Basic filesystem journaling.
[bluesky.git] / bluesky / inode.c
index 30974ca..a0b3c6a 100644 (file)
@@ -44,6 +44,13 @@ void bluesky_inode_update_ctime(BlueSkyInode *inode, gboolean update_mtime)
 
     if (bluesky_options.writethrough_cache)
         bluesky_file_flush(inode, NULL);
+
+    g_mutex_lock(inode->fs->lock);
+    bluesky_list_unlink(&inode->fs->dirty_list, inode->dirty_list);
+    inode->dirty_list = bluesky_list_prepend(&inode->fs->dirty_list, inode);
+    bluesky_list_unlink(&inode->fs->accessed_list, inode->accessed_list);
+    inode->accessed_list = bluesky_list_prepend(&inode->fs->accessed_list, inode);
+    g_mutex_unlock(inode->fs->lock);
 }
 
 /* Unfortunately a glib hash table is only guaranteed to be able to store
@@ -76,6 +83,7 @@ BlueSkyFS *bluesky_new_fs(gchar *name)
                                   bluesky_fs_key_equal_func);
     fs->next_inum = BLUESKY_ROOT_INUM + 1;
     fs->store = bluesky_store_new("file");
+    fs->flushd_lock = g_mutex_new();
 
     return fs;
 }
@@ -92,17 +100,20 @@ BlueSkyFS *bluesky_init_fs(gchar *name, BlueSkyStore *store)
             fs->name = g_strdup(name);
             return fs;
         }
+        bluesky_string_unref(data);
     }
 
     g_print("Initializing fresh filesystem\n");
     BlueSkyFS *fs = bluesky_new_fs(name);
     fs->store = store;
+    fs->log = bluesky_log_new("journal");
 
     BlueSkyInode *root = bluesky_new_inode(BLUESKY_ROOT_INUM, fs,
                                            BLUESKY_DIRECTORY);
     root->nlink = 1;
     root->mode = 0755;
     bluesky_insert_inode(fs, root);
+    bluesky_inode_update_ctime(root, TRUE);
 
     bluesky_inode_flush(fs, root);
     bluesky_superblock_flush(fs);
@@ -119,8 +130,60 @@ void bluesky_inode_ref(BlueSkyInode *inode)
 void bluesky_inode_unref(BlueSkyInode *inode)
 {
     if (g_atomic_int_dec_and_test(&inode->refcount)) {
-        g_error("Reference count for inode %"PRIu64" dropped to zero!\n",
-                inode->inum);
+        if (bluesky_verbose) {
+            g_log("bluesky/inode", G_LOG_LEVEL_DEBUG,
+                  "Reference count for inode %"PRIu64" dropped to zero.",
+                  inode->inum);
+        }
+
+        /* Sanity check: Is the inode clean? */
+        if (inode->change_commit < inode->change_count
+                || inode->accessed_list != NULL
+                || inode->dirty_list != NULL) {
+            g_warning("Dropping inode which is not clean (commit %"PRIi64" < change %"PRIi64"; accessed_list = %p; dirty_list = %p)\n", inode->change_commit, inode->change_count, inode->accessed_list, inode->dirty_list);
+        }
+
+        /* These shouldn't be needed, but in case the above warning fires and
+         * we delete the inode anyway, we ought to be sure the inode is not on
+         * any LRU list. */
+        g_mutex_lock(inode->fs->lock);
+        bluesky_list_unlink(&inode->fs->accessed_list, inode->accessed_list);
+        bluesky_list_unlink(&inode->fs->dirty_list, inode->dirty_list);
+        g_mutex_unlock(inode->fs->lock);
+
+        /* Free file type specific data.  It should be an error for there to be
+         * dirty data to commit when the reference count has reaches zero. */
+        switch (inode->type) {
+        case BLUESKY_REGULAR:
+            for (int i = 0; i < inode->blocks->len; i++) {
+                BlueSkyBlock *b = &g_array_index(inode->blocks,
+                                                 BlueSkyBlock, i);
+                if (b->type == BLUESKY_BLOCK_DIRTY) {
+                    g_error("Deleting an inode with dirty file data!");
+                }
+                g_free(b->ref);
+                bluesky_string_unref(b->data);
+            }
+            g_array_unref(inode->blocks);
+            break;
+
+        case BLUESKY_DIRECTORY:
+            g_hash_table_destroy(inode->dirhash);
+            g_hash_table_destroy(inode->dirhash_folded);
+            g_sequence_free(inode->dirents);
+            break;
+
+        case BLUESKY_SYMLINK:
+            g_free(inode->symlink_contents);
+            break;
+
+        default:
+            break;
+        }
+
+        g_mutex_free(inode->lock);
+
+        g_free(inode);
     }
 }
 
