1 files changed, 24 insertions, 6 deletions

diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 6e08405892ae..a878cea70f4c 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -37,6 +37,7 @@ static DEFINE_MUTEX(eventfs_mutex);
 
 struct eventfs_root_inode {
 	struct eventfs_inode		ei;
+	struct inode			*parent_inode;
 	struct dentry			*events_dir;
 };
 
@@ -226,12 +227,23 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
 
 static void update_events_attr(struct eventfs_inode *ei, struct super_block *sb)
 {
-	struct inode *root;
+	struct eventfs_root_inode *rei;
+	struct inode *parent;
+
+	rei = get_root_inode(ei);
+
+	/* Use the parent inode permissions unless root set its permissions */
+	parent = rei->parent_inode;
 
-	/* Get the tracefs root inode. */
-	root = d_inode(sb->s_root);
-	ei->attr.uid = root->i_uid;
-	ei->attr.gid = root->i_gid;
+	if (rei->ei.attr.mode & EVENTFS_SAVE_UID)
+		ei->attr.uid = rei->ei.attr.uid;
+	else
+		ei->attr.uid = parent->i_uid;
+
+	if (rei->ei.attr.mode & EVENTFS_SAVE_GID)
+		ei->attr.gid = rei->ei.attr.gid;
+	else
+		ei->attr.gid = parent->i_gid;
 }
 
 static void set_top_events_ownership(struct inode *inode)
@@ -817,6 +829,7 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
 	// Note: we have a ref to the dentry from tracefs_start_creating()
 	rei = get_root_inode(ei);
 	rei->events_dir = dentry;
+	rei->parent_inode = d_inode(dentry->d_sb->s_root);
 
 	ei->entries = entries;
 	ei->nr_entries = size;
@@ -826,10 +839,15 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
 	uid = d_inode(dentry->d_parent)->i_uid;
 	gid = d_inode(dentry->d_parent)->i_gid;
 
-	/* This is used as the default ownership of the files and directories */
 	ei->attr.uid = uid;
 	ei->attr.gid = gid;
 
+	/*
+	 * When the "events" directory is created, it takes on the
+	 * permissions of its parent. But can be reset on remount.
+	 */
+	ei->attr.mode |= EVENTFS_SAVE_UID | EVENTFS_SAVE_GID;
+
 	INIT_LIST_HEAD(&ei->children);
 	INIT_LIST_HEAD(&ei->list);