Btrfs: Introduce global metadata reservation

Reserve metadata space for extent tree, checksum tree and root tree

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 58 insertions, 12 deletions

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 2616491a5c5b..6217bb6d516a 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -321,10 +321,36 @@ void btrfs_throttle(struct btrfs_root *root)
         mutex_unlock(&root->fs_info->trans_mutex);
 }
 
+static int should_end_transaction(struct btrfs_trans_handle *trans,
+                                  struct btrfs_root *root)
+{
+        int ret;
+        ret = btrfs_block_rsv_check(trans, root,
+                                    &root->fs_info->global_block_rsv, 0, 5);
+        return ret ? 1 : 0;
+}
+
+int btrfs_should_end_transaction(struct btrfs_trans_handle *trans,
+                                 struct btrfs_root *root)
+{
+        struct btrfs_transaction *cur_trans = trans->transaction;
+        int updates;
+
+        if (cur_trans->blocked || cur_trans->delayed_refs.flushing)
+                return 1;
+
+        updates = trans->delayed_ref_updates;
+        trans->delayed_ref_updates = 0;
+        if (updates)
+                btrfs_run_delayed_refs(trans, root, updates);
+
+        return should_end_transaction(trans, root);
+}
+
 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
                           struct btrfs_root *root, int throttle)
 {
-        struct btrfs_transaction *cur_trans;
+        struct btrfs_transaction *cur_trans = trans->transaction;
         struct btrfs_fs_info *info = root->fs_info;
         int count = 0;
 
@@ -350,9 +376,19 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
 
         btrfs_trans_release_metadata(trans, root);
 
+        if (!root->fs_info->open_ioctl_trans &&
+            should_end_transaction(trans, root))
+                trans->transaction->blocked = 1;
+
+        if (cur_trans->blocked && !cur_trans->in_commit) {
+                if (throttle)
+                        return btrfs_commit_transaction(trans, root);
+                else
+                        wake_up_process(info->transaction_kthread);
+        }
+
         mutex_lock(&info->trans_mutex);
-        cur_trans = info->running_transaction;
-        WARN_ON(cur_trans != trans->transaction);
+        WARN_ON(cur_trans != info->running_transaction);
         WARN_ON(cur_trans->num_writers < 1);
         cur_trans->num_writers--;
 
@@ -664,30 +700,30 @@ static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
 int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
 {
         struct btrfs_fs_info *info = root->fs_info;
-        int ret;
         struct btrfs_trans_handle *trans;
+        int ret;
         unsigned long nr;
 
-        smp_mb();
-        if (root->defrag_running)
+        if (xchg(&root->defrag_running, 1))
                 return 0;
-        trans = btrfs_start_transaction(root, 1);
+
         while (1) {
-                root->defrag_running = 1;
+                trans = btrfs_start_transaction(root, 0);
+                if (IS_ERR(trans))
+                        return PTR_ERR(trans);
+
                 ret = btrfs_defrag_leaves(trans, root, cacheonly);
+
                 nr = trans->blocks_used;
                 btrfs_end_transaction(trans, root);
                 btrfs_btree_balance_dirty(info->tree_root, nr);
                 cond_resched();
 
-                trans = btrfs_start_transaction(root, 1);
                 if (root->fs_info->closing || ret != -EAGAIN)
                         break;
         }
         root->defrag_running = 0;
-        smp_mb();
-        btrfs_end_transaction(trans, root);
-        return 0;
+        return ret;
 }
 
 #if 0
@@ -924,6 +960,16 @@ int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
         return ret;
 }
 
+int btrfs_transaction_blocked(struct btrfs_fs_info *info)
+{
+        int ret = 0;
+        spin_lock(&info->new_trans_lock);
+        if (info->running_transaction)
+                ret = info->running_transaction->blocked;
+        spin_unlock(&info->new_trans_lock);
+        return ret;
+}
+
 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                              struct btrfs_root *root)
 {