diff options
Diffstat (limited to 'block.c')
| -rw-r--r-- | block.c | 81 |
1 files changed, 81 insertions, 0 deletions
@@ -882,6 +882,87 @@ void bdrv_make_anon(BlockDriverState *bs) bs->device_name[0] = '\0'; } +/* + * Add new bs contents at the top of an image chain while the chain is + * live, while keeping required fields on the top layer. + * + * This will modify the BlockDriverState fields, and swap contents + * between bs_new and bs_top. Both bs_new and bs_top are modified. + * + * This function does not create any image files. + */ +void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top) +{ + BlockDriverState tmp; + + /* the new bs must not be in bdrv_states */ + bdrv_make_anon(bs_new); + + tmp = *bs_new; + + /* there are some fields that need to stay on the top layer: */ + + /* dev info */ + tmp.dev_ops = bs_top->dev_ops; + tmp.dev_opaque = bs_top->dev_opaque; + tmp.dev = bs_top->dev; + tmp.buffer_alignment = bs_top->buffer_alignment; + tmp.copy_on_read = bs_top->copy_on_read; + + /* i/o timing parameters */ + tmp.slice_time = bs_top->slice_time; + tmp.slice_start = bs_top->slice_start; + tmp.slice_end = bs_top->slice_end; + tmp.io_limits = bs_top->io_limits; + tmp.io_base = bs_top->io_base; + tmp.throttled_reqs = bs_top->throttled_reqs; + tmp.block_timer = bs_top->block_timer; + tmp.io_limits_enabled = bs_top->io_limits_enabled; + + /* geometry */ + tmp.cyls = bs_top->cyls; + tmp.heads = bs_top->heads; + tmp.secs = bs_top->secs; + tmp.translation = bs_top->translation; + + /* r/w error */ + tmp.on_read_error = bs_top->on_read_error; + tmp.on_write_error = bs_top->on_write_error; + + /* i/o status */ + tmp.iostatus_enabled = bs_top->iostatus_enabled; + tmp.iostatus = bs_top->iostatus; + + /* keep the same entry in bdrv_states */ + pstrcpy(tmp.device_name, sizeof(tmp.device_name), bs_top->device_name); + tmp.list = bs_top->list; + + /* The contents of 'tmp' will become bs_top, as we are + * swapping bs_new and bs_top contents. */ + tmp.backing_hd = bs_new; + pstrcpy(tmp.backing_file, sizeof(tmp.backing_file), bs_top->filename); + + /* swap contents of the fixed new bs and the current top */ + *bs_new = *bs_top; + *bs_top = tmp; + + /* clear the copied fields in the new backing file */ + bdrv_detach_dev(bs_new, bs_new->dev); + + qemu_co_queue_init(&bs_new->throttled_reqs); + memset(&bs_new->io_base, 0, sizeof(bs_new->io_base)); + memset(&bs_new->io_limits, 0, sizeof(bs_new->io_limits)); + bdrv_iostatus_disable(bs_new); + + /* we don't use bdrv_io_limits_disable() for this, because we don't want + * to affect or delete the block_timer, as it has been moved to bs_top */ + bs_new->io_limits_enabled = false; + bs_new->block_timer = NULL; + bs_new->slice_time = 0; + bs_new->slice_start = 0; + bs_new->slice_end = 0; +} + void bdrv_delete(BlockDriverState *bs) { assert(!bs->dev); |