2 * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2, or (at your option)
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; see the file COPYING. If not, write to
16 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
19 #include <linux/list.h>
20 #include <linux/mutex.h>
21 #include <linux/slab.h>
22 #include <linux/srcu.h>
23 #include <linux/rculist.h>
24 #include <linux/wait.h>
26 #include <linux/fsnotify_backend.h>
29 #include <linux/atomic.h>
32 * Final freeing of a group
34 static void fsnotify_final_destroy_group(struct fsnotify_group
*group
)
36 if (group
->ops
->free_group_priv
)
37 group
->ops
->free_group_priv(group
);
43 * Trying to get rid of a group. Remove all marks, flush all events and release
44 * the group reference.
45 * Note that another thread calling fsnotify_clear_marks_by_group() may still
46 * hold a ref to the group.
48 void fsnotify_destroy_group(struct fsnotify_group
*group
)
50 /* clear all inode marks for this group, attach them to destroy_list */
51 fsnotify_detach_group_marks(group
);
54 * Wait for fsnotify_mark_srcu period to end and free all marks in
57 fsnotify_mark_destroy_list();
60 * Since we have waited for fsnotify_mark_srcu in
61 * fsnotify_mark_destroy_list() there can be no outstanding event
62 * notification against this group. So clearing the notification queue
63 * of all events is reliable now.
65 fsnotify_flush_notify(group
);
68 * Destroy overflow event (we cannot use fsnotify_destroy_event() as
69 * that deliberately ignores overflow events.
71 if (group
->overflow_event
)
72 group
->ops
->free_event(group
->overflow_event
);
74 fsnotify_put_group(group
);
78 * Get reference to a group.
80 void fsnotify_get_group(struct fsnotify_group
*group
)
82 atomic_inc(&group
->refcnt
);
86 * Drop a reference to a group. Free it if it's through.
88 void fsnotify_put_group(struct fsnotify_group
*group
)
90 if (atomic_dec_and_test(&group
->refcnt
))
91 fsnotify_final_destroy_group(group
);
95 * Create a new fsnotify_group and hold a reference for the group returned.
97 struct fsnotify_group
*fsnotify_alloc_group(const struct fsnotify_ops
*ops
)
99 struct fsnotify_group
*group
;
101 group
= kzalloc(sizeof(struct fsnotify_group
), GFP_KERNEL
);
103 return ERR_PTR(-ENOMEM
);
105 /* set to 0 when there a no external references to this group */
106 atomic_set(&group
->refcnt
, 1);
107 atomic_set(&group
->num_marks
, 0);
109 mutex_init(&group
->notification_mutex
);
110 INIT_LIST_HEAD(&group
->notification_list
);
111 init_waitqueue_head(&group
->notification_waitq
);
112 group
->max_events
= UINT_MAX
;
114 mutex_init(&group
->mark_mutex
);
115 INIT_LIST_HEAD(&group
->marks_list
);
122 int fsnotify_fasync(int fd
, struct file
*file
, int on
)
124 struct fsnotify_group
*group
= file
->private_data
;
126 return fasync_helper(fd
, file
, on
, &group
->fsn_fa
) >= 0 ? 0 : -EIO
;
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