list_first_entry is essentially a wrapper over cotnainer_of. The latter
can never return null even if it's working on inconsistent list since it
will either crash or return some offset in the wrong struct.
Additionally, for the dirty_bgs list the iteration is done under
dirty_bgs_lock which ensures consistency of the list.

Signed-off-by: Nikolay Borisov <nbori...@suse.com>
---
 fs/btrfs/disk-io.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index aca906971abe..1b3989c54d7c 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -4323,11 +4323,6 @@ void btrfs_cleanup_dirty_bgs(struct btrfs_transaction 
*cur_trans,
                cache = list_first_entry(&cur_trans->dirty_bgs,
                                         struct btrfs_block_group_cache,
                                         dirty_list);
-               if (!cache) {
-                       btrfs_err(fs_info, "orphan block group dirty_bgs list");
-                       spin_unlock(&cur_trans->dirty_bgs_lock);
-                       return;
-               }
 
                if (!list_empty(&cache->io_list)) {
                        spin_unlock(&cur_trans->dirty_bgs_lock);
@@ -4351,10 +4346,6 @@ void btrfs_cleanup_dirty_bgs(struct btrfs_transaction 
*cur_trans,
                cache = list_first_entry(&cur_trans->io_bgs,
                                         struct btrfs_block_group_cache,
                                         io_list);
-               if (!cache) {
-                       btrfs_err(fs_info, "orphan block group on io_bgs list");
-                       return;
-               }
 
                list_del_init(&cache->io_list);
                spin_lock(&cache->lock);
-- 
2.7.4

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