X-Git-Url: http://git.vrable.net/?a=blobdiff_plain;f=bluesky%2Fcleaner.c;h=3ca15b8adfff87ec4affd402b310c95c66c86d87;hb=173738187e4798ff42d3be002f65c142c3b2abc9;hp=ca61d94357e8e6e69b00a84e382824f2bad6011b;hpb=e692553e85c46324aaeb36c6e737339ddae115a0;p=bluesky.git

diff --git a/bluesky/cleaner.c b/bluesky/cleaner.c
index ca61d94..3ca15b8 100644
--- a/bluesky/cleaner.c
+++ b/bluesky/cleaner.c
@@ -21,23 +21,106 @@
  * rewriting log segments where needed and deleting old segments, is handled by
  * the in-cloud cleaner component. */
 
+/* A specialized function for loading an object from the cloud, used just by
+ * the cleaner.  When the cleaner runs, it will produce new objects that have
+ * the same object ID as before, differing only in the outgoing link locations
+ * as a result of cleaning.  We can't use the normal functions for loading
+ * objects since those can only deal with one version of an object.  Instead,
+ * we load the cleaned object with this function, and then merge the state into
+ * the official object as needed.
+ *
+ * The bluesky_cleaner_deserialize function is like
+ * bluesky_deserialize_cloudlog, but does a more limited deserialization and
+ * keeps the returned item entirely separate from any in-memory BlueSkyCloudLog
+ * objects. */
+
+typedef struct {
+    BlueSkyCloudLogType type;
+    BlueSkyCloudID id;
+    BlueSkyCloudPointer location;
+    uint64_t inum;
+    GArray *links;
+} BlueSkyCleanerItem;
+
+typedef struct {
+    BlueSkyCloudID id;
+    BlueSkyCloudPointer location;
+} BlueSkyCleanerLink;
+
+static BlueSkyCleanerItem *bluesky_cleaner_deserialize(BlueSkyRCStr *raw)
+{
+    const char *data = raw->data;
+    size_t len = raw->len;
+    const char *data1, *data2, *data3;
+    size_t len1, len2, len3;
+
+    g_assert(len > 4);
+    if (len < sizeof(struct cloudlog_header)
+        || memcmp(data, CLOUDLOG_MAGIC, 4) != 0)
+    {
+        g_warning("Deserializing garbage cloud log item from cleaner!");
+        return NULL;
+    };
+
+    struct cloudlog_header *header = (struct cloudlog_header *)data;
+    len1 = GUINT32_FROM_LE(header->size1);
+    len2 = GUINT32_FROM_LE(header->size2);
+    len3 = GUINT32_FROM_LE(header->size3);
+    data1 = data + sizeof(struct cloudlog_header);
+    data2 = data1 + len1;
+    data3 = data2 + len2;
+    g_assert(data3 + len3 - data <= len);
+
+    BlueSkyCleanerItem *item = g_new0(BlueSkyCleanerItem, 1);
+    item->type = header->type - '0';
+    item->inum = GUINT64_FROM_LE(header->inum);
+    memcpy(&item->id, &header->id, sizeof(BlueSkyCloudID));
+
+    int link_count = len2 / sizeof(BlueSkyCloudID);
+    g_print("Outgoing links: %d\n", link_count);
+    item->links = g_array_new(FALSE, TRUE, sizeof(BlueSkyCleanerLink));
+    for (int i = 0; i < link_count; i++) {
+        BlueSkyCleanerLink link;
+
+        g_assert(len2 >= sizeof(link.id));
+        memcpy(&link.id, data2, sizeof(link.id));
+        data2 += sizeof(link.id); len2 -= sizeof(link.id);
+
+        g_assert(len3 >= sizeof(link.location));
+        memcpy(&link.location, data3, sizeof(link.location));
+        data3 += sizeof(link.location); len3 -= sizeof(link.location);
+
+        g_array_append_val(item->links, link);
+    }
+
+    return item;
+}
+
+static void bluesky_cleaner_item_free(BlueSkyCleanerItem *item)
+{
+    if (item == NULL)
+        return;
+    g_array_unref(item->links);
+    g_free(item);
+}
+
 /* Check the cleaner's logs to find the a more recent checkpoint record.  This
  * should be called occasionally to see if the cleaner has done any work since
  * our last check. */
-void bluesky_cleaner_find_checkpoint(BlueSkyFS *fs)
+static BlueSkyCleanerItem *bluesky_cleaner_find_checkpoint(BlueSkyFS *fs)
 {
     char *prefix = g_strdup_printf("log-%08d", BLUESKY_CLOUD_DIR_CLEANER);
     char *last_segment = bluesky_store_lookup_last(fs->store, prefix);
     g_free(prefix);
     if (last_segment == NULL)
-        return;
+        return NULL;
 
     g_print("Last cloud log segment: %s\n", last_segment);
     int seq = atoi(last_segment + 13);
     g_free(last_segment);
 
     if (seq <= fs->log_state->latest_cleaner_seq_seen)
-        return;
+        return NULL;
 
     g_print("New log segment appeared in cleaner directory: %d\n", seq);
 
