Commit e3442099 authored by Stefan Hajnoczi's avatar Stefan Hajnoczi Committed by Kevin Wolf
Browse files

blockdev: acquire AioContext in eject, change, and block_passwd 



By acquiring the AioContext we avoid race conditions with the dataplane
thread which may also be accessing the BlockDriverState.

Fix up eject, change, and block_passwd in a single patch because
qmp_eject() and qmp_change_blockdev() both call eject_device().  Also
fix block_passwd while we're tackling a command that takes a block
encryption password.

Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 0b928854

blockdev.c

+29 −7
Original line number Diff line number Diff line
@@ -1617,14 +1617,18 @@ exit: 
static void eject_device(BlockBackend *blk, int force, Error **errp)

{

    BlockDriverState *bs = blk_bs(blk);

    AioContext *aio_context;



    aio_context = bdrv_get_aio_context(bs);

    aio_context_acquire(aio_context);



    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_EJECT, errp)) {

        return;

        goto out;

    }

    if (!blk_dev_has_removable_media(blk)) {

        error_setg(errp, "Device '%s' is not removable",

                   bdrv_get_device_name(bs));

        return;

        goto out;

    }



    if (blk_dev_is_medium_locked(blk) && !blk_dev_is_tray_open(blk)) {
@@ -1632,11 +1636,14 @@ static void eject_device(BlockBackend *blk, int force, Error **errp) 
        if (!force) {

            error_setg(errp, "Device '%s' is locked",

                       bdrv_get_device_name(bs));

            return;

            goto out;

        }

    }



    bdrv_close(bs);



out:

    aio_context_release(aio_context);

}



void qmp_eject(const char *device, bool has_force, bool force, Error **errp)
@@ -1658,6 +1665,7 @@ void qmp_block_passwd(bool has_device, const char *device, 
{

    Error *local_err = NULL;

    BlockDriverState *bs;

    AioContext *aio_context;

    int err;



    bs = bdrv_lookup_bs(has_device ? device : NULL,
@@ -1668,16 +1676,23 @@ void qmp_block_passwd(bool has_device, const char *device, 
        return;

    }



    aio_context = bdrv_get_aio_context(bs);

    aio_context_acquire(aio_context);



    err = bdrv_set_key(bs, password);

    if (err == -EINVAL) {

        error_set(errp, QERR_DEVICE_NOT_ENCRYPTED, bdrv_get_device_name(bs));

        return;

        goto out;

    } else if (err < 0) {

        error_set(errp, QERR_INVALID_PASSWORD);

        return;

        goto out;

    }



out:

    aio_context_release(aio_context);

}



/* Assumes AioContext is held */

static void qmp_bdrv_open_encrypted(BlockDriverState *bs, const char *filename,

                                    int bdrv_flags, BlockDriver *drv,

                                    const char *password, Error **errp)
@@ -1710,6 +1725,7 @@ void qmp_change_blockdev(const char *device, const char *filename, 
{

    BlockBackend *blk;

    BlockDriverState *bs;

    AioContext *aio_context;

    BlockDriver *drv = NULL;

    int bdrv_flags;

    Error *err = NULL;
@@ -1721,24 +1737,30 @@ void qmp_change_blockdev(const char *device, const char *filename, 
    }

    bs = blk_bs(blk);



    aio_context = bdrv_get_aio_context(bs);

    aio_context_acquire(aio_context);



    if (format) {

        drv = bdrv_find_whitelisted_format(format, bs->read_only);

        if (!drv) {

            error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);

            return;

            goto out;

        }

    }



    eject_device(blk, 0, &err);

    if (err) {

        error_propagate(errp, err);

        return;

        goto out;

    }



    bdrv_flags = bdrv_is_read_only(bs) ? 0 : BDRV_O_RDWR;

    bdrv_flags |= bdrv_is_snapshot(bs) ? BDRV_O_SNAPSHOT : 0;



    qmp_bdrv_open_encrypted(bs, filename, bdrv_flags, drv, NULL, errp);



out:

    aio_context_release(aio_context);

}



/* throttling disk I/O limits */

hw/block/dataplane/virtio-blk.c

+1 −0
Original line number Diff line number Diff line
@@ -198,6 +198,7 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *conf, 
    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_DRIVE_DEL, s->blocker);

    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_BACKUP_SOURCE, s->blocker);

    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_COMMIT, s->blocker);

    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_EJECT, s->blocker);

    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,

                   s->blocker);

    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_MIRROR, s->blocker);