* Set the current 'total_sectors' value
* Return 0 on success, -errno on error.
*/
-static int refresh_total_sectors(BlockDriverState *bs, int64_t hint)
+int refresh_total_sectors(BlockDriverState *bs, int64_t hint)
{
BlockDriver *drv = bs->drv;
goto out;
}
+ /* Make sure that the node name isn't truncated */
+ if (strlen(node_name) >= sizeof(bs->node_name)) {
+ error_setg(errp, "Node name too long");
+ goto out;
+ }
+
/* copy node name into the bs and insert it into the graph list */
pstrcpy(bs->node_name, sizeof(bs->node_name), node_name);
QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list);
return 0;
}
-#define DEFAULT_PERM_PASSTHROUGH (BLK_PERM_CONSISTENT_READ \
- | BLK_PERM_WRITE \
- | BLK_PERM_WRITE_UNCHANGED \
- | BLK_PERM_RESIZE)
-#define DEFAULT_PERM_UNCHANGED (BLK_PERM_ALL & ~DEFAULT_PERM_PASSTHROUGH)
-
void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
const BdrvChildRole *role,
BlockReopenQueue *reopen_queue,
}
assert(num >= 0);
for (i = 0; i < num; i++) {
- child->role->drained_begin(child);
+ bdrv_parent_drained_begin_single(child, true);
}
}
}
}
-static void bdrv_parent_cb_resize(BlockDriverState *bs)
-{
- BdrvChild *c;
- QLIST_FOREACH(c, &bs->parents, next_parent) {
- if (c->role->resize) {
- c->role->resize(c);
- }
- }
-}
-
/*
* Sets the backing file link of a BDS. A new reference is created; callers
* which don't need their own reference any more must call bdrv_unref().
*
* Reopens all BDS specified in the queue, with the appropriate
* flags. All devices are prepared for reopen, and failure of any
- * device will cause all device changes to be abandonded, and intermediate
+ * device will cause all device changes to be abandoned, and intermediate
* data cleaned up.
*
* If all devices prepare successfully, then the changes are committed
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;
}
}
/* 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;
}
return ret;
}
-/**
- * Truncate file to 'offset' bytes (needed only for file protocols)
- */
-int bdrv_truncate(BdrvChild *child, int64_t offset, PreallocMode prealloc,
- Error **errp)
-{
- BlockDriverState *bs = child->bs;
- BlockDriver *drv = bs->drv;
- int ret;
-
- assert(child->perm & BLK_PERM_RESIZE);
-
- /* if bs->drv == NULL, bs is closed, so there's nothing to do here */
- if (!drv) {
- error_setg(errp, "No medium inserted");
- return -ENOMEDIUM;
- }
- if (offset < 0) {
- error_setg(errp, "Image size cannot be negative");
- return -EINVAL;
- }
-
- if (!drv->bdrv_truncate) {
- if (bs->file && drv->is_filter) {
- return bdrv_truncate(bs->file, offset, prealloc, errp);
- }
- error_setg(errp, "Image format driver does not support resize");
- return -ENOTSUP;
- }
- if (bs->read_only) {
- error_setg(errp, "Image is read-only");
- return -EACCES;
- }
-
- assert(!(bs->open_flags & BDRV_O_INACTIVE));
-
- ret = drv->bdrv_truncate(bs, offset, prealloc, errp);
- if (ret < 0) {
- return ret;
- }
- ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
- if (ret < 0) {
- error_setg_errno(errp, -ret, "Could not refresh total sector count");
- } else {
- offset = bs->total_sectors * BDRV_SECTOR_SIZE;
- }
- bdrv_dirty_bitmap_truncate(bs, offset);
- bdrv_parent_cb_resize(bs);
- atomic_inc(&bs->write_gen);
- return ret;
-}
-
/**
* Length of a allocated file in bytes. Sparse files are counted by actual
* allocated space. Return < 0 if error or unknown.
projects / mirror_qemu.git / blobdiff