@@ -59,10 +142,214 @@ void bluesky_cleaner_find_checkpoint(BlueSkyFS *fs)
         length = item->length;
     }
 
-    if (length > 0) {
-        g_print("Last object: %"PRIu64" + %"PRIu64"\n", offset, length);
+    if (length == 0) {
+        bluesky_cachefile_unref(cachefile);
+        g_mutex_unlock(cachefile->lock);
+        return NULL;
     }
 
+    g_print("Found a cleaner checkpoint record.\n");
+
+    BlueSkyRCStr *data = bluesky_cachefile_map_raw(cachefile, offset, length);
     bluesky_cachefile_unref(cachefile);
     g_mutex_unlock(cachefile->lock);
+
+    BlueSkyCleanerItem *checkpoint = bluesky_cleaner_deserialize(data);
+    checkpoint->location.directory = BLUESKY_CLOUD_DIR_CLEANER;
+    checkpoint->location.directory = seq;
+    bluesky_string_unref(data);
+
+    return checkpoint;
+}
+
+static BlueSkyCleanerItem *cleaner_load_item(BlueSkyFS *fs,
+                                             BlueSkyCloudPointer location)
+{
+    g_print("Loading item %d/%d/%d...\n", location.directory, location.sequence, location.offset);
+
+    BlueSkyCacheFile *cachefile;
+    cachefile = bluesky_cachefile_lookup(fs, location.directory,
+                                         location.sequence, TRUE);
+    while (!cachefile->complete)
+        g_cond_wait(cachefile->cond, cachefile->lock);
+
+    /* TODO: Ought to check that we are loading an item which validated? */
+    BlueSkyRCStr *data = bluesky_cachefile_map_raw(cachefile, location.offset,
+                                                   location.size);
+    bluesky_cachefile_unref(cachefile);
+    g_mutex_unlock(cachefile->lock);
+
+    BlueSkyCleanerItem *item = bluesky_cleaner_deserialize(data);
+    bluesky_string_unref(data);
+
+    return item;
+}
+
+/* Does the item at the given cloud location from the cleaner need merging?  An
+ * item in the primary log does not need to be merged, as by definition we
+ * already know about it.  Similarly, old items in the cleaner's log--those
+ * that we have already seen from a previous merge--do not need to be mergd
+ * again. */
+gboolean needs_merging(BlueSkyFS *fs, BlueSkyCloudPointer location)
+{
+    if (location.directory == BLUESKY_CLOUD_DIR_PRIMARY)
+        return FALSE;
+
+    if (location.directory == BLUESKY_CLOUD_DIR_CLEANER
+        && location.sequence <= fs->log_state->latest_cleaner_seq_seen)
+        return FALSE;
+
+    return TRUE;
+}
+
+/* For an inode which has been modified by the cleaner and must be flushed out
+ * to cloud storage, mark it as appropriately dirty.  We will bypass writingt
+ * the inode to the journal if possible--but if there have ben other
+ * uncommitted changes besides what the cleaner did then we will force a
+ * journal write as well since the cloud shouldn't contain newer data than the
+ * journal.  Inode must be locked. */
+static void cleaner_flush_inode(BlueSkyInode *inode)
+{
+    // if (inode->change_commit != inode->change_count) {
+    if (TRUE) {
+        /* bluesky_inode_start_sync schedules a flush to the cloud so we're all
+         * done. */
+        bluesky_inode_start_sync(inode);
+        return;
+    }
+
+    g_assert(inode->unlogged_list == NULL);
+
+    bluesky_list_unlink(&inode->fs->dirty_list, inode->dirty_list);
+    inode->dirty_list = bluesky_list_prepend(&inode->fs->dirty_list, inode);
+    inode->change_cloud = inode->change_count;
+}
+
+static void merge_inode(BlueSkyFS *fs, BlueSkyCleanerItem *cleaner_inode)
+{
+    /* There are two versions we are concerned with: cleaner_ is for the data
+     * stored in the cleaner's log, and proxy_ is for our most recent version,
+     * which the cleaner might or might not know about. */
+    uint64_t inum = cleaner_inode->inum;
+
+    g_print("Merging inode %"PRIu64" from cleaner\n", inum);
+
+    g_mutex_lock(fs->lock);
+    InodeMapEntry *entry = bluesky_inode_map_lookup(fs->inode_map, inum, 0);
+    if (entry == NULL) {
+        /* Inode doesn't exist: it was probably deleted so keep it that way. */
+        g_mutex_unlock(fs->lock);
+        return;
+    }
+
+    BlueSkyCloudLog *proxy_item = entry->item;
+    g_mutex_lock(proxy_item->lock);
