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Commit 8b4021fa authored by David Teigland's avatar David Teigland Committed by Steven Whitehouse
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[DLM] canceling deadlocked lock 



Add a function that can be used through libdlm by a system daemon to cancel
another process's deadlocked lock.  A completion ast with EDEADLK is returned
to the process waiting for the lock.

Signed-off-by: default avatarDavid Teigland <teigland@redhat.com>
Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
parent 84d8cd69

fs/dlm/dlm_internal.h

+1 −0
Original line number Diff line number Diff line
@@ -216,6 +216,7 @@ struct dlm_args { 
#define DLM_IFL_ENDOFLIFE	0x00200000

#define DLM_IFL_WATCH_TIMEWARN	0x00400000

#define DLM_IFL_TIMEOUT_CANCEL	0x00800000

#define DLM_IFL_DEADLOCK_CANCEL	0x01000000

#define DLM_IFL_USER		0x00000001

#define DLM_IFL_ORPHAN		0x00000002

fs/dlm/lock.c

+53 −0
Original line number Diff line number Diff line
@@ -300,6 +300,11 @@ static void queue_cast(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv) 
		rv = -ETIMEDOUT;

	}



	if (rv == -DLM_ECANCEL && (lkb->lkb_flags & DLM_IFL_DEADLOCK_CANCEL)) {

		lkb->lkb_flags &= ~DLM_IFL_DEADLOCK_CANCEL;

		rv = -EDEADLK;

	}



	lkb->lkb_lksb->sb_status = rv;

	lkb->lkb_lksb->sb_flags = lkb->lkb_sbflags;
@@ -4450,6 +4455,54 @@ int dlm_user_cancel(struct dlm_ls *ls, struct dlm_user_args *ua_tmp, 
	return error;

}



int dlm_user_deadlock(struct dlm_ls *ls, uint32_t flags, uint32_t lkid)

{

	struct dlm_lkb *lkb;

	struct dlm_args args;

	struct dlm_user_args *ua;

	struct dlm_rsb *r;

	int error;



	dlm_lock_recovery(ls);



	error = find_lkb(ls, lkid, &lkb);

	if (error)

		goto out;



	ua = (struct dlm_user_args *)lkb->lkb_astparam;



	error = set_unlock_args(flags, ua, &args);

	if (error)

		goto out_put;



	/* same as cancel_lock(), but set DEADLOCK_CANCEL after lock_rsb */



	r = lkb->lkb_resource;

	hold_rsb(r);

	lock_rsb(r);



	error = validate_unlock_args(lkb, &args);

	if (error)

		goto out_r;

	lkb->lkb_flags |= DLM_IFL_DEADLOCK_CANCEL;



	error = _cancel_lock(r, lkb);

 out_r:

	unlock_rsb(r);

	put_rsb(r);



	if (error == -DLM_ECANCEL)

		error = 0;

	/* from validate_unlock_args() */

	if (error == -EBUSY)

		error = 0;

 out_put:

	dlm_put_lkb(lkb);

 out:

	dlm_unlock_recovery(ls);

	return error;

}



/* lkb's that are removed from the waiters list by revert are just left on the

   orphans list with the granted orphan locks, to be freed by purge */

fs/dlm/lock.h

+1 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ int dlm_user_cancel(struct dlm_ls *ls, struct dlm_user_args *ua_tmp, 
	uint32_t flags, uint32_t lkid);

int dlm_user_purge(struct dlm_ls *ls, struct dlm_user_proc *proc,

	int nodeid, int pid);

int dlm_user_deadlock(struct dlm_ls *ls, uint32_t flags, uint32_t lkid);

void dlm_clear_proc_locks(struct dlm_ls *ls, struct dlm_user_proc *proc);



static inline int is_master(struct dlm_rsb *r)

fs/dlm/user.c

+25 −0
Original line number Diff line number Diff line
@@ -156,6 +156,7 @@ static int lkb_is_endoflife(struct dlm_lkb *lkb, int sb_status, int type) 
		return 1;

	case -DLM_ECANCEL:

	case -ETIMEDOUT:

	case -EDEADLK:

		if (lkb->lkb_grmode == DLM_LOCK_IV)

			return 1;

		break;
@@ -320,6 +321,22 @@ static int device_user_unlock(struct dlm_user_proc *proc, 
	return error;

}



static int device_user_deadlock(struct dlm_user_proc *proc,

				struct dlm_lock_params *params)

{

	struct dlm_ls *ls;

	int error;



	ls = dlm_find_lockspace_local(proc->lockspace);

	if (!ls)

		return -ENOENT;



	error = dlm_user_deadlock(ls, params->flags, params->lkid);



	dlm_put_lockspace(ls);

	return error;

}



static int create_misc_device(struct dlm_ls *ls, char *name)

{

	int error, len;
@@ -545,6 +562,14 @@ static ssize_t device_write(struct file *file, const char __user *buf, 
		error = device_user_unlock(proc, &kbuf->i.lock);

		break;



	case DLM_USER_DEADLOCK:

		if (!proc) {

			log_print("no locking on control device");

			goto out_sig;

		}

		error = device_user_deadlock(proc, &kbuf->i.lock);

		break;



	case DLM_USER_CREATE_LOCKSPACE:

		if (proc) {

			log_print("create/remove only on control device");

include/linux/dlm_device.h

+1 −0
Original line number Diff line number Diff line
@@ -92,6 +92,7 @@ struct dlm_lock_result { 
#define DLM_USER_CREATE_LOCKSPACE  4

#define DLM_USER_REMOVE_LOCKSPACE  5

#define DLM_USER_PURGE        6

#define DLM_USER_DEADLOCK     7



/* Arbitrary length restriction */

#define MAX_LS_NAME_LEN 64