[PATCH mirror 0/13] Stacking and collapsing mirror (rev. 2)

[PATCH mirror 0/13] Stacking and collapsing mirror (rev. 2)

[Jun'ichi Nomura]

This set of patches allows mirror addition to mirrored LV.

The patchset is an updated version of this one:
[PATCH mirror 0/13] Add/collapse temporary mirror
https://www.redhat.com/archives/lvm-devel/2007-November/msg00040.html

Changes:
  - rebased to the CVS head, which contains most of the latest
    pvmove/lvconvert patchset

[ 1/13] Add 'const' for mirror-related functions
[ 2/13] Misc fixes to the 'lvconvert' generalization
[ 3/13] Enable layer specification in remove_layer_from_lv()
[ 4/13] lv_rename() to walk down the stacked LV
[ 5/13] lv_mirror_count() to cope with stacked mirror
[ 6/13] remove_mirror_images() to cope with stacked mirror
[ 7/13] lv_extend() to cope with stacked mirror
[ 8/13] lvconvert to stack a temporary resync mirror  on addition
[ 9/13] Add collapsing feature for stacked mirror
[10/13] Add '--collapse' option to lvconvert
[11/13] Add 'lv_mirrors' field to reporting functions
[12/13] Remove hardcoded "_mlog" name from deptree construction
[13/13] Allow disk logs for temporary resync mirror

Comments are welcome.


Overview of the patches
--------------------------

Current LVM2 mirror doesn't allow mirror addition to already
mirrored LV.
It's not possible to simply add mirror image to the existing LV
because it will result in full resync even if existing images are
already in sync.

With this patchset, a temporary mirror layer is inserted.

For example, if we have the mirrored LV below:
  testvg-lvol0
   |-testvg-lvol0_mimage_1
   |-testvg-lvol0_mimage_0
   `-testvg-lvol0_mlog0

'lvconvert -m+1' will result in this:
  testvg-lvol0
   |-testvg-lvol0_mimage_2
   |-testvg-lvol0_resync0
   |  |-testvg-lvol0_mimage_1
   |  |-testvg-lvol0_mimage_0
   |  `-testvg-lvol0_mlog0
   `-testvg-lvol0_mlog1

"resync0" is a temporary layer to resync "mimage_2".

'lvs -o mirrors testvg/lvol0' will show "3" as a number of mirror images.

After the resync completes, 'lvconvert --collapse testvg/lvol0' will
change the LV to this form:
  testvg-lvol0
   |-testvg-lvol0_mimage_2
   |-testvg-lvol0_mimage_1
   |-testvg-lvol0_mimage_0
   `-testvg-lvol0_mlog0

Thanks,
-- 
Jun'ichi Nomura, NEC Corporation of America

[PATCH mirror 1/13] Add 'const' for mirror-related functions

[Jun'ichi Nomura]

Some mirror-related functions should use 'const'.
It will save warnings when we use lv_mirror_count() from reporting
function.

Thanks,
-- 
Jun'ichi Nomura, NEC Corporation of America
-------------- next part --------------
A non-text attachment was scrubbed...
Name: const-mirror.patch
Type: text/x-patch
Size: 3316 bytes
Desc: not available
URL: <http://listman.redhat.com/archives/lvm-devel/attachments/20071220/e5c1e5df/attachment.bin>

[PATCH mirror 2/13] Misc fixes to the 'lvconvert' generalization

[Jun'ichi Nomura]

This small patch contains misc fixes to the lvconvert generalization
code that has been just committed to CVS.

  - lv_add_mirror_lvs() should turn off VISIBLE_LV flag of
    each mimage LV.
  - 'struct alloc_handle' declaration in metadata-exported.h
    is not needed as create_mirror_layers() was removed.
  - lv_remove_mirrors() should use lv_mirror_count() instead of
    seg->area_count.

