1 files changed, 27 insertions, 6 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index a872b48be0ae..1411b99555a4 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3324,12 +3324,14 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
         stripe_size = devices_info[ndevs-1].max_avail;
         num_stripes = ndevs * dev_stripes;
 
-        if (stripe_size * num_stripes > max_chunk_size * ncopies) {
+        if (stripe_size * ndevs > max_chunk_size * ncopies) {
                 stripe_size = max_chunk_size * ncopies;
-                do_div(stripe_size, num_stripes);
+                do_div(stripe_size, ndevs);
         }
 
         do_div(stripe_size, dev_stripes);
+
+        /* align to BTRFS_STRIPE_LEN */
         do_div(stripe_size, BTRFS_STRIPE_LEN);
         stripe_size *= BTRFS_STRIPE_LEN;
 
@@ -3805,10 +3807,11 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
                 else if (mirror_num)
                         stripe_index += mirror_num - 1;
                 else {
+                        int old_stripe_index = stripe_index;
                         stripe_index = find_live_mirror(map, stripe_index,
                                               map->sub_stripes, stripe_index +
                                               current->pid % map->sub_stripes);
-                        mirror_num = stripe_index + 1;
+                        mirror_num = stripe_index - old_stripe_index + 1;
                 }
         } else {
                 /*
@@ -3833,6 +3836,7 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
                 int sub_stripes = 0;
                 u64 stripes_per_dev = 0;
                 u32 remaining_stripes = 0;
+                u32 last_stripe = 0;
 
                 if (map->type &
                     (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
@@ -3846,6 +3850,8 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
                                                       stripe_nr_orig,
                                                       factor,
                                                       &remaining_stripes);
+                        div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
+                        last_stripe *= sub_stripes;
                 }
 
                 for (i = 0; i < num_stripes; i++) {
@@ -3858,16 +3864,29 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
                                          BTRFS_BLOCK_GROUP_RAID10)) {
                                 bbio->stripes[i].length = stripes_per_dev *
                                                           map->stripe_len;
+
                                 if (i / sub_stripes < remaining_stripes)
                                         bbio->stripes[i].length +=
                                                 map->stripe_len;
+
+                                /*
+                                 * Special for the first stripe and
+                                 * the last stripe:
+                                 *
+                                 * |-------|...|-------|
+                                 *     |----------|
+                                 *    off     end_off
+                                 */
                                 if (i < sub_stripes)
                                         bbio->stripes[i].length -=
                                                 stripe_offset;
-                                if ((i / sub_stripes + 1) %
-                                    sub_stripes == remaining_stripes)
+
+                                if (stripe_index >= last_stripe &&
+                                    stripe_index <= (last_stripe +
+                                                     sub_stripes - 1))
                                         bbio->stripes[i].length -=
                                                 stripe_end_offset;
+
                                 if (i == sub_stripes - 1)
                                         stripe_offset = 0;
                         } else
@@ -4334,8 +4353,10 @@ static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
 
         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
                                    root->fs_info->bdev_holder);
-        if (ret)
+        if (ret) {
+                free_fs_devices(fs_devices);
                 goto out;
+        }
 
         if (!fs_devices->seeding) {
                 __btrfs_close_devices(fs_devices);