Btrfs: Change push_leaf_{leaf,right} to empty the src leave during item deletion

Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index ea9b4669934993bc4a42787355fdd82e5e976cda..1b47fe71e0b410b1efa8ae03c9e94b484c769761 100644 (file)
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1394,19 +1394,21 @@ int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
  * room, 0 if everything worked out and < 0 if there were major errors.
  */
 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
-                          *root, struct btrfs_path *path, int data_size)
+                          *root, struct btrfs_path *path, int data_size,
+                          int empty)
 {
        struct extent_buffer *left = path->nodes[0];
        struct extent_buffer *right;
        struct extent_buffer *upper;
        struct btrfs_disk_key disk_key;
        int slot;
-       int i;
+       u32 i;
        int free_space;
        int push_space = 0;
        int push_items = 0;
        struct btrfs_item *item;
        u32 left_nritems;
+       u32 nr;
        u32 right_nritems;
        u32 data_end;
        u32 this_item_size;
@@ -1447,7 +1449,13 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
                return 1;
        }
 
-       for (i = left_nritems - 1; i >= 1; i--) {
+       if (empty)
+               nr = 0;
+       else
+               nr = 1;
+
+       i = left_nritems - 1;
+       while (i >= nr) {
                item = btrfs_item_nr(left, i);
 
                if (path->slots[0] == i)
@@ -1466,6 +1474,9 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
                        break;
                push_items++;
                push_space += this_item_size + sizeof(*item);
+               if (i == 0)
+                       break;
+               i--;
        }
        if (left->map_token) {
                unmap_extent_buffer(left, left->map_token, KM_USER1);
@@ -1477,11 +1488,12 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
                return 1;
        }
 
-       if (push_items == left_nritems)
+       if (!empty && push_items == left_nritems)
                WARN_ON(1);
 
        /* push left to right */
        right_nritems = btrfs_header_nritems(right);
+
        push_space = btrfs_item_end_nr(left, left_nritems - push_items);
        push_space -= leaf_data_end(root, left);
 
@@ -1511,7 +1523,6 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
        right_nritems += push_items;
        btrfs_set_header_nritems(right, right_nritems);
        push_space = BTRFS_LEAF_DATA_SIZE(root);
-
        for (i = 0; i < right_nritems; i++) {
                item = btrfs_item_nr(right, i);
                if (!right->map_token) {
@@ -1532,7 +1543,8 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
        left_nritems -= push_items;
        btrfs_set_header_nritems(left, left_nritems);
 
-       btrfs_mark_buffer_dirty(left);
+       if (left_nritems)
+               btrfs_mark_buffer_dirty(left);
        btrfs_mark_buffer_dirty(right);
 
        btrfs_item_key(right, &disk_key, 0);
@@ -1555,7 +1567,8 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
  */
 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
-                         *root, struct btrfs_path *path, int data_size)
+                         *root, struct btrfs_path *path, int data_size,
+                         int empty)
 {
        struct btrfs_disk_key disk_key;
        struct extent_buffer *right = path->nodes[0];
@@ -1568,6 +1581,7 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
        struct btrfs_item *item;
        u32 old_left_nritems;
        u32 right_nritems;
+       u32 nr;
        int ret = 0;
        int wret;
        u32 this_item_size;
@@ -1607,7 +1621,12 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
                return 1;
        }
 
-       for (i = 0; i < right_nritems - 1; i++) {
+       if (empty)
+               nr = right_nritems;
+       else
+               nr = right_nritems - 1;
+
+       for (i = 0; i < nr; i++) {
                item = btrfs_item_nr(right, i);
                if (!right->map_token) {
                        map_extent_buffer(right, (unsigned long)item,
@@ -1637,7 +1656,7 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
                free_extent_buffer(left);
                return 1;
        }
-       if (push_items == btrfs_header_nritems(right))
+       if (!empty && push_items == btrfs_header_nritems(right))
                WARN_ON(1);
 
        /* push data from right to left */
@@ -1681,20 +1700,26 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
        }
 
        /* fixup right node */
-       push_space = btrfs_item_offset_nr(right, push_items - 1) -
-                                         leaf_data_end(root, right);
-       memmove_extent_buffer(right, btrfs_leaf_data(right) +
-                             BTRFS_LEAF_DATA_SIZE(root) - push_space,
-                             btrfs_leaf_data(right) +
-                             leaf_data_end(root, right), push_space);
-
-       memmove_extent_buffer(right, btrfs_item_nr_offset(0),
+       if (push_items > right_nritems) {
+               printk("push items %d nr %u\n", push_items, right_nritems);
+               WARN_ON(1);
+       }
+
+       if (push_items < right_nritems) {
+               push_space = btrfs_item_offset_nr(right, push_items - 1) -
+                                                 leaf_data_end(root, right);
+               memmove_extent_buffer(right, btrfs_leaf_data(right) +
+                                     BTRFS_LEAF_DATA_SIZE(root) - push_space,
+                                     btrfs_leaf_data(right) +
+                                     leaf_data_end(root, right), push_space);
+
+               memmove_extent_buffer(right, btrfs_item_nr_offset(0),
                              btrfs_item_nr_offset(push_items),
                             (btrfs_header_nritems(right) - push_items) *
                             sizeof(struct btrfs_item));
 
-       right_nritems = btrfs_header_nritems(right) - push_items;
-       btrfs_set_header_nritems(right, right_nritems);
+       }
+       btrfs_set_header_nritems(right, right_nritems - push_items);
        push_space = BTRFS_LEAF_DATA_SIZE(root);
 
        for (i = 0; i < right_nritems; i++) {
@@ -1717,7 +1742,8 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
        }
 
        btrfs_mark_buffer_dirty(left);
-       btrfs_mark_buffer_dirty(right);
+       if (right_nritems)
+               btrfs_mark_buffer_dirty(right);
 
        btrfs_item_key(right, &disk_key, 0);
        wret = fixup_low_keys(trans, root, path, &disk_key, 1);
@@ -1768,12 +1794,12 @@ static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
 
        /* first try to make some room by pushing left and right */
        if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
-               wret = push_leaf_right(trans, root, path, data_size);
+               wret = push_leaf_right(trans, root, path, data_size, 0);
                if (wret < 0) {
                        return wret;
                }
                if (wret) {
-                       wret = push_leaf_left(trans, root, path, data_size);
+                       wret = push_leaf_left(trans, root, path, data_size, 0);
                        if (wret < 0)
                                return wret;
                }
@@ -2403,13 +2429,13 @@ int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                        slot = path->slots[1];
                        extent_buffer_get(leaf);
 
-                       wret = push_leaf_right(trans, root, path, 1);
+                       wret = push_leaf_right(trans, root, path, 1, 1);
                        if (wret < 0 && wret != -ENOSPC)
                                ret = wret;
 
                        if (path->nodes[0] == leaf &&
                            btrfs_header_nritems(leaf)) {
-                               wret = push_leaf_left(trans, root, path, 1);
+                               wret = push_leaf_left(trans, root, path, 1, 1);
                                if (wret < 0 && wret != -ENOSPC)
                                        ret = wret;
                        }