Btrfs: Find and remove dead roots the first time a root is loaded.
Dead roots are trees left over after a crash, and they were either in the
process of being removed or were waiting to be removed when the box crashed.
Before, a search of the entire tree of root pointers was done on mount
looking for dead roots. Now, the search is done the first time we load
a root.
This makes mount faster when there are a large number of snapshots, and it
enables the block accounting code to properly update the block counts on
the latest root as old versions of the root are reaped after a crash.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index 402f678..3b5926d 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -93,7 +93,8 @@
return ret;
}
-int btrfs_find_dead_roots(struct btrfs_root *root)
+int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid,
+ struct btrfs_root *latest)
{
struct btrfs_root *dead_root;
struct btrfs_item *item;
@@ -105,7 +106,7 @@
struct btrfs_leaf *leaf;
int slot;
- key.objectid = 0;
+ key.objectid = objectid;
key.flags = 0;
btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
key.offset = 0;
@@ -131,15 +132,24 @@
btrfs_disk_key_to_cpu(&key, &item->key);
if (btrfs_key_type(&key) != BTRFS_ROOT_ITEM_KEY)
goto next;
+
+ if (key.objectid < objectid)
+ goto next;
+
+ if (key.objectid > objectid)
+ break;
+
ri = btrfs_item_ptr(leaf, slot, struct btrfs_root_item);
if (btrfs_root_refs(ri) != 0)
goto next;
+
dead_root = btrfs_read_fs_root_no_radix(root->fs_info, &key);
if (IS_ERR(dead_root)) {
ret = PTR_ERR(dead_root);
goto err;
}
- ret = btrfs_add_dead_root(dead_root,
+
+ ret = btrfs_add_dead_root(dead_root, latest,
&root->fs_info->dead_roots);
if (ret)
goto err;