[Cluster-devel] [PATCH dlm/next] fs: dlm: handle -EBUSY as first for unlock

[Alexander Aring <aahringo@redhat.com>]

This patch checks on -EBUSY for dlm_unlock() for non CANCEL or
FORCEUNLOCK case validation at first. Similar like it's done for
dlm_lock(). Although the current way looks okay we should anyway
moving the -EBUSY check at first after doing a check on -EINVAL
regarding to the lkb state. If new -EINVAL checks are added it
should be considered that some lkb fields are in a stable state
only when the lkb is in a non -EBUSY state. This patch is trying to
avoid such future mistake.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
 fs/dlm/lock.c | 44 ++++++++++++++++++++++----------------------
 1 file changed, 22 insertions(+), 22 deletions(-)

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 7d5f94867e45..75313435b39d 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -2928,23 +2928,12 @@ static int validate_lock_args(struct dlm_ls *ls, struct dlm_lkb *lkb,
 static int validate_unlock_args(struct dlm_lkb *lkb, struct dlm_args *args)
 {
 	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
-	int rv = -EINVAL;
-
-	if (lkb->lkb_flags & DLM_IFL_MSTCPY) {
-		log_error(ls, "unlock on MSTCPY %x", lkb->lkb_id);
-		dlm_print_lkb(lkb);
-		goto out;
-	}
-
-	/* an lkb may still exist even though the lock is EOL'ed due to a
-	   cancel, unlock or failed noqueue request; an app can't use these
-	   locks; return same error as if the lkid had not been found at all */
+	int rv = -EBUSY;
 
-	if (lkb->lkb_flags & DLM_IFL_ENDOFLIFE) {
-		log_debug(ls, "unlock on ENDOFLIFE %x", lkb->lkb_id);
-		rv = -ENOENT;
+	/* normal unlock not allowed if there's any op in progress */
+	if (!(args->flags & (DLM_LKF_CANCEL | DLM_LKF_FORCEUNLOCK)) &&
+	    (lkb->lkb_wait_type || lkb->lkb_wait_count))
 		goto out;
-	}
 
 	/* an lkb may be waiting for an rsb lookup to complete where the
 	   lookup was initiated by another lock */
@@ -2959,7 +2948,24 @@ static int validate_unlock_args(struct dlm_lkb *lkb, struct dlm_args *args)
 			unhold_lkb(lkb); /* undoes create_lkb() */
 		}
 		/* caller changes -EBUSY to 0 for CANCEL and FORCEUNLOCK */
-		rv = -EBUSY;
+		goto out;
+	}
+
+	rv = -EINVAL;
+	if (lkb->lkb_flags & DLM_IFL_MSTCPY) {
+		log_error(ls, "unlock on MSTCPY %x", lkb->lkb_id);
+		dlm_print_lkb(lkb);
+		goto out;
+	}
+
+	/* an lkb may still exist even though the lock is EOL'ed due to a
+	 * cancel, unlock or failed noqueue request; an app can't use these
+	 * locks; return same error as if the lkid had not been found at all
+	 */
+
+	if (lkb->lkb_flags & DLM_IFL_ENDOFLIFE) {
+		log_debug(ls, "unlock on ENDOFLIFE %x", lkb->lkb_id);
+		rv = -ENOENT;
 		goto out;
 	}
 
@@ -3032,14 +3038,8 @@ static int validate_unlock_args(struct dlm_lkb *lkb, struct dlm_args *args)
 			goto out;
 		}
 		/* add_to_waiters() will set OVERLAP_UNLOCK */
-		goto out_ok;
 	}
 
-	/* normal unlock not allowed if there's any op in progress */
-	rv = -EBUSY;
-	if (lkb->lkb_wait_type || lkb->lkb_wait_count)
-		goto out;
-
  out_ok:
 	/* an overlapping op shouldn't blow away exflags from other op */
 	lkb->lkb_exflags |= args->flags;
-- 
2.31.1