#include "block/qdict.h"
#include "qemu/error-report.h"
#include "module_block.h"
+#include "qemu/main-loop.h"
#include "qemu/module.h"
#include "qapi/error.h"
#include "qapi/qmp/qdict.h"
#endif
}
-/* if filename is absolute, just copy it to dest. Otherwise, build a
+/* if filename is absolute, just return its duplicate. Otherwise, build a
path to it by considering it is relative to base_path. URL are
supported. */
-void path_combine(char *dest, int dest_size,
- const char *base_path,
- const char *filename)
+char *path_combine(const char *base_path, const char *filename)
{
+ const char *protocol_stripped = NULL;
const char *p, *p1;
+ char *result;
int len;
- if (dest_size <= 0)
- return;
if (path_is_absolute(filename)) {
- pstrcpy(dest, dest_size, filename);
- } else {
- const char *protocol_stripped = NULL;
+ return g_strdup(filename);
+ }
- if (path_has_protocol(base_path)) {
- protocol_stripped = strchr(base_path, ':');
- if (protocol_stripped) {
- protocol_stripped++;
- }
+ if (path_has_protocol(base_path)) {
+ protocol_stripped = strchr(base_path, ':');
+ if (protocol_stripped) {
+ protocol_stripped++;
}
- p = protocol_stripped ?: base_path;
+ }
+ p = protocol_stripped ?: base_path;
- p1 = strrchr(base_path, '/');
+ p1 = strrchr(base_path, '/');
#ifdef _WIN32
- {
- const char *p2;
- p2 = strrchr(base_path, '\\');
- if (!p1 || p2 > p1)
- p1 = p2;
+ {
+ const char *p2;
+ p2 = strrchr(base_path, '\\');
+ if (!p1 || p2 > p1) {
+ p1 = p2;
}
+ }
#endif
- if (p1)
- p1++;
- else
- p1 = base_path;
- if (p1 > p)
- p = p1;
- len = p - base_path;
- if (len > dest_size - 1)
- len = dest_size - 1;
- memcpy(dest, base_path, len);
- dest[len] = '\0';
- pstrcat(dest, dest_size, filename);
+ if (p1) {
+ p1++;
+ } else {
+ p1 = base_path;
+ }
+ if (p1 > p) {
+ p = p1;
}
+ len = p - base_path;
+
+ result = g_malloc(len + strlen(filename) + 1);
+ memcpy(result, base_path, len);
+ strcpy(result + len, filename);
+
+ return result;
}
/*
return -EACCES;
}
-void bdrv_get_full_backing_filename_from_filename(const char *backed,
- const char *backing,
- char *dest, size_t sz,
- Error **errp)
+/*
+ * If @backing is empty, this function returns NULL without setting
+ * @errp. In all other cases, NULL will only be returned with @errp
+ * set.
+ *
+ * Therefore, a return value of NULL without @errp set means that
+ * there is no backing file; if @errp is set, there is one but its
+ * absolute filename cannot be generated.
+ */
+char *bdrv_get_full_backing_filename_from_filename(const char *backed,
+ const char *backing,
+ Error **errp)
{
- if (backing[0] == '\0' || path_has_protocol(backing) ||
- path_is_absolute(backing))
- {
- pstrcpy(dest, sz, backing);
+ if (backing[0] == '\0') {
+ return NULL;
+ } else if (path_has_protocol(backing) || path_is_absolute(backing)) {
+ return g_strdup(backing);
} else if (backed[0] == '\0' || strstart(backed, "json:", NULL)) {
error_setg(errp, "Cannot use relative backing file names for '%s'",
backed);
+ return NULL;
} else {
- path_combine(dest, sz, backed, backing);
+ return path_combine(backed, backing);
}
}
-void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz,
- Error **errp)
+/*
+ * If @filename is empty or NULL, this function returns NULL without
+ * setting @errp. In all other cases, NULL will only be returned with
+ * @errp set.
+ */
+static char *bdrv_make_absolute_filename(BlockDriverState *relative_to,
+ const char *filename, Error **errp)
{
- char *backed;
+ char *dir, *full_name;
- bdrv_refresh_filename(bs);
+ if (!filename || filename[0] == '\0') {
+ return NULL;
+ } else if (path_has_protocol(filename) || path_is_absolute(filename)) {
+ return g_strdup(filename);
+ }
+
+ dir = bdrv_dirname(relative_to, errp);
+ if (!dir) {
+ return NULL;
+ }
+
+ full_name = g_strconcat(dir, filename, NULL);
+ g_free(dir);
+ return full_name;
+}
- backed = bs->exact_filename[0] ? bs->exact_filename : bs->filename;
- bdrv_get_full_backing_filename_from_filename(backed, bs->backing_file,
- dest, sz, errp);
+char *bdrv_get_full_backing_filename(BlockDriverState *bs, Error **errp)
+{
+ return bdrv_make_absolute_filename(bs, bs->backing_file, errp);
}
void bdrv_register(BlockDriver *bdrv)
return bdrv_do_find_format(format_name);
}
-int bdrv_is_whitelisted(BlockDriver *drv, bool read_only)
+static int bdrv_format_is_whitelisted(const char *format_name, bool read_only)
{
static const char *whitelist_rw[] = {
CONFIG_BDRV_RW_WHITELIST
}
for (p = whitelist_rw; *p; p++) {
- if (!strcmp(drv->format_name, *p)) {
+ if (!strcmp(format_name, *p)) {
return 1;
}
}
if (read_only) {
for (p = whitelist_ro; *p; p++) {
- if (!strcmp(drv->format_name, *p)) {
+ if (!strcmp(format_name, *p)) {
return 1;
}
}
return 0;
}
+int bdrv_is_whitelisted(BlockDriver *drv, bool read_only)
+{
+ return bdrv_format_is_whitelisted(drv->format_name, read_only);
+}
+
bool bdrv_uses_whitelist(void)
{
return use_bdrv_whitelist;
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)
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
qdict_set_default_str(child_options, BDRV_OPT_CACHE_DIRECT, "off");
qdict_set_default_str(child_options, BDRV_OPT_CACHE_NO_FLUSH, "on");
- /* Copy the read-only option from the parent */
+ /* Copy the read-only and discard options from the parent */
qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
+ qdict_copy_default(child_options, parent_options, BDRV_OPT_DISCARD);
/* aio=native doesn't work for cache.direct=off, so disable it for the
* temporary snapshot */
.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,
};
/*
.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)
.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)
*/
open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_PROTOCOL);
- /*
- * Snapshots should be writable.
