fanotify: generalize test for FAN_REPORT_FID

As preparation for new flags that report fids, define a bit set
of flags for a group reporting fids, currently containing the
only bit FAN_REPORT_FID.

Link: https://lore.kernel.org/r/20200716084230.30611-5-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/notify/fanotify/fanotify.c

@@ -207,13 +207,14 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group,
 	__u32 test_mask, user_mask = FANOTIFY_OUTGOING_EVENTS |
 				     FANOTIFY_EVENT_FLAGS;
 	const struct path *path = fsnotify_data_path(data, data_type);
+	unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
 	struct fsnotify_mark *mark;
 	int type;
 
 	pr_debug("%s: report_mask=%x mask=%x data=%p data_type=%d\n",
 		 __func__, iter_info->report_mask, event_mask, data, data_type);
 
-	if (!FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
+	if (!fid_mode) {
 		/* Do we have path to open a file descriptor? */
 		if (!path)
 			return 0;
@@ -264,7 +265,7 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group,
 	 * fanotify_alloc_event() when group is reporting fid as indication
 	 * that event happened on child.
 	 */
-	if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
+	if (fid_mode) {
 		/* Do not report event flags without any event */
 		if (!(test_mask & ~FANOTIFY_EVENT_FLAGS))
 			return 0;
@@ -424,6 +425,7 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
 	gfp_t gfp = GFP_KERNEL_ACCOUNT;
 	struct inode *id = fanotify_fid_inode(mask, data, data_type, dir);
 	const struct path *path = fsnotify_data_path(data, data_type);
+	unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
 	bool name_event = false;
 
 	/*
@@ -444,7 +446,7 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
 		event = fanotify_alloc_perm_event(path, gfp);
 	} else if (name_event && file_name) {
 		event = fanotify_alloc_name_event(id, fsid, file_name, gfp);
-	} else if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
+	} else if (fid_mode) {
 		event = fanotify_alloc_fid_event(id, fsid, gfp);
 	} else {
 		event = fanotify_alloc_path_event(path, gfp);
@@ -551,7 +553,7 @@ static int fanotify_handle_event(struct fsnotify_group *group, u32 mask,
 			return 0;
 	}
 
-	if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
+	if (FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS)) {
 		fsid = fanotify_get_fsid(iter_info);
 		/* Racing with mark destruction or creation? */
 		if (!fsid.val[0] && !fsid.val[1])

fs/notify/fanotify/fanotify_user.c

@@ -100,7 +100,7 @@ static struct fanotify_event *get_one_event(struct fsnotify_group *group,
 	if (fsnotify_notify_queue_is_empty(group))
 		goto out;
 
-	if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
+	if (FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS)) {
 		event_size += fanotify_event_info_len(
 			FANOTIFY_E(fsnotify_peek_first_event(group)));
 	}
@@ -882,7 +882,7 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
 		return -EINVAL;
 	}
 
-	if ((flags & FAN_REPORT_FID) &&
+	if ((flags & FANOTIFY_FID_BITS) &&
 	    (flags & FANOTIFY_CLASS_BITS) != FAN_CLASS_NOTIF)
 		return -EINVAL;
 
@@ -1040,7 +1040,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	__kernel_fsid_t __fsid, *fsid = NULL;
 	u32 valid_mask = FANOTIFY_EVENTS | FANOTIFY_EVENT_FLAGS;
 	unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
-	unsigned int obj_type;
+	unsigned int obj_type, fid_mode;
 	int ret;
 
 	pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n",
@@ -1113,9 +1113,9 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	 * inode events are not supported on a mount mark, because they do not
 	 * carry enough information (i.e. path) to be filtered by mount point.
 	 */
+	fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
 	if (mask & FANOTIFY_INODE_EVENTS &&
-	    (!FAN_GROUP_FLAG(group, FAN_REPORT_FID) ||
+	    (!fid_mode || mark_type == FAN_MARK_MOUNT))
-	     mark_type == FAN_MARK_MOUNT))
 		goto fput_and_out;
 
 	if (flags & FAN_MARK_FLUSH) {
@@ -1140,7 +1140,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 			goto path_put_and_out;
 	}
 
-	if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
+	if (fid_mode) {
 		ret = fanotify_test_fid(&path, &__fsid);
 		if (ret)
 			goto path_put_and_out;

include/linux/fanotify.h

@@ -18,8 +18,10 @@
 #define FANOTIFY_CLASS_BITS	(FAN_CLASS_NOTIF | FAN_CLASS_CONTENT | \
 				 FAN_CLASS_PRE_CONTENT)
 
-#define FANOTIFY_INIT_FLAGS	(FANOTIFY_CLASS_BITS | \
+#define FANOTIFY_FID_BITS	(FAN_REPORT_FID)
-				 FAN_REPORT_TID | FAN_REPORT_FID | \
+
+#define FANOTIFY_INIT_FLAGS	(FANOTIFY_CLASS_BITS | FANOTIFY_FID_BITS | \
+				 FAN_REPORT_TID | \
 				 FAN_CLOEXEC | FAN_NONBLOCK | \
 				 FAN_UNLIMITED_QUEUE | FAN_UNLIMITED_MARKS)