fs: dlm: handle -EBUSY first in unlock validation

This patch checks for -EBUSY conditions in dlm_unlock() before
checking for -EINVAL conditions (except for CANCEL and
FORCEUNLOCK calls where a busy condition is expected.)
There are no problems with the current ordering of checks,
but this makes dlm_unlock() consistent with dlm_lock(), and
may avoid future problems if other checks are added.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index c23413da40f5a59295ef6b1e4a3ab059a05a5b7a..16d339d383cdd1a94989baf9955210b706f0c64b 100644 (file)
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -2918,23 +2918,12 @@ 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 */
@@ -2949,7 +2938,24 @@ 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;
        }
 
@@ -3022,14 +3028,8 @@ 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;