Add support for new IMPORT{db} udev rule.

This rule appeared in udev v152 and it helps us to support spurious events
where we didn't have any flags set (events originated in udevadm trigger
or the watch rule). These flags are important to direct the rule application.
Now, with the help of this rule, we can regenerate old udev db content.
To implement this correctly, we need to flag all proper DM udev events with
DM_UDEV_PRIMARY_SOURCE_FLAG. That happens automatically for all ioctls
generating events originated in libdevmapper.

diff --git a/WHATS_NEW_DM b/WHATS_NEW_DM
index d899bd739793c2c54c1f28de4048e65ea15b0c0e..cfc3257e80ac3c6f029588e37f93a3b7bb75d673 100644 (file)
--- a/WHATS_NEW_DM
+++ b/WHATS_NEW_DM
@@ -1,5 +1,7 @@
 Version 1.02.47 -
 =================================
+  Add support for new IMPORT{db} udev rule.
+  Add DM_UDEV_PRIMARY_SOURCE_FLAG udev flag to recognize proper DM events.
   Also include udev libs in libdevmapper.pc when udev_sync is enabled.
   Cache bitset locations to speed up _calc_states.
   Add a regex optimisation pass for shared character prefixes.

diff --git a/libdm/ioctl/libdm-iface.c b/libdm/ioctl/libdm-iface.c
index c37ccbb4cf4ef5165afb1150de6f54ac7f14355f..a34801213b138b9f46cf959ce2240448bb18762c 100644 (file)
--- a/libdm/ioctl/libdm-iface.c
+++ b/libdm/ioctl/libdm-iface.c
@@ -1736,31 +1736,44 @@ static struct dm_ioctl *_do_dm_ioctl(struct dm_task *dmt, unsigned command,
                            dmt->type == DM_DEVICE_REMOVE ||
                            dmt->type == DM_DEVICE_RENAME;
 
-       /*
-        * Prevent udev vs. libdevmapper race when processing nodes and
-        * symlinks. This can happen when the udev rules are installed and
-        * udev synchronisation code is enabled in libdevmapper but the
-        * software using libdevmapper does not make use of it (by not calling
-        * dm_task_set_cookie before). We need to instruct the udev rules not
-        * to be applied at all in this situation so we can gracefully fallback
-        * to libdevmapper's node and symlink creation code.
-        */
-       if (dm_udev_get_sync_support() && !dmt->cookie_set && ioctl_with_uevent) {
-               log_debug("Cookie value is not set while trying to call "
-                         "DM_DEVICE_RESUME, DM_DEVICE_REMOVE or DM_DEVICE_RENAME "
-                         "ioctl. Please, consider using libdevmapper's udev "
-                         "synchronisation interface or disable it explicitly "
-                         "by calling dm_udev_set_sync_support(0).");
-               log_debug("Switching off device-mapper and all subsystem related "
-                         "udev rules. Falling back to libdevmapper node creation.");
+       if (ioctl_with_uevent && dm_cookie_supported()) {
                /*
-                * Disable general dm and subsystem rules but keep dm disk rules
-                * if not flagged out explicitly before. We need /dev/disk content
-                * for the software that expects it.
-               */
-               dmi->event_nr |= (DM_UDEV_DISABLE_DM_RULES_FLAG |
-                                 DM_UDEV_DISABLE_SUBSYSTEM_RULES_FLAG) <<
+                * Always mark events coming from libdevmapper as
+                * "primary sourced". This is needed to distinguish
+                * any spurious events so we can act appropriately.
+                * This needs to be applied even when udev_sync is
+                * not used because udev flags could be used alone.
+                */
+               dmi->event_nr |= DM_UDEV_PRIMARY_SOURCE_FLAG <<
                                 DM_UDEV_FLAGS_SHIFT;
+
+               /*
+                * Prevent udev vs. libdevmapper race when processing nodes
+                * and symlinks. This can happen when the udev rules are
+                * installed and udev synchronisation code is enabled in
+                * libdevmapper but the software using libdevmapper does not
+                * make use of it (by not calling dm_task_set_cookie before).
+                * We need to instruct the udev rules not to be applied at
+                * all in this situation so we can gracefully fallback to
+                * libdevmapper's node and symlink creation code.
+                */
+               if (!dmt->cookie_set && dm_udev_get_sync_support()) {
+                       log_debug("Cookie value is not set while trying to call "
+                                 "DM_DEVICE_RESUME, DM_DEVICE_REMOVE or DM_DEVICE_RENAME "
+                                 "ioctl. Please, consider using libdevmapper's udev "
+                                 "synchronisation interface or disable it explicitly "
+                                 "by calling dm_udev_set_sync_support(0).");
+                       log_debug("Switching off device-mapper and all subsystem related "
+                                 "udev rules. Falling back to libdevmapper node creation.");
+                       /*
+                        * Disable general dm and subsystem rules but keep
+                        * dm disk rules if not flagged out explicitly before.
+                        * We need /dev/disk content for the software that expects it.
+                       */
+                       dmi->event_nr |= (DM_UDEV_DISABLE_DM_RULES_FLAG |
+                                         DM_UDEV_DISABLE_SUBSYSTEM_RULES_FLAG) <<
+                                        DM_UDEV_FLAGS_SHIFT;
+               }
        }
 
