Btrfs: try to keep a healthy ratio of metadata vs data block groups

[linux-2.6-block.git] / fs / btrfs / extent-tree.c

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 178df4c67de447e87514e90284a7ccc294dc8df1..2895a8373232743c599c51c3c25ba9187162445e 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1918,15 +1918,29 @@ void btrfs_delalloc_free_space(struct btrfs_root *root, struct inode *inode,
        spin_unlock(&info->lock);
 }
 
+static void force_metadata_allocation(struct btrfs_fs_info *info)
+{
+       struct list_head *head = &info->space_info;
+       struct btrfs_space_info *found;
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(found, head, list) {
+               if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
+                       found->force_alloc = 1;
+       }
+       rcu_read_unlock();
+}
+
 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
                          struct btrfs_root *extent_root, u64 alloc_bytes,
                          u64 flags, int force)
 {
        struct btrfs_space_info *space_info;
+       struct btrfs_fs_info *fs_info = extent_root->fs_info;
        u64 thresh;
        int ret = 0;
 
-       mutex_lock(&extent_root->fs_info->chunk_mutex);
+       mutex_lock(&fs_info->chunk_mutex);
 
        flags = btrfs_reduce_alloc_profile(extent_root, flags);
 
@@ -1958,6 +1972,18 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans,
        }
        spin_unlock(&space_info->lock);
 
+       /*
+        * if we're doing a data chunk, go ahead and make sure that
+        * we keep a reasonable number of metadata chunks allocated in the
+        * FS as well.
+        */
+       if (flags & BTRFS_BLOCK_GROUP_DATA) {
+               fs_info->data_chunk_allocations++;
+               if (!(fs_info->data_chunk_allocations %
+                     fs_info->metadata_ratio))
+                       force_metadata_allocation(fs_info);
+       }
+
        ret = btrfs_alloc_chunk(trans, extent_root, flags);
        if (ret)
                space_info->full = 1;