[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/lock.c b/fs/gfs2/locking/dlm/lock.c
new file mode 100644
index 0000000..daf59d5
--- /dev/null
+++ b/fs/gfs2/locking/dlm/lock.c
@@ -0,0 +1,537 @@
+/******************************************************************************
+*******************************************************************************
+**
+** 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"
+
+static char junk_lvb[GDLM_LVB_SIZE];
+
+static void queue_complete(struct gdlm_lock *lp)
+{
+ struct gdlm_ls *ls = lp->ls;
+
+ clear_bit(LFL_ACTIVE, &lp->flags);
+
+ spin_lock(&ls->async_lock);
+ list_add_tail(&lp->clist, &ls->complete);
+ spin_unlock(&ls->async_lock);
+ wake_up(&ls->thread_wait);
+}
+
+static inline void gdlm_ast(void *astarg)
+{
+ queue_complete((struct gdlm_lock *) astarg);
+}
+
+static inline void gdlm_bast(void *astarg, int mode)
+{
+ struct gdlm_lock *lp = astarg;
+ struct gdlm_ls *ls = lp->ls;
+
+ if (!mode) {
+ printk("lock_dlm: bast mode zero %x,%"PRIx64"\n",
+ lp->lockname.ln_type, lp->lockname.ln_number);
+ return;
+ }
+
+ spin_lock(&ls->async_lock);
+ if (!lp->bast_mode) {
+ list_add_tail(&lp->blist, &ls->blocking);
+ lp->bast_mode = mode;
+ } else if (lp->bast_mode < mode)
+ lp->bast_mode = mode;
+ spin_unlock(&ls->async_lock);
+ wake_up(&ls->thread_wait);
+}
+
+void gdlm_queue_delayed(struct gdlm_lock *lp)
+{
+ struct gdlm_ls *ls = lp->ls;
+
+ spin_lock(&ls->async_lock);
+ list_add_tail(&lp->delay_list, &ls->delayed);
+ spin_unlock(&ls->async_lock);
+}
+
+/* convert gfs lock-state to dlm lock-mode */
+
+static int16_t make_mode(int16_t lmstate)
+{
+ switch (lmstate) {
+ case LM_ST_UNLOCKED:
+ return DLM_LOCK_NL;
+ case LM_ST_EXCLUSIVE:
+ return DLM_LOCK_EX;
+ case LM_ST_DEFERRED:
+ return DLM_LOCK_CW;
+ case LM_ST_SHARED:
+ return DLM_LOCK_PR;
+ default:
+ GDLM_ASSERT(0, printk("unknown LM state %d\n", lmstate););
+ }
+}
+
+/* convert dlm lock-mode to gfs lock-state */
+
+int16_t gdlm_make_lmstate(int16_t dlmmode)
+{
+ switch (dlmmode) {
+ case DLM_LOCK_IV:
+ case DLM_LOCK_NL:
+ return LM_ST_UNLOCKED;
+ case DLM_LOCK_EX:
+ return LM_ST_EXCLUSIVE;
+ case DLM_LOCK_CW:
+ return LM_ST_DEFERRED;
+ case DLM_LOCK_PR:
+ return LM_ST_SHARED;
+ default:
+ GDLM_ASSERT(0, printk("unknown DLM mode %d\n", dlmmode););
+ }
+}
+
+/* verify agreement with GFS on the current lock state, NB: DLM_LOCK_NL and
+ DLM_LOCK_IV are both considered LM_ST_UNLOCKED by GFS. */
+
+static void check_cur_state(struct gdlm_lock *lp, unsigned int cur_state)
+{
+ int16_t cur = make_mode(cur_state);
+ if (lp->cur != DLM_LOCK_IV)
+ GDLM_ASSERT(lp->cur == cur, printk("%d, %d\n", lp->cur, cur););
+}
+
+static inline unsigned int make_flags(struct gdlm_lock *lp,
+ unsigned int gfs_flags,
+ int16_t cur, int16_t req)
+{
