writecache: display block size from lvs

lvs was missing the ability to display writecache block size.
now possible with lvs -o writecache_block_size

5 files changed, 29 insertions, 0 deletions

diff --git a/lib/report/columns.h b/lib/report/columns.h
index 12b78b766..7e450dace 100644
--- a/lib/report/columns.h
+++ b/lib/report/columns.h
@@ -108,6 +108,7 @@ FIELD(LVS, lv, TIM, "RTime", lvid, 26, lvtimeremoved, lv_time_removed, "Removal
 FIELD(LVS, lv, STR, "Host", lvid, 10, lvhost, lv_host, "Creation host of the LV, if known.", 0)
 FIELD(LVS, lv, STR_LIST, "Modules", lvid, 0, modules, lv_modules, "Kernel device-mapper modules required for this LV.", 0)
 FIELD(LVS, lv, BIN, "Historical", lvid, 0, lvhistorical, lv_historical, "Set if the LV is historical.", 0)
+FIELD(LVS, lv, NUM, "WCacheBlkSize", lvid, 0, writecache_block_size, writecache_block_size, "The writecache block size", 0)
 /*
  * End of LVS type fields
  */
diff --git a/lib/report/properties.c b/lib/report/properties.c
index 12ea890f4..6f302360f 100644
--- a/lib/report/properties.c
+++ b/lib/report/properties.c
@@ -353,6 +353,8 @@ GET_PV_STR_PROPERTY_FN(pv_device_id_type, pv->device_id_type)
 #define _writecache_writeback_blocks_get prop_not_implemented_get
 #define _writecache_error_set prop_not_implemented_set
 #define _writecache_error_get prop_not_implemented_get
+#define _writecache_block_size_set prop_not_implemented_set
+#define _writecache_block_size_get prop_not_implemented_get
 
 #define _vdo_operating_mode_set prop_not_implemented_set
 #define _vdo_operating_mode_get prop_not_implemented_get
diff --git a/lib/report/report.c b/lib/report/report.c
index 60df417a4..c06b22674 100644
--- a/lib/report/report.c
+++ b/lib/report/report.c
@@ -3346,6 +3346,26 @@ static int _integritymismatches_disp(struct dm_report *rh __attribute__((unused)
 	return _field_set_value(field, "", &GET_TYPE_RESERVED_VALUE(num_undef_64));
 }
 
+static int _writecache_block_size_disp(struct dm_report *rh __attribute__((unused)),
+				   struct dm_pool *mem,
+				   struct dm_report_field *field,
+				   const void *data,
+				   void *private __attribute__((unused)))
+{
+	struct logical_volume *lv = (struct logical_volume *) data;
+	uint32_t bs = 0;
+
+	if (lv_is_writecache(lv)) {
+		struct lv_segment *seg = first_seg(lv);
+		bs = seg->writecache_block_size;
+	}
+
+	if (!bs)
+		return dm_report_field_int32(rh, field, &GET_TYPE_RESERVED_VALUE(num_undef_32));
+
+	return dm_report_field_uint32(rh, field, &bs);
+}
+
 static int _datapercent_disp(struct dm_report *rh, struct dm_pool *mem,
 			     struct dm_report_field *field,
 			     const void *data, void *private)
diff --git a/man/lvmcache.7_main b/man/lvmcache.7_main
index 73680235b..519e352cb 100644
--- a/man/lvmcache.7_main
+++ b/man/lvmcache.7_main
@@ -241,6 +241,10 @@ It is also possible to specify a sector size of 4096 to mkfs.xfs when
 creating the file system.  In this case the writecache block size of 4096
 can be used.
 .P
+The writecache block size is displayed by the command:
+.br
+lvs -o writecacheblocksize VG/LV
+.P
 .SS dm-writecache memory usage
 .P
 The amount of main system memory used by dm-writecache can be a factor
diff --git a/test/shell/writecache-cache-blocksize.sh b/test/shell/writecache-cache-blocksize.sh
index 2579ef7b7..4e17effe5 100644
--- a/test/shell/writecache-cache-blocksize.sh
+++ b/test/shell/writecache-cache-blocksize.sh
@@ -222,6 +222,8 @@ vgextend $vg "$dev2"
 lvcreate -n $lv1 -l 8 -an $vg "$dev1"
 lvcreate -n $lv2 -l 4 -an $vg "$dev2"
 lvconvert --yes --type writecache --cachevol $lv2 --cachesettings "block_size=4096" $vg/$lv1
+lvs -o writecacheblocksize $vg/$lv1 |tee out
+grep 4096 out
 lvchange -ay $vg/$lv1
 mkfs.xfs -f "$DM_DEV_DIR/$vg/$lv1" |tee out
 grep "sectsz=4096" out