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authorPeter Maydell <peter.maydell@linaro.org>2017-03-08 09:47:52 +0000
committerPeter Maydell <peter.maydell@linaro.org>2017-03-08 09:47:52 +0000
commitb64842dee42d6b24d51283e4722140b73be1e222 (patch)
treebf3bc697e005203002392d691784c34813a17cf5 /block.c
parent87467097f8811258cd91d42c141a7bd8492ed08a (diff)
parentb69f00dde490e88d55f5ee731545e690b2dc61f8 (diff)
Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging
Block layer fixes for 2.9.0-rc0 # gpg: Signature made Tue 07 Mar 2017 14:59:18 GMT # gpg: using RSA key 0x7F09B272C88F2FD6 # gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" # Primary key fingerprint: DC3D EB15 9A9A F95D 3D74 56FE 7F09 B272 C88F 2FD6 * remotes/kevin/tags/for-upstream: (27 commits) commit: Don't use error_abort in commit_start block: Don't use error_abort in blk_new_open sheepdog: Support blockdev-add qapi-schema: Rename SocketAddressFlat's variant tcp to inet qapi-schema: Rename GlusterServer to SocketAddressFlat gluster: Plug memory leaks in qemu_gluster_parse_json() gluster: Don't duplicate qapi-util.c's qapi_enum_parse() gluster: Drop assumptions on SocketTransport names sheepdog: Implement bdrv_parse_filename() sheepdog: Use SocketAddress and socket_connect() sheepdog: Report errors in pseudo-filename more usefully sheepdog: Don't truncate long VDI name in _open(), _create() sheepdog: Fix snapshot ID parsing in _open(), _create, _goto() sheepdog: Mark sd_snapshot_delete() lossage FIXME sheepdog: Fix error handling sd_create() sheepdog: Fix error handling in sd_snapshot_delete() sheepdog: Defuse time bomb in sd_open() error handling block: Fix error handling in bdrv_replace_in_backing_chain() block: Handle permission errors in change_parent_backing_link() block: Ignore multiple children in bdrv_check_update_perm() ... Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'block.c')
-rw-r--r--block.c182
1 files changed, 120 insertions, 62 deletions
diff --git a/block.c b/block.c
index fe7bddbe5c..b404ef251a 100644
--- a/block.c
+++ b/block.c
@@ -1403,7 +1403,8 @@ static int bdrv_fill_options(QDict **options, const char *filename,
* or bdrv_abort_perm_update().
*/
static int bdrv_check_perm(BlockDriverState *bs, uint64_t cumulative_perms,
- uint64_t cumulative_shared_perms, Error **errp)
+ uint64_t cumulative_shared_perms,
+ GSList *ignore_children, Error **errp)
{
BlockDriver *drv = bs->drv;
BdrvChild *c;
@@ -1439,7 +1440,8 @@ static int bdrv_check_perm(BlockDriverState *bs, uint64_t cumulative_perms,
drv->bdrv_child_perm(bs, c, c->role,
cumulative_perms, cumulative_shared_perms,
&cur_perm, &cur_shared);
- ret = bdrv_child_check_perm(c, cur_perm, cur_shared, errp);
+ ret = bdrv_child_check_perm(c, cur_perm, cur_shared, ignore_children,
+ errp);
if (ret < 0) {
return ret;
}
@@ -1559,15 +1561,15 @@ static char *bdrv_perm_names(uint64_t perm)
/*
* Checks whether a new reference to @bs can be added if the new user requires
- * @new_used_perm/@new_shared_perm as its permissions. If @ignore_child is set,
- * this old reference is ignored in the calculations; this allows checking
- * permission updates for an existing reference.
+ * @new_used_perm/@new_shared_perm as its permissions. If @ignore_children is
+ * set, the BdrvChild objects in this list are ignored in the calculations;
+ * this allows checking permission updates for an existing reference.
*
* 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, uint64_t new_used_perm,
uint64_t new_shared_perm,
- BdrvChild *ignore_child, Error **errp)
+ GSList *ignore_children, Error **errp)
{
BdrvChild *c;
uint64_t cumulative_perms = new_used_perm;
@@ -1577,7 +1579,7 @@ static int bdrv_check_update_perm(BlockDriverState *bs, uint64_t new_used_perm,
assert(new_shared_perm & BLK_PERM_WRITE_UNCHANGED);
QLIST_FOREACH(c, &bs->parents, next_parent) {
- if (c == ignore_child) {
+ if (g_slist_find(ignore_children, c)) {
continue;
}
@@ -1607,15 +1609,22 @@ static int bdrv_check_update_perm(BlockDriverState *bs, uint64_t new_used_perm,
cumulative_shared_perms &= c->shared_perm;
}
- return bdrv_check_perm(bs, cumulative_perms, cumulative_shared_perms, errp);
+ return bdrv_check_perm(bs, cumulative_perms, cumulative_shared_perms,
+ ignore_children, errp);
}
/* Needs to be followed by a call to either bdrv_child_set_perm() or
* bdrv_child_abort_perm_update(). */
int bdrv_child_check_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
- Error **errp)
+ GSList *ignore_children, Error **errp)
{
- return bdrv_check_update_perm(c->bs, perm, shared, c, errp);
+ int ret;
+
+ ignore_children = g_slist_prepend(g_slist_copy(ignore_children), c);
+ ret = bdrv_check_update_perm(c->bs, perm, shared, ignore_children, errp);
+ g_slist_free(ignore_children);
+
+ return ret;
}
void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared)
@@ -1640,7 +1649,7 @@ int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
{
int ret;
- ret = bdrv_child_check_perm(c, perm, shared, errp);
