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Commit Graph

1158 Commits

Author SHA1 Message Date
Zdenek Kabelac
42beb34826 Set missing header define 2012-01-25 22:37:48 +00:00
Zdenek Kabelac
9b1fe5a062 Thin clear stacked message for thin pool
Before removing thin pool LV always make sure, stacked message
for previous run are cleared - but allow to remove any
device that should have been created
(i.e. creation of snapshot failed - so the message for snapshot creation
may be replaced with delete message within unfinished transaction).

Also commit messages after lv remove - so free space is released in pool.
2012-01-25 11:27:42 +00:00
Zdenek Kabelac
89764fd494 Thin skip activation when there are no thin message
If the list with thin messages is empty, do not touch thin pool device.
2012-01-25 09:17:15 +00:00
Zdenek Kabelac
c771a70882 Thin correct activation order
When the message is passed only in resume path the order needs
to be corrected.
2012-01-25 09:15:44 +00:00
Zdenek Kabelac
3dadb176ce Thin use suspend/resume_lv_origin
Use origin_only support for thin volume when thin snapshot is created.
2012-01-25 09:14:25 +00:00
Zdenek Kabelac
2258242f6c Thin use origin_only for thin pools as well
Extend the usage of origin_only flag to allow resume of thin pool LV
(when it's active) to pass only the messages.

origin_only flag will skip detection of already resumed tree for thin_pool,
so we do not need to suspend the tree and we just send messages.
2012-01-25 09:13:10 +00:00
Zdenek Kabelac
1dede50c85 Thin check for lv_thin_pool_percent error status
Check has been missing.
2012-01-25 09:02:35 +00:00
Zdenek Kabelac
0926438aad Thin prevent removal of its data and metadata LVs
LVs cannot be removed while there are linked to thin pool.
(Gives better error message, than validation).
2012-01-25 08:57:25 +00:00
Zdenek Kabelac
d55aa53816 Thin fix transaction_id incrementation and code refactoring
Add pool_has_message and use it in attach_pool_message.
Also update header to make more obvious which segment type is
expected as parameter.
Rename  'read_only' to  'no_update' (no auto update transaction_id)
to better fit how it's used.
Fix problem when there was only one stacked message replaced with delete
message that caused unwanted transaction_id increase.
2012-01-25 08:55:19 +00:00
Zdenek Kabelac
c217690f4c Thin dependency scan support
Go through pool_lv and metadata_lv LVs when doing recursive scan.
2012-01-25 08:50:10 +00:00
Alasdair Kergon
3f61871f38 Caller is still entitled to reference an LV that's unlinked, so don't
tamper with struct contents.
2012-01-24 14:53:59 +00:00
Jonathan Earl Brassow
6cf3274732 Use suspend|resume_origin_only when up-converting RAID LVs, as mirrors do.
Failure to do so results in "Performing unsafe table load while X device(s) are
known to be suspended" errors.  While fixing the problem in this way works and
is consistent with the way the mirror segment type does it, it would be nice
to find a solution that uses the generic suspend/resume calls.

Also included in this check-in are additions to the test suite that perform
conversions on RAID LVs under a snapshot.  These tests are disabled for the
time being due to a kernel bug that is yet to be tracked down.
2012-01-24 14:33:38 +00:00
Milan Broz
095d95d0a8 Properly show LV removal message.
(Fix regression in commit 6e181ba96d)
2012-01-24 14:15:52 +00:00
Alasdair Kergon
46c67b5279 Use chunk_size consistently for thin_pool within LVM. 2012-01-24 00:55:03 +00:00
Alasdair Kergon
5c9eae9647 Reorder fns in libdm-deptree.
Tweak dm_config interface and remove FIXMEs.
2012-01-23 17:46:31 +00:00
Mike Snitzer
fc0f2d5031 Prompt if request is made to remove a snapshot whose "Merge failed". 2012-01-20 22:04:16 +00:00
Mike Snitzer
27e21a4adc Allow removal of an invalid snapshot that was to be merged on next activation.
Don't allow a user to merge an invalid snapshot.
2012-01-20 22:03:48 +00:00
Mike Snitzer
d658922f36 Use m and M lv_attr to indicate that a snapshot merge failed in lvs.
snapshot (m)erge failed, suspended snapshot (M)erge failed
2012-01-20 22:03:03 +00:00
Zdenek Kabelac
6515946e4d Thin cleanup
Reorder condition so the code is better readable (and shorter).
2012-01-20 10:56:30 +00:00
Zdenek Kabelac
f881095a69 Drop hack in segtype reporting
Since striped name function knows when to report 'linear' instead of
'stripe' type name - drop it from this place.

