Btrfs: search parity device wisely
After mapping block with BTRFS_MAP_WRITE, parities have been sorted to
the end position, so this search can start from the first parity
stripe.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ copied changelog as a comment ]
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 24a6222..cba5e73 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -2231,12 +2231,18 @@ raid56_parity_alloc_scrub_rbio(struct btrfs_fs_info *fs_info, struct bio *bio,
ASSERT(!bio->bi_iter.bi_size);
rbio->operation = BTRFS_RBIO_PARITY_SCRUB;
- for (i = 0; i < rbio->real_stripes; i++) {
+ /*
+ * After mapping bbio with BTRFS_MAP_WRITE, parities have been sorted
+ * to the end position, so this search can start from the first parity
+ * stripe.
+ */
+ for (i = rbio->nr_data; i < rbio->real_stripes; i++) {
if (bbio->stripes[i].dev == scrub_dev) {
rbio->scrubp = i;
break;
}
}
+ ASSERT(i < rbio->real_stripes);
/* Now we just support the sectorsize equals to page size */
ASSERT(fs_info->sectorsize == PAGE_SIZE);