+ unsigned int lkf = 0;
+
+ if (gfs_flags & LM_FLAG_TRY)
+ lkf |= DLM_LKF_NOQUEUE;
+
+ if (gfs_flags & LM_FLAG_TRY_1CB) {
+ lkf |= DLM_LKF_NOQUEUE;
+ lkf |= DLM_LKF_NOQUEUEBAST;
+ }
+
+ if (gfs_flags & LM_FLAG_PRIORITY) {
+ lkf |= DLM_LKF_NOORDER;
+ lkf |= DLM_LKF_HEADQUE;
+ }
+
+ if (gfs_flags & LM_FLAG_ANY) {
+ if (req == DLM_LOCK_PR)
+ lkf |= DLM_LKF_ALTCW;
+ else if (req == DLM_LOCK_CW)
+ lkf |= DLM_LKF_ALTPR;
+ }
+
+ if (lp->lksb.sb_lkid != 0) {
+ lkf |= DLM_LKF_CONVERT;
+
+ /* Conversion deadlock avoidance by DLM */
+
+ if (!test_bit(LFL_FORCE_PROMOTE, &lp->flags) &&
+ !(lkf & DLM_LKF_NOQUEUE) &&
+ cur > DLM_LOCK_NL && req > DLM_LOCK_NL && cur != req)
+ lkf |= DLM_LKF_CONVDEADLK;
+ }
+
+ if (lp->lvb)
+ lkf |= DLM_LKF_VALBLK;
+
+ return lkf;
+}
+
+/* make_strname - convert GFS lock numbers to a string */
+
+static inline void make_strname(struct lm_lockname *lockname,
+ struct gdlm_strname *str)
+{
+ sprintf(str->name, "%8x%16"PRIx64, lockname->ln_type,
+ lockname->ln_number);
+ str->namelen = GDLM_STRNAME_BYTES;
+}
+
+int gdlm_create_lp(struct gdlm_ls *ls, struct lm_lockname *name,
+ struct gdlm_lock **lpp)
+{
+ struct gdlm_lock *lp;
+
+ lp = kmalloc(sizeof(struct gdlm_lock), GFP_KERNEL);
+ if (!lp)
+ return -ENOMEM;
+
+ memset(lp, 0, sizeof(struct gdlm_lock));
+ lp->lockname = *name;
+ lp->ls = ls;
+ lp->cur = DLM_LOCK_IV;
+ lp->lvb = NULL;
+ lp->hold_null = NULL;
+ init_completion(&lp->ast_wait);
+ INIT_LIST_HEAD(&lp->clist);
+ INIT_LIST_HEAD(&lp->blist);
+ INIT_LIST_HEAD(&lp->delay_list);
+
+ spin_lock(&ls->async_lock);
+ list_add(&lp->all_list, &ls->all_locks);
+ ls->all_locks_count++;
+ spin_unlock(&ls->async_lock);
+
+ *lpp = lp;
+ return 0;
+}
+
+void gdlm_delete_lp(struct gdlm_lock *lp)
+{
+ struct gdlm_ls *ls = lp->ls;
+
+ spin_lock(&ls->async_lock);
+ if (!list_empty(&lp->clist))
+ list_del_init(&lp->clist);
+ if (!list_empty(&lp->blist))
+ list_del_init(&lp->blist);
+ if (!list_empty(&lp->delay_list))
+ list_del_init(&lp->delay_list);
+ GDLM_ASSERT(!list_empty(&lp->all_list),);
+ list_del_init(&lp->all_list);
+ ls->all_locks_count--;
+ spin_unlock(&ls->async_lock);
+
+ kfree(lp);
+}
+
+int gdlm_get_lock(lm_lockspace_t *lockspace, struct lm_lockname *name,
+ lm_lock_t **lockp)
+{
+ struct gdlm_lock *lp;
+ int error;
+
+ error = gdlm_create_lp((struct gdlm_ls *) lockspace, name, &lp);
+
+ *lockp = (lm_lock_t *) lp;
+ return error;
+}
+
+void gdlm_put_lock(lm_lock_t *lock)
+{
+ gdlm_delete_lp((struct gdlm_lock *) lock);
+}
+
+void gdlm_do_lock(struct gdlm_lock *lp, struct dlm_range *range)
+{
+ struct gdlm_ls *ls = lp->ls;
+ struct gdlm_strname str;
+ int error, bast = 1;
+
+ /*
+ * When recovery is in progress, delay lock requests for submission
+ * once recovery is done. Requests for recovery (NOEXP) and unlocks
+ * can pass.