+ ret = bdrv_child_check_perm(c, perm, shared, NULL, errp);
if (ret < 0) {
bdrv_child_abort_perm_update(c);
return ret;
@@ -1718,11 +1727,10 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
*nshared = shared;
}
-static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs,
- bool check_new_perm)
+static void bdrv_replace_child_noperm(BdrvChild *child,
+ BlockDriverState *new_bs)
{
BlockDriverState *old_bs = child->bs;
- uint64_t perm, shared_perm;
if (old_bs) {
if (old_bs->quiesce_counter && child->role->drained_end) {
@@ -1732,13 +1740,6 @@ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs,
child->role->detach(child);
}
QLIST_REMOVE(child, next_parent);
-
- /* Update permissions for old node. This is guaranteed to succeed
- * because we're just taking a parent away, so we're loosening
- * restrictions. */
- bdrv_get_cumulative_perm(old_bs, &perm, &shared_perm);
- bdrv_check_perm(old_bs, perm, shared_perm, &error_abort);
- bdrv_set_perm(old_bs, perm, shared_perm);
}
child->bs = new_bs;
@@ -1749,15 +1750,35 @@ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs,
child->role->drained_begin(child);
}
+ if (child->role->attach) {
+ child->role->attach(child);
+ }
+ }
+}
+
+static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs,
+ bool check_new_perm)
+{
+ BlockDriverState *old_bs = child->bs;
+ uint64_t 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. */
+ bdrv_get_cumulative_perm(old_bs, &perm, &shared_perm);
+ bdrv_check_perm(old_bs, perm, shared_perm, NULL, &error_abort);
+ bdrv_set_perm(old_bs, perm, shared_perm);
+ }
+
+ bdrv_replace_child_noperm(child, new_bs);
+
+ if (new_bs) {
bdrv_get_cumulative_perm(new_bs, &perm, &shared_perm);
if (check_new_perm) {
- bdrv_check_perm(new_bs, perm, shared_perm, &error_abort);
+ bdrv_check_perm(new_bs, perm, shared_perm, NULL, &error_abort);
}
bdrv_set_perm(new_bs, perm, shared_perm);
-
- if (child->role->attach) {
- child->role->attach(child);
- }
}
}
@@ -2891,35 +2912,82 @@ void bdrv_close_all(void)
assert(QTAILQ_EMPTY(&all_bdrv_states));
}
-static void change_parent_backing_link(BlockDriverState *from,
- BlockDriverState *to)
+static bool should_update_child(BdrvChild *c, BlockDriverState *to)
+{
+ BdrvChild *to_c;
+
+ if (c->role->stay_at_node) {
+ 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) {
+ return false;
+ }
+ }
+
+ return true;
+}
+
+void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
+ Error **errp)
{
- BdrvChild *c, *next, *to_c;
+ BdrvChild *c, *next;
+ GSList *list = NULL, *p;
+ uint64_t old_perm, old_shared;
+ uint64_t perm = 0, shared = BLK_PERM_ALL;
+ int ret;
+
+ assert(!atomic_read(&from->in_flight));
+ assert(!atomic_read(&to->in_flight));
+
+ /* Make sure that @from doesn't go away until we have successfully attached
+ * all of its parents to @to. */
+ bdrv_ref(from);
+ /* Put all parents into @list and calculate their cumulative permissions */
QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) {
- if (c->role->stay_at_node) {
+ if (!should_update_child(c, to)) {
continue;
}
- 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) {
- continue;
- }
- }
+ list = g_slist_prepend(list, c);
+ perm |= c->perm;
+ shared &= c->shared_perm;
+ }
+
+ /* 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, perm, shared, list, errp);
+ if (ret < 0) {
+ bdrv_abort_perm_update(to);
+ goto out;
+ }
+
+ /* Now actually perform the change. We performed the permission check for
+ * all elements of @list at once, so set the permissions all at once at the
+ * very end. */
+ for (p = list; p != NULL; p = p->next) {
+ c = p->data;
bdrv_ref(to);
- /* FIXME Are we sure that bdrv_replace_child() can't run into
- * &error_abort because of permissions? */
- bdrv_replace_child(c, to, true);
+ bdrv_replace_child_noperm(c, to);
bdrv_unref(from);
}
+
+ bdrv_get_cumulative_perm(to, &old_perm, &old_shared);
+ bdrv_set_perm(to, old_perm | perm, old_shared | shared);
+
+out:
+ g_slist_free(list);
+ bdrv_unref(from);
}
/*
@@ -2943,16 +3011,18 @@ void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
{
Error *local_err = NULL;
- assert(!atomic_read(&bs_top->in_flight));
- assert(!atomic_read(&bs_new->in_flight));
-
bdrv_set_backing_hd(bs_new, bs_top, &local_err);
if (local_err) {
error_propagate(errp, local_err);
goto out;
}
- change_parent_backing_link(bs_top, bs_new);
+ bdrv_replace_node(bs_top, bs_new, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ bdrv_set_backing_hd(bs_new, NULL, &error_abort);
+ goto out;
+ }
/* bs_new is now referenced by its new parents, we don't need the
* additional reference any more. */
@@ -2960,18 +3030,6 @@ out:
bdrv_unref(bs_new);
}
-void bdrv_replace_in_backing_chain(BlockDriverState *old, BlockDriverState *new)
-{
- assert(!bdrv_requests_pending(old));
- assert(!bdrv_requests_pending(new));
-
- bdrv_ref(old);
-
- change_parent_backing_link(old, new);
-
- bdrv_unref(old);
-}
-
static void bdrv_delete(BlockDriverState *bs)
{
assert(!bs->job);