[PATCH] knfsd: nfsd4: reboot hash

For the purposes of reboot recovery we keep a directory with subdirectories
each having a name that is the ascii hex representation of the md5 sum of a
client identifier for an active client.

This adds the code to calculate that name.  We also use it for the purposes of
comparing clients, so if someone ever manages to find two client names that
are md5 collisions, then we'll return clid_inuse to the second.

Signed-off-by: Andy Adamson <andros@citi.umich.edu>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 97 insertions, 0 deletions

diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
new file mode 100644
index 000000000000..841a305d7948
--- /dev/null
+++ b/fs/nfsd/nfs4recover.c
@@ -0,0 +1,97 @@
+/*
+*  linux/fs/nfsd/nfs4recover.c
+*
+*  Copyright (c) 2004 The Regents of the University of Michigan.
+*  All rights reserved.
+*
+*  Andy Adamson <andros@citi.umich.edu>
+*
+*  Redistribution and use in source and binary forms, with or without
+*  modification, are permitted provided that the following conditions
+*  are met:
+*
+*  1. Redistributions of source code must retain the above copyright
+*     notice, this list of conditions and the following disclaimer.
+*  2. Redistributions in binary form must reproduce the above copyright
+*     notice, this list of conditions and the following disclaimer in the
+*     documentation and/or other materials provided with the distribution.
+*  3. Neither the name of the University nor the names of its
+*     contributors may be used to endorse or promote products derived
+*     from this software without specific prior written permission.
+*
+*  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+*  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+*  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+*  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+*  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+*  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+*  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+*  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+*  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+*  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+*  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+*/
+
+
+#include <linux/sunrpc/svc.h>
+#include <linux/nfsd/nfsd.h>
+#include <linux/nfs4.h>
+#include <linux/nfsd/state.h>
+#include <linux/nfsd/xdr4.h>
+#include <asm/uaccess.h>
+#include <asm/scatterlist.h>
+#include <linux/crypto.h>
+
+
+#define NFSDDBG_FACILITY                NFSDDBG_PROC
+
+static void
+md5_to_hex(char *out, char *md5)
+{
+        int i;
+
+        for (i=0; i<16; i++) {
+                unsigned char c = md5[i];
+
+                *out++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
+                *out++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
+        }
+        *out = '\0';
+}
+
+int
+nfs4_make_rec_clidname(char *dname, struct xdr_netobj *clname)
+{
+        struct xdr_netobj cksum;
+        struct crypto_tfm *tfm;
+        struct scatterlist sg[1];
+        int status = nfserr_resource;
+
+        dprintk("NFSD: nfs4_make_rec_clidname for %.*s\n",
+                        clname->len, clname->data);
+        tfm = crypto_alloc_tfm("md5", 0);
+        if (tfm == NULL)
+                goto out;
+        cksum.len = crypto_tfm_alg_digestsize(tfm);
+        cksum.data = kmalloc(cksum.len, GFP_KERNEL);
+        if (cksum.data == NULL)
+                goto out;
+        crypto_digest_init(tfm);
+
+        sg[0].page = virt_to_page(clname->data);
+        sg[0].offset = offset_in_page(clname->data);
+        sg[0].length = clname->len;
+
+        crypto_digest_update(tfm, sg, 1);
+        crypto_digest_final(tfm, cksum.data);
+
+        md5_to_hex(dname, cksum.data);
+
+        kfree(cksum.data);
+        status = nfs_ok;
+out:
+        if (tfm)
+                crypto_free_tfm(tfm);
+        return status;
+}