From 1264a2f053a32376696e51184f086d35113e75ff Mon Sep 17 00:00:00 2001
From: Trond Myklebust <Trond.Myklebust@netapp.com>
Date: Mon, 12 Aug 2013 16:06:31 -0400
Subject: [PATCH] NFS: refactor code for calculating the crc32 hash of a
filehandle
We want to be able to display the crc32 hash of the filehandle in
tracepoints.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
---
fs/nfs/inode.c | 3 +--
fs/nfs/internal.h | 20 ++++++++++++++++++++
2 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index af6e806044d7..9a98b04c4445 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -38,7 +38,6 @@
#include <linux/slab.h>
#include <linux/compat.h>
#include <linux/freezer.h>
-#include <linux/crc32.h>
#include <asm/uaccess.h>
@@ -1190,7 +1189,7 @@ u32 _nfs_display_fhandle_hash(const struct nfs_fh *fh)
{
/* wireshark uses 32-bit AUTODIN crc and does a bitwise
* not on the result */
- return ~crc32(0xFFFFFFFF, &fh->data[0], fh->size);
+ return nfs_fhandle_hash(fh);
}
/*
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 9b694f1e06c5..50f7068903b9 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -5,6 +5,7 @@
#include "nfs4_fs.h"
#include <linux/mount.h>
#include <linux/security.h>
+#include <linux/crc32.h>
#define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS)
@@ -574,3 +575,22 @@ u64 nfs_timespec_to_change_attr(const struct timespec *ts)
{
return ((u64)ts->tv_sec << 30) + ts->tv_nsec;
}
+
+#ifdef CONFIG_CRC32
+/**
+ * nfs_fhandle_hash - calculate the crc32 hash for the filehandle
+ * @fh - pointer to filehandle
+ *
+ * returns a crc32 hash for the filehandle that is compatible with
+ * the one displayed by "wireshark".
+ */
+static inline u32 nfs_fhandle_hash(const struct nfs_fh *fh)
+{
+ return ~crc32_le(0xFFFFFFFF, &fh->data[0], fh->size);
+}
+#else
+static inline u32 nfs_fhandle_hash(const struct nfs_fh *fh)
+{
+ return 0;
+}
+#endif
--
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