- */
- if (flags & BDRV_O_TEMPORARY) {
- open_flags |= BDRV_O_RDWR;
- }
-
return open_flags;
}
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,
+ uint64_t *shared_perm);
typedef struct BlockReopenQueueEntry {
bool prepared;
+ bool perms_checked;
BDRVReopenState state;
QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry;
} BlockReopenQueueEntry;
uint64_t parent_perm, uint64_t parent_shared,
uint64_t *nperm, uint64_t *nshared)
{
- if (bs->drv && bs->drv->bdrv_child_perm) {
- bs->drv->bdrv_child_perm(bs, c, role, reopen_queue,
- parent_perm, parent_shared,
- nperm, nshared);
- }
+ assert(bs->drv && bs->drv->bdrv_child_perm);
+ bs->drv->bdrv_child_perm(bs, c, role, reopen_queue,
+ parent_perm, parent_shared,
+ nperm, nshared);
/* TODO Take force_share from reopen_queue */
if (child_bs && child_bs->force_share) {
*nshared = BLK_PERM_ALL;
* 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))
{
- 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;
}
/* 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;
}
* 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);
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));
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));
}
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) {
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;
}
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,
uint64_t perm, uint64_t shared,
uint64_t *nperm, uint64_t *nshared)
{
- if (c == NULL) {
- *nperm = perm & DEFAULT_PERM_PASSTHROUGH;
- *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED;
- return;
- }
-
- *nperm = (perm & DEFAULT_PERM_PASSTHROUGH) |
- (c->perm & DEFAULT_PERM_UNCHANGED);
- *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) |
- (c->shared_perm & DEFAULT_PERM_UNCHANGED);
+ *nperm = perm & DEFAULT_PERM_PASSTHROUGH;
+ *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED;
}
void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
BlockDriverState *new_bs)
{
BlockDriverState *old_bs = child->bs;
- int i;
+ int new_bs_quiesce_counter;
+ int drain_saldo;
+
+ assert(!child->frozen);
if (old_bs && new_bs) {
assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs));
}
+
+ new_bs_quiesce_counter = (new_bs ? new_bs->quiesce_counter : 0);
+ drain_saldo = new_bs_quiesce_counter - child->parent_quiesce_counter;
+
+ /*
+ * If the new child node is drained but the old one was not, flush
+ * all outstanding requests to the old child node.
+ */
+ while (drain_saldo > 0 && child->role->drained_begin) {
+ bdrv_parent_drained_begin_single(child, true);
+ drain_saldo--;
+ }
+
if (old_bs) {
/* Detach first so that the recursive drain sections coming from @child
* are already gone and we only end the drain sections that came from
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);
- }
- }
QLIST_REMOVE(child, next_parent);
}
if (new_bs) {
QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent);
- if (new_bs->quiesce_counter && child->role->drained_begin) {
- int num = new_bs->quiesce_counter;
- if (child->role->parent_is_bds) {
- num -= bdrv_drain_all_count;
- }
- assert(num >= 0);
- for (i = 0; i < num; i++) {
- bdrv_parent_drained_begin_single(child, true);
- }
- }
+
+ /*
+ * Detaching the old node may have led to the new node's
+ * quiesce_counter having been decreased. Not a problem, we
+ * just need to recognize this here and then invoke
+ * drained_end appropriately more often.
+ */
+ assert(new_bs->quiesce_counter <= new_bs_quiesce_counter);
+ drain_saldo += new_bs->quiesce_counter - new_bs_quiesce_counter;
/* Attach only after starting new drained sections, so that recursive
* drain sections coming from @child don't get an extra .drained_begin
child->role->attach(child);
}
}
+
+ /*
+ * If the old child node was drained but the new one is not, allow
+ * requests to come in only after the new node has been attached.
+ */
+ while (drain_saldo < 0 && child->role->drained_end) {
+ bdrv_parent_drained_end_single(child);
+ drain_saldo++;
+ }
}
/*
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);
+ }
- if (new_bs) {
- bdrv_get_cumulative_perm(new_bs, &perm, &shared_perm);
- bdrv_set_perm(new_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);
}
}
+/*
+ * This function steals the reference to child_bs from the caller.
+ * That reference is later dropped by bdrv_root_unref_child().
+ *
+ * On failure NULL is returned, errp is set and the reference to
+ * child_bs is also dropped.
+ *
+ * The caller must hold the AioContext lock @child_bs, but not that of @ctx
+ * (unless @child_bs is already in @ctx).
+ */
BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
const char *child_name,
const BdrvChildRole *child_role,
+ AioContext *ctx,
uint64_t perm, uint64_t shared_perm,
void *opaque, Error **errp)
{
BdrvChild *child;
+ 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);
return NULL;
}
.opaque = opaque,
};
+ /* If the AioContexts don't match, first try to move the subtree of
+ * child_bs into the AioContext of the new parent. If this doesn't work,
+ * try moving the parent into the AioContext of child_bs instead. */
+ if (bdrv_get_aio_context(child_bs) != ctx) {
+ ret = bdrv_try_set_aio_context(child_bs, ctx, &local_err);
+ if (ret < 0 && child_role->can_set_aio_ctx) {
+ GSList *ignore = g_slist_prepend(NULL, child);;
+ ctx = bdrv_get_aio_context(child_bs);
+ if (child_role->can_set_aio_ctx(child, ctx, &ignore, NULL)) {
+ error_free(local_err);
+ ret = 0;
+ g_slist_free(ignore);
+ ignore = g_slist_prepend(NULL, child);;
+ child_role->set_aio_ctx(child, ctx, &ignore);
+ }
+ g_slist_free(ignore);
+ }
+ if (ret < 0) {
+ error_propagate(errp, local_err);
+ g_free(child);
+ bdrv_abort_perm_update(child_bs);
+ return NULL;
+ }
+ }
+
/* This performs the matching bdrv_set_perm() for the above check. */
bdrv_replace_child(child, child_bs);
return child;
}
+/*
+ * This function transfers the reference to child_bs from the caller
+ * to parent_bs. That reference is later dropped by parent_bs on
+ * bdrv_close() or if someone calls bdrv_unref_child().
+ *
+ * On failure NULL is returned, errp is set and the reference to
+ * child_bs is also dropped.
+ *
+ * If @parent_bs and @child_bs are in different AioContexts, the caller must
+ * hold the AioContext lock for @child_bs, but not for @parent_bs.
