a4c6e9961f
In preparation for srcu locking use all _rcu appropiete functions for mark list addition, removal, and traversal. The operations are still done under a spinlock at the end of this patch. Signed-off-by: Eric Paris <eparis@redhat.com>
187 lines
5 KiB
C
187 lines
5 KiB
C
/*
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* Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; see the file COPYING. If not, write to
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* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/mount.h>
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#include <linux/mutex.h>
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#include <linux/spinlock.h>
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#include <linux/writeback.h> /* for inode_lock */
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#include <asm/atomic.h>
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#include <linux/fsnotify_backend.h>
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#include "fsnotify.h"
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void fsnotify_clear_marks_by_mount(struct vfsmount *mnt)
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{
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struct fsnotify_mark *mark, *lmark;
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struct hlist_node *pos, *n;
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LIST_HEAD(free_list);
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spin_lock(&mnt->mnt_root->d_lock);
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hlist_for_each_entry_safe(mark, pos, n, &mnt->mnt_fsnotify_marks, m.m_list) {
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list_add(&mark->m.free_m_list, &free_list);
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hlist_del_init_rcu(&mark->m.m_list);
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fsnotify_get_mark(mark);
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}
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spin_unlock(&mnt->mnt_root->d_lock);
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list_for_each_entry_safe(mark, lmark, &free_list, m.free_m_list) {
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fsnotify_destroy_mark(mark);
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fsnotify_put_mark(mark);
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}
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}
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void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group)
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{
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fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_VFSMOUNT);
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}
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/*
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* Recalculate the mask of events relevant to a given vfsmount locked.
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*/
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static void fsnotify_recalc_vfsmount_mask_locked(struct vfsmount *mnt)
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{
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struct fsnotify_mark *mark;
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struct hlist_node *pos;
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__u32 new_mask = 0;
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assert_spin_locked(&mnt->mnt_root->d_lock);
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hlist_for_each_entry(mark, pos, &mnt->mnt_fsnotify_marks, m.m_list)
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new_mask |= mark->mask;
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mnt->mnt_fsnotify_mask = new_mask;
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}
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/*
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* Recalculate the mnt->mnt_fsnotify_mask, or the mask of all FS_* event types
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* any notifier is interested in hearing for this mount point
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*/
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void fsnotify_recalc_vfsmount_mask(struct vfsmount *mnt)
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{
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spin_lock(&mnt->mnt_root->d_lock);
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fsnotify_recalc_vfsmount_mask_locked(mnt);
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spin_unlock(&mnt->mnt_root->d_lock);
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}
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void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark)
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{
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struct vfsmount *mnt = mark->m.mnt;
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assert_spin_locked(&mark->lock);
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assert_spin_locked(&mark->group->mark_lock);
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spin_lock(&mnt->mnt_root->d_lock);
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hlist_del_init_rcu(&mark->m.m_list);
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mark->m.mnt = NULL;
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fsnotify_recalc_vfsmount_mask_locked(mnt);
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spin_unlock(&mnt->mnt_root->d_lock);
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}
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static struct fsnotify_mark *fsnotify_find_vfsmount_mark_locked(struct fsnotify_group *group,
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struct vfsmount *mnt)
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{
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struct fsnotify_mark *mark;
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struct hlist_node *pos;
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assert_spin_locked(&mnt->mnt_root->d_lock);
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hlist_for_each_entry(mark, pos, &mnt->mnt_fsnotify_marks, m.m_list) {
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if (mark->group == group) {
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fsnotify_get_mark(mark);
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return mark;
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}
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}
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return NULL;
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}
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/*
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* given a group and vfsmount, find the mark associated with that combination.
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* if found take a reference to that mark and return it, else return NULL
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*/
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struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group,
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struct vfsmount *mnt)
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{
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struct fsnotify_mark *mark;
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spin_lock(&mnt->mnt_root->d_lock);
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mark = fsnotify_find_vfsmount_mark_locked(group, mnt);
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spin_unlock(&mnt->mnt_root->d_lock);
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return mark;
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}
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/*
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* Attach an initialized mark to a given group and vfsmount.
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* These marks may be used for the fsnotify backend to determine which
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* event types should be delivered to which groups.
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*/
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int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark,
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struct fsnotify_group *group, struct vfsmount *mnt,
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int allow_dups)
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{
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struct fsnotify_mark *lmark;
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struct hlist_node *node, *last = NULL;
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int ret = 0;
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mark->flags = FSNOTIFY_MARK_FLAG_VFSMOUNT;
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assert_spin_locked(&mark->lock);
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assert_spin_locked(&group->mark_lock);
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spin_lock(&mnt->mnt_root->d_lock);
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mark->m.mnt = mnt;
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/* is mark the first mark? */
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if (hlist_empty(&mnt->mnt_fsnotify_marks)) {
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hlist_add_head_rcu(&mark->m.m_list, &mnt->mnt_fsnotify_marks);
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goto out;
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}
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/* should mark be in the middle of the current list? */
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hlist_for_each_entry(lmark, node, &mnt->mnt_fsnotify_marks, m.m_list) {
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last = node;
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if ((lmark->group == group) && !allow_dups) {
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ret = -EEXIST;
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goto out;
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}
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if (mark->group < lmark->group)
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continue;
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hlist_add_before_rcu(&mark->m.m_list, &lmark->m.m_list);
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goto out;
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}
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BUG_ON(last == NULL);
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/* mark should be the last entry. last is the current last entry */
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hlist_add_after_rcu(last, &mark->m.m_list);
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out:
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fsnotify_recalc_vfsmount_mask_locked(mnt);
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spin_unlock(&mnt->mnt_root->d_lock);
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return ret;
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}
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