forked from Minki/linux
3be25f49b9
This patch creates a way for fsnotify groups to attach marks to inodes. These marks have little meaning to the generic fsnotify infrastructure and thus their meaning should be interpreted by the group that attached them to the inode's list. dnotify and inotify will make use of these markings to indicate which inodes are of interest to their respective groups. But this implementation has the useful property that in the future other listeners could actually use the marks for the exact opposite reason, aka to indicate which inodes it had NO interest in. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de>
93 lines
2.8 KiB
C
93 lines
2.8 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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* Clear all of the marks on an inode when it is being evicted from core
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*/
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void __fsnotify_inode_delete(struct inode *inode)
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{
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fsnotify_clear_marks_by_inode(inode);
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}
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EXPORT_SYMBOL_GPL(__fsnotify_inode_delete);
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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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if (!(mask & to_tell->i_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 (!group->ops->should_send_event(group, to_tell, mask))
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continue;
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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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