diff options
Diffstat (limited to 'fs/notify/group.c')
| -rw-r--r-- | fs/notify/group.c | 111 |
1 files changed, 80 insertions, 31 deletions
diff --git a/fs/notify/group.c b/fs/notify/group.c index bd2625bd88b4..18446b7b0d49 100644 --- a/fs/notify/group.c +++ b/fs/notify/group.c @@ -1,19 +1,6 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com> - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2, or (at your option) - * any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; see the file COPYING. If not, write to - * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ #include <linux/list.h> @@ -22,6 +9,7 @@ #include <linux/srcu.h> #include <linux/rculist.h> #include <linux/wait.h> +#include <linux/memcontrol.h> #include <linux/fsnotify_backend.h> #include "fsnotify.h" @@ -31,15 +19,29 @@ /* * Final freeing of a group */ -void fsnotify_final_destroy_group(struct fsnotify_group *group) +static void fsnotify_final_destroy_group(struct fsnotify_group *group) { if (group->ops->free_group_priv) group->ops->free_group_priv(group); + mem_cgroup_put(group->memcg); + mutex_destroy(&group->mark_mutex); + kfree(group); } /* + * Stop queueing new events for this group. Once this function returns + * fsnotify_add_event() will not add any new events to the group's queue. + */ +void fsnotify_group_stop_queueing(struct fsnotify_group *group) +{ + spin_lock(&group->notification_lock); + group->shutdown = true; + spin_unlock(&group->notification_lock); +} + +/* * Trying to get rid of a group. Remove all marks, flush all events and release * the group reference. * Note that another thread calling fsnotify_clear_marks_by_group() may still @@ -47,14 +49,47 @@ void fsnotify_final_destroy_group(struct fsnotify_group *group) */ void fsnotify_destroy_group(struct fsnotify_group *group) { - /* clear all inode marks for this group */ - fsnotify_clear_marks_by_group(group); - - synchronize_srcu(&fsnotify_mark_srcu); - - /* clear the notification queue of all events */ + /* + * Stop queueing new events. The code below is careful enough to not + * require this but fanotify needs to stop queuing events even before + * fsnotify_destroy_group() is called and this makes the other callers + * of fsnotify_destroy_group() to see the same behavior. + */ + fsnotify_group_stop_queueing(group); + + /* Clear all marks for this group and queue them for destruction */ + fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_TYPE_ANY); + + /* + * Some marks can still be pinned when waiting for response from + * userspace. Wait for those now. fsnotify_prepare_user_wait() will + * not succeed now so this wait is race-free. + */ + wait_event(group->notification_waitq, !atomic_read(&group->user_waits)); + + /* + * Wait until all marks get really destroyed. We could actually destroy + * them ourselves instead of waiting for worker to do it, however that + * would be racy as worker can already be processing some marks before + * we even entered fsnotify_destroy_group(). + */ + fsnotify_wait_marks_destroyed(); + + /* + * Since we have waited for fsnotify_mark_srcu in + * fsnotify_mark_destroy_list() there can be no outstanding event + * notification against this group. So clearing the notification queue + * of all events is reliable now. + */ fsnotify_flush_notify(group); + /* + * Destroy overflow event (we cannot use fsnotify_destroy_event() as + * that deliberately ignores overflow events. + */ + if (group->overflow_event) + group->ops->free_event(group, group->overflow_event); + fsnotify_put_group(group); } @@ -63,7 +98,7 @@ void fsnotify_destroy_group(struct fsnotify_group *group) */ void fsnotify_get_group(struct fsnotify_group *group) { - atomic_inc(&group->refcnt); + refcount_inc(&group->refcnt); } /* @@ -71,26 +106,26 @@ void fsnotify_get_group(struct fsnotify_group *group) */ void fsnotify_put_group(struct fsnotify_group *group) { - if (atomic_dec_and_test(&group->refcnt)) + if (refcount_dec_and_test(&group->refcnt)) fsnotify_final_destroy_group(group); } +EXPORT_SYMBOL_GPL(fsnotify_put_group); -/* - * Create a new fsnotify_group and hold a reference for the group returned. - */ -struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops) +static struct fsnotify_group *__fsnotify_alloc_group( + const struct fsnotify_ops *ops, + int flags, gfp_t gfp) { struct fsnotify_group *group; - group = kzalloc(sizeof(struct fsnotify_group), GFP_KERNEL); + group = kzalloc(sizeof(struct fsnotify_group), gfp); if (!group) return ERR_PTR(-ENOMEM); /* set to 0 when there a no external references to this group */ - atomic_set(&group->refcnt, 1); - atomic_set(&group->num_marks, 0); + refcount_set(&group->refcnt, 1); + atomic_set(&group->user_waits, 0); - mutex_init(&group->notification_mutex); + spin_lock_init(&group->notification_lock); INIT_LIST_HEAD(&group->notification_list); init_waitqueue_head(&group->notification_waitq); group->max_events = UINT_MAX; @@ -99,10 +134,24 @@ struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops) INIT_LIST_HEAD(&group->marks_list); group->ops = ops; + group->flags = flags; return group; } +/* + * Create a new fsnotify_group and hold a reference for the group returned. + */ +struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops, + int flags) +{ + gfp_t gfp = (flags & FSNOTIFY_GROUP_USER) ? GFP_KERNEL_ACCOUNT : + GFP_KERNEL; + + return __fsnotify_alloc_group(ops, flags, gfp); +} +EXPORT_SYMBOL_GPL(fsnotify_alloc_group); + int fsnotify_fasync(int fd, struct file *file, int on) { struct fsnotify_group *group = file->private_data; |