@@ -196,6 +259,10 @@ BlueSkyInode *bluesky_get_inode(BlueSkyFS *fs, uint64_t inum)
 
     if (inode != NULL) {
         bluesky_inode_ref(inode);
+
+        /* FIXME: We assume we can atomically update the in-memory access time
+         * without a lock. */
+        inode->access_time = bluesky_get_current_time();
     }
 
     g_mutex_unlock(fs->lock);
@@ -242,6 +309,13 @@ void bluesky_inode_start_sync(BlueSkyInode *inode, BlueSkyStoreAsync *barrier)
     char key[64];
     sprintf(key, "inode-%016"PRIx64, inode->inum);
 
+    BlueSkyLogItem *log_item = bluesky_log_item_new();
+    log_item->key = g_strdup(key);
+    log_item->data = data;
+    bluesky_string_ref(data);
+    bluesky_log_item_submit(log_item, fs->log);
+    bluesky_log_item_finish(log_item);
+
     BlueSkyStoreAsync *async = bluesky_store_async_new(fs->store);
     async->op = STORE_OP_PUT;
     async->key = g_strdup(key);
@@ -259,30 +333,48 @@ void bluesky_inode_do_sync(BlueSkyInode *inode)
     BlueSkyStoreAsync *barrier = bluesky_store_async_new(inode->fs->store);
     barrier->op = STORE_OP_BARRIER;
 
-    g_log("bluesky/inode", G_LOG_LEVEL_DEBUG,
-          "Synchronous writeback for inode %"PRIu64"...", inode->inum);
+    if (bluesky_verbose) {
+        g_log("bluesky/inode", G_LOG_LEVEL_DEBUG,
+            "Synchronous writeback for inode %"PRIu64"...", inode->inum);
+    }
     bluesky_inode_start_sync(inode, barrier);
     bluesky_store_async_submit(barrier);
     bluesky_store_async_wait(barrier);
     bluesky_store_async_unref(barrier);
-    g_log("bluesky/inode", G_LOG_LEVEL_DEBUG,
-          "Writeback for inode %"PRIu64" complete", inode->inum);
+    if (bluesky_verbose) {
+        g_log("bluesky/inode", G_LOG_LEVEL_DEBUG,
+              "Writeback for inode %"PRIu64" complete", inode->inum);
+    }
 }
 
 static void complete_inode_fetch(BlueSkyStoreAsync *async, BlueSkyInode *inode)
 {
-    g_print("Completing fetch of inode %"PRIu64"...\n", inode->inum);
+    if (bluesky_verbose) {
+        g_log("bluesky/inode", G_LOG_LEVEL_DEBUG,
+              "Completing fetch of inode %"PRIu64"...", inode->inum);
+    }
 
     if (async->result != 0
         || !bluesky_deserialize_inode(inode, async->data->data))
     {
-        g_print("    failed to load inode, cleaning up\n");
+        if (bluesky_verbose) {
+            g_log("bluesky/inode", G_LOG_LEVEL_DEBUG,
+                  "    failed to load inode, cleaning up");
+        }
         g_mutex_lock(inode->fs->lock);
         g_hash_table_remove(inode->fs->inodes, &inode->inum);
+        bluesky_list_unlink(&inode->fs->accessed_list, inode->accessed_list);
+        inode->accessed_list = NULL;
         g_mutex_unlock(inode->fs->lock);
         bluesky_inode_unref(inode);
     }
 
+    inode->access_time = bluesky_get_current_time();
+    g_mutex_lock(inode->fs->lock);
+    bluesky_list_unlink(&inode->fs->accessed_list, inode->accessed_list);
+    inode->accessed_list = bluesky_list_prepend(&inode->fs->accessed_list, inode);
+    g_mutex_unlock(inode->fs->lock);
+
     g_mutex_unlock(inode->lock);
     bluesky_inode_unref(inode);
 }
@@ -298,6 +390,7 @@ void bluesky_inode_fetch(BlueSkyFS *fs, uint64_t inum)
     sprintf(key, "inode-%016"PRIx64, inum);
 
     BlueSkyInode *inode = bluesky_new_inode(inum, fs, BLUESKY_PENDING);
+    inode->change_count = 0;
     bluesky_inode_ref(inode);       // Extra ref held by fetching process
     g_mutex_lock(inode->lock);
     bluesky_insert_inode(fs, inode);
@@ -330,5 +423,5 @@ void bluesky_superblock_flush(BlueSkyFS *fs)
     bluesky_store_async_submit(async);
     bluesky_store_async_unref(async);
 
-    bluesky_store_sync(fs->store);
+    //bluesky_store_sync(fs->store);
 }