minios: fix xenbus_rm() calls in frontend drivers

The commit "minios: refactor xenbus state machine" caused "/state" to
be appended to the local value of nodename. Previously the nodename
variable pointed to dev->nodename.

The xenbus_rm() calls were not updated to reflect this change, and
refer to paths that do not exist.

For example, shutdown_blkfront() for vbd 2049 would issue these calls:
    xenbus_rm(XBT_NIL, "device/vbd/2049/state/ring-ref");
    xenbus_rm(XBT_NIL, "device/vbd/2049/state/event-channel");

This patch restores the previous behavior, issuing these calls
instead:
    xenbus_rm(XBT_NIL, "device/vbd/2049/ring-ref");
    xenbus_rm(XBT_NIL, "device/vbd/2049/event-channel");

This causes frontend drivers to not be properly reset when PV-GRUB
exists. Some PV Linux drivers fail to re-initialize frontend devices
if PV-GRUB leaves them in this state.

Signed-off-by: Ben Cressey <bcressey@amazon.com>
Reviewed-by: Matt Wilson <msw@amazon.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
[msw: adjusted commit message to include consequences, split out
 changes into separate patches]
Signed-off-by: Matt Wilson <msw@amazon.com>

diff --git a/blkfront.c b/blkfront.c
index dd5e95f295baaac127638b69a25fd993742ef5b8..ddcf665898df3fa48f36d2905727273214d2d78f 100644 (file)
--- a/blkfront.c
+++ b/blkfront.c
@@ -297,10 +297,10 @@ close:
     if (err) free(err);
     xenbus_unwatch_path_token(XBT_NIL, path, path);
 
-    snprintf(path, sizeof(path), "%s/ring-ref", nodename);
-    xenbus_rm(XBT_NIL, path);
-    snprintf(path, sizeof(path), "%s/event-channel", nodename);
-    xenbus_rm(XBT_NIL, path);
+    snprintf(nodename, sizeof(nodename), "%s/ring-ref", dev->nodename);
+    xenbus_rm(XBT_NIL, nodename);
+    snprintf(nodename, sizeof(nodename), "%s/event-channel", dev->nodename);
+    xenbus_rm(XBT_NIL, nodename);
 
     if (!err)
         free_blkfront(dev);

diff --git a/fbfront.c b/fbfront.c
index 8b4466a5900871b1f87f3026db5f390da2eb335b..3d0b8f5865e14e558de7f587eb33864e554eaea1 100644 (file)
--- a/fbfront.c
+++ b/fbfront.c
@@ -280,12 +280,12 @@ close_kbdfront:
     if (err) free(err);
     xenbus_unwatch_path_token(XBT_NIL, path, path);
 
-    snprintf(path, sizeof(path), "%s/page-ref", nodename);
-    xenbus_rm(XBT_NIL, path);
-    snprintf(path, sizeof(path), "%s/event-channel", nodename);
-    xenbus_rm(XBT_NIL, path);
-    snprintf(path, sizeof(path), "%s/request-abs-pointer", nodename);
-    xenbus_rm(XBT_NIL, path);
+    snprintf(nodename, sizeof(nodename), "%s/page-ref", dev->nodename);
+    xenbus_rm(XBT_NIL, nodename);
+    snprintf(nodename, sizeof(nodename), "%s/event-channel", dev->nodename);
+    xenbus_rm(XBT_NIL, nodename);
+    snprintf(nodename, sizeof(nodename), "%s/request-abs-pointer", dev->nodename);
+    xenbus_rm(XBT_NIL, nodename);
 
     if (!err)
         free_kbdfront(dev);
@@ -671,14 +671,14 @@ close_fbfront:
     if (err) free(err);
     xenbus_unwatch_path_token(XBT_NIL, path, path);
 
-    snprintf(path, sizeof(path), "%s/page-ref", nodename);
-    xenbus_rm(XBT_NIL, path);
-    snprintf(path, sizeof(path), "%s/event-channel", nodename);
-    xenbus_rm(XBT_NIL, path);
-    snprintf(path, sizeof(path), "%s/protocol", nodename);
-    xenbus_rm(XBT_NIL, path);
-    snprintf(path, sizeof(path), "%s/feature-update", nodename);
-    xenbus_rm(XBT_NIL, path);
+    snprintf(nodename, sizeof(nodename), "%s/page-ref", dev->nodename);
+    xenbus_rm(XBT_NIL, nodename);
+    snprintf(nodename, sizeof(nodename), "%s/event-channel", dev->nodename);
+    xenbus_rm(XBT_NIL, nodename);
+    snprintf(nodename, sizeof(nodename), "%s/protocol", dev->nodename);
+    xenbus_rm(XBT_NIL, nodename);
+    snprintf(nodename, sizeof(nodename), "%s/feature-update", dev->nodename);
+    xenbus_rm(XBT_NIL, nodename);
 
     if (!err)
         free_fbfront(dev);

diff --git a/netfront.c b/netfront.c
index dc29f14075a68c488b6291700984d97feedb852b..4e087a56ed86ea5157bbf35d067826ca447d3b55 100644 (file)
--- a/netfront.c
+++ b/netfront.c
@@ -549,14 +549,14 @@ close:
     if (err) free(err);
     xenbus_unwatch_path_token(XBT_NIL, path, path);
 
-    snprintf(path, sizeof(path), "%s/tx-ring-ref", nodename);
-    xenbus_rm(XBT_NIL, path);
-    snprintf(path, sizeof(path), "%s/rx-ring-ref", nodename);
-    xenbus_rm(XBT_NIL, path);
-    snprintf(path, sizeof(path), "%s/event-channel", nodename);
-    xenbus_rm(XBT_NIL, path);
-    snprintf(path, sizeof(path), "%s/request-rx-copy", nodename);
-    xenbus_rm(XBT_NIL, path);
+    snprintf(nodename, sizeof(nodename), "%s/tx-ring-ref", dev->nodename);
+    xenbus_rm(XBT_NIL, nodename);
+    snprintf(nodename, sizeof(nodename), "%s/rx-ring-ref", dev->nodename);
+    xenbus_rm(XBT_NIL, nodename);
+    snprintf(nodename, sizeof(nodename), "%s/event-channel", dev->nodename);
+    xenbus_rm(XBT_NIL, nodename);
+    snprintf(nodename, sizeof(nodename), "%s/request-rx-copy", dev->nodename);
+    xenbus_rm(XBT_NIL, nodename);
 
     if (!err)
         free_netfront(dev);

diff --git a/pcifront.c b/pcifront.c
index df300b5a4ef14349f43e793f596809ba652427cd..cdf9c9b0b1e52925040736bf6110efdc006b61a0 100644 (file)
--- a/pcifront.c
+++ b/pcifront.c
@@ -363,10 +363,10 @@ close_pcifront:
     if (err) free(err);
     xenbus_unwatch_path_token(XBT_NIL, path, path);
 
-    snprintf(path, sizeof(path), "%s/info-ref", nodename);
-    xenbus_rm(XBT_NIL, path);
-    snprintf(path, sizeof(path), "%s/event-channel", nodename);
-    xenbus_rm(XBT_NIL, path);
+    snprintf(nodename, sizeof(nodename), "%s/info-ref", dev->nodename);
+    xenbus_rm(XBT_NIL, nodename);
+    snprintf(nodename, sizeof(nodename), "%s/event-channel", dev->nodename);
+    xenbus_rm(XBT_NIL, nodename);
 
     if (!err)
         free_pcifront(dev);