fs/xfs/xfs_hooks.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (c) 2022-2024 Oracle.  All Rights Reserved.
   4  * Author: Darrick J. Wong <djwong@kernel.org>
   5  */
   6 #include "xfs.h"
   7 #include "xfs_fs.h"
   8 #include "xfs_shared.h"
   9 #include "xfs_format.h"
  10 #include "xfs_trans_resv.h"
  11 #include "xfs_mount.h"
  12 #include "xfs_ag.h"
  13 #include "xfs_trace.h"
  14
  15 /* Initialize a notifier chain. */
  16 void
  17 xfs_hooks_init(
  18         struct xfs_hooks        *chain)
  19 {
  20         BLOCKING_INIT_NOTIFIER_HEAD(&chain->head);
  21 }
  22
  23 /* Make it so a function gets called whenever we hit a certain hook point. */
  24 int
  25 xfs_hooks_add(
  26         struct xfs_hooks        *chain,
  27         struct xfs_hook         *hook)
  28 {
  29         ASSERT(hook->nb.notifier_call != NULL);
  30         BUILD_BUG_ON(offsetof(struct xfs_hook, nb) != 0);
  31
  32         return blocking_notifier_chain_register(&chain->head, &hook->nb);
  33 }
  34
  35 /* Remove a previously installed hook. */
  36 void
  37 xfs_hooks_del(
  38         struct xfs_hooks        *chain,
  39         struct xfs_hook         *hook)
  40 {
  41         blocking_notifier_chain_unregister(&chain->head, &hook->nb);
  42 }
  43
  44 /* Call a hook.  Returns the NOTIFY_* value returned by the last hook. */
  45 int
  46 xfs_hooks_call(
  47         struct xfs_hooks        *chain,
  48         unsigned long           val,
  49         void                    *priv)
  50 {
  51         return blocking_notifier_call_chain(&chain->head, val, priv);
  52 }