[GFS2] The lock modules for GFS2
This patch contains the pluggable locking modules
for GFS2.
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/locking/dlm/thread.c b/fs/gfs2/locking/dlm/thread.c
new file mode 100644
index 0000000..22bbe6d
--- /dev/null
+++ b/fs/gfs2/locking/dlm/thread.c
@@ -0,0 +1,359 @@
+/******************************************************************************
+*******************************************************************************
+**
+** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
+** Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
+**
+** This copyrighted material is made available to anyone wishing to use,
+** modify, copy, or redistribute it subject to the terms and conditions
+** of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include "lock_dlm.h"
+
+/* A lock placed on this queue is re-submitted to DLM as soon as the lock_dlm
+ thread gets to it. */
+
+static void queue_submit(struct gdlm_lock *lp)
+{
+ struct gdlm_ls *ls = lp->ls;
+
+ spin_lock(&ls->async_lock);
+ list_add_tail(&lp->delay_list, &ls->submit);
+ spin_unlock(&ls->async_lock);
+ wake_up(&ls->thread_wait);
+}
+
+static void process_submit(struct gdlm_lock *lp)
+{
+ gdlm_do_lock(lp, NULL);
+}
+
+static void process_blocking(struct gdlm_lock *lp, int bast_mode)
+{
+ struct gdlm_ls *ls = lp->ls;
+ unsigned int cb;
+
+ switch (gdlm_make_lmstate(bast_mode)) {
+ case LM_ST_EXCLUSIVE:
+ cb = LM_CB_NEED_E;
+ break;
+ case LM_ST_DEFERRED:
+ cb = LM_CB_NEED_D;
+ break;
+ case LM_ST_SHARED:
+ cb = LM_CB_NEED_S;
+ break;
+ default:
+ GDLM_ASSERT(0, printk("unknown bast mode %u\n",lp->bast_mode););
+ }
+
+ ls->fscb(ls->fsdata, cb, &lp->lockname);
+}
+
+static void process_complete(struct gdlm_lock *lp)
+{
+ struct gdlm_ls *ls = lp->ls;
+ struct lm_async_cb acb;
+ int16_t prev_mode = lp->cur;
+
+ memset(&acb, 0, sizeof(acb));
+
+ if (lp->lksb.sb_status == -DLM_ECANCEL) {
+ log_all("complete dlm cancel %x,%"PRIx64" flags %lx",
+ lp->lockname.ln_type, lp->lockname.ln_number,
+ lp->flags);
+
+ lp->req = lp->cur;
+ acb.lc_ret |= LM_OUT_CANCELED;
+ if (lp->cur == DLM_LOCK_IV)
+ lp->lksb.sb_lkid = 0;
+ goto out;
+ }
+
+ if (test_and_clear_bit(LFL_DLM_UNLOCK, &lp->flags)) {
+ if (lp->lksb.sb_status != -DLM_EUNLOCK) {
+ log_all("unlock sb_status %d %x,%"PRIx64" flags %lx",
+ lp->lksb.sb_status, lp->lockname.ln_type,
+ lp->lockname.ln_number, lp->flags);
+ return;
+ }
+
+ lp->cur = DLM_LOCK_IV;
+ lp->req = DLM_LOCK_IV;
+ lp->lksb.sb_lkid = 0;
+
+ if (test_and_clear_bit(LFL_UNLOCK_DELETE, &lp->flags)) {
+ gdlm_delete_lp(lp);
+ return;
+ }
+ goto out;
+ }
+
+ if (lp->lksb.sb_flags & DLM_SBF_VALNOTVALID)
+ memset(lp->lksb.sb_lvbptr, 0, GDLM_LVB_SIZE);
+
+ if (lp->lksb.sb_flags & DLM_SBF_ALTMODE) {
+ if (lp->req == DLM_LOCK_PR)
+ lp->req = DLM_LOCK_CW;
+ else if (lp->req == DLM_LOCK_CW)
+ lp->req = DLM_LOCK_PR;
+ }
+
+ /*
+ * A canceled lock request. The lock was just taken off the delayed
+ * list and was never even submitted to dlm.
