Btrfs: Fix handling of space info full during allocations

When we fail to allocate a new block group, we should still do the
checks to make sure allocations try again with the minimum requested
allocation size.

This also fixes a deadlock that come from a missed down_read in
the chunk allocation failure handling.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index b7530c3ac206..22820f91d2b0 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2301,9 +2301,9 @@ new_group_no_lock:
                                 up_read(&space_info->groups_sem);
                                 ret = do_chunk_alloc(trans, root, num_bytes +
                                                      2 * 1024 * 1024, data, 1);
-                                if (ret < 0)
-                                        break;
                                 down_read(&space_info->groups_sem);
+                                if (ret < 0)
+                                        goto loop_check;
                                 head = &space_info->block_groups;
                                 /*
                                  * we've allocated a new chunk, keep
@@ -2314,6 +2314,7 @@ new_group_no_lock:
                         } else if (!allowed_chunk_alloc) {
                                 space_info->force_alloc = 1;
                         }
+loop_check:
                         if (keep_going) {
                                 cur = head->next;
                                 extra_loop = 0;