Btrfs: Add the ability to find and remove dead roots after a crash.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 321f885..85a2a5e 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -85,11 +85,15 @@
if (root != root->fs_info->tree_root && root->last_trans <
running_trans_id) {
- radix_tree_tag_set(&root->fs_info->fs_roots_radix,
- (unsigned long)root->root_key.objectid,
- BTRFS_ROOT_TRANS_TAG);
- root->commit_root = root->node;
- get_bh(root->node);
+ if (root->root_item.refs != 0) {
+ radix_tree_tag_set(&root->fs_info->fs_roots_radix,
+ (unsigned long)root->root_key.objectid,
+ BTRFS_ROOT_TRANS_TAG);
+ root->commit_root = root->node;
+ get_bh(root->node);
+ } else {
+ WARN_ON(1);
+ }
}
root->last_trans = running_trans_id;
h->transid = running_trans_id;
@@ -208,8 +212,24 @@
struct btrfs_key snap_key;
struct buffer_head *commit_root;
struct btrfs_root *root;
+ int free_on_drop;
};
+int btrfs_add_dead_root(struct btrfs_root *root, struct list_head *dead_list)
+{
+ struct dirty_root *dirty;
+
+ dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
+ if (!dirty)
+ return -ENOMEM;
+ memcpy(&dirty->snap_key, &root->root_key, sizeof(root->root_key));
+ dirty->commit_root = root->node;
+ dirty->root = root;
+ dirty->free_on_drop = 1;
+ list_add(&dirty->list, dead_list);
+ return 0;
+}
+
static int add_dirty_roots(struct btrfs_trans_handle *trans,
struct radix_tree_root *radix,
struct list_head *list)
@@ -217,9 +237,11 @@
struct dirty_root *dirty;
struct btrfs_root *gang[8];
struct btrfs_root *root;
+ struct btrfs_root_item tmp_item;
int i;
int ret;
int err = 0;
+ u32 refs;
while(1) {
ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
@@ -246,6 +268,9 @@
dirty->commit_root = root->commit_root;
root->commit_root = NULL;
dirty->root = root;
+ dirty->free_on_drop = 0;
+ memcpy(&tmp_item, &root->root_item, sizeof(tmp_item));
+
root->root_key.offset = root->fs_info->generation;
btrfs_set_root_blocknr(&root->root_item,
bh_blocknr(root->node));
@@ -254,7 +279,18 @@
&root->root_item);
if (err)
break;
- list_add(&dirty->list, list);
+
+ refs = btrfs_root_refs(&tmp_item);
+ btrfs_set_root_refs(&tmp_item, refs - 1);
+ err = btrfs_update_root(trans, root->fs_info->tree_root,
+ &dirty->snap_key,
+ &tmp_item);
+
+ BUG_ON(err);
+ if (refs == 1)
+ list_add(&dirty->list, list);
+ else
+ kfree(dirty);
}
}
return err;
@@ -270,16 +306,20 @@
mutex_lock(&tree_root->fs_info->fs_mutex);
dirty = list_entry(list->next, struct dirty_root, list);
list_del_init(&dirty->list);
+
trans = btrfs_start_transaction(tree_root, 1);
+printk("deleting root %Lu %u %Lu\n", dirty->snap_key.objectid, dirty->snap_key.flags, dirty->snap_key.offset);
ret = btrfs_drop_snapshot(trans, dirty->root,
dirty->commit_root);
BUG_ON(ret);
-
ret = btrfs_del_root(trans, tree_root, &dirty->snap_key);
if (ret)
break;
ret = btrfs_end_transaction(trans, tree_root);
BUG_ON(ret);
+
+ if (dirty->free_on_drop)
+ kfree(dirty->root);
kfree(dirty);
mutex_unlock(&tree_root->fs_info->fs_mutex);
btrfs_btree_balance_dirty(tree_root);