From bc6559d62c21ee046c4082aba282097a8c1de9ac Mon Sep 17 00:00:00 2001
From: Simon Wilkinson <sxw@inf.ed.ac.uk>
Date: Sat, 26 Sep 2009 10:06:27 +0100
Subject: [PATCH] Attempt to fix CForeign moredata behaviour

The fetchstore patches changed the behaviour of the multiple chunk handling
that's used in FetchData when the vnode's CForeign bit is set. In the original
code, the data would be read as (length, payload) chunks. The new code does
(length, length, payload), which corrupts the incoming data.

This patch restores the original control flow.

Reviewed-on: http://gerrit.openafs.org/498
Tested-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
---
 src/afs/afs_fetchstore.c | 43 +++++++++++++---------------------------
 1 file changed, 14 insertions(+), 29 deletions(-)

diff --git a/src/afs/afs_fetchstore.c b/src/afs/afs_fetchstore.c
index 846fda0e2b..bd6f47c89b 100644
--- a/src/afs/afs_fetchstore.c
+++ b/src/afs/afs_fetchstore.c
@@ -819,7 +819,7 @@ rxfs_fetchDestroy(void **r, afs_int32 error)
 }
 
 afs_int32
-rxfs_fetchMore(void *r, afs_uint32 *length, afs_uint32 *moredata)
+rxfs_fetchMore(void *r, afs_int32 *length, afs_uint32 *moredata)
 {
     afs_int32 code;
     struct rxfs_fetchVariables *v = (struct rxfs_fetchVariables *)r;
@@ -833,14 +833,16 @@ rxfs_fetchMore(void *r, afs_uint32 *length, afs_uint32 *moredata)
      * We do not do this for AFS file servers because they sometimes
      * return large negative numbers as the transfer size.
      */
-    RX_AFS_GUNLOCK();
-    code = rx_Read(v->call, (void *)length, sizeof(afs_int32));
-    RX_AFS_GLOCK();
-    *length = ntohl(*length);
-    if (code != sizeof(afs_int32)) {
-	code = rx_Error(v->call);
-	*moredata = 0;
-	return (code ? code : -1);	/* try to return code, not -1 */
+    if (*moredata) {
+	RX_AFS_GUNLOCK();
+	code = rx_Read(v->call, (void *)length, sizeof(afs_int32));
+	RX_AFS_GLOCK();
+	*length = ntohl(*length);
+	if (code != sizeof(afs_int32)) {
+	    code = rx_Error(v->call);
+	    *moredata = 0;
+	    return (code ? code : -1);	/* try to return code, not -1 */
+        }
     }
     *moredata = *length & 0x80000000;
     *length &= ~0x80000000;
@@ -867,8 +869,7 @@ struct fetchOps rxfs_fetchMemOps = {
 
 afs_int32
 rxfs_fetchInit(struct afs_conn *tc, struct vcache *avc, afs_offs_t base,
-		afs_uint32 size, afs_int32 *alength, afs_uint32 *moredata,
-		struct dcache *adc,
+		afs_uint32 size, afs_int32 *alength, struct dcache *adc,
 		struct osi_file *fP, struct fetchOps **ops, void **rock)
 {
     struct rxfs_fetchVariables *v;
@@ -971,22 +972,6 @@ rxfs_fetchInit(struct afs_conn *tc, struct vcache *avc, afs_offs_t base,
 	osi_FreeSmallSpace(v);
         return code;
     }
-    /*
-     * The fetch protocol is extended for the AFS/DFS translator
-     * to allow multiple blocks of data, each with its own length,
-     * to be returned. As long as the top bit is set, there are more
-     * blocks expected.
-     *
-     * We do not do this for AFS file servers because they sometimes
-     * return large negative numbers as the transfer size.
-     *
-     * Also omit if length > 2^32, as bit 31 is part of the number then.
-     * Known to never be the case ifndef AFS_64BIT_CLIENT.
-     */
-    if (avc->f.states & CForeign && !length_hi) {
-	*moredata = length & 0x80000000;
-	length &= ~0x80000000;
-    }
     if (cacheDiskType == AFS_FCACHE_TYPE_UFS) {
 	v->tbuffer = osi_AllocLargeSpace(AFS_LRALLOCSIZ);
 	if (!v->tbuffer)
@@ -1057,7 +1042,7 @@ afs_CacheFetchProc(struct afs_conn *tc, struct osi_file *fP, afs_size_t base,
      * adc->lock(W)
      */
     code = rxfs_fetchInit(
-		tc, avc, base, size, &length, &moredata, adc, fP, &ops, &rock);
+		tc, avc, base, size, &length, adc, fP, &ops, &rock);
 
 #ifndef AFS_NOSTATS
     osi_GetuTime(&xferStartTime);
@@ -1068,7 +1053,7 @@ afs_CacheFetchProc(struct afs_conn *tc, struct osi_file *fP, afs_size_t base,
     }
 
     if ( !code ) do {
-	if ((avc->f.states & CForeign) && moredata && !length) {
+	if (avc->f.states & CForeign) {
 	    code = (*ops->more)(rock, &length, &moredata);
 	    if ( code )
 		break;