[lvm-devel] [RFC PATCH] lvm2app: List snapshot LV information for a given origin LV

M. Mohan Kumar mohan at in.ibm.com
Tue Oct 1 18:24:42 UTC 2013


From: "M. Mohan Kumar" <mohan at in.ibm.com>

Similar to origin property list snapshot information for a given LV.
Also this feature extended to lvs command.

lvs -oname,snapshot displays name of the LV and snapshot LV name if any.

lvm2app enhanced to support the property "lv_snapshot", the call
lvm_lv_get_property(lv, "lv_snapshot") returns list of snapshot for
given lv 'lv'.

Signed-off-by: M. Mohan Kumar <mohan at in.ibm.com>
---
For Block Device xlator work, its better to support providing list of
snapshots for a given origin LV. This feature will be exploited by BD
xlator to list out snapshots for a given origin LV.

 lib/metadata/lv.c       |  5 +++++
 lib/metadata/lv.h       |  1 +
 lib/metadata/metadata.c | 26 ++++++++++++++++++++++++++
 lib/metadata/metadata.h |  1 +
 lib/report/columns.h    |  1 +
 lib/report/properties.c |  2 ++
 lib/report/report.c     | 16 ++++++++++++++++
 7 files changed, 52 insertions(+)

diff --git a/lib/metadata/lv.c b/lib/metadata/lv.c
index db71cf0..216fd99 100644
--- a/lib/metadata/lv.c
+++ b/lib/metadata/lv.c
@@ -378,6 +378,11 @@ char *lv_tags_dup(const struct logical_volume *lv)
 	return tags_format_and_copy(lv->vg->vgmem, &lv->tags);
 }
 
+char *lv_snapshot_dup(const struct logical_volume *lv)
+{
+	return list_snapshot(lv->vg->vgmem, &lv->snapshot_segs);
+}
+
 uint64_t lv_size(const struct logical_volume *lv)
 {
 	return lv->size;
diff --git a/lib/metadata/lv.h b/lib/metadata/lv.h
index 06f8c60..0da81ef 100644
--- a/lib/metadata/lv.h
+++ b/lib/metadata/lv.h
@@ -94,4 +94,5 @@ const struct logical_volume *lv_lock_holder(const struct logical_volume *lv);
 struct logical_volume *lv_ondisk(struct logical_volume *lv);
 struct profile *lv_config_profile(const struct logical_volume *lv);
 char *lv_profile_dup(struct dm_pool *mem, const struct logical_volume *lv);
+char *lv_snapshot_dup(const struct logical_volume *lv);
 #endif /* _LVM_LV_H */
diff --git a/lib/metadata/metadata.c b/lib/metadata/metadata.c
index 4ae7726..7753def 100644
--- a/lib/metadata/metadata.c
+++ b/lib/metadata/metadata.c
@@ -4629,6 +4629,32 @@ char *tags_format_and_copy(struct dm_pool *mem, const struct dm_list *tags)
 	return dm_pool_end_object(mem);
 }
 
+char *list_snapshot(struct dm_pool *mem, const struct dm_list *snap)
+{
+	struct str_list *sl;
+	char *c = NULL;
+	struct lv_segment *snap_seg;
+
+	if (!dm_pool_begin_object(mem, 256)) {
+		log_error("dm_pool_begin_object failed");
+		return NULL;
+	}
+	dm_list_iterate_items_gen(snap_seg, snap, origin_list) {
+		if (!dm_pool_grow_object(mem, snap_seg->cow->name,
+					 strlen(snap_seg->cow->name)) ||
+		    (!dm_pool_grow_object(mem, ",", 1))) {
+			log_error("dm_pool_grow_object failed");
+			return NULL;
+		}
+	}
+
+	if (!dm_pool_grow_object(mem, "\0", 1)) {
+		log_error("dm_pool_grow_object failed");
+		return NULL;
+	}
+	return dm_pool_end_object(mem);
+}
+
 struct logical_volume *lv_ondisk(struct logical_volume *lv)
 {
 	struct volume_group *vg;
diff --git a/lib/metadata/metadata.h b/lib/metadata/metadata.h
index 2408c23..e998534 100644
--- a/lib/metadata/metadata.h
+++ b/lib/metadata/metadata.h
@@ -485,6 +485,7 @@ int add_pv_to_vg(struct volume_group *vg, const char *pv_name,
 
