Commit 420ba3cd authored by Alexander Aring's avatar Alexander Aring Committed by David Teigland
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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: default avatarAlexander Aring <aahringo@redhat.com>
Signed-off-by: default avatarDavid Teigland <teigland@redhat.com>
parent 44637ca4

fs/dlm/lock.c

+22 −22
Original line number Diff line number Diff line
@@ -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;