librbd: Update ImageCtx for new format

Detect the format when an image is opened by the presence of the
original format header object. Use member variables of ImageCtx to
store image metadata instead of the on-disk header format
ImageCtx::header.

This lays the foundation for changing the rest of librbd to work with
old and new formats.

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>

diff --git a/src/Makefile.am b/src/Makefile.am
index 0de11b6bda50ba804660edc5f7d41369a2264c04..d913e63287e6646b4c8dc777d0b54aaad0c36488 100644 (file)
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -353,6 +353,7 @@ endif
 # librbd
 librbd_la_SOURCES = \
        librbd.cc \
+       librbd/cls_rbd_client.cc \
        librbd/LibrbdWriteback.cc \
        osdc/ObjectCacher.cc
 librbd_la_CFLAGS = ${AM_CFLAGS}

diff --git a/src/librbd.cc b/src/librbd.cc
index 06d282594db28e57eb195470a76c66c8d965c668..ba8a851ef5d364104397ea0781bc4c2b8d2ca60e 100644 (file)
--- a/src/librbd.cc
+++ b/src/librbd.cc
@@ -24,8 +24,14 @@
 #include "include/rbd/librbd.hpp"
 #include "osdc/ObjectCacher.h"
 
+#include "librbd/cls_rbd_client.h"
 #include "librbd/LibrbdWriteback.h"
 
+#include <algorithm>
+#include <map>
+#include <string>
+#include <vector>
+
 #define dout_subsys ceph_subsys_rbd
 #undef dout_prefix
 #define dout_prefix *_dout << "librbd: "
@@ -86,9 +92,39 @@ namespace librbd {
   struct SnapInfo {
     snap_t id;
     uint64_t size;
-    SnapInfo(snap_t _id, uint64_t _size) : id(_id), size(_size) {};
+    uint64_t features;
+    SnapInfo(snap_t _id, uint64_t _size, uint64_t _features) :
+      id(_id), size(_size), features(_features) {};
   };
 
+  const string md_oid(const string &name, bool old_format)
+  {
+    if (old_format)
+      return name + RBD_SUFFIX;
+    else
+      return RBD_HEADER_PREFIX + name;
+  }
+
+  int detect_format(IoCtx &io_ctx, const string &name, bool *old_format,
+                   uint64_t *size)
+  {
+    CephContext *cct = (CephContext *)io_ctx.cct();
+    if (old_format)
+      *old_format = true;
+    int r = io_ctx.stat(md_oid(name, true), size, NULL);
+    if (r < 0) {
+      if (old_format)
+       *old_format = false;
+      r = io_ctx.stat(md_oid(name, false), size, NULL);
+      if (r < 0)
+       return r;
+    }
+
+    ldout(cct, 20) << "detect format of " << name << " : "
+                  << (*old_format ? "old" : "new") << dendl;
+    return 0;
+  }
+
   struct AioCompletion;
 
   struct AioBlockCompletion : Context {
@@ -114,7 +150,8 @@ namespace librbd {
     PerfCounters *perfcounter;
     struct rbd_obj_header_ondisk header;
     ::SnapContext snapc;
-    vector<snap_t> snaps;
+    vector<snap_t> snaps; // this mirrors snapc.snaps, but is in a
+                         // format librados can understand
     std::map<std::string, struct SnapInfo> snaps_by_name;
     uint64_t snapid;
     bool snap_exists; // false if our snapid was deleted
@@ -127,6 +164,13 @@ namespace librbd {
     Mutex lock; // protects access to snapshot and header information
     Mutex cache_lock; // used as client_lock for the ObjectCacher
 
+    bool old_format;
+    uint8_t order;
+    uint64_t size;
+    uint64_t features;
+    string object_prefix;
+    string header_oid;
+
     ObjectCacher *object_cacher;
     LibrbdWriteback *writeback_handler;
     ObjectCacher::ObjectSet *object_set;
@@ -141,6 +185,8 @@ namespace librbd {
        refresh_lock("librbd::ImageCtx::refresh_lock"),
        lock("librbd::ImageCtx::lock"),
        cache_lock("librbd::ImageCtx::cache_lock"),
+       old_format(true),
+       order(0), size(0), features(0),
        object_cacher(NULL), writeback_handler(NULL), object_set(NULL)
     {
       md_ctx.dup(p);
@@ -185,6 +231,26 @@ namespace librbd {
       }
     }
 
