linux-next/include/linux/fsnotify.h
Amir Goldstein 5f02a87763 fsnotify: annotate directory entry modification events
"dirent" events are referring to events that modify directory entries,
such as create,delete,rename. Those events should always be reported
on a watched directory, regardless if FS_EVENT_ON_CHILD is set
on the watch mask.

fsnotify_nameremove() and fsnotify_move() were modified to no longer
set the FS_EVENT_ON_CHILD event bit. This is a semantic change to
align with the "dirent" event definition. It has no effect on any
existing backend, because dnotify, inotify and audit always requets the
child events and fanotify does not get the delete,rename events.

The fsnotify_dirent() helper is used instead of fsnotify_parent() to
report a dirent event to dentry->d_parent without FS_EVENT_ON_CHILD
and regardless if parent has the FS_EVENT_ON_CHILD bit set.

Unlike fsnotify_parent(), fsnotify_dirent() assumes that dentry->d_name
and dentry->d_parent are stable. For fsnotify_create()/fsnotify_mkdir(),
this assumption is abviously correct. For fsnotify_nameremove(), it is
less trivial, so we use dget_parent() and take_dentry_name_snapshot() to
grab stable references.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-06 15:11:59 +01:00

336 lines
8.4 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_FS_NOTIFY_H
#define _LINUX_FS_NOTIFY_H
/*
* include/linux/fsnotify.h - generic hooks for filesystem notification, to
* reduce in-source duplication from both dnotify and inotify.
*
* We don't compile any of this away in some complicated menagerie of ifdefs.
* Instead, we rely on the code inside to optimize away as needed.
*
* (C) Copyright 2005 Robert Love
*/
#include <linux/fsnotify_backend.h>
#include <linux/audit.h>
#include <linux/slab.h>
#include <linux/bug.h>
/*
* Notify this @dir inode about a change in the directory entry @dentry.
*
* Unlike fsnotify_parent(), the event will be reported regardless of the
* FS_EVENT_ON_CHILD mask on the parent inode.
*/
static inline int fsnotify_dirent(struct inode *dir, struct dentry *dentry,
__u32 mask)
{
return fsnotify(dir, mask, d_inode(dentry), FSNOTIFY_EVENT_INODE,
dentry->d_name.name, 0);
}
/* Notify this dentry's parent about a child's events. */
static inline int fsnotify_parent(const struct path *path,
struct dentry *dentry, __u32 mask)
{
if (!dentry)
dentry = path->dentry;
return __fsnotify_parent(path, dentry, mask);
}
/*
* Simple wrapper to consolidate calls fsnotify_parent()/fsnotify() when
* an event is on a path.
*/
static inline int fsnotify_path(struct inode *inode, const struct path *path,
__u32 mask)
{
int ret = fsnotify_parent(path, NULL, mask);
if (ret)
return ret;
return fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
}
/* Simple call site for access decisions */
static inline int fsnotify_perm(struct file *file, int mask)
{
int ret;
const struct path *path = &file->f_path;
struct inode *inode = file_inode(file);
__u32 fsnotify_mask = 0;
if (file->f_mode & FMODE_NONOTIFY)
return 0;
if (!(mask & (MAY_READ | MAY_OPEN)))
return 0;
if (mask & MAY_OPEN) {
fsnotify_mask = FS_OPEN_PERM;
if (file->f_flags & __FMODE_EXEC) {
ret = fsnotify_path(inode, path, FS_OPEN_EXEC_PERM);
if (ret)
return ret;
}
} else if (mask & MAY_READ) {
fsnotify_mask = FS_ACCESS_PERM;
}
return fsnotify_path(inode, path, fsnotify_mask);
}
/*
* fsnotify_link_count - inode's link count changed
*/
static inline void fsnotify_link_count(struct inode *inode)
{
fsnotify(inode, FS_ATTRIB, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
}
/*
* fsnotify_move - file old_name at old_dir was moved to new_name at new_dir
*/
static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
const unsigned char *old_name,
int isdir, struct inode *target, struct dentry *moved)
{
struct inode *source = moved->d_inode;
u32 fs_cookie = fsnotify_get_cookie();
__u32 old_dir_mask = FS_MOVED_FROM;
__u32 new_dir_mask = FS_MOVED_TO;
const unsigned char *new_name = moved->d_name.name;
if (old_dir == new_dir)
old_dir_mask |= FS_DN_RENAME;
if (isdir) {
old_dir_mask |= FS_ISDIR;
new_dir_mask |= FS_ISDIR;
}
fsnotify(old_dir, old_dir_mask, source, FSNOTIFY_EVENT_INODE, old_name,
fs_cookie);
fsnotify(new_dir, new_dir_mask, source, FSNOTIFY_EVENT_INODE, new_name,
fs_cookie);
if (target)
fsnotify_link_count(target);
if (source)