+ */
BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
BlockDriverState *child_bs,
const char *child_name,
bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm);
assert(parent_bs->drv);
- assert(bdrv_get_aio_context(parent_bs) == bdrv_get_aio_context(child_bs));
bdrv_child_perm(parent_bs, child_bs, NULL, child_role, NULL,
perm, shared_perm, &perm, &shared_perm);
child = bdrv_root_attach_child(child_bs, child_name, child_role,
+ bdrv_get_aio_context(parent_bs),
perm, shared_perm, parent_bs, errp);
if (child == NULL) {
return NULL;
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;
}
}
}
+ 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);
}
bool update_inherits_from = bdrv_chain_contains(bs, backing_hd) &&
bdrv_inherits_from_recursive(backing_hd, bs);
+ if (bdrv_is_backing_chain_frozen(bs, backing_bs(bs), errp)) {
+ return;
+ }
+
if (backing_hd) {
bdrv_ref(backing_hd);
}
/* If backing_hd was already part of bs's backing chain, and
* inherits_from pointed recursively to bs then let's update it to
* point directly to bs (else it will become NULL). */
- if (update_inherits_from) {
+ if (bs->backing && update_inherits_from) {
backing_hd->inherits_from = bs;
}
- if (!bs->backing) {
- bdrv_unref(backing_hd);
- }
out:
bdrv_refresh_limits(bs, NULL);
int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
const char *bdref_key, Error **errp)
{
- char *backing_filename = g_malloc0(PATH_MAX);
+ char *backing_filename = NULL;
char *bdref_key_dot;
const char *reference = NULL;
int ret = 0;
+ bool implicit_backing = false;
BlockDriverState *backing_hd;
QDict *options;
QDict *tmp_parent_options = NULL;
*/
reference = qdict_get_try_str(parent_options, bdref_key);
if (reference || qdict_haskey(options, "file.filename")) {
- backing_filename[0] = '\0';
+ /* keep backing_filename NULL */
} else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) {
qobject_unref(options);
goto free_exit;
} else {
- bdrv_get_full_backing_filename(bs, backing_filename, PATH_MAX,
- &local_err);
+ if (qdict_size(options) == 0) {
+ /* If the user specifies options that do not modify the
+ * backing file's behavior, we might still consider it the
+ * implicit backing file. But it's easier this way, and
+ * just specifying some of the backing BDS's options is
+ * only possible with -drive anyway (otherwise the QAPI
+ * schema forces the user to specify everything). */
+ implicit_backing = !strcmp(bs->auto_backing_file, bs->backing_file);
+ }
+
+ backing_filename = bdrv_get_full_backing_filename(bs, &local_err);
if (local_err) {
ret = -EINVAL;
error_propagate(errp, local_err);
qdict_put_str(options, "driver", bs->backing_format);
}
- backing_hd = bdrv_open_inherit(*backing_filename ? backing_filename : NULL,
- reference, options, 0, bs, &child_backing,
- errp);
+ backing_hd = bdrv_open_inherit(backing_filename, reference, options, 0, bs,
+ &child_backing, errp);
if (!backing_hd) {
bs->open_flags |= BDRV_O_NO_BACKING;
error_prepend(errp, "Could not open backing file: ");
ret = -EINVAL;
goto free_exit;
}
- bdrv_set_aio_context(backing_hd, bdrv_get_aio_context(bs));
+
+ if (implicit_backing) {
+ bdrv_refresh_filename(backing_hd);
+ pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file),
+ backing_hd->filename);
+ }
/* Hook up the backing file link; drop our reference, bs owns the
* backing_hd reference now */
const BdrvChildRole *child_role,
bool allow_none, Error **errp)
{
- BdrvChild *c;
BlockDriverState *bs;
bs = bdrv_open_child_bs(filename, options, bdref_key, parent, child_role,
return NULL;
}
- c = bdrv_attach_child(parent, bs, bdref_key, child_role, errp);
- if (!c) {
- bdrv_unref(bs);
- return NULL;
- }
-
- return c;
+ return bdrv_attach_child(parent, bs, bdref_key, child_role, errp);
}
/* TODO Future callers may need to specify parent/child_role in order for
/* Not requesting BLK_PERM_CONSISTENT_READ because we're only
* looking at the header to guess the image format. This works even
* in cases where a guest would not see a consistent state. */
- file = blk_new(0, BLK_PERM_ALL);
+ file = blk_new(bdrv_get_aio_context(file_bs), 0, BLK_PERM_ALL);
blk_insert_bs(file, file_bs, &local_err);
bdrv_unref(file_bs);
if (local_err) {
NULL, errp);
}
+/* Return true if the NULL-terminated @list contains @str */
+static bool is_str_in_list(const char *str, const char *const *list)
+{
+ if (str && list) {
+ int i;
+ for (i = 0; list[i] != NULL; i++) {
+ if (!strcmp(str, list[i])) {
+ return true;
+ }
+ }
+ }
+ return false;
+}
+
+/*
+ * Check that every option set in @bs->options is also set in
+ * @new_opts.
+ *
+ * Options listed in the common_options list and in
+ * @bs->drv->mutable_opts are skipped.
+ *
+ * Return 0 on success, otherwise return -EINVAL and set @errp.
+ */
+static int bdrv_reset_options_allowed(BlockDriverState *bs,
+ const QDict *new_opts, Error **errp)
+{
+ const QDictEntry *e;
+ /* These options are common to all block drivers and are handled
+ * in bdrv_reopen_prepare() so they can be left out of @new_opts */
+ const char *const common_options[] = {
+ "node-name", "discard", "cache.direct", "cache.no-flush",
+ "read-only", "auto-read-only", "detect-zeroes", NULL
+ };
+
+ for (e = qdict_first(bs->options); e; e = qdict_next(bs->options, e)) {
+ if (!qdict_haskey(new_opts, e->key) &&
+ !is_str_in_list(e->key, common_options) &&
+ !is_str_in_list(e->key, bs->drv->mutable_opts)) {
+ error_setg(errp, "Option '%s' cannot be reset "
+ "to its default value", e->key);
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Returns true if @child can be reached recursively from @bs
+ */
+static bool bdrv_recurse_has_child(BlockDriverState *bs,
+ BlockDriverState *child)
+{
+ BdrvChild *c;
+
+ if (bs == child) {
+ return true;
+ }
+
+ QLIST_FOREACH(c, &bs->children, next) {
+ if (bdrv_recurse_has_child(c->bs, child)) {
+ return true;
+ }
+ }
+
+ return false;
+}
+
/*
* Adds a BlockDriverState to a simple queue for an atomic, transactional
* reopen of multiple devices.
QDict *options,
const BdrvChildRole *role,
QDict *parent_options,
- int parent_flags)
+ int parent_flags,
+ bool keep_old_opts)
{
assert(bs != NULL);
*/
/* Old explicitly set values (don't overwrite by inherited value) */
- if (bs_entry) {
- old_options = qdict_clone_shallow(bs_entry->state.explicit_options);
- } else {
- old_options = qdict_clone_shallow(bs->explicit_options);
+ if (bs_entry || keep_old_opts) {
+ old_options = qdict_clone_shallow(bs_entry ?
+ bs_entry->state.explicit_options :
+ bs->explicit_options);
+ bdrv_join_options(bs, options, old_options);
+ qobject_unref(old_options);
}
- bdrv_join_options(bs, options, old_options);
- qobject_unref(old_options);
explicit_options = qdict_clone_shallow(options);
flags = bdrv_get_flags(bs);
}
- /* Old values are used for options that aren't set yet */
- old_options = qdict_clone_shallow(bs->options);
- bdrv_join_options(bs, options, old_options);
- qobject_unref(old_options);
+ if (keep_old_opts) {
+ /* Old values are used for options that aren't set yet */
+ old_options = qdict_clone_shallow(bs->options);
+ bdrv_join_options(bs, options, old_options);
+ qobject_unref(old_options);
+ }
/* We have the final set of options so let's update the flags */
options_copy = qdict_clone_shallow(options);
bs_entry->state.perm = UINT64_MAX;
bs_entry->state.shared_perm = 0;
+ /*
+ * If keep_old_opts is false then it means that unspecified
+ * options must be reset to their original value. We don't allow
+ * resetting 'backing' but we need to know if the option is
+ * missing in order to decide if we have to return an error.
