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qcow2: Use coroutines

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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf 2011-06-30 17:42:09 +02:00
parent b96e92470a
commit 68d100e905
3 changed files with 102 additions and 169 deletions
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26
block/qcow2-cluster.c
View file

@ -697,12 +697,12 @@ err:
* m->depends_on is set to NULL and the other fields in m are meaningless.
*
* If the cluster is newly allocated, m->nb_clusters is set to the number of
* contiguous clusters that have been allocated. This may be 0 if the request
* conflict with another write request in flight; in this case, m->depends_on
* is set and the remaining fields of m are meaningless.
* contiguous clusters that have been allocated. In this case, the other
* fields of m are valid and contain information about the first allocated
* cluster.
*
* If m->nb_clusters is non-zero, the other fields of m are valid and contain
* information about the first allocated cluster.
* If the request conflicts with another write request in flight, the coroutine
* is queued and will be reentered when the dependency has completed.
*
* Return 0 on success and -errno in error cases
*/
@ -721,6 +721,7 @@ int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
return ret;
}
again:
nb_clusters = size_to_clusters(s, n_end << 9);
nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
@ -792,12 +793,12 @@ int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
}
if (nb_clusters == 0) {
/* Set dependency and wait for a callback */
m->depends_on = old_alloc;
m->nb_clusters = 0;
*num = 0;
goto out_wait_dependency;
/* Wait for the dependency to complete. We need to recheck
* the free/allocated clusters when we continue. */
qemu_co_mutex_unlock(&s->lock);
qemu_co_queue_wait(&old_alloc->dependent_requests);
qemu_co_mutex_lock(&s->lock);
goto again;
}
}
}
@ -834,9 +835,6 @@ out:
return 0;
out_wait_dependency:
return qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
fail:
qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
fail_put:

240
block/qcow2.c
View file

@ -276,6 +276,9 @@ static int qcow2_open(BlockDriverState *bs, int flags)
goto fail;
}
/* Initialise locks */
qemu_co_mutex_init(&s->lock);
#ifdef DEBUG_ALLOC
qcow2_check_refcounts(bs);
#endif
@ -379,7 +382,6 @@ typedef struct QCowAIOCB {
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 @@ typedef struct QCowAIOCB {
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 @@ static AIOPool qcow2_aio_pool = {
.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 @@ static void qcow2_aio_read_cb(void *opaque, int ret)
if (acb->remaining_sectors == 0) {
/* request completed */
ret = 0;
goto done;
return 0;
}
/* prepare next AIO request */
@ -477,7 +446,7 @@ static void qcow2_aio_read_cb(void *opaque, int ret)
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 @@ static void qcow2_aio_read_cb(void *opaque, int ret)
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 @@ static void qcow2_aio_read_cb(void *opaque, int ret)
}
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 @@ static QCowAIOCB *qcow2_aio_setup(BlockDriverState *bs, int64_t sector_num,
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 @@ static QCowAIOCB *qcow2_aio_setup(BlockDriverState *bs, int64_t sector_num,
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 @@ static void qcow2_aio_write_cb(void *opaque, int ret)
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 @@ static void qcow2_aio_write_cb(void *opaque, int ret)
}
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 @@ static int preallocate(BlockDriverState *bs)
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 @@ static int preallocate(BlockDriverState *bs)
/* 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 @@ static BlockDriver bdrv_qcow2 = {
.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,

5
block/qcow2.h
View file

@ -26,6 +26,7 @@
#define BLOCK_QCOW2_H
#include "aes.h"
#include "qemu-coroutine.h"
//#define DEBUG_ALLOC
//#define DEBUG_ALLOC2
@ -114,6 +115,8 @@ typedef struct BDRVQcowState {
int64_t free_cluster_index;
int64_t free_byte_offset;
CoMutex lock;
uint32_t crypt_method; /* current crypt method, 0 if no key yet */
uint32_t crypt_method_header;
AES_KEY aes_encrypt_key;
@ -146,7 +149,7 @@ typedef struct QCowL2Meta
int nb_available;
int nb_clusters;
struct QCowL2Meta *depends_on;
QLIST_HEAD(QCowAioDependencies, QCowAIOCB) dependent_requests;
CoQueue dependent_requests;
QLIST_ENTRY(QCowL2Meta) next_in_flight;
} QCowL2Meta;