filestore: optionally checkpoint with snaps

diff --git a/src/config.cc b/src/config.cc
index f889af9bbf7ec7ca8ba40a4b3396d710d137dea5..a0c040aa5e6dcc9de4509fb63ca75248c61a12c8 100644 (file)
--- a/src/config.cc
+++ b/src/config.cc
@@ -526,6 +526,7 @@ static struct config_option config_optionsp[] = {
        OPTION(filestore_fake_collections, 0, OPT_BOOL, false),
        OPTION(filestore_dev, 0, OPT_STR, 0),
        OPTION(filestore_btrfs_trans, 0, OPT_BOOL, true),
+       OPTION(filestore_btrfs_snap, 0, OPT_BOOL, false),
        OPTION(filestore_flusher, 0, OPT_BOOL, true),
        OPTION(filestore_flusher_max_fds, 0, OPT_INT, 512),
        OPTION(filestore_sync_flush, 0, OPT_BOOL, false),

diff --git a/src/config.h b/src/config.h
index 7a3dc51441343b1031ef1ba34a2733368f6f54e7..3bfe0f2136ab49dd81161b082678c4008a41f70a 100644 (file)
--- a/src/config.h
+++ b/src/config.h
@@ -337,6 +337,7 @@ struct md_config_t {
   bool  filestore_fake_collections;
   const char  *filestore_dev;
   bool filestore_btrfs_trans;
+  bool filestore_btrfs_snap;
   bool filestore_flusher;
   int filestore_flusher_max_fds;
   bool filestore_sync_flush;

diff --git a/src/os/FileStore.cc b/src/os/FileStore.cc
index d810913c53f91960273d1ed3bf187c164b8699e2..569e82c33df8d85f481735eb9da898269abe4f79 100644 (file)
--- a/src/os/FileStore.cc
+++ b/src/os/FileStore.cc
@@ -49,7 +49,7 @@
 
 #define ATTR_MAX 80
 
-#define COMMIT_SNAP_ITEM "%lld"
+#define COMMIT_SNAP_ITEM "snap_%lld"
 
 #ifndef __CYGWIN__
 # ifndef DARWIN
@@ -287,8 +287,6 @@ int FileStore::mkfs()
   volargs.fd = 0;
   strcpy(volargs.name, "current");
   int r = ::ioctl(fd, BTRFS_IOC_SUBVOL_CREATE, (unsigned long int)&volargs);
-  char current_fn[PATH_MAX];
-  snprintf(current_fn, sizeof(current_fn), "%s/current", basedir.c_str());
   if (r == 0) {
     // yay
     dout(2) << " created btrfs subvol " << current_fn << dendl;
@@ -446,10 +444,13 @@ int FileStore::mount()
   Transaction empty;
   btrfs = 1;
 
-  btrfs_snap = false;
-  if (btrfs_snap) {
-    snapdir_fd = ::open(basedir.c_str(), O_RDONLY);
+  // open some dir handles
+  basedir_fd = ::open(basedir.c_str(), O_RDONLY);
+  current_fd = ::open(current_fn, O_RDONLY);
+  dout(10) << "basedir_fd " << basedir_fd << "=" << basedir
+          << ", current_fd " << current_fd << "=" << current_fn << dendl;
 
+  if (true) { //g_conf.filestore_btrfs_snap) {
     // get snap list
     DIR *dir = ::opendir(basedir.c_str());
     if (!dir)
@@ -558,6 +559,8 @@ int FileStore::umount()
 
   ::close(fsid_fd);
   ::close(op_fd);
+  ::close(current_fd);
+  ::close(basedir_fd);
 
   if (g_conf.filestore_dev) {
     char cmd[PATH_MAX];
@@ -1379,22 +1382,24 @@ void FileStore::sync_entry()
 
       dout(15) << "sync_entry committing " << cp << " sync_epoch " << sync_epoch << dendl;
 
+      bool do_snap = g_conf.filestore_btrfs_snap;
 
