X-Git-Url: http://git.vrable.net/?p=bluesky.git;a=blobdiff_plain;f=bluesky%2Flog.c;h=ccc9a7a712bafc698ae17dfcc87cff6b50f2e2e9;hp=a904fe1beff88f44f78133a48a9a2a4aa6b8edf6;hb=b52abd849493636b81dda8c752a60834f1a6b91f;hpb=ef355dcfecf0dad2d95ff5fb3d847f1bf8b9ebe5 diff --git a/bluesky/log.c b/bluesky/log.c index a904fe1..ccc9a7a 100644 --- a/bluesky/log.c +++ b/bluesky/log.c @@ -34,28 +34,24 @@ * only incompletely written out before a crash, which should only happen for * log records that were not considered committed). */ -// Rough size limit for a log segment. This is not a firm limit and there are -// no absolute guarantees on the size of a log segment. -#define LOG_SEGMENT_SIZE (1 << 22) - -// Target amount of disk space to use for the journal and cache files, in -// kilobytes. -#define DISK_CACHE_SIZE_TARGET (64 * 1024) - #define HEADER_MAGIC 0x676f4c0a #define FOOTER_MAGIC 0x2e435243 -struct log_header { - uint32_t magic; // HEADER_MAGIC - uint64_t offset; // Starting byte offset of the log header - uint32_t size; // Size of the data item (bytes) - 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)); +static size_t readbuf(int fd, char *buf, size_t len) +{ + size_t total_bytes = 0; + while (len > 0) { + ssize_t bytes = read(fd, buf, len); + if (bytes < 0 && errno == EINTR) + continue; + g_assert(bytes >= 0); + if (bytes == 0) + break; + buf += bytes; + len -= bytes; + } + return total_bytes; +} static void writebuf(int fd, const char *buf, size_t len) { @@ -78,12 +74,23 @@ static void log_commit(BlueSkyLog *log) return; fdatasync(log->fd); + + /* Update disk-space usage statistics for the journal file. */ + g_atomic_int_add(&log->disk_used, -log->current_log->disk_used); + struct stat statbuf; + if (fstat(log->fd, &statbuf) >= 0) { + /* Convert from 512-byte blocks to 1-kB units */ + log->current_log->disk_used = (statbuf.st_blocks + 1) / 2; + } + g_atomic_int_add(&log->disk_used, log->current_log->disk_used); + while (log->committed != NULL) { BlueSkyCloudLog *item = (BlueSkyCloudLog *)log->committed->data; g_mutex_lock(item->lock); bluesky_cloudlog_stats_update(item, -1); item->pending_write &= ~CLOUDLOG_JOURNAL; - item->location_flags |= CLOUDLOG_JOURNAL; + item->location_flags + = (item->location_flags & ~CLOUDLOG_UNCOMMITTED) | CLOUDLOG_JOURNAL; bluesky_cloudlog_stats_update(item, 1); g_cond_signal(item->cond); g_mutex_unlock(item->lock); @@ -125,7 +132,8 @@ static gboolean log_open(BlueSkyLog *log) } } - log->current_log = bluesky_cachefile_lookup(log->fs, -1, log->seq_num); + log->current_log = bluesky_cachefile_lookup(log->fs, -1, log->seq_num, + FALSE); g_assert(log->current_log != NULL); g_mutex_unlock(log->current_log->lock); @@ -177,9 +185,15 @@ static gpointer log_thread(gpointer d) item->pending_write |= CLOUDLOG_JOURNAL; bluesky_cloudlog_stats_update(item, 1); + GString *data1 = g_string_new(""); + GString *data2 = g_string_new(""); + GString *data3 = g_string_new(""); + bluesky_serialize_cloudlog(item, data1, data2, data3); + struct log_header header; struct log_footer footer; - size_t size = sizeof(header) + sizeof(footer) + item->data->len; + size_t size = sizeof(header) + sizeof(footer); + size += data1->len + data2->len + data3->len; off_t offset = 0; if (log->fd >= 0) offset = lseek(log->fd, 0, SEEK_CUR); @@ -193,9 +207,13 @@ static gpointer log_thread(gpointer d) } header.magic = GUINT32_TO_LE(HEADER_MAGIC); - header.offset = GUINT64_TO_LE(offset); - header.size = GUINT32_TO_LE(item->data->len); + header.offset = GUINT32_TO_LE(offset); + header.size1 = GUINT32_TO_LE(data1->len); + header.size2 = GUINT32_TO_LE(data2->len); + header.size3 = GUINT32_TO_LE(data3->len); + header.type = item->type + '0'; header.id = item->id; + header.inum = GUINT64_TO_LE(item->inum); footer.magic = GUINT32_TO_LE(FOOTER_MAGIC); uint32_t crc = BLUESKY_CRC32C_SEED; @@ -203,8 +221,12 @@ static gpointer log_thread(gpointer d) writebuf(log->fd, (const char *)&header, sizeof(header)); crc = crc32c(crc, (const char *)&header, sizeof(header)); - writebuf(log->fd, item->data->data, item->data->len); - crc = crc32c(crc, item->data->data, item->data->len); + writebuf(log->fd, data1->str, data1->len); + crc = crc32c(crc, data1->str, data1->len); + writebuf(log->fd, data2->str, data2->len); + crc = crc32c(crc, data2->str, data2->len); + writebuf(log->fd, data3->str, data3->len); + crc = crc32c(crc, data3->str, data3->len); crc = crc32c(crc, (const char *)&footer, sizeof(footer) - sizeof(uint32_t)); @@ -212,19 +234,15 @@ static gpointer log_thread(gpointer d) writebuf(log->fd, (const char *)&footer, sizeof(footer)); item->log_seq = log->seq_num; - item->log_offset = offset + sizeof(header); - item->log_size = item->data->len; - - offset += sizeof(header) + sizeof(footer) + item->data->len; - - /* Since we have just written a new dirty object to the journal, - * increment the count of live dirty objects in that journal file. The - * count will be decremented when objects are deleted or written to the - * cloud. */ - if (!