Change message severity to log_very_verbose for missing dev info in udev db.

Libudev does not provide transactions when querying udev database - once we
get the list of block devices (devices/obtain_device_list_from_udev=1) and
we iterate over the list to get more detailed information about device node
and symlink names used etc., the device could be removed just in between we
get the list and put a query for more info. In this case, libudev returns
NULL value as the device does not exist anymore.

Recently, we've added a warning message to reveal such situations. However,
this could be misleading if the device is not related to the LVM action
we're just processing - the non-related block device could be removed in
parallel and this is not an error but a possible and normal operation.

(N.B. This "missing info" should not happen when devices are related to
the LVM action we're just processing since all such processing should be
synchronized with udev and the udev db must always be in consistent state
after the sync point. But we can't filter this situation out from others,
non-related devices, so we have to lower the message verbosity here for a
general solution.)

diff --git a/WHATS_NEW b/WHATS_NEW
index a0f437abfb4665ffb228b3eee6055fd617bbca8b..e8af5431728a14b3489dd8411520c3f245872fdd 100644 (file)
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,5 +1,6 @@
 Version 2.02.96 - 
 ================================
+  Change message severity to log_very_verbose for missing dev info in udev db.
   Fix problems when specifying PVs during RAID down-converts.
   Fix ability to handle failures in mirrored log (regression intro 2.02.89).
   Fix unlocking volume group in vgreduce in error path.

diff --git a/lib/device/dev-cache.c b/lib/device/dev-cache.c
index 29a619c7d5fcf8564a660892c2c864c6fae2ee3a..c92e11e9e8ce82a274b78583b867a3e762657110 100644 (file)
--- a/lib/device/dev-cache.c
+++ b/lib/device/dev-cache.c
@@ -497,7 +497,7 @@ static int _insert_udev_dir(struct udev *udev, const char *dir)
 {
        struct udev_enumerate *udev_enum = NULL;
        struct udev_list_entry *device_entry, *symlink_entry;
-       const char *node_name, *symlink_name;
+       const char *entry_name, *node_name, *symlink_name;
        struct udev_device *device;
        int r = 1;
 
@@ -508,20 +508,34 @@ static int _insert_udev_dir(struct udev *udev, const char *dir)
            udev_enumerate_scan_devices(udev_enum))
                goto bad;
 
+       /*
+        * Report any missing information as "log_very_verbose" only, do not
+        * report it as a "warning" or "error" - the record could be removed
+        * by the time we ask for more info (node name, symlink name...).
+        * Whatever removes *any* block device in the system (even unrelated
+        * to our operation), we would have a warning/error on output then.
+        * That could be misleading. If there's really any problem with missing
+        * information from udev db, we can still have a look at the verbose log.
+        */
        udev_list_entry_foreach(device_entry, udev_enumerate_get_list_entry(udev_enum)) {
-               if (!(device = udev_device_new_from_syspath(udev, udev_list_entry_get_name(device_entry)))) {
-                       log_warn("WARNING: udev failed to return a device entry.");
+               entry_name = udev_list_entry_get_name(device_entry);
+
+               if (!(device = udev_device_new_from_syspath(udev, entry_name))) {
+                       log_very_verbose("udev failed to return a device for entry %s.",
+                                        entry_name);
                        continue;
                }
 
                if (!(node_name = udev_device_get_devnode(device)))
-                       log_warn("WARNING: udev failed to return a device node.");
+                       log_very_verbose("udev failed to return a device node for entry %s.",
+                                        entry_name);
                else
                        r &= _insert(node_name, 0, 0);
 
                udev_list_entry_foreach(symlink_entry, udev_device_get_devlinks_list_entry(device)) {
                        if (!(symlink_name = udev_list_entry_get_name(symlink_entry)))
-                               log_warn("WARNING: udev failed to return a symlink name.");
+                               log_very_verbose("udev failed to return a symlink name for entry %s.",
+                                                entry_name);
                        else
                                r &= _insert(symlink_name, 0, 0);
                }