 uint64_t find_min_mda_size(struct dm_list *mdas);
 char *tags_format_and_copy(struct dm_pool *mem, const struct dm_list *tags);
+char *list_snapshot(struct dm_pool *mem, const struct dm_list *tags);
 
 void check_reappeared_pv(struct volume_group *correct_vg,
 			 struct physical_volume *pv);
diff --git a/lib/report/columns.h b/lib/report/columns.h
index 9bb99d3..da09ddb 100644
--- a/lib/report/columns.h
+++ b/lib/report/columns.h
@@ -65,6 +65,7 @@ FIELD(LVS, lv, STR, "LProfile", lvid, 8, lvprofile, lv_profile, "Configuration p
 FIELD(LVS, lv, STR, "Time", lvid, 26, lvtime, lv_time, "Creation time of the LV, if known", 0)
 FIELD(LVS, lv, STR, "Host", lvid, 10, lvhost, lv_host, "Creation host of the LV, if known.", 0)
 FIELD(LVS, lv, STR, "Modules", lvid, 7, modules, lv_modules, "Kernel device-mapper modules required for this LV.", 0)
+FIELD(LVS, lv, STR, "snapshot", lvid, 8, snapshot, lv_snapshot, "Snapshots for this LV.", 0)
 
 FIELD(LABEL, pv, STR, "Fmt", id, 3, pvfmt, pv_fmt, "Type of metadata.", 0)
 FIELD(LABEL, pv, STR, "PV UUID", id, 38, uuid, pv_uuid, "Unique identifier.", 0)
diff --git a/lib/report/properties.c b/lib/report/properties.c
index 3eeb78a..2481c69 100644
--- a/lib/report/properties.c
+++ b/lib/report/properties.c
@@ -235,6 +235,8 @@ GET_LV_STR_PROPERTY_FN(lv_active, lv_active_dup(lv->vg->vgmem, lv))
 #define _lv_active_set prop_not_implemented_set
 GET_LV_STR_PROPERTY_FN(lv_profile, lv_profile_dup(lv->vg->vgmem, lv))
 #define _lv_profile_set prop_not_implemented_set
+GET_LV_STR_PROPERTY_FN(lv_snapshot, lv_snapshot_dup(lv))
+#define _lv_snapshot_set prop_not_implemented_set
 
 /* VG */
 GET_VG_STR_PROPERTY_FN(vg_fmt, vg_fmt_dup(vg))
diff --git a/lib/report/report.c b/lib/report/report.c
index 77332a2..2070a55 100644
--- a/lib/report/report.c
+++ b/lib/report/report.c
@@ -97,6 +97,21 @@ static int _tags_disp(struct dm_report *rh __attribute__((unused)), struct dm_po
 	return 1;
 }
 
+static int _snapshot_disp(struct dm_report *rh __attribute__((unused)), struct dm_pool *mem,
+		      struct dm_report_field *field,
+		      const void *data, void *private __attribute__((unused)))
+{
+	const struct logical_volume *lv = (const struct logical_volume *) data;
+	char *tags_str;
+
+	if (!(tags_str = list_snapshot(mem, &lv->snapshot_segs)))
+		return 0;
+
+	dm_report_field_set_value(field, tags_str, NULL);
+
+	return 1;
+}
+
 static int _modules_disp(struct dm_report *rh, struct dm_pool *mem,
 			 struct dm_report_field *field,
 			 const void *data, void *private)
@@ -124,6 +139,7 @@ static int _lvprofile_disp(struct dm_report *rh, struct dm_pool *mem,
 	return 1;
 }
 
+
 static int _vgfmt_disp(struct dm_report *rh, struct dm_pool *mem,
 		       struct dm_report_field *field,
 		       const void *data, void *private)
-- 
1.7.11.7




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