mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-11-01 17:08:10 +00:00
873feea09e
dcache_inode_lock can be replaced with per-inode locking. Use existing inode->i_lock for this. This is slightly non-trivial because we sometimes need to find the inode from the dentry, which requires d_inode to be stabilised (either with refcount or d_lock). Signed-off-by: Nick Piggin <npiggin@kernel.dk>
310 lines
9.3 KiB
C
310 lines
9.3 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/dcache.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/init.h>
|
|
#include <linux/module.h>
|
|
#include <linux/mount.h>
|
|
#include <linux/srcu.h>
|
|
|
|
#include <linux/fsnotify_backend.h>
|
|
#include "fsnotify.h"
|
|
|
|
/*
|
|
* Clear all of the marks on an inode when it is being evicted from core
|
|
*/
|
|
void __fsnotify_inode_delete(struct inode *inode)
|
|
{
|
|
fsnotify_clear_marks_by_inode(inode);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__fsnotify_inode_delete);
|
|
|
|
void __fsnotify_vfsmount_delete(struct vfsmount *mnt)
|
|
{
|
|
fsnotify_clear_marks_by_mount(mnt);
|
|
}
|
|
|
|
/*
|
|
* Given an inode, first check if we care what happens to our children. Inotify
|
|
* and dnotify both tell their parents about events. If we care about any event
|
|
* on a child we run all of our children and set a dentry flag saying that the
|
|
* parent cares. Thus when an event happens on a child it can quickly tell if
|
|
* if there is a need to find a parent and send the event to the parent.
|
|
*/
|
|
void __fsnotify_update_child_dentry_flags(struct inode *inode)
|
|
{
|
|
struct dentry *alias;
|
|
int watched;
|
|
|
|
if (!S_ISDIR(inode->i_mode))
|
|
return;
|
|
|
|
/* determine if the children should tell inode about their events */
|
|
watched = fsnotify_inode_watches_children(inode);
|
|
|
|
spin_lock(&inode->i_lock);
|
|
/* run all of the dentries associated with this inode. Since this is a
|
|
* directory, there damn well better only be one item on this list */
|
|
list_for_each_entry(alias, &inode->i_dentry, d_alias) {
|
|
struct dentry *child;
|
|
|
|
/* run all of the children of the original inode and fix their
|
|
* d_flags to indicate parental interest (their parent is the
|
|
* original inode) */
|
|
spin_lock(&alias->d_lock);
|
|
list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) {
|
|
if (!child->d_inode)
|
|
continue;
|
|
|
|
spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
|
|
if (watched)
|
|
child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
|
|
else
|
|
child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
|
|
spin_unlock(&child->d_lock);
|
|
}
|
|
spin_unlock(&alias->d_lock);
|
|
}
|
|
spin_unlock(&inode->i_lock);
|
|
}
|
|
|
|
/* Notify this dentry's parent about a child's events. */
|
|
int __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
|
|
{
|
|
struct dentry *parent;
|
|
struct inode *p_inode;
|
|
int ret = 0;
|
|
|
|
if (!dentry)
|
|
dentry = path->dentry;
|
|
|
|
if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
|
|
return 0;
|
|
|
|
parent = dget_parent(dentry);
|
|
p_inode = parent->d_inode;
|
|
|
|
if (unlikely(!fsnotify_inode_watches_children(p_inode)))
|
|
__fsnotify_update_child_dentry_flags(p_inode);
|
|
else if (p_inode->i_fsnotify_mask & mask) {
|
|
/* we are notifying a parent so come up with the new mask which
|
|
* specifies these are events which came from a child. */
|
|
mask |= FS_EVENT_ON_CHILD;
|
|
|
|
if (path)
|
|
ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
|
|
dentry->d_name.name, 0);
|
|
else
|
|
ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
|
|
dentry->d_name.name, 0);
|
|
}
|
|
|
|
dput(parent);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__fsnotify_parent);
|
|
|
|
static int send_to_group(struct inode *to_tell, struct vfsmount *mnt,
|
|
struct fsnotify_mark *inode_mark,
|
|
struct fsnotify_mark *vfsmount_mark,
|
|
__u32 mask, void *data,
|
|
int data_is, u32 cookie,
|
|
const unsigned char *file_name,
|
|
struct fsnotify_event **event)
|
|
{
|
|
struct fsnotify_group *group = NULL;
|
|
__u32 inode_test_mask = 0;
|
|
__u32 vfsmount_test_mask = 0;
|
|
|
|
if (unlikely(!inode_mark && !vfsmount_mark)) {
|
|
BUG();
|
|
return 0;
|
|
}
|
|
|
|
/* clear ignored on inode modification */
|
|
if (mask & FS_MODIFY) {
|
|
if (inode_mark &&
|
|
!(inode_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
|
|
inode_mark->ignored_mask = 0;
|
|
if (vfsmount_mark &&
|
|
!(vfsmount_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
|
|
vfsmount_mark->ignored_mask = 0;
|
|
}
|
|
|
|
/* does the inode mark tell us to do something? */
|
|
if (inode_mark) {
|
|
group = inode_mark->group;
|
|
inode_test_mask = (mask & ~FS_EVENT_ON_CHILD);
|
|
inode_test_mask &= inode_mark->mask;
|
|
inode_test_mask &= ~inode_mark->ignored_mask;
|
|
}
|
|
|
|
/* does the vfsmount_mark tell us to do something? */
|
|
if (vfsmount_mark) {
|
|
vfsmount_test_mask = (mask & ~FS_EVENT_ON_CHILD);
|
|
group = vfsmount_mark->group;
|
|
vfsmount_test_mask &= vfsmount_mark->mask;
|
|
vfsmount_test_mask &= ~vfsmount_mark->ignored_mask;
|
|
if (inode_mark)
|
|
vfsmount_test_mask &= ~inode_mark->ignored_mask;
|
|
}
|
|
|
|
pr_debug("%s: group=%p to_tell=%p mnt=%p mask=%x inode_mark=%p"
|
|
" inode_test_mask=%x vfsmount_mark=%p vfsmount_test_mask=%x"
|
|
" data=%p data_is=%d cookie=%d event=%p\n",
|
|
__func__, group, to_tell, mnt, mask, inode_mark,
|
|
inode_test_mask, vfsmount_mark, vfsmount_test_mask, data,
|
|
data_is, cookie, *event);
|
|
|
|
if (!inode_test_mask && !vfsmount_test_mask)
|
|
return 0;
|
|
|
|
if (group->ops->should_send_event(group, to_tell, inode_mark,
|
|
vfsmount_mark, mask, data,
|
|
data_is) == false)
|
|
return 0;
|
|
|
|
if (!*event) {
|
|
*event = fsnotify_create_event(to_tell, mask, data,
|
|
data_is, file_name,
|
|
cookie, GFP_KERNEL);
|
|
if (!*event)
|
|
return -ENOMEM;
|
|
}
|
|
return group->ops->handle_event(group, inode_mark, vfsmount_mark, *event);
|
|
}
|
|
|
|
/*
|
|
* This is the main call to fsnotify. The VFS calls into hook specific functions
|
|
* in linux/fsnotify.h. Those functions then in turn call here. Here will call
|
|
* out to all of the registered fsnotify_group. Those groups can then use the
|
|
* notification event in whatever means they feel necessary.
|
|
*/
|
|
int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
|
|
const unsigned char *file_name, u32 cookie)
|
|
{
|
|
struct hlist_node *inode_node = NULL, *vfsmount_node = NULL;
|
|
struct fsnotify_mark *inode_mark = NULL, *vfsmount_mark = NULL;
|
|
struct fsnotify_group *inode_group, *vfsmount_group;
|
|
struct fsnotify_event *event = NULL;
|
|
struct vfsmount *mnt;
|
|
int idx, ret = 0;
|
|
/* global tests shouldn't care about events on child only the specific event */
|
|
__u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
|
|
|
|
if (data_is == FSNOTIFY_EVENT_PATH)
|
|
mnt = ((struct path *)data)->mnt;
|
|
else
|
|
mnt = NULL;
|
|
|
|
/*
|
|
* if this is a modify event we may need to clear the ignored masks
|
|
* otherwise return if neither the inode nor the vfsmount care about
|
|
* this type of event.
