The main balance function has two loops which are functionally
identical in their looping mechanism, but which perform a different
operation on the chunks they loop over. To avoid repeating code more
than necessary, factor this loop out into a separate iterator function
which takes a function parameter for the action to be performed.
Signed-off-by: Hugo Mills
---
fs/btrfs/volumes.c | 174 +--
1 files changed, 99 insertions(+), 75 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index cf019af..20c2772 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2029,6 +2029,97 @@ static u64 div_factor(u64 num, int factor)
return num;
}
+/* Define a type, and two functions which can be used for the two
+ * phases of the balance operation: one for counting chunks, and one
+ * for actually moving them. */
+typedef void (*balance_iterator_function)(struct btrfs_root *,
+ struct btrfs_balance_info *,
+ struct btrfs_path *,
+ struct btrfs_key *);
+
+static void balance_count_chunks(struct btrfs_root *chunk_root,
+ struct btrfs_balance_info *bal_info,
+ struct btrfs_path *path,
+ struct btrfs_key *key)
+{
+ spin_lock(&chunk_root->fs_info->balance_info_lock);
+ bal_info->expected++;
+ spin_unlock(&chunk_root->fs_info->balance_info_lock);
+}
+
+static void balance_move_chunks(struct btrfs_root *chunk_root,
+struct btrfs_balance_info *bal_info,
+struct btrfs_path *path,
+struct btrfs_key *key)
+{
+ int ret;
+
+ ret = btrfs_relocate_chunk(chunk_root,
+ chunk_root->root_key.objectid,
+ key->objectid,
+ key->offset);
+ BUG_ON(ret && ret != -ENOSPC);
+ spin_lock(&chunk_root->fs_info->balance_info_lock);
+ bal_info->completed++;
+ spin_unlock(&chunk_root->fs_info->balance_info_lock);
+ printk(KERN_INFO "btrfs: balance: %llu/%llu block groups completed\n",
+ bal_info->completed, bal_info->expected);
+}
+
+/* Iterate through all chunks, performing some function on each one. */
+static int balance_iterate_chunks(struct btrfs_root *chunk_root,
+ struct btrfs_balance_info *bal_info,
+ balance_iterator_function iterator_fn)
+{
+ int ret = 0;
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ struct btrfs_key found_key;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
+ key.offset = (u64)-1;
+ key.type = BTRFS_CHUNK_ITEM_KEY;
+
+ while (!bal_info->cancel_pending) {
+ ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
+ if (ret < 0)
+ break;
+ /*
+* this shouldn't happen, it means the last relocate
+* failed
+*/
+ if (ret == 0)
+ break;
+
+ ret = btrfs_previous_item(chunk_root, path, 0,
+ BTRFS_CHUNK_ITEM_KEY);
+ if (ret)
+ break;
+
+ btrfs_item_key_to_cpu(path->nodes[0], &found_key,
+ path->slots[0]);
+ if (found_key.objectid != key.objectid)
+ break;
+
+ /* chunk zero is special */
+ if (found_key.offset == 0)
+ break;
+
+ /* Call the function to do the work for this chunk */
+ btrfs_release_path(chunk_root, path);
+ iterator_fn(chunk_root, bal_info, path, &found_key);
+
+ key.offset = found_key.offset - 1;
+ }
+
+ btrfs_free_path(path);
+ return ret;
+}
+
int btrfs_balance(struct btrfs_root *dev_root)
{
int ret;
@@ -2036,11 +2127,8 @@ int btrfs_balance(struct btrfs_root *dev_root)
struct btrfs_device *device;
u64 old_size;
u64 size_to_free;
- struct btrfs_path *path;
- struct btrfs_key key;
struct btrfs_root *chunk_root = dev_root->fs_info->chunk_root;
struct btrfs_trans_handle *trans;
- struct btrfs_key found_key;
struct btrfs_balance_info *bal_info;
if (dev_root->fs_info->sb->s_flags & MS_RDONLY)
@@ -2061,8 +2149,7 @@ int btrfs_balance(struct btrfs_root *dev_root)
}
spin_lock(&dev_root->fs_info->balance_info_lock);
dev_root->fs_info->balance_info = bal_info;
- bal_info->expected = -1; /* One less than actually counted,
- because chunk
