From ab44e5971f14b88102921b06edaa671bbb117b5d Mon Sep 17 00:00:00 2001
From: "Yan, Zheng" <zyan@redhat.com>
Date: Fri, 10 Apr 2015 13:58:15 +0800
Subject: [PATCH] mds: make sure snap inode's last match existing snapshots

MDCache::pick_inode_snap() and snap caps flushing code require
this.

Signed-off-by: Yan, Zheng <zyan@redhat.com>
---
 src/mds/CInode.cc  | 12 ++++++++----
 src/mds/MDCache.cc | 21 ++++++++++++++++-----
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/src/mds/CInode.cc b/src/mds/CInode.cc
index 38ecb1615305f..b5507d3b923a8 100644
--- a/src/mds/CInode.cc
+++ b/src/mds/CInode.cc
@@ -304,10 +304,14 @@ void CInode::split_need_snapflush(CInode *cowin, CInode *in)
 {
   dout(10) << "split_need_snapflush [" << cowin->first << "," << cowin->last << "] for " << *cowin << dendl;
   for (compact_map<snapid_t, set<client_t> >::iterator p = client_need_snapflush.lower_bound(cowin->first);
-       p != client_need_snapflush.end() && p->first <= cowin->last;
-       ++p) {
-    assert(!p->second.empty());
-    cowin->auth_pin(this);
+       p != client_need_snapflush.end() && p->first < in->first; ) {
+    compact_map<snapid_t, set<client_t> >::iterator q = p;
+    ++p;
+    assert(!q->second.empty());
+    if (cowin->last >= q->first)
+      cowin->auth_pin(this);
+    else
+      client_need_snapflush.erase(q);
     in->auth_unpin(this);
   }
 }
diff --git a/src/mds/MDCache.cc b/src/mds/MDCache.cc
index f9e5a48e85c33..041c691b3a3ad 100644
--- a/src/mds/MDCache.cc
+++ b/src/mds/MDCache.cc
@@ -1482,11 +1482,25 @@ CInode *MDCache::cow_inode(CInode *in, snapid_t last)
 {
   assert(last >= in->first);
 
-  CInode *oldin = new CInode(this, true, in->first, last);
+  SnapRealm *realm = in->find_snaprealm();
+  const set<snapid_t>& snaps = realm->get_snaps();
+
+  // make sure snap inode's last match existing snapshots.
+  // MDCache::pick_inode_snap() requires this.
+  snapid_t last_snap = last;
+  if (snaps.count(last) == 0) {
+    set<snapid_t>::const_iterator p = snaps.upper_bound(last);
+    if (p != snaps.begin()) {
+      --p;
+      if (*p >= in->first)
+	last_snap = *p;
+    }
+  }
+
+  CInode *oldin = new CInode(this, true, in->first, last_snap);
   oldin->inode = *in->get_previous_projected_inode();
   oldin->symlink = in->symlink;
   oldin->xattrs = *in->get_previous_projected_xattrs();
-
   oldin->inode.trim_client_ranges(last);
 
   if (in->first < in->oldest_snap)
@@ -1496,9 +1510,6 @@ CInode *MDCache::cow_inode(CInode *in, snapid_t last)
 
   dout(10) << "cow_inode " << *in << " to " << *oldin << dendl;
   add_inode(oldin);
-  
-  SnapRealm *realm = in->find_snaprealm();
-  const set<snapid_t>& snaps = realm->get_snaps();
 
   if (in->last != CEPH_NOSNAP) {
     CInode *head_in = get_inode(in->ino());
-- 
2.39.5