+ */
+
+ if (test_bit(DFL_BLOCK_LOCKS, &ls->flags) &&
+ !test_bit(LFL_NOBLOCK, &lp->flags) && lp->req != DLM_LOCK_NL) {
+ gdlm_queue_delayed(lp);
+ return;
+ }
+
+ /*
+ * Submit the actual lock request.
+ */
+
+ if (test_bit(LFL_NOBAST, &lp->flags))
+ bast = 0;
+
+ make_strname(&lp->lockname, &str);
+
+ set_bit(LFL_ACTIVE, &lp->flags);
+
+ log_debug("lk %x,%"PRIx64" id %x %d,%d %x", lp->lockname.ln_type,
+ lp->lockname.ln_number, lp->lksb.sb_lkid,
+ lp->cur, lp->req, lp->lkf);
+
+ error = dlm_lock(ls->dlm_lockspace, lp->req, &lp->lksb, lp->lkf,
+ str.name, str.namelen, 0, gdlm_ast, (void *) lp,
+ bast ? gdlm_bast : NULL, range);
+
+ if ((error == -EAGAIN) && (lp->lkf & DLM_LKF_NOQUEUE)) {
+ lp->lksb.sb_status = -EAGAIN;
+ queue_complete(lp);
+ error = 0;
+ }
+
+ GDLM_ASSERT(!error,
+ printk("%s: num=%x,%"PRIx64" err=%d cur=%d req=%d lkf=%x\n",
+ ls->fsname, lp->lockname.ln_type,
+ lp->lockname.ln_number, error, lp->cur, lp->req,
+ lp->lkf););
+}
+
+void gdlm_do_unlock(struct gdlm_lock *lp)
+{
+ unsigned int lkf = 0;
+ int error;
+
+ set_bit(LFL_DLM_UNLOCK, &lp->flags);
+ set_bit(LFL_ACTIVE, &lp->flags);
+
+ if (lp->lvb)
+ lkf = DLM_LKF_VALBLK;
+
+ log_debug("un %x,%"PRIx64" %x %d %x", lp->lockname.ln_type,
+ lp->lockname.ln_number, lp->lksb.sb_lkid, lp->cur, lkf);
+
+ error = dlm_unlock(lp->ls->dlm_lockspace, lp->lksb.sb_lkid, lkf,
+ NULL, lp);
+
+ GDLM_ASSERT(!error,
+ printk("%s: error=%d num=%x,%"PRIx64" lkf=%x flags=%lx\n",
+ lp->ls->fsname, error, lp->lockname.ln_type,
+ lp->lockname.ln_number, lkf, lp->flags););
+}
+
+unsigned int gdlm_lock(lm_lock_t *lock, unsigned int cur_state,
+ unsigned int req_state, unsigned int flags)
+{
+ struct gdlm_lock *lp = (struct gdlm_lock *) lock;
+
+ clear_bit(LFL_DLM_CANCEL, &lp->flags);
+ if (flags & LM_FLAG_NOEXP)
+ set_bit(LFL_NOBLOCK, &lp->flags);
+
+ check_cur_state(lp, cur_state);
+ lp->req = make_mode(req_state);
+ lp->lkf = make_flags(lp, flags, lp->cur, lp->req);
+
+ gdlm_do_lock(lp, NULL);
+ return LM_OUT_ASYNC;
+}
+
+unsigned int gdlm_unlock(lm_lock_t *lock, unsigned int cur_state)
+{
+ struct gdlm_lock *lp = (struct gdlm_lock *) lock;
+
+ clear_bit(LFL_DLM_CANCEL, &lp->flags);
+ if (lp->cur == DLM_LOCK_IV)
+ return 0;
+ gdlm_do_unlock(lp);
+ return LM_OUT_ASYNC;
+}
+
+void gdlm_cancel(lm_lock_t *lock)
+{
+ struct gdlm_lock *lp = (struct gdlm_lock *) lock;
