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Commit f9bebd58 authored by Ilya Dryomov's avatar Ilya Dryomov
Browse files

rbd: kill rbd_is_lock_supported() 



Currently the exclusive lock is acquired only if the mapping is
writable, i.e. an image HEAD mapped in rw mode.  This means that we
don't acquire the lock for executing a read from a snapshot or an image
HEAD mapped in ro mode, even if lock_on_read is set.  This is somewhat
weird and inconsistent with "no automatic exclusive lock transfers"
mode, where the lock is acquired unconditionally.

Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
Reviewed-by: default avatarJason Dillaman <dillaman@redhat.com>
parent 14bb211d

drivers/block/rbd.c

+3 −11
Original line number Diff line number Diff line
@@ -478,13 +478,6 @@ static int minor_to_rbd_dev_id(int minor) 
	return minor >> RBD_SINGLE_MAJOR_PART_SHIFT;

}



static bool rbd_is_lock_supported(struct rbd_device *rbd_dev)

{

	return (rbd_dev->header.features & RBD_FEATURE_EXCLUSIVE_LOCK) &&

	       rbd_dev->spec->snap_id == CEPH_NOSNAP &&

	       !rbd_dev->mapping.read_only;

}



static bool __rbd_is_lock_owner(struct rbd_device *rbd_dev)

{

	return rbd_dev->lock_state == RBD_LOCK_STATE_LOCKED ||
@@ -4052,10 +4045,6 @@ static void rbd_queue_workfn(struct work_struct *work) 
	if (op_type != OBJ_OP_READ) {

		snapc = rbd_dev->header.snapc;

		ceph_get_snap_context(snapc);

		must_be_locked = rbd_is_lock_supported(rbd_dev);

	} else {

		must_be_locked = rbd_dev->opts->lock_on_read &&

					rbd_is_lock_supported(rbd_dev);

	}

	up_read(&rbd_dev->header_rwsem);
@@ -4066,6 +4055,9 @@ static void rbd_queue_workfn(struct work_struct *work) 
		goto err_rq;

	}



	must_be_locked =

	    (rbd_dev->header.features & RBD_FEATURE_EXCLUSIVE_LOCK) &&

	    (op_type != OBJ_OP_READ || rbd_dev->opts->lock_on_read);

	if (must_be_locked) {

		down_read(&rbd_dev->lock_rwsem);

		if (rbd_dev->lock_state != RBD_LOCK_STATE_LOCKED &&