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block: Introduce bdrv_open_child()
It is the same as bdrv_open_image(), except that it doesn't only return success or failure, but the newly created BdrvChild object for the new child node. As the BdrvChild object already contains a BlockDriverState pointer (and this is supposed to become the only pointer so that bdrv_append() and friends can just change a single pointer in BdrvChild), the pbs parameter is removed for bdrv_open_child(). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
parent
df58179267
commit
b4b059f628
63
block.c
63
block.c
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@ -1102,7 +1102,7 @@ static int bdrv_fill_options(QDict **options, const char **pfilename,
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return 0;
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}
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static void bdrv_attach_child(BlockDriverState *parent_bs,
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static BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
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BlockDriverState *child_bs,
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const BdrvChildRole *child_role)
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{
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@ -1113,6 +1113,8 @@ static void bdrv_attach_child(BlockDriverState *parent_bs,
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};
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QLIST_INSERT_HEAD(&parent_bs->children, child, next);
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return child;
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}
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void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd)
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@ -1229,7 +1231,7 @@ free_exit:
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* device's options.
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*
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* If allow_none is true, no image will be opened if filename is false and no
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* BlockdevRef is given. *pbs will remain unchanged and 0 will be returned.
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* BlockdevRef is given. NULL will be returned, but errp remains unset.
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*
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* bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
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* That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
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@ -1237,21 +1239,20 @@ free_exit:
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* BlockdevRef.
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*
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* The BlockdevRef will be removed from the options QDict.
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*
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* To conform with the behavior of bdrv_open(), *pbs has to be NULL.
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*/
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int bdrv_open_image(BlockDriverState **pbs, const char *filename,
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BdrvChild *bdrv_open_child(const char *filename,
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QDict *options, const char *bdref_key,
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BlockDriverState* parent, const BdrvChildRole *child_role,
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BlockDriverState* parent,
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const BdrvChildRole *child_role,
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bool allow_none, Error **errp)
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{
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BdrvChild *c = NULL;
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BlockDriverState *bs;
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QDict *image_options;
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int ret;
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char *bdref_key_dot;
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const char *reference;
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assert(pbs);
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assert(*pbs == NULL);
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assert(child_role != NULL);
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bdref_key_dot = g_strdup_printf("%s.", bdref_key);
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@ -1260,28 +1261,60 @@ int bdrv_open_image(BlockDriverState **pbs, const char *filename,
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reference = qdict_get_try_str(options, bdref_key);
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if (!filename && !reference && !qdict_size(image_options)) {
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if (allow_none) {
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ret = 0;
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} else {
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if (!allow_none) {
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error_setg(errp, "A block device must be specified for \"%s\"",
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bdref_key);
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ret = -EINVAL;
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}
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QDECREF(image_options);
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goto done;
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}
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ret = bdrv_open_inherit(pbs, filename, reference, image_options, 0,
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bs = NULL;
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ret = bdrv_open_inherit(&bs, filename, reference, image_options, 0,
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parent, child_role, NULL, errp);
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if (ret < 0) {
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goto done;
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}
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bdrv_attach_child(parent, *pbs, child_role);
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c = bdrv_attach_child(parent, bs, child_role);
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done:
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qdict_del(options, bdref_key);
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return ret;
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return c;
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}
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/*
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* This is a version of bdrv_open_child() that returns 0/-EINVAL instead of
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* a BdrvChild object.
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*
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* If allow_none is true, no image will be opened if filename is false and no
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* BlockdevRef is given. *pbs will remain unchanged and 0 will be returned.
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*
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* To conform with the behavior of bdrv_open(), *pbs has to be NULL.
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*/
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int bdrv_open_image(BlockDriverState **pbs, const char *filename,
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QDict *options, const char *bdref_key,
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BlockDriverState* parent, const BdrvChildRole *child_role,
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bool allow_none, Error **errp)
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{
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Error *local_err = NULL;
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BdrvChild *c;
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assert(pbs);
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assert(*pbs == NULL);
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c = bdrv_open_child(filename, options, bdref_key, parent, child_role,
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allow_none, &local_err);
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if (local_err) {
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error_propagate(errp, local_err);
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return -EINVAL;
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}
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if (c != NULL) {
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*pbs = c->bs;
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}
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return 0;
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}
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int bdrv_append_temp_snapshot(BlockDriverState *bs, int flags, Error **errp)
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@ -12,6 +12,7 @@
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/* block.c */
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typedef struct BlockDriver BlockDriver;
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typedef struct BlockJob BlockJob;
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typedef struct BdrvChild BdrvChild;
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typedef struct BdrvChildRole BdrvChildRole;
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typedef struct BlockDriverInfo {
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@ -208,6 +209,11 @@ int bdrv_open_image(BlockDriverState **pbs, const char *filename,
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QDict *options, const char *bdref_key,
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BlockDriverState* parent, const BdrvChildRole *child_role,
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bool allow_none, Error **errp);
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BdrvChild *bdrv_open_child(const char *filename,
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QDict *options, const char *bdref_key,
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BlockDriverState* parent,
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const BdrvChildRole *child_role,
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bool allow_none, Error **errp);
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void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd);
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int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp);
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int bdrv_append_temp_snapshot(BlockDriverState *bs, int flags, Error **errp);
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@ -335,11 +335,11 @@ struct BdrvChildRole {
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extern const BdrvChildRole child_file;
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extern const BdrvChildRole child_format;
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typedef struct BdrvChild {
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struct BdrvChild {
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BlockDriverState *bs;
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const BdrvChildRole *role;
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QLIST_ENTRY(BdrvChild) next;
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} BdrvChild;
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};
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/*
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* Note: the function bdrv_append() copies and swaps contents of
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