The snapshot-merge target allows a snapshot to be merged back into the snapshot's origin device. One expected use of snapshot merging is the rollback of a root filesystem after system upgrades (e.g.: yum update). snapshot-merge enables "system rollback" support for any filesystem that is using the associated DM/LVM devices. * "[PATCH v4 05/13] dm snapshot: add snapshot-merge target" adds further documentation to: Documentation/device-mapper/snapshot.txt * All patch headers have been revised/audited for added clarity. * Both the latest handover (v10) and origin-write patch have been included in this series. * Aside from snapshot-merge specific testing these patches have survived 75+ iterations of lvm2's testsuite without any failures. The test kernel was 2.6.32-rc8 and lvm2 was 2.0.55 (with udev_sync enabled and dmeventd disabled). The snapshot-merge quilt tree is maintained here: http://people.redhat.com/msnitzer/patches/snapshot-merge/kernel/2.6.33/ For LVM2 support please see: http://people.redhat.com/msnitzer/patches/snapshot-merge/lvm2/LVM2-2.02.55/ Mike Snitzer (3): dm snapshot: allow live exception store handover between tables dm exception store: snapshot-merge usage accounting dm snapshot: merge a linear region of chunks using one large IO Mikulas Patocka (10): dm snapshot: rework writing to snapshot origin dm exception store: add snapshot-merge specific methods dm snapshot: add snapshot-merge target dm snapshot: merge target should not allocate new exceptions dm snapshot: do not allow more than one merging snapshot. dm snapshot: the merge procedure dm snapshot: queue writes to an area that is actively being merged dm snapshot: do not merge a chunk until active writes to it finish dm snapshot: make exceptions in other snapshots when merging dm snapshot: redirect accesses to origin if merging snap invalidated Documentation/device-mapper/snapshot.txt | 52 ++- drivers/md/dm-exception-store.h | 27 + drivers/md/dm-snap-persistent.c | 91 ++++- drivers/md/dm-snap.c | 827 ++++++++++++++++++++++++------ 4 files changed, 839 insertions(+), 158 deletions(-) -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
