X-Git-Url: https://git.proxmox.com/?a=blobdiff_plain;f=block.c;h=cbd8da5f3bd4e43f651de655b4151b8c4a890bef;hb=10da4a368992a5950abd07673ba8311fbbe667f5;hp=e3e77feee0f60a45139d3f6fd1d09bf7c2c73fe3;hpb=7ad5f33b7d612a12d5ee927b64046ef21e4b5bae;p=mirror_qemu.git diff --git a/block.c b/block.c index e3e77feee0..cbd8da5f3b 100644 --- a/block.c +++ b/block.c @@ -911,10 +911,11 @@ static bool bdrv_child_cb_drained_poll(BdrvChild *child) return bdrv_drain_poll(bs, false, NULL, false); } -static void bdrv_child_cb_drained_end(BdrvChild *child) +static void bdrv_child_cb_drained_end(BdrvChild *child, + int *drained_end_counter) { BlockDriverState *bs = child->opaque; - bdrv_drained_end(bs); + bdrv_drained_end_no_poll(bs, drained_end_counter); } static void bdrv_child_cb_attach(BdrvChild *child) @@ -1706,7 +1707,8 @@ static int bdrv_fill_options(QDict **options, const char *filename, static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q, uint64_t perm, uint64_t shared, - GSList *ignore_children, Error **errp); + GSList *ignore_children, + bool *tighten_restrictions, 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, @@ -1781,18 +1783,43 @@ static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs, * permissions of all its parents. This involves checking whether all necessary * permission changes to child nodes can be performed. * + * Will set *tighten_restrictions to true if and only if new permissions have to + * be taken or currently shared permissions are to be unshared. Otherwise, + * errors are not fatal as long as the caller accepts that the restrictions + * remain tighter than they need to be. The caller still has to abort the + * transaction. + * @tighten_restrictions cannot be used together with @q: When reopening, we may + * encounter fatal errors even though no restrictions are to be tightened. For + * example, changing a node from RW to RO will fail if the WRITE permission is + * to be kept. + * * A call to this function must always be followed by a call to bdrv_set_perm() * or bdrv_abort_perm_update(). */ static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q, uint64_t cumulative_perms, uint64_t cumulative_shared_perms, - GSList *ignore_children, Error **errp) + GSList *ignore_children, + bool *tighten_restrictions, Error **errp) { BlockDriver *drv = bs->drv; BdrvChild *c; int ret; + assert(!q || !tighten_restrictions); + + if (tighten_restrictions) { + uint64_t current_perms, current_shared; + uint64_t added_perms, removed_shared_perms; + + bdrv_get_cumulative_perm(bs, ¤t_perms, ¤t_shared); + + added_perms = cumulative_perms & ~current_perms; + removed_shared_perms = current_shared & ~cumulative_shared_perms; + + *tighten_restrictions = added_perms || removed_shared_perms; + } + /* Write permissions never work with read-only images */ if ((cumulative_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) && !bdrv_is_writable_after_reopen(bs, q)) @@ -1833,11 +1860,18 @@ static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q, /* Check all children */ QLIST_FOREACH(c, &bs->children, next) { uint64_t cur_perm, cur_shared; + bool child_tighten_restr; + bdrv_child_perm(bs, c->bs, c, c->role, q, cumulative_perms, cumulative_shared_perms, &cur_perm, &cur_shared); - ret = bdrv_child_check_perm(c, q, cur_perm, cur_shared, - ignore_children, errp); + ret = bdrv_child_check_perm(c, q, cur_perm, cur_shared, ignore_children, + tighten_restrictions ? &child_tighten_restr + : NULL, + errp); + if (tighten_restrictions) { + *tighten_restrictions |= child_tighten_restr; + } if (ret < 0) { return ret; } @@ -1961,17 +1995,23 @@ char *bdrv_perm_names(uint64_t perm) * set, the BdrvChild objects in this list are ignored in the calculations; * this allows checking permission updates for an existing reference. * + * See bdrv_check_perm() for the semantics of @tighten_restrictions. + * * Needs to be followed by a call to either bdrv_set_perm() or * bdrv_abort_perm_update(). */ static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q, uint64_t new_used_perm, uint64_t new_shared_perm, - GSList *ignore_children, Error **errp) + GSList *ignore_children, + bool *tighten_restrictions, + Error **errp) { BdrvChild *c; uint64_t cumulative_perms = new_used_perm; uint64_t cumulative_shared_perms = new_shared_perm; + assert(!q || !tighten_restrictions); + /* There is no reason why anyone couldn't tolerate write_unchanged */ assert(new_shared_perm & BLK_PERM_WRITE_UNCHANGED); @@ -1983,6 +2023,11 @@ static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q, if ((new_used_perm & c->shared_perm) != new_used_perm) { char *user = bdrv_child_user_desc(c); char *perm_names = bdrv_perm_names(new_used_perm & ~c->shared_perm); + + if (tighten_restrictions) { + *tighten_restrictions = true; + } + error_setg(errp, "Conflicts with use by %s as '%s', which does not " "allow '%s' on %s", user, c->name, perm_names, bdrv_get_node_name(c->bs)); @@ -1994,6 +2039,11 @@ static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q, if ((c->perm & new_shared_perm) != c->perm) { char *user = bdrv_child_user_desc(c); char *perm_names = bdrv_perm_names(c->perm & ~new_shared_perm); + + if (tighten_restrictions) { + *tighten_restrictions = true; + } + error_setg(errp, "Conflicts with use by %s as '%s', which uses " "'%s' on %s", user, c->name, perm_names, bdrv_get_node_name(c->bs)); @@ -2007,19 +2057,21 @@ static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q, } return bdrv_check_perm(bs, q, cumulative_perms, cumulative_shared_perms, - ignore_children, errp); + ignore_children, tighten_restrictions, errp); } /* Needs to be followed by a call to either bdrv_child_set_perm() or * bdrv_child_abort_perm_update(). */ static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q, uint64_t perm, uint64_t shared, - GSList *ignore_children, Error **errp) + GSList *ignore_children, + bool *tighten_restrictions, Error **errp) { int ret; ignore_children = g_slist_prepend(g_slist_copy(ignore_children), c); - ret = bdrv_check_update_perm(c->bs, q, perm, shared, ignore_children, errp); + ret = bdrv_check_update_perm(c->bs, q, perm, shared, ignore_children, + tighten_restrictions, errp); g_slist_free(ignore_children); if (ret < 0) { @@ -2070,11 +2122,26 @@ static void bdrv_child_abort_perm_update(BdrvChild *c) int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, Error **errp) { + Error *local_err = NULL; int ret; + bool tighten_restrictions; - ret = bdrv_child_check_perm(c, NULL, perm, shared, NULL, errp); + ret = bdrv_child_check_perm(c, NULL, perm, shared, NULL, + &tighten_restrictions, &local_err); if (ret < 0) { bdrv_child_abort_perm_update(c); + if (tighten_restrictions) { + error_propagate(errp, local_err); + } else { + /* + * Our caller may intend to only loosen restrictions and + * does not expect this function to fail. Errors are not + * fatal in such a case, so we can just hide them from our + * caller. + */ + error_free(local_err); + ret = 0; + } return ret; } @@ -2083,6 +2150,18 @@ int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, return 0; } +int bdrv_child_refresh_perms(BlockDriverState *bs, BdrvChild *c, Error **errp) +{ + uint64_t parent_perms, parent_shared; + uint64_t perms, shared; + + bdrv_get_cumulative_perm(bs, &parent_perms, &parent_shared); + bdrv_child_perm(bs, c->bs, c, c->role, NULL, parent_perms, parent_shared, + &perms, &shared); + + return bdrv_child_try_set_perm(c, perms, shared, errp); +} + void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c, const BdrvChildRole *role, BlockReopenQueue *reopen_queue, @@ -2173,24 +2252,19 @@ static void bdrv_replace_child_noperm(BdrvChild *child, if (child->role->detach) { child->role->detach(child); } - if (old_bs->quiesce_counter && child->role->drained_end) { - 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); - } + while (child->parent_quiesce_counter) { + bdrv_parent_drained_end_single(child); } QLIST_REMOVE(child, next_parent); + } else { + assert(child->parent_quiesce_counter == 0); } child->bs = new_bs; if (new_bs) { QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent); - if (new_bs->quiesce_counter && child->role->drained_begin) { + if (new_bs->quiesce_counter) { int num = new_bs->quiesce_counter; if (child->role->parent_is_bds) { num -= bdrv_drain_all_count; @@ -2228,23 +2302,41 @@ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs) bdrv_replace_child_noperm(child, new_bs); + /* + * Start with