/* * 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/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->priority < lmark->group->priority) continue; if ((mark->group->priority == lmark->group->priority) && (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; }