+ */
+ if (!keep_old_opts) {
+ bs_entry->state.backing_missing =
+ !qdict_haskey(options, "backing") &&
+ !qdict_haskey(options, "backing.driver");
+ }
+
QLIST_FOREACH(child, &bs->children, next) {
- QDict *new_child_options;
- char *child_key_dot;
+ QDict *new_child_options = NULL;
+ bool child_keep_old = keep_old_opts;
/* reopen can only change the options of block devices that were
* implicitly created and inherited options. For other (referenced)
continue;
}
- child_key_dot = g_strdup_printf("%s.", child->name);
- qdict_extract_subqdict(explicit_options, NULL, child_key_dot);
- qdict_extract_subqdict(options, &new_child_options, child_key_dot);
- g_free(child_key_dot);
+ /* Check if the options contain a child reference */
+ if (qdict_haskey(options, child->name)) {
+ const char *childref = qdict_get_try_str(options, child->name);
+ /*
+ * The current child must not be reopened if the child
+ * reference is null or points to a different node.
+ */
+ if (g_strcmp0(childref, child->bs->node_name)) {
+ continue;
+ }
+ /*
+ * If the child reference points to the current child then
+ * reopen it with its existing set of options (note that
+ * it can still inherit new options from the parent).
+ */
+ child_keep_old = true;
+ } else {
+ /* Extract child options ("child-name.*") */
+ char *child_key_dot = g_strdup_printf("%s.", child->name);
+ qdict_extract_subqdict(explicit_options, NULL, child_key_dot);
+ qdict_extract_subqdict(options, &new_child_options, child_key_dot);
+ g_free(child_key_dot);
+ }
bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options,
- child->role, options, flags);
+ child->role, options, flags, child_keep_old);
}
return bs_queue;
BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
BlockDriverState *bs,
- QDict *options)
+ QDict *options, bool keep_old_opts)
{
- return bdrv_reopen_queue_child(bs_queue, bs, options, NULL, NULL, 0);
+ return bdrv_reopen_queue_child(bs_queue, bs, options, NULL, NULL, 0,
+ keep_old_opts);
}
/*
* All affected nodes must be drained between bdrv_reopen_queue() and
* bdrv_reopen_multiple().
*/
-int bdrv_reopen_multiple(AioContext *ctx, BlockReopenQueue *bs_queue, Error **errp)
+int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp)
{
int ret = -1;
BlockReopenQueueEntry *bs_entry, *next;
- Error *local_err = NULL;
assert(bs_queue != NULL);
QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
assert(bs_entry->state.bs->quiesce_counter > 0);
- if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, &local_err)) {
- error_propagate(errp, local_err);
+ if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, errp)) {
goto cleanup;
}
bs_entry->prepared = true;
}
+ 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, NULL, errp);
+ if (ret < 0) {
+ goto cleanup_perm;
+ }
+ /* Check if new_backing_bs would accept the new permissions */
+ if (state->replace_backing_bs && state->new_backing_bs) {
+ uint64_t nperm, nshared;
+ bdrv_child_perm(state->bs, state->new_backing_bs,
+ NULL, &child_backing, bs_queue,
+ state->perm, state->shared_perm,
+ &nperm, &nshared);
+ ret = bdrv_check_update_perm(state->new_backing_bs, NULL,
+ nperm, nshared, NULL, NULL, errp);
+ if (ret < 0) {
+ goto cleanup_perm;
+ }
+ }
+ bs_entry->perms_checked = true;
+ }
+
/* If we reach this point, we have success and just need to apply the
* changes
*/
}
ret = 0;
+cleanup_perm:
+ QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) {
+ BDRVReopenState *state = &bs_entry->state;
+
+ if (!bs_entry->perms_checked) {
+ continue;
+ }
+ if (ret == 0) {
+ bdrv_set_perm(state->bs, state->perm, state->shared_perm);
+ } else {
+ bdrv_abort_perm_update(state->bs);
+ if (state->replace_backing_bs && state->new_backing_bs) {
+ bdrv_abort_perm_update(state->new_backing_bs);
+ }
+ }
+ }
cleanup:
QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) {
if (ret) {
qobject_unref(bs_entry->state.explicit_options);
qobject_unref(bs_entry->state.options);
}
+ if (bs_entry->state.new_backing_bs) {
+ bdrv_unref(bs_entry->state.new_backing_bs);
+ }
g_free(bs_entry);
}
g_free(bs_queue);
qdict_put_bool(opts, BDRV_OPT_READ_ONLY, read_only);
bdrv_subtree_drained_begin(bs);
- queue = bdrv_reopen_queue(NULL, bs, opts);
- ret = bdrv_reopen_multiple(bdrv_get_aio_context(bs), queue, errp);
+ queue = bdrv_reopen_queue(NULL, bs, opts, true);
+ ret = bdrv_reopen_multiple(queue, errp);
bdrv_subtree_drained_end(bs);
return ret;
}
/*
- * Prepares a BlockDriverState for reopen. All changes are staged in the
- * 'opaque' field of the BDRVReopenState, which is used and allocated by
- * the block driver layer .bdrv_reopen_prepare()
+ * Take a BDRVReopenState and check if the value of 'backing' in the
+ * reopen_state->options QDict is valid or not.
*
- * bs is the BlockDriverState to reopen
- * flags are the new open flags
+ * If 'backing' is missing from the QDict then return 0.
+ *
+ * If 'backing' contains the node name of the backing file of
+ * reopen_state->bs then return 0.
+ *
+ * If 'backing' contains a different node name (or is null) then check
+ * whether the current backing file can be replaced with the new one.
+ * If that's the case then reopen_state->replace_backing_bs is set to
+ * true and reopen_state->new_backing_bs contains a pointer to the new
+ * backing BlockDriverState (or NULL).
+ *
+ * Return 0 on success, otherwise return < 0 and set @errp.
