Commit dfc2d259 authored by Amir Goldstein's avatar Amir Goldstein Committed by Jan Kara
Browse files

fsnotify: replace inode pointer with an object id 

The event inode field is used only for comparison in queue merges and
cannot be dereferenced after handle_event(), because it does not hold a
refcount on the inode.

Replace it with an abstract id to do the same thing.

Link: https://lore.kernel.org/r/20200319151022.31456-8-amir73il@gmail.com


Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 017de65f

fs/notify/fanotify/fanotify.c

+2 −2
Original line number Diff line number Diff line
@@ -26,7 +26,7 @@ static bool should_merge(struct fsnotify_event *old_fsn, 
	old = FANOTIFY_E(old_fsn);

	new = FANOTIFY_E(new_fsn);



	if (old_fsn->inode != new_fsn->inode || old->pid != new->pid ||

	if (old_fsn->objectid != new_fsn->objectid || old->pid != new->pid ||

	    old->fh_type != new->fh_type || old->fh_len != new->fh_len)

		return false;
@@ -312,7 +312,7 @@ struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, 
	if (!event)

		goto out;

init: __maybe_unused

	fsnotify_init_event(&event->fse, inode);

	fsnotify_init_event(&event->fse, (unsigned long)inode);

	event->mask = mask;

	if (FAN_GROUP_FLAG(group, FAN_REPORT_TID))

		event->pid = get_pid(task_pid(current));

fs/notify/inotify/inotify_fsnotify.c

+2 −2
Original line number Diff line number Diff line
@@ -39,7 +39,7 @@ static bool event_compare(struct fsnotify_event *old_fsn, 
	if (old->mask & FS_IN_IGNORED)

		return false;

	if ((old->mask == new->mask) &&

	    (old_fsn->inode == new_fsn->inode) &&

	    (old_fsn->objectid == new_fsn->objectid) &&

	    (old->name_len == new->name_len) &&

	    (!old->name_len || !strcmp(old->name, new->name)))

		return true;
@@ -116,7 +116,7 @@ int inotify_handle_event(struct fsnotify_group *group, 
		mask &= ~IN_ISDIR;



	fsn_event = &event->fse;

	fsnotify_init_event(fsn_event, inode);

	fsnotify_init_event(fsn_event, (unsigned long)inode);

	event->mask = mask;

	event->wd = i_mark->wd;

	event->sync_cookie = cookie;

fs/notify/inotify/inotify_user.c

+1 −1
Original line number Diff line number Diff line
@@ -635,7 +635,7 @@ static struct fsnotify_group *inotify_new_group(unsigned int max_events) 
		return ERR_PTR(-ENOMEM);

	}

	group->overflow_event = &oevent->fse;

	fsnotify_init_event(group->overflow_event, NULL);

	fsnotify_init_event(group->overflow_event, 0);

	oevent->mask = FS_Q_OVERFLOW;

	oevent->wd = -1;

	oevent->sync_cookie = 0;

include/linux/fsnotify_backend.h

+3 −4
Original line number Diff line number Diff line
@@ -132,8 +132,7 @@ struct fsnotify_ops { 
 */

struct fsnotify_event {

	struct list_head list;

	/* inode may ONLY be dereferenced during handle_event(). */

	struct inode *inode;	/* either the inode the event happened to or its parent */

	unsigned long objectid;	/* identifier for queue merges */

};



/*
@@ -526,10 +525,10 @@ extern void fsnotify_finish_user_wait(struct fsnotify_iter_info *iter_info); 
extern bool fsnotify_prepare_user_wait(struct fsnotify_iter_info *iter_info);



static inline void fsnotify_init_event(struct fsnotify_event *event,

				       struct inode *inode)

				       unsigned long objectid)

{

	INIT_LIST_HEAD(&event->list);

	event->inode = inode;

	event->objectid = objectid;

}



#else