diff options
Diffstat (limited to 'block.c')
| -rw-r--r-- | block.c | 96 |
1 files changed, 80 insertions, 16 deletions
@@ -333,6 +333,10 @@ BlockDriverState *bdrv_new(void) qemu_co_queue_init(&bs->flush_queue); + for (i = 0; i < bdrv_drain_all_count; i++) { + bdrv_drained_begin(bs); + } + QTAILQ_INSERT_TAIL(&all_bdrv_states, bs, bs_list); return bs; @@ -818,7 +822,13 @@ static char *bdrv_child_get_parent_desc(BdrvChild *c) static void bdrv_child_cb_drained_begin(BdrvChild *child) { BlockDriverState *bs = child->opaque; - bdrv_drained_begin(bs); + bdrv_do_drained_begin_quiesce(bs, NULL, false); +} + +static bool bdrv_child_cb_drained_poll(BdrvChild *child) +{ + BlockDriverState *bs = child->opaque; + return bdrv_drain_poll(bs, false, NULL, false); } static void bdrv_child_cb_drained_end(BdrvChild *child) @@ -902,9 +912,11 @@ static void bdrv_inherited_options(int *child_flags, QDict *child_options, } const BdrvChildRole child_file = { + .parent_is_bds = true, .get_parent_desc = bdrv_child_get_parent_desc, .inherit_options = bdrv_inherited_options, .drained_begin = bdrv_child_cb_drained_begin, + .drained_poll = bdrv_child_cb_drained_poll, .drained_end = bdrv_child_cb_drained_end, .attach = bdrv_child_cb_attach, .detach = bdrv_child_cb_detach, @@ -926,9 +938,11 @@ static void bdrv_inherited_fmt_options(int *child_flags, QDict *child_options, } const BdrvChildRole child_format = { + .parent_is_bds = true, .get_parent_desc = bdrv_child_get_parent_desc, .inherit_options = bdrv_inherited_fmt_options, .drained_begin = bdrv_child_cb_drained_begin, + .drained_poll = bdrv_child_cb_drained_poll, .drained_end = bdrv_child_cb_drained_end, .attach = bdrv_child_cb_attach, .detach = bdrv_child_cb_detach, @@ -1043,11 +1057,13 @@ static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base, } const BdrvChildRole child_backing = { + .parent_is_bds = true, .get_parent_desc = bdrv_child_get_parent_desc, .attach = bdrv_backing_attach, .detach = bdrv_backing_detach, .inherit_options = bdrv_backing_options, .drained_begin = bdrv_child_cb_drained_begin, + .drained_poll = bdrv_child_cb_drained_poll, .drained_end = bdrv_child_cb_drained_end, .inactivate = bdrv_child_cb_inactivate, .update_filename = bdrv_backing_update_filename, @@ -1152,7 +1168,7 @@ static int bdrv_open_driver(BlockDriverState *bs, BlockDriver *drv, int open_flags, Error **errp) { Error *local_err = NULL; - int ret; + int i, ret; bdrv_assign_node_name(bs, node_name, &local_err); if (local_err) { @@ -1200,6 +1216,12 @@ static int bdrv_open_driver(BlockDriverState *bs, BlockDriver *drv, assert(bdrv_min_mem_align(bs) != 0); assert(is_power_of_2(bs->bl.request_alignment)); + for (i = 0; i < bs->quiesce_counter; i++) { + if (drv->bdrv_co_drain_begin) { + drv->bdrv_co_drain_begin(bs); + } + } + return 0; open_failed: bs->drv = NULL; @@ -2021,7 +2043,12 @@ static void bdrv_replace_child_noperm(BdrvChild *child, child->role->detach(child); } if (old_bs->quiesce_counter && child->role->drained_end) { - for (i = 0; i < old_bs->quiesce_counter; i++) { + int num = old_bs->quiesce_counter; + if (child->role->parent_is_bds) { + num -= bdrv_drain_all_count; + } + assert(num >= 0); + for (i = 0; i < num; i++) { child->role->drained_end(child); } } @@ -2033,7 +2060,12 @@ static void bdrv_replace_child_noperm(BdrvChild *child, if (new_bs) { QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent); if (new_bs->quiesce_counter && child->role->drained_begin) { - for (i = 0; i < new_bs->quiesce_counter; i++) { + int num = new_bs->quiesce_counter; + if (child->role->parent_is_bds) { + num -= bdrv_drain_all_count; + } + assert(num >= 0); + for (i = 0; i < num; i++) { child->role->drained_begin(child); } } @@ -3395,16 +3427,39 @@ static bool should_update_child(BdrvChild *c, BlockDriverState *to) return false; } - if (c->role == &child_backing) { - /* If @from is a backing file of @to, ignore the child to avoid - * creating a loop. We only want to change the pointer of other - * parents. */ - QLIST_FOREACH(to_c, &to->children, next) { - if (to_c == c) { - break; - } - } - if (to_c) { + /* If the child @c belongs to the BDS @to, replacing the current + * c->bs by @to would mean to create a loop. + * + * Such a case occurs when appending a BDS to a backing chain. + * For instance, imagine the following chain: + * + * guest device -> node A -> further backing chain... + * + * Now we create a new BDS B which we want to put on top of this + * chain, so we first attach A as its backing node: + * + * node B + * | + * v + * guest device -> node A -> further backing chain... + * + * Finally we want to replace A by B. When doing that, we want to + * replace all pointers to A by pointers to B -- except for the + * pointer from B because (1) that would create a loop, and (2) + * that pointer should simply stay intact: + * + * guest device -> node B + * | + * v + * node A -> further backing chain... + * + * In general, when replacing a node A (c->bs) by a node B (@to), + * if A is a child of B, that means we cannot replace A by B there + * because that would create a loop. Silently detaching A from B + * is also not really an option. So overall just leaving A in + * place there is the most sensible choice. */ + QLIST_FOREACH(to_c, &to->children, next) { + if (to_c == c) { return false; } } @@ -3430,6 +3485,7 @@ void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to, /* Put all parents into @list and calculate their cumulative permissions */ QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) { + assert(c->bs == from); if (!should_update_child(c, to)) { continue; } @@ -4037,6 +4093,14 @@ BlockDriverState *bdrv_next_node(BlockDriverState *bs) return QTAILQ_NEXT(bs, node_list); } +BlockDriverState *bdrv_next_all_states(BlockDriverState *bs) +{ + if (!bs) { + return QTAILQ_FIRST(&all_bdrv_states); + } + return QTAILQ_NEXT(bs, bs_list); +} + const char *bdrv_get_node_name(const BlockDriverState *bs) { return bs->node_name; @@ -4948,7 +5012,7 @@ void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context) AioContext *ctx = bdrv_get_aio_context(bs); aio_disable_external(ctx); - bdrv_parent_drained_begin(bs, NULL); + bdrv_parent_drained_begin(bs, NULL, false); bdrv_drain(bs); /* ensure there are no in-flight requests */ while (aio_poll(ctx, false)) { @@ -4962,7 +5026,7 @@ void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context) */ aio_context_acquire(new_context); bdrv_attach_aio_context(bs, new_context); - bdrv_parent_drained_end(bs, NULL); + bdrv_parent_drained_end(bs, NULL, false); aio_enable_external(ctx); aio_context_release(new_context); } |