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eventfs: Do not use attributes for events directory

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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 <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Google) 2024-05-22 12:49:46 -04:00
parent 6e3d7c903c
commit 2dd00ac1d3
1 changed files with 7 additions and 7 deletions
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12
fs/tracefs/event_inode.c
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@ -210,6 +210,8 @@ 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) {
/* Just use the inode permissions for the events directory */
if (!ei->is_events)
update_attr(&ei->attr, iattr);
} else {
@ -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);