diff options
Diffstat (limited to 'fs/notify/vfsmount_mark.c')
| -rw-r--r-- | fs/notify/vfsmount_mark.c | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/fs/notify/vfsmount_mark.c b/fs/notify/vfsmount_mark.c new file mode 100644 index 00000000000..56772b578fb --- /dev/null +++ b/fs/notify/vfsmount_mark.c @@ -0,0 +1,187 @@ +/* + * 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; +} |