Commit c9d4603b authored by Amir Goldstein's avatar Amir Goldstein Committed by Jan Kara
Browse files

fsnotify: create helper fsnotify_update_sb_watchers() 



We would like to count watched objects by priority group, so we will need
to update the watched object counter after adding/removing marks.

Create a helper fsnotify_update_sb_watchers() and call it after
attaching/detaching a mark, instead of fsnotify_{get,put}_sb_watchers()
only after attaching/detaching a connector.

Soon, we will use this helper to count watched objects by the highest
watching priority group.

Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Message-Id: <20240317184154.1200192-7-amir73il@gmail.com>
parent 687c217c

fs/notify/mark.c

+22 −14
Original line number Diff line number Diff line
@@ -154,21 +154,24 @@ static void fsnotify_put_inode_ref(struct inode *inode) 
	iput(inode);

}



static void fsnotify_get_sb_watchers(struct fsnotify_mark_connector *conn)

/*

 * Grab or drop watched objects reference depending on whether the connector

 * is attached and has any marks attached.

 */

static void fsnotify_update_sb_watchers(struct super_block *sb,

					struct fsnotify_mark_connector *conn)

{

	struct super_block *sb = fsnotify_connector_sb(conn);

	bool is_watched = conn->flags & FSNOTIFY_CONN_FLAG_IS_WATCHED;

	bool has_marks = conn->obj && !hlist_empty(&conn->list);



	if (sb)

	if (has_marks && !is_watched) {

		conn->flags |= FSNOTIFY_CONN_FLAG_IS_WATCHED;

		fsnotify_get_sb_watched_objects(sb);

}



static void fsnotify_put_sb_watchers(struct fsnotify_mark_connector *conn)

{

	struct super_block *sb = fsnotify_connector_sb(conn);



	if (sb)

	} else if (!has_marks && is_watched) {

		conn->flags &= ~FSNOTIFY_CONN_FLAG_IS_WATCHED;

		fsnotify_put_sb_watched_objects(sb);

	}

}



/*

 * Grab or drop inode reference for the connector if needed.
@@ -266,6 +269,7 @@ static void *fsnotify_detach_connector_from_object( 
					unsigned int *type)

{

	fsnotify_connp_t *connp = fsnotify_object_connp(conn->obj, conn->type);

	struct super_block *sb = fsnotify_connector_sb(conn);

	struct inode *inode = NULL;



	*type = conn->type;
@@ -285,10 +289,10 @@ static void *fsnotify_detach_connector_from_object( 
		fsnotify_conn_sb(conn)->s_fsnotify_mask = 0;

	}



	fsnotify_put_sb_watchers(conn);

	rcu_assign_pointer(*connp, NULL);

	conn->obj = NULL;

	conn->type = FSNOTIFY_OBJ_TYPE_DETACHED;

	fsnotify_update_sb_watchers(sb, conn);



	return inode;

}
@@ -340,6 +344,11 @@ void fsnotify_put_mark(struct fsnotify_mark *mark) 
		objp = fsnotify_detach_connector_from_object(conn, &type);

		free_conn = true;

	} else {

		struct super_block *sb = fsnotify_connector_sb(conn);



		/* Update watched objects after detaching mark */

		if (sb)

			fsnotify_update_sb_watchers(sb, conn);

		objp = __fsnotify_recalc_mask(conn);

		type = conn->type;

	}
@@ -581,10 +590,7 @@ static int fsnotify_attach_connector_to_object(fsnotify_connp_t *connp, 
	if (cmpxchg(connp, NULL, conn)) {

		/* Someone else created list structure for us */

		kmem_cache_free(fsnotify_mark_connector_cachep, conn);

		return 0;

	}



	fsnotify_get_sb_watchers(conn);

	return 0;

}
@@ -624,6 +630,7 @@ static struct fsnotify_mark_connector *fsnotify_grab_connector( 
static int fsnotify_add_mark_list(struct fsnotify_mark *mark, void *obj,

				  unsigned int obj_type, int add_flags)

{

	struct super_block *sb = fsnotify_object_sb(obj, obj_type);

	struct fsnotify_mark *lmark, *last = NULL;

	struct fsnotify_mark_connector *conn;

	fsnotify_connp_t *connp;
@@ -673,6 +680,7 @@ static int fsnotify_add_mark_list(struct fsnotify_mark *mark, void *obj, 
	/* mark should be the last entry.  last is the current last entry */

	hlist_add_behind_rcu(&mark->obj_list, &last->obj_list);

added:

	fsnotify_update_sb_watchers(sb, conn);

	/*

	 * Since connector is attached to object using cmpxchg() we are

	 * guaranteed that connector initialization is fully visible by anyone

include/linux/fsnotify_backend.h

+1 −0
Original line number Diff line number Diff line
@@ -465,6 +465,7 @@ FSNOTIFY_ITER_FUNCS(sb, SB) 
struct fsnotify_mark_connector {

	spinlock_t lock;

	unsigned short type;	/* Type of object [lock] */

#define FSNOTIFY_CONN_FLAG_IS_WATCHED	0x01

#define FSNOTIFY_CONN_FLAG_HAS_IREF	0x02

	unsigned short flags;	/* flags [lock] */

	union {