Btrfs: run chunk allocations while we do delayed refs

Btrfs tries to batch extent allocation tree changes to improve performance
and reduce metadata trashing.  But it doesn't allocate new metadata chunks
while it is doing allocations for the extent allocation tree.

This commit changes the delayed refence code to do chunk allocations if we're
getting low on room.  It prevents crashes and improves performance.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
(cherry picked from commit 203bf287cb01a5dc26c20bd3737cecf3aeba1d48)

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 8603ee4e3dfd75fb96db37b5f12deb8deb043838..cdbf875db9c5984a15631871c35d92df14dbd303 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2267,9 +2267,7 @@ static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
                                BUG_ON(ret);
                                kfree(extent_op);
 
-                               cond_resched();
-                               spin_lock(&delayed_refs->lock);
-                               continue;
+                               goto next;
                        }
 
                        list_del_init(&locked_ref->cluster);
@@ -2289,7 +2287,11 @@ static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
                btrfs_put_delayed_ref(ref);
                kfree(extent_op);
                count++;
-
+next:
+               do_chunk_alloc(trans, root->fs_info->extent_root,
+                              2 * 1024 * 1024,
+                              btrfs_get_alloc_profile(root, 0),
+                              CHUNK_ALLOC_NO_FORCE);
                cond_resched();
                spin_lock(&delayed_refs->lock);
        }
@@ -2317,6 +2319,10 @@ int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
        if (root == root->fs_info->extent_root)
                root = root->fs_info->tree_root;
 
+       do_chunk_alloc(trans, root->fs_info->extent_root,
+                      2 * 1024 * 1024, btrfs_get_alloc_profile(root, 0),
+                      CHUNK_ALLOC_NO_FORCE);
+
        delayed_refs = &trans->transaction->delayed_refs;
        INIT_LIST_HEAD(&cluster);
 again:

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 81376d94cd3c6a4639ebef35df501dbefbfb2435..360c2dfd1ee64bb8af741023ad7bbc45badf8fde 100644 (file)
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -467,19 +467,12 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
 
        btrfs_trans_release_metadata(trans, root);
        trans->block_rsv = NULL;
-       while (count < 4) {
+       while (count < 2) {
                unsigned long cur = trans->delayed_ref_updates;
                trans->delayed_ref_updates = 0;
                if (cur &&
                    trans->transaction->delayed_refs.num_heads_ready > 64) {
                        trans->delayed_ref_updates = 0;
-
-                       /*
-                        * do a full flush if the transaction is trying
-                        * to close
-                        */
-                       if (trans->transaction->delayed_refs.flushing)
-                               cur = 0;
                        btrfs_run_delayed_refs(trans, root, cur);
                } else {
                        break;