rbd-nbd: warn when kernel parameters are ignored

Fixes: http://tracker.ceph.com/issues/19108
Signed-off-by: Pan Liu <liupan1111@gmail.com>

diff --git a/src/tools/rbd_nbd/rbd-nbd.cc b/src/tools/rbd_nbd/rbd-nbd.cc
index 89a86b3cec24ce6a85db26c973cfa64f7bc0d072..c09623708363ec366957509154b1d960864ee818 100644 (file)
--- a/src/tools/rbd_nbd/rbd-nbd.cc
+++ b/src/tools/rbd_nbd/rbd-nbd.cc
@@ -76,6 +76,7 @@ static std::string devpath, poolname("rbd"), imgname, snapname;
 static bool readonly = false;
 static int nbds_max = 0;
 static int max_part = 255;
+static bool set_max_part = false;
 static bool exclusive = false;
 
 #define RBD_NBD_BLKSIZE 512UL
@@ -452,6 +453,8 @@ public:
 static int open_device(const char* path, bool try_load_module = false)
 {
   int nbd = open(path, O_RDWR);
+  bool loaded_module = false;
+  
   if (nbd < 0 && try_load_module && access("/sys/module/nbd", F_OK) != 0) {
     ostringstream param;
     int r;
@@ -465,9 +468,18 @@ static int open_device(const char* path, bool try_load_module = false)
     if (r < 0) {
       cerr << "rbd-nbd: failed to load nbd kernel module: " << cpp_strerror(-r) << std::endl;
       return r;
+    } else {
+      loaded_module = true;
     }
     nbd = open(path, O_RDWR);
   }
+
+  if ((nbds_max || set_max_part) && 
+      try_load_module && !loaded_module) {
+    cerr << "rbd-nbd: ignoring kernel module parameter options: nbd module already loaded" 
+         << std::endl;
+  }
+  
   return nbd;
 }
 
@@ -823,6 +835,7 @@ static int rbd_nbd(int argc, const char *argv[])
         cerr << "rbd-nbd: Invalid argument for max_part(0~255)!" << std::endl;
         return EXIT_FAILURE;
       }
+      set_max_part = true;
     } else if (ceph_argparse_flag(args, i, "--read-only", (char *)NULL)) {
       readonly = true;
     } else if (ceph_argparse_flag(args, i, "--exclusive", (char *)NULL)) {