Merge tag 'for-5.7-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave...

Pull btrfs fix from David Sterba:
 "A regression fix for a warning caused by running balance and snapshot
  creation in parallel"

* tag 'for-5.7-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix setting last_trans for reloc roots

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 7e362a6935fd455d8a99cbdc3c438d61c524e9f9..d35936c934ab0dacc8623b800c3843fc09a7cca3 100644 (file)
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1527,8 +1527,7 @@ int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
        int clear_rsv = 0;
        int ret;
 
-       if (!rc || !rc->create_reloc_tree ||
-           root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
+       if (!rc)
                return 0;
 
        /*
@@ -1538,12 +1537,28 @@ int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
        if (reloc_root_is_dead(root))
                return 0;
 
+       /*
+        * This is subtle but important.  We do not do
+        * record_root_in_transaction for reloc roots, instead we record their
+        * corresponding fs root, and then here we update the last trans for the
+        * reloc root.  This means that we have to do this for the entire life
+        * of the reloc root, regardless of which stage of the relocation we are
+        * in.
+        */
        if (root->reloc_root) {
                reloc_root = root->reloc_root;
                reloc_root->last_trans = trans->transid;
                return 0;
        }
 
+       /*
+        * We are merging reloc roots, we do not need new reloc trees.  Also
+        * reloc trees never need their own reloc tree.
+        */
+       if (!rc->create_reloc_tree ||
+           root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
+               return 0;
+
        if (!trans->reloc_reserved) {
                rsv = trans->block_rsv;
                trans->block_rsv = rc->block_rsv;