From 534e706b61114bbb6a462c0b9c911d42a1498f23 Mon Sep 17 00:00:00 2001
From: "Brian J. Murrell" <brian.murrell@oracle.com>
Date: Thu, 18 Nov 2010 02:27:17 +0800
Subject: [PATCH 1/1] b=24089 avoid reuse cache storage collisions

This is a hack.  Basically, all nodes do their build and the last one
to store in the cache wins.
A better solution would be for nodes to announce their intention to
build for a given hash and any other nodes that will do the same wait
for the first node to finish and store it.  Subsequent nodes then just
use the first node's stored result.

i=wangyb
i=cliff
---
 build/lbuild | 85 +++++++++++++++++++++++++++++++++++-------------------------
 1 file changed, 50 insertions(+), 35 deletions(-)

diff --git a/build/lbuild b/build/lbuild
index f18a5a3..3f4e5cd 100755
--- a/build/lbuild
+++ b/build/lbuild
@@ -1103,45 +1103,60 @@ EOF
 }
 
 store_for_reuse() {
-        local articles="$1"
-        local module="$2"
-        local location="$3"
-        local signature="$4"
-        local use_links="$5"
+    local articles="$1"
+    local module="$2"
+    local location="$3"
+    local signature="$4"
+    local use_links="$5"
 
-        local linkflag=""
-        if $use_links; then
-            linkflag="l"
-        fi
+    local linkflag=""
+    if $use_links; then
+        linkflag="l"
+    fi
 
-        location="$location"/"$signature"/"$module"
-        mkdir -p "$location"
-        # the cleanup script removes any directory that doesn't have a
-        # .lastused, so let's try to prevent that as soon as we can
-        # this solution still slightly racy with the cleanup script
-        # but the race is a lot tighter now
-        touch -t 197001010000 "$location/.lastused"
-        ## use eval/echo here to make sure shell expansions are performed
-        #if ! cp -a${linkflag} $(eval echo $articles) "$location"; then
-        local article
-        for article in $(eval echo $articles); do
-            if ! cp -a${linkflag} "$article" "$location"; then
-                error "Failed to copy \"$article\" to \"$location\" in store_for_reuse()"
-                # rename the cache location so that it's not cached
-                # product, but is around for analysis
-                mv "$location"{,-bad-$(date +%s)} ||
-                    error "failed to clean up a failed cache attempt" \
-                          "in \"$location\" -- manual cleanup will be" \
-                          "necessary"
-                return 1
-            fi
-        done
+    local default_iface=$(/sbin/ip route get 192.1.1.1 | sed -ne 's/.* dev \(.*\)  * src .*/\1/p')
+    if [ -z "$default_iface" ]; then
+        fatal 1 "Failed to determine the default route interface"
+    fi
+    local unique_id=$(/sbin/ip addr show dev $default_iface | sed -ne '/ inet /s/ *inet \(.*\)\/.*/\1/p' | head -1)
+    if [ -z "$unique_id" ]; then
+        fatal 1 "Failed to determine a unique id from interface $default_interface"
+    fi
 
-        # flag the cache as complete (i.e. in case lbuild was previously
-        # interrupted while caching)
-        touch "$location/.lastused"
+    local finallocation="$location"/"$signature"/"$module"
+    location="$location"/"$signature-${unique_id}"/"$module"
+    mkdir -p "$location"
+    # the cleanup script removes any directory that doesn't have a
+    # .lastused, so let's try to prevent that as soon as we can
+    # this solution still slightly racy with the cleanup script
+    # but the race is a lot tighter now
+    touch -t 197001010000 "$location/.lastused"
+    ## use eval/echo here to make sure shell expansions are performed
+    #if ! cp -a${linkflag} $(eval echo $articles) "$location"; then
+    local article
+    for article in $(eval echo $articles); do
+        if ! cp -a${linkflag} "$article" "$location"; then
+            error "Failed to copy \"$article\" to \"$location\" in store_for_reuse()"
+            # rename the cache location so that it's not cached
+            # product, but is around for analysis
+            mv "$location"{,-bad-$(date +%s)} ||
+                error "failed to clean up a failed cache attempt" \
+                      "in \"$location\" -- manual cleanup will be" \
+                      "necessary"
+            return 1
+        fi
+    done
 
-        return 0
+    # flag the cache as complete (i.e. in case lbuild was previously
+    # interrupted while caching)
+    touch "$location/.lastused"
+
+    # put the temporary location into the final location
+    # (last one wins)
+    mkdir -p "${finallocation%/*}"
+    mv "$location" "$finallocation"
+    rmdir "${location%/*}"
+    return 0
 
 }
 
-- 
1.8.3.1