From: Josh Durgin <josh.durgin@inktank.com>
Date: Thu, 24 Apr 2014 21:43:35 +0000 (-0700)
Subject: librbd: check return code and error out if invalidate_cache fails
X-Git-Tag: v0.67.10~4
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=d93579514db74eed61580a6166c2787304a8a9fb;p=ceph.git

librbd: check return code and error out if invalidate_cache fails

This will only happen when shrinking or rolling back an image is done
while other I/O is in flight to the same ImageCtx. This is unsafe, so
return an error before performing the resize or rollback.

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
(cherry picked from commit e08b8b66c77be3a3d7f79d91c20b1619571149ee)
---

diff --git a/src/librbd/ImageCtx.cc b/src/librbd/ImageCtx.cc
index 41518b67698..025e5602c81 100644
--- a/src/librbd/ImageCtx.cc
+++ b/src/librbd/ImageCtx.cc
@@ -568,9 +568,9 @@ namespace librbd {
     object_cacher->stop();
   }
 
-  void ImageCtx::invalidate_cache() {
+  int ImageCtx::invalidate_cache() {
     if (!object_cacher)
-      return;
+      return 0;
     cache_lock.Lock();
     object_cacher->release_set(object_set);
     cache_lock.Unlock();
@@ -580,8 +580,12 @@ namespace librbd {
     cache_lock.Lock();
     bool unclean = object_cacher->release_set(object_set);
     cache_lock.Unlock();
-    if (unclean)
-      lderr(cct) << "could not release all objects from cache" << dendl;
+    if (unclean) {
+      lderr(cct) << "could not release all objects from cache: "
+		 << unclean << " bytes remain" << dendl;
+      return -EBUSY;
+    }
+    return r;
   }
 
   void ImageCtx::clear_nonexistence_cache() {
diff --git a/src/librbd/ImageCtx.h b/src/librbd/ImageCtx.h
index 29ca2f197ea..db4092463ff 100644
--- a/src/librbd/ImageCtx.h
+++ b/src/librbd/ImageCtx.h
@@ -136,7 +136,7 @@ namespace librbd {
     void flush_cache_aio(Context *onfinish);
     int flush_cache();
     void shutdown_cache();
-    void invalidate_cache();
+    int invalidate_cache();
     void clear_nonexistence_cache();
     int register_watch();
     void unregister_watch();
diff --git a/src/librbd/internal.cc b/src/librbd/internal.cc
index 68a9e571d2b..55d910ea2ba 100644
--- a/src/librbd/internal.cc
+++ b/src/librbd/internal.cc
@@ -1498,7 +1498,9 @@ reprotect_and_return_err:
     if (size < ictx->size && ictx->object_cacher) {
       // need to invalidate since we're deleting objects, and
       // ObjectCacher doesn't track non-existent objects
-      ictx->invalidate_cache();
+      r = ictx->invalidate_cache();
+      if (r < 0)
+	return r;
     }
     resize_helper(ictx, size, prog_ctx);
 
@@ -1841,7 +1843,9 @@ reprotect_and_return_err:
     // need to flush any pending writes before resizing and rolling back -
     // writes might create new snapshots. Rolling back will replace
     // the current version, so we have to invalidate that too.
-    ictx->invalidate_cache();
+    r = ictx->invalidate_cache();
+    if (r < 0)
+      return r;
 
     ldout(cct, 2) << "resizing to snapshot size..." << dendl;
     NoOpProgressContext no_op;