CA-35363: fix VHD metadata corruption introduced with cset 453:b86e2a0bbccd

diff --git a/drivers/block-vhd.c b/drivers/block-vhd.c
index ba984f2d12a26b0375e3c519a86809a7818c6228..9639c5225a813314552b966f0990cc67b65d9ba2 100644 (file)
--- a/drivers/block-vhd.c
+++ b/drivers/block-vhd.c
@@ -206,6 +206,7 @@ struct vhd_state {
        vhd_context_t             vhd;
        u32                       spp;         /* sectors per page */
         u32                       spb;         /* sectors per block */
+       u64                       first_db;    /* pointer to datablock 0 */
         u64                       next_db;     /* pointer to the next 
                                                * (unallocated) datablock */
 
@@ -366,6 +367,9 @@ find_next_free_block(struct vhd_state *s)
                return err;
 
        s->next_db = secs_round_up(eom);
+       s->first_db = s->next_db;
+       if ((s->first_db + s->bm_secs) % s->spp)
+               s->first_db += (s->spp - ((s->first_db + s->bm_secs) % s->spp));
 
        for (i = 0; i < s->bat.bat.entries; i++) {
                entry = bat_entry(s, i);
@@ -1600,7 +1604,7 @@ schedule_data_write(struct vhd_state *s, td_request_t treq, vhd_flag_t flags)
                        add_to_transaction(&bm->tx, req);
        } else if (sec == 0 &&  /* first sector inside data block */
                   s->vhd.footer.type != HD_TYPE_FIXED && 
-                  treq.sec > 0 && /* not the first block */
+                  bat_entry(s, blk) != s->first_db &&
                   test_batmap(s, blk))
                schedule_redundant_bm_write(s, blk);