+ struct gdlm_ls *ls = lp->ls;
+ int error, delay_list = 0;
+
+ if (test_bit(LFL_DLM_CANCEL, &lp->flags))
+ return;
+
+ log_all("gdlm_cancel %x,%"PRIx64" flags %lx",
+ lp->lockname.ln_type, lp->lockname.ln_number, lp->flags);
+
+ spin_lock(&ls->async_lock);
+ if (!list_empty(&lp->delay_list)) {
+ list_del_init(&lp->delay_list);
+ delay_list = 1;
+ }
+ spin_unlock(&ls->async_lock);
+
+ if (delay_list) {
+ set_bit(LFL_CANCEL, &lp->flags);
+ set_bit(LFL_ACTIVE, &lp->flags);
+ queue_complete(lp);
+ return;
+ }
+
+ if (!test_bit(LFL_ACTIVE, &lp->flags) ||
+ test_bit(LFL_DLM_UNLOCK, &lp->flags)) {
+ log_all("gdlm_cancel skip %x,%"PRIx64" flags %lx",
+ lp->lockname.ln_type, lp->lockname.ln_number,
+ lp->flags);
+ return;
+ }
+
+ /* the lock is blocked in the dlm */
+
+ set_bit(LFL_DLM_CANCEL, &lp->flags);
+ set_bit(LFL_ACTIVE, &lp->flags);
+
+ error = dlm_unlock(ls->dlm_lockspace, lp->lksb.sb_lkid, DLM_LKF_CANCEL,
+ NULL, lp);
+
+ log_all("gdlm_cancel rv %d %x,%"PRIx64" flags %lx", error,
+ lp->lockname.ln_type, lp->lockname.ln_number, lp->flags);
+
+ if (error == -EBUSY)
+ clear_bit(LFL_DLM_CANCEL, &lp->flags);
+}
+
+int gdlm_add_lvb(struct gdlm_lock *lp)
+{
+ char *lvb;
+
+ lvb = kmalloc(GDLM_LVB_SIZE, GFP_KERNEL);
+ if (!lvb)
+ return -ENOMEM;
+
+ memset(lvb, 0, GDLM_LVB_SIZE);
+
+ lp->lksb.sb_lvbptr = lvb;
+ lp->lvb = lvb;
+ return 0;
+}
+
+void gdlm_del_lvb(struct gdlm_lock *lp)
+{
+ kfree(lp->lvb);
+ lp->lvb = NULL;
+ lp->lksb.sb_lvbptr = NULL;
+}
+
+/* This can do a synchronous dlm request (requiring a lock_dlm thread to get
+ the completion) because gfs won't call hold_lvb() during a callback (from
+ the context of a lock_dlm thread). */
+
+static int hold_null_lock(struct gdlm_lock *lp)
+{
+ struct gdlm_lock *lpn = NULL;
+ int error;
+
+ if (lp->hold_null) {
+ printk("lock_dlm: lvb already held\n");
+ return 0;
+ }
+
+ error = gdlm_create_lp(lp->ls, &lp->lockname, &lpn);
+ if (error)
+ goto out;
+
+ lpn->lksb.sb_lvbptr = junk_lvb;
+ lpn->lvb = junk_lvb;
+
+ lpn->req = DLM_LOCK_NL;
+ lpn->lkf = DLM_LKF_VALBLK | DLM_LKF_EXPEDITE;
+ set_bit(LFL_NOBAST, &lpn->flags);
+ set_bit(LFL_INLOCK, &lpn->flags);
+
+ init_completion(&lpn->ast_wait);
+ gdlm_do_lock(lpn, NULL);
+ wait_for_completion(&lpn->ast_wait);
+ error = lp->lksb.sb_status;
+ if (error) {
+ printk("lock_dlm: hold_null_lock dlm error %d\n", error);
