X-Git-Url: https://git.proxmox.com/?a=blobdiff_plain;f=block.c;h=0a93ee9ac84c590ab8cd399a7d60c19d11c8a69b;hb=e0a59749efc246646bb208e553489b894450cbcd;hp=4f5ff2cc1208fc2dd022c2487e59df6e7a3eb261;hpb=e6d79c41c961bcdacb60b46c88009b33841f90a7;p=mirror_qemu.git diff --git a/block.c b/block.c index 4f5ff2cc12..0a93ee9ac8 100644 --- a/block.c +++ b/block.c @@ -152,53 +152,53 @@ int path_is_absolute(const char *path) #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; } /* @@ -303,30 +303,61 @@ fail: 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 = bs->exact_filename[0] ? bs->exact_filename : bs->filename; + char *dir, *full_name; + + 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; + } - bdrv_get_full_backing_filename_from_filename(backed, bs->backing_file, - dest, sz, errp); + full_name = g_strconcat(dir, filename, NULL); + g_free(dir); + return full_name; +} + +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) @@ -395,7 +426,7 @@ BlockDriver *bdrv_find_format(const char *format_name) 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 @@ -410,13 +441,13 @@ int bdrv_is_whitelisted(BlockDriver *drv, bool read_only) } 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; } } @@ -424,6 +455,11 @@ int bdrv_is_whitelisted(BlockDriver *drv, bool read_only) 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; @@ -1004,6 +1040,8 @@ static void bdrv_backing_attach(BdrvChild *c) "node is used as backing hd of '%s'", bdrv_get_device_or_node_name(parent)); + bdrv_refresh_filename(backing_hd); + parent->open_flags &= ~BDRV_O_NO_BACKING; pstrcpy(parent->backing_file, sizeof(parent->backing_file), backing_hd->filename); @@ -1125,13 +1163,6 @@ 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; } @@ -1413,6 +1444,7 @@ static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file, } if (file != NULL) { + bdrv_refresh_filename(blk_bs(file)); filename = blk_bs(file)->filename; } else { /* @@ -1438,13 +1470,19 @@ static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file, bs->read_only = !(bs->open_flags & BDRV_O_RDWR); if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) { - error_setg(errp, - !bs->read_only && bdrv_is_whitelisted(drv, true) - ? "Driver '%s' can only be used for read-only devices" - : "Driver '%s' is not whitelisted", - drv->format_name); - ret = -ENOTSUP; - goto fail_opts; + if (!bs->read_only && bdrv_is_whitelisted(drv, true)) { + ret = bdrv_apply_auto_read_only(bs, NULL, NULL); + } else { + ret = -ENOTSUP; + } + if (ret < 0) { + error_setg(errp, + !bs->read_only && bdrv_is_whitelisted(drv, true) + ? "Driver '%s' can only be used for read-only devices" + : "Driver '%s' is not whitelisted", + drv->format_name); + goto fail_opts; + } } /* bdrv_new() and bdrv_close() make it so */ @@ -1653,6 +1691,7 @@ static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared); typedef struct BlockReopenQueueEntry { bool prepared; + bool perms_checked; BDRVReopenState state; QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry; } BlockReopenQueueEntry; @@ -1948,13 +1987,32 @@ static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q, ret = bdrv_check_update_perm(c->bs, q, perm, shared, ignore_children, errp); g_slist_free(ignore_children); - return ret; + if (ret < 0) { + return ret; + } + + if (!c->has_backup_perm) { + c->has_backup_perm = true; + c->backup_perm = c->perm; + c->backup_shared_perm = c->shared_perm; + } + /* + * Note: it's OK if c->has_backup_perm was already set, as we can find the + * same child twice during check_perm procedure + */ + + c->perm = perm; + c->shared_perm = shared; + + return 0; } static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared) { uint64_t cumulative_perms, cumulative_shared_perms; + c->has_backup_perm = false; + c->perm = perm; c->shared_perm = shared; @@ -1965,6 +2023,12 @@ static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared) static void bdrv_child_abort_perm_update(BdrvChild *c) { + if (c->has_backup_perm) { + c->perm = c->backup_perm; + c->shared_perm = c->backup_shared_perm; + c->has_backup_perm = false; + } + bdrv_abort_perm_update(c->bs); } @@ -2062,6 +2126,8 @@ static void bdrv_replace_child_noperm(BdrvChild *child, BlockDriverState *old_bs = child->bs; int i; + assert(!child->frozen); + if (old_bs && new_bs) { assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs)); } @@ -2278,6 +2344,10 @@ void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, 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); } @@ -2303,8 +2373,6 @@ void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, bdrv_unref(backing_hd); } - bdrv_refresh_filename(bs); - out: bdrv_refresh_limits(bs, NULL); } @@ -2322,10 +2390,11 @@ out: 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; @@ -2356,13 +2425,22 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options, */ 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); @@ -2383,9 +2461,8 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options, 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: "); @@ -2394,6 +2471,12 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options, } 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 */ bdrv_set_backing_hd(bs, backing_hd, &local_err); @@ -2833,8 +2916,6 @@ static BlockDriverState *bdrv_open_inherit(const char *filename, g_free(child_key_dot); } - bdrv_refresh_filename(bs); - /* Check if any unknown options were used */ if (qdict_size(options) != 0) { const QDictEntry *entry = qdict_first(options); @@ -2902,6 +2983,74 @@ BlockDriverState *bdrv_open(const char *filename, const char *reference, 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. @@ -2929,7 +3078,8 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue, QDict *options, const BdrvChildRole *role, QDict *parent_options, - int parent_flags) + int parent_flags, + bool keep_old_opts) { assert(bs != NULL); @@ -2969,13 +3119,13 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue, */ /* 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); @@ -2987,10 +3137,12 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue, 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); @@ -3023,9 +3175,21 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue, 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) @@ -3034,13 +3198,32 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue, 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; @@ -3048,9 +3231,10 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *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); } /* @@ -3070,23 +3254,44 @@ BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue, * 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, 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, 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 */ @@ -3095,7 +3300,23 @@ int bdrv_reopen_multiple(AioContext *ctx, BlockReopenQueue *bs_queue, Error **er } 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) { @@ -3105,6 +3326,9 @@ cleanup: 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); @@ -3122,8 +3346,8 @@ int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only, 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; @@ -3176,6 +3400,101 @@ static void bdrv_reopen_perm(BlockReopenQueue *q, BlockDriverState *bs, *shared = cumulative_shared_perms; } +/* + * Take a BDRVReopenState and check if the value of 'backing' in the + * reopen_state->options QDict is valid or not. + * + * 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 @@ -3274,11 +3593,23 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, } 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) { error_propagate(errp, local_err); } else { + bdrv_refresh_filename(reopen_state->bs); error_setg(errp, "failed while preparing to reopen image '%s'", reopen_state->bs->filename); } @@ -3296,6 +3627,30 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, 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) */ @@ -3348,12 +3703,6 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, } 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 */ @@ -3411,6 +3760,11 @@ void bdrv_reopen_commit(BDRVReopenState *reopen_state) 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) { @@ -3418,10 +3772,22 @@ void bdrv_reopen_commit(BDRVReopenState *reopen_state) 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); @@ -3454,8 +3820,6 @@ void bdrv_reopen_abort(BDRVReopenState *reopen_state) if (drv->bdrv_reopen_abort) { drv->bdrv_reopen_abort(reopen_state); } - - bdrv_abort_perm_update(reopen_state->bs); } @@ -3536,7 +3900,9 @@ void bdrv_close_all(void) static bool should_update_child(BdrvChild *c, BlockDriverState *to) { - BdrvChild *to_c; + GQueue *queue; + GHashTable *found; + bool ret; if (c->role->stay_at_node) { return false; @@ -3572,14 +3938,43 @@ static bool should_update_child(BdrvChild *c, BlockDriverState *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; + * place there is the most sensible choice. + * + * We would also create a loop in any cases where @c is only + * indirectly referenced by @to. Prevent this by returning false + * if @c is found (by breadth-first search) anywhere in the whole + * subtree of @to. + */ + + ret = true; + found = g_hash_table_new(NULL, NULL); + g_hash_table_add(found, to); + queue = g_queue_new(); + g_queue_push_tail(queue, to); + + while (!g_queue_is_empty(queue)) { + BlockDriverState *v = g_queue_pop_head(queue); + BdrvChild *c2; + + QLIST_FOREACH(c2, &v->children, next) { + if (c2 == c) { + ret = false; + break; + } + + if (g_hash_table_contains(found, c2->bs)) { + continue; + } + + g_queue_push_tail(queue, c2->bs); + g_hash_table_add(found, c2->bs); } } - return true; + g_queue_free(queue); + g_hash_table_destroy(found); + + return ret; } void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to, @@ -3604,6 +3999,11 @@ void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to, 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; @@ -3725,6 +4125,7 @@ static void bdrv_check_co_entry(void *opaque) { CheckCo *cco = opaque; cco->ret = bdrv_co_check(cco->bs, cco->res, cco->fix); + aio_wait_kick(); } int bdrv_check(BlockDriverState *bs, @@ -3743,7 +4144,7 @@ int bdrv_check(BlockDriverState *bs, bdrv_check_co_entry(&cco); } else { co = qemu_coroutine_create(bdrv_check_co_entry, &cco); - qemu_coroutine_enter(co); + bdrv_coroutine_enter(bs, co); BDRV_POLL_WHILE(bs, cco.ret == -EINPROGRESS); } @@ -3782,6 +4183,8 @@ int bdrv_change_backing_file(BlockDriverState *bs, 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; } @@ -3812,6 +4215,63 @@ BlockDriverState *bdrv_find_base(BlockDriverState *bs) 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. + */ +bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base, + Error **errp) +{ + BlockDriverState *i; + + for (i = bs; i != base && i->backing; i = backing_bs(i)) { + if (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. + * 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; i = backing_bs(i)) { + 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. + */ +void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base) +{ + BlockDriverState *i; + + for (i = bs; i != base && i->backing; i = backing_bs(i)) { + 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. @@ -3861,6 +4321,14 @@ int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base, 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. @@ -3874,16 +4342,18 @@ int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base, /* success - we can delete the intermediate states, and link top->base */ /* TODO Check graph modification op blockers (BLK_PERM_GRAPH_MOD) once * we've figured out how they should work. */ - backing_file_str = backing_file_str ? backing_file_str : base->filename; + if (!backing_file_str) { + bdrv_refresh_filename(base); + backing_file_str = base->filename; + } 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, &local_err); g_slist_free(ignore_children); - if (local_err) { - ret = -EPERM; + if (ret < 0) { error_report_err(local_err); goto exit; } @@ -4033,7 +4503,7 @@ static int qsort_strcmp(const void *a, const void *b) } void bdrv_iterate_format(void (*it)(void *opaque, const char *name), - void *opaque) + void *opaque, bool read_only) { BlockDriver *drv; int count = 0; @@ -4044,6 +4514,11 @@ void bdrv_iterate_format(void (*it)(void *opaque, const char *name), 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); } @@ -4062,6 +4537,11 @@ void bdrv_iterate_format(void (*it)(void *opaque, const char *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); } @@ -4119,6 +4599,154 @@ BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp) return list; } +#define QAPI_LIST_ADD(list, element) do { \ + typeof(list) _tmp = g_new(typeof(*(list)), 1); \ + _tmp->value = (element); \ + _tmp->next = (list); \ + (list) = _tmp; \ +} while (0) + +typedef struct XDbgBlockGraphConstructor { + XDbgBlockGraph *graph; + GHashTable *graph_nodes; +} XDbgBlockGraphConstructor; + +static XDbgBlockGraphConstructor *xdbg_graph_new(void) +{ + XDbgBlockGraphConstructor *gr = g_new(XDbgBlockGraphConstructor, 1); + + gr->graph = g_new0(XDbgBlockGraph, 1); + gr->graph_nodes = g_hash_table_new(NULL, NULL); + + return gr; +} + +static XDbgBlockGraph *xdbg_graph_finalize(XDbgBlockGraphConstructor *gr) +{ + XDbgBlockGraph *graph = gr->graph; + + g_hash_table_destroy(gr->graph_nodes); + g_free(gr); + + return graph; +} + +static uintptr_t xdbg_graph_node_num(XDbgBlockGraphConstructor *gr, void *node) +{ + uintptr_t ret = (uintptr_t)g_hash_table_lookup(gr->graph_nodes, node); + + if (ret != 0) { + return ret; + } + + /* + * Start counting from 1, not 0, because 0 interferes with not-found (NULL) + * answer of g_hash_table_lookup. + */ + ret = g_hash_table_size(gr->graph_nodes) + 1; + g_hash_table_insert(gr->graph_nodes, node, (void *)ret); + + return ret; +} + +static void xdbg_graph_add_node(XDbgBlockGraphConstructor *gr, void *node, + XDbgBlockGraphNodeType type, const char *name) +{ + XDbgBlockGraphNode *n; + + n = g_new0(XDbgBlockGraphNode, 1); + + n->id = xdbg_graph_node_num(gr, node); + n->type = type; + n->name = g_strdup(name); + + QAPI_LIST_ADD(gr->graph->nodes, n); +} + +static void xdbg_graph_add_edge(XDbgBlockGraphConstructor *gr, void *parent, + const BdrvChild *child) +{ + typedef struct { + unsigned int flag; + BlockPermission num; + } PermissionMap; + + static const PermissionMap permissions[] = { + { BLK_PERM_CONSISTENT_READ, BLOCK_PERMISSION_CONSISTENT_READ }, + { BLK_PERM_WRITE, BLOCK_PERMISSION_WRITE }, + { BLK_PERM_WRITE_UNCHANGED, BLOCK_PERMISSION_WRITE_UNCHANGED }, + { BLK_PERM_RESIZE, BLOCK_PERMISSION_RESIZE }, + { BLK_PERM_GRAPH_MOD, BLOCK_PERMISSION_GRAPH_MOD }, + { 0, 0 } + }; + const PermissionMap *p; + XDbgBlockGraphEdge *edge; + + QEMU_BUILD_BUG_ON(1UL << (ARRAY_SIZE(permissions) - 1) != BLK_PERM_ALL + 1); + + edge = g_new0(XDbgBlockGraphEdge, 1); + + edge->parent = xdbg_graph_node_num(gr, parent); + edge->child = xdbg_graph_node_num(gr, child->bs); + edge->name = g_strdup(child->name); + + for (p = permissions; p->flag; p++) { + if (p->flag & child->perm) { + QAPI_LIST_ADD(edge->perm, p->num); + } + if (p->flag & child->shared_perm) { + QAPI_LIST_ADD(edge->shared_perm, p->num); + } + } + + QAPI_LIST_ADD(gr->graph->edges, edge); +} + + +XDbgBlockGraph *bdrv_get_xdbg_block_graph(Error **errp) +{ + BlockBackend *blk; + BlockJob *job; + BlockDriverState *bs; + BdrvChild *child; + XDbgBlockGraphConstructor *gr = xdbg_graph_new(); + + for (blk = blk_all_next(NULL); blk; blk = blk_all_next(blk)) { + char *allocated_name = NULL; + const char *name = blk_name(blk); + + if (!*name) { + name = allocated_name = blk_get_attached_dev_id(blk); + } + xdbg_graph_add_node(gr, blk, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_BACKEND, + name); + g_free(allocated_name); + if (blk_root(blk)) { + xdbg_graph_add_edge(gr, blk, blk_root(blk)); + } + } + + for (job = block_job_next(NULL); job; job = block_job_next(job)) { + GSList *el; + + xdbg_graph_add_node(gr, job, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_JOB, + job->job.id); + for (el = job->nodes; el; el = el->next) { + xdbg_graph_add_edge(gr, job, (BdrvChild *)el->data); + } + } + + QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) { + xdbg_graph_add_node(gr, bs, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_DRIVER, + bs->node_name); + QLIST_FOREACH(child, &bs->children, next) { + xdbg_graph_add_edge(gr, bs, child); + } + } + + return xdbg_graph_finalize(gr); +} + BlockDriverState *bdrv_lookup_bs(const char *device, const char *node_name, Error **errp) @@ -4274,16 +4902,6 @@ bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs) return bs->supported_zero_flags & BDRV_REQ_MAY_UNMAP; } -const char *bdrv_get_encrypted_filename(BlockDriverState *bs) -{ - if (bs->backing && bs->backing->bs->encrypted) - return bs->backing_file; - else if (bs->encrypted) - return bs->filename; - else - return NULL; -} - void bdrv_get_backing_filename(BlockDriverState *bs, char *filename, int filename_size) { @@ -4307,11 +4925,12 @@ int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) return drv->bdrv_get_info(bs, bdi); } -ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs) +ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs, + Error **errp) { BlockDriver *drv = bs->drv; if (drv && drv->bdrv_get_specific_info) { - return drv->bdrv_get_specific_info(bs); + return drv->bdrv_get_specific_info(bs, errp); } return NULL; } @@ -4391,7 +5010,6 @@ BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, int is_protocol = 0; BlockDriverState *curr_bs = NULL; BlockDriverState *retval = NULL; - Error *local_error = NULL; if (!bs || !bs->drv || !backing_file) { return NULL; @@ -4399,7 +5017,6 @@ BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, 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); @@ -4408,41 +5025,43 @@ BlockDriverState *bdrv_find_backing_image(BlockDriverState *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; @@ -4453,7 +5072,6 @@ BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, g_free(filename_full); g_free(backing_file_full); - g_free(filename_tmp); return retval; } @@ -4542,6 +5160,7 @@ static void coroutine_fn bdrv_co_invalidate_cache(BlockDriverState *bs, if (parent->role->activate) { parent->role->activate(parent, &local_err); if (local_err) { + bs->open_flags |= BDRV_O_INACTIVE; error_propagate(errp, local_err); return; } @@ -4560,6 +5179,7 @@ static void coroutine_fn bdrv_invalidate_cache_co_entry(void *opaque) InvalidateCacheCo *ico = opaque; bdrv_co_invalidate_cache(ico->bs, ico->errp); ico->done = true; + aio_wait_kick(); } void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp) @@ -4576,7 +5196,7 @@ void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp) bdrv_invalidate_cache_co_entry(&ico); } else { co = qemu_coroutine_create(bdrv_invalidate_cache_co_entry, &ico); - qemu_coroutine_enter(co); + bdrv_coroutine_enter(bs, co); BDRV_POLL_WHILE(bs, !ico.done); } } @@ -4938,17 +5558,17 @@ void bdrv_img_create(const char *filename, const char *fmt, 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; @@ -5069,6 +5689,9 @@ void bdrv_detach_aio_context(BlockDriverState *bs) bdrv_detach_aio_context(child->bs); } + if (bs->quiesce_counter) { + aio_enable_external(bs->aio_context); + } bs->aio_context = NULL; } @@ -5082,6 +5705,10 @@ void bdrv_attach_aio_context(BlockDriverState *bs, return; } + if (bs->quiesce_counter) { + aio_disable_external(new_context); + } + bs->aio_context = new_context; QLIST_FOREACH(child, &bs->children, next) { @@ -5103,18 +5730,16 @@ void bdrv_attach_aio_context(BlockDriverState *bs, 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) { - AioContext *ctx = bdrv_get_aio_context(bs); - - aio_disable_external(ctx); - bdrv_parent_drained_begin(bs, NULL, false); - bdrv_drain(bs); /* ensure there are no in-flight requests */ - - while (aio_poll(ctx, false)) { - /* wait for all bottom halves to execute */ + if (bdrv_get_aio_context(bs) == new_context) { + return; } + bdrv_drained_begin(bs); bdrv_detach_aio_context(bs); /* This function executes in the old AioContext so acquire the new one in @@ -5122,8 +5747,7 @@ void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context) */ aio_context_acquire(new_context); bdrv_attach_aio_context(bs, new_context); - bdrv_parent_drained_end(bs, NULL, false); - aio_enable_external(ctx); + bdrv_drained_end(bs); aio_context_release(new_context); } @@ -5277,33 +5901,113 @@ out: 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 @@ -5319,92 +6023,108 @@ static bool append_open_options(QDict *d, BlockDriverState *bs) void bdrv_refresh_filename(BlockDriverState *bs) { 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; } - /* This BDS's file name will most probably depend on its file's name, so - * refresh that first */ - if (bs->file) { - bdrv_refresh_filename(bs->file->bs); + /* This BDS's file name may depend on any of its children's file names, so + * refresh those first */ + QLIST_FOREACH(child, &bs->children, next) { + bdrv_refresh_filename(child->bs); + } + + if (bs->implicit) { + /* For implicit nodes, just copy everything from the single child */ + child = QLIST_FIRST(&bs->children); + assert(QLIST_NEXT(child, next) == NULL); + + pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), + child->bs->exact_filename); + pstrcpy(bs->filename, sizeof(bs->filename), child->bs->filename); + + bs->full_open_options = qobject_ref(child->bs->full_open_options); + + 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)); @@ -5412,6 +6132,33 @@ void bdrv_refresh_filename(BlockDriverState *bs) } } +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