mds: include requested caps (namely, xattrs) on getattr reply

For xattrs, we only include them in the reply if we are issuing caps on
them.  However, in the getattr case, we need to include the snapshot of the
current state.

The original problem is reproduced by LibCephFS.Xattrs_ll (a simple set
then get).

Signed-off-by: Sage Weil <sage@inktank.com>

4 files changed, 16 insertions, 5 deletions

diff --git a/src/mds/CInode.cc b/src/mds/CInode.cc
index 7accc5a4dba..4a45d7ac0b1 100644
--- a/src/mds/CInode.cc
+++ b/src/mds/CInode.cc
@@ -2728,8 +2728,10 @@ void CInode::replicate_relax_locks()
 // =============================================
 
 int CInode::encode_inodestat(bufferlist& bl, Session *session,
-			      SnapRealm *dir_realm,
-			      snapid_t snapid, unsigned max_bytes)
+			     SnapRealm *dir_realm,
+			     snapid_t snapid,
+			     unsigned max_bytes,
+			     int getattr_caps)
 {
   int client = session->info.inst.name.num();
   assert(snapid);
@@ -2939,7 +2941,7 @@ int CInode::encode_inodestat(bufferlist& bl, Session *session,
 
   // include those xattrs?
   if (xbl.length() && cap) {
-    if (cap->pending() & CEPH_CAP_XATTR_SHARED) {
+    if ((cap->pending() | getattr_caps) & CEPH_CAP_XATTR_SHARED) {
       dout(10) << "including xattrs version " << i->xattr_version << dendl;
       cap->client_xattr_version = i->xattr_version;
     } else {
diff --git a/src/mds/CInode.h b/src/mds/CInode.h
index 1c2a9339c1c..d130b1e5480 100644
--- a/src/mds/CInode.h
+++ b/src/mds/CInode.h
@@ -599,7 +599,8 @@ private:
 
   // for giving to clients
   int encode_inodestat(bufferlist& bl, Session *session, SnapRealm *realm,
-		       snapid_t snapid=CEPH_NOSNAP, unsigned max_bytes=0);
+		       snapid_t snapid=CEPH_NOSNAP, unsigned max_bytes=0,
+		       int getattr_wants=0);
   void encode_cap_message(MClientCaps *m, Capability *cap);
 
 
diff --git a/src/mds/Mutation.h b/src/mds/Mutation.h
index b50a03cefa4..94e29fce434 100644
--- a/src/mds/Mutation.h
+++ b/src/mds/Mutation.h
@@ -178,6 +178,7 @@ struct MDRequest : public Mutation {
   int snap_caps;
   bool did_early_reply;
   bool o_trunc;           ///< request is an O_TRUNC mutation
+  int getattr_caps;       ///< caps requested by getattr
 
   bufferlist reply_extra_bl;
 
@@ -250,6 +251,7 @@ struct MDRequest : public Mutation {
     client_request(0), straydn(NULL), snapid(CEPH_NOSNAP), tracei(0), tracedn(0),
     alloc_ino(0), used_prealloc_ino(0), snap_caps(0), did_early_reply(false),
     o_trunc(false),
+    getattr_caps(0),
     slave_request(0),
     internal_op(-1),
     retry(0),
@@ -264,6 +266,7 @@ struct MDRequest : public Mutation {
     client_request(req), straydn(NULL), snapid(CEPH_NOSNAP), tracei(0), tracedn(0),
     alloc_ino(0), used_prealloc_ino(0), snap_caps(0), did_early_reply(false),
     o_trunc(false),
+    getattr_caps(0),
     slave_request(0),
     internal_op(-1),
     retry(0),
@@ -278,6 +281,7 @@ struct MDRequest : public Mutation {
     client_request(0), straydn(NULL), snapid(CEPH_NOSNAP), tracei(0), tracedn(0),
     alloc_ino(0), used_prealloc_ino(0), snap_caps(0), did_early_reply(false),
     o_trunc(false),
+    getattr_caps(0),
     slave_request(0),
     internal_op(-1),
     retry(0),
diff --git a/src/mds/Server.cc b/src/mds/Server.cc
index bb854f3045f..bf0fcd1e089 100644
--- a/src/mds/Server.cc
+++ b/src/mds/Server.cc
@@ -1034,7 +1034,7 @@ void Server::set_trace_dist(Session *session, MClientReply *reply,
 
   // inode
   if (in) {
-    in->encode_inodestat(bl, session, NULL, snapid);
+    in->encode_inodestat(bl, session, NULL, snapid, 0, mdr->getattr_caps);
     dout(20) << "set_trace_dist added in   " << *in << dendl;
     reply->head.is_target = 1;
   } else
@@ -2282,6 +2282,10 @@ void Server::handle_client_getattr(MDRequest *mdr, bool is_lookup)
   if (!mds->locker->acquire_locks(mdr, rdlocks, wrlocks, xlocks))
     return;
 
+  // note which caps are requested, so we return at least a snapshot
+  // value for them.  (currently this only matters for xattrs)
+  mdr->getattr_caps = mask;
+
   mds->balancer->hit_inode(ceph_clock_now(g_ceph_context), ref, META_POP_IRD,
 			   mdr->client_request->get_source().num());