[RFC PATCH] btrfs: flush_space: treat return value of do_chunk_alloc properly

[Alex Lyakas <alex@xxxxxxxxxxxxxxxxx>]

do_chunk_alloc returns 1 when it succeeds to allocate a new chunk.
But flush_space will not convert this to 0, and will also return 1.
As a result, reserve_metadata_bytes will think that flush_space failed,
and may potentially return this value "1" to the caller (depends how
reserve_metadata_bytes was called). The caller will also treat this as an error.
For example, btrfs_block_rsv_refill does:

int ret = -ENOSPC;
...
ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
if (!ret) {
        block_rsv_add_bytes(block_rsv, num_bytes, 0);
        return 0;
}

return ret;

So it will return -ENOSPC.

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 4b89680..1ba3f0d 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4727,7 +4727,7 @@ static int flush_space(struct btrfs_root *root,
                                     btrfs_get_alloc_profile(root, 0),
                                     CHUNK_ALLOC_NO_FORCE);
                btrfs_end_transaction(trans, root);
-               if (ret == -ENOSPC)
+               if (ret > 0 || ret == -ENOSPC)
                        ret = 0;
                break;
        case COMMIT_TRANS:
--
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