This fixes problem when reporting segtype e.g. for thin-pool which
is also using area_count=1 to store thin data device reference.

It also returns properly strduped memory instead of badly casted const char*.
2012-01-20 10:55:28 +00:00
Zdenek Kabelac
f82bddb76c Thin disable snapshot creation when pool is over the threshold.
Since snapshot needs to suspend origin - it might lead to pool userspace
deadlock (as the pool will wait for new space in case it would be overfilled,
but dmeventd would not be able to resize it, as the lvcreate operation would
have kept the VG lock.)
To minimize the risk of such scenario - we prevent to create new snapshot
in case we are over the threshold - but beware, there is still small timewindow,
so keep threshold at some reasonable level!
2012-01-19 15:39:41 +00:00
Zdenek Kabelac
e58b5dd8e8 Thin add new display field for lvs
New field Data% is able to display info about
thin_pool, thin, snapshot and has generic meaning here.

Simple Time/Host field are here to display host and time creation.
2012-01-19 15:34:32 +00:00
Zdenek Kabelac
53d7985fa1 Add support to keep info about creation time and host for each LV
Basic support to keep info when the LV was created.
Host and time is stored into LV mda section.

FIXME: Current version doesn't support configurable string via lvm.conf
and used fixed version strftime "%Y-%m-%d %T %z".
2012-01-19 15:31:45 +00:00
Zdenek Kabelac
d8106dfee2 Thin rename seg var pool_metadata_lv to metadata_lv
Better fits the code.
2012-01-19 15:23:50 +00:00
Alasdair Kergon
8f95d94b4f Show read-only activation in display tools. 2012-01-12 16:58:43 +00:00
Zdenek Kabelac
f582793f1b Thin rename internal thin pool segment
Use matching name as kernel target - useful when function like
_percent is using this for validation.
2011-12-21 12:54:19 +00:00
Alasdair Kergon
66e5b7f53c Reinstate support for format1 snapshots, but issue deprecated warning.
I anticipate removing support for snapshots with lvm1-formatted metadata in a
future release.
2011-12-20 00:02:18 +00:00
Alasdair Kergon
289ed221d0 update FIXMEs 2011-12-10 00:47:23 +00:00
Jonathan Earl Brassow
9711057499 Don't allow two images to be split and tracked from a RAID LV at one time
Also, don't allow a splitmirror operation on a RAID LV that is already tracking
a split, unless the operation is to stop the tracking and complete the split.
Example:
~> lvconvert --splitmirrors 1 --trackchanges vg/lv /dev/sdc1
# Now tracking changes - image can be merged back or split-off for good
~> lvconvert --splitmirrors 1 -n new_name vg/lv /dev/sdc1
# ^ Completes split ^

