Merge tag 'trace-tracefs-v6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracefs/eventfs updates from Steven Rostedt:
 "Bug fixes:

   - The eventfs directories need to have unique inode numbers. Make
     sure that they do not get the default file inode number.

   - Update the inode uid and gid fields on remount.

     When a remount happens where a uid and/or gid is specified, all the
     tracefs files and directories should get the specified uid and/or
     gid. But this can be sporadic when some uids were assigned already.
     There's already a list of inodes that are allocated. Just update
     their uid and gid fields at the time of remount.

   - Update the eventfs_inodes on remount from the top level "events"
     descriptor.

     There was a bug where not all the eventfs files or directories
     where getting updated on remount. One fix was to clear the
     SAVED_UID/GID flags from the inode list during the iteration of the
     inodes during the remount. But because the eventfs inodes can be
     freed when the last referenced is released, not all the
     eventfs_inodes were being updated. This lead to the ownership
     selftest to fail if it was run a second time (the first time would
     leave eventfs_inodes with no corresponding tracefs_inode).

     Instead, for eventfs_inodes, only process the "events"
     eventfs_inode from the list iteration, as it is guaranteed to have
     a tracefs_inode (it's never freed while the "events" directory
     exists). As it has a list of its children, and the children have a
     list of their children, just iterate all the eventfs_inodes from
     the "events" descriptor and it is guaranteed to get all of them.

   - Clear the EVENT_INODE flag from the tracefs_drop_inode() callback.

     Currently the EVENTFS_INODE FLAG is cleared in the tracefs_d_iput()
     callback. But this is the wrong location. The iput() callback is
     called when the last reference to the dentry inode is hit. There
     could be a case where two dentry's have the same inode, and the
     flag will be cleared prematurely. The flag needs to be cleared when
     the last reference of the inode is dropped and that happens in the
     inode's drop_inode() callback handler.

  Cleanups:

   - Consolidate the creation of a tracefs_inode for an eventfs_inode

     A tracefs_inode is created for both files and directories of the
     eventfs system. It is open coded. Instead, consolidate it into a
     single eventfs_get_inode() function call.

   - Remove the eventfs getattr and permission callbacks.

     The permissions for the eventfs files and directories are updated
     when the inodes are created, on remount, and when the user sets
     them (via setattr). The inodes hold the current permissions so
     there is no need to have custom getattr or permissions callbacks as
     they will more likely cause them to be incorrect. The inode's
     permissions are updated when they should be updated. Remove the
     getattr and permissions inode callbacks.

   - Do not update eventfs_inode attributes on creation of inodes.

     The eventfs_inodes attribute field is used to store the permissions
     of the directories and files for when their corresponding inodes
     are freed and are created again. But when the creation of the
     inodes happen, the eventfs_inode attributes are recalculated. The
     recalculation should only happen when the permissions change for a
     given file or directory. Currently, the attribute changes are just
     being set to their current files so this is not a bug, but it's
     unnecessary and error prone. Stop doing that.

   - The events directory inode is created once when the events
     directory is created and deleted when it is deleted. It is now
     updated on remount and when the user changes the permissions.
     There's no need to use the eventfs_inode of the events directory to
     store the events directory permissions. But using it to store the
     default permissions for the files within the directory that have
     not been updated by the user can simplify the code"

* tag 'trace-tracefs-v6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  eventfs: Do not use attributes for events directory
  eventfs: Cleanup permissions in creation of inodes
  eventfs: Remove getattr and permission callbacks
  eventfs: Consolidate the eventfs_inode update in eventfs_get_inode()
  tracefs: Clear EVENT_INODE flag in tracefs_drop_inode()
  eventfs: Update all the eventfs_inodes from the events descriptor
  tracefs: Update inode permissions on remount
  eventfs: Keep the directories from having the same inode number as files

fs/tracefs/inode.c

@@ -373,12 +373,21 @@ static int tracefs_apply_options(struct super_block *sb, bool remount)
 
 		rcu_read_lock();
 		list_for_each_entry_rcu(ti, &tracefs_inodes, list) {
-			if (update_uid)
+			if (update_uid) {
 				ti->flags &= ~TRACEFS_UID_PERM_SET;
+				ti->vfs_inode.i_uid = fsi->uid;
+			}
 
-			if (update_gid)
+			if (update_gid) {
 				ti->flags &= ~TRACEFS_GID_PERM_SET;
-
+				ti->vfs_inode.i_gid = fsi->gid;
+			}
+
+			/*
+			 * Note, the above ti->vfs_inode updates are
+			 * used in eventfs_remount() so they must come
+			 * before calling it.
+			 */
 			if (ti->flags & TRACEFS_EVENT_INODE)
 				eventfs_remount(ti, update_uid, update_gid);
 		}
@@ -417,10 +426,26 @@ static int tracefs_show_options(struct seq_file *m, struct dentry *root)
 	return 0;
 }
 
+static int tracefs_drop_inode(struct inode *inode)
+{
+	struct tracefs_inode *ti = get_tracefs(inode);
+
+	/*
+	 * This inode is being freed and cannot be used for
+	 * eventfs. Clear the flag so that it doesn't call into
+	 * eventfs during the remount flag updates. The eventfs_inode
+	 * gets freed after an RCU cycle, so the content will still
+	 * be safe if the iteration is going on now.
+	 */
+	ti->flags &= ~TRACEFS_EVENT_INODE;
+
+	return 1;
+}
+
 static const struct super_operations tracefs_super_operations = {
 	.alloc_inode    = tracefs_alloc_inode,
 	.free_inode     = tracefs_free_inode,
-	.drop_inode     = generic_delete_inode,
+	.drop_inode     = tracefs_drop_inode,
 	.statfs		= simple_statfs,
 	.show_options	= tracefs_show_options,
 };
@@ -446,22 +471,7 @@ static int tracefs_d_revalidate(struct dentry *dentry, unsigned int flags)
 	return !(ei && ei->is_freed);
 }
 
-static void tracefs_d_iput(struct dentry *dentry, struct inode *inode)
-{
-	struct tracefs_inode *ti = get_tracefs(inode);
-
-	/*
-	 * This inode is being freed and cannot be used for
-	 * eventfs. Clear the flag so that it doesn't call into
-	 * eventfs during the remount flag updates. The eventfs_inode
-	 * gets freed after an RCU cycle, so the content will still
-	 * be safe if the iteration is going on now.
-	 */
-	ti->flags &= ~TRACEFS_EVENT_INODE;
-}
-
 static const struct dentry_operations tracefs_dentry_operations = {
-	.d_iput = tracefs_d_iput,
 	.d_revalidate = tracefs_d_revalidate,
 	.d_release = tracefs_d_release,
 };