In __btrfs_map_block(), stripe_index is always wrong if mirror_num is given. For DUP/RAID1 case, if mirror_num is given, e.g. 1, it should return the second stripe. But codes consider the mirror_num is start from 1 and always minus 1, causing even mirror number is given as 1, __btrfs_map_block() will still map the first stripe not the second. Signed-off-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx> --- volumes.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/volumes.c b/volumes.c index 16dbf64..c66c02a 100644 --- a/volumes.c +++ b/volumes.c @@ -1397,7 +1397,7 @@ again: if (rw == WRITE) multi->num_stripes = map->num_stripes; else if (mirror_num) - stripe_index = mirror_num - 1; + stripe_index = mirror_num; else stripe_index = stripe_nr % map->num_stripes; } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) { @@ -1416,7 +1416,7 @@ again: if (rw == WRITE) multi->num_stripes = map->num_stripes; else if (mirror_num) - stripe_index = mirror_num - 1; + stripe_index = mirror_num; } else if (map->type & (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6)) { -- 2.3.7 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html