Btrfs: properly check free space for tree balancing

btrfs_insert_empty_items takes the space needed by the btrfs_item
structure into account when calculating the required free space.

So the tree balancing code shouldn't add sizeof(struct btrfs_item)
to the size when checking the free space. This patch removes these
superfluous additions.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>

1 files changed, 26 insertions, 26 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index f6f7a6af0357..7fad2e3ad6ff 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1587,8 +1587,8 @@ cow_done:
                                 btrfs_tree_lock(b);
                 } else {
                         p->slots[level] = slot;
-                        if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
-                            sizeof(struct btrfs_item) + ins_len) {
+                        if (ins_len > 0 &&
+                            btrfs_leaf_free_space(root, b) < ins_len) {
                                 int sret = split_leaf(trans, root, key,
                                                       p, ins_len, ret == 0);
                                 BUG_ON(sret > 0);
@@ -2231,7 +2231,7 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
         right = read_node_slot(root, upper, slot + 1);
         btrfs_tree_lock(right);
         free_space = btrfs_leaf_free_space(root, right);
-        if (free_space < data_size + sizeof(struct btrfs_item))
+        if (free_space < data_size)
                 goto out_unlock;
 
         /* cow and double check */
@@ -2241,7 +2241,7 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
                 goto out_unlock;
 
         free_space = btrfs_leaf_free_space(root, right);
-        if (free_space < data_size + sizeof(struct btrfs_item))
+        if (free_space < data_size)
                 goto out_unlock;
 
         left_nritems = btrfs_header_nritems(left);
@@ -2254,7 +2254,7 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
                 nr = 1;
 
         if (path->slots[0] >= left_nritems)
-                push_space += data_size + sizeof(*item);
+                push_space += data_size;
 
         i = left_nritems - 1;
         while (i >= nr) {
@@ -2271,7 +2271,7 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
                 }
 
                 if (path->slots[0] == i)
-                        push_space += data_size + sizeof(*item);
+                        push_space += data_size;
 
                 if (!left->map_token) {
                         map_extent_buffer(left, (unsigned long)item,
@@ -2427,7 +2427,7 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
         left = read_node_slot(root, path->nodes[1], slot - 1);
         btrfs_tree_lock(left);
         free_space = btrfs_leaf_free_space(root, left);
-        if (free_space < data_size + sizeof(struct btrfs_item)) {
+        if (free_space < data_size) {
                 ret = 1;
                 goto out;
         }
@@ -2442,7 +2442,7 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
         }
 
         free_space = btrfs_leaf_free_space(root, left);
-        if (free_space < data_size + sizeof(struct btrfs_item)) {
+        if (free_space < data_size) {
                 ret = 1;
                 goto out;
         }
@@ -2473,7 +2473,7 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
                 }
 
                 if (path->slots[0] == i)
-                        push_space += data_size + sizeof(*item);
+                        push_space += data_size;
 
                 this_item_size = btrfs_item_size(right, item);
                 if (this_item_size + sizeof(*item) + push_space > free_space)
@@ -2510,7 +2510,7 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
                      btrfs_item_offset_nr(right, push_items - 1),
                      push_space);
         old_left_nritems = btrfs_header_nritems(left);
-        BUG_ON(old_left_nritems < 0);
+        BUG_ON(old_left_nritems <= 0);
 
         old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
         for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
@@ -2628,7 +2628,6 @@ static noinline int split_leaf(struct btrfs_trans_handle *trans,
         int mid;
         int slot;
         struct extent_buffer *right;
-        int space_needed = data_size + sizeof(struct btrfs_item);
         int data_copy_size;
         int rt_data_off;
         int i;
@@ -2638,9 +2637,6 @@ static noinline int split_leaf(struct btrfs_trans_handle *trans,
         int num_doubles = 0;
         struct btrfs_disk_key disk_key;
 
-        if (extend && data_size)
-                space_needed = data_size;
-
         /* first try to make some room by pushing left and right */
         if (data_size && ins_key->type != BTRFS_DIR_ITEM_KEY) {
                 wret = push_leaf_right(trans, root, path, data_size, 0);
@@ -2655,7 +2651,7 @@ static noinline int split_leaf(struct btrfs_trans_handle *trans,
                 l = path->nodes[0];
 
                 /* did the pushes work? */
-                if (btrfs_leaf_free_space(root, l) >= space_needed)
+                if (btrfs_leaf_free_space(root, l) >= data_size)
                         return 0;
         }
 
@@ -2694,7 +2690,7 @@ again:
                             BTRFS_UUID_SIZE);
         if (mid <= slot) {
                 if (nritems == 1 ||
-                    leaf_space_used(l, mid, nritems - mid) + space_needed >
+                    leaf_space_used(l, mid, nritems - mid) + data_size >
                         BTRFS_LEAF_DATA_SIZE(root)) {
                         if (slot >= nritems) {
                                 btrfs_cpu_key_to_disk(&disk_key, ins_key);
@@ -2716,12 +2712,12 @@ again:
                         mid = slot;
                         if (mid != nritems &&
                             leaf_space_used(l, mid, nritems - mid) +
-                            space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
+                            data_size > BTRFS_LEAF_DATA_SIZE(root)) {
                                 double_split = 1;
                         }
                 }
         } else {
-                if (leaf_space_used(l, 0, mid + 1) + space_needed >
+                if (leaf_space_used(l, 0, mid) + data_size >
                         BTRFS_LEAF_DATA_SIZE(root)) {
                         if (!extend && data_size && slot == 0) {
                                 btrfs_cpu_key_to_disk(&disk_key, ins_key);
@@ -2750,7 +2746,7 @@ again:
                                 mid = slot;
                                 if (mid != nritems &&
                                     leaf_space_used(l, mid, nritems - mid) +
-                                    space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
+                                    data_size > BTRFS_LEAF_DATA_SIZE(root)) {
                                         double_split = 1;
                                 }
                         }
@@ -2883,7 +2879,8 @@ int btrfs_split_item(struct btrfs_trans_handle *trans,
                 return -EAGAIN;
         }
 
-        ret = split_leaf(trans, root, &orig_key, path, 0, 0);
+        ret = split_leaf(trans, root, &orig_key, path,
+                         sizeof(struct btrfs_item), 1);
         path->keep_locks = 0;
         BUG_ON(ret);
 
@@ -3169,14 +3166,17 @@ int btrfs_insert_some_items(struct btrfs_trans_handle *trans,
         struct btrfs_disk_key disk_key;
         struct btrfs_key found_key;
 
-        found_key.objectid = 0;
-        nr = min_t(int, nr, BTRFS_NODEPTRS_PER_BLOCK(root));
-
-        for (i = 0; i < nr; i++)
+        for (i = 0; i < nr; i++) {
+                if (total_size + data_size[i] + sizeof(struct btrfs_item) >
+                    BTRFS_LEAF_DATA_SIZE(root)) {
+                        break;
+                        nr = i;
+                }
                 total_data += data_size[i];
+                total_size += data_size[i] + sizeof(struct btrfs_item);
+        }
+        BUG_ON(nr == 0);
 
-        total_data = min_t(u32, total_data, BTRFS_LEAF_DATA_SIZE(root));
-        total_size = total_data + (nr * sizeof(struct btrfs_item));
         ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
         if (ret == 0)
                 return -EEXIST;