+/* Writing of data to the cloud in log segments and tracking the location of
+ * various pieces of data (both where in the cloud and where cached locally).
+ * */
+
+typedef struct {
+ char bytes[16];
+} BlueSkyCloudID;
+
+typedef struct {
+ uint32_t directory;
+ uint32_t sequence;
+ uint32_t offset;
+ uint32_t size;
+} BlueSkyCloudPointer;
+
+typedef enum {
+ LOGTYPE_INVALID = -1,
+ LOGTYPE_UNKNOWN = 0,
+ LOGTYPE_DATA = 1,
+ LOGTYPE_INODE = 2,
+ LOGTYPE_INODE_MAP = 3,
+ LOGTYPE_CHECKPOINT = 4,
+
+ /* Used only as metadata in the local journal, not loaded as a
+ * BlueSkyCloudLogState nor stored in the cloud */
+ LOGTYPE_JOURNAL_MARKER = 16,
+ LOGTYPE_JOURNAL_CHECKPOINT = 17,
+} BlueSkyCloudLogType;
+
+/* Headers that go on items in local log segments and cloud log segments. */
+struct log_header {
+ uint32_t magic; // HEADER_MAGIC
+ uint8_t type; // Object type + '0'
+ uint32_t offset; // Starting byte offset of the log header
+ uint32_t size1; // Size of the data item (bytes)
+ uint32_t size2; //
+ uint32_t size3; //
+ uint64_t inum; // Inode which owns this data, if any
+ BlueSkyCloudID id; // Object identifier
+} __attribute__((packed));
+
+struct log_footer {
+ uint32_t magic; // FOOTER_MAGIC
+ uint32_t crc; // Computed from log_header to log_footer.magic
+} __attribute__((packed));
+
+struct cloudlog_header {
+ char magic[4];
+ uint8_t crypt_auth[CRYPTO_HASH_SIZE];
+ uint8_t crypt_iv[CRYPTO_BLOCK_SIZE];
+ uint8_t type;
+ BlueSkyCloudID id;
+ uint64_t inum;
+ uint32_t size1, size2, size3;
+} __attribute__((packed));
+
+#define JOURNAL_MAGIC "\nLog"
+#define CLOUDLOG_MAGIC "AgI-"
+#define CLOUDLOG_MAGIC_ENCRYPTED "AgI=" // CLOUDLOG_MAGIC[3] ^= 0x10
+
+/* A record which tracks an object which has been written to a local log,
+ * cached, locally, and/or written to the cloud. */
+#define CLOUDLOG_JOURNAL 0x01
+#define CLOUDLOG_CLOUD 0x02
+#define CLOUDLOG_CACHE 0x04
+#define CLOUDLOG_UNCOMMITTED 0x10
+struct BlueSkyCloudLog {
+ gint refcount;
+ GMutex *lock;
+ GCond *cond;
+
+ BlueSkyFS *fs;
+
+ BlueSkyCloudLogType type;
+
+ // Bitmask of CLOUDLOG_* flags indicating where the object exists.
+ int location_flags;
+ int pending_read, pending_write;
+
+ // A stable identifier for the object (only changes when authenticated data
+ // is written out, but stays the same when the in-cloud cleaner relocates
+ // the object).
+ BlueSkyCloudID id;
+
+ // The inode which owns this data, if any, and an offset.
+ uint64_t inum;
+ int32_t inum_offset;
+
+ // The size of encrypted object data, not including any headers
+ int data_size;
+
+ // The location of the object in the cloud, if available.
+ BlueSkyCloudPointer location;
+
+ // TODO: Location in journal/cache
+ int log_seq, log_offset, log_size;
+
+ // Pointers to other objects. Each link counts towards the reference count
+ // of the pointed-to object. To avoid memory leaks there should be no
+ // cycles in the reference graph.
+ GArray *links;
+
+ // Serialized data, if available in memory (otherwise NULL), and a lock
+ // count which tracks if there are users that require the data to be kept
+ // around.
