os, osd, tools: Add backportable compatibility checking for sharded objectswip-compat-cuttlefish

OSD
  New CEPH_OSD_FEATURE_INCOMPAT_SHARDS
FileStore
  NEW CEPH_FS_FEATURE_INCOMPAT_SHARDS
  Add FSSuperblock with feature CompatSet in it
  Store sharded_objects state using CompatSet
  Add set_allow_sharded_objects() and get_allow_sharded_objects() to FileStore/ObjectStore
  Add read_superblock()/write_superblock() internal filestore functions
ceph_filestore_dump
  Add OSDsuperblock to export format
  Use CompatSet from OSD code itself in filestore-dump tool
  Always check compatibility of OSD features with on-disk features
  On import verify compatibility of on-disk features with export data
  Bump super_ver due to export format change

Backport: dumpling, cuttlefish

Signed-off-by: David Zafman <david.zafman@inktank.com>
(cherry picked from commit 5b70c2b0108f744c171364f26475fb7baaa8b6fe)

Conflicts:

	src/os/FileStore.cc
	src/os/FileStore.h
	src/osd/OSD.cc
	src/osd/OSD.h

1 files changed, 26 insertions, 0 deletions

diff --git a/src/os/FileStore.h b/src/os/FileStore.h
index e4f7e81a502..a8aacbf5373 100644
--- a/src/os/FileStore.h
+++ b/src/os/FileStore.h
@@ -49,6 +49,26 @@ using namespace __gnu_cxx;
 # define FALLOC_FL_PUNCH_HOLE 0x2
 #endif
 
+#define CEPH_FS_FEATURE_INCOMPAT_SHARDS CompatSet::Feature(1, "sharded objects")
+
+class FSSuperblock {
+public:
+  CompatSet compat_features;
+
+  FSSuperblock() { }
+
+  void encode(bufferlist &bl) const;
+  void decode(bufferlist::iterator &bl);
+  void dump(Formatter *f) const;
+  static void generate_test_instances(list<FSSuperblock*>& o);
+};
+WRITE_CLASS_ENCODER(FSSuperblock)
+
+inline ostream& operator<<(ostream& out, const FSSuperblock& sb)
+{
+  return out << "sb(" << sb.compat_features << ")";
+}
+
 class FileStore : public JournalingObjectStore,
                   public md_config_obs_t
 {
@@ -303,6 +323,8 @@ public:
   int get_max_object_name_length();
   int mkfs();
   int mkjournal();
+  void set_allow_sharded_objects();
+  bool get_allow_sharded_objects();
 
   int statfs(struct statfs *buf);
 
@@ -538,6 +560,10 @@ private:
   std::ofstream m_filestore_dump;
   JSONFormatter m_filestore_dump_fmt;
   atomic_t m_filestore_kill_at;
+  FSSuperblock superblock;
+
+  int write_superblock();
+  int read_superblock();
 };
 
 ostream& operator<<(ostream& out, const FileStore::OpSequencer& s);