1 files changed, 20 insertions, 7 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 20f7e4ef5342..45abb54037fc 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1155,12 +1155,14 @@ void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors)
 EXPORT_SYMBOL_GPL(dm_accept_partial_bio);
 
 /*
- * The zone descriptors obtained with a zone report indicate
- * zone positions within the target device. The zone descriptors
- * must be remapped to match their position within the dm device.
- * A target may call dm_remap_zone_report after completion of a
- * REQ_OP_ZONE_REPORT bio to remap the zone descriptors obtained
- * from the target device mapping to the dm device.
+ * The zone descriptors obtained with a zone report indicate zone positions
+ * within the target backing device, regardless of that device is a partition
+ * and regardless of the target mapping start sector on the device or partition.
+ * The zone descriptors start sector and write pointer position must be adjusted
+ * to match their relative position within the dm device.
+ * A target may call dm_remap_zone_report() after completion of a
+ * REQ_OP_ZONE_REPORT bio to remap the zone descriptors obtained from the
+ * backing device.
  */
 void dm_remap_zone_report(struct dm_target *ti, struct bio *bio, sector_t start)
 {
@@ -1171,6 +1173,7 @@ void dm_remap_zone_report(struct dm_target *ti, struct bio *bio, sector_t start)
         struct blk_zone *zone;
         unsigned int nr_rep = 0;
         unsigned int ofst;
+        sector_t part_offset;
         struct bio_vec bvec;
         struct bvec_iter iter;
         void *addr;
@@ -1179,6 +1182,15 @@ void dm_remap_zone_report(struct dm_target *ti, struct bio *bio, sector_t start)
                 return;
 
         /*
+         * bio sector was incremented by the request size on completion. Taking
+         * into account the original request sector, the target start offset on
+         * the backing device and the target mapping offset (ti->begin), the
+         * start sector of the backing device. The partition offset is always 0
+         * if the target uses a whole device.
+         */
+        part_offset = bio->bi_iter.bi_sector + ti->begin - (start + bio_end_sector(report_bio));
+
+        /*
          * Remap the start sector of the reported zones. For sequential zones,
          * also remap the write pointer position.
          */
@@ -1195,6 +1207,7 @@ void dm_remap_zone_report(struct dm_target *ti, struct bio *bio, sector_t start)
                 /* Set zones start sector */
                 while (hdr->nr_zones && ofst < bvec.bv_len) {
                         zone = addr + ofst;
+                        zone->start -= part_offset;
                         if (zone->start >= start + ti->len) {
                                 hdr->nr_zones = 0;
                                 break;
@@ -1206,7 +1219,7 @@ void dm_remap_zone_report(struct dm_target *ti, struct bio *bio, sector_t start)
                                 else if (zone->cond == BLK_ZONE_COND_EMPTY)
                                         zone->wp = zone->start;
                                 else
-                                        zone->wp = zone->wp + ti->begin - start;
+                                        zone->wp = zone->wp + ti->begin - start - part_offset;
                         }
                         ofst += sizeof(struct blk_zone);
                         hdr->nr_zones--;