Btrfs: Implement basic support for -ENOSPC

This is intended to prevent accidentally filling the drive.  A determined
user can still make things oops.

It includes some accounting of the current bytes under delayed allocation,
but this will change as things get optimized

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

1 files changed, 4 insertions, 1 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index ebb2db624fdd..eebb4fb65c61 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -223,7 +223,8 @@ static int btree_writepages(struct address_space *mapping,
                 } else {
                         thresh = 8 * 1024 * 1024;
                 }
-                num_dirty = count_range_bits(tree, &start, thresh, EXTENT_DIRTY);
+                num_dirty = count_range_bits(tree, &start, (u64)-1,
+                                             thresh, EXTENT_DIRTY);
                 if (num_dirty < thresh) {
                         return 0;
                 }
@@ -559,6 +560,7 @@ struct btrfs_root *open_ctree(struct super_block *sb)
         INIT_LIST_HEAD(&fs_info->dead_roots);
         INIT_LIST_HEAD(&fs_info->hashers);
         spin_lock_init(&fs_info->hash_lock);
+        spin_lock_init(&fs_info->delalloc_lock);
 
         memset(&fs_info->super_kobj, 0, sizeof(fs_info->super_kobj));
         init_completion(&fs_info->kobj_unregister);
@@ -570,6 +572,7 @@ struct btrfs_root *open_ctree(struct super_block *sb)
         fs_info->sb = sb;
         fs_info->mount_opt = 0;
         fs_info->max_extent = (u64)-1;
+        fs_info->delalloc_bytes = 0;
         fs_info->btree_inode = new_inode(sb);
         fs_info->btree_inode->i_ino = 1;
         fs_info->btree_inode->i_nlink = 1;