If a split is performed on a RAID that is tracking an already split image and
PVs are provided, we must ensure that
 1) the already split LV is represented in the PVs
 2) we are careful to split only the tracked image
2011-12-01 00:21:04 +00:00
Jonathan Earl Brassow
a927e401f1 Do not allow users to change the name of RAID sub-LVs or the name of the
RAID LV if it is tracking changes for a split image.
2011-12-01 00:09:34 +00:00
Jonathan Earl Brassow
2ba1e8fccc The LV_REBUILD flag is not internal - bad comments in metadata-exported.h updated 2011-11-30 02:20:13 +00:00
Jonathan Earl Brassow
0c506d9a40 Support the ability to replace specific devices in a RAID array.
RAID is not like traditional LVM mirroring.  LVM mirroring required failed
devices to be removed or the logical volume would simply hang.  RAID arrays can
keep on running with failed devices.  In fact, for RAID types other than RAID1,
removing a device would mean substituting an error target or converting to a
lower level RAID (e.g. RAID6 -> RAID5, or RAID4/5 to RAID0).  Therefore, rather
than removing a failed device unconditionally and potentially allocating a
replacement, RAID allows the user to "replace" a device with a new one.  This
approach is a 1-step solution vs the current 2-step solution.

example> lvconvert --replace <dev_to_remove> vg/lv [possible_replacement_PVs]

'--replace' can be specified more than once.

example> lvconvert --replace /dev/sdb1 --replace /dev/sdc1 vg/lv
2011-11-30 02:02:10 +00:00
Zdenek Kabelac
900f5f8187 Replace dynamic buffer allocations for PATH_MAX
Use static buffer instead of stack allocated buffer.
This reduces stack size usage of lvm tool and the
change is very simple.

Since the whole library is not thread safe - it should not
add any new problems - and if there will be some conversion
it's easy to convert this to use some preallocated buffer.
2011-11-18 19:31:09 +00:00
Zdenek Kabelac
8deeeb07ea Unlock memory for vg_write
For write we do not need to hold memory locked.
This relaxes many conditions and avoid problems when allocating
a lot of memory for writting metadata buffers.
(In case of huge MDA size this would lead to mismatch between
locked and unlocked memory region size).

Add also internal check we are not writing in critical section.
2011-11-18 19:28:00 +00:00
Zdenek Kabelac
37f274ced9 Query before removing inactive snapshots
Removal of an inactive origin removes also all related snapshots.

When we now support 'old' external snapshots with thin volumes,
removal of pool will not only drop all thin volumes, but as
a consequence also all snapshots - which might be seen a bit
unexpected for the user - so add a query to confirm such action.

lvremove -f will skip the prompt.
2011-11-18 19:25:20 +00:00
Zdenek Kabelac
91e4512619 Adjusted mirror region size only for mirrors and raids
Update region_size only for mirror and raid targets.
This fixes warning messages when vg is using small
extent size like 1KiB and no mirror/raid is created,
but the user still got the message:

$> vgcreate -s 1K vg  <pvs>
$> lvcreate -L10K vg
Using reduced mirror region size of 4 sectors
2011-11-15 17:32:12 +00:00
Zdenek Kabelac
5f129d15b1 Thin update prompt message
Enhance message with info about how many thin volumes are going to
be removed with thin pool removal.
2011-11-15 17:29:52 +00:00
Zdenek Kabelac
8542953f74 Reorder AND test condition
Take the easiest condition for checking first since they must
apply all together, check local conditions first before doing
more expensive tests.
2011-11-15 17:27:41 +00:00
Zdenek Kabelac
25de8ca372 Thin supports only thin volumes as snapshot origins
It's currently of the scope to properly solve the snapshoting
of internal thin devs so prevent non-toplevel snapshots here.
2011-11-15 17:23:51 +00:00
Zdenek Kabelac
dd0c58c69b Add missing stack reporting
also remove unneeded {}
2011-11-12 22:53:23 +00:00
Zdenek Kabelac
3af072cc63 Thin use items iterator and stack reporting 2011-11-12 22:52:18 +00:00
Zdenek Kabelac
651ef6be82 Missing stack printing 2011-11-12 22:51:20 +00:00
Zdenek Kabelac
6e89eb9a52 Small comment and indent updates 2011-11-10 12:43:05 +00:00
Zdenek Kabelac
f201498f99 Thin test min thin_pool size for at least 1 chunk 2011-11-10 12:42:36 +00:00
Zdenek Kabelac
39fc633957 Thin align volume size on chunk boundary size
If the extent_size is smaller then the chunk_size we may try
to find better aligment (wasting less space).

