1 files changed, 47 insertions, 3 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index d5455a2bf60b..9a325e465ad9 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -421,7 +421,9 @@ err:
         return 0;
 }
 
-static int cache_block_group(struct btrfs_block_group_cache *cache)
+static int cache_block_group(struct btrfs_block_group_cache *cache,
+                             struct btrfs_trans_handle *trans,
+                             int load_cache_only)
 {
         struct btrfs_fs_info *fs_info = cache->fs_info;
         struct btrfs_caching_control *caching_ctl;
@@ -432,6 +434,36 @@ static int cache_block_group(struct btrfs_block_group_cache *cache)
         if (cache->cached != BTRFS_CACHE_NO)
                 return 0;
 
+        /*
+         * We can't do the read from on-disk cache during a commit since we need
+         * to have the normal tree locking.
+         */
+        if (!trans->transaction->in_commit) {
+                spin_lock(&cache->lock);
+                if (cache->cached != BTRFS_CACHE_NO) {
+                        spin_unlock(&cache->lock);
+                        return 0;
+                }
+                cache->cached = BTRFS_CACHE_STARTED;
+                spin_unlock(&cache->lock);
+
+                ret = load_free_space_cache(fs_info, cache);
+
+                spin_lock(&cache->lock);
+                if (ret == 1) {
+                        cache->cached = BTRFS_CACHE_FINISHED;
+                        cache->last_byte_to_unpin = (u64)-1;
+                } else {
+                        cache->cached = BTRFS_CACHE_NO;
+                }
+                spin_unlock(&cache->lock);
+                if (ret == 1)
+                        return 0;
+        }
+
+        if (load_cache_only)
+                return 0;
+
         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_KERNEL);
         BUG_ON(!caching_ctl);
 
@@ -3984,6 +4016,14 @@ static int update_block_group(struct btrfs_trans_handle *trans,
                         factor = 2;
                 else
                         factor = 1;
+                /*
+                 * If this block group has free space cache written out, we
+                 * need to make sure to load it if we are removing space.  This
+                 * is because we need the unpinning stage to actually add the
+                 * space back to the block group, otherwise we will leak space.
+                 */
+                if (!alloc && cache->cached == BTRFS_CACHE_NO)
+                        cache_block_group(cache, trans, 1);
 
                 byte_in_group = bytenr - cache->key.objectid;
                 WARN_ON(byte_in_group > cache->key.offset);
@@ -4828,6 +4868,10 @@ have_block_group:
                 if (unlikely(block_group->cached == BTRFS_CACHE_NO)) {
                         u64 free_percent;
 
+                        ret = cache_block_group(block_group, trans, 1);
+                        if (block_group->cached == BTRFS_CACHE_FINISHED)
+                                goto have_block_group;
+
                         free_percent = btrfs_block_group_used(&block_group->item);
                         free_percent *= 100;
                         free_percent = div64_u64(free_percent,
@@ -4848,7 +4892,7 @@ have_block_group:
                         if (loop > LOOP_CACHING_NOWAIT ||
                             (loop > LOOP_FIND_IDEAL &&
                              atomic_read(&space_info->caching_threads) < 2)) {
-                                ret = cache_block_group(block_group);
+                                ret = cache_block_group(block_group, trans, 0);
                                 BUG_ON(ret);
                         }
                         found_uncached_bg = true;
@@ -5405,7 +5449,7 @@ int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
         u64 num_bytes = ins->offset;
 
         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
-        cache_block_group(block_group);
+        cache_block_group(block_group, trans, 0);
         caching_ctl = get_caching_control(block_group);
 
         if (!caching_ctl) {