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>

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 6c662598f8857fafe0be6371749bd73316fa895e..99a4f52c14b2b0887f15decb009b6a0d44140bf6 100644 (file)
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1045,6 +1045,51 @@ struct nfs_fh *nfs_alloc_fhandle(void)
        return fh;
 }
 
+/**
+ * _nfs_display_fhandle - display an NFS file handle on the console
+ *
+ * @fh: file handle to display
+ * @caption: display caption
+ *
+ * For debugging only.
+ */
+#ifdef RPC_DEBUG
+void _nfs_display_fhandle(const struct nfs_fh *fh, const char *caption)
+{
+       unsigned short i;
+
+       if (fh->size == 0 || fh == NULL) {
+               printk(KERN_DEFAULT "%s at %p is empty\n", caption, fh);
+               return;
+       }
+
+       printk(KERN_DEFAULT "%s at %p is %u bytes:\n", caption, fh, fh->size);
+       for (i = 0; i < fh->size; i += 16) {
+               __be32 *pos = (__be32 *)&fh->data[i];
+
+               switch ((fh->size - i - 1) >> 2) {
+               case 0:
+                       printk(KERN_DEFAULT " %08x\n",
+                               be32_to_cpup(pos));
+                       break;
+               case 1:
+                       printk(KERN_DEFAULT " %08x %08x\n",
+                               be32_to_cpup(pos), be32_to_cpup(pos + 1));
+                       break;
+               case 2:
+                       printk(KERN_DEFAULT " %08x %08x %08x\n",
+                               be32_to_cpup(pos), be32_to_cpup(pos + 1),
+                               be32_to_cpup(pos + 2));
+                       break;
+               default:
+                       printk(KERN_DEFAULT " %08x %08x %08x %08x\n",
+                               be32_to_cpup(pos), be32_to_cpup(pos + 1),
+                               be32_to_cpup(pos + 2), be32_to_cpup(pos + 3));
+               }
+       }
+}
+#endif
+
 /**
  * nfs_inode_attrs_need_update - check if the inode attributes need updating
  * @inode - pointer to inode

diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 8c29950d2fa5041497c22614808f682e76b3681c..c07a757649dc9739d7fc945233e8d7df03dfc266 100644 (file)
--- 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
  */