rbd: refactor rbd_wait_state_locked()

In preparation for lock_timeout option, make rbd_wait_state_locked()
return error codes.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 07dc5419bd63bec43af2de5da0a485ec99bab7cd..f4b1b91e6d4dee0fc07d996557328c78a49c23f5 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -3533,9 +3533,21 @@ static int rbd_obj_method_sync(struct rbd_device *rbd_dev,
 /*
  * lock_rwsem must be held for read
  */
-static void rbd_wait_state_locked(struct rbd_device *rbd_dev)
+static int rbd_wait_state_locked(struct rbd_device *rbd_dev, bool may_acquire)
 {
        DEFINE_WAIT(wait);
+       int ret = 0;
+
+       if (test_bit(RBD_DEV_FLAG_BLACKLISTED, &rbd_dev->flags))
+               return -EBLACKLISTED;
+
+       if (rbd_dev->lock_state == RBD_LOCK_STATE_LOCKED)
+               return 0;
+
+       if (!may_acquire) {
+               rbd_warn(rbd_dev, "exclusive lock required");
+               return -EROFS;
+       }
 
        do {
                /*
@@ -3549,10 +3561,14 @@ static void rbd_wait_state_locked(struct rbd_device *rbd_dev)
                up_read(&rbd_dev->lock_rwsem);
                schedule();
                down_read(&rbd_dev->lock_rwsem);
-       } while (rbd_dev->lock_state != RBD_LOCK_STATE_LOCKED &&
-                !test_bit(RBD_DEV_FLAG_BLACKLISTED, &rbd_dev->flags));
+               if (test_bit(RBD_DEV_FLAG_BLACKLISTED, &rbd_dev->flags)) {
+                       ret = -EBLACKLISTED;
+                       break;
+               }
+       } while (rbd_dev->lock_state != RBD_LOCK_STATE_LOCKED);
 
        finish_wait(&rbd_dev->lock_waitq, &wait);
+       return ret;
 }
 
 static void rbd_queue_workfn(struct work_struct *work)
@@ -3638,19 +3654,10 @@ static void rbd_queue_workfn(struct work_struct *work)
            (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 &&
-                   !test_bit(RBD_DEV_FLAG_BLACKLISTED, &rbd_dev->flags)) {
-                       if (rbd_dev->opts->exclusive) {
-                               rbd_warn(rbd_dev, "exclusive lock required");
-                               result = -EROFS;
-                               goto err_unlock;
-                       }
-                       rbd_wait_state_locked(rbd_dev);
-               }
-               if (test_bit(RBD_DEV_FLAG_BLACKLISTED, &rbd_dev->flags)) {
-                       result = -EBLACKLISTED;
+               result = rbd_wait_state_locked(rbd_dev,
+                                              !rbd_dev->opts->exclusive);
+               if (result)
                        goto err_unlock;
-               }
        }
 
        img_request = rbd_img_request_create(rbd_dev, op_type, snapc);
@@ -5216,6 +5223,8 @@ static void rbd_dev_image_unlock(struct rbd_device *rbd_dev)
 
 static int rbd_add_acquire_lock(struct rbd_device *rbd_dev)
 {
+       int ret;
+
        if (!(rbd_dev->header.features & RBD_FEATURE_EXCLUSIVE_LOCK)) {
                rbd_warn(rbd_dev, "exclusive-lock feature is not enabled");
                return -EINVAL;
@@ -5223,9 +5232,9 @@ static int rbd_add_acquire_lock(struct rbd_device *rbd_dev)
 
        /* FIXME: "rbd map --exclusive" should be in interruptible */
        down_read(&rbd_dev->lock_rwsem);
-       rbd_wait_state_locked(rbd_dev);
+       ret = rbd_wait_state_locked(rbd_dev, true);
        up_read(&rbd_dev->lock_rwsem);
-       if (test_bit(RBD_DEV_FLAG_BLACKLISTED, &rbd_dev->flags)) {
+       if (ret) {
                rbd_warn(rbd_dev, "failed to acquire exclusive lock");
                return -EROFS;
        }