lib-storage: LAYOUT=index no longer keeps list index locked while creating mailbox.

Mailbox opening can be slow and complicated and could even try to lock the
list index again. So it's a bit more racy now, but all mailbox formats can
already handle races with mailbox creation.

diff --git a/src/lib-storage/list/mailbox-list-index-backend.c b/src/lib-storage/list/mailbox-list-index-backend.c
index 16d745ce39d391d83ad98efa0064c9705aac9c98..b0eb36e32108ae3b0da4575ccfc4dc9bba0cd84d 100644 (file)
--- a/src/lib-storage/list/mailbox-list-index-backend.c
+++ b/src/lib-storage/list/mailbox-list-index-backend.c
@@ -262,9 +262,8 @@ index_list_mailbox_create_dir(struct index_mailbox_list *list, const char *name)
 
 static int
 index_list_mailbox_create_selectable(struct mailbox *box,
-                                    const struct mailbox_update *update)
+                                    const guid_128_t mailbox_guid)
 {
-       struct index_list_mailbox *ibox = INDEX_LIST_STORAGE_CONTEXT(box);
        struct index_mailbox_list *list =
                (struct index_mailbox_list *)box->list;
        struct mailbox_list_index *ilist = INDEX_LIST_CONTEXT(box->list);
@@ -272,7 +271,7 @@ index_list_mailbox_create_selectable(struct mailbox *box,
        struct mailbox_list_index_record rec;
        struct mailbox_list_index_node *node;
        const void *data;
-       bool expunged, created, success;
+       bool expunged, created;
        uint32_t seq;
 
        if (mailbox_list_index_sync_begin(&list->list, &sync_ctx) < 0)
@@ -297,11 +296,10 @@ index_list_mailbox_create_selectable(struct mailbox *box,
        node->flags = 0;
        mail_index_update_flags(sync_ctx->trans, seq, MODIFY_REPLACE, 0);
 
-       memcpy(rec.guid, update->mailbox_guid, sizeof(rec.guid));
+       memcpy(rec.guid, mailbox_guid, sizeof(rec.guid));
        mail_index_update_ext(sync_ctx->trans, seq, ilist->ext_id, &rec, NULL);
 
-       success = ibox->module_ctx.super.create_box(box, update, FALSE) == 0;
-       if (mailbox_list_index_sync_end(&sync_ctx, success) < 0) {
+       if (mailbox_list_index_sync_end(&sync_ctx, TRUE) < 0) {
                /* make sure we forget any changes done internally */
                mailbox_list_index_reset(ilist);
                return -1;
@@ -313,6 +311,7 @@ static int
 index_list_mailbox_create(struct mailbox *box,
                          const struct mailbox_update *update, bool directory)
 {
+       struct index_list_mailbox *ibox = INDEX_LIST_STORAGE_CONTEXT(box);
        struct index_mailbox_list *list =
                (struct index_mailbox_list *)box->list;
        struct mailbox_update new_update;
@@ -339,11 +338,19 @@ index_list_mailbox_create(struct mailbox *box,
                        new_update = *update;
                if (guid_128_is_empty(new_update.mailbox_guid))
                        guid_128_generate(new_update.mailbox_guid);
-               ret = index_list_mailbox_create_selectable(box, &new_update);
+               ret = index_list_mailbox_create_selectable(box, new_update.mailbox_guid);
                if (ret < 0) {
                        mail_storage_copy_list_error(box->storage, box->list);
                        return -1;
                }
+               if (ret > 0) {
+                       /* mailbox entry was created. create the mailbox
+                          itself now after the mailbox list index is already
+                          unlocked (to avoid deadlocks in case the create_box()
+                          goes back to updating mailbox list index). */
+                       if (ibox->module_ctx.super.create_box(box, update, FALSE) < 0)
+                               return -1;
+               }
        } else {
                ret = 0;
        }