+ */
+static int bdrv_reopen_parse_backing(BDRVReopenState *reopen_state,
+ Error **errp)
+{
+ BlockDriverState *bs = reopen_state->bs;
+ BlockDriverState *overlay_bs, *new_backing_bs;
+ QObject *value;
+ const char *str;
+
+ value = qdict_get(reopen_state->options, "backing");
+ if (value == NULL) {
+ return 0;
+ }
+
+ switch (qobject_type(value)) {
+ case QTYPE_QNULL:
+ new_backing_bs = NULL;
+ break;
+ case QTYPE_QSTRING:
+ str = qobject_get_try_str(value);
+ new_backing_bs = bdrv_lookup_bs(NULL, str, errp);
+ if (new_backing_bs == NULL) {
+ return -EINVAL;
+ } else if (bdrv_recurse_has_child(new_backing_bs, bs)) {
+ error_setg(errp, "Making '%s' a backing file of '%s' "
+ "would create a cycle", str, bs->node_name);
+ return -EINVAL;
+ }
+ break;
+ default:
+ /* 'backing' does not allow any other data type */
+ g_assert_not_reached();
+ }
+
+ /*
+ * TODO: before removing the x- prefix from x-blockdev-reopen we
+ * should move the new backing file into the right AioContext
+ * instead of returning an error.
+ */
+ if (new_backing_bs) {
+ if (bdrv_get_aio_context(new_backing_bs) != bdrv_get_aio_context(bs)) {
+ error_setg(errp, "Cannot use a new backing file "
+ "with a different AioContext");
+ return -EINVAL;
+ }
+ }
+
+ /*
+ * Find the "actual" backing file by skipping all links that point
+ * to an implicit node, if any (e.g. a commit filter node).
+ */
+ overlay_bs = bs;
+ while (backing_bs(overlay_bs) && backing_bs(overlay_bs)->implicit) {
+ overlay_bs = backing_bs(overlay_bs);
+ }
+
+ /* If we want to replace the backing file we need some extra checks */
+ if (new_backing_bs != backing_bs(overlay_bs)) {
+ /* Check for implicit nodes between bs and its backing file */
+ if (bs != overlay_bs) {
+ error_setg(errp, "Cannot change backing link if '%s' has "
+ "an implicit backing file", bs->node_name);
+ return -EPERM;
+ }
+ /* Check if the backing link that we want to replace is frozen */
+ if (bdrv_is_backing_chain_frozen(overlay_bs, backing_bs(overlay_bs),
+ errp)) {
+ return -EPERM;
+ }
+ reopen_state->replace_backing_bs = true;
+ if (new_backing_bs) {
+ bdrv_ref(new_backing_bs);
+ reopen_state->new_backing_bs = new_backing_bs;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Prepares a BlockDriverState for reopen. All changes are staged in the
+ * 'opaque' field of the BDRVReopenState, which is used and allocated by
+ * the block driver layer .bdrv_reopen_prepare()
+ *
+ * bs is the BlockDriverState to reopen
+ * flags are the new open flags
* queue is the reopen queue
*
* Returns 0 on success, non-zero on error. On error errp will be set
}
if (drv->bdrv_reopen_prepare) {
+ /*
+ * If a driver-specific option is missing, it means that we
+ * should reset it to its default value.
+ * But not all options allow that, so we need to check it first.
+ */
+ ret = bdrv_reset_options_allowed(reopen_state->bs,
+ reopen_state->options, errp);
+ if (ret) {
+ goto error;
+ }
+
ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err);
if (ret) {
if (local_err != NULL) {
drv_prepared = true;
+ /*
+ * We must provide the 'backing' option if the BDS has a backing
+ * file or if the image file has a backing file name as part of
+ * its metadata. Otherwise the 'backing' option can be omitted.
+ */
+ if (drv->supports_backing && reopen_state->backing_missing &&
+ (backing_bs(reopen_state->bs) || reopen_state->bs->backing_file[0])) {
+ error_setg(errp, "backing is missing for '%s'",
+ reopen_state->bs->node_name);
+ ret = -EINVAL;
+ goto error;
+ }
+
+ /*
+ * Allow changing the 'backing' option. The new value can be
+ * either a reference to an existing node (using its node name)
+ * or NULL to simply detach the current backing file.
+ */
+ ret = bdrv_reopen_parse_backing(reopen_state, errp);
+ if (ret < 0) {
+ goto error;
+ }
+ qdict_del(reopen_state->options, "backing");
+
/* Options that are not handled are only okay if they are unchanged
* compared to the old state. It is expected that some options are only
* used for the initial open, but not reopen (e.g. filename) */
} while ((entry = qdict_next(reopen_state->options, entry)));
}
- ret = bdrv_check_perm(reopen_state->bs, queue, reopen_state->perm,
- reopen_state->shared_perm, NULL, errp);
- if (ret < 0) {
- goto error;
- }
-
ret = 0;
/* Restore the original reopen_state->options QDict */
bs->read_only = !(reopen_state->flags & BDRV_O_RDWR);
bs->detect_zeroes = reopen_state->detect_zeroes;
+ if (reopen_state->replace_backing_bs) {
+ qdict_del(bs->explicit_options, "backing");
+ qdict_del(bs->options, "backing");
+ }
+
/* Remove child references from bs->options and bs->explicit_options.
* Child options were already removed in bdrv_reopen_queue_child() */
QLIST_FOREACH(child, &bs->children, next) {
qdict_del(bs->options, child->name);
}
- bdrv_refresh_limits(bs, NULL);
+ /*
+ * Change the backing file if a new one was specified. We do this
+ * after updating bs->options, so bdrv_refresh_filename() (called
+ * from bdrv_set_backing_hd()) has the new values.
+ */
+ if (reopen_state->replace_backing_bs) {
+ BlockDriverState *old_backing_bs = backing_bs(bs);
+ assert(!old_backing_bs || !old_backing_bs->implicit);
+ /* Abort the permission update on the backing bs we're detaching */
+ if (old_backing_bs) {
+ bdrv_abort_perm_update(old_backing_bs);
+ }
+ bdrv_set_backing_hd(bs, reopen_state->new_backing_bs, &error_abort);
+ }
- bdrv_set_perm(reopen_state->bs, reopen_state->perm,
- reopen_state->shared_perm);
+ bdrv_refresh_limits(bs, NULL);
new_can_write =
!bdrv_is_read_only(bs) && !(bdrv_get_flags(bs) & BDRV_O_INACTIVE);
if (drv->bdrv_reopen_abort) {
drv->bdrv_reopen_abort(reopen_state);
}
-
- bdrv_abort_perm_update(reopen_state->bs);
}
BdrvAioNotifier *ban, *ban_next;
BdrvChild *child, *next;
- assert(!bs->job);
assert(!bs->refcnt);
bdrv_drained_begin(bs); /* complete I/O */
bs->drv = NULL;
}
- bdrv_set_backing_hd(bs, NULL, &error_abort);
-
- if (bs->file != NULL) {
- bdrv_unref_child(bs, bs->file);
- bs->file = NULL;
- }
-
QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
- /* TODO Remove bdrv_unref() from drivers' close function and use
- * bdrv_unref_child() here */
- if (child->bs->inherits_from == bs) {
- child->bs->inherits_from = NULL;
- }
- bdrv_detach_child(child);
+ bdrv_unref_child(bs, child);
}
+ bs->backing = NULL;
+ bs->file = NULL;
g_free(bs->opaque);
bs->opaque = NULL;
atomic_set(&bs->copy_on_read, 0);
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);
+ assert(qemu_get_current_aio_context() == qemu_get_aio_context());
+ bdrv_drained_begin(from);
+
/* 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;
}
+ if (c->frozen) {
+ error_setg(errp, "Cannot change '%s' link to '%s'",
+ c->name, from->node_name);
+ goto out;
+ }
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, 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;
out:
g_slist_free(list);
+ bdrv_drained_end(from);
bdrv_unref(from);
}
static void bdrv_delete(BlockDriverState *bs)
{
- assert(!bs->job);
assert(bdrv_op_blocker_is_empty(bs));
assert(!bs->refcnt);
- bdrv_close(bs);
-
/* remove from list, if necessary */
if (bs->node_name[0] != '\0') {
QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list);
}
QTAILQ_REMOVE(&all_bdrv_states, bs, bs_list);
+ bdrv_close(bs);
+
g_free(bs);
}
int ret;
} CheckCo;
-static void bdrv_check_co_entry(void *opaque)
+static void coroutine_fn bdrv_check_co_entry(void *opaque)
{
CheckCo *cco = opaque;
cco->ret = bdrv_co_check(cco->bs, cco->res, cco->fix);
if (ret == 0) {
pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
+ pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file),
+ backing_file ?: "");
}
return ret;
}
return bdrv_find_overlay(bs, NULL);
}
+/*
+ * Return true if at least one of the backing links between @bs and
+ * @base is frozen. @errp is set if that's the case.