i.e. using  4KB extent_size and  64KB chunk size will
lead to creation of 64KB aligned thin volume.
2011-11-10 12:42:15 +00:00
Zdenek Kabelac
74e53e8bc0 Thin disable pool create without activation 2011-11-10 12:39:01 +00:00
Alasdair Kergon
3da4ed712e Must not override alloc policy specified by user. 2011-11-07 13:54:54 +00:00
Zdenek Kabelac
65e88e6b3c Thin add error message for double delete
Add few more internal error messages.
2011-11-07 11:04:45 +00:00
Zdenek Kabelac
97d7e5aedb Thin supports snapshots
Full support for thin snapshots.
Create and remove is supported.

TODO: lvconvert support is not yes available.
2011-11-07 11:03:47 +00:00
Zdenek Kabelac
11721819a7 Thin reindent code
Drop indention level
Add extra internal error.
2011-11-07 10:59:07 +00:00
Zdenek Kabelac
87371d48cc Thin revert code for exclusive pool activation
There are no limits on thin-pool activation now.
Revert code that is no longer needed.
2011-11-07 10:58:13 +00:00
Zdenek Kabelac
4079a8f298 Avoid lvextend to overflow
Add extra check to extent_count overflow.
Use internal define MAX_EXTENT_COUNT instead UINT32_MAX.
2011-11-04 22:49:53 +00:00
Zdenek Kabelac
83baa0b778 Thin pool allocation simplified
Support allocation of metadata from the same PV, if the VG
is build only from one PV.

As thinp is not mirror - we do not require 2 PVs
for basic thin usage as user is losing only perfomance.
2011-11-04 22:45:52 +00:00
Zdenek Kabelac
bd15208cd7 Thin add thin_pool_metadata_require_separate_pvs
Allow to set different policy for pool from mirrors.
2011-11-04 22:44:21 +00:00
Zdenek Kabelac
b8cac455bd Thin supports poolmetadatasize setting
Add option to set pool metadatasize.
For passing size parameter reuse region_size.
2011-11-04 22:43:10 +00:00
Alasdair Kergon
13dc67cda7 Add missing lvrename mirrored log recursion in for_each_sub_lv. 2011-11-04 01:31:23 +00:00
Zdenek Kabelac
1cae10a36c Thin keep pool device in the same state
Leave the optimalisation to be done differently and preserve
availability state of the pool device.
2011-11-03 15:58:20 +00:00
Zdenek Kabelac
9aa24bd034 Thin no device is created - so nothing to revert here 2011-11-03 15:46:51 +00:00
Zdenek Kabelac
466a8ebf9d Thin removing unused detach_pool_messages 2011-11-03 14:57:04 +00:00
Zdenek Kabelac
92384bfd0b Thin using update_pool_lv
Replace detach_pool_messages with update_pool_lv.
Move creation code from to 'if' condition into 1.
Ensure creation has finished all previous message operations.
2011-11-03 14:56:20 +00:00
Zdenek Kabelac
73b7bf961b Thin genering update_pool_lv function
Function to trigger pool message passing via resume,
or resize of the pool itself independently on other thins.
2011-11-03 14:53:58 +00:00
Zdenek Kabelac
dc964ab0d3 Thin uses _tdata instead of _tpool for data LV
Switch to different suffix and keep -tpool reserved for overlay device name.
2011-11-03 14:38:36 +00:00
Zdenek Kabelac
1f5c98270d Thin code cleanup
Use iterate_items for list processing.
2011-11-03 14:36:40 +00:00
Zdenek Kabelac
25de9addb6 Thin fix compile warns
Test for dm_snprintf < 0.
Add header for moved backup.
2011-10-30 22:52:08 +00:00
Zdenek Kabelac
7654abc26f Thin creation without activation
All thins are created with the next activation and VG is updated
without messages. Only some basic commands works.
(i.e. lvcreate -an  -V10 -T mvg/pool)
There can be some combination to confuse this system.

