From 2dd00ac1d38afba1b59e439abc300a9b0ce696bf Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" Date: Wed, 22 May 2024 12:49:46 -0400 Subject: [PATCH] eventfs: Do not use attributes for events directory The top "events" directory has a static inode (it's created when it is and removed when the directory is removed). There's no need to use the events ei->attr to determine its permissions. But it is used for saving the permissions of the "events" directory for when it is created, as that is needed for the default permissions for the files and directories underneath it. For example: # cd /sys/kernel/tracing # mkdir instances/foo # chown 1001 instances/foo/events The files under instances/foo/events should still have the same owner as instances/foo (which the instances/foo/events ei->attr will hold), but the events directory now has owner 1001. Link: https://lore.kernel.org/lkml/20240522165032.104981011@goodmis.org Cc: Linus Torvalds Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Cc: Andrew Morton Signed-off-by: Steven Rostedt (Google) --- fs/tracefs/event_inode.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c index 320e49056d3a..5d88c184f0fc 100644 --- a/fs/tracefs/event_inode.c +++ b/fs/tracefs/event_inode.c @@ -210,7 +210,9 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry, * determined by the parent directory. */ if (dentry->d_inode->i_mode & S_IFDIR) { - update_attr(&ei->attr, iattr); + /* Just use the inode permissions for the events directory */ + if (!ei->is_events) + update_attr(&ei->attr, iattr); } else { name = dentry->d_name.name; @@ -789,15 +791,13 @@ 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; + /* + * The ei->attr will be used as the default values for the + * files beneath this directory. + */ 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);