+ * @base must be reachable from @bs, or NULL.
+ */
+bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base,
+ Error **errp)
+{
+ BlockDriverState *i;
+
+ for (i = bs; i != base; i = backing_bs(i)) {
+ if (i->backing && i->backing->frozen) {
+ error_setg(errp, "Cannot change '%s' link from '%s' to '%s'",
+ i->backing->name, i->node_name,
+ backing_bs(i)->node_name);
+ return true;
+ }
+ }
+
+ return false;
+}
+
+/*
+ * Freeze all backing links between @bs and @base.
+ * If any of the links is already frozen the operation is aborted and
+ * none of the links are modified.
+ * @base must be reachable from @bs, or NULL.
+ * Returns 0 on success. On failure returns < 0 and sets @errp.
+ */
+int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base,
+ Error **errp)
+{
+ BlockDriverState *i;
+
+ if (bdrv_is_backing_chain_frozen(bs, base, errp)) {
+ 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;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Unfreeze all backing links between @bs and @base. The caller must
+ * ensure that all links are frozen before using this function.
+ * @base must be reachable from @bs, or NULL.
+ */
+void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base)
+{
+ BlockDriverState *i;
+
+ for (i = bs; i != base; i = backing_bs(i)) {
+ if (i->backing) {
+ assert(i->backing->frozen);
+ i->backing->frozen = false;
+ }
+ }
+}
+
/*
* Drops images above 'base' up to and including 'top', and sets the image
* above 'top' to have base as its backing file.
int ret = -EIO;
bdrv_ref(top);
+ bdrv_subtree_drained_begin(top);
if (!top->drv || !base->drv) {
goto exit;
goto exit;
}
+ /* This function changes all links that point to top and makes
+ * them point to base. Check that none of them is frozen. */
+ QLIST_FOREACH(c, &top->parents, next_parent) {
+ if (c->frozen) {
+ goto exit;
+ }
+ }
+
/* If 'base' recursively inherits from 'top' then we should set
* base->inherits_from to top->inherits_from after 'top' and all
* other intermediate nodes have been dropped.
QLIST_FOREACH_SAFE(c, &top->parents, next_parent, next) {
/* Check whether we are allowed to switch c from top to base */
GSList *ignore_children = g_slist_prepend(NULL, c);
- bdrv_check_update_perm(base, NULL, c->perm, c->shared_perm,
- ignore_children, &local_err);
+ ret = bdrv_check_update_perm(base, NULL, c->perm, c->shared_perm,
+ ignore_children, NULL, &local_err);
g_slist_free(ignore_children);
- if (local_err) {
- ret = -EPERM;
+ if (ret < 0) {
error_report_err(local_err);
goto exit;
}
ret = 0;
exit:
+ bdrv_subtree_drained_end(top);
bdrv_unref(top);
return ret;
}
}
void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
- void *opaque)
+ void *opaque, bool read_only)
{
BlockDriver *drv;
int count = 0;
if (drv->format_name) {
bool found = false;
int i = count;
+
+ if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, read_only)) {
+ continue;
+ }
+
while (formats && i && !found) {
found = !strcmp(formats[--i], drv->format_name);
}
bool found = false;
int j = count;
+ if (use_bdrv_whitelist &&
+ !bdrv_format_is_whitelisted(format_name, read_only)) {
+ continue;
+ }
+
while (formats && j && !found) {
found = !strcmp(formats[--j], format_name);
}
int is_protocol = 0;
BlockDriverState *curr_bs = NULL;
BlockDriverState *retval = NULL;
- Error *local_error = NULL;
if (!bs || !bs->drv || !backing_file) {
return NULL;
filename_full = g_malloc(PATH_MAX);
backing_file_full = g_malloc(PATH_MAX);
- filename_tmp = g_malloc(PATH_MAX);
is_protocol = path_has_protocol(backing_file);
- /* This will recursively refresh everything in the backing chain */
- bdrv_refresh_filename(bs);
-
for (curr_bs = bs; curr_bs->backing; curr_bs = curr_bs->backing->bs) {
/* If either of the filename paths is actually a protocol, then
* compare unmodified paths; otherwise make paths relative */
if (is_protocol || path_has_protocol(curr_bs->backing_file)) {
+ char *backing_file_full_ret;
+
if (strcmp(backing_file, curr_bs->backing_file) == 0) {
retval = curr_bs->backing->bs;
break;
}
/* Also check against the full backing filename for the image */
- bdrv_get_full_backing_filename(curr_bs, backing_file_full, PATH_MAX,
- &local_error);
- if (local_error == NULL) {
- if (strcmp(backing_file, backing_file_full) == 0) {
+ backing_file_full_ret = bdrv_get_full_backing_filename(curr_bs,
+ NULL);
+ if (backing_file_full_ret) {
+ bool equal = strcmp(backing_file, backing_file_full_ret) == 0;
+ g_free(backing_file_full_ret);
+ if (equal) {
retval = curr_bs->backing->bs;
break;
}
- } else {
- error_free(local_error);
- local_error = NULL;
}
} else {
/* If not an absolute filename path, make it relative to the current
* image's filename path */
- path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
- backing_file);
-
- /* We are going to compare absolute pathnames */
- if (!realpath(filename_tmp, filename_full)) {
+ filename_tmp = bdrv_make_absolute_filename(curr_bs, backing_file,
+ NULL);
+ /* We are going to compare canonicalized absolute pathnames */
+ if (!filename_tmp || !realpath(filename_tmp, filename_full)) {
+ g_free(filename_tmp);
continue;
}
+ g_free(filename_tmp);
/* We need to make sure the backing filename we are comparing against
* is relative to the current image filename (or absolute) */
- path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
- curr_bs->backing_file);
-
- if (!realpath(filename_tmp, backing_file_full)) {
+ filename_tmp = bdrv_get_full_backing_filename(curr_bs, NULL);
+ if (!filename_tmp || !realpath(filename_tmp, backing_file_full)) {
+ g_free(filename_tmp);
continue;
}
+ g_free(filename_tmp);
if (strcmp(backing_file_full, filename_full) == 0) {
retval = curr_bs->backing->bs;
g_free(filename_full);
g_free(backing_file_full);
- g_free(filename_tmp);
return retval;
}
*/
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);
for (bm = bdrv_dirty_bitmap_next(bs, NULL); bm;
bm = bdrv_dirty_bitmap_next(bs, bm))
{
- bdrv_dirty_bitmap_set_migration(bm, false);
+ bdrv_dirty_bitmap_skip_store(bm, false);
}
ret = refresh_total_sectors(bs, bs->total_sectors);
static int bdrv_inactivate_recurse(BlockDriverState *bs)
{
BdrvChild *child, *parent;
+ bool tighten_restrictions;
uint64_t perm, shared_perm;
int ret;
/* 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 */
size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, img_size);
