Merge tag 'v4.17-rc2' into docs-next

[linux-2.6-microblaze.git] / fs / btrfs / qgroup.c

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index f583f13..9fb758d 100644 (file)
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1,19 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (C) 2011 STRATO.  All rights reserved.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public
- * License v2 as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public
- * License along with this program; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 021110-1307, USA.
  */
 
 #include <linux/sched.h>
@@ -24,6 +11,7 @@
 #include <linux/slab.h>
 #include <linux/workqueue.h>
 #include <linux/btrfs.h>
+#include <linux/sizes.h>
 
 #include "ctree.h"
 #include "transaction.h"
@@ -2388,8 +2376,21 @@ out:
        return ret;
 }
 
-static bool qgroup_check_limits(const struct btrfs_qgroup *qg, u64 num_bytes)
+/*
+ * Two limits to commit transaction in advance.
+ *
+ * For RATIO, it will be 1/RATIO of the remaining limit
+ * (excluding data and prealloc meta) as threshold.
+ * For SIZE, it will be in byte unit as threshold.
+ */
+#define QGROUP_PERTRANS_RATIO          32
+#define QGROUP_PERTRANS_SIZE           SZ_32M
+static bool qgroup_check_limits(struct btrfs_fs_info *fs_info,
+                               const struct btrfs_qgroup *qg, u64 num_bytes)
 {
+       u64 limit;
+       u64 threshold;
+
        if ((qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_RFER) &&
            qgroup_rsv_total(qg) + (s64)qg->rfer + num_bytes > qg->max_rfer)
                return false;
@@ -2398,6 +2399,31 @@ static bool qgroup_check_limits(const struct btrfs_qgroup *qg, u64 num_bytes)
            qgroup_rsv_total(qg) + (s64)qg->excl + num_bytes > qg->max_excl)
                return false;
 
+       /*
+        * Even if we passed the check, it's better to check if reservation
+        * for meta_pertrans is pushing us near limit.
+        * If there is too much pertrans reservation or it's near the limit,
+        * let's try commit transaction to free some, using transaction_kthread
+        */
+       if ((qg->lim_flags & (BTRFS_QGROUP_LIMIT_MAX_RFER |
+                             BTRFS_QGROUP_LIMIT_MAX_EXCL))) {
+               if (qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_EXCL)
+                       limit = qg->max_excl;
+               else
+                       limit = qg->max_rfer;
+               threshold = (limit - qg->rsv.values[BTRFS_QGROUP_RSV_DATA] -
+                           qg->rsv.values[BTRFS_QGROUP_RSV_META_PREALLOC]) /
+                           QGROUP_PERTRANS_RATIO;
+               threshold = min_t(u64, threshold, QGROUP_PERTRANS_SIZE);
+
+               /*
+                * Use transaction_kthread to commit transaction, so we no
+                * longer need to bother nested transaction nor lock context.
+                */
+               if (qg->rsv.values[BTRFS_QGROUP_RSV_META_PERTRANS] > threshold)
+                       btrfs_commit_transaction_locksafe(fs_info);
+       }
+
        return true;
 }
 
@@ -2447,7 +2473,7 @@ static int qgroup_reserve(struct btrfs_root *root, u64 num_bytes, bool enforce,
 
                qg = unode_aux_to_qgroup(unode);
 
-               if (enforce && !qgroup_check_limits(qg, num_bytes)) {
+               if (enforce && !qgroup_check_limits(fs_info, qg, num_bytes)) {
                        ret = -EDQUOT;
                        goto out;
                }