6 files changed, 17 insertions, 6 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 7e607416755a..0b180708bf79 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1171,6 +1171,7 @@ struct btrfs_space_info {
         struct percpu_counter total_bytes_pinned;
 
         struct list_head list;
+        /* Protected by the spinlock 'lock'. */
         struct list_head ro_bgs;
 
         struct rw_semaphore groups_sem;
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 15116585e714..a684086c3c81 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -9422,7 +9422,6 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
          * are still on the list after taking the semaphore
          */
         list_del_init(&block_group->list);
-        list_del_init(&block_group->ro_list);
         if (list_empty(&block_group->space_info->block_groups[index])) {
                 kobj = block_group->space_info->block_group_kobjs[index];
                 block_group->space_info->block_group_kobjs[index] = NULL;
@@ -9464,6 +9463,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
         btrfs_remove_free_space_cache(block_group);
 
         spin_lock(&block_group->space_info->lock);
+        list_del_init(&block_group->ro_list);
         block_group->space_info->total_bytes -= block_group->key.offset;
         block_group->space_info->bytes_readonly -= block_group->key.offset;
         block_group->space_info->disk_total -= block_group->key.offset * factor;
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 4ebabd237153..790dbae3343c 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2190,7 +2190,7 @@ void btrfs_free_io_failure_record(struct inode *inode, u64 start, u64 end)
 
                 next = next_state(state);
 
-                failrec = (struct io_failure_record *)state->private;
+                failrec = (struct io_failure_record *)(unsigned long)state->private;
                 free_extent_state(state);
                 kfree(failrec);
 
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 9e1569ffbf6e..2f0fbc374e87 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -3053,7 +3053,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
 
         ppath = btrfs_alloc_path();
         if (!ppath) {
-                btrfs_free_path(ppath);
+                btrfs_free_path(path);
                 return -ENOMEM;
         }
 
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 60f7cbe815e9..6f49b2872a64 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1000,10 +1000,20 @@ int btrfs_sync_fs(struct super_block *sb, int wait)
                          */
                         if (fs_info->pending_changes == 0)
                                 return 0;
+                        /*
+                         * A non-blocking test if the fs is frozen. We must not
+                         * start a new transaction here otherwise a deadlock
+                         * happens. The pending operations are delayed to the
+                         * next commit after thawing.
+                         */
+                        if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
+                                __sb_end_write(sb, SB_FREEZE_WRITE);
+                        else
+                                return 0;
                         trans = btrfs_start_transaction(root, 0);
-                } else {
-                        return PTR_ERR(trans);
                 }
+                if (IS_ERR(trans))
+                        return PTR_ERR(trans);
         }
         return btrfs_commit_transaction(trans, root);
 }
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index a605d4e2f2bc..e88b59d13439 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -2118,7 +2118,7 @@ void btrfs_apply_pending_changes(struct btrfs_fs_info *fs_info)
         unsigned long prev;
         unsigned long bit;
 
-        prev = cmpxchg(&fs_info->pending_changes, 0, 0);
+        prev = xchg(&fs_info->pending_changes, 0);
         if (!prev)
                 return;