Commit e54183fa authored by Amir Goldstein's avatar Amir Goldstein Committed by Jan Kara
Browse files

fsnotify: generate FS_RENAME event with rich information 

The dnotify FS_DN_RENAME event is used to request notification about
a move within the same parent directory and was always coupled with
the FS_MOVED_FROM event.

Rename the FS_DN_RENAME event flag to FS_RENAME, decouple it from
FS_MOVED_FROM and report it with the moved dentry instead of the moved
inode, so it has the information about both old and new parent and name.

Generate the FS_RENAME event regardless of same parent dir and apply
the "same parent" rule in the generic fsnotify_handle_event() helper
that is used to call backends with ->handle_inode_event() method
(i.e. dnotify).  The ->handle_inode_event() method is not rich enough to
report both old and new parent and name anyway.

The enriched event is reported to fanotify over the ->handle_event()
method with the old and new dir inode marks in marks array slots for
ITER_TYPE_INODE and a new iter type slot ITER_TYPE_INODE2.

The enriched event will be used for reporting old and new parent+name to
fanotify groups with FAN_RENAME events.

Link: https://lore.kernel.org/r/20211129201537.1932819-5-amir73il@gmail.com


Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent d61fd650

fs/notify/dnotify/dnotify.c

+1 −1
Original line number Diff line number Diff line
@@ -196,7 +196,7 @@ static __u32 convert_arg(unsigned long arg) 
	if (arg & DN_ATTRIB)

		new_mask |= FS_ATTRIB;

	if (arg & DN_RENAME)

		new_mask |= FS_DN_RENAME;

		new_mask |= FS_RENAME;

	if (arg & DN_CREATE)

		new_mask |= (FS_CREATE | FS_MOVED_TO);

fs/notify/fsnotify.c

+29 −8
Original line number Diff line number Diff line
@@ -279,6 +279,18 @@ static int fsnotify_handle_event(struct fsnotify_group *group, __u32 mask, 
	    WARN_ON_ONCE(fsnotify_iter_vfsmount_mark(iter_info)))

		return 0;



	/*

	 * For FS_RENAME, 'dir' is old dir and 'data' is new dentry.

	 * The only ->handle_inode_event() backend that supports FS_RENAME is

	 * dnotify, where it means file was renamed within same parent.

	 */

	if (mask & FS_RENAME) {

		struct dentry *moved = fsnotify_data_dentry(data, data_type);



		if (dir != moved->d_parent->d_inode)

			return 0;

	}



	if (parent_mark) {

		/*

		 * parent_mark indicates that the parent inode is watching
@@ -469,7 +481,9 @@ int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir, 
	struct super_block *sb = fsnotify_data_sb(data, data_type);

	struct fsnotify_iter_info iter_info = {};

	struct mount *mnt = NULL;

	struct inode *parent = NULL;

	struct inode *inode2 = NULL;

	struct dentry *moved;

	int inode2_type;

	int ret = 0;

	__u32 test_mask, marks_mask;
@@ -479,12 +493,19 @@ int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir, 
	if (!inode) {

		/* Dirent event - report on TYPE_INODE to dir */

		inode = dir;

		/* For FS_RENAME, inode is old_dir and inode2 is new_dir */

		if (mask & FS_RENAME) {

			moved = fsnotify_data_dentry(data, data_type);

			inode2 = moved->d_parent->d_inode;

			inode2_type = FSNOTIFY_ITER_TYPE_INODE2;

		}

	} else if (mask & FS_EVENT_ON_CHILD) {

		/*

		 * Event on child - report on TYPE_PARENT to dir if it is

		 * watching children and on TYPE_INODE to child.

		 */

		parent = dir;

		inode2 = dir;

		inode2_type = FSNOTIFY_ITER_TYPE_PARENT;

	}



	/*
@@ -497,7 +518,7 @@ int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir, 
	if (!sb->s_fsnotify_marks &&

	    (!mnt || !mnt->mnt_fsnotify_marks) &&

	    (!inode || !inode->i_fsnotify_marks) &&

	    (!parent || !parent->i_fsnotify_marks))

	    (!inode2 || !inode2->i_fsnotify_marks))

		return 0;



	marks_mask = sb->s_fsnotify_mask;
@@ -505,8 +526,8 @@ int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir, 
		marks_mask |= mnt->mnt_fsnotify_mask;

	if (inode)

		marks_mask |= inode->i_fsnotify_mask;

	if (parent)

		marks_mask |= parent->i_fsnotify_mask;

	if (inode2)

		marks_mask |= inode2->i_fsnotify_mask;





