X-Git-Url: http://git.vrable.net/?p=bluesky.git;a=blobdiff_plain;f=bluesky%2Flog.c;h=ccc9a7a712bafc698ae17dfcc87cff6b50f2e2e9;hp=38606c1f69bb7d0020dee31cc21086fe715670ee;hb=b52abd849493636b81dda8c752a60834f1a6b91f;hpb=9f0e2f7de7d919d6a83944f0e7fdbd07cb6c4189 diff --git a/bluesky/log.c b/bluesky/log.c index 38606c1..ccc9a7a 100644 --- a/bluesky/log.c +++ b/bluesky/log.c @@ -34,13 +34,25 @@ * 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) - #define HEADER_MAGIC 0x676f4c0a #define FOOTER_MAGIC 0x2e435243 +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) { while (len > 0) { @@ -62,6 +74,16 @@ 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); @@ -110,7 +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); @@ -354,59 +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); - 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(); @@ -437,7 +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; @@ -447,6 +425,7 @@ 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); @@ -455,88 +434,314 @@ BlueSkyCacheFile *bluesky_cachefile_lookup(BlueSkyFS *fs, 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; } +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); + 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); +} + +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); + + 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; + } + + /* 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); + } + + 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); + } + + /* 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; + } + + /* 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(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; + 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(); } - BlueSkyLog *log = fs->log; - BlueSkyCacheFile *map = bluesky_cachefile_lookup(fs, log_dir, log_seq); - - if (map == NULL) { - return NULL; - } + bluesky_cloudlog_stats_update(item, -1); - /* 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"); + /* 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 (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); + 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; + } - 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; + /* 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; + } } + } - 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); - - g_print("Re-mapped log segment %d...\n", log_seq); - g_atomic_int_inc(&map->refcount); + if (map_data) { + if (location == CLOUDLOG_JOURNAL) + file_offset += sizeof(struct log_header); + else + file_offset += sizeof(struct cloudlog_header); - close(fd); + file_size = item->data_size; } + str = bluesky_cachefile_map_raw(map, file_offset, file_size); - BlueSkyRCStr *str; - map->atime = bluesky_get_current_time(); - str = bluesky_string_new_from_mmap(map, log_offset, log_size); +exit2: bluesky_cachefile_unref(map); g_mutex_unlock(map->lock); +exit1: + bluesky_cloudlog_stats_update(item, 1); return str; } @@ -547,14 +752,16 @@ 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); } /******************************* JOURNAL REPLAY *******************************