Commit 2d143955 authored by Andreas Gruenbacher's avatar Andreas Gruenbacher
Browse files

gfs2: Improve gfs2_upgrade_iopen_glock comment 



Improve the comment describing the inode and iopen glock interactions
and the glock poking related to inode evict.

Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
parent 9ffa1888

fs/gfs2/super.c

+16 −8
Original line number Diff line number Diff line
@@ -1175,15 +1175,23 @@ static bool gfs2_upgrade_iopen_glock(struct inode *inode) 
	gfs2_glock_dq_wait(gh);



	/*

	 * If there are no other lock holders, we'll get the lock immediately.

	 * If there are no other lock holders, we will immediately get

	 * exclusive access to the iopen glock here.

	 *

	 * Otherwise, the other nodes holding the lock will be notified about

	 * our locking request.  If they don't have the inode open, they'll

	 * evict the cached inode and release the lock.  Otherwise, if they

	 * poke the inode glock, we'll take this as an indication that they

	 * still need the iopen glock and that they'll take care of deleting

	 * the inode when they're done.  As a last resort, if another node

	 * keeps holding the iopen glock without showing any activity on the

	 * inode glock, we'll eventually time out.

	 * our locking request.  If they do not have the inode open, they are

	 * expected to evict the cached inode and release the lock, allowing us

	 * to proceed.

	 *

	 * Otherwise, if they cannot evict the inode, they are expected to poke

	 * the inode glock (note: not the iopen glock).  We will notice that

	 * and stop waiting for the iopen glock immediately.  The other node(s)

	 * are then expected to take care of deleting the inode when they no

	 * longer use it.

	 *

	 * As a last resort, if another node keeps holding the iopen glock

	 * without showing any activity on the inode glock, we will eventually

	 * time out and fail the iopen glock upgrade.

	 *

	 * Note that we're passing the LM_FLAG_TRY_1CB flag to the first

	 * locking request as an optimization to notify lock holders as soon as