7060790: (fs) FileSystem.newWatchService error message confusing when maximum inotify descriptors reached

Reviewed-by: forax

jdk/src/solaris/classes/sun/nio/fs/LinuxWatchService.java

@@ -58,7 +58,10 @@ class LinuxWatchService
         try {
             ifd = inotifyInit();
         } catch (UnixException x) {
-            throw new IOException(x.errorString());
+            String msg = (x.errno() == EMFILE) ?
+                "User limit of inotify instances reached or too many open files" :
+                x.errorString();
+            throw new IOException(msg);
         }
 
         // configure inotify to be non-blocking

jdk/src/solaris/native/sun/nio/fs/genUnixConstants.c

@@ -108,6 +108,7 @@ int main(int argc, const char* argv[]) {
     DEF(EROFS);
     DEF(ENODATA);
     DEF(ERANGE);
+    DEF(EMFILE);
 
     // flags used with openat/unlinkat/etc.
 #if defined(AT_SYMLINK_NOFOLLOW) && defined(AT_REMOVEDIR)