if (backing_file && !(flags & BDRV_O_NO_BACKING)) {
BlockDriverState *bs;
- char *full_backing = g_new0(char, PATH_MAX);
+ char *full_backing;
int back_flags;
QDict *backing_options = NULL;
- bdrv_get_full_backing_filename_from_filename(filename, backing_file,
- full_backing, PATH_MAX,
- &local_err);
+ full_backing =
+ bdrv_get_full_backing_filename_from_filename(filename, backing_file,
+ &local_err);
if (local_err) {
- g_free(full_backing);
goto out;
}
+ assert(full_backing);
/* backing files always opened read-only */
back_flags = flags;
g_free(ban);
}
-void bdrv_detach_aio_context(BlockDriverState *bs)
+static void bdrv_detach_aio_context(BlockDriverState *bs)
{
BdrvAioNotifier *baf, *baf_tmp;
- BdrvChild *child;
-
- if (!bs->drv) {
- return;
- }
assert(!bs->walking_aio_notifiers);
bs->walking_aio_notifiers = true;
*/
bs->walking_aio_notifiers = false;
- if (bs->drv->bdrv_detach_aio_context) {
+ 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);
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->drv) {
- return;
- }
if (bs->quiesce_counter) {
aio_disable_external(new_context);
bs->aio_context = new_context;
- QLIST_FOREACH(child, &bs->children, next) {
- bdrv_attach_aio_context(child->bs, new_context);
- }
- if (bs->drv->bdrv_attach_aio_context) {
+ if (bs->drv && bs->drv->bdrv_attach_aio_context) {
bs->drv->bdrv_attach_aio_context(bs, new_context);
}
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)
+/*
+ * 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).
+ *
+ * @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)
{
- if (bdrv_get_aio_context(bs) == new_context) {
+ AioContext *old_context = bdrv_get_aio_context(bs);
+ BdrvChild *child;
+
+ g_assert(qemu_get_current_aio_context() == qemu_get_aio_context());
+
+ if (old_context == 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;
+ }
+ assert(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
- * 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,
+ 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,
return to_replace_bs;
}
-static bool append_open_options(QDict *d, BlockDriverState *bs)
+/**
+ * Iterates through the list of runtime option keys that are said to
+ * be "strong" for a BDS. An option is called "strong" if it changes
+ * a BDS's data. For example, the null block driver's "size" and
+ * "read-zeroes" options are strong, but its "latency-ns" option is
+ * not.
+ *
+ * If a key returned by this function ends with a dot, all options
+ * starting with that prefix are strong.
+ */
+static const char *const *strong_options(BlockDriverState *bs,
+ const char *const *curopt)
+{
+ static const char *const global_options[] = {
+ "driver", "filename", NULL
+ };
+
+ if (!curopt) {
+ return &global_options[0];
+ }
+
+ curopt++;
+ if (curopt == &global_options[ARRAY_SIZE(global_options) - 1] && bs->drv) {
+ curopt = bs->drv->strong_runtime_opts;
+ }
+
+ return (curopt && *curopt) ? curopt : NULL;
+}
+
+/**
+ * Copies all strong runtime options from bs->options to the given
+ * QDict. The set of strong option keys is determined by invoking
+ * strong_options().
+ *
+ * Returns true iff any strong option was present in bs->options (and
+ * thus copied to the target QDict) with the exception of "filename"
+ * and "driver". The caller is expected to use this value to decide
+ * whether the existence of strong options prevents the generation of
+ * a plain filename.
+ */
+static bool append_strong_runtime_options(QDict *d, BlockDriverState *bs)
{
- const QDictEntry *entry;
- QemuOptDesc *desc;
bool found_any = false;
+ const char *const *option_name = NULL;
- for (entry = qdict_first(bs->options); entry;
- entry = qdict_next(bs->options, entry))
- {
- /* Exclude all non-driver-specific options */
- for (desc = bdrv_runtime_opts.desc; desc->name; desc++) {
- if (!strcmp(qdict_entry_key(entry), desc->name)) {
- break;
+ if (!bs->drv) {
+ return false;
+ }
+
+ while ((option_name = strong_options(bs, option_name))) {
+ bool option_given = false;
+
+ assert(strlen(*option_name) > 0);
+ if ((*option_name)[strlen(*option_name) - 1] != '.') {
+ QObject *entry = qdict_get(bs->options, *option_name);
+ if (!entry) {
+ continue;
+ }
+
+ qdict_put_obj(d, *option_name, qobject_ref(entry));
+ option_given = true;
+ } else {
+ const QDictEntry *entry;
+ for (entry = qdict_first(bs->options); entry;
+ entry = qdict_next(bs->options, entry))
+ {
+ if (strstart(qdict_entry_key(entry), *option_name, NULL)) {
+ qdict_put_obj(d, qdict_entry_key(entry),
+ qobject_ref(qdict_entry_value(entry)));
+ option_given = true;
+ }
}
}
- if (desc->name) {
- continue;
+
+ /* While "driver" and "filename" need to be included in a JSON filename,
+ * their existence does not prohibit generation of a plain filename. */
+ if (!found_any && option_given &&
+ strcmp(*option_name, "driver") && strcmp(*option_name, "filename"))
+ {
+ found_any = true;
}
+ }
- qdict_put_obj(d, qdict_entry_key(entry),
- qobject_ref(qdict_entry_value(entry)));
- found_any = true;
+ if (!qdict_haskey(d, "driver")) {
+ /* Drivers created with bdrv_new_open_driver() may not have a
+ * @driver option. Add it here. */
+ qdict_put_str(d, "driver", bs->drv->format_name);
}
return found_any;
}
+/* Note: This function may return false positives; it may return true
+ * even if opening the backing file specified by bs's image header
+ * would result in exactly bs->backing. */
+static bool bdrv_backing_overridden(BlockDriverState *bs)
+{
+ if (bs->backing) {
+ return strcmp(bs->auto_backing_file,
+ bs->backing->bs->filename);
+ } else {
+ /* No backing BDS, so if the image header reports any backing
+ * file, it must have been suppressed */
+ return bs->auto_backing_file[0] != '\0';
+ }
+}
+
/* Updates the following BDS fields:
* - exact_filename: A filename which may be used for opening a block device
* which (mostly) equals the given BDS (even without any
BlockDriver *drv = bs->drv;
BdrvChild *child;
QDict *opts;
+ bool backing_overridden;
+ bool generate_json_filename; /* Whether our default implementation should
+ fill exact_filename (false) or not (true) */
if (!drv) {
return;
return;
}
+ backing_overridden = bdrv_backing_overridden(bs);
+
+ if (bs->open_flags & BDRV_O_NO_IO) {
+ /* Without I/O, the backing file does not change anything.