+    int init() {
+      int r = detect_format(md_ctx, name, &old_format, NULL);
+      if (r < 0) {
+       lderr(cct) << "error finding header: " << cpp_strerror(r) << dendl;
+       return r;
+      }
+
+      if (!old_format) {
+       r = cls_client::get_immutable_metadata(&md_ctx, md_oid(name, false),
+                                              &object_prefix, &order);
+       if (r < 0) {
+         lderr(cct) << "error reading immutable metadata: "
+                    << cpp_strerror(r) << dendl;
+         return r;
+       }
+      }
+      header_oid = md_oid(name, old_format);
+      return 0;
+    }
+
     void perf_start(string name) {
       PerfCountersBuilder plb(cct, name, l_librbd_first, l_librbd_last);
 
@@ -258,23 +324,17 @@ namespace librbd {
       return -ENOENT;
     }
 
-    void add_snap(std::string snap_name, snap_t id, uint64_t size)
+    void add_snap(std::string snap_name, snap_t id, uint64_t size, uint64_t features)
     {
-      snapc.snaps.push_back(id);
       snaps.push_back(id);
-      struct SnapInfo info(id, size);
+      struct SnapInfo info(id, size, features);
       snaps_by_name.insert(std::pair<std::string, struct SnapInfo>(snap_name, info));
     }
 
-    const string md_oid() const
-    {
-      return name + RBD_SUFFIX;
-    }
-
     uint64_t get_image_size() const
     {
       if (snapname.length() == 0) {
-       return header.image_size;
+       return size;
       } else {
        map<std::string,SnapInfo>::const_iterator p = snaps_by_name.find(snapname);
        if (p == snaps_by_name.end())
@@ -895,7 +955,7 @@ int snap_create(ImageCtx *ictx, const char *snap_name)
   if (r < 0)
     return r;
 
-  notify_change(ictx->md_ctx, ictx->md_oid(), NULL, ictx);
+  notify_change(ictx->md_ctx, ictx->header_oid, NULL, ictx);
 
   ictx->perfcounter->inc(l_librbd_snap_create);
   return 0;
@@ -923,7 +983,7 @@ int snap_remove(ImageCtx *ictx, const char *snap_name)
   if (r < 0)
     return r;
 
-  notify_change(ictx->md_ctx, ictx->md_oid(), NULL, ictx);
+  notify_change(ictx->md_ctx, ictx->header_oid, NULL, ictx);
 
   ictx->perfcounter->inc(l_librbd_snap_remove);
   return 0;
@@ -1113,7 +1173,7 @@ int resize_helper(ImageCtx *ictx, uint64_t size, ProgressContext& prog_ctx)
   // rewrite header
   bufferlist bl;
   bl.append((const char *)&(ictx->header), sizeof(ictx->header));
-  int r = ictx->md_ctx.write(ictx->md_oid(), bl, bl.length(), 0);
+  int r = ictx->md_ctx.write(ictx->header_oid, bl, bl.length(), 0);
 
   if (r == -ERANGE)
     lderr(cct) << "operation might have conflicted with another client!" << dendl;
@@ -1121,7 +1181,7 @@ int resize_helper(ImageCtx *ictx, uint64_t size, ProgressContext& prog_ctx)
     lderr(cct) << "error writing header: " << cpp_strerror(-r) << dendl;
     return r;
   } else {
-    notify_change(ictx->md_ctx, ictx->md_oid(), NULL, ictx);
+    notify_change(ictx->md_ctx, ictx->header_oid, NULL, ictx);
   }
 
   return 0;
@@ -1188,12 +1248,12 @@ int add_snap(ImageCtx *ictx, const char *snap_name)
   ::encode(snap_name, bl);
   ::encode(snap_id, bl);
 
