linux/fs/notify/inode_mark.c
Linus Torvalds 7d9071a095 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs updates from Al Viro:
 "In this one:

   - d_move fixes (Eric Biederman)

   - UFS fixes (me; locking is mostly sane now, a bunch of bugs in error
     handling ought to be fixed)

   - switch of sb_writers to percpu rwsem (Oleg Nesterov)

   - superblock scalability (Josef Bacik and Dave Chinner)

   - swapon(2) race fix (Hugh Dickins)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (65 commits)
  vfs: Test for and handle paths that are unreachable from their mnt_root
  dcache: Reduce the scope of i_lock in d_splice_alias
  dcache: Handle escaped paths in prepend_path
  mm: fix potential data race in SyS_swapon
  inode: don't softlockup when evicting inodes
  inode: rename i_wb_list to i_io_list
  sync: serialise per-superblock sync operations
  inode: convert inode_sb_list_lock to per-sb
  inode: add hlist_fake to avoid the inode hash lock in evict
  writeback: plug writeback at a high level
  change sb_writers to use percpu_rw_semaphore
  shift percpu_counter_destroy() into destroy_super_work()
  percpu-rwsem: kill CONFIG_PERCPU_RWSEM
  percpu-rwsem: introduce percpu_rwsem_release() and percpu_rwsem_acquire()
  percpu-rwsem: introduce percpu_down_read_trylock()
  document rwsem_release() in sb_wait_write()
  fix the broken lockdep logic in __sb_start_write()
  introduce __sb_writers_{acquired,release}() helpers
  ufs_inode_get{frag,block}(): get rid of 'phys' argument
  ufs_getfrag_block(): tidy up a bit
  ...
2015-09-05 20:34:28 -07:00

228 lines
6.3 KiB
C

/*
* 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/mutex.h>
#include <linux/spinlock.h>
#include <linux/atomic.h>
#include <linux/fsnotify_backend.h>
#include "fsnotify.h"
#include "../internal.h"
/*
* Recalculate the inode->i_fsnotify_mask, or the mask of all FS_* event types
* any notifier is interested in hearing for this inode.
*/
void fsnotify_recalc_inode_mask(struct inode *inode)
{
spin_lock(&inode->i_lock);
inode->i_fsnotify_mask = fsnotify_recalc_mask(&inode->i_fsnotify_marks);
spin_unlock(&inode->i_lock);
__fsnotify_update_child_dentry_flags(inode);
}
void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark)
{
struct inode *inode = mark->inode;
BUG_ON(!mutex_is_locked(&mark->group->mark_mutex));
assert_spin_locked(&mark->lock);
spin_lock(&inode->i_lock);
hlist_del_init_rcu(&mark->obj_list);
mark->inode = NULL;
/*
* this mark is now off the inode->i_fsnotify_marks list and we
* hold the inode->i_lock, so this is the perfect time to update the
* inode->i_fsnotify_mask
*/
inode->i_fsnotify_mask = fsnotify_recalc_mask(&inode->i_fsnotify_marks);
spin_unlock(&inode->i_lock);
}
/*
* Given a group clear all of the inode marks associated with that group.
*/
void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group)
{
fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_INODE);
}
/*
* given a group and inode, 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_inode_mark(struct fsnotify_group *group,
struct inode *inode)
{
struct fsnotify_mark *mark;
spin_lock(&inode->i_lock);
mark = fsnotify_find_mark(&inode->i_fsnotify_marks, group);
spin_unlock(&inode->i_lock);
return mark;
}
/*
* If we are setting a mark mask on an inode mark we should pin the inode
* in memory.
*/
void fsnotify_set_inode_mark_mask_locked(struct fsnotify_mark *mark,
__u32 mask)
{
struct inode *inode;
assert_spin_locked(&mark->lock);
if (mask &&
mark->inode &&
!(mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED)) {
mark->flags |= FSNOTIFY_MARK_FLAG_OBJECT_PINNED;
inode = igrab(mark->inode);
/*
* we shouldn't be able to get here if the inode wasn't
* already safely held in memory. But bug in case it
* ever is wrong.
*/
BUG_ON(!inode);
}
}
/*
* Attach an initialized mark to a given inode.
* These marks may be used for the fsnotify backend to determine which
* event types should be delivered to which group and for which inodes. These
* marks are ordered according to priority, highest number first, and then by
* the group's location in memory.
*/
int fsnotify_add_inode_mark(struct fsnotify_mark *mark,
struct fsnotify_group *group, struct inode *inode,
int allow_dups)
{
int ret;
mark->flags |= FSNOTIFY_MARK_FLAG_INODE;
BUG_ON(!mutex_is_locked(&group->mark_mutex));
assert_spin_locked(&mark->lock);
spin_lock(&inode->i_lock);
mark->inode = inode;
ret = fsnotify_add_mark_list(&inode->i_fsnotify_marks, mark,
allow_dups);
inode->i_fsnotify_mask = fsnotify_recalc_mask(&inode->i_fsnotify_marks);
spin_unlock(&inode->i_lock);
return ret;
}
/**
* fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes.
* @sb: superblock being unmounted.
*
* Called during unmount with no locks held, so needs to be safe against
* concurrent modifiers. We temporarily drop sb->s_inode_list_lock and CAN block.
*/
void fsnotify_unmount_inodes(struct super_block *sb)
{
struct inode *inode, *next_i, *need_iput = NULL;
spin_lock(&sb->s_inode_list_lock);
list_for_each_entry_safe(inode, next_i, &sb->s_inodes, i_sb_list) {
struct inode *need_iput_tmp;
/*
* We cannot __iget() an inode in state I_FREEING,
* I_WILL_FREE, or I_NEW which is fine because by that point
* the inode cannot have any associated watches.
*/
spin_lock(&inode->i_lock);
if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) {
spin_unlock(&inode->i_lock);
continue;
}
/*
* If i_count is zero, the inode cannot have any watches and
* doing an __iget/iput with MS_ACTIVE clear would actually
* evict all inodes with zero i_count from icache which is
* unnecessarily violent and may in fact be illegal to do.
*/
if (!atomic_read(&inode->i_count)) {
spin_unlock(&inode->i_lock);
continue;
}
need_iput_tmp = need_iput;
need_iput = NULL;
/* In case fsnotify_inode_delete() drops a reference. */
if (inode != need_iput_tmp)
__iget(inode);
else
need_iput_tmp = NULL;
spin_unlock(&inode->i_lock);
/* In case the dropping of a reference would nuke next_i. */
while (&next_i->i_sb_list != &sb->s_inodes) {
spin_lock(&next_i->i_lock);
if (!(next_i->i_state & (I_FREEING | I_WILL_FREE)) &&
atomic_read(&next_i->i_count)) {
__iget(next_i);
need_iput = next_i;
spin_unlock(&next_i->i_lock);
break;
}
spin_unlock(&next_i->i_lock);
next_i = list_entry(next_i->i_sb_list.next,
struct inode, i_sb_list);
}
/*
* We can safely drop s_inode_list_lock here because either
* we actually hold references on both inode and next_i or
* end of list. Also no new inodes will be added since the
* umount has begun.
*/
spin_unlock(&sb->s_inode_list_lock);
if (need_iput_tmp)
iput(need_iput_tmp);
/* for each watch, send FS_UNMOUNT and then remove it */
fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
fsnotify_inode_delete(inode);
iput(inode);
spin_lock(&sb->s_inode_list_lock);
}
spin_unlock(&sb->s_inode_list_lock);
}