1/* 2 * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com> 3 * 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) 7 * any later version. 8 * 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. 13 * 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. 17 */ 18 19#include <linux/fs.h> 20#include <linux/init.h> 21#include <linux/kernel.h> 22#include <linux/module.h> 23#include <linux/mount.h> 24#include <linux/mutex.h> 25#include <linux/spinlock.h> 26 27#include <linux/atomic.h> 28 29#include <linux/fsnotify_backend.h> 30#include "fsnotify.h" 31 32void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group) 33{ 34 fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_VFSMOUNT); 35} 36 37/* 38 * Recalculate the mnt->mnt_fsnotify_mask, or the mask of all FS_* event types 39 * any notifier is interested in hearing for this mount point 40 */ 41void fsnotify_recalc_vfsmount_mask(struct vfsmount *mnt) 42{ 43 struct mount *m = real_mount(mnt); 44 45 spin_lock(&mnt->mnt_root->d_lock); 46 m->mnt_fsnotify_mask = fsnotify_recalc_mask(&m->mnt_fsnotify_marks); 47 spin_unlock(&mnt->mnt_root->d_lock); 48} 49 50void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark) 51{ 52 struct vfsmount *mnt = mark->mnt; 53 struct mount *m = real_mount(mnt); 54 55 BUG_ON(!mutex_is_locked(&mark->group->mark_mutex)); 56 assert_spin_locked(&mark->lock); 57 58 spin_lock(&mnt->mnt_root->d_lock); 59 60 hlist_del_init_rcu(&mark->obj_list); 61 mark->mnt = NULL; 62 63 m->mnt_fsnotify_mask = fsnotify_recalc_mask(&m->mnt_fsnotify_marks); 64 spin_unlock(&mnt->mnt_root->d_lock); 65} 66 67/* 68 * given a group and vfsmount, find the mark associated with that combination. 69 * if found take a reference to that mark and return it, else return NULL 70 */ 71struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group, 72 struct vfsmount *mnt) 73{ 74 struct mount *m = real_mount(mnt); 75 struct fsnotify_mark *mark; 76 77 spin_lock(&mnt->mnt_root->d_lock); 78 mark = fsnotify_find_mark(&m->mnt_fsnotify_marks, group); 79 spin_unlock(&mnt->mnt_root->d_lock); 80 81 return mark; 82} 83 84/* 85 * Attach an initialized mark to a given group and vfsmount. 86 * These marks may be used for the fsnotify backend to determine which 87 * event types should be delivered to which groups. 88 */ 89int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark, 90 struct fsnotify_group *group, struct vfsmount *mnt, 91 int allow_dups) 92{ 93 struct mount *m = real_mount(mnt); 94 int ret; 95 96 mark->flags |= FSNOTIFY_MARK_FLAG_VFSMOUNT; 97 98 BUG_ON(!mutex_is_locked(&group->mark_mutex)); 99 assert_spin_locked(&mark->lock); 100 101 spin_lock(&mnt->mnt_root->d_lock); 102 mark->mnt = mnt; 103 ret = fsnotify_add_mark_list(&m->mnt_fsnotify_marks, mark, allow_dups); 104 m->mnt_fsnotify_mask = fsnotify_recalc_mask(&m->mnt_fsnotify_marks); 105 spin_unlock(&mnt->mnt_root->d_lock); 106 107 return ret; 108} 109