From: Sage Weil <sage@newdream.net>
Date: Wed, 28 Jul 2010 21:57:11 +0000 (-0700)
Subject: filestore: fix fallback clone_range implementation on short files
X-Git-Tag: v0.21~16
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=eb1f58743a4d183bd3a47c18a301b0d48c19f276;p=ceph.git

filestore: fix fallback clone_range implementation on short files

If we read less data from the source, don't loop forever... return -ERANGE
instead.
---

diff --git a/src/os/FileStore.cc b/src/os/FileStore.cc
index cb88b36ae91a..f76e84856efb 100644
--- a/src/os/FileStore.cc
+++ b/src/os/FileStore.cc
@@ -1516,19 +1516,32 @@ int FileStore::_do_clone_range(int from, int to, uint64_t off, uint64_t len)
   while (pos < end) {
     int l = MIN(end-pos, buflen);
     r = ::read(from, buf, l);
+    dout(25) << "  read from " << from << "~" << l << " got " << r << dendl;
     if (r < 0)
       break;
+    if (r == 0) {
+      // hrm, bad source range, wtf.
+      dout(0) << "_do_clone_range got short read result at " << from << " of " << from << "~" << len << dendl;
+      r = -ERANGE;
+      break;
+    }
     int op = 0;
-    while (op < l) {
-      int r2 = ::write(to, buf+op, l-op);
-      
-      if (r2 < 0) { r = r2; break; }
-      op += r2;	  
+    while (op < r) {
+      int r2 = ::write(to, buf+op, r-op);
+      dout(25) << " write to " << to << "~" << (r-op) << " got " << r2 << dendl;      
+      if (r2 < 0) {
+	r = r2;
+	break;
+      }
+      op += r2;
     }
-    if (r < 0) break;
+    if (r < 0)
+      break;
     pos += r;
   }
-
+  if (r < 0)
+    r = -errno;
+  dout(20) << "_do_clone_range " << off << "~" << len << " = " << r << dendl;
   return r;
 }