Commit b9e4e3bd authored by Eric Paris's avatar Eric Paris
Browse files

fanotify: allow users to set an ignored_mask 



Change the sys_fanotify_mark() system call so users can set ignored_masks
on inodes.  Remember, if a user new sets a real mask, and only sets ignored
masks, the ignore will never be pinned in memory.  Thus ignored_masks can
be lost under memory pressure and the user may again get events they
previously thought were ignored.

Signed-off-by: default avatarEric Paris <eparis@redhat.com>
parent 32a4df13

fs/notify/fanotify/fanotify_user.c

+36 −18
Original line number Diff line number Diff line
@@ -296,13 +296,20 @@ out: 
	return ret;

}



static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark, __u32 mask)

static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,

					    __u32 mask,

					    unsigned int flags)

{

	__u32 oldmask;



	spin_lock(&fsn_mark->lock);

	if (!(flags & FAN_MARK_IGNORED_MASK)) {

		oldmask = fsn_mark->mask;

		fsnotify_set_mark_mask_locked(fsn_mark, (oldmask & ~mask));

	} else {

		oldmask = fsn_mark->ignored_mask;

		fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask & ~mask));

	}

	spin_unlock(&fsn_mark->lock);



	if (!(oldmask & ~mask))
@@ -312,7 +319,8 @@ static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark, __u3 
}



static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group,

					 struct vfsmount *mnt, __u32 mask)

					 struct vfsmount *mnt, __u32 mask,

					 unsigned int flags)

{

	struct fsnotify_mark *fsn_mark = NULL;

	__u32 removed;
@@ -321,7 +329,7 @@ static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group, 
	if (!fsn_mark)

		return -ENOENT;



	removed = fanotify_mark_remove_from_mask(fsn_mark, mask);

	removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags);

	fsnotify_put_mark(fsn_mark);

	if (removed & group->mask)

		fsnotify_recalc_group_mask(group);
@@ -332,7 +340,8 @@ static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group, 
}



static int fanotify_remove_inode_mark(struct fsnotify_group *group,

				      struct inode *inode, __u32 mask)

				      struct inode *inode, __u32 mask,

				      unsigned int flags)

{

	struct fsnotify_mark *fsn_mark = NULL;

	__u32 removed;
@@ -341,7 +350,7 @@ static int fanotify_remove_inode_mark(struct fsnotify_group *group, 
	if (!fsn_mark)

		return -ENOENT;



	removed = fanotify_mark_remove_from_mask(fsn_mark, mask);

	removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags);

	/* matches the fsnotify_find_inode_mark() */

	fsnotify_put_mark(fsn_mark);
@@ -353,20 +362,28 @@ static int fanotify_remove_inode_mark(struct fsnotify_group *group, 
	return 0;

}



static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark, __u32 mask)

static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,

				       __u32 mask,

				       unsigned int flags)

{

	__u32 oldmask;



	spin_lock(&fsn_mark->lock);

	if (!(flags & FAN_MARK_IGNORED_MASK)) {

		oldmask = fsn_mark->mask;

		fsnotify_set_mark_mask_locked(fsn_mark, (oldmask | mask));

	} else {

		oldmask = fsn_mark->ignored_mask;

		fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask | mask));

	}

	spin_unlock(&fsn_mark->lock);



	return mask & ~oldmask;

}



static int fanotify_add_vfsmount_mark(struct fsnotify_group *group,

				      struct vfsmount *mnt, __u32 mask)

				      struct vfsmount *mnt, __u32 mask,

				      unsigned int flags)

{

	struct fsnotify_mark *fsn_mark;

	__u32 added;
@@ -386,7 +403,7 @@ static int fanotify_add_vfsmount_mark(struct fsnotify_group *group, 
			return ret;

		}

	}

	added = fanotify_mark_add_to_mask(fsn_mark, mask);

	added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);

	fsnotify_put_mark(fsn_mark);

	if (added) {

		if (added & ~group->mask)
@@ -398,7 +415,8 @@ static int fanotify_add_vfsmount_mark(struct fsnotify_group *group, 
}



static int fanotify_add_inode_mark(struct fsnotify_group *group,

				   struct inode *inode, __u32 mask)

				   struct inode *inode, __u32 mask,

				   unsigned int flags)

{

	struct fsnotify_mark *fsn_mark;

	__u32 added;
@@ -420,7 +438,7 @@ static int fanotify_add_inode_mark(struct fsnotify_group *group, 
			return ret;

		}

	}

	added = fanotify_mark_add_to_mask(fsn_mark, mask);

	added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);

	fsnotify_put_mark(fsn_mark);

	if (added) {

		if (added & ~group->mask)
@@ -528,15 +546,15 @@ SYSCALL_DEFINE(fanotify_mark)(int fanotify_fd, unsigned int flags, 
	switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE)) {

	case FAN_MARK_ADD:

		if (flags & FAN_MARK_MOUNT)

			ret = fanotify_add_vfsmount_mark(group, mnt, mask);

			ret = fanotify_add_vfsmount_mark(group, mnt, mask, flags);

		else

			ret = fanotify_add_inode_mark(group, inode, mask);

			ret = fanotify_add_inode_mark(group, inode, mask, flags);

		break;

	case FAN_MARK_REMOVE:

		if (flags & FAN_MARK_MOUNT)

			ret = fanotify_remove_vfsmount_mark(group, mnt, mask);

			ret = fanotify_remove_vfsmount_mark(group, mnt, mask, flags);

		else

			ret = fanotify_remove_inode_mark(group, inode, mask);

			ret = fanotify_remove_inode_mark(group, inode, mask, flags);

		break;

	default:

		ret = -EINVAL;

include/linux/fanotify.h

+3 −1
Original line number Diff line number Diff line
@@ -30,12 +30,14 @@ 
#define FAN_MARK_DONT_FOLLOW	0x00000004

#define FAN_MARK_ONLYDIR	0x00000008

#define FAN_MARK_MOUNT		0x00000010

#define FAN_MARK_IGNORED_MASK	0x00000020



#define FAN_ALL_MARK_FLAGS	(FAN_MARK_ADD |\

				 FAN_MARK_REMOVE |\

				 FAN_MARK_DONT_FOLLOW |\

				 FAN_MARK_ONLYDIR |\

				 FAN_MARK_MOUNT)

				 FAN_MARK_MOUNT |\

				 FAN_MARK_IGNORED_MASK)



/*

 * All of the events - we build the list by hand so that we can add flags in

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