Patch name: lvm-use-new-split-capability.patch
Percolate the ability split off a leg up to the user.
[FIXME: This is just to illustrate things are working.
Getting consensus on CLI args will be the hard part. It
should be easy to adjust this patch when that is done.]
RFC: Jonathan Brassow <jbrassow@xxxxxxxxxx>
Index: LVM2/lib/metadata/mirror.c
===================================================================
--- LVM2.orig/lib/metadata/mirror.c
+++ LVM2/lib/metadata/mirror.c
@@ -1607,6 +1607,37 @@ int lv_add_mirrors(struct cmd_context *c
return 0;
}
+int lv_split_mirror_images(struct logical_volume *lv, uint32_t split_count,
+ struct dm_list *removable_pvs)
+{
+ int r;
+
+ /*
+ * Right now, we only allow the user to split a single
+ * leg off at a time. In the future, we might allow a
+ * 4-way mirror to be split into 2 2-way mirrors, but
+ * not right now.
+ */
+ if (split_count != 1) {
+ log_error("Unable to split more than one leg from a mirror.");
+ return_0;
+ }
+
+ /* Can't split a mirror that is not in-sync... unless force? */
+ if (!_mirrored_lv_in_sync(lv)) {
+ log_error("Unable to split mirror that is not in-sync.");
+ return_0;
+ }
+
+ r = _remove_mirror_images(lv, split_count,
+ removable_pvs, 0, 0, 1, NULL);
+ if (!r)
+ return 0;
+
+ /* Rename split leg here? */
+ return 1;
+}
+
/*
* Generic interface for removing mirror and/or mirror log.
* 'mirror' is the number of mirrors to be removed.
Index: LVM2/tools/args.h
===================================================================
--- LVM2.orig/tools/args.h
+++ LVM2/tools/args.h
@@ -49,6 +49,7 @@ arg(nosync_ARG, '\0', "nosync", NULL, 0)
arg(resync_ARG, '\0', "resync", NULL, 0)
arg(corelog_ARG, '\0', "corelog", NULL, 0)
arg(mirrorlog_ARG, '\0', "mirrorlog", string_arg, 0)
+arg(mirrorsplit_ARG, '\0', "split", NULL, 0)
arg(repair_ARG, '\0', "repair", NULL, 0)
arg(use_policies_ARG, '\0', "use-policies", NULL, 0)
arg(monitor_ARG, '\0', "monitor", yes_no_arg, 0)
Index: LVM2/tools/commands.h
===================================================================
--- LVM2.orig/tools/commands.h
+++ LVM2/tools/commands.h
@@ -122,8 +122,9 @@ xx(lvconvert,
"\tOriginalLogicalVolume[Path] SnapshotLogicalVolume[Path]\n",
alloc_ARG, background_ARG, chunksize_ARG, corelog_ARG, interval_ARG,
- mirrorlog_ARG, mirrors_ARG, noudevsync_ARG, regionsize_ARG, repair_ARG,
- snapshot_ARG, test_ARG, use_policies_ARG, yes_ARG, force_ARG, zero_ARG)
+ mirrorsplit_ARG, mirrorlog_ARG, mirrors_ARG, noudevsync_ARG,
+ regionsize_ARG, repair_ARG, snapshot_ARG, test_ARG, use_policies_ARG,
+ yes_ARG, force_ARG, zero_ARG)
xx(lvcreate,
"Create a logical volume",
Index: LVM2/tools/lvconvert.c
===================================================================
--- LVM2.orig/tools/lvconvert.c
+++ LVM2/tools/lvconvert.c
@@ -30,6 +30,8 @@ struct lvconvert_params {
uint32_t chunk_size;
uint32_t region_size;
+ int split;
+ int track_deltas;
uint32_t mirrors;
sign_t mirrors_sign;
@@ -125,6 +127,7 @@ static int _read_params(struct lvconvert
lp->snapshot = 1;
if (arg_count(cmd, mirrors_ARG)) {
+ lp->split = arg_count(cmd, mirrorsplit_ARG) ? 1 :0;
lp->mirrors = arg_uint_value(cmd, mirrors_ARG, 0);
lp->mirrors_sign = arg_sign_value(cmd, mirrors_ARG, 0);
}
@@ -681,10 +684,16 @@ static int _lvconvert_mirrors(struct cmd
/* Reduce number of mirrors */
if (repair || lp->pv_count)
remove_pvs = lp->pvh;
- if (!lv_remove_mirrors(cmd, lv, existing_mirrors - lp->mirrors,
- (!log_count || lp->mirrors == 1) ? 1U : 0U,
- remove_pvs, 0))
+
+ if (lp->split) {
+ if (!lv_split_mirror_images(lv, existing_mirrors - lp->mirrors,
+ remove_pvs))
+ return 0;
+ } else if (!lv_remove_mirrors(cmd, lv, existing_mirrors - lp->mirrors,
+ (!log_count || lp->mirrors == 1) ? 1U : 0U,
+ remove_pvs, 0))
return_0;
+
if (lp->mirrors > 1 &&
!_lv_update_log_type(cmd, lp, lv, log_count))
return_0;
Index: LVM2/lib/metadata/metadata-exported.h
===================================================================
--- LVM2.orig/lib/metadata/metadata-exported.h
+++ LVM2/lib/metadata/metadata-exported.h
@@ -648,6 +648,8 @@ int lv_add_mirrors(struct cmd_context *c
uint32_t mirrors, uint32_t stripes,
uint32_t region_size, uint32_t log_count,
struct dm_list *pvs, alloc_policy_t alloc, uint32_t flags);
+int lv_split_mirror_images(struct logical_volume *lv, uint32_t split_count,
+ struct dm_list *removable_pvs);
int lv_remove_mirrors(struct cmd_context *cmd, struct logical_volume *lv,
uint32_t mirrors, uint32_t log_count,
struct dm_list *pvs, uint32_t status_mask);
--
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