {
QLIST_REMOVE(m, next_in_flight);
}
/* Restart all dependent requests */
- QLIST_FOREACH_SAFE(req, &m->dependent_requests, next_depend, next) {
- qcow2_aio_write_cb(req, 0);
+ if (!qemu_co_queue_empty(&m->dependent_requests)) {
+ qemu_co_mutex_unlock(&s->lock);
+ while(qemu_co_queue_next(&m->dependent_requests));
+ qemu_co_mutex_lock(&s->lock);
}
-
- /* Empty the list for the next part of the request */
- QLIST_INIT(&m->dependent_requests);
}
-static void qcow2_aio_write_cb(void *opaque, int ret)
+/*
+ * Returns 0 when the request is completed successfully, 1 when there is still
+ * a part left to do and -errno in error cases.
+ */
+static int qcow2_aio_write_cb(QCowAIOCB *acb)
{
- QCowAIOCB *acb = opaque;
BlockDriverState *bs = acb->common.bs;
BDRVQcowState *s = bs->opaque;
int index_in_cluster;
int n_end;
+ int ret;
- acb->hd_aiocb = NULL;
+ ret = qcow2_alloc_cluster_link_l2(bs, &acb->l2meta);
- if (ret >= 0) {
- ret = qcow2_alloc_cluster_link_l2(bs, &acb->l2meta);
+ run_dependent_requests(s, &acb->l2meta);
+
+ if (ret < 0) {
+ return ret;
}
- run_dependent_requests(&acb->l2meta);
-
- if (ret < 0)
- goto done;
-
acb->remaining_sectors -= acb->cur_nr_sectors;
acb->sector_num += acb->cur_nr_sectors;
acb->bytes_done += acb->cur_nr_sectors * 512;
if (acb->remaining_sectors == 0) {
/* request completed */
- ret = 0;
- goto done;
+ return 0;
}
index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
@@ -673,18 +624,10 @@
ret = qcow2_alloc_cluster_offset(bs, acb->sector_num << 9,
index_in_cluster, n_end, &acb->cur_nr_sectors, &acb->l2meta);
if (ret < 0) {
- goto done;
+ return ret;
}
acb->cluster_offset = acb->l2meta.cluster_offset;
-
- /* Need to wait for another request? If so, we are done for now. */
- if (acb->l2meta.nb_clusters == 0 && acb->l2meta.depends_on != NULL) {
- QLIST_INSERT_HEAD(&acb->l2meta.depends_on->dependent_requests,
- acb, next_depend);
- return;
- }
-
assert((acb->cluster_offset & 511) == 0);
qemu_iovec_reset(&acb->hd_qiov);
@@ -709,51 +652,40 @@
}
BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
- acb->hd_aiocb = bdrv_aio_writev(bs->file,
- (acb->cluster_offset >> 9) + index_in_cluster,
- &acb->hd_qiov, acb->cur_nr_sectors,
- qcow2_aio_write_cb, acb);
- if (acb->hd_aiocb == NULL) {
- ret = -EIO;
- goto fail;
+ qemu_co_mutex_unlock(&s->lock);
+ ret = bdrv_co_writev(bs->file,
+ (acb->cluster_offset >> 9) + index_in_cluster,
+ acb->cur_nr_sectors, &acb->hd_qiov);
+ qemu_co_mutex_lock(&s->lock);
+ if (ret < 0) {
+ return ret;
}
- return;
-
-fail:
- if (acb->l2meta.nb_clusters != 0) {
- QLIST_REMOVE(&acb->l2meta, next_in_flight);
- }
-done:
- acb->common.cb(acb->common.opaque, ret);
- qemu_iovec_destroy(&acb->hd_qiov);
- qemu_aio_release(acb);
+ return 1;
}
-static BlockDriverAIOCB *qcow2_aio_writev(BlockDriverState *bs,
- int64_t sector_num,
- QEMUIOVector *qiov, int nb_sectors,
- BlockDriverCompletionFunc *cb,
- void *opaque)
+static int qcow2_co_writev(BlockDriverState *bs,
+ int64_t sector_num,
+ int nb_sectors,
+ QEMUIOVector *qiov)
{
BDRVQcowState *s = bs->opaque;
QCowAIOCB *acb;
int ret;
+ acb = qcow2_aio_setup(bs, sector_num, qiov, nb_sectors, NULL, NULL, 1);
s->cluster_cache_offset = -1; /* disable compressed cache */
- acb = qcow2_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
- if (!acb)
- return NULL;
+ qemu_co_mutex_lock(&s->lock);
+ do {
+ ret = qcow2_aio_write_cb(acb);
+ } while (ret > 0);
+ qemu_co_mutex_unlock(&s->lock);
- ret = qcow2_schedule_bh(qcow2_aio_rw_bh, acb);
- if (ret < 0) {
- qemu_iovec_destroy(&acb->hd_qiov);
- qemu_aio_release(acb);
- return NULL;
- }
+ qemu_iovec_destroy(&acb->hd_qiov);
+ qemu_aio_release(acb);
- return &acb->common;
+ return ret;
}
static void qcow2_close(BlockDriverState *bs)
@@ -881,7 +813,7 @@
nb_sectors = bdrv_getlength(bs) >> 9;
offset = 0;
- QLIST_INIT(&meta.dependent_requests);
+ qemu_co_queue_init(&meta.dependent_requests);
meta.cluster_offset = 0;
while (nb_sectors) {
@@ -899,7 +831,7 @@
/* There are no dependent requests, but we need to remove our request
* from the list of in-flight requests */
- run_dependent_requests(&meta);
+ run_dependent_requests(bs->opaque, &meta);
/* TODO Preallocate data if requested */
@@ -1387,8 +1319,8 @@
.bdrv_set_key = qcow2_set_key,
.bdrv_make_empty = qcow2_make_empty,
- .bdrv_aio_readv = qcow2_aio_readv,
- .bdrv_aio_writev = qcow2_aio_writev,
+ .bdrv_co_readv = qcow2_co_readv,
+ .bdrv_co_writev = qcow2_co_writev,
.bdrv_aio_flush = qcow2_aio_flush,
.bdrv_discard = qcow2_discard,
