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Message-Id: <11839970324005-git-send-email-swhiteho@redhat.com>
Date: Mon, 9 Jul 2007 17:02:27 +0100
From: swhiteho@...hat.com
To: linux-kernel@...r.kernel.org
Cc: cluster-devel@...hat.com, David Teigland <teigland@...hat.com>,
Steven Whitehouse <swhiteho@...hat.com>
Subject: [PATCH] [DLM] canceling deadlocked lock
From: David Teigland <teigland@...hat.com>
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: David Teigland <teigland@...hat.com>
Signed-off-by: Steven Whitehouse <swhiteho@...hat.com>
diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index a7435a8..a006fa5 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -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
diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index df91578..de943af 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -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 */
diff --git a/fs/dlm/lock.h b/fs/dlm/lock.h
index 99ab463..1720313 100644
--- a/fs/dlm/lock.h
+++ b/fs/dlm/lock.h
@@ -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)
diff --git a/fs/dlm/user.c b/fs/dlm/user.c
index 329da1b..6438941 100644
--- a/fs/dlm/user.c
+++ b/fs/dlm/user.c
@@ -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");
diff --git a/include/linux/dlm_device.h b/include/linux/dlm_device.h
index f7b9b57..9642277 100644
--- a/include/linux/dlm_device.h
+++ b/include/linux/dlm_device.h
@@ -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
--
1.5.1.2
-
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