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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /fs/notify/group.c | |
parent | Initial commit. (diff) | |
download | linux-430c2fc249ea5c0536abd21c23382884005c9093.tar.xz linux-430c2fc249ea5c0536abd21c23382884005c9093.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/notify/group.c')
-rw-r--r-- | fs/notify/group.c | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/fs/notify/group.c b/fs/notify/group.c new file mode 100644 index 000000000..a4a4b1c64 --- /dev/null +++ b/fs/notify/group.c @@ -0,0 +1,149 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com> + */ + +#include <linux/list.h> +#include <linux/mutex.h> +#include <linux/slab.h> +#include <linux/srcu.h> +#include <linux/rculist.h> +#include <linux/wait.h> +#include <linux/memcontrol.h> + +#include <linux/fsnotify_backend.h> +#include "fsnotify.h" + +#include <linux/atomic.h> + +/* + * Final freeing of a 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 + * hold a ref to the group. + */ +void fsnotify_destroy_group(struct fsnotify_group *group) +{ + /* + * 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_ALL_TYPES_MASK); + + /* + * 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->overflow_event); + + fsnotify_put_group(group); +} + +/* + * Get reference to a group. + */ +void fsnotify_get_group(struct fsnotify_group *group) +{ + refcount_inc(&group->refcnt); +} + +/* + * Drop a reference to a group. Free it if it's through. + */ +void fsnotify_put_group(struct fsnotify_group *group) +{ + 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) +{ + struct fsnotify_group *group; + + group = kzalloc(sizeof(struct fsnotify_group), GFP_KERNEL); + if (!group) + return ERR_PTR(-ENOMEM); + + /* set to 0 when there a no external references to this group */ + refcount_set(&group->refcnt, 1); + atomic_set(&group->num_marks, 0); + atomic_set(&group->user_waits, 0); + + spin_lock_init(&group->notification_lock); + INIT_LIST_HEAD(&group->notification_list); + init_waitqueue_head(&group->notification_waitq); + group->max_events = UINT_MAX; + + mutex_init(&group->mark_mutex); + INIT_LIST_HEAD(&group->marks_list); + + group->ops = ops; + + return group; +} +EXPORT_SYMBOL_GPL(fsnotify_alloc_group); + +int fsnotify_fasync(int fd, struct file *file, int on) +{ + struct fsnotify_group *group = file->private_data; + + return fasync_helper(fd, file, on, &group->fsn_fa) >= 0 ? 0 : -EIO; +} |