Commit e67a64a8 authored by Kevin Wolf's avatar Kevin Wolf
Browse files

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: default avatarKevin Wolf <kwolf@redhat.com>
parent b11a24de

block/vdi.c

+36 −5
Original line number Diff line number Diff line
@@ -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;
@@ -542,15 +545,21 @@ 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;



    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;

}