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authorWeston Andros Adamson <dros@netapp.com>2012-03-06 20:46:43 -0500
committerTrond Myklebust <Trond.Myklebust@netapp.com>2012-03-07 10:34:07 -0500
commitd8e0539ebdff5ff27fa7eb019715d9dfb5171a3b (patch)
treec85febe66a9527be703fd82fd9e017df740364b3
parentff2eb6818d0d5b2691c112f51c539a817fcc59fc (diff)
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NFS: add filehandle crc for debug display
Match wireshark's CRC-32 hash for easier debugging Signed-off-by: Weston Andros Adamson <dros@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
-rw-r--r--fs/nfs/inode.c23
-rw-r--r--include/linux/nfs_fs.h8
2 files changed, 28 insertions, 3 deletions
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index ba03b790814..0337554f156 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -39,6 +39,7 @@
#include <linux/slab.h>
#include <linux/compat.h>
#include <linux/freezer.h>
+#include <linux/crc32.h>
#include <asm/system.h>
#include <asm/uaccess.h>
@@ -1045,7 +1046,23 @@ struct nfs_fh *nfs_alloc_fhandle(void)
return fh;
}
-/**
+#ifdef RPC_DEBUG
+/*
+ * _nfs_display_fhandle_hash - calculate the crc32 hash for the filehandle
+ * in the same way that wireshark does
+ *
+ * @fh: file handle
+ *
+ * For debugging only.
+ */
+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);
+}
+
+/*
* _nfs_display_fhandle - display an NFS file handle on the console
*
* @fh: file handle to display
@@ -1053,7 +1070,6 @@ struct nfs_fh *nfs_alloc_fhandle(void)
*
* For debugging only.
*/
-#ifdef RPC_DEBUG
void _nfs_display_fhandle(const struct nfs_fh *fh, const char *caption)
{
unsigned short i;
@@ -1063,7 +1079,8 @@ void _nfs_display_fhandle(const struct nfs_fh *fh, const char *caption)
return;
}
- printk(KERN_DEFAULT "%s at %p is %u bytes:\n", caption, fh, fh->size);
+ printk(KERN_DEFAULT "%s at %p is %u bytes, crc: 0x%08x:\n",
+ caption, fh, fh->size, _nfs_display_fhandle_hash(fh));
for (i = 0; i < fh->size; i += 16) {
__be32 *pos = (__be32 *)&fh->data[i];
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index c07a757649d..ce8e4361ad1 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -396,6 +396,11 @@ static inline void nfs_free_fhandle(const struct nfs_fh *fh)
}
#ifdef RPC_DEBUG
+extern u32 _nfs_display_fhandle_hash(const struct nfs_fh *fh);
+static inline u32 nfs_display_fhandle_hash(const struct nfs_fh *fh)
+{
+ return _nfs_display_fhandle_hash(fh);
+}
extern void _nfs_display_fhandle(const struct nfs_fh *fh, const char *caption);
#define nfs_display_fhandle(fh, caption) \
do { \
@@ -403,6 +408,9 @@ extern void _nfs_display_fhandle(const struct nfs_fh *fh, const char *caption);
_nfs_display_fhandle(fh, caption); \
} while (0)
#else
+static inline u32 nfs_display_fhandle_hash(const struct nfs_fh *fh)
+{
+}
static inline void nfs_display_fhandle(const struct nfs_fh *fh,
const char *caption)
{