Btrfs: very minimal locking

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

4 files changed, 22 insertions, 11 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 96cec6352f12..68cafae6a850 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -231,6 +231,7 @@ struct btrfs_fs_info {
         struct buffer_head *sb_buffer;
         struct super_block *sb;
         struct mutex trans_mutex;
+        struct mutex fs_mutex;
 };
 
 /*
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 3dea757d4cbb..e32ddff55b0e 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -116,6 +116,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         fs_info->sb_buffer = sb_buffer;
         fs_info->sb = sb;
         mutex_init(&fs_info->trans_mutex);
+        mutex_init(&fs_info->fs_mutex);
         memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
         memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));
 
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index c86f0e6152f2..9583a9ae8b79 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -168,9 +168,10 @@ static int pin_down_block(struct btrfs_root *root, u64 blocknr, int tag)
         BUG_ON(!bh);
         err = radix_tree_insert(&root->fs_info->pinned_radix,
                                 blocknr, bh);
-        BUG_ON(err);
-        if (err)
+        if (err && err != -EEXIST) {
+                BUG();
                 return err;
+        }
         radix_tree_tag_set(&root->fs_info->pinned_radix, blocknr,
                            tag);
         return 0;
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index a2db05594695..0ca1080e0198 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -453,25 +453,21 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry,
         struct inode *inode;
         int err;
 
+        mutex_lock(&root->fs_info->fs_mutex);
         trans = btrfs_start_transaction(root, 1);
         inode = btrfs_new_inode(trans, dir, mode);
         err = PTR_ERR(inode);
         if (IS_ERR(inode))
-                return err;
+                goto out_unlock;
         // FIXME mark the inode dirty
         err = btrfs_add_nondir(trans, dentry, inode);
         dir->i_sb->s_dirt = 1;
         btrfs_end_transaction(trans, root);
+out_unlock:
+        mutex_unlock(&root->fs_info->fs_mutex);
         return err;
 }
 
-static void btrfs_write_super(struct super_block *sb)
-{
-        sb->s_dirt = 0;
-printk("btrfs write_super!\n");
-        filemap_flush(sb->s_bdev->bd_inode->i_mapping);
-}
-
 static int btrfs_sync_fs(struct super_block *sb, int wait)
 {
         struct btrfs_trans_handle *trans;
@@ -479,17 +475,29 @@ static int btrfs_sync_fs(struct super_block *sb, int wait)
         int ret;
 
         sb->s_dirt = 0;
-        return 0;
+        if (!wait) {
+                filemap_flush(sb->s_bdev->bd_inode->i_mapping);
+                return 0;
+        }
+        filemap_write_and_wait(sb->s_bdev->bd_inode->i_mapping);
 
         root = btrfs_sb(sb);
+        mutex_lock(&root->fs_info->fs_mutex);
         trans = btrfs_start_transaction(root, 1);
         ret = btrfs_commit_transaction(trans, root);
         sb->s_dirt = 0;
         BUG_ON(ret);
 printk("btrfs sync_fs\n");
+        mutex_unlock(&root->fs_info->fs_mutex);
         return 0;
 }
 
+static void btrfs_write_super(struct super_block *sb)
+{
+        btrfs_sync_fs(sb, 1);
+}
+
+
 static int btrfs_get_sb(struct file_system_type *fs_type,
         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 {