This functionality for snapshots is going to be interesting.
2011-10-30 22:07:38 +00:00
Zdenek Kabelac
f0df05e1dd Cleanup unsuccessfully created thin LV
If something fails during creation of thin LV remove such LV
and deactivate in case it's been already tried to activate
(i.e. thin kernel driver fails for some reason.)
2011-10-30 22:02:18 +00:00
Zdenek Kabelac
96279ac1c0 Make detach_pool_message visible for tools
Move there also vg_write and vg_commit.
2011-10-30 22:01:39 +00:00
Zdenek Kabelac
f8d46bd256 Thin cleanups
Fix/cleanup several error messages.
Remove test for seg_is_thin which could never be true there.
Replace (1<<24) with predefined constant.
2011-10-30 22:00:57 +00:00
Zdenek Kabelac
0968dfcd03 Thin support for stripe
Support stripe options to create thin data pool LV.

TODO: combine chunk size and stripe size.
2011-10-28 20:32:54 +00:00
Zdenek Kabelac
daa10ad0fd Thin pool resize support for data LV
Support for extension of pool data LV.

TODO: figure out thin volume for suspend/resume in cluster.
2011-10-28 20:31:01 +00:00
Zdenek Kabelac
e5b12b305f Thin support for lvrename
Rename pool's metadata lv _tmeta together with pool and _tdata.
2011-10-28 20:29:32 +00:00
Zdenek Kabelac
a1d5aaf725 Thin pool activation change
To ensure we properly handle LV cluster locking - explicitely do
not allow to change the availability of the thin pool that is in use
for some thin LV.

As soon as the thin volume is created the only way to activate pool
is via implicit dependency.

Ignore thinpool open count for lv/vgchange operations.
2011-10-28 20:28:00 +00:00
Zdenek Kabelac
2b71bcd0cb Improve lv_extend stack reporting
and some code cleanup with setting return value.
2011-10-28 20:23:24 +00:00
Zdenek Kabelac
c590a9cdbc Thin error messages clenaup and some indent 2011-10-28 20:19:26 +00:00
Zdenek Kabelac
dd3bb2bac3 Remove thin code from mirror/raid lv_extend 2011-10-28 20:18:32 +00:00
Zdenek Kabelac
2fa836e843 Extend virtual segment instead of adding new one
Before adding a new virtual segment to LV, check first whether
the last segment isn't already of the same type. In this case
extend last segment instead of creating the new one.

Thin volumes should have always only 1 virtual segment, but it
helps also to virtual snapshot or error segtype..
2011-10-28 20:17:55 +00:00
Zdenek Kabelac
bd4b840879 Add last_seg
Implement a function to return the last segment in a LV.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2011-10-28 20:12:54 +00:00
Jonathan Earl Brassow
682309e0b8 Disallow 'mirrored' log for cluster mirrors.
Git commit ID 0864378250 was meant to disallow
'mirrored' logs for cluster mirrors.  However, when add_mirror_log is used
to create the log (as is now the case when using 'lvcreate' or converting only
the log) the check is bypassed.

