80 строки
2.5 KiB
C
80 строки
2.5 KiB
C
/*
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* Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; see the file COPYING. If not, write to
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* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/dcache.h>
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/srcu.h>
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#include <linux/fsnotify_backend.h>
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#include "fsnotify.h"
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/*
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* This is the main call to fsnotify. The VFS calls into hook specific functions
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* in linux/fsnotify.h. Those functions then in turn call here. Here will call
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* out to all of the registered fsnotify_group. Those groups can then use the
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* notification event in whatever means they feel necessary.
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*/
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void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is)
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{
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struct fsnotify_group *group;
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struct fsnotify_event *event = NULL;
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int idx;
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if (list_empty(&fsnotify_groups))
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return;
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if (!(mask & fsnotify_mask))
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return;
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/*
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* SRCU!! the groups list is very very much read only and the path is
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* very hot. The VAST majority of events are not going to need to do
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* anything other than walk the list so it's crazy to pre-allocate.
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*/
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idx = srcu_read_lock(&fsnotify_grp_srcu);
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list_for_each_entry_rcu(group, &fsnotify_groups, group_list) {
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if (mask & group->mask) {
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if (!event) {
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event = fsnotify_create_event(to_tell, mask, data, data_is);
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/* shit, we OOM'd and now we can't tell, maybe
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* someday someone else will want to do something
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* here */
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if (!event)
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break;
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}
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group->ops->handle_event(group, event);
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}
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}
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srcu_read_unlock(&fsnotify_grp_srcu, idx);
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/*
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* fsnotify_create_event() took a reference so the event can't be cleaned
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* up while we are still trying to add it to lists, drop that one.
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*/
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if (event)
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fsnotify_put_event(event);
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}
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EXPORT_SYMBOL_GPL(fsnotify);
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static __init int fsnotify_init(void)
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{
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return init_srcu_struct(&fsnotify_grp_srcu);
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}
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subsys_initcall(fsnotify_init);
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