(item->location_flags & CLOUDLOG_CLOUD)) { - g_atomic_int_add(&log->current_log->dirty_refs, 1); - item->dirty_journal = log->current_log; - } + item->log_offset = offset; + item->log_size = size; + item->data_size = item->data->len; + + offset += size; + + g_string_free(data1, TRUE); + g_string_free(data2, TRUE); + g_string_free(data3, TRUE); /* Replace the log item's string data with a memory-mapped copy of the * data, now that it has been written to the log file. (Even if it @@ -234,7 +252,7 @@ static gpointer log_thread(gpointer d) item->data = NULL; bluesky_cloudlog_fetch(item); - log->committed = g_slist_prepend(log->committed, item); + log->committed = g_slist_prepend(log->committed, item); g_atomic_int_add(&item->data_lock_count, -1); g_mutex_unlock(item->lock); @@ -258,6 +276,20 @@ BlueSkyLog *bluesky_log_new(const char *log_directory) log->mmap_lock = g_mutex_new(); log->mmap_cache = g_hash_table_new(g_str_hash, g_str_equal); + /* Determine the highest-numbered log file, so that we can start writing + * out new journal entries at the next sequence number. */ + GDir *dir = g_dir_open(log_directory, 0, NULL); + if (dir != NULL) { + const gchar *file; + while ((file = g_dir_read_name(dir)) != NULL) { + if (strncmp(file, "journal-", 8) == 0) { + log->seq_num = MAX(log->seq_num, atoi(&file[8]) + 1); + } + } + g_dir_close(dir); + g_print("Starting journal at sequence number %d\n", log->seq_num); + } + log->dirfd = open(log->log_directory, O_DIRECTORY); if (log->dirfd < 0) { fprintf(stderr, "Unable to open logging directory: %m\n"); @@ -271,9 +303,12 @@ BlueSkyLog *bluesky_log_new(const char *log_directory) void bluesky_log_item_submit(BlueSkyCloudLog *item, BlueSkyLog *log) { - bluesky_cloudlog_ref(item); - g_atomic_int_add(&item->data_lock_count, 1); - g_async_queue_push(log->queue, item); + if (!(item->location_flags & CLOUDLOG_JOURNAL)) { + bluesky_cloudlog_ref(item); + item->location_flags |= CLOUDLOG_UNCOMMITTED; + g_atomic_int_add(&item->data_lock_count, 1); + g_async_queue_push(log->queue, item); + } } void bluesky_log_finish_all(GList *log_items) @@ -282,7 +317,7 @@ void bluesky_log_finish_all(GList *log_items) BlueSkyCloudLog *item = (BlueSkyCloudLog *)log_items->data; g_mutex_lock(item->lock); - while ((item->pending_write & CLOUDLOG_JOURNAL)) + while ((item->location_flags & CLOUDLOG_UNCOMMITTED)) g_cond_wait(item->cond, item->lock); g_mutex_unlock(item->lock); bluesky_cloudlog_unref(item); @@ -291,6 +326,48 @@ void bluesky_log_finish_all(GList *log_items) } } +/* Return a committed cloud log record that can be used as a watermark for how + * much of the journal has been written. */ +BlueSkyCloudLog *bluesky_log_get_commit_point(BlueSkyFS *fs) +{ + BlueSkyCloudLog *marker = bluesky_cloudlog_new(fs, NULL); + marker->type = LOGTYPE_JOURNAL_MARKER; + marker->data = bluesky_string_new(g_strdup(""), 0); + bluesky_cloudlog_stats_update(marker, 1); + bluesky_cloudlog_sync(marker); + + g_mutex_lock(marker->lock); + while ((marker->pending_write & CLOUDLOG_JOURNAL)) + g_cond_wait(marker->cond, marker->lock); + g_mutex_unlock(marker->lock); + + return marker; +} + +void bluesky_log_write_commit_point(BlueSkyFS *fs, BlueSkyCloudLog *marker) +{ + BlueSkyCloudLog *commit = bluesky_cloudlog_new(fs, NULL); + commit->type = LOGTYPE_JOURNAL_CHECKPOINT; + + uint32_t seq, offset; + seq = GUINT32_TO_LE(marker->log_seq); + offset = GUINT32_TO_LE(marker->log_offset); + GString *loc = g_string_new(""); + g_string_append_len(loc, (const gchar *)&seq, sizeof(seq)); + g_string_append_len(loc, (const gchar *)&offset, sizeof(offset)); + commit->data = bluesky_string_new_from_gstring(loc); + bluesky_cloudlog_stats_update(commit, 1); + bluesky_cloudlog_sync(commit); + + g_mutex_lock(commit->lock); + while ((commit->location_flags & CLOUDLOG_UNCOMMITTED)) + g_cond_wait(commit->cond, commit->lock); + g_mutex_unlock(commit->lock); + + bluesky_cloudlog_unref(marker); + bluesky_cloudlog_unref(commit); +} + /* Memory-map the given log object into memory (read-only) and return a pointer * to it. */ static int page_size = 0; @@ -300,56 +377,13 @@ void bluesky_cachefile_unref(BlueSkyCacheFile *cachefile) g_atomic_int_add(&cachefile->refcount, -1); } -static void cloudlog_fetch_complete(BlueSkyStoreAsync *async, - BlueSkyCacheFile *cachefile); - -static void cloudlog_fetch_start(BlueSkyCacheFile *cachefile) -{ - g_atomic_int_inc(&cachefile->refcount); - cachefile->fetching = TRUE; - g_print("Starting fetch of %s from cloud\n", cachefile->filename); - BlueSkyStoreAsync *async = bluesky_store_async_new(cachefile->fs->store); - async->op = STORE_OP_GET; - async->key = g_strdup(cachefile->filename); - bluesky_store_async_add_notifier(async, - (GFunc)cloudlog_fetch_complete, - cachefile); - bluesky_store_async_submit(async); - bluesky_store_async_unref(async); -} - -static void cloudlog_fetch_complete(BlueSkyStoreAsync *async, - BlueSkyCacheFile *cachefile) -{ - g_print("Fetch of %s from cloud complete, status = %d\n", - async->key, async->result); - - g_mutex_lock(cachefile->lock); - if (async->result >= 0) { - char *pathname = g_strdup_printf("%s/%s", - cachefile->log->log_directory, - cachefile->filename); - if (!g_file_set_contents(pathname, async->data->data, async->data->len, - NULL)) - g_print("Error writing out fetched file to cache!\n"); - g_free(pathname); - - cachefile->fetching = FALSE; - cachefile->ready = TRUE; - } else { - g_print("Error fetching from cloud, retrying...\n"); - cloudlog_fetch_start(cachefile); - } - - bluesky_cachefile_unref(cachefile); - g_cond_broadcast(cachefile->cond); - g_mutex_unlock(cachefile->lock); -} +static void cloudlog_fetch_start(BlueSkyCacheFile *cachefile); /* Find the BlueSkyCacheFile object for the given journal or cloud log segment. * Returns the object in the locked state and with a reference taken. */ BlueSkyCacheFile *bluesky_cachefile_lookup(BlueSkyFS *fs, - int clouddir, int log_seq) + int clouddir, int log_seq, + gboolean start_fetch) { if (page_size == 0) { page_size = getpagesize(); @@ -380,7 +414,8 @@ BlueSkyCacheFile *bluesky_cachefile_lookup(BlueSkyFS *fs, /* A stale reference to a journal file which doesn't exist any longer * because it was reclaimed. Return NULL. */ } else if (map == NULL) { - g_print("Adding cache file %s\n", logname); + if (bluesky_verbose) + g_print("Adding cache file %s\n", logname); map = g_new0(BlueSkyCacheFile, 1); map->fs = fs; @@ -390,75 +425,323 @@ BlueSkyCacheFile *bluesky_cachefile_lookup(BlueSkyFS *fs, g_mutex_lock(map->lock); map->cond = g_cond_new(); map->filename = g_strdup(logname); + map->log_dir = clouddir; map->log_seq = log_seq; map->log = log; g_atomic_int_set(&map->mapcount, 0); g_atomic_int_set(&map->refcount, 0); + map->items = bluesky_rangeset_new(); g_hash_table_insert(log->mmap_cache, map->filename, map); - // If the log file is stored in the cloud, we may need to fetch it - if (clouddir >= 0) - cloudlog_fetch_start(map); + int fd = openat(log->dirfd, logname, O_WRONLY | O_CREAT, 0600); + if (fd >= 0) { + ftruncate(fd, 5 << 20); // FIXME + close(fd); + } } else { g_mutex_lock(map->lock); } + + /* If the log file is stored in the cloud and has not been fully fetched, + * we may need to initiate a fetch now. */ + if (clouddir >= 0 && start_fetch && !map->complete && !map->fetching) + cloudlog_fetch_start(map); + g_mutex_unlock(log->mmap_lock); if (map != NULL) g_atomic_int_inc(&map->refcount); return map; } -BlueSkyRCStr *bluesky_log_map_object(BlueSkyFS *fs, int log_dir, - int log_seq, int log_offset, int log_size) +static void robust_pwrite(int fd, const char *buf, ssize_t count, off_t offset) { - if (page_size == 0) { - page_size = getpagesize(); + while (count > 0) { + ssize_t written = pwrite(fd, buf, count, offset); + if (written < 0) { + if (errno == EINTR) + continue; + g_warning("pwrite failure: %m"); + return; + } + buf += written; + count -= written; + offset += written; } +} - BlueSkyLog *log = fs->log; - BlueSkyCacheFile *map = bluesky_cachefile_lookup(fs, log_dir, log_seq); +static void cloudlog_partial_fetch_complete(BlueSkyStoreAsync *async, + BlueSkyCacheFile *cachefile); - if (map == NULL) { - return NULL; - } +static void cloudlog_partial_fetch_start(BlueSkyCacheFile *cachefile, + size_t offset, size_t length) +{ + g_atomic_int_inc(&cachefile->refcount); + if (bluesky_verbose) + g_print("Starting partial fetch of %s from cloud (%zd + %zd)\n", + cachefile->filename, offset, length); + BlueSkyStoreAsync *async = bluesky_store_async_new(cachefile->fs->store); + async->op = STORE_OP_GET; + async->key = g_strdup(cachefile->filename); + async->start = offset; + async->len = length; + async->profile = bluesky_profile_get(); + bluesky_store_async_add_notifier(async, + (GFunc)cloudlog_partial_fetch_complete, + cachefile); + bluesky_store_async_submit(async); + bluesky_store_async_unref(async); +} - if (map->addr == NULL) { - while (!map->ready && map->fetching) { - g_print("Waiting for log segment to be fetched from cloud...\n"); - g_cond_wait(map->cond, map->lock); - } +static void cloudlog_partial_fetch_complete(BlueSkyStoreAsync *async, + BlueSkyCacheFile *cachefile) +{ + if (bluesky_verbose || async->result != 0) + g_print("Fetch of %s from cloud complete, status = %d\n", + async->key, async->result); - int fd = openat(log->dirfd, map->filename, O_RDONLY); + g_mutex_lock(cachefile->lock); + if (async->result >= 0) { + if (async->len == 0) { + if (bluesky_verbose) + g_print("Complete object was fetched.\n"); + cachefile->complete = TRUE; + } - if (fd < 0) { - fprintf(stderr, "Error opening logfile %s: %m\n", map->filename); - bluesky_cachefile_unref(map); - g_mutex_unlock(map->lock); - return NULL; + /* Descrypt items fetched and write valid items out to the local log, + * but only if they do not overlap existing objects. This will protect + * against an attack by the cloud provider where one valid object is + * moved to another offset and used to overwrite data that we already + * have fetched. */ + BlueSkyRangeset *items = bluesky_rangeset_new(); + int fd = openat(cachefile->log->dirfd, cachefile->filename, O_WRONLY); + if (fd >= 0) { + gboolean allow_unauth; + async->data = bluesky_string_dup(async->data); + allow_unauth = cachefile->log_dir == BLUESKY_CLOUD_DIR_CLEANER; + bluesky_cloudlog_decrypt(async->data->data, async->data->len, + cachefile->fs->keys, items, allow_unauth); + uint64_t item_offset = 0; + while (TRUE) { + const BlueSkyRangesetItem *item; + item = bluesky_rangeset_lookup_next(items, item_offset); + if (item == NULL) + break; + if (bluesky_verbose) { + g_print(" item offset from range request: %d\n", + (int)(item->start + async->start)); + } + if (bluesky_rangeset_insert(cachefile->items, + async->start + item->start, + item->length, item->data)) + { + robust_pwrite(fd, async->data->data + item->start, + item->length, async->start + item->start); + } else { + g_print(" item overlaps existing data!\n"); + } + item_offset = item->start + 1; + } + /* TODO: Iterate over items and merge into cached file. */ + close(fd); + } else { + g_warning("Unable to open and write to cache file %s: %m", + cachefile->filename); } - off_t length = lseek(fd, 0, SEEK_END); - map->addr = (const char *)mmap(NULL, length, PROT_READ, MAP_SHARED, - fd, 0); - g_atomic_int_add(&log->disk_used, -(map->len / 1024)); - map->len = length; - g_atomic_int_add(&log->disk_used, map->len / 1024); + bluesky_rangeset_free(items); + } else { + g_print("Error fetching %s from cloud, retrying...\n", async->key); + cloudlog_partial_fetch_start(cachefile, async->start, async->len); + } - g_print("Re-mapped log segment %d...\n", log_seq); - g_atomic_int_inc(&map->refcount); + /* Update disk-space usage statistics, since the writes above may have + * consumed more space. */ + g_atomic_int_add(&cachefile->log->disk_used, -cachefile->disk_used); + struct stat statbuf; + if (fstatat(cachefile->log->dirfd, cachefile->filename, &statbuf, 0) >= 0) { + /* Convert from 512-byte blocks to 1-kB units */ + cachefile->disk_used = (statbuf.st_blocks + 1) / 2; + } + g_atomic_int_add(&cachefile->log->disk_used, cachefile->disk_used); + + bluesky_cachefile_unref(cachefile); + g_cond_broadcast(cachefile->cond); + g_mutex_unlock(cachefile->lock); +} +static void cloudlog_fetch_start(BlueSkyCacheFile *cachefile) +{ + g_atomic_int_inc(&cachefile->refcount); + cachefile->fetching = TRUE; + if (bluesky_verbose) + g_print("Starting fetch of %s from cloud\n", cachefile->filename); + BlueSkyStoreAsync *async = bluesky_store_async_new(cachefile->fs->store); + async->op = STORE_OP_GET; + async->key = g_strdup(cachefile->filename); + async->profile = bluesky_profile_get(); + bluesky_store_async_add_notifier(async, + (GFunc)cloudlog_partial_fetch_complete, + cachefile); + bluesky_store_async_submit(async); + bluesky_store_async_unref(async); +} + +/* Map and return a read-only version of a byte range from a cached file. The + * CacheFile object must be locked. */ +BlueSkyRCStr *bluesky_cachefile_map_raw(BlueSkyCacheFile *cachefile, + off_t offset, size_t size) +{ + cachefile->atime = bluesky_get_current_time(); + + /* Easy case: the needed data is already in memory */ + if (cachefile->addr != NULL && offset + size <= cachefile->len) + return bluesky_string_new_from_mmap(cachefile, offset, size); + + int fd = openat(cachefile->log->dirfd, cachefile->filename, O_RDONLY); + if (fd < 0) { + fprintf(stderr, "Error opening logfile %s: %m\n", + cachefile->filename); + return NULL; + } + + off_t length = lseek(fd, 0, SEEK_END); + if (offset + size > length) { close(fd); + return NULL; } - g_mutex_unlock(log->mmap_lock); + /* File is not mapped in memory. Map the entire file in, then return a + * pointer to just the required data. */ + if (cachefile->addr == NULL) { + cachefile->addr = (const char *)mmap(NULL, length, PROT_READ, + MAP_SHARED, fd, 0); + cachefile->len = length; + g_atomic_int_inc(&cachefile->refcount); + + close(fd); + return bluesky_string_new_from_mmap(cachefile, offset, size); + } + + /* Otherwise, the file was mapped in but doesn't cover the data we need. + * This shouldn't happen much, if at all, but if it does just read the data + * we need directly from the file. We lose memory-management benefits of + * using mmapped data, but otherwise this works. */ + char *buf = g_malloc(size); + size_t actual_size = readbuf(fd, buf, size); + close(fd); + if (actual_size != size) { + g_free(buf); + return NULL; + } else { + return bluesky_string_new(buf, size); + } +} + +/* The arguments are mostly straightforward. log_dir is -1 for access from the + * journal, and non-negative for access to a cloud log segment. map_data + * should be TRUE for the case that are mapping just the data of an item where + * we have already parsed the item headers; this surpresses the error when the + * access is not to the first bytes of the item. */ +BlueSkyRCStr *bluesky_log_map_object(BlueSkyCloudLog *item, gboolean map_data) +{ + BlueSkyFS *fs = item->fs; + BlueSkyCacheFile *map = NULL; + BlueSkyRCStr *str = NULL; + int location = 0; + size_t file_offset = 0, file_size = 0; + gboolean range_request = bluesky_options.full_segment_fetches + ? FALSE : TRUE; + + if (page_size == 0) { + page_size = getpagesize(); + } + + bluesky_cloudlog_stats_update(item, -1); + + /* First, check to see if the journal still contains a copy of the item and + * if so use that. */ + if ((item->location_flags | item->pending_write) & CLOUDLOG_JOURNAL) { + map = bluesky_cachefile_lookup(fs, -1, item->log_seq, TRUE); + if (map != NULL) { + location = CLOUDLOG_JOURNAL; + file_offset = item->log_offset; + file_size = item->log_size; + } + } + + if (location == 0 && (item->location_flags & CLOUDLOG_CLOUD)) { + item->location_flags &= ~CLOUDLOG_JOURNAL; + map = bluesky_cachefile_lookup(fs, + item->location.directory, + item->location.sequence, + !range_request); + if (map == NULL) { + g_warning("Unable to remap cloud log segment!"); + goto exit1; + } + location = CLOUDLOG_CLOUD; + file_offset = item->location.offset; + file_size = item->location.size; + } + + /* Log segments fetched from the cloud might only be partially-fetched. + * Check whether the object we are interested in is available. */ + if (location == CLOUDLOG_CLOUD) { + while (TRUE) { + const BlueSkyRangesetItem *rangeitem; + rangeitem = bluesky_rangeset_lookup(map->items, file_offset); + if (rangeitem != NULL && (rangeitem->start != file_offset + || rangeitem->length != file_size)) { + g_warning("log-%d: Item offset %zd seems to be invalid!", + (int)item->location.sequence, file_offset); + goto exit2; + } + if (rangeitem == NULL) { + if (bluesky_verbose) { + g_print("Item at offset 0x%zx not available, need to fetch.