1 files changed, 10 insertions, 1 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 3f048bd6326d..5a8f55fea5ff 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1269,9 +1269,18 @@ repeat:
 
         /* Some devices return the total number of sectors, not the
          * highest sector number.  Make the necessary adjustment. */
-        if (sdp->fix_capacity)
+        if (sdp->fix_capacity) {
                 --sdkp->capacity;
 
+        /* Some devices have version which report the correct sizes
+         * and others which do not. We guess size according to a heuristic
+         * and err on the side of lowering the capacity. */
+        } else {
+                if (sdp->guess_capacity)
+                        if (sdkp->capacity & 0x01) /* odd sizes are odd */
+                                --sdkp->capacity;
+        }
+
 got_data:
         if (sector_size == 0) {
                 sector_size = 512;