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039bdad732
Add LV_TEMPORARY flag for LVs with limited existence during command execution. Such LVs are temporary in way that they need to be activated, some action done and then removed immediately. Such LVs are just like any normal LV - the only difference is that they are removed during LVM command execution. This is also the case for LVs representing future pool metadata spare LVs which we need to initialize by using the usual LV before they are declared as pool metadata spare. We can optimize some other parts like udev to do a better job if it knows that the LV is temporary and any processing on it is just useless. This flag is orthogonal to LV_NOSCAN flag introduced recently as LV_NOSCAN flag is primarily used to mark an LV for the scanning to be avoided before the zeroing of the device happens. The LV_TEMPORARY flag makes a difference between a full-fledged LV visible in the system and the LV just used as a temporary overlay for some action that needs to be done on underlying PVs. For example: lvcreate --thinpool POOL --zero n -L 1G vg - first, the usual LV is created to do a clean up for pool metadata spare. The LV is activated, zeroed, deactivated. - between "activated" and "zeroed" stage, the LV_NOSCAN flag is used to avoid any scanning in udev - betwen "zeroed" and "deactivated" stage, we need to avoid the WATCH udev rule, but since the LV is just a usual LV, we can't make a difference. The LV_TEMPORARY internal LV flag helps here. If we create the LV with this flag, the DM_UDEV_DISABLE_DISK_RULES and DM_UDEV_DISABLE_OTHER_RULES flag are set (just like as it is with "invisible" and non-top-level LVs) - udev is directed to skip WATCH rule use. - if the LV_TEMPORARY flag was not used, there would normally be a WATCH event generated once the LV is closed after "zeroed" stage. This will make problems with immediated deactivation that follows. |
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| .. | ||
| lv_alloc.h | ||
| lv_manip.c | ||
| lv.c | ||
| lv.h | ||
| merge.c | ||
| metadata-exported.h | ||
| metadata.c | ||
| metadata.h | ||
| mirror.c | ||
| pv_alloc.h | ||
| pv_manip.c | ||
| pv_map.c | ||
| pv_map.h | ||
| pv.c | ||
| pv.h | ||
| raid_manip.c | ||
| replicator_manip.c | ||
| segtype.c | ||
| segtype.h | ||
| snapshot_manip.c | ||
| thin_manip.c | ||
| vg.c | ||
| vg.h | ||