Thanks,
-- 
Jun'ichi Nomura, NEC Corporation of America
-------------- next part --------------
A non-text attachment was scrubbed...
Name: lvm2-lv_add_mirror-fixups.patch
Type: text/x-patch
Size: 2042 bytes
Desc: not available
URL: <http://listman.redhat.com/archives/lvm-devel/attachments/20071220/168c4546/attachment.bin>

[PATCH mirror 3/13] Enable layer specification in remove_layer_from_lv()

[Jun'ichi Nomura]

Added layer_lv argument to remove_layer_from_lv().

remove_layer_from_lv() has implicitly removed the top-most layer.
It won't work if the layer can be stacked.
The caller knows which layer it wants to remove.

find_parent_for_layer() will help find a parent LV for specified layer LV.

Thanks,
-- 
Jun'ichi Nomura, NEC Corporation of America
-------------- next part --------------
A non-text attachment was scrubbed...
Name: lvm2-add-layer-spec-to-remove_layer_from_lv.patch
Type: text/x-patch
Size: 3914 bytes
Desc: not available
URL: <http://listman.redhat.com/archives/lvm-devel/attachments/20071220/371afea4/attachment.bin>

[PATCH mirror 4/13] lv_rename() to walk down the stacked LV

[Jun'ichi Nomura]

_for_each_sub_lv() is used by lv_rename() to rename the
underlying LVs. But it currently handles only 1 layer.
Let it work recursively for more stacked LV.

Thanks,
-- 
Jun'ichi Nomura, NEC Corporation of America
-------------- next part --------------
A non-text attachment was scrubbed...
Name: lvm2-stacked-lv-rename.patch
Type: text/x-patch
Size: 802 bytes
Desc: not available
URL: <http://listman.redhat.com/archives/lvm-devel/attachments/20071220/ae173ca6/attachment.bin>

[PATCH mirror 5/13] lv_mirror_count() to cope with stacked mirror

[Jun'ichi Nomura]

Change lv_mirror_count() to cope with stacked mirror with resync layers.

When adding mirrors to already mirrored LV, LVM2 will stack a temporary
mirror layer for resync.

So the lv_mirror_count() should take into account these things:
  - loop down through the mirror stack
  - exclude the resync LV from the count

Thanks,
-- 
Jun'ichi Nomura, NEC Corporation of America

-------------- next part --------------
A non-text attachment was scrubbed...
Name: lvm2-stacked-mirror-lv_mirror_count.patch
Type: text/x-patch
Size: 2114 bytes
Desc: not available
URL: <http://listman.redhat.com/archives/lvm-devel/attachments/20071220/bf5cee0f/attachment.bin>

[PATCH mirror 6/13] remove_mirror_images() to cope with stacked mirror

[Jun'ichi Nomura]

Change remove_mirror_images()
  - take LV as an argument, instead of LV segment, because segment-lv
    relationship could change after the layer removal
  - to cope with the stacked mirror LV, check the difference between
    lv_mirror_count() and seg->area_count.
    Iterate in this way: remove legs from the top-level mirror, if
    the mirror is turned to linear, collapse one layer and restart
    with remainder.

Thanks,
-- 
Jun'ichi Nomura, NEC Corporation of America

-------------- next part --------------
A non-text attachment was scrubbed...
Name: lvm2-stacked-mirror-remove_mirror_images.patch
Type: text/x-patch
Size: 7968 bytes
Desc: not available
URL: <http://listman.redhat.com/archives/lvm-devel/attachments/20071220/134f412b/attachment.bin>

[PATCH mirror 7/13] lv_extend() to cope with stacked mirror

[Jun'ichi Nomura]

Mirrored LV could be stacked with temporary resync layers.
So lv_extend() should walk down the stack.

