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qcow2: Avoid direct AIO callback

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bdrv_aio_* must not call the callback before returning to its caller. In qcow2,
this could happen in some error cases. This starts the real requests processing
in a BH to avoid this situation.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf 2011-06-07 15:04:32 +02:00
parent 7bf4162a80
commit 42496d6240
1 changed files with 30 additions and 9 deletions
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39
block/qcow2.c
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@ -378,6 +378,7 @@ typedef struct QCowAIOCB {
uint64_t bytes_done; uint64_t bytes_done;
uint64_t cluster_offset; uint64_t cluster_offset;
uint8_t *cluster_data; uint8_t *cluster_data;
bool is_write;
BlockDriverAIOCB *hd_aiocb; BlockDriverAIOCB *hd_aiocb;
QEMUIOVector hd_qiov; QEMUIOVector hd_qiov;
QEMUBH *bh; QEMUBH *bh;
@ -399,12 +400,19 @@ static AIOPool qcow2_aio_pool = {
}; };
static void qcow2_aio_read_cb(void *opaque, int ret); static void qcow2_aio_read_cb(void *opaque, int ret);
static void qcow2_aio_read_bh(void *opaque) static void qcow2_aio_write_cb(void *opaque, int ret);
static void qcow2_aio_rw_bh(void *opaque)
{ {
QCowAIOCB *acb = opaque; QCowAIOCB *acb = opaque;
qemu_bh_delete(acb->bh); qemu_bh_delete(acb->bh);
acb->bh = NULL; acb->bh = NULL;
qcow2_aio_read_cb(opaque, 0);
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) static int qcow2_schedule_bh(QEMUBHFunc *cb, QCowAIOCB *acb)
@ -493,14 +501,14 @@ static void qcow2_aio_read_cb(void *opaque, int ret)
goto done; goto done;
} }
} else { } else {
ret = qcow2_schedule_bh(qcow2_aio_read_bh, acb); ret = qcow2_schedule_bh(qcow2_aio_rw_bh, acb);
if (ret < 0) if (ret < 0)
goto done; goto done;
} }
} else { } else {
/* Note: in this case, no need to wait */ /* Note: in this case, no need to wait */
qemu_iovec_memset(&acb->hd_qiov, 0, 512 * acb->cur_nr_sectors); qemu_iovec_memset(&acb->hd_qiov, 0, 512 * acb->cur_nr_sectors);
ret = qcow2_schedule_bh(qcow2_aio_read_bh, acb); ret = qcow2_schedule_bh(qcow2_aio_rw_bh, acb);
if (ret < 0) if (ret < 0)
goto done; goto done;
} }
@ -515,7 +523,7 @@ static void qcow2_aio_read_cb(void *opaque, int ret)
s->cluster_cache + index_in_cluster * 512, s->cluster_cache + index_in_cluster * 512,
512 * acb->cur_nr_sectors); 512 * acb->cur_nr_sectors);
ret = qcow2_schedule_bh(qcow2_aio_read_bh, acb); ret = qcow2_schedule_bh(qcow2_aio_rw_bh, acb);
if (ret < 0) if (ret < 0)
goto done; goto done;
} else { } else {
@ -572,6 +580,7 @@ static QCowAIOCB *qcow2_aio_setup(BlockDriverState *bs, int64_t sector_num,
acb->hd_aiocb = NULL; acb->hd_aiocb = NULL;
acb->sector_num = sector_num; acb->sector_num = sector_num;
acb->qiov = qiov; acb->qiov = qiov;
acb->is_write = is_write;
qemu_iovec_init(&acb->hd_qiov, qiov->niov); qemu_iovec_init(&acb->hd_qiov, qiov->niov);
@ -591,17 +600,22 @@ static BlockDriverAIOCB *qcow2_aio_readv(BlockDriverState *bs,
void *opaque) void *opaque)
{ {
QCowAIOCB *acb; QCowAIOCB *acb;
int ret;
acb = qcow2_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0); acb = qcow2_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
if (!acb) if (!acb)
return NULL; return NULL;
qcow2_aio_read_cb(acb, 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;
}
return &acb->common; return &acb->common;
} }
static void qcow2_aio_write_cb(void *opaque, int ret);
static void run_dependent_requests(QCowL2Meta *m) static void run_dependent_requests(QCowL2Meta *m)
{ {
QCowAIOCB *req; QCowAIOCB *req;
@ -724,6 +738,7 @@ static BlockDriverAIOCB *qcow2_aio_writev(BlockDriverState *bs,
{ {
BDRVQcowState *s = bs->opaque; BDRVQcowState *s = bs->opaque;
QCowAIOCB *acb; QCowAIOCB *acb;
int ret;
s->cluster_cache_offset = -1; /* disable compressed cache */ s->cluster_cache_offset = -1; /* disable compressed cache */
@ -731,7 +746,13 @@ static BlockDriverAIOCB *qcow2_aio_writev(BlockDriverState *bs,
if (!acb) if (!acb)
return NULL; return NULL;
qcow2_aio_write_cb(acb, 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;
}
return &acb->common; return &acb->common;
} }