+ */
+
+ if (test_and_clear_bit(LFL_CANCEL, &lp->flags)) {
+ log_all("complete internal cancel %x,%"PRIx64"",
+ lp->lockname.ln_type, lp->lockname.ln_number);
+ lp->req = lp->cur;
+ acb.lc_ret |= LM_OUT_CANCELED;
+ goto out;
+ }
+
+ /*
+ * An error occured.
+ */
+
+ if (lp->lksb.sb_status) {
+ /* a "normal" error */
+ if ((lp->lksb.sb_status == -EAGAIN) &&
+ (lp->lkf & DLM_LKF_NOQUEUE)) {
+ lp->req = lp->cur;
+ if (lp->cur == DLM_LOCK_IV)
+ lp->lksb.sb_lkid = 0;
+ goto out;
+ }
+
+ /* this could only happen with cancels I think */
+ log_all("ast sb_status %d %x,%"PRIx64" flags %lx",
+ lp->lksb.sb_status, lp->lockname.ln_type,
+ lp->lockname.ln_number, lp->flags);
+ return;
+ }
+
+ /*
+ * This is an AST for an EX->EX conversion for sync_lvb from GFS.
+ */
+
+ if (test_and_clear_bit(LFL_SYNC_LVB, &lp->flags)) {
+ complete(&lp->ast_wait);
+ return;
+ }
+
+ /*
+ * A lock has been demoted to NL because it initially completed during
+ * BLOCK_LOCKS. Now it must be requested in the originally requested
+ * mode.
+ */
+
+ if (test_and_clear_bit(LFL_REREQUEST, &lp->flags)) {
+ GDLM_ASSERT(lp->req == DLM_LOCK_NL,);
+ GDLM_ASSERT(lp->prev_req > DLM_LOCK_NL,);
+
+ lp->cur = DLM_LOCK_NL;
+ lp->req = lp->prev_req;
+ lp->prev_req = DLM_LOCK_IV;
+ lp->lkf &= ~DLM_LKF_CONVDEADLK;
+
+ set_bit(LFL_NOCACHE, &lp->flags);
+
+ if (test_bit(DFL_BLOCK_LOCKS, &ls->flags) &&
+ !test_bit(LFL_NOBLOCK, &lp->flags))
+ gdlm_queue_delayed(lp);
+ else
+ queue_submit(lp);
+ return;
+ }
+
+ /*
+ * A request is granted during dlm recovery. It may be granted
+ * because the locks of a failed node were cleared. In that case,
+ * there may be inconsistent data beneath this lock and we must wait
+ * for recovery to complete to use it. When gfs recovery is done this
+ * granted lock will be converted to NL and then reacquired in this
+ * granted state.
+ */
+
+ if (test_bit(DFL_BLOCK_LOCKS, &ls->flags) &&
+ !test_bit(LFL_NOBLOCK, &lp->flags) &&
+ lp->req != DLM_LOCK_NL) {
+
+ lp->cur = lp->req;
+ lp->prev_req = lp->req;
+ lp->req = DLM_LOCK_NL;
+ lp->lkf |= DLM_LKF_CONVERT;
+ lp->lkf &= ~DLM_LKF_CONVDEADLK;
+
+ log_debug("rereq %x,%"PRIx64" id %x %d,%d",
+ lp->lockname.ln_type, lp->lockname.ln_number,
+ lp->lksb.sb_lkid, lp->cur, lp->req);
+
+ set_bit(LFL_REREQUEST, &lp->flags);
+ queue_submit(lp);
+ return;
+ }
+
+ /*
+ * DLM demoted the lock to NL before it was granted so GFS must be
+ * told it cannot cache data for this lock.
+ */
+
+ if (lp->lksb.sb_flags & DLM_SBF_DEMOTED)
+ set_bit(LFL_NOCACHE, &lp->flags);
+
+ out:
+ /*
+ * This is an internal lock_dlm lock
+ */
+
+ if (test_bit(LFL_INLOCK, &lp->flags)) {
+ clear_bit(LFL_NOBLOCK, &lp->flags);
+ lp->cur = lp->req;
+ complete(&lp->ast_wait);
+ return;
+ }
+
+ /*
+ * Normal completion of a lock request. Tell GFS it now has the lock.
