dm snapshot: add allocated metadata to snapshot status

Add number of sectors used by metadata to the end of the snapshot's status
line.

Renamed dm_exception_store_type's 'fraction_full' to 'usage'.  Renamed
arguments to be clearer about what is being returned.  Also added
'metadata_sectors'.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 12 insertions, 9 deletions

diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index cb4c2c3a43f0..8bd77cbd7e45 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -1174,14 +1174,17 @@ static int snapshot_status(struct dm_target *ti, status_type_t type,
                 if (!snap->valid)
                         DMEMIT("Invalid");
                 else {
-                        if (snap->store->type->fraction_full) {
-                                sector_t numerator, denominator;
-                                snap->store->type->fraction_full(snap->store,
-                                                                 &numerator,
-                                                                 &denominator);
-                                DMEMIT("%llu/%llu",
-                                       (unsigned long long)numerator,
-                                       (unsigned long long)denominator);
+                        if (snap->store->type->usage) {
+                                sector_t total_sectors, sectors_allocated,
+                                         metadata_sectors;
+                                snap->store->type->usage(snap->store,
+                                                         &total_sectors,
+                                                         &sectors_allocated,
+                                                         &metadata_sectors);
+                                DMEMIT("%llu/%llu %llu",
+                                       (unsigned long long)sectors_allocated,
+                                       (unsigned long long)total_sectors,
+                                       (unsigned long long)metadata_sectors);
                         }
                         else
                                 DMEMIT("Unknown");
@@ -1462,7 +1465,7 @@ static struct target_type origin_target = {
 
 static struct target_type snapshot_target = {
         .name    = "snapshot",
-        .version = {1, 7, 0},
+        .version = {1, 8, 0},
         .module  = THIS_MODULE,
         .ctr     = snapshot_ctr,
         .dtr     = snapshot_dtr,