|
|
*/
|
|
if (!(mask & FS_MODIFY) &&
|
|
!(test_mask & to_tell->i_fsnotify_mask) &&
|
|
!(mnt && test_mask & mnt->mnt_fsnotify_mask))
|
|
return 0;
|
|
|
|
idx = srcu_read_lock(&fsnotify_mark_srcu);
|
|
|
|
if ((mask & FS_MODIFY) ||
|
|
(test_mask & to_tell->i_fsnotify_mask))
|
|
inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first,
|
|
&fsnotify_mark_srcu);
|
|
|
|
if (mnt && ((mask & FS_MODIFY) ||
|
|
(test_mask & mnt->mnt_fsnotify_mask))) {
|
|
vfsmount_node = srcu_dereference(mnt->mnt_fsnotify_marks.first,
|
|
&fsnotify_mark_srcu);
|
|
inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first,
|
|
&fsnotify_mark_srcu);
|
|
}
|
|
|
|
while (inode_node || vfsmount_node) {
|
|
inode_group = vfsmount_group = NULL;
|
|
|
|
if (inode_node) {
|
|
inode_mark = hlist_entry(srcu_dereference(inode_node, &fsnotify_mark_srcu),
|
|
struct fsnotify_mark, i.i_list);
|
|
inode_group = inode_mark->group;
|
|
}
|
|
|
|
if (vfsmount_node) {
|
|
vfsmount_mark = hlist_entry(srcu_dereference(vfsmount_node, &fsnotify_mark_srcu),
|
|
struct fsnotify_mark, m.m_list);
|
|
vfsmount_group = vfsmount_mark->group;
|
|
}
|
|
|
|
if (inode_group > vfsmount_group) {
|
|
/* handle inode */
|
|
ret = send_to_group(to_tell, NULL, inode_mark, NULL, mask, data,
|
|
data_is, cookie, file_name, &event);
|
|
/* we didn't use the vfsmount_mark */
|
|
vfsmount_group = NULL;
|
|
} else if (vfsmount_group > inode_group) {
|
|
ret = send_to_group(to_tell, mnt, NULL, vfsmount_mark, mask, data,
|
|
data_is, cookie, file_name, &event);
|
|
inode_group = NULL;
|
|
} else {
|
|
ret = send_to_group(to_tell, mnt, inode_mark, vfsmount_mark,
|
|
mask, data, data_is, cookie, file_name,
|
|
&event);
|
|
}
|
|
|
|
if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS))
|
|
goto out;
|
|
|
|
if (inode_group)
|
|
inode_node = srcu_dereference(inode_node->next,
|
|
&fsnotify_mark_srcu);
|
|
if (vfsmount_group)
|
|
vfsmount_node = srcu_dereference(vfsmount_node->next,
|
|
&fsnotify_mark_srcu);
|
|
}
|
|
ret = 0;
|
|
out:
|
|
srcu_read_unlock(&fsnotify_mark_srcu, idx);
|
|
/*
|
|
* fsnotify_create_event() took a reference so the event can't be cleaned
|
|
* up while we are still trying to add it to lists, drop that one.
|
|
*/
|
|
if (event)
|
|
fsnotify_put_event(event);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(fsnotify);
|
|
|
|
static __init int fsnotify_init(void)
|
|
{
|
|
int ret;
|
|
|
|
BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23);
|
|
|
|
ret = init_srcu_struct(&fsnotify_mark_srcu);
|
|
if (ret)
|
|
panic("initializing fsnotify_mark_srcu");
|
|
|
|
return 0;
|
|
}
|
|
core_initcall(fsnotify_init);
|