\n", + file_offset); + } + if (range_request) { + uint64_t start = file_offset, length = file_size, end; + if (map->prefetches != NULL) + bluesky_rangeset_get_extents(map->prefetches, + &start, &length); + start = MIN(start, file_offset); + end = MAX(start + length, file_offset + file_size); + length = end - start; + cloudlog_partial_fetch_start(map, start, length); + if (map->prefetches != NULL) { + bluesky_rangeset_free(map->prefetches); + map->prefetches = NULL; + } + } + g_cond_wait(map->cond, map->lock); + } else if (rangeitem->start == file_offset + && rangeitem->length == file_size) { + if (bluesky_verbose) + g_print("Item %zd now available.\n", file_offset); + break; + } + } + } + + if (map_data) { + if (location == CLOUDLOG_JOURNAL) + file_offset += sizeof(struct log_header); + else + file_offset += sizeof(struct cloudlog_header); - BlueSkyRCStr *str; - map->atime = bluesky_get_current_time(); - str = bluesky_string_new_from_mmap(map, log_offset, log_size); + file_size = item->data_size; + } + str = bluesky_cachefile_map_raw(map, file_offset, file_size); + +exit2: bluesky_cachefile_unref(map); g_mutex_unlock(map->lock); +exit1: + bluesky_cloudlog_stats_update(item, 1); return str; } @@ -469,91 +752,279 @@ void bluesky_mmap_unref(BlueSkyCacheFile *mmap) if (g_atomic_int_dec_and_test(&mmap->mapcount)) { g_mutex_lock(mmap->lock); - if (g_atomic_int_get(&mmap->mapcount) == 0) { - g_print("Unmapped log segment %d...\n", mmap->log_seq); + if (mmap->addr != NULL && g_atomic_int_get(&mmap->mapcount) == 0) { + if (bluesky_verbose) + g_print("Unmapped log segment %d...\n", mmap->log_seq); munmap((void *)mmap->addr, mmap->len); mmap->addr = NULL; g_atomic_int_add(&mmap->refcount, -1); } g_mutex_unlock(mmap->lock); } + g_assert(g_atomic_int_get(&mmap->mapcount) >= 0); } -/* Scan through all currently-stored files in the journal/cache and garbage - * collect old unused ones, if needed. */ -static void gather_cachefiles(gpointer key, gpointer value, gpointer user_data) +/******************************* JOURNAL REPLAY ******************************* + * The journal replay code is used to recover filesystem state after a + * filesystem restart. We first look for the most recent commit record in the + * journal, which indicates the point before which all data in the journal has + * also been committed to the cloud. Then, we read in all data in the log past + * that point. + */ +static GList *directory_contents(const char *dirname) { - GList **files = (GList **)user_data; - *files = g_list_prepend(*files, value); + GList *contents = NULL; + GDir *dir = g_dir_open(dirname, 0, NULL); + if (dir == NULL) { + g_warning("Unable to open journal directory: %s", dirname); + return NULL; + } + + const gchar *file; + while ((file = g_dir_read_name(dir)) != NULL) { + if (strncmp(file, "journal-", 8) == 0) + contents = g_list_prepend(contents, g_strdup(file)); + } + g_dir_close(dir); + + contents = g_list_sort(contents, (GCompareFunc)strcmp); + + return contents; } -static gint compare_cachefiles(gconstpointer a, gconstpointer b) +static gboolean validate_journal_item(const char *buf, size_t len, off_t offset) { - int64_t ta, tb; - - ta = ((BlueSkyCacheFile *)a)->atime; - tb = ((BlueSkyCacheFile *)b)->atime; - if (ta < tb) - return -1; - else if (ta > tb) - return 1; - else - return 0; + const struct log_header *header; + const struct log_footer *footer; + + if (offset + sizeof(struct log_header) + sizeof(struct log_footer) > len) + return FALSE; + + header = (const struct log_header *)(buf + offset); + if (GUINT32_FROM_LE(header->magic) != HEADER_MAGIC) + return FALSE; + if (GUINT32_FROM_LE(header->offset) != offset) + return FALSE; + size_t size = GUINT32_FROM_LE(header->size1) + + GUINT32_FROM_LE(header->size2) + + GUINT32_FROM_LE(header->size3); + + off_t footer_offset = offset + sizeof(struct log_header) + size; + if (footer_offset + sizeof(struct log_footer) > len) + return FALSE; + footer = (const struct log_footer *)(buf + footer_offset); + + if (GUINT32_FROM_LE(footer->magic) != FOOTER_MAGIC) + return FALSE; + + uint32_t crc = crc32c(BLUESKY_CRC32C_SEED, buf + offset, + sizeof(struct log_header) + sizeof(struct log_footer) + + size); + if (crc != BLUESKY_CRC32C_VALIDATOR) { + g_warning("Journal entry failed to validate: CRC %08x != %08x", + crc, BLUESKY_CRC32C_VALIDATOR); + return FALSE; + } + + return TRUE; } -void bluesky_cachefile_gc(BlueSkyFS *fs) +/* Scan through a journal segment to extract correctly-written items (those + * that pass sanity checks and have a valid checksum). */ +static void bluesky_replay_scan_journal(const char *buf, size_t len, + uint32_t *seq, uint32_t *start_offset) { - GList *files = NULL; - - g_mutex_lock(fs->log->mmap_lock); - g_hash_table_foreach(fs->log->mmap_cache, gather_cachefiles, &files); - - /* Sort based on atime. The atime should be stable since it shouln't be - * updated except by threads which can grab the mmap_lock, which we already - * hold. */ - files = g_list_sort(files, compare_cachefiles); - - /* Walk the list of files, starting with the oldest, deleting files if - * possible until enough space has been reclaimed. */ - g_print("\nScanning cache: (total size = %d kB)\n", fs->log->disk_used); - while (files != NULL) { - BlueSkyCacheFile *cachefile = (BlueSkyCacheFile *)files->data; - /* Try to lock the structure, but if the lock is held by another thread - * then we'll just skip the file on this pass. */ - if (g_mutex_trylock(cachefile->lock)) { - int64_t age = bluesky_get_current_time() - cachefile->atime; - g_print("%s addr=%p mapcount=%d refcount=%d dirty=%d atime_age=%f", - cachefile->filename, cachefile->addr, cachefile->mapcount, - cachefile->refcount, cachefile->dirty_refs, age / 1e6); - if (cachefile->fetching) - g_print(" (fetching)"); - g_print("\n"); - - if (g_atomic_int_get(&fs->log->disk_used) > DISK_CACHE_SIZE_TARGET - && g_atomic_int_get(&cachefile->refcount) == 0 - && g_atomic_int_get(&cachefile->mapcount) == 0 - && g_atomic_int_get(&cachefile->dirty_refs) == 0) - { - g_print(" ...deleting\n"); - if (unlinkat(fs->log->dirfd, cachefile->filename, 0) < 0) { - fprintf(stderr, "Unable to unlink journal %s: %m\n", - cachefile->filename); - } + const struct log_header *header; + off_t offset = 0; + + while (validate_journal_item(buf, len, offset)) { + header = (const struct log_header *)(buf + offset); + size_t size = GUINT32_FROM_LE(header->size1) + + GUINT32_FROM_LE(header->size2) + + GUINT32_FROM_LE(header->size3); + + if (header->type - '0' == LOGTYPE_JOURNAL_CHECKPOINT) { + const uint32_t *data = (const uint32_t *)((const char *)header + sizeof(struct log_header)); + *seq = GUINT32_FROM_LE(data[0]); + *start_offset = GUINT32_FROM_LE(data[1]); + } + + offset += sizeof(struct log_header) + size + sizeof(struct log_footer); + } +} - g_atomic_int_add(&fs->log->disk_used, -(cachefile->len / 1024)); - g_hash_table_remove(fs->log->mmap_cache, cachefile->filename); - g_mutex_unlock(cachefile->lock); - g_mutex_free(cachefile->lock); - g_cond_free(cachefile->cond); - g_free(cachefile->filename); - g_free(cachefile); - } else { - g_mutex_unlock(cachefile->lock); +static void reload_item(BlueSkyCloudLog *log_item, + const char *data, + size_t len1, size_t len2, size_t len3) +{ + BlueSkyFS *fs = log_item->fs; + /*const char *data1 = data;*/ + const BlueSkyCloudID *data2 + = (const BlueSkyCloudID *)(data + len1); + /*const BlueSkyCloudPointer *data3 + = (const BlueSkyCloudPointer *)(data + len1 + len2);*/ + + bluesky_cloudlog_stats_update(log_item, -1); + bluesky_string_unref(log_item->data); + log_item->data = NULL; + log_item->location_flags = CLOUDLOG_JOURNAL; + bluesky_cloudlog_stats_update(log_item, 1); + + BlueSkyCloudID id0; + memset(&id0, 0, sizeof(id0)); + + int link_count = len2 / sizeof(BlueSkyCloudID); + GArray *new_links = g_array_new(FALSE, TRUE, sizeof(BlueSkyCloudLog *)); + for (int i = 0; i < link_count; i++) { + BlueSkyCloudID id = data2[i]; + BlueSkyCloudLog *ref = NULL; + if (memcmp(&id, &id0, sizeof(BlueSkyCloudID)) != 0) { + g_mutex_lock(fs->lock); + ref = g_hash_table_lookup(fs->locations, &id); + if (ref != NULL) { + bluesky_cloudlog_ref(ref); } + g_mutex_unlock(fs->lock); + } + g_array_append_val(new_links, ref); + } + + for (int i = 0; i < log_item->links->len; i++) { + BlueSkyCloudLog *c = g_array_index(log_item->links, + BlueSkyCloudLog *, i); + bluesky_cloudlog_unref(c); + } + g_array_unref(log_item->links); + log_item->links = new_links; +} + +static void bluesky_replay_scan_journal2(BlueSkyFS *fs, GList **objects, + int log_seq, int start_offset, + const char *buf, size_t len) +{ + const struct log_header *header; + off_t offset = start_offset; + + while (validate_journal_item(buf, len, offset)) { + header = (const struct log_header *)(buf + offset); + g_print("In replay found valid item at offset %zd\n", offset); + size_t size = GUINT32_FROM_LE(header->size1) + + GUINT32_FROM_LE(header->size2) + + GUINT32_FROM_LE(header->size3); + + BlueSkyCloudLog *log_item = bluesky_cloudlog_get(fs, header->id); + g_mutex_lock(log_item->lock); + *objects = g_list_prepend(*objects, log_item); + + log_item->inum = GUINT64_FROM_LE(header->inum); + reload_item(log_item, buf + offset + sizeof(struct log_header), + GUINT32_FROM_LE(header->size1), + GUINT32_FROM_LE(header->size2), + GUINT32_FROM_LE(header->size3)); + log_item->log_seq = log_seq; + log_item->log_offset = offset + sizeof(struct log_header); + log_item->log_size = header->size1; + + bluesky_string_unref(log_item->data); + log_item->data = bluesky_string_new(g_memdup(buf + offset + sizeof(struct log_header), GUINT32_FROM_LE(header->size1)), GUINT32_FROM_LE(header->size1)); + + /* For any inodes which were read from the journal, deserialize the + * inode information, overwriting any old inode data. */ + if (header->type - '0' == LOGTYPE_INODE) { + uint64_t inum = GUINT64_FROM_LE(header->inum); + BlueSkyInode *inode; + g_mutex_lock(fs->lock); + inode = (BlueSkyInode *)g_hash_table_lookup(fs->inodes, &inum); + if (inode == NULL) { + inode = bluesky_new_inode(inum, fs, BLUESKY_PENDING); + inode->change_count = 0; + bluesky_insert_inode(fs, inode); + } + g_mutex_lock(inode->lock); + bluesky_inode_free_resources(inode); + if (!bluesky_deserialize_inode(inode, log_item)) + g_print("Error deserializing inode %"PRIu64"\n", inum); + fs->next_inum = MAX(fs->next_inum, inum + 1); + bluesky_list_unlink(&fs->accessed_list, inode->accessed_list); + inode->accessed_list = bluesky_list_prepend(&fs->accessed_list, inode); + bluesky_list_unlink(&fs->dirty_list, inode->dirty_list); + inode->dirty_list = bluesky_list_prepend(&fs->dirty_list, inode); + bluesky_list_unlink(&fs->unlogged_list, inode->unlogged_list); + inode->unlogged_list = NULL; + inode->change_cloud = inode->change_commit; + bluesky_cloudlog_ref(log_item); + bluesky_cloudlog_unref(inode->committed_item); + inode->committed_item = log_item; + g_mutex_unlock(inode->lock); + g_mutex_unlock(fs->lock); + } + bluesky_string_unref(log_item->data); + log_item->data = NULL; + g_mutex_unlock(log_item->lock); + + offset += sizeof(struct log_header) + size + sizeof(struct log_footer); + } +} + +void bluesky_replay(BlueSkyFS *fs) +{ + BlueSkyLog *log = fs->log; + GList *logfiles = directory_contents(log->log_directory); + + /* Scan through log files in reverse order to find the most recent commit + * record. */ + logfiles = g_list_reverse(logfiles); + uint32_t seq_num = 0, start_offset = 0; + while (logfiles != NULL) { + char *filename = g_strdup_printf("%s/%s", log->log_directory, + (char *)logfiles->data); + g_print("Scanning file %s\n", filename); + GMappedFile *map = g_mapped_file_new(filename, FALSE, NULL); + if (map == NULL) { + g_warning("Mapping logfile %s failed!\n", filename); + } else { + bluesky_replay_scan_journal(g_mapped_file_get_contents(map), + g_mapped_file_get_length(map), + &seq_num, &start_offset); + g_mapped_file_unref(map); } - files = g_list_delete_link(files, files); + g_free(filename); + + g_free(logfiles->data); + logfiles = g_list_delete_link(logfiles, logfiles); + if (seq_num != 0 || start_offset != 0) + break; } - g_list_free(files); + g_list_foreach(logfiles, (GFunc)g_free, NULL); + g_list_free(logfiles); + + /* Now, scan forward starting from the given point in the log to + * reconstruct all filesystem state. As we reload objects we hold a + * reference to each loaded object. At the end we free all these + * references, so that any objects which were not linked into persistent + * filesystem data structures are freed. */ + GList *objects = NULL; + while (TRUE) { + char *filename = g_strdup_printf("%s/journal-%08d", + log->log_directory, seq_num); + g_print("Replaying file %s from offset %d\n", filename, start_offset); + GMappedFile *map = g_mapped_file_new(filename, FALSE, NULL); + g_free(filename); + if (map == NULL) { + g_warning("Mapping logfile failed, assuming end of journal\n"); + break; + } - g_mutex_unlock(fs->log->mmap_lock); + bluesky_replay_scan_journal2(fs, &objects, seq_num, start_offset, + g_mapped_file_get_contents(map), + g_mapped_file_get_length(map)); + g_mapped_file_unref(map); + seq_num++; + start_offset = 0; + } + + while (objects != NULL) { + bluesky_cloudlog_unref((BlueSkyCloudLog *)objects->data); + objects = g_list_delete_link(objects, objects); + } }