This patch adds the check to add_mirror_log.
2011-10-25 13:17:04 +00:00
Zdenek Kabelac
eafbdf3029 Don't print char type[8] as a plain string
pvck prints 'extra' character from the label since there is no '\0'
after the struct label entry and just uint64_t follows directly.
So avoid it by limiting 8 chars to be printed.

https://www.redhat.com/archives/lvm-devel/2011-January/msg00109.html

Signed-off-by: Paul Bolle <pebolle tiscali nl>
2011-10-24 10:24:39 +00:00
Zdenek Kabelac
72ff89d279 Always use vg memory pool for allocated lv segment
Remove mem pool parameter from alloc_lv_segment()
Since we should always allocate LV segment from the vg mempool.
2011-10-23 16:02:01 +00:00
Zdenek Kabelac
aef13649ea Remove old thin code from _lv_insert_empty_sublvs
Since thin is not able to use _lv_insert_empty_sublvs,
remove its appearence from this function.

Start to use extend_pool() function for desired functionality
and modify lv_extend() for this.
2011-10-22 16:48:59 +00:00
Zdenek Kabelac
dc225f58a9 Remove extra empty check
dm_list_splice handles empty list itself, no need to duplicate code.
2011-10-22 16:46:34 +00:00
Zdenek Kabelac
f4c77bd0e3 Recoded way to insert thin pool into vg
Code in _lv_insert_empty_sublvs  was not able to provide proper
initialization order for thin pool LV.

New function extend_pool() first adds metadata segment to pool LV which
is still visible. Such LV is activate and cleared.

Then new meta LV is created and metadata segments are moved there.
Now the preallocated pool data segment is attached to the pool LV
and layer _tpool is created. Finaly segment is marked as thin_pool.
2011-10-22 16:44:23 +00:00
Zdenek Kabelac
06b8248d63 Make move_lv_segment non-static
This function could be useful for other _manip source files.

Use dm_list manipulation function for provided functionality,
which make the code more readable and avoid touching list
internal details here.
2011-10-22 16:42:10 +00:00
Zdenek Kabelac
f0c9160df4 Store transaction_id with created thin lv
So we know the creation history and this should be useful with vgcfgrestore.
2011-10-21 11:38:35 +00:00
Zdenek Kabelac
4d925f5785 Remove double-hack for setting metadata size
Drop the second lv_extend and set 128MB directly in the first hack place.
2011-10-21 09:55:50 +00:00
Zdenek Kabelac
3bc417488d Thin pool now support chunk size as well
Use chunksize option to specify data_block_size for thin pool target.
Drop low_water_mark to zero.
2011-10-21 09:55:07 +00:00
Zdenek Kabelac
22f40c4efe Ensure right activation order
Couple FIXMEs put into the code for parts of the code which may be
improved later, since we might be able to add 'lazy' device creation later.
For now require exclusive activation.
2011-10-20 10:35:14 +00:00
Zdenek Kabelac
3f53c059e9 Add _BLOCK_ to define
Use DM_THIN_MIN_DATA_BLOCK_SIZE and
DM_THIN_MAX_DATA_BLOCK_SIZE to make it more obvious, for which
this define is useful in thin API.
2011-10-20 10:28:41 +00:00
Zdenek Kabelac
759b9592ba Update error message
Drop INTERNAL_ERROR from public API functions.
Improve some messages.
2011-10-19 16:42:14 +00:00
Zdenek Kabelac
8de912b677 Simple validation of messages in mda
Check we do not combine multiple messages for same LV target
and switch to use  'delete_id' to make it clear for what this device_id
is being used.
2011-10-19 16:39:09 +00:00
Zdenek Kabelac
3dcce042f6 Drop messages referencing deleted LV
lvremove may remove problematic LV for thin target.
2011-10-19 16:37:30 +00:00
Zdenek Kabelac
97d0f72c92 Just indent changes
Some tabs & spaces.
2011-10-19 16:36:39 +00:00
Zdenek Kabelac
b04e977851 Remove test for thin_pool
Since both functions are called during mda read - we don't have full LV info
at this moment.
2011-10-19 16:32:34 +00:00
Zdenek Kabelac
a25434a3a3 Message support for thin provisiong
lvm part of messaging.

