Btrfs: add snapshot/subvolume destroy ioctl
This patch adds snapshot/subvolume destroy ioctl. A subvolume that isn't being
used and doesn't contains links to other subvolumes can be destroyed.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 3be16cc..48a5042 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -3203,6 +3203,7 @@
return 0;
}
+
static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
{
struct rb_root blocks = RB_ROOT;
@@ -3220,6 +3221,9 @@
if (!path)
return -ENOMEM;
+ rc->extents_found = 0;
+ rc->extents_skipped = 0;
+
rc->search_start = rc->block_group->key.objectid;
clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
GFP_NOFS);
@@ -3475,14 +3479,15 @@
btrfs_wait_ordered_extents(fs_info->tree_root, 0);
while (1) {
- mutex_lock(&fs_info->cleaner_mutex);
- btrfs_clean_old_snapshots(fs_info->tree_root);
- mutex_unlock(&fs_info->cleaner_mutex);
-
rc->extents_found = 0;
rc->extents_skipped = 0;
+ mutex_lock(&fs_info->cleaner_mutex);
+
+ btrfs_clean_old_snapshots(fs_info->tree_root);
ret = relocate_block_group(rc);
+
+ mutex_unlock(&fs_info->cleaner_mutex);
if (ret < 0) {
err = ret;
break;
@@ -3530,6 +3535,26 @@
return err;
}
+static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
+{
+ struct btrfs_trans_handle *trans;
+ int ret;
+
+ trans = btrfs_start_transaction(root->fs_info->tree_root, 1);
+
+ memset(&root->root_item.drop_progress, 0,
+ sizeof(root->root_item.drop_progress));
+ root->root_item.drop_level = 0;
+ btrfs_set_root_refs(&root->root_item, 0);
+ ret = btrfs_update_root(trans, root->fs_info->tree_root,
+ &root->root_key, &root->root_item);
+ BUG_ON(ret);
+
+ ret = btrfs_end_transaction(trans, root->fs_info->tree_root);
+ BUG_ON(ret);
+ return 0;
+}
+
/*
* recover relocation interrupted by system crash.
*
@@ -3589,8 +3614,12 @@
fs_root = read_fs_root(root->fs_info,
reloc_root->root_key.offset);
if (IS_ERR(fs_root)) {
- err = PTR_ERR(fs_root);
- goto out;
+ ret = PTR_ERR(fs_root);
+ if (ret != -ENOENT) {
+ err = ret;
+ goto out;
+ }
+ mark_garbage_root(reloc_root);
}
}