diff options
Diffstat (limited to 'block.c')
| -rw-r--r-- | block.c | 174 |
1 files changed, 158 insertions, 16 deletions
@@ -936,6 +936,20 @@ static int bdrv_child_cb_inactivate(BdrvChild *child) return 0; } +static bool bdrv_child_cb_can_set_aio_ctx(BdrvChild *child, AioContext *ctx, + GSList **ignore, Error **errp) +{ + BlockDriverState *bs = child->opaque; + return bdrv_can_set_aio_context(bs, ctx, ignore, errp); +} + +static void bdrv_child_cb_set_aio_ctx(BdrvChild *child, AioContext *ctx, + GSList **ignore) +{ + BlockDriverState *bs = child->opaque; + return bdrv_set_aio_context_ignore(bs, ctx, ignore); +} + /* * Returns the options and flags that a temporary snapshot should get, based on * the originally requested flags (the originally requested image will have @@ -1003,6 +1017,8 @@ const BdrvChildRole child_file = { .attach = bdrv_child_cb_attach, .detach = bdrv_child_cb_detach, .inactivate = bdrv_child_cb_inactivate, + .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx, + .set_aio_ctx = bdrv_child_cb_set_aio_ctx, }; /* @@ -1029,6 +1045,8 @@ const BdrvChildRole child_format = { .attach = bdrv_child_cb_attach, .detach = bdrv_child_cb_detach, .inactivate = bdrv_child_cb_inactivate, + .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx, + .set_aio_ctx = bdrv_child_cb_set_aio_ctx, }; static void bdrv_backing_attach(BdrvChild *c) @@ -1152,6 +1170,8 @@ const BdrvChildRole child_backing = { .drained_end = bdrv_child_cb_drained_end, .inactivate = bdrv_child_cb_inactivate, .update_filename = bdrv_backing_update_filename, + .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx, + .set_aio_ctx = bdrv_child_cb_set_aio_ctx, }; static int bdrv_open_flags(BlockDriverState *bs, int flags) @@ -1689,6 +1709,8 @@ static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q, GSList *ignore_children, Error **errp); static void bdrv_child_abort_perm_update(BdrvChild *c); static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared); +static void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm, + uint64_t *shared_perm); typedef struct BlockReopenQueueEntry { bool prepared; @@ -1775,7 +1797,20 @@ static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q, if ((cumulative_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) && !bdrv_is_writable_after_reopen(bs, q)) { - error_setg(errp, "Block node is read-only"); + if (!bdrv_is_writable_after_reopen(bs, NULL)) { + error_setg(errp, "Block node is read-only"); + } else { + uint64_t current_perms, current_shared; + bdrv_get_cumulative_perm(bs, ¤t_perms, ¤t_shared); + if (current_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) { + error_setg(errp, "Cannot make block node read-only, there is " + "a writer on it"); + } else { + error_setg(errp, "Cannot make block node read-only and create " + "a writer on it"); + } + } + return -EPERM; } @@ -5666,10 +5701,9 @@ static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier *ban) g_free(ban); } -void bdrv_detach_aio_context(BlockDriverState *bs) +static void bdrv_detach_aio_context(BlockDriverState *bs) { BdrvAioNotifier *baf, *baf_tmp; - BdrvChild *child; assert(!bs->walking_aio_notifiers); bs->walking_aio_notifiers = true; @@ -5688,9 +5722,6 @@ void bdrv_detach_aio_context(BlockDriverState *bs) if (bs->drv && bs->drv->bdrv_detach_aio_context) { bs->drv->bdrv_detach_aio_context(bs); } - QLIST_FOREACH(child, &bs->children, next) { - bdrv_detach_aio_context(child->bs); - } if (bs->quiesce_counter) { aio_enable_external(bs->aio_context); @@ -5698,11 +5729,10 @@ void bdrv_detach_aio_context(BlockDriverState *bs) bs->aio_context = NULL; } -void bdrv_attach_aio_context(BlockDriverState *bs, - AioContext *new_context) +static void bdrv_attach_aio_context(BlockDriverState *bs, + AioContext *new_context) { BdrvAioNotifier *ban, *ban_tmp; - BdrvChild *child; if (bs->quiesce_counter) { aio_disable_external(new_context); @@ -5710,9 +5740,6 @@ void bdrv_attach_aio_context(BlockDriverState *bs, bs->aio_context = new_context; - QLIST_FOREACH(child, &bs->children, next) { - bdrv_attach_aio_context(child->bs, new_context); - } if (bs->drv && bs->drv->bdrv_attach_aio_context) { bs->drv->bdrv_attach_aio_context(bs, new_context); } @@ -5729,16 +5756,36 @@ void bdrv_attach_aio_context(BlockDriverState *bs, bs->walking_aio_notifiers = false; } -/* The caller must own the AioContext lock for the old AioContext of bs, but it - * must not own the AioContext lock for new_context (unless new_context is - * the same as the current context of bs). */ -void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context) +/* @ignore will accumulate all visited BdrvChild object. The caller is + * responsible for freeing the list afterwards. */ +void bdrv_set_aio_context_ignore(BlockDriverState *bs, + AioContext *new_context, GSList **ignore) { + BdrvChild *child; + if (bdrv_get_aio_context(bs) == new_context) { return; } bdrv_drained_begin(bs); + + QLIST_FOREACH(child, &bs->children, next) { + if (g_slist_find(*ignore, child)) { + continue; + } + *ignore = g_slist_prepend(*ignore, child); + bdrv_set_aio_context_ignore(child->bs, new_context, ignore); + } + QLIST_FOREACH(child, &bs->parents, next_parent) { + if (g_slist_find(*ignore, child)) { + continue; + } + if (child->role->set_aio_ctx) { + *ignore = g_slist_prepend(*ignore, child); + child->role->set_aio_ctx(child, new_context, ignore); + } + } + bdrv_detach_aio_context(bs); /* This function executes in the old AioContext so acquire the new one in @@ -5750,6 +5797,101 @@ void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context) aio_context_release(new_context); } +/* The caller must own the AioContext lock for the old AioContext of bs, but it + * must not own the AioContext lock for new_context (unless new_context is + * the same as the current context of bs). */ +void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context) +{ + GSList *ignore_list = NULL; + bdrv_set_aio_context_ignore(bs, new_context, &ignore_list); + g_slist_free(ignore_list); +} + +static bool bdrv_parent_can_set_aio_context(BdrvChild *c, AioContext *ctx, + GSList **ignore, Error **errp) +{ + if (g_slist_find(*ignore, c)) { + return true; + } + *ignore = g_slist_prepend(*ignore, c); + + /* A BdrvChildRole that doesn't handle AioContext changes cannot + * tolerate any AioContext changes */ + if (!c->role->can_set_aio_ctx) { + char *user = bdrv_child_user_desc(c); + error_setg(errp, "Changing iothreads is not supported by %s", user); + g_free(user); + return false; + } + if (!c->role->can_set_aio_ctx(c, ctx, ignore, errp)) { + assert(!errp || *errp); + return false; + } + return true; +} + +bool bdrv_child_can_set_aio_context(BdrvChild *c, AioContext *ctx, + GSList **ignore, Error **errp) +{ + if (g_slist_find(*ignore, c)) { + return true; + } + *ignore = g_slist_prepend(*ignore, c); + return bdrv_can_set_aio_context(c->bs, ctx, ignore, errp); +} + +/* @ignore will accumulate all visited BdrvChild object. The caller is + * responsible for freeing the list afterwards. */ +bool bdrv_can_set_aio_context(BlockDriverState *bs, AioContext *ctx, + GSList **ignore, Error **errp) +{ + BdrvChild *c; + + if (bdrv_get_aio_context(bs) == ctx) { + return true; + } + + QLIST_FOREACH(c, &bs->parents, next_parent) { + if (!bdrv_parent_can_set_aio_context(c, ctx, ignore, errp)) { + return false; + } + } + QLIST_FOREACH(c, &bs->children, next) { + if (!bdrv_child_can_set_aio_context(c, ctx, ignore, errp)) { + return false; + } + } + + return true; +} + +int bdrv_child_try_set_aio_context(BlockDriverState *bs, AioContext *ctx, + BdrvChild *ignore_child, Error **errp) +{ + GSList *ignore; + bool ret; + + ignore = ignore_child ? g_slist_prepend(NULL, ignore_child) : NULL; + ret = bdrv_can_set_aio_context(bs, ctx, &ignore, errp); + g_slist_free(ignore); + + if (!ret) { + return -EPERM; + } + + ignore = ignore_child ? g_slist_prepend(NULL, ignore_child) : NULL; + bdrv_set_aio_context_ignore(bs, ctx, &ignore); + g_slist_free(ignore); + + return 0; +} + +int bdrv_try_set_aio_context(BlockDriverState *bs, AioContext *ctx, + Error **errp) +{ + return bdrv_child_try_set_aio_context(bs, ctx, NULL, errp); +} + void bdrv_add_aio_context_notifier(BlockDriverState *bs, void (*attached_aio_context)(AioContext *new_context, void *opaque), void (*detach_aio_context)(void *opaque), void *opaque) |