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/ctree.h b/fs/btrfs/ctree.h
index 03e1c4a..6d6e94b 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1148,7 +1148,8 @@
*item);
int btrfs_find_last_root(struct btrfs_root *root, u64 objectid, struct
btrfs_root_item *item, struct btrfs_key *key);
-int btrfs_find_dead_roots(struct btrfs_root *root);
+int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid,
+ struct btrfs_root *latest_root);
/* dir-item.c */
int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
*root, const char *name, int name_len, u64 dir,
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 6c953a0..4296839 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -426,6 +426,10 @@
return ERR_PTR(ret);
}
+ ret = btrfs_find_dead_roots(fs_info->tree_root,
+ root->root_key.objectid, root);
+ BUG_ON(ret);
+
return root;
}
@@ -522,11 +526,6 @@
btrfs_read_block_groups(extent_root);
fs_info->generation = btrfs_super_generation(disk_super) + 1;
- ret = btrfs_find_dead_roots(tree_root);
- if (ret) {
- mutex_unlock(&fs_info->fs_mutex);
- goto fail_tree_root;
- }
mutex_unlock(&fs_info->fs_mutex);
return tree_root;
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;
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 2b15daa..2975559 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -239,7 +239,9 @@
struct btrfs_root *latest_root;
};
-int btrfs_add_dead_root(struct btrfs_root *root, struct list_head *dead_list)
+int btrfs_add_dead_root(struct btrfs_root *root,
+ struct btrfs_root *latest,
+ struct list_head *dead_list)
{
struct dirty_root *dirty;
@@ -247,6 +249,7 @@
if (!dirty)
return -ENOMEM;
dirty->root = root;
+ dirty->latest_root = latest;
list_add(&dirty->list, dead_list);
return 0;
}
@@ -412,7 +415,6 @@
while(1) {
trans = btrfs_start_transaction(tree_root, 1);
-
ret = btrfs_drop_snapshot(trans, dirty->root);
if (ret != -EAGAIN) {
break;
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index e451783..4bc328c 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -78,7 +78,8 @@
void btrfs_transaction_queue_work(struct btrfs_root *root, int delay);
void btrfs_init_transaction_sys(void);
void btrfs_exit_transaction_sys(void);
-int btrfs_add_dead_root(struct btrfs_root *root, struct list_head *dead_list);
+int btrfs_add_dead_root(struct btrfs_root *root, struct btrfs_root *latest,
+ struct list_head *dead_list);
int btrfs_defrag_dirty_roots(struct btrfs_fs_info *info);
int btrfs_defrag_root(struct btrfs_root *root, int cacheonly);
int btrfs_clean_old_snapshots(struct btrfs_root *root);