	/*
@@ -529,9 +550,9 @@ int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir, 
		iter_info.marks[FSNOTIFY_ITER_TYPE_INODE] =

			fsnotify_first_mark(&inode->i_fsnotify_marks);

	}

	if (parent) {

		iter_info.marks[FSNOTIFY_ITER_TYPE_PARENT] =

			fsnotify_first_mark(&parent->i_fsnotify_marks);

	if (inode2) {

		iter_info.marks[inode2_type] =

			fsnotify_first_mark(&inode2->i_fsnotify_marks);

	}



	/*

include/linux/dnotify.h

+1 −1
Original line number Diff line number Diff line
@@ -26,7 +26,7 @@ struct dnotify_struct { 
			    FS_MODIFY | FS_MODIFY_CHILD |\

			    FS_ACCESS | FS_ACCESS_CHILD |\

			    FS_ATTRIB | FS_ATTRIB_CHILD |\

			    FS_CREATE | FS_DN_RENAME |\

			    FS_CREATE | FS_RENAME |\

			    FS_MOVED_FROM | FS_MOVED_TO)



extern int dir_notify_enable;

include/linux/fsnotify.h

+6 −3
Original line number Diff line number Diff line
@@ -144,16 +144,19 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir, 
	u32 fs_cookie = fsnotify_get_cookie();

	__u32 old_dir_mask = FS_MOVED_FROM;

	__u32 new_dir_mask = FS_MOVED_TO;

	__u32 rename_mask = FS_RENAME;

	const struct qstr *new_name = &moved->d_name;



	if (old_dir == new_dir)

		old_dir_mask |= FS_DN_RENAME;



	if (isdir) {

		old_dir_mask |= FS_ISDIR;

		new_dir_mask |= FS_ISDIR;

		rename_mask |= FS_ISDIR;

	}



	/* Event with information about both old and new parent+name */

	fsnotify_name(rename_mask, moved, FSNOTIFY_EVENT_DENTRY,

		      old_dir, old_name, 0);



	fsnotify_name(old_dir_mask, source, FSNOTIFY_EVENT_INODE,

		      old_dir, old_name, fs_cookie);

	fsnotify_name(new_dir_mask, source, FSNOTIFY_EVENT_INODE,

include/linux/fsnotify_backend.h

+4 −3
Original line number Diff line number Diff line
@@ -63,7 +63,7 @@ 
 */

#define FS_EVENT_ON_CHILD	0x08000000



#define FS_DN_RENAME		0x10000000	/* file renamed */

#define FS_RENAME		0x10000000	/* File was renamed */

#define FS_DN_MULTISHOT		0x20000000	/* dnotify multishot */

#define FS_ISDIR		0x40000000	/* event occurred against dir */

#define FS_IN_ONESHOT		0x80000000	/* only send event once */
@@ -76,7 +76,7 @@ 
 * The watching parent may get an FS_ATTRIB|FS_EVENT_ON_CHILD event

 * when a directory entry inside a child subdir changes.

 */

#define ALL_FSNOTIFY_DIRENT_EVENTS	(FS_CREATE | FS_DELETE | FS_MOVE)

#define ALL_FSNOTIFY_DIRENT_EVENTS (FS_CREATE | FS_DELETE | FS_MOVE | FS_RENAME)



#define ALL_FSNOTIFY_PERM_EVENTS (FS_OPEN_PERM | FS_ACCESS_PERM | \

				  FS_OPEN_EXEC_PERM)
@@ -101,7 +101,7 @@ 
/* Events that can be reported to backends */

#define ALL_FSNOTIFY_EVENTS (ALL_FSNOTIFY_DIRENT_EVENTS | \

			     FS_EVENTS_POSS_ON_CHILD | \

			     FS_DELETE_SELF | FS_MOVE_SELF | FS_DN_RENAME | \

			     FS_DELETE_SELF | FS_MOVE_SELF | \

			     FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED | \

			     FS_ERROR)
@@ -349,6 +349,7 @@ enum fsnotify_iter_type { 
	FSNOTIFY_ITER_TYPE_VFSMOUNT,

	FSNOTIFY_ITER_TYPE_SB,

	FSNOTIFY_ITER_TYPE_PARENT,

	FSNOTIFY_ITER_TYPE_INODE2,

	FSNOTIFY_ITER_TYPE_COUNT

};