the new node's permissions. If @new_bs is a (direct + * or indirect) child of @old_bs, we must complete the permission + * update on @new_bs before we loosen the restrictions on @old_bs. + * Otherwise, bdrv_check_perm() on @old_bs would re-initiate + * updating the permissions of @new_bs, and thus not purely loosen + * restrictions. + */ + if (new_bs) { + bdrv_get_cumulative_perm(new_bs, &perm, &shared_perm); + bdrv_set_perm(new_bs, perm, shared_perm); + } + if (old_bs) { /* Update permissions for old node. This is guaranteed to succeed * because we're just taking a parent away, so we're loosening * restrictions. */ + bool tighten_restrictions; + int ret; + bdrv_get_cumulative_perm(old_bs, &perm, &shared_perm); - bdrv_check_perm(old_bs, NULL, perm, shared_perm, NULL, &error_abort); - bdrv_set_perm(old_bs, perm, shared_perm); + ret = bdrv_check_perm(old_bs, NULL, perm, shared_perm, NULL, + &tighten_restrictions, NULL); + assert(tighten_restrictions == false); + if (ret < 0) { + /* We only tried to loosen restrictions, so errors are not fatal */ + bdrv_abort_perm_update(old_bs); + } else { + bdrv_set_perm(old_bs, perm, shared_perm); + } /* When the parent requiring a non-default AioContext is removed, the * node moves back to the main AioContext */ bdrv_try_set_aio_context(old_bs, qemu_get_aio_context(), NULL); } - - if (new_bs) { - bdrv_get_cumulative_perm(new_bs, &perm, &shared_perm); - bdrv_set_perm(new_bs, perm, shared_perm); - } } /* @@ -2268,7 +2360,8 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, Error *local_err = NULL; int ret; - ret = bdrv_check_update_perm(child_bs, NULL, perm, shared_perm, NULL, errp); + ret = bdrv_check_update_perm(child_bs, NULL, perm, shared_perm, NULL, NULL, + errp); if (ret < 0) { bdrv_abort_perm_update(child_bs); bdrv_unref(child_bs); @@ -2375,18 +2468,20 @@ void bdrv_root_unref_child(BdrvChild *child) bdrv_unref(child_bs); } -void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child) +/** + * Clear all inherits_from pointers from children and grandchildren of + * @root that point to @root, where necessary. + */ +static void bdrv_unset_inherits_from(BlockDriverState *root, BdrvChild *child) { - if (child == NULL) { - return; - } - - if (child->bs->inherits_from == parent) { - BdrvChild *c; + BdrvChild *c; - /* Remove inherits_from only when the last reference between parent and - * child->bs goes away. */ - QLIST_FOREACH(c, &parent->children, next) { + if (child->bs->inherits_from == root) { + /* + * Remove inherits_from only when the last reference between root and + * child->bs goes away. + */ + QLIST_FOREACH(c, &root->children, next) { if (c != child && c->bs == child->bs) { break; } @@ -2396,6 +2491,18 @@ void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child) } } + QLIST_FOREACH(c, &child->bs->children, next) { + bdrv_unset_inherits_from(root, c); + } +} + +void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child) +{ + if (child == NULL) { + return; + } + + bdrv_unset_inherits_from(parent, child); bdrv_root_unref_child(child); } @@ -3349,7 +3456,7 @@ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp) QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { BDRVReopenState *state = &bs_entry->state; ret = bdrv_check_perm(state->bs, bs_queue, state->perm, - state->shared_perm, NULL, errp); + state->shared_perm, NULL, NULL, errp); if (ret < 0) { goto cleanup_perm; } @@ -3361,7 +3468,7 @@ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp) state->perm, state->shared_perm, &nperm, &nshared); ret = bdrv_check_update_perm(state->new_backing_bs, NULL, - nperm, nshared, NULL, errp); + nperm, nshared, NULL, NULL, errp); if (ret < 0) { goto cleanup_perm; } @@ -3905,7 +4012,6 @@ static void bdrv_close(BlockDriverState *bs) BdrvAioNotifier *ban, *ban_next; BdrvChild *child, *next; - assert(!bs->job); assert(!bs->refcnt); bdrv_drained_begin(bs); /* complete I/O */ @@ -4078,7 +4184,7 @@ void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to, /* Check whether the required permissions can be granted on @to, ignoring * all BdrvChild in @list so that they can't block themselves. */ - ret = bdrv_check_update_perm(to, NULL, perm, shared, list, errp); + ret = bdrv_check_update_perm(to, NULL, perm, shared, list, NULL, errp); if (ret < 0) { bdrv_abort_perm_update(to); goto out; @@ -4146,7 +4252,6 @@ out: static void bdrv_delete(BlockDriverState *bs) { - assert(!bs->job); assert(bdrv_op_blocker_is_empty(bs)); assert(!bs->refcnt); @@ -4321,6 +4426,14 @@ int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base, return -EPERM; } + for (i = bs; i != base; i = backing_bs(i)) { + if (i->backing && backing_bs(i)->never_freeze) { + error_setg(errp, "Cannot freeze '%s' link to '%s'", + i->backing->name, backing_bs(i)->node_name); + return -EPERM; + } + } + for (i = bs; i != base; i = backing_bs(i)) { if (i->backing) { i->backing->frozen = true; @@ -4426,7 +4539,7 @@ int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base, /* Check whether we are allowed to switch c from top to base */ GSList *ignore_children = g_slist_prepend(NULL, c); ret = bdrv_check_update_perm(base, NULL, c->perm, c->shared_perm, - ignore_children, &local_err); + ignore_children, NULL, &local_err); g_slist_free(ignore_children); if (ret < 0) { error_report_err(local_err); @@ -5201,7 +5314,7 @@ static void coroutine_fn bdrv_co_invalidate_cache(BlockDriverState *bs, */ bs->open_flags &= ~BDRV_O_INACTIVE; bdrv_get_cumulative_perm(bs, &perm, &shared_perm); - ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, &local_err); + ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, NULL, &local_err); if (ret < 0) { bs->open_flags |= BDRV_O_INACTIVE; error_propagate(errp, local_err); @@ -5315,6 +5428,7 @@ static bool bdrv_has_bds_parent(BlockDriverState *bs, bool only_active) static int bdrv_inactivate_recurse(BlockDriverState *bs) { BdrvChild *child, *parent; + bool tighten_restrictions; uint64_t perm, shared_perm; int ret; @@ -5351,8 +5465,15 @@ static int bdrv_inactivate_recurse(BlockDriverState *bs) /* Update permissions, they may differ for inactive nodes */ bdrv_get_cumulative_perm(bs, &perm, &shared_perm); - bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, &error_abort); - bdrv_set_perm(bs, perm, shared_perm); + ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, + &tighten_restrictions, NULL); + assert(tighten_restrictions == false); + if (ret < 0) { + /* We only tried to loosen restrictions, so errors are not fatal */ + bdrv_abort_perm_update(bs); + } else { + bdrv_set_perm(bs, perm, shared_perm); + } /* Recursively inactivate children */ @@ -5793,6 +5914,8 @@ static void bdrv_attach_aio_context(BlockDriverState *bs, * Changes the AioContext used for fd handlers, timers, and BHs by this * BlockDriverState and all its children and parents. * + * Must be called from the main AioContext. + * * 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). @@ -5803,9 +5926,12 @@ static void bdrv_attach_aio_context(BlockDriverState *bs, void bdrv_set_aio_context_ignore(BlockDriverState *bs, AioContext *new_context, GSList **ignore) { + AioContext *old_context = bdrv_get_aio_context(bs); BdrvChild *child; - if (bdrv_get_aio_context(bs) == new_context) { + g_assert(qemu_get_current_aio_context() == qemu_get_aio_context()); + + if (old_context == new_context) { return; } @@ -5829,13 +5955,31 @@ void bdrv_set_aio_context_ignore(BlockDriverState *bs, bdrv_detach_aio_context(bs); - /* This function executes in the old AioContext so acquire the new one in - * case it runs in a different thread. - */ - aio_context_acquire(new_context); + /* Acquire the new context, if necessary */ + if (qemu_get_aio_context() != new_context) { + aio_context_acquire(new_context); + } + bdrv_attach_aio_context(bs, new_context); + + /* + * If this function was recursively called from + * bdrv_set_aio_context_ignore(), there may be nodes in the + * subtree that have not yet been moved to the new AioContext. + * Release the old one so bdrv_drained_end() can poll them. + */ + if (qemu_get_aio_context() != old_context) { + aio_context_release(old_context); + } + bdrv_drained_end(bs); - aio_context_release(new_context); + + if (qemu_get_aio_context() != old_context) { + aio_context_acquire(old_context); + } + if (qemu_get_aio_context() != new_context) { + aio_context_release(new_context); + } } static bool bdrv_parent_can_set_aio_context(BdrvChild *c, AioContext *ctx,