        log_debug("dm %s %s %s%s%s %s%.0d%s%.0d%s"

diff --git a/libdm/libdevmapper.h b/libdm/libdevmapper.h
index 0ee23fbb577bdbe9d9965bc3f986aac65239104f..0900a3beb3d70a881e9d42f926e04f2999bb9513 100644 (file)
--- a/libdm/libdevmapper.h
+++ b/libdm/libdevmapper.h
@@ -1094,6 +1094,16 @@ void dm_report_field_set_value(struct dm_report_field *field, const void *value,
  * udev does something improperly.
  */
 #define DM_UDEV_DISABLE_LIBRARY_FALLBACK 0x0020
+/*
+ * DM_UDEV_PRIMARY_SOURCE_FLAG is automatically appended by
+ * libdevmapper for all ioctls generating udev uevents. Once used in
+ * udev rules, we know if this is a real "primary sourced" event or not.
+ * We need to distinguish real events originated in libdevmapper from
+ * any spurious events to gather all missing information (e.g. events
+ * generated as a result of "udevadm trigger" command or as a result
+ * of the "watch" udev rule).
+ */
+#define DM_UDEV_PRIMARY_SOURCE_FLAG 0x0040
 
 int dm_cookie_supported(void);
 

diff --git a/tools/dmsetup.c b/tools/dmsetup.c
index 0f02f3c0c5bd46f6904a3effaf536b51f3d0b171..85dd7fb14f5323687aa669e30fbf81c839d9e1e2 100644 (file)
--- a/tools/dmsetup.c
+++ b/tools/dmsetup.c
@@ -842,7 +842,8 @@ static int _udevflags(int args, char **argv, void *data __attribute((unused)))
                                              "DISABLE_OTHER_RULES",
                                              "LOW_PRIORITY",
                                              "DISABLE_LIBRARY_FALLBACK",
-                                              0, 0};
+                                             "PRIMARY_SOURCE",
+                                              0};
 
        if (!(cookie = _get_cookie_value(argv[1])))
                return 0;

diff --git a/udev/10-dm.rules.in b/udev/10-dm.rules.in
index 7cffc0bfba3764a02942e0fc0e6f5910f8af1c69..0db88093aa9b22d321ecf749148b1b95a0b838f6 100644 (file)
--- a/udev/10-dm.rules.in
+++ b/udev/10-dm.rules.in
@@ -44,6 +44,28 @@ ENV{DM_COOKIE}=="?*", IMPORT{program}="$env{DM_SBIN_PATH}/dmsetup udevflags $env
 
 ACTION!="add|change", GOTO="dm_end"
 
+# There is no cookie set nor any flags encoded in events not originating
+# in libdevmapper so we need to detect this and try to behave correctly.
+# For such spurious events, regenerate all flags from current udev database content
+# (this information would normally be inaccessible for spurious ADD and CHANGE events).
+ENV{DM_UDEV_PRIMARY_SOURCE_FLAG}=="1", GOTO="dm_flags_done"
+IMPORT{db}="DM_UDEV_DISABLE_DM_RULES_FLAG"
+IMPORT{db}="DM_UDEV_DISABLE_SUBSYSTEM_RULES_FLAG"
+IMPORT{db}="DM_UDEV_DISABLE_DISK_RULES_FLAG"
+IMPORT{db}="DM_UDEV_DISABLE_OTHER_RULES_FLAG"
+IMPORT{db}="DM_UDEV_LOW_PRIORITY_FLAG"
+IMPORT{db}="DM_UDEV_DISABLE_LIBRARY_FALLBACK_FLAG"
+IMPORT{db}="DM_UDEV_FLAG7"
+IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG0"
+IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG1"
+IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG2"
+IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG3"
+IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG4"
+IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG5"
+IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG6"
+IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG7"
+LABEL="dm_flags_done"
+
 # Normally, we operate on "change" events only. But when
 # coldplugging, there's an "add" event present. We have to
 # recognize this and do our actions in this particular