Attachment 927142 Details for Bug 1100080 – proof-of-concept patch

[patch] proof-of-concept patch

block_nonracy.patch (text/plain), 3.42 KB, created by Vitaly Kuznetsov on 2014-08-15 15:12:36 UTC

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Creator: Vitaly Kuznetsov

Created: 2014-08-15 15:12:36 UTC

Size: 3.42 KB

patch

obsolete

>--- block.old	2013-05-07 06:05:58.000000000 +0200
>+++ block.new	2014-08-15 17:12:13.000000000 +0200
>@@ -1,8 +1,23 @@
> #!/bin/sh
> 
>+claim_lock "block"
>+
> dir=$(dirname "$0")
> . "$dir/block-common.sh"
> 
>+fatal_releaselock() {
>+  xenstore_write "$XENBUS_PATH/hotplug-error" "$*" \
>+                 "$XENBUS_PATH/hotplug-status" error
>+  log err "$@"
>+  release_lock "block"
>+  exit 1
>+}
>+
>+exit0() {
>+  release_lock "block"
>+  exit 0
>+}
>+
> expand_dev() {
>   local dev
>   case $1 in
>@@ -201,7 +216,7 @@
>     then
>       # Depending upon the hotplug configuration, it is possible for this
>       # script to be called twice, so just bail.
>-      exit 0
>+      exit0
>     fi
> 
>     if [ -n "$t" ]
>@@ -216,29 +231,25 @@
>         FRONTEND_ID=$(xenstore_read "$XENBUS_PATH/frontend-id")
>         FRONTEND_UUID=$(xenstore_read_default \
>             "/local/domain/$FRONTEND_ID/vm" 'unknown')
>-        claim_lock "block"
>         check_device_sharing "$dev" "$mode"
> 	write_dev "$dev"
>         release_lock "block"
>-	exit 0
>+	exit0
> 	;;
> 
>       file)
>         # Canonicalise the file, for sharing check comparison, and the mode
>         # for ease of use here.
>-        file=$(readlink -f "$p") || fatal "$p does not exist."
>-        test -f "$file" || fatal "$file does not exist"
>+        file=$(readlink -f "$p") || fatal_releaselock "$p does not exist."
>+        test -f "$file" || fatal_releaselock "$file does not exist"
>         mode=$(canonicalise_mode "$mode")
> 
>-        claim_lock "block"
>-
>         # Avoid a race with the remove if the path has been deleted, or
> 	# otherwise changed from "InitWait" state e.g. due to a timeout
>         xenbus_state=$(xenstore_read_default "$XENBUS_PATH/state" 'unknown')
>         if [ "$xenbus_state" != '2' ]
>         then
>-          release_lock "block"
>-          fatal "Path closed or removed during hotplug add: $XENBUS_PATH state: $xenbus_state"
>+          fatal_releaselock "Path closed or removed during hotplug add: $XENBUS_PATH state: $xenbus_state"
>         fi
> 
>         if [ "$mode" == 'w' ] && ! stat "$file" -c %A | grep -q w
>@@ -255,7 +266,7 @@
>           dev=$(stat -c '%D' "$file")
>           if [ -z "$inode" ] || [ -z "$dev" ]
>           then
>-            fatal "Unable to lookup $file: dev: $dev inode: $inode"
>+            fatal_releaselock "Unable to lookup $file: dev: $dev inode: $inode"
>           fi
> 
>           shared_list=$(losetup -a | grep ' \[0*'${dev}'\]:'${inode} |
>@@ -272,7 +283,7 @@
>         loopdev=$(losetup -f)
>         if [ "$loopdev" == '' ]
>         then
>-          fatal 'Failed to find an unused loop device'
>+          fatal_releaselock 'Failed to find an unused loop device'
>         fi
> 
>         cmode=`canonicalise_mode $mode`
>@@ -285,11 +296,10 @@
>         xenstore_write "$XENBUS_PATH/node" "$loopdev"
>         write_dev "$loopdev"
>         release_lock "block"
>-        exit 0
>+        exit0
> 	;;
> 
>       "")
>-        claim_lock "block"
>         success
>         release_lock "block"
> 	;;
>@@ -299,25 +309,26 @@
>   remove)
>     case $t in 
>       phy)
>-	exit 0
>+	exit0
> 	;;
> 
>       file)
>-        claim_lock "block"
>         node=$(xenstore_read "$XENBUS_PATH/node")
> 	losetup -d "$node"
>         release_lock "block"
>-	exit 0
>+	exit0
> 	;;
> 
>       "")
>-        exit 0
>+        exit0
> 	;;
>     esac
>     ;;
> 
> esac
> 
>+release_lock "block"
>+
> # If we've reached here, $t is neither phy nor file, so fire a helper script.
> [ -x /etc/xen/scripts/block-"$t" ] && \
>   /etc/xen/scripts/block-"$t" "$command" $node

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Attachments on bug 1100080: 922599 | 922600 | 927142