NFS: Add a client-side function to display NFS file handles

For debugging, introduce a simplistic function to print NFS file
handles on the system console.  The main function is hooked into the
dprintk debugging facility, but you can directly call the helper,
_nfs_display_fhandle(), if you want to print a handle unconditionally.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 8c29950d2fa5..c07a757649dc 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -395,6 +395,20 @@ static inline void nfs_free_fhandle(const struct nfs_fh *fh)
         kfree(fh);
 }
 
+#ifdef RPC_DEBUG
+extern void _nfs_display_fhandle(const struct nfs_fh *fh, const char *caption);
+#define nfs_display_fhandle(fh, caption)                        \
+        do {                                                    \
+                if (unlikely(nfs_debug & NFSDBG_FACILITY))      \
+                        _nfs_display_fhandle(fh, caption);      \
+        } while (0)
+#else
+static inline void nfs_display_fhandle(const struct nfs_fh *fh,
+                                       const char *caption)
+{
+}
+#endif
+
 /*
  * linux/fs/nfs/nfsroot.c
  */