Each message is now stored it's own thin pool section:

message1 {
	create = lv
}

Messages are queued to thin pool dm target when this target
is going to be resumed or used through some dependency.

Currently  'delete' message are purely queued and processed
with next thin pool resume operation (i.e. create_thin).

WARNING - thin provisioning support is developmental code.
2011-10-17 14:17:09 +00:00
Jonathan Earl Brassow
a551de6152 Use a more correct macro for 'seg_is_linear'
It is better to check 'seg->area_count == 1' than '!seg->stripe_size'.
2011-10-14 14:21:32 +00:00
Zdenek Kabelac
d4f134b8f6 Check for refresh_filter failure
Properly detect if the filters were refreshed properly.

(May needs few more fixes ??)

Filter refresh may fail because it may be out of free file descriptors
when clvmd gets overloaded.
2011-10-11 09:09:00 +00:00
Jonathan Earl Brassow
f60175c308 Add the ability to convert LVs of "mirror" segtype to "raid1" segtype.
Example:
~> lvconvert --type raid1 vg/mirror_lv

Steps to convert "mirror" to "raid1"
1) Allocate a RAID metadata LV for each mirror image from the same PVs
   on which they are located.
2) Clear the metadata LVs.  This involves writing LVM metadata, so we don't
   change any aspects of the mirror LV before this so that the user can easily
   remove LVs from the failed convert attempt while retaining the original
   mirror.
3) Remove the mirror log, if it exists.
4) Add metadata LVs to mirror LV
5) Rename mirror sub-lvs (s/mimage/rimage/)
6) Change flags and segtype from mirror to raid1
2011-10-07 14:56:01 +00:00
Jonathan Earl Brassow
d3582e0252 Add the ability to convert linear LVs to RAID1
Example:
~> lvconvert --type raid1 -m 1 vg/lv

The following steps are performed to convert linear to RAID1:
1) Allocate a metadata device from the same PV as the linear device
   to provide the metadata/data LV pair required for all RAID components.
2) Allocate the required number of metadata/data LV pairs for the
   remaining additional images.
3) Clear the metadata LVs.  This performs a LVM metadata update.
4) Create the top-level RAID LV and add the component devices.

We want to make any failure easy to unwind.  This is why we don't create the
top-level LV and add the components until the last step.  Should anything
happen before that, the user could simply remove the unnecessary images.  Also,
we want to ensure that the metadata LVs are cleared before forming the array to
prevent stale information from polluting the new array.

A new macro 'seg_is_linear' was added to allow us to distinguish linear LVs
from striped LVs.
2011-10-07 14:52:26 +00:00
Jonathan Earl Brassow
a80192b6a7 Allow 'nosync' extension of mirrors.
This patch allows a mirror to be extended without an initial resync of the
extended portion.  It compliments the existing '--nosync' option to lvcreate.
This action can be done implicitly if the mirror was created with the '--nosync'
option, or explicitly if the '--nosync' option is used when extending the device.

Here are the operational criteria:
1) A mirror created with '--nosync' should extend with 'nosync' implicitly
[EXAMPLE]# lvs vg; lvextend -L +5G vg/lv ; lvs vg
  LV   VG   Attr     LSize Pool Origin Snap%  Move Log     Copy%  Convert
  lv   vg   Mwi-a-m- 5.00g                         lv_mlog 100.00
  Extending 2 mirror images.
  Extending logical volume lv to 10.00 GiB
  Logical volume lv successfully resized
  LV   VG   Attr     LSize  Pool Origin Snap%  Move Log     Copy%  Convert
  lv   vg   Mwi-a-m- 10.00g                         lv_mlog 100.00

2) The 'M' attribute ('M' signifies a mirror created with '--nosync', while 'm'
signifies a mirror created w/o '--nosync') must be preserved when extending a
mirror created with '--nosync'.  See #1 for example of 'M' attribute.

