Commit ec44610f authored by Amir Goldstein's avatar Amir Goldstein Committed by Jan Kara
Browse files

fsnotify: count all objects with attached connectors 

Rename s_fsnotify_inode_refs to s_fsnotify_connectors and count all
objects with attached connectors, not only inodes with attached
connectors.

This will be used to optimize fsnotify() calls on sb without any
type of marks.

Link: https://lore.kernel.org/r/20210810151220.285179-4-amir73il@gmail.com


Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Reviewed-by: default avatarMatthew Bobrowski <repnop@google.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 11fa333b

fs/notify/fsnotify.c

+3 −3
Original line number Diff line number Diff line
@@ -87,15 +87,15 @@ static void fsnotify_unmount_inodes(struct super_block *sb) 


	if (iput_inode)

		iput(iput_inode);

	/* Wait for outstanding inode references from connectors */

	wait_var_event(&sb->s_fsnotify_inode_refs,

		       !atomic_long_read(&sb->s_fsnotify_inode_refs));

}



void fsnotify_sb_delete(struct super_block *sb)

{

	fsnotify_unmount_inodes(sb);

	fsnotify_clear_marks_by_sb(sb);

	/* Wait for outstanding object references from connectors */

	wait_var_event(&sb->s_fsnotify_connectors,

		       !atomic_long_read(&sb->s_fsnotify_connectors));

}



/*

fs/notify/fsnotify.h

+15 −0
Original line number Diff line number Diff line
@@ -27,6 +27,21 @@ static inline struct super_block *fsnotify_conn_sb( 
	return container_of(conn->obj, struct super_block, s_fsnotify_marks);

}



static inline struct super_block *fsnotify_connector_sb(

				struct fsnotify_mark_connector *conn)

{

	switch (conn->type) {

	case FSNOTIFY_OBJ_TYPE_INODE:

		return fsnotify_conn_inode(conn)->i_sb;

	case FSNOTIFY_OBJ_TYPE_VFSMOUNT:

		return fsnotify_conn_mount(conn)->mnt.mnt_sb;

	case FSNOTIFY_OBJ_TYPE_SB:

		return fsnotify_conn_sb(conn);

	default:

		return NULL;

	}

}



/* destroy all events sitting in this groups notification queue */

extern void fsnotify_flush_notify(struct fsnotify_group *group);

fs/notify/mark.c

+21 −3
Original line number Diff line number Diff line
@@ -172,7 +172,7 @@ static void fsnotify_connector_destroy_workfn(struct work_struct *work) 
static void fsnotify_get_inode_ref(struct inode *inode)

{

	ihold(inode);

	atomic_long_inc(&inode->i_sb->s_fsnotify_inode_refs);

	atomic_long_inc(&inode->i_sb->s_fsnotify_connectors);

}



static void fsnotify_put_inode_ref(struct inode *inode)
@@ -180,8 +180,24 @@ static void fsnotify_put_inode_ref(struct inode *inode) 
	struct super_block *sb = inode->i_sb;



	iput(inode);

	if (atomic_long_dec_and_test(&sb->s_fsnotify_inode_refs))

		wake_up_var(&sb->s_fsnotify_inode_refs);

	if (atomic_long_dec_and_test(&sb->s_fsnotify_connectors))

		wake_up_var(&sb->s_fsnotify_connectors);

}



static void fsnotify_get_sb_connectors(struct fsnotify_mark_connector *conn)

{

	struct super_block *sb = fsnotify_connector_sb(conn);



	if (sb)

		atomic_long_inc(&sb->s_fsnotify_connectors);

}



static void fsnotify_put_sb_connectors(struct fsnotify_mark_connector *conn)

{

	struct super_block *sb = fsnotify_connector_sb(conn);



	if (sb && atomic_long_dec_and_test(&sb->s_fsnotify_connectors))

		wake_up_var(&sb->s_fsnotify_connectors);

}



static void *fsnotify_detach_connector_from_object(
@@ -203,6 +219,7 @@ static void *fsnotify_detach_connector_from_object( 
		fsnotify_conn_sb(conn)->s_fsnotify_mask = 0;

	}



	fsnotify_put_sb_connectors(conn);

	rcu_assign_pointer(*(conn->obj), NULL);

	conn->obj = NULL;

	conn->type = FSNOTIFY_OBJ_TYPE_DETACHED;
@@ -504,6 +521,7 @@ static int fsnotify_attach_connector_to_object(fsnotify_connp_t *connp, 
		inode = fsnotify_conn_inode(conn);

		fsnotify_get_inode_ref(inode);

	}

	fsnotify_get_sb_connectors(conn);



	/*

	 * cmpxchg() provides the barrier so that readers of *connp can see

include/linux/fs.h

+5 −2
Original line number Diff line number Diff line
@@ -1507,8 +1507,11 @@ struct super_block { 
	/* Number of inodes with nlink == 0 but still referenced */

	atomic_long_t s_remove_count;



	/* Pending fsnotify inode refs */

	atomic_long_t s_fsnotify_inode_refs;

	/*

	 * Number of inode/mount/sb objects that are being watched, note that

	 * inodes objects are currently double-accounted.

	 */

	atomic_long_t s_fsnotify_connectors;



	/* Being remounted read-only */

	int s_readonly_remount;