return -1;
}
- /* The index data consists of a sequence of pointers to the data blocks
- * that actually comprise the file data. This level of indirection is used
- * so that the same data block can be used in multiple files, or multiple
- * versions of the same file. */
- SHA1Checksum hash;
- while (true) {
- size_t bytes = file_read(fd, block_buf, LBS_BLOCK_SIZE);
- if (bytes == 0)
- break;
-
- hash.process(block_buf, bytes);
-
- // Either find a copy of this block in an already-existing segment, or
- // index it so it can be re-used in the future
- SHA1Checksum block_hash;
- block_hash.process(block_buf, bytes);
- string block_csum = block_hash.checksum_str();
- ObjectReference ref = db->FindObject(block_csum, bytes);
-
- // Store a copy of the object if one does not yet exist
- if (ref.get_segment().size() == 0) {
- LbsObject *o = new LbsObject;
-
- /* We might still have seen this checksum before, if the object was
- * stored at some time in the past, but we have decided to clean
- * the segment the object was originally stored in (FindObject will
- * not return such objects). When rewriting the object contents,
- * put it in a separate group, so that old objects get grouped
- * together. The hope is that these old objects will continue to
- * be used in the future, and we obtain segments which will
- * continue to be well-utilized. */
- if (db->IsOldObject(block_csum, bytes))
- o->set_group("compacted");
- else
- o->set_group("data");
-
- o->set_data(block_buf, bytes);
- o->write(tss);
- ref = o->get_ref();
- db->StoreObject(ref, block_csum, bytes);
- delete o;
+ /* Look up this file in the old stat cache, if we can. If the stat
+ * information indicates that the file has not changed, do not bother
+ * re-reading the entire contents. */
+ bool cached = false;
+
+ if (statcache->Find(path, &stat_buf)) {
+ cached = true;
+ const list<ObjectReference> &blocks = statcache->get_blocks();
+
+ /* If any of the blocks in the object have been expired, then we should
+ * fall back to fully reading in the file. */
+ for (list<ObjectReference>::const_iterator i = blocks.begin();
+ i != blocks.end(); ++i) {
+ const ObjectReference &ref = *i;
+ if (!db->IsAvailable(ref)) {
+ cached = false;
+ break;
+ }
}
- object_list.push_back(ref.to_string());
- segment_list.insert(ref.get_segment());
- db->UseObject(ref);
- size += bytes;
+ /* If everything looks okay, use the cached information */
+ if (cached) {
+ file_info["checksum"] = statcache->get_checksum();
+ for (list<ObjectReference>::const_iterator i = blocks.begin();
+ i != blocks.end(); ++i) {
+ const ObjectReference &ref = *i;
+ object_list.push_back(ref.to_string());
+ segment_list.insert(ref.get_segment());
+ db->UseObject(ref);
+ }
+ size = stat_buf.st_size;
+ }
}
- file_info["checksum"] = hash.checksum_str();
+ /* If the file is new or changed, we must read in the contents a block at a
+ * time. */
+ if (!cached) {
+ printf(" [new]\n");
+
+ SHA1Checksum hash;
+ while (true) {
+ size_t bytes = file_read(fd, block_buf, LBS_BLOCK_SIZE);
+ if (bytes == 0)
+ break;
+
+ hash.process(block_buf, bytes);
+
+ // Either find a copy of this block in an already-existing segment,
+ // or index it so it can be re-used in the future
+ double block_age = 0.0;
+ SHA1Checksum block_hash;
+ block_hash.process(block_buf, bytes);
+ string block_csum = block_hash.checksum_str();
+ ObjectReference ref = db->FindObject(block_csum, bytes);
+
+ // Store a copy of the object if one does not yet exist
+ if (ref.get_segment().size() == 0) {
+ LbsObject *o = new LbsObject;
+
+ /* We might still have seen this checksum before, if the object
+ * was stored at some time in the past, but we have decided to
+ * clean the segment the object was originally stored in
+ * (FindObject will not return such objects). When rewriting
+ * the object contents, put it in a separate group, so that old
+ * objects get grouped together. The hope is that these old
+ * objects will continue to be used in the future, and we
+ * obtain segments which will continue to be well-utilized.
+ * Additionally, keep track of the age of the data by looking
+ * up the age of the block which was expired and using that
+ * instead of the current time. */
+ if (db->IsOldObject(block_csum, bytes, &block_age))
+ o->set_group("compacted");
+ else
+ o->set_group("data");
+
+ o->set_data(block_buf, bytes);
+ o->write(tss);
+ ref = o->get_ref();
+ db->StoreObject(ref, block_csum, bytes, block_age);
+ delete o;
+ }
+
+ object_list.push_back(ref.to_string());
+ segment_list.insert(ref.get_segment());
+ db->UseObject(ref);
+ size += bytes;
+ }
+
+ file_info["checksum"] = hash.checksum_str();
+ }
statcache->Save(path, &stat_buf, file_info["checksum"], object_list);
root->checksum();
segment_list.insert(root->get_ref().get_segment());
+ string backup_root = root->get_ref().to_string();
+ delete root;
+
+ db->Close();
+
+ statcache->Close();
+ delete statcache;
+
+ tss->sync();
+ tss->dump_stats();
+ delete tss;
+
/* Write a backup descriptor file, which says which segments are needed and
* where to start to restore this snapshot. The filename is based on the
* current time. */
descriptor << "Format: LBS Snapshot v0.1\n";
strftime(desc_buf, sizeof(desc_buf), "%Y-%m-%d %H:%M:%S %z", &time_buf);
descriptor << "Date: " << desc_buf << "\n";
- descriptor << "Root: " << root->get_ref().to_string() << "\n";
-
- delete root;
+ descriptor << "Root: " << backup_root << "\n";
descriptor << "Segments:\n";
for (std::set<string>::iterator i = segment_list.begin();
descriptor << " " << *i << "\n";
}
- db->Close();
-
- statcache->Close();
- delete statcache;
-
- tss->sync();
- delete tss;
-
return 0;
}
projects / cumulus.git / blobdiff