}
}
- 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);
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);
- async->data = bluesky_string_dup(async->data);
- bluesky_cloudlog_decrypt(async->data->data, async->data->len,
- cachefile->fs->keys, cachefile->items);
- 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();
g_hash_table_insert(log->mmap_cache, map->filename, map);
+ int fd = openat(log->dirfd, logname, O_WRONLY | O_CREAT, 0600);
+ if (fd >= 0) {
+ ftruncate(fd, 5 << 20); // FIXME
+ close(fd);
+ }
+
// If the log file is stored in the cloud, we may need to fetch it
- if (clouddir >= 0)
+ if (clouddir >= 0 && start_fetch)
cloudlog_fetch_start(map);
} else {
g_mutex_lock(map->lock);
return map;
}
+static void robust_pwrite(int fd, const char *buf, ssize_t count, off_t offset)
+{
+ 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;
+ }
+}
+
+static void cloudlog_partial_fetch_complete(BlueSkyStoreAsync *async,
+ BlueSkyCacheFile *cachefile);
+
+static void cloudlog_partial_fetch_start(BlueSkyCacheFile *cachefile,
+ size_t offset, size_t length)
+{
+ g_atomic_int_inc(&cachefile->refcount);
+ 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->start = offset;
+ async->len = length;
+ bluesky_store_async_add_notifier(async,
+ (GFunc)cloudlog_partial_fetch_complete,
+ cachefile);
+ bluesky_store_async_submit(async);
+ bluesky_store_async_unref(async);
+}
+
+static void cloudlog_partial_fetch_complete(BlueSkyStoreAsync *async,
+ BlueSkyCacheFile *cachefile)
+{
+ g_print("Partial fetch of %s from cloud complete, status = %d\n",
+ async->key, async->result);
+
+ g_mutex_lock(cachefile->lock);
+ if (async->result >= 0) {
+ /* 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) {
+ async->data = bluesky_string_dup(async->data);
+ bluesky_cloudlog_decrypt(async->data->data, async->data->len,
+ cachefile->fs->keys, items);
+ uint64_t item_offset = 0;
+ while (TRUE) {
+ const BlueSkyRangesetItem *item;
+ item = bluesky_rangeset_lookup_next(items, item_offset);
+ if (item == NULL)
+ break;
+ 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);
+ }
+ } else {
+ g_print("Error fetching from cloud, retrying...\n");
+ cloudlog_partial_fetch_start(cachefile, async->start, async->len);
+ }
+
+ 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;
+ 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_partial_fetch_complete,
+ cachefile);
+ bluesky_store_async_submit(async);
+ bluesky_store_async_unref(async);
+}
+
/* 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(BlueSkyFS *fs, int log_dir,
- int log_seq, int log_offset, int log_size,
- gboolean map_data)
+BlueSkyRCStr *bluesky_log_map_object(BlueSkyCloudLog *item, gboolean map_data)
{
+ BlueSkyFS *fs = item->fs;
+ BlueSkyLog *log = fs->log;
+ BlueSkyCacheFile *map = NULL;
+ BlueSkyRCStr *str = NULL;
+ int location = 0;
+ size_t file_offset = 0, file_size = 0;
+ gboolean range_request = TRUE;
+
if (page_size == 0) {
page_size = getpagesize();
}
- BlueSkyLog *log = fs->log;
- BlueSkyCacheFile *map = bluesky_cachefile_lookup(fs, log_dir, log_seq);
+ bluesky_cloudlog_stats_update(item, -1);
- if (map == NULL) {
- return NULL;
+ /* 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;
+ }
}
- /* Log segments fetched from the cloud might only be partially-fetched.
- * Check whether the object we are interested in is available. */
- if (log_dir >= 0) {
- const BlueSkyRangesetItem *rangeitem;
- rangeitem = bluesky_rangeset_lookup(map->items, log_offset);
- if (rangeitem == NULL || rangeitem->start != log_offset) {
- g_warning("log-%d: Item at offset %d does not seem to be available\n", log_seq, log_offset);
- }
- if (map_data && rangeitem != NULL
- && log_offset > rangeitem->start
- && log_size <= rangeitem->length - (log_offset - rangeitem->start))
- {
- g_warning(" ...allowing access to middle of log item");
+ 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;
}
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);
- }
-
int fd = openat(log->dirfd, map->filename, O_RDONLY);
if (fd < 0) {
fprintf(stderr, "Error opening logfile %s: %m\n", map->filename);
- bluesky_cachefile_unref(map);
- g_mutex_unlock(map->lock);
- return NULL;
+ goto exit2;
}
off_t length = lseek(fd, 0, SEEK_END);
map->len = length;
g_atomic_int_add(&log->disk_used, map->len / 1024);
- g_print("Re-mapped log segment %d...\n", log_seq);
g_atomic_int_inc(&map->refcount);
close(fd);
}
- BlueSkyRCStr *str;
+ /* 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) {
+ g_print("Item at offset 0x%zx not available, need to fetch.\n",
+ file_offset);
+ if (range_request)
+ cloudlog_partial_fetch_start(map, file_offset, file_size);
+ g_cond_wait(map->cond, map->lock);
+ } else if (rangeitem->start == file_offset
+ && rangeitem->length == file_size) {
+ g_print("Item now available.\n");
+ break;
+ }
+ }
+ }
+
+ 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_string_new_from_mmap(map, file_offset, file_size);
map->atime = bluesky_get_current_time();
- str = bluesky_string_new_from_mmap(map, log_offset, log_size);
+
+ g_print("Returning item at offset 0x%zx.\n", file_offset);
+
+exit2:
bluesky_cachefile_unref(map);
g_mutex_unlock(map->lock);
+exit1:
+ bluesky_cloudlog_stats_update(item, 1);
return str;
}
projects / bluesky.git / commitdiff