Btrfs: write barriers on commit, balance level before split

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

3 files changed, 131 insertions, 1 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 4efcd1bd63e5..744fd728e5d9 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -151,6 +151,11 @@ static int check_node(struct btrfs_root *root, struct btrfs_path *path,
         for (i = 0; nritems > 1 && i < nritems - 2; i++) {
                 struct btrfs_key cpukey;
                 btrfs_disk_key_to_cpu(&cpukey, &node->ptrs[i + 1].key);
+if (comp_keys(&node->ptrs[i].key, &cpukey) >= 0) {
+        struct btrfs_key bad;
+        btrfs_disk_key_to_cpu(&bad, &node->ptrs[i].key);
+printk("check_node level %d i is %d bad comp %Lu %u %Lu, %Lu %u %Lu\n",level, i, bad.objectid, bad.flags, bad.offset, cpukey.objectid, cpukey.flags, cpukey.offset);
+}
                 BUG_ON(comp_keys(&node->ptrs[i].key, &cpukey) >= 0);
         }
         return 0;
@@ -448,6 +453,111 @@ static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
         return ret;
 }
 
+/* returns zero if the push worked, non-zero otherwise */
+static int push_nodes_for_insert(struct btrfs_trans_handle *trans,
+                                struct btrfs_root *root,
+                                struct btrfs_path *path, int level)
+{
+        struct buffer_head *right_buf;
+        struct buffer_head *mid_buf;
+        struct buffer_head *left_buf;
+        struct buffer_head *parent_buf = NULL;
+        struct btrfs_node *right = NULL;
+        struct btrfs_node *mid;
+        struct btrfs_node *left = NULL;
+        struct btrfs_node *parent = NULL;
+        int ret = 0;
+        int wret;
+        int pslot;
+        int orig_slot = path->slots[level];
+        u64 orig_ptr;
+
+        if (level == 0)
+                return 1;
+
+        mid_buf = path->nodes[level];
+        mid = btrfs_buffer_node(mid_buf);
+        orig_ptr = btrfs_node_blockptr(mid, orig_slot);
+
+        if (level < BTRFS_MAX_LEVEL - 1)
+                parent_buf = path->nodes[level + 1];
+        pslot = path->slots[level + 1];
+
+        if (!parent_buf)
+                return 1;
+        parent = btrfs_buffer_node(parent_buf);
+
+        left_buf = read_node_slot(root, parent_buf, pslot - 1);
+
+        /* first, try to make some room in the middle buffer */
+        if (left_buf) {
+                u32 left_nr;
+                btrfs_cow_block(trans, root, left_buf, parent_buf, pslot - 1,
+                                &left_buf);
+                left = btrfs_buffer_node(left_buf);
+                left_nr = btrfs_header_nritems(&left->header);
+                wret = push_node_left(trans, root, left_buf, mid_buf);
+                if (wret < 0)
+                        ret = wret;
+                if (wret == 0) {
+                        orig_slot += left_nr;
+                        btrfs_memcpy(root, parent,
+                                     &parent->ptrs[pslot].key,
+                                     &mid->ptrs[0].key,
+                                     sizeof(struct btrfs_disk_key));
+                        btrfs_mark_buffer_dirty(parent_buf);
+                        if (btrfs_header_nritems(&left->header) > orig_slot) {
+                                path->nodes[level] = left_buf;
+                                path->slots[level + 1] -= 1;
+                                path->slots[level] = orig_slot;
+                                btrfs_block_release(root, mid_buf);
+                        } else {
+                                orig_slot -=
+                                        btrfs_header_nritems(&left->header);
+                                path->slots[level] = orig_slot;
+                                btrfs_block_release(root, left_buf);
+                        }
+                        check_node(root, path, level);
+                        return 0;
+                }
+                btrfs_block_release(root, left_buf);
+        }
+        right_buf = read_node_slot(root, parent_buf, pslot + 1);
+
+        /*
+         * then try to empty the right most buffer into the middle
+         */
+        if (right_buf) {
+                btrfs_cow_block(trans, root, right_buf, parent_buf, pslot + 1,
+                                &right_buf);
+                right = btrfs_buffer_node(right_buf);
+                wret = balance_node_right(trans, root, right_buf, mid_buf);
+                if (wret < 0)
+                        ret = wret;
+                if (wret == 0) {
+                        btrfs_memcpy(root, parent,
+                                     &parent->ptrs[pslot + 1].key,
+                                     &right->ptrs[0].key,
+                                     sizeof(struct btrfs_disk_key));
+                        btrfs_mark_buffer_dirty(parent_buf);
+                        if (btrfs_header_nritems(&mid->header) <= orig_slot) {
+                                path->nodes[level] = right_buf;
+                                path->slots[level + 1] += 1;
+                                path->slots[level] = orig_slot -
+                                        btrfs_header_nritems(&mid->header);
+                                btrfs_block_release(root, mid_buf);
+                        } else {
+                                btrfs_block_release(root, right_buf);
+                        }
+                        check_node(root, path, level);
+                        return 0;
+                }
+                btrfs_block_release(root, right_buf);
+        }
+        check_node(root, path, level);
+        return 1;
+}
+
 /*
  * look for key in the tree.  path is filled in with nodes along the way
  * if key is found, we return zero and you can find the item in the leaf
@@ -774,7 +884,16 @@ static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
                 ret = insert_new_root(trans, root, path, level + 1);
                 if (ret)
                         return ret;
+        } else {
+                ret = push_nodes_for_insert(trans, root, path, level);
+                t = path->nodes[level];
+                c = btrfs_buffer_node(t);
+                if (!ret &&
+                    btrfs_header_nritems(&c->header) <
+                    BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
+                        return 0;
         }
+
         c_nritems = btrfs_header_nritems(&c->header);
         split_buffer = btrfs_alloc_free_block(trans, root);
         split = btrfs_buffer_node(split_buffer);
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 047a84762d93..681b23933d9b 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -259,6 +259,7 @@ struct btrfs_fs_info {
         struct list_head trans_list;
         struct crypto_hash *hash_tfm;
         spinlock_t hash_lock;
+        int do_barriers;
         struct kobject kobj;
 };
 
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index b666c3571aee..13046295bf7a 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -540,6 +540,7 @@ struct btrfs_root *open_ctree(struct super_block *sb)
         fs_info->btree_inode->i_nlink = 1;
         fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
+        fs_info->do_barriers = 1;
         BTRFS_I(fs_info->btree_inode)->root = tree_root;
         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
                sizeof(struct btrfs_key));
@@ -622,6 +623,7 @@ struct btrfs_root *open_ctree(struct super_block *sb)
 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
                       *root)
 {
+        int ret;
         struct buffer_head *bh = root->fs_info->sb_buffer;
 
         btrfs_set_super_root(root->fs_info->disk_super,
@@ -632,7 +634,15 @@ int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
         csum_tree_block(root, bh, 0);
         bh->b_end_io = end_buffer_write_sync;
         get_bh(bh);
-        submit_bh(WRITE, bh);
+        if (root->fs_info->do_barriers)
+                ret = submit_bh(WRITE_BARRIER, bh);
+        else
+                ret = submit_bh(WRITE, bh);
+        if (ret == -EOPNOTSUPP) {
+                set_buffer_uptodate(bh);
+                root->fs_info->do_barriers = 0;
+                ret = submit_bh(WRITE, bh);
+        }
         wait_on_buffer(bh);
         if (!buffer_uptodate(bh)) {
                 WARN_ON(1);