fs/notify/vfsmount_mark.c

   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 #include "../mount.h"
  32
  33 void fsnotify_clear_marks_by_mount(struct vfsmount *mnt)
  34 {
  35         struct fsnotify_mark *mark;
  36         struct hlist_node *n;
  37         struct mount *m = real_mount(mnt);
  38         LIST_HEAD(free_list);
  39
  40         spin_lock(&mnt->mnt_root->d_lock);
  41         hlist_for_each_entry_safe(mark, n, &m->mnt_fsnotify_marks, obj_list) {
  42                 list_add(&mark->free_list, &free_list);
  43                 hlist_del_init_rcu(&mark->obj_list);
  44                 fsnotify_get_mark(mark);
  45         }
  46         spin_unlock(&mnt->mnt_root->d_lock);
  47
  48         fsnotify_destroy_marks(&free_list);
  49 }
  50
  51 void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group)
  52 {
  53         fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_VFSMOUNT);
  54 }
  55
  56 /*
  57  * Recalculate the mnt->mnt_fsnotify_mask, or the mask of all FS_* event types
  58  * any notifier is interested in hearing for this mount point
  59  */
  60 void fsnotify_recalc_vfsmount_mask(struct vfsmount *mnt)
  61 {
  62         struct mount *m = real_mount(mnt);
  63
  64         spin_lock(&mnt->mnt_root->d_lock);
  65         m->mnt_fsnotify_mask = fsnotify_recalc_mask(&m->mnt_fsnotify_marks);
  66         spin_unlock(&mnt->mnt_root->d_lock);
  67 }
  68
  69 void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark)
  70 {
  71         struct vfsmount *mnt = mark->mnt;
  72         struct mount *m = real_mount(mnt);
  73
  74         BUG_ON(!mutex_is_locked(&mark->group->mark_mutex));
  75         assert_spin_locked(&mark->lock);
  76
  77         spin_lock(&mnt->mnt_root->d_lock);
  78
  79         hlist_del_init_rcu(&mark->obj_list);
  80         mark->mnt = NULL;
  81
  82         m->mnt_fsnotify_mask = fsnotify_recalc_mask(&m->mnt_fsnotify_marks);
  83         spin_unlock(&mnt->mnt_root->d_lock);
  84 }
  85
  86 /*
  87  * given a group and vfsmount, find the mark associated with that combination.
  88  * if found take a reference to that mark and return it, else return NULL
  89  */
  90 struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group,
  91                                                   struct vfsmount *mnt)
  92 {
  93         struct mount *m = real_mount(mnt);
  94         struct fsnotify_mark *mark;
  95
  96         spin_lock(&mnt->mnt_root->d_lock);
  97         mark = fsnotify_find_mark(&m->mnt_fsnotify_marks, group);
  98         spin_unlock(&mnt->mnt_root->d_lock);
  99
 100         return mark;
 101 }
 102
 103 /*
 104  * Attach an initialized mark to a given group and vfsmount.
 105  * These marks may be used for the fsnotify backend to determine which
 106  * event types should be delivered to which groups.
 107  */
 108 int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark,
 109                                struct fsnotify_group *group, struct vfsmount *mnt,
 110                                int allow_dups)
 111 {
 112         struct mount *m = real_mount(mnt);
 113         int ret;
 114
 115         mark->flags |= FSNOTIFY_MARK_FLAG_VFSMOUNT;
 116
 117         BUG_ON(!mutex_is_locked(&group->mark_mutex));
 118         assert_spin_locked(&mark->lock);
 119
 120         spin_lock(&mnt->mnt_root->d_lock);
 121         mark->mnt = mnt;
 122         ret = fsnotify_add_mark_list(&m->mnt_fsnotify_marks, mark, allow_dups);
 123         m->mnt_fsnotify_mask = fsnotify_recalc_mask(&m->mnt_fsnotify_marks);
 124         spin_unlock(&mnt->mnt_root->d_lock);
 125
 126         return ret;
 127 }