-  r = ictx->md_ctx.exec(ictx->md_oid(), "rbd", "snap_add", bl, bl2);
+  r = ictx->md_ctx.exec(ictx->header_oid, "rbd", "snap_add", bl, bl2);
   if (r < 0) {
     lderr(ictx->cct) << "rbd.snap_add execution failed failed: " << cpp_strerror(-r) << dendl;
     return r;
   }
-  notify_change(ictx->md_ctx, ictx->md_oid(), NULL, ictx);
+  notify_change(ictx->md_ctx, ictx->header_oid, NULL, ictx);
 
   return 0;
 }
@@ -1205,7 +1265,7 @@ int rm_snap(ImageCtx *ictx, const char *snap_name)
   bufferlist bl, bl2;
   ::encode(snap_name, bl);
 
-  int r = ictx->md_ctx.exec(ictx->md_oid(), "rbd", "snap_remove", bl, bl2);
+  int r = ictx->md_ctx.exec(ictx->header_oid, "rbd", "snap_remove", bl, bl2);
   if (r < 0) {
     lderr(ictx->cct) << "rbd.snap_remove execution failed: " << cpp_strerror(-r) << dendl;
     return r;
@@ -1246,12 +1306,12 @@ int ictx_refresh(ImageCtx *ictx)
   ictx->needs_refresh = false;
   ictx->refresh_lock.Unlock();
 
-  int r = read_header(ictx->md_ctx, ictx->md_oid(), &(ictx->header), NULL);
+  int r = read_header(ictx->md_ctx, ictx->header_oid, &(ictx->header), NULL);
   if (r < 0) {
     lderr(cct) << "Error reading header: " << cpp_strerror(-r) << dendl;
     return r;
   }
-  r = ictx->md_ctx.exec(ictx->md_oid(), "rbd", "snap_list", bl, bl2);
+  r = ictx->md_ctx.exec(ictx->header_oid, "rbd", "snap_list", bl, bl2);
   if (r < 0) {
     lderr(cct) << "Error listing snapshots: " << cpp_strerror(-r) << dendl;
     return r;
@@ -1391,7 +1451,7 @@ int snap_rollback(ImageCtx *ictx, const char *snap_name, ProgressContext& prog_c
   snap_t new_snapid = ictx->get_snapid(snap_name);
   ldout(cct, 20) << "snapid is " << ictx->snapid << " new snapid is " << new_snapid << dendl;
 
-  notify_change(ictx->md_ctx, ictx->md_oid(), NULL, ictx);
+  notify_change(ictx->md_ctx, ictx->header_oid, NULL, ictx);
 
   ictx->perfcounter->inc(l_librbd_snap_rollback);
   return r;
@@ -1478,9 +1538,12 @@ int open_image(ImageCtx *ictx)
   ldout(ictx->cct, 20) << "open_image: ictx =  " << ictx
                       << " name =  '" << ictx->name << "' snap_name = '"
                       << ictx->snapname << "'" << dendl;
+  int r = ictx->init();
+  if (r < 0)
+    return r;
 
   ictx->lock.Lock();
-  int r = ictx_refresh(ictx);
+  r = ictx_refresh(ictx);
   ictx->lock.Unlock();
   if (r < 0)
     return r;
@@ -1491,7 +1554,7 @@ int open_image(ImageCtx *ictx)
   WatchCtx *wctx = new WatchCtx(ictx);
   ictx->wctx = wctx;
 
-  r = ictx->md_ctx.watch(ictx->md_oid(), 0, &(wctx->cookie), wctx);
+  r = ictx->md_ctx.watch(ictx->header_oid, 0, &(wctx->cookie), wctx);
   return r;
 }
 
@@ -1504,7 +1567,7 @@ void close_image(ImageCtx *ictx)
     flush(ictx);
   ictx->lock.Lock();
   ictx->wctx->invalidate();
-  ictx->md_ctx.unwatch(ictx->md_oid(), ictx->wctx->cookie);
+  ictx->md_ctx.unwatch(ictx->header_oid, ictx->wctx->cookie);
   delete ictx->wctx;
   ictx->lock.Unlock();
   delete ictx;