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/*
* 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/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mount.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/writeback.h> /* for inode_lock */
#include <asm/atomic.h>
#include <linux/fsnotify_backend.h>
#include "fsnotify.h"
void fsnotify_clear_marks_by_mount(struct vfsmount *mnt)
{
struct fsnotify_mark *mark, *lmark;
struct hlist_node *pos, *n;
LIST_HEAD(free_list);
spin_lock(&mnt->mnt_root->d_lock);
hlist_for_each_entry_safe(mark, pos, n, &mnt->mnt_fsnotify_marks, m.m_list) {
list_add(&mark->m.free_m_list, &free_list);
hlist_del_init_rcu(&mark->m.m_list);
fsnotify_get_mark(mark);
}
spin_unlock(&mnt->mnt_root->d_lock);
list_for_each_entry_safe(mark, lmark, &free_list, m.free_m_list) {
fsnotify_destroy_mark(mark);
fsnotify_put_mark(mark);
}
}
void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group)
{
fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_VFSMOUNT);
}
/*
* Recalculate the mask of events relevant to a given vfsmount locked.
*/
static void fsnotify_recalc_vfsmount_mask_locked(struct vfsmount *mnt)
{
struct fsnotify_mark *mark;
struct hlist_node *pos;
__u32 new_mask = 0;
assert_spin_locked(&mnt->mnt_root->d_lock);
hlist_for_each_entry(mark, pos, &mnt->mnt_fsnotify_marks, m.m_list)
new_mask |= mark->mask;
mnt->mnt_fsnotify_mask = new_mask;
}
/*
* Recalculate the mnt->mnt_fsnotify_mask, or the mask of all FS_* event types
* any notifier is interested in hearing for this mount point
*/
void fsnotify_recalc_vfsmount_mask(struct vfsmount *mnt)
{
spin_lock(&mnt->mnt_root->d_lock);
fsnotify_recalc_vfsmount_mask_locked(mnt);
spin_unlock(&mnt->mnt_root->d_lock);
}
void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark)
{
struct vfsmount *mnt = mark->m.mnt;
assert_spin_locked(&mark->lock);
assert_spin_locked(&mark->group->mark_lock);
spin_lock(&mnt->mnt_root->d_lock);
hlist_del_init_rcu(&mark->m.m_list);
mark->m.mnt = NULL;
fsnotify_recalc_vfsmount_mask_locked(mnt);
spin_unlock(&mnt->mnt_root->d_lock);
}
static struct fsnotify_mark *fsnotify_find_vfsmount_mark_locked(struct fsnotify_group *group,
struct vfsmount *mnt)
{
struct fsnotify_mark *mark;
struct hlist_node *pos;
assert_spin_locked(&mnt->mnt_root->d_lock);
hlist_for_each_entry(mark, pos, &mnt->mnt_fsnotify_marks, m.m_list) {
if (mark->group == group) {
fsnotify_get_mark(mark);
return mark;
}
}
return NULL;
}
/*
* given a group and vfsmount, find the mark associated with that combination.
* if found take a reference to that mark and return it, else return NULL
*/
struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group,
struct vfsmount *mnt)
{
struct fsnotify_mark *mark;
spin_lock(&mnt->mnt_root->d_lock);
mark = fsnotify_find_vfsmount_mark_locked(group, mnt);
spin_unlock(&mnt->mnt_root->d_lock);
return mark;
}
/*
* Attach an initialized mark to a given group and vfsmount.
* These marks may be used for the fsnotify backend to determine which
* event types should be delivered to which groups.
*/
int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark,
struct fsnotify_group *group, struct vfsmount *mnt,
int allow_dups)
{
struct fsnotify_mark *lmark;
struct hlist_node *node, *last = NULL;
int ret = 0;
mark->flags |= FSNOTIFY_MARK_FLAG_VFSMOUNT;
assert_spin_locked(&mark->lock);
assert_spin_locked(&group->mark_lock);
spin_lock(&mnt->mnt_root->d_lock);
mark->m.mnt = mnt;
/* is mark the first mark? */
if (hlist_empty(&mnt->mnt_fsnotify_marks)) {
hlist_add_head_rcu(&mark->m.m_list, &mnt->mnt_fsnotify_marks);
goto out;
}
/* should mark be in the middle of the current list? */
hlist_for_each_entry(lmark, node, &mnt->mnt_fsnotify_marks, m.m_list) {
last = node;
if ((lmark->group == group) && !allow_dups) {
ret = -EEXIST;
goto out;
}
if (mark->group < lmark->group)
continue;
hlist_add_before_rcu(&mark->m.m_list, &lmark->m.m_list);
goto out;
}
BUG_ON(last == NULL);
/* mark should be the last entry. last is the current last entry */
hlist_add_after_rcu(last, &mark->m.m_list);
out:
fsnotify_recalc_vfsmount_mask_locked(mnt);
spin_unlock(&mnt->mnt_root->d_lock);
return ret;
}
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