mds client: initial steps for cap-less opens of snapped files

diff --git a/src/client/Client.cc b/src/client/Client.cc
index 5bf483d005b539ef0005cc73acaacc226e469731..2abf26dc2cfd85ce61c68c4c3f04296cc5db5712 100644 (file)
--- a/src/client/Client.cc
+++ b/src/client/Client.cc
@@ -1394,6 +1394,8 @@ void Client::check_caps(Inode *in, bool flush_snap)
           << " wanted " << cap_string(wanted)
           << " used " << cap_string(used)
           << dendl;
+
+  assert(in->snapid == CEPH_NOSNAP);
   
   if (in->caps.empty())
     return;   // guard if at end of func
@@ -3205,14 +3207,22 @@ int Client::_open(const filepath &path, int flags, mode_t mode, Fh **fhp, int ui
 
     dout(10) << in->inode.ino << " mode " << cmode << dendl;
 
-    // add the cap
     int mds = reply->get_source().num();
-    add_update_cap(in, mds,
-                  reply->snapbl,
-                  reply->get_file_caps(),
-                  reply->get_file_caps_seq(),
-                  reply->get_file_caps_mseq());    
-    dout(5) << "open success, fh is " << f << " combined caps " << cap_string(in->caps_issued()) << dendl;
+    if (in->snapid == CEPH_NOSNAP) {
+      // add the cap
+      add_update_cap(in, mds,
+                    reply->snapbl,
+                    reply->get_file_caps(),
+                    reply->get_file_caps_seq(),
+                    reply->get_file_caps_mseq());    
+      dout(5) << "open success, fh is " << f << " combined caps " << cap_string(in->caps_issued()) << dendl;
+    } else {
+      in->snap_caps |= reply->get_file_caps();
+      in->snap_cap_refs++;
+      dout(5) << "open success, fh is " << f << " combined IMMUTABLE SNAP caps " 
+             << cap_string(in->caps_issued()) << dendl;
+
+    }
   }
 
   delete reply;
@@ -3248,11 +3258,17 @@ int Client::_release(Fh *f)
   dout(5) << "_release " << f << dendl;
   Inode *in = f->inode;
 
-  if (in->put_open_ref(f->mode))
-    check_caps(in);
-  put_inode( in );
+  if (in->snapid == CEPH_NOSNAP) {
+    if (in->put_open_ref(f->mode))
+      check_caps(in);
+  } else {
+    assert(in->snap_cap_refs > 0);
+    in->snap_cap_refs--;
+  }
 
+  put_inode( in );
   delete f;
+
   return 0;
 }
 
@@ -3458,9 +3474,16 @@ int Client::_read(Fh *f, __s64 offset, __u64 size, bufferlist *bl)
       }
 
       // read (and possibly block)
-      r = objectcacher->file_read(in->inode.ino, &in->inode.layout,
-                                 CEPH_NOSNAP, in->snaprealm->get_snaps(),
-                                 offset, size, bl, 0, onfinish);
+      vector<snapid_t> emptysnaps;
+      if (in->snapid == CEPH_NOSNAP)
+       r = objectcacher->file_read(in->inode.ino, &in->inode.layout,
+                                   CEPH_NOSNAP, in->snaprealm->get_snaps(),
+                                   offset, size, bl, 0, onfinish);
+      else
+       r = objectcacher->file_read(in->inode.ino, &in->inode.layout,
+                                   in->snapid, emptysnaps,
+                                   offset, size, bl, 0, onfinish);
+
       
       if (r == 0) {
        while (!done) 
@@ -3576,6 +3599,8 @@ int Client::_write(Fh *f, __s64 offset, __u64 size, const char *buf)
   //dout(7) << "write fh " << fh << " size " << size << " offset " << offset << dendl;
   Inode *in = f->inode;
 
+  assert(in->snapid == CEPH_NOSNAP);
+
   // use/adjust fd pos?
   if (offset < 0) {
     lock_fh_pos(f);

diff --git a/src/client/Client.h b/src/client/Client.h
index c0f223000508315f5239d8049fc8228f81d3e498..77bb9bedac3e15137dd7bfbbcc309056e5f709bd 100644 (file)
--- a/src/client/Client.h
+++ b/src/client/Client.h
@@ -188,6 +188,7 @@ class Inode {
 
   // per-mds caps
   map<int,InodeCap*> caps;            // mds -> InodeCap
+  int snap_caps, snap_cap_refs;
   unsigned exporting_issued;
   int exporting_mds;
   capseq_t exporting_mseq;
@@ -253,6 +254,7 @@ class Inode {
     snapid(vino.snapid),
     lease_mask(0), lease_mds(-1),
     dir_auth(-1), dir_hashed(false), dir_replicated(false), 
+    snap_caps(0), snap_cap_refs(0),
     exporting_issued(0), exporting_mds(-1), exporting_mseq(0),
     snaprealm(0), snaprealm_item(this), snapdir_parent(0),
     reported_size(0), wanted_max_size(0), requested_max_size(0),
@@ -289,7 +291,7 @@ class Inode {
   bool put_cap_ref(int cap);
 
   int caps_issued() {
-    int c = exporting_issued;
+    int c = exporting_issued | snap_caps;
     for (map<int,InodeCap*>::iterator it = caps.begin();
          it != caps.end();
          it++)

diff --git a/src/mds/Server.cc b/src/mds/Server.cc
index c2844bfe6c333c8517a357d4ade03b2d7d718c7b..b7ea1a7b679fda0835237ab207d820f0dab5c91a 100644 (file)
--- a/src/mds/Server.cc
+++ b/src/mds/Server.cc
@@ -1335,7 +1335,7 @@ CInode* Server::rdlock_path_pin_ref(MDRequest *mdr,
       CDentry *last = mdr->trace[mdr->trace.size()-1];
       assert(last->get_inode() == mdr->ref);
     }
-    dout(10) << "rdlock_path_pin_ref had " << *mdr->ref << dendl;
+    dout(10) << "rdlock_path_pin_ref had snap " << mdr->ref_snapid << " " << *mdr->ref << dendl;
     return mdr->ref;
   }
 
