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vdi: Avoid direct AIO callback 

bdrv_aio_* must not call the callback before returning to its caller. In vdi,
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 16:12:58 +02:00
parent b11a24dee6
commit e67a64a869
1 changed files with 36 additions and 5 deletions
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41
block/vdi.c
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@ -152,6 +152,7 @@ typedef struct {
/* Buffer for new allocated block. */
void *block_buffer;
void *orig_buf;
bool is_write;
int header_modified;
BlockDriverAIOCB *hd_aiocb;
struct iovec hd_iov;
@ -504,6 +505,8 @@ static VdiAIOCB *vdi_aio_setup(BlockDriverState *bs, int64_t sector_num,
acb->hd_aiocb = NULL;
acb->sector_num = sector_num;
acb->qiov = qiov;
acb->is_write = is_write;
if (qiov->niov > 1) {
acb->buf = qemu_blockalign(bs, qiov->size);
acb->orig_buf = acb->buf;
@ -542,14 +545,20 @@ static int vdi_schedule_bh(QEMUBHFunc *cb, VdiAIOCB *acb)
}
static void vdi_aio_read_cb(void *opaque, int ret);
static void vdi_aio_write_cb(void *opaque, int ret);
static void vdi_aio_read_bh(void *opaque)
static void vdi_aio_rw_bh(void *opaque)
{
VdiAIOCB *acb = opaque;
logout("\n");
qemu_bh_delete(acb->bh);
acb->bh = NULL;
vdi_aio_read_cb(opaque, 0);
if (acb->is_write) {
vdi_aio_write_cb(opaque, 0);
} else {
vdi_aio_read_cb(opaque, 0);
}
}
static void vdi_aio_read_cb(void *opaque, int ret)
@ -597,7 +606,7 @@ static void vdi_aio_read_cb(void *opaque, int ret)
if (bmap_entry == VDI_UNALLOCATED) {
/* Block not allocated, return zeros, no need to wait. */
memset(acb->buf, 0, n_sectors * SECTOR_SIZE);
ret = vdi_schedule_bh(vdi_aio_read_bh, acb);
ret = vdi_schedule_bh(vdi_aio_rw_bh, acb);
if (ret < 0) {
goto done;
}
@ -630,12 +639,23 @@ static BlockDriverAIOCB *vdi_aio_readv(BlockDriverState *bs,
BlockDriverCompletionFunc *cb, void *opaque)
{
VdiAIOCB *acb;
int ret;
logout("\n");
acb = vdi_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
if (!acb) {
return NULL;
}
vdi_aio_read_cb(acb, 0);
ret = vdi_schedule_bh(vdi_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;
}
@ -789,12 +809,23 @@ static BlockDriverAIOCB *vdi_aio_writev(BlockDriverState *bs,
BlockDriverCompletionFunc *cb, void *opaque)
{
VdiAIOCB *acb;
int ret;
logout("\n");
acb = vdi_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
if (!acb) {
return NULL;
}
vdi_aio_write_cb(acb, 0);
ret = vdi_schedule_bh(vdi_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;
}