[V2,3/6] Btrfs: fix missing check before updating qgroup limit

Commit Message

Wang Shilong March 28, 2013, 10:54 a.m. UTC

From: Wang Shilong <[e-mail]>

We should check whether a qgroup exists before updating qgroup limit,
if the relative qgroup dosen't exsit, return -EEXIST and do not join
a transaction, fix it.

Signed-off-by: Wang Shilong <[e-mail]>
Reviewed-by: Miao Xie <[e-mail]>
---
 fs/btrfs/ctree.h  |    1 +
 fs/btrfs/ioctl.c  |   18 ++++++++++--------
 fs/btrfs/qgroup.c |   15 ++++++++++++---
 3 files changed, 23 insertions(+), 11 deletions(-)

Patch

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index a11a8ed..3fc393d 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3094,6 +3094,7 @@  int btrfs_make_block_group(struct btrfs_trans_handle *trans,
 			   struct btrfs_root *root, u64 bytes_used,
 			   u64 type, u64 chunk_objectid, u64 chunk_offset,
 			   u64 size);
+int btrfs_may_limit_qgroup(struct btrfs_root *root, u64 qgroupid);
 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 			     struct btrfs_root *root, u64 group_start);
 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index e2950f1..7c72b12 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3859,20 +3859,22 @@  static long btrfs_ioctl_qgroup_limit(struct file *file, void __user *arg)
 		ret = PTR_ERR(sa);
 		goto drop_write;
 	}
-	mutex_lock(&root->fs_info->quota_lock);
-	trans = btrfs_join_transaction(root);
-	if (IS_ERR(trans)) {
-		ret = PTR_ERR(trans);
-		goto out;
-	}
-
 	qgroupid = sa->qgroupid;
 	if (!qgroupid) {
 		/* take the current subvol as qgroup */
 		qgroupid = root->root_key.objectid;
 	}
 
-	/* FIXME: check if the IDs really exist */
+	mutex_lock(&root->fs_info->quota_lock);
+	ret = btrfs_may_limit_qgroup(root, qgroupid);
+	if (ret)
+		goto out;
+
+	trans = btrfs_join_transaction(root);
+	if (IS_ERR(trans)) {
+		ret = PTR_ERR(trans);
+		goto out;
+	}
 	ret = btrfs_limit_qgroup(trans, root->fs_info, qgroupid, &sa->lim);
 
 	err = btrfs_end_transaction(trans, root);
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 7df372a..bed0e22 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1059,9 +1059,6 @@  int btrfs_limit_qgroup(struct btrfs_trans_handle *trans,
 	struct btrfs_qgroup *qgroup;
 	int ret = 0;
 
-	if (!quota_root)
-		return -EINVAL;
-
 	ret = update_qgroup_limit_item(trans, quota_root, qgroupid,
 				       limit->flags, limit->max_rfer,
 				       limit->max_excl, limit->rsv_rfer,
@@ -1665,3 +1662,15 @@  void assert_qgroups_uptodate(struct btrfs_trans_handle *trans)
 		trans->delayed_ref_elem.seq);
 	BUG();
 }
+
+int btrfs_may_limit_qgroup(struct btrfs_root *root, u64 qgroupid)
+{
+	struct btrfs_qgroup *qgroup = NULL;
+
+	if (!root->fs_info->quota_root)
+		return -EINVAL;
+	qgroup = find_qgroup_rb(root->fs_info, qgroupid);
+	if (!qgroup)
+		return -ENOENT;
+	return 0;
+}