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8d1d83504d
This patch fixes the way the special devices are handled
(special in this context means that they're not usable
after the usual ADD event like other generic devices):
- DM and MD devices are pvscanned only when they are just set up.
This is the first CHANGE event that makes the device usable
(the DM_UDEV_PRIMARY_SOURCE_FLAG is set for DM and the
md/array_state sysfs attribute is present for MD).
Whether the device is activated is remembered via
DM_ACTIVATED (for DM) and LVM_MD_PV_ACTIVATED (for MD)
udev environment variable. This is then used to decide
whether we should fire the pvscan on ADD event to
support coldplugging. For any (artificial) ADD event
generated during coldplug, the device must be already
set up properly to fire the pvscan on it.
- Similar for loop devices. For loop devices, only CHANGE
events are relevant (so there's a CHANGE after the loop
device is set up as well as detached). Whether the loop
has just been activated is detected via loop/backing_file
sysfs attribute presence. The activation state is remembered
via LVM_LOOP_PV_ACTIVATED udev environment variable.
- Do not pvscan multipath device components (underlying paths).
- Do not pvscan RAID device components.
- Also, set LVM_SCANNED="1" udev environment variable for
debug purposes (it's visible in the lvmdump -u that takes
the current udev database). This variable is set once
the pvscan is triggered.
The table below summarises when the pvscan is triggered
(marked with X, X* means fire only if the special dev is properly set up):
| real ADD | real CHANGE | artificial ADD | artificial CHANGE | remove
=============================================================================
DM | | X | X* | | X
MD | | X | X* | |
loop | | X | X* | |
other | X | | X | | X
This tree contains the LVM2 and device-mapper tools and libraries. For more information about LVM2 read the changelog in the WHATS_NEW file. Installation instructions are in INSTALL. There is no warranty - see COPYING and COPYING.LIB. Tarballs are available from: ftp://sources.redhat.com/pub/lvm2/ The source code is stored in git: http://git.fedorahosted.org/git/lvm2.git git clone git://git.fedorahosted.org/git/lvm2.git Mailing list for general discussion related to LVM2: linux-lvm@redhat.com Subscribe from https://www.redhat.com/mailman/listinfo/linux-lvm Mailing lists for LVM2 development, patches and commits: lvm-devel@redhat.com Subscribe from https://www.redhat.com/mailman/listinfo/linux-lvm lvm2-commits@lists.fedorahosted.org (Read-only archive of commits) Subscribe from https://fedorahosted.org/mailman/listinfo/lvm2-commits Mailing list for device-mapper development, including kernel patches and multipath-tools: dm-devel@redhat.com Subscribe from https://www.redhat.com/mailman/listinfo/dm-devel The source code repository used until 7th June 2012 is accessible here: http://sources.redhat.com/cgi-bin/cvsweb.cgi/LVM2/?cvsroot=lvm2.