filestore: don't revert to old snapshots on startup

This should fix bug #55

diff --git a/src/os/FileStore.cc b/src/os/FileStore.cc
index 10efa525dfc6728bd813f3d69df234e80ec9687c..b0fc9b763aa9ef0ee9b5b25c12d47f77348747c8 100644 (file)
--- a/src/os/FileStore.cc
+++ b/src/os/FileStore.cc
@@ -973,37 +973,40 @@ int FileStore::mount()
       int curr_fd = read_op_seq(current_op_seq_fn, &curr_seq);
       if (curr_fd >= 0)
         close(curr_fd);
-      dout(0) << "*** curr_seq=" << curr_seq << " cp=" << cp << dendl;
+      dout(10) << "*** curr_seq=" << curr_seq << " cp=" << cp << dendl;
       
-
-      // drop current
-      snapargs.fd = 0;
-      strcpy(snapargs.name, "current");
-      int r = ::ioctl(basedir_fd,
-                     BTRFS_IOC_SNAP_DESTROY,
-                     &snapargs);
-      if (r) {
-       char buf[80];
-       dout(0) << "error removing old current subvol: " << strerror_r(errno, buf, sizeof(buf)) << dendl;
-       char s[PATH_MAX];
-       snprintf(s, sizeof(s), "%s/current.remove.me.%d", basedir.c_str(), rand());
-       r = ::rename(current_fn, s);
-       if (r) {
-         dout(0) << "error renaming old current subvol: " << strerror_r(errno, buf, sizeof(buf)) << dendl;
-         return -errno;
-       }
-      }
-      assert(r == 0);
+      if (cp >= curr_seq) {
+        // drop current
+        snapargs.fd = 0;
+        strcpy(snapargs.name, "current");
+        int r = ::ioctl(basedir_fd,
+                       BTRFS_IOC_SNAP_DESTROY,
+                       &snapargs);
+        if (r) {
+         char buf[80];
+         dout(0) << "error removing old current subvol: " << strerror_r(errno, buf, sizeof(buf)) << dendl;
+         char s[PATH_MAX];
+         snprintf(s, sizeof(s), "%s/current.remove.me.%d", basedir.c_str(), rand());
+         r = ::rename(current_fn, s);
+         if (r) {
+           dout(0) << "error renaming old current subvol: " << strerror_r(errno, buf, sizeof(buf)) << dendl;
+           return -errno;
+         }
+        }
+        assert(r == 0);
       
-      // roll back
-      char s[PATH_MAX];
-      snprintf(s, sizeof(s), "%s/" COMMIT_SNAP_ITEM, basedir.c_str(), (long long unsigned)cp);
-      snapargs.fd = ::open(s, O_RDONLY);
-      r = ::ioctl(basedir_fd, BTRFS_IOC_SNAP_CREATE, &snapargs);
-      assert(r == 0);
-      ::close(snapargs.fd);
-      dout(10) << "mount rolled back to consistent snap " << cp << dendl;
-      snaps.pop_back();
+        // roll back
+        char s[PATH_MAX];
+        snprintf(s, sizeof(s), "%s/" COMMIT_SNAP_ITEM, basedir.c_str(), (long long unsigned)cp);
+        snapargs.fd = ::open(s, O_RDONLY);
+        r = ::ioctl(basedir_fd, BTRFS_IOC_SNAP_CREATE, &snapargs);
+        assert(r == 0);
+        ::close(snapargs.fd);
+        dout(10) << "mount rolled back to consistent snap " << cp << dendl;
+        snaps.pop_back();
+      } else {
+          dout(0) << "WARNING: skipping revert of current subvol to last snap, curr_seq=" << curr_seq << " snap seq=" << cp << dendl;
+      }
     }
   }