* 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)
{
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);
}
}
- 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);
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);
}
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;
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));
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;
+ item->log_offset = offset;
+ item->log_size = size;
+ item->data_size = item->data->len;
+
+ offset += size;
- offset += sizeof(header) + sizeof(footer) + item->data->len;
+ 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
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);
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");
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)
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);
}
}
+/* 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;
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();
/* 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;
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;
+ }
+ }
+ }
- BlueSkyRCStr *str;
- map->atime = bluesky_get_current_time();
- str = bluesky_string_new_from_mmap(map, log_offset, log_size);
+ if (map_data) {
+ if (location == CLOUDLOG_JOURNAL)
+ file_offset += sizeof(struct log_header);
+ else
+ file_offset += sizeof(struct cloudlog_header);
+
+ 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;
}
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 atime_age=%f",
- cachefile->filename, cachefile->addr, cachefile->mapcount,
- cachefile->refcount, age / 1e6);
- if (cachefile->fetching)
- g_print(" (fetching)");
- g_print("\n");
-
- gboolean deletion_candidate = FALSE;
- 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)
- {
- deletion_candidate = TRUE;
- }
+ 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);
+ }
+}
- /* Don't allow journal files to be reclaimed until all data is
- * known to be durably stored in the cloud. */
- if (cachefile->type == CLOUDLOG_JOURNAL
- && cachefile->log_seq >= fs->log->journal_watermark)
- {
- deletion_candidate = FALSE;
+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);
+ }
- if (deletion_candidate) {
- g_print(" ...deleting\n");
- if (unlinkat(fs->log->dirfd, cachefile->filename, 0) < 0) {
- fprintf(stderr, "Unable to unlink journal %s: %m\n",
- cachefile->filename);
- }
+ 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;
+}
- 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 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);
+ }
}