+ BlueSkyRCStr *data;
+ int data_lock_count;
+};
+
+/* Serialize objects into a log segment to be written to the cloud. */
+struct BlueSkyCloudLogState {
+ GString *data;
+ BlueSkyCloudPointer location;
+ GList *inode_list;
+ GSList *writeback_list; // Items which are being serialized right now
+ GList *pending_segments; // Segments which are being uploaded now
+};
+
+gboolean bluesky_cloudlog_equal(gconstpointer a, gconstpointer b);
+guint bluesky_cloudlog_hash(gconstpointer a);
+BlueSkyCloudLog *bluesky_cloudlog_new(BlueSkyFS *fs, const BlueSkyCloudID *id);
+gchar *bluesky_cloudlog_id_to_string(BlueSkyCloudID id);
+BlueSkyCloudID bluesky_cloudlog_id_from_string(const gchar *idstr);
+void bluesky_cloudlog_threads_init(BlueSkyFS *fs);
+void bluesky_cloudlog_ref(BlueSkyCloudLog *log);
+void bluesky_cloudlog_unref(BlueSkyCloudLog *log);
+void bluesky_cloudlog_unref_delayed(BlueSkyCloudLog *log);
+void bluesky_cloudlog_erase(BlueSkyCloudLog *log);
+void bluesky_cloudlog_stats_update(BlueSkyCloudLog *log, int type);
+void bluesky_cloudlog_sync(BlueSkyCloudLog *log);
+void bluesky_cloudlog_insert(BlueSkyCloudLog *log);
+void bluesky_cloudlog_insert_locked(BlueSkyCloudLog *log);
+BlueSkyCloudLog *bluesky_cloudlog_get(BlueSkyFS *fs, BlueSkyCloudID id);
+void bluesky_cloudlog_prefetch(BlueSkyCloudLog *log);
+void bluesky_cloudlog_fetch(BlueSkyCloudLog *log);
+BlueSkyCloudPointer bluesky_cloudlog_serialize(BlueSkyCloudLog *log,
+ BlueSkyFS *fs);
+void bluesky_cloudlog_flush(BlueSkyFS *fs);
+
+/* Logging infrastructure for ensuring operations are persistently recorded to
+ * disk. */
+#define BLUESKY_CRC32C_SEED (~(uint32_t)0)
+#define BLUESKY_CRC32C_VALIDATOR ((uint32_t)0xb798b438UL)
+uint32_t crc32c(uint32_t crc, const char *buf, unsigned int length);
+uint32_t crc32c_finalize(uint32_t crc);
+
+struct BlueSkyLog {
+ BlueSkyFS *fs;
+ char *log_directory;
+ GAsyncQueue *queue;
+ int fd, dirfd;
+ int seq_num;
+ GSList *committed;
+
+ /* The currently-open log file. */
+ BlueSkyCacheFile *current_log;
+
+ /* Cache of log segments which have been memory-mapped. */
+ GMutex *mmap_lock;
+ GHashTable *mmap_cache;
+
+ /* A count of the disk space consumed (in 1024-byte units) by all files
+ * tracked by mmap_cache (whether mapped or not, actually). */
+ gint disk_used;
+
+ /* The smallest journal sequence number which may still contain data that
+ * must be preserved (since it it not yet in the cloud). */
+ int journal_watermark;
+};
+
+/* An object for tracking log files which are stored locally--either the
+ * journal for filesystem consistency or log segments which have been fetched
+ * back from cloud storage. */
+struct BlueSkyCacheFile {
+ GMutex *lock;
+ GCond *cond;
+ gint refcount;
+ int type; // Only one of CLOUDLOG_{JOURNAL,CLOUD}
+ int log_dir;
+ int log_seq;
+ char *filename; // Local filename, relateive to log directory
+ gint mapcount; // References to the mmaped data
+ const char *addr; // May be null if data is not mapped in memory
+ size_t len;
+ int disk_used;
+ BlueSkyFS *fs;
+ BlueSkyLog *log;
+ gboolean fetching, ready; // Cloud data: downloading or ready for use
+ int64_t atime; // Access time, for cache management
+ BlueSkyRangeset *items; // Locations of valid items
+ BlueSkyRangeset *prefetches;// Locations we have been requested to prefetch
+};
+
+BlueSkyLog *bluesky_log_new(const char *log_directory);
+void bluesky_log_item_submit(BlueSkyCloudLog *item, BlueSkyLog *log);
+void bluesky_log_finish_all(GList *log_items);
+BlueSkyCloudLog *bluesky_log_get_commit_point(BlueSkyFS *fs);
+void bluesky_log_write_commit_point(BlueSkyFS *fs, BlueSkyCloudLog *marker);
+
+BlueSkyRCStr *bluesky_log_map_object(BlueSkyCloudLog *item, gboolean map_data);
+void bluesky_mmap_unref(BlueSkyCacheFile *mmap);
+void bluesky_cachefile_unref(BlueSkyCacheFile *cachefile);
+
+BlueSkyCacheFile *bluesky_cachefile_lookup(BlueSkyFS *fs,
+ int clouddir, int log_seq,
+ gboolean start_fetch);
+void bluesky_cachefile_gc(BlueSkyFS *fs);
+
+void bluesky_replay(BlueSkyFS *fs);
+
+/* Used to track log segments that are being written to the cloud. */
+typedef struct {
+ BlueSkyRCStr *data;
+ GSList *items;
+ GMutex *lock;
+ GCond *cond;
+ gboolean complete;
+} SerializedRecord;
+
+/***** Inode map management *****/
+
+/* Mapping information for a single inode number. These are grouped together
+ * into InodeMapRange objects. */
+typedef struct {
+ uint64_t inum;
+
+ /* A pointer to the cloud log entry for this inode. This may or may not
+ * actually have data loaded (it might just contain pointers to the data
+ * location, and in fact this will likely often be the case). */
+ BlueSkyCloudLog *item;
+} InodeMapEntry;
+
+typedef struct {
+ /* Starting and ending inode number values that fall in this section.
+ * Endpoint values are inclusive. */
+ uint64_t start, end;
+
+ /* A sorted list (by inode number) of InodeMapEntry objects. */
+ GSequence *map_entries;
+
+ /* The serialized version of the inode map data. */
+ BlueSkyCloudLog *serialized;
+
+ /* Have there been changes that require writing this section out again? */
+ gboolean dirty;
+} InodeMapRange;
+
+InodeMapEntry *bluesky_inode_map_lookup(GSequence *inode_map, uint64_t inum,
+ int action);
+BlueSkyCloudLog *bluesky_inode_map_serialize(BlueSkyFS *fs);
+void bluesky_inode_map_minimize(BlueSkyFS *fs);
+
+gboolean bluesky_checkpoint_load(BlueSkyFS *fs);
+