[lvm-devel] master - metadata: add infrastructure to track LV history
Peter Rajnoha
prajnoha at fedoraproject.org
Thu Mar 3 13:19:29 UTC 2016
Gitweb: http://git.fedorahosted.org/git/?p=lvm2.git;a=commitdiff;h=e573eca554374ba6889a7f89fcb9850ae13c793e
Commit: e573eca554374ba6889a7f89fcb9850ae13c793e
Parent: 5e718ec66679aad42773901a40e168ba4c3f3f50
Author: Peter Rajnoha <prajnoha at redhat.com>
AuthorDate: Tue Mar 1 15:18:42 2016 +0100
Committer: Peter Rajnoha <prajnoha at redhat.com>
CommitterDate: Thu Mar 3 11:26:51 2016 +0100
metadata: add infrastructure to track LV history
Add new structures and new fields in existing structures to support
tracking history of LVs (the LVs which don't exist - the have been
removed already):
- new "struct historical_logical_volume"
This structure keeps information specific to historical LVs
(historical LV is very reduced form of struct logical_volume +
it contains a few specific fields to track historical LV
properties like removal time and connections among other LVs).
- new "struct generic_logical_volume"
Wrapper for "struct historical_logical_volume" and
"struct logical_volume" to make it possible to handle volumes
in uniform way, no matter if it's live or historical one.
- new "struct glv_list"
Wrapper for "struct generic_logical_volume" so it can be
added to a list.
- new "indirect_glvs" field in "struct logical_volume"
List that stores references to all indirect users of this LV - this
interconnects live LV with historical descendant LVs or even live
descendant LVs.
- new "indirect_origin" field in "struct lv_segment"
Reference to indirect origin of this segment - this interconnects
live LV (segment) with historical ancestor.
- new "this_glv" field in "struct logical_volume"
This references an existing generic_logical_volume wrapper for this
LV, if used. It can be NULL if not needed - which means we're not
handling historical LVs at all.
- new "historical_lvs" field in "struct volume group
List of all historical LVs read from VG metadata.
---
lib/metadata/lv.h | 48 ++++++++++++++++++++++++++++++++++++++
lib/metadata/lv_manip.c | 1 +
lib/metadata/metadata-exported.h | 6 ++++
lib/metadata/vg.c | 1 +
lib/metadata/vg.h | 1 +
lib/report/report.c | 2 +
tools/reporter.c | 2 +
7 files changed, 61 insertions(+), 0 deletions(-)
diff --git a/lib/metadata/lv.h b/lib/metadata/lv.h
index 4b42eb7..f554bce 100644
--- a/lib/metadata/lv.h
+++ b/lib/metadata/lv.h
@@ -49,6 +49,15 @@ struct logical_volume {
struct dm_list segments;
struct dm_list tags;
struct dm_list segs_using_this_lv;
+ struct dm_list indirect_glvs; /* For keeping track of historical LVs in ancestry chain */
+
+ /*
+ * this_glv variable is used as a helper for handling historical LVs.
+ * If this LVs has no role at all in keeping track of historical LVs,
+ * the this_glv variable is NULL. See also comments for struct
+ * generic_logical_volume and struct historical_logical_volume below.
+ */
+ struct generic_logical_volume *this_glv;
uint64_t timestamp;
unsigned new_lock_args:1;
@@ -56,6 +65,45 @@ struct logical_volume {
const char *lock_args;
};
+/*
+ * With the introduction of tracking historical LVs, we need to make
+ * a difference between live LV (struct logical_volume) and historical LV
+ * (struct historical_logical_volume). To minimize the impact of this change
+ * and to minimize the changes needed in the existing code, we use a
+ * little trick here - when processing LVs (e.g. while reporting LV
+ * properties), each historical LV is represented as dummy LV which is
+ * an instance of struct logical_volume with all its properties set to
+ * blank (hence "dummy LV") and with this_glv pointing to the struct
+ * historical_logical_volume. This way all the existing code working with
+ * struct logical_volume will see this historical LV as dummy live LV while
+ * the code that needs to recognize between live and historical LV will
+ * check this_glv first and then it will work either with the live
+ * or historical LV properties appropriately.
+ */
+struct generic_logical_volume;
+
+/*
+ * historical logical volume is an LV that has been removed already.
+ * This is used to keep track of LV history.