@@ -4550,6 +4550,14 @@ void Server::handle_client_open(MDRequest *mdr)
     return;
   }
   
+  // snapped data is read only
+  if (mdr->ref_snapid != CEPH_NOSNAP &&
+      (cmode & CEPH_FILE_MODE_WR)) {
+    dout(7) << "snap " << mdr->ref_snapid << " is read-only " << *cur << dendl;
+    reply_request(mdr, -EPERM);
+    return;
+  }
+
   // hmm, check permissions or something.
 
   // O_TRUNC
@@ -4580,21 +4588,47 @@ void Server::_do_open(MDRequest *mdr, CInode *cur)
 {
   MClientRequest *req = mdr->client_request;
   int cmode = ceph_flags_to_mode(req->head.args.open.flags);
-  if (cur->inode.is_dir()) cmode = CEPH_FILE_MODE_PIN;
-
-  // register new cap
-  bool is_new = false;
-  Capability *cap = mds->locker->issue_new_caps(cur, cmode, mdr->session, is_new);
-
-  // drop our locks (they may interfere with us issuing new caps)
-  mdcache->request_drop_locks(mdr);
+  if (cur->inode.is_dir()) 
+    cmode = CEPH_FILE_MODE_PIN;
 
-  if (is_new)
-    cap->dec_suppress();  // stop suppressing messages on new cap
+  // prepare reply
+  MClientReply *reply = new MClientReply(req, 0);
 
-  dout(12) << "_do_open issued caps " << cap_string(cap->pending())
-          << " for " << req->get_source()
-          << " on " << *cur << dendl;
+  if (mdr->ref_snapid == CEPH_NOSNAP) {
+    // register new cap
+    bool is_new = false;
+    Capability *cap = mds->locker->issue_new_caps(cur, cmode, mdr->session, is_new);
+    
+    // drop our locks (they may interfere with us issuing new caps)
+    mdcache->request_drop_locks(mdr);
+    
+    if (is_new)
+      cap->dec_suppress();  // stop suppressing messages on new cap
+    
+    dout(12) << "_do_open issued caps " << cap_string(cap->pending())
+            << " for " << req->get_orig_source()
+            << " on " << *cur << dendl;
+
+    reply->set_file_caps(cap->pending());
+    reply->set_file_caps_seq(cap->get_last_seq());
+    reply->set_file_caps_mseq(cap->get_mseq());
+
+    // make sure this inode gets into the journal
+    if (!cur->xlist_open_file.is_on_xlist()) {
+      LogSegment *ls = mds->mdlog->get_current_segment();
+      EOpen *le = new EOpen(mds->mdlog);
+      le->add_clean_inode(cur);
+      ls->open_files.push_back(&cur->xlist_open_file);
+      mds->mdlog->submit_entry(le);
+    }
+  } else {
+    int caps = ceph_caps_for_mode(cmode);
+    dout(12) << "_do_open issued IMMUTABLE SNAP caps " << cap_string(caps)
+            << " for " << req->get_orig_source()
+            << " snapid " << mdr->ref_snapid
+            << " on " << *cur << dendl;
+    reply->set_file_caps(caps);
+  }
   
   // hit pop
   mdr->now = g_clock.now();
@@ -4604,28 +4638,13 @@ void Server::_do_open(MDRequest *mdr, CInode *cur)
   else
     mds->balancer->hit_inode(mdr->now, cur, META_POP_IRD, 
                             mdr->client_request->get_orig_source().num());
-
-  // reply
-  MClientReply *reply = new MClientReply(req, 0);
-  reply->set_file_caps(cap->pending());
-  reply->set_file_caps_seq(cap->get_last_seq());
-  reply->set_file_caps_mseq(cap->get_mseq());
-
+  
   SnapRealm *realm = cur->find_snaprealm();
   realm->build_snap_trace(reply->snapbl);
   dout(10) << " snaprealm is " << *realm << " on " << *realm->inode << dendl;
-  
+
   //reply->set_file_data_version(fdv);
   reply_request(mdr, reply);
-
-  // make sure this inode gets into the journal
-  if (!cur->xlist_open_file.is_on_xlist()) {
-    LogSegment *ls = mds->mdlog->get_current_segment();
-    EOpen *le = new EOpen(mds->mdlog);
-    le->add_clean_inode(cur);
-    ls->open_files.push_back(&cur->xlist_open_file);
-    mds->mdlog->submit_entry(le);
-  }
 }
 
 
@@ -4738,6 +4757,7 @@ public:
 
     // set/pin ref inode for open()
     mdr->ref = newi;
+    mdr->ref_snapid = CEPH_NOSNAP;
     mdr->pin(newi);
     mdr->trace.push_back(dn);