Btrfs: Fix for lockdep warnings with alloc_mutex and pinned_mutex

This the lockdep complaint by having a different mutex to gaurd caching the
block group, so you don't end up with this backwards dependancy.  Thank you,

Signed-off-by: Josef Bacik <jbacik@redhat.com>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 0f2a9b5..166896d 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -580,6 +580,7 @@ struct btrfs_block_group_cache {
        struct btrfs_block_group_item item;
        spinlock_t lock;
        struct mutex alloc_mutex;
+       struct mutex cache_mutex;
        u64 pinned;
        u64 reserved;
        u64 flags;

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index b33e0bf..a970472 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -170,8 +170,8 @@ static int add_new_free_space(struct btrfs_block_group_cache *block_group,
                        start = extent_end + 1;
                } else if (extent_start > start && extent_start < end) {
                        size = extent_start - start;
-                       ret = btrfs_add_free_space_lock(block_group, start,
-                                                       size);
+                       ret = btrfs_add_free_space(block_group, start,
+                                                  size);
                        BUG_ON(ret);
                        start = extent_end + 1;
                } else {
@@ -181,7 +181,7 @@ static int add_new_free_space(struct btrfs_block_group_cache *block_group,
 
        if (start < end) {
                size = end - start;
-               ret = btrfs_add_free_space_lock(block_group, start, size);
+               ret = btrfs_add_free_space(block_group, start, size);
                BUG_ON(ret);
        }
        mutex_unlock(&info->pinned_mutex);
@@ -2842,17 +2842,19 @@ static int noinline find_free_extent(struct btrfs_trans_handle *trans,
                if (!block_group)
                        goto new_group_no_lock;
 
+               if (unlikely(!block_group->cached)) {
+                       mutex_lock(&block_group->cache_mutex);
+                       ret = cache_block_group(root, block_group);
+                       mutex_unlock(&block_group->cache_mutex);
+                       if (ret)
+                               break;
+               }
+
                mutex_lock(&block_group->alloc_mutex);
                if (unlikely(!block_group_bits(block_group, data)))
                        goto new_group;
 
-               ret = cache_block_group(root, block_group);
-               if (ret) {
-                       mutex_unlock(&block_group->alloc_mutex);
-                       break;
-               }
-
-               if (block_group->ro)
+               if (unlikely(block_group->ro))
                        goto new_group;
 
                free_space = btrfs_find_free_space(block_group, search_start,
@@ -3273,12 +3275,12 @@ int btrfs_alloc_logged_extent(struct btrfs_trans_handle *trans,
        struct btrfs_block_group_cache *block_group;
 
        block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
-       mutex_lock(&block_group->alloc_mutex);
+       mutex_lock(&block_group->cache_mutex);
        cache_block_group(root, block_group);
+       mutex_unlock(&block_group->cache_mutex);
 
-       ret = btrfs_remove_free_space_lock(block_group, ins->objectid,
-                                          ins->offset);
-       mutex_unlock(&block_group->alloc_mutex);
+       ret = btrfs_remove_free_space(block_group, ins->objectid,
+                                     ins->offset);
        BUG_ON(ret);
        ret = __btrfs_alloc_reserved_extent(trans, root, parent, root_objectid,
                                            ref_generation, owner, ins);
@@ -5801,6 +5803,7 @@ int btrfs_read_block_groups(struct btrfs_root *root)
 
                spin_lock_init(&cache->lock);
                mutex_init(&cache->alloc_mutex);
+               mutex_init(&cache->cache_mutex);
                INIT_LIST_HEAD(&cache->list);
                read_extent_buffer(leaf, &cache->item,
                                   btrfs_item_ptr_offset(leaf, path->slots[0]),
@@ -5854,6 +5857,7 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans,
        cache->key.offset = size;
        spin_lock_init(&cache->lock);
        mutex_init(&cache->alloc_mutex);
+       mutex_init(&cache->cache_mutex);
        INIT_LIST_HEAD(&cache->list);
        btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);