+ */
+struct historical_logical_volume {
+ union lvid lvid;
+ const char *name;
+ struct volume_group *vg;
+ uint64_t timestamp;
+ uint64_t timestamp_removed;
+ struct generic_logical_volume *indirect_origin;
+ struct dm_list indirect_glvs; /* list of struct generic_logical_volume */
+};
+
+struct generic_logical_volume {
+ int is_historical;
+ union {
+ struct logical_volume *live; /* is_historical=0 */
+ struct historical_logical_volume *historical; /* is_historical=1 */
+ };
+};
+
struct lv_with_info_and_seg_status;
/* LV dependencies */
diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c
index 1b431c1..069042c 100644
--- a/lib/metadata/lv_manip.c
+++ b/lib/metadata/lv_manip.c
@@ -5320,6 +5320,7 @@ struct logical_volume *alloc_lv(struct dm_pool *mem)
dm_list_init(&lv->segments);
dm_list_init(&lv->tags);
dm_list_init(&lv->segs_using_this_lv);
+ dm_list_init(&lv->indirect_glvs);
dm_list_init(&lv->rsites);
return lv;
diff --git a/lib/metadata/metadata-exported.h b/lib/metadata/metadata-exported.h
index 8376a54..97cba51 100644
--- a/lib/metadata/metadata-exported.h
+++ b/lib/metadata/metadata-exported.h
@@ -447,6 +447,7 @@ struct lv_segment {
uint32_t chunk_size; /* For snapshots/thin_pool. In sectors. */
/* For thin_pool, 128..2097152. */
struct logical_volume *origin; /* snap and thin */
+ struct generic_logical_volume *indirect_origin;
struct logical_volume *merge_lv; /* thin, merge descendent lv into this ancestor */
struct logical_volume *cow;
struct dm_list origin_list;
@@ -505,6 +506,11 @@ struct lv_list {
struct logical_volume *lv;
};
+struct glv_list {
+ struct dm_list list;
+ struct generic_logical_volume *glv;
+};
+
struct vg_list {
struct dm_list list;
struct volume_group *vg;
diff --git a/lib/metadata/vg.c b/lib/metadata/vg.c
index 1456fbb..90c459e 100644
--- a/lib/metadata/vg.c
+++ b/lib/metadata/vg.c
@@ -64,6 +64,7 @@ struct volume_group *alloc_vg(const char *pool_name, struct cmd_context *cmd,
dm_list_init(&vg->pv_write_list);
dm_list_init(&vg->pvs_outdated);
dm_list_init(&vg->lvs);
+ dm_list_init(&vg->historical_lvs);
dm_list_init(&vg->tags);
dm_list_init(&vg->removed_lvs);
dm_list_init(&vg->removed_pvs);
diff --git a/lib/metadata/vg.h b/lib/metadata/vg.h
index f41def8..c5197cb 100644
--- a/lib/metadata/vg.h
+++ b/lib/metadata/vg.h
@@ -128,6 +128,7 @@ struct volume_group {
* - one for the user-visible mirror LV
*/
struct dm_list lvs;
+ struct dm_list historical_lvs;
struct dm_list tags;
diff --git a/lib/report/report.c b/lib/report/report.c
index 43987b1..056afd2 100644
--- a/lib/report/report.c
+++ b/lib/report/report.c
@@ -3386,6 +3386,7 @@ static struct volume_group _dummy_vg = {
.lvm1_system_id = (char *) "",
.pvs = DM_LIST_HEAD_INIT(_dummy_vg.pvs),
.lvs = DM_LIST_HEAD_INIT(_dummy_vg.lvs),
+ .historical_lvs = DM_LIST_HEAD_INIT(_dummy_vg.historical_lvs),
.tags = DM_LIST_HEAD_INIT(_dummy_vg.tags),
};
@@ -3396,6 +3397,7 @@ static struct volume_group _unknown_vg = {
.lvm1_system_id = (char *) "",
.pvs = DM_LIST_HEAD_INIT(_unknown_vg.pvs),
.lvs = DM_LIST_HEAD_INIT(_unknown_vg.lvs),
+ .historical_lvs = DM_LIST_HEAD_INIT(_unknown_vg.historical_lvs),
.tags = DM_LIST_HEAD_INIT(_unknown_vg.tags),
};
diff --git a/tools/reporter.c b/tools/reporter.c
index 1a24698..0c73a09 100644
--- a/tools/reporter.c
+++ b/tools/reporter.c
@@ -244,6 +244,7 @@ static int _do_pvsegs_sub_single(struct cmd_context *cmd,
.name = "",
.pvs = DM_LIST_HEAD_INIT(_free_vg.pvs),
.lvs = DM_LIST_HEAD_INIT(_free_vg.lvs),
+ .historical_lvs = DM_LIST_HEAD_INIT(_free_vg.historical_lvs),
.tags = DM_LIST_HEAD_INIT(_free_vg.tags),
};
@@ -256,6 +257,7 @@ static int _do_pvsegs_sub_single(struct cmd_context *cmd,
.tags = DM_LIST_HEAD_INIT(_free_logical_volume.tags),
.segments = DM_LIST_HEAD_INIT(_free_logical_volume.segments),
.segs_using_this_lv = DM_LIST_HEAD_INIT(_free_logical_volume.segs_using_this_lv),
+ .indirect_glvs = DM_LIST_HEAD_INIT(_free_logical_volume.indirect_glvs),
.snapshot_segs = DM_LIST_HEAD_INIT(_free_logical_volume.snapshot_segs),
};
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