3) A mirror created without '--nosync' should extend with 'nosync' only when
'--nosync' is explicitly used when extending.
[EXAMPLE]# lvs vg; lvextend -L +5G vg/lv; lvs vg
  LV   VG   Attr     LSize  Pool Origin Snap%  Move Log     Copy%  Convert
  lv   vg   mwi-a-m- 20.00m                         lv_mlog 100.00
  Extending 2 mirror images.
  Extending logical volume lv to 5.02 GiB
  Logical volume lv successfully resized
  LV   VG   Attr     LSize Pool Origin Snap%  Move Log     Copy%  Convert
  lv   vg   mwi-a-m- 5.02g                         lv_mlog   0.39
vs.
[EXAMPLE]# lvs vg; lvextend -L +5G vg/lv --nosync; lvs vg
  LV   VG   Attr     LSize  Pool Origin Snap%  Move Log     Copy%  Convert
  lv   vg   mwi-a-m- 20.00m                         lv_mlog 100.00
  Extending 2 mirror images.
  Extending logical volume lv to 5.02 GiB
  Logical volume lv successfully resized
  LV   VG   Attr     LSize Pool Origin Snap%  Move Log     Copy%  Convert
  lv   vg   Mwi-a-m- 5.02g                         lv_mlog 100.00

4) The 'm' attribute must change to 'M' when extending a mirror created without
'--nosync' is extended with the '--nosync' option.  (See #3 examples above.)

5) An inactive mirror's sync percent cannot be determined definitively, so it
must not be allowed to skip resync.  Instead, the extend should ask the user if
they want to extend while performing a resync.
[EXAMPLE]# lvchange -an vg/lv
[EXAMPLE]# lvextend -L +5G vg/lv
  Extending 2 mirror images.
  Extending logical volume lv to 10.00 GiB
  vg/lv is not active.  Unable to get sync percent.
Do full resync of extended portion of vg/lv?  [y/n]: y
  Logical volume lv successfully resized

6) A mirror that is performing recovery (as opposed to an initial sync) - like
after a failure - is not allowed to extend with either an implicit or
explicit nosync option.  [You can simulate this with a 'corelog' mirror because
when it is reactivated, it must be recovered every time.]
[EXAMPLE]# lvcreate -m1 -L 5G -n lv vg --nosync --corelog
  WARNING: New mirror won't be synchronised. Don't read what you didn't write!
  Logical volume "lv" created
[EXAMPLE]# lvs vg
  LV   VG   Attr     LSize Pool Origin Snap%  Move Log Copy%  Convert
  lv   vg   Mwi-a-m- 5.00g                             100.00
[EXAMPLE]# lvchange -an vg/lv; lvchange -ay vg/lv; lvs vg
  LV   VG   Attr     LSize Pool Origin Snap%  Move Log Copy%  Convert
  lv   vg   Mwi-a-m- 5.00g                               0.08
[EXAMPLE]# lvextend -L +5G vg/lv
  Extending 2 mirror images.
  Extending logical volume lv to 10.00 GiB
  vg/lv cannot be extended while it is recovering.

7) If 'no' is selected in #5 or if the condition in #6 is hit, it should not
result in the mirror being resized or the 'm/M' attribute being changed.


NOTE:  A mirror created with '--nosync' behaves differently than one created
without it when performing an extension.  The former cannot be extended when
the mirror is recovering (unless in-active), while the latter can.  This is
a reasonable thing to do since recovery of a mirror doesn't take long (at
least in the case of an on-disk log) and it would cause far more time in
degraded mode if the extension w/o '--nosync' was allowed.  It might be
reasonable to add the ability to force the operation in the future.  This
should /not/ force a nosync extension, but rather force a sync'ed extension.
IOW, the user would be saying, "Yes, yes... I know recovery won't take long
and that I'll be adding significantly to the time spent in degraded mode, but
I need the extra space right now!".
2011-10-06 15:32:26 +00:00