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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
*/
#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);
}
/**
* 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.
*/
static void fsnotify_unmount_inodes(struct super_block *sb)
{
struct inode *inode, *iput_inode = NULL;
spin_lock(&sb->s_inode_list_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
/*
* 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 SB_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;
}
__iget(inode);
spin_unlock(&inode->i_lock);
spin_unlock(&sb->s_inode_list_lock);
if (iput_inode)
iput(iput_inode);
/* 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 = inode;
spin_lock(&sb->s_inode_list_lock);
}
spin_unlock(&sb->s_inode_list_lock);
if (iput_inode)
iput(iput_inode);
/* Wait for outstanding inode references from connectors */
wait_var_event(&sb->s_fsnotify_inode_refs,
!atomic_long_read(&sb->s_fsnotify_inode_refs));
}
void fsnotify_sb_delete(struct super_block *sb)
{
fsnotify_unmount_inodes(sb);
fsnotify_clear_marks_by_sb(sb);
}
/*
* fsnotify_nameremove - a filename was removed from a directory
*
* This is mostly called under parent vfs inode lock so name and
* dentry->d_parent should be stable. However there are some corner cases where
* inode lock is not held. So to be on the safe side and be reselient to future
* callers and out of tree users of d_delete(), we do not assume that d_parent
* and d_name are stable and we use dget_parent() and
* take_dentry_name_snapshot() to grab stable references.
*/
void fsnotify_nameremove(struct dentry *dentry, int isdir)
{
struct dentry *parent;
struct name_snapshot name;
__u32 mask = FS_DELETE;
/* d_delete() of pseudo inode? (e.g. __ns_get_path() playing tricks) */
if (IS_ROOT(dentry))
return;
if (isdir)
mask |= FS_ISDIR;
parent = dget_parent(dentry);
/* Avoid unneeded take_dentry_name_snapshot() */
if (!(d_inode(parent)->i_fsnotify_mask & FS_DELETE) &&
!(dentry->d_sb->s_fsnotify_mask & FS_DELETE))
goto out_dput;
take_dentry_name_snapshot(&name, dentry);
fsnotify(d_inode(parent), mask, d_inode(dentry), FSNOTIFY_EVENT_INODE,
&name.name, 0);
release_dentry_name_snapshot(&name);
out_dput:
dput(parent);
}
EXPORT_SYMBOL(fsnotify_nameremove);
/*
* 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 */
hlist_for_each_entry(alias, &inode->i_dentry, d_u.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_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(const 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 & ALL_FSNOTIFY_EVENTS) {
struct name_snapshot name;
/* 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;
take_dentry_name_snapshot(&name, dentry);
if (path)
ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
&name.name, 0);
else
ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
&name.name, 0);
release_dentry_name_snapshot(&name);
}
dput(parent);
return ret;
}
EXPORT_SYMBOL_GPL(__fsnotify_parent);
static int send_to_group(struct inode *to_tell,
__u32 mask, const void *data,
int data_is, u32 cookie,
const struct qstr *file_name,
struct fsnotify_iter_info *iter_info)
{
struct fsnotify_group *group = NULL;
__u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS);
__u32 marks_mask = 0;
__u32 marks_ignored_mask = 0;
struct fsnotify_mark *mark;
int type;
if (WARN_ON(!iter_info->report_mask))
return 0;
/* clear ignored on inode modification */
if (mask & FS_MODIFY) {
fsnotify_foreach_obj_type(type) {
if (!fsnotify_iter_should_report_type(iter_info, type))
continue;
mark = iter_info->marks[type];
if (mark &&
!(mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
mark->ignored_mask = 0;
}
}
fsnotify_foreach_obj_type(type) {
if (!fsnotify_iter_should_report_type(iter_info, type))
continue;
mark = iter_info->marks[type];
/* does the object mark tell us to do something? */
if (mark) {
group = mark->group;
marks_mask |= mark->mask;
marks_ignored_mask |= mark->ignored_mask;
}
}
pr_debug("%s: group=%p to_tell=%p mask=%x marks_mask=%x marks_ignored_mask=%x"
" data=%p data_is=%d cookie=%d\n",
__func__, group, to_tell, mask, marks_mask, marks_ignored_mask,
data, data_is, cookie);
if (!(test_mask & marks_mask & ~marks_ignored_mask))
return 0;
return group->ops->handle_event(group, to_tell, mask, data, data_is,
file_name, cookie, iter_info);
}
static struct fsnotify_mark *fsnotify_first_mark(struct fsnotify_mark_connector **connp)
{
struct fsnotify_mark_connector *conn;
struct hlist_node *node = NULL;
conn = srcu_dereference(*connp, &fsnotify_mark_srcu);
if (conn)
node = srcu_dereference(conn->list.first, &fsnotify_mark_srcu);
return hlist_entry_safe(node, struct fsnotify_mark, obj_list);<
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