fsnotify(source, FS_MOVE_SELF, moved->d_inode, FSNOTIFY_EVENT_INODE, NULL, 0);
audit_inode_child(new_dir, moved, AUDIT_TYPE_CHILD_CREATE);
}
/*
* fsnotify_inode_delete - and inode is being evicted from cache, clean up is needed
*/
static inline void fsnotify_inode_delete(struct inode *inode)
{
__fsnotify_inode_delete(inode);
}
/*
* fsnotify_vfsmount_delete - a vfsmount is being destroyed, clean up is needed
*/
static inline void fsnotify_vfsmount_delete(struct vfsmount *mnt)
{
__fsnotify_vfsmount_delete(mnt);
}
/*
* 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.
*/
static inline 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);
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);
dput(parent);
}
/*
* fsnotify_inoderemove - an inode is going away
*/
static inline void fsnotify_inoderemove(struct inode *inode)
{
fsnotify(inode, FS_DELETE_SELF, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
__fsnotify_inode_delete(inode);
}
/*
* fsnotify_create - 'name' was linked in
*/
static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
{
audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
fsnotify_dirent(inode, dentry, FS_CREATE);
}
/*
* fsnotify_link - new hardlink in 'inode' directory
* Note: We have to pass also the linked inode ptr as some filesystems leave
* new_dentry->d_inode NULL and instantiate inode pointer later
*/
static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct dentry *new_dentry)
{
fsnotify_link_count(inode);
audit_inode_child(dir, new_dentry, AUDIT_TYPE_CHILD_CREATE);
fsnotify(dir, FS_CREATE, inode, FSNOTIFY_EVENT_INODE, new_dentry->d_name.name, 0);
}
/*
* fsnotify_mkdir - directory 'name' was created
*/
static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
{
audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
fsnotify_dirent(inode, dentry, FS_CREATE | FS_ISDIR);
}
/*
* fsnotify_access - file was read
*/
static inline void fsnotify_access(struct file *file)
{
const struct path *path = &file->f_path;
struct inode *inode = file_inode(file);
__u32 mask = FS_ACCESS;
if (S_ISDIR(inode->i_mode))
mask |= FS_ISDIR;
if (!(file->f_mode & FMODE_NONOTIFY))
fsnotify_path(inode, path, mask);
}
/*
* fsnotify_modify - file was modified
*/
static inline void fsnotify_modify(struct file *file)
{
const struct path *path = &file->f_path;
struct inode *inode = file_inode(file);
__u32 mask = FS_MODIFY;
if (S_ISDIR(inode->i_mode))
mask |= FS_ISDIR;
if (!(file->f_mode & FMODE_NONOTIFY))
fsnotify_path(inode, path, mask);
}
/*
* fsnotify_open - file was opened
*/
static inline void fsnotify_open(struct file *file)
{
const struct path *path = &file->f_path;
struct inode *inode = file_inode(file);
__u32 mask = FS_OPEN;
if (S_ISDIR(inode->i_mode))
mask |= FS_ISDIR;
if (file->f_flags & __FMODE_EXEC)
mask |= FS_OPEN_EXEC;
fsnotify_path(inode, path, mask);
}
/*
* fsnotify_close - file was closed
*/
static inline void fsnotify_close(struct file *file)
{
const struct path *path = &file->f_path;
struct inode *inode = file_inode(file);
fmode_t mode = file->f_mode;
__u32 mask = (mode & FMODE_WRITE) ? FS_CLOSE_WRITE : FS_CLOSE_NOWRITE;
if (S_ISDIR(inode->i_mode))
mask |= FS_ISDIR;
if (!(file->f_mode & FMODE_NONOTIFY))
fsnotify_path(inode, path, mask);
}
/*
* fsnotify_xattr - extended attributes were changed
*/
static inline void fsnotify_xattr(struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
__u32 mask = FS_ATTRIB;
if (S_ISDIR(inode->i_mode))
mask |= FS_ISDIR;
fsnotify_parent(NULL, dentry, mask);
fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
}
/*
* fsnotify_change - notify_change event. file was modified and/or metadata
* was changed.
*/
static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
{
struct inode *inode = dentry->d_inode;
__u32 mask = 0;
if (ia_valid & ATTR_UID)
mask |= FS_ATTRIB;
if (ia_valid & ATTR_GID)
mask |= FS_ATTRIB;
if (ia_valid & ATTR_SIZE)
mask |= FS_MODIFY;
/* both times implies a utime(s) call */
if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME))
mask |= FS_ATTRIB;
else if (ia_valid & ATTR_ATIME)
mask |= FS_ACCESS;
else if (ia_valid & ATTR_MTIME)
mask |= FS_MODIFY;
if (ia_valid & ATTR_MODE)
mask |= FS_ATTRIB;
if (mask) {
if (S_ISDIR(inode->i_mode))
mask |= FS_ISDIR;
fsnotify_parent(NULL, dentry, mask);
fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
}
}
#endif /* _LINUX_FS_NOTIFY_H */