+ */
+
+ clear_bit(LFL_NOBLOCK, &lp->flags);
+ lp->cur = lp->req;
+
+ acb.lc_name = lp->lockname;
+ acb.lc_ret |= gdlm_make_lmstate(lp->cur);
+
+ if (!test_and_clear_bit(LFL_NOCACHE, &lp->flags) &&
+ (lp->cur > DLM_LOCK_NL) && (prev_mode > DLM_LOCK_NL))
+ acb.lc_ret |= LM_OUT_CACHEABLE;
+
+ ls->fscb(ls->fsdata, LM_CB_ASYNC, &acb);
+}
+
+static inline int no_work(struct gdlm_ls *ls, int blocking)
+{
+ int ret;
+
+ spin_lock(&ls->async_lock);
+ ret = list_empty(&ls->complete) && list_empty(&ls->submit);
+ if (ret && blocking)
+ ret = list_empty(&ls->blocking);
+ spin_unlock(&ls->async_lock);
+
+ return ret;
+}
+
+static inline int check_drop(struct gdlm_ls *ls)
+{
+ if (!ls->drop_locks_count)
+ return 0;
+
+ if (time_after(jiffies, ls->drop_time + ls->drop_locks_period * HZ)) {
+ ls->drop_time = jiffies;
+ if (ls->all_locks_count >= ls->drop_locks_count)
+ return 1;
+ }
+ return 0;
+}
+
+static int gdlm_thread(void *data)
+{
+ struct gdlm_ls *ls = (struct gdlm_ls *) data;
+ struct gdlm_lock *lp = NULL;
+ int blist = 0;
+ uint8_t complete, blocking, submit, drop;
+ DECLARE_WAITQUEUE(wait, current);
+
+ /* Only thread1 is allowed to do blocking callbacks since gfs
+ may wait for a completion callback within a blocking cb. */
+
+ if (current == ls->thread1)
+ blist = 1;
+
+ while (!kthread_should_stop()) {
+ set_current_state(TASK_INTERRUPTIBLE);
+ add_wait_queue(&ls->thread_wait, &wait);
+ if (no_work(ls, blist))
+ schedule();
+ remove_wait_queue(&ls->thread_wait, &wait);
+ set_current_state(TASK_RUNNING);
+
+ complete = blocking = submit = drop = 0;
+
+ spin_lock(&ls->async_lock);
+
+ if (blist && !list_empty(&ls->blocking)) {
+ lp = list_entry(ls->blocking.next, struct gdlm_lock,
+ blist);
+ list_del_init(&lp->blist);
+ blocking = lp->bast_mode;
+ lp->bast_mode = 0;
+ } else if (!list_empty(&ls->complete)) {
+ lp = list_entry(ls->complete.next, struct gdlm_lock,
+ clist);
+ list_del_init(&lp->clist);
+ complete = 1;
+ } else if (!list_empty(&ls->submit)) {
+ lp = list_entry(ls->submit.next, struct gdlm_lock,
+ delay_list);
+ list_del_init(&lp->delay_list);
+ submit = 1;
+ }
+
+ drop = check_drop(ls);
+ spin_unlock(&ls->async_lock);
+
+ if (complete)
+ process_complete(lp);
+
+ else if (blocking)
+ process_blocking(lp, blocking);
+
+ else if (submit)
+ process_submit(lp);
+
+ if (drop)
+ ls->fscb(ls->fsdata, LM_CB_DROPLOCKS, NULL);
+
+ schedule();
+ }
+
+ return 0;
+}
+
+int gdlm_init_threads(struct gdlm_ls *ls)
+{
+ struct task_struct *p;
+ int error;
+
+ p = kthread_run(gdlm_thread, ls, "lock_dlm1");
+ error = IS_ERR(p);
+ if (error) {
+ log_all("can't start lock_dlm1 thread %d", error);
+ return error;
+ }
+ ls->thread1 = p;
+
+ p = kthread_run(gdlm_thread, ls, "lock_dlm2");
+ error = IS_ERR(p);
+ if (error) {
+ log_all("can't start lock_dlm2 thread %d", error);
+ kthread_stop(ls->thread1);
+ return error;
+ }
+ ls->thread2 = p;
+
+ return 0;
+}
+
+void gdlm_release_threads(struct gdlm_ls *ls)
+{
+ kthread_stop(ls->thread1);
+ kthread_stop(ls->thread2);
+}
+