+ gdlm_delete_lp(lpn);
+ lpn = NULL;
+ }
+ out:
+ lp->hold_null = lpn;
+ return error;
+}
+
+/* This cannot do a synchronous dlm request (requiring a lock_dlm thread to get
+ the completion) because gfs may call unhold_lvb() during a callback (from
+ the context of a lock_dlm thread) which could cause a deadlock since the
+ other lock_dlm thread could be engaged in recovery. */
+
+static void unhold_null_lock(struct gdlm_lock *lp)
+{
+ struct gdlm_lock *lpn = lp->hold_null;
+
+ GDLM_ASSERT(lpn,);
+ lpn->lksb.sb_lvbptr = NULL;
+ lpn->lvb = NULL;
+ set_bit(LFL_UNLOCK_DELETE, &lpn->flags);
+ gdlm_do_unlock(lpn);
+ lp->hold_null = NULL;
+}
+
+/* Acquire a NL lock because gfs requires the value block to remain
+ intact on the resource while the lvb is "held" even if it's holding no locks
+ on the resource. */
+
+int gdlm_hold_lvb(lm_lock_t *lock, char **lvbp)
+{
+ struct gdlm_lock *lp = (struct gdlm_lock *) lock;
+ int error;
+
+ error = gdlm_add_lvb(lp);
+ if (error)
+ return error;
+
+ *lvbp = lp->lvb;
+
+ error = hold_null_lock(lp);
+ if (error)
+ gdlm_del_lvb(lp);
+
+ return error;
+}
+
+void gdlm_unhold_lvb(lm_lock_t *lock, char *lvb)
+{
+ struct gdlm_lock *lp = (struct gdlm_lock *) lock;
+
+ unhold_null_lock(lp);
+ gdlm_del_lvb(lp);
+}
+
+void gdlm_sync_lvb(lm_lock_t *lock, char *lvb)
+{
+ struct gdlm_lock *lp = (struct gdlm_lock *) lock;
+
+ if (lp->cur != DLM_LOCK_EX)
+ return;
+
+ init_completion(&lp->ast_wait);
+ set_bit(LFL_SYNC_LVB, &lp->flags);
+
+ lp->req = DLM_LOCK_EX;
+ lp->lkf = make_flags(lp, 0, lp->cur, lp->req);
+
+ gdlm_do_lock(lp, NULL);
+ wait_for_completion(&lp->ast_wait);
+}
+
+void gdlm_submit_delayed(struct gdlm_ls *ls)
+{
+ struct gdlm_lock *lp, *safe;
+
+ spin_lock(&ls->async_lock);
+ list_for_each_entry_safe(lp, safe, &ls->delayed, delay_list) {
+ list_del_init(&lp->delay_list);
+ list_add_tail(&lp->delay_list, &ls->submit);
+ }
+ spin_unlock(&ls->async_lock);
+ wake_up(&ls->thread_wait);
+}
+
+int gdlm_release_all_locks(struct gdlm_ls *ls)
+{
+ struct gdlm_lock *lp, *safe;
+ int count = 0;
+
+ spin_lock(&ls->async_lock);
+ list_for_each_entry_safe(lp, safe, &ls->all_locks, all_list) {
+ list_del_init(&lp->all_list);
+
+ if (lp->lvb && lp->lvb != junk_lvb)
+ kfree(lp->lvb);
+ kfree(lp);
+ count++;
+ }
+ spin_unlock(&ls->async_lock);
+
+ return count;
+}
+