+ * Therefore, in such a case (primarily qemu-img), we can
+ * pretend the backing file has not been overridden even if
+ * it technically has been. */
+ backing_overridden = false;
+ }
+
+ /* Gather the options QDict */
+ opts = qdict_new();
+ generate_json_filename = append_strong_runtime_options(opts, bs);
+ generate_json_filename |= backing_overridden;
+
+ if (drv->bdrv_gather_child_options) {
+ /* Some block drivers may not want to present all of their children's
+ * options, or name them differently from BdrvChild.name */
+ drv->bdrv_gather_child_options(bs, opts, backing_overridden);
+ } else {
+ QLIST_FOREACH(child, &bs->children, next) {
+ if (child->role == &child_backing && !backing_overridden) {
+ /* We can skip the backing BDS if it has not been overridden */
+ continue;
+ }
+
+ qdict_put(opts, child->name,
+ qobject_ref(child->bs->full_open_options));
+ }
+
+ if (backing_overridden && !bs->backing) {
+ /* Force no backing file */
+ qdict_put_null(opts, "backing");
+ }
+ }
+
+ qobject_unref(bs->full_open_options);
+ bs->full_open_options = opts;
+
if (drv->bdrv_refresh_filename) {
/* Obsolete information is of no use here, so drop the old file name
* information before refreshing it */
bs->exact_filename[0] = '\0';
- if (bs->full_open_options) {
- qobject_unref(bs->full_open_options);
- bs->full_open_options = NULL;
- }
- opts = qdict_new();
- append_open_options(opts, bs);
- drv->bdrv_refresh_filename(bs, opts);
- qobject_unref(opts);
+ drv->bdrv_refresh_filename(bs);
} else if (bs->file) {
/* Try to reconstruct valid information from the underlying file */
- bool has_open_options;
bs->exact_filename[0] = '\0';
- if (bs->full_open_options) {
- qobject_unref(bs->full_open_options);
- bs->full_open_options = NULL;
- }
- opts = qdict_new();
- has_open_options = append_open_options(opts, bs);
-
- /* If no specific options have been given for this BDS, the filename of
- * the underlying file should suffice for this one as well */
- if (bs->file->bs->exact_filename[0] && !has_open_options) {
+ /*
+ * We can use the underlying file's filename if:
+ * - it has a filename,
+ * - the file is a protocol BDS, and
+ * - opening that file (as this BDS's format) will automatically create
+ * the BDS tree we have right now, that is:
+ * - the user did not significantly change this BDS's behavior with
+ * some explicit (strong) options
+ * - no non-file child of this BDS has been overridden by the user
+ * Both of these conditions are represented by generate_json_filename.
+ */
+ if (bs->file->bs->exact_filename[0] &&
+ bs->file->bs->drv->bdrv_file_open &&
+ !generate_json_filename)
+ {
strcpy(bs->exact_filename, bs->file->bs->exact_filename);
}
- /* Reconstructing the full options QDict is simple for most format block
- * drivers, as long as the full options are known for the underlying
- * file BDS. The full options QDict of that file BDS should somehow
- * contain a representation of the filename, therefore the following
- * suffices without querying the (exact_)filename of this BDS. */
- if (bs->file->bs->full_open_options) {
- qdict_put_str(opts, "driver", drv->format_name);
- qdict_put(opts, "file",
- qobject_ref(bs->file->bs->full_open_options));
-
- bs->full_open_options = opts;
- } else {
- qobject_unref(opts);
- }
- } else if (!bs->full_open_options && qdict_size(bs->options)) {
- /* There is no underlying file BDS (at least referenced by BDS.file),
- * so the full options QDict should be equal to the options given
- * specifically for this block device when it was opened (plus the
- * driver specification).
- * Because those options don't change, there is no need to update
- * full_open_options when it's already set. */
-
- opts = qdict_new();
- append_open_options(opts, bs);
- qdict_put_str(opts, "driver", drv->format_name);
-
- if (bs->exact_filename[0]) {
- /* This may not work for all block protocol drivers (some may
- * require this filename to be parsed), but we have to find some
- * default solution here, so just include it. If some block driver
- * does not support pure options without any filename at all or
- * needs some special format of the options QDict, it needs to
- * implement the driver-specific bdrv_refresh_filename() function.
- */
- qdict_put_str(opts, "filename", bs->exact_filename);
- }
-
- bs->full_open_options = opts;
}
if (bs->exact_filename[0]) {
pstrcpy(bs->filename, sizeof(bs->filename), bs->exact_filename);
- } else if (bs->full_open_options) {
+ } else {
QString *json = qobject_to_json(QOBJECT(bs->full_open_options));
snprintf(bs->filename, sizeof(bs->filename), "json:%s",
qstring_get_str(json));
}
}
+char *bdrv_dirname(BlockDriverState *bs, Error **errp)
+{
+ BlockDriver *drv = bs->drv;
+
+ if (!drv) {
+ error_setg(errp, "Node '%s' is ejected", bs->node_name);
+ return NULL;
+ }
+
+ if (drv->bdrv_dirname) {
+ return drv->bdrv_dirname(bs, errp);
+ }
+
+ if (bs->file) {
+ return bdrv_dirname(bs->file->bs, errp);
+ }
+
+ bdrv_refresh_filename(bs);
+ if (bs->exact_filename[0] != '\0') {
+ return path_combine(bs->exact_filename, "");
+ }
+
+ error_setg(errp, "Cannot generate a base directory for %s nodes",
+ drv->format_name);
+ return NULL;
+}
+
/*
* Hot add/remove a BDS's child. So the user can take a child offline when
* it is broken and take a new child online
projects / qemu.git / blobdiff