+    //BlueSkyCloudPointer proxy_location = entry->item->location;
+    //BlueSkyCloudID proxy_id = entry->item->id;
+    g_mutex_unlock(proxy_item->lock);
+    g_mutex_unlock(fs->lock);
+
+    /* If the cleaner and the proxy have the same ID, and if the proxy's
+     * in-memory copy is unmodified, then we can simply use the cleaner's
+     * version of the inode. */
+    /* TODO */
+
+    /* Merge file data together for a regular file.  Iterate over the file
+     * blocks in the proxy's copy of the inode.  If the block ID is unchanged
+     * in the cleaner but the location was updated, then update the location in
+     * the cleaner because the block was relocated.  Otherwise ignore the
+     * cleaner's version for that block because the proxy's information is more
+     * recent. */
+    BlueSkyInode *proxy_inode = bluesky_get_inode(fs, inum);
+    g_mutex_lock(proxy_inode->lock);
+    if (proxy_inode->type == BLUESKY_REGULAR) {
+        for (int i = 0; i < proxy_inode->blocks->len; i++) {
+            BlueSkyBlock *b = &g_array_index(proxy_inode->blocks,
+                                             BlueSkyBlock, i);
+            if (b->type != BLUESKY_BLOCK_REF)
+                continue;
+            if (i >= cleaner_inode->links->len)
+                continue;
+            BlueSkyCleanerLink *cb = &g_array_index(cleaner_inode->links,
+                                                    BlueSkyCleanerLink, i);
+            if (memcmp(&b->ref->id, &cb->id, sizeof(BlueSkyCloudPointer)) != 0)
+                continue;
+
+            g_print("  Updating block %d pointer\n", i);
+            b->ref->location = cb->location;
+        }
+    }
+    cleaner_flush_inode(proxy_inode);
+    g_mutex_unlock(proxy_inode->lock);
+
+    /* Mark the inode as modified so it will get written back to the cloud.  We
+     * don't actually need to force a synchronous write to our local journal
+     * since there have been no logical modifications. */
+#if 0
+    g_mutex_lock(inode->fs->lock);
+    bluesky_list_unlink(&inode->fs->unlogged_list, inode->unlogged_list);
+    inode->unlogged_list = bluesky_list_prepend(&inode->fs->unlogged_list, inode);
+    g_mutex_unlock(inode->fs->lock);
+#endif
+}
+
+void bluesky_cleaner_merge(BlueSkyFS *fs)
+{
+    BlueSkyCleanerItem *checkpoint = bluesky_cleaner_find_checkpoint(fs);
+
+    if (checkpoint == NULL) {
+        g_warning("Unable to load cleaner checkpoint record!");
+        return;
+    }
+
+    /* Iterate over each of the inode map sections in the checkpoint */
+    for (int i = 0; i < checkpoint->links->len; i++) {
+        BlueSkyCleanerLink *link = &g_array_index(checkpoint->links,
+                                                  BlueSkyCleanerLink, i);
+        if (!needs_merging(fs, link->location))
+            continue;
+
+        BlueSkyCleanerItem *imap = cleaner_load_item(fs, link->location);
+        if (imap == NULL) {
+            g_warning("Unable to load cleaner inode map");
+            continue;
+        }
+
+        /* Iterate over all inodes found in the inode map section */
+        for (int j = 0; j < imap->links->len; j++) {
+            BlueSkyCleanerLink *link = &g_array_index(imap->links,
+                                                      BlueSkyCleanerLink, j);
+            if (!needs_merging(fs, link->location))
+                continue;
+            BlueSkyCleanerItem *inode = cleaner_load_item(fs, link->location);
+            if (inode != NULL) {
+                merge_inode(fs, inode);
+            }
+            bluesky_cleaner_item_free(inode);
+        }
+
+        bluesky_cleaner_item_free(imap);
+    }
+
+    fs->log_state->latest_cleaner_seq_seen = checkpoint->location.sequence;
+    bluesky_cleaner_item_free(checkpoint);
+}
+
+/* Run the cleaner as a background task. */
+static gpointer cleaner_thread(BlueSkyFS *fs)
+{
+    while (TRUE) {
+        struct timespec delay;
+        delay.tv_sec = 30;
+        delay.tv_nsec = 0;
+        nanosleep(&delay, NULL);
+        bluesky_cleaner_merge(fs);
+    }
+
+    return NULL;
+}
+
+void bluesky_cleaner_thread_launch(BlueSkyFS *fs)
+{
+    g_thread_create((GThreadFunc)cleaner_thread, fs, FALSE, NULL);
 }