Merge branches 'clk-range', 'clk-uniphier', 'clk-apple' and 'clk-qcom' into clk-next

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

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 8928275..f12dc68 100644 (file)
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1185,9 +1185,24 @@ int btrfs_quota_disable(struct btrfs_fs_info *fs_info)
        struct btrfs_trans_handle *trans = NULL;
        int ret = 0;
 
+       /*
+        * We need to have subvol_sem write locked, to prevent races between
+        * concurrent tasks trying to disable quotas, because we will unlock
+        * and relock qgroup_ioctl_lock across BTRFS_FS_QUOTA_ENABLED changes.
+        */
+       lockdep_assert_held_write(&fs_info->subvol_sem);
+
        mutex_lock(&fs_info->qgroup_ioctl_lock);
        if (!fs_info->quota_root)
                goto out;
+
+       /*
+        * Request qgroup rescan worker to complete and wait for it. This wait
+        * must be done before transaction start for quota disable since it may
+        * deadlock with transaction by the qgroup rescan worker.
+        */
+       clear_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
+       btrfs_qgroup_wait_for_completion(fs_info, false);
        mutex_unlock(&fs_info->qgroup_ioctl_lock);
 
        /*
@@ -1205,14 +1220,13 @@ int btrfs_quota_disable(struct btrfs_fs_info *fs_info)
        if (IS_ERR(trans)) {
                ret = PTR_ERR(trans);
                trans = NULL;
+               set_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
                goto out;
        }
 
        if (!fs_info->quota_root)
                goto out;
 
-       clear_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
-       btrfs_qgroup_wait_for_completion(fs_info, false);
        spin_lock(&fs_info->qgroup_lock);
        quota_root = fs_info->quota_root;
        fs_info->quota_root = NULL;
@@ -3383,6 +3397,9 @@ qgroup_rescan_init(struct btrfs_fs_info *fs_info, u64 progress_objectid,
                        btrfs_warn(fs_info,
                        "qgroup rescan init failed, qgroup is not enabled");
                        ret = -EINVAL;
+               } else if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
+                       /* Quota disable is in progress */
+                       ret = -EBUSY;
                }
 
                if (ret) {