linux/fs/notify/fsnotify.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Copyright (C) 2008 Red Hat, Inc., Eric Paris <[email protected]>
 */

#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)
{ … }
EXPORT_SYMBOL_GPL(…);

void __fsnotify_vfsmount_delete(struct vfsmount *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)
{ … }

void fsnotify_sb_delete(struct super_block *sb)
{ … }

void fsnotify_sb_free(struct super_block *sb)
{ … }

/*
 * 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 there is a need to find a parent and send the event to the parent.
 */
void fsnotify_set_children_dentry_flags(struct inode *inode)
{ … }

/*
 * Lazily clear false positive PARENT_WATCHED flag for child whose parent had
 * stopped watching children.
 */
static void fsnotify_clear_child_dentry_flag(struct inode *pinode,
					     struct dentry *dentry)
{ … }

/* Are inode/sb/mount interested in parent and name info with this event? */
static bool fsnotify_event_needs_parent(struct inode *inode, __u32 mnt_mask,
					__u32 mask)
{ … }

/* Are there any inode/mount/sb objects that are interested in this event? */
static inline bool fsnotify_object_watched(struct inode *inode, __u32 mnt_mask,
					   __u32 mask)
{ … }

/*
 * Notify this dentry's parent about a child's events with child name info
 * if parent is watching or if inode/sb/mount are interested in events with
 * parent and name info.
 *
 * Notify only the child without name info if parent is not watching and
 * inode/sb/mount are not interested in events with parent and name info.
 */
int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data,
		      int data_type)
{ … }
EXPORT_SYMBOL_GPL(…);

static int fsnotify_handle_inode_event(struct fsnotify_group *group,
				       struct fsnotify_mark *inode_mark,
				       u32 mask, const void *data, int data_type,
				       struct inode *dir, const struct qstr *name,
				       u32 cookie)
{ … }

static int fsnotify_handle_event(struct fsnotify_group *group, __u32 mask,
				 const void *data, int data_type,
				 struct inode *dir, const struct qstr *name,
				 u32 cookie, struct fsnotify_iter_info *iter_info)
{ … }

static int send_to_group(__u32 mask, const void *data, int data_type,
			 struct inode *dir, const struct qstr *file_name,
			 u32 cookie, struct fsnotify_iter_info *iter_info)
{ … }

static struct fsnotify_mark *fsnotify_first_mark(struct fsnotify_mark_connector **connp)
{ … }

static struct fsnotify_mark *fsnotify_next_mark(struct fsnotify_mark *mark)
{ … }

/*
 * iter_info is a multi head priority queue of marks.
 * Pick a subset of marks from queue heads, all with the same group
 * and set the report_mask to a subset of the selected marks.
 * Returns false if there are no more groups to iterate.
 */
static bool fsnotify_iter_select_report_types(
		struct fsnotify_iter_info *iter_info)
{ … }

/*
 * Pop from iter_info multi head queue, the marks that belong to the group of
 * current iteration step.
 */
static void fsnotify_iter_next(struct fsnotify_iter_info *iter_info)
{ … }

/*
 * fsnotify - 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.
 *
 * @mask:	event type and flags
 * @data:	object that event happened on
 * @data_type:	type of object for fanotify_data_XXX() accessors
 * @dir:	optional directory associated with event -
 *		if @file_name is not NULL, this is the directory that
 *		@file_name is relative to
 * @file_name:	optional file name associated with event
 * @inode:	optional inode associated with event -
 *		If @dir and @inode are both non-NULL, event may be
 *		reported to both.
 * @cookie:	inotify rename cookie
 */
int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,
	     const struct qstr *file_name, struct inode *inode, u32 cookie)
{ … }
EXPORT_SYMBOL_GPL(…);

static __init int fsnotify_init(void)
{ … }
core_initcall(fsnotify_init);