Btrfs: remove some unnecessary spin_lock usages
We use mutex lock to protect all the user change operations.
So when we are calling find_qgroup_rb() to check whether qgroup
exists, we don't have to hold spin_lock.
Besides, when enabling/disabling quota, it must be single thread
when operations come here. spin lock must be firstly used to
clear quota_root when disabling quota, while enabling quota, spin
lock must be used to complete the last assign work.
Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 0a1f686..49c4e63 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -98,7 +98,7 @@
struct btrfs_qgroup *member;
};
-/* must be called with qgroup_lock held */
+/* must be called with qgroup_ioctl_lock held */
static struct btrfs_qgroup *find_qgroup_rb(struct btrfs_fs_info *fs_info,
u64 qgroupid)
{
@@ -792,13 +792,10 @@
int slot;
mutex_lock(&fs_info->qgroup_ioctl_lock);
- spin_lock(&fs_info->qgroup_lock);
if (fs_info->quota_root) {
fs_info->pending_quota_state = 1;
- spin_unlock(&fs_info->qgroup_lock);
goto out;
}
- spin_unlock(&fs_info->qgroup_lock);
/*
* initially create the quota tree
@@ -860,14 +857,11 @@
if (ret)
goto out_free_path;
- spin_lock(&fs_info->qgroup_lock);
qgroup = add_qgroup_rb(fs_info, found_key.offset);
if (IS_ERR(qgroup)) {
- spin_unlock(&fs_info->qgroup_lock);
ret = PTR_ERR(qgroup);
goto out_free_path;
}
- spin_unlock(&fs_info->qgroup_lock);
}
ret = btrfs_next_item(tree_root, path);
if (ret < 0)
@@ -882,13 +876,12 @@
if (ret)
goto out_free_path;
- spin_lock(&fs_info->qgroup_lock);
qgroup = add_qgroup_rb(fs_info, BTRFS_FS_TREE_OBJECTID);
if (IS_ERR(qgroup)) {
- spin_unlock(&fs_info->qgroup_lock);
ret = PTR_ERR(qgroup);
goto out_free_path;
}
+ spin_lock(&fs_info->qgroup_lock);
fs_info->quota_root = quota_root;
fs_info->pending_quota_state = 1;
spin_unlock(&fs_info->qgroup_lock);
@@ -913,11 +906,9 @@
int ret = 0;
mutex_lock(&fs_info->qgroup_ioctl_lock);
- spin_lock(&fs_info->qgroup_lock);
- if (!fs_info->quota_root) {
- spin_unlock(&fs_info->qgroup_lock);
+ if (!fs_info->quota_root)
goto out;
- }
+ spin_lock(&fs_info->qgroup_lock);
fs_info->quota_enabled = 0;
fs_info->pending_quota_state = 0;
quota_root = fs_info->quota_root;
@@ -1060,16 +1051,13 @@
}
/* check if there are no relations to this qgroup */
- spin_lock(&fs_info->qgroup_lock);
qgroup = find_qgroup_rb(fs_info, qgroupid);
if (qgroup) {
if (!list_empty(&qgroup->groups) || !list_empty(&qgroup->members)) {
- spin_unlock(&fs_info->qgroup_lock);
ret = -EBUSY;
goto out;
}
}
- spin_unlock(&fs_info->qgroup_lock);
ret = del_qgroup_item(trans, quota_root, qgroupid);
@@ -1106,20 +1094,17 @@
(unsigned long long)qgroupid);
}
- spin_lock(&fs_info->qgroup_lock);
-
qgroup = find_qgroup_rb(fs_info, qgroupid);
if (!qgroup) {
ret = -ENOENT;
- goto unlock;
+ goto out;
}
+ spin_lock(&fs_info->qgroup_lock);
qgroup->lim_flags = limit->flags;
qgroup->max_rfer = limit->max_rfer;
qgroup->max_excl = limit->max_excl;
qgroup->rsv_rfer = limit->rsv_rfer;
qgroup->rsv_excl = limit->rsv_excl;
-
-unlock:
spin_unlock(&fs_info->qgroup_lock);
out:
mutex_unlock(&fs_info->qgroup_ioctl_lock);