From: Wang Shilong <wangsl-fnst@xxxxxxxxxxxxxx>
We use mutex_lock to protect all the user change operaions.
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 to here.Spin_lock must be fistly
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@xxxxxxxxxxxxxx>
Reviewed-by: Miao Xie <miaox@xxxxxxxxxxxxxx>
---
fs/btrfs/qgroup.c | 42 +++++++++++++++---------------------------
1 files changed, 15 insertions(+), 27 deletions(-)
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index e3598fa..7df372a 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -42,7 +42,6 @@
* - limit
* - caches fuer ulists
* - performance benchmarks
- * - check all ioctl parameters
*/
/*
@@ -98,7 +97,11 @@ struct btrfs_qgroup_list {
struct btrfs_qgroup *member;
};
-/* must be called with qgroup_lock held */
+/*
+ * don't need to be held by spin_lock since
+ * all the quota configurations on memory has been protected
+ * by mutex quota_lock.
+ */
static struct btrfs_qgroup *find_qgroup_rb(struct btrfs_fs_info *fs_info,
u64 qgroupid)
{
@@ -793,13 +796,10 @@ int btrfs_quota_enable(struct btrfs_trans_handle *trans,
int ret = 0;
int slot;
- 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;
+ return ret;
}
- spin_unlock(&fs_info->qgroup_lock);
/*
* initially create the quota tree
@@ -808,7 +808,7 @@ int btrfs_quota_enable(struct btrfs_trans_handle *trans,
BTRFS_QUOTA_TREE_OBJECTID);
if (IS_ERR(quota_root)) {
ret = PTR_ERR(quota_root);
- goto out;
+ return ret;
}
path = btrfs_alloc_path();
@@ -861,14 +861,11 @@ int btrfs_quota_enable(struct btrfs_trans_handle *trans,
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)
@@ -883,13 +880,12 @@ out_add_root:
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);
@@ -901,7 +897,6 @@ out_free_root:
free_extent_buffer(quota_root->commit_root);
kfree(quota_root);
}
-out:
return ret;
}
@@ -912,11 +907,10 @@ int btrfs_quota_disable(struct btrfs_trans_handle *trans,
struct btrfs_root *quota_root;
int ret = 0;
- spin_lock(&fs_info->qgroup_lock);
- if (!fs_info->quota_root) {
- spin_unlock(&fs_info->qgroup_lock);
+ if (!fs_info->quota_root)
return 0;
- }
+
+ spin_lock(&fs_info->qgroup_lock);
fs_info->quota_enabled = 0;
fs_info->pending_quota_state = 0;
quota_root = fs_info->quota_root;
@@ -1041,15 +1035,12 @@ int btrfs_remove_qgroup(struct btrfs_trans_handle *trans,
return -EINVAL;
/* 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);
+ if (!list_empty(&qgroup->groups) ||
+ !list_empty(&qgroup->members))
return -EBUSY;
- }
}
- spin_unlock(&fs_info->qgroup_lock);
ret = del_qgroup_item(trans, quota_root, qgroupid);
@@ -1081,20 +1072,17 @@ int btrfs_limit_qgroup(struct btrfs_trans_handle *trans,
(unsigned long long)qgroupid);
}
- spin_lock(&fs_info->qgroup_lock);
-
qgroup = find_qgroup_rb(fs_info, qgroupid);
if (!qgroup) {
ret = -ENOENT;
- goto unlock;
+ return ret;
}
+ 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);
return ret;
--
1.7.7.6
--
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