cls_rbd: add failure logging to all callers of read_key.

Previously, read_key was printing out error messages when it failed.
But because some callers are fine with it failing on ENOENT, and they
all have more context anyway, it no longer does so and they need
their own logging output. Now they have it.

Signed-off-by: Greg Farnum <greg@inktank.com>

diff --git a/src/cls_rbd.cc b/src/cls_rbd.cc
index 957d7a6e532d1cb2d7506d6b27a18b7d8b9c834e..d01734909242e21f2fbb0bd2f433bfc66ed0ea83 100644 (file)
--- a/src/cls_rbd.cc
+++ b/src/cls_rbd.cc
@@ -291,8 +291,10 @@ int get_features(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
 
   if (snap_id == CEPH_NOSNAP) {
     int r = read_key(hctx, "features", &features);
-    if (r < 0)
+    if (r < 0) {
+      CLS_ERR("failed to read features off disk: %s", strerror(r));
       return r;
+    }
   } else {
     cls_rbd_snap snap;
     int r = read_snapshot_metadata(hctx, snap_id, &snap);
@@ -333,13 +335,17 @@ int get_size(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
   CLS_LOG(20, "get_size snap_id=%llu", snap_id);
 
   int r = read_key(hctx, "order", &order);
-  if (r < 0)
+  if (r < 0) {
+    CLS_ERR("failed to read the order off of disk: %s", strerror(r));
     return r;
+  }
 
   if (snap_id == CEPH_NOSNAP) {
     r = read_key(hctx, "size", &size);
-    if (r < 0)
+    if (r < 0) {
+      CLS_ERR("failed to read the image's size off of disk: %s", strerror(r));
       return r;
+    }
   } else {
     cls_rbd_snap snap;
     int r = read_snapshot_metadata(hctx, snap_id, &snap);
@@ -379,8 +385,10 @@ int set_size(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
   // that was created correctly
   uint64_t orig_size;
   int r = read_key(hctx, "size", &orig_size);
-  if (r < 0)
+  if (r < 0) {
+    CLS_ERR("Could not read image's size off disk: %s", strerror(r));
     return r;
+  }
 
   bufferlist sizebl;
   ::encode(size, sizebl);
@@ -412,7 +420,7 @@ int lock_image(cls_method_context_t hctx, string lock_type,
   string existing_lock_type;
   int r = read_key(hctx, RBD_LOCKS_KEY, &lockers);
   if (r != 0 && r != -ENOENT) {
-    CLS_ERR("Could not read list of current lockers");
+    CLS_ERR("Could not read list of current lockers: %s", strerror(r));
     return r;
   }
   if (exclusive && r != -ENOENT && lockers.size()) {
@@ -423,7 +431,7 @@ int lock_image(cls_method_context_t hctx, string lock_type,
     // make sure existing lock is a shared lock
     r = read_key(hctx, RBD_LOCK_TYPE_KEY, &existing_lock_type);
     if (r != 0) {
-      CLS_ERR("Could not read type of current locks");
+      CLS_ERR("Could not read type of current locks off disk: %s", strerror(r));
       return r;
     }
     if (existing_lock_type != lock_type) {
@@ -516,7 +524,7 @@ int remove_lock(cls_method_context_t hctx, const string& inst,
   string location = RBD_LOCKS_KEY;
   int r = read_key(hctx, location, &lockers);
   if (r != 0) {
-    CLS_ERR("Could not read list of current lockers");
+    CLS_ERR("Could not read list of current lockers off disk: %s", strerror(r));
     return r;
   }
 
@@ -609,7 +617,7 @@ int list_locks(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
   bool have_locks = true;
   int r = cls_cxx_map_get_val(hctx, key, out);
   if (r != 0 && r != -ENOENT) {
-    CLS_ERR("Failure in reading list of current lockers");
+    CLS_ERR("Failure in reading list of current lockers: %s", strerror(r));
     return r;
   }
   if (r == -ENOENT) { // none listed
@@ -621,6 +629,9 @@ int list_locks(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
   if (have_locks) {
     key = RBD_LOCK_TYPE_KEY;
     r = read_key(hctx, key, &exclusive_string);
+    if (r < 0) {
+      CLS_ERR("Failed to read lock type off disk: %s", strerror(r));
+    }
   }
   ::encode((exclusive_string == RBD_LOCK_EXCLUSIVE), *out);
   return r;
@@ -661,8 +672,10 @@ int get_snapcontext(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
 
   uint64_t snap_seq;
   r = read_key(hctx, "snap_seq", &snap_seq);
-  if (r < 0)
+  if (r < 0) {
+    CLS_ERR("could not read the image's snap_seq off disk: %s", strerror(r));
     return r;
+  }
 
   // snap_ids must be descending in a snap context
   std::reverse(snap_ids.begin(), snap_ids.end());
@@ -684,8 +697,11 @@ int get_object_prefix(cls_method_context_t hctx, bufferlist *in, bufferlist *out
 
   string object_prefix;
   int r = read_key(hctx, "object_prefix", &object_prefix);
-  if (r < 0)
+  if (r < 0) {
+    CLS_ERR("failed to read the image's object prefix off of disk: %s",
+            strerror(r));
     return r;
+  }
 
   ::encode(object_prefix, *out);
 
@@ -751,8 +767,10 @@ int snapshot_add(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
 
   uint64_t cur_snap_seq;
   int r = read_key(hctx, "snap_seq", &cur_snap_seq);
-  if (r < 0)
+  if (r < 0) {
+    CLS_ERR("Could not read image's snap_seq off disk: %s", strerror(r));
     return r;
+  }
 
   // client lost a race with another snapshot creation.
   // snap_seq must be monotonically increasing.
@@ -761,12 +779,16 @@ int snapshot_add(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
 
   uint64_t size;
   r = read_key(hctx, "size", &size);
-  if (r < 0)
+  if (r < 0) {
+    CLS_ERR("Could not read image's size off disk: %s", strerror(r));
     return r;
+  }
   uint64_t features;
   r = read_key(hctx, "features", &features);
-  if (r < 0)
+  if (r < 0) {
+    CLS_ERR("Could not read image's features off disk: %s", strerror(r));
     return r;
+  }
 
   int max_read = RBD_MAX_KEYS_READ;
   string last_read = RBD_SNAP_KEY_PREFIX;