Thanks,
-- 
Jun'ichi Nomura, NEC Corporation of America
-------------- next part --------------
A non-text attachment was scrubbed...
Name: lvm2-stacked-mirror-extend.patch
Type: text/x-patch
Size: 2886 bytes
Desc: not available
URL: <http://listman.redhat.com/archives/lvm-devel/attachments/20071220/227e5519/attachment.bin>

[PATCH mirror 8/13] lvconvert to stack a temporary resync mirror on addition

[Jun'ichi Nomura]

Allow lvconvert to add mirror by inserting a "_resync<n>" layer
and add mirrors to it.

FIXME: Limited to corelog. It'll be fixed with later patches.

Thanks,
-- 
Jun'ichi Nomura, NEC Corporation of America
-------------- next part --------------
A non-text attachment was scrubbed...
Name: lvm2-stacked-mirror-add-mirror.patch
Type: text/x-patch
Size: 1744 bytes
Desc: not available
URL: <http://listman.redhat.com/archives/lvm-devel/attachments/20071220/c0cf5df9/attachment.bin>

[PATCH mirror 9/13] Add collapsing feature for stacked mirror

[Jun'ichi Nomura]

This is the main patch of this patchset.

Add collapsing feature to the stacked mirror.
dmeventd should be changed to call it when it detects the
completion of resync.

Thanks,
-- 
Jun'ichi Nomura, NEC Corporation of America
-------------- next part --------------
A non-text attachment was scrubbed...
Name: lvm2-stacked-mirror-collapse-layers.patch
Type: text/x-patch
Size: 5654 bytes
Desc: not available
URL: <http://listman.redhat.com/archives/lvm-devel/attachments/20071220/2a0a0ecb/attachment.bin>

[PATCH mirror 10/13] Add '--collapse' option to lvconvert

[Jun'ichi Nomura]

This patch adds '--collapse' option to lvconvert command.

Thanks,
-- 
Jun'ichi Nomura, NEC Corporation of America
-------------- next part --------------
A non-text attachment was scrubbed...
Name: lvm2-stacked-mirror-lvconvert.patch
Type: text/x-patch
Size: 3384 bytes
Desc: not available
URL: <http://listman.redhat.com/archives/lvm-devel/attachments/20071220/1bd24207/attachment.bin>

[PATCH mirror 11/13] Add 'lv_mirrors' field to reporting functions

[Jun'ichi Nomura]

This patch adds 'lv_mirrors' field to reporting commands.
It is the number of mirrors for the LV.

Thanks,
-- 
Jun'ichi Nomura, NEC Corporation of America
-------------- next part --------------
A non-text attachment was scrubbed...
Name: lvm2-stacked-mirror-report.patch
Type: text/x-patch
Size: 2769 bytes
Desc: not available
URL: <http://listman.redhat.com/archives/lvm-devel/attachments/20071220/564297d0/attachment.bin>

[PATCH mirror 12/13] Remove hardcoded "_mlog" name from deptree construction

[Jun'ichi Nomura]

This patch removes "_mlog" hardcoding in deptree construction code
and use seg->log_lv instead.

Thanks,
-- 
Jun'ichi Nomura, NEC Corporation of America
-------------- next part --------------
A non-text attachment was scrubbed...
Name: lvm2-deptree-generalize-mlog.patch
Type: text/x-patch
Size: 974 bytes
Desc: not available
URL: <http://listman.redhat.com/archives/lvm-devel/attachments/20071220/f8277303/attachment.bin>

[PATCH mirror 13/13] Allow disk logs for temporary resync mirror

[Jun'ichi Nomura]

With the previous patch ("12/13"), we can use multiple disk logs
in the LV.
So unlock the use of disk log for added mirror.

Thanks,
-- 
Jun'ichi Nomura, NEC Corporation of America
-------------- next part --------------
A non-text attachment was scrubbed...
Name: lvm2-stacked-mirror-multi-mlogs.patch
Type: text/x-patch
Size: 1652 bytes
Desc: not available
URL: <http://listman.redhat.com/archives/lvm-devel/attachments/20071220/d9d6c7a6/attachment.bin>