-      if (btrfs_snap) {
+      if (do_snap) {
        btrfs_ioctl_vol_args snapargs;
-       snapargs.fd = snapdir_fd;
+       snapargs.fd = current_fd;
        snprintf(snapargs.name, sizeof(snapargs.name), COMMIT_SNAP_ITEM, (long long unsigned)cp);
-       dout(0) << "taking snap '" << snapargs.name << "'" << dendl;
-       int r = ::ioctl(snapargs.fd, BTRFS_IOC_SNAP_CREATE, &snapargs);
+       dout(10) << "taking snap '" << snapargs.name << "'" << dendl;
+       int r = ::ioctl(basedir_fd, BTRFS_IOC_SNAP_CREATE, &snapargs);
        char buf[100];
-       dout(0) << "snap create '" << snapargs.name << "' got " << r
+       dout(20) << "snap create '" << snapargs.name << "' got " << r
                << " " << strerror_r(r < 0 ? errno : 0, buf, sizeof(buf)) << dendl;
+       assert(r == 0);
        snaps.push_back(cp);
       }
 
       commit_started();
 
-      if (!btrfs_snap) {
+      if (!do_snap) {
        if (btrfs) {
          dout(15) << "sync_entry doing btrfs sync" << dendl;
          // do a full btrfs commit
@@ -1412,17 +1417,18 @@ void FileStore::sync_entry()
       commit_finish();
 
       // remove old snaps?
-      if (false && btrfs_snap) {
+      if (do_snap) {
        while (snaps.size() > 2) {
          btrfs_ioctl_vol_args snapargs;
-         snapargs.fd = snapdir_fd;
+         snapargs.fd = 0;
          snprintf(snapargs.name, sizeof(snapargs.name), COMMIT_SNAP_ITEM, (long long unsigned)snaps.front());
          snaps.pop_front();
-         dout(0) << "removing snap '" << snapargs.name << "'" << dendl;
-         int r = ::ioctl(snapargs.fd, BTRFS_IOC_SNAP_DESTROY, &snapargs);
+         dout(10) << "removing snap '" << snapargs.name << "'" << dendl;
+         int r = ::ioctl(basedir_fd, BTRFS_IOC_SNAP_DESTROY, &snapargs);
          char buf[100];
-         dout(0) << "snap destroyed '" << snapargs.name << "' got " << r
+         dout(20) << "snap destroyed '" << snapargs.name << "' got " << r
                  << " " << strerror_r(r < 0 ? errno : 0, buf, sizeof(buf)) << dendl;
+         assert(r == 0);
        }
       }
 

diff --git a/src/os/FileStore.h b/src/os/FileStore.h
index a467450c424c7d4f29c3044bab2c02331039140d..11bde4f07bfe282d5d6947f8b05821a2bd92257c 100644 (file)
--- a/src/os/FileStore.h
+++ b/src/os/FileStore.h
@@ -35,14 +35,14 @@ using namespace __gnu_cxx;
 
 class FileStore : public JournalingObjectStore {
   string basedir, journalpath;
+  char current_fn[PATH_MAX];
   __u64 fsid;
   
   int btrfs;
-  bool btrfs_snap;
   bool btrfs_trans_start_end;
   int fsid_fd, op_fd;
 
-  int snapdir_fd;
+  int basedir_fd, current_fd;
   deque<__u64> snaps;
 
   // fake attrs?
@@ -126,14 +126,17 @@ class FileStore : public JournalingObjectStore {
  public:
   FileStore(const char *base, const char *jdev = 0) : 
     basedir(base), journalpath(jdev ? jdev:""),
-    btrfs(false), btrfs_snap(false), btrfs_trans_start_end(false),
+    btrfs(false), btrfs_trans_start_end(false),
     fsid_fd(-1), op_fd(-1),
     attrs(this), fake_attrs(false), 
     collections(this), fake_collections(false),
     lock("FileStore::lock"),
     sync_epoch(0), stop(false), sync_thread(this),
     op_lock("FileStore::op_lock"), op_queue_len(0), op_queue_bytes(0), op_thread(this),
-    flusher_queue_len(0), flusher_thread(this) { }
+    flusher_queue_len(0), flusher_thread(this) {
+    // init current_fn
+    snprintf(current_fn, sizeof(current_